WO2003057775A1

WO2003057775A1 - Vulcanizable rubber composition and vulcanizate

Info

Publication number: WO2003057775A1
Application number: PCT/JP2002/013764
Authority: WO
Inventors: Akira Tsukada; Shigeru Fujita
Original assignee: Zeon Corporation
Priority date: 2001-12-28
Filing date: 2002-12-27
Publication date: 2003-07-17
Also published as: JP2003192834A

Abstract

A vulcanizable rubber composition which comprises: 100 parts by weight of a rubber ingredient comprising (A) 5 to 50 parts by weight of a nitrile copolymer rubber having a content of α,ß-ethylenically unsaturated nitrile monomer units of 10 to 60 wt.% and having an iodine value of 180 to 430 and (B) 50 to 95 parts by weight of a nitrile copolymer rubber having a content of α,ß-ethylenically unsaturated nitrile monomer units of 10 to 60 wt.% and having an iodine value of 40 to 100; and 0.1 to 1.5 parts by weight of at least one vulcanizing agent selected between sulfur and 4,4'-dithiodimorpholine, in terms of sulfur amount. The vulcanizable rubber composition gives a vulcanizate excellent in dynamic properties and heat resistance and reduced in compression set.

Description

Description Vulcanizable rubber composition and vulcanizate

The present invention relates to a vulcanizate of a nitrile group-containing copolymer rubber excellent in dynamic characteristics and heat resistance and having a small compression set, and a vulcanizable rubber composition as a material thereof. Background art

It is generally known that nitrile group-containing copolymer rubber such as acrylonitrile-butadiene copolymer rubber has excellent oil resistance. Further, hydrogenated acrylonitrile-butadiene copolymer rubber obtained by hydrogenating acrylonitrile-butadiene copolymer rubber for the purpose of improving heat resistance, chemical resistance, weather resistance, tensile strength and the like is known. However, the hydrogenated acrylonitrile-butadiene copolymer rubber has a problem that the compression set is larger than that of the acrylonitrile-butadiene copolymer rubber before hydrogenation.

Therefore, it has been proposed to blend acrylonitrile-butadiene copolymer rubber and hydrogenated acrylonitrile-butadiene copolymer rubber and vulcanize the blend with sulfur (Japanese Patent Application Laid-Open No. 63-142020). 4 No. 6). However, in this proposed technology, since the hydrogenated acrylonitrile-butadiene copolymer rubber having an iodine value of 30 or less is used, the amount of unsaturated bonds between the two types of rubber is significantly different. In addition, the vulcanization rates differ greatly, making co-vulcanization difficult.To solve this, vulcanization is carried out using a large amount of sulfur, 2 to 10 parts by weight per 100 parts by weight of the rubber component. You. However, the vulcanizates obtained in this way have a problem that, due to the large amount of sulfur, hardness tends to increase due to heat aging, elongation tends to decrease, and compression set also increases. I have.

On the other hand, a vulcanized rubber obtained by vulcanizing these two types of blend rubber with an organic peroxide instead of sulfur has also been proposed (Japanese Patent Application Laid-Open No. 9-647471). However, this vulcanized rubber had a problem of having a bad odor. Disclosure of the invention

An object of the present invention is to provide a nitrile group-containing copolymer rubber vulcanized with sulfur, which has excellent dynamic characteristics and heat resistance, and has a small compression elongation, in view of the above prior art, and a material thereof. It is to provide a vulcanizable rubber composition.

The present inventors have conducted intensive studies to achieve the above object, and as a result, when two types of nitrile group-containing copolymer rubbers having an iodine value in a specific range are used in combination, even if a small amount of sulfur is used, a strong copolymer is formed between the two. The present inventors have found that vulcanization occurs, and have completed the present invention based on this finding.

