WO1998044035A1

WO1998044035A1 - Rubber composition

Info

Publication number: WO1998044035A1
Application number: PCT/JP1998/001261
Authority: WO
Inventors: Yoshinori Fujii
Original assignee: Nippon Zeon Co., Ltd.
Priority date: 1997-03-28
Filing date: 1998-03-24
Publication date: 1998-10-08

Abstract

A rubber composition having not only oil resistance, heat resistance, and wearing resistance but high tensile strength and high tensile stress; and a modifier for preparing the same. By way of example, a modifier which comprises a carboxylated, highly saturated copolymer rubber containing nitrile groups and has an acid equivalent of 1.63x10-2 ephr, a value of the ratio of the height of the peak assignable to the carboxylic anhydride group to the sum of the height of the peak assignable to the carboxylic anhydride group and the height of the peak assignable to the carboxyl group in infrared absorption spectromety of 0.96, a Mooney viscosity of 65, an iodine value of 28, and a methly-ethyl-ketone-insolubles content of 0.2 % is prepared by masticating a highly saturated polymer rubber containing nitrile groups with a pressure kneader (capacity: 75 liters; MS type), introducing 1.8 parts by weight of maleic anhydride and 0.5 parts by weight of 2,6-di-tert-butyl-4-methylphenol (BHT) into the pressure kneader after the rubber temperature has reached 130 °C, continuously kneading the resultant mixture (prekneading) so as to regulate the rubber temperature to 250 °C by utilizing the heat of shearing generated by kneading, and further kneading the mixture at that temperature for 15 minutes to cause the rubber to undergo an ene-addition reaction. Incorporating this modifier into a polyether rubber serves to give the objective rubber composition having the aforementioned properties.

Description

Specification

Rubber composition

Technical field

The present invention relates to a rubber composition and a rubber strength modifier. More specifically, the present invention provides a rubber composition having improved tensile strength and tensile stress, and having excellent heat resistance, oil resistance, and low abrasion resistance, and a rubber strength modification for obtaining the rubber composition. About the agent.

Background art

BACKGROUND ART A highly saturated conjugated diene polymer rubber containing a ditolyl group obtained by adding hydrogen to a carbon-carbon double bond in an ethylenically unsaturated ditolyl-conjugated gen copolymer is known. This nitrile group-containing highly saturated conjugated polymer rubber is used as another rubber, for example, silicone rubber, acrylonitrile-butadiene rubber, fluorine rubber, acryl rubber, hydrin rubber, ethylene-propylene rubber, ethylene-propylene-gene rubber. It has been proposed to improve the oil resistance, heat resistance, low abrasion, etc. of these other rubbers by mixing them with polyester rubber, polyurethane rubber, chloroprene rubber and the like. These rubber compositions having improved oil resistance and the like (Japanese Patent Application Laid-Open Nos. 60-141, 39-39, 61-625, 38-68, and 6-26-39 23, Japanese Patent Application Laid-Open No. 8-100082) is used for sealing materials, rolls, belts, hoses, tubes, and the like.

However, since the nitrile group-containing highly saturated conjugated polymer rubber has low compatibility with other rubbers, the rubber composition containing the nitrile group-containing highly saturated conjugated polymer rubber and the other rubber has a tensile strength. It does not yet have satisfactory properties such as strength and tensile stress. An object of the present invention is to provide a rubber composition having high tensile strength and high tensile stress in addition to oil resistance, heat resistance and wear resistance, and a modifier for obtaining the same.

The present inventors have conducted intensive studies to achieve the above object, and as a result, using a specific carboxylated nitrile group-containing highly saturated copolymer rubber as a modifier, a heat-resistant rubber, particularly a nitrile group highly saturated copolymer. It has been found that the above object can be achieved by compounding the rubber, and the present invention has been completed based on this finding.

Disclosure of the invention

Thus, according to the present invention,

(1) an acid equivalent of 1 X 10- ⁴ ephr above, arm one knee viscosity _{(ML 1+ 4, 1 00 °} C) is 15 to 200 and carboxylation of 80 or less iodine value two preparative drill group-containing highly saturated copolymer A rubber composition comprising: a polymer rubber; and another rubber.

Is provided.

The following are provided as preferred embodiments of the rubber composition of the present invention.

(2) an acid equivalent of 1 X 10- ⁴ ephr above, [peak height of the force carboxylic acid anhydride group] in the infrared absorption analysis / ([peak height of a carboxylic acid anhydride group] + [peak height of a carboxyl group]) Is 0.5 or more, and the Mooney viscosity (ML ι ₊ 4, 100 ° C) is 15 to 200 and the carboxylated nitrile group-containing highly saturated copolymer rubber having an iodine value of 80 or less, and other rubbers A rubber composition characterized by comprising:

(3) The rubber composition according to (1) or (2), wherein the carboxylated nitrile group-containing highly saturated copolymer rubber has a methylethylketone-insoluble content of 10% by weight or less. Adult.

(4) The rubber composition according to any one of (1) to (3), wherein the amount of bound nitrile of the carboxylated nitrile group-containing highly saturated copolymer rubber is 10 to 60% by weight.

(5) The carboxylated nitrile group-containing highly saturated copolymer rubber is obtained by adding hydrogen and ethylenically unsaturated carboxylic acid or its anhydride to an acrylonitrile-butadiene copolymer rubber. The rubber composition according to any one of (1) to (4).

(6) The other rubber is a heat-resistant rubber, preferably a rubber selected from a nitrile group-containing copolymer rubber, an acrylic rubber, an ethylene propylene rubber, an ethylene propylene diene rubber, a fluorine rubber, and an ephalohydrin rubber. 1) The rubber composition according to (5).

(7) The rubber composition according to (6), wherein the nitrile group-containing copolymer rubber is a hydrogenated nitrile group-containing copolymer rubber (or a nitrile group-containing highly saturated copolymer rubber).

(8) The rubber composition according to any one of (1) to (7), further comprising a crosslinking agent.

According to the present invention,

(9) acid equivalent of 1 X 1 0 ⁴ ephr above, arm one knee viscosity _{(ML 1 + 4, 1 00} ° C) is 15 to 200 and carboxylation of 80 or less iodine value two preparative drill group-containing highly saturated copolymer A strength modifier for rubber, comprising a polymer rubber;

Is provided.

As preferred embodiments of the rubber strength modifier of the present invention, the following are provided ^) o

(10) acid equivalent of 1 X 10- ⁴ ephr above, in the infrared absorption analysis [force Peak height of sulfonic anhydride group] / ([Peak height of carboxylic anhydride group]

+ [Carboxyl group peak height]) is 0.5 or more, and the carboxylated nitrile group containing carboxylic acid having a viscosity of ML 1 _{+ 4} (100 ° C) of 15 to 200 and iodine value of 80 or less is highly saturated. A strength modifier for rubber, comprising a copolymer rubber.

(11) The rubber strength modifier according to any one of (9) to (10), wherein the carboxylated nitrile group-containing highly saturated copolymer rubber has a methylethylketone insoluble content of 10% by weight or less.

(12) The rubber strength modifier according to any one of (9) to (11), wherein the amount of bound nitrile of the carboxylated nitrile group-containing highly saturated copolymer rubber is 10 to 60% by weight.

