阅读说明：本技术 丙烯酸类橡胶组合物、交联橡胶层叠体和燃料管 (Acrylic rubber composition, crosslinked rubber laminate, and fuel pipe ) 是由 成田智幸 茂崎紫穗 于 2019-01-31 设计创作，主要内容包括：本发明提供一种丙烯酸类橡胶组合物,其包含多元胺化合物、含羧基的丙烯酸类橡胶、以及含杂原子醇。(The present invention provides an acrylic rubber composition comprising a polyamine compound, a carboxyl group-containing acrylic rubber, and a heteroatom-containing alcohol.)

1. An acrylic rubber composition comprising a polyamine compound, a carboxyl group-containing acrylic rubber, and a heteroatom-containing alcohol.

2. The acrylic rubber composition according to claim 1, wherein the heteroatom-containing alcohol is an amino alcohol.

3. The acrylic rubber composition according to claim 1 or 2, wherein the mass ratio of the heteroatom alcohol to the carboxyl group-containing acrylic rubber is 1 to 5%.

4. A crosslinked rubber laminate obtained by crosslinking and bonding the acrylic rubber composition according to any one of claims 1 to 3 and a fluororubber composition.

5. The crosslinked rubber laminate according to claim 4, wherein the fluororubber composition contains an organic peroxide-based crosslinking agent.

6. The crosslinked rubber laminate according to claim 4 or 5, wherein the fluororubber composition contains a fluororubber containing 69 mass% or more of fluorine atoms.

7. A fuel pipe having the crosslinked rubber laminate as claimed in any one of claims 4 to 6.

Technical Field

The present invention relates to an acrylic rubber composition, a crosslinked rubber laminate, and a fuel pipe.

Background

Conventionally, as a material for fuel pipes, a crosslinked rubber laminate obtained by crosslinking and bonding an acrylic rubber composition and a fluororubber composition has been known.

Such an acrylic rubber composition contains a polyamine compound and a carboxyl group-containing acrylic rubber, but an additive is added to impart cross-linking adhesiveness to the fluororubber composition (see, for example, patent document 1).

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional acrylic rubber composition, it is desired to further improve the crosslinking adhesiveness to the fluororubber composition.

An object of one embodiment of the present invention is to provide an acrylic rubber composition having excellent crosslinking adhesiveness to a fluororubber composition.

Means for solving the problems

An acrylic rubber composition according to one embodiment of the present invention includes a polyamine compound, a carboxyl group-containing acrylic rubber, and a heteroatom-containing alcohol.

The heteroatom-containing alcohol is preferably an aminoalcohol.

The mass ratio of the heteroatom alcohol to the carboxyl group-containing acrylic rubber is preferably 1 to 5%.

In a crosslinked rubber laminate according to another embodiment of the present invention, the acrylic rubber composition and the fluororubber composition are crosslinked and bonded.

The fluororubber composition preferably contains an organic peroxide crosslinking agent.

The fluororubber composition preferably contains a fluororubber having a fluorine atom content of 69 mass% or more.

A fuel pipe according to another embodiment of the present invention has the crosslinked rubber laminate.

Effects of the invention

According to one embodiment of the present invention, an acrylic rubber composition having excellent crosslinking adhesiveness to a fluororubber composition can be provided.

Detailed Description

The following describes embodiments of the present invention.

< acrylic rubber composition >

The acrylic rubber composition of the present embodiment includes a polyamine compound, a carboxyl group-containing acrylic rubber, and a heteroatom-containing alcohol.

The acrylic rubber composition of the present embodiment can be used to produce a crosslinked rubber laminate by crosslinking and bonding with a fluororubber composition, as described later.

< acrylic rubber containing carboxyl group >

The carboxyl group-containing acrylic rubber has a structural unit derived from a (meth) acrylate ester and has a carboxyl group.

In the present specification, (meth) acrylate means acrylate or methacrylate.

Further, (meth) acrylate refers to a monofunctional monomer having 1 acryloyloxy group or methacryloyloxy group.

Further, the carboxyl group of the carboxyl group-containing acrylic rubber reacts with the amino group of the polyamine compound to crosslink the acrylic rubber composition, thereby forming an acrylic rubber crosslinked product. This improves the heat resistance of the acrylic rubber crosslinked product.

