JP3448782B2 - Rubber composition and rubber - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention comprises a hydrogenated diene-based copolymer, a graft modified product of the hydrogenated diene-based copolymer, a nitrile-modified acrylate-based copolymer, etc. The present invention relates to a rubber composition and rubber suitable as an industrial material having excellent properties.

[0002]

2. Description of the Related Art A method of bringing out the performance which cannot be obtained by a single rubber by blending two or more kinds of rubber has been used for a long time. In addition to imparting new performance, blending techniques are also used for the purpose of improving processability and reducing raw material costs. As a typical example, a blend composition of styrene-butadiene copolymer rubber (SBR) and butadiene rubber (BR) as a material for a tire tread, and SBR and ethylene-propylene-diene ternary as a material for a tire sidewall. Copolymer rubber (EPD
The blend composition of M) etc. are mentioned. A blend of a saturated rubber and a diene rubber such as the latter is intended to improve heat resistance and weather resistance, particularly ozone resistance, but the mechanical properties of the blend are deteriorated by blending. The tendency was generally. This tendency is particularly remarkable when the partner to be blended with the saturated rubber is a highly polar elastomer, and the blended rubber cannot be put to practical use because of its poor mechanical properties.

[0003]

In recent years, the engine temperature of automobiles has risen due to demands for comfort and reliability in a series of automobile exhaust gas regulations, power steering, air conditioning, exhaust gas converters, etc., and a compact hood assembly is also provided. The temperature in the engine room is rising due to. Furthermore, high power and high speed performance are raising the temperature of the engine, oil, cooling water and fuel. Due to the high temperature of automobile engines and the high speed and high performance of general industrial machinery, there has been a strong demand for oil resistant rubber materials with excellent durability and heat resistance. Conventional chloroprene rubber (CR) and butadiene-acrylonitrile Polymer rubber (NBR) is no longer able to meet the demand. An acrylate-based copolymer (acrylic rubber) is a rubber material that meets such requirements, but its processability, vulcanization moldability, mechanical properties, and cold resistance are insufficient, and its solution is expected. .

[0004]

In order to solve the above-mentioned problems, the present inventors have synthesized various compounds mainly containing a hydrogenated diene-based copolymer and acrylic rubber, and modifying both components from the polymerization stage. Then, these were blended to evaluate workability, vulcanization physical properties and the like, and as a result of research, the present invention was reached. That is,
According to the present invention, the diene polymer portion of the random copolymer (A) composed of the vinyl aromatic compound and the conjugated diene compound is hydrogenated to obtain 5 parts of the olefinic unsaturated bond of the copolymer.
A hydrogenated diene copolymer having 0% or more hydrogenated,
(B) A modified hydrogenated diene-based copolymer obtained by graft-copolymerizing the hydrogenated diene-based copolymer with a nitrile group-containing vinyl monomer and / or a -COO-bond-containing vinyl monomer, (C) contains a nitrile-modified acrylate copolymer and a cross-linking agent, and the mixing ratio of the components ((A) + (B)) and the component (C) is 90:10 to 50:50 by weight, and And a compounding ratio of the component (A) and the component (B) in a weight ratio of 0: 100 to 100: 0. In the present invention, the crosslinking agent is organic.
It is a peroxide and the rubber component ((A) + (B)
+ (C)) relative to 100 parts by weight, distribution of the organic peroxide
A rubber composition having a combined ratio of 0.5 to 10 parts by weight is provided . Furthermore, the present invention provides that the rubber composition of the present invention is crosslinked.
A rubber characterized by being provided .

A vinyl aromatic compound as a monomer constituting a hydrogenated diene copolymer obtained by hydrogenating a random copolymer of (A) a vinyl aromatic compound and a conjugated diene compound in the present invention. Is preferably styrene, and α-methylstyrene and the like can also be used.
The conjugated diene compound is preferably butadiene or isoprene, or may be a mixture of both. The ratio of the constituent component consisting of the vinyl aromatic compound and the constituent component consisting of the conjugated diene compound in the diene copolymer is usually vinyl aromatic compound / conjugated diene compound = 5 to 60/95.
40 (wt%), preferably 10-30 / 90-70
(% By weight). The molecular structure of the diene-based copolymer is a random copolymer and may be linear, branched, radial or a combination thereof, and is not particularly limited. The diene copolymer is required to hydrogenate 50% or more of its olefinic unsaturated bond, preferably 70% or more, more preferably 8% or more.
0% or more is hydrogenated. If it is less than 50%, it becomes difficult to maintain heat resistance.

