JP2008157445A - Friction transmission belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction transmission belt and a method of manufacturing the friction transmission belt excelling in power transmission property and sound reducing property in both dry travel and wet travel and maintaining its effect over a long period of time. <P>SOLUTION: A V-ribbed belt 1 comprises an elastic body layer including a rubber layer with core wires 2 embedded along the longitudinal direction of the belt, wherein a rib part 6 used as a friction transmission surface is composed of a rubber composition containing 5-50 pts.mass of water soluble polymer with a melting point or softening point of 80°C or lower to 100 pts.wt. of ethylene-α-olefin elastomer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a friction transmission belt used for a drive device and the like, and a manufacturing method thereof.

  The characteristics required for the friction transmission belt used in the drive device include not only high power transmission but also no abnormal noise during use, and excellent durability and particularly wear resistance. In order to satisfy these characteristics, the friction transmission part is composed of a rubber composition blended with short fibers such as polyamide, meta-aramid or para-aramid, and the friction transmission surface is covered with them to produce sound resistance and wear resistance. In general, improvement of adhesive wear resistance is achieved.

  Considering the usage environment of the automobile, the transmission belt is not used only in a dry state, but is often used in a wet state. For example, it may run in a wet state where rainwater or muddy water has entered the engine room, but at this time, a water film will be generated on the belt surface and pulley surface, causing the belt to slip and sound, or to reduce transmission Troubles such as doing are regarded as problems. That is, in recent years, there is a demand for excellent silence and power transmission not only in a dry state but also in a wet state.

  On the other hand, in recent years, with the social demand for energy saving and downsizing, parts in the engine room of automobiles tend to be densely arranged. Is rising. In such a high temperature atmosphere, a problem has been pointed out that the rubber constituting the transmission belt is hardened and cracks occur at an early stage. In addition, as the energy is saved, the rotational fluctuation of the engine increases, and the influence of the fluctuation increases the tension fluctuation of the transmission belt, causing problems such as early wear and sound generation. Furthermore, since a rubber containing halogen such as chloroprene leads to generation of dioxins, a belt made of a rubber not containing halogen, which is an environmental load substance, has recently been demanded.

  In response to this requirement, ethylene / α-olefin rubber such as ethylene / propylene copolymer rubber (EPM) or ethylene / propylene / diene copolymer rubber (EPDM) has excellent heat resistance and comparison. It is also promising because it is an inexpensive polymer and meets the requirement of dehalogenation. However, ethylene / α-olefin elastomers have poor wettability with water compared to chloroprene rubber, etc., and are likely to repel water. There was a problem that the difference with the performance of the state was large.

  In order to deal with these problems, rubber with friction transmission part combined with short fibers such as polyamide, meta-aramid or para-aramid, and organic short fibers with excellent hydrophilicity, specifically cotton short fibers. Attempts have been made to compose the composition. For example, the rib portion of the V-ribbed belt contains cotton short fibers and intermediate short fibers having an elastic modulus intermediate between the elastic modulus of the main rubber constituting the rib portions and the elastic modulus of the cotton short fibers, thereby allowing rotation. There is known a V-ribbed belt capable of reducing noise during water injection even when it is mounted on an auxiliary drive system of an engine having a large fluctuation or load. (For example, see Patent Document 1)

Further, as a measure against sound generation during water injection, in a transmission belt in which a compression rubber layer is disposed on the bottom surface side of the core, a short fiber made of gelable polyvinyl alcohol fiber subjected to RFL treatment is formed on the compression rubber layer. Also known is a transmission belt characterized in that it is disposed so as to be exposed on the surface of the layer, and which suppresses a reduction in the transmission capability of the belt due to slippage during water injection and the generation of abnormal noise. (For example, refer to Patent Document 2).
JP 2003-202055 A JP 2006-118661 A

  However, when coping with cotton short fibers as in Patent Document 1, cotton short fibers have a problem of poor dispersion in rubber and adversely affecting processability. Specifically, in the rolling process of the rubber sheet, the surface of the sheet is raised and a smooth rubber sheet cannot be obtained, or in the lamination of the rubber sheet, the adhesion between the sheets is poor and the preforming is poor. There was a bug. Also, as in Patent Document 2, when polyvinyl alcohol short fibers are blended, although an effect is seen during wet running, there is little improvement in slidability during dry running, and as a result, a transmission belt with a high sound suppression effect I could not say it. Furthermore, although the transmission belts of Patent Documents 1 and 2 have various effects due to the presence of specific short fibers, there is a problem in that the short fibers are dropped and worn by running, and the effect does not last with time. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power transmission belt that is excellent in power transmission and quietness both during dry travel and during wet travel and that can sustain its effects over a long period of time. It is to be.

  The present invention is a friction transmission belt, wherein at least a part of the friction transmission surface contains 5 to 50 parts by mass of a water-soluble polymer having a melting point or a softening point of 80 ° C. or less with respect to 100 parts by mass of rubber. A friction transmission belt comprising a composition.

  According to the present invention, in the friction transmission belt, the rubber is mainly composed of an ethylene / α-olefin elastomer; the water-soluble polymer has a melting point or softening point of 50 to 80 ° C .; the water-soluble polymer is polyethylene. The invention is characterized in that the friction transmission belt is a V-ribbed belt.

