JPH09124847A - Rubber composition comprising highly saturated nitrile group containing copolymer rubber and ethylene-alpha-olefin copolymer rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition excellent in heat resistance and permanent compression set properties, etc., useful for rubber products for various sealings by vulcanizing a mixture of a nitrile group containing highly saturated copolymer rubber and an ethylene-propylene rubber with an organic peroxide. SOLUTION: This composition is obtained by compounding (A) a nitrile containing highly saturated rubber produced by hydrogenating the conjugated diene part of an unsaturated nitrile-conjugated diene-unsaturated discarboxylic acid ester copolymer and (B) an ethylene-α-olefin copolymer rubber and (C) an organic peroxide vulcanizer. The composition contains 95-20wt.%, preferably 70-50wt.% of component (A) and 5-80wt.%, preferably 30-50wt.% of component (B), and the component (C) is preferably used within the range of 0.1-15 pts.wt per 100 pts.wt. of conjugated diene rubber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vulcanizable rubber composition containing a nitrile group-containing highly saturated copolymer rubber and an ethylene-saturated copolymer rubber.

[0002]

2. Description of the Related Art Several rubber compositions containing a nitrile group-containing highly saturated copolymer rubber and an ethylene-saturated copolymer rubber are known. For example, JP-A-61
In Japanese Patent No. 283639, it is reported that the workability of ethylene-propylene rubber is improved by blending hydrogenated acrylonitrile-butadiene rubber at a maximum of about 30% by weight.

Alternatively, in Japanese Patent Laid-Open No. 61-40342, a nitrile group-containing highly saturated copolymer rubber obtained by hydrogenating a nitrile group-containing elastomer obtained by copolymerizing acrylic acid, an alkyl acrylate or the like, and an ethylene-propylene rubber. It has been reported that a homogeneous co-vulcanizate obtained by vulcanizing a mixture of the above with an organic peroxide vulcanizing agent can be obtained.

Further, the applicant has already disclosed in JP-A-58-403.
In JP-A No. 32, a partially hydrogenated unsaturated nitrile-conjugated diene obtained by hydrogenating an unsaturated nitrile-conjugated diene copolymer rubber obtained by copolymerizing an unsaturated carboxylic acid, an unsaturated carboxylic acid ester, N-methylolacrylamide or the like. Vulcanize a mixture of a system copolymer rubber and an ethylene-propylene-non-conjugated diene terpolymer rubber with a sulfur vulcanizing agent containing a thiuram vulcanization accelerator or a dithiocarbamate vulcanization accelerator. By doing so, it was reported that a rubber material excellent in oil resistance and the like can be obtained.

However, in recent years, rubber materials for automobile parts and the like have an excellent balance of oil resistance, heat resistance, weather resistance, cold resistance, etc. in a wide range of environments from low temperature to high temperature, and especially compression permanent. It is required that the distortion is not deteriorated, and further improvement has been desired.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rubber material having an excellent balance of oil resistance, heat resistance, weather resistance, cold resistance and the like, and improved compression set. Therefore, as a result of intensive studies, the present inventors have found that a nitrile group-containing highly saturated copolymer rubber obtained by hydrogenating an unsaturated nitrile-conjugated diene copolymer rubber obtained by copolymerizing an unsaturated dicarboxylic acid ester with ethylene-propylene. It was found that by vulcanizing a mixture with a system rubber with an organic peroxide, a rubber material excellent in cold resistance can be obtained,
The present invention has been completed based on this finding.

[0007]

Thus, according to the present invention, a nitrile group-containing highly saturated copolymer rubber obtained by hydrogenating a conjugated diene portion of an unsaturated nitrile-conjugated diene-unsaturated dicarboxylic acid ester copolymer, and Provided is a vulcanizable rubber composition prepared by blending an ethylene-α-olefin-based copolymer rubber and an organic peroxide-based vulcanizing agent.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The nitrile group-containing highly saturated copolymer rubber used in the present invention is an unsaturated nitrile-conjugated diene-
It is obtained by hydrogenating a conjugated diene portion of an unsaturated dicarboxylic acid ester copolymer and has a Mooney viscosity of 15 to
The iodine value is 200, preferably 30 to 100, and the iodine value is 80 or less, preferably 40 or less. When the Mooney viscosity is less than 15, only a molded product having low strength can be obtained, which is not preferable. If it exceeds 200, the viscosity increases and molding becomes difficult. The lower limit of the iodine value is at least 1. If the iodine value is too low, vulcanization becomes difficult.

