JP3391052B2 - Oil resistant rubber and rubber composition thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is suitable for industrial material applications, excellent in oil resistance, and oil resistance, roll workability, mechanical properties, heat resistance, cold resistance, roses and compression permanent strain
The present invention relates to an oil resistant rubber having excellent resistance and a rubber composition containing the rubber. More particularly, the hydrogenated diene copolymer of random copolymer comprising a vinyl aromatic compound and a conjugated diene compound, thereby graft-polymerizing the nitrile group-containing vinyl monomer and mosquitoes carboxyl group-containing vinyl monomer The present invention relates to the oil-resistant rubber obtained as described above, and a rubber composition containing the rubber.

[0002]

2. Description of the Related Art Conventionally, natural rubber, styrene-butadiene copolymer rubber (SBR), polyisoprene rubber (IR), butyl rubber (IIR), acrylonitrile-butadiene copolymer have been used as rubber mainly for automobile parts. Rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene terpolymer rubber (EPDM),
Acrylic rubber (ACM) and the like are also known. However, in recent years, rubber of such an industrial material is required to have a high level of function that cannot satisfy the required performance at the conventional mechanical properties, heat resistance, cold resistance, and oil resistance. In order to improve the physical properties of these rubbers, the composition of the polymer and the type and amount of the compounding agent are mainly changed. However, it is difficult to improve all the mechanical properties, heat resistance, cold resistance, and oil resistance even if these changes are implemented. Blending of two or more kinds of polymers having different performances has also been carried out, but the combination is limited due to the compatibility between the polymers.

In recent years, thermoplastic elastomers, which are rubber-like soft materials and do not require a vulcanization step, have attracted attention in the field of automobile parts. In such a case, the vinyl aromatic compound-conjugated diene-vinyl aromatic compound block copolymerization resistant hydrogenation polymer (hereinafter abbreviated as hydrogenated block copolymer) of the thermoplastic elastomer has weather resistance,
Although it was excellent in heat resistance and mechanical properties, it was poor in oil resistance. Several proposals have been made regarding this hydrogenated block copolymer.

For example, Japanese Patent Laid-Open No. 50-14742.
The specifications such as JP-A-52-65551 disclose a composition obtained by blending a hydrogenated block copolymer with a hydrocarbon oil and an α-olefin polymer resin, and further, JP-A-59-20664. JP-A-59-13161
Japanese Patent Publication No. 3 discloses a method of partially cross-linking a composition obtained by mixing a hydrogenated block copolymer with a hydrocarbon oil, an α-olefin polymer resin, and an inorganic filler in the presence of an organic peroxide and a crosslinking aid. Has been done. However, the composition of the hydrogenated block copolymer obtained by these proposals,
Although it was excellent in rubber elasticity, it was poor in oil resistance.

Further, in Japanese Patent Publication No. 25977/1992, a hydrogenated block copolymer is grafted with a monomer having a nitrile group, and a hydrocarbon oil, an α-olefin polymer resin and an inorganic filler are added thereto. A blended composition is disclosed. This resin has improved oil resistance, and its use in the vulcanized rubber field is extremely limited because a softening agent must be used. Further, this publication only describes a graft hydrogenated block copolymer, and does not describe a hydrogenated random copolymer or a method of vulcanizing the composition for use.

[0006]

In rubber for vulcanization, mechanical properties, heat resistance, cold resistance, and oil resistance are all improved at the same time by changing the polymer composition, changing the type and amount of compounding agent, etc. Is difficult. In addition, the thermoplastic elastomer requires a softening agent, which limits the use in terms of compounding, and above all has a problem that the compression set is inferior to that of the vulcanized rubber.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to improve the oil resistance of a rubber based on a hydrogenated polymer of a random copolymer composed of a vinyl aromatic compound and a conjugated diene compound. result, by the nitrile group-containing vinyl monomer and mosquitoes carboxyl group-containing vinyl monomer to the hydrogenated polymer is graft-copolymerized, suitable for industrial material applications, excellent in oil resistance, and oil resistance , roll processability, mechanical properties, heat resistance, cold resistance, compression permanent strain
It was found that a rubber composition having an excellent balance with