(13) The carboxylated nitrile group-containing highly saturated copolymer rubber is obtained by adding hydrogen to an acrylonitrile-butadiene copolymer rubber and an ethylenically unsaturated carboxylic acid or an anhydride thereof. (9) The strength modifier for rubber according to (12).

The carboxylated nitrile group-containing highly saturated copolymer rubber used in the present invention is a copolymer having a nitrile group in the molecule, having few carbon-carbon unsaturated bonds, and exhibiting rubber elasticity. It has a carboxyl group in the molecule.

The amount of carbon-carbon unsaturated bonds in the carboxylated nitrile group-containing highly saturated copolymer rubber is expressed by an iodine value instead. The rubber of the present invention has an iodine value of 80 or less, preferably 60 or less. If the iodine value is too large, oil resistance and heat resistance will decrease.

Bound nitrile units in highly saturated copolymers containing carboxylated nitrile groups. Although the amount of is not particularly limited, it is usually 10 to 60% by weight, preferably 15 to 40% by weight. Oil resistance and heat resistance increase as the amount of the binding nitrile unit increases, and rubber elasticity increases as the amount of the binding nitrile unit decreases. Therefore, it is appropriately selected according to the application.

Acid equivalent of carboxylated nitrile group-containing highly saturated copolymer rubber, IX 10 ^"4 ephr or more, preferably ^{^{2x l 0_ 3 ~5x l 0- 2}} ephr, preferably in the al 5x l 0- ³ to 3 a xl 0- ² ephr. acid equivalent is less the Most such as tensile strength Ya wear resistance of the rubber is lowered.

The acid equivalent was determined by dissolving the rubber in acetone and reprecipitating and refining with n-hexane. The reprecipitated and purified rubber was redissolved in pyridine. It is a value obtained by titration using an ethanol solution of potassium with thymolphthalein as an indicator and as an equivalent to 100 g of rubber.

In the infrared absorption analysis of a highly saturated copolymer rubber containing a carboxylated nitrile group, the value of [peak height of acid anhydride group] / ([peak height of acid anhydride group] + [peak height of lipoxyl group]) is as follows. Although not particularly limited, it is usually 0.5 or more, preferably 0.7 or more, and more preferably 0.8 or more. If this value is too small, scorch is likely to occur at the time of crosslinking, and the abrasion resistance becomes insufficient and the compression set tends to increase.

The carboxylated nitrile group-containing highly saturated copolymer rubber has a viscosity of 12 to 21 (ML _{1 +4} , 100 ° C) of 15 to 200, preferably 30 to 150. If the viscosity is too high, the kneadability of the rubber will be poor, and if it is too low, the durability of the rubber under high pressure will be insufficient, resulting in permanent compression set and crushing (compression relaxation). Becomes insufficient. The amount of the methylethyl ketone insoluble portion of the carboxylated nitrile group-containing highly saturated copolymer rubber is usually 10% by weight or less, preferably 5% by weight or less, more preferably 2% by weight or less. If the amount of methylethyl ketone-insoluble components is too large, the processability of rubber becomes poor, and the tensile strength and elongation decrease.

The amount of methylethyl ketone insolubles was determined by finely chopping the rubber, placing it in an 80-mesh wire mesh basket, immersing this basket in methyl ethyl ketone at room temperature for 48 hours, and remaining in the basket. The solid content is dried, the weight of the dried product is measured, and the weight of the dried product relative to the weight of the rubber initially placed in the basket is expressed as a percentage.

The method for producing the carboxylated nitrile group-containing highly saturated copolymer rubber used in the present invention is as follows: a nitrile group-containing highly saturated copolymer rubber and an ethylenically unsaturated copolymer are placed in a chemical reaction vessel such as an autoclave. A method in which a carboxylic acid solution is charged and subjected to an addition reaction by heating; a method of kneading a nitrile group-containing highly saturated copolymer rubber and an ethylenically unsaturated carboxylic acid with a peroxide to perform a radical addition reaction; In a kneader, a nitrile group-containing highly saturated copolymer rubber and an ethylenically unsaturated carboxylic acid or an anhydride thereof are subjected to an ene-type addition reaction. Of these, the method of performing the addition reaction can increase the value of [peak height of carboxylic acid anhydride group] Z ([peak height of carboxylic acid anhydride group] + [peak height of carboxyl group]). This is preferable because it can be easily performed.

The nitrile group-containing highly saturated copolymer rubber used in the method for producing a carboxylated nitrile group-containing highly saturated copolymer rubber is composed of an ethylenically unsaturated nitrile and a conjugated gen unit portion of a monoconjugated gen-based copolymer rubber. Hydrogenated is there. .

In the nitrile group-containing highly saturated copolymer rubber, the amount of the bound nitrile unit is usually 10 to 60% by weight, preferably 15 to 40% by weight, and the iodine value is usually 80 or less, preferably 60 or less, and the Mooney viscosity (ML1 _{+ 4} , 100 ° C) is usually in the range of 30 to less than 300, preferably in the range of 50 to 200, More preferably, it is in the range of 60 to 150. If the iodine value is too large, the heat resistance and strength of the rubber will decrease. The lower limit of the iodine value is not particularly limited. However, if the iodine value is excessively low, it may be difficult to crosslink the rubber. If the viscosity is too low, the durability of the rubber under high pressure is insufficient, and the compression set and crushing (compression relaxation) are not improved. On the other hand, if the Mooney viscosity is too high, the processability of the rubber during kneading deteriorates.

The ethylenically unsaturated nitrile-conjugated gen copolymer used for producing the nitrile group-containing highly saturated copolymer rubber is usually a monomer containing ethylenically unsaturated nitrile and a conjugated gen. It is obtained by polymerizing a body mixture.

Specific examples of ethylenically unsaturated nitriles include ethylenically unsaturated nitriles such as acrylonitrile, methacrylonitrile, ethyl acrylonitrile, methoxyacrylonitrile, and the like. Of these, acrylonitrile is preferably used. The amount of ethylenically unsaturated nitrile is usually from 10 to 60% by weight in the monomer mixture.

Specific examples of the conjugated diene include 1,3-butadiene, 2,3-dimethylbutadiene, isoprene, 1,3-pentadiene, and chloroprene. Of these, 1,3-butadiene is preferably used. Both The amount of the acting agent is usually 40 to 90% by weight in the monomer mixture. In the case where 1,3-butadiene and isoprene are used together as the conjugated gen (ie, in the case of isoprene-butadiene-acrylonitrile copolymer rubber), the amount of 1,3-butadiene bonded to the total amount of the conjugated gen is usually determined. Is 30 to 70% by weight, and the amount of bound isoprene is 70 to 30% by weight.

The monomer mixture may contain 0 to 50% by weight of an ethylenically unsaturated monomer copolymerizable with ethylenically unsaturated nitrile and a conjugated diene.

