JP2003342418A - Crosslinkable rubber composition and crosslinked product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nitrile group-containing copolymer rubber crosslinked product excellent in mechanical characteristics and having a small permanent compression set, and a crosslinkable, nitrile group-containing copolymer rubber composition excellent in scorch stability as the material for the same. <P>SOLUTION: The crosslinkable rubber composition comprises 100 g of a nitrile group-containing copolymer rubber (A), which contains 10-60 wt.% of a structural unit derived from an α,β-ethylenically unsaturated nitrile monomer and has an iodine value of at most 100, and, incorporated therewith, 1-30 millimole of an organic peroxide (B), 1.5-20 millimole of a bismaleimide compound (C) and 0.05-8.5 millimole of a quinone dioxime compound (D). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crosslinkable nitrile group-containing copolymer rubber composition and a crosslinked product obtained by crosslinking the same.

[0002]

As a rubber material having excellent heat resistance and oil resistance, a hydrogenated acrylonitrile-butadiene copolymer rubber obtained by hydrogenating an acrylonitrile-butadiene copolymer rubber is known. For cross-linking the hydrogenated acrylonitrile-butadiene copolymer rubber, an organic peroxide can be used in addition to sulfur, similar to the cross-linking of the conventional diene rubber. When an organic peroxide is used, the crosslinking efficiency can be increased by using a radically polymerizable polyfunctional monomer such as m-phenylene bismaleimide or triallyl isocyanurate as a crosslinking aid.

For example, in JP-A-7-330957, a hydrogenated acrylonitrile-butadiene copolymer rubber having a bound acrylonitrile amount of 30 to 40% by weight is mixed with carbon black, a maleimide compound and an organic peroxide crosslinking agent. By crosslinking the crosslinkable rubber composition,
It has been reported that a crosslinked product having a balance of hardness, elongation, compression set and the like required as a seal member, and further having improved durability against a fluorine-based solvent can be obtained.
However, although this crosslinkable rubber composition gives a crosslinked product having a small compression set, it tends to cause scorch during processing before crosslinking, and has poor processing stability.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to crosslink a rubber composition which does not cause scorch during processing, has excellent mechanical properties, and has a small compression set. To provide a cross-linked product.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that the content of the structural unit derived from the α, β-ethylenically unsaturated nitrile monomer and the iodine value are With respect to the nitrile group-containing copolymer rubber in a specific range, an organic peroxide, a rubber composition containing a bismaleimide compound and a quinonedioxime compound in specific proportions respectively, does not cause scorch during processing, It was found that the crosslinked product has excellent mechanical properties and a small compression set, and based on this finding, the present invention has been completed.

Thus, according to the present invention: Nitrile group-containing copolymer rubber (A) 100 having an iodine value of 100 or less, in which the content of structural units derived from an α, β-ethylenically unsaturated nitrile monomer is 10 to 60% by weight.
1 to 30 mmol of the organic peroxide (B), 1.5 to 20 mmol of the bismaleimide compound (C) and 0.05 to 8.5 mmol of the quinonedioxime compound (D) per g. Crosslinkable rubber composition, 2. The crosslinkable rubber composition according to 1, wherein the amount of the quinonedioxime compound (D) used is 0.02 to 0.17 mol times the total amount of the organic peroxide (B) and the bismaleimide (C) used. , 3. 3. A crosslinked product obtained by crosslinking the crosslinkable rubber composition according to the above 1 or 2. The crosslinked product described in 3 above, which is a constituent member of a seal component, is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The crosslinkable rubber composition of the present invention comprises
Iodine number 10 in which the content of the structural unit derived from the α, β-ethylenically unsaturated nitrile monomer is 10 to 60% by weight
1 to 30 mmol of the organic peroxide (B), 1.5 to 20 mmol of the bismaleimide compound (C) and quinone dioxime compound (D) per 100 g of the nitrile group-containing copolymer rubber (A) of 0 or less. It is characterized by containing 0.05 to 8.5 mmol.

The nitrile group-containing copolymer rubber (A) used in the present invention is a rubber obtained by copolymerizing an α, β-ethylenically unsaturated nitrile monomer with another monomer by a known method. is there.

Examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like, and acrylonitrile is preferable. The content of the structural unit derived from the α, β-ethylenically unsaturated nitrile monomer in the nitrile group-containing copolymer rubber (A) is 10 to 60% by weight, preferably 12 to 55% by weight, more preferably Is 15-50
% By weight. If the content of the structural unit is too small, the oil resistance of the crosslinked product may be poor, and if it is too large, the cold resistance may be poor.

Examples of the monomer copolymerizable with the α, β-ethylenically unsaturated nitrile monomer include conjugated diene monomer, non-conjugated diene monomer and α-olefin. . As the conjugated diene monomer, for example,
1,3-butadiene, isoprene, 2,3-dimethyl-
1,3-Butadiene, 1,3-pentadiene and the like can be mentioned, with 1,3-butadiene being preferred. The non-conjugated diene monomer preferably has 5 to 12 carbon atoms,
Examples include 1,4-pentadiene, 1,4-hexadiene, vinylnorbornene, dicyclopentadiene and the like. As the α-olefin, those having 2 to 12 carbon atoms are preferable, and ethylene, propylene, 1-butene, 4-
Methyl-1-pentene, 1-hexene, 1-octene and the like are exemplified.

Further, a nitrile group-containing copolymer rubber (A)
Is a copolymer of an aromatic vinyl monomer, a fluoroolefin monomer, an α, β-ethylenically unsaturated carboxylic acid monomer, etc., in addition to the above-mentioned monomers, within a range not impairing the object of the present invention. It may be obtained by Further, these monomers may be a copolymerizable anti-aging agent. The content of these monomer units in the nitrile group-containing copolymer rubber (A) is preferably 0 to 30% by weight, more preferably 0 to 25% by weight or less.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinylpyridine and the like. Examples of the fluoroolefin monomer include fluoroethyl vinyl ether, fluoropropyl vinyl ether, o-trifluoromethylstyrene, vinyl pentafluorobenzoate, difluoroethylene, tetrafluoroethylene and the like. Examples of the α, β-ethylenically unsaturated carboxylic acid type monomer include α, β-ethylenically unsaturated monocarboxylic acid such as acrylic acid and methacrylic acid; α, β such as ethyl acrylate, butyl acrylate and methoxyethyl acrylate. -Ethylenically unsaturated monocarboxylic acid ester; α, β-ethylenically unsaturated polyvalent carboxylic acid such as itaconic acid, fumaric acid and maleic acid; α, β-ethylenically unsaturated such as itaconic anhydride and maleic anhydride Polycarboxylic acid anhydride; α, β- such as monobutyl itaconic acid and dibutyl itaconic acid
Ethylenically unsaturated polycarboxylic acid ester;
To be Examples of the copolymerizable antiaging agent include N-
(4-anilinophenyl) acrylamide, N- (4-
Anilinophenyl) methacrylamide, N- (4-anilinophenyl) cinnamamide, N- (4-anilinophenyl) crotonamide, N-phenyl-4- (3-vinylbenzyloxy) aniline, N-phenyl-4 −
(4-vinylbenzyloxy) aniline and the like can be mentioned.

The iodine value of the nitrile group-containing copolymer rubber (A) is 100 or less, preferably 80 or less, more preferably 60 or less. If the iodine value is too large, the heat resistance will be poor.

When the α, β-ethylenically unsaturated nitrile monomer and the conjugated diene monomer are copolymerized, the iodine value often becomes large. In this case, the iodine value may be lowered by hydrogenating the carbon-carbon unsaturated bond of the copolymer rubber (A) by a known method. The hydrogenation method is not particularly limited, and a known method may be used.

The Mooney viscosity ML _{1 + 4} , (100 ° C.) of the nitrile group-containing copolymer rubber (A) is preferably 10 to 10.
It is 300, more preferably 20 to 250, particularly preferably 30 to 200. If the Mooney viscosity is too small, the mechanical properties of the crosslinked product may be poor, and if it is too large, the processability may be poor.

The organic peroxide (B) used in the present invention is not particularly limited as long as it is used as a rubber crosslinking agent, and conventionally known organic peroxide crosslinking agents can be used.