Thus, according to the present invention, (ii) a copolymer containing a nitrile group having a 3-ethylenically unsaturated nitrile monomer unit content of from 10 to 60% by weight and an iodine value of from 180 to 430. Rubber

(A) 5 to 50 parts by weight and a nitrile group-containing copolymer rubber having an α,) 3-ethylenically unsaturated nitrile monomer unit content of 10 to 60% by weight and an iodine value of 40 to 100 (Ii) 100 to 100 parts by weight of a rubber component consisting of 50 to 95 parts by weight, and at least one vulcanizing agent selected from sulfur and 4,4'-dithiodimorpholine in terms of sulfur content of 0.1. There is provided a vulcanizable rubber composition containing up to 1.5 parts by weight.

Further, according to the present invention, the vulcanizable rubber composition containing the nitrile group-containing copolymer rubber (Α), the nitrile group-containing copolymer rubber (Β) and a sulfur-based vulcanizing agent is vulcanized. A vulcanizate is provided. BEST MODE FOR CARRYING OUT THE INVENTION

The vulcanizable rubber composition of the present invention comprises a rubber component 1 comprising 5 to 50% by weight of a nitrile group-containing copolymer rubber (Α) and 50 to 95% by weight of a nitrile group-containing copolymer rubber (Β). It contains 0.1 parts by weight and 0.1 to 1.5 parts by weight of sulfur in terms of sulfur and at least one selected from 4,4'-dithiodimorpholine as a vulcanizing agent.

The nitrile group-containing copolymer rubber (Α), which accounts for 5 to 50 parts by weight of 100 parts by weight of the rubber component contained in the vulcanizable rubber composition of the present invention, is α,) 3_ethylenically unsaturated A rubber obtained by copolymerizing a nitrile monomer with other monomers. It has an unsaturated nitrile monomer unit content of 10 to 60% by weight and an iodine value of 180 to 430.

Examples of the α, / 3-ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, and acrylonitrile monochloride, with acrylonitrile being preferred. The content of the α,) 3-ethylenically unsaturated nitrile monomer unit in the nitrile group-containing copolymer rubber (Α) is 10 to 60% by weight, preferably 12 to 55% by weight, Preferably it is 15 to 50% by weight. If the content of α, / 3_ethylenically unsaturated nitrile monomer is too low, the oil resistance of the vulcanizate is poor, and if it is too high, the cold resistance is poor.

In the nitrile group-containing copolymer rubber (Α), the monomers to be copolymerized with the α, J3-ethylenically unsaturated nitrile monomer include a conjugated diene monomer, a non-conjugated diene monomer and For example, freerefin is exemplified. These monomers can be copolymerized alone or in combination of two or more. Of these monomers, conjugated diene monomers are preferred. Examples of the conjugated diene monomer include 1,3-butane gen, isoprene, 2,3-dimethyl-1,3-butadiene and 1,3-pentene gen. Butadiene and isoprene are preferred, and 1,3-butane is particularly preferred. The non-conjugated diene monomer preferably has 5 to 12 carbon atoms, and examples thereof include 1,4-pentene, 1,4-hexadiene, vinylnorbornene, and dicyclopentene. As the α-olefin, those having 2 to 12 carbon atoms are preferable, and examples thereof include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 11-hexene, and 1-octene. In the nitrile group-containing copolymer rubber (Α), the amount of the unit of the monomer copolymerized with the ， / 3-ethylenically unsaturated nitrile monomer is 40 to 90% by weight, It is preferably from 45 to 88% by weight, more preferably from 50 to 85% by weight.