Specific examples of ethylenically unsaturated monomers copolymerizable with ethylenically unsaturated nitrile and conjugated diene include:

Vinyl aromatic compounds such as styrene and α-methylstyrene; methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylyl Propyl acid, dimethyl maleate, getyl maleate, dipropyl maleate, di-maleic acid butyl ester, diisobutyl maleate, di-maleic acid η-pentyl, di-maleic acid η-hexyl, di-maleic acid 2-ethylhexyl, dimethyl fumarate, getyl fumarate, dipropyl fumarate, di-η-butyl fumarate, diisobutyl fumarate, di-η-fumarate —pentyl, di-η-fumarate —hexyl, di-fumarate 2-ethylhexyl, dimethyl itaconate, itaconic acid Tyl, dipropyl itaconate, di-itaconate di-tert-butyl, diisobutyl itaconate, di-itaconate η-pentyl, di-itaconate-η-hexyl, di- 2-ethyl itaconate hexyl, di-citraconic acid To methyl, getyl citrate, dipropyl citrate, di-n-butyl citrate, diisobutyl citrate, di-n-pentyl citrate, pentyl, di-n-hexyl citrate, and di-2-ethyl citrate Xyl, Dimethyl Mesaconate, Getyl Mesaconate, Dipropyl Mesaconate, Di-n-butyl Mesaconate, Diisobutyl Mesaconate, Di-n-pentyl Mesaconate, Di-n-hexyl Mesaconate, Di-mesaconate — 2 —Ethylhexyl, dimethyl glutaconate, getyl glutaconate, dipropyl glutaconate, di-n-butyl glutaconate, diisobutyl glutaconate, di-n-pentyl glutaconate, di-n-pentyl glutaconate, n-hexyl glutaconate, glutaconate di-2 —Ethylhexyl, dimethylallylmalonate, aryl Getyl rumalonate, dipropyl arylmalonate, di-n-butyl arylmalonate, diisobutyl arylmalonate, di-n-pentyl arylmalonate, di-n-hexyl arylmalonate, di-1-2-ethylhexyl arylmalonate, terraconic acid Dimethyl, Jethyl terraconate, Dipropyl terraconate, Di-n-butyl terraconate, Diisobutyl terraconate, Di-n-pentyl terraconate, Di-n-hexyl terraconate, Di-2-hexyl terraconate Ethylenically unsaturated carboxylic acid alkyl esters such as;

Ethylenically unsaturated carboxylic acid alkoxyalkyl esters such as methoxyacrylate, ethoxyxylacrylate, methoxetixylacrylate;

<¾— and monocyanoethyl acrylate, α—, / 3— and arcynopropyl acrylate, cyanobutyl acrylate, cyanooctyl acrylate, α— and / 3-cyanoethyl methacrylate, a-1, yS- and 7-cyanopropyl methacrylate, cyanobutyl methacrylate, cyanooctyl methacrylate, ethylenically unsaturated carboxylic acid cyano-substituted alkyl esters;

Substitution of ethylenically unsaturated carboxylic acid hydroxyl groups such as 2-hydroxyl acrylate, hydroxypropyl acrylate, 2-hydroxyl methacrylate, hydroxypropyl methacrylate Al quinole estenore;

Acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylolacrylamide, N-ethoxymethylacrylamide, N-methylmethacrylamide, N, N-dimethylolmeta Ethylenic unsaturated amides such as acrylamide and N-ethoxymethyl methacrylamide;

Non-conjugated diene such as vinyl norbornene, dicyclopentadiene, 1,4-hexadiene;

Ethylenically unsaturated carboxylic acid fluoroalkyl esters;

And the like.

Specific examples of the ethylenically unsaturated nitrile-one conjugated copolymer rubber include acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-butadiene-isoprene copolymer rubber (NBIR), and acrylonitrile-one rubber. Isoprene copolymer rubber (NIR), acrylonitrile butadiene butoxy acrylate copolymer rubber, atarilonitrile butadiene-acrylic acid copolymer rubber, acrylonitrile-butadiene-methacrylic acid copolymer Coalesced rubber and the like. Of these, NBR is preferably used. Such an ethylenically unsaturated nitrile-conjugated gen-based copolymer rubber is usually used in combination with an ethylenically unsaturated nitrile and a conjugated gen in the presence of a radical polymerization initiator, if necessary, using a molecular weight modifier as necessary. It is prepared by copolymerizing other ethylenically unsaturated monomers accordingly. As polymerization auxiliary materials such as a radical polymerization initiator and a molecular weight regulator, those commonly used in known polymerizations can be used.

The method of polymerization is not particularly limited, and bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, or the like can be appropriately selected as necessary. Among them, emulsion polymerization is preferred. In the case of production by emulsion polymerization, for example, polymerization is carried out by a known emulsion polymerization technique, and when a predetermined conversion is reached, hydroxylamine, sodium carbamic acid, etc. are added to terminate the polymerization, and then the remaining The monomers are removed by heating, steam distillation, etc., and the obtained polymer latetus is further coated with a coagulant used in ordinary emulsion polymerization such as an inorganic coagulant, a polymer coagulant or a thermosensitive coagulant. By the addition, the copolymer can be coagulated and recovered.

The method for hydrogenating the conjugated gen unit of the ethylenically unsaturated nitrile-conjugated gen-based copolymer rubber is not particularly limited, and is carried out by using a usual hydrogenation method.

Specifically, the hydrogenation is carried out by blowing hydrogen into a solution of ethylenically unsaturated nitrile-one conjugated copolymer rubber dissolved in a solvent in the presence of a hydrogenation catalyst.

The solvent is capable of dissolving the ethylenically unsaturated two-trilu-conjugated gen-based copolymer rubber. Specifically, aromatic compounds such as benzene, toluene, xylene, and chlorobenzene; Ketones such as chillethyl ketone and getyl ketone; tetrahydrofuran; ethyl acetate; dimethylformamide. Examples of the hydrogenation catalyst include palladium silica and a palladium complex (JP-A-3-252405). Further, described in JP-A-62-125858, JP-A-62-42937, JP-A-11-45402, JP-A-11-45403, JP-A-11-45404, JP-A-1-45405, etc. Rhodium or ruthenium compounds as described can also be used.

The hydrogenation reaction temperature is usually 5 to 150 ° C, preferably 10 to 100 ° C. At a high temperature, a side reaction such as deactivation of the hydrogenation catalyst or hydrogenation of the nitrile group tends to occur.

The ethylenically unsaturated carboxylic acid or its anhydride used for carboxylating the nitrile group-containing highly saturated copolymer rubber is not particularly limited, but the ethylenically unsaturated dicarboxylic acid having 4 to 10 carbon atoms or its ethylenically unsaturated carboxylic acid or its anhydride is used. Anhydrides, especially maleic anhydride, are preferred.

