JP6113402B2 - Nitrile rubber composition and rubber cross-linked product - Google Patents

Description

  The present invention provides a nitrile rubber composition that has excellent processability, is excellent in normal physical properties and cold resistance, and can give a rubber cross-linked product with little change in physical properties even when used in contact with oil, And a crosslinked rubber obtained using the nitrile rubber composition.

  Nitrile rubber (acrylonitrile-butadiene copolymer rubber) has been used as a material for automotive rubber parts such as hoses and tubes, taking advantage of oil resistance, mechanical properties, chemical resistance, etc. Hydrogenated nitrile rubber (hydrogenated acrylonitrile-butadiene copolymer rubber) in which carbon-carbon double bonds in the polymer main chain of rubber are hydrogenated is further excellent in heat resistance, so rubber parts such as seals, belts, hoses, diaphragms, etc. Is used.

  As such a nitrile rubber composition, for example, in Patent Document 1, a hydrogenated nitrile rubber having a α, β-ethylenically unsaturated dicarboxylic acid monoester monomer unit, a polyamine-based crosslinking agent, and a basic crosslinking accelerator are disclosed. A nitrile rubber composition containing benzene has been proposed. In Patent Document 1, a plasticizer is used in order to improve the processability of the nitrile rubber composition and the normal physical properties and cold resistance when the crosslinked product is used. However, when a plasticizer is added to the nitrile rubber composition in this way, the processability, normal physical properties, and cold resistance are improved, but the application to contact with oil (for example, belts and hoses for automobile parts, When used for a seal or the like, there is a problem that physical properties (for example, hardness and cold resistance) of the crosslinked product are lowered.

JP 2001-55471 A

  The present invention is a rubber cross-linked product having excellent processability, excellent in normal physical properties and cold resistance, and having little change in physical properties (for example, changes in hardness and cold resistance) even when used in contact with oil. It is an object of the present invention to provide a nitrile rubber composition capable of providing the above and a crosslinked rubber obtained using the nitrile rubber composition.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by a nitrile rubber composition obtained by blending a reactive silicone oil with a carboxyl group-containing nitrile rubber. It came to complete.

That is, according to the present invention, a nitrile rubber composition containing a carboxyl group-containing nitrile rubber and a reactive silicone oil , wherein the carboxyl group-containing nitrile rubber is α, There is provided a nitrile rubber composition containing a β-ethylenically unsaturated dicarboxylic acid monoester monomer unit in a proportion of 0.1 to 20% by weight .

In the nitrile rubber composition of the present invention, the iodine value of the carboxyl group-containing nitrile rubber is preferably 120 or less.
The carboxyl group-containing nitrile rubber is composed of 5 to 60% by weight of α, β-ethylenically unsaturated nitrile monomer unit and 0.1 to 20% by weight of α, β-ethylenically unsaturated dicarboxylic acid monoester monomer unit. And 15 to 94.9% by weight of conjugated diene monomer units.
It is preferable that the reactive silicone oil has at least one reactive group selected from the group consisting of a hydroxyl group, an amino group, a mercapto group, an epoxy group, a carboxyl group, an acrylic group, and a methacryl group.
The nitrile rubber composition of the present invention preferably further contains silica.
Moreover, it is preferable that the nitrile rubber composition of this invention further contains a polyamine type crosslinking agent.

  Moreover, according to this invention, the rubber crosslinked material formed by bridge | crosslinking the said nitrile rubber composition is provided. The rubber cross-linked product is preferably a sealing material, a belt, a hose or a gasket.

  According to the present invention, rubber having excellent processability, excellent normal physical properties and cold resistance, and little physical property change (for example, change in hardness and cold resistance) even when used in contact with oil A nitrile rubber composition capable of providing a crosslinked product, and a rubber crosslinked product obtained by crosslinking the nitrile rubber composition can be provided.

Nitrile rubber composition The nitrile rubber composition of the present invention comprises a carboxyl group-containing nitrile rubber and a reactive silicone oil.

Carboxyl group-containing nitrile rubber First, the carboxyl group-containing nitrile rubber used in the present invention will be described. The carboxyl group-containing nitrile rubber used in the present invention is a copolymer of an α, β-ethylenically unsaturated nitrile monomer, a carboxyl group-containing monomer, and other copolymerizable monomers added as necessary. It is the rubber obtained by this.

  The α, β-ethylenically unsaturated nitrile monomer is not particularly limited as long as it is an α, β-ethylenically unsaturated compound having a nitrile group. For example, acrylonitrile; α-chloroacrylonitrile, α-bromoacrylonitrile, etc. [Alpha] -halogenoacrylonitrile; [alpha] -alkylacrylonitrile such as methacrylonitrile; and the like. Among these, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable. The α, β-ethylenically unsaturated nitrile monomer may be used alone or in combination of two or more.

  The content of the α, β-ethylenically unsaturated nitrile monomer unit is preferably 5 to 60% by weight, more preferably 10 to 55% by weight, and still more preferably 15 to 50% based on the total monomer units. % By weight. If the content of the α, β-ethylenically unsaturated nitrile monomer unit is too small, the oil resistance of the resulting rubber cross-linked product may be reduced, and conversely if too much, cold resistance may be reduced. is there.

  The carboxyl group-containing monomer can be copolymerized with an α, β-ethylenically unsaturated nitrile monomer and has at least one unsubstituted (free) carboxyl group that is not esterified. If it is a monomer, it will not specifically limit. By using a carboxyl group-containing monomer, a carboxyl group can be introduced into the nitrile rubber.

  Examples of the carboxy group-containing monomer used in the present invention include α, β-ethylenically unsaturated monocarboxylic acid monomers, α, β-ethylenically unsaturated polycarboxylic acid monomers, and α, β -Ethylenically unsaturated dicarboxylic acid monoester monomer and the like. The carboxyl group-containing monomer also includes monomers in which the carboxyl group of these monomers forms a carboxylate. Furthermore, an anhydride of α, β-ethylenically unsaturated polyvalent carboxylic acid can also be used as a carboxyl group-containing monomer because it forms a carboxyl group by cleaving the acid anhydride group after copolymerization.

  Examples of the α, β-ethylenically unsaturated monocarboxylic acid monomer include acrylic acid, methacrylic acid, ethyl acrylic acid, crotonic acid, and cinnamic acid.

  Examples of the α, β-ethylenically unsaturated polyvalent carboxylic acid monomer include butenedionic acid such as fumaric acid and maleic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, allylmalonic acid, and teraconic acid. Examples of the anhydride of α, β-unsaturated polyvalent carboxylic acid include maleic anhydride, itaconic anhydride, and citraconic anhydride.

  As the α, β-ethylenically unsaturated dicarboxylic acid monoester monomer, maleic acid monoalkyl esters such as monomethyl maleate, monoethyl maleate, monopropyl maleate, mono n-butyl maleate; monocyclopentyl maleate, Maleic acid monocycloalkyl esters such as monocyclohexyl maleate and monocycloheptyl maleate; Monoalkyl cycloalkyl esters of maleic acid such as monomethylcyclopentyl maleate and monoethylcyclohexyl maleate; Monomethyl fumarate, monoethyl fumarate and monofumarate Monoalkyl esters of fumaric acid such as propyl and mono-n-butyl fumarate; mono-fumaric acid such as monocyclopentyl fumarate, monocyclohexyl fumarate and monocycloheptyl fumarate Cycloalkyl esters; fumaric acid monoalkyl cycloalkyl esters such as monomethylcyclopentyl fumarate and monoethylcyclohexyl fumarate; citraconic acid monoalkyl esters such as monomethyl citraconic acid, monoethyl citraconic acid, monopropyl citraconic acid and mono n-butyl citraconic acid Citraconic acid monocycloalkyl ester such as citraconic acid monocyclopentyl, citraconic acid monocyclohexyl, citraconic acid monocycloheptyl, etc .; citraconic acid monomethylcyclopentyl, citraconic acid monoethylcyclohexyl citraconic acid monoalkyl cycloalkyl ester; Monoalkyl itaconate such as monoethyl acrylate, monopropyl itaconate, mono n-butyl itaconate Esters; itaconic acid monocyclopentyl, itaconic acid monocyclohexyl, itaconic acid monocycloheptyl, etc. itaconic acid monocycloalkyl ester; itaconic acid monomethylcyclopentyl, itaconic acid monoethylcyclohexyl, etc. .

