WO2016170788A1 - Rubber composition, transmission belt and manufacturing method thereof - Google Patents

Abstract

This rubber composition contains a rubber component and cellulose-based fine fibers. The distribution range of fiber diameters of the cellulose-based fine fibers includes 50-500 nm. At least part of the belt main body (10) of the transmission belt B is formed from the rubber composition which contains the cellulose-based fine fibers having a fiber diameter distribution range that includes 50-500 nm.

Description

Rubber composition, power transmission belt and manufacturing method thereof

The present invention relates to a rubber composition, a transmission belt using the rubber composition, and a manufacturing method thereof.

A rubber composition containing a so-called cellulose nanofiber is known. For example, Patent Document 1 discloses a vulcanized rubber composition containing a rubber component such as natural rubber and chemically modified microfibril cellulose.

Also, it is known to apply such a rubber composition to a transmission belt. For example, Patent Document 2 discloses that a rubber composition in which a cellulose fine fiber having a carboxy group having an average fiber diameter of 0.1 to 200 nm is subjected to a hydrophobic modification treatment is applied to a transmission belt. . Furthermore, Patent Document 3 discloses that a rubber composition containing cellulose nanofibers is applied to the inner surface rubber layer of a flat belt.

Japanese Patent No. 4581116 JP 2014-125607 A JP2015-31315A

An object of the present invention is to provide a rubber composition capable of improving the friction and wear characteristics of rubber parts, and to improve the durability of a transmission belt made of the rubber composition.

The rubber composition of the present invention contains cellulosic fine fibers and a rubber component, and the fiber diameter distribution range of the cellulosic fine fibers contains 50 to 500 nm. In the power transmission belt of the present invention, at least a part of the belt main body is formed of a rubber composition containing cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm.

The rubber composition of the present invention contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm, and therefore has excellent behavioral stability under wet conditions. Further, according to the transmission belt of the present disclosure, at least a part of the belt main body is formed of a rubber composition containing cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. Sex can be obtained.

FIG. 1 is a perspective view schematically showing a wrapped V-belt of the embodiment. FIGS. 2A to 2G are explanatory views showing a method for manufacturing a wrapped V-belt. FIG. 3 is a perspective view schematically showing an exemplary V-ribbed belt of the second embodiment. FIG. 4 is a cross-sectional view of a main part of the V-ribbed belt of the second embodiment. FIG. 5 is a diagram showing a pulley layout of an auxiliary drive belt transmission device for an automobile using the V-ribbed belt of the second embodiment. FIG. 6 is a first explanatory view showing a method of manufacturing the V-ribbed belt of the second embodiment. FIG. 7 is a second explanatory view showing the method for manufacturing the V-ribbed belt of the second embodiment. FIG. 8 is a third explanatory view showing the method for manufacturing the V-ribbed belt of the second embodiment. FIG. 9 is a fourth explanatory view showing the method for manufacturing the V-ribbed belt of the second embodiment. FIG. 10 is a fifth explanatory view showing the method of manufacturing the V-ribbed belt of the second embodiment. FIG. 11 is a sixth explanatory view showing the method for manufacturing the V-ribbed belt of the second embodiment. FIG. 12 is a perspective view schematically showing an exemplary flat belt according to the third embodiment. FIG. 13 is a first explanatory view showing the flat belt manufacturing method according to the third embodiment. FIG. 14 is a second explanatory view showing the flat belt manufacturing method according to the third embodiment. FIG. 15 is a third explanatory view showing the flat belt manufacturing method according to the third embodiment. FIG. 16 is a diagram showing the configuration of the friction coefficient measuring apparatus. FIG. 17 is a diagram showing a pulley layout of a belt running tester for wear resistance evaluation. FIG. 18 is a diagram showing a pulley layout of a belt running test machine for evaluating bending fatigue resistance. FIG. 19 is a diagram showing a pulley layout of a belt running test machine for evaluating friction / wear characteristics. FIG. 20 is a diagram showing a pulley layout of a belt running test machine for wear resistance evaluation. FIG. 21 is a perspective view of the V-ribbed belt of the fourth embodiment. FIG. 22 is a cross-sectional view of a main part of the V-ribbed belt of the fourth embodiment. FIG. 23 is a diagram showing a pulley layout of an auxiliary drive belt transmission device for an automobile using the V-ribbed belt of the fourth embodiment. FIG. 24 is a first explanatory view showing the method of manufacturing the V-ribbed belt of the fourth embodiment. FIG. 25 is a second explanatory view showing the method for manufacturing the V-ribbed belt of the fourth embodiment. FIG. 26 is a third explanatory view showing the method of manufacturing the V-ribbed belt of the fourth embodiment. FIG. 27 is a fourth explanatory view showing the method of manufacturing the V-ribbed belt of the fourth embodiment. FIG. 28 is a fifth explanatory view showing the method of manufacturing the V-ribbed belt of the fourth embodiment. FIG. 29 is a sixth explanatory view illustrating the method of manufacturing the V-ribbed belt of the fourth embodiment. FIG. 30 is a cross-sectional view of a main part of the V-ribbed belt of the sixth embodiment. FIG. 31 is a perspective view of a modified V-ribbed belt. FIG. 32 is a sectional view of a flat belt. FIG. 33 is a diagram showing a pulley layout of a belt test traveling machine for durability evaluation. FIG. 34 is a diagram showing a pulley layout of a belt test traveling machine for durability evaluation. FIG. 35 shows a friction coefficient measuring apparatus. FIG. 36 is a diagram showing a pulley layout of a belt running test machine for evaluating abnormal noise when wet. FIG. 37 is a perspective view schematically showing an exemplary toothed belt of the seventh embodiment. FIG. 38 is a partial cross-sectional view of a belt forming die used for manufacturing the toothed belt of the seventh embodiment. FIG. 39 is a first explanatory view of the manufacturing method of the toothed belt according to the seventh embodiment. FIG. 40 is a second explanatory view of the manufacturing method of the toothed belt according to the seventh embodiment. FIG. 41 is a third explanatory view of the manufacturing method of the toothed belt according to the seventh embodiment. FIG. 42 is a first explanatory view of the manufacturing method of the toothed belt according to the eighth embodiment. FIG. 43 is a second explanatory view of the manufacturing method of the toothed belt according to the eighth embodiment. FIG. 44 is a third explanatory view of the manufacturing method of the toothed belt according to the eighth embodiment. FIG. 45 is a cross-sectional view showing an interface structure between the tooth portion side reinforcing cloth and the toothed belt body in the tenth embodiment. FIG. 46 is a cross-sectional view showing an interface structure between the tooth side reinforcing fabric and the toothed belt body in the eleventh embodiment. FIG. 47 is a diagram showing a pulley layout in a belt running test machine for evaluating tooth chipping resistance and wear resistance of a toothed belt.

Hereinafter, embodiments will be described with reference to the drawings.

[Embodiment 1]
<Rubber composition>
The rubber composition according to Embodiment 1 contains a rubber component and cellulosic fine fibers, and the fiber diameter distribution range of the cellulosic fine fibers includes 50 to 500 nm. The rubber composition may contain various rubber compounding agents in addition to the cellulosic fine fibers.

(Rubber component)
Examples of the rubber component of the rubber composition include ethylene-α-olefin elastomers (EPDM, EPR, etc.), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H-NBR), natural Examples thereof include rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), silicone rubber (Q), and fluorine rubber (FKM). Moreover, the blend rubber of 1 type, or 2 or more types of these may be sufficient.

(Cellulose fine fiber)
Cellulosic fine fibers are fiber materials derived from cellulose fine fibers composed of plant cell wall skeletal components obtained by finely loosening plant fibers. Examples of the cellulosic fine fiber plant include wood, bamboo, rice (rice straw), potato, sugar cane (bagasse), aquatic plants, and seaweed. Of these, wood is preferred. When the porous rubber composition forming the surface rubber layer 11a contains such cellulosic fine fibers, the high reinforcing effect is exhibited.

The cellulose-based fine fiber may be either the cellulose fine fiber itself or a hydrophobic cellulose fine fiber that has been subjected to a hydrophobic treatment. Moreover, you may use together cellulose fine fiber itself and hydrophobized cellulose fine fiber as a cellulosic fine fiber. From the viewpoint of dispersibility, the cellulosic fine fibers preferably include hydrophobized cellulose fine fibers. Examples of the hydrophobized cellulose fine fibers include cellulose fine fibers in which some or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups, and cellulose fine fibers that have been subjected to a hydrophobized surface treatment with a surface treatment agent.

Examples of hydrophobization for obtaining cellulose fine fibers in which part or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups include esterification (acylation) (alkyl esterification, complex esterification, β-ketoesterification, etc.) ), Alkylation, tosylation, epoxidation, arylation and the like. Of these, esterification is preferred. Specifically, in the esterified hydrophobized cellulose fine fiber, part or all of the hydroxyl groups of cellulose are carboxylic acids such as acetic acid, acetic anhydride, propionic acid, butyric acid, or halides thereof (particularly chlorides). It is the cellulose fine fiber acylated by. Examples of the surface treatment agent for obtaining cellulose fine fibers hydrophobized and surface-treated with the surface treatment agent include silane coupling agents.

Cellulosic fine fibers preferably have a wide fiber diameter distribution from the viewpoint of improving the stability of behavior under wet conditions, and the fiber diameter distribution range includes 50 to 500 nm. From the viewpoint, the lower limit of the fiber diameter distribution is preferably 50 nm or less, more preferably 20 nm or less, and still more preferably 10 nm or less. From the same viewpoint, the upper limit is preferably 500 nm or more, more preferably 700 nm or more, and further preferably 1 μn or more. The fiber diameter distribution range of the cellulosic fine fibers is preferably 50 to 500 nm, more preferably 20 nm to 700 mm, and more preferably 10 nm to 1 μm from the viewpoint of enhancing the reinforcing effect of the surface rubber layer 11a. Further preferred.

In addition, the average fiber diameter of the cellulosic fine fibers is preferably 10 nm or more, more preferably 30 nm or more, and preferably 1400 nm or less, more preferably, from the viewpoint of improving the stability of the behavior under wet conditions. 1000 nm or less, more preferably 800 nm or less.

The distribution of the fiber diameter of the cellulosic fine fibers is obtained by freezing and crushing a sample of the rubber composition, then observing the cross section with a transmission electron microscope (TEM) and arbitrarily selecting 50 cellulosic fine fibers. The fiber diameter is measured and obtained based on the measurement result. The average fiber diameter of the cellulosic fine fibers is obtained as the number average of the fiber diameters of 50 arbitrarily selected cellulosic fine fibers.

The cellulosic fine fibers may be either high aspect ratio manufactured by mechanical defibrating means, or needle-shaped crystals manufactured by chemical defibrating means. Moreover, you may use together what was manufactured by the mechanical defibration means, and what was manufactured by the chemical defibration means as a cellulose fine fiber. Examples of the defibrating apparatus used for the mechanical defibrating means include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a grinder, and a bead mill. Examples of the treatment used for the chemical defibrating means include acid hydrolysis treatment.

The content of the cellulosic fine fibers in the rubber composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still more preferably 5 parts by mass or more, with respect to 100 parts by mass of the rubber component. The amount is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and still more preferably 10 parts by mass or less.

(Rubber compounding agents other than cellulosic fine fibers)
Examples of the rubber compounding agent used in addition to the cellulosic fine fibers include a reinforcing material, oil, and a crosslinking agent.

As the reinforcing material, carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like.

The compounding amount of carbon black is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, and preferably 100 parts by mass or less, more preferably 80 parts per 100 parts by mass of the rubber component of the rubber composition. It is below mass parts.

Carbon black may have at least one of a hydroxyl group, a carbonyl group, and a carboxyl group.

Reinforcing agent also includes silica. Silica obtained by various production methods such as a sol-gel method, a wet method, and a dry method may be used. In particular, wet silica is preferred from the viewpoints of reinforcement and low heat build-up.

The amount of silica is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 30 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. Or less.

In addition, when silica is used, a silane coupling agent may be blended. Examples of the silane coupling agent include sulfide systems such as bis- (3- (triethoxysilyl) propyl) polysulfide (S number of polysulfide moiety: 2 to 8), mercapto systems such as 3-mercaptopropyltrimethoxysilane, 3- Examples include silane coupling agents used for ordinary rubbers of amino type such as aminopropyltrimethoxysilane and vinyl type such as vinyltriethoxysilane. A silane coupling agent may use only a single kind, and may mix and use multiple types. The addition amount of the silane coupling agent is preferably 0.5 to 15 parts by mass with respect to 100 parts by mass of the rubber component. When kneading using a supercritical fluid, which will be described later, an effect of further enhancing the interaction between the polymer and the filler can be obtained by adding a silane coupling agent.

Oils include, for example, petroleum-based softeners, mineral oils such as paraffin wax, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, fall raw oil, wax, rosin, pine And vegetable oils such as oil. The oil is preferably one or more of these. The oil content is, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the crosslinking agent include organic peroxides and sulfur. As a crosslinking agent, an organic peroxide may be blended, sulfur may be blended, or both of them may be used in combination. In the case of an organic peroxide, the amount of the crosslinking agent is, for example, 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. In the case of sulfur, the compounding amount is 100 parts by mass of the rubber component of the rubber composition. For example, 1 to 5 parts by mass.

(Manufacture of rubber composition)
In producing the rubber composition, first, cellulose fine fibers are introduced into the kneaded rubber component and dispersed by kneading.

Here, as a method for dispersing the cellulose-based fine fibers in the rubber component, for example, a dispersion (gel) in which the cellulose-based fine fibers are dispersed in water is added to the rubber component kneaded with an open roll, A method of vaporizing moisture while kneading them, a master of cellulose fine fibers / rubber obtained by mixing a dispersion (gel) in which cellulosic fine fibers are dispersed in water and rubber latex to vaporize the moisture Obtained by mixing the batch into a rubber component that has been masticated, mixing a dispersion in which cellulosic fine fibers are dispersed in a solvent, and a solution in which the rubber component is dissolved in the solvent, and evaporating the solvent. Cellulose fine fiber / rubber masterbatch is put into the kneaded rubber component, dispersion (gel) in which cellulose fine fiber is dispersed in water is freeze-dried and pulverized And what, how to put into a rubber component is masticated, methods and the like to introduce cellulosic microfibers made hydrophobic in rubber component is masticated.

Next, while kneading the rubber component and the cellulosic fine fiber, the various rubber compounding agents described above are added and kneading is continued. For this purpose, a kneader such as a kneader or a Banbury mixer can be used.

The uncrosslinked rubber composition obtained by the kneading process is molded and crosslinked by a normal molding and crosslinking process, whereby a crosslinked rubber composition is obtained.

For the forming and crosslinking step, for example, a press, a vulcanizer, a continuous vulcanizer, or the like may be used, or a special crosslinking group that is crosslinked by high-frequency crosslinking, radiation crosslinking, or electron beam crosslinking may be used.

The molding crosslinking conditions such as temperature, pressure, and time are appropriately set based on the composition of the filler-containing uncrosslinked rubber, the required quality of the rubber molded product, and the like. In the molding and crosslinking step, the polymer molecules contained in the uncrosslinked rubber composition are crosslinked with a crosslinking agent to form a network structure. Thereby, a crosslinked rubber composition is obtained.

Specific steps may be performed according to the type of rubber molded product to be manufactured. For example, when a wrapped V-belt as shown in FIG. 1 is manufactured, the following steps may be performed.

The wrapped V-belt B illustrated in FIG. 1 is used for, for example, an agricultural machine or an industrial machine, and the dimensions thereof are, for example, a belt circumferential length of 700 to 5000 mm, a belt width of 16 to 17 mm, and a belt thickness of 8 ~ 10 mm.

The wrapped V-belt B has a cross-sectional shape configured as a triple layer of a bottom rubber layer 11 on the belt inner peripheral side (pulley contact side), an intermediate adhesive rubber layer 12 and an extended rubber layer 13 on the belt outer peripheral side. A trapezoidal belt body 10 is provided. A core wire 14 is embedded in the adhesive rubber layer 12 so as to form a spiral having a pitch in the belt width direction. The belt body 10 is entirely covered with a reinforcing cloth 15.

The compressed rubber layer 11, the adhesive rubber layer 12, and the stretch rubber layer 13 are composed of a crosslinked rubber composition. And, at least one of the compressed rubber layer 11, the adhesive rubber layer 12, and the stretched rubber layer 13 is an uncrosslinked rubber composition in which a cellulosic fine fiber and various rubber compounding agents are blended and kneaded in a rubber component. The product is formed of a rubber composition that is heated and pressurized and crosslinked with a crosslinking agent.

The core wire 14 is composed of a wire such as a twisted yarn or a braid of polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, para-aramid fiber, vinylon fiber, or the like. In order to give the core wire 14 adhesion to the V-ribbed belt main body 10, an adhesive treatment that is heated after being immersed in an RFL aqueous solution before molding and / or an adhesive treatment that is dried after being immersed in rubber paste is performed. Before the said process, the adhesion | attachment process heated after being immersed in the adhesive agent solution which consists of solutions, such as an epoxy resin and a polyisocyanate resin, may be performed as needed. The outer diameter of the core wire 14 is, for example, 0.1 to 2 mm.

The reinforcing cloth 15 is made of, for example, a woven fabric, a knitted fabric, a non-woven fabric, or the like formed of yarns such as cotton, polyamide fiber, polyester fiber, and aramid fiber. In order to provide the adhesiveness to the belt main body 10, the reinforcing cloth 15 is coated with rubber paste on the surface on the side of the belt main body 10 and / or an adhesive treatment in which it is immersed in an RFL aqueous solution and heated before molding. Adhesive treatment for drying is applied.

Next, a manufacturing method of the wrapped V-belt B according to the first embodiment will be described with reference to FIGS.

First, a rubber sheet 11 ′ for the compression rubber layer, a rubber sheet 12 ′ for the adhesive rubber layer, a rubber sheet 13 ′ for the stretch rubber layer, a twisted yarn 14 ′ for the core wire, and a cloth 15 ′ for the reinforcing cloth prepare. At this time, among the rubber sheet 11 ′ for the compression rubber layer, the rubber sheet 12 ′ for the adhesive rubber layer, and the rubber sheet 13 ′ for the stretch rubber layer, those including the recycled rubber according to the first embodiment are the first embodiment. An uncrosslinked rubber composition obtained by kneading the recycled rubber and the rubber compounding agent is obtained by processing into a sheet shape using a calender roll or the like. Further, the twisted yarn 14 ′ for the core wire and the fabric 15 ′ for the reinforcing fabric are subjected to adhesion treatment.

Next, as shown in FIG. 2 (a), the rubber sheet 11 'for the compression rubber layer is wound around the mantle 21 a plurality of times, and the rubber sheet 12' for the adhesive rubber layer is wound thereon. On top of that, as shown in FIG. 2 (b), the twisted yarn 14 'is wound spirally. Furthermore, as shown in FIG. 2 (c), a rubber sheet 12 'for the adhesive rubber layer and a rubber sheet 13' for the stretch rubber layer are wound in order to produce a cylindrical laminated structure 10 '.

Next, as shown in FIG. 2 (d), the cylindrical laminated structure 10 ′ is cut into a predetermined width on the mantle 21 and then removed from the mantle 21.

Next, as shown in FIG. 2 (e), the annular laminated structure 10 ′ is rotated while being wound around a pair of pulleys with the rubber sheet 11 ′ side for the compressed rubber layer facing outward. The volume is adjusted by obliquely cutting both sides of the laminated portion of the rubber sheet 11 'for use in a V shape.

Subsequently, as shown in FIG. 2 (f), the outer periphery of the annular laminated structure 10 ′ is covered with a cloth 15 ′.

Then, as shown in FIG. 2 (g), the lapped annular laminated structure 10 'is fitted into the groove 23 of the cylindrical mold 22, and it is placed in a vulcanizing can and heated and pressurized. At this time, the rubber component of the annular laminated structure 10 ′ is cross-linked to form the belt main body 10, and the twisted yarn 14 ′ is bonded and integrated to the belt main body 10 to form the core wire 14, and the cloth 15 ′ is the belt main body. The wrapped V-belt B according to the first embodiment is manufactured by being bonded and integrated with 10 to form the reinforcing cloth 15.

The rubber composition of the present invention can be used for various parts and products such as transmission belts such as V-ribbed belts, toothed belts, flat belts, conveyor belts, tires, etc. in addition to V-belts.

The rubber composition of Example 1 will be described below. Each example is also described in Table 1.

<Example 1-1>
First, a dispersion in which powdered cellulose (trade name: KC Flock W-GK manufactured by Nippon Paper Industries Co., Ltd.) is dispersed in toluene is prepared, and the dispersion is collided with a high-pressure homogenizer to convert the powdered cellulose into cellulose fine fibers. The fiber was defibrated to obtain a dispersion in which cellulose fine fibers were dispersed in toluene. Accordingly, the cellulose fine fibers are produced by mechanical defibrating means and are not subjected to a hydrophobic treatment.

Next, the dispersion in which fine cellulose fibers are dispersed in toluene, and H-NBR (trade name: Zetpol 2020 manufactured by Nippon Zeon Co., Ltd.) are dissolved in toluene and a plasticizer (trade name: W-260 manufactured by DIC) is added. The resultant solution was mixed, and toluene and a plasticizer were vaporized to prepare a master batch of cellulose fine fiber / H-NBR. The content of each component in the master batch was 25% by mass for the cellulosic fine fibers, 25% by mass for the plasticizer, and 50% by mass for H-NBR.

Subsequently, EPDM was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the content of cellulosic fine fibers was 5 parts by mass with respect to 100 parts by mass of total EPDM.

Then, EPDM and cellulose fine fibers are kneaded, and 30 parts by mass of reinforcing material carbon black FEF (manufactured by Tokai Carbon Co., Ltd., trade name: Seast SO) is added to 100 parts by mass of EPDM. 8 parts by mass of Petroleum Co., Ltd., trade name: Thumper 2280) and 5 parts by mass of cross-linking agent (trade name: Peroximon F-40, manufactured by NOF Corporation) are added to each other to continue kneading, thereby uncrosslinked rubber composition A product was made.

<Example 1-2>
In the same manner as in Example 1-1, a cellulosic fine fiber / EPDM master batch was produced. Subsequently, EPDM was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the content of cellulosic fine fibers was 5 parts by mass with respect to 100 parts by mass of total EPDM.

And while kneading | mixing EPDM and a cellulose fine fiber, there are 30 mass parts of carbon black FEF as a reinforcing material and 10 masses of silica (Degussa, trade name: Ultrazil VN3) with respect to 100 mass parts of EPDM. Then, 8 parts by mass of oil and 5 parts by mass of oil and 5 parts by mass of the crosslinking agent were added and kneading was continued to prepare an uncrosslinked rubber composition. That is, 10 parts by mass of silica is further added to the formulation of Example 1-1.

<Example 1-3>
In the same manner as in Example 1-1, a cellulosic fine fiber / EPDM master batch was produced. Subsequently, EPDM was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the content of cellulosic fine fibers was 5 parts by mass with respect to 100 parts by mass of total EPDM.

And while knead | mixing EPDM and a cellulosic fine fiber, with respect to 100 mass parts of EPDM, 8 mass parts of oil and 5 mass parts of crosslinking agents are respectively added, and kneading is continued, and an uncrosslinked rubber composition is obtained. Produced. Compared with Example 1-1, the formulation does not contain carbon black.

<Example 1-4>
In the same manner as in Example 1-1, a cellulosic fine fiber / EPDM master batch was produced. Subsequently, EPDM was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the content of the cellulosic fine fibers was 10 parts by mass with respect to 100 parts by mass of the total EPDM.

And while knead | mixing EPDM and a cellulosic fine fiber, with respect to 100 mass parts of EPDM, 8 mass parts of oil and 5 mass parts of crosslinking agents are respectively added, and kneading is continued, and an uncrosslinked rubber composition is obtained. Produced. Compared to Example 1-1, the blended amount of the cellulosic fine fibers is 5 parts by mass and does not contain carbon black.

<Comparative Example 1-1>
EPDM was masticated, and 8 parts by mass of oil and 5 parts by mass of a crosslinking agent were added to 100 parts by mass of EPDM, and kneading was continued to prepare an uncrosslinked rubber composition. Compared to Example 1-1, the blend was free of cellulosic fine fibers and carbon black.

<Comparative Example 1-2>
While EPDM is masticated, 30 parts by mass of carbon black FEF as a reinforcing material, 8 parts by mass of oil, and 5 parts by mass of a crosslinking agent are added to 100 parts by mass of EPDM, and then kneading is continued to be uncrosslinked. A rubber composition was prepared. Compared to Example 1-1, the formulation does not contain cellulosic fine fibers.

(Test evaluation method)
<Average fiber diameter / fiber diameter distribution>
Samples collected from the rubber compositions cross-linked by press molding in Examples 1-1 to 1-4 were freeze-ground, and the cross-section was observed with a scanning electron microscope (SEM). Fibers were arbitrarily selected and the fiber diameter was measured, and the number average was obtained to obtain the average fiber diameter. Moreover, the maximum value and minimum value of the fiber diameter were calculated | required among 50 cellulose fine fibers.

<Abrasion resistance and friction coefficient evaluation test>
For each of Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-2, test pieces of rubber compositions crosslinked by press molding were prepared. The dimensions of the test piece are 5 mm square and 10 mm long.

First, the initial mass of the test piece was measured. Thereafter, using a pin-on-disk type friction and wear tester, the surface of a 5 mm square surface of the test piece was brought into contact with the surface of a disk-shaped counterpart made of gray cast iron (FC200). A pressure of 0.8 MPa was applied to the test piece from above, the mating member was rotated so that the sliding speed was 0.25 m / sec, and the mass of the test piece after 4 hours was measured. The change from the initial mass was defined as the wear mass. Table 1 shows values that are ten times the wear mass in mg.