Examples of ethylenically unsaturated carboxylic acids include ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; ethylenically unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid; and maleic anhydride. , Ethylenically unsaturated dicarboxylic anhydrides such as itaconic anhydride and citraconic anhydride; monomethyl maleate, monoethyl maleate, monopropyl maleate, mono-mono-maleic acid η-butyl, monoisobutyl maleate, monoethyl maleate Mono-η-pentyl, mono-maleic-hexyl maleate, mono-2-ethylhexyl maleate, monomethyl fumarate, monoethyl fumarate, monopropyl fumarate, mono-mono-fumarate , Monoisobutyl fumarate, mono-n-fumarate, pentyl, mono-n-hexyl fumarate, mono-ethyl-2-hexyl fumarate, monomethyl itaconate, monoethyl itaconate, monopropyl itaconate, mono-itaconate n-butyl, monoisobutyl itaconate, mono-itaconate n-pentyl, mono-itaconate η—hexyl, mono-itaconate 2-ethylhexyl, monomethyl citrate, monoethyl citrate, monopropyl citrate, citracone Acid mono-η-butyl, citraconic acid monoisobutyl, citraconic acid mono-η-pentyl, citraconic acid mono-η-hexyl, citraconic acid mono-2-ethylhexyl, monomethyl mesaconic acid, monoethyl mesaconic acid, Monopropyl mesaconate, mesacon Mono-η-acid butyl, monoisobutyl mesaconic acid, mono-methaconate η-pentyl, mono-mesaconate η-hexyl, mono-l-ethyl 2-hexyl mesaconate, monomethyl glutaconate, monoethyl glutaconate, monopropyl glutaconate Mono-η-butyl glutaconate, monoisobutyl glutaconate, mono-η-pentyl glutaconate, mono-η-hexyl glutaconate, mono-2-ethylhexyl glutaconate, monomethyl arylmalonate, monomethyl arylmalonate, monoethyl arylmalon, arylmalon Monopropyl acid mono-η-butyl arylmalonate, Monoisobutyl arylmalonate, Mono-η-pentyl arylmalonate, Mono-η-hexyl arylmalonate, Mono-2-ηethylhexyl arylmalonate, Monomethyl terraconate Monoethyl terraconate, monopropyl terraconate, mono-η-butyl terraconate, monoisobutyl terraconate, mono- terraconate- η-pentyl, mono- terraconate η-hexyl, mono-teraconate-2-ethylhexyl, etc. Unsaturated dicarboxylic acid monoalkyl ester And the like.

The method of the addition reaction is not particularly limited. Specific examples include a method of performing an ene-type addition reaction by kneading the nitrile group-containing highly saturated copolymer rubber with an ethylenically unsaturated carboxylic acid or an anhydride thereof, and a nitrile group-containing highly saturated copolymer. A method in which a radical type addition reaction is carried out by kneading a polymer rubber with an ethylenically unsaturated carboxylic acid or its anhydride and a peroxide, and adding a solution of a nitrile group-containing highly saturated copolymer rubber to an ethylenically unsaturated carboxylic acid. A method of performing an addition reaction by adding saturated carboxylic acid or its anhydride and applying pressure. Of these methods, the enzymatic addition reaction method is preferred.

In order to carry out the ene-type addition reaction, the nitrile group-containing highly saturated copolymer rubber and the ethylenically unsaturated carboxylic acid or its anhydride are usually kneaded at a high temperature without using a radical generator. I do.

The use of a radical generator causes gel formation and an increase in the Mooney viscosity of the rubber, and radical-type addition of an ethylenically unsaturated carboxylic acid or its anhydride with a nitrile group-containing highly saturated copolymer rubber. Since the reaction occurs, it becomes impossible to carry out an ene-type addition reaction.

The amounts of the nitrile group-containing highly saturated copolymer rubber and the ethylenically unsaturated carboxylic acid or anhydride thereof are not particularly limited, but usually, the amount of the nitrile group-containing highly saturated copolymer rubber is 100 parts by weight. The amount of the ethylenically unsaturated carboxylic acid or anhydride thereof is 0.05 to 10 parts by weight, preferably 0.2 to 6 parts by weight.

The rubber strength modifier of the present invention comprises the above-mentioned carboxylated nitrile group-containing highly saturated copolymer rubber. The strength modifier for rubber of the present invention is distributed to rubber. By the combination, the rubber composition containing the rubber can have high tensile strength and tensile stress.

The rubber composition of the present invention has an acid equivalent constituting the rubber strength modifier of at least 1 × 10 ⁴ ephr, and has a Mooney viscosity (ML _{1 +4} , 100 ° C.) of 15 to 150 ° C. A highly saturated copolymer rubber containing a carboxylated nitrile group having an iodine value of at most 80 and other rubbers, and other rubbers. Examples of rubbers include polybutadiene rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, butyl acrylate-butadiene copolymer rubber, ethyl acrylate-butadiene copolymer rubber, and butyl acrylate-butyl acrylate rubber. To-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylonitrile-styrene-butadiene copolymer rubber, acrylonitrile-lilubutyl acrylate Conjugated gen-based polymer rubbers such as tobutadiene copolymer rubber, atarilonitrile ruethyl acrylate, butadiene copolymer rubber, butyl acrylate, tostyrene-butadiene copolymer rubber, and the like; highly saturated copolymer rubber containing a nitrile group A highly saturated conjugated polymer rubber obtained by adding hydrogen to a carbon-carbon unsaturated bond portion of the conjugated polymer rubber; a carboxyl group-containing conjugate obtained by copolymerizing a monomer having a carboxyl group; Gen-based copolymer rubber; vinylidene fluoride-hexafluoropropylene copolymer rubber, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer rubber, tetrafluoroethylene-propylene Copolymer rubber, fluorinated silicone rubber, fluorophos Azengomu, Te trough Ruo Russia ethylene - Full O b such vinyl ether copolymer rubber fluorine rubber; And polymer segments of fluorosegment, such as vinylidene fluoride hexafluoropropylene copolymer rubber, etc., and ethylene-tetrafluoroethylene copolymer resin, vinylidene fluoride resin, etc. Fluorinated block copolymer rubber composed of a hard-segment polymer block composed of a fluororesin, such as: epichlorohydrin rubber, ethylenoxyde-epichlorohydrin copolymer rubber, and propylene oxide dopechlorochlorohydrin copolymer rubber , Ethylene glycol-epichlorohydrin-aryl glycidyl ether copolymer rubber, ethylenoxy-do-propylene-doxychlorohydrin copolymer rubber, propylene oxide-aryl glycidyl ether, etc. Rieterugomu;

Ethylene copolymer rubber, such as ethylene-propylene copolymer rubber, ethylene-propylene-non-conjugated gen copolymer rubber, ethylene-propylene-1-1-butene-non-conjugated gen copolymer rubber; ethyl acrylate, propyl acrylate Copolymer rubbers containing alkyl acrylate units or methoxyalkyl acrylate units having an alkyl group having 8 or less carbon atoms such as butyl acrylate, butyl acrylate, etc. (so-called acrylic rubber), and epoxy groups in the structure. And cross-linkable acryl rubber containing vinyl group, etc .; polyurethane rubber; silicone rubber;

Of these other rubbers, so-called heat-resistant rubbers are preferred. Specifically, a nitrile group-containing conjugated polymer rubber such as an acrylonitrile-butadiene copolymer rubber; a nitrile group-containing highly saturated conjugated polymer rubber such as a hydrogenated acrylonitrile-butadiene copolymer rubber : Acryl rubber; Polyether rubber; Fluorine rubber; and Ethylene rubber No. Of these, nitrile group-containing highly saturated conjugated polymer rubbers are preferred. The other rubbers listed above can be used alone or in combination of two or more. The ratio of the highly saturated copolymer rubber containing ropoxylated nitrile group to other rubbers (the highly saturated copolymer rubber containing carboxylated nitrile group and other rubber) that constitutes the rubber strength modifier is On a weight basis, it is usually from 199 to 90, preferably from 190 to 80.

