JP2002194144A - Transmission belt and hydrogenated nitrile rubber composition for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt which is improved in a fatigue property under a low temperature environment and maintains usual properties such as a harness and a modulus at an enough level for using as a belt and has no problem concerning bleeds. SOLUTION: The hydrogenated nitrile rubber composition comprises 100 pts.wt. of a hydrogenated nitrile rubber containing 10-30% of an acrylonitrile bonded units, 10-50 pts.wt. of plasticizer and 40-100 pts.wt. of carbon black, and a weight ratio of the plasticizer to the carbon black is between 10:40 and 50:100. The transmission belt 1 is made of the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogenated nitrile rubber composition and a belt using the same, and more particularly, to a belt made of a hydrogenated nitrile rubber having improved cold resistance without deteriorating various physical properties of the belt. And a rubber composition.

[0002]

2. Description of the Related Art In recent years, the quality required of power transmission belts has become severer year by year. Above all, a power transmission belt used in an automobile engine must be able to withstand the temperature in an engine room, and originally had a severe environmental temperature. Recently, there has been a tendency to save space and downsize the engine, and the engine room has become quite narrow. The temperature in the engine room is in the direction of rising further, and the transmission belt can withstand extremely high temperatures. Is needed.

[0003] When a car is used particularly in a cold region such as Northern Europe, the belt is left in an extremely low temperature state while the engine is stopped at night, for example. The part that was hardened at a low temperature with the bent part bent was sharply stretched at the start of the engine in the morning, and that part was severely fatigued, causing cracks early, and the cracks that occurred were cut and expanded. There is a growing possibility that such a problem will occur.

On the low-temperature side, adaptability to severer environments has been required. In order to improve the cold resistance of the hydrogenated nitrile rubber, the amount of acrylonitrile bonds as disclosed in, for example, JP-A-1-226443 is reduced and the third component (fluorine-containing vinyl monomer) is copolymerized. Polymers with improved cold resistance have also been developed.

As another means for improving cold resistance, a method of filling a plasticizer as disclosed in JP-A-6-107858 can be considered.

[0006]

However, the use of the above-mentioned cold-resistance-improving polymer has certainly improved the cold-resistance, and has better physical properties in a low-temperature environment than in the case of using a conventional hydrogenated nitrile rubber. However, it is still not cold resistant enough to be used as a power transmission belt.

[0007] In addition, the method of filling a plasticizer for the purpose of improving cold resistance also requires a considerably high filling, and while the cold resistance is improved, physical properties such as hardness and modulus are reduced, and the plasticizer is removed from the belt. Bleeding.

Accordingly, the present invention relates to a belt and a rubber composition containing hydrogenated nitrile rubber as a main component, which greatly improve cold resistance and do not reduce physical properties such as hardness and modulus. The purpose is to provide.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a plasticizer is added to 100 parts by weight of a hydrogenated nitrile rubber having an acrylonitrile bond amount of 10 to 30%. ５０50 parts by weight and carbon black in an amount of 40 to 100 parts by weight, and the weight ratio of the plasticizer to the carbon black is in the range of 10:40 to 50: 100. And

As described above, the amount of acrylonitrile bond
The hydrogenated nitrile rubber of 30% to 30% has improved cold resistance, and the amount of the plasticizer is set to 10 to 50 parts by weight, which is larger than the usual amount, so that it is sufficiently flexible even at extremely low temperatures. It is possible to obtain a belt having good properties and having little fatigue even if it is bent and stretched rapidly. And
40 to 40 times more carbon black than usual
By blending 100 parts by weight, it is possible to prevent bleeding of the plasticizer blended in a large amount as described above, and to provide a material which can withstand use as a belt without deteriorating physical properties such as hardness and modulus of the belt. can do.

In the second aspect, the hydrogenated nitrile rubber 100
The transmission belt has a blending amount of the plasticizer of 20 to 40 parts by weight with respect to part by weight. 20 to 40 plasticizer
By setting the amount by weight, the effect of improving the cold resistance by the plasticizer is obtained, and the blending amount is too large, and the bleeding of the plasticizer, and the physical properties such as hardness and modulus are not reduced, so that the range is more appropriate. It can be said.