The number average molecular weight of the diene copolymer is usually 5,000 to 1,000,000. If it is less than 5,000, the rubber composition is inferior in processability and mechanical properties. The vinyl bond content of the diene portion of this diene-based copolymer is usually 10 to 90%, preferably 20 to 8%.
0%, more preferably 25 to 75%, particularly preferably 3
It is 0 to 60%. When the vinyl bond content is less than 10% or more than 90%, the flexibility of the rubber composition in the low temperature region is lowered. The arrangement of the constituent component composed of the vinyl aromatic compound and the constituent component composed of the conjugated diene compound in this diene copolymer is random. When a hydrogenated copolymer of a random copolymer is used, a vulcanized product of a rubber composition having an excellent compression set is obtained as compared with the case of using a hydrogenated copolymer of a block copolymer. The diene-based random copolymer is obtained, for example, by performing anion living polymerization in a hydrocarbon solvent using an organolithium initiator. The branched polymer is usually 2 to
A coupling agent having a functionality of 6, preferably 3 to 4 is added in the required amount after the completion of the polymerization to perform coupling.

As the organic lithium initiator, n-butyllithium, sec-butyllithium, t-butyllithium and the like are used. As the hydrocarbon solvent, hexane,
Heptane, methylcyclopentane, cyclohexane, benzene, toluene, xylene, 2-methylbutene-1,
2-Methylbutene-2 or the like is used. The content of vinyl bonds such as 1,2-bonds and 3,4-bonds in the diene copolymer can be controlled when the vinyl aromatic compound and the conjugated diene compound are copolymerized using an organic alkali metal catalyst. The cocatalyst is an ether, a tertiary amine compound, an alkoxide of an alkali metal such as sodium or potassium, a phenoxide or a sulfonate.

Polymerization may be carried out batchwise or continuously,
The polymerization temperature is usually in the range of 0 to 120 ° C., and the polymerization time is 10
It is performed in the range of minutes to 3 hours. Examples of coupling agents include tetrachlorotin, butyltrichlorotin, tetrachlorogermanium, bis (trichlorosilyl) ethane, divinylbenzene, adipic acid diester, epoxidized liquid polybutadiene, epoxidized soybean oil, epoxidized linseed oil, tri Diisocyanate, 1,2,4-
Examples thereof include benzene triisocyanate. The hydrogenation reaction is carried out by dissolving the above-mentioned diene random copolymer in a hydrocarbon solvent, at 20 to 150 ° C., under pressurized hydrogen of 1 to 100 kg / cm 2, and in the presence of a hydrogenation catalyst.

As the hydrogenation catalyst, a catalyst in which a noble metal such as palladium, ruthenium, rhodium or platinum is supported on silica, carbon, diatomaceous earth, a complex catalyst such as ruthenium, rhodium or platinum, or an organic carboxylic acid such as cobalt or nickel is used. Organoaluminum or a catalyst composed of organolithium, titanium compounds such as dicyclopentadienyl titanium dichloride, dicyclopentadienyl diphenyl titanium, dicyclopentadienyl titanium ditolyl, dicyclopentadienyl titanium dibenzyl, and lithium, A hydrogenation catalyst made of an organometallic compound made of aluminum or magnesium is used. By hydrogenating the diene-based random copolymer thus polymerized, the hydrogenated diene-based copolymer (A) which is the rubber-like copolymer of the present invention is obtained.