  A carboxyl group-containing monomer may be used alone or in combination of two or more. Among these, α, β-ethylenically unsaturated dicarboxylic acid monoester monomer is preferable, maleic acid monoalkyl ester is more preferable, and mono n-butyl maleate is preferable because the effects of the present invention become more remarkable. Is particularly preferred. In addition, as for carbon number of the alkyl group of the said maleic acid monoalkyl ester, 2-8 are preferable.

  The content of the carboxyl group-containing monomer unit is preferably from 0.1 to 20% by weight, more preferably from 0.2 to 15% by weight, and even more preferably from 0.5 to 10%, based on all monomer units. % By weight. If the content of the carboxyl group-containing monomer unit is too small, the mechanical strength and compression set resistance of the resulting rubber cross-linked product may be deteriorated. On the other hand, if the content is too large, the nitrile rubber composition scorch will be deteriorated. There is a possibility that the stability deteriorates or the fatigue resistance of the obtained rubber cross-linked product is lowered.

  In addition, the carboxyl group-containing nitrile rubber used in the present invention is a conjugate from the point that the resulting crosslinked product exhibits rubber elasticity together with the α, β-ethylenically unsaturated nitrile monomer and the carboxyl group-containing monomer. It is preferable to copolymerize a diene monomer.

  Examples of the conjugated diene monomer that forms the conjugated diene monomer unit include 4-carbon atoms such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and chloroprene. 6 conjugated diene monomers are preferred, 1,3-butadiene and isoprene are more preferred, and 1,3-butadiene is particularly preferred. The conjugated diene monomer may be used alone or in combination of two or more.

  The content of the conjugated diene monomer unit is preferably from 15 to 94.9% by weight, more preferably from 20 to 89.8% by weight, and even more preferably from 25 to 84.5% by weight based on the total monomer units. %. If the content of the conjugated diene monomer unit is too small, the rubber elasticity of the resulting rubber cross-linked product may be lowered. Conversely, if the content is too large, the heat resistance and chemical stability may be impaired. . In addition, content of the said conjugated diene monomer unit is content also including the hydrogenated part, when hydrogenation mentioned later is performed.

  In addition, the carboxyl group-containing nitrile rubber used in the present invention includes an α, β-ethylenically unsaturated nitrile monomer, a carboxyl group-containing monomer, and a conjugated diene monomer, as well as other monomers copolymerizable therewith. It may be a copolymer of a monomer. Examples of such other monomers include ethylene, α-olefin monomer, aromatic vinyl monomer, α, β-ethylenically unsaturated carboxylic acid ester monomer (the above-mentioned “carboxyl group-containing single monomer”). Excluding those corresponding to “body”), fluorine-containing vinyl monomers, copolymerizable anti-aging agents and the like.

  The α-olefin monomer preferably has 3 to 12 carbon atoms, and examples thereof include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene.

  Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyl pyridine and the like.

  Examples of the α, β-ethylenically unsaturated carboxylic acid ester monomer include carbon numbers such as methyl acrylate, ethyl acrylate, n-butyl acrylate, n-dodecyl acrylate, methyl methacrylate, and ethyl methacrylate. (Meth) acrylic acid ester having 1 to 18 alkyl groups (abbreviation of “methacrylic acid ester and acrylic acid ester”; the same shall apply hereinafter); carbon number such as methoxymethyl acrylate, methoxyethyl acrylate, methoxyethyl methacrylate (Meth) acrylic acid ester having 2 to 12 alkoxyalkyl groups; (meth) acrylic having 2 to 12 carbon number cyanoalkyl groups such as α-cyanoethyl acrylate, α-cyanoethyl methacrylate, α-cyanobutyl methacrylate, etc. Acid ester; 2-hydroxyethyl acrylate (Meth) acrylic acid ester having a C1-C12 hydroxyalkyl group such as 2-hydroxypropyl acrylate and 2-hydroxyethyl methacrylate; 1 carbon atom such as trifluoroethyl acrylate and tetrafluoropropyl methacrylate (Meth) acrylic acid ester having -12 fluoroalkyl groups; α, β-ethylenically unsaturated dicarboxylic acid dialkyl ester such as dimethyl maleate, dimethyl fumarate, dimethyl itaconate, diethyl itaconate; dimethylaminomethyl acrylate, And dialkylamino group-containing α, β-ethylenically unsaturated carboxylic acid esters such as diethylaminoethyl acrylate.

  Examples of the fluorine-containing vinyl monomer include fluoroethyl vinyl ether, fluoropropyl vinyl ether, o-trifluoromethyl styrene, vinyl pentafluorobenzoate, difluoroethylene, and tetrafluoroethylene.

  Examples of copolymerizable anti-aging agents include N- (4-anilinophenyl) acrylamide, N- (4-anilinophenyl) methacrylamide, N- (4-anilinophenyl) cinnamamide, N- (4- Anilinophenyl) crotonamide, N-phenyl-4- (3-vinylbenzyloxy) aniline, N-phenyl-4- (4-vinylbenzyloxy) aniline and the like.

  These other copolymerizable monomers may be used in combination. The content of other monomer units is preferably 50% by weight or less, more preferably 30% by weight or less, and still more preferably 10% by weight or less based on the total monomer units.

  The iodine value of the carboxyl group-containing nitrile rubber is preferably 120 or less, more preferably 60 or less, still more preferably 40 or less, and particularly preferably 30 or less. By setting the iodine value to 120 or less, the heat resistance and ozone resistance of the resulting rubber cross-linked product can be improved.

The polymer Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the carboxyl group-containing nitrile rubber is preferably 10 to 200, more preferably 15 to 150, still more preferably 15 to 100, and particularly preferably 30 to 70. If the polymer Mooney viscosity of the carboxyl group-containing nitrile rubber is too low, the mechanical properties of the resulting rubber cross-linked product may be reduced. Conversely, if it is too high, the processability of the nitrile rubber composition may be reduced. .

The carboxyl group content in the carboxyl group-containing nitrile rubber, that is, the number of moles of carboxyl groups per 100 g of the carboxyl group-containing nitrile rubber is preferably 5 × 10 ^{−4 to} 5 × 10 ⁻¹ ephr, more preferably 1. × 10 ⁻³ to 1 × 10 ⁻¹ ephr, particularly preferably 5 × 10 ^{−3 to} 6 × 10 ⁻² ephr. If the carboxyl group content of the carboxyl group-containing nitrile rubber is too low, the mechanical strength of the resulting rubber cross-linked product may be reduced, and if it is too high, cold resistance may be reduced.

  The method for producing the carboxyl group-containing nitrile rubber of the present invention is not particularly limited, but a latex of copolymer rubber is prepared by copolymerizing the above monomers by emulsion polymerization using an emulsifier, and this is hydrogenated. It is preferable to manufacture by this. In emulsion polymerization, commonly used polymerization auxiliary materials such as emulsifiers, polymerization initiators, molecular weight regulators and the like can be used.

  Although it does not specifically limit as an emulsifier, For example, nonionic emulsifiers, such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester; myristic acid, palmitic acid, oleic acid And anionic emulsifiers such as salts of fatty acids such as linolenic acid, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, higher alcohol sulfates, and alkyl sulfosuccinates; sulfoesters of α, β-unsaturated carboxylic acids, α , Β-unsaturated carboxylic acid sulfate esters, sulfoalkyl aryl ethers and other copolymerizable emulsifiers. The amount of the emulsifier used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the total monomers.

