JPH07110900B2 - Phenolic resin molding material and V-belt using this material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a phenolic resin molding material and a V-belt used in a dry transmission in which a contact surface with a pulley is formed by using this material. .

(Prior Art) Currently, a belt-type continuously variable transmission is under development as a transmission for automobiles. This belt-type continuously variable transmission is configured by mounting a variable speed pulley having a variable groove interval on each of a drive shaft and a driven shaft and winding a V-belt between the two variable speed pulleys. To change the speed continuously.

As the V-belt, there is known a block V-belt in which a plurality of blocks made of a non-metallic material are engaged with a pair of endless tension bands (for example, JP-A-60-4).
9151 gazette). That is, each block has grooves formed on both sides thereof to be engaged with the tension band, and both side surfaces are inclined surfaces adapted to the pulley groove surface,
The inclined surface and the side surface of the tension band are substantially flush with each other to form the belt side surface. This one has better flexibility than conventional rubber V-belts and can withstand high lateral pressure.
Compared with metal V-belts, there are advantages such as weight reduction, no need for lubrication, and less noise.

Further, there is also known one in which a portion of the block which comes into contact with the pulley is formed of a phenolic resin molding material (see, for example, JP-A-63-34342). That is, this phenolic resin molding material is one in which a fibrous base material is contained in a matrix composed of a phenol resin and a rubber component, and a friction modifier is further compounded if necessary.

As the fibrous base material, organic fibers such as polyvinyl alcohol fibers, polyamide fibers, cellulosic fibers, polyester fibers, and aramid fibers, or inorganic fibers such as carbon fibers, glass fibers, metal fibers, and mineral fibers are used alone. Alternatively, they are used in combination as appropriate.
Further, as the friction modifier, fluorocarbon resin, graphite, molybdenum disulfide, carbon whiskers, etc. are used.

Therefore, this product has high heat resistance because the base is a phenol resin, and the rubber component and the fibrous base material contribute to the impact strength and the bending strength, so that the block V belt can be operated at high speed, Be able to withstand high temperature and heavy load.

(Problems to be solved by the invention) By the way, in the above-mentioned block, from the viewpoint of improving its durability and transmission, bending strength, impact strength,
It is required to improve mechanical properties such as fatigue strength and elastic modulus, to impart frictional wear characteristics such as improved wear resistance and adjustment of friction coefficient, and not to damage the pulley. Therefore, as the above-mentioned phenolic resin molding material, what matters should be the material to be filled,
In addition, its effect on the formability of the material must also be considered.

On the other hand, in the case of the conventional phenolic resin molding material, a suitable one for improving the above-mentioned properties is appropriately selected from various organic fibers and inorganic fibers, and the selected fibers are appropriately combined, and further However, there is a problem that it is actually difficult to comprehensively improve both the mechanical properties and the friction and wear properties described above.

That is, among the organic fibers, nylon 6 and nylon 6,6
Polyamide-based fibers such as, for example, have a large change in fine structure and molecular weight such as crystallinity and crystal grain size when wet and hot (when heat is applied in a high humidity state), and as a result, strength and melting point drop are likely to occur. It is not desirable as a highly hygroscopic phenolic resin molding material. Further, there is a problem that cellulosic rayon is also hydrolyzed and deteriorated when wet and hot. In the case of polyethylene terephthalate fiber, in addition to the above-mentioned problem of hydrolysis, there is a possibility of being attacked by ammonia generated in the molding process of the phenolic resin molding material.

In addition, polyvinyl alcohol fibers cannot be expected to have high physical properties at high temperatures.

Further, conventional aramid fibers such as polyparaphenylene terephthalamide fiber and polymetaphenylene isophthalamide fiber do not have sufficient moist heat resistance, and moreover, they are easily broken during the production of the molding material.

On the other hand, although the combination of glass fibers, metal fibers, mineral fibers and the like as the above-mentioned inorganic fibers is good in terms of strength, elastic modulus and heat resistance, the mating material is likely to be worn or damaged during sliding. Also, in the case of carbon fiber, although there is no problem of wear and damage to the mating material, there are various carbon fibers such as pitch type and PAN type which have different physical properties such as tensile strength and elastic modulus. It is difficult to comprehensively improve the above-mentioned mechanical properties and frictional wear characteristics even if the selection is made on the basis of.