The component (B) can be obtained by graft-copolymerizing a nitrile group-containing vinyl monomer and / or a --COO-bond-containing vinyl monomer with the above hydrogenated diene copolymer. . Here, the nitrile group-containing vinyl monomer and / or the -COO-bond-containing vinyl monomer 5 to 5 to 95% by weight of the hydrogenated diene polymer is used.
It is preferable to graft-copolymerize 50% by weight. The modified hydrogenated diene-based copolymer specified in the present invention,
(A) In addition to a graft copolymer obtained by graft-polymerizing a nitrile group-containing vinyl monomer and / or a —COO-bond-containing vinyl monomer on a hydrogenated diene-based copolymer,
It may be a mixture of a copolymer of a vinyl monomer containing a nitrile group and a vinyl monomer containing a -COO-bond and the graft copolymer.

Examples of the nitrile group-containing vinyl monomer include acrylonitrile and methacrylonitrile. Examples of —COO-bond-containing vinyl monomers include:
With alkyl group having 1 to 10 carbon atoms (meth) acrylic acid alkyl _{ester, CnH 2 n + 1 -O-} CmH 2 m- group (where n, m is an integer from 1 to 4) with (meth) acrylic acid There are alkyl esters, vinyl acetate, and (meth) acrylic acid, preferably methyl (meth) acrylate,
Examples thereof include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, methoxyethyl (meth) acrylate, and ethoxymethyl (meth) acrylate. Of these, methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate are more preferable, and specifically, (meth) acrylic acid-2
-Methoxyethyl and ethoxymethyl (meth) acrylate.

From these vinyl monomers containing a nitrile group and vinyl monomers containing a --COO-- bond, one kind or two or more kinds are arbitrarily selected in accordance with the balance of the oil resistance and cold resistance of the desired rubber. , Can be combined in any ratio. The composition ratio of the vinyl monomer is such that the nitrile group-containing vinyl monomer /-COO in all the polymerized vinyl monomers
-Constituents consisting of vinyl monomers containing bonds are 0 by weight.
-60 / 100-40 (wt%), preferably 10-5
It is in the range of 0/90 to 50 (% by weight).

By the graft copolymerization of these monomers, the glass transition point of the graft chain produced and the copolymer not grafted are not particularly limited,
When the content of the nitrile group-containing vinyl monomer is 60% by weight or more, the glass transition point becomes high and the cold resistance of the graft copolymer rubber is impaired. The content of the nitrile group-containing vinyl monomer and / or the carboxyl group-containing vinyl monomer contained in the modified hydrogenated diene-based copolymer of the present invention can be arbitrarily selected according to the purpose. However, in order to satisfy various physical properties such as mechanical properties and compression set of the rubber composition, the range is 5 to 50% by weight, preferably 5 to 4% by weight.
It is 0% by weight. If the content exceeds 50% by weight, only a graft copolymer rubber having a low viscosity can be obtained, and only a composition having poor processability and low physical properties can be obtained.

The graft ratio of the modified hydrogenated diene polymer thus obtained is usually 5% by weight or more. When the graft ratio is less than 5% by weight, the compatibility between the graft copolymer and the ungrafted copolymer is insufficient, and only poor processability and mechanical properties can be obtained. The method for producing the modified hydrogenated diene-based copolymer of the present invention comprises grafting a hydrogenated diene-based copolymer of a random copolymer with a nitrile group-containing vinyl monomer and / or a -COO-bond-containing monomer. To do. As the grafting method, any of solution grafting, melt grafting, aqueous suspension grafting, and radiation grafting can be adopted. For example, by solution grafting, the hydrogenated diene polymer is dissolved in an organic solvent in which both the hydrogenated diene copolymer of the random copolymer and the graft copolymer are soluble, for example, benzene, toluene, tetrahydrofuran (THF), etc. Then, after the monomer and the radical initiator are added, the temperature is raised to start and complete the polymerization. According to this method, the modified hydrogenated diene-based copolymer can be industrially easily obtained.