Further, in addition to the above monomers, an aromatic vinyl monomer, a fluorine-containing vinyl monomer, [3] -ethylenically unsaturated monocarboxylic acid, [3], i3-ethylenically unsaturated polycarboxylic acid Alternatively, an anhydride thereof, a copolymerizable antioxidant, or the like may be copolymerized.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyl pyridine and the like. Examples of fluorine-containing vinyl monomers include, for example, full Examples include fluoroethyl vinyl ether, fluoropropyl vinyl ether, o-trifluoromethylstyrene, penfluorovinyl benzoate, difluoroethylene, tetrafluoroethylene and the like. Examples of the a, i3-ethylenically unsaturated monocarboxylic acid include acrylic acid and methyl methacrylate. Examples of the α, β-ethylenically unsaturated polycarboxylic acid include itaconic acid, fumaric acid, and maleic acid. Examples of the / 3-ethylenically unsaturated polycarboxylic anhydride include itaconic anhydride and maleic anhydride. Examples of copolymerizable antioxidants include Ν— (4-anilinophenyl) acrylamide, Ν- (4-anilinophenyl) methacrylamide, Ν— (4-anilinophenyl) cinnamamide, Ν— (4-anilinophenyl) crotonamide , Ν-phenyl-4- (3-vinylbenzyloxy) aniline, Ν-phenyl-4_ (4-vinylpentyloxy) aniline and the like.

The iodine value of the nitrile group-containing copolymer rubber (Α) is from 180 to 430, preferably from 200 to 400, more preferably from 230 to 380. If the iodine value is too small, the vulcanizate will have poor rubber elasticity. Conversely, if the iodine value is too large, the vulcanizate will have poor oil resistance and heat resistance, and it will be difficult to covulcanize with the nitrile group-containing copolymer rubber (II). The iodine value is a value indicating the amount of unsaturated bonds in the main chain, and is determined mainly by the content of conjugated gen monomer units. If necessary, the iodine value may be adjusted by hydrogenating the nitrile group-containing copolymer rubber (II) to saturate unsaturated bonds by a known method.

The nitrile group-containing copolymer rubber (Α) preferably has a viscosity (ML _{1 + 4} , 100) of 20 to 300, more preferably 30 to 250, and particularly preferably 30 to 250. 40 to 200. If the Mooney viscosity is too low, the mechanical properties of the vulcanizate may be poor, and if too high, the workability may be poor.

The nitrile group-containing copolymer rubber (B), which accounts for 50 to 95 parts by weight in 100 parts by weight of the rubber component contained in the vulcanizable rubber composition of the present invention, is a nitrile group-containing copolymer rubber. Similar to (A), it is a rubber obtained by copolymerizing a /, 3-ethylenically unsaturated nitrile monomer with another monomer. Unit content 1 0 ~ 60% by weight. The nitrile group-containing copolymer rubber (B) has an iodine value of 40 to 100.

The α,] 3-ethylenically unsaturated nitrile monomer content of the nitrile group-containing copolymer rubber (B) is from 10 to 60% by weight, preferably from 12 to 55% by weight, more preferably It is 15 to 50% by weight. If the content of α,] 3-ethylenically unsaturated nitrile monomer is too small, the vulcanizate has poor oil resistance, while if it is too large, the vulcanizate has poor cold resistance.

The iodine value of the nitrile group-containing copolymer rubber (Β) is from 40 to 100, preferably from 45 to 90, more preferably from 50 to 80. If the iodine value is too small, the compression set of the vulcanizate will increase, and it will be difficult to vulcanize with the nitrile group-containing copolymer rubber (II). Conversely, if the iodine value is too large, heat resistance is poor. When the nitrile group-containing copolymer rubber contains a large amount of conjugated diene monomer units, and therefore has a large number of unsaturated bonds in the main chain and a high iodine value, hydrogenation is carried out by a known method to obtain an unsatisfactory main chain. The iodine value may be adjusted to a small value by reducing the number of saturated bonds.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the nitrile group-containing copolymer rubber (Β) is preferably from 10 to 300, more preferably from 20 to 250, and particularly preferably. Is from 30 to 200. If the viscosity is too low, the mechanical properties of the vulcanizate may be poor, and if too high, the workability may be poor.