Further, it is not preferable to fill the friction modifier with a large amount. That is, due to the use of a large amount of the friction modifier in relation to the fibrous filler, the total amount of the filler in the phenolic resin molding material becomes too large, and the dispersibility of these fillers deteriorates. In addition to the decrease in strength, the flowability of the material also deteriorates the moldability. On the other hand, it is not preferable to reduce the filling amount of the fibrous filler from the viewpoint of improving the mechanical properties.

The present invention has been made in view of the problems of the above-mentioned conventional techniques and the examination results thereof, and the problem is to use a phenolic resin molding material suitable for improving the above-mentioned physical properties and the material thereof. The purpose is to provide the V belt.

(Means for Solving the Problems) The present invention is directed to such problems by using carbon fibers and aramid fibers in order to comprehensively improve the above-mentioned mechanical properties and frictional wear characteristics from various fibers. Two fibers are selected and combined, and as the above-mentioned carbon fiber, one having optimum physical properties from the viewpoint of crystal structure, that is, one having an onion structure and a crystal layer thickness of 25 to 200 Å is adopted, and the degree of graphitization is high. The onion structure reduces the friction coefficient, and the cross-sectional morphology of the fiber is less likely to be destroyed even under high load. Therefore, the mechanical strength is maintained and the friction and wear characteristics are good (the mating material is not damaged and The coefficient is stable).

That is, the phenolic resin molding material according to the invention of claim (1) has 100 parts by weight of a matrix composed of 100 parts by weight of a phenolic resin and 0 to 20 parts by weight of acrylonitrile-butadiene rubber, and a carbon fiber and an aramid fiber. 25 to 60 parts by weight of a fibrous filler containing the above two fibers are blended, the carbon fiber has an onion structure, and the crystal layer thickness is 25 to 200Å.

Examples of the phenol resin include modified or unmodified novolac, resol or benzylic ether type phenol resin, and the like. Examples of the modified phenolic resin include alkyl modified phenolic resin and tall oil modified phenolic resin, and more preferred are cardol and the like, that is, cashew oil and cardol, anacardic acid and cardanol contained therein. Phenolic resins modified with at least one compound selected from

The modified and unmodified phenolic resins described above can be used alone or in combination of two or more kinds. Especially when the unmodified phenolic resin and the modified phenolic resin such as cardol are used together, the phase of the rubber component to be used is It is advisable to appropriately select the mixing ratio of the two in consideration of the solubility.

The matrix may be composed of a phenol resin alone, or may be composed of a phenol resin and acrylonitrile-butadiene rubber. In that case, it is preferable to use the acrylonitrile-butadiene rubber in the range of 3 to 20 parts by weight based on 100 parts by weight of the phenol resin. If the blending amount exceeds 20 parts by weight, good results cannot be obtained in terms of flexural strength, flexural modulus and wear resistance.

Further, the modified phenol resin such as the above cardol is
It is suitable when the matrix is formed with an acrylonitrile-butadiene rubber. That is, it has good compatibility with acrylonitrile-butadiene rubber,
When such a rubber constitutes a part of the matrix, the bending strength and the bending elastic modulus can be increased while maintaining the high impact strength. In the case of modifying with cardole or the like alone or in combination, it is preferable to use 10 to 100 parts by weight, preferably 15 to 70 parts by weight with respect to 100 parts by weight of phenols such as phenol, cresol and resorcin. For example, when cashew oil is used as cardol or the like, if it is less than 10 parts by weight, the compatibility with the rubber component is not so good, and the bending strength and impact strength of the molding material cannot be expected to be improved, which is not preferable. On the other hand, if it exceeds 100 parts by weight, the bending strength of the molding material is lowered and the heat resistance is also deteriorated.