Examples of the organic peroxide (B) include dialkyl peroxide, diacyl peroxide, and peroxy ester, and dialkyl peroxide is preferable. Examples of dialkyl peroxides include dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne, and 2,5-dimethyl-. 2,5
-Di (t-butylperoxy) hexane, 1,3-bis (t-butylperoxyisopropyl) benzene and the like can be mentioned. As the diacyl peroxide, for example,
Examples thereof include benzoyl peroxide and isobutyryl peroxide. Examples of peroxyesters include 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane and t-butylperoxyisopropyl carbonate. The compounding amount of the organic peroxide (B) with respect to the nitrile group-containing copolymer rubber (A) is 1 to 30 mmol per 100 g of the rubber (A),
Preferably 3 to 24 mmol, more preferably 5 to 18
It is millimoles. If the blending amount of the organic peroxide (B) is too small, the crosslink density is lowered and the compression set is increased. If the blending amount of the organic peroxide (B) is too large, the rubber elasticity of the crosslinked product may be insufficient.

The bismaleimide compound (C) used in the present invention may be a compound having two maleimide skeletons, but a compound having two maleimides bonded to an aromatic ring is usually used. Examples of such bismaleimide include phenylene bismaleimide and naphthene bismaleimide, and in the present invention, phenylene bismaleimide is most preferable. Specific examples of the phenylene bismaleimide include N, N'-m-phenylene bismaleimide, N, N'-p-phenylene bismaleimide, N,
N'-m-phenylene (1-methyl) bismaleimide,
N, N'-m-phenylene (4-ethyl) bismaleimide, N, N'-m-phenyle-4-methylbismaleimide, N, N'-2,7-naphthene bismaleimide, N,
N'-m-naphthene bismaleimide etc. are mentioned.
Among these, N, N'-m-phenylene bismaleimide is preferable from the viewpoints of easy availability and easy handling. The compounding amount of the bismaleimide compound (C) with respect to the nitrile group-containing copolymer rubber (A) is 100% rubber (A).
1.5 to 20 mmol per g, preferably 3 to 23
Mmol, more preferably 7 to 15 mmol. If the blending amount of the bismaleimide compound (C) is too small, the effect of improving the compression set is small, and conversely if it is too large, the hardness increases and the elongation decreases remarkably, and a crosslinked product having sufficient rubber elasticity cannot be obtained. .

The quinonedioxime compound (D) used in the present invention is p-benzoquinonedioxime or a derivative thereof, preferably a compound represented by the following general formula (1).

[0020]

[Chemical 1]

(In the formula, R ₁ and R ₂ are independently an acyl group or hydrogen.)

The acyl group in the formula (1) has 1 carbon atom.
Those having a number of 20 to 20 are usually used, and for example, acetyl, propionyl, and benzoyl groups are preferably used. Specific examples of the quinonedioxime compound (D) include p-
Examples thereof include benzoquinone dioxime, 4,4′-diacetylbenzoquinone dioxime, 4,4′-dipropionyl benzoquinone dioxime and 4,4′-dibenzoylbenzoquinone dioxime. Among these,
Most preferred is 4,4'-dibenzoylbenzoquinone dioxime. The compounding amount of the quinone dioxime compound (D) with respect to the nitrile group-containing copolymer rubber (A) is 1
It is 0.05 to 8.5 mmol, preferably 0.2 to 7.5 mmol, and more preferably 0.5 to 6 mmol per 100 g. If the blending amount of the quinonedioxime compound (D) is too small, scorch is likely to occur, resulting in poor workability. Conversely, if it is too large, the compression set becomes large.

In the present invention, the amount of the quinonedioxime compound (D) used is 0.02 to 0.17 mol times the total amount of the organic peroxide (B) and the bismaleimide (C) used. Is preferred, and a molar ratio of 0.04 to 0.15 is more preferred. Quinone dioxime compound (D)
If the amount used is too small, the effect of suppressing scorch cannot be obtained, which may make efficient molding difficult. On the other hand, if the amount is too large, the compression set is increased due to a decrease in crosslink density, and a crosslinked product having desired physical properties may not be obtained.