The relative proportions of the nitrile group-containing copolymer rubber (A) and the nitrile group-containing copolymer rubber (B) in the rubber component contained in the vulcanizable rubber composition of the present invention are as follows. 5 to 50 parts by weight, preferably 10 to 45 parts by weight, more preferably 20 to 40 parts by weight, and more preferably 20 to 40 parts by weight of nitrile group-containing copolymer rubber, based on 100 parts by weight. The amount of the copolymer rubber (B) is from 95 to 50 parts by weight, preferably from 90 to 55 parts by weight, and more preferably from 80 to 60 parts by weight. If the relative proportion of the nitrile group-containing copolymer rubber (A) is too small, the vulcanizate has a large compression set. Conversely, if it is too large, the vulcanizate is still poor in constant elongation fatigue.

The rubber component may additionally contain a rubber other than the nitrile group-containing copolymer rubber (A) and the nitrile group-containing copolymer rubber (B), but the amount of the rubber component is 100% by weight. The amount is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, particularly preferably 10 parts by weight or less. The vulcanizable rubber composition of the present invention contains, as a vulcanizing agent, at least one selected from sulfur and 4,4′-dithiodimorpholine. As the sulfur, powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur and the like are usually used. The content of the vulcanizing agent is 0.1 to 1.5 parts by weight, preferably 0.2 to 1 part by weight, more preferably 0.3 to 1.3 parts by weight based on 100 parts by weight of the rubber component. ~ 0.8 parts by weight. If the amount of the vulcanizing agent is too small, sufficient vulcanization will not be performed and the strength of the vulcanized product will be insufficient. And the elongation is greatly reduced, resulting in poor heat resistance. Also, the permanent set is large.

The sulfur and Z or 4,4'-dithiodimorpholine vulcanizing agent used in the present invention is usually used in combination with a vulcanization accelerator. Conventionally, vulcanization accelerators include zinc white, sulfenamide-based vulcanization accelerator, guanidine-based vulcanization accelerator, thiazol-based vulcanization accelerator, and thiuram, which are used in combination with sulfur or sulfur-containing vulcanization agents. Vulcanization accelerators and dithioate vulcanization accelerators. The amount of the vulcanization accelerator used is not particularly limited, and may be determined according to the use of the vulcanized product, the required performance, the type of the vulcanization accelerator, and the like.

The vulcanizable rubber composition of the present invention includes a compounding agent used for general rubber, for example, a reinforcing agent such as carbon black, silica, and short fiber; a calcium carbonate, a clay, a silver salt, a calcium gayate, and the like. Fillers; metal salts of ethylenically unsaturated carboxylic acids; plasticizers; pigments; antioxidants; tackifiers; processing aids; anti-scorch agents;

The method for preparing the vulcanizable rubber composition of the present invention is not particularly limited, and may be prepared by a general method for preparing a vulcanizable rubber composition. May be kneaded. However, after blending the vulcanizing agent and the vulcanization accelerator, the blended composition is kneaded while maintaining the temperature below the vulcanization starting temperature.

The vulcanizate of the present invention is obtained by vulcanizing the above vulcanizable rubber composition. The method for vulcanizing the rubber composition may include heating the vulcanizable rubber composition. Generally, heating is performed after molding, or heating is performed simultaneously with molding.

The temperature at the time of vulcanization is preferably from 100 to 200, more preferably from 130 to 19 ° 5 ° C, and particularly preferably from 140 to 190. If the temperature is too low, the vulcanization time may be long and the vulcanization density may be low. Temperature is too high In this case, molding may be defective. The vulcanization time varies depending on the vulcanization method, vulcanization temperature, shape, etc., but is preferably 1 minute to 4 hours in terms of vulcanization density and production efficiency.

The heating method for vulcanization may be appropriately selected from the methods used for vulcanization of rubber, such as press heating, steam heating, oven heating, and hot air heating.