The rubber composition of the present invention may further contain a crosslinking agent. As the crosslinking agent, those commonly used for crosslinking rubber can be used.

Specifically, sulfur; sulfur-donating compounds, for example, thiuram compounds such as morpholine disulfide and tetramethylthiuram disulfide; dicumyl peroxide, di (t-butylperoxy) diisopropylbenzene, and 2,5-di-t-butylperoxy. one 2, key San into 5- dimethyl, peroxides such as benzo I helper O wherein de, and the like _c which are used alone or in combination of two or more.

The amount of the crosslinking agent is usually 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the carboxylated nitrile group highly saturated copolymer rubber. .

For efficient crosslinking, a crosslinking aid and a crosslinking accelerator may also be included in the composition of the present invention. Crosslinking assistants and accelerators include maleimide compounds such as maleimide and phenylene bismaleide; zinc oxide, zinc peroxide, activated zinc, zinc carbonate, magnesium oxide, lead monoxide, Polyvalent metals such as lead gallium and calcium hydroxide and their compounds; stearic acid, oleic acid, lauric acid, zinc stearate, zinc laurate, etc. And derivatives thereof; and the like. Of these, it is preferable to use a polyvalent metal compound or a fatty acid derivative, particularly a fatty acid polyvalent metal salt, specifically, zinc stearate, because the tensile strength of the crosslinked rubber and the abrasion resistance are improved. . Further, it is preferable to use a combination of a polyvalent metal salt of a fatty acid and a polyvalent metal compound, specifically, zinc stearate and zinc oxide.

The rubber composition of the present invention may further contain an antioxidant, a filler or a reinforcing agent, a fiber reinforcing material, a conductivity-imparting agent, a plasticizer or a softening agent, a foaming agent, a tackifier, and a scorch inhibitor, if necessary. , A colorant, a lubricant, a dispersant, and the like.

Industrial applicability

The rubber composition of the present invention is obtained by subjecting it to cross-linking molding or compounding with a fiber to form a roll such as a roll for ink printing, a roll for an electrostatic image forming device, or a paper feed roll; Hose or tube such as hydraulic hose, hydraulic hose, fuel hose; belt such as V-belt, poly V-belt, toothed transmission belt; tire; wire covering material; sponge; can do. In addition, vibration damping materials (vibration-proof materials); spring materials; anti-fog materials; seal materials such as 0-rings, gaskets, oil seals, and freon seals; sliding materials such as clutch plates and brake shoes for automobiles (Friction material);

BEST MODE FOR CARRYING OUT THE INVENTION

[Example]

Hereinafter, the present invention will be described more specifically with reference to examples. Note that the embodiment Parts and percentages are by weight unless otherwise specified. Further, the present invention is not limited by these examples.

The measurement and analysis methods performed in this example and the like are as _follows.c

[Measurement of acid equivalent]

After dissolving the carboxylated rubber M (g) in acetone and reprecipitating and purifying with n-hexane, the reprecipitated and purified rubber is redissolved in pyridine (special grade of JIS K-8777 reagent). Using an ethanol solution of 0.02 N potassium hydroxide, titration was performed using thymolphthalein as an indicator to obtain a titer A (ml), while the rubber M (g) before carboxylation was obtained in the same manner. To obtain a titration value B (ml).

Acid equivalent (ephr) = [(A-B) x 0.02 x 100] /

[1000 XM]

The acid equivalent was calculated according to

[Measurement of carboxylic acid addition rate]

The ratio (%) of the amount of carboxylic acid addition calculated by converting the acid equivalent to the amount of maleic anhydride charged was calculated, and the result was defined as the carboxylic acid addition rate.

[Measurement of carboxylic acid residual rate]

The carboxylated rubber is dissolved in pyridine, and the amount of carboxylic acid is measured by titrating this solution using an ethanolic solution of ruthenium hydroxide with thymolphthalein as an indicator to determine the acid equivalent. Then, the amount of addition was subtracted from this amount, and the ratio (%) of the obtained value to the amount of maleic anhydride charged was calculated to obtain the carboxylic acid residual ratio.

[Infrared absorption analysis]

Infrared absorption analysis group (ST Japan Co., Ltd., Iris scanning) Was analyzed using an infrared microscopy system.

The carboxylic acid anhydride group in the vicinity of 1785 cm- ^1, the carboxyl group is 17 10: peak appears in the vicinity of L 740 cm- ^1.

[Measurement of MEK insoluble content]

Finely chop the rubber, place it in an 80 mesh wire mesh basket, immerse the basket in methyl ethyl ketone at room temperature for 48 hours, dry the solids remaining in the basket, and weigh the dried material. Calculate the percentage of the weight of the dry matter relative to the weight of the rubber initially placed in the basket and determine the amount of the MEK-insoluble matter as ο

[Tensile test]

Prepare a cross-linked rubber sheet with a thickness of 2 mm, punch out the sheet using a No. 3 dumbbell, and use the punched piece according to JISK 6301, a tensile speed of 50 Omm, and a check distance. A tensile test was performed under the conditions of 20 mm, a temperature of 25 ° C, and a humidity of 50% RH, and the stress at 300% elongation, the tensile strength, and the elongation were measured.

[Measurement of wear loss]

Pico abrasion tests were performed according to ASTM D 2228-88 to determine wear loss. A smaller value indicates higher abrasion resistance.

[Adhesion test with fiber]

A base fabric made of fiber is superimposed on a sheet molding made of a rubber composition, pressed at a pressure of 5 MPa at a temperature of 150 ° C for 30 minutes, crosslinked, and a laminate of the base fabric and rubber (composite) I got

This composite was punched into a size of 25 mm x 150 mm, and a peel test was performed using an Instron type tensile tester at a tensile speed of 5 OmmZ. As the above-mentioned base cloth, a surface-treated nylon cloth obtained by immersing a base cloth made of nylon 66 fiber in hydrogenated acrylonitrile butadiene rubber latex and then heat-treating it at 180 ° C. for 2 minutes; A surface-treated glass fiber base fabric obtained by immersing a glass fiber base fabric in hydrogenated acrylonitrile butagen rubber latex and then heat-treating it at 180 ° C for 2 minutes; and Nylon 66 fiber The base fabric was used.

[Cold resistance test]

It was evaluated by a TR test according to ASTM-D1329. The temperature (TR-10) at which the length of the test specimen recovers 10% by heating after freezing the elongated test specimen was expressed (unit: ° C). The lower the temperature, the better the cold resistance.

[Air heating aging test]

After leaving the test piece at 190 ° C. for 0 hours, the elongation (%) was measured according to JIS K 6301, and the rate of change (%) with respect to the elongation (%) before being left under the above temperature conditions was determined. If the rate of change is negative, it indicates that growth has decreased.

[Measurement of compression set]

According to JIS K6301, the test piece was kept in air at 150 ° C. for 70 hours and then measured.