This measurement was performed in a dry state. The temperature of the counterpart material was set to 60 ° C.

In the same manner as described above, a 5 mm square surface of the test piece is used as a sliding surface and brought into contact with the surface of a counterpart material made of gray cast iron. The friction coefficient was measured by rotating the mating member so that the force was 0.25 m / sec and measuring the force.

Such measurement of the coefficient of friction was carried out when dry, wet and dry. The time of drying is a state in which the test piece and the counterpart material are sufficiently dried. In the wet state, water is dropped on the surface of the disk-shaped mating material, and water is also present between the test piece and the mating material. Moreover, after stopping dripping of water from a wet state, a peak occurs in the coefficient of friction during drying. Drying means the time when such a peak occurs.

(Test evaluation results)
The test results are shown in Table 1.

According to Table 1, it can be seen that all of the fine cellulose fibers of Examples 1-1 to 1-4 have a wide fiber diameter distribution. In addition, Example 1-1 and Example 1-2 in which cellulose fine fibers and carbon black are used in combination use Examples 1-3 and Example 1-4 in which cellulose fine fibers are used but carbon black is not used. Is smaller than the average fiber diameter. In Example 1-2 using silica, the average, maximum and minimum fiber diameters are all smaller than in Example 1-1 using no silica.

Further, in Example 1-1 and Example 1-2, no agglomerates having a diameter of 5 μm or more of the cellulosic fine fibers were observed, whereas the presence was confirmed in Examples 1-3 and 1-4. Is done. That is, in Example 1-1 and Example 1-2, the dispersibility of the cellulosic fine fibers is superior to that of Example 1-3 and Example 1-4.

The amount of wear is 798 in Comparative Example 1-1 which does not contain cellulosic fine fibers and carbon black. On the other hand, in Comparative Example 1-2 containing only carbon black, it is 174, and in Examples 1-3 and 1-4 using only cellulose-based fine fibers, it is 198 and 163. Therefore, the cellulose-based fine fibers can achieve the same wear resistance as that of carbon black. In Example 1-1 in which cellulosic fine fibers and carbon black are used in combination as reinforcing materials, it is 86, and in Example 1-2 in which silica is used, it is 94. Further, the abrasion resistance of the rubber composition is further improved.

Looking at the friction coefficient, in the case of Example 1-1 and Example 1-2, the variation in the value at the time of drying, wetting and drying is 0.1. On the other hand, in Comparative Examples 1 and 2 that do not use cellulosic fine fibers, the friction coefficient greatly decreases when wet, and increases when dry, and the fluctuations are large (in order 1.2 and 1). .1). In Example 1-3 and Example 1-4 using cellulosic fine fibers, the range of variation is 0.2, although it is larger than that in Example 1-1 and Example 1-2. This is a marked improvement over Example 1-1 and Comparative Example 1-2.

Thus, by blending together the cellulosic fine fibers and carbon black, it is possible to obtain a rubber composition having a small variation in friction coefficient under conditions where water exposure and drying occur. Accordingly, the rubber part made of such a rubber composition has a stable behavior under wet conditions.

As described above, by using cellulosic fine fibers as the reinforcing material of the rubber composition, and further using carbon black together, it is possible to obtain a rubber part having high wear resistance and stable behavior under wet conditions.

[Embodiment 2]
(V-ribbed belt B)
3 and 4 show a V-ribbed belt B according to the second embodiment. The V-ribbed belt B according to the second embodiment is an endless power transmission member used, for example, in an accessory drive belt transmission device provided in an engine room of an automobile. The V-ribbed belt B according to Embodiment 2 has, for example, a belt length of 700 to 3000 mm, a belt width of 10 to 36 mm, and a belt thickness of 4.0 to 5.0 mm.

The V-ribbed belt B according to the second embodiment has a three-layer structure including a compression rubber layer 111 that constitutes a pulley contact portion on the belt inner peripheral side, an intermediate adhesive rubber layer 112, and a back rubber layer 113 on the belt outer peripheral side. A rubber V-ribbed belt main body 110 is provided. A core wire 114 is embedded in an intermediate portion in the thickness direction of the adhesive rubber layer 112 in the V-ribbed belt main body 110 so as to form a spiral having a pitch in the belt width direction. A back reinforcing cloth may be provided instead of the back rubber layer 113, and the V-ribbed belt main body 110 may be configured as a double layer of the compression rubber layer 111 and the adhesive rubber layer 112.

The compression rubber layer 111 is provided such that a plurality of V ribs 115 hang down to the belt inner peripheral side. The plurality of V ribs 115 are each formed in a ridge having a substantially inverted triangular cross section extending in the belt length direction, and provided in parallel in the belt width direction. Each V-rib 115 has, for example, a rib height of 2.0 to 3.0 mm and a width between base ends of 1.0 to 3.6 mm. The number of V ribs 115 is, for example, 3 to 6 (6 in FIG. 3). The adhesive rubber layer 112 is formed in a strip shape having a horizontally long cross section, and has a thickness of, for example, 1.0 to 2.5 mm. The back rubber layer 113 is also formed in a band shape having a horizontally long cross section, and has a thickness of, for example, 0.4 to 0.8 mm. It is preferable that a woven fabric pattern is provided on the surface of the back rubber layer 113 from the viewpoint of suppressing sound generation during back driving.

The compressed rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 are rubbers obtained by crosslinking an uncrosslinked rubber composition obtained by mixing and kneading various rubber compounding ingredients with a rubber component and then crosslinking with a crosslinking agent. It is formed with a composition. The rubber composition forming the compressed rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 may be the same or different.

Examples of the rubber component of the rubber composition forming the compression rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 include ethylene / propylene copolymer (EPR), ethylene / propylene / diene terpolymer (EPDM), Examples include ethylene-α-olefin elastomers such as octene copolymer and ethylene / butene copolymer; chloroprene rubber (CR); chlorosulfonated polyethylene rubber (CSM); hydrogenated acrylonitrile rubber (H-NBR). The rubber component is preferably one or more of these blend rubbers. The rubber components of the rubber composition forming the compression rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 are preferably the same.

At least one of the rubber compositions forming the compressed rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. It is preferable that all the rubber compositions forming the compressed rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 contain such cellulosic fine fibers, but at least the compressed rubber layer 111 constituting the pulley contact portion is formed. It is more preferable that the rubber composition to be contained contains such cellulosic fine fibers.

According to the V-ribbed belt B according to the second embodiment, at least one of the rubber compositions forming the compression rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 constituting the V-ribbed belt main body 110 is a fiber. By containing a cellulosic fine fiber having a diameter distribution range of 50 to 500 nm, excellent bending fatigue resistance can be obtained. Moreover, when the rubber composition which forms the compression rubber layer 111 which comprises a contact part contains such a cellulose fine fiber, a stable friction coefficient can be obtained with high abrasion resistance.

Cellulosic fine fiber is a fiber material derived from cellulose fine fiber composed of a skeletal component of a plant cell wall obtained by finely loosening plant fiber. Examples of the cellulosic fine fiber plant include wood, bamboo, rice (rice straw), potato, sugar cane (bagasse), aquatic plants, seaweed and the like. Of these, wood is preferred.

The cellulose-based fine fiber may be either the cellulose fine fiber itself or a hydrophobic cellulose fine fiber that has been subjected to a hydrophobic treatment. Moreover, you may use together cellulose fine fiber itself and hydrophobized cellulose fine fiber as a cellulosic fine fiber. From the viewpoint of dispersibility, the cellulosic fine fibers preferably include hydrophobized cellulose fine fibers. Examples of the hydrophobized cellulose fine fibers include cellulose fine fibers in which some or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups, and cellulose fine fibers that have been subjected to a hydrophobized surface treatment with a surface treatment agent.

Examples of hydrophobization for obtaining cellulose fine fibers in which part or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups include esterification (acylation) (alkyl esterification, complex esterification, β-ketoesterification, etc.) ), Alkylation, tosylation, epoxidation, arylation and the like. Of these, esterification is preferred. Specifically, in the esterified hydrophobized cellulose fine fiber, part or all of the hydroxyl groups of cellulose are carboxylic acids such as acetic acid, acetic anhydride, propionic acid, butyric acid, or halides thereof (particularly chlorides). It is the cellulose fine fiber acylated by. Examples of the surface treatment agent for obtaining cellulose fine fibers hydrophobized and surface-treated with the surface treatment agent include silane coupling agents.

The cellulosic fine fibers preferably have a wide fiber diameter distribution from the viewpoint of enhancing bending fatigue resistance, and the fiber diameter distribution range includes 50 to 500 nm. From the viewpoint, the lower limit of the fiber diameter distribution is preferably 20 nm or less, more preferably 10 nm or less. From the same viewpoint, the upper limit is preferably 700 nm or more, more preferably 1 μm or more. The fiber diameter distribution range of the cellulosic fine fibers preferably includes 20 nm to 700 mm, and more preferably includes 10 nm to 1 μm.

The average fiber diameter of the cellulosic fine fibers contained in the rubber composition is preferably 10 nm or more, more preferably 20 nm or more, and preferably 700 nm or less, more preferably 100 nm or less.

The distribution of the fiber diameter of the cellulosic fine fibers is obtained by freezing and crushing a sample of the rubber composition, then observing the cross section with a transmission electron microscope (TEM) and arbitrarily selecting 50 cellulosic fine fibers. The fiber diameter is measured and obtained based on the measurement result. The average fiber diameter of the cellulosic fine fibers is obtained as the number average of the fiber diameters of 50 arbitrarily selected cellulosic fine fibers.

The cellulosic fine fibers may be either high aspect ratio manufactured by mechanical defibrating means, or needle-shaped crystals manufactured by chemical defibrating means. Of these, those manufactured by mechanical defibrating means are preferred. Moreover, you may use together what was manufactured by the mechanical defibration means, and what was manufactured by the chemical defibration means as a cellulose fine fiber. Examples of the defibrating apparatus used for the mechanical defibrating means include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a grinder, and a bead mill. Examples of the treatment used for the chemical defibrating means include acid hydrolysis treatment.

The content of the cellulosic fine fibers in the rubber composition is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts with respect to 100 parts by mass of the rubber component from the viewpoint of enhancing the bending fatigue resistance. It is not less than 30 parts by mass, preferably not more than 30 parts by mass, more preferably not more than 20 parts by mass, and still more preferably not more than 10 parts by mass.

Examples of rubber compounding agents include reinforcing materials, process oils, processing aids, vulcanization acceleration aids, crosslinking agents, vulcanization accelerators, and anti-aging agents.

As the reinforcing material, carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like. Silica is also mentioned as the reinforcing material. It is preferable that a reinforcing material is 1 type, or 2 or more types among these. The content of the reinforcing material is preferably 50 to 90 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Oils include, for example, petroleum-based softeners, mineral oils such as paraffin wax, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, fall raw oil, wax, rosin, pine And vegetable oils such as oil. The oil is preferably one or more of these. The oil content is, for example, 10 to 30 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of processing aids include stearic acid, polyethylene wax, and fatty acid metal salts. Among these, the processing aid is preferably one or more. The content of the processing aid is, for example, 0.5 to 2 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the vulcanization acceleration aid include metal oxides such as magnesium oxide and zinc oxide (zinc white), metal carbonates, fatty acids and derivatives thereof. Among these, the vulcanization acceleration aid is preferably one or more. The content of the vulcanization acceleration aid is, for example, 3 to 7 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the anti-aging agent include benzimidazole anti-aging agents, amine-ketone anti-aging agents, diamine anti-aging agents, and phenol anti-aging agents. It is preferable that an anti-aging agent is 1 type, or 2 or more types among these. The content of the anti-aging agent is, for example, 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the co-crosslinking agent include maleimide, TAIC, 1,2-polybutadiene, oximes, guanidine, trimethylolpropane trimethacrylate, and liquid rubber. The co-crosslinking agent is preferably one or more of these. The content of the co-crosslinking agent is, for example, 0.5 to 30 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be blended, an organic peroxide may be blended, or both of them may be used in combination. The amount of the crosslinking agent is, for example, 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, and 100 parts by mass of the rubber component of the rubber composition with respect to the organic peroxide. For example, 1 to 5 parts by mass.

Examples of the vulcanization accelerator include thiuram (eg, TETD, TT, TRA, etc.), thiazole (eg, MBT, MBTS, etc.), sulfenamide (eg, CZ), dithiocarbamate (eg, BZ-P). Etc.). It is preferable that a vulcanization accelerator is 1 type, or 2 or more types among these. The content of the vulcanization accelerator is, for example, 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

The rubber composition forming the compressed rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 may contain short fibers 116 having a fiber diameter of 10 μm or more. In particular, it is preferable that the short fiber 116 is contained in the rubber composition forming the compressed rubber layer 111 constituting the pulley contact portion. In that case, the short fibers 116 are preferably contained in the compressed rubber layer 111 so as to be oriented in the belt width direction, and a part of the short fibers 116 exposed on the surface of the V rib 115 of the compressed rubber layer 111 is a part. Preferably protrudes from the surface. In addition, the structure by which the short fiber 116 was not planted in the rubber composition, and the short fiber was planted on the V rib 115 surface of the compressed rubber layer 111 may be used.

Examples of the short fibers 116 include nylon short fibers, vinylon short fibers, aramid short fibers, polyester short fibers, and cotton short fibers. The short fiber 116 is manufactured by, for example, cutting a long fiber that has been subjected to an adhesive treatment to be heated after being immersed in an RFL aqueous solution or the like into a predetermined length. The length of the short fiber 116 is, for example, 0.2 to 5.0 mm, and the fiber diameter is, for example, 10 to 50 μm.

The content of the short fibers 116 is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, with respect to 100 parts by mass of the rubber component. It is. The content of the short fibers 116 is preferably larger than the content of the cellulosic fine fibers. The ratio of the content of the short fibers 116 to the content of the cellulosic fine fibers (the content of the cellulosic fine fibers of the content of the short fibers 116) is preferably 1 or more, more preferably 2 or more, and preferably Is 15 or less, more preferably 5 or less. The total content of cellulosic fine fibers and short fibers 116 is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 25 parts by mass or less, with respect to 100 parts by mass of the rubber component. Preferably it is 15 mass parts or less.

The core wire 114 is composed of a twisted yarn formed of polyamide fiber, polyester fiber, aramid fiber, polyamide fiber or the like. The diameter of the core wire 114 is, for example, 0.5 to 2.5 mm, and the dimension between the centers of adjacent core wires 114 in the cross section is, for example, 0.05 to 0.20 mm. The core wire 114 is subjected to an adhesive treatment for imparting adhesiveness to the V-ribbed belt main body 110.

FIG. 5 shows a pulley layout of an auxiliary drive belt transmission device 190 for an automobile using the V-ribbed belt B according to the second embodiment. The accessory drive belt transmission device 190 is of a serpentine drive type in which a V-ribbed belt B is wound around six pulleys of four rib pulleys and two flat pulleys to transmit power.

In this accessory drive belt transmission device 190, a power steering pulley 191 of a rib pulley is provided at the uppermost position, and an AC generator pulley 192 of a rib pulley is provided below the power steering pulley 191. A flat pulley tensioner pulley 193 is provided on the lower left side of the power steering pulley 191, and a flat pulley water pump pulley 194 is provided on the lower side of the tensioner pulley 193. Further, a rib pulley crankshaft pulley 195 is provided on the lower left side of the tensioner pulley 193, and a rib pulley air conditioner pulley 196 is provided on the lower right side of the crankshaft pulley 195. These pulleys are made of, for example, a metal stamped product, a casting, or a resin molded product such as nylon resin or phenol resin, and have a pulley diameter of φ50 to 150 mm.

In this accessory drive belt transmission device 190, the V-ribbed belt B is wound around the power steering pulley 191 so that the V-rib 115 side contacts, and then wound around the tensioner pulley 193 so that the back surface of the belt contacts. After that, it is wound around the crankshaft pulley 195 and the air conditioner pulley 196 in order so that the V-rib 115 side contacts, and further wound around the water pump pulley 194 so that the back surface of the belt contacts, and the V-rib 115 side contacts. Thus, it is wound around the AC generator pulley 192 and finally returned to the power steering pulley 191. The belt span length, which is the length of the V-ribbed belt B spanned between the pulleys, is, for example, 50 to 300 mm. Misalignment that can occur between pulleys is 0-2 °.

(Manufacturing method of V-ribbed belt B)
A method for manufacturing the V-ribbed belt B according to the second embodiment will be described with reference to FIGS. 6, 7, 8, and 9.

6 and 7 show a belt mold 130 used for manufacturing the V-ribbed belt B according to the second embodiment.

The belt mold 130 includes a cylindrical inner mold 131 and an outer mold 132, which are provided concentrically.

The inner mold 131 is made of a flexible material such as rubber. The outer mold 132 is made of a rigid material such as metal. The inner peripheral surface of the outer mold 132 is formed as a molding surface, and V rib forming grooves 133 having the same shape as the V rib 115 are provided on the inner peripheral surface of the outer mold 132 at a constant pitch in the axial direction. Yes. The outer mold 132 is provided with a temperature control mechanism that controls the temperature by circulating a heat medium such as water vapor or a coolant such as water. Further, a pressurizing means for pressurizing and expanding the inner mold 131 from the inside is provided.

The manufacturing method of the V-ribbed belt B according to Embodiment 2 includes a material preparation process, a molding process, a crosslinking process, and a finishing process.

<Material preparation process>
-Uncrosslinked rubber sheets 111 ', 112', 113 'for compressed rubber layer, adhesive rubber layer, and back rubber layer
Of the uncrosslinked rubber sheets 111 ′, 112 ′, and 113 ′ for the compressed rubber layer, the adhesive rubber layer, and the back rubber layer, those containing cellulosic fine fibers are produced as follows.

First, cellulosic fine fibers are put into a kneaded rubber component and dispersed by kneading.

Here, as a method for dispersing the cellulose-based fine fibers in the rubber component, for example, a dispersion (gel) in which the cellulose-based fine fibers are dispersed in water is added to the rubber component kneaded with an open roll, A method of vaporizing moisture while kneading them, a master of cellulose fine fibers / rubber obtained by mixing a dispersion (gel) in which cellulosic fine fibers are dispersed in water and rubber latex to vaporize the moisture Obtained by mixing the batch into a rubber component that has been masticated, mixing a dispersion in which cellulosic fine fibers are dispersed in a solvent and a solution in which the rubber component is dissolved in the solvent, and evaporating the solvent Cellulose fine fiber / rubber masterbatch is put into the kneaded rubber component, dispersion (gel) in which cellulose fine fiber is dispersed in water is freeze-dried and pulverized And what, how to put into a rubber component is masticated, methods and the like to introduce cellulosic microfibers made hydrophobic in rubber component is masticated.

Next, while kneading the rubber component and the cellulosic fine fiber, various rubber compounding agents are added and kneading is continued to prepare an uncrosslinked rubber composition.

Then, the uncrosslinked rubber composition is molded into a sheet by calendar molding or the like.

In addition, the preparation of those not containing cellulosic fine fibers is carried out by blending various rubber compounding agents with the rubber component, kneading with a kneader such as a kneader or a Banbury mixer, and the resulting uncrosslinked rubber composition by calendar molding or the like. This is done by forming into a sheet.

-Core 114'-
An adhesive treatment is applied to the core wire 114 '. Specifically, the core wire 114 'is subjected to an RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated. Moreover, it is preferable to perform the foundation | substrate adhesion | attachment process which immerses in a foundation | substrate adhesion | attachment processing liquid and heats before RFL adhesion | attachment processing. In addition, you may give the rubber paste adhesion | attachment process which is immersed in rubber glue and dried before RFL adhesion | attachment processing.

<Molding process>
As shown in FIG. 8, a rubber sleeve 135 is placed on a cylindrical drum 134 having a smooth surface, and an uncrosslinked rubber sheet 113 ′ for the back rubber layer and an uncrosslinked rubber sheet 112 for the adhesive rubber layer are formed on the outer periphery thereof. 'Are wound in order and laminated, and the core wire 114' is wound spirally around the cylindrical inner mold 131 from above, and further, an uncrosslinked rubber sheet 112 'for the adhesive rubber layer and a compressed rubber layer are further formed thereon. The uncrosslinked rubber sheet 111 ′ is wound in order. At this time, a laminated molded body B ′ is formed on the rubber sleeve 135.

<Crosslinking process>
The rubber sleeve 135 provided with the laminated molded body B ′ is removed from the cylindrical drum 134 and, as shown in FIG. 9, it is set in the inner peripheral surface side of the outer mold 132, and then as shown in FIG. 10. The inner mold 131 is positioned and sealed in the rubber sleeve 135 set on the outer mold 132.

Next, the outer mold 132 is heated and pressurized by injecting high-pressure air or the like into the sealed interior of the inner mold 131. At this time, the inner mold 131 expands, and the uncrosslinked rubber sheets 111 ′, 112 ′, 113 ′ in the laminated molded body B ′ enter the molded surface of the outer mold 132 while being compressed, and the crosslinking proceeds. In addition, the core wire 114 ′ is combined and integrated, and finally, a cylindrical belt slab S is formed as shown in FIG. The molding temperature of the belt slab S is, for example, 100 to 180 ° C., the molding pressure is, for example, 0.5 to 2.0 MPa, and the molding time is, for example, 10 to 60 minutes.

<Finishing process>
The inside of the inner mold 131 is decompressed to release the seal, the belt slab S molded between the inner mold 131 and the outer mold 132 is taken out via the rubber sleeve 135, and the belt slab S is cut into a predetermined width and turned upside down. V-ribbed belt B is manufactured by turning over.

[V-ribbed belt]
V-ribbed belts of Examples 2-1 to 2-9 and Comparative Example 2 below were produced. Details of each are also shown in Table 2.

<Example 2-1>
Prepare a dispersion in which powdered cellulose (trade name: KC Flock W-50GK, manufactured by Nippon Paper Industries Co., Ltd.) made of wood as a raw material in toluene is dispersed. The fine fibers were defibrated to obtain a dispersion in which cellulose fine fibers were dispersed in toluene. Accordingly, the cellulose fine fibers are produced by mechanical defibrating means and are not subjected to a hydrophobic treatment.

Next, the dispersion in which cellulose fine fibers are dispersed in toluene is mixed with a solution in which ethylene propylene diene monomer (trade name: EP33, manufactured by JSR Corporation, hereinafter referred to as “EPDM”) is dissolved in toluene, and the toluene is vaporized. Thus, a master batch of cellulose fine fiber / EPDM was prepared.

Subsequently, EPDM was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the cellulose fine fiber content was 1 part by mass when the total EPDM was 100 parts by mass.

Then, EPDM and fine cellulose fibers are kneaded, and 60 mass parts of HAF carbon black (trade name: Dia Black H) manufactured by Mitsubishi Chemical Co., Ltd. is added to 100 mass parts of EPDM. Name: 15 parts by weight of sampler 2280), 1 part by weight of stearic acid (manufactured by Shin Nippon Rika Co., Ltd., trade name: stearic acid 50S) as processing aid, zinc oxide (product of Sakai Chemical Co., Ltd.) as vulcanization accelerator Name: 5 parts by mass of zinc oxide (3 types), 2.5 parts by mass of benzimidazole anti-aging agent (trade name: NOCRACK MB), sulfur as a crosslinking agent (product by Hosoi Chemical Co., Ltd.) Name: oil sulfur) 2.3 parts by mass, and thiuram vulcanization accelerator (made by Ouchi Shinsei Chemical Co., Ltd., trade name: Noxeller TET-G) To prepare uncrosslinked rubber composition by continuing kneading the.

Using this uncrosslinked rubber composition, a V-ribbed belt of Example 2-1 having the same configuration as that of Embodiment 2 in which a compressed rubber layer was formed so that the cutting direction was the belt width direction was produced.

The V-ribbed belt of Example 2-1 had a belt length of 1400 mm, a belt width of 2.2 mm, a belt thickness of 4.5 mm, and three V-ribs. The adhesive rubber layer and the back rubber layer were formed from a rubber composition not containing cellulose fine fibers and short fibers, and the core wire was formed from a polyester fiber twisted yarn that had been subjected to an adhesive treatment.

<Example 2-2>
A V-ribbed belt of Example 2-2 was produced in the same manner as Example 2-1 except that the content of cellulose fine fibers was 3 parts by weight with respect to 100 parts by weight of the rubber component.

<Example 2-3>
A V-ribbed belt of Example 2-3 was produced in the same manner as Example 2-1 except that the content of the fine cellulose fiber was 5 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 2-4>
A V-ribbed belt of Example 2-4 was produced in the same manner as Example 2-1 except that the content of cellulose fine fibers was 10 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 2-5>
A V-ribbed belt of Example 2-5 was produced in the same manner as Example 2-1 except that the content of cellulose fine fiber was 15 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 2-6>
A V-ribbed belt of Example 2-6 was produced in the same manner as Example 2-1 except that the content of cellulose fine fiber was 25 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 2-7>
Except that the uncrosslinked rubber composition for the compression rubber layer contains 14 parts by mass of nylon short fibers (trade name: CFN3000, fiber diameter: 26 μm, fiber length: 3 mm, manufactured by Teijin Ltd.) with respect to 100 parts by mass of the rubber component. In the same manner as in Example 2-1, a V-ribbed belt of Example 2-7 was produced. The ratio of the short fiber content to the cellulosic fine fiber content (“B / A” in Table 2) is 14. The total content of cellulosic fine fibers and short fibers ("A + B" in Table 2) is 15 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 2-8>
The V of Example 2-8 is the same as Example 2-2 except that the uncrosslinked rubber composition for the compressed rubber layer contains 12 parts by mass of nylon short fibers with respect to 100 parts by mass of the rubber component. A ribbed belt was produced. The ratio (B / A) of the short fiber content to the cellulosic fine fiber content is 4. The total content (A + B) of the cellulosic fine fibers and short fibers is 15 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 2-9>
The V of Example 2-9 is the same as Example 2-3 except that the uncrosslinked rubber composition for the compressed rubber layer contains 10 parts by mass of nylon short fibers per 100 parts by mass of the rubber component. A ribbed belt was produced. The ratio of the short fiber content to the cellulosic fine fiber content (the short fiber content to the cellulosic fine fiber content) is 3. The total content of cellulosic fine fibers and short fibers is 15 parts by mass with respect to 100 parts by mass of the rubber component.