Examples of the acrylonitrile-butadiene rubber include unvulcanized or vulcanized acrylonitrile-butadiene rubber (NBR), carboxy-modified acrylonitrile-butadiene rubber (C-NBR), and amino-modified acrylonitrile-butadiene rubber (A-NBR). Suitable, these can be used alone or in combination. That is, they have a relatively high polarity, a high compatibility with a phenolic resin which is a polar polymer, and a high strength because they are uniformly dispersed in this resin. Further, in the case of carboxy-modified acrylonitrile-butadiene rubber, it is possible to increase the usage rate of the unmodified phenol resin in the combined use of the modified phenol resin / unmodified phenol resin, and further, good results can be obtained even with the unmodified phenol resin alone. Like Further, this rubber may be crosslinked during the kneading and curing process of the phenol resin by adding a vulcanizing agent such as sulfur, peroxide and a resin vulcanizing agent, a vulcanization accelerator and a vulcanization aid.

The carbon fiber, aramid fiber and polyvinyl alcohol fiber as the fibrous filler are used in the form of fiber, twisted yarn, chip-like cloth and cloth, and the fiber length thereof is not particularly limited, but is about 1 to 10 mm. preferable. Further, the twisted yarn, the chip-shaped cloth and the cloth may be used as they are, but by fixing them with an adhesive, the twisted yarn, the chip-shaped cloth and the cloth are prevented from unraveling during the production of the material, and these fibers are also used. It is possible to increase the tensile strength and the strength in the longitudinal and lateral directions.

The ratio of the above fibrous filler to 25 to 60 parts by weight is 25
It is difficult to improve the above-mentioned physical properties if less than parts by weight,
On the other hand, if it exceeds 60 parts by weight, the dispersibility of the fibrous filler will be deteriorated, each physical property will be deteriorated, and the flow of the material at the time of molding will be deteriorated.

Thus, the carbon fiber having the onion structure can be obtained by a non-graphitizable system (for example, PAN system). And, the onion structure having a high degree of graphitization reduces the friction coefficient and maintains good mechanical strength and friction wear characteristics even under a high load as compared with the radial structure obtained by the pitch system etc. . In other words, in the case of a radial structure, under high load part of the fiber easily falls off from the central part of the fiber in the radial direction, it is difficult to maintain mechanical strength, and there is a boundary between this missing part and the other part. It has an angular shape and adversely affects the friction and wear characteristics, but in the case of the onion structure, the cross-sectional shape of the fiber is not easily destroyed even under high load, and there is no problem of chipping of the fiber in the radial direction. Moreover, even if a part of the surface is peeled off, it has almost no effect on the mechanical strength and the friction and wear characteristics.

Further, the crystal layer thickness of the carbon fiber corresponds to the degree of graphitization, the crystal layer thickness of 25 ~ 200 Å, the friction coefficient is high below 25 Å can not be obtained good friction wear characteristics, On the other hand, if it exceeds 200Å, the friction coefficient tends to be too low, and the reinforcing effect is also reduced.

The phenolic resin molding material in the present invention can be manufactured by a usual method. For example, a phenolic resin and, if necessary, a curing agent and an acrylonitrile-butadiene rubber are mixed, and a fibrous filler composed of two fibers of carbon fiber and aramid fiber is added to 100 weight of this matrix.
25 to 60 parts by weight are blended and uniformly dispersed and mixed with a Henschel mixer or the like, and then kneaded with a hot roll to form a sheet.
A phenolic resin molding material which can be molded is obtained by crushing, crushing or granulating the obtained sheet material.

The method for molding the phenolic resin molding material is not particularly limited, and an arbitrary method can be used among the commonly used methods.

In order to crosslink the rubber component, an appropriate amount of the crosslinking agent and the crosslinking accelerator may be added to the unvulcanized rubber, and the mixture may be kneaded with a roll and then mixed with the phenol resin material.

The phenolic resin molding material according to the invention of claim (2) comprises 100 parts by weight of a phenolic resin and acrylonitrile-
Matrix consisting of 0 to 20 parts by weight of butadiene rubber
Fibrous filler 25 consisting of 3 fibers of carbon fiber, aramid fiber and polyvinyl alcohol fiber per 100 parts by weight
It is characterized by being mixed with 60 parts by weight, the carbon fiber has an onion structure, and the crystal layer thickness is 25 to 200Å.

In the phenolic resin molding material according to the invention of claim (3), the aramid fiber in the invention of claim (1) or (2) has the formula It is characterized by being represented by.