  The polymerization initiator is not particularly limited as long as it is a radical initiator, but inorganic peroxides such as potassium persulfate, sodium persulfate, ammonium persulfate, potassium perphosphate, hydrogen peroxide; t-butyl peroxide, cumene Hydroperoxide, p-menthane hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, dibenzoyl peroxide, 3, 5, 5 Organic peroxides such as trimethylhexanoyl peroxide and t-butylperoxyisobutyrate; azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, etc. Azotization Ones; and the like. These polymerization initiators can be used alone or in combination of two or more. As the polymerization initiator, an inorganic or organic peroxide is preferable. When a peroxide is used as the polymerization initiator, it can be used as a redox polymerization initiator in combination with a reducing agent such as sodium bisulfite or ferrous sulfate. The amount of the polymerization initiator used is preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the total monomers.

  The molecular weight modifier is not particularly limited, but mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, methylene bromide; α-methylstyrene dimer And sulfur-containing compounds such as tetraethylthiuram disulfide, dipentamethylene thiuram disulfide, and diisopropylxanthogen disulfide. These can be used alone or in combination of two or more. Among these, mercaptans are preferable, and t-dodecyl mercaptan is more preferable. The amount of the molecular weight modifier used is preferably 0.1 to 0.8 parts by weight with respect to 100 parts by weight of all monomers.

  Usually, water is used as a medium for emulsion polymerization. The amount of water is preferably 80 to 500 parts by weight with respect to 100 parts by weight of the total monomers.

  In the emulsion polymerization, polymerization auxiliary materials such as a stabilizer, a dispersant, a pH adjuster, an oxygen scavenger, and a particle size adjuster can be used as necessary. In using these, neither the kind nor the usage-amount is specifically limited.

  When the iodine value of the copolymer obtained by copolymerization is higher than 120, the copolymer may be hydrogenated (hydrogenation reaction) so that the iodine value is 120 or less. In this case, the hydrogenation method is not particularly limited, and a known method may be employed.

Reactive Silicone Oil The reactive silicone oil used in the present invention is a silicone oil having a reactive group and acts as a plasticizer in the nitrile rubber composition of the present invention. The reactive silicone oil used in the present invention forms a chemical bond with the carboxyl group-containing nitrile rubber when the nitrile rubber composition is crosslinked to form a crosslinked rubber.

  Therefore, in the present invention, by adding a reactive silicone oil, the nitrile rubber composition can act as a plasticizer due to its action as a plasticizer, and can impart excellent processability. . In addition, the reactive silicone oil used in the present invention forms a chemical bond with the carboxyl group-containing nitrile rubber when the nitrile rubber composition is crosslinked to form a rubber crosslinked product. In this case, even when used in contact with oil, it has a property that elution from the crosslinked rubber hardly occurs. Therefore, by blending reactive silicone oil, even when used in contact with oil, the plasticizing action by reactive silicone oil can be kept good, and even when used in contact with oil. Changes in physical properties (for example, changes in hardness and cold resistance) can be minimized.

The reactive group contained in the reactive silicone oil used in the present invention is preferably a functional group capable of reacting with the carboxyl group constituting the carboxyl group-containing nitrile rubber. Examples of such a reactive group include a hydroxyl group, an amino group, a mercapto group, an epoxy group, a carboxyl group, an acrylic group (—OOC—CH═CH ₂ , where —OOC— represents an oxycarbonyl group), and a methacryl group ( Those having at least one selected from the group consisting of —OOC—C (CH ₃ ) ═CH ₂ , wherein —OOC— represents an oxycarbonyl group are preferable, and among these, an amino group, an epoxy group, A mercapto group and a carboxyl group are more preferable, and an amino group is particularly preferable. The epoxy group is not particularly limited as long as it is a group having an oxirane ring. For example, a linear hydrocarbon group having an oxirane ring or a cyclic hydrocarbon group having an oxirane ring. Etc. can also be used.

（上記式（１）中、Ｒ^１は、炭素数１〜３０、好ましくは炭素数１〜１０の主鎖中および／または側鎖中にヘテロ原子を有していてもよい炭化水素基、Ｘ^１は、上述したいずれかの反応性基、ｍは、１〜１０，０００の整数、ｎは、１〜１０，０００の整数である。）

（上記式（２）中、Ｒ^２、Ｒ^３は、それぞれ独立して、炭素数１〜３０、好ましくは炭素数１〜１０の主鎖中および／または側鎖中にヘテロ原子を有していてもよい炭化水素基、Ｘ^２、Ｘ^３は、それぞれ独立して、上述したいずれかの反応性基、ｐは、１〜１０，０００の整数である。Ｒ^２、Ｒ^３は同一でもよいし、互いに異なっていてもよい。また、Ｘ^２、Ｘ^３は同一でもよいし、互いに異なっていてもよい。）

（上記式（３）中、Ｒ^４、Ｒ^５、Ｒ^６は、それぞれ独立して、炭素数１〜３０、好ましくは炭素数１〜１０の主鎖中および／または側鎖中にヘテロ原子を有していてもよい炭化水素基、Ｘ^４、Ｘ^５、Ｘ^６は、それぞれ独立して、上述したいずれかの反応性基、ｑは、１〜１０，０００の整数、ｒは、１〜１０，０００の整数である。Ｒ^４、Ｒ^５、Ｒ^６は同一でもよいし、互いに異なっていてもよい。また、Ｘ^４、Ｘ^５、Ｘ^６は同一でもよいし、互いに異なっていてもよい。）

（上記式（４）中、Ｒ^７は、炭素数１〜３０、好ましくは炭素数１〜１０の主鎖中および／または側鎖中にヘテロ原子を有していてもよい炭化水素基、Ｘ^７は、上述したいずれかの反応性基、ｓは、１〜１０，０００の整数である。）

（上記式（５）中、Ｒ^８、Ｒ^９は、それぞれ独立して、炭素数１〜３０、好ましくは炭素数１〜１０の主鎖中および／または側鎖中にヘテロ原子を有していてもよい炭化水素基、Ｘ^８、Ｘ^９は、それぞれ独立して、上述したいずれかの反応性基、ｔは、１〜１０，０００の整数、ｕは、１〜１０，０００の整数である。Ｒ^８、Ｒ^９は同一でもよいし、互いに異なっていてもよい。また、Ｘ^８、Ｘ^９は同一でもよいし、互いに異なっていてもよい。）

（上記式（６）中、Ｒ^２、Ｒ^３、ｐは、それぞれ上記式（２）と同様。） The reactive silicone oil used in the present invention is, for example, the following general formula (1), the following general formula (2), the following general formula (3), the following general formula (4), the following general formula (5), or the following What is represented by General formula (6) can be used. Among these, what is represented by the following general formula (2) is preferable, the reactivity is high, and when blended in a nitrile rubber composition, it can act well as a cross-linking agent. What is represented by General formula (6) is especially preferable.

(In the above formula (1), R ¹ is a hydrocarbon group having 1 to 30 carbon atoms, preferably a C ¹ to C 10 main chain and / or a side chain optionally having a hetero atom, X ¹ is any of the reactive groups described above, m is an integer of 1 to 10,000, and n is an integer of 1 to 10,000.)

(In the above formula (2), R ² and R ³ each independently have a hetero atom in the main chain and / or side chain having 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms. And the hydrocarbon group, X ² and X ³ may each independently represent any of the reactive groups described above, p is an integer of 1 to 10,000, and R ² and R ³ may be the same. And X ² and X ³ may be the same or different from each other.)

(In the above formula (3), R ⁴ , R ⁵ and R ⁶ are each independently a hetero atom in the main chain and / or side chain having 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms. The hydrocarbon group which may have, X ⁴ , X ⁵ and X ⁶ are each independently any of the reactive groups described above, q is an integer of 1 to 10,000, and r is 1 to It is an integer of 10,000, R ⁴ , R ⁵ , R ⁶ may be the same or different from each other, and X ⁴ , X ⁵ , X ⁶ may be the same or different from each other. Good.)

(In the above formula (4), R ⁷ is a hydrocarbon group having 1 to 30 carbon atoms, preferably a C 1-10 main chain and / or a side chain optionally having a hetero atom, X ⁷ is one of the reactive groups described above, and s is an integer of 1 to 10,000.)