As the radical initiator, for example, benzoyl peroxide, lauroyl peroxide, t-
Examples thereof include organic peroxides such as butyl peroxylaurate, t-butyl peroxy acetate, t-butyl peroxy isopropyl carbonate, t-butyl peroxy benzoate. The amount of these radical initiators used is 0.05 per 100 parts by weight of the monomers used.
-30 parts by weight, preferably 0.1-20 parts by weight. In the solution graft polymerization, 1 part of the organic solvent is usually added to 100 parts by weight of the hydrogenated diene polymer and the total amount of the monomers.
The polymerization is carried out at a polymerization conversion rate of 30% or more, usually 50% or more under the conditions of a polymerization temperature of 50 to 120 ° C., using 0.00 to 1,000 parts by weight and a radical initiator in the above range.

The polymerized modified hydrogenated diene copolymer is
After removing unreacted monomers and organic solvent by ordinary steam distillation, the product is purified by drying. The nitrile-modified acrylate-based copolymer of the component (C) is
(Meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
It is a copolymer of a nitrile group-containing monomer and a (meth) acrylic acid derivative such as butyl (meth) acrylate, methoxyethyl (meth) acrylate, and ethoxymethyl (meth) acrylate.

Examples of the nitrile group-containing vinyl monomer include acrylonitrile and methacrylonitrile. The composition ratio of these vinyl monomers is 1 to 60% by weight, preferably 20 to 55% by weight, and more preferably 35 to 55% by weight in the nitrile group-containing vinyl monomer. The glass transition point of the copolymer produced by the copolymerization of these monomers is not particularly limited, but when the content of the nitrile component exceeds 60% by weight, the glass transition point becomes high and the rubber composition The cold resistance of is impaired. Furthermore, in order to facilitate the vulcanization of the rubber composition, methoxyethyl (meth) acrylate, (meth)
It is preferable to use an alkoxyalkyl acrylate such as ethoxymethyl acrylate, and the content of the alkoxyalkyl acrylate in the nitrile-modified acrylate copolymer is 5 to 60% by weight, preferably 20 to 55%.
If it is less than 5% by weight, vulcanization is unlikely to occur, and if it exceeds 60% by weight, heat resistance is poor.

The blending ratio of the component ((A) + (B)) and the component (C) in the present invention can be arbitrarily selected according to the purpose, but the mechanical properties of the rubber composition, compression set, etc. In order to satisfy the physical properties of, the range is such that the weight ratio of component ((A) + (B)): component (C) is 90:10.
When the content of the component (C) is less than 10% by weight, the oil resistance is poor, and when it exceeds 50% by weight, the mechanical strength is poor. The mixing ratio of component (A) and component (B) is 0: 1 by weight.
It can be compounded in any ratio from 00 to 100: 0, but a rubber composition comprising component (B) = 0, that is, component (A) and component (C) is preferable. When the component (B) is blended, it works as a compatibilizing agent for the component (A) and the component (C) and is excellent in kneading processability. The rubber composition of the present invention may contain an organic peroxide in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the rubber component in order to obtain a vulcanized product.

The organic peroxide used as the crosslinking agent is
It is usually used as a cross-linking agent for rubber, and for example, 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 and 2,2'-bis (t-butylperoxy) -p-diisopropylbenzene.

The amount of the organic peroxide compounded varies depending on the crosslinking agent used, but with respect to 100 parts by weight of rubber,
The amount is 0.5 to 10 parts by weight, preferably 1 to 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 obtained vulcanizate decreases.
When the rubber component is crosslinked, a bifunctional or higher functional vinyl monomer or the like 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, divinyl. Examples thereof include benzene, N, N′-methylenebisacrylamide, p-quinonedioxime, p, p′-dibenzoylquinonedioxime, triazinethiol, triallyl cyanurate, triallyl isocyanurate and bismaleimide.

The composition of the present invention comprises, for example, (A) hydrogenated diene-based copolymer and (B) modified diene-based copolymer,
(C) a nitrile-modified acrylate-based copolymer is obtained by a method of blending and kneading with a kneading machine such as a Banbury mixer, a kneader, or a two-roll mill,
The method of adding each component, the order of addition, the kneading method, and the kneading equipment are not particularly limited. Further, the addition / blending method and order of addition of the organic peroxide are not particularly limited, but it is preferable to add and blend the last in view of the storage stability of the rubber composition. A reinforcing filler can be added to the composition of the present invention, if necessary. This reinforcing filler not only has the advantage of being able to reduce the product cost as an extender, but also has a positive effect on the mechanical properties.