The phenolic resin molding material according to the invention of claim (4) is the same as that of the invention of claim (1), (2) or (3), wherein 1 part of the inorganic friction modifier is added to 100 parts by weight of the matrix.
It is characterized by being mixed up to 25 parts by weight.

Suitable examples of the inorganic friction modifier include graphite, molybdenum disulfide, carbon whiskers, and the like, and powdery substances are usually used. If the amount of the friction modifier is more than 25 parts by weight, the friction coefficient becomes too low and it is not suitable for a power transmission material such as a V-belt.

The invention of claim (5) is a V-belt, comprising an endless tension band and a plurality of blocks provided on the tension band at a substantially constant pitch in the belt longitudinal direction, and at least the pulley of the block. The portion that comes into contact with is formed of the phenolic resin molding material according to any one of claims (1) to (4).

(Function) In the phenolic resin molding material according to claim (1),
Since the fibrous filler for the rigid phenolic resin matrix is a combination of two fibers, carbon fiber and aramid fiber, not only the flexural strength and impact strength of the molded body but also the elastic modulus and abrasion resistance requirements, It is possible to satisfy the requirement that the mating material of the molded body is not damaged at both normal temperature and high temperature.

That is, the carbon fiber, the crystal structure is an onion structure, since the crystal layer thickness is 25 ~ 200 Å, due to its high tensile strength and tensile elastic modulus, to increase the bending strength and bending elastic modulus of the molded body. In addition, when the molded product is used as a block of a block V-belt, the wear is prevented while the wear is prevented by a proper friction coefficient and wear resistance. This characteristic can be maintained even below. Of course, the mating material will not be damaged when the molded body slides. Further, since this carbon fiber has high heat resistance, it is effective in maintaining such characteristics at high temperatures.

By the way, if the crystal structure is radial even if it has a high elastic modulus, the fibers are crushed into an angular shape due to the shearing force at the time of kneading the material and the force received by the sliding surface, so that high abrasion resistance is obtained. Things will be difficult.

Aramid fiber improves bending strength and flexural modulus at room temperature, and improves impact strength that cannot be obtained with the above carbon fiber, and also contributes to improvement in wear resistance, and the problem of damage to the mating material Absent.

Therefore, by combining these two fibers, the aramid fiber improves the impact strength at room temperature, the bending strength, the bending elastic modulus, and the abrasion resistance without damaging the partner material as a molded body, and Therefore, the bending strength, bending elastic modulus, and wear resistance at high temperatures can be sufficiently maintained even under a high load. And, as described above, the carbon fibers contribute to the improvement of the friction and wear characteristics of the molded body,
The amount of the friction modifier to be filled can be reduced if necessary.

Further, in the invention of claim (1), when the matrix contains acrylonitrile-butadiene rubber, the impact strength can be further enhanced.

In addition, when the fibrous filler is a combination of two fibers of carbon fiber and polyvinyl alcohol fiber, it is difficult to obtain high impact strength, and in the case of a combination of two fibers of aramid fiber and polyvinyl alcohol fiber, good friction and wear are obtained. It becomes difficult to obtain properties and high strength at high temperatures.

In the phenolic resin molding material according to claim (2),
The fibrous filler for the rigid phenolic resin matrix consists of a combination of three fibers, carbon fiber, aramid fiber and polyvinyl alcohol fiber, but polyvinyl alcohol fiber has good adhesiveness with phenol resin, The flexural strength and flexural modulus at that time are improved more than the aramid fiber, and the impact resistance is also improved. This fiber, like the carbon fiber, does not damage the mating material.

In the phenolic resin molding material according to claim (3),
The aramid fiber, 3,4'-diamide diphenyl ether copolymer fiber, is due to the presence of the ether bond,
For example, the strength, elastic modulus, impact strength, chemical resistance, and heat resistance of the molded body can be improved as compared with polyparaphenylene terephthalamide, which is the same aramid fiber. Incidentally, in the case of the above-mentioned other polyaraphenylene terephthalamide as an aramid fiber, there is also a problem of hydrolysis during wet heat.

In the phenolic resin molding material according to claim (4),
Since the inorganic friction modifier is blended, it is possible to reduce the friction coefficient of the obtained molded product and suppress the noise caused by sliding with the mating material. In particular, since the friction modifier of the present invention is an inorganic one having a high heat resistance, the friction modifier, together with the above-mentioned carbon fibers, gives the molded article good friction and wear characteristics even at high temperatures. Moreover, this inorganic friction modifier also contributes to the reinforcement of the molded body.