In the third aspect, the hydrogenated nitrile rubber 100
50 to 80 parts by weight of carbon black based on parts by weight
The transmission belt is a weight part. By setting the blending amount of carbon black to 50 to 80 parts by weight, the problem of bleeding of the plasticizer can be sufficiently suppressed, and the belt becomes too hard due to excessive blending of carbon black, and conversely, cracks may occur. No problem.

According to a fourth aspect, the acrylonitrile bond amount is 1
10 to 50 parts by weight of a plasticizer and 40 to 40 parts by weight of carbon black with respect to 100 parts by weight of a hydrogenated nitrile rubber of 0 to 30%.
A hydrogenated nitrile rubber composition for a power transmission belt comprising 100 parts by weight of a hydrogenated nitrile rubber composition in which a weight ratio of a plasticizer and carbon black is in a range of 10:40 to 50: 100. Things.

As in the first aspect, the hydrogenated nitrile rubber having an acrylonitrile bond content of 10 to 30% has improved cold resistance, and the compounding amount of the plasticizer is larger than that of the normal compounding amount by 10 to 50%. By using parts by weight, it is possible to obtain a belt having sufficient flexibility even at extremely low temperatures and having little deterioration even if it is rapidly bent and stretched. By blending 40 to 100 parts by weight of carbon black, which is also larger than the usual blending amount, bleeding of the plasticizer blended in a large amount as described above can be prevented, and physical properties such as hardness and modulus of the belt also decrease. A belt that can be used as a belt without causing the belt to be used can be provided.

According to a fifth aspect of the present invention, there is provided a hydrogenated nitrile rubber composition for a power transmission belt in which a blending amount of a plasticizer is 20 to 40 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. By setting the blending amount of the plasticizer to 20 to 40 parts by weight,
It can be said that the effect of improving the cold resistance by the plasticizer is obtained, and that the blending amount is too large and the bleeding of the plasticizer and the decrease in physical properties such as hardness and modulus are within a more appropriate range.

According to a sixth aspect of the present invention, there is provided a hydrogenated nitrile rubber composition for a power transmission belt in which the compounding amount of carbon black is 50 to 80 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. By setting the blending amount of carbon black to 50 to 80 parts by weight, the problem of bleeding of the plasticizer can be sufficiently suppressed, and the belt becomes too hard due to excessive blending of carbon black, and conversely, cracks may occur. No problem.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a hydrogenated nitrile rubber composition which maintains the proper range of properties such as hardness and modulus for use as a belt, although the cold resistance is greatly improved. And a plasticizer is used in an amount of 10 to 50 parts by weight, more preferably 20 to 40 parts by weight, and carbon black is used in an amount of 40 to 10 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber having an acrylonitrile bond amount of 10 to 30%.
It is a hydrogenated nitrile rubber composition in which 0 parts by weight and more preferably 50 to 80 parts by weight are blended.

The hydrogenated nitrile rubber used in the present invention comprises 10 to 55% by weight of acrylonitrile, methacrylonitrile and other unsaturated nitriles and 1,3-butadiene, 2,3-dimethylbutadiene, isoprene, 1,3
Pentadiene, 90 to 45% by weight of other conjugated dienes
And a multi-component copolymer obtained by copolymerizing a copolymerizable ethylenically unsaturated monomer in addition to these monomers. If the amount of unsaturated nitrile in the nitrile rubber is too small, the oil resistance is low, and
Conversely, if it is excessive, general physical properties such as hardness and modulus are inferior. Examples of the ethylenically unsaturated monomer include vinyl aromatic compounds such as styrene, chloromethylstyrene, α-methylstyrene, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, ethoxyethyl acrylate, maleic acid, and itacone. Examples include unsaturated dicarboxylic acids such as acid, monomethyl maleate and dimethyl maleate, and monoesters and diesters of these unsaturated dicarboxylic acids.

An acrylonitrile having an amount of 10 to 30% and having excellent cold resistance which maintains flexibility even at a low temperature is used. Acrylonitrile binding amount is 10%
If it is less than 30%, the hardness, modulus, and oil resistance decrease, and the function as a power transmission belt cannot be satisfied. If it exceeds 30%, the cold resistance decreases and the life of the belt in a low-temperature environment is shortened. .