Examples of the method for synthesizing the carboxyl group-containing acrylic rubber include the following methods: (a) a method of copolymerizing a (meth) acrylate with an α, β -ethylenically unsaturated carboxylic acid; (b) a method of subjecting a carbon-carbon unsaturated bond-containing compound having a carboxyl group to an addition reaction with an acrylic rubber having no carboxyl group in the presence of a radical polymerization initiator; (c) and a method of hydrolyzing a part of a group derived from a carboxyl group such as a carboxylate group or a carboxylate amide group in the acrylic rubber having no carboxyl group. Among these, the synthesis method of the above (a) is preferable.

[ meth (acrylic acid ester ]

The (meth) acrylic acid ester is not particularly limited, and examples thereof include alkyl (meth) acrylates, alkoxyalkyl (meth) acrylates, and the like.

The alkyl (meth) acrylate is not particularly limited, and is preferably an ester of an alkanol having 1 to 8 carbon atoms and (meth) acrylic acid.

Specific examples of the ester of an alkanol having 1 to 8 carbon atoms and (meth) acrylic acid include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and cyclohexyl (meth) acrylate. Among these, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferable, and ethyl acrylate and n-butyl acrylate are particularly preferable.

The alkoxyalkyl (meth) acrylate is not particularly limited, and is preferably an ester of an alkoxyalkyl alcohol having 2 to 8 carbon atoms and (meth) acrylic acid.

Specific examples of the ester of an alkoxyalkyl alcohol having 2 to 8 carbon atoms and (meth) acrylic acid include methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, and 4-methoxybutyl (meth) acrylate. Among these, 2-ethoxyethyl (meth) acrylate and 2-methoxyethyl (meth) acrylate are preferable, and 2-ethoxyethyl acrylate and 2-methoxyethyl acrylate are particularly preferable.

The (meth) acrylic acid esters may be used alone or in combination of two or more.

The proportion of the structural unit derived from the (meth) acrylate to the total structural units of the carboxyl group-containing acrylic rubber is preferably 50 to 99.9% by mass, more preferably 60 to 99.5% by mass, and still more preferably 70 to 99.5% by mass. When the proportion of the structural unit derived from the (meth) acrylate to the entire structural unit of the carboxyl group-containing acrylic rubber is 50% by mass or more, the weather resistance of the acrylic rubber crosslinked product is improved, and when it is 99.9% by mass or less, the compression set resistance of the acrylic rubber crosslinked product is improved.

The carboxyl group-containing acrylic rubber preferably has a proportion of a structural unit derived from an alkyl (meth) acrylate to a structural unit derived from a (meth) acrylate of 30 to 100 mass%, and a proportion of a structural unit derived from an alkoxyalkyl (meth) acrylate to a structural unit derived from a (meth) acrylate of 70 to 0 mass%.

< alpha, beta-ethylenically unsaturated carboxylic acid >

The α, β -ethylenically unsaturated carboxylic acid is not particularly limited as long as it is a crosslinkable monofunctional monomer copolymerizable with (meth) acrylic acid ester, and examples thereof include an α, β -ethylenically unsaturated monocarboxylic acid having 3 to 12 carbon atoms, an α, β -ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, and a monoester of an α, β -ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and an alkanol having 1 to 8 carbon atoms.

Specific examples of the α, β -ethylenically unsaturated monocarboxylic acid having 3 to 12 carbon atoms include acrylic acid, methacrylic acid, α -ethylacrylic acid, crotonic acid, cinnamic acid, and the like.

Specific examples of the α, β -ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms include butenedioic acids such as fumaric acid and maleic acid; itaconic acid; citric acid; chloromaleic acid, and the like.

The alpha, beta-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms may be an acid anhydride.