[Measurement of low temperature compression set]

According to JIS K6301, the test piece was kept in air at 120 ° C for 70 hours and then measured.

[Oil resistance test]

Lubricating oil No. 3 (Kinematic viscosity 31.9 to 34. 1, the aniline point 69.5 ± 1. C, flash point 162.7 ° C), immerse the rubber test piece, leave it at 150 ° C for 70 hours, and calculate the volume change rate from before the immersion o

[Evaluation of roll kneading property]

When kneading rolls, the ones that can be kneaded normally: 作業, those that could not be kneaded due to sticking or wrapping around the rolls: △, those that had difficulty in kneading: X The kneading performance was evaluated using the following indicators.

[Tensile test]

According to JIS K 6301, the test was performed using a B-type test piece.

[Rebound resilience test]

Performed in accordance with JIS K 6301.

Example 1

Nitrile group-containing highly saturated polymer rubber (hydrogenated acrylonitrile-butadiene copolymer rubber, iodine value 28, bound nitrile unit content in rubber 36%, rubber viscosity 58, 100 parts were masticated for 3 minutes using a pressurized drier (Moriyama Seisakusho, mixing volume 75 liters, MS type), which is a heated and sealed kneader.

At this time, steam with a vapor pressure of 3 kgZcm ² was flowed through the jacket of the pressurizing tank (jacket of the mixing tank, side plate, pressurizing lid and blade shaft), and the jacket was heated to 130 ° C. The blade was operated under the conditions of a blade rotation speed of 30/25 rpm, a pressure lid of 8 kg gZcm ² and a shear rate of 500 ns. The filling rate in the pressurized kneader is about 89.5% by volume based on the total capacity of the kneader. After the rubber temperature rose to 130 ° C, 1.8 parts of maleic anhydride and 0.5 part of 2,6-di-tert-butyl-14-methylphenol (BHT) heated and melted at 65 ° C were added. The mixture was charged into a pressurized kneader using a plunger pump, and was continuously kneaded (pre-kneaded).

Using the shear heat generated by kneading, the rubber temperature was adjusted to 250 ° C, and kneading was performed at that temperature for another 15 minutes to carry out an ene-type addition reaction. The rubber temperature was controlled by changing the temperature of high-pressure hot water flowing through the jacket of the pressurized cylinder, or by changing the pressure of the pressurized lid of the pressurized cylinder. .

Finally, the mixing tank of the pressurized mixer is lowered, and the mixture is pulverized for about 30 seconds, the rubber mixture is dropped, taken out of the pressurized mixer, and a highly saturated copolymer containing a carboxylated nitrile group is contained. A modifier consisting of rubber (hereinafter, this rubber is sometimes referred to as “carboxylated H—NBR 1J”) was obtained. No stain was found on the blade of the pressure kneader. Are shown in Table 1.

Example 2

A carboxylated nitrile group-containing highly saturated copolymer rubber (hereinafter referred to as “carboxylated H”) was prepared in the same manner as in Example 1 except that the amount of maleic anhydride was changed to 0.7 part. — NBR 2 ”). Table 1 shows the physical properties of this modifier.

Example 3

A carboxylated nitrile group-containing highly saturated copolymer rubber (hereinafter referred to as “carboxylated H”) was prepared in the same manner as in Example 1 except that the amount of maleic anhydride was changed to 3.5 parts. — NB R 3 ”.) Was obtained. Table 1 shows the physical properties of this modifier.

table 1

Infrared absorption analysis: It is the value of [peak height of carboxylic acid anhydride group] ([peak height of carboxylic acid anhydride group] + [peak height of carboxyl group]). Comparative Example 3 was not measured because the addition rate was low. Example 4 (Modification of polyether rubber)

70 parts of the modifier obtained in Example 1, polyether rubber [ethylene oxide (90 mol%)-propylene oxide (10 mol%) copolymer rubber, reduced viscosity (7? SpZC) 5. 3 (11, hereinafter sometimes referred to as "Polymer 1".) 30 parts, zinc oxide 5 parts, zinc stearate 1 part, magnesium oxide 5 parts, lubricant (fatty acid metal salt, Gretz G-8205) 1 Parts, Silica (Carplex 1120) 40 parts, 1,3-bis (3-butylperoxyisopropyl) benzene (concentration 40%) 4 parts, Gethylene glycol 2 parts, Silane coupling agent (A172) 1. Five parts, 1 part of 2-mercaptobenzoimidazole zinc salt (Nocrack MBZ) and 1 part of substituted diphenylamine (Naugard # 445) were mixed with a roll to obtain a rubber composition. Crosslinked under pressure at C or 170 ° C. Evaluation results of the rubber composition and its crosslinked product are set forth in Table 2 shows Examples 5-6 and Comparative Examples 1-3

A rubber composition and a crosslinked product were obtained in the same manner as in Example 4, except that the modifying agent and E0 polymer 1 used in Example 4 were changed to those having the combination formulation shown in Table 2. Table 2 shows the results.

Table 2

O polymer 2: Ethylene oxide (90 mol%)-Propylene oxide (5 mol%)-arylglycidyl ether (5 mol%) Copolymer rubber, reduced viscosity (sp / C) 4.7 d 1 / g

O-polymer: Propylene oxide (97 mol%)-arylidelicidyl ether (3 mol%) copolymer rubber, viscosity of 70 Table 2 shows that when the modifier of the present invention was used (Examples 4 to 6), the tensile strength and the tensile stress were higher than when the modifier composed of H—NBR was used (Comparative Examples 1 to 3). It can be seen that the rate of change in elongation in the air heating aging test decreases.

Example 7 (Modification of ethylene rubber)

30 parts of the modifier obtained in Example 2, ethylene rubber (EPDM, Mitsui EPT 4070, Muney viscosity 68, iodine value 22) 50 parts, zinc oxide 5 parts, stearate 1 part, carbon Black (SRF) 40 parts, sulfur (325 mesh) 0.5 parts, tetramethylthiuram disulphide 1.5 parts, N-cyclohexyl-1-2-benzothiazyl sulfonamide 1 part And 1 part of an amide-based antioxidant (Nowgard # 445, manufactured by Hercules) was mixed with a roll to obtain a rubber composition. This rubber composition was pressure-crosslinked at 150 ° C. or 160 ° C. Table 3 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Examples 8 to 9 and Comparative Examples 4 to 5

A rubber composition and a crosslinked product were obtained in the same manner as in Example 7, except that the modifier and EPDM used in Example 7 were changed to those of the compounding recipe shown in Table 3. Table 3 shows the results.

Table 3

Example Comparative example

7 8 9 4 5 Formulation

Modifier

Carboxylated H—NBR 2 30 50 70--

H-NB R 1 1 1 50-Rubber

E P DM 70 50 30 50 100

5l trial

(Crosslinking: 1 60 ° C, 20 minutes)

Tensile strength [kg / cm ² ) 186 206 217 167 118 Elongation [%] 380 380 390 410 380

100% tensile stress [kg / cm ² ] 58 58 43 28 22 Hardness (JISA) 70 72 69 68 65 Compression set

1 50 ° C, 70 hours [%] 28 30 31 38 36 Oil resistance test 1 50 ° C, 70 hours

Volume change rate (%) 61 56 42 66 87 Cold resistance test

TR I O (° C)-33 -31 -30 -28 -45 Pico abrasion test

Wear amount ^{[X 1 0- 4 cc] 234} 156 243 276 328

As can be seen from Table 3, the tensile strength was higher when the modifier of the present invention was used (Examples 7 to 9) than when the modifier composed of H—NBR was used (Comparative Example 4). It can be seen that the compression set and the wear loss are reduced.