The content of bonded unsaturated nitrile unit in the copolymer is 10 to 40% by weight, and particularly preferably 15 to 30% by weight.

Specific examples of unsaturated nitriles include acrylonitrile, methacrylonitrile and α-chloroacrylonitrile. Of these, acrylonitrile is preferred.

Specific examples of the conjugated diene include 1,3-butadiene, 2,3-dimethylbutadiene, isoprene,
1,3-pentadiene and the like can be mentioned. Above all,
1,3-butadiene is preferred.

Specific examples of the unsaturated dicarboxylic acid ester include monomethyl maleate, monoethyl maleate,
Monopropyl maleate, mono-n-butyl maleate, monoisobutyl maleate, mono-n-maleate
Pentyl, mono-n-hexyl maleate, mono-2-ethylhexyl maleate, monomethyl fumarate, monoethyl fumarate, monopropyl fumarate, mono-n-butyl fumarate, monoisobutyl fumarate, mono-n-fumarate. Pentyl, mono-n-hexyl fumarate, mono-2-ethylhexyl fumarate, monomethyl itaconate,
Monoethyl itaconate, monopropyl itaconate, mono-n-butyl itaconate, monoisobutyl itaconate,
Itaconic acid mono-n-pentyl, Itaconic acid mono-n-
Hexyl, mono-2-ethylhexyl itaconate, monomethyl citracone, monoethyl citracone, monopropyl citracone, mono-n-butyl citracone,
Citraconic acid monoisobutyl, citraconic acid mono-n-
Pentyl, mono-n-hexyl citracone, mono-2-ethylhexyl citracone, monomethyl mesaconate, monoethyl mesaconate, monopropyl mesaconate,
Mono-n-butyl mesaconate, monoisobutyl mesaconate, mono-n-pentyl mesaconate, mono-mesaconate
n-hexyl, mono-2-ethylhexyl mesaconate,
Monomethyl glutaconate, monoethyl glutaconate, monopropyl glutaconate, mono-n-butyl glutaconate, monoisobutyl glutaconate, mono-glutaconate
n-Pentyl, mono-n-hexyl glutaconate, mono-2-ethylhexyl glutaconate, monomethyl allyl malonate, monoethyl allyl malonate, monopropyl allyl malonate, mono-n-butyl allyl malonate, monoisobutyl allyl malonate, mono allyl malonate- n-
Pentyl, mono-n-hexyl allyl malonate, mono-2-ethylhexyl allyl malonate, monomethyl teraconate, monoethyl teraconate, monopropyl teraconate, mono-n-butyl teraconate, monoisobutyl teraconate, mono-n-teraconic acid Unsaturated dicarboxylic acid monoalkyl esters such as pentyl, mono-n-hexyl teraconate and mono-2-ethylhexyl teraconate.

Further, dimethyl maleate, diethyl maleate, dipropyl maleate, di-n-maleate.
Butyl, diisobutyl maleate, di-n-maleate
Pentyl, di-n-hexyl maleate, di-2-ethylhexyl maleate, dimethyl fumarate, diethyl fumarate, dipropyl fumarate, di-n-butyl fumarate, diisobutyl fumarate, di-n-pentyl fumarate, Di-n-hexyl fumarate, di-2-ethylhexyl fumarate, dimethyl itaconate, diethyl itaconate, dipropyl itaconate, di-n-butyl itaconate, diisobutyl itaconate, di-n-pentyl itaconate, itaconic acid Di-n-hexyl, itaconic acid di-2
-Ethylhexyl, dimethyl citraconic acid, diethyl citraconic acid, dipropyl citraconic acid, di-n-butyl citraconic acid, diisobutyl citraconic acid, di-n-pentyl citraconic acid, di-n-hexyl citraconic acid,
Di-2-ethylhexyl citraconic acid, dimethyl mesaconate, diethyl mesaconate, dipropyl mesaconate, di-n-butyl mesaconate, diisobutyl mesaconate, di-n-pentyl mesaconate, di-n-hexyl mesaconate, mesaconic acid Di-2-ethylhexyl, dimethyl glutaconate, diethyl glutaconate, dipropyl glutaconate, di-n-butyl glutaconate, diisobutyl glutaconate, di-n-pentyl glutaconate, di-n-hexyl glutaconate, di-glutaconate 2-ethylhexyl, dimethyl allylmalonate, diethyl allylmalonate, dipropyl allylmalonate, di-n allylmalonate
-Butyl, diisobutyl allylmalonate, di-n-pentyl allylmalonate, di-n-hexyl allylmalonate, di-2-ethylhexyl allylmalonate, dimethyl terraconate, diethyl terraconate, dipropyl terraconate, di-n-butyl terraconate , Diisobutyl terraconate, di-n-pentyl terraconate, di-n-terraconate
Examples include unsaturated dicarboxylic acid dialkyl esters such as hexyl and di-2-ethylhexyl teraconic acid.