That is, according to the present invention, the number average molecular weight of (1)-(a) vinyl aromatic compound and conjugated diene compound is 5,000 to 1,000,000, and the vinyl bond content of the diene portion is 10 to 10. A hydrogenated diene polymer, which is a random copolymer having a content of 90%, in which at least 50% or more of the olefinic unsaturated bond of the copolymer is hydrogenated by hydrogenating the diene polymer portion, and 50 to 95% by weight. to, (b) nitrile group-containing vinyl monomer and mosquitoes Rubo <br/> cyclohexyl group-containing vinyl monomer total 5-50 wt% Mooney viscosity obtained by graft copolymerization of (ML _{1+ 4} , 1
To provide an oil resistant rubber having a temperature of 00 ° C) of 30 to 150, and further, (2)-(a) 100 parts by weight of the graft copolymer rubber, (b) 0 to 200 parts by weight of a filler, and (C) A rubber composition comprising 0.01 to 10 parts by weight of an organic peroxide .

The vinyl aromatic compound as a monomer constituting the hydrogenated diene polymer obtained by hydrogenating a random copolymer comprising a vinyl aromatic compound and a conjugated diene compound in the present invention is preferably It is styrene, and α-methylstyrene and the like are also used. The conjugated diene monomer is preferably butadiene or isoprene, or a mixture of both.

The ratio of the vinyl aromatic compound and the conjugated diene compound is not particularly limited, but vinyl aromatic compound / conjugated diene compound = 5 to 60/95 to 40 (% by weight) is preferable. The molecular structure of this diene random copolymer may be linear, branched, radial or a combination thereof, and is not particularly limited.
These diene random copolymers are required to hydrogenate at least 50% or more of their olefinic unsaturated bonds, preferably 70% or more, more preferably 80% or more. Below this, it becomes difficult to substantially maintain heat resistance.

The number average molecular weight of these diene random copolymers is 5,000 to 1,000,000. 5,
000 or less, graft copolymer rubber (oil resistant rubber)
Has poor workability and mechanical properties. The vinyl bond content of the diene portion of this diene random copolymer is 10 to
It is 90%, preferably 20 to 80%, more preferably 25 to 75%, and particularly preferably 30 to 60%.
When the vinyl bond content is 10% or less or 90% or more, the flexibility of the graft copolymer rubber (oil resistant rubber) in the low temperature region is lowered. 1,2-bond, the control of the vinyl bond content of such 3,4-bond, ether, tertiary amine compounds, sodium, alkoxides of alkali metals such as potassium, phenoxide, is Ho phosphate salt used. The sequence of the vinyl aromatic compound and the conjugated diene compound of this diene copolymer is a random bond. When a hydrogenated copolymer of such a random copolymer is used, a vulcanized product of a rubber composition having an excellent compression set is superior to a case where a hydrogenated copolymer of a block copolymer is used. can get. The random copolymer can be obtained, for example, by performing anionic living polymerization in a hydrocarbon solvent using an organolithium initiator. Further, the branched polymer can be obtained by adding a necessary amount of a trifunctional or higher functional coupling agent after completion of the polymerization to perform coupling.

As the organic lithium initiator, n-butyllithium, sec-butyllithium, t-butyllithium and the like are used. Hexane, heptane, methylcyclopentane, cyclohexane, benzene, toluene, xylene, 2-methylbutene-1, 2-methylbutene-2 and the like are used as the hydrocarbon solvent. The polymerization may be carried out batchwise or continuously, and the polymerization temperature is usually 0 to
In the range of 120 ° C., the polymerization time is 10 minutes to 3 hours. The coupling agent is a trifunctional or higher functional coupling agent, and examples thereof include tetrachlorotin, butyltrichlorotin, tetrachlorogermanium, bis (trichlorosilyl) ethane, divinylbenzene, adipic acid diester, epoxidized liquid polybutadiene, and epoxy. Soybean oil, epoxidized linseed oil, tolylene diisocyanate, 1,2,4-benzenetriisocyanate and the like can be mentioned.