The plasticizer is used for imparting flexibility in a low-temperature environment and preventing bending fatigue at low temperatures. Examples of the plasticizer used in the present invention include polydimethylsiloxane oil, diphenylsilanediol, trimethylsilanol, and other DOP.
Phthalate, DOA, DIDA, etc., adipate, DOS, DBS, etc., sebacate, TOP, T
Examples include phosphate-based and polyether-based plasticizers such as BP. And the compounding amount of the plasticizer is 10
50 parts by weight, preferably 20 to 40 parts by weight. If the amount is less than 10 parts by weight, the cold resistance is not sufficiently improved, and if the amount exceeds 50 parts by weight, a problem such as bleeding of the plasticizer occurs, which is not preferable.

Carbon black is blended to suppress the bleeding of the plasticizer and to maintain physical properties such as hardness and modulus of the belt at a high level. The blending amount is 40 to 100 parts by weight, preferably 50 to 80 parts by weight. Parts. If the amount of the carbon black is less than 40 parts by weight, bleeding of the plasticizer becomes apparent, and physical properties such as hardness and modulus are reduced, so that the function as a power transmission belt cannot be satisfied. On the other hand, if it exceeds 100 parts by weight, the hardness becomes too high, the elongation becomes low, and the cold resistance life becomes short, which is not preferable.

In the present invention, the blending amount of the plasticizer and carbon black is from 10:40 to 50: 100. Carbon black is blended with a plasticizer to prevent the plasticizer from bleeding or deteriorating its physical properties. It is necessary to mix in.

The hydrogenated nitrile rubber composition of the present invention comprises
In addition to the above-mentioned plasticizer and carbon black, various additives are blended as required. For example, short fibers, cross-linking agents, anti-aging agents, heat-resistant agents, tackifiers, anti-scorch agents, cross-linking accelerators, accelerating aids, cross-linking retarders, coloring agents, ultraviolet absorbers, flame retardants, oil resistance improvers, And other fillers.

As the short fiber, a commonly used short fiber having a length of about 1 to 10 mm made of fibers such as cotton, polyester, polyamide and aramid can be used.
In addition, a special size ultrashort fiber having a diameter of 0.1 to 2.0 μm and a length of 10 μm to 1.0 m can be used as the short fiber. A higher level of homogeneity over the entire stretch belt can be achieved. As a mixture obtained by mixing short fibers having such a diameter and length into a hydrogenated nitrile rubber and uniformly dispersing the same, for example, Super Hybrid Pol (trade name, manufactured by Ube Industries, Ltd.)
ymer.

In the case of such ultra-short fibers, the dispersibility of the short fibers and the homogeneity of the hydrogenated nitrile rubber can be raised to a high level, and the generation and deterioration of cracks due to the blending of the short fibers can be suppressed. it can. In view of such a high level of dispersibility and homogeneity, if the diameter of the short fiber is less than 0.1 μm, the dispersion state becomes non-uniform, and if the diameter is more than 2.0 μm, the homogeneity is impaired, and the belt runs. The possibility that a short fiber portion becomes a starting point to cause a crack increases.

When the length of the short fibers is less than 10 μm, the effect of improving the modulus of the hydrogenated nitrile rubber is reduced. If the length is longer than 0 mm, the dispersion state in the hydrogenated nitrile rubber becomes uneven, and the elasticity of the conveying belt becomes uneven as a whole.

On the other hand, the amount of short fibers mixed into the hydrogenated nitrile rubber is 1 to 100 parts by weight of the hydrogenated nitrile rubber.
It is preferable to mix in a range of 30 parts by weight. If the amount is less than 1 part by weight, the effect of improving the modulus of short fibers cannot be sufficiently obtained, and if it exceeds 20 parts by weight, the hardness becomes too high, which is not preferable.

The crosslinking agent is sulfur or an organic peroxide, and the organic peroxide is based on 100 parts by weight of the hydrogenated nitrile rubber.
0.2 to 6 parts by weight, preferably 0.3 to 4 parts by weight is blended. If the amount is less than 0.2 parts by weight, crosslinking becomes insufficient,
Physical properties such as tensile strength are inferior. Conversely, if it exceeds 6 parts by weight, overcrosslinking occurs, resulting in rubber with poor elongation, which is not preferable.