Depending on the shape and size of the vulcanized product, the surface may be vulcanized but the inside may not be vulcanized. In such a case, after vulcanization as described above, secondary vulcanization for maintaining a high temperature state may be performed.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In these examples, parts and percentages are by weight unless otherwise indicated.

The properties of the rubber vulcanizate were evaluated by the following methods.

Normal physical properties

The prepared vulcanizable rubber composition was vulcanized at 160 at a press pressure of 1 OMPa for 20 minutes to obtain a sheet having a thickness of 2 mm. This sheet was punched out to produce a test piece. Using these test specimens, the tensile strength and elongation of the vulcanizate were measured in accordance with Japanese Industrial Standard JISK 6251, and the vulcanizate was measured using a Durometer overnight hardness tester type に従い in accordance with JIS Κ 6253. The hardness was measured.

Heat-resistant

After measuring the above normal physical properties, the specimen was kept at 120, and after 168 hours and 336 hours, the tensile strength (MPa), elongation (%) and hardness of the vulcanized product were measured, respectively. The rate of change (%) of those measured values before holding at a high temperature was examined. The larger the change, the lower the heat resistance.

Dynamic characteristics

After vulcanizing a cylindrical test specimen with a diameter of 17.8 ± 0.1 mm and a height of 25 ± 0.15 mm at 160 ° C for 20 minutes, a flexometer test specified in ASTM D 623-78 was applied. evaluated. The test was performed using a Goodrich Flexometer at a test temperature of 100 ° C, an initial load of 25 pounds (11.34 kg), a dynamic displacement of 4.45 mm, and a dynamic displacement of 25 minutes, with the HBU applied. (Calorific value [in]: measured The difference between the temperature of the test piece and the ambient temperature of 1 oot: was defined as the exothermic temperature) and PS (permanent strain) (%) were measured. The smaller the HBU and PS, the better the dynamic characteristics. Constant elongation fatigue

The prepared vulcanizable rubber composition was vulcanized at 16 O for 20 minutes under a pressure of 1 OMPa to obtain a sheet having a thickness of 2 mm. This sheet was punched out using a No. 3 dumbbell to prepare a test piece. Using these test pieces, fix both ends with a gripper so that the distance between them is 75 mm, and repeat reciprocating motion at 23 ° C 300 times per minute so that the test pieces can be extended 0 to 100%. And the number of times the test piece was broken was measured.

Compression set

Using a mold having a diameter of 29 mm and a thickness of 12.5 mm, the vulcanizable rubber composition was vulcanized at 160 at a press pressure of 10 MPa for 25 minutes to obtain a test piece. The compression set (%) was measured in accordance with JIS K 6262 using these test specimens after maintaining them in a 25% compressed state at 120 ° C. for 70 hours and after maintaining them for 168 hours.

Example 1

Nitrile group-containing copolymer rubber A-1 (Nipo 1 DN 1042AL, manufactured by Nippon Zeon Co., Ltd., acrylonitrile-butadiene copolymer rubber, acrylonitrile unit content 33.5%, iodine value about 313, ML _{1 + 4} , (100) 46) 40 parts, nitrile group-containing copolymer rubber B (Z etpol 2030L, manufactured by Zeon Corporation, hydrogenated acrylonitrile-butadiene copolymer rubber, acrylonitrile unit content 36.2 %, Iodine value approx. 56, mu-viscosity ML _{1 + 4} , (100) 57.5) 60 parts, carbon black (N762, Asahi # 50, Asahi Rikibon Co., Ltd.) 65 parts, stearic acid 1 part , Zinc oxide 5 parts, tree (2-ethylhexyl) trimellitate (plasticizer) 8 parts, 2,2,4-trimethyl-1,2-dihydroquinoline polymer

(Anti-aging agent, No crac 224, manufactured by Ouchi Shinko Co., Ltd.) 1.5 parts, N-isopropyl-1-N'-phenyl-p-phenylenediamine (anti-aging agent) 1.5 parts, Pex Light S (manufactured by Seiko Kagaku Co., Ltd.) 1 part, powdered sulfur (pass through 325 mesh) 0.8 part, vulcanization accelerator (1.5 parts tetramethylthiuram disulphide) and N-cyclohexyl-2-benzothia 1.5 parts of jilsulfenamide) 3 parts, 50t: And kneaded in a roll to prepare a vulcanizable rubber composition. Using this vulcanizable rubber composition, vulcanization was performed to produce each test piece, and heat resistance, dynamic characteristics, constant elongation fatigue resistance, and permanent compression strain were evaluated. Table 1 shows the results.