Specific examples of the monoester of an α, β -ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and an alkanol having 1 to 8 carbon atoms include monomethyl fumarate, monoethyl fumarate, mono-n-propyl fumarate, monoisopropyl fumarate, mono-n-butyl fumarate, monoisobutyl fumarate, monomethyl maleate, monoethyl maleate, mono-n-propyl maleate, monoisopropyl maleate, mono-n-butyl maleate, and monoisobutyl maleate; butenedioic acid monoesters having an alicyclic structure such as monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexene fumarate, monocyclopentyl maleate, monocyclohexyl maleate, and monocyclohexene maleate; itaconic monoesters such as monomethyl itaconate, monoethyl itaconate, mono-n-butyl itaconate and monocyclohexyl itaconate.

Among these, monoesters of α, β -ethylenically unsaturated dicarboxylic acids having 4 to 12 carbon atoms and alkanols having 1 to 8 carbon atoms are preferable from the viewpoint of crosslinking adhesiveness to the fluororubber composition, and secondary alkyl esters of α, β -ethylenically unsaturated dicarboxylic acids having 4 carbon atoms such as monoisopropyl fumarate, monoisobutyl fumarate, monocyclopentyl fumarate, monocyclohexyl fumarate, monoisopropyl maleate, monoisobutyl maleate, monocyclopentyl maleate, and monocyclohexyl maleate are particularly preferable.

The α, β -ethylenically unsaturated carboxylic acid may be used alone or in combination of two or more.

The proportion of the structural unit derived from the α, β -ethylenically unsaturated carboxylic acid to the total structural units of the carboxyl group-containing acrylic rubber is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and still more preferably 0.5 to 5% by mass. When the proportion of the structural unit derived from an α, β -ethylenically unsaturated carboxylic acid to the entire structural unit of the carboxyl group-containing acrylic rubber is 0.1% by mass or more, the mechanical properties and heat resistance of the acrylic rubber crosslinked product are improved, and when it is 10% by mass or less, the elongation at break and the compression set resistance of the acrylic rubber crosslinked product are improved.

The content of carboxyl groups in the carboxyl group-containing acrylic rubber (the number of moles of carboxyl groups per 100g of the carboxyl group-containing rubber [ ephr ]]) Preferably 4 × 10^-4～4×10^-1ephr, more preferably 1 × 10^-3～2×10^-1ephr, more preferably 5 × 10^-3～1×10^-1When the content of carboxyl groups in the carboxyl group-containing acrylic rubber is 4 × 10^-4When the time is longer than ephr, the mechanical properties and heat resistance of the crosslinked acrylic rubber are improved, and when 4 × 10^-1When the time is not more than ephr, the elongation at break and compression set resistance of the acrylic rubber crosslinked product are improved.

In addition, the carboxyl group-containing acrylic rubber preferably has a secondary alkyl ester structure from the viewpoint of processability and scorch stability of the acrylic rubber composition.

< other crosslinkable monofunctional monomer >

The carboxyl group-containing acrylic rubber may further have a structural unit derived from a crosslinkable monofunctional monomer other than the α, β -ethylenically unsaturated carboxylic acid (hereinafter referred to as other crosslinkable monofunctional monomer) as necessary.

The other crosslinkable monofunctional monomer is not particularly limited as long as it is a crosslinkable monofunctional monomer copolymerizable with (meth) acrylate and α, β -ethylenically unsaturated carboxylic acid, and examples thereof include a monomer having a halogen atom, a monomer having an epoxy group, and a monomer having a hydroxyl group.

The other crosslinkable monofunctional monomers may be used alone or in combination of two or more.

The ratio of the structural unit derived from the other crosslinkable monofunctional monomer to the whole structural unit of the carboxyl group-containing acrylic rubber is not particularly limited and can be determined appropriately.

< other monofunctional monomer >

The carboxyl group-containing acrylic rubber may further have a structural unit derived from a monofunctional monomer (hereinafter referred to as other monofunctional monomer) other than the above-mentioned (meth) acrylate and crosslinkable monofunctional monomer, as required.

The other monofunctional monomer is not particularly limited as long as it can be copolymerized with a (meth) acrylate or an α, β -ethylenically unsaturated carboxylic acid, and examples thereof include aromatic vinyl compounds, α, β -ethylenically unsaturated nitrile compounds, olefin compounds, vinyl ester compounds, vinyl ether compounds, and the like.

Specific examples of the aromatic vinyl compound include styrene and α -methylstyrene.