Examples of the reinforcing filler include fumed silica, wet silica, fine quartz powder, diatomaceous earth, talc,
Carbon black, zinc white, basic magnesium carbonate,
Examples include activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, mica powder, aluminum sulfate, calcium sulfate, barium sulfate, asbestos, glass fiber, organic reinforcing agent, and organic filler. The amount of these reinforcing fillers blended is 100 parts by weight of rubber,
It is from 0 to 200 parts by weight, preferably up to 100 parts by weight. If the amount exceeds 200 parts by weight, the kneading property and roll workability will be poor. 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 and castor. Oil, calcium stearate; Antiaging agents such as phenylenediamines, phosphates, quinolines, cresols, phenols, dithiocarbamate metal salts; Heat-resistant agents such as iron oxide, cerium oxide, potassium hydroxide,
Iron naphthenate, potassium naphthenate; other colorants,
An ultraviolet absorber, a flame retardant, an oil resistance improver, a foaming agent, an anti-scorch agent, a tackifier, a lubricant and the like can be optionally mixed.

The above additives may be added in the process of producing the rubber composition of the present invention, if necessary,
It may be added after the rubber composition is manufactured. The rubber composition of the present invention can be molded and vulcanized after kneading the above components to give a crosslinkable rubber composition. When vulcanizing this rubber composition, a crosslinking accelerator, if necessary,
A crosslinking aid, an acceleration aid, a crosslinking retarder and the like may be used in combination.
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, vulcanization is usually performed at 80 to 200 ° C. for several minutes to 3 hours under a pressure of ^{20 to} 200 kg / cm ² . Further, if necessary, secondary vulcanization is performed at 80 to 200 ° C. for 1 to 48 hours to obtain a product.

[0024]

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 hydrogenated diene-based copolymer] Synthesis of diene copolymer After charging 2,500 g of degassed and dehydrated cyclohexane, 150 g of styrene and 350 g of 1,3-butadiene in a 5 liter autoclave, 3.5 g of tetrahydrofuran and 0.33 g of n-butyllithium was added, polymerization was initiated at a polymerization temperature of 30 ° C., and temperature rising polymerization was performed until the temperature reached 80 ° C. After the polymerization conversion rate became almost 100%, 0.19 g of SiCl4 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 had a vinyl bond content of 30% and a styrene content of 30% by weight, and a branched polymer having three or more branches was 60% by weight. Number average molecular weight by GPC analysis is 27,000, M
w / Mn was 10.7.

The styrene-butadiene random copolymer synthesized by hydrogenation was charged into a 3 liter autoclave to prepare a 15% cyclohexane solution. After replacing the inside of the system with nitrogen, nickel naphthenate: n-butyllithium prepared beforehand in another container:
A catalyst solution of tetrahydrofuran = 1: 8: 20 (molar ratio) was charged so that the amount of nickel was 1 mol based on 2000 mol of the olefin portion. 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 coagulation, roll drying was carried out by a conventional method to obtain a hydrogenated diene copolymer having a hydrogenation rate of 98% (Moonie viscosity 82: ML1 + 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 Corp. 8
02A; carrier: 0.5 ml / min THF; polystyrene gel column: GPC-UT8 manufactured by Showa Denko KK
06L column; molecular weight: converted to polystyrene]. The hydrogenation rate (hydrogenation rate) was measured at a 15% concentration of 10
It was calculated from the decrease in the spectrum of the unsaturated bond portion of the 1 H-NMR spectrum at 0 MHz.