By copolymerizing these unsaturated dicarboxylic acid ester type monomers with unsaturated nitriles and conjugated dienes, the nitrile group-containing highly saturated copolymer rubber used in the present invention has oil resistance, heat resistance, and A good balance of weather resistance and cold resistance can be achieved.

Among unsaturated dicarboxylic acid ester monomers, it is an ester of an unsaturated dicarboxylic acid having 4 to 6 carbon atoms and having 1 to 5 carbon atoms, preferably 2 to
Unsaturated dicarboxylic acid dialkyl esters having 4 alkyl groups are preferred. The amount of the unsaturated dicarboxylic acid ester-based monomer used is 1 to 80% by weight, preferably 15 to 60% by weight, more preferably 20 to 40% by weight based on the total amount of the monomers.
It can be used in the range of weight%.

In addition to these monomers, a part of all the monomers may be replaced with another copolymerizable monomer, if necessary, as long as the effects obtained by the present invention are not impaired. It is possible. Other copolymerizable monomers include vinyl-based monomers such as styrene, α-methylstyrene and vinylpyridine; non-conjugated diene-based monomers such as vinylnorbornene, dicyclopentadiene and 1,4-hexadiene. Fluoroethyl vinyl ether, fluoropropyl vinyl ether, trifluoromethyl vinyl ether,
Fluoroalkyl vinyl ethers such as trifluoroethyl vinyl ether, perfluoropropyl vinyl ether and perfluorohexyl vinyl ether, and fluorine-containing vinyl-based monomers such as o- or p-trifluoromethylstyrene, vinyl pentafluorobenzoate, difluoroethylene and tetrafluoroethylene Body; Furthermore, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate and the like can be mentioned.

Further, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isononyl acrylate, n-hexyl acrylate, 2-methyl-pentyl acrylate, n- Acrylates and methacrylates having an alkyl group having about 1 to 18 carbon atoms such as octyl acrylate, 2-ethylhexyl acrylate, n-dodecyl acrylate, methyl methacrylate, and ethyl methacrylate.

An acrylate having an alkoxyalkyl group having about 2 to 12 carbon atoms such as methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, ethoxypropyl acrylate, methoxyethoxy acrylate, and ethoxybutoxy acrylate.

Α and β-cyanoethyl acrylate,
An acrylate having a cyanoalkyl group having about 2 to 12 carbon atoms such as α, β and γ-cyanopropyl acrylate, cyanobutyl acrylate, cyanohexyl acrylate, and cyanooctyl acrylate.

Acrylate having a hydroxyalkyl group such as 2-hydroxyethyl acrylate and hydroxypropyl acrylate; dimethylaminomethyl acrylate, diethylaminoethyl acrylate, 3- (diethylamino) -2-hydroxypropyl acrylate, 2,3-bis (difluoroamino) ) Unsaturated carboxylic acid ester type monomers such as propyl acrylate.

Trifluoroethyl acrylate, tetrafluoropropyl acrylate, pentafluoropropyl acrylate, heptafluorobutyl acrylate,
Octafluoropentyl acrylate, nonafluoropentyl acrylate, undecafluorohexyl acrylate, pentadecafluorooctyl acrylate, heptadecafluorononyl acrylate, heptadecafluorodecyl acrylate, nonadecafluorodecyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, Acrylates and methacrylates having a fluoroalkyl group such as octafluoropentyl methacrylate, dodecafluoroheptyl methacrylate, pentadecafluorooctyl acrylate, and hexadecafluorononyl methacrylate.

Fluorine-substituted benzyl acrylates such as fluorobenzyl acrylate, fluorobenzyl methacrylate and difluorobenzyl methacrylate, and methacrylates can also be copolymerized.