Specific examples of the α, β -ethylenically unsaturated nitrile compound include acrylonitrile and methacrylonitrile.

Specific examples of the olefin-based compound include ethylene, propylene, 1-butene, 1-octene, and the like.

Specific examples of the vinyl ester compound include vinyl acetate and the like.

Specific examples of the vinyl ether compound include ethyl vinyl ether and n-butyl vinyl ether.

Among these, styrene, acrylonitrile, methacrylonitrile, ethylene and vinyl acetate are preferable, and acrylonitrile, methacrylonitrile and ethylene are more preferable.

Further, other monofunctional monomers may be used alone, or two or more thereof may be used in combination.

The proportion of the structural unit derived from another monofunctional monomer to the entire structural unit of the carboxyl group-containing acrylic rubber is preferably 49.9% by mass or less, more preferably 39.5% by mass or less, and still more preferably 29.5% by mass or less.

< polyfunctional monomer >

The carboxyl group-containing acrylic rubber may further have a structural unit derived from a polyfunctional monomer in addition to the structural unit derived from a monofunctional monomer.

Here, the polyfunctional monomer is a compound having 2 or more groups copolymerizable with (meth) acrylate and α, β -ethylenically unsaturated carboxylic acid.

The polyfunctional monomer is not particularly limited as long as it can be copolymerized with a (meth) acrylate or an α, β -ethylenically unsaturated carboxylic acid, and examples thereof include divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, dipropylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. Among these, divinylbenzene, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate are preferable.

The polyfunctional monomer may be used alone or in combination of two or more.

The proportion of the structural unit derived from the polyfunctional monomer to the entire structural unit of the carboxyl group-containing acrylic rubber is preferably 10.0% by mass or less, more preferably 7.5% by mass or less, and still more preferably 5.0% by mass or less.

< method for synthesizing carboxyl group-containing acrylic rubber >

As a method for synthesizing the carboxyl group-containing acrylic rubber, a known synthesis method such as emulsion polymerization, suspension polymerization, bulk polymerization, or solution polymerization can be used. Among these, the emulsion polymerization method is preferred because it enables polymerization under normal pressure.

The emulsion polymerization method may be any of a batch method, a semi-batch method, and a continuous method.

The carboxyl group-containing acrylic rubber is obtained as a solid material after the monomer emulsion is polymerized, and then subjected to a coagulation step and a drying step.

< characteristics of carboxyl group-containing acrylic rubber >

The Mooney viscosity ML1+4(100 ℃) of the carboxyl group-containing acrylic rubber is preferably 10 to 80, more preferably 20 to 70, and still more preferably 25 to 60.

< polyamine Compound >

The polyamine compound functions as a crosslinking agent.

The polyamine compound is a compound having 2 or more amino groups or a compound which can be converted into a compound having 2 or more amino groups at the time of crosslinking, but does not include a compound in which an amino group such as guanidine is bonded to a carbon atom other than a carbon atom of a non-conjugated nitrogen-carbon double bond (except a compound in which 2 or more amino groups are bonded to a carbon atom other than a carbon atom of a non-conjugated nitrogen-carbon double bond).

The polyamine compound is not particularly limited as long as it can crosslink the carboxyl group-containing acrylic rubber, and examples thereof include aliphatic polyamine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, and N, N-bisphenylenepropylene-1, 6-hexamethylenediamine, and carbonates thereof; aromatic polyamine compounds such as 4,4 '-methylenedianiline, p-phenylenediamine, m-phenylenediamine, 4' -diaminodiphenyl ether, 3,4 '-diaminodiphenyl ether, 4' - (m-phenylenediisopropylidene) diphenylamine, 4'- (p-phenylenediisopropylidene) diphenylamine, 2' -bis [4- (4-aminophenoxy) phenyl ] propane, 4 '-diaminobenzanilide, 4' -bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, and 1,3, 5-benzenetriamine. Among these, from the viewpoint of crosslinking adhesiveness to the fluororubber composition, the aliphatic polyamine compound or the carbonate thereof is preferable, and hexamethylenediamine carbamate is more preferable.

The polyamine compound may be used alone, or two or more of them may be used in combination.