In the V-belt according to claim (5), since the portion of the block that comes into contact with the pulley is formed of the phenolic resin molding material according to any one of claims (1) to (4), its bending strength and impact Mechanical properties such as strength, fatigue strength and elastic modulus are improved, and the friction and wear characteristics are improved so that the pulley is not damaged.

(Effect of the invention) According to the invention of claim (1), the combination of two fibers, carbon fiber and aramid fiber, has high impact strength, bending strength and flexural modulus, and is excellent in wear resistance. It becomes possible to obtain a molded product which is less likely to be deteriorated in physical properties even under a high load and which is less likely to be damaged by sliding of a mating material. For example, as a molding material for a V-belt, a gear, a cam or a pulley. Can be used as a power transmission material or a molding material for a sliding member.

According to the invention of claim (2), the combination of the three fibers of carbon fiber, aramid fiber and polyvinyl alcohol fiber is combined with the phenolic resin molding material of claim (1) without using a large amount of aramid fiber. It is possible to obtain the same effect.

According to the invention of claim (3), since the aramid fiber is the 3,4-diamidophenyl ether copolymer fiber, the strength, elastic modulus, and
Impact strength, chemical resistance and heat resistance can be improved.

According to the invention of claim (4), by the inorganic friction modifier,
Together with the carbon fiber, the friction and wear characteristics of the molded body can be made good not only at room temperature but also at high temperature, and the strength characteristics of the molded body can be improved.

According to the invention of claim (5), since the portion of the block that comes into contact with the pulley is molded from each of the phenolic resin molding materials of claims (1) to (4), the V-belt has high temperature, high speed, Alternatively, it can be used under a high load, and the durability and transmission efficiency of the V-belt can be improved without damaging the pulley.

(Examples) Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

First, a preferable V-belt structure will be described.

As shown in FIGS. 1 and 2, the V-belt 1 includes a pair of endless tension bands 2 and 3 and a plurality of blocks locked to the tension bands 2 and 3 at a constant pitch in their longitudinal direction. 4 and.

Further, each block 4 is molded with a phenolic resin molding material described later, and engaging grooves that open to the side surfaces 4a and 4b are formed on the side portions, and the upper surface and the lower surface of each engaging groove are formed. A convex portion 6 having a mountain-shaped cross section and a curved convex surface 7 are formed.

The tension bands 2 and 3 are cores 9 and 9 formed by twist-bonding organic fibers such as polyester and aramid or inorganic fibers such as steel, glass and carbon, and a rubber member 10 that holds the cores 9 and 9. , 11 and woven fabrics 12, 12 and 13, 13 embedded in the vicinity of the upper and lower surfaces and made of organic fibers such as 6,6 nylon and aramid which have excellent wear resistance. Also, the tension band
The upper surface and the lower surface of 2, 3 are provided with a convex portion 6 provided in the engaging groove of each block and a concave portion that engages with the curved convex surface 7 (only the concave portions 3a, 3b for the tension band 3 are shown). .

In FIG. 1, the convex portion 6 of the block 4 and the concave portion 3 of the tension bands 2 and 3 are shown.
Although the block 4 and the tension bands 2 and 3 are locked in the belt longitudinal direction by the engagement with a and 3b, conversely, a concave portion is formed on the block side and a convex portion is formed on the tension band side. May be engaged and locked.

Next, the physical properties of the phenolic resin molding material described below were measured according to the methods described below.

(1) Impact strength, flexural strength and flexural modulus JIS K6911 Here, the impact strength is the Izod impact strength with notch, and the test piece used was one provided with a notch at the time of molding by a mold. The flexural strength and flexural modulus were measured using a 10 mm square rod at a fulcrum distance of 64 mm and a load speed of 2 mm / mm.

(2) Friction coefficient and specific wear amount Suzuki type thrust friction and wear test Counterpart material SS41 Surface pressure 60kg / cm ² Sliding speed 5cm / sec V: Abrasion amount (mm ³ ) P: Test load (kg f) L: Sliding distance (km) Further, the belt durability test, transmission capacity test, and noise test were performed under the following belt specifications and test conditions.