<Comparative example 2>
The same as Example 2-1 except that the uncrosslinked rubber composition for the compressed rubber layer does not contain fine cellulose fibers and 15 parts by mass of nylon short fibers per 100 parts by mass of the rubber component. Thus, a V-ribbed belt of Comparative Example 2 was produced.

(Test evaluation method)
<Average fiber diameter / fiber diameter distribution>
Samples collected for the rubber compositions forming the compressed rubber layers of the V-ribbed belts of Examples 2-1 to 2-9 were freeze-ground and the cross sections thereof were observed with a scanning electron microscope (SEM). , 50 fibers were arbitrarily selected, the fiber diameter was measured, and the number average was obtained to obtain the average fiber diameter. Moreover, the maximum value and minimum value of the fiber diameter were calculated | required among 50 cellulose fine fibers.

<Friction coefficient measurement test>
FIG. 16 shows a friction coefficient measuring device 140.

The friction coefficient measuring device 140 includes a test pulley 141 made of a rib pulley having a pulley diameter of 75 mm and a load cell 142 provided on the side thereof. The test pulley 141 is made of an iron-based material S45C. The test piece 143 of the V-ribbed belt extends horizontally from the load cell 142 and is then wound around the test pulley 141. That is, the V-ribbed belt test piece 143 is provided such that the winding angle around the test pulley 141 is 90 °.

About each V-ribbed belt of Example 2-1 to Example 2-9 and Comparative Example 2, a belt-shaped test piece 143 is cut and fixed at one end to the load cell 142 and wound around the test pulley 141. A weight 144 was attached to the other end and hung. Subsequently, at an ambient temperature of 25 ° C., the test pulley 141 is rotated at a rotation speed of 43 rpm in a direction to lower the weight 144, and at 60 seconds after the rotation starts, the test pulley 141 in the test piece 143 is loaded by the load cell 142. The tension Tt applied to the horizontal portion between the load cell 142 and the load cell 142 was measured. The tension Ts applied to the vertical part of the test pulley 141 and the weight 144 of the test piece 143 was 17.15 N corresponding to the weight of the weight 144. Then, the friction coefficient μ at the time of drying the surface of the compressed rubber layer was obtained by the following formula (1) based on the Euler formula. Note that θ = π / 2.

Also, water was interposed on the test pulley 141, the same test was carried out when it was dried, and the difference obtained by subtracting the friction coefficient at the time of drying from the friction coefficient at the time of drying was obtained.

<Abrasion resistance evaluation belt running test>
FIG. 17 shows a pulley layout of the belt running test machine 150 for evaluating wear resistance.

The belt running test machine 150 for wear resistance evaluation includes a driving rib pulley 151 having a pulley diameter of φ60 mm and a driven rib pulley 152 having a pulley diameter of 60 mm provided on the right side thereof. The driven rib pulley 152 is movably provided to the left and right so that an axial load (dead weight DW) can be applied and tension can be applied to the V-ribbed belt B.

For each of the V-ribbed belts of Examples 2-1 to 2-9 and Comparative Example 2, the belt mass was measured, and then wound between the drive rib pulley 151 and the driven rib pulley 152 of the belt running test machine 150 for wear resistance evaluation. Hang and apply a shaft load of 490 N to the right side of the driven rib pulley 152 to apply tension to the V-ribbed belt B, and apply a rotational load of 5.9 kW (8 PS) to drive the driving rib pulley 151 at 3500 rpm in a normal temperature atmosphere. The belt was run at a rotational speed. Then, the belt running was stopped 24 hours after the start of running, the belt mass of the V-ribbed belt was measured, and the weight loss was obtained as a percentage.

<Bend fatigue test belt running test>
FIG. 18 shows a pulley layout of a belt running test machine 160 for evaluating bending fatigue resistance.

The belt running test machine 160 for evaluating bending fatigue resistance includes a driving rib pulley 161 having a pulley diameter of φ60 mm, a first driven rib pulley 162a having a pulley diameter of φ60 mm provided above, a driving rib pulley 161 and a first driven rib pulley 162a. Pulleys provided on the right side of the intermediate portion of the second driven rib pulley 162b having a pulley diameter of φ60 mm and on the right side of the intermediate portions of the drive rib pulley 161 and the first driven rib pulley 162a, respectively, And a pair of idler pulleys 163 having a diameter of 50 mm. The first driven rib pulley 162a is provided movably up and down so as to apply a shaft load (dead weight DW) and apply tension to the V-ribbed belt B. In this belt running test machine 160 for evaluating bending fatigue resistance, bending fatigue is accelerated by bending the V-ribbed belt B to the back side to increase the strain generated at the tip of the V-rib.

For each of the V-ribbed belts of Examples 2-1 to 2-9 and Comparative Example 2, the belt running test machine 160 for evaluating bending fatigue resistance has a compressed rubber layer as a driving rib pulley 161 and first and second driven rib pulleys. 162a and 162b, and the back rubber layer is wound around the idler pulley 163 so as to be in contact with each other, and an axial load of 588 N is applied to the first driven rib pulley 162a to apply tension to the V-ribbed belt B. The driving rib pulley 161 was rotated at a rotational speed of 5100 rpm under the atmospheric temperature of 70 ° C. to run the belt. The belt travel was periodically stopped and whether or not a crack was generated in the compressed rubber layer was visually confirmed, and the belt travel time until the occurrence of the crack was confirmed was defined as the crack generation life.

(Test evaluation results)
The test results are shown in Table 2. Hereinafter, the content of the cellulose fine fiber means a part by mass with respect to 100 parts by mass of the rubber component even if not particularly described.

<Average fiber diameter / fiber diameter distribution>
It can be seen that the cellulose fine fibers contained in the rubber composition forming the compressed rubber layer of each V-ribbed belt of Example 2-1 to Example 2-9 all have a wide fiber diameter distribution.

<Friction coefficient>
While the friction coefficient of Comparative Example 2 was 0.6, the friction coefficients of Examples 2-1 to 2-9 were in the range of 0.6 to 1.1, which was equivalent to Comparative Example 2 or It can be seen that it is somewhat larger than Comparative Example 2. However, for all of Examples 2-1 to 2-9, the amount of change (increase) between the friction coefficient at the time of drying and the friction coefficient at the time of drying is smaller than 0.9 in the case of Comparative Example 2. I understand that. In particular, Example 2-3 to Example 2-6 in which the content of cellulose fine fibers is 5 parts by mass or more, and Examples 2-7 to Example 2 including both cellulose fine fibers and nylon short fibers 9 shows that the increase amount is -0.05 to 0.05, which is close to 0, and therefore, the increase in the coefficient of friction during drying after being flooded is suppressed. Even in the case of Example 2-1 having the smallest content of cellulose fine fibers (1 part by mass), the change in the friction coefficient is 0.5, which is close to half that of Comparative Example 2.

From the above, it can be seen that the change in the coefficient of friction after water exposure can be suppressed by incorporating fine cellulose fibers into the rubber composition forming the compressed rubber layer. This effect is exhibited both in the case of not containing nylon short fibers and containing only cellulose fine fibers, or in the case of containing both nylon short fibers and cellulosic fine fibers. is there.

<Abrasion resistance>
The weight loss of Comparative Example 2 was improved to 2.8% even in Example 2-1 in which the content of cellulose fine fibers was 1 part by mass with respect to the wear rate of 3.2%, and the content of cellulose fine fibers was It can be seen that the wear resistance is improved as the value increases (in Examples 2-2 to 2-6, 2.7, 2.1, 1.9, 1.8, and 1.7 in order). However, it can be seen that when the content of the fine cellulose fiber exceeds 10 parts by mass, the improvement is small even if the content is further increased (Example 2-4 to Example 2-6).

Moreover, the mass loss of the comparative example 2 in which 15 mass parts of nylon short fibers were contained was 3.2%, and in Example 2-1 in which the content of the cellulose fine fibers was 1 mass part, it was 2.8%. In Example 2-7 in which the content of short nylon fibers is 14 parts by mass and the content of fine cellulose fibers is 1 part by mass, the content is 2.3%. That is, it can be seen that the wear resistance is further improved by including both nylon short fibers and cellulose fine fibers. In Examples 2-7 to 2-9, the total content of cellulose fine fibers and short nylon fibers is the same, but the wear resistance improves as the proportion of the content of cellulose fine fibers increases. I understand.

<Bending fatigue resistance>
In Comparative Example 2 in which the content of short nylon fibers was 15 parts by mass, the crack generation life was 520 hours, whereas in Example 2-1 in which the content of cellulose fine fibers was 1 part by mass, cracks were observed. It can be seen that the generation life is 1205 hours, which is improved more than twice. It can be seen that the crack generation life is further improved by increasing the content of the cellulose fine fiber to 3 parts by mass (Example 2-2), but if it is further increased, the crack generation life is rather shortened (Example 2- 3 to Example 2-6). However, even in Example 2-6 in which the content of fine cellulose fibers is 25 parts by mass, the crack generation life is 900 hours, which is significantly improved as compared with Comparative Example 2.

It can be seen that even when the cellulose fine fiber and the short nylon fiber are used in combination, the bending fatigue resistance is improved as compared with Comparative Example 2. It can also be seen that the bending fatigue resistance improves as the proportion of the content of cellulose fine fibers increases (Examples 2-7 to 2-9).

As described above, by incorporating cellulose fine fibers into the rubber composition forming the compressed rubber layer, the friction coefficient stability (suppression of changes due to moisture), wear resistance, flex fatigue resistance, etc. have been improved. A V-ribbed belt can be produced.

[Embodiment 3]
(Flat Belt C)
FIG. 12 schematically shows the flat belt C of the third embodiment. The flat belt C according to the third embodiment is used in applications that require a long life in use under relatively high load conditions such as a drive transmission application such as a blower, a compressor, and a generator, and an auxiliary machine drive application of an automobile. It is the power transmission member used. The flat belt C has, for example, a belt length of 600 to 3000 mm, a belt width of 10 to 20 mm, and a belt thickness of 2 to 3.5 mm.

The flat belt C according to the third embodiment is provided such that an inner rubber layer 121 on the inner peripheral side of the belt, an adhesive rubber layer 122 on the outer peripheral side of the belt, and an outer rubber layer 123 on the outer peripheral side of the belt are laminated. An integrated flat belt body 120 is provided. A core wire 124 is embedded in the adhesive rubber layer 122 so as to form a spiral having a pitch in the belt width direction at an intermediate portion in the belt thickness direction.

The inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 are each formed in a band shape having a horizontally long cross section, and an uncrosslinked rubber composition in which various compounding agents are blended and kneaded with a rubber component is heated. And it is formed with the rubber composition bridge | crosslinked by the crosslinking agent by being pressurized. The thickness of the inner rubber layer 121 is preferably 0.3 mm or more, more preferably 0.5 mm or more, and preferably 3.0 mm or less, more preferably 2.5 mm or less. The thickness of the adhesive rubber layer 122 is, for example, 0.6 to 1.5 mm. The thickness of the outer rubber layer 123 is, for example, 0.6 to 1.5 mm.

At least one of the rubber compositions forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. It is preferable that all the rubber compositions forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 contain such cellulosic fine fibers, but at least the rubber composition forming the inner rubber layer 121 is applied. It is more preferable to contain a cellulosic fine fiber.

The rubber composition that forms the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 is the same as the rubber composition that forms the compression rubber layer 111, the adhesive rubber layer 112, and the back rubber layer 113 of the second embodiment. It has the composition of. Cellulose fine fibers also have the same configuration as that of the second embodiment.

The rubber composition forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 may contain short fibers 126. In particular, the short rubber 126 is preferably contained in the rubber composition forming the inner rubber layer 121. In that case, the short fibers 126 are preferably contained in the inner rubber layer 121 so as to be oriented in the belt width direction. The short fiber 126 has the same configuration as that of the second embodiment.

Further, the core wire 124 has the same configuration as that of the second embodiment.

According to the flat belt C according to the third embodiment, at least one of the rubber compositions forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 that constitutes the flat belt main body 120 in this way is a fiber. By containing a cellulosic fine fiber having a diameter distribution range of 50 to 500 nm, excellent bending fatigue resistance can be obtained. In particular, when the rubber composition forming the inner rubber layer 121 constituting the contact portion contains such cellulosic fine fibers, a high friction resistance and a stable friction coefficient can be obtained.

(Manufacturing method of flat belt C)
A method for manufacturing the flat belt C according to the third embodiment will be described with reference to FIGS. 13, 14, and 15.

The manufacturing method of the flat belt C according to Embodiment 3 includes a material preparation process, a molding process, a crosslinking process, and a finishing process.

<Material preparation process>
Among the uncrosslinked rubber sheets 121 ′, 122 ′, and 123 ′ for the inner rubber layer, the adhesive rubber layer, and the outer rubber layer, those containing cellulosic fine fibers are produced in the same manner as in the second embodiment. . In addition, the preparation of those not containing cellulosic fine fibers is carried out by blending various rubber compounding agents with the rubber component, kneading with a kneader such as a kneader or a Banbury mixer, and the resulting uncrosslinked rubber composition by calendar molding or the like. This is done by forming into a sheet.

Further, the bonding process is performed on the core wire 124 ′ in the same manner as in the second embodiment.

<Molding process>
As shown in FIG. 13A, after the uncrosslinked rubber sheet 121 ′ for the inner rubber layer is wound around the outer periphery of the cylindrical mold 145, the uncrosslinked rubber sheet 122 ′ for the adhesive rubber layer is wound thereon.

Next, as shown in FIG. 13 (b), a core wire 124 'is spirally wound on the uncrosslinked rubber sheet 122' for the adhesive rubber layer, and then again uncrosslinked for the adhesive rubber layer. A rubber sheet 122 'is wound.

Next, as shown in FIG. 13C, the uncrosslinked rubber sheet 123 'for the outer rubber layer is wound around the uncrosslinked rubber sheet 122' for the adhesive rubber layer. As a result, a laminated molded body C ′ is formed on the cylindrical mold 145.

<Crosslinking process>
Subsequently, as shown in FIG. 14, after the laminated molded body C ′ on the cylindrical mold 145 is covered with a rubber sleeve 146, it is set in a vulcanizing can and hermetically sealed, and the cylindrical mold is heated with high-temperature steam or the like. While heating 145, high pressure is applied and the rubber sleeve 146 is pressed in the radial direction on the cylindrical mold 145 side. At this time, the uncrosslinked rubber composition of the laminated molded body C ′ flows, and the crosslinking reaction of the rubber component proceeds. In addition, the adhesion reaction of the core wire 124 ′ also proceeds, and as shown in FIG. A cylindrical belt slab S is formed on the mold 145.

<Polishing and finishing process>
In the polishing and finishing process, the cylindrical mold 145 is taken out from the vulcanizing can, the cylindrical belt slab S formed on the cylindrical mold 145 is removed, and then the outer peripheral surface and / or the inner peripheral surface is polished. To make the thickness uniform.

Finally, a flat belt C is produced by cutting the belt slab S into a predetermined width.

[Other Embodiments]
In the second embodiment, the V-ribbed belt B and the flat belt C are shown in the third embodiment. However, the present invention is not particularly limited thereto, and the rubber containing cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. As long as at least a part of the belt body is formed of the composition, it may be another friction transmission belt such as a low edge V belt or a wrapped V belt, or a toothed belt of a meshing transmission belt.

[Flat belt]
The flat belts of Examples 3-1 to 3-6 and Comparative Examples 3-1 to 3-2 below were produced. Details of each are also shown in Table 3.

<Example 3-1>
A master batch of fine cellulose fibers / EPDM was produced in the same manner as in Example 2-1.

Subsequently, EPDM was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the cellulose fine fiber content was 1 part by mass when the total EPDM was 100 parts by mass.

And while kneading EPDM and cellulose fine fiber, with respect to 100 parts by mass of EPDM, 40 parts by mass of HAF carbon black (trade name: Diamond Black H) manufactured by Mitsubishi Chemical Co., Ltd., process oil (product manufactured by Sun Oil Co., Ltd.) Name: Thumper 2280) 5 parts by mass, stearic acid as a processing aid (manufactured by Shin Nippon Chemical Co., Ltd., trade name: stearic acid 50S) 0.5 parts by mass, zinc oxide as a vulcanization accelerator (Sakai Chemical Co., Ltd.) Product name: Zinc oxide (3 types) 5 parts by mass, benzimidazole anti-aging agent (Ouchi Shinsei Chemical Co., Ltd., product name: NOCRACK MB) 2 parts by mass, and organic peroxide (JP An uncrosslinked rubber composition was prepared by adding 6 parts by mass of each product (trade name: Peroximon F-40, purity 40% by mass) manufactured by Oil Co. and continuing kneading.

Using this uncrosslinked rubber composition, a flat belt of Example 3-1 having the same configuration as that of Embodiment 3 in which the inner rubber layer was formed so that the line direction was the belt width direction was produced.

The V-ribbed belt of Example 3-1 had a belt length of 1118 mm, a belt width of 10 mm, and a belt thickness of 2.8 mm. The adhesive rubber layer and the outer rubber layer were formed of a rubber composition not containing fine cellulose fibers and short fibers, and the core wire was formed of a twisted yarn made of polyester fiber subjected to an adhesion treatment.

<Example 3-2>
A flat belt of Example 3-2 was produced in the same manner as Example 3-1, except that the content of cellulose fine fibers was 3 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 3-3>
A flat belt of Example 3-3 was produced in the same manner as in Example 3-1, except that the content of cellulose fine fiber was 5 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 3-4>
A flat belt of Example 3-4 was produced in the same manner as in Example 3-1, except that the content of the fine cellulose fiber was 10 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 3-5>
A flat belt of Example 3-5 was produced in the same manner as in Example 3-1, except that the content of cellulose fine fibers was 15 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 3-6>
A flat belt of Example 3-6 was produced in the same manner as in Example 3-1, except that the content of the fine cellulose fiber was 25 parts by mass with respect to 100 parts by mass of the rubber component.

<Comparative Example 3-1>
A flat belt of Comparative Example 2-1 was produced in the same manner as in Example 3-1, except that cellulose fine fibers were not contained in the rubber composition forming the inner rubber layer.

<Comparative Example 3-2>
Except that the rubber composition forming the inner rubber layer does not contain fine cellulose fibers and 5 parts by mass of nylon short fibers with respect to 100 parts by mass of the rubber component, the same as in Example 3-1. A flat belt of Comparative Example 2-2 was produced.

(Test evaluation method)
<Average fiber diameter / fiber diameter distribution>
Samples were collected from the rubber compositions forming the inner rubber layers of the flat belts of Examples 3-1 to 3-6, and the average fiber diameter of the cellulose fine fibers was measured in the same manner as in Example 2. The maximum value and the minimum value of the fiber diameter were determined.

<Friction and wear characteristics evaluation belt running test>
FIG. 19 shows a pulley layout of a belt running test machine 170 for evaluating friction / wear characteristics.

The belt running test machine 170 for evaluating friction / wear characteristics includes a driving flat pulley 171 having a pulley diameter of 120 mm, a first driven flat pulley 172 having a pulley diameter of 120 mm provided above the right driving pulley 171 and a right at an intermediate position between them. And a second driven flat pulley 173 having a pulley diameter of φ50 mm provided on the side. The second driven flat pulley 173 is movably provided to the left and right so as to apply an axial load (dead weight DW) and apply tension to the flat belt C.

For each flat belt C of Example 3-1 to Example 3-6 and Comparative Example 3-1 to Comparative Example 3-2, the driving flat pulley 171 of the belt running test machine 170 for evaluating friction and wear characteristics, the first The second driven flat pulleys 72 and 73 are wound around, and a 98 N axial load is applied to the right side of the second driven flat pulley 173 to apply tension to the flat belt C. The belt was run by applying a rotational load of 8.8 kW and rotating the drive pulley 171 at a rotational speed of 4800 rpm under an ambient temperature of 120 ° C. Then, the belt running was stopped 24 hours after the running started, and the friction coefficient of the surface of the inner rubber layer after the belt running was obtained by the same method as in Example 2 using the friction coefficient measuring device 140 shown in FIG. . As the test pulley 141, a flat pulley having a pulley diameter of φ65 mm was used.

In addition, the same test was performed with the belt running time set to 500 hours, and the amount of change in the friction coefficient was calculated when the belt running time was set to 24 hours.

Further, the running surface of the driving flat pulley 171 and the first and second driven flat pulleys 72 and 73 after the belt running for 24 hours is visually observed to perform a sensory evaluation of the surface state, and the state from the amount of rubber adhesion and texture The sticking wear occurrence index was numerically determined as follows.

When sticky eraser residue is attached: 100
When there is a powdery deposit: 50,
When there is no deposit: 0
Here, the rubber that is difficult to collect becomes powdery and tends to fall off the belt surface. Even if the wear resistance is good, if the state of the wear powder is poor, the wear powder becomes a foreign substance, and the product value is evaluated low.

<Abrasion resistance evaluation belt running test>
FIG. 20 shows a pulley layout of the belt running test machine 180 for evaluating wear resistance.

The belt running test machine 180 for wear resistance evaluation includes a driving flat pulley 181 having a pulley diameter of φ100 mm and a driven flat pulley 182 having a pulley diameter of 100 mm provided on the left side thereof. The driving flat pulley 181 is provided so as to be movable left and right so as to apply an axial load (dead weight DW) and apply tension to the flat belt C.

For each flat belt C of Example 3-1 to Example 3-6 and Comparative Example 3-1 to Comparative Example 3-2, the belt mass was measured, and then the belt running tester 180 for wear resistance evaluation was driven. Wrapped between the flat pulley 181 and the driven flat pulley 182 to apply a shaft load of 300 N to the right side of the driving flat pulley 181 to apply tension to the flat belt C, and rotate the driven flat pulley 182 by 12 N · m. Torque was applied, and the drive flat pulley 181 was rotated at a rotational speed of 2000 rpm under the atmospheric temperature of 100 ° C. to run the belt. Then, the belt running was stopped 24 hours after the start of running, the belt mass of the flat belt C was measured, the weight loss was determined, and the relative value was calculated with the weight loss of Comparative Example 3-1 being 100.

(Test evaluation results)
The test results are shown in Table 3. Hereinafter, the content of the cellulose fine fiber means a part by mass with respect to 100 parts by mass of the rubber component even if not particularly described.

<Average fiber diameter / fiber diameter distribution>
It can be seen that the cellulose fine fibers contained in the rubber composition forming the inner rubber layer of each flat belt in Examples 3-1 to 3-6 have a wide fiber diameter distribution.

<Friction and wear characteristics>
-Coefficient of friction-
The friction coefficient after running the belt for 24 hours in Comparative Example 3-1 was 0.85, but also in Example 3-1 and Example 3-2, it was the same 0.85, relative to 100 parts by mass of the rubber component. When the cellulose fine fiber content is about 1 to 3 parts by mass, no change is observed in the friction coefficient. It can be seen that when the content of the cellulose fine fiber is further increased (Examples 3-3 to 3-6), the content decreases somewhat, and at 25 parts by mass (Examples 3-6), it is 0.6.

In the case of Comparative Example 3-2 in which 5 parts by mass of nylon short fibers are blended, the coefficient of friction is 0.75, and the content of cellulose fine fibers is 10 parts by mass. Same as the case.

The friction coefficient after running the belt for 500 hours, compared with the friction coefficient after running the belt for 24 hours, decreases to 0.35 and 0.25 in order in Comparative Example 3-1 and Comparative Example 3-2. In Examples 3-1 to 3-6, the decrease is 0.15 at the maximum (Examples 3-1 and 2-2). When the content of the cellulose fine fiber is increased, the decrease is further reduced. When the content is 10 parts by mass or more (Examples 3-4 to 3-6), after running the belt for 24 hours and after running the belt for 500 hours. It can be seen that the coefficient of friction is the same value.

From the above, it can be seen that a flat belt having a small change in friction coefficient with time can be obtained by forming the inner rubber layer from a rubber composition containing fine cellulose fibers.

-Adhesive wear index-
The adhesive wear occurrence index of Comparative Example 3-1 and Comparative Example 3-2 was evaluated as 100 and 90, whereas when the rubber composition containing cellulose fine fibers was used, the content was the smallest (1 (Mass part) In Example 3-1, the adhesive wear occurrence index is 45, which shows a marked improvement. By increasing the content, the adhesive wear occurrence index was further improved. In Example 3-6 containing 25 parts by mass of cellulose fine fibers, the evaluation was 10 (powder with less adhesion on the belt surface and low adhesive powder) It can be seen that there are many body-shaped ones).

In the case of Comparative Example 3-2 containing nylon short fibers, an improvement is seen as compared with Comparative Example 3-1, but this is not remarkable.

From the above, it can be seen that the adhesive wear occurrence index of the flat belt is improved by forming the inner rubber layer with the rubber composition containing cellulose fine fibers.