Example 2

The same treatment as in Example 1 was conducted except that the amount of the nitrile group-containing copolymer rubber A-1 was changed from 40 parts to 20 parts and the amount of the nitrile group-containing copolymer rubber B was changed from 60 parts to 80 parts. Table 1 shows the results.

Example 3

Instead of nitrile group-containing copolymer rubber A-1, nitrile group-containing copolymer rubber A-2 (Nipol D 1201 L, manufactured by Zeon Corporation, acrylonitrile-butene-isoprene copolymer rubber, acrylonitrile The treatment was carried out in the same manner as in Example 1 except that a unit content of 35%, an iodine value of about 280, and a muny viscosity ML _{1 + 4} ( ₁₀₀ :) 46) were used. Table 1 shows the results.

Example 4

The procedure was as in Example 1, except that the amount of sulfur was changed to 1.3 parts. The results are shown in Table 1.

Example 5

The same procedure as in Example 1 was carried out except that instead of 0.8 parts of powdered sulfur, 3 parts of 4,4′-dithiodimorpholine (equivalent to 0.91 part of sulfur) was used. Table 1 shows the results. Comparative Example 1

The same treatment as in Example 1 was carried out except that the nitrile group-containing copolymer rubber A-1 was not used and the amount of the nitrile group-containing copolymer rubber B was changed from 60 parts to 100 parts. The results are shown in Table 1.

Comparative Example 2

The processing was performed in the same manner as in Example 1 except that the amount of the nitrile group-containing copolymer rubber A-1 was changed from 40 parts to 100 parts, and the nitrile group-containing copolymer rubber B was not used. Table 1 shows the results.

Comparative Example 3 The same treatment as in Example 1 was carried out except that the amount of the nitrile group-containing copolymer rubber A-1 was changed from 40 parts to 70 parts and the amount of the nitrile group-containing copolymer rubber B was changed from 60 parts to 30 parts. Table 1 shows the results.

Comparative Example 4

Instead of nitrile group-containing copolymer rubber B, nitrile group-containing copolymer rubber b (Ze tpo 1 2020, manufactured by Zeon Corporation, hydrogenated acrylonitrile-butadiene copolymer rubber, acrylonitrile unit content 36.2%, iodine value The same treatment as in Example 1 was carried out except that about 28, Mooney viscosity ML _{1 + 4} , (100 ° C) 78) was used. Table 1 shows the results.

Comparative Example 5

The procedure was as in Example 1, except that the amount of sulfur powder was changed from 0.8 parts to 2.5 parts. Table 1 shows the results.

As shown in Table 1, the vulcanizate of the rubber composition containing no nitrile group-containing copolymer rubber (A) having a high iodine value (Comparative Example 1) has a large compression set and a constant elongation fatigue test. The number of breaks at is small. The vulcanizate of the rubber composition containing no nitrile group-containing copolymer rubber (B) having a low iodine value (Comparative Example 2) has a small number of breaks in the constant elongation fatigue test. The vulcanizate of a rubber composition containing a large amount of nitrile group-containing copolymer rubber having a large iodine value (A) and a small amount of a nitrile group-containing copolymer rubber having a small iodine value (B) (Comparative Example 3) is as follows. Small number of breaks in constant elongation fatigue test. The vulcanizate (Comparative Example 4) of the rubber composition using the nitrile group-containing copolymer rubber (b) having an iodine value that is too small has too large a compression set. The vulcanizate of the rubber composition having an excessive amount of sulfur (Comparative Example 5) has a small elongation even in normal physical properties, but the rate of elongation decreases greatly when heat is applied, and the heat resistance is poor. It is also inferior to PS.