  The present invention is also a method for producing a friction transmission belt, wherein at least a part of the friction transmission surface is 5 to 50 masses of water-soluble polymer having a melting point or softening point of 80 ° C. or less with respect to 100 parts by mass of rubber. A method for producing a friction transmission belt, comprising forming a partially blended rubber composition by vulcanization molding.

  In the friction transmission belt according to the present invention, the rubber composition is obtained by kneading rubber and a water-soluble polymer at the melting point or the softening point or higher; the rubber is mainly composed of an ethylene / α-olefin elastomer. The melting point or softening point of the water-soluble polymer is 50 to 80 ° C .; the water-soluble polymer is polyethylene oxide; and the friction transmission belt is a V-ribbed belt.

  The friction transmission belt according to claim 1 is capable of ensuring an appropriate coefficient of friction by running the melted / softened water-soluble polymer as a lubricant when running in a dry state, Heat resistance durability can be improved. On the other hand, when driving in a wet state, the water-soluble polymer on the friction transmission surface absorbs / dissolves, thereby improving the wettability of the friction transmission surface. To improve the quietness and the transmission. This also has the effect of reducing the difference in transmission performance between the dry state and the wet state. Furthermore, these effects can be sustained over a long period of time.

  The friction transmission belt according to claim 2 of the present application can enhance the effect of bleeding the water-soluble polymer to the friction transmission surface by utilizing the difference in polarity between the ethylene / α-olefin elastomer and the water-soluble polymer.

  The friction transmission belt according to claim 3 of the present application has an effect that the water-soluble polymer at room temperature does not bleed, so that the water-soluble polymer can be prevented from escaping during storage or standing.

  In the friction transmission belt according to claim 4 of the present application, by selecting a specific water-soluble polymer (polyethylene oxide), the bleed during running can be made appropriate while suppressing the bleed during standing. .

  The friction transmission belt according to claim 5 has a small difference in transmission performance and soundproof performance between a dry state and a wet state, and can reduce sound generation due to stick-slip or the like when wet, over a long period of time. It is possible to extend the life of the belt by suppressing the above.

  In the method of manufacturing a friction transmission belt according to claim 6, at least a part of the friction transmission surface is formed of 5 to 50 water-soluble polymers having a melting point or a softening point of 80 ° C. or less with respect to 100 parts by mass of rubber. It is possible to produce a friction transmission belt composed of a rubber composition containing part by mass. When running in a dry state, this friction transmission belt can ensure a suitable coefficient of friction by the melted / softened water-soluble polymer acting as a lubricant, and also improves sound resistance and durability during running. Can be made. On the other hand, when driving in a wet state, the water-soluble polymer on the friction transmission surface absorbs / dissolves, thereby improving the wettability of the friction transmission surface. To improve the quietness and the transmission. This also has the effect of reducing the difference in transmission performance between the dry state and the wet state. Moreover, these effects can be sustained over a long period of time.

  The method for producing a friction transmission belt according to claim 7 of the present invention is such that the water-soluble polymer is melted or softened by kneading the rubber and the water-soluble polymer at a melting point or a softening point or higher before vulcanization molding and kneaded into the rubber. It is possible to form a rubber composition in which a water-soluble polymer is well dispersed by a polymer alloy. Thereby, a uniform surface state can be ensured and various stable effects can be achieved. The rubber composition thus obtained can have a sea-island structure in which the rubber is a continuous layer and the water-soluble polymer is a dispersed layer.

  The manufacturing method of the friction transmission belt according to claim 8 of the present invention uses a difference in polarity between the ethylene / α-olefin elastomer and the water-soluble polymer to improve the effect of bleeding the water-soluble polymer to the friction transmission surface. A transmission belt can be manufactured.

  The manufacturing method of the friction transmission belt according to claim 9 of the present application manufactures a friction transmission belt in which the water-soluble polymer does not bleed at room temperature, so that the dissipation of the water-soluble polymer during storage or standing is suppressed. There is an effect that can be.

  The friction transmission belt according to claim 10 of the present application is a friction transmission belt in which a specific water-soluble polymer (polyethylene oxide) is selected to suppress bleeding at the time of standing and make the bleeding at the time of running appropriate. Can be manufactured.

  The friction transmission belt according to claim 11 has a small difference in transmission performance and soundproof performance between a dry state and a wet state, can reduce sound generation due to stick-slip or the like when wet, and can prevent cracks in the ribs. Thus, it is possible to manufacture a friction transmission belt having a long life by suppressing the above.

  Embodiments of the present invention will be described. In the present embodiment, the present invention is applied to a V-ribbed belt having a plurality of rib portions extending in the longitudinal direction of the belt as a friction transmission belt.

  As shown in FIG. 1, the V-ribbed belt 1 includes an adhesive layer 3 in which a core wire 2 is embedded in the longitudinal direction of the belt, a compression layer 4 provided on one surface of the adhesive layer 3, and the other of the adhesive layer 3. And a stretch layer 5 made of a cover canvas covering the surface of the cover. The compressed layer 4 is provided with a plurality of rib portions 6 having a substantially triangular cross section extending in the belt longitudinal direction. Here, the friction transmission surface refers to the surface layer of the compression layer 6.