The crosslinkable rubber composition of the present invention may contain a polyfunctional monomer such as cyanurate or polyvalent acrylate as a crosslinking aid for the organic peroxide (B). As cyanurate, triallyl cyanurate,
Triallyl isocyanurate and the like are preferable, and as the polyvalent acrylate, trimethylolpropane trimethacrylate and the like are preferable. These crosslinking aids are clay,
You may mix and disperse | distribute in calcium carbonate, silica, etc. The type and blending amount of these cross-linking aids are not particularly limited, and may be determined according to the use of the cross-linked product, required performance, type of organized oxide, and the like.

As a cross-linking agent, an organic peroxide (B)
You may use together a sulfur type crosslinking agent. Examples of the sulfur-based cross-linking agent include sulfur such as powdered sulfur and precipitated sulfur; organic sulfur compounds such as 4,4′-dithiomorpholine, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and polymer polysulfides;

The crosslinkable rubber composition of the present invention is a compounding agent generally used for rubber, for example, reinforcing agents such as carbon black, silica, short fibers; calcium carbonate, clay,
It may contain a filler such as talc and calcium silicate; a plasticizer; a pigment; an antiaging agent; a tackifier; a processing aid; a scorch inhibitor. Further, the crosslinkable rubber composition of the present invention may contain a rubber or resin other than the nitrile group-containing copolymer rubber (A) in a range that does not substantially impair the effects of the present invention.

The method for preparing the crosslinkable rubber composition of the present invention is not particularly limited, and may be a general method for preparing a crosslinkable rubber composition. For example, an appropriate mixing method such as roll mixing, Banbury mixing, screw mixing, and solution mixing can be adopted. The mixing order is not particularly limited, but after sufficiently mixing components that are difficult to react or decompose with heat, a crosslinking agent or the like that easily reacts or decomposes with heat may be mixed in a short time at a temperature at which the reaction or decomposition does not occur. .

The method for molding the above-mentioned crosslinkable rubber composition is not particularly limited. Any method such as compression molding, injection molding, transfer molding or extrusion molding can be used. The cross-linking method may be selected according to the shape of the cross-linked product, and may be either a method of simultaneously performing molding and cross-linking or a method of cross-linking after molding.

The crosslinked product of the present invention is obtained by crosslinking the above-mentioned crosslinkable rubber composition. As a method for crosslinking the crosslinkable rubber composition, the rubber composition may be heated to a predetermined temperature or higher. Generally, the molding is performed by the above method and then heated, or the molding and heating are performed at the same time.

The crosslinking temperature is preferably 100 to 200.
C., more preferably 130 to 195.degree. C., and particularly preferably 140 to 190.degree. If the temperature is too low, the crosslinking time may be long and the crosslinking density may be low. If the temperature is too high, molding may be defective. The cross-linking time varies depending on the cross-linking method, cross-linking temperature, shape, etc., but is preferably 1 minute to 4 hours from the viewpoint of cross-linking density and production efficiency.

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

Depending on the shape and size of the crosslinked product, the interior may not be crosslinked even if the surface is crosslinked. In such a case, after crosslinking as described above, secondary crosslinking which maintains the high temperature state may be performed.

Since the crosslinked product of the present invention has excellent mechanical properties and a small compression set, it can be used in various applications.
Its application is not particularly limited, and for example, it can be used for sealers, rubber belts, rubber rolls, industrial products such as rubber hoses or parts thereof, as well as packers used in oil wells, gas wells, out pre-benders, pipe protectors, etc. it can. Examples of the seal include rotating seals, swinging seals, reciprocating seals, and stationary seals. Examples of motion seals include oil seals, piston seals, and mechanical seals, and examples of stationary seals include O-rings and various gaskets. Examples of the rubber belt include a flat belt, a V belt, a V ribbed belt, a round belt, a square belt, and a toothed belt. As the rubber roll, there are rolls that are parts of OA equipment such as printing equipment and copying equipment; rolls for fiber processing such as drawing rolls for spinning and draft rolls for spinning; iron making rolls such as bridle rolls, snubber rolls and steering rolls. Can be mentioned. Rubber hose
Single tube rubber hose, multi-layer rubber hose, braided reinforcement hose,
Examples include cloth-wrapped reinforcement hoses. Since the crosslinked product of the present invention has low mechanical properties and a small compression set, it is particularly suitable for seals and rubber belts, and most suitable for seals.