<Abrasion resistance>
The evaluation of abrasion resistance of Comparative Example 3-1 and Comparative Example 3-2 is 100, whereas Example 3-1 in which the content of cellulose fine fibers is 1 part by mass is improved to 65, It can be seen that the evaluation is further improved by further increasing the content. However, the evaluation is 50 or 45 when the content of cellulose fine fibers is in the range of 3 to 25 parts by mass (Example 3-2 to Example 3-6), and even if the content of cellulose fine fibers is increased, The improvement in wear tends to saturate.

[Embodiment 4]
[V-ribbed belt B]
21 and 22 show a V-ribbed belt B (power transmission belt) according to the fourth embodiment. The V-ribbed belt B according to the fourth embodiment is an endless power transmission member used in, for example, an accessory drive belt transmission device provided in an engine room of an automobile. The V-ribbed belt B according to Embodiment 4 has, for example, a belt length of 700 to 3000 mm, a belt width of 10 to 36 mm, and a belt thickness of 4.0 to 5.0 mm.

The V-ribbed belt B according to the fourth embodiment is a rubber V-ribbed belt main body configured in a three-layer structure including a compression rubber layer 211 on the belt inner circumferential side, an intermediate adhesive rubber layer 212, and a back rubber layer 213 on the belt outer circumferential side. 210 is provided. A core wire 214 is embedded in an intermediate portion in the thickness direction of the adhesive rubber layer 212 in the V-ribbed belt main body 210 so as to form a spiral having a pitch in the belt width direction. Note that a back reinforcing cloth may be provided instead of the back rubber layer 213, and the V-ribbed belt main body 210 may be configured as a double layer of the compression rubber layer 211 and the adhesive rubber layer 212.

The compression rubber layer 211 is provided such that a plurality of V ribs 215 hang down to the inner peripheral side of the belt. The plurality of V ribs 215 are each formed in a ridge having a substantially inverted triangular cross section extending in the belt length direction, and provided in parallel in the belt width direction. For example, each V rib 215 has a rib height of 2.0 to 3.0 mm and a width between base ends of 1.0 to 3.6 mm. The number of V ribs 215 is, for example, 3 to 6 (6 in FIG. 21).

The compression rubber layer 211 includes a surface rubber layer 211a constituting a pulley contact portion provided in a layer shape along the entire pulley contact surface, and an internal rubber layer 211b provided on the inner side of the belt with respect to the surface rubber layer 211a. Have The thickness of the surface rubber layer 211a is, for example, 50 to 500 μm.

The surface rubber layer 211a is a rubber composition in which an uncrosslinked rubber composition obtained by mixing and kneading various rubber compounding agents in addition to a foaming agent and cellulose fine fibers in a rubber component is heated and pressurized to be crosslinked by a crosslinking agent. It is formed of things. The rubber composition for forming the surface rubber layer 211a is a porous rubber composition in which a large number of hollow portions 216a are formed inside by foaming of a foaming agent, and a large number of recessed holes 217a exposed on the surface are formed. It is a thing. Here, “fine fiber” in the present application means a fiber having a fiber diameter of 1.0 μm or less.

Examples of the rubber component of the rubber composition forming the surface rubber layer 211a include ethylene-propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer, and other ethylene- α-olefin elastomer; chloroprene rubber (CR); chlorosulfonated polyethylene rubber (CSM); hydrogenated acrylonitrile rubber (H-NBR), natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), nitrile Examples thereof include rubber (NBR), silicone rubber (Q), and fluoro rubber (FKM). The rubber component of the rubber composition forming the surface rubber layer 211a is preferably one or more of these blend rubbers.

As the foaming agent, for example, an ADCA foaming agent containing azodicarbonamide as a main component, a DPT foaming agent containing dinitrosopentamethylenetetramine as a main component, and p, p′-oxybisbenzenesulfonylhydrazide as a main component. Examples of the thermal decomposition type include organic foaming agents such as OBSH foaming agents and HDCA foaming agents mainly composed of hydrazodicarbonamide. It is preferable that a foaming agent is 1 type, or 2 or more types among these. In addition, as a commercially available thermal decomposition type foaming agent, the Sanyo Kasei Co., Ltd. brand name: Cell microphone series etc. are mentioned, for example.

The decomposition temperature of the foaming agent is preferably 100 ° C or higher, more preferably 140 ° C or higher, and preferably 230 ° C or lower, more preferably 210 ° C or lower. The blending amount of the foaming agent is preferably 0.5 parts by mass or more, more preferably 4 parts by mass or more, and preferably 10 parts by mass or less, more preferably 7 parts by mass with respect to 100 parts by mass of the rubber component. It is as follows.

The rubber composition forming the surface rubber layer 211a contains a decomposition residue after the foaming agent decomposes and foams. Specifically, for example, in the case of an ADCA foaming agent, urazole biurea cyanurate is included as a decomposition residue in the rubber composition forming the surface rubber layer 211a. In the case of a DPT foaming agent, hexamethylenetetramine is included. In the case of the OBSH-based blowing agent, polydithiophenyl ether and polythiophenylbenzenesulfonyl ether are included. In the case of an HDCA-based blowing agent, urazole will be included.

Cellulosic fine fiber is a fiber material derived from cellulose fine fiber composed of a skeletal component of a plant cell wall obtained by finely loosening plant fiber. Examples of the cellulosic fine fiber plant include wood, bamboo, rice (rice straw), potato, sugar cane (bagasse), aquatic plants, seaweed and the like. Of these, wood is preferred. When the porous rubber composition forming the surface rubber layer 211a contains such cellulosic fine fibers, a high reinforcing effect is exhibited.

The cellulose-based fine fiber may be either the cellulose fine fiber itself or a hydrophobic cellulose fine fiber that has been subjected to a hydrophobic treatment. Moreover, you may use together cellulose fine fiber itself and hydrophobized cellulose fine fiber as a cellulosic fine fiber. From the viewpoint of dispersibility, the cellulosic fine fibers preferably include hydrophobized cellulose fine fibers. Examples of the hydrophobized cellulose fine fibers include cellulose fine fibers in which some or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups, and cellulose fine fibers that have been subjected to a hydrophobized surface treatment with a surface treatment agent.

Examples of hydrophobization for obtaining cellulose fine fibers in which part or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups include esterification (acylation) (alkyl esterification, complex esterification, β-ketoesterification, etc.) ), Alkylation, tosylation, epoxidation, arylation and the like. Of these, esterification is preferred. Specifically, in the esterified hydrophobized cellulose fine fiber, part or all of the hydroxyl groups of cellulose are carboxylic acids such as acetic acid, acetic anhydride, propionic acid, butyric acid, or halides thereof (particularly chlorides). It is the cellulose fine fiber acylated by. Examples of the surface treatment agent for obtaining cellulose fine fibers hydrophobized and surface-treated with the surface treatment agent include silane coupling agents.

From the viewpoint of enhancing the reinforcing effect of the surface rubber layer 211a, the lower limit of the fiber diameter distribution of the cellulosic fine fibers is preferably 10 nm or more, more preferably 20 nm or more. An upper limit becomes like this. Preferably it is 1 micrometer or less, More preferably, it is 700 nm or less, More preferably, it is 500 nm or less. From the viewpoint of enhancing the reinforcing effect of the surface rubber layer 211a, the fiber diameter distribution range of the cellulosic fine fibers preferably includes 20 nm to 1 μm, more preferably includes 20 to 700 mm, and includes 20 to 500 nm. Further preferred.

The average fiber diameter of the cellulosic fine fibers contained in the rubber composition forming the surface rubber layer 211a is preferably 200 nm or less, more preferably 100 nm or less, from the viewpoint of enhancing the reinforcing effect of the surface rubber layer 211a. The average fiber diameter of the cellulosic fine fibers contained in the rubber composition forming the surface rubber layer 211a is preferably 3 nm or more.

The distribution of the fiber diameter of the cellulosic fine fibers was determined by freeze-grinding a sample of the rubber composition forming the surface rubber layer 211a and then observing the cross section with a transmission electron microscope (TEM), and 50 cellulosic fine fibers. The fiber diameter is measured by arbitrarily selecting the fiber, and it is obtained based on the measurement result. The average fiber diameter of the cellulosic fine fibers is obtained as the number average of the fiber diameters of 50 arbitrarily selected cellulosic fine fibers.

The cellulosic fine fibers may be either high aspect ratio manufactured by mechanical defibrating means, or manufactured by chemical defibrating means. Of these, those produced by chemical defibrating means are preferred. Moreover, you may use together what was manufactured by the mechanical defibration means, and what was manufactured by the chemical defibration means as a cellulose fine fiber. Examples of the defibrating apparatus used for the mechanical defibrating means include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a grinder, and a bead mill. Examples of the treatment used for the chemical defibrating means include acid hydrolysis treatment.

The content of the cellulosic fine fibers in the rubber composition forming the surface rubber layer 211a is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the rubber component from the viewpoint of enhancing the reinforcing effect of the surface rubber layer 211a. More preferably, it is 1 mass part or more, More preferably, it is 5 mass parts or more, Preferably it is 30 mass parts or less, More preferably, it is 20 mass parts or less, More preferably, it is 10 mass parts or less.

The content of the cellulosic fine fibers with respect to 100 parts by mass of the rubber component in the rubber composition forming the surface rubber layer 211a may be less or more than the blending amount of the foaming agent. It may be the same as the content with respect to 100 parts by mass of the component or either. The total content of the foaming agent and the cellulose-based fine fiber with respect to 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably. Is 20 parts by mass or less.

Examples of rubber compounding agents include reinforcing materials, oils, processing aids, vulcanization acceleration aids, crosslinking agents, co-crosslinking agents, and vulcanization accelerators.

As the reinforcing material, carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like. Silica is also mentioned as the reinforcing material. It is preferable that a reinforcing material is 1 type, or 2 or more types among these. The content of the reinforcing material is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. It is below mass parts. When the reinforcing material is carbon black, the content with respect to 100 parts by mass of the rubber component may be less than or more than the content of the cellulosic fine fibers, or even 100 masses of the rubber component of the cellulosic fine fibers. Even if it is the same as content with respect to a part, either may be sufficient. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and preferably 45 parts by mass or less, more preferably. Is 40 parts by mass or less.

Oils include, for example, petroleum-based softeners, mineral oils such as paraffin wax, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, fall raw oil, wax, rosin, pine And vegetable oils such as oil. The oil is preferably one or more of these. The oil content is, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the vulcanization acceleration aid include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof. Among these, the vulcanization acceleration aid is preferably one or more. The content of the vulcanization acceleration aid is, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the crosslinking agent include organic peroxides and sulfur. As a crosslinking agent, an organic peroxide may be blended, sulfur may be blended, or both of them may be used in combination. In the case of an organic peroxide, the amount of the crosslinking agent is, for example, 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. In the case of sulfur, the compounding amount is 100 parts by mass of the rubber component of the rubber composition. For example, 1 to 5 parts by mass.

Examples of the co-crosslinking agent include maleimide, TAIC, 1,2-polybutadiene, oximes, guanidine, and trimethylolpropane trimethacrylate. The co-crosslinking agent is preferably one or more of these. The content of the co-crosslinking agent is, for example, 0.5 to 15 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the vulcanization accelerator include thiazole type (eg MBT, MBTS etc.), thiuram type (eg TT, TRA etc.), sulfenamide type (eg CZ etc.), dithiocarbamate type (eg BZ-P etc.) And the like. It is preferable that a vulcanization accelerator is 1 type, or 2 or more types among these. The content of the vulcanization accelerator is, for example, 2 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

The rubber composition that forms the surface rubber layer 211a preferably does not contain short fibers such as nylon fiber, aramid fiber, polyester fiber, cotton, etc., but does not impair the reinforcing effect of the surface rubber layer 211a. The short fiber may be included.

The average hole diameter of the concave holes 217a on the surface of the surface rubber layer 211a reduces the difference in friction coefficient between the surface of the surface rubber layer 211a when it is dried and when it is wet, suppresses fluctuations in the coefficient of friction over time, From the viewpoint of suppressing the generation of abnormal noise, particularly abnormal noise when wet and the occurrence of slip when wet, it is preferably 70 μm or more, more preferably 80 μm or more, and preferably 120 μm or less, more preferably 110 μm or less. Here, the hole diameter of the recessed hole 217a is the opening diameter of the recessed hole 217a exposed on the surface of the surface rubber layer 211a, and the average hole diameter is obtained as the number average of 50 to 100 hole diameters measured from the surface image. be able to. In addition, the average hole diameter of the concave hole 217a can be controlled by the type and blending amount of the foaming agent.

The inner rubber layer 211b is formed of a solid rubber composition in which an uncrosslinked rubber composition obtained by mixing and kneading various rubber compounding agents with a rubber component is heated and pressurized and crosslinked with a crosslinking agent.

As the rubber component of the rubber composition forming the internal rubber layer 211b, the same rubber component as the surface rubber layer 211a can be cited. The rubber component of the rubber composition forming the internal rubber layer 211b is preferably the same as the rubber component of the rubber composition forming the surface rubber layer 211a. Examples of the rubber compounding agent include a reinforcing material, oil, a processing aid, a vulcanization acceleration aid, a crosslinking agent, a co-crosslinking agent, and a vulcanization accelerator, as with the surface rubber layer 211a.

The rubber composition for forming the inner rubber layer 211b may contain cellulosic fine fibers as with the surface rubber layer 211a. The uncrosslinked rubber composition before crosslinking of the rubber composition that forms the inner rubber layer 211b is preferably not blended with a foaming agent. However, the foaming agent is blended within a range that does not impair the strength of the inner rubber layer 211b. It may be.

The adhesive rubber layer 212 is configured in a band shape having a horizontally long cross section, and has a thickness of, for example, 1.0 to 2.5 mm. The back rubber layer 213 is also formed in a band shape having a horizontally long cross section, and has a thickness of, for example, 0.4 to 0.8 mm. It is preferable that a woven fabric pattern is provided on the surface of the back rubber layer 213 from the viewpoint of suppressing the generation of sound during back driving. The adhesive rubber layer 212 and the back rubber layer 213 are formed of a rubber composition in which various rubber compounding agents are blended into a rubber component and kneaded and kneaded, and the uncrosslinked rubber composition is heated and pressurized to be cross-linked by a cross-linking agent. Yes.

As the rubber component of the rubber composition forming the adhesive rubber layer 212 and the back rubber layer 213, the same rubber component as the surface rubber layer 211a can be used. The rubber component of the rubber composition forming the adhesive rubber layer 212 and the back rubber layer 213 may be the same as the surface rubber layer 211a or the internal rubber layer 211b. Examples of the rubber compounding agent include a reinforcing material, oil, a processing aid, a vulcanization acceleration aid, a crosslinking agent, a co-crosslinking agent, and a vulcanization accelerator, as with the surface rubber layer 211a.

The core wire 214 is composed of a twisted yarn formed of polyamide fiber, polyester fiber, aramid fiber, polyamide fiber or the like. The diameter of the core wire 214 is, for example, 0.5 to 2.5 mm, and the dimension between the centers of adjacent core wires 214 in the cross section is, for example, 0.05 to 0.20 mm. The core wire 214 is subjected to an adhesive treatment for imparting adhesiveness to the V-ribbed belt main body 210.

According to the V-ribbed belt B according to the fourth embodiment having the above-described configuration, the porous rubber composition forming the surface rubber layer 211a contains cellulosic fine fibers, so that a high reinforcing effect is exhibited, crack resistance and The wear resistance is improved, and as a result, high durability can be obtained. Further, it is possible to suppress the fluctuation of the friction coefficient with time. Furthermore, the difference in the coefficient of friction between the surface rubber layer 211a when it is dried and when it is wet can be kept small, and it is possible to suppress the generation of abnormal noise when wet and the occurrence of slip when wet. This is considered to be because a decrease in the friction coefficient is suppressed by the hydrophilic cellulose fine fibers absorbing moisture.

FIG. 23 shows a pulley layout of an auxiliary drive belt transmission device 220 for an automobile using the V-ribbed belt B according to the fourth embodiment. The accessory drive belt transmission device 220 is of a serpentine drive type in which a V-ribbed belt B is wound around six pulleys of four rib pulleys and two flat pulleys to transmit power.

In this auxiliary machine driving belt transmission 220, a rib pulley power steering pulley 221 is provided at the uppermost position, and a rib pulley AC generator pulley 222 is provided below the power steering pulley 221. A flat pulley tensioner pulley 223 is provided at the lower left of the power steering pulley 221, and a flat pulley water pump pulley 224 is provided below the tensioner pulley 223. Further, a crankshaft pulley 225 of a rib pulley is provided on the lower left side of the tensioner pulley 223, and an air conditioner pulley 226 of a rib pulley is provided on the lower right side of the crankshaft pulley 225. These pulleys are made of, for example, a metal stamped product, a casting, or a resin molded product such as nylon resin or phenol resin, and have a pulley diameter of φ50 to 150 mm.

In this accessory drive belt transmission 220, the V-ribbed belt B is wound around the power steering pulley 221 so that the V-rib 215 side contacts, and then wound around the tensioner pulley 223 so that the back of the belt contacts. After that, it is wound around the crankshaft pulley 225 and the air conditioner pulley 226 in order so that the V-rib 215 side contacts, and further wound around the water pump pulley 224 so that the back surface of the belt contacts, and the V-rib 215 side contacts Thus, it is wound around the AC generator pulley 222 and finally returned to the power steering pulley 221. The belt span length, which is the length of the V-ribbed belt B spanned between the pulleys, is, for example, 50 to 300 mm. Misalignment that can occur between pulleys is 0-2 °.

(Manufacturing method of V-ribbed belt B)
A method for manufacturing the V-ribbed belt B according to the fourth embodiment will be described with reference to FIGS.

24 and 25 show a belt mold 230 used for manufacturing the V-ribbed belt B according to the fourth embodiment.

The belt mold 230 includes a cylindrical inner mold 231 and an outer mold 232, which are provided concentrically.

The inner mold 231 is made of a flexible material such as rubber. The outer mold 232 is made of a rigid material such as metal. The inner peripheral surface of the outer mold 232 is formed as a molding surface, and V rib forming grooves 233 having the same shape as the V rib 215 are provided at a constant pitch in the axial direction on the inner peripheral surface of the outer mold 232. . The outer mold 232 is provided with a temperature control mechanism that controls the temperature by circulating a heat medium such as water vapor or a coolant such as water. Further, a pressurizing means for pressurizing and expanding the inner mold 231 from the inside is provided.

The manufacturing method of the V-ribbed belt B according to Embodiment 4 includes a material preparation process, a molding process, a crosslinking process, and a finishing process.

<Material preparation process>
-Uncrosslinked rubber sheet 211a 'for the surface rubber layer-
First, cellulosic fine fibers are put into a kneaded rubber component and dispersed by kneading.

Here, as a method for dispersing the cellulose-based fine fibers in the rubber component, for example, a dispersion (gel) in which the cellulose-based fine fibers are dispersed in water is added to the rubber component kneaded with an open roll, A method of vaporizing moisture while kneading them, a master of cellulose fine fibers / rubber obtained by mixing a dispersion (gel) in which cellulosic fine fibers are dispersed in water and rubber latex to vaporize the moisture Obtained by mixing the batch into a rubber component that has been masticated, mixing a dispersion in which cellulosic fine fibers are dispersed in a solvent, and a solution in which the rubber component is dissolved in the solvent, and evaporating the solvent. Cellulose fine fiber / rubber masterbatch is put into the kneaded rubber component, dispersion (gel) in which cellulose fine fiber is dispersed in water is freeze-dried and pulverized And what, how to put into a rubber component is masticated, methods and the like to introduce cellulosic microfibers made hydrophobic in rubber component is masticated.

Next, while kneading the rubber component and the cellulosic fine fibers, the foaming agent and various rubber compounding agents are added and the kneading is continued.

Then, the obtained uncrosslinked rubber composition is molded into a sheet shape by calendar molding or the like to produce an uncrosslinked rubber sheet 211a 'for the surface rubber layer.

-Uncrosslinked rubber sheets 211b'12 ', 13' for internal rubber layer, adhesive rubber layer, and back rubber layer
Various rubber compounding agents are blended into the rubber component and kneaded with a kneader such as a kneader or Banbury mixer, and the resulting uncrosslinked rubber composition is molded into a sheet shape by calendering or the like, for an internal rubber layer, adhesive rubber The uncrosslinked rubber sheets 211b ′, 12 ′, and 13 ′ for the layer and the back rubber layer are prepared.

-Core 214'-
An adhesive treatment is applied to the core wire 214 ′. Specifically, the core wire 214 ′ is subjected to an RFL adhesion treatment in which it is immersed in a resorcin / formalin / latex aqueous solution (hereinafter referred to as “RFL aqueous solution”) and heated. In addition, if necessary, a base adhesive treatment in which the substrate is immersed in a base adhesive treatment solution and heated before the RFL adhesive treatment and / or a rubber paste adhesive treatment in which the RFL adhesive treatment is immersed in rubber paste and dried are performed.

<Molding process>
As shown in FIG. 26, a rubber sleeve 235 is placed on a cylindrical drum 234 having a smooth surface, and an uncrosslinked rubber sheet 213 ′ for the back rubber layer and an uncrosslinked rubber sheet 212 for the adhesive rubber layer are placed on the outer periphery thereof. 'Are wound in order and laminated, and a core wire 214' is wound spirally around the cylindrical inner mold 231, and further, an uncrosslinked rubber sheet 212 'for an adhesive rubber layer and an inner rubber layer are further wound thereon. The uncrosslinked rubber sheet 211b 'for use is wound in order, and the uncrosslinked rubber sheet 211a' for the surface rubber layer is further wound thereon. At this time, a laminated molded body B ′ is formed on the rubber sleeve 235. Note that the uncrosslinked rubber sheet 211a ′ for the surface rubber layer is used so that the processing direction corresponds to the belt length direction, or the processing direction corresponds to the belt width direction. Or either.

<Crosslinking process>
The rubber sleeve 235 provided with the laminated molded body B ′ is removed from the cylindrical drum 234, and as shown in FIG. 27, it is set in the inner peripheral surface side of the outer mold 232, and as shown in FIG. The inner mold 231 is positioned and sealed in the rubber sleeve 235 set on the outer mold 232.

Next, the outer mold 232 is heated and pressurized by injecting high-pressure air or the like into the sealed interior of the inner mold 231. At this time, the inner mold 231 expands, and the uncrosslinked rubber sheet 211a ′ for the surface rubber layer in the laminated molded body B ′ is provided along the molding surface of the outer mold 232, and other uncrosslinked rubber sheets are provided. 211b ′, 12 ′ and 13 ′ enter after being compressed, their cross-linking progresses and integrates, and the core wire 214 ′ is also combined and integrated, and further, an uncrosslinked rubber sheet 211a for the surface rubber layer In FIG. 29, the foaming agent is foamed, and finally, a cylindrical belt slab S is formed as shown in FIG. The molding temperature of the belt slab S is, for example, 100 to 180 ° C., the molding pressure is, for example, 0.5 to 2.0 MPa, and the molding time is, for example, 10 to 60 minutes.

<Finishing process>
The inside of the inner mold 231 is decompressed to release the seal, the belt slab S molded between the inner mold 231 and the outer mold 232 is taken out via the rubber sleeve 235, and the V rib 215 of the belt slab S is taken as necessary. The V-ribbed belt B is manufactured by grinding the surface on the side, cutting it into a predetermined width, and turning it upside down.

[Embodiment 5]
(V-ribbed belt B)
The V-ribbed belt B (transmission belt) according to the fifth embodiment has the same external configuration as that of the fourth embodiment, and will be described below with reference to FIGS. 21 and 22.

In the V-ribbed belt B according to the fifth embodiment, the surface rubber layer 211a is not yet kneaded in the presence of a supercritical fluid or a subcritical fluid, in which various rubber compounding agents are added to the rubber component in addition to the cellulosic fine fibers. The crosslinked rubber composition is formed of a rubber composition that is heated and pressurized and crosslinked with a crosslinking agent. In addition, the rubber composition forming the surface rubber layer 211a is exposed to the surface while the impregnated supercritical fluid or subcritical fluid is changed into a gas by decompression to form a large number of hollow portions 216a inside. This is a porous rubber composition in which a large number of concave holes 217a are formed.

The average hole diameter of the concave holes 217a on the surface of the surface rubber layer 211a reduces the difference in friction coefficient between the surface of the surface rubber layer 211a when it is dried and when it is wet, suppresses fluctuations in the coefficient of friction over time, From the viewpoint of suppressing the generation of abnormal noise, particularly abnormal noise when wet and the occurrence of slip when wet, it is preferably 70 μm or more, more preferably 80 μm or more, and preferably 120 μm or less, more preferably 110 μm or less. Here, the hole diameter of the recessed hole 217a is the opening diameter of the recessed hole 217a exposed on the surface of the surface rubber layer 211a, and the average hole diameter is obtained as the number average of 50 to 100 hole diameters measured from the surface image. be able to. The average pore diameter of the concave holes 217a can be controlled by the preparation conditions of the rubber composition for forming the surface rubber layer 211a using a supercritical fluid or a subcritical fluid foaming agent.

Other configurations and operational effects are the same as those in the fourth embodiment.

(Manufacturing method of V-ribbed belt B)
In the method for manufacturing the V-ribbed belt B according to the fifth embodiment, the production of the uncrosslinked rubber sheet 211a ′ for the surface rubber layer in the material preparation step is performed as follows.