  The core wire 2 used in the present invention includes polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, polytrimethylene terephthalate (PTT) fiber, polybutylene terephthalate (PBT) fiber, polyparaphenylene benzobisoxazole (PBO). ) Twisted cords composed of fibers, polyamide fibers, glass fibers, aramid fibers, or the like can be used.

  The core wire is preferably subjected to an adhesive treatment. For example, (1) After impregnating the untreated cord into a tank containing a treatment liquid selected from an epoxy compound and an isocyanate compound, and pre-dip (2) 160 Dry in a drying oven set at a temperature of ~ 200 ° C for 30-600 seconds, (3) then immerse in a tank containing an adhesive solution consisting of a resorcin-formaldehyde-latex solution (RFL solution), (4) It can be stretched by −1 to 3% for 30 to 600 seconds through a stretching heat setting processor set at a temperature of 210 to 260 ° C. to obtain a stretching treatment cord.

  Examples of the isocyanate compound used in this pretreatment liquid include 4,4′-diphenylmethane diisocyanate, tolylene 2,4-diisocyanate, polymethylene polyphenyl diisocyanate, hexamethylene diisocyanate, and polyaryl polyisocyanate (for example, PAPI as a trade name) ) Etc. This isocyanate compound is used by mixing with an organic solvent such as toluene or methyl ethyl ketone.

  In addition, blocked polyisocyanates in which the isocyanate group of the polyisocyanate is blocked by reacting the isocyanate compound with a blocking agent such as phenols, tertiary alcohols, and secondary alcohols can also be used.

  Examples of the epoxy compound include reaction products of polyhydric alcohols such as ethylene glycol, glycerin and pentaerythritol, polyalkylene glycols such as polyethylene glycol and halogen-containing epoxy compounds such as epichlorohydrin, resorcin, bis (4-hydroxy Phenyl) dimethylmethane, phenol-formaldehyde resin, resorcinol-formaldehyde resin and other polyhydric phenols and reaction products with halogen-containing epoxy compounds. The epoxy compound is used by mixing with an organic solvent such as toluene or methyl ethyl ketone.

  The RFL treatment liquid is a mixture of resorcin and formaldehyde precondensate with rubber latex. In this case, the molar ratio of resorcin and formaldehyde is preferably 1: 2 to 2: 1 in order to increase the adhesive force. . If the molar ratio is less than 1/2, the three-dimensional reaction of resorcin-formaldehyde resin progresses too much and gels. On the other hand, if it exceeds 2/1, the reaction between resorcin and formaldehyde does not progress so much. To do.

  Examples of rubber latex include styrene / butadiene / vinylpyridine terpolymers, hydrogenated nitrile rubber, chloroprene rubber, and nitrile rubber.

  Further, the solid content mass ratio of the initial condensate of resorcin / formaldehyde and the rubber latex is preferably 1: 2 to 1: 8, and if this range is maintained, it is suitable for increasing the adhesive force. When the above ratio is less than 1/2, the resin content of resorcin-formaldehyde increases, the RFL film becomes hard and the dynamic adhesion becomes worse, and when it exceeds 1/8, the resin content of resorcin-formaldehyde. Therefore, the RFL film becomes soft and the adhesive strength decreases.

  Further, a vulcanization accelerator or a vulcanizing agent may be added to the RFL liquid, and the vulcanization accelerator to be added is a sulfur-containing vulcanization accelerator. Specifically, 2-mercaptobenzothiazole (M ) And salts thereof (for example, zinc salts, sodium salts, cyclohexylamine salts, etc.) thiazoles such as dibenzothiazyl disulfide (DM), sulfenamides such as N-cyclohexyl-2-benzothiazylsulfenamide (CZ) , Thiurams such as tetramethylthiuram monosulfide (TS), tetramethylthiuram disulfide (TT), dipentamethylenethiuram tetrasulfide (TRA), sodium di-n-butyldithiocarbamate (TP), zinc dimethyldithiocarbamate ( PZ) Dithiocarbamine such as zinc diethyldimethyldithiocarbamate (EZ) There are salts and the like.

  Examples of the vulcanizing agent include sulfur, metal oxides (zinc oxide, magnesium oxide, lead oxide), organic peroxides, and the like, which are used in combination with the above vulcanization accelerator.

  The canvas constituting the stretch layer 5 is a fiber base selected from woven fabric, knitted fabric, non-woven fabric, and the like. Known and publicly used fiber materials can be used. For example, natural fibers such as cotton, hemp and bamboo, inorganic fibers such as metal fibers and glass fibers, and polyamides, polyesters, polyethylenes, polyurethanes, polystyrenes, Examples thereof include organic fibers such as fluoroethylene, polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid. In the case of a woven fabric, these yarns are woven by plain weaving, twill weaving, satin weaving or the like.

  The canvas is preferably immersed in the RFL liquid according to a known technique. In addition, after immersion in the RFL solution, friction can be performed by rubbing unvulcanized rubber into the canvas, or immersion can be performed in a soaking solution in which the rubber is dissolved in a solvent. The RFL solution may be appropriately mixed with a carbon black solution to blacken the treatment, or a known surfactant may be added in an amount of 0.1 to 5.0% by mass.