The method for hydrogenating the unsaturated nitrile-conjugated diene-unsaturated dicarboxylic acid ester copolymer is not particularly limited, and it can be hydrogenated according to a conventional method. Examples of the catalyst used in the hydrogenation include palladium / silica and palladium complex (JP-A-3-252405). Furthermore, JP-A-62-125858, JP-A-62-42937,
Rhodium or ruthenium compounds such as those described in JP-A-1-45402, JP-A-1-45403, JP-A-1-45404, and JP-A-1-45405 can also be used.

The nitrile group-containing highly saturated copolymer rubber used in the present invention can also be obtained by a method of directly hydrogenating a latex of an unsaturated nitrile-conjugated diene-unsaturated carboxylic acid ester copolymer. As a method for direct hydrogenation, a method using a palladium catalyst (for example, JP-A-2-178305) and a method using a rhodium catalyst (for example, JP-A-59-115303 and JP-A-56-133219) are used. No. 3,898,2
08) and a method using a ruthenium-based catalyst (for example, JP-A-6-184223 and JP-A-6-1923).
No. 23) and the like, but are not limited thereto. As a specific example, when a palladium-based catalyst is used, an organic solvent that dissolves or swells a nitrile group-containing unsaturated copolymer is used as described in JP-A-2-178305. It is added to the latex. According to this method, the nitrile group-containing unsaturated copolymer in the copolymer latex swells with an organic solvent, and the hydrogenation catalyst can be easily accessible to the double bond in the copolymer, so that the aqueous solution The hydrogenation reaction can be efficiently performed while maintaining the emulsion state.

Specific examples of the palladium compound include, for example, palladium salts of carboxylic acids such as formic acid, acetic acid, propionic acid, lauric acid, succinic acid, stearic acid, oleic acid, phthalic acid and benzoic acid; palladium chloride, dichloro ( Chlorinated palladium such as cyclooctadiene) palladium, dichloro (norbornadiene) palladium, dichloro (benzonitrile) palladium, dichlorobis (triphenylphosphine) palladium, ammonium tetrachloropalladium (II) and ammonium hexachloropalladium (IV); Palladium bromide;
Examples thereof include inorganic compounds and complex salts such as palladium iodide; palladium sulfate dihydrate; potassium tetracyanopalladium (II) trihydrate; and the like, but are not limited thereto. Among them, palladium salts of carboxylic acids, dichloro (norbornadiene) palladium, ammonium hexachloropalladate and the like are particularly preferable.

The ethylene-α-olefin copolymer rubber used in the present invention is a copolymer of ethylene, α-olefin and non-conjugated diene and is a substantially saturated copolymer rubber. A typical example is ethylene-propylene-
Ethylene and C3-C14 such as non-conjugated diene terpolymer or multi-polymer rubber, ethylene-propylene-1-butene-non-conjugated diene copolymer rubber, ethylene-1-butene-non-conjugated diene multi-polymer rubber A low crystallinity or amorphous elastomer having an α-olefin as a main component and having a crystallinity of 20% or less, preferably 10% or less, or a mixture thereof. Among them, ethylene-propylene-non-conjugated diene terpolymer rubber is preferable.

Here, as the non-conjugated diene, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylenenorbornene, 5-ethylidene-2-norbornene and the like are used. Of these, dicyclopentadiene and 5 -A copolymer containing ethylidene-2-norbornene as a third component is preferable. The ethylene-α-
The Mooney viscosity [ML _{1 + 4} (100 ° C.)] of the olefin-non-conjugated diene copolymer rubber is usually 10 to 180, preferably 40 to 140, and its iodine value unsaturation is preferably 20. It is the following.

In these ethylene-α-olefin-non-conjugated diene copolymer rubbers, the ethylene unit / α-olefin unit is 50/50 to 90/10, preferably 60 /.
The ratio is 40 to 84/16 (molar ratio), and the (ethylene + α-olefin) unit / non-conjugated diene unit (in the case of a ternary or multi-component copolymer) is usually 98/2 to 90/1.
0, preferably 97/3 to 94/6 (molar ratio).