Example 10 (Modification of acryl rubber)

30 parts of the modifier obtained in Example 1, 70 parts of acrylic rubber [AR1, ethyl acrylate (98 mol%)-vinyl chloroacetate (2 mol%) copolymer rubber, municipality of 50], stearyl 1 part acid, 50 parts carbon black (FEF), 5 parts zinc oxide, 2 parts zinc stearate, 1 part PZ (Zinc dimethyldithiocarbamate, Noxera-I PZ, Ouchi Shinkosha), 1 part and TTF e (Iron dimethyldithiocarbamate, Noxeller TTF E, manufactured by Ouchi Shinko Co., Ltd.) 0.5 part was mixed with a roll to obtain a rubber composition. This rubber composition was crosslinked at about 155 ° C. Table 4 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Examples 11 to 12 and Comparative Examples 6 to 7

A rubber composition and a crosslinked product were obtained in the same manner as in Example 10, except that the modifier and the acrylic rubber used in Example 10 were changed to those having the composition shown in Table 4. Table 4 shows the results.

Table 4 Example Comparative example

10 11 12 6 7 Formulation [Parts]

Modifier

Carboxylated H— NBR 1 30 50 70

H-NB R-one-50-rubber

AR 1 70 50 30 50 100 Roll kneadability 〇〇 Δ Δ Δ Tensile test

(Primary crosslinking: 1 55 ° C, 30 minutes

Secondary crosslinking: 150 ° C, 4 hours)

Tensile strength [kg / cm ² ) 174 212 196 132 130 Elongation [%] 360 340 340 320 330

100% tensile stress [kg / cm ² ] 51 56 58 53 37 Hardness (JISA) 72 72 71 71 71 Compression set

1 50 ° C, 70 hours [%] 42 40 38 56 38

As can be seen from Table 4, the tensile strength was higher when the modifier of the present invention was used (Examples 10 to 12) than when the modifier composed of H—NBR was used (Comparative Example 6). It can be seen that the compression set becomes small.

Example 13 (Modification of acrylonitrile-butadiene rubber)

30 parts of the modifier obtained in Example 3, 70 parts of NBR [acrylonitrile butadiene copolymer rubber, DN 101, viscosity of 781-2, bound acrylonitrile amount of 42%, manufactured by Zeon Corporation], 5 parts of zinc white, 1 part of stearic acid, 60 parts of Ribonbon black (SRF), 10 parts of plasticizer (Chocol TP-95, manufactured by Choco Chemical) 0.5 part of sulfur (Mesh 325), tetra 1.5 parts of methylthiuram disulfide, 1 part of N-cyclohexyl-2-benzothiazyl sulfonamide, 1 part of anti-aging agent (Naugard 445, manufactured by Haicules) and 1 part One part of the agent (Nocrack MB Z, Ouchi Shinko Co., Ltd.) was mixed with a roll to obtain a rubber composition. This rubber composition was crosslinked. Table 5 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Examples 14 to 15 and Comparative Examples 8 to 9

A rubber composition and a crosslinked product were obtained in the same manner as in Example 13, except that the modifier and NBR used in Example 13 were changed to those having the compounding formulations shown in Table 5. Table 5 shows the results.

Table 5 Example Comparative example

13 14 15 8 9 Formulation [Parts]

Modifier

Carboxylated H— NB R 3 30 50 70--

H-NBR---50 Rubber

NBR 70 50 30 50 100 Tensile test

(Crosslinking: 1 60 ° C, 20 minutes)

Tensile strength [kg / cm ² ) 198 237 248 176 155 Elongation [%] 380 380 390 430 360

100% tensile stress [kg / cm ² ] 48 57 58 36 32 Hardness (JISA) 66 69 67 65 63 Tear test [kg / cm] 40 46 51 37 35 Compression set

1 50 ° C, 70 hours [%] 14 24 28 32 9 Low temperature compression set

— 20 ° C, 70 hours [%] 38 45 53 56 32 Compression rate 25%

(Crosslinking: 1 60 ° C, 20 minutes)

1 50 ° C, 70 hours [%] 43 56 69 77 27

From Table 5, the tensile strength and tensile stress were higher when the modifier of the present invention was used (Examples 13 to 15) than when the modifier composed of H—NBR was used (Comparative Example 8). It can be seen that the tensile strength increases and the compression set (at room temperature and low temperature) decreases.

Example 16 (Modification of fluororubber)

30 parts of the modifier obtained in Example 1, 70 parts of fluororubber (Viton GF, manufactured by Dubon), 30 parts of carbon black (SFR), 3 parts of triarylsocyanate (TA IC), 3 parts of lead oxide (P bO) 3 parts and 1,3-bis (3-butylvinyloxyisopropyl) benzene (3 parts) (Valcup 40KE, manufactured by Hercules) were mixed with a roll to obtain a rubber composition. This rubber composition was crosslinked. Table 6 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Examples 17 to 18 and Comparative Example 10: L 1

A rubber composition and a crosslinked product were obtained in the same manner as in Example 16, except that the modifier and the fluororubber used in Example 16 were changed to those having the compounding recipe shown in Table 6. Table 6 shows the results.

Table 6

From Table 6, it can be seen that the tensile strength and the rebound resilience were higher when the modifier of the present invention was used (Examples 16 to 18) than when the modifier composed of H—NBR was used (Comparative Example 10). And the compression set becomes small. Example 19 (Modification of hydrogenated acrylonitrile-butadiene rubber)

50 parts of the modifier obtained in Example 1, 50 parts of H-NBR, 40 parts of Riki-bon black (FEF Riki-bon Asahi 60, manufactured by Asahi Carbon Co., Ltd.), 5 parts of zinc white and 1,3-bis (3 —Butyl propyl isopropyl) benzene (Burka ,,,, The mixture was mixed with a roll to obtain a rubber composition. This rubber composition was crosslinked. Table 7 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Comparative Example 1 2

A rubber composition and a crosslinked product were obtained in the same manner as in Example 19, except that the modifier and H—NBR used in Example 19 were changed to those having the compounding formulations shown in Table 7. Table 7 shows the results.

Example 20

50 parts of the modifier obtained in Example 1, 50 parts of H-NBR, 40 parts of Riki Bon Black (FEF Riki Bon Asahi 60, manufactured by Asahi Carbon Co., Ltd.), 5 parts of zinc oxide, 5 parts of sulfur ( 32.5 mesh) 0.5 part, 1 part of stearic acid, 1.5 parts of tetramethylthiuram disulfide and 1 part of N-cyclohexyl-12-benzothiazyl disulfide amide are mixed with a roll, and rubber is mixed. A composition was obtained. This rubber composition was crosslinked. Table 7 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Comparative Example 1 3

A rubber composition and a crosslinked product were obtained in the same manner as in Example 20, except that the modifier and H-NBR used in Example 20 were changed to those having the compounding formulations shown in Table 7. Table 7 shows the results.