On the other hand, the vulcanizates of the rubber composition of the present invention (Examples 1 to 5) have a small compression set, excellent heat resistance, small HBU and PS, and a low number of fractures in the low elongation fatigue test. Large and difficult to break. Industrial applicability

The vulcanizate of the nitrile group-containing copolymer rubber of the present invention has excellent dynamic characteristics and heat resistance, and has characteristics of low compression set. Therefore, this vulcanized product is useful as hoses, tubes, seals, gaskets, boots, rolls, belts, diaphragms, etc., in which these characteristics are utilized, but especially for rolls and belts used in dynamic conditions. It is suitable for boots, diaphragms and the like.

Claims

The scope of the claims

1. A copolymer rubber containing a nitrile group having a unit content of 10/3 to 60% by weight of a 3 / 3-ethylenically unsaturated nitrile monomer and an iodine value of 180 to 430 (A) 5 to 50 parts by weight and α ,) 3-nitrile unsaturated nitrile monomer unit content 10 to 60% by weight, iodine value 40 to 100 nitrile group-containing copolymer rubber (I) 50 to 95 parts by weight Rubber component 100 parts by weight And 0.1 to 1.5 parts by weight of sulfur and at least one vulcanizing agent selected from 4,4'-dithiodimorpholine in terms of sulfur amount.

2. The nitrile group-containing copolymer rubber (Α) and the nitrile group-containing copolymer rubber (、) consist of 10 to 60% by weight of ひ / 3-ethylenically unsaturated nitrile monomer unit and The copolymer rubber according to claim 1, which is a copolymer rubber comprising units of at least one monomer selected from a monomer, a non-conjugated diene monomer and an α-olefin monomer in an amount of 40 to 90% by weight. Vulcanizable rubber composition.

3. The nitrile group-containing copolymer rubber (Α) and the nitrile group-containing copolymer rubber (Β) consist of 10% to 60% by weight of [3] ethylenically unsaturated nitrile monomer unit and 10% by weight of conjugated gen. 2. The vulcanizable rubber composition according to claim 1, which is a copolymer rubber comprising 40 to 90% by weight of a body unit.

4. The vulcanizable rubber composition according to any one of claims 1 to 3, wherein the nitrile group-containing copolymer rubber (Α) has an iodine value of 200 to 400.

5. The vulcanizable rubber composition according to any one of claims 1 to 4, wherein the nitrile group-containing copolymer rubber (Β) has an iodine value of 45 to 90.

6. The vulcanizability according to any one of claims 1 to 5, wherein the nitrile group-containing copolymer rubber (Α) has a viscosity of 221 (ML _{1 + 4} , 10 O :) 20 to 300. Rubber composition.

7. The vulcanizable rubber according to any one of claims 1 to 6, wherein the nitrile group-containing copolymer rubber (B) has a viscosity of 10 to 300 (ML _{1 + 4} , 100). Composition.

8. The rubber component is composed of 100 to 45 parts by weight of the nitrile group-containing copolymer rubber (A) and 100 to 45 parts by weight of the nitrile group-containing copolymer rubber (B) 55 to 90 based on 100 parts by weight of the rubber component. The vulcanizable rubber composition according to any one of claims 1 to 7, comprising parts by weight.

9. The vulcanizable rubber composition according to any one of claims 1 to 8, wherein the vulcanizing agent is contained in an amount of 0.2 to 1 part by weight in terms of sulfur based on 100 parts by weight of the rubber component.

10. A vulcanizate obtained by vulcanizing the vulcanizable rubber composition according to any one of claims 1 to 9.