(In the above formula (5), R ⁸ and R ⁹ each independently have a hetero atom in the main chain and / or the side chain having 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms. may also be a hydrocarbon ^group, X 8, ^{X 9} are each independently one of the reactive groups described above, t is an integer of 1 to 10,000, u is an integer of 1 to 10,000 R ⁸ and R ⁹ may be the same or different from each other, and X ⁸ and X ⁹ may be the same or different from each other.

(In the above formula (6), R ² , R ³ and p are the same as in the above formula (2).)

When R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and / or R ⁹ have a hetero atom in the main chain and / or side chain As the hetero atom, an oxygen atom, a sulfur atom and a nitrogen atom are preferable, and an oxygen atom is particularly preferable.

  The reactive silicone oil represented by the above formula (1) is a side chain type reactive group-modified silicone oil having a reactive group in the side chain, and is represented by the above formula (2) and formula (6). The reactive silicone oil is a both-end type reactive group-modified silicone oil having reactive groups at both ends, and the reactive silicone oil represented by the above formula (3) is reactive on the side chain and both ends. A reactive group-modified silicone oil having a side chain at both ends, and the reactive silicone oil represented by the above formula (4) is a one-end type reactive group-modified silicone oil having a reactive group at one end In addition, the reactive silicone oil represented by the above formula (5) is a side chain one-end type reactive group-modified silicone oil having a reactive group at the side chain and one end.

  In addition, as the reactive silicone oil represented by the above formula (1), trade names “KF-868”, “KF-859”, “KF-102”, “KF-1001”, “KF-2001”, "X-22-3701E", "X-22-4741" (both manufactured by Shin-Etsu Chemical Co., Ltd.) and the like are commercially available, and such commercially available products can be used. As the reactive silicone oil represented by the above formula (2), trade names “X-22-161B”, “X-22-162C”, “X-22-163B”, “X-22-164B”, “X-22-167B”, “X-22-169B”, “X-22-4952” (all manufactured by Shin-Etsu Chemical Co., Ltd.) and the like are commercially available. it can. Moreover, as reactive silicone oil represented by the said Formula (3), it is marketed as brand name "KF-857", "X-22-9002" (all are the Shin-Etsu Chemical Co., Ltd. make), etc., Such commercially available products can be used. Furthermore, as the reactive silicone oil represented by the above (4), trade names “X-22-173DX”, “X-22-170DX”, “X-22-174DX”, “X-22-176DX” , “X-22-3710” (all manufactured by Shin-Etsu Chemical Co., Ltd.) and the like, and such commercially available products can be used.

The weight average molecular weight of the reactive silicone oil is preferably 200 to 100,000, more preferably 200 to 50,000, still more preferably 200 to 20,000. If the weight average molecular weight of the reactive silicone oil is too low, the effect of adding the reactive silicone oil may be reduced. On the other hand, if the weight is too large, the viscosity of the reactive silicone oil becomes high and handling is difficult. There is a risk.
The kinematic viscosity (20 ° C., unit: mm ² / s) of the reactive silicone oil is preferably 10 to 10,000, more preferably 20 to 1,000, and particularly preferably 20 to 500.

  Moreover, the compounding quantity of the reactive silicone oil in the nitrile rubber composition of this invention becomes like this. Preferably it is 0.1-200 weight part with respect to 100 weight part of carboxyl group-containing nitrile rubber, More preferably, it is 0.5- 100 parts by weight, more preferably 5 to 60 parts by weight. If the amount of the reactive silicone oil is too small, it will be difficult to obtain the effect of blending the reactive silicone oil. On the other hand, if the amount is too large, the physical properties (for example, strength and elongation) of the resulting rubber cross-linked product will be reduced. There is a fear.

  The nitrile rubber composition of the present invention may contain a crosslinking agent. Although it does not specifically limit as a crosslinking agent, Although a sulfur type crosslinking agent, an organic peroxide type crosslinking agent, a polyamine type crosslinking agent, etc. are mentioned, Among these, an organic peroxide type crosslinking agent, a polyamine type crosslinking agent are mentioned. Are preferred, and polyamine crosslinking agents are more preferred.

  As the organic peroxide-based crosslinking agent, conventionally known ones can be used. Dicumyl peroxide, cumene hydroperoxide, t-butylcumyl peroxide, paramentane hydroperoxide, di-t-butyl peroxide, 1,3 -Bis (t-butylperoxyisopropyl) benzene, 1,4-bis (t-butylperoxyisopropyl) benzene, 1,1-di-t-butylperoxy-3,3-trimethylcyclohexane, 4,4-bis- ( t-butyl-peroxy) -n-butylvalerate, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne- 3,1,1-di-tert-butylperoxy-3,5,5-trimethylcyclohexane, p-chlorobenzoyl Hydroperoxide, t- butyl peroxy isopropyl carbonate, t- butyl peroxybenzoate, and the like. These can be used individually by 1 type or in combination of multiple types.

The polyamine-based crosslinking agent is not particularly limited as long as it is a compound having two or more amino groups or a compound having two or more amino groups at the time of crosslinking. A compound in which a plurality of hydrogen atoms of a group hydrocarbon are substituted with an amino group or a hydrazide structure (a structure represented by —CONHNH ₂ , CO represents a carbonyl group) and a compound that is in the form of the compound upon crosslinking are preferred . Specific examples thereof include aliphatic polyamines such as hexamethylene diamine, hexamethylene diamine carbamate, tetramethylene pentamine, hexamethylene diamine cinnamaldehyde adduct, hexamethylene diamine dibenzoate salt; 2,2-bis {4- Aromatic polyamines such as (4-aminophenoxy) phenyl} propane, 4,4′-methylenedianiline, m-phenylenediamine, p-phenylenediamine, 4,4′-methylenebis (o-chloroaniline); And compounds having two or more hydrazide structures such as isophthalic acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide. Of these, hexamethylenediamine carbamate is particularly preferable.

  Here, depending on the type, the reactive silicone oil described above may also act as a crosslinking agent. Therefore, the amount of the crosslinking agent in the nitrile rubber composition of the present invention is the reactive silicone oil used. The amount of the crosslinking agent is preferably 0.1 to 50 parts by weight, more preferably 100 parts by weight with respect to 100 parts by weight of the carboxyl group-containing nitrile rubber. Is 0.5 to 25 parts by weight, more preferably 1 to 10 parts by weight. Moreover, in this invention, when using what has high crosslinking reactivity (for example, what is represented by the said Formula (6)) as reactive silicone oil mentioned above, depending on the compounding quantity, it is not necessarily bridge | crosslinked. It is not necessary to add an agent.

  Moreover, it is preferable that the nitrile rubber composition of the present invention further contains a basic crosslinking accelerator. By further containing a basic crosslinking accelerator, the effect of the present invention becomes more remarkable.