In the acrylic rubber composition of the present embodiment, the mass ratio of the polyamine compound to the carboxyl group-containing acrylic rubber is preferably 0.05 to 20%, more preferably 0.1 to 10%, and still more preferably 0.3 to 5%. When the mass ratio of the polyamine compound to the carboxyl group-containing acrylic rubber in the acrylic rubber composition of the present embodiment is 0.05% or more, the compression set resistance of the acrylic rubber crosslinked product is improved, and when it is 20% or less, the elongation at break of the acrylic rubber crosslinked product is improved.

< heteroatom containing alcohol >

The heteroatom-containing alcohol can improve the crosslinking adhesiveness of the acrylic rubber composition of the present embodiment to the fluororubber.

The heteroatom-containing alcohol is a compound in which a heteroatom is bonded to 1 or more hydroxyl groups via a 2-valent hydrocarbon group such as an alkylene group or an arylene group.

The hetero atom is not particularly limited, and examples thereof include a nitrogen atom, an oxygen atom, a sulfur atom, a chlorine atom and the like.

From the viewpoint of the crosslinking adhesiveness of the acrylic rubber composition of the present embodiment to fluororubber, the heteroatom-containing alcohol is preferably an aminoalcohol.

The aminoalcohol is not particularly limited, and includes monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-dimethylethanolamine, N-dibutylethanolamine, N-diethylethanolamine, N-methyl-N, N-diethanolamine, 2-amino-2-methylpropanol, 3-aminopropanol, 2-aminopropanol and the like. Among these, monoethanolamine, diethanolamine, and triethanolamine are preferable, diethanolamine, triethanolamine are more preferable, and triethanolamine is further preferable.

Examples of the hetero atom-containing alcohol other than the amino alcohol include 2-chloroethanol, 2-mercaptoethanol, and the like.

The hetero atom-containing alcohols may be used alone or in combination of two or more.

The mass ratio of the heteroatom alcohol to the carboxyl group-containing acrylic rubber in the acrylic rubber composition of the present embodiment is preferably 0.5 to 5%, more preferably 1 to 5%, even more preferably 1 to 4%, and particularly preferably 1 to 3%. When the mass ratio of the heteroatom alcohol to the carboxyl group-containing acrylic rubber in the acrylic rubber composition of the present embodiment is 0.5% or more, the crosslinking adhesiveness of the acrylic rubber composition to the fluororubber is improved, and when it is 5% or less, the compression set resistance of the acrylic rubber crosslinked product is improved.

< compounding Agents >

The acrylic rubber composition of the present embodiment may further contain, if necessary, a compounding agent generally used in the field of rubber processing.

Examples of the compounding agents include crosslinking accelerators, fillers, antioxidants, plasticizers, and processing aids.

As the crosslinking accelerator, known crosslinking accelerators can be used, and examples thereof include guanidine compounds, quaternary onium salts, tertiary phosphine compounds, alkali metal salts of weak acids, and the like.

As the filler, known fillers can be used, and examples thereof include carbon-based materials such as carbon black and Graphite (Graphite); metal powders such as aluminum powder; inorganic powders such as hard clay, talc, calcium carbonate, titanium oxide, calcium sulfate, calcium carbonate, and aluminum hydroxide; organic powders such as starch and polystyrene powder; short fibers such as glass fibers (milled fibers), carbon fibers, aromatic polyamide fibers, and potassium titanate whiskers; silica, mica, and the like.

Known antioxidants can be used as the antioxidant, and examples thereof include phenol compounds, amine compounds, phosphate compounds, and sulfur compounds.

As the plasticizer, known plasticizers can be used, and examples thereof include bis (butoxyethoxyethyl) adipate, bis (2-ethylhexyl) phthalate, adipic acid ether ester, polyether ester and the like.

As the processing aid, known processing aids can be used, and examples thereof include fatty acid-based waxes, fatty acid amide-based waxes, fatty acid ester-based waxes, fatty alcohol-based waxes, partial ester-based waxes of fatty acids and polyhydric alcohols, and the like.

< rubber, elastomer, and resin >

The acrylic rubber composition of the present embodiment may further contain a rubber, an elastomer, and a resin other than the acrylic rubber, as necessary.