In the hydrogenation reaction, the diene-based random copolymer is dissolved in a hydrocarbon solvent and the temperature is set to 20 to 150 ° C. for 1 to 1
It is carried out in the presence of a hydrogenation catalyst under pressurized hydrogen of 00 kg / cm ² . As the hydrogenation catalyst, a catalyst in which a noble metal such as palladium, ruthenium, rhodium or platinum is supported on silica, carbon or diatomaceous earth, a complex catalyst such as ruthenium, rhodium or platinum, an organic carboxylic acid such as cobalt or nickel and an organic aluminum are used. Or a catalyst composed of organolithium, a titanium compound such as dicyclopentadienyl titanium dichloride, dicyclopentadienyl diphenyl titanium, dicyclopentadienyl titanium ditolyl, dicyclopentadienyl titanium dibenzyl and lithium, aluminum, magnesium A hydrogenation catalyst composed of an organometallic compound is used. By hydrogenating the diene-based random copolymer thus polymerized, a hydrogenated diene polymer which is the rubber-like copolymer of the present invention can be obtained.

Although the content of the hydrogenated diene polymer contained in the graft copolymer rubber of the present invention can be arbitrarily selected according to the purpose, it satisfies various physical properties such as mechanical properties and compression set of the rubber. To achieve this, the range is 50-95% by weight,
It is preferably 60 to 95% by weight. If the content is less than 50% by weight, only a graft copolymer rubber having a low viscosity can be obtained, resulting in poor processability and low physical properties.

The thus obtained component (1) - (a) a hydrogenated diene polymer, the component (1) - (b) graft polymerizing a nitrile group-containing vinyl monomer and mosquitoes carboxyl group-containing vinyl monomer By doing so, an oil resistant rubber is obtained. The oil-resistant rubber specified in the present invention is composed of the component (1)-
In (a) hydrogenated diene polymer, the component (1) - (b) addition of the nitrile group-containing vinyl monomer and mosquitoes carboxyl group-containing vinyl monomer graft copolymer obtained by graft-polymerizing, It may be a mixture of the graft copolymer and the copolymer of the monomer (b).

Examples of the nitrile group-containing vinyl monomer of the component (1)-(b) include acrylonitrile and methacrylonitrile. Examples of the carboxyl group-containing vinyl monomer include unsaturated carboxylic acids or derivatives thereof, specifically vinyl acetate, (meth) acrylic acid,
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, methoxyethyl (meth) acrylate, (meth)
Examples thereof include ethoxymethyl acrylate.
From these nitrile group-containing vinyl monomers and carboxyl group-containing vinyl monomers, one kind or two or more kinds are arbitrarily selected according to the balance of the oil resistance and the cold resistance of the desired rubber, and at any ratio. Can be combined. The composition ratio of these vinyl monomers, the total vinyl in the monomer polymerized, in the range of the nitrile group-containing vinyl monomer / the carboxyl group-containing vinyl monomer = 15 to 80/85 to 20 (wt%) It is preferable. The glass transition temperature of the graft copolymer produced by graft copolymerization and the copolymer not grafted is not particularly limited, but the content of the nitrile group-containing vinyl monomer is 80.
If it is more than 5% by weight, the glass transition temperature becomes high and the cold resistance of the graft copolymer rubber is impaired. Furthermore, in this, the vulcanization of the ease of the rubber composition, methoxyethyl (meth) acrylate or (meth) ethoxy methyl acrylate alone or, (meth) acrylic acid methoxyethyl or (meth) acrylic acid It is preferable to combine ethoxymethyl and one or more of the above monomers in the above ratio. While the total content of the graft copolymer contained in the rubber nitrile group-containing vinyl monomer and mosquitoes carboxyl group-containing vinyl monomer of the present invention can be arbitrarily selected depending on the purpose, the rubber of the machine The range is 5 to 50% by weight, preferably 5 to 40% by weight in order to satisfy various properties such as physical properties and compression set. When the content exceeds 50% by weight, only a graft copolymer rubber having a low viscosity can be obtained, resulting in poor processability and low physical properties.