Specifically, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
2,2-bis (t-butylperoxy) -p-diisopropylbenzene, dicumyl peroxide, di-t-butyl peroxide, t-butyl perbenzoate,
1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dicumyl peroxide , Dicumyl peroxide, dialkyl peroxide, and ketal peroxide. Examples of the crosslinking accelerator include stearic acid and zinc oxide.

Examples of the antioxidants include phenylenediamines, phosphates, quinolines, cresols, phenols, and dithiocarbamate metal salts.

As the heat-resistant agent, iron oxide, cesium oxide,
Examples thereof include potassium hydroxide, iron naphthenate, and potassium naphthenate.

As the filler, diatomaceous earth, zinc white, basic magnesium carbonate, calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, mica,
Examples include inorganic fillers such as aluminum sulfate, calcium sulfate, barium sulfate, asbestos, glass fiber, carbon black, calcium carbonate, titanium dioxide, clay, talc, alumina, and silica.

Further, a metal salt of an unsaturated carboxylic acid can be blended as a reinforcing agent. Examples of unsaturated carboxylic acids include monocarboxylic acids such as acrylic acid and methacrylic acid, dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, monomethyl maleate, and monomethyl itaconate. The metal may be any as long as it forms a salt with an unsaturated carboxylic acid, but usually beryllium, magnesium, calcium, strontium, barium, titanium, chromium, molybdenum, manganese, iron, cobalt, nickel, copper, Silver, zinc, cadmium, aluminum,
Tin, lead, mercury, antimony, and the like can be used, but zinc, magnesium, calcium, and aluminum are often used when reinforcing rubber.

The belts to which the present invention can be applied include those used for power transmission and those used for conveyance.
It is not limited to use or shape / specifications,
, A flat belt as shown in FIG. 2,
The present invention can be applied to various belts such as a V-belt as shown in FIG. 3 and a V-ribbed belt, a wrapped belt and a conveyor belt (not shown). Further, the whole belt is not made of this rubber composition, and if only the compressed rubber part is used, only the back rubber or a part of the belt made of this rubber composition is included in the scope of the invention. It is included in. Next, the effects of the present invention were confirmed with reference to examples of the present invention and comparative examples.

[0035]

Example 1 In Example 1, 45 parts by weight of carbon black and 10 parts by weight of a plasticizer were used as hydrogenated nitrile rubber per 100 parts by weight of Zetpol 4110 (acrylonitrile amount: 16.7%) manufactured by Zeon Corporation. In addition, rubber properties such as hardness and modulus were measured using a rubber composition having the composition shown in Table 1 and a low temperature (Gehman) torsion test was performed. In addition, a toothed belt was prepared using a glass rope as a core wire and a rubber composition having the composition shown in Table 1, and the size of the driving pulley was 2000 rpm at 24 T, the size of the driven pulley was 24 T, and the atmosphere was The belt was run at a temperature of -40C.
The bleed of the plasticizer from the belt surface was visually evaluated. Table 2 shows the results.

Example 2 A rubber compounded under exactly the same conditions as in Example 1 except that the compounding amount of carbon black was 50 parts by weight and the compounding amount of the plasticizer was 15 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. The physical properties of the composition were measured, and a toothed belt was prepared and run. Table 2 shows the results.

Example 3 Rubber compounded under exactly the same conditions as in Example 1 except that the compounding amount of carbon black and the compounding amount of the plasticizer were 25 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. The physical properties of the composition were measured, and a toothed belt was prepared and run. Table 2 shows the results.

Example 4 A rubber compounded under exactly the same conditions as in Example 1 except that the compounding amount of carbon black was 80 parts by weight and the compounding amount of the plasticizer was 40 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. The physical properties of the composition were measured, and a toothed belt was prepared and run. Table 2 shows the results.

Example 5 Example 1 was repeated except that the amount of carbon black was 100 parts by weight and the amount of plasticizer was 50 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber.
Physical properties were measured with a rubber composition compounded under exactly the same conditions as in Example 1, and a toothed belt was prepared and run. Table 2 shows the results.