[Synthesis of modified hydrogenated diene polymer] A hydrogenated diene copolymer 60 produced by the above-described synthesis method was placed in a 1 liter separable flask equipped with a reflux condenser, a thermometer, a nitrogen inlet and a stirrer. By weight, the system was replaced with nitrogen. To this was added 500 parts by weight of degassed toluene, and the mixture was heated and dissolved under stirring, and then the monomer (acrylonitrile / 2-methoxyethyl acrylate = 20 /
20: parts by weight) and 1 part by weight of t-butylperoxyisopropyl carbonate as a radical initiator, the temperature was raised to 95 ° C., and the polymerization was carried out for 12 hours while controlling the polymerization temperature to a constant level to obtain a polymerization conversion rate of 74%. did. After completion of the polymerization, the reaction mixture was taken out of the separable flask, and toluene and unreacted monomers were removed by steam distillation. Next, the deposited rubbery polymer was vacuum dried to obtain a modified hydrogenated diene copolymer.

A certain amount of the modified hydrogenated diene-based copolymer thus obtained is put into methyl ethyl ketone in which the hydrogenated diene-based copolymer is insoluble, and 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.
It was 0% by weight. Furthermore, the composition of the obtained modified hydrogenated diene-based copolymer was determined by the following method. The ratio of the hydrogenated diene polymer in the total rubber was calculated from the polymerization conversion ratio, and the ratio of the monomers was calculated from the ratio of the spectrum of each component of the ¹³ C-NMR spectrum at 100 MHz. Hydrogenated diene polymer / acrylonitrile / 2-methoxyethyl acrylate = 67/16/17 (wt%)

[Synthesis of Nitrile-Modified Acrylate Copolymer] Synthesis Examples 1 to 4 100 parts by weight of the monomer mixture described in Table 1, Synthesis Example 1 column, 4 parts by weight of sodium lauryl sulfate, p-menthane hydroperoxide. 0.25 parts by weight, monoiron sulfate 0.0
1 part by weight, sodium ethylenediaminetetraacetate 0.02
5 parts by weight and 0.04 parts by weight of sodium formaldehyde sulfoxylate were charged into an autoclave substituted with nitrogen and reacted at a reaction temperature of 10 ° C. until the monomer conversion rate reached 90%, and N, N-diethylhydroxyl was added. The reaction was stopped by adding 0.5 part by weight of amine.

Next, the reaction mixture was taken out, and unreacted monomers were removed by steam distillation. The rubber latex thus obtained is coagulated by adding it to a 0.25% calcium chloride aqueous solution, and the coagulated product is thoroughly washed with water and then at about 90 ° C. for 2 hours.
A nitrile modified acrylate-based copolymer P-1 was obtained by drying for an hour. The composition of the nitrile-modified acrylate copolymer P was calculated from the chemical shift of the ¹³ C-NMR spectrum. Polymers P-2 to 4 were also synthesized by the same method.

[0031]

[Table 1]                             Synthesis Example 1 Synthesis Example 2 Synthesis Example 3 Synthesis Example 4 Polymer number P-1 P-2 P-3 P-4 Polymer composition (wt%) Methyl acrylate 25 Ethyl acrylate 16 100 n-butyl acrylate 44 2-Methoxyethyl acrylate 50 25 38 Acrylonitrile 50 50 2

[Production of Rubber Composition and Evaluation thereof] An example of producing the rubber composition of the present invention will be described. Examples 1 to 6, Comparative Examples 1 to 4 (A) Hydrogenated diene-based copolymer, (B) Modified hydrogenated diene-based copolymer, (C) Nitrile-modified acrylate-based copolymer (P-1 to P- -3) was kneaded and blended in a conventional manner with an internal mixer according to the blending ratio shown in Table 2 to produce each rubber composition. As a comparative example, the polymer P-4 synthesized in Synthesis Example 4 and chloroprene rubber / neoprene GRT (trade name, Du-Pont
Manufactured by Nippon Synthetic Rubber Co., Ltd., and FEF carbon black, SEAST SO (trade name, manufactured by Tokai Carbon Co., Ltd.), MAF carbon black Seast 116
(Trade name, manufactured by Tokai Carbon Co., Ltd.), as a rubber chemical component, organic peroxide, Percadox 14/40 (trade name, manufactured by Kayaku Akzo Co., Ltd.), zinc white, magnesium oxide, stearic acid Potassium, sodium stearate,
Cross-linking aid, Barnock P, with sulfur as other component
M (trade name, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) and stearic acid were used in the formulations shown in Table 2.