First, in the presence of a supercritical fluid or a subcritical fluid, a rubber component, a cellulosic fine fiber, and various rubber compounding agents are kneaded and then decompressed to obtain an uncrosslinked rubber composition. At this time, the supercritical fluid or subcritical fluid impregnated in the uncrosslinked rubber composition is phase-changed into a gas under reduced pressure to obtain a porous uncrosslinked rubber composition.

Here, “supercritical fluid” refers to a fluid in a supercritical state. The “supercritical state” refers to a state where the temperature is equal to or higher than the critical temperature (Tc) of the fluid and the pressure is equal to or higher than the critical pressure (Pc) of the fluid.

“Subcritical fluid” refers to a fluid in a subcritical state. “Subcritical state” means that only one of temperature and pressure has reached a critical state and the other has not reached a critical state, or both temperature and pressure have not reached a critical state, At least one is a state that is sufficiently higher than normal temperature and pressure and close to the critical state. In the present application, the “subcritical state” means 0.5 <T / Tc <1.0 and 0.5 <P / Pc or 0.5 <T / Tc when the temperature is T (Centigrade) and the pressure is P. A state where <T / Tc and 0.5 <P / Pc <1.0 are satisfied. The preferred subcritical state is a condition of 0.6 <T / Tc <1.0 and 0.6 <P / Pc, or 0.6 <T / Tc and 0.6 <P / Pc <1.0. It is a state that satisfies. When the critical temperature Tc (Celsius) is negative, the temperature condition is satisfied. If the supercritical condition is not satisfied and the pressure condition of 0.5 <P / Pc is satisfied, the subcritical state is obtained. It shall be.

Examples of substances that generate a supercritical fluid or subcritical fluid include carbon dioxide, nitrogen, hydrogen, xenon, ethane, ammonia, methanol, and water. Of these, carbon dioxide and nitrogen are preferred.

Carbon dioxide has a critical temperature (Tc) of 31.1 ° C. and a critical pressure (Pc) of 7.38 MPa. Therefore, supercritical carbon dioxide is carbon dioxide in a state where the temperature T is 31.1 ° C. or higher and the pressure P is 7.38 MPa or higher. Subcritical carbon dioxide is carbon dioxide in a state satisfying the conditions of 15.6 ° C. <T <31.1 ° C. and 3.69 MPa <P, or 15.55 ° C. <T and 3.69 MPa <P <7.38 MPa. It is.

The critical temperature (Tc) of nitrogen is -147.0 ° C., and the critical pressure (Pc) is 3.40 MPa. Therefore, supercritical nitrogen is nitrogen in a state where the temperature T is -147.0 ° C. or higher and the pressure P is 3.40 MPa or higher. Subcritical nitrogen is nitrogen that does not satisfy the condition of supercritical nitrogen and satisfies the condition of 1.70 MPa <P.

The decompression speed is, for example, 5 to 10 MPa / s.

Kneading in the presence of a supercritical fluid or subcritical fluid can be performed by using a kneading apparatus in which a kneading member such as a rotor or screw is provided in a sealed rubber kneading chamber having excellent heat resistance and pressure resistance. it can. The kneading apparatus may be either a continuous system in which material supply and kneaded material recovery are performed continuously, or a batch system in which material supply and kneaded material recovery is performed once. Examples of the former include a biaxial extrusion kneader disclosed in JP-A-2002-355880. Examples of the latter include a kneader and a Banbury mixer.

In the kneading apparatus, when the cellulose fine fibers are kneaded and dispersed in the rubber component, the dispersion (gel) dispersed in the cellulose fine fiber water is converted into the rubber component kneaded with an open roll. Cellulose fine particles obtained by mixing and mixing a rubber latex with a master batch in which water is vaporized while mixing and kneading them, and a dispersion (gel) in which cellulosic fine fibers are dispersed in water. A master batch of fiber / rubber, a master of cellulose fine fiber / rubber obtained by mixing a dispersion obtained by dispersing cellulose fine fibers in a solvent and a solution obtained by dissolving a rubber component in a solvent and evaporating the solvent. Even if a batch, a dispersion (gel) in which cellulosic microfibers are dispersed in water is freeze-dried and pulverized, or cellulosic microfiber is hydrophobized, etc. There.

Then, the obtained porous uncrosslinked rubber composition is formed into a sheet shape by calendar molding or the like to produce an uncrosslinked rubber sheet 211a 'for the surface rubber layer.

Other methods are the same as those in the fourth embodiment.

[Embodiment 6]
(V-ribbed belt B)
FIG. 30 shows a V-ribbed belt B (power transmission belt) according to the sixth embodiment.

In the V-ribbed belt B according to Embodiment 6, the surface rubber layer 211a is made of an uncrosslinked rubber composition in which various rubber compounding agents are blended in the rubber component in addition to unexpanded hollow particles and cellulose fine fibers. It is formed of a rubber composition that is heated and pressurized and crosslinked with a crosslinking agent. In addition, the rubber composition forming the surface rubber layer 211a is formed with a large number of hollow portions 216b having shells inside due to expansion of the hollow particles and a large number of concave holes 217b having shells exposed on the surface. Porous rubber composition. In addition, the concave hole 217b having a shell is formed by expanding hollow particles whose surface breaks and opens the shell.

Examples of the unexpanded hollow particles blended in the uncrosslinked rubber composition before crosslinking of the rubber composition forming the surface rubber layer 211a include, for example, the inside of a shell formed of a thermoplastic polymer (for example, acrylonitrile-based polymer). And particles in which a solvent is encapsulated. The hollow particles may be mixed with a single type or with multiple types. The particle size of the unexpanded hollow particles is preferably 15 μm or more, more preferably 25 μm or more, and preferably 50 μm or less, more preferably 35 μm or less. The expansion start temperature of the hollow particles is preferably 140 ° C. or higher, more preferably 150 ° C. or higher, and preferably 180 ° C. or lower, more preferably 170 ° C. or lower. The blending amount of the hollow particles is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts per 100 parts by mass of the rubber component. 0.0 parts by mass or less. Examples of commercially available hollow particles include Sekisui Chemical Co., Ltd. trade name: ADVANCEL EM403 (particle size 26 to 34 μm, expansion start temperature: 150 to 170 ° C.).

The cellulose-based fine fiber has the same configuration as that of the fourth embodiment. The content of the cellulosic fine fiber with respect to 100 parts by mass of the rubber component in the rubber composition forming the surface rubber layer 211a may be larger or smaller than the blending amount of the hollow particles. It may be the same as the blending amount.

In addition to the unexpanded hollow particles, the foaming agent used in Embodiment 4 may also be blended in the uncrosslinked rubber composition before crosslinking of the rubber composition forming the surface rubber layer 211a. That is, in the rubber composition forming the surface rubber layer 211a, a large number of hollow portions 216b having shells are formed inside due to the expansion of the hollow particles, and a large number of concave holes 217b having shells exposed on the surface are formed. And a porous rubber composition in which a large number of hollow portions not having a shell are formed by foaming of a foaming agent and a plurality of concave holes having no shell exposed on the surface are formed. There may be.

In this case, the decomposition temperature of the foaming agent is preferably higher than the expansion start temperature of the hollow particles. Specifically, the decomposition temperature of the foaming agent is preferably 100 ° C. or more, more preferably 140 ° C. or more, and preferably 230 ° C. or less, more preferably 210 ° C. higher than the expansion start temperature of the hollow particles. It should be higher than ℃. The temperature difference between the expansion start temperature of the hollow particles and the decomposition temperature of the pyrolytic foaming agent is preferably 10 ° C or higher, more preferably 20 ° C or higher, and preferably 80 ° C or lower, more preferably 60 ° C or lower. It is.

The blending amount of the foaming agent with respect to 100 parts by mass of the rubber component is preferably larger than the blending amount of the hollow particles. The mass ratio of the blending amount of the blowing agent to the blending amount of the hollow particles (blending agent blending amount / hollow particle blending amount) is preferably 1 or more, more preferably 2.5 or more, and preferably 10 or less. More preferably, it is 8 or less.

The average hole diameter of the concave holes 217b on the surface of the surface rubber layer 211a reduces the difference in friction coefficient between the dry and wet surfaces of the surface rubber layer 211a, suppresses fluctuations in the friction coefficient over time, and From the viewpoint of suppressing the generation of abnormal noise, particularly abnormal noise when wet and the occurrence of slip when wet, it is preferably 70 μm or more, more preferably 80 μm or more, and preferably 120 μm or less, more preferably 110 μm or less. Here, the hole diameter of the recessed hole 217b is the opening diameter of the recessed hole 217b exposed on the surface of the surface rubber layer 211a, and the average hole diameter is obtained as the number average of 50 to 100 hole diameters measured from the surface image. be able to. In addition, the average hole diameter of the concave hole 217b can be controlled by the type and blending amount of the hollow particles.

Other configurations and operational effects are the same as those in the fourth embodiment.

(Manufacturing method of V-ribbed belt B)
In the manufacturing method of the V-ribbed belt B according to the sixth embodiment, the surface rubber layer 11a ′ in the material preparation process is manufactured as follows.

First, cellulosic fine fibers are put into a kneaded rubber component and dispersed by kneading.

Here, as a method for dispersing the cellulose-based fine fibers in the rubber component, for example, a dispersion (gel) in which the cellulose-based fine fibers are dispersed in water is added to the rubber component kneaded with an open roll, A method of vaporizing moisture while kneading them, a master of cellulose fine fibers / rubber obtained by mixing a dispersion (gel) in which cellulosic fine fibers are dispersed in water and rubber latex to vaporize the moisture Obtained by mixing the batch into a rubber component that has been masticated, mixing a dispersion in which cellulosic fine fibers are dispersed in a solvent, and a solution in which the rubber component is dissolved in the solvent, and evaporating the solvent. Cellulose fine fiber / rubber masterbatch is put into the kneaded rubber component, dispersion (gel) in which cellulose fine fiber is dispersed in water is freeze-dried and pulverized And what, how to put into a rubber component is masticated, methods and the like to introduce cellulosic microfibers made hydrophobic in rubber component is masticated.

Next, while kneading the rubber component and the cellulosic fine fibers, the hollow particles and various rubber compounding agents are added and kneading is continued.

Then, the obtained uncrosslinked rubber composition is molded into a sheet shape by calendar molding or the like to produce an uncrosslinked rubber sheet 211a 'for the surface rubber layer.

In the crosslinking step, the inner mold 231 expands, and the unmolded rubber sheet 211a ′ for the surface rubber layer in the laminated molded body B ′ is provided along the molding surface of the outer mold 232, and other uncrosslinked rubber is provided. The sheets 211b ′, 12 ′, and 13 ′ enter after being compressed, their cross-linking progresses and integrates, and the core wire 214 ′ is also combined and integrated, and further, an uncrosslinked rubber sheet for the surface rubber layer In 211a ′, the hollow particles expand, and finally, a cylindrical belt slab S is formed.

Other methods are the same as those in the fourth embodiment.

[Other Embodiments]
In Embodiments 4 to 3, the compression rubber layer 211 has a two-layer structure of a surface rubber layer 211a formed of a porous rubber composition and an inner rubber layer 211b formed of a solid rubber composition; However, the present invention is not particularly limited to this, and as shown in FIG. 31, the entire compressed rubber layer 211 may be composed of a single layer formed of a porous rubber composition.

In Embodiments 4 to 3, the V-ribbed belt B is used. However, the belt body is not particularly limited as long as it is a transmission belt in which at least a part of the belt body is formed of a porous rubber composition. A low edge V belt, a wrapped V belt, a flat belt, a toothed belt, or the like may be used.

[Test Evaluation 1]
(Flat belt)
A belt main body 210 as shown in FIG. 32 has a three-layer structure of an inner rubber layer 210a, an adhesive rubber layer 210b, and an outer rubber layer 210c, and a core wire 214 is embedded in the adhesive rubber layer 210b. The flat belt B of Examples 4-1 to 4-6 and Comparative examples 4-1 to 4-4 was prepared. Each configuration is also shown in Table 4.

<Example 4-1>
Mixing CR latex (made by Showa Denko Co., Ltd., trade name: Shoprene 842A) and an aqueous dispersion of cellulose fine fibers (made by Daio Paper Co., Ltd.) made of wood produced by mechanical defibrating means, and evaporating the water Thus, a master batch of cellulose fine fiber / CR was prepared.

Subsequently, CR (Showa Denko Co., Ltd., trade name: Showpren GS) was masticated, and a master batch was added thereto for kneading. The input amount of the masterbatch was such an amount that the content of cellulose fine fibers was 5 parts by mass when the total CR was 100 parts by mass.

Then, CR and cellulose fine fiber are kneaded, and there are 6 parts by mass of foaming agent (trade name: Cellmic CE, decomposition temperature: 208 ° C., manufactured by Sankyo Kasei Co., Ltd.) with respect to 100 parts by mass of CR. 40 parts by weight of black (trade name: Seast 3 manufactured by Tokai Carbon Co., Ltd.), 5 parts by weight of oil (trade name: Thamper 2280 manufactured by Nippon San Oil Co., Ltd.), zinc oxide as a vulcanization accelerator (manufactured by Sakai Chemical Industry Co., Ltd.) And 5 parts by mass of magnesium oxide (4 parts by mass of Kyowa Chemical Industry Co., Ltd., Kyowa Mug 150) were added, and kneading was continued to prepare an uncrosslinked rubber composition. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 11 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 45 parts by mass.

The uncrosslinked rubber composition was molded into a sheet to obtain an uncrosslinked rubber sheet for the inner rubber layer, and a flat belt of Example 4-1 was produced.

The adhesive rubber layer and the outer rubber layer were formed of a CR rubber composition, and a core wire was formed of aramid fiber twisted yarn that had been subjected to an adhesive treatment.

<Example 4-2>
The uncrosslinked rubber sheet for the inner rubber layer was the same as in Example 4-1, except that the carbon black and cellulose fine fiber contents were 10 parts by mass and 20 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 4-2 having the structure described above was produced. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 26 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 30 parts by mass.

<Example 4-3>
For the uncrosslinked rubber sheet for the inner rubber layer, cellulose fine fibers (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) made of wood produced by chemical defibration means (TEMPO oxidation treatment) are used as cellulose fine fibers, cellulose A flat belt of Example 4-3 having the same configuration as that of Example 4-1 was produced except that the content of fine fibers was 1 part by mass with respect to 100 parts by mass of the rubber component. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 7 parts by mass. The total content of cellulose fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 41 parts by mass.

<Example 4-4>
The uncrosslinked rubber sheet for the inner rubber layer was the same as in Example 4-3 except that the content of carbon black and cellulose fine fiber was 20 parts by mass and 5 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 4-4 having the structure described above was manufactured. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 11 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

<Example 4-5>
For the uncrosslinked rubber sheet for the inner rubber layer, the same as Example 4-3 except that the content of carbon black and cellulose fine fiber was 10 parts by mass and 10 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 4-4 having the structure described above was manufactured. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 16 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 20 parts by mass.

<Example 4-6>
Using a twin-screw extrusion kneader (manufactured by Nippon Steel Co., Ltd., model number: TEX30α), in the presence of supercritical carbon dioxide at a temperature of 100 ° C. and a pressure of 20 MPa, chemical defibration means ( 5 parts by mass of cellulose fine fibers made from wood produced by TEMPO oxidation treatment), 20 parts by mass of carbon black as a reinforcing material, 5 parts by mass of oil, 5 parts by mass of zinc oxide as a vulcanization accelerator, Then, 4 parts by mass of magnesium oxide was kneaded, and then the pressure was reduced to 7 MPa / s to prepare an uncrosslinked rubber composition. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

A flat belt of Example 4-6 having the same configuration as Example 4-1 was produced except that this uncrosslinked rubber composition was used as the uncrosslinked rubber sheet for the inner rubber layer.

<Comparative Example 4-1>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 4-1 having the same configuration as that of Example 4-1 was produced except that cellulose fine fibers were not contained.

<Comparative Example 4-2>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 4-2 having the same configuration as that of Example 4-1 was produced except that the foaming agent was not contained. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 45 parts by mass.

<Comparative Example 4-3>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 5-3 having the same configuration as that of Example 4-4 was produced except that the foaming agent was not contained. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

<Comparative Example 4-4>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 4-4 having the same configuration as that of Example 4-6 was produced except that cellulose fine fibers were not contained.

(Test evaluation method)
<Belt mass>
The belt mass of each of the flat belts of Example 4-1 to Example 4-6 and Comparative Example 4-1 to Comparative Example 4-4 was measured, and the belt mass of Comparative Example 2 that was the heaviest was assumed to be 1. Relative values were calculated.

<Average fiber diameter / fiber diameter distribution>
Samples of the inner rubber layer of each of the flat belts of Examples 4-1 to 4-6 were freeze pulverized, and the cross section was observed with a transmission electron microscope (TEM), and 50 cellulose fine fibers were observed. The fiber diameter was arbitrarily selected and the fiber diameter was measured. Moreover, the maximum value and minimum value of the fiber diameter were calculated | required among 50 cellulose fine fibers.

<Crack resistance evaluation belt running test>
FIG. 33 shows a belt running test machine 240 for evaluating crack resistance.

The crack running evaluation belt running test machine 240 includes a driving flat pulley 241 having a pulley diameter of 30 mm and a driven flat pulley 242 having a pulley diameter of 30 mm provided on the right side thereof. The driven flat pulley 242 is movably provided to the left and right so that an axial load (dead weight DW) can be applied to apply tension to the flat belt B.

For each flat belt B of Example 4-1 to Example 4-6 and Comparative Example 4-1 to Comparative Example 4-4, the driving flat pulley 241 and the driven flat pulley of the belt running test machine 240 for crack resistance evaluation The belt 242 is wound around, and a load of 600 N is applied to the right side of the driven flat pulley 242 to apply tension to the flat belt B, and the driving flat pulley 241 is rotated at 3000 rpm under an ambient temperature of 100 ° C. The belt was run by rotating. Then, the belt running was periodically stopped and whether or not the flat belt B was cracked was visually checked, and the belt running time until the occurrence of the crack was confirmed was defined as the crack occurrence life. In addition, when generation | occurrence | production of the crack was not recognized over 200 hours, the test was stopped at that time.

<High tension belt running test>
FIG. 34 shows a high tension belt running test machine 250.

The high tension belt running test machine 250 includes a driving flat pulley 251 having a pulley diameter of φ50 mm and a driven flat pulley 252 having a pulley diameter of 40 mm provided on the right side thereof. The driven flat pulley 252 is movably provided to the left and right so that a tension can be applied to the flat belt B by applying an axial load (dead weight DW).

About each flat belt B of Example 4-1 to Example 4-6 and Comparative Example 4-1 to Comparative Example 4-4, between the driving flat pulley 251 and the driven flat pulley 252 of the high tension belt running test machine 250. Winding, applying a shaft load of 500 N to the right side of the driven flat pulley 252 to give tension to the flat belt B, and rotating the driving flat pulley 251 at a rotational speed of 3000 rpm under an ambient temperature of 100 ° C. The belt was run by. Then, the belt running was stopped 100 hours after the start of running, the belt mass of the flat belt was measured, and the weight loss was determined as a percentage.

<Friction coefficient measurement test>
FIG. 35 shows a friction coefficient measuring device 260.

The friction coefficient measuring device 260 includes a flat pulley 261 having a pulley diameter of 60 mm and a load cell 262 provided on the side thereof. The flat pulley 261 is made of an iron-based material S45C. The test piece 263 of the flat belt is provided so that the flat belt 261 is wound around the flat pulley 261 after extending horizontally from the load cell 262, that is, the winding angle around the flat pulley 261 is 90 °.

The non-running flat belts of Example 4-1 to Example 4-6 and Comparative Example 4-1 to Comparative Example 4-4 were cut to produce a strip-shaped test piece 263, and one end of the load cell 262 was provided at one end. The weight 264 was attached to the other end and suspended. Subsequently, at an atmospheric temperature of 25 ° C., the flat pulley 261 is rotated at a rotation speed of 43 rpm in a direction in which the weight 264 is to be pulled down, and at 60 seconds after the rotation starts, the flat pulley 261 in the test piece 263 is loaded by the load cell 262. The tension Tt applied to the horizontal portion between the load cell 262 and the load cell 262 was measured. The tension Ts applied to the vertical portion of the flat pulley 261 and the weight 264 of the test piece 263 was 17.15 N corresponding to the weight of the weight 264. And based on Euler's formula, the friction coefficient μ at the time of drying the surface of the inner rubber layer was obtained by the following formula (1). Note that θ = π / 2.

Also, the flat belt after the high-tension belt running test was also subjected to the same test to determine the friction coefficient when the surface of the inner rubber layer was dried.

Further, the flat belt after the high tension belt running test was subjected to the same test with 5 ml of water interposed on the flat pulley 261, and the minimum value of the friction coefficient in 60 seconds from the start of rotation was obtained.

Then, the ratio of the friction coefficient at the time of drying after traveling to the friction coefficient at the time of drying without traveling (friction coefficient (after traveling) / friction coefficient (non-running)), and after the traveling with respect to the friction coefficient at the time of drying after traveling The ratio of the friction coefficient at the time of water intervention (friction coefficient (water intervention) / friction coefficient (dry)) was determined.

<Abnormal noise evaluation belt running test when wet>
FIG. 36 shows a pulley layout of a belt running test machine 270 for evaluating abnormal noise when wet.

The belt running test machine 270 for evaluating abnormal noise when wet is a driving flat pulley 271 having a pulley diameter of 140 mm, a first driven flat pulley 272 having a pulley diameter of 75 mm provided on the right side of the driving flat pulley 271, Provided above the first driven flat pulley 272 and obliquely above the driving flat pulley 271 to the right between the second driven flat pulley 273 with a pulley diameter of 50 mm, and between the driving flat pulley 271 and the second driven flat pulley 273. And an idler pulley 274 having a pulley diameter of 75 mm. In this belt running test machine 270 for evaluating abnormal noise when wet, the inner rubber layer of the flat belt B contacts the driving flat pulley 271, the first and second driven flat pulleys 72, 73, and the outer rubber layer It is configured to be wound around in contact with the idler pulley 274.

For each flat belt B of Example 4-1 to Example 4-6 and Comparative Example 4-1 to Comparative Example 4-4, the driving flat pulley 271 of the belt running test machine 270 for evaluating abnormal noise when wet, The pulleys are wound around the first and second driven flat pulleys 72 and 73 and the idler pulley 274 and positioned so that a belt tension of 300 N is applied, and the second driven flat pulley 273 is attached to an alternator attached to the pulley A resistance was applied so that a current of 1 mm flows, and the belt was run by rotating the driving pulley 271 at a rotation speed of 800 rpm at room temperature. At this time, water was dropped at a rate of 1000 ml per minute on the inner rubber layer side of the flat belt B at the portion where the flat belt B entered the driving flat pulley 271. And the abnormal noise generation | occurrence | production situation at the time of belt running was evaluated in four steps, large, small, minute, and nothing.

(Test evaluation results)
The test results are shown in Table 4.

According to Table 4, it can be seen that the cellulose fine fibers of Examples 4-1 to 4-6 all have a wide fiber diameter distribution.

In Examples 4-1 to 4-6, in which the inner rubber layer was formed of a porous rubber composition containing cellulose fine fibers, the weight was reduced by using the porous rubber composition, and It can be seen that the rubber layer has a crack generation life equivalent to that of Comparative Example 4-2 and Comparative Example 4-3 formed of a solid rubber composition. In Examples 4-1 to 4-6, the mass loss after the high-tension belt running test is small, so that the wear resistance is high, the change of the coefficient of friction with time is small, and when the water is interposed. Since the difference in the coefficient of friction during drying is small, the coefficient of friction is stable, and even when water is poured during running of the belt, no abnormal noise is observed, so that it can be seen that the belt has excellent belt performance.

On the other hand, in Comparative Example 4-1 and Comparative Example 4-4 in which the inner rubber layer was formed of a porous rubber composition not containing fine cellulose fibers, weight reduction was achieved by using the porous rubber composition, Although the friction coefficient is stable and no abnormal noise is observed even when water is poured during belt running, the wear resistance is inferior due to the large weight loss after the high tension belt running test, and the crack generation life is also short. It can be seen that it is extremely short.

Further, Comparative Example 4-2 and Comparative Example 4-3, in which the inner rubber layer was formed of a solid rubber composition containing cellulose fine fibers, had high wear resistance and a long crack generation life, but the friction coefficient It can be seen that this is inferior to Examples 4-1 to 4-6 in terms of stability and that abnormal noise is observed when water is poured during belt running.

(Flat belt)
A belt main body 210 as shown in FIG. 32 has a three-layer structure of an inner rubber layer 210a, an adhesive rubber layer 210b, and an outer rubber layer 210c, and a core wire 214 is embedded in the adhesive rubber layer 210b. The flat belts of Examples 5-1 to 5-6 and Comparative Examples 5-1 to 5-4 were prepared. Each configuration is also shown in Table 5.

<Example 5-1>
H-NBR latex (trade name: ZLX-B manufactured by Nippon Zeon Co., Ltd.) is mixed with an aqueous dispersion of cellulose fine fibers made from wood produced by mechanical defibration means, and water is evaporated to make fine cellulose fines. A fiber / H-NBR masterbatch was prepared.

Subsequently, H-NBR (manufactured by Nippon Zeon Co., Ltd., trade name: Zetpol® 2020) was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the cellulose fine fiber content was 5 parts by mass when the total H-NBR was 100 parts by mass.