The mixing ratio of the nitrile group-containing highly saturated copolymer rubber and the ethylene-α-olefin copolymer rubber is
Usually, 95 to 20% by weight, preferably 70 to 50% by weight, of a nitrile group-containing highly saturated copolymer rubber and ethylene-
The content of the α-olefin copolymer rubber is 5 to 80% by weight, preferably 30 to 50% by weight. If the relative proportion of the nitrile group-containing highly saturated copolymer rubber is excessively large, the weather resistance decreases, and if the relative proportion of the ethylene-α-olefin copolymer rubber is excessively large, the oil resistance decreases.

The method of blending the nitrile group-containing highly saturated copolymer rubber and the ethylene-α-olefin copolymer rubber is not particularly limited, but usually, the nitrile group-containing highly saturated copolymer rubber and the ethylene-α-olefin rubber are blended. A dry blending method of mixing the olefin-based copolymer rubber with a Banbury mixer at a high temperature, or mixing the nitrile group-containing highly saturated copolymer rubber and the ethylene-α-olefin-based copolymer rubber in a latex state For example, a latex coprecipitation method in which the coagulation and drying are followed by a heat treatment using an extruder or a Banbury mixer is adopted.

The organic peroxide-based vulcanizing agent used in the present invention is not particularly limited as long as it can be used in ordinary rubber peroxide vulcanization. Examples include dicumyl peroxide, di-t-butyl peroxide, t-
Butyl cumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (benzoylperoxy) hexine, α , Α′-bis (t-butylperoxy-m-isopropyl) benzene and the like. Of these, di-t-butyl peroxide is preferable. These organic peroxides are used in the range of 0.1 to 15 parts by weight based on 100 parts by weight of the copolymer rubber.

Further, examples of the cross-linking aid include unsaturated compounds used in ordinary organic peroxide vulcanization. Examples thereof include ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, polyfunctional methacrylate monomers, N, N'-m-phenylenedimaleimide, triallyl isocyanurate and the like. Of these, triallyl isocyanurate is preferable from the viewpoint of vulcanization properties. These rubbers are added in an amount of the copolymer rubber 10
It is in the range of 0.1 to 15 parts by weight with respect to 0 parts by weight.

In the present invention, it is necessary to use an organic peroxide type vulcanizing agent as the vulcanizing material. When, for example, a sulfur-based vulcanizing agent other than the organic peroxide-based vulcanizing agent is used, it is difficult to obtain a rubber material having particularly excellent compression set resistance.

In the vulcanizable rubber composition of the present invention, if necessary, other conventional compounding agents used in the rubber field, such as a reinforcing agent (various carbon black, silica, talc, etc.), Fillers (calcium carbonate, clay, etc.), processing aids, process oils (plasticizers), antioxidants, antiozonants and the like can be added.

In the vulcanizable rubber composition of the present invention, if necessary, acrylic rubber, fluororubber, acrylonitrile-butadiene rubber, styrene-butadiene copolymer rubber,
Other rubbers such as natural rubber and polyisoprene rubber and ethylene-vinyl acetate copolymer resin can be used in combination.

The method for producing the vulcanizable rubber composition of the present invention is not particularly limited, but normally, a raw rubber and a vulcanizing system and other compounding ingredients are kneaded and mixed by a mixer such as a roll or a Banbury mixer. Thereby producing the rubber composition.

[0037]

The present invention will be described more specifically with reference to the following examples. Parts and% in Examples, Comparative Examples and Reference Examples are based on weight unless otherwise specified. The characteristics of the rubber composition and the raw material components were measured as follows. (1) Vulcanized physical property evaluation test According to Japanese Industrial Standard JIS K6301, an unvulcanized rubber composition prepared according to the compounding recipe of Table 1 was 170 ° C x 30
3mm sheet obtained by vulcanization under the conditions of
A test piece was punched out using a No. Bendal to measure tensile strength (unit: kgf / cm ² ), 100% tensile stress (unit: kgf / cm ² ) and elongation (unit:%). The hardness was measured using a JIS spring type A hardness tester. Furthermore, compression set is JIS
According to K6301, measurement was performed for a case of holding at 150 ° C. for 77 hours and a case of holding at −20 ° C. for 8 hours (unit:%).

(2) Oil resistance test According to JIS K6301, lubricating oil No. The rubber test piece was immersed in 3 (150 ° C., 72 hours), and the volume change rate (unit:%) was measured.

(3) Cold Resistance Test According to JIS K6301, the Gehman twist test was used for evaluation. When the twist angle is low (23 ℃), the twist angle is 10
It is indicated by the temperature (TR10) when it is doubled (unit: ° C). The lower the temperature, the better the cold resistance.