  Here, the compression layer 4 is composed of a rubber composition containing 5 to 50 parts by weight of a water-soluble polymer having a melting point or a softening point of 80 ° C. or less with respect to 100 parts by weight of rubber.

  Examples of rubber include natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, ethylene / α-olefin elastomer, chlorosulfonated polyethylene, alkylated chlorosulfonated polyethylene, epichlorohydrin rubber, urethane rubber, hydrogenated nitrile rubber, hydrogen A mixed polymer of a nitrile rubber and an unsaturated carboxylic acid metal salt or the like may be used alone or in combination. Among these, ethylene / α-olefin elastomers have excellent ozone resistance, heat resistance, and cold resistance, and are relatively inexpensive polymers that meet the requirements for dehalogenation. It is preferable that That is, as the rubber component, an ethylene / α-olefin elastomer alone or a blend rubber obtained by mixing a rubber made of other types of rubber and an ethylene / α-olefin elastomer is desirable. Further, when blending, the ethylene / α-olefin elastomer is a main component (refers to the rubber of the component most contained in the rubber composition, for example, if it contains 50% by weight or more) Component). When goethylene / α-olefin elastomer is the main component, it is possible to make the water-soluble polymer easier to bleed on the friction transmission surface by utilizing the difference in polarity between the ethylene / α-olefin elastomer and the water-soluble polymer. .

  Examples of the ethylene / α-olefin elastomer include a copolymer of ethylene and α-olefin (propylene, butene, hexene, or octene), or a copolymer of ethylene, the α-olefin, and a nonconjugated diene. Specifically, it refers to rubber such as EPM and EPDM. Examples of the diene component include non-conjugated dienes having 5 to 15 carbon atoms such as ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, and methylene norbornene.

  Specific examples of the water-soluble polymer having a melting point or softening point of 80 ° C. or lower include polyethylene oxide. When a water-soluble polymer having a melting point or softening point exceeding 80 ° C. is contained, the water-soluble polymer does not melt / soften even during heat generation during running and may not sufficiently bleed on the friction transmission surface. Therefore, the soundproofing performance in a dry state and a wet state is insufficient. However, when a water-soluble polymer having a melting point or softening point of 80 ° C. or less is contained as in the present invention, the melted / softened water-soluble polymer bleeds and acts as a lubricant when running in a dry state. To do. On the other hand, in running in a wet state, the water-soluble polymer on the friction transmission surface absorbs / dissolves, so that the wettability of the friction transmission surface is improved. As a result, the heat resistance and durability of the transmission belt are improved, and the sound-proofing performance in a dry state and a wet state is excellent, and the difference is reduced. More preferably, the melting point or softening point is 50 to 80 ° C. Within this range, the water-soluble polymer does not bleed when stored at room temperature or at rest, and the water-soluble polymer is dissipated. In addition to being able to suppress this, there are advantages that the surface is not sticky and handling is good. Specifically, polyethylene oxide is preferably used.

  The content of the water-soluble polymer having a melting point or softening point of 80 ° C. or less is 5 to 50 parts by mass with respect to 100 parts by mass of the rubber. If the amount is less than 5 parts by mass, there is almost no effect due to the inclusion.

  The shape at the time of blending the water-soluble polymer is not limited to a granular shape or a fiber shape, and the shape of the water-soluble polymer in the belt molded body after vulcanization molding is not limited. In consideration of workability, it is desirable to have a granular shape at the time of blending. In the belt molded body, the water-soluble polymer does not need to retain the shape at the time of blending, and the shape may be changed during kneading or vulcanization molding. For example, by providing a step of kneading the rubber and water-soluble polymer at the melting point or softening point or higher before vulcanization molding, the water-soluble polymer can be polymer-alloyed and well dispersed. The friction transmission surface can be composed of a rubber composition having a sea-island structure in which rubber is a continuous layer and water-soluble polymer is a dispersed layer.

The rubber composition may contain a plasticizer having a solubility index (SP value) of 8.3 to 10.7 (cal / cm ³ ) ^1/2 . That is, the solubility index is larger than the solubility index of the ethylene / α-olefin elastomer (approximately 8.0 (cal / cm ³ ) ^1/2 ), that is, 8.3 to 10.7 (cal / cm ³ ) ^{1 /} By blending a material within the range of ² , the rubber surface bleeds, the friction coefficient can be reduced in the dry state, and uniform water wettability can be secured in the wet state to stabilize the friction coefficient. The stick-slip phenomenon can be suppressed by acting as a lubricant. The SP value is determined by SP = dΣG / M (d: density, G: molecular attractive constant, M: molecular weight).

Examples of the plasticizer having a solubility index in the range of 8.3 to 10.7 (cal / cm ³ ) ^1/2 include, for example, ethers, esters, ether esters, phthalic acid derivatives, adipic acid derivatives, Sebacic acid derivative-based, trimellitic acid derivative-based, and phosphoric acid derivative-based plasticizers can be used. Among these, ether ester plasticizers are preferably used because they have a moderate bleed effect and good wettability with water.