The graft ratio of the graft copolymer rubber thus obtained is usually required to be 5% by weight or more. When the graft ratio of the obtained graft copolymer rubber is less than 5% by weight, the compatibility between the graft copolymer and the copolymer not grafted is insufficient, and the processability and mechanical properties are poor.

The method for producing a graft copolymer rubber of the present invention, the random copolymer hydrogenated diene polymer, is to graft a nitrile group-containing vinyl monomer and mosquitoes carboxyl group-containing monomer . As a method of grafting, solution grafting, melt grafting, water suspensions graft, and none of <br/> radiation graft may be employed. For example, in solution grafting, the hydrogenated diene polymer of the random copolymer and the soluble organic solvent of both the graft copolymer, for example, benzene, toluene, dissolve the hydrogenated diene polymer in tetrahydrofuran (THF), After adding the monomer and the radical initiator, the temperature is raised to start and complete the polymerization. According to this method, a graft copolymer rubber can be easily obtained industrially.

Examples of the radical initiator include benzoyl peroxide, lauroyl peroxide and t-
Examples thereof include organic peroxides such as butyl peroxy laurate, t-butyl peroxy acetate, t-butyl peroxy isopropyl carbonate and t-butyl peroxy benzoate. The amount of these radical initiators used is 100% of the monomers of the components (1)-(b) used.
0.05 to 30 parts by weight, preferably 0.
It is about 1 to 20 parts by weight. In the solution graft polymerization, 100 parts by weight of the total of the hydrogenated diene polymer of the component (1)-(a) and the monomer of the component (1)-(b) is used.
Usually, 100 to 1,000 parts by weight of an organic solvent and a radical initiator are used in the above range, and the polymerization is carried out at a polymerization temperature of 50 to 120 ° C. The graft copolymer rubber polymerized by the production method of the present invention is purified by drying after removing unreacted monomers and organic solvent by ordinary steam distillation.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the graft copolymer rubber thus produced is 30 to 150. When the Mooney viscosity is less than 30, mechanical properties are low, and when it exceeds 150, workability is poor. These Mooney viscosities are controlled by the type and amount of radical initiator.

The rubber composition of the present invention comprises (2)-(a ) 100 parts by weight of the graft copolymer rubber (oil resistant rubber) .
(B) 0 to 200 parts by weight of filler, and (c) organic peracid
Compound of 0.01 to 10 parts by weight.

In the composition of the present invention, for example, the graft copolymer rubber is softened by a kneading machine such as a Banbury mixer, a kneader, or a twin roll, and then the filler of the components (2)-(b) is blended. It is obtained by a kneading method, etc., and the addition method of each component, the order of addition, the kneading method, and the kneading equipment are not particularly limited. Also,
The method of adding / compounding and the order of addition of the crosslinking agents of components (2)-(c) are also not particularly limited, but it is preferred that they are added and compounded last because of the storage stability of the rubber composition.

In the composition of the present invention, a filler [component (2)-
(B)] can be added. This filler not only has the benefit of being able to lower the product cost as a bulking agent, but also has a positive effect on the mechanical properties. Examples of the filler include fumed silica, wet silica, fine quartz powder, diatomaceous earth, talc, carbon black, zinc white, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, mica. Examples thereof include powder, aluminum sulfate, calcium sulfate, barium sulfate, asbestos, glass fiber, organic reinforcing agent and organic filler.

The blending amount of these fillers is as follows.
0 to 100 parts by weight of the graft copolymer rubber (a)
It is 200 parts by weight, preferably up to 100 parts by weight. If the amount is more than 200 parts by weight, the kneading property and roll workability will be poor.