  Specific examples of the basic crosslinking accelerator include 1,8-diazabicyclo [5,4,0] undecene-7 (hereinafter sometimes abbreviated as “DBU”) and 1,5-diazabicyclo [4,3,0]. Nonene-5 (hereinafter sometimes abbreviated as “DBN”), 1-methylimidazole, 1-ethylimidazole, 1-phenylimidazole, 1-benzylimidazole, 1,2-dimethylimidazole, 1-ethyl-2-methylimidazole 1-methoxyethylimidazole, 1-phenyl-2-methylimidazole, 1-benzyl-2-methylimidazole, 1-methyl-2-phenylimidazole, 1-methyl-2-benzylimidazole, 1,4-dimethylimidazole, 1,5-dimethylimidazole, 1,2,4-trimethylimidazole, 1,4-dimethyl-2-ethyl ester Dazole, 1-methyl-2-methoxyimidazole, 1-methyl-2-ethoxyimidazole, 1-methyl-4-methoxyimidazole, 1-methyl-2-methoxyimidazole, 1-ethoxymethyl-2-methylimidazole, 1- Methyl-4-nitroimidazole, 1,2-dimethyl-5-nitroimidazole, 1,2-dimethyl-5-aminoimidazole, 1-methyl-4- (2-aminoethyl) imidazole, 1-methylbenzimidazole, 1 -Methyl-2-benzylbenzimidazole, 1-methyl-5-nitrobenzimidazole, 1-methylimidazoline, 1,2-dimethylimidazoline, 1,2,4-trimethylimidazoline, 1,4-dimethyl-2-ethylimidazoline 1-methyl-phenylimidazoline, 1-methyl-2 -Benzylimidazoline, 1-methyl-2-ethoxyimidazoline, 1-methyl-2-heptylimidazoline, 1-methyl-2-undecylimidazoline, 1-methyl-2-heptadecylimidazoline, 1-methyl-2-ethoxymethyl Basic crosslinking accelerators having a cyclic amidine structure such as imidazoline and 1-ethoxymethyl-2-methylimidazoline; such as tetramethylguanidine, tetraethylguanidine, diphenylguanidine, 1,3-di-ortho-tolylguanidine, orthotolylbiguanide And guanidine-based basic crosslinking accelerators; aldehyde amine-based basic crosslinking accelerators such as n-butyraldehyde aniline and acetaldehyde ammonia; Of these, guanidine-based basic crosslinking accelerators and basic crosslinking accelerators having a cyclic amidine structure are preferred, and 1,3-di-ortho-tolylguanidine, 1,8-diazabicyclo [5,4,0] undecene. -7 and 1,5-diazabicyclo [4,3,0] nonene-5 are more preferred, 1,8-diazabicyclo [5,4,0] undecene-7 and 1,5-diazabicyclo [4,3,0] Nonene-5 is more preferred, and 1,8-diazabicyclo [5,4,0] undecene-7 is particularly preferred. The basic crosslinking accelerator having a cyclic amidine structure may form a salt with an organic carboxylic acid or an alkyl phosphoric acid.

  The amount of the basic crosslinking accelerator in the nitrile rubber composition of the present invention is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 100 parts by weight of the carboxyl group-containing nitrile rubber. -15 parts by weight, more preferably 0.5-10 parts by weight. If the amount of the basic crosslinking accelerator is too small, the crosslinking speed of the nitrile rubber composition may be too slow and the crosslinking density may decrease. On the other hand, if the blending amount is too large, the crosslinking rate of the crosslinkable rubber composition may be too high to cause scorching, or the storage stability may be impaired.

  The nitrile rubber composition of the present invention preferably contains silica as a reinforcing agent from the viewpoint of improving the mechanical strength and compression set resistance of the resulting rubber cross-linked product.

The silica is not particularly limited, it may be any compound containing a (SiO ₂₎ in the composition formula. Specific examples include natural silica such as quartz powder and silica powder; synthetic silica such as silicic anhydride (silica gel, aerosil, etc.), hydrous silicic acid; silicate metal salt; among these, synthetic silica and silicate metal salt And synthetic silica is particularly preferred. The natural silica and the synthetic silica have a composition formula of (SiO ₂ ) or (SiO ₂ · nH ₂ O) (n is a positive integer).

  The synthetic silica is preferably one that is generally used as a so-called white reinforcing material (white carbon) as a reinforcing material for synthetic rubber.

The content of silica in the nitrile rubber composition of the present invention is preferably 5 to 200 parts by weight, more preferably 10 to 100 parts by weight, and still more preferably 20 to 100 parts by weight with respect to 100 parts by weight of the carboxyl group-containing nitrile rubber. 80 parts by weight. If the silica content is too small, the effect of improving the mechanical strength may not be obtained. On the other hand, if the content is too large, the effect of improving compression set resistance may not be obtained.
Silica can be used alone or in combination of two or more.

  In addition to the above-described components, the nitrile rubber composition of the present invention may be blended with other compounding agents usually used in the rubber processing field. Examples of such compounding agents include reinforcing agents other than silica, fillers, antioxidants, light stabilizers, scorch inhibitors, processing aids, lubricants, adhesives, lubricants, flame retardants, acid acceptors, Examples of the antifungal agent, the antistatic agent, the coloring agent, the silane coupling agent, the co-crosslinking agent, the crosslinking aid, the crosslinking retarder, and the foaming agent. As the compounding amount of these compounding agents, an amount corresponding to the compounding purpose can be appropriately adopted.

In addition, you may mix | blend rubbers other than the carboxyl group containing nitrile rubber mentioned above in the range which does not inhibit the effect of this invention in the nitrile rubber composition of this invention.
Examples of such rubber include acrylic rubber, ethylene-acrylic acid copolymer rubber, styrene-butadiene copolymer rubber, polybutadiene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene terpolymer rubber, Examples include epichlorohydrin rubber, urethane rubber, chloroprene rubber, silicone rubber, fluorine rubber, natural rubber, and polyisoprene rubber.
When the rubber other than the carboxyl group-containing nitrile rubber is blended, the blending amount in the nitrile rubber composition is preferably 60 parts by weight or less, more preferably 30 parts by weight or less, with respect to 100 parts by weight of the carboxyl group-containing nitrile rubber. More preferably, it is 10 parts by weight or less.

  In addition to the reactive silicone oil described above, a plasticizer may be added to the nitrile rubber composition of the present invention as long as the effects of the present invention are not impaired. The plasticizer is not particularly limited, and a plasticizer that is usually used in the rubber processing field can be used. However, since the effect of the present invention becomes more remarkable, it is preferable not to add a plasticizer.

  The nitrile rubber composition of the present invention is prepared by mixing the above components, preferably in a non-aqueous system. As a method for suitably preparing the nitrile rubber composition of the present invention, components excluding thermally unstable components such as reactive silicone oil and cross-linking agent are first kneaded in a mixer such as a Banbury mixer, an intermixer, or a kneader. Then, it is transferred to an open roll and the like, and secondary kneading is performed by adding a thermally unstable component such as a reactive silicone oil or a crosslinking agent. The primary kneading is usually performed at a temperature of 10 to 200 ° C., preferably 30 to 180 ° C., for 1 minute to 1 hour, preferably 1 minute to 30 minutes, and the secondary kneading is usually 10 to 100 ° C., Preferably it is performed at a temperature of 20 to 60 ° C. for 1 minute to 1 hour, preferably 1 minute to 30 minutes.

The compound Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the nitrile rubber composition of the present invention is preferably 5 to 200, more preferably 10 to 150, and particularly preferably 20 to 100. In particular, since the nitrile rubber composition of the present invention contains a reactive silicone oil, the compound Mooney viscosity can be in the above range, whereby the nitrile rubber composition of the present invention is excellent in processability. It will be a thing.

Cross-linked rubber The cross-linked rubber of the present invention is obtained by cross-linking the nitrile rubber composition of the present invention described above.
The rubber cross-linked product of the present invention uses the nitrile rubber composition of the present invention, and is molded by a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, a roll, etc., and heated. It can manufacture by performing a crosslinking reaction and fixing a shape as a crosslinked product. In this case, crosslinking may be performed after molding in advance, or crosslinking may be performed simultaneously with molding. The molding temperature is usually 10 to 200 ° C, preferably 25 to 120 ° C. The crosslinking temperature is usually 100 to 200 ° C, preferably 130 to 190 ° C, and the crosslinking time is usually 1 minute to 24 hours, preferably 2 minutes to 12 hours, particularly preferably 3 minutes to 6 hours. .

  Further, depending on the shape and size of the rubber cross-linked product, even if the surface is cross-linked, it may not be sufficiently cross-linked to the inside. Therefore, secondary cross-linking may be performed by heating.

  As a heating method, a general method used for crosslinking of rubber such as press heating, steam heating, oven heating, and hot air heating may be appropriately selected.

  The rubber cross-linked product of the present invention thus obtained is obtained by using the above-described nitrile rubber composition of the present invention, so that it is excellent in normal physical properties and cold resistance and used in contact with oil. Even in this case, changes in physical properties (for example, changes in hardness and cold resistance) are suppressed.