  Moreover, it is preferable that the compounding quantity of the said plasticizer shall be 10-25 mass parts with respect to 100 mass parts of ethylene * alpha-olefin elastomers. That is, when the blending amount is less than 10 parts by mass, the plasticizer is not sufficient as an amount for covering the belt surface, it is difficult to ensure uniform water wettability, and the effect as a lubricant is poor. On the other hand, if the blending amount exceeds 25 parts by mass, a conspicuous decrease in the surface friction coefficient is conversely observed, and there is a possibility that a problem such as extremely reduced wear resistance may occur. In view of preventing volatilization in a high temperature environment, the average molecular weight of the plasticizer is preferably 300 or more.

  And a rubber composition can be made to contain a short fiber. For example, short fibers selected as desired from polyamide, polyester, cotton, aramid, PBO and the like are mixed to improve the side pressure resistance of the compression layer 4 and to the surface of the compression layer 4 that is in contact with the pulley. Short fibers can be protruded to reduce the friction coefficient of the compression portion, thereby reducing noise during belt running. In particular, when at least one of an aramid short fiber and a polyamide short fiber is included, an effect of maintaining a low friction coefficient for a long time can be obtained. The aramid fiber has an aromatic ring in the molecular structure, and examples thereof include trade names Conex, Nomex, Kevlar, Technora and Twaron. In addition, since a short cotton fiber is poor in dispersibility, it is not preferable to mix in a large amount.

  The short fiber has a fiber length of 1 to 20 mm, and the addition amount is preferably 5 to 50 parts by mass with respect to 100 parts by mass of rubber. When the amount of the short fiber added is less than 1 part by mass, the rubber of the compression layer 4 tends to stick and wear, and when it exceeds 40 parts by mass, the short fiber is uniform in the rubber. Difficult to disperse. In order to improve the adhesion of the short fibers to the rubber of the compression layer 4, the short fibers are preferably subjected to an adhesion treatment with a treatment liquid containing an epoxy compound or an isocyanate compound or an RFL treatment liquid.

  In addition, an organic peroxide can be blended as a crosslinking agent in the rubber composition. Examples of the organic peroxide include dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5 -Dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5- (benzoylperoxy) hexane, 2,5-dimethyl-2,5-mono (t- Butyl peroxy) hexane and the like. This organic peroxide is preferably used alone or as a mixture in the range of 0.5 to 8 parts by mass with respect to 100 parts by mass of rubber. Of course, it is also possible to use a crosslinking agent other than the organic oxide.

  The rubber composition may contain 0.5 to 13 parts by mass of N, N′-m-phenylene dimaleimide and / or quinonedioxime with respect to 100 parts by mass of rubber. N, N′-m-phenylene dimaleimide and / or quinonedioxime acts as a co-crosslinking agent, and if less than 0.5 parts by mass, the effect of addition is not significant, and if it exceeds 13 parts by mass, tearing force and adhesion The force drops sharply. At this time, when N, N′-m-phenylene dimaleimide is selected as the co-crosslinking agent, the cross-linking density is high, the wear resistance is high, and the difference in transmission performance between water injection and drying is small. is there. Further, when quinone dioximes are selected, there is a feature that the adhesiveness with the fiber base material is excellent.

  Examples of quinone dioximes include p-benzoquinone dioxime, p, p'-dibenzoquinone dioxime, and tetrachlorobenzoquinone poly (P-dinitrobenzoquinone). In view of adhesiveness and crosslink density, benzoquinone dioximes such as p-benzoquinone dioxime and p, p'-dibenzoquinone dioxime are preferred.

  Moreover, inorganic fillers, such as carbon black, metal carbonate, metal silicate, can be mix | blended with the said rubber composition. Considering the reinforcing property, it is desirable that at least carbon black is contained.

Carbon black is not limited, it is preferable that the nitrogen adsorption specific surface area 20~150cm ² / g, DBP oil absorption amount is used which has the properties of 50~160cm ³ / 100g. Here, the nitrogen adsorption specific surface area (N ₂ SA) is a specific surface area of carbon black, and is measured according to JIS K 6217-2. The DBP oil absorption (dibutyl phthalate oil absorption) is a structure index and is measured according to JIS K 6217-4.

  Examples of the metal carbonate include calcium carbonate, and examples of the metal silicate include calcium silicate, potassium aluminum silicate, aluminum silicate, and magnesium silicate. More specifically, examples of aluminum silicate include clay, examples of magnesium silicate include talc, and examples of potassium aluminum silicate include mica. These can be used alone or in combination. Of these, calcium carbonate is desirable because it has good compatibility with rubber and does not adversely affect mechanical properties such as strength.

  The average primary particle size of the inorganic filler is preferably 0.01 to 3.00 μm. If it exceeds 3.00 μm, there is a problem that the durability of the belt is adversely affected. If it is less than 0.01 μm, the dispersibility is poor and the rubber physical properties may be uneven.

  In addition, normal rubber blends such as sliding agents such as graphite, molybdenum disulfide, and ultra-high molecular weight polyethylene, anti-aging agents, softeners, stabilizers, processing aids, and coloring agents, as necessary. What is used for a thing can be mix | blended.

  The adhesive layer 3 is desirably made of a blend rubber obtained by mixing ethylene / α-olefin rubber alone or a partner rubber made of other kinds of rubber as a rubber component. As the other rubber blended with ethylene / α-olefin rubber, butadiene rubber (BR), styrene / butadiene rubber (SBR), nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), chloroprene rubber (CR), Mention may be made of at least one rubber of butyl rubber (IIR) and natural rubber (NR). Of course, it is possible to use the same rubber composition as described above.