[0034]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. Parts and% are, unless otherwise specified,
It is based on weight. The evaluation method is as follows.

(1) Mooney viscosity The Mooney viscosity of the crosslinkable rubber composition is JIS K6300.
Was measured at 100 ° C.

(2) Stability of scorch Mooney scorch time (t5) and (t35) are determined by JI
It was measured at 145 ° C. according to SK6300. The greater the Mooney scorch times t5 and t35, the better the scorch stability.

(3) Tensile strength and elongation The prepared crosslinkable rubber composition was subjected to 170 ° C. and a pressing pressure of 10
Cross-linking was performed at MPa for 20 minutes to obtain a sheet having a thickness of 2 mm. Punch this sheet using a number 3 dumbbell,
A test piece was prepared. Using these test pieces, JIS
According to K 6251, the tensile strength and elongation of the crosslinked product were measured as mechanical properties.

(4) Hardness According to JIS K 6253, the hardness of the crosslinked product (the above test piece) was measured using a durometer hardness tester type A type.

(5) Compression set In accordance with JIS K 6254, 17 crosslinkable rubber compositions were prepared.
Cross-linking was performed at 0 ° C. for 20 minutes at a pressing pressure of 10 MPa, and then secondary cross-linking was performed at 150 ° C. for 4 hours to obtain a cylindrical test piece. This test piece was used to measure the compression set after holding it at 150 ° C. for 168 hours in a 25% compressed state.

Example 1 Copolymer rubber A (Zetpol 331) containing a nitrile group
0, manufactured by Nippon Zeon Co., hydrogenated acrylonitrile-butadiene copolymer rubber, acrylonitrile unit content 24%,
Iodine number 15, Mooney viscosity ML _{1 + 4} , (100 ° C)
70) 100 parts, carbon black (ASTM D17
Classification according to 65; N550) 65 parts, trioctyl trimellitate (plasticizer) 10 parts, diphenylamine anti-aging agent 1 part and mercaptobenzimidazole zinc salt (anti-aging agent) 1 part were kneaded in Banbury at 50 ° C. After that, 1,3-bis (t-butylperoxyisopropyl) benzene (organic peroxide) 3 parts (8.88 mmol), N, N′-m-phenylene bismaleimide 2 parts (7.46 mmol) and 0.25 parts (0.72 mmol) of 4,4′-dibenzoylquinonedioxime was added and kneaded with an open roll at 40 ° C. to prepare a crosslinkable rubber composition. The amount of 4,4′-dibenzoylquinone dioxime used is about 0.044 mol of the total amount of 1,3-bis (t-butylperoxyisopropyl) benzene and N, N′-m-phenylene bismaleimide used. Double.

The Mooney scorch time was measured for this crosslinkable rubber composition. Furthermore, using a test piece prepared from this crosslinkable rubber composition, the tensile strength of the crosslinked product, elongation,
Hardness and compression set were evaluated. The results are shown in Table 1.

Example 2 A crosslinkable rubber composition was prepared in the same manner as in Example 1 except that the amount of 1,3-bis (t-butylperoxyisopropyl) benzene was changed to 3.6 parts (10.65 mmol). Manufactured. The amount of 4,4′-dibenzoylquinone dioxime used is about 0.04 mol of the total amount of 1,3-bis (t-butylperoxyisopropyl) benzene and N, N′-m-phenylene bismaleimide used. Double. This crosslinkable rubber composition was used and evaluated in the same manner as in Example 1.
The results are shown in Table 1.