Next, as the components (2)-(c), an organic peroxide or the like which is usually used as a vulcanizing agent for rubber may be used. Examples of the organic peroxide used as a cross-linking agent include 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-butylperoxide, t-butylperbenzoate, 1,
1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide and the like, preferably 2,5-dimethyl-2,5. -Di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
It is 2,2'-bis (t-butylperoxy) -p-diisopropylbenzene.

The amount of the organic peroxide used as the crosslinking agent varies depending on the organic peroxide used,
0.01 to 10 parts by weight, preferably 0.1 to 100 parts by weight of the graft copolymer rubber of the component (2)-(a).
5 parts by weight.

If the amount of the organic peroxide used is too large, the crosslink density of the rubber component becomes too high, and the elongation of the vulcanized product of the obtained rubber composition decreases. When the rubber component is crosslinked, a bifunctional or higher functional vinyl monomer may be used as a crosslinking aid. Examples of the crosslinking aid include the following compounds. That is, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6
-Hexanediol dimethacrylate, polyethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 2,2'-bis (4-methacryloyldiethoxyphenyl) propane, trimethylolpropane triacrylate Trimethylolpropane trimethacrylate,
Pentaerythritol triacrylate, divinylbenzene, N, N'-methylenebisacrylamide, p-quinonedioxime, p, p'-dibenzoylquinonedioxime, triazinethiol, triallyl cyanurate,
Examples include triallyl isocyanurate and bismaleimide.

For the purpose of imparting other properties to the rubber composition of the present invention, known additives may be added within a range that does not impair the effects of the present invention. For example, processing aids such as metal oxides, amines, fatty acids and their derivatives; plasticizers such as phthalic acid derivatives and adipic acid derivatives; softeners such as lubricating oils, process oils, coal tar, castor oil, calcium stearate, as the antioxidant, for example phenylenediamines, e Sufe <br/> DOO, quinolines, cresols, phenols, dithiocarbamates metal salts; the heat stabilizers, for example iron oxide, Cerium, potassium hydroxide, iron naphthenate, potassium naphthenate; in addition, colorants, ultraviolet absorbers, flame retardants, oil resistance improvers, foaming agents, scorch inhibitors, tackifiers, lubricants and the like can be optionally mixed. The above additives are
If necessary, it may be added in the process of producing the rubber composition of the present invention, or may be added after the production of the rubber composition. The rubber composition of the present invention is obtained by kneading the above components,
After forming a crosslinkable rubber composition, molding and vulcanization can be performed. When vulcanizing this rubber composition, a crosslinking accelerator, a crosslinking aid, an accelerator aid, a crosslinking retarder and the like may be used in combination, if necessary. Crosslinking is performed by applying energy such as heat, electron beams, ultraviolet rays and electromagnetic waves. To crosslink (vulcanize) the rubber composition of the present invention,
Usually, at 80 to 200 ° C. for several minutes to 3 hours, 20 to 200
Vulcanization is performed under a pressure of kg / cm ² . Further, if necessary, secondary vulcanization is performed at 80 to 200 ° C. for 1 to 48 hours to obtain a product.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. [Synthesis of Base Rubber] Synthesis of Base Polymer After charging 2,500 g of degassed and dehydrated cyclohexane, 150 g of styrene and 350 g of 1,3-butadiene into a 5 liter autoclave, 3.5 g of tetrahydrofuran and 0.33 g of n-butyllithium. Was added to carry out temperature-rising polymerization at a polymerization temperature of 30 ° C to 80 ° C. After the conversion reached about 100%, 0.19 g of SiCl ₄ was added. Then, the solvent was removed by steam distillation, and the polymer was obtained by drying with a 120 ° C. hot roll. The styrene-butadiene random copolymer thus obtained has a vinyl bond content of 30%, a styrene content of 30% by weight,
It was 60% by weight of a branched polymer having 3 or more branches. Number average molecular weight by GPC analysis is 27,000, Mw / Mn is 1
It was 0.7. The styrene-butadiene random copolymer synthesized by hydrogenation was charged into a 3 liter autoclave to prepare a 15% cyclohexane solution. After substituting the system with nitrogen, a catalyst solution of nickel naphthenate: n-butyllithium: tetrahydrofuran = 1: 8: 20 (molar ratio) prepared in advance in another container was used as nickel for 2,000 mol of the olefin moiety. It was prepared to be 1 mol. After that, hydrogen was introduced into the reaction system, and hydrogenation reaction was performed at 70 ° C.
After controlling the hydrogenation rate from the absorbed amount of hydrogen, the hydrogen in the system was replaced with nitrogen. After repeating contact removal and solidification, roll drying is performed by a conventional method, and hydrogenation rate is 98%.
To obtain a hydrogenated styrene-butadiene random copolymer (Moonee viscosity 82: ML _{1 + 4} , 100 ° C.).