(4) Ozone resistance (weather resistance) According to JIS K6301, after static 20% elongation at an ozone concentration of 50 ppm and a temperature of 40 ° C., 12 hours, 24 hours,
After standing for 48 hours and 72 hours, the crack generation state was observed.

(Examples 1 to 16 and Comparative Examples 1 to 16) Table 1
Nitrile group-containing highly saturated copolymer rubber having unsaturated dicarboxylic acid ester units (HNBR1 to 4,
8-11) and ethylene-α-olefin copolymer rubber (EPDM1, 2) were mixed in the proportions (% by weight) shown in Tables 3-4, and an organic peroxide vulcanizing agent was added thereto. An evaluation test was conducted on the vulcanizable rubber composition, and the results are shown in Table 7-
The results are shown in FIG. For comparison, the nitrile group-containing highly saturated copolymer rubber (HNBR5-7, 12-14) having an unsaturated monocarboxylic acid ester unit and the ethylene-α-olefin copolymer rubber (EPDM1, 2) were similarly treated. An evaluation test was conducted on the vulcanizable rubber composition, and the results are shown in Tables 7-10. HNBR 7 and 14 are highly saturated copolymer rubbers obtained by hydrogenating a binary copolymer of acrylonitrile and butadiene, and the same evaluation tests as above were carried out for these, and the results are shown in Tables 7 to 7. It is also shown in 10.

The compounding formulation of the vulcanizable rubber composition (Examples 1 to 16 and Comparative Examples 1 to 12) is as follows. Copolymer rubber mixture 100 parts FT carbon black 60 parts ISAF carbon black 50 parts trimellitic acid ester plasticizer 30 parts 2-mercaptobenzimidazole zinc salt 1.5 parts substituted diphenylamine 1.5 parts 1,3-bis (No. 3-Butylperoxyisopropyl) benzene 8 parts

The following were used as the ethylene-α-olefin copolymer rubber. (1) Ethylene-propylene-dicyclopentadiene copolymer ethylene / propylene / dicyclopentadiene = 55 /
40/5 (molar ratio) (hereinafter referred to as EPDM1) Mooney viscosity 80 (2) ethylene-propylene-ethylidene norbornene copolymer styrene / propylene / ethylidene norbornene = 60
/ 35/5 (molar ratio) (hereinafter referred to as EPDM2) Mooney viscosity 85

As a comparison, for the experiment numbers 4, 7, 12 and 15 in the mixing ratio of HNBR and EPDM, evaluation tests were also conducted for those containing a sulfur-based vulcanizing agent. The compounding recipe (Comparative Examples 13 to 16) is as follows. The results are shown in Table 11.

Copolymer rubber mixture 100 parts FT carbon black 60 parts ISAF carbon black 50 parts trimellitic acid ester plasticizer 30 parts 2-mercaptobenzimidazole zinc salt 1.5 parts zinc white 5 parts stearic acid 1 part sulfur 0 .5 parts Tetramethylthiuram disulfide 1.5 parts 2-mercaptobenzothiazole 0.5 parts

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[0050]

[Table 5]

[0051]

[Table 6]

[0052]

[Table 7]

[0053]

[Table 8]

[0054]

[Table 9]

[0055]

[Table 10]

[0056]

[Table 11]

From the results of Tables 7 to 11, the vulcanizate obtained by vulcanizing the rubber composition of the present invention has a cold resistance, compared with the copolymer rubber having an unsaturated monocarboxylic acid ester unit. Excellent balance of oil resistance and weather resistance, as well as heat resistance,
It can be seen that the compression set is improved.

In particular, from the results of Tables 7 and 9, experimental examples using a copolymer of unsaturated dicarboxylic acid dialkyl ester monomers as the nitrile group-containing highly saturated copolymer rubber (Examples 1 to 5, 9 to 13), in comparison with an example (Comparative Examples 1, 2, 7, 8) using a copolymer of unsaturated dicarboxylic acid monoalkyl ester-based monomers,
Tensile strength and 100% tensile stress increase, low temperature (-
Compression set resistance and cold resistance (TR1) at 20 ° C
0) is shown to be good.

Further, from Table 11, Experiment Nos. 4, 7, 12
When the sulfur-based vulcanizing agent was added to the rubber mixtures of Nos. 15 and 15, the 100% tensile stress was lowered, and the compression set resistance (150 ° C) was shown to be insufficient.