  For this reason, the rubber cross-linked product of the present invention makes use of such characteristics, and O-rings, packings, diaphragms, oil seals, shaft seals, bearing seals, well head seals, pneumatic equipment seals, and air conditioner cooling devices. Seals for fluorocarbons or fluorohydrocarbons or carbon dioxide used for compressors for refrigerators and air conditioners, supercritical carbon dioxide or subcritical carbon dioxide seals used for cleaning media for precision cleaning, rolling Various seal materials such as seals for valves (rolling bearings, automotive hub units, automotive water pumps, linear guide devices, ball screws, etc.), valves and valve seats, BOP (Blow Out Preventar), platters; intake manifolds and cylinders Attach to the connection with the head Intake manifold gasket, cylinder head gasket attached to the connection between the cylinder block and cylinder head, rocker cover gasket attached to the connection between the rocker cover and cylinder head, oil pan and cylinder block or transmission case Various types of gaskets such as an oil pan gasket mounted on the part, a gasket for a fuel cell separator mounted between a pair of housings sandwiching a unit cell having a positive electrode, an electrolyte plate, and a negative electrode, a top cover gasket for a hard disk drive, etc. Various rolls such as rolls, iron rolls, paper rolls, industrial rolls, and office machine rolls; flat belts (film core flat belts, cord flat belts, laminated flat belts, single flat belts, etc.), V belts ( La Pud V-belt, low-edge V-belt, etc.), V-ribbed belt (single V-ribbed belt, double V-ribbed belt, wrapped V-ribbed belt, back rubber V-ribbed belt, upper cog V-ribbed belt, etc.), CVT belt, timing belt, toothed belt, conveyor Various belts such as belts and submersible belts; fuel hose, turbo air hose, oil hose, radiator hose, heater hose, water hose, vacuum brake hose, control hose, air conditioner hose, brake hose, power steering hose, air hose, marine Various hoses such as hoses, risers and flow lines; various boots such as CVJ boots, propeller shaft boots, constant velocity joint boots, rack and pinion boots; cushion materials, dynamic Damping material rubber parts such as dampers, rubber couplings, air springs, anti-vibration materials; dust covers, automotive interior parts, tires, coated cables, shoe soles, electromagnetic wave shields, adhesives for flexible printed circuit boards, fuel cells In addition to separators, it can be used in a wide range of applications such as cosmetics and pharmaceuticals, food contact, and electronics. Among these, the crosslinked product of the present invention can be suitably used as a sealing material, a belt, a hose or a gasket.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples. In the following, “part” is based on weight unless otherwise specified. The test and evaluation were as follows.

Composition of carboxyl group-containing (highly saturated) nitrile rubber The content ratio of each monomer unit constituting the carboxyl group-containing nitrile rubber was measured by the following method.
That is, the content ratio of mono n-butyl maleate units was 0.2 g of carboxyl group-containing nitrile rubber of 0.2 mm square, 100 ml of 2-butanone was added and stirred for 16 hours, and then 20 ml of ethanol and 10 ml of water were added and stirred. Then, using a 0.02N aqueous ethanol solution of potassium hydroxide, titration with thymolphthalein as an indicator at room temperature was performed to determine the number of moles of carboxyl groups relative to 100 g of carboxyl group-containing nitrile rubber. It calculated by converting into the quantity of n-butyl unit.
The content ratio of the 1,3-butadiene unit and the saturated butadiene unit was calculated by measuring the iodine value (according to JIS K 6235) before and after the hydrogenation reaction using carboxyl group-containing nitrile rubber. .
The content ratio of the acrylonitrile unit was calculated by measuring the nitrogen content in the carboxyl group-containing nitrile rubber by the Kjeldahl method according to JIS K6383.

Iodine value The iodine value of the carboxyl group-containing (highly saturated) nitrile rubber was measured according to JIS K 6235.

Mooney viscosity (Polymer Mooney, Compound Mooney)
The Mooney viscosity (polymer Mooney, compound Mooney) of the carboxyl group-containing (highly saturated) nitrile rubber and the nitrile rubber composition was measured according to JIS K6300-1 (unit: [ML _{1 + 4} , 100 ° C.]).

Normal physical properties (tensile strength, elongation, hardness)
The nitrile rubber composition was put into a mold having a length of 15 cm, a width of 15 cm, and a depth of 0.2 cm, and press-molded at 170 ° C. for 20 minutes while being pressed at a press pressure of 10 MPa to obtain a sheet-like crosslinked product. Subsequently, the obtained cross-linked product was transferred to a gear type oven and subjected to secondary cross-linking at 170 ° C. for 4 hours, and the obtained sheet-like rubber cross-linked product was punched with a No. 3 dumbbell to prepare a test piece. And using this obtained test piece, according to JIS K6251, the tensile strength and elongation of a rubber cross-linked product are used, and according to JIS K6253, the hardness of a rubber cross-linked product is measured using a durometer hardness tester (type A). Each was measured.

Cold resistance test (TR test)
After obtaining a sheet-like rubber cross-linked product in the same manner as the evaluation of the normal physical properties, cold resistance was measured by TR test (low temperature elastic recovery test) according to JIS K6261. TR10 (unit: ° C.) is an index of cold resistance, and it can be determined that the lower this value, the better the cold resistance.

Oil resistance immersion test (IRM901, IRM903)
In the same manner as in the evaluation of normal physical properties, after obtaining a sheet-like rubber cross-linked product, it was immersed in test oils (IRM901 and IRM903) adjusted to 150 ° C. according to JIS K6258 for 72 hours. An oil resistance immersion test was conducted.
In the oil-resistant immersion test, each of the volume swelling degree ΔV after oil immersion, the hardness after oil immersion, the change in hardness before and after oil immersion, TR10 after oil immersion, and the change in TR10 before and after oil immersion ΔTR10 Evaluation was performed. In the following, the rubber cross-linked product after oil immersion was vacuum-dried at 100 ° C. for 48 hours and sufficiently cooled in an atmosphere at a temperature of 23 ° C. and a humidity of 50%.
The volume swelling degree ΔV (unit:%) after oil immersion was measured by measuring the volume of the rubber cross-linked product before and after oil immersion, and “ΔV = ([volume after oil immersion−volume before oil immersion] / oil immersion”. Calculated according to the previous volume) × 100 ”.
The hardness after oil immersion was measured by the method described above for the hardness of the rubber cross-linked product after oil immersion. The hardness change before and after oil immersion was calculated from the hardness of the crosslinked rubber before and after oil immersion according to “Hardness change = hardness after oil immersion−hardness before oil immersion”.
TR10 after oil immersion measured TR10 of the rubber cross-linked product after oil immersion by the method described above. Further, the change ΔTR10 of TR10 before and after oil immersion was calculated according to “ΔTR10 = TR10 after oil immersion−TR10 before oil immersion” from TR10 of the rubber crosslinked product before and after oil immersion.

Using a mold having a compression set of 30 mm inner diameter and a ring diameter of 3 mm, the nitrile rubber composition was crosslinked at 170 ° C. for 20 minutes at a press pressure of 10 MPa, and then subjected to secondary crosslinking at 170 ° C. for 4 hours. -A ring-shaped test piece was obtained. Then, using the obtained O-ring-shaped test piece, the distance between two planes sandwiching the O-ring-shaped test piece is held at 150 ° C. for 168 hours in a state compressed by 25% in the ring thickness direction. The O-ring compression set was measured in accordance with JIS K6262. The smaller this value, the better the compression set resistance.

Surface Friction Resistance Test In the same manner as the above-described evaluation of normal physical properties, a sheet-like press-crosslinked product was obtained, and the obtained sheet-like press-crosslinked product was subjected to Haydon type surface property measuring machine (trade name “HEIDON-14D”). , Manufactured by Shinto Kagaku Co., Ltd.). In the measurement, a ball indenter (SUSφ10) was used as a measurement jig, and the sheet-like press cross-linked product was moved horizontally under the conditions of a test load of 100 g (vertical load N) and a test speed of 50 mm / min. The frictional force F (unit: gf) applied to the dynamic strain amplifier of the Haydon type surface property measuring machine was measured, and the friction coefficient μ was calculated based on the following formula.
μ = F / N
In this test, the value of the friction coefficient μ is continuously recorded from the state where the sheet-like press-crosslinked product is stationary until it becomes constant at the test speed. The value when the friction coefficient μ is in a constant state is defined as “dynamic friction coefficient”.
It can be determined that the smaller the values of “static friction coefficient” and “dynamic friction coefficient”, the lower the surface friction resistance and the better the sliding characteristics.