Then, H-NBR and fine cellulose fibers are kneaded, and there are 7 parts by mass of a foaming agent, 40 parts by mass of carbon black as a reinforcing material, 10 parts by mass of oil, 100 parts by mass of H-NBR. 5 parts by weight of organic peroxide (manufactured by NOF Corporation, trade name: Peroximon F40, active ingredient 40% by mass) and co-crosslinking agent (trade name: High Cloth M, manufactured by Seiko Chemical Co., Ltd.) 1 part by mass of each was added and kneading was continued to prepare an uncrosslinked rubber composition. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 12 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 45 parts by mass.

The uncrosslinked rubber composition was molded into a sheet to obtain an uncrosslinked rubber sheet for the inner rubber layer, and a flat belt of Example 5-1 was produced.

Note that the adhesive rubber layer and the outer rubber layer were formed of an H-NBR rubber composition, and a core wire was formed of an aramid fiber twisted yarn subjected to an adhesive treatment.

<Example 5-2>
The uncrosslinked rubber sheet for the inner rubber layer was the same as in Example 5-1, except that the carbon black and cellulose fine fiber contents were 10 parts by mass and 20 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 5-2 having the structure described above was produced. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 27 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 30 parts by mass.

<Example 5-3>
For the uncrosslinked rubber sheet for the inner rubber layer, cellulose fine fibers produced by chemical defibration means (TEMPO oxidation treatment) are used as the cellulose fine fibers, and the content of the cellulose fine fibers is 100 parts by mass of the rubber component. A flat belt of Example 5-3 having the same configuration as that of Example 5-1 was prepared except that the amount was 1 part by mass. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 8 parts by mass. The total content of cellulose fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 41 parts by mass.

<Example 5-4>
For the uncrosslinked rubber sheet for the inner rubber layer, the same as Example 5-3 except that the content of carbon black and cellulose fine fiber was 20 parts by mass and 5 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 5-4 having the structure as described above was manufactured. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 12 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

<Example 5-5>
For the uncrosslinked rubber sheet for the inner rubber layer, the same as Example 5-3 except that the content of carbon black and cellulose fine fiber was 10 parts by mass and 10 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 5-4 having the structure as described above was manufactured. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 17 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 20 parts by mass.

<Example 5-6>
Manufactured by chemical defibration means (TEMPO oxidation treatment) for H-NBR and 100 parts by mass of H-NBR in the presence of supercritical carbon dioxide at a temperature of 100 ° C and a pressure of 20 MPa using a twin-screw extrusion kneader. 5 parts by mass of cellulose fine fiber made from the finished wood, 20 parts by mass of carbon black as a reinforcing material, 10 parts by mass of oil, 5 parts by mass of organic peroxide as a crosslinking agent, and 1 part by mass of a co-crosslinking agent Then, the pressure was reduced to 7 MPa / s to prepare an uncrosslinked rubber composition. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

A flat belt of Example 5-6 having the same configuration as Example 5-1 was produced except that this uncrosslinked rubber composition was used as an uncrosslinked rubber sheet for the inner rubber layer.

<Comparative Example 5-1>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 5-1 having the same configuration as that of Example 5-1 was produced except that cellulose fine fibers were not contained.

<Comparative Example 5-2>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 5-2 having the same configuration as that of Example 5-1 was produced except that the foaming agent was not contained. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 45 parts by mass.

<Comparative Example 5-3>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 5-3 having the same configuration as that of Example 5-4 was produced except that the foaming agent was not contained. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

<Comparative Example 5-4>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 5-4 having the same constitution as that of Example 5-6 was produced except that cellulose fine fibers were not contained.

(Test evaluation method)
For each flat belt of Examples 5-1 to 5-6, the average fiber diameter and fiber diameter distribution of the fine cellulose fibers were determined in the same manner as in Example 4. Further, for each flat belt of Example 5-1 to Example 5-6 and Comparative Example 5-1 to Comparative Example 5-4, the belt mass was measured in the same manner as in Example 4 to obtain Comparative Example 4-2. In addition to relative evaluation as a reference, a crack resistance evaluation belt running test, a high-tension belt running test, a friction coefficient measurement test, and an abnormal noise evaluation belt running test when wet were performed. In the crack resistance evaluation belt running test and the high tension belt running test, the ambient temperature was set to 120 ° C.

(Test evaluation results)
The test results are shown in Table 5.

According to Table 5, it can be seen that the same results as in Example 4 were obtained even when the rubber component was H-NBR.

(Flat belt)
A belt main body 210 as shown in FIG. 32 has a three-layer structure of an inner rubber layer 210a, an adhesive rubber layer 210b, and an outer rubber layer 210c, and a core wire 214 is embedded in the adhesive rubber layer 210b. The flat belts of Examples 6-1 to 6-6 and Comparative Examples 6-1 to 6-4 were prepared. Each configuration is also shown in Table 6.

<Example 6-1>
A dispersion in which fine cellulose fibers produced by mechanical defibrating means are dispersed in toluene and a solution in which EPDM (trade name: EP33 manufactured by JSR) is dissolved in toluene are mixed, and toluene is vaporized to mix cellulose. A fine fiber / EPDM masterbatch was prepared.

Next, EPDM was masticated, and a master batch was added thereto for kneading. The input amount of the master batch was such that the cellulose fine fiber content was 5 parts by mass when the total EPDM was 100 parts by mass.

Then, EPDM and fine cellulose fibers are kneaded, and there are 7 parts by mass of a foaming agent, 40 parts by mass of carbon black as a reinforcing material, 10 parts by mass of oil and 100% by mass of an organic solvent of a crosslinking agent. An uncrosslinked rubber composition was prepared by adding 5 parts by mass of an oxide and 1 part by mass of a co-crosslinking agent and continuing kneading. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 12 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 45 parts by mass.

The uncrosslinked rubber composition was molded into a sheet to obtain an uncrosslinked rubber sheet for the inner rubber layer, and a flat belt of Example 6-1 was produced.

The adhesive rubber layer and the outer rubber layer were formed of an EPDM rubber composition, and the core wire was formed of aramid fiber twisted yarn subjected to an adhesive treatment.

<Example 6-2>
The uncrosslinked rubber sheet for the inner rubber layer was the same as Example 6-1 except that the content of carbon black and cellulose fine fiber was 10 parts by mass and 20 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 6-2 having the structure described above was produced. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 27 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 30 parts by mass.

<Example 6-3>
For the uncrosslinked rubber sheet for the inner rubber layer, cellulose fine fibers produced by chemical defibration means (TEMPO oxidation treatment) are used as the cellulose fine fibers, and the content of the cellulose fine fibers is 100 parts by mass of the rubber component. A flat belt of Example 6-3 having the same configuration as that of Example 6-1 was prepared except that the amount was 1 part by mass. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 8 parts by mass. The total content of cellulose fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 41 parts by mass.

<Example 6-4>
The uncrosslinked rubber sheet for the inner rubber layer was the same as Example 6-3 except that the content of carbon black and cellulose fine fiber was 20 parts by mass and 5 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 6-4 having the structure described above was manufactured. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 12 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

<Example 6-5>
For the uncrosslinked rubber sheet for the inner rubber layer, the same as Example 6-3 except that the content of carbon black and cellulose fine fiber was 10 parts by mass and 10 parts by mass with respect to 100 parts by mass of the rubber component, respectively. A flat belt of Example 6-4 having the structure described above was manufactured. The total content of the foaming agent and cellulose fine fiber with respect to 100 parts by mass of the rubber component is 17 parts by mass. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 20 parts by mass.

<Example 6-6>
Cellulose finely produced by chemical defibrating means (TEMPO oxidation treatment) for EPDM and 100 parts by mass of EPDM in the presence of supercritical carbon dioxide at a temperature of 100 ° C. and a pressure of 20 MPa using a biaxial extrusion kneader. 5 parts by mass of fiber, 20 parts by mass of carbon black as a reinforcing material, 10 parts by mass of oil, 5 parts by mass of organic peroxide as a crosslinking agent, and 1 part by mass of a co-crosslinking agent are kneaded, and then the pressure is reduced. An uncrosslinked rubber composition was produced by reducing the pressure at a rate of 7 MPa / s. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

A flat belt of Example 6-6 having the same configuration as Example 6-1 was produced except that this uncrosslinked rubber composition was used as an uncrosslinked rubber sheet for the inner rubber layer.

<Comparative Example 6-1>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 6-1 having the same configuration as that of Example 6-1 was produced except that cellulose fine fibers were not contained.

<Comparative Example 6-2>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 6-2 having the same configuration as that of Example 6-1 was produced except that the foaming agent was not contained. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 45 parts by mass.

<Comparative Example 6-3>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 6-3 having the same configuration as that of Example 6-4 was produced except that the foaming agent was not contained. The total content of cellulose-based fine fibers and carbon black with respect to 100 parts by mass of the rubber component is 25 parts by mass.

<Comparative Example 6-4>
For the uncrosslinked rubber sheet for the inner rubber layer, a flat belt of Comparative Example 6-4 having the same configuration as that of Example 6-6 was prepared except that cellulose fine fibers were not contained.

(Test evaluation method)
For each flat belt of Examples 6-1 to 6-6, the average fiber diameter and fiber diameter distribution of the fine cellulose fibers were determined in the same manner as in Example 4. Further, for each of the flat belts of Example 6-1 to Example 6-6 and Comparative Example 6-1 to Comparative Example 6-4, the belt mass was measured in the same manner as in Example 4 to obtain Comparative Example 6-2. In addition to relative evaluation as a reference, a crack resistance evaluation belt running test, a high-tension belt running test, a friction coefficient measurement test, and an abnormal noise evaluation belt running test when wet were performed. In the crack resistance evaluation belt running test and the high tension belt running test, the ambient temperature was set to 120 ° C.

(Test evaluation results)
The test results are shown in Table 6.

According to Table 6, it can be seen that the same results as in Example 4 and Example 5 were obtained even when the rubber component was EPDM.

[Embodiment 7]
(Toothed belt B)
FIG. 37 shows a toothed belt B according to the seventh embodiment.

The toothed belt B according to Embodiment 7 includes an endless toothed belt body 310 formed of a rubber composition. The toothed belt main body 310 includes a flat belt-like base portion 311a and a plurality of tooth portions 311b that are integrally provided at a constant pitch at intervals in the belt length direction on one side, that is, the inner peripheral surface. Have. A tooth side reinforcing cloth 312 is attached to the toothed belt main body 310 so as to cover the tooth side surface thereof. A core wire 313 is embedded on the inner peripheral side of the base 311a of the toothed belt main body 310 so as to form a spiral having a pitch in the belt width direction. The toothed belt B according to the seventh embodiment is suitably used as a power transmission member of, for example, a belt transmission device in a machine tool or the like, in particular, a belt transmission device in a machine tool having an operation time of about 3 to 120 hours per year. The toothed belt B according to Embodiment 7 has, for example, a belt length of 500 to 3000 mm, a belt width of 10 to 200 mm, and a belt thickness of 3 to 20 mm. Further, the tooth portion 311b has, for example, a width of 0.63 to 16.46 mm, a height of 0.37 to 9.6 mm, and a pitch of 1.0 to 31.75 mm.

The tooth portion 311b of the toothed belt main body 310 may be a trapezoidal tooth having a trapezoidal shape when viewed from the side, may be a semicircular round tooth, and may have other shapes. Good. The tooth portion 311b may be formed so as to extend in the belt width direction, or may be a helical tooth formed so as to extend in a direction inclined with respect to the belt width direction.

In the toothed belt main body 310, an uncrosslinked rubber composition obtained by mixing and kneading various rubber compounding agents in addition to cellulose fine fibers containing a fiber diameter distribution range of 50 to 500 nm in a rubber component is heated and added. It is formed of a rubber composition that is pressed and crosslinked with a crosslinking agent. As described above, the rubber composition forming the toothed belt body 310 contains the cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm, whereby the durability of the toothed belt B can be improved. . Here, “fine fiber” in the present application means a fiber having a fiber diameter of 1.0 μm or less.

Examples of the rubber component of the rubber composition forming the toothed belt main body 310 include hydrogenated acrylonitrile rubber (H-NBR), hydrogenated acrylonitrile rubber reinforced with unsaturated carboxylic acid metal salt (H-NBR), ethylene, and the like. -Ethylene-α-olefin elastomers such as propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer, chloroprene rubber (CR), and chlorosulfonated polyethylene rubber (CSM) ) And the like. The rubber component of the rubber composition forming the toothed belt main body 310 is preferably a blend rubber of one or more of these.

In H-NBR reinforced with an unsaturated carboxylic acid metal salt, examples of the unsaturated carboxylic acid include methacrylic acid and acrylic acid, and examples of the metal include zinc, calcium, magnesium, aluminum and the like. Is mentioned.

Cellulosic fine fiber is a fiber material derived from cellulose fine fiber composed of a skeletal component of a plant cell wall obtained by finely loosening plant fiber. Examples of the cellulosic fine fiber plant include wood, bamboo, rice (rice straw), potato, sugar cane (bagasse), aquatic plants, seaweed and the like. Of these, wood is preferred.

The cellulose-based fine fiber may be either the cellulose fine fiber itself or a hydrophobic cellulose fine fiber that has been subjected to a hydrophobic treatment. Moreover, you may use together cellulose fine fiber itself and hydrophobized cellulose fine fiber as a cellulosic fine fiber. From the viewpoint of dispersibility, the cellulosic fine fibers preferably include hydrophobized cellulose fine fibers. Examples of the hydrophobized cellulose fine fibers include cellulose fine fibers in which some or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups, and cellulose fine fibers that have been subjected to a hydrophobized surface treatment with a surface treatment agent.

Examples of hydrophobization for obtaining cellulose fine fibers in which part or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups include esterification (acylation) (alkyl esterification, complex esterification, β-ketoesterification, etc.) ), Alkylation, tosylation, epoxidation, arylation and the like. Of these, esterification is preferred. Specifically, in the esterified hydrophobized cellulose fine fiber, part or all of the hydroxyl groups of cellulose are carboxylic acids such as acetic acid, acetic anhydride, propionic acid, butyric acid, or halides thereof (particularly chlorides). It is the cellulose fine fiber acylated by. Examples of the surface treatment agent for obtaining cellulose fine fibers hydrophobized and surface-treated with the surface treatment agent include silane coupling agents.

The cellulosic fine fibers preferably have a wide fiber diameter distribution from the viewpoint of improving the durability of the toothed belt B, and the fiber diameter distribution range includes 50 to 500 nm. From the viewpoint, the lower limit of the fiber diameter distribution is preferably 20 nm or less, more preferably 10 nm or less. From the same viewpoint, the upper limit is preferably 700 nm or more, more preferably 1 μm or more. The fiber diameter distribution range of the cellulosic fine fibers preferably includes 20 nm to 700 mm, and more preferably includes 10 nm to 1 μm.

The average fiber diameter of the cellulosic fine fibers contained in the rubber composition forming the toothed belt body 310 is preferably 10 nm or more, more preferably 20 nm or more, and preferably 700 nm or less, more preferably 100 nm or less. It is.

The distribution of the fiber diameter of the cellulosic fine fibers was determined by freeze-grinding a sample of the rubber composition forming the toothed belt main body 310, and then observing the cross section with a transmission electron microscope (TEM). A fine fiber is arbitrarily selected, the fiber diameter is measured, and obtained based on the measurement result. The average fiber diameter of the cellulosic fine fibers is obtained as the number average of the fiber diameters of 50 arbitrarily selected cellulosic fine fibers.

The cellulosic fine fibers may be either high aspect ratio manufactured by mechanical defibrating means, or needle-shaped crystals manufactured by chemical defibrating means. Of these, those manufactured by mechanical defibrating means are preferred. Moreover, you may use together what was manufactured by the mechanical defibration means, and what was manufactured by the chemical defibration means as a cellulose fine fiber. Examples of the defibrating apparatus used for the mechanical defibrating means include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a grinder, and a bead mill. Examples of the treatment used for the chemical defibrating means include acid hydrolysis treatment.

From the viewpoint of improving the durability of the toothed belt B, the content of the cellulosic fine fibers in the rubber composition forming the toothed belt body 310 is preferably 1 part by weight or more with respect to 100 parts by weight of the rubber component. More preferably, it is 3 parts by mass or more, more preferably 5 parts by mass or more, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and still more preferably 10 parts by mass or less.

Examples of rubber compounding agents include reinforcing materials, processing aids, vulcanization acceleration aids, plasticizers, co-crosslinking agents, crosslinking agents, vulcanization accelerators, anti-aging agents, and the like.

As the reinforcing material, carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like. Silica is also mentioned as the reinforcing material. It is preferable that a reinforcing material is 1 type, or 2 or more types among these. The content of the reinforcing material is, for example, 20 to 60 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of processing aids include stearic acid, polyethylene wax, and fatty acid metal salts. Among these, the processing aid is preferably one or more. The content of the processing aid is, for example, 0.5 to 2 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the vulcanization acceleration aid include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof. Among these, the vulcanization acceleration aid is preferably one or more. The content of the vulcanization acceleration aid is, for example, 3 to 7 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the plasticizer include dialkyl phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), dialkyl adipates such as dioctyl adipate (DOA), and dialkyl sebacates such as dioctyl sebacate (DOS). It is preferable that a plasticizer is 1 type, or 2 or more types among these. The plasticizer content is, for example, 0.1 to 40 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the co-crosslinking agent include liquid rubber such as liquid NBR. The co-crosslinking agent is preferably one type or two or more types. The content of the co-crosslinking agent is, for example, 3 to 7 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be blended, an organic peroxide may be blended, or both of them may be used in combination. The amount of the crosslinking agent is, for example, 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, and 100 parts by mass of the rubber component of the rubber composition with respect to the organic peroxide. For example, 1 to 5 parts by mass.

Examples of the vulcanization accelerator include thiuram (eg, TETD, TT, TRA, etc.), thiazole (eg, MBT, MBTS, etc.), sulfenamide (eg, CZ), dithiocarbamate (eg, BZ-P). Etc.). It is preferable that a vulcanization accelerator is 1 type, or 2 or more types among these. The content of the vulcanization accelerator is, for example, 2 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the anti-aging agent include amine-ketone anti-aging agents, diamine anti-aging agents, phenol anti-aging agents and the like. It is preferable that an anti-aging agent is 1 type, or 2 or more types among these. The content of the anti-aging agent is, for example, 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component.

Note that the rubber composition forming the toothed belt main body 310 may contain short fibers having a fiber diameter of 10 μm or more.

The tooth part side reinforcing cloth 312 is made of a cloth material such as a woven fabric, a knitted fabric, or a non-woven fabric formed of yarns such as cotton, polyamide fiber, polyester fiber, and aramid fiber. It is preferable that the tooth part side reinforcing cloth 312 has extensibility. The thickness of the tooth side reinforcing cloth 312 is, for example, 0.3 to 2.0 mm. The tooth part side reinforcing cloth 312 is subjected to an adhesion process for adhesion to the toothed belt main body 310.

The core wire 313 is composed of a twisted yarn formed of glass fiber, aramid fiber, polyamide fiber, polyester fiber or the like. The diameter of the core wire 313 is, for example, 0.5 to 2.5 mm, and the dimension between adjacent core wire centers in the cross section is, for example, 0.05 to 0.20 mm. The core wire 313 is subjected to an adhesive treatment for imparting adhesiveness to the toothed belt main body 310.

According to the toothed belt B according to the seventh embodiment having the above-described configuration, the rubber composition forming the toothed belt main body 310 including the base portion 311a and the tooth portion 311b includes cellulose having a fiber diameter distribution range of 50 to 500 nm. By containing the system fine fiber, its excellent reinforcing effect can be obtained, and in particular, chipping of the tooth portion 311b can be suppressed, and excellent oil resistance can be obtained, and as a result, high durability can be obtained. it can.

(Manufacturing method of toothed belt B)
A method for manufacturing the toothed belt B according to the seventh embodiment will be described with reference to FIGS.

FIG. 38 shows a belt forming die 320 used for manufacturing the toothed belt B according to the seventh embodiment.

The belt forming die 320 has a cylindrical shape, and tooth portion forming grooves 321 extending in the axial direction are formed on the outer peripheral surface thereof at a constant pitch with an interval in the circumferential direction.

The manufacturing method of the toothed belt according to the seventh embodiment includes a material preparation process, a molding process, a crosslinking process, and a finishing process.

<Material preparation process>
-Uncrosslinked rubber sheet 311 'for base and teeth-
First, cellulosic fine fibers are put into a kneaded rubber component and dispersed by kneading.

Here, as a method for dispersing the cellulose-based fine fibers in the rubber component, for example, a dispersion (gel) in which the cellulose-based fine fibers are dispersed in water is added to the rubber component kneaded with an open roll, A method of vaporizing moisture while kneading them, a master of cellulose fine fibers / rubber obtained by mixing a dispersion (gel) in which cellulosic fine fibers are dispersed in water and rubber latex to vaporize the moisture Obtained by mixing the batch into a rubber component that has been masticated, mixing a dispersion in which cellulosic fine fibers are dispersed in a solvent, and a solution in which the rubber component is dissolved in the solvent, and evaporating the solvent. Cellulose fine fiber / rubber masterbatch is put into the kneaded rubber component, dispersion (gel) in which cellulose fine fiber is dispersed in water is freeze-dried and pulverized And what, how to put into a rubber component is masticated, methods and the like to introduce cellulosic microfibers made hydrophobic in rubber component is masticated.

Next, while kneading the rubber component and the cellulosic fine fiber, various rubber compounding agents are added and kneading is continued.

Then, the obtained uncrosslinked rubber composition is formed into a sheet shape by calendar molding or the like to produce an uncrosslinked rubber sheet 311 'for the base and teeth.

-Tooth side reinforcing cloth 312'-
Adhesive treatment is applied to the tooth side reinforcing cloth 312 ′. Specifically, the tooth side reinforcing cloth 312 ′ is subjected to an RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated. Further, if necessary, a base adhesion treatment in which the substrate is immersed in a base adhesion treatment solution and heated is performed before the RFL adhesion treatment. In addition, if necessary, a soaking rubber paste bonding treatment that is immersed in rubber paste after the RFL bonding treatment and / or drying, and / or a coating rubber paste that is coated with rubber paste on the surface on the toothed belt body 310 side and dried. Apply adhesive treatment.

Next, both ends of the tooth side reinforcing cloth 312 ′ subjected to the adhesion treatment are joined to form a cylindrical shape.

-Core 313'-
An adhesive treatment is applied to the core wire 313 ′. Specifically, the core wire 313 ′ is subjected to an RFL adhesion treatment in which it is immersed in a resorcin / formalin / latex aqueous solution (hereinafter referred to as “RFL aqueous solution”) and heated. In addition, if necessary, a base adhesive treatment in which the substrate is immersed in a base adhesive treatment solution and heated before the RFL adhesive treatment and / or a rubber paste adhesive treatment in which the RFL adhesive treatment is immersed in rubber paste and dried are performed.

<Molding process>
As shown in FIG. 39, a cylindrical tooth portion side reinforcing cloth 312 ′ is placed on the outer periphery of the belt mold 320, and a core wire 313 ′ is spirally wound thereon, and further, an uncrosslinked rubber sheet 311 ′ is wound thereon. Wrap. At this time, a laminated molded body B ′ is formed on the belt mold 320. The uncrosslinked rubber sheet 311 ′ may be used so that the line direction corresponds to the belt length direction, or the line direction may correspond to the belt width direction. .

<Crosslinking process>
As shown in FIG. 40, after the release paper 322 is wound around the outer periphery of the laminated molded body B ′, a rubber sleeve 323 is placed on the outer periphery, and the rubber sleeve 323 is placed and sealed in the vulcanizing can. Is filled with high-temperature and high-pressure steam and held for a predetermined molding time. At this time, the uncrosslinked rubber sheet in the laminated molded body B ′ flows while pressing the tooth portion side reinforcing cloth 312 ′ and flows into the tooth portion forming groove 321 of the belt forming die 320, and the crosslinking proceeds, And the tooth part side reinforcing cloth 312 ′ and the core wire 313 ′ are combined and integrated, and finally, a cylindrical belt slab S is formed as shown in FIG. The molding temperature of the belt slab S is, for example, 100 to 180 ° C., the molding pressure is, for example, 0.5 to 2.0 MPa, and the molding time is, for example, 10 to 60 minutes.

<Finishing process>
The inside of the vulcanizing can is depressurized to release the seal, the belt slab S molded between the belt mold 320 and the rubber sleeve 323 is taken out and demolded, and the back side is polished to adjust the thickness. After that, the toothed belt B is manufactured by cutting into a predetermined width.

[Embodiment 8]
(Toothed belt B)
Since the external configuration of the toothed belt B according to the eighth embodiment is the same as that of the seventh embodiment, a description will be given below based on FIG.

In the toothed belt B according to Embodiment 8, the rubber composition forming the base 311a in the toothed belt main body 310 contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. On the other hand, the rubber composition forming the tooth portion 311b does not contain such cellulosic fine fibers. The rubber composition forming the tooth portion 311b may contain cellulosic fine fibers whose fiber diameter distribution range does not include 50 to 500 nm.

Other configurations are the same as those in the seventh embodiment.

According to the toothed belt B according to the eighth embodiment having the above-described configuration, the rubber composition forming the base portion 311a is superior in that it contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. The reinforcing effect can be obtained, and excellent oil resistance can be obtained. As a result, high durability can be obtained.

(Manufacturing method of toothed belt B)
In the manufacturing method of the toothed belt B according to Embodiment 8, in the material preparation step, as in Embodiment 7, the base uncrosslinked rubber sheet containing cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm is used. 311a ′ is produced. In addition, uncrosslinked rubber containing no cellulosic fine fiber having a fiber diameter distribution range of 50 to 500 nm obtained by blending various rubber compounding agents with a rubber component and kneading with a kneader such as a kneader or Banbury mixer. An uncrosslinked rubber 311 b ′ for a tooth part, in which the composition is formed in the shape of the tooth part forming groove 321 of the belt mold 320, is prepared.