Table 7 Example Comparative example

19 20 12 13 Formulation [Parts]

Modifier

Carboxylated H— NBR 1 50 50 I-Rubber

H-N BR 50 50 100 100 Tensile test 25 ° C measurement

(Po crosslinking: 170 ° C, 20 minutes)

Sulfur crosslinking: 1 50 ° C, 30 minutes)

Tensile strength [kg / cm ² ) 304 315 274 234 Elongation [%] 410 410 450 470

100% tensile stress [kg / cm ² ] 53 56 38 37 Hardness (JISA) 71 73 69 70 Tensile test 1 50 ° C measurement

(Po crosslinking: 170 ° C, 20 minutes)

Sulfur bridge: 150, 30 minutes)

Tensile strength [kg / cm ² ) 88 78 65 51 Elongation [%] 160 150 130 150

100% tensile stress [kg / cm ² ] 56 53 44 39 Pico abrasion test

Abrasion loss [xl (T ⁴ cc) 38 32 62 56 Maintenance adhesion test

Surface treated nylon fiber [N / 25mm] 290 300 230 270 Surface treated glass fiber [N / 25 marauder] 310 315 250 280 Untreated nylon fiber [N / 25 related] 145 150 80 95 From Table 7, when the modifier of the present invention is blended (Examples 19 to 20), the tensile strength and the tensile stress are lower at room temperature and at higher temperatures than when the modifier is not blended (Comparative Examples 12 to 13). It can be seen that in each case, the wear increases and the wear loss decreases. Furthermore, it can be seen that the adhesive strength with the fiber is increased. Example 21 (Hydrogen rubber modification)

Hydrol rubber (Gechron 2000, manufactured by Zeon Corporation) 100 parts, silica (Carplex 1120) 40 parts, magnesium oxide (# 150) 10 parts, lubricant (Gredda G8205) 1 part, antioxidant (Naugai 1) 445) 1. 5 parts, anti-aging agent (Nocrack 224, manufactured by Ouchi Shinko Co., Ltd.) 1.5 parts, crosslinking agent (Disnet F, manufactured by Nippon Zeon Co., Ltd.) 0.9 part and silane coupling agent (A— 172, 1 part of vinyl tris (; 5-methoxy) silane, manufactured by Pokki-Ichi Chemicals Co., Ltd. was kneaded with a roll to obtain Formulation A (100 parts of the modifier obtained in Example 1, Silica (Carplex 112 0) 40 parts, zinc stearate 2 parts, zinc oxide 5 parts, antioxidant (Nowgard 445) 1.5 parts, antioxidant (Nocrack 224) 1.5 parts, silica cutting agent (A-172) 1 part and 1,3-bis (3-butylperoxyisopropyl) Seven parts of Nzen (Valcup 40KE, manufactured by Hercules) were kneaded with a roll to obtain Compound C.

70 parts of compound A and 30 parts of compound C were mixed with a roll to obtain a rubber composition. This rubber composition was crosslinked. Table 8 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Comparative Example 14

H—100 parts NBR, 40 parts silica (Carplex 1120), 2 parts zinc stearate, 5 parts zinc oxide, antioxidant (Nowgard 445) 1.5 parts, anti-aging agent (Nocrack 224) 1.5 parts, silica coupling agent (A-172) 1 part and 1,3-bis (3-butylvinyloxysopropyl) benzene (Valcup 40KE, Hercules) Was kneaded with a roll to obtain Compound B.

70 parts of the compound A and 30 parts of the compound B were mixed with a roll to obtain a rubber composition. This rubber composition was crosslinked. Table 8 shows the evaluation results of the rubber composition and the crosslinked product thereof.

Example 22

A rubber composition and a crosslinked product were obtained in the same manner as in Example 21, except that the amounts of the compound A and the compound C used in Example 21 were changed to those shown in Table 8. Table 8 shows the results.

Comparative Examples 15-16

A rubber composition and a crosslinked product were obtained in the same manner as in Comparative Example 14, except that the amounts of the compound A and the compound B used in Comparative Example 14 were changed to those shown in Table 8. Table 8 shows the results.

Table 8

From Table 8, it can be seen that the composition C containing the modifier of the present invention was used in comparison with the case of using the composition B containing the modifier composed of H-NBR (Comparative Examples 14 to 15). In the case (Examples 22 to 23), it can be seen that the roll workability was good, the tensile stress was high, and the volume change rate in the oil resistance test was small. The invention's effect

ADVANTAGE OF THE INVENTION According to the modifier of this invention, the tensile strength, the tensile stress, etc. of the rubber composition with which it was compounded become large, and the characteristics, such as oil resistance and abrasion resistance, are also improved.

Since the modifier of the present invention and the rubber composition containing the same have the above-mentioned excellent properties, they can be used for ink printing rolls, electrostatic image forming apparatus openings, Rolls such as paper feed rolls; hoses or tubes such as automotive power steering hoses, hydraulic hoses, and fuel hoses; belts such as belts, poly-V belts, and toothed transmission belts; tires; wire coating materials; sponges; Moldings or composites such as; damping material (vibration-proof material); spring material

Suitable for applications such as anti-friction materials; seal materials such as 0-rings, gaskets, oil seals and freon seals; sliding materials (friction materials) such as clutch plates and brakes for automobiles; .

Claims

The scope of the claims

1. acid equivalent is 1 X 10_ ⁴ ephr above, arm one hundred twenty-one viscosity _{(ML 1 + 4, 1 00} ° C) is 15 to 200 and carboxylation of 80 or less iodine value two preparative drill group-containing highly saturated copolymer heavy A rubber composition characterized by containing a combined rubber and another rubber.

2. acid equivalent is 1 X 10- ⁴ ephr above, in the infrared absorption analysis [peak height of the force carboxylic acid anhydride group] Z ([peak height of a carboxylic acid anhydride group] + [peak height of a carboxyl group]) is 0.5 or more, arm one hundred twenty-one viscosity _{(ML 1+ 4, 100 ° C} ) is 15 to 200 and an iodine value of 80 or less of the carboxyl nitrile group-containing highly saturated copolymer rubber, as well as other rubber, A rubber composition comprising:

3. acid equivalent is 1 X 10- ⁴ ephr above, arm one knee viscosity _{(ML 1 + 4, 1 00} ° C) is 15 to 200 and carboxylation of 80 or less iodine value two preparative drill group-containing highly saturated copolymer heavy A strength modifier for rubber, comprising a united rubber.

4. acid equivalent is 1 X 10- ⁴ ephr above, [high force peaks carboxylic acid anhydride group] in the infrared absorption analysis / ([peak height of a carboxylic acid anhydride group] + [peak height of a carboxyl group]) is 0.5 or more, characterized by comprising a highly saturated copolymer rubber having a carboxylated nitrile group having a viscosity of 15 to 200 (ML ι ₊ 4, 100 ° C) and an iodine value of 80 or less. Strength modifier for rubber.