Synthesis example 1
In a reactor, 180 parts of ion-exchanged water, 25 parts of a 10% strength by weight aqueous sodium dodecylbenzenesulfonate solution, 37.0 parts of acrylonitrile, 4 parts of mono-n-butyl maleate, and t-dodecyl mercaptan (molecular weight modifier) 0 .5 parts in order, and after replacing the internal gas with nitrogen three times, 57 parts of 1,3-butadiene was charged. Maintaining the reactor at 5 ° C., charging 0.1 part of cumene hydroperoxide (polymerization initiator), continuing the polymerization reaction while stirring, and when the polymerization conversion rate reached 40% and 60% during the process, 1 part each of mono n-butyl maleate was added and the polymerization reaction was continued for 16 hours. Next, 0.1 part of a 10% by weight hydroquinone aqueous solution (polymerization terminator) was added to terminate the polymerization reaction, and then the residual monomer was removed using a rotary evaporator with a water temperature of 60 ° C. to obtain a carboxyl group-containing nitrile rubber. Latex (L1) (solid content concentration of about 30% by weight) was obtained.

Next, after adding 2 volumes of methanol to the obtained latex (L1) and coagulating it, the solid substance (crumb) was taken out by filtration and vacuum-dried at 60 ° C. for 12 hours to obtain a carboxyl group-containing nitrile. A rubber (R1) was obtained. The polymer Mooney viscosity [ML _{1 + 4} , 100 ° C.] of the carboxyl group-containing nitrile rubber (R1) was 12. The content ratio of each monomer unit constituting the obtained carboxyl group-containing nitrile rubber (R1) was 36.7% by weight of acrylonitrile unit, 5.7% by weight of mono n-butyl maleate unit, 1, 3 -It was 57.6 weight% of butadiene units.

  Next, in the autoclave, latex (L1) and a palladium catalyst (1 wt% palladium acetate) were added so that the palladium content relative to the dry weight of the rubber contained in the latex (L1) obtained above was 1,000 ppm. A solution obtained by mixing an acetone solution and an equal weight of ion exchange water) was added, and a hydrogenation reaction was performed at a hydrogen pressure of 3 MPa and a temperature of 50 ° C. for 6 hours to obtain a carboxyl group-containing highly saturated nitrile rubber latex (L2). .

The obtained latex (L2) was coagulated by adding 2 volumes of methanol, and then filtered to take out a solid (crumb), which was vacuum-dried at 60 ° C. for 12 hours to obtain a carboxyl group-containing polymer. A saturated nitrile rubber (R2) was obtained. The iodine value of the carboxyl group-containing highly saturated nitrile rubber (R2) was 6.5, and the polymer Mooney viscosity [ML _{1 + 4} , 100 ° C.] was 40. The content ratio of each monomer unit constituting the carboxyl group-containing highly saturated nitrile rubber (R2) is 35.7% by weight of acrylonitrile unit, 5.7% by weight of mono n-butyl maleate unit, 1,3-butadiene unit It was 58.6% by weight (including the hydrogenated part).

Example 1
Using a Banbury mixer, 100 parts of the carboxyl group-containing highly saturated nitrile rubber (R2) obtained in Synthesis Example 1, 200 parts of MT carbon (trade name “Thermax MT”, manufactured by Cancarb, carbon black), side chain type Amino-modified silicone oil (trade name “KF-868”, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 90 mm ² / s, functional group equivalent: 8800 g / mol, in the above formula (1), X ¹ = NH ₂ 49.5 parts, 1 part of polyoxyethylene stearyl ether phosphoric acid (trade name “phosphanol RL-210”, manufactured by Toho Chemical Co., Ltd., processing aid), and 4,4′-di- ( α, α-dimethylbenzyl) diphenylamine (trade name “Naugard 445”, manufactured by Crompton, anti-aging agent) 1.5 parts was added. Kneading, and then transferring the mixture to a roll, 2 parts of 1,3-di-o-tolylguanidine (trade name “Noxeller DT”, manufactured by Ouchi Shinsei Chemical Co., Ltd., basic crosslinking accelerator), and hexa A nitrile rubber composition was prepared by adding 2.2 parts of methylenediamine carbamate (trade name “Diak # 1”, manufactured by DuPont Dow Elastomer Co., Ltd., polyamine-based crosslinking agent belonging to aliphatic polyamines) and kneading. did.

  And each evaluation and test of compound Mooney viscosity, a normal state physical property, a cold resistance test, and an oil-resistant immersion test was done by the method mentioned above. The results are shown in Table 1.

Example 2
In Example 1, instead of 49.5 parts of the side chain type amino-modified silicone oil, both-end type amino-modified silicone oil (trade name “X-22-161B”, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 55 mm ² / s, functional group equivalent: 1500 g / mol, 49.5 parts of the compound represented by the above formula (6)), and the same manner as in Example 1 except that hexamethylenediamine carbamate was not used. A nitrile rubber composition was prepared and evaluated in the same manner. The results are shown in Table 1.

Example 3
In Example 2, instead of 2 parts of 1,3-di-o-tolylguanidine, 1,8-diazabicyclo [5,4,0] -undecene-7 (DBU) (trade name: “RHENOGRAN XLA-60 ( GE2014) ", 4 parts by Rhein Chemie, DBU 60% (including a part that is a zinc dialkyl diphosphate salt), and 4 parts of an acrylic acid polymer and a dispersing agent 40%, a basic crosslinking accelerator) Except for the above, a nitrile rubber composition was prepared in the same manner as in Example 2 and evaluated in the same manner. The results are shown in Table 1.

Example 4
In Example 2, a nitrile rubber composition was prepared in the same manner as in Example 2 except that 100 parts of carboxyl group-containing nitrile rubber (R1) was used instead of 100 parts of carboxyl group-containing highly saturated nitrile rubber (R2). The same evaluation was made. The results are shown in Table 1.

Example 5
In Example 1, in place of 49.5 parts of the side chain amino-modified silicone oil, a double-ended epoxy-modified silicone oil (trade name “X-22-163B”, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 60 mm ² / s, functional group equivalent: 1750 g / mol, in the formula ^{(2), X 2, X} 3 = compound is an epoxy ethyl) with 49.5 parts of 2.2 the amount of hexamethylenediamine carbamate A nitrile rubber composition was prepared in the same manner as in Example 1 except that the amount was changed from 0.4 part to 0.4 part, and evaluated in the same manner. The results are shown in Table 1.

Example 6
In Example 1, instead of 49.5 parts of the side-chain amino-modified silicone oil, both-end mercapto-modified silicone oil (trade name “X-22-167B”, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 55 mm ² / s, functional group equivalent: 1670 g / mol, 49.5 parts of the compound (X ² , X ³ = —SH in the above formula (2)), and the amount of hexamethylenediamine carbamate used was 2.2. A nitrile rubber composition was prepared in the same manner as in Example 1 except that the amount was changed from 0.3 part to 0.3 part, and evaluated in the same manner. The results are shown in Table 1.

Example 7
In Example 1, instead of 49.5 parts of the side chain type amino-modified silicone oil, both-end type carboxyl-modified silicone oil (trade name “X-22-162C”, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 220 mm ² / s, functional group equivalent: 2300 g / mol, 49.5 parts of a compound in which X ² , X ³ = —C (═O) OH in the above formula (2)) was used, and hexamethylenediamine carbamate A nitrile rubber composition was prepared and evaluated in the same manner as in Example 1 except that the amount used was changed from 2.2 parts to 5.2 parts. The results are shown in Table 1.

Example 8
In Example 2, instead of 49.5 parts of both-end type amino-modified silicone oil, one-end type epoxy-modified silicone oil (trade name “X-22-173DX”, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 65 mm ² / s, functional group equivalent: 4500 g / mol, in the above formula (4), 49.5 parts of a compound in which X ⁷ = epoxyethyl) is used, and 1,3-di-o-tolylguanidine is used. Example 1 except that 8 parts of 1,3-bis (t-butylperoxyisopropyl) benzene (organic peroxide) 40% product (manufactured by GEO Specialty Chemicals Inc., Valcup 40KE) was used as a crosslinking agent. A nitrile rubber composition was prepared in the same manner as in Example 2 and evaluated in the same manner. The results are shown in Table 1.