Then, in the molding step, as shown in FIG. 42, the outer periphery of the belt mold 320 is covered with a cylindrical tooth side reinforcing cloth 312 ′ and along the tooth part forming groove 321, and then, as shown in FIG. Into each tooth portion forming groove 321, uncrosslinked rubber 311 b ′ for teeth is inserted, and as shown in FIG. 44, a core wire 313 ′ is spirally wound from above, and further, uncrosslinked for base is formed from above. A laminated molded body B ′ is formed by winding the rubber sheet 311a ′. In the cross-linking step, cross-linking of the uncrosslinked rubber 311b ′ for teeth and the uncrosslinked rubber sheet 311a ′ for base in the laminated molded body B ′ proceeds, and the tooth side reinforcing cloth 312 ′ and the core wire 313 ′. Are combined and integrated, and finally, a cylindrical belt slab S similar to that shown in FIG. 41 in the seventh embodiment is formed.

Other methods are the same as those in the seventh embodiment.

[Embodiment 9]
(Toothed belt B)
Since the external configuration of the toothed belt B according to the ninth embodiment is the same as that of the seventh embodiment, the following description is based on FIG.

In the toothed belt B according to Embodiment 9, the rubber composition forming the tooth portion 311b in the toothed belt main body 310 contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. On the other hand, the rubber composition forming the base 311a does not contain such cellulosic fine fibers. Note that the rubber composition forming the base 311a may contain cellulosic fine fibers whose fiber diameter distribution range does not include 50 to 500 nm.

Other configurations are the same as those in the seventh embodiment.

According to the toothed belt B according to the ninth embodiment having the above configuration, the rubber composition forming the tooth portion 311b contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. An excellent reinforcing effect can be obtained, in particular, chipping of the tooth portion 311b can be suppressed, and excellent oil resistance can be obtained. As a result, high durability can be obtained.

(Manufacturing method of toothed belt B)
In the manufacturing method of the toothed belt B according to the ninth embodiment, in the material preparation step, as in the seventh embodiment, the uncrosslinked rubber for a tooth portion containing cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm, as in the seventh embodiment. The composition is kneaded, and an uncrosslinked rubber 311 b ′ for the tooth portion, which is formed into the shape of the tooth portion forming groove 321 of the belt mold 320, is produced. Further, by blending various rubber compounding agents with the rubber component and kneading with a kneader such as a kneader or a Banbury mixer, the uncrosslinked rubber composition not containing such cellulosic fine fibers is formed into a sheet by calendar molding or the like. An uncrosslinked rubber sheet 311a ′ for the base is formed by molding.

Then, in the molding step, as shown in FIG. 42 in the eighth embodiment, after covering the outer periphery of the belt mold 320 with the cylindrical tooth side reinforcing cloth 312 ′ and along the tooth part forming groove 321, In the same manner as shown in FIG. 43, uncrosslinked rubber 311b ′ for the tooth portion is fitted into each tooth portion forming groove 321, and the core wire 313 ′ is spirally wound from above as shown in FIG. Further, a laminated molded body B ′ is formed by winding an uncrosslinked rubber sheet 311a ′ for the base portion thereon. In the cross-linking step, cross-linking of the uncrosslinked rubber 311b ′ for teeth and the uncrosslinked rubber sheet 311a ′ for base in the laminated molded body B ′ proceeds, and the tooth side reinforcing cloth 312 ′ and the core wire 313 ′. Are combined and integrated, and finally, a cylindrical belt slab S similar to that shown in FIG. 41 in the seventh embodiment is formed.

Other methods are the same as those in the seventh embodiment.

[Embodiment 10]
(Toothed belt B)
Since the external configuration of the toothed belt B according to the tenth embodiment is the same as that of the seventh embodiment, the following description is based on FIG.

In the toothed belt B according to the tenth embodiment, the tooth portion side reinforcing cloth 312 is subjected to an RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated. Thereby, as shown in FIG. 45, the tooth side reinforcing cloth 312 is bonded to the toothed belt main body 310 via the RFL bonding layer 314 formed by the RFL bonding process. In addition, before the RFL adhesion treatment, a foundation adhesion treatment comprising a solution obtained by dissolving a foundation adhesion treatment agent such as an epoxy resin or an isocyanate resin (block isocyanate) in a solvent such as toluene, or a dispersion liquid dispersed in water. It is preferable that a base adhesion treatment in which the substrate is immersed in a liquid and heated is performed, and a base adhesive layer is provided under the RFL adhesive layer 314. Further, after RFL adhesion treatment, one kind of soaking rubber glue adhesion treatment that is immersed in rubber glue and dried, and coating rubber glue adhesion treatment that coats and drys the rubber glue on the surface on the toothed belt body 310 side Alternatively, two types of rubber glue adhesion treatment may be performed, and a rubber glue adhesion layer may be provided on the RFL adhesion layer 314.

The RFL adhesive layer 314 is formed of a solid content contained in the RFL aqueous solution, and includes a resorcin / formalin resin (RF resin) and a rubber component derived from rubber latex. The RFL adhesive layer 314 contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. The cellulosic fine fibers contained in the RFL adhesive layer 314 have the same configuration as that contained in the toothed belt body 310 in the seventh embodiment. As described above, the RFL adhesive layer 314 contains a cellulosic fine fiber having a fiber diameter distribution range of 50 to 500 nm, thereby obtaining a high adhesive force of the tooth side reinforcing fabric 312 to the toothed belt body 310. Can do.

In the RFL adhesive layer 314, the cellulosic fine fibers are not oriented in a specific direction and are not oriented.

The content of the cellulosic fine fibers in the RFL adhesive layer 314 is preferably 0.5% by mass or more, more preferably 1.% from the viewpoint of obtaining high adhesion of the tooth side reinforcing fabric 312 to the toothed belt body 310. It is 0 mass% or more, More preferably, it is 2.0 mass% or more, Preferably it is 12 mass% or less, More preferably, it is 10 mass% or less, More preferably, it is 8 mass% or less.

The content of the cellulosic fine fibers with respect to 100 parts by mass of the rubber component in the RFL adhesive layer 314 is preferably 1 part by mass or more from the viewpoint of obtaining high adhesion to the toothed belt body 310 of the tooth side reinforcing cloth 312. Preferably it is 3 mass parts or more, More preferably, it is 5 mass parts or more, Preferably it is 30 mass parts or less, More preferably, it is 20 mass parts or less, More preferably, it is 10 mass parts or less.

The RFL adhesive layer 314 preferably does not contain short fibers having a fiber diameter of 10 μm or more. However, the RFL adhesive layer 314 is short as long as the adhesiveness of the tooth portion side reinforcing cloth 312 to the toothed belt main body 310 is not hindered. Fibers may be included.

The rubber composition forming the base 311a of the toothed belt main body 310 may contain cellulosic fine fibers as in the seventh and second embodiments, or may not contain cellulosic fine fibers. ,either will do. The rubber composition forming the tooth portion 311b of the toothed belt main body 310 may contain cellulosic fine fibers as in the seventh and third embodiments, or may not contain cellulosic fine fibers. either will do.

Other configurations are the same as those in the seventh embodiment.

According to the toothed belt B according to the tenth embodiment having the above-described configuration, the RFL adhesive layer 314 provided between the tooth portion side reinforcing cloth 312 and the toothed belt main body 310 has a fiber diameter distribution range of 50 to 50. By containing the cellulosic fine fibers containing 500 nm, it is possible to obtain a high adhesive force of the tooth side reinforcing cloth 312 to the toothed belt main body 310, so that an excellent reinforcing effect is obtained. The chipping of the portion 311b is suppressed, and as a result, high durability can be obtained.

(Manufacturing method of toothed belt B)
In the method for manufacturing the toothed belt B according to the tenth embodiment, in the material preparation process, the tooth side reinforcing cloth 312 ′ is subjected to an adhesion treatment when the tooth side reinforcing cloth 312 ′ is manufactured. Specifically, an RFL adhesion treatment is performed on the tooth portion side reinforcing cloth 312 ′ by immersing it in an RFL aqueous solution and heating it. Moreover, it is preferable to perform the foundation | substrate adhesion | attachment process which immerses in a foundation | substrate adhesion | attachment processing liquid and heats before RFL adhesion | attachment processing. In addition, after RFL adhesion treatment, one type of soaking rubber glue adhesion treatment that is dipped in rubber glue and dried, and coating rubber glue adhesion treatment that coats and drys the rubber glue on the surface on the toothed belt body 310 side or Two types of rubber paste adhesion treatment may be performed.

《Base adhesion processing》
The base adhesion treatment liquid is, for example, a solution obtained by dissolving a base adhesion treatment agent such as epoxy resin or isocyanate resin (block isocyanate) in a solvent such as toluene, or a dispersion liquid dispersed in water. The temperature of the base adhesion treatment liquid is, for example, 20 to 30 ° C. The solid content concentration of the base adhesion treatment liquid is preferably 20% by mass or less.

The immersion time in the base adhesive treatment solution is, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after immersion in the base adhesion treatment liquid is, for example, 200 to 250 ° C. The heating time (residence time in the furnace) is, for example, 1 to 3 minutes. The number of times of base adhesion treatment may be only once or may be two or more. The base adhesive treating agent adheres to the tooth side reinforcing cloth 312 ′, and the amount of attachment (weight per unit area) is, for example, 0.5 to 8 based on the mass of the fiber material forming the tooth side reinforcing cloth 312 ′. % By mass.

<< RFL adhesion treatment >>
The RFL aqueous solution is an aqueous solution in which a dispersion (gel) in which cellulosic fine fibers are dispersed in water together with a rubber latex is mixed with an initial condensate of resorcin and formaldehyde. The liquid temperature of the RFL aqueous solution is, for example, 20 to 30 ° C.

The molar ratio of resorcin (R) to formalin (F) is, for example, R / F = 1/1 to 1/2. Examples of the rubber latex include vinylpyridine / styrene / butadiene rubber latex (Vp / St / SBR), chloroprene rubber latex (CR), chlorosulfonated polyethylene rubber latex (CSM), and the like. The solid content mass ratio of the initial condensate (RF) of resorcinol and formaldehyde and the rubber latex (L) is, for example, RF / L = 1/5 to 1/20.

The solid content concentration of the RFL aqueous solution is preferably 6.0% by mass or more, more preferably 9.0% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

The immersion time in the RFL aqueous solution is, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after immersion in the RFL aqueous solution is, for example, 100 to 180. The heating time (residence time in the furnace) is, for example, 1 to 5 minutes. The number of RFL adhesion treatments may be only once, or may be two or more. The RFL adhesive layer 314 is attached to the tooth side reinforcing cloth 312 ′, and the attached amount (weight per unit area) is, for example, 2 to 5% by mass based on the mass of the fiber material forming the tooth side reinforcing cloth 312 ′. It is.

Other methods are the same as those in the seventh embodiment.

[Embodiment 11]
Since the external configuration of the toothed belt B according to the eleventh embodiment is the same as that of the seventh embodiment, a description will be given below based on FIG.

In the toothed belt B according to the eleventh embodiment, the tooth-side reinforcing cloth 312 is immersed in an RFL aqueous solution and heated, and the soaking rubber paste bonding process is immersed in rubber paste and dried, and the toothed belt. One or two types of rubber glue adhesion treatment is applied among the coating rubber glue adhesion treatments in which the surface on the main body 310 side is coated with rubber glue and dried. Thus, as shown in FIG. 46, the tooth-side reinforcing cloth 312 has a toothed belt main body via the RFL adhesive layer 314 formed by the RFL adhesive treatment and the rubber glue adhesive layer 315 formed by the rubber glue adhesive treatment. Bonded to 310. In addition, before the RFL adhesion treatment, a foundation adhesion treatment comprising a solution obtained by dissolving a foundation adhesion treatment agent such as an epoxy resin or an isocyanate resin (block isocyanate) in a solvent such as toluene, or a dispersion liquid dispersed in water. It is preferable that a base adhesion treatment in which the substrate is immersed in a liquid and heated is performed, and a base adhesive layer is provided under the RFL adhesive layer 314.

The RFL adhesive layer 314 may contain cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm as in the seventh embodiment, or may not contain such cellulosic fine fibers. But you can.

The rubber paste adhesive layer 315 is formed of a solid rubber composition contained in the rubber paste, and the rubber composition forming the rubber paste adhesive layer 315 has a fiber diameter distribution range of 50 in the rubber component. An uncrosslinked rubber composition in which various rubber compounding agents are blended and kneaded in addition to cellulose fine fibers containing ˜500 nm is heated and pressurized and crosslinked with a crosslinking agent. As described above, since the rubber paste adhesive layer 315 contains the cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm, the adhesive strength of the tooth side reinforcing cloth 312 to the toothed belt body 310 is high. Can be obtained.

Examples of the rubber component of the rubber composition forming the rubber paste adhesive layer 315 include hydrogenated acrylonitrile rubber (H-NBR), hydrogenated acrylonitrile rubber reinforced with unsaturated carboxylic acid metal salt (H-NBR), ethylene, and the like. -Ethylene-α-olefin elastomers such as propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer, chloroprene rubber (CR), and chlorosulfonated polyethylene rubber (CSM) ) And the like. The rubber component of the rubber composition forming the toothed belt main body 310 is preferably a blend rubber of one or more of these. The rubber component of the rubber composition forming the rubber paste adhesive layer 315 may be the same as or different from the rubber component of the rubber composition forming the toothed belt main body 310.

The cellulosic fine fibers contained in the rubber composition forming the rubber paste adhesive layer 315 have the same configuration as that contained in the toothed belt body 310 in the seventh embodiment. In the rubber paste adhesive layer 315, the cellulosic fine fibers are not oriented in a specific direction and are not oriented.

The content of the cellulosic fine fibers in the rubber paste adhesive layer 315 is preferably 1 mass with respect to 100 parts by mass of the rubber component from the viewpoint of obtaining high adhesion of the tooth side reinforcing fabric 312 to the toothed belt body 310. Part or more, more preferably 3 parts by weight or more, still more preferably 5 parts by weight or more, and preferably 30 parts by weight or less, more preferably 20 parts by weight or less, still more preferably 10 parts by weight or less.

Examples of rubber compounding agents include reinforcing materials, friction coefficient reducing materials, cross-linking agents, and anti-aging agents.

As the reinforcing material, carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like. Silica is also mentioned as the reinforcing material. It is preferable that a reinforcing material is 1 type, or 2 or more types among these. The content of the reinforcing material is preferably smaller than the content of the reinforcing material in the rubber composition forming the toothed belt body 310, and is, for example, 10 to 30 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. is there.

Examples of the friction coefficient reducing material include ultra high molecular weight polyethylene resin powder, fluororesin powder, and molybdenum. The friction coefficient reducing material is preferably one or more of these. The content of the friction coefficient reducing material is, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be blended, an organic peroxide may be blended, or both of them may be used in combination. The compounding amount of the crosslinking agent is, for example, 0.3 to 5 parts by mass in the case of sulfur with respect to 100 parts by mass of the rubber component of the rubber composition, and 100 parts by mass of the rubber component of the rubber composition in the case of the organic peroxide. For example, it is 0.3 to 5 parts by mass.

Examples of the vulcanization accelerator include thiuram (eg, TETD, TT, TRA, etc.), thiazole (eg, MBT, MBTS, etc.), sulfenamide (eg, CZ), dithiocarbamate (eg, BZ-P). Etc.). It is preferable that a vulcanization accelerator is 1 type, or 2 or more types among these. The content of the vulcanization accelerator is, for example, 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the anti-aging agent include amine-ketone anti-aging agents, diamine anti-aging agents, phenol anti-aging agents and the like. It is preferable that an anti-aging agent is 1 type, or 2 or more types among these. The content of the anti-aging agent is, for example, 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition forming the rubber paste adhesive layer 315 preferably does not contain short fibers having a fiber diameter of 10 μm or more. However, the adhesiveness of the tooth side reinforcing cloth 312 to the toothed belt body 310 is not preferred. Such short fibers may be included as long as they do not hinder.

The rubber composition forming the base 311a of the toothed belt main body 310 may contain cellulosic fine fibers as in the seventh and second embodiments, or may not contain cellulosic fine fibers. ,either will do. The rubber composition forming the tooth portion 311b of the toothed belt main body 310 may contain cellulosic fine fibers as in the seventh and third embodiments, or may not contain cellulosic fine fibers. either will do.

According to the toothed belt B according to the eleventh embodiment, the rubber glue adhesive layer 315 provided between the tooth side reinforcing cloth 312 and the toothed belt main body 310 has a fiber diameter distribution range of 50. By containing cellulosic fine fibers containing ˜500 nm, it is possible to obtain a high adhesive force to the toothed belt body 310 of the tooth portion side reinforcing cloth 312, so that an excellent reinforcing effect is obtained. The chipping of the tooth portion 311b is suppressed, and excellent oil resistance can be obtained. Furthermore, since the rubber paste adhesive layer 315 contains cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm, it is possible to obtain high wear resistance on the tooth side surface. As a result, high durability can be obtained.

(Manufacturing method of toothed belt B)
In the manufacturing method of the toothed belt B according to the eleventh embodiment, in the material preparation step, the tooth part side reinforcing cloth 312 ′ is subjected to an adhesion process when the tooth part side reinforcing cloth 312 ′ is manufactured. Specifically, in addition to the RFL adhesion treatment in which the tooth portion side reinforcing cloth 312 ′ is immersed and heated in the RFL aqueous solution, the soaking rubber glue adhesion treatment in which the tooth side reinforcement cloth 312 ′ is immersed in the rubber glue and dried, and the toothed belt body One or two types of rubber glue adhesion treatment is performed among the coating rubber glue adhesion treatments in which the surface on the 310 side is coated with rubber glue and dried. In addition, it is preferable to perform the foundation | substrate adhesion | attachment process which is immersed in a foundation | substrate adhesion | attachment processing liquid and heated before RFL adhesion | attachment processing.

The base adhesion process is the same as that of the tenth embodiment.

<< RFL adhesion treatment >>
The RFL aqueous solution is an aqueous solution in which a rubber latex is mixed with an initial condensate of resorcin and formaldehyde. In the case where the cellulosic fine fibers are included in the RFL adhesive layer 314, a dispersion (gel) in which the cellulosic fine fibers are dispersed in water in the RFL aqueous solution may be included as in the tenth embodiment. The liquid temperature of the RFL aqueous solution is, for example, 20 to 30 ° C. The solid content concentration of the RFL aqueous solution is preferably 30% by mass or less.

The molar ratio of resorcin (R) to formalin (F) is, for example, R / F = 1/1 to 1/2. Examples of the rubber latex include vinylpyridine / styrene / butadiene rubber latex (Vp / St / SBR), chloroprene rubber latex (CR), chlorosulfonated polyethylene rubber latex (CSM), and the like. The solid content mass ratio of the initial condensate (RF) of resorcinol and formaldehyde and the rubber latex (L) is, for example, RF / L = 1/5 to 1/20.

The immersion time in the RFL aqueous solution is, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after immersion in the RFL aqueous solution is, for example, 100 to 180 ° C. The heating time (residence time in the furnace) is, for example, 1 to 5 minutes. The number of RFL adhesion treatments may be only once, or may be two or more. The RFL adhesive layer 314 is attached to the tooth side reinforcing cloth 312 ′, and the attached amount (weight per unit area) is, for example, 2 to 5% by mass based on the mass of the fiber material forming the tooth side reinforcing cloth 312 ′. It is.

<Rubber glue adhesion treatment>
The rubber paste is a solution in which an uncrosslinked rubber composition before crosslinking of a rubber composition containing cellulosic fine fibers forming the rubber paste adhesive layer 315 is dissolved in a solvent such as toluene. The rubber paste is produced as follows.

First, cellulosic fine fibers are put into a kneaded rubber component and dispersed by kneading.

Here, as a method for dispersing the cellulose-based fine fibers in the rubber component, for example, a dispersion (gel) in which the cellulose-based fine fibers are dispersed in water is added to the rubber component kneaded with an open roll, A method of vaporizing moisture while kneading them, a master of cellulose fine fibers / rubber obtained by mixing a dispersion (gel) in which cellulosic fine fibers are dispersed in water and rubber latex to vaporize the moisture A method in which a batch is put into a kneaded rubber component, a dispersion in which hydrophobic cellulose fine fibers are dispersed in a solvent, and a solution in which the rubber component is dissolved in a solvent are mixed and the solvent is evaporated. Of the obtained cellulose-based fine fiber / rubber masterbatch into the kneaded rubber component, and a dispersion (gel) in which the cellulose-based fine fiber is dispersed in water is freeze-dried A material obtained by pulverizing Te, how to put into a rubber component is masticated, methods and the like to introduce cellulosic microfibers made hydrophobic in rubber component is masticated.

Next, while kneading the rubber component and the cellulosic fine fiber, various rubber compounding agents are added and kneading is continued to prepare an uncrosslinked rubber composition.

Then, the uncrosslinked rubber composition is put into a solvent and stirred until a uniform solution is obtained, thereby producing a rubber paste. The temperature of the rubber paste is, for example, 20 to 30 ° C.

The solid content concentration of the rubber paste is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, for soaking rubber paste adhesion treatment. is there. For coating rubber paste adhesion treatment, it is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less.

In the case of soaking rubber glue bonding treatment, the immersion time in the rubber glue is, for example, 1 to 3 seconds. The drying temperature (furnace temperature) after immersion in rubber paste is, for example, 50 to 100 ° C. The drying time (residence time in the furnace) is, for example, 1 to 3 minutes. The number of times of the soaking rubber paste adhesion treatment may be only once, or may be two or more times. A rubber glue adhesive layer 315 is attached to the tooth side reinforcing cloth 312 ′. The amount of attachment (weight per unit area) is, for example, 2 to 5 mass based on the mass of the fiber material forming the tooth side reinforcing cloth 312 ′. %.

In the case of coating rubber paste adhesion treatment, the drying temperature (furnace temperature) after coating is, for example, 50 to 100 ° C. The drying time (residence time in the furnace) is, for example, 1 to 3 minutes. The number of times of coating rubber paste adhesion treatment may be only once or may be two or more times. A rubber glue adhesive layer 315 is attached to the tooth side reinforcing cloth 312 ′. The amount of attachment (weight per unit area) is, for example, 2 to 5 mass based on the mass of the fiber material forming the tooth side reinforcing cloth 312 ′. %.

Other methods are the same as those in the seventh embodiment.

(Uncrosslinked rubber composition)
The following rubbers 1 to 7 of an uncrosslinked rubber composition for forming a toothed belt body and rubbers 8 to 14 of an uncrosslinked rubber composition for a rubber paste adhesive layer of a tooth side reinforcing fabric were prepared. Each formulation is also shown in Tables 7 and 2.

<Rubber 1>
First, a dispersion in which powdered cellulose (trade name: KC Flock W-GK manufactured by Nippon Paper Industries Co., Ltd.) is dispersed in toluene is prepared, and the dispersion is collided with a high-pressure homogenizer to convert the powdered cellulose into cellulose fine fibers. The fiber was defibrated to obtain a dispersion in which cellulose fine fibers were dispersed in toluene. Accordingly, the cellulose fine fibers are produced by mechanical defibrating means and are not subjected to a hydrophobic treatment.

Next, the dispersion in which fine cellulose fibers are dispersed in toluene, and H-NBR (trade name: Zetpol 2020 manufactured by Nippon Zeon Co., Ltd.) are dissolved in toluene and a plasticizer (trade name: W-260 manufactured by DIC) is added. The resultant solution was mixed, and toluene and a plasticizer were vaporized to prepare a master batch of cellulose fine fiber / H-NBR. The content of each component in the master batch was 25% by mass for the cellulosic fine fibers, 25% by mass for the plasticizer, and 50% by mass for H-NBR.

Subsequently, H-NBR was masticated and a master batch was added thereto for kneading. The mixing mass ratio of H-NBR and masterbatch was 98: 4, and the content of fine cellulose fibers was 1 part by mass when the total H-NBR was 100 parts by mass.

Then, H-NBR, cellulose fine fiber, and plasticizer are kneaded, and 40 parts by mass of reinforcing material FEF carbon black (trade name: Seast SO manufactured by Tokai Carbon Co., Ltd.) is added to 100 parts by mass of H-NBR. 1 part by weight of processing aid stearic acid (trade name: Tsubaki stearic acid manufactured by NOF Corporation) and 5 parts by weight of zinc oxide (trade name: Zinc Oxide made by Sakai Chemical Industry Co., Ltd.) , 24 parts by mass of plasticizer, 5 parts by mass of liquid NBR (trade name: Nipol 1312 manufactured by Nippon Zeon Co., Ltd.) as a co-crosslinking agent, and 0% of sulfur (trade name: Oil Sulfur manufactured by Nippon Kibuki Kogyo Co., Ltd.) as a crosslinking agent. 5 parts by mass, 2 parts by mass of a thiuram vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd., trade name: Noxeller TET-G), and an amine-ketone antioxidant (manufactured by Ouchi Shinsei Co., Ltd., trade name: Nocrack 224) To prepare uncrosslinked rubber composition by parts by weight respectively turned to continue the kneading. The uncrosslinked rubber composition was designated as rubber 1. The content of the plasticizer in the rubber 1 is 25 parts by mass with respect to 100 parts by mass of H-NBR, including those contained in the master batch and those added later.

<Rubber 2>
Rubber 2 was an uncrosslinked rubber composition prepared in the same manner as rubber 1 except that the content of fine cellulose fibers was 3 parts by mass with respect to 100 parts by mass of H-NBR.