[0060]

The vulcanizate obtained by vulcanizing the rubber composition of the present invention has an excellent balance of cold resistance, oil resistance and weather resistance, and at the same time has improved heat resistance and compression set. It is effective when used in rubber parts that come into contact with gas, etc. and require cold resistance and oil resistance. Therefore, the vulcanizable rubber composition of the present invention is used for various sealing rubber products such as O-rings, packings and gaskets; various belts such as conveyor belts, V-belts and timing belts; bubbles and bubble sheets, BOP (Blow out). preven
tar), pladers, etc .; various cushioning materials, anti-vibration materials, etc .;
It can be widely used for manufacturing various hoses such as oil-based hoses, marine hoses, risers and flow lines.

A concrete embodiment of claim 1 of the present invention is as follows. (1) 95 to 20% by weight of a nitrile group-containing highly saturated copolymer rubber obtained by hydrogenating a conjugated diene portion of an unsaturated nitrile-conjugated diene-unsaturated dicarboxylic acid ester copolymer and ethylene-α-olefin copolymer A vulcanizable rubber composition obtained by mixing 0.1 to 15 parts by weight of an organic peroxide-based vulcanizing agent with 100 parts by weight of a rubber mixture containing 5 to 80% by weight of a united rubber. (2) The vulcanizable rubber composition according to (1), wherein the unsaturated nitrile is selected from acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. (3) The vulcanizable rubber composition of (1), wherein the conjugated diene is selected from 1,3-butadiene, 2,3-dimethylbutadiene, isoprene, 1,3-pentadiene and the like. (4) The vulcanizable rubber composition according to (1), wherein the unsaturated dicarboxylic acid ester is an unsaturated dicarboxylic acid dialkyl ester. (5) The vulcanizable rubber composition of (1), wherein the nitrile group-containing highly saturated copolymer rubber has 10 to 40% by weight of an unsaturated nitrile unit and 1 to 80% by weight of an unsaturated dicarboxylic acid ester unit. . (6) The vulcanizable rubber composition of (1), wherein the unsaturated nitrile is acrylonitrile and the conjugated diene is 1,3-butadiene. (7) The vulcanizable rubber composition of (1), wherein the nitrile group-containing highly saturated copolymer rubber has an iodine value of 80 or less and a Mooney viscosity of 15 to 200. (6) Vulcanization of (1), wherein the ethylene-α-olefin-based copolymer rubber is a copolymer of ethylene, α-olefin and non-conjugated diene and is a substantially saturated copolymer rubber. Rubber composition. (7) The ethylene-α-olefin copolymer rubber is an ethylene-propylene-non-conjugated diene ternary or multi-component polymer rubber, ethylene-propylene-1-butene-non-conjugated diene copolymer rubber, ethylene-1- Ethene such as butene-non-conjugated diene multipolymer rubber and α having 3 to 14 carbon atoms
(1) A vulcanizable rubber composition which is a low crystallinity or amorphous elastomer containing olefin as a main component and having a crystallinity of 20% or less, preferably 10% or less, or a mixture thereof. (8) The non-conjugated diene of the ethylene-α-olefin-non-conjugated diene copolymer rubber is dicyclopentadiene,
1,4-hexadiene, cyclooctadiene, methyl
The vulcanizable rubber composition is selected from dennorbornene, 5-ethylidene-2-norbornene, and the like. (9) The vulcanizable rubber composition according to (1), wherein the ethylene-α-olefin copolymer rubber has a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 10 to 180 and an iodine value of 20 or less. (10) The ethylene-α-olefin-non-conjugated diene copolymer rubber has an ethylene unit / α-olefin unit of 50.
/ 50 to 90/10 (molar ratio), and the ratio of (ethylene + α-olefin) unit / non-conjugated diene unit (in the case of a ternary or multicomponent copolymer) is 98/2 to 90/10.
(1) The vulcanizable rubber composition having a (molar ratio).

Claims (1)

[Claims] 1. A nitrile group-containing highly saturated copolymer rubber obtained by hydrogenating the conjugated diene portion of an unsaturated nitrile-conjugated diene-unsaturated dicarboxylic acid ester copolymer, and an ethylene-α-olefin copolymer rubber, and A vulcanizable rubber composition containing an organic peroxide vulcanizing agent.