Example 9
In Example 8, instead of 49.5 parts of one-end type epoxy-modified silicone oil, side-chain type amino-modified silicone oil (trade name “KF-868”, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25 ° C .: 90 mm ² / S, functional group equivalent: 8800 g / mol, a nitrile rubber composition was prepared in the same manner as in Example 8 except that 49.5 parts of the compound (X ¹ = NH ₂ in the above formula (1)) was used. The same evaluation was made. The results are shown in Table 1.

Comparative Example 1
A nitrile was prepared in the same manner as in Example 1 except that the side chain amino-modified silicone oil was not used and the amount of hexamethylenediamine carbamate used was changed from 2.2 parts to 2.6 parts. A rubber composition was prepared and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 2
In Example 1, instead of 49.5 parts of the side chain type amino-modified silicone oil, 49.5 parts of trimellitic acid tri-2-ethylhexyl (trade name “ADK Cizer C-8”, manufactured by ADEKA, plasticizer) A nitrile rubber composition was prepared and evaluated in the same manner as in Example 1 except that the amount of hexamethylenediamine carbamate used was changed from 2.2 parts to 2.6 parts. The results are shown in Table 1.

  From Table 1, when reactive silicone oil is blended with carboxyl group-containing nitrile rubber (R1) or carboxyl group-containing highly saturated nitrile rubber (R2), compound Mooney viscosity is low, processability is excellent, and excellent normal physical properties. Further, the volume change, the hardness change, and the change in TR10 which is an index of cold resistance are all small and excellent in oil resistance (Examples 1 to 9).

  On the other hand, when no reactive silicone oil was blended, the compound Mooney viscosity was high and the processability was poor (Comparative Example 1). In addition, when tri-2-ethylhexyl trimellitic acid is used as a plasticizer instead of reactive silicone oil, the change in volume, hardness change, and change in TR10, which is an index of cold resistance, caused by oil immersion is The result was inferior in oil resistance (Comparative Example 2).

Example 10
Using a Banbury mixer, 100 parts of the carboxyl group-containing highly saturated nitrile rubber (R2) obtained in Synthesis Example 1, 50 parts of silica (trade name “Nipsil ER”, manufactured by Tosoh Silica Co., Ltd.), trimellitic acid tri- 2-ethylhexyl (trade name “Adekasizer C-8”, manufactured by ADEKA, plasticizer) 5 parts, 4,4′-di- (α, α-dimethylbenzyl) diphenylamine (trade name “NOCRACK CD”, Ouchi Shinsei Chemical Co., Ltd., anti-aging agent) 1.5 parts, stearic acid 1 part, polyoxyethylene stearyl ether phosphoric acid (trade name “phosphanol RL-210”, manufactured by Toho Chemical Co., Ltd., processing aid) 1 part, 1 part of 3-aminopropyltriethoxysilane (trade name “Z-6011”, manufactured by Toray Dow Corning Co., Ltd., silane coupling agent), and side chain type amino-modified silicone Yl (trade name "KF-868", manufactured by Shin-Etsu Chemical Co., Ltd., dynamic viscosity at 25 ℃: 90mm ² / s, functional group equivalent: 8800 g / mol, in the above formula ^(1), the compound is X 1 = NH ₂ ) 5 parts was added and mixed at 50 ° C. for 5 minutes. Subsequently, the obtained mixture was transferred to a roll at 50 ° C., and hexamethylenediamine carbamate (trade name “Diak # 1”, manufactured by DuPont Dow Elastomer Co., Ltd., polyamine crosslinking agent belonging to aliphatic polyamines) 2.55 parts , And 1,8-diazabicyclo [5,4,0] -undecene-7 (DBU) (trade name “RHENOGRAN XLA-60 (GE2014)”, manufactured by RheinChemie, DBU 60% (becomes zinc dialkyldiphosphate salt) 4 parts of a basic crosslinking accelerator) was added and kneaded to prepare a nitrile rubber composition.

  Then, by using the obtained nitrile rubber composition, the compound Mooney viscosity, normal state properties, oil immersion resistance test (IRM901, volume swelling degree ΔV after oil immersion), compression set test, cold resistance test are performed by the above-described methods. Each evaluation of the surface friction resistance test was performed. The results are shown in Table 2.

Example 11
In Example 10, the amount of side chain amino-modified silicone oil used was changed from 5 parts to 10 parts, and the amount of hexamethylenediamine carbamate used was changed from 2.55 parts to 2.51 parts. A nitrile rubber composition was prepared in the same manner as in No. 10, and evaluated in the same manner. The results are shown in Table 2.

Example 12
In Example 10, the amount of side chain amino-modified silicone oil used was changed from 5 parts to 15 parts, and the amount of hexamethylenediamine carbamate used was changed from 2.55 parts to 2.46 parts. A nitrile rubber composition was prepared in the same manner as in No. 10, and evaluated in the same manner. The results are shown in Table 2.

Example 13
In Example 10, the amount of side chain amino-modified silicone oil used was changed from 5 parts to 10 parts, the amount of 3-aminopropyltriethoxysilane used was changed from 1 part to 0 parts, and hexamethylenediamine carbamate was further added. A nitrile rubber composition was prepared in the same manner as in Example 10 except that the amount of was changed from 2.55 parts to 2.51 parts, and evaluated in the same manner. The results are shown in Table 2.

Example 14
In Example 10, the amount of side chain amino-modified silicone oil used was changed from 5 parts to 10 parts, the amount of hexamethylenediamine carbamate used was changed from 2.55 parts to 2.51 parts, and stearyl alcohol ( A nitrile rubber composition was prepared and evaluated in the same manner as in Example 10 except that 5 parts of Wako Pure Chemical Industries, Ltd. (saturated alcohol having 18 carbon atoms) was added. The results are shown in Table 2.

  From Table 2, the rubber cross-linked product obtained by cross-linking the carboxyl group-containing highly saturated nitrile rubber and the nitrile rubber composition containing reactive silicone oil and silica has excellent normal properties and oil resistance, and is also resistant to compression. The results were excellent in permanent distortion and surface friction resistance (Examples 10 to 14). In Examples 10 to 14, when the cold resistance test (TR test) was performed in accordance with the above-described method, all were the same as in Examples 1 to 9 and were excellent in cold resistance.

Claims (8)

A nitrile rubber composition containing a carboxyl group-containing nitrile rubber and a reactive silicone oil , wherein the carboxyl group-containing nitrile rubber is an α, β-ethylenically unsaturated dicarboxylic acid with respect to all monomer units. A nitrile rubber composition containing a monoester monomer unit in a proportion of 0.1 to 20% by weight .   The nitrile rubber composition according to claim 1, wherein the carboxyl group-containing nitrile rubber has an iodine value of 120 or less. The carboxyl group-containing nitrile rubber is 5 to 60% by weight of α, β-ethylenically unsaturated nitrile monomer unit, and 0.1 to 20% by weight of α, β-ethylenically unsaturated dicarboxylic acid monoester monomer unit. The nitrile rubber composition according to claim 1 or 2, comprising 15 to 94.9% by weight of a conjugated diene monomer unit.   The reactive silicone oil has at least one reactive group selected from the group consisting of a hydroxyl group, an amino group, a mercapto group, an epoxy group, a carboxyl group, an acrylic group, and a methacryl group. The nitrile rubber composition described in 1.   The nitrile rubber composition according to any one of claims 1 to 4, further comprising silica. The nitrile rubber composition according to any one of claims 1 to 5, further comprising a polyamine-based crosslinking agent. Rubber cross-linked product obtained by crosslinking a nitrile rubber composition according to any one of claims 1-6. The rubber cross-linked product according to claim 7 , which is a sealing material, a belt, a hose or a gasket.