  The V-ribbed belt is not limited to the configuration shown in FIG. 1, and for example, a V-ribbed belt in which no adhesive layer is disposed, a V-ribbed belt in which rubber is exposed without attaching a canvas to the back, and the like belong to the technical scope of the present invention. . Hereinafter, these embodiments will be described with reference to the drawings.

  The V-ribbed belt 21 shown in FIG. 2 has a stretch layer 25 formed of a rubber composition with a back surface 28 provided with a flocking layer 24, and an adhesive layer 22 disposed below the stretch layer 25. The layer 26 is arranged. The core wire 23 is embedded in the main body along the longitudinal direction of the belt, and a part thereof is in contact with the stretched layer 25 and the remaining part is in contact with the adhesive layer 22. The compressed layer 26 is provided with a plurality of ribs 27 having a substantially triangular cross section extending in the belt longitudinal direction. Here, the short fibers contained in the compressed layer 26 exhibit a flow state along the rib shape, and the short fibers near the surface are oriented along the rib shape.

  A V-ribbed belt 31 shown in FIG. 3 has a configuration in which a back surface 38 is formed of a rubber layer containing a short fiber 34 and a compression layer 36 is disposed below the stretch layer 35. The core wire 33 is embedded in the main body along the longitudinal direction of the belt, and a part thereof is in contact with the stretch layer 35 and the remaining part is in contact with the compression layer 36. The compression layer 36 is provided with a plurality of ribs 37 having a substantially triangular cross section extending in the belt longitudinal direction, and a flocking layer 39 is provided on the rib surface. Here, the short fibers contained in the stretched layer 35 are oriented in a random direction.

  Here, the rubber composition and the core wire constituting the stretch layer, the compression layer and the adhesive layer can be the same as described above.

  FIG. 3 shows a configuration in which the stretch layer 35 is not composed of a canvas and is formed of a rubber composition containing short fibers. At this time, an uneven pattern is formed on the back surface in order to suppress abnormal noises when driving the back surface. Can be provided. Examples of the concavo-convex pattern include a knitted fabric pattern, a woven fabric pattern, a suede woven fabric pattern, and the like, and most preferably a woven fabric pattern. Moreover, as a short fiber, polyester, aramid, nylon, cotton, etc. can be mix | blended as desired.

  In FIG. 3, the short fibers contained in the stretched layer 35 are oriented in a random direction, but may be oriented in one direction such as in the belt width direction. In addition, when oriented in a random direction, there is a feature that the generation of cracks and cracks from multiple directions can be suppressed. At this time, if a short fiber (for example, a milled fiber) having a bent portion is selected as the short fiber, more It has a feature that it can withstand the force acting from the direction.

  In the case where the adhesive layer is not disposed as shown in FIG. 3, the core wire 33 is embedded in the belt body at the boundary region between the stretch layer 35 and the compression layer 36. At this time, considering the adhesiveness between the core wire 33 and the belt body, it is desirable that one of the stretched layer 35 and the compressed layer 36 is made of a rubber composition containing no short fibers.

  In FIG. 2, the stretch layer 25 has a structure in which the flocked layer 24 is provided on the surface of the rubber composition that does not contain short fibers, but the flocked layer is provided on the surface of the rubber composition that contains short fibers. Is also possible.

  In FIG. 2, the short fibers contained in the compressed layer 26 are in a flow state along the rib shape, but the short fibers may be oriented in the width direction.

  The compression layer may be composed of a plurality of rubber layers. Considering the balance of physical properties of the entire compression layer, the entire compression layer is not composed of a rubber composition containing a water-soluble polymer, but only the surface layer of the compression layer is composed of the rubber composition, and the inner layer is highly water-soluble. It is desirable that the rubber composition does not contain molecules. In this case, the thickness of the surface layer is preferably equal to or greater than the thickness assumed to be damaged by wear when the belt is run to the end of its service life.

  When the V-ribbed belt performs back surface transmission, the surface of the stretch layer can also be a friction transmission surface. Therefore, the stretch layer may be composed of the rubber composition of the present invention. That is, when the present invention is applied to a V-ribbed belt that performs back surface transmission, at least a part of the surface layer of the compression layer and / or the surface layer of the stretch layer may be formed of a specific rubber composition.

  Next, a method for manufacturing these V-ribbed belts will be described. Although it does not limit as a manufacturing method, For example, there exist the following methods.

  As a first method, first, a member constituting an extension layer and an adhesive rubber sheet constituting an adhesive layer are wound around a peripheral surface of a cylindrical molding drum, and then a cord made of a cord is spirally wound thereon. Then, a compressed rubber sheet constituting the compression layer is wound in order to form an unvulcanized sleeve, and then vulcanized to obtain a vulcanized sleeve. Next, the vulcanization sleeve is hung on a driving roll and a driven roll and travels under a predetermined tension, and the rotated grinding wheel is moved so as to abut on the traveling vulcanization sleeve to compress the sleeve. A surface of 3 to 100 grooves is polished on the surface at a time to form a friction transmission surface. The sleeve thus obtained is removed from the driving roll and the driven roll, the sleeve is hung on the other driving roll and the driven roll, traveled, cut into a predetermined width by a cutter, and finished into individual V-ribbed belts. .