(1) Belt dimensions Block thickness (4.8 mm) Mounting pitch (5.0 mm) Upper width (45 mm), angle 26 ° Belt circumference 750 mm (150 blocks) Block is a reinforcing member made of 2 mm thick aluminum alloy It is insert molded. (Not shown) (2) Belt transmission capacity test As shown in FIGS. 3 (a) and 3 (b), a sample was placed between the drive pulley 21 (pitch diameter 70 mm) and the driven pulley 22 (pitch diameter 160 mm). Winding belt 23, drive pulley speed 2500rp
The slip ratio was measured by changing the transmission torque at m and an axial load of 250 kg. From the transmission torque when the slip ratio is 2%,
The ST value was calculated and used as the transmission capacity.

ST = T / r ・ r θ T: Transmission trickle at 2% slip (kg ・ m) r: Effective radius (m) θ: Belt wrap angle (radian) (3) Belt durability test Same as the transmission capability test With pulley layout, drive pulley rotation speed 2500 rpm, shaft load 250 kg, input torque 4.5 kg
The test was conducted at an ambient temperature of 90 ° C. while the belt was running.

(4) Belt noise test Same layout as the transmission capacity test, drive pulley rotation speed
The total noise level was measured by the sound level meter 24 at a predetermined position (L ₁ = 50 mm, L ₂ = 100 mm) while traveling at 1000 rpm, an axial load of 100 kg, and no load.

<Manufacture of modified phenolic resin> Phenol 100 parts by weight 92% Paraformaldehyde 87 parts by weight Cashew oil (Kardalite D-10, made by Ito Essential Oil) 40
Parts by weight Oxalic acid 0.5 parts by weight All of the above raw materials are placed in a four-necked flask equipped with a thermometer, an agitator and a condenser, the contents are heated to 120 ° C and completely dissolved, and then refluxed at 100 ° C for 3 hours. The condensation reaction was performed below. Then, the temperature was raised to 200 ° C. under normal pressure for dehydration, and the contents were taken out from the flask and cooled to obtain a cashew oil-modified phenol resin. The softening point of the obtained resin is 60 ° C, and the flow with 10% hexa is 67 mm.
The gel time was / 125 ° C and the gel time was 40 seconds / 150 ° C.

[Example 1] Modified phenol resin 77 parts by weight Hexamethylenetetramine 14 〃 NBR 9 〃 Calcium carbonate 13 〃 Calcium stearate 2 〃 Carbon fiber A 27 〃 Aramid fiber 25 〃 Graphite (inorganic modifier) 18 〃 NBR is acrylonitrile- It is butadiene rubber. The carbon fiber A is PAN-based and has a crystal layer thickness L.
It has an onion structure with c = 25Å (see Table 3).
Aramid fiber has a fiber length of 3 mm, a tensile strength of 24 g / denier and a strength of 37 g.

The crystal layer thickness Lc is obtained by the following formula by the X-ray diffraction method.

Lc = 0.9λ / β cos θ λ; X-ray wavelength β; Spread of reflection based on crystal size θ; Diffraction angle Further, aramid fiber is Teijin Ltd. Technora (3,
4'-diamidophenyl ether copolymer fiber) was surface-treated with an epoxy resin before use.

Uniformly disperse and mix the above compound with an appropriate amount of solvent in a Henschel mixer, and then on a hot roll (95 ° C / 85 ° C) for 4-5
The mixture was kneaded for minutes, and taken out as a sheet. This sheet material was cut into an appropriate size to obtain a moldable phenolic resin molding material.

The molding material was transfer-molded by an ordinary method to prepare test pieces and blocks for the test, and the physical properties were measured and the performance test was performed.

Examples 2-12 The formulations of Examples 2-12 are shown in Tables 1 and 2 along with those of Example 1 above. The characteristics of the formulation of each example are as follows.

In Example 2, the matrix is composed of novolac phenol resin and hexamethylene tetramine, and Examples 3 to
Reference numeral 12 is a resin component of the matrix which is the above-mentioned modified phenolic resin with cashew oil.