(Comparative Example 1) Zetpol 2020 (acrylonitrile amount: 36.2%) from Zeon Corporation was used as the hydrogenated nitrile rubber, and the blending amount of carbon black with respect to 100 parts by weight of the hydrogenated nitrile rubber was 40 parts by weight, and the plasticizer was used. Was measured under the same conditions as in Example 1 except that the blending amount of the rubber composition was changed to 5 parts by weight, and a toothed belt was prepared and run. Table 2 shows the results.

Comparative Example 2 A rubber compounded under exactly the same conditions as in Example 1 except that the compounding amount of carbon black was 40 parts by weight and the compounding amount of the plasticizer was 5 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. The physical properties of the composition were measured, and a toothed belt was prepared and run. Table 2 shows the results.

Comparative Example 3 A rubber compounded under exactly the same conditions as in Example 1 except that the compounding amount of carbon black and the compounding amount of the plasticizer were 30 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. The physical properties of the composition were measured, and a toothed belt was prepared and run. Table 2 shows the results.

Comparative Example 4 Example 1 was repeated except that the compounding amount of carbon black was changed to 120 parts by weight and the compounding amount of the plasticizer was changed to 65 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber.
Physical properties were measured with a rubber composition compounded under exactly the same conditions as in Example 1, and a toothed belt was prepared and run. Table 2 shows the results.

[0044]

[Table 1]

[0045]

[Table 2]

As shown in Table 2, in Comparative Example 1, a hydrogenated nitrile rubber having an acrylonitrile bond amount of 36.2% was used, and a hydrogenated nitrile rubber having an acrylonitrile bond amount of 16.7% was used. Compared to Comparative Example 2 and the present invention, the results of the low-temperature torsion test are inferior, and the life is short even in the running test in a low-temperature environment.

In Comparative Example 2, a hydrogenated nitrile rubber having an acrylonitrile bond amount of 16.7% was used. However, if the amount of the plasticizer was small, the physical properties at low temperature were not sufficiently improved, and the life in a running test was poor. Similarly not enough. In Comparative Example 3, the ratio of the plasticizer to the carbon black was 30:40, which was out of the range of the present invention. Therefore, good results were not obtained in the bleeding evaluation of the plasticizer.

In Comparative Example 4, both the plasticizer and the carbon black were added in excess of the scope of the present invention, but the hardness and modulus were too high, and it was found that the plasticizer and carbon black deteriorated earlier and did not have a long life. .

[0049]

As described above, in claim 1 of the present invention, 10 to 50 parts by weight of a plasticizer is added to 100 parts by weight of a hydrogenated nitrile rubber having an acrylonitrile bond amount of 10 to 30%.
Contains 40 to 100 parts by weight of carbon black,
The weight ratio of the plasticizer to carbon black is 10:40 to 5
It is characterized by comprising a hydrogenated nitrile rubber composition in the range of 0: 100.

Thus, the acrylonitrile bond amount of 10
The hydrogenated nitrile rubber of 30% to 30% has improved cold resistance, and the amount of the plasticizer is set to 10 to 50 parts by weight, which is larger than the usual amount, so that it is sufficiently flexible even at extremely low temperatures. It is possible to obtain a belt having a property and having little deterioration even if it is bent and stretched rapidly. And
40 to 40 times more carbon black than usual
By blending 100 parts by weight, it is possible to prevent bleeding of the plasticizer blended in a large amount as described above, and to provide a material which can withstand use as a belt without deteriorating physical properties such as hardness and modulus of the belt. can do.

In claim 2, the hydrogenated nitrile rubber 100
The transmission belt has a blending amount of the plasticizer of 20 to 40 parts by weight with respect to part by weight. 20 to 40 plasticizer
By setting the amount by weight, the effect of improving the cold resistance by the plasticizer is obtained, and the blending amount is too large, and the bleeding of the plasticizer, and the physical properties such as hardness and modulus are not reduced, so that the range is more appropriate. It can be said.