  As a second method, after winding a compression rubber sheet constituting a compression layer and an adhesive rubber sheet constituting an adhesive layer around a cylindrical molding drum having rib markings on the peripheral surface, the core wire is spun, An unvulcanized sleeve is arranged by winding a member constituting the stretch layer. Thereafter, the unvulcanized sleeve is vulcanized while being pressed against the molding drum, whereby a rib is formed on the compression layer. The obtained vulcanized sleeve is formed with ribs. The rib surface is polished if necessary, and cut into a predetermined width to obtain individual V-ribbed belts.

  As a third method, after winding a member constituting an extension layer and an adhesive rubber sheet constituting an adhesive layer on a flexible jacket mounted on a cylindrical molding drum, spinning a core wire thereon Further, the compressed rubber sheets constituting the compression layer are sequentially wound endlessly to form an unvulcanized sleeve. Then, the flexible jacket is expanded, and the unvulcanized sleeve is pressed against an outer mold having an inscription corresponding to the rib portion, and vulcanized. The obtained vulcanized sleeve is formed with ribs. The rib surface is polished if necessary, and cut into a predetermined width to obtain individual V-ribbed belts.

  As a fourth method, after forming a first unvulcanized sleeve in which a compressed rubber sheet constituting a compression layer is disposed on a flexible jacket mounted on a cylindrical molding drum, the flexible jacket is The first unvulcanized sleeve is expanded and pressed against an outer mold having an inscription corresponding to the rib portion to produce a preform having the rib portion. Then, the inner mold is separated from the outer mold to which the preformed body is adhered, and then the member constituting the stretch layer and the adhesive rubber sheet constituting the adhesive layer are arranged on the inner mold, and the core wire is spun. A second unvulcanized sleeve is formed. Then, the flexible jacket is expanded, and the second unvulcanized sleeve is pressed from the inner peripheral side to the outer mold to which the preform is in close contact, and is vulcanized integrally with the preform. Ribs are formed on the obtained vulcanized belt sleeve, but the rib surface is polished if necessary and cut into a predetermined width to obtain individual V-ribbed belts.

  When the compression layer of the V-ribbed belt is composed of two layers, a surface layer and an inner layer, a compression rubber sheet having a two-layer structure of the surface layer and the inner layer is wound, or the surface compression rubber sheet and the inner layer compression rubber sheet are sequentially wound. It is necessary to form an unvulcanized sleeve in which a compressed layer having a two-layer structure of a surface layer and an inner layer is disposed by winding or the like. At this time, since the rib is formed by polishing in the first method, it is considered that the surface layer exists on the rib crest of the obtained V-ribbed belt, but the inner layer is exposed on the rib side surface and the rib bottom. Therefore, it is desirable that the V-ribbed belt composed of two layers of the surface layer and the inner layer is manufactured by the second method, the third method, or the fourth method.

  Further, the V-ribbed belt having no adhesive layer as shown in FIG. 3 can be obtained by manufacturing the above method without arranging an adhesive rubber sheet. Further, as shown in FIG. 2, the short fibers contained in the compressed layer 26 are in a flow state along the rib shape. The V-ribbed belt is manufactured by, for example, the second method, the third method, or the fourth method. Can be obtained. And the V-ribbed belt in which the short fibers contained in the compressed layer are oriented in the width direction can be obtained by, for example, the first method.

  Here, the rubber composition constituting the compressed rubber sheet (rubber composition constituting the friction transmission surface) can be prepared as follows. Specifically, each compounding agent and rubber are blended and kneaded using a kneader such as a Banbury mixer or a kneader. The kneading temperature at this time is preferably carried out at a temperature equal to or higher than the melting point or softening point of the water-soluble polymer. As a result, the water-soluble polymer is melted / softened, and can be well dispersed by forming a rubber and polymer alloy. The main kneading can be carried out in a plurality of times. And a compression rubber sheet can be produced by rolling the rubber composition prepared in this way.

  Although the present embodiment is an example in which the present invention is applied to a V-ribbed belt, the present invention is not limited to a V-ribbed belt but can be applied to other types of friction transmission belts.

  Hereinafter, a description will be given with specific examples.

Examples 1-3, Comparative Examples 1-4
A rubber composition was prepared according to the formulation shown in Table 1. Each compounding agent was mixed with EPDM using a Banbury mixer and kneaded at a temperature of 120 ° C. The obtained rubber composition was rolled with a calender roll to obtain a compressed rubber sheet. Here, as an evaluation of workability, the rubber sheet after rolling was visually observed to confirm the sheeting state. ○ indicates a state in which the rubber sheet is not torn or perforated, Δ indicates a state in which the rubber sheet is torn or perforated, and × indicates a state in which sheeting is impossible. These results are also shown in Table 1. The stretched rubber sheet was also prepared in the same manner as the compressed rubber sheet.

  Next, a V-ribbed belt was produced using these rubber sheets. In the V-ribbed belt, a cord made of a polyester fiber rope is embedded in the belt body, the back surface (extension layer) is formed of a rubber layer, and three rib portions are formed on the compression layer provided on the other surface side of the belt. It is arranged in the longitudinal direction. The compression layer and the stretch layer contain short fibers, and the short fibers are oriented in the belt width direction.