Example 3 The amount of 4,4'-dibenzoylquinone dioxime was adjusted to 0.7.
A crosslinkable rubber composition was produced in the same manner as in Example 2 except that the amount was changed to 5 parts (2.17 mmol). 4,4 '
-The amount of dibenzoylquinone dioxime used is 1,3-
It was about 0.12 mol times the total amount of bis (t-butylperoxyisopropyl) benzene and N, N'-m-phenylene bismaleimide used. This crosslinkable rubber composition was used and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4 A crosslinkable rubber was prepared in the same manner as in Example 3 except that the amount of 1,3-bis (t-butylperoxyisopropyl) benzene was changed to 4.2 parts (12.43 mmol). A composition was produced. The amount of 4,4′-dibenzoylquinone dioxime used is about 0.11 mol of the total amount of 1,3-bis (t-butylperoxyisopropyl) benzene and N, N′-m-phenylene bismaleimide used. It was double. This crosslinkable rubber composition was used and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 A crosslinkable rubber composition was produced in the same manner as in Example 1 except that 4,4'-dibenzoylquinone dioxime was not added. This crosslinkable rubber composition was used and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 The amount of 4,4'-dibenzoylquinone dioxime was changed to 5 parts (14.44 mmol), and the nitrile group-containing copolymer rubber A was replaced with the nitrile group-containing copolymer rubber B (Zet).
pol 2010, manufactured by Zeon Corporation, hydrogenated acrylonitrile-butadiene copolymer rubber, acrylonitrile unit content 36%, iodine value 11, Mooney viscosity M
A crosslinkable rubber composition was produced in the same manner as in Example 2 except that 100 parts of L _{1 + 4} , (100 ° C.) 85) was used. This crosslinkable rubber composition was used and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3 The amount of 4,4'-dibenzoylquinone dioxime was adjusted to 0.5.
Part (1.44 mmol) and replaced with 2 parts (7.46 mmol) of N, N′-m-phenylene bismaleimide, and 1.5 parts of triallyl isocyanurate (TAIC).
Part (6.02 mmol), and instead of the nitrile group-containing copolymer rubber A, 100 parts of the nitrile group-containing copolymer rubber B was used to produce a crosslinkable rubber composition in the same manner as in Example 2. did. This crosslinkable rubber composition was used and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0048]

[Table 1]

According to Table 1, Comparative Example 1 in which 4,4'-dibenzoylquinone dioxime is not blended has a short Mooney scorch time at t35 and is poor in scorch stability. On the contrary, Comparative Example 2 in which the amount of 4,4′-dibenzoylquinonedioxime added exceeds the range of the present invention.
Has excellent scorch stability, but has a large compression set. Comparative Example 3, which did not use N, N'-m-phenylene bismaleimide, also has excellent scorch stability, but has a large compression set.
On the other hand, Examples 1 to 1 using the rubber composition of the present invention
No. 4 shows excellent properties in all of scorch stability, mechanical properties, and compression set.

[0050]

According to the present invention, there is provided a crosslinkable rubber composition which does not cause scorch during processing. Then, by crosslinking this crosslinkable rubber composition, a crosslinked product having excellent mechanical properties and a small compression set can be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16J 15/10 F16J 15/10 Y F term (reference) 3J040 BA01 EA16 FA06 HA02 HA21 4H017 AA03 AB17 AC09 AD01 AE02 4J002 AC071 BB021 BB111 BB171 BC061 BC091 BD121 BD131 BD151 BE041 BF011 BG001 BG011 BG041 BG091 BG101 BH021 BJ001 BK001 BL001 EK036 EK046 EK056 ES018 EU027 FD010 FD140 FD146 FD147 FD150

Claims (4)

[Claims] 1. A alpha, beta-content of the structural unit ethylenic derived from an unsaturated nitrile monomer is 10 to 60 wt% der
That per iodine value of 100 or less of the nitrile group-containing copolymer rubber (A) 100 g, organic peroxide (B) 1 to 30
Mmol, bismaleimide compound (C) 1.5 to 20
0.05 mmol and quinone dioxime compound (D)
A crosslinkable rubber composition containing about 8.5 mmol. 2. The use amount of the quinone dioxime compound (D) is 0.02 to 0.17 mole times the total use amount of the organic peroxide (B) and the bismaleimide (C). Crosslinkable rubber composition. 3. A crosslinked product obtained by crosslinking the crosslinkable rubber composition according to claim 1. 4. A seal part comprising the crosslinked product according to claim 3.