In Examples 2 to 12, three fibers of carbon fiber, aramid fiber and polyvinyl alcohol fiber are used as the fibrous filler. Polyvinyl alcohol fiber has a fiber length of 3 mm, a tensile strength of 7.8 g / denier and a strength of 46.8 g.

Examples 3, 6 to 9, 11, and 12 have NBR, Examples 4 and 10 have carboxy-modified NBR, and Example 5 has amino-modified NBR as the rubber component of the matrix.

Further, Examples 2 to 10 use the same carbon fiber A as Example 1, Example 11 is carbon fiber B having an onion structure and a crystal layer thickness of 75Å, and Example 12 is carbon fiber having an onion structure and a crystal layer thickness of 100Å. The fiber C is used (see Table 3).

On the other hand, Examples 6 and 7 have small and large amounts of filler, Example 8 has large amount of carbon fiber A in the fibrous filler, and Example 9 has fibrous filler. The ratio of aramid fiber is increased. Examples 2-9,1
1, 12 use graphite as a friction modifier, and Example 10 uses PTFE instead of graphite as a friction modifier.
(Polytetrafluoroethylene) is used.

For these Examples 2 to 12, molding materials were prepared in the same manner as in Example 1, and the same physical property measurements and performance tests were performed.

The results of physical property measurements and performance tests of Experimental Examples 1 to 12 are shown in the lower column of Table 1.

[Comparative Examples 1 to 8] Table 2 shows the composition, the results of measuring physical properties and the results of performance tests of Comparative Examples.
It is as shown in Nos. 1 and 2. Preparation of molding material, preparation of test pieces and blocks, and measurement of physical properties and performance test are the same as in the examples. The glass fibers used were those surface-treated with a silane coupling agent (carbon fibers
See Table 3 for D and E).

Consider the above results for the examples and comparative examples.

Example 1 is an example in which the fibrous filler is composed of carbon fibers and aramid fibers, and because it contains a large amount of carbon fibers without containing polyvinyl alcohol fibers, it has good bending strength and bending elastic modulus, and particularly, such physical properties at high temperatures. In addition, the friction and wear characteristics are excellent, and the impact resistance is good due to the large amount of aramid fiber.

Example 2 is an example in which the matrix does not contain rubber, and the fibrous filler is composed of three fibers, that is, carbon fiber, aramid fiber and polyvinyl alcohol fiber, and the impact resistance is different from that of other examples because rubber is not contained. It is lower than
Other physical properties and performances show good results.

In Example 3, the matrix is a cashew oil-modified phenolic resin, NBR and an additive (hexamethylenetetramine).
In this example, the impact resistance is better than that of Example 2 because of the inclusion of rubber, but the physical properties other than friction and wear characteristics are slightly deteriorated.

Example 4 is an example in which a carboxy-modified NBR is used instead of the NBR of Example 3, but the flexural modulus and the belt transmission capacity are improved, although the impact resistance is slightly lowered.

Example 5 is an example using amino-modified NBR, but the results are the same as in Example 4, and there is no difference between carboxy-modified NBR and amino-modified NBR.

Although Example 6 is an example in which the amount of the filler is reduced as a whole (excluding calcium stearate) and Example 7 is increased, the physical properties generally reflect some of the above fillers.

Example 8 is an example in which the filling ratio of the carbon fiber A is increased, but although the impact resistance is lower than that in Example 3, the bending strength and bending elastic modulus are improved, and the dynamic friction coefficient and the specific wear amount are increased. Has been reduced. From this, it can be seen that the carbon fiber A is effective for improving other physical properties except impact resistance, but conversely, it is not preferable to reduce the amount of aramid fiber in terms of impact resistance. Recognize.

Example 9 is an example in which the filling ratio of the aramid fiber is increased, but the impact resistance and abrasion resistance are better than those of Example 3, and the aramid fiber is effective in improving both physical properties. Recognize.

In Example 10, PTFE was used as the friction modifier, but the physical properties other than impact resistance were deteriorated.