In claim 3, the hydrogenated nitrile rubber 100
50 to 80 parts by weight of carbon black based on parts by weight
The transmission belt is a weight part. By setting the blending amount of carbon black to 50 to 80 parts by weight, the problem of bleeding of the plasticizer can be sufficiently suppressed, and the belt becomes too hard due to excessive blending of carbon black, and conversely, cracks may occur. No problem.

In the fourth aspect, the acrylonitrile bond amount is 1
10 to 50 parts by weight of a plasticizer and 40 to 40 parts by weight of carbon black with respect to 100 parts by weight of a hydrogenated nitrile rubber of 0 to 30%.
A hydrogenated nitrile rubber composition for a power transmission belt comprising 100 parts by weight of a hydrogenated nitrile rubber composition in which a weight ratio of a plasticizer and carbon black is in a range of 10:40 to 50: 100. Things.

As in the first aspect, the hydrogenated nitrile rubber having an acrylonitrile bond content of 10 to 30% has improved cold resistance, and the compounding amount of the plasticizer is larger than that of the normal compounding amount by 10 to 50%. By using parts by weight, it is possible to obtain a belt having sufficient flexibility even at extremely low temperatures and having little deterioration even if it is rapidly bent and stretched. By blending 40 to 100 parts by weight of carbon black, which is also larger than the usual blending amount, bleeding of the plasticizer blended in a large amount as described above can be prevented, and physical properties such as hardness and modulus of the belt also decrease. A belt that can be used as a belt without causing the belt to be used can be provided.

According to a fifth aspect of the present invention, there is provided a hydrogenated nitrile rubber composition for a power transmission belt in which a blending amount of a plasticizer is 20 to 40 parts by weight with respect to 100 parts by weight of the hydrogenated nitrile rubber. By setting the blending amount of the plasticizer to 20 to 40 parts by weight,
It can be said that the effect of improving the cold resistance by the plasticizer is obtained, and that the blending amount is too large and the bleeding of the plasticizer and the decrease in physical properties such as hardness and modulus are within a more appropriate range.

According to a sixth aspect of the present invention, there is provided a hydrogenated nitrile rubber composition for a power transmission belt in which the blending amount of carbon black is 50 to 80 parts by weight with respect to 100 parts by weight of the hydrogenated nitrile rubber. By setting the blending amount of carbon black to 50 to 80 parts by weight, the problem of bleeding of the plasticizer can be sufficiently suppressed, and the belt becomes too hard due to excessive blending of carbon black, and conversely, cracks may occur. No problem.

[Brief description of the drawings]

FIG. 1 is a sectional perspective view of a main part of a toothed belt to which the present invention is applied.

FIG. 2 is a sectional perspective view of a main part of a flat belt to which the present invention is applied.

FIG. 3 is a cross-sectional perspective view of a main part of a V-belt to which the present invention is applied.

[Explanation of symbols]

 Reference Signs List 1 belt 2 rubber material 3 core wire 4 canvas layer 5 adhesive rubber layer

Claims (6)

[Claims] An acrylonitrile bond amount of 10 to 30%
Plasticizer per 100 parts by weight of hydrogenated nitrile rubber
0 to 50 parts by weight, and 40 to 100 parts by weight of carbon black, wherein the weight ratio of the plasticizer to carbon black is in the range of 10:40 to 50: 100. Power transmission belt characterized by: 2. The power transmission belt according to claim 1, wherein the amount of the plasticizer is 20 to 40 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. 3. The power transmission belt according to claim 1, wherein the compounding amount of carbon black is 50 to 80 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. 4. An acrylonitrile bond amount of 10 to 30%
Plasticizer per 100 parts by weight of hydrogenated nitrile rubber
0 to 50 parts by weight, and 40 to 100 parts by weight of carbon black, wherein the weight ratio of the plasticizer to carbon black is in the range of 10:40 to 50: 100. A hydrogenated nitrile rubber composition for a power transmission belt. 5. The hydrogenated nitrile rubber composition for a power transmission belt according to claim 4, wherein the blending amount of the plasticizer is 20 to 40 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber. 6. The hydrogenated nitrile rubber composition for a power transmission belt according to claim 4, wherein the compounding amount of carbon black is 50 to 80 parts by weight based on 100 parts by weight of the hydrogenated nitrile rubber.