<Rubber 3>
Rubber 3 was an uncrosslinked rubber composition produced in the same manner as rubber 1 except that the content of cellulose fine fibers was 5 parts by mass with respect to 100 parts by mass of H-NBR.

<Rubber 4>
Rubber 4 was an uncrosslinked rubber composition prepared in the same manner as rubber 1 except that the content of cellulose fine fibers was 10 parts by mass with respect to 100 parts by mass of H-NBR.

<Rubber 5>
Rubber 5 was an uncrosslinked rubber composition produced in the same manner as rubber 1 except that the content of fine cellulose fibers was 15 parts by mass with respect to 100 parts by mass of H-NBR.

<Rubber 6>
Rubber 6 was an uncrosslinked rubber composition produced in the same manner as rubber 1 except that the content of cellulose fine fibers was 25 parts by mass with respect to 100 parts by mass of H-NBR.

<Rubber 7>
While masticating H-NBR, 40 parts by mass of FEF carbon black as a reinforcing material, 1 part by mass of stearic acid as a processing aid, and zinc oxide as a vulcanization accelerating agent are added to 100 parts by mass of H-NBR. 5 parts by weight, plasticizer 10 parts by weight, co-crosslinking agent liquid NBR 5 parts by weight, crosslinking agent sulfur 0.5 parts by weight, thiuram vulcanization accelerator 2 parts by weight, and amine-ketone system An uncrosslinked rubber composition was prepared by charging and kneading 2 parts by weight of each anti-aging agent. The uncrosslinked rubber composition was designated as rubber 7. Therefore, the rubber 7 does not contain cellulose fine fibers.

<Rubber 8>
Zinc methacrylate reinforced H-NBR (trade name: Zeoforte ZSC 2295, manufactured by Nippon Zeon Co., Ltd.) and H-NBR (trade name: Zetpole 2020, manufactured by Nippon Zeon Co., Ltd.) were kneaded with a mixing mass ratio of the former and the latter of 50:50. At the same time, 20 parts by mass of reinforcing material FEF carbon black (trade name: Seast SO manufactured by Tokai Carbon Co., Ltd.) and 100% by mass of these rubber components, ultrahigh molecular weight polyethylene powder (Mitsui) 10 parts by mass of trade name: Mipperon XM-220 manufactured by Kagaku Co., Ltd., 0.5 parts by mass of sulfur as a crosslinking agent (trade name: Oil Sulfur manufactured by Nippon Kibushi Kogyo Co., Ltd.), thiuram vulcanization accelerator (Ouchi Shinsei Chemical) 2 parts by mass of the product, product name: Noxeller TET-G), and 2 parts by mass of the amine-ketone anti-aging agent (trade name: Nocrack 224, manufactured by Ouchi Shinsei Co., Ltd.) And kneading to prepare an uncrosslinked rubber composition. The uncrosslinked rubber composition was designated as rubber 8. Accordingly, the rubber 8 does not contain cellulose fine fibers.

<Rubber 9>
Zinc methacrylate reinforced H-NBR and H-NBR were masticated, and a master batch was added thereto and kneaded. The content of cellulose fine fiber is 1 part by mass when the mixing mass ratio of zinc methacrylate reinforced H-NBR, H-NBR, and masterbatch is 50: 48: 4 and the total H-NBR is 100 parts by mass. It was made to become.

Then, zinc methacrylate reinforced H-NBR, H-NBR, fine cellulose fiber, and plasticizer are kneaded and reinforced with respect to 100 parts by mass of the zinc methacrylate reinforced H-NBR and H-NBR rubber components. 20 parts by mass of FEF carbon black as a material, 10 parts by mass of ultra high molecular weight polyethylene powder, 0.5 parts by mass of sulfur as a crosslinking agent, 2 parts by mass of a thiuram vulcanization accelerator, and an amine-ketone aging inhibitor 2 parts by mass of each was added and kneaded to prepare an uncrosslinked rubber composition. The uncrosslinked rubber composition was designated as rubber 9.

<Rubber 10>
The rubber 10 was an uncrosslinked rubber composition prepared in the same manner as the rubber 9 except that the cellulose fine fiber content was 3 parts by mass with respect to 100 parts by mass of the rubber component.

<Rubber 311>
The rubber 311 was an uncrosslinked rubber composition prepared in the same manner as the rubber 9 except that the cellulose fine fiber content was 5 parts by mass with respect to 100 parts by mass of the rubber component.

<Rubber 12>
Rubber 12 was an uncrosslinked rubber composition prepared in the same manner as rubber 9 except that the content of fine cellulose fibers was 10 parts by mass with respect to 100 parts by mass of the rubber component.

<Rubber 13>
Rubber 13 was an uncrosslinked rubber composition prepared in the same manner as rubber 9 except that the content of cellulose fine fibers was 15 parts by mass with respect to 100 parts by mass of the rubber component.

<Rubber 14>
The rubber 14 was an uncrosslinked rubber composition prepared in the same manner as the rubber 9 except that the content of the cellulose fine fiber was 25 parts by mass with respect to 100 parts by mass of the rubber component.

(Toothed belt for prototype evaluation)
The test evaluation toothed belts (tooth pitch 8 mm and belt width 10 mm) of Examples 7-1 to 7-13 and Comparative Example 7 below were produced. Each configuration is also shown in Table 9.

<Example 7-1>
For the toothed belt of Example 7-1, rubber 1 containing fine cellulose fibers was used as the uncrosslinked rubber composition forming the toothed belt body.

As the tooth side reinforcing fabric, a woven fabric was used in which a covering yarn obtained by winding an aramid fiber (trade name: Technora) on urethane yarn to give elasticity was used as a weft and a nylon twisted warp. The woven fabric of the tooth side reinforcing fabric was subjected to a base adhesion treatment that was heated after being immersed in an epoxy resin solution as a base adhesion treatment, and an RFL adhesion treatment that was heated after being immersed in an RFL aqueous solution. In addition, the soaking rubber paste bonding treatment in which the woven fabric of the tooth side reinforcing fabric subjected to the RFL bonding treatment was dipped in rubber paste and dried was repeatedly applied. As the rubber paste, a rubber paste having a solid content concentration of 10% by mass obtained by dissolving rubber 8 containing no cellulose fine fibers in toluene as a solvent was used. The liquid temperature of the rubber paste was 25 ° C. The immersion time in the rubber paste was 5 seconds. The drying temperature after immersion in rubber paste was 100 ° C. and the drying time was 40 seconds.

Glass fiber was used as the core wire.

<Example 7-2>
A toothed belt of Example 7-2 was prepared in the same manner as Example 7-1 except that rubber 2 containing cellulose fine fibers was used as the uncrosslinked rubber composition forming the toothed belt body.

<Example 7-3>
A toothed belt of Example 7-3 was prepared in the same manner as Example 7-1 except that rubber 3 containing fine cellulose fibers was used as the uncrosslinked rubber composition forming the toothed belt body.

<Example 7-4>
A toothed belt of Example 7-4 was prepared in the same manner as Example 7-1 except that rubber 4 containing cellulose fine fibers was used as the uncrosslinked rubber composition forming the toothed belt body.

<Example 7-5>
A toothed belt of Example 7-5 was produced in the same manner as Example 7-4 except that rubber paste of rubber 9 containing cellulose fine fibers was used for the soaking rubber paste bonding treatment of the tooth side reinforcing fabric. .

<Example 7-6>
A toothed belt of Example 7-6 was produced in the same manner as Example 7-4 except that rubber paste of rubber 10 containing cellulose fine fibers was used for the soaking rubber paste bonding treatment of the tooth side reinforcing fabric. .

<Example 7-7>
A toothed belt of Example 7-7 was prepared in the same manner as in Example 7-4 except that rubber paste of rubber 311 containing cellulose fine fiber was used for the soaking rubber paste adhesion treatment of the tooth side reinforcing fabric. .

<Example 7-8>
A toothed belt of Example 7-8 was prepared in the same manner as in Example 7-4 except that the rubber paste of rubber 12 containing fine cellulose fibers was used for the soaking rubber paste bonding treatment of the tooth side reinforcing fabric. .

<Example 7-9>
A toothed belt of Example 7-9 was produced in the same manner as Example 7-4 except that rubber paste of rubber 13 containing fine cellulose fibers was used for the soaking rubber paste bonding treatment of the tooth side reinforcing fabric. .

<Example 7-10>
A toothed belt of Example 7-10 was produced in the same manner as Example 7-4 except that rubber paste of rubber 14 containing cellulose fine fibers was used for the soaking rubber paste bonding treatment of the tooth side reinforcing fabric. .

<Example 7-11>
A toothed belt of Example 7-11 was produced in the same manner as Example 7-1 except that rubber 5 containing cellulose fine fibers was used as the uncrosslinked rubber composition forming the toothed belt body.

<Example 7-12>
A toothed belt of Example 7-12 was prepared in the same manner as Example 7-1 except that rubber 6 containing fine cellulose fibers was used as the uncrosslinked rubber composition forming the toothed belt body.

<Example 7-13>
As the uncrosslinked rubber composition forming the toothed belt body, rubber 7 containing no cellulose fine fibers is used, and the rubber paste of rubber 12 containing cellulose fine fibers is used for the soaking rubber paste bonding treatment of the tooth side reinforcing fabric. A toothed belt of Example 7-13 was produced in the same manner as Example 7-1 except that the above was found.

<Comparative Example 7>
As a non-crosslinked rubber composition for forming a toothed belt body, rubber 7 containing no cellulose fine fibers is used, and rubber glue of rubber 8 containing no cellulose fine fibers is used for the soaking rubber paste bonding treatment of the tooth side reinforcing fabric. A toothed belt of Comparative Example 7 was produced in the same manner as in Example 7-1 except that this was the case.

(Test evaluation method)
<Average fiber diameter and fiber diameter distribution of cellulose fine fiber>
Samples of rubber compositions in which rubbers 1 to 6 and rubbers 9 to 14 were crosslinked were taken from the toothed belt body and the rubber glue adhesive layer of the toothed belts of Examples 7-1 to 7-13. After freezing and pulverizing a sample of the rubber composition, the cross section thereof is observed with a scanning electron microscope (SEM), 50 fibers are arbitrarily selected, the fiber diameter is measured, the number average is obtained, and the average fiber is obtained. The diameter. Moreover, the maximum value and minimum value of the fiber diameter were calculated | required among 50 cellulose fine fibers.

<Belt running test>
FIG. 47 shows a pulley layout of the belt running test machine 330.

The belt running test machine 330 includes a driving pulley 331, a driven pulley 332, and an idler pulley 333. The drive pulley 331 is provided with 21 tooth-engagement grooves on the pulley periphery. The driven pulley 332 is provided with 42 tooth-engagement grooves on the periphery of the pulley. The idler pulley 333 has a flat pulley periphery for pressing the back surface of the belt. The drive pulley 331, the driven pulley 332, and the idler pulley 333 are all made of carbon steel (S45C).

Example 1 Each of the toothed belts B of Examples 7-1 to 7-13 and Comparative Example 7 was evaluated for chipping resistance and wear resistance using the belt running tester 330 as follows.

-Tooth chipping resistance evaluation-
The mass of the toothed belt B was measured in advance. Thereafter, the toothed belt B was wound around the belt running tester 330, a load was applied to the driven pulley 332 in the rearward direction, and a tension of 216N was applied to the toothed belt B. Then, the tension applied to the toothed belt B is set to 550 N, the driving pulley 331 is rotated at a rotational speed of 3000 rpm, the belt travels, and the travel time until the tooth part is lost is the tooth endurance life. It was. The belt running test was performed at room temperature for all of Examples 7-1 to 7-13 and Comparative Example 7, and Examples 7-1 to 7-4, Example 7-11, and Example 7 were performed. For -12 and Comparative Example 7, it was also performed in an 80 ° C. atmosphere.

-Wear resistance evaluation-
The toothed belt B was run for 300 hours under the same conditions as in the measurement of wear resistance. After running the belt, the mass of the toothed belt B was measured again, and the mass difference before and after running was calculated as the wear mass.

<Oil resistance test>
The toothed belts of Examples 7-1 to 7-13 and Comparative Example 7 were each measured for mass and then immersed in new engine oil at 140 ° C. for 168 hours. Thereafter, the adhered oil was sufficiently removed with an air gun, and the mass was measured again. The rate of change in mass before and after immersion (expressed in%) was calculated.

(Test evaluation results)
The test results are shown in Tables 10 and 5. Hereinafter, the content of the cellulose fine fiber means a part by mass with respect to 100 parts by mass of the rubber component even if not particularly described.

<Average fiber diameter and fiber diameter distribution of cellulose fine fiber>
According to Table 10, it can be seen that the cellulose fine fibers contained in the rubber composition obtained by crosslinking the rubbers 1 to 6 and the rubbers 9 to 14 all have a wide fiber diameter distribution.

<Belt running test>
-Tooth chip resistance (room temperature)-
In Comparative Example 7 in which neither the toothed belt main body nor the rubber paste adhesive layer contained cellulose fine fibers, the tooth part durable life at room temperature was 384 hours.

On the other hand, cellulose fine fibers are contained only in the toothed belt body, and the contents thereof are 0 parts by weight, 1 part by weight, 3 parts by weight, 5 parts by weight, 10 parts by weight, and 15 parts by weight, respectively. In Examples 7-1 to 7-4 and Examples 7-11 to 7-12 having 25 parts by mass, the tooth endurance life at room temperature was 528 hours, 696 hours, time 792, 864 hours, 936 hours and 1056 hours. That is, in the range of the present Example, it turns out that tooth | gear part durable life becomes long as content of a cellulose fine fiber increases.

In Examples 7-4 to 7-10, in which the content of cellulose fine fibers in the toothed belt body is the same 10 parts by mass, as the content of cellulose fine fibers in the rubber paste adhesive layer increases, It can be seen that the endurance life of the tooth is long. Specifically, the cellulose fine fiber content in the rubber paste adhesive layers in Examples 7-4 to 7-10 is 0 parts by weight, 1 part by weight, 3 parts by weight, 5 parts by weight, and 10 parts by weight, respectively. , 15 parts by weight, and 25 parts by weight, while the tooth endurance life at room temperature was 864 hours, 912 hours, 960 hours, 1032 hours, 1080 hours, 1128 hours, and 1128 hours, respectively. In Examples 7-9 and 7-10, since the tooth endurance life is the same, when the content of the fine cellulose fiber is 15 parts by mass or more, the effect of increasing the tooth endurance is saturated. Possible possibility.

Further, in Example 7-13 in which only 10 parts by mass of cellulose fine fiber was contained only in the rubber adhesive adhesive layer, the durable life of the tooth portion was 456 hours, which is slightly longer than that of 384 hours in Comparative Example 7. However, in Example 7-8 in which the content of cellulose fine fibers in the toothed belt body is 10 parts by mass, the content of cellulose fine fibers in the rubber paste adhesive layer is the same as in Example 7-13. It can be seen that the tooth endurance life is significantly excellent at 1080 hours.

From the above, although the durable life of the tooth portion is improved when cellulose fine fibers are contained in any of the toothed belt body and the rubber paste adhesive layer, the effect is more remarkable when it is contained in the toothed belt body. I understand that.

-Tooth chip resistance (80 ° C)-
In Comparative Example 7 in which neither the toothed belt body nor the rubber paste adhesive layer contained cellulose fine fibers, the tooth part durable life at 80 ° C. was 240 hours.

On the other hand, cellulose fine fibers are contained only in the toothed belt body, and the contents thereof are 0 parts by weight, 1 part by weight, 3 parts by weight, 5 parts by weight, 10 parts by weight, and 15 parts by weight, respectively. In Examples 7-1 to 7-4 and Examples 7-11 to 7-12 having 25 parts by mass, the tooth endurance life at 80 ° C. was 432 hours, 624 hours, 744 hours, and 792 hours, respectively. 888 hours, and 9126 hours. That is, in the range of the present Example, it turns out that the tooth | gear durable life at high temperature becomes long as content of a cellulose fine fiber increases.

Further, the tooth endurance life at high temperature (80 ° C.) is shorter than the tooth endurance life at room temperature. However, it turns out that the deterioration is reduced by containing the cellulose fine fiber. That is, in Comparative Example 7, the tooth endurance life at room temperature was 384 hours, whereas the tooth endurance life at 80 ° C. was 240 hours, which was deteriorated by about 38%. On the other hand, in Example 7-1 in which 1 part by mass of cellulose fine fiber was contained in the toothed belt body, the tooth endurance life at room temperature was 528 hours, whereas the tooth endurance life at 80 ° C. Is 432 hours, and the deterioration is about 18%. In Example 7-2, Example 7-3, Example 7-4, Example 7-11 and Example 7-12, the deterioration was 10%, 6%, 8%, 5% and 14 in this order. It can be seen that, in any case, it is greatly reduced as compared with the case where the fine cellulose fibers are not included.

As described above, a decrease in the coefficient of linear expansion can be considered as a factor for reducing deterioration of the durable life of the tooth portion at a high temperature due to the inclusion of the fine cellulose fibers. That is, the linear expansion coefficient of a toothed belt falls by containing a cellulose fine fiber. When the linear expansion coefficient decreases, the expansion of the tooth portion at a high temperature is suppressed. As a result, the meshing accuracy between the tooth part and the pulley is maintained even at a high temperature, and an increase in the burden on the tooth part due to the temperature rise is suppressed, and as a result, the deterioration of the durable life of the tooth part at a high temperature is not suppressed. I guess that.

-Abrasion resistance-
In Comparative Example 7 in which neither the toothed belt body nor the rubber paste adhesive layer contained cellulose fine fibers, the wear mass was 4.1 g. In Examples 7-1 to 7-4 and Examples 7-11 to 7-12 in which cellulose fine fibers are contained only in the toothed belt body, the wear mass is 3.9 g to 4. It was 3 g. Therefore, it can be seen that even if cellulose fine fibers are contained only in the toothed belt body, no particular improvement in wear resistance is observed.

In contrast, in Examples 7-4 to 7-10 in which the content of cellulose fine fibers in the toothed belt body is the same 10 parts by mass, the content of cellulose fine fibers in the rubber paste adhesive layer is 0 respectively. While the weight parts are 1 part by weight, 3 parts by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, and 25 parts by weight, the wear mass is 4.2 g, 3.3 g, 2.5 g, 2 0.1 g, 1.8 g, 1.4 g, and 1.3 g. That is, it is understood that the wear mass decreases as the content of the cellulose fine fiber in the rubber paste adhesive layer increases. Here, if the wear mass is 3.5 g or less, it is considered that the wear mass is improved significantly over the conventional technique.

Further, in Examples 7-13 in which the toothed belt body does not contain cellulose fine fibers, the rubber paste adhesive layer contains 10 parts by weight of cellulose fine fibers, and the wear mass is 2.0 g, which is remarkable. It can be seen that the wear resistance is improved.

From the above, it is considered that the effect of improving the wear resistance is exhibited by the inclusion of cellulose fine fibers in the rubber paste adhesive layer of the tooth side reinforcing fabric.

<Oil resistance test>
In Comparative Example 7 in which neither the toothed belt body nor the rubber paste adhesive layer contained cellulose fine fibers, the mass change amount before and after oil swelling as an evaluation index of oil resistance was 4.4%.

On the other hand, cellulose fine fibers are contained only in the toothed belt body, and the contents thereof are 0 parts by weight, 1 part by weight, 3 parts by weight, 5 parts by weight, 10 parts by weight, and 15 parts by weight, respectively. In Examples 7-1 to 7-4 and Examples 7-11 to 7-12 having 25 parts by mass, the mass change amounts were 3.9%, 3.7%, 3.1%, 2.8%, 1.9%, and 1.5%. That is, in the range of the present Example, it turns out that mass change amount becomes small as content of a cellulose fine fiber increases, and oil resistance improves.

In Examples 7-4 to 7-10, in which the content of cellulose fine fibers in the toothed belt body is the same 10 parts by mass, the content of cellulose fine fibers in the rubber paste adhesive layer is 0 parts by mass, respectively. 1 part by mass, 3 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, and 25 parts by mass, while the mass change amount is 2.8%, 2.8%, 2.7% in order. 2.6%, 2.3%, 2.2%, and 2.1%. That is, it can be seen that as the content of the cellulose fine fiber in the rubber paste adhesive layer increases, the mass change rate decreases, and the oil resistance improves.

Further, in Example 7-13 in which only 10 parts by mass of cellulose fine fiber was contained only in the adhesive layer of rubber paste, the mass change rate was 4.3%, which was slightly suppressed from 4.4% of Comparative Example 7. Has been. In the case of Example 7-8 in which the content of the cellulose fine fiber in the toothed belt body is 10 parts by mass, the content of the cellulose fine fiber in the rubber paste adhesive layer is the same as in Example 7-13, but the rate of mass change Is 2.3%.

From the above, it is possible to improve the oil resistance by containing cellulose fine fibers in the toothed belt body, and even when cellulose fine fibers are contained only in the rubber paste adhesive layer of the tooth side reinforcing fabric, the effect is Even if it is small, it can be seen that the oil resistance is improved. It can also be seen that when the fine cellulose fibers are contained in the rubber paste adhesive layer in addition to the toothed belt body, the oil resistance is significantly improved.

The present invention is useful in the field of rubber compositions and transmission belts using the rubber compositions.

DESCRIPTION OF SYMBOLS 10 Belt main body 11 Bottom rubber layer 12 Adhesive rubber layer 13 Stretch rubber layer 14 Core wire 15 Reinforcement cloth
110 V-ribbed belt main body 111 Compressed rubber layer 112 Adhesive rubber layer 113 Back rubber layer 116 Short fiber 120 Flat belt main body 121 Inner rubber layer 122 Adhesive rubber layer 123 Outer rubber layer 126 Short fiber
210 (V-ribbed) belt body 210a Inner rubber layer 211a Surface rubber layer
310 toothed belt body 311a base 311b tooth 312 core 313 tooth side reinforcing cloth 314 RFL adhesive layer 315 rubber glue adhesive layer

Claims (21)

In a rubber composition containing a rubber component and cellulosic fine fibers,
A rubber composition characterized in that a fiber diameter distribution range of the cellulosic fine fibers includes 50 to 500 nm. The rubber composition according to claim 1, wherein
A rubber composition comprising carbon black as a filler. The rubber composition according to claim 2,
The carbon black has at least one of a hydroxyl group, a carbonyl group, and a carboxyl group. The rubber composition according to any one of claims 1 to 3,
A rubber composition comprising silica as a filler. In the rubber composition according to any one of claims 1 to 4,
The rubber composition, wherein the rubber component is an ethylene-α-olefin elastomer. In the rubber composition according to any one of claims 1 to 5,
The cellulosic fine fiber is produced by a mechanical defibrating means. In the rubber composition according to any one of claims 1 to 5,
The rubber composition according to claim 1, wherein the cellulosic fine fibers are produced by chemical defibrating means. A transmission belt in which at least a part of the belt body is formed of a rubber composition containing cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. The transmission belt according to claim 8,
A power transmission belt having a content of 1 to 25 parts by mass of the cellulose-based fine fibers with respect to 100 parts by mass of a rubber component of the rubber composition. The power transmission belt according to claim 8 or 9,
The rubber composition is a power transmission belt containing short fibers having a fiber diameter of 10 μm or more. In the power transmission belt according to any one of claims 10,
A power transmission belt in which the content of the short fiber relative to 100 parts by mass of the rubber component of the rubber composition is larger than the content of the cellulosic fine fibers relative to 100 parts by mass of the rubber component of the rubber composition. The transmission belt according to claim 8,
The power transmission belt, wherein the rubber composition is a porous rubber composition. The power transmission belt according to claim 12,
A transmission belt comprising a fiber diameter distribution range of the cellulosic fine fibers of 20 nm to 1 μm. The power transmission belt according to claim 12 or 13,
A power transmission belt having a cellulose fine fiber content of 1 to 20 parts by mass with respect to 100 parts by mass of the rubber component in the porous rubber composition. The transmission belt according to any one of claims 12 to 14,
A transmission belt in which a pulley contact portion of the belt body is formed of the porous rubber composition. The transmission belt according to claim 8,
The transmission belt is
A toothed belt main body having a flat belt-like base portion and a plurality of tooth portions integrally provided at a distance in the belt length direction on one surface of the base portion;
A tooth-side reinforcing cloth pasted to cover the tooth-side surface of the toothed belt body through an adhesive layer containing a rubber component;
A toothed belt with
At least one of the base part, the tooth part and the adhesive layer is formed of the rubber composition containing cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm. . The transmission belt according to claim 16,
The power transmission belt, wherein the content of the cellulose fine fibers in the rubber composition is 1 to 30 parts by mass with respect to 100 parts by mass of the rubber component. The transmission belt according to claim 16 or 17,
A power transmission belt, wherein the rubber component of the rubber composition forming the toothed belt body includes hydrogenated acrylonitrile rubber. The transmission belt according to any one of claims 16 to 18,
A power transmission belt, wherein the rubber component contained in the adhesive layer includes hydrogenated acrylonitrile rubber and hydrogenated acrylonitrile rubber reinforced with an unsaturated carboxylic acid metal salt. The transmission belt according to any one of claims 8 to 19,
The power transmission belt, wherein the cellulosic fine fibers are produced by mechanical defibrating means. A method for producing a transmission belt in which at least a part of a belt body is formed of a porous rubber composition containing cellulosic fine fibers,
The cellulosic fine fiber has a fiber diameter distribution range of 50 to 500 nm,
A method for producing a transmission belt, wherein the porous rubber composition is formed using a foaming agent, a supercritical fluid, or a subcritical fluid.

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