[Analysis Method] The amount of bound styrene was determined from a calibration curve by an infrared method based on the absorption of a phenyl group at 699 cm ^-1 . The vinyl bond content was determined by the infrared method (Morero method). The molecular weight and the molecular weight distribution are determined by gel permeation chromatography (GPC) [apparatus: Tosoh Corporation]
Made, 802A; Carrier: 0.5 ml / min TH
F: Polystyrene gel column: Showa Denko KK, GP
C-UT806L column; molecular weight: polystyrene equivalent]
I asked from. Hydrogenation rate (hydrogenation rate) was measured at 15% concentration 1
It was calculated from the decrease in the spectrum of the unsaturated bond part of the ¹ H-NMR spectrum at 00 MHz.

[Synthesis of Graft Copolymer Rubber] Synthesis Example 1 80 wt.% Of hydrogenated styrene-butadiene random copolymer was placed in a 1 liter separable flask equipped with a reflux condenser, a thermometer, a nitrogen inlet and a stirrer. A part was transferred and the system was replaced with nitrogen. To this was added 500 parts by weight of degassed toluene, and the mixture was dissolved by heating with stirring, and then a monomer and a radical initiator were added, and the temperature was raised to 95 ° C.
Polymerization was carried out while controlling the polymerization temperature for a certain period of time. After completion of the polymerization, the reaction mixture was taken out from the separable flask, toluene and unreacted monomers were removed by steam distillation, and the precipitated rubber-like polymer (graft copolymer rubber) was vacuum dried to obtain a polymer P- Got 1. The graft ratio of the graft copolymer rubber thus obtained was determined by the following method. A certain amount of the graft copolymer is put into methyl ethyl ketone in which the hydrogenated diene polymer and the graft copolymer are insoluble, and the mixture is stirred for a day and night to dissolve the free copolymer. The insoluble matter was separated from this, and the graft ratio of the grafted monomer was determined from this weight. Further, the composition of the obtained graft copolymer rubber was determined by the following method. The ratio of the hydrogenated diene polymer in the graft copolymer rubber is based on the polymerization conversion rate, and the ratio of the monomer is 100 MHz ¹³
It was determined from the ratio of the spectrum of each component of the C-NMR spectrum. The obtained graft ratio and composition of the graft copolymer rubber are also shown in Table 1.

[0032]

[Table 1]

Synthesis Examples 2 to 4 In the same manner as in Synthesis Example 1, the amount of base rubber and the amount of radical initiator were changed with the monomer composition shown in Table 1 to obtain the desired polymers P-2 to P-2. -4 was obtained. [Production of rubber composition and evaluation thereof] Next, an example of producing a rubber composition of the present invention using the graft copolymer rubbers of the present invention produced in the above-mentioned Synthesis Examples 1 to 4 will be described.