  As a belt manufacturing method, the following known methods were used. First, a stretched rubber sheet is wound around a flexible jacket mounted on a cylindrical molding drum, a polyester fiber cord is spun, and a compressed rubber sheet is wound around to form an unvulcanized belt sleeve. Then, the flexible jacket is expanded, the unvulcanized sleeve is pressed against an outer mold having a stamp corresponding to the rib portion, vulcanized, and the obtained vulcanized belt sleeve is cut into individual belts by a cutter. Thus, a V-ribbed belt was obtained. Using each of these V-ribbed belts, the sound resistance and heat durability were evaluated. The compressed layer surface and the stretched layer surface of the V-ribbed belts of Examples 1 to 3 and Comparative Examples 1 and 2 were confirmed to be composed of a rubber composition in which a water-soluble polymer was well dispersed by polymer alloying. Was confirmed.

Heat durability evaluation (heat resistance durability running test)
The running test machine used for the evaluation of the heat resistance durability test is configured by arranging a drive pulley (diameter 120 mm), a driven pulley (diameter 120 mm), an idler pulley (diameter 85 mm), and a tension pulley (diameter 45 mm) in this order. . Then, a V-ribbed belt is hung on each pulley of the testing machine, the wrapping angle around the idler pulley is 90 °, the ambient temperature is 120 ° C, the driving pulley is rotated at 4900 rpm, and the belt tension is 559 N / 3 rib. Then, a load was applied to the drive pulley and the V-ribbed belt was run for 500 hours, and the number of cracks generated in the compression layer was examined.

Pronunciation resistance evaluation (pronunciation limit tension test)
In the sound generation limit tension test, the obtained V-ribbed belt was suspended at a predetermined belt tension between a driving pulley having a diameter of 135 mm, a first driven pulley having a diameter of 112 mm, and a second driven pulley having a clutch mechanism having a diameter of 60 mm, Then, water was poured at 60 cc / min while rotating the drive pulley at 5,000 rpm, and the squeal generated when the second driven pulley was started to rotate and the tone generation limit tension which is the minimum tension of the belt at this time were measured. In addition, this test was implemented about the belt (new article) before the heat endurance test, and the belt (running running article) after the heat endurance test. The results are also shown in Table 1.

  As a result, in the examples, the sound production limit tension at the time of water injection is low for both new and run-in products, and the difference in sound production limit tension between the new and run-in products is small. I was able to find out. Furthermore, it has also confirmed that it has high heat durability. On the other hand, Comparative Example 1 showed no effect due to the blending of the water-soluble polymer, and Comparative Example 2 showed a decrease in heat resistance and workability although it was effective in sound resistance during water injection. In Comparative Example 3, the heat resistance and workability were extremely reduced, and it was confirmed that there was a problem in actual use. Furthermore, in Comparative Example 4, the sound generation limit tension at the time of water injection is high and the difference is large for both of the new conditioned traveling products, and the sound generation resistance is not sufficient, and the sustainability of the effect is poor. understood.

  The friction transmission belt according to the present invention can be attached to a drive device for automobiles or general industries.

It is a section perspective view of the V ribbed belt which is a friction transmission belt concerning the present invention. It is sectional drawing of another V-ribbed belt which is a friction transmission belt which concerns on this invention. It is sectional drawing of another V-ribbed belt which is a friction transmission belt which concerns on this invention.

Explanation of symbols

1 V-ribbed belt 2 Core wire 3 Adhesive layer 4 Compression layer 5 Stretch layer 6 Rib part

Claims (11)

  At least a part of the friction transmission surface is composed of a rubber composition containing 5 to 50 parts by mass of a water-soluble polymer having a melting point or a softening point of 80 ° C. or less with respect to 100 parts by mass of rubber. Friction transmission belt.   The friction transmission belt according to claim 1, wherein the rubber is mainly composed of an ethylene / α-olefin elastomer.   The friction transmission belt according to claim 1 or 2, wherein the water-soluble polymer has a melting point or softening point of 50 to 80 ° C.   The friction transmission belt according to claim 3, wherein the water-soluble polymer is polyethylene oxide.   The friction transmission belt according to any one of claims 1 to 4, wherein the friction transmission belt is a V-ribbed belt.   At least a part of the friction transmission surface is formed by vulcanization molding a rubber composition containing 5 to 50 parts by mass of a water-soluble polymer having a melting point or softening point of 80 ° C. or less with respect to 100 parts by mass of rubber. A method of manufacturing a friction transmission belt.   The method for producing a friction transmission belt according to claim 6, further comprising a step of kneading the rubber and the water-soluble polymer at the melting point or the softening point or higher before vulcanization molding.   The method for producing a friction transmission belt according to claim 6 or 7, wherein the rubber is mainly composed of an ethylene / α-olefin elastomer.   The method for producing a friction transmission belt according to claims 6 to 8, wherein the water-soluble polymer has a melting point or softening point of 50 to 80 ° C.   The method for producing a friction transmission belt according to claim 9, wherein the water-soluble polymer is polyethylene oxide.   The method for manufacturing a friction transmission belt according to any one of claims 6 to 10, wherein the friction transmission belt is a V-ribbed belt.

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