[0033]

[Table 2]

The initial physical properties, aging test, oil resistance, cold resistance and compression set of each rubber composition thus produced are J
It evaluated based on IS K6301 and the conditions shown below. The results are shown in Table 3. The conditions for vulcanization and evaluation of physical properties are as follows. (Vulcanization Conditions) Examples 1 to 5, Comparative Examples 1 and 2: Press vulcanization at 170 ° C. for 20 minutes. Comparative Example 3: 150 ° C. × 20 minutes press vulcanization. Comparative Example 4: After press vulcanization at 170 ° C. for 20 minutes, 175
Gear oven secondary vulcanization at ℃ × 4 hours. (Physical property evaluation conditions) Aging test: 150 ° C. × 168 hours Gear oven. Oil resistance: JIS # 3 oil is used, 100 ℃ × 7
Soak for 2 hours. Cold resistance: Low temperature torsion test. Compression set: 25% compression, 120 ° C x 72 hours gear oven.

[0035]

[Table 3]

From the results shown in Table 3, in Examples 1 to 5, the hydrogenated diene-based copolymer, the modified hydrogenated diene-based copolymer and the nitrile-modified acrylate-based copolymer were blended to mechanically It can be seen that a rubber composition having excellent properties, heat resistance, cold resistance and oil resistance can be obtained. Furthermore, in Example 6, it can be seen that by using the graft modified rubber, the kneading processability can be improved without impairing the physical properties of the vulcanized product. On the other hand, Comparative Examples 1 and 4 are examples in which acrylic rubber was used instead of the nitrile-modified acrylate copolymer, and the mechanical properties and oil resistance were poor. Comparative Example 2 is an example in which only hydrogenated styrene-butadiene random copolymer rubber was used as the rubber component, but the oil resistance was poor. Comparative Example 3 is a conventional oil resistant rubber (chloroprene rubber), which has oil resistance but is inferior in heat resistance.

[0037]

The present invention provides a novel oil resistant rubber composition obtained by blending a (modified) hydrogenated diene copolymer and a nitrile modified acrylate copolymer. According to the invention, mechanical properties, heat resistance, cold resistance,
A rubber and a rubber composition having excellent oil resistance and compression set can be obtained. Conventional oil-resistant rubber is inferior in physical property balance, and its use in applications where both oil resistance-heat resistance or oil resistance-mechanical properties are required has been limited,
The rubber and the rubber composition according to the present invention have an excellent balance, and it has become possible to develop applications that are limited in the conventional rubber. The rubber composition of the present invention is used for various belt materials such as toothed belts and V-ribbed belts, hose materials, gaskets, boots, electric cables,
Adhesives, coatings, industrial cloths, window glass sealing materials, automobile and industrial moldings and extrusions, shoes,
It can be widely applied to fields such as papermaking.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-41140 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 51/06 C08L 15/00 C08K 5 / 14 C08L 33/08

Claims (3)

(57) [Claims] 1. A hydrogenated part of a diene polymer of a random copolymer (A) comprising a vinyl aromatic compound and a conjugated diene compound is hydrogenated so that 50% or more of the olefinically unsaturated bond of the copolymer is hydrogenated. Hydrogenated diene-based copolymer,
(B) A modified hydrogenated diene-based copolymer obtained by graft-copolymerizing the hydrogenated diene-based copolymer with a nitrile group-containing vinyl monomer and / or a -COO-bond-containing vinyl monomer, (C) contains a nitrile-modified acrylate copolymer and a cross-linking agent, and the mixing ratio of the components ((A) + (B)) and the component (C) is 90:10 to 50:50 by weight, and The rubber composition, wherein the compounding ratio of the component (A) and the component (B) is a weight ratio of 0: 100 to 100: 0. 2. The cross-linking agent is an organic peroxide, and
One, the rubber component ((A) + (B) + (C)) 100 parts by weight of mixing ratio of said organic peroxide is 0.5 to 1
The rubber composition according to claim 1, which is 0 part by weight. 3. The rubber composition according to claim 1 or 2 is crosslinked.
A rubber characterized by being formed .