The mass ratio of the rubber, elastomer, and resin other than the acrylic rubber in the acrylic rubber composition of the present embodiment to the acrylic rubber is preferably 50% or less, more preferably 30% or less, and still more preferably 10% or less.

Examples of the rubber other than the acrylic rubber include Natural Rubber (NR), Isoprene Rubber (IR), solution SBR (solution styrene butadiene rubber, emulsion SBR (emulsion styrene butadiene rubber), low-cis BR (butadiene rubber), high-cis BR, high-trans BR (trans bond content of butadiene moiety is 70 to 95%), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, ethylene-propylene-diene rubber (EPDM), emulsion styrene-acrylonitrile-butadiene copolymer rubber, polyisoprene-SBR block copolymer rubber, polystyrene-polybutadiene-polystyrene block copolymer, acrylic rubber, epichlorohydrin rubber, epoxy resin, epoxy, Fluororubbers, silicone rubbers, ethylene-propylene rubbers, urethane rubbers, and the like.

Examples of the elastomer include olefin elastomers, styrene elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, and polysiloxane elastomers.

Examples of the resin include olefin resins, styrene resins, acrylic resins, polyphenylene ethers, polyesters, polycarbonates, and polyamides.

< method for producing acrylic rubber composition >

In the production of the acrylic rubber composition of the present embodiment, a mixer such as a roll, a banbury mixer, a screw mixer, or the like can be suitably used.

< crosslinked rubber laminate >

In the crosslinked rubber laminate of the present embodiment, the acrylic rubber composition of the present embodiment and the fluororubber composition are crosslinked and bonded.

< fluororubber composition >

The fluororubber composition comprises a fluororubber and a crosslinking agent. Therefore, when the fluororubber composition is crosslinked, a crosslinked fluororubber product is formed.

< fluororubber >

The fluororubber is a homopolymer of a fluorine-containing monomer, a copolymer of two or more fluorine-containing monomers, or a copolymer of one or more fluorine-containing monomers and one or more monomers copolymerizable with the fluorine-containing monomers and not containing a fluorine atom.

Examples of the fluorine-containing monomer include crosslinkable monomers such as vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene, pentafluoropropylene, trifluoroethylene, chlorotrifluoroethylene, vinyl fluoride, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, and brominated and/or iodinated unsaturated fluorocarbons.

Examples of the monomer that does not contain a fluorine atom and is copolymerizable with the fluorine-containing monomer include ethylene and propylene.

Examples of the fluororubbers include binary copolymers such as vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-propylene copolymers, and tetrafluoroethylene-perfluoromethyl vinyl ether copolymers; terpolymers of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers; and copolymers of monomers constituting the terpolymer and a crosslinkable monomer.

The fluorine atom content in the fluororubber is preferably 65% by mass or more, more preferably 67% by mass or more, and still more preferably 69% by mass or more. When the fluorine atom content in the fluororubber is 65% by mass or more, the oil resistance, fuel oil resistance, and chemical resistance of the fluororubber crosslinked product are improved.

< crosslinking agent >

The crosslinking agent is not particularly limited as long as it can crosslink the fluororubber, and examples thereof include a polyol-based crosslinking agent, an organic peroxide-based crosslinking agent, and an amine-based crosslinking agent. Among these, from the viewpoint of crosslinking adhesiveness to the acrylic rubber composition, an organic peroxide-based crosslinking agent is preferable.

The crosslinking agent may be used alone, or two or more kinds may be used in combination.

Examples of the organic peroxide-based crosslinking agent include dialkyl peroxides such as dicumyl peroxide, di-t-butyl peroxide, 2, 5-dimethyl-2, 5-bis (t-butylperoxy) -3-hexyne, 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexane, and 1, 3-bis (t-butylperoxyisopropyl) benzene; diacyl peroxides such as benzoyl peroxide and isobutyryl peroxide; and peroxyesters such as 2, 5-dimethyl-2, 5-bis (benzoyl peroxide) hexane and t-butylperoxyisopropyl carbonate. Among these, 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexane is preferred.