Examples 1 to 4, Comparative Examples 1 to 3 Graft copolymer rubbers produced in Synthesis Examples 1 to 4 (polymer P
-1 to P-4) were used as the component (A), and the respective components were kneaded and blended by an internal mixer according to the blending ratio shown in Table 2 by an ordinary method to produce respective rubber compositions. As comparative examples of the component (A), hydrogenated styrene-butadiene random copolymer rubber (base rubber in the present invention), chloroprene rubber / neoprene GRT.
(Product name, made by Du-Pont), acrylic rubber / ARE
X310 (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) (B)
As a reinforcing filler for the components, FEF carbon black seast SO (trade name, manufactured by Tokai Carbon Co., Ltd.), M
AF carbon black seast 116 (trade name, manufactured by Tokai Carbon Co., Ltd.), (C) component as an organic peroxide, Percadox 14/40 (trade name, manufactured by Kayaku Akzo Co., Ltd.), zinc Table 2, blending agent of vulcanization, magnesium oxide, potassium stearate, sodium stearate, and sulfur as other components, a cross-linking aid, Barnock PM (trade name, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), and stearic acid. Used in.

[0035]

[Table 2]

The initial physical properties, aging test, oil resistance, cold resistance and compression set of each rubber composition thus produced are
It evaluated based on IS K6301 and the conditions shown below. The results are shown in Table 3.

[0037]

[Table 3]

Initial physical properties: Examples 1 to 4, Comparative Example 1; 17
Press vulcanization at 0 ° C for 20 minutes. Comparative Example 2; 150 ° C. × 20
Minute press vulcanization. Comparative Example 3; Secondary vulcanization of gear oven at 175 ° C. for 4 hours after press vulcanization at 170 ° C. for 20 minutes. Aging test: 150 ° C x 168 hours gear oven. Oil resistance: Using JIS # 3 oil, soak at 100 ° C for 72 hours. Cold resistance: low temperature torsion test. Compression set: 25% compression, 120 ° C x 72 hours gear oven.

From the results shown in Table 3, in Examples 1 to 4, hydrogenated styrene-butadiene random copolymer rubber was graft-copolymerized with acrylonitrile and acrylic acid ester to obtain mechanical properties, heat resistance and cold resistance. It can be seen that a rubber or rubber composition having excellent oil resistance can be obtained. On the other hand, Comparative Example 1 is a graft-unmodified hydrogenated styrene-butadiene random copolymer rubber, which is inferior in oil resistance. Comparative Example 2 is a conventional oil resistant rubber having oil resistance but poor heat resistance.
Comparative Example 3 is a conventional oil resistant rubber, which has heat resistance and oil resistance, but is inferior in mechanical properties.

[0040]

The present invention exhibits a novel oil resistance obtained vinyl nitrile group-containing a specific proportion of the hydrogenated copolymer rubber monomer and mosquitoes carboxyl group-containing vinyl monomer by graft copolymerization The present invention provides a rubber and a rubber composition thereof, and according to the present invention, is excellent in oil resistance and oil resistance.
And sex, mechanical properties, heat resistance, cold resistance, Ba and compression permanent strain
An oil resistant rubber excellent in lance and a rubber composition are obtained. The conventional oil-resistant rubber has a poor physical property balance, and its use in applications requiring both oil resistance-heat resistance or oil resistance-mechanical properties has been limited, but the oil-resistant rubber and rubber according to the present invention have been limited. The composition has an excellent balance, and it is possible to develop the use which is limited in the conventional rubber. The rubber composition of the present invention can be widely applied to various fields such as belts, hoses, gaskets and boots.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-60948 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 279/00-279/06

Claims (2)

(57) [Claims] 1. A number-average molecular weight of (a) a vinyl aromatic compound and a conjugated diene compound is 5,000 to 1,0.
And the vinyl bond content of the diene portion is 1
Hydrogenated diene polymer 50-95 in which the diene polymer portion is hydrogenated to hydrogenate at least 50% or more of the olefinically unsaturated bond of the copolymer. the weight%, (b) nitrile group-containing vinyl monomer and mosquitoes carboxyl group-containing vinyl monomer
Of the Mooney viscosity (ML _{1 + 4} , 100 ° C.) obtained by graft-copolymerizing a total of 5 to 50% by weight of
Oil resistant rubber. 2. (a) The oil resistant rubber 100 according to claim 1.
A rubber composition comprising 1 part by weight, (b) 0 to 200 parts by weight of a filler, and (c) 0.01 to 10 parts by weight of an organic peroxide .