Example 11 is an example in which B having a crystal layer thickness thicker than that of carbon fiber A is used as the carbon fiber, and Example 12 is an example in which C having a larger crystal layer thickness is used. By comparison, although the impact strength and the bending strength are slightly lowered, the friction and wear characteristics are gradually improved and the bending elastic modulus is gradually increased. This means that a large crystal layer thickness means a high degree of graphitization, which lowers the coefficient of friction, but in the case of the onion structure that occurs in a non-graphitizable system, the development of graphite crystals It is recognized that the cross-sectional morphology of the fibers is less likely to be destroyed. That is,
It is recognized that the fracture resistance of the cross-sectional morphology contributes to the wear resistance and also to the tensile modulus, and thus the bending modulus.

Next, looking at Comparative Examples, Comparative Example 1 shows NBR in the matrix.
Although the amount is increased and only the aramid fiber is used as the fibrous filler and the carbon fiber is not used, the impact resistance is better than those of the examples, but other physical properties and the belt transmission ability are low. The wear length on one side of the block is also long.
Therefore, it can be seen that increasing the NBR and not filling the carbon fiber do not bring good results.

Comparative Example 2 is different from Comparative Example 1 in that two fibers of aramid fiber and polyvinyl alcohol fiber were used as the fibrous filler, but it can be seen that there is no great difference in the result even if the polyvinyl alcohol fiber is filled. .

Comparative Example 3 is an example in which only polyvinyl alcohol fiber is used as the fibrous filler, but it is understood that the polyvinyl alcohol fiber cannot be expected to greatly improve the physical properties.

Comparative Example 4 is an example in which glass fiber was used in place of the carbon fiber of Example 2, but the abrasion resistance was greatly reduced, and thus the carbon fiber increased in bending strength and bending elastic modulus. At the same time, it can be seen that it is effective in improving wear resistance.

Comparative Examples 5 and 6 are an example in which the amount of the fibrous filler was decreased and an example in which the amount was increased, but when the amount was decreased, the strength decreased, and conversely, when the amount increased, the strength decreased. This is because as a result of the increase in the amount of the fibrous filler, the dispersibility thereof was deteriorated, and further, the flow of the material during molding was also deteriorated.

Comparative Examples 7 and 8 use D and E having a pitch-based radial structure as carbon fibers, but when compared with Examples 3, 11 and 12, impact strength and friction wear characteristics are low. .
Therefore, from the results of Examples 3, 11, 13 and Comparative Examples 7, 8, it can be seen that it is better to use the one having an onion structure as the carbon fiber, which means that the carbon fiber having the radial structure has an onion structure. Compared with this, it is considered that the fibers are easily crushed by the shearing force at the time of kneading the materials and the force received by the sliding surface, and the crushing results in an angular shape.

[Brief description of drawings]

1 is a side view of a V-belt using a phenolic resin molding material according to the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIGS. 3 (a) and 3 (b) are tests. It is a principal part explanatory drawing of a method. 1 …… V belt, 2,3 …… tension band, 4 …… block, 21
...... Drive pulley, 22 …… Drive pulley, 23 …… Sample belt, 24 …… Noise meter.

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Claims (5)

[Claims] 1. A fibrous filler containing two fibers, carbon fiber and aramid fiber, in an amount of 25 to 60 parts by weight per 100 parts by weight of a matrix consisting of 100 parts by weight of a phenol resin and 0 to 20 parts by weight of an acrylonitrile-butadiene rubber. Parts, the carbon fiber has an onion structure, and the crystal layer thickness is 25 to 200Å. 2. A fibrous filler composed of 100 parts by weight of a matrix composed of 100 parts by weight of a phenolic resin and 0 to 20 parts by weight of an acrylonitrile-butadiene rubber, and 3 fibers of carbon fiber, aramid fiber and polyvinyl alcohol fiber. A phenolic resin molding material comprising 25 to 60 parts by weight, wherein the carbon fiber has an onion structure and a crystal layer thickness of 25 to 200Å. 3. The aramid fiber has the formula The phenolic resin molding material according to claim 1, which is represented by the formula (1). 4. An inorganic friction modifier is blended in an amount of 1 to 25 parts by weight with respect to 100 parts by weight of the matrix.
The phenolic resin molding material according to any one of (3). 5. An endless tension band and a plurality of blocks provided on the tension band at a substantially constant pitch in the longitudinal direction of the belt, and at least a portion of the block that contacts the pulley. ) To (4), a V-belt formed of the phenolic resin molding material according to any one of (1) to (4).