The mass ratio of the crosslinking agent to the fluororubber is preferably 0.01 to 10%, more preferably 0.05 to 5%, and still more preferably 0.1 to 5%. When the mass ratio of the crosslinking agent to the fluororubber is 0.01% or more, the compression set resistance of the fluororubber crosslinked product is improved, and when it is 10% or less, the elongation at break of the fluororubber crosslinked product is improved.

< compounding Agents >

The fluororubber composition may further contain a compounding agent generally used in the field of rubber processing, if necessary.

Examples of the compounding agent include a crosslinking assistant and a filler.

As the crosslinking assistant, a known crosslinking assistant can be used, and examples thereof include triallyl isocyanurate and the like.

As the filler, known fillers can be used, and examples thereof include carbon-based materials such as carbon black and Graphite (Graphite); metal powders such as aluminum powder; inorganic powders such as hard clay, talc, calcium carbonate, titanium oxide, calcium sulfate, calcium carbonate, and aluminum hydroxide; organic powders such as starch and polystyrene powder; short fibers such as glass fibers (milled fibers), carbon fibers, aromatic polyamide fibers, and potassium titanate whiskers; silica, mica, and the like.

< method for producing fluororubber composition >

In the production of the fluororubber composition, a mixer such as a roll, a Banbury mixer, or a screw mixer can be suitably used.

< method for producing crosslinked rubber laminate >

The crosslinked rubber laminate can be produced by, for example, the following method.

First, the acrylic rubber composition and the fluororubber composition are molded into a sheet shape, respectively, or the acrylic rubber composition and the fluororubber composition are molded into a laminated pipe by a layer extrusion method to produce a molded body.

As the method for molding the acrylic rubber composition and the fluororubber composition, known methods such as press molding, roll molding, and extrusion molding can be used.

The thickness of the molded article of the acrylic rubber composition and the fluororubber composition is preferably 0.1 to 5mm, and more preferably 0.5 to 3 mm.

The thicknesses of the molded articles of the acrylic rubber composition and the fluororubber composition may be the same or different.

Next, the molded article of the acrylic rubber composition and the molded article of the fluororubber composition are crosslinked and bonded by heating and pressing with a hot press or a vulcanizing tank in a state where they are in contact with each other, whereby a crosslinked rubber laminate can be produced.

When a hot press is used, the pressure is usually increased at 0.2 to 15MPa and the temperature is increased at 140 to 200 ℃ for 5 to 60 minutes.

In addition, when a vulcanizing tank is used, the pressure is increased at 0.18MPa and the temperature is increased at 130 to 160 ℃ for 30 to 120 minutes.

Further, the crosslinked rubber laminate can be produced by subjecting a molded article of the acrylic rubber composition and a molded article of the fluororubber composition to primary crosslinking in a state where they are in contact with each other, and then subjecting them to secondary crosslinking by heat treatment (post-cure). This shortens the time required for primary crosslinking, and improves the compression set resistance of the crosslinked rubber laminate.

The crosslinked rubber laminate of the present embodiment is not limited to a structure in which an acrylic rubber crosslinked product and a fluororubber crosslinked product are laminated layer by layer, and may have a structure in which an acrylic rubber composition and a fluororubber composition are crosslinked and bonded, and may have a plurality of layers of acrylic rubber crosslinked products and/or fluororubber crosslinked products.

The crosslinked rubber laminate of the present embodiment may further include the following layers: the layer contains a crosslinked product of a rubber other than the acrylic rubber and the fluororubber.

Examples of the rubber other than the acrylic rubber and the fluororubber include epichlorohydrin rubber, acrylonitrile-butadiene rubber, a mixed rubber of acrylonitrile-butadiene rubber and polyvinyl chloride, and chlorosulfonated polyethylene rubber.

Applications of the crosslinked rubber laminate of the present embodiment include sealing materials such as O-rings, gaskets, oil seals, and bearing seals in a wide range of fields such as transportation machines such as automobiles, general-purpose equipment, and electric equipment; oil pipes, fuel pipes, air pipes, turbine air pipes, PCV pipes, intake pipes, and the like; industrial belts such as transmission belts and endless belts; cushioning materials, shock-proof materials; a wire coating material; sheet material; a shield; dust covers, and the like. Among these, the fuel pipe is particularly preferable.