JP6398799B2 - Rubber laminate and hose - Google Patents

Description

  The present invention relates to a rubber laminate formed by crosslinking and bonding an acrylic rubber layer made of an acrylic rubber composition and a fluororubber layer made of a fluororubber composition, and a hose using the rubber laminate.

  Fluoro rubber is excellent in heat resistance, oil resistance, solvent resistance, chemical resistance, and the like, and is widely used in various fields such as the automobile industry, semiconductor industry, and chemical industry. For example, for automobile applications, it is used as an engine and peripheral devices, AT devices, fuel systems and peripheral devices such as hoses, sealing materials, and the like.

  However, since fluororubber is expensive, hoses and seals are not made of fluororubber alone. For example, when manufacturing a fuel hose or air hose, fluororubber is used as the inner thin layer, Has a laminated structure using rubber having excellent cold resistance and weather resistance.

  For example, Patent Document 1 describes a rubber laminate in which an acrylic rubber layer containing an epoxy group-containing acrylic rubber, a specific amount of a phosphonium salt and a metal salt of dithiocarbamate and a fluororubber layer are bonded together.

Japanese Patent Laying-Open No. 2015-3487

  By the way, in recent years, vehicles equipped with a turbocharger system have been widely used in response to exhaust gas regulations. Deteriorated oil and fuel mists flow along with hot air in air hoses (hereinafter sometimes referred to as “turbo hoses”) used in turbocharger systems. For this reason, it is difficult to use the rubber laminate described in Patent Document 1 for applications that require high heat resistance such as turbo hose, and the excellent heat resistance, oil resistance, fuel oil resistance, and acid resistance of fluororubbers. There was a possibility that it could not be fully utilized. Therefore, in addition to the cross-linking adhesiveness, the rubber laminate used for such applications is required to have heat resistance further superior to that of the rubber laminate described in Patent Document 1.

  An object of the present invention has been made in view of such circumstances, and is a rubber laminate formed by crosslinking and bonding an acrylic rubber layer made of an acrylic rubber composition and a fluororubber layer made of a fluororubber composition. The object is to provide a rubber laminate having improved heat resistance and excellent cross-linking adhesion between the acrylic rubber layer and the fluororubber layer, and a hose using the rubber laminate.

As a result of intensive studies to solve the above problems, the present inventors have achieved the above object by using an acrylic rubber composition containing an acrylic rubber containing a specific functional group and a fluororubber composition containing a specific crosslinking agent. The present inventors have found that the present invention can be accomplished and have completed the present invention.
That is, according to the present invention,

(1) An acrylic rubber layer (A) comprising an acrylic rubber composition containing an acrylic rubber (a1) having a phenolic hydroxyl group as a crosslinking point, and a fluororubber containing a fluororubber (b1) and a polyol cross-linking agent (b2) A rubber laminate obtained by crosslinking and bonding the fluororubber layer (B) comprising the composition;
(2) The rubber laminate according to (1), wherein the acrylic rubber composition further contains a fluororubber (a2),
(3) A hose using the rubber laminate according to (1) or (2) is provided.

  According to the present invention, there is provided a rubber laminate obtained by crosslinking and bonding an acrylic rubber layer made of an acrylic rubber composition and a fluororubber layer made of a fluororubber composition, the heat resistance is improved, and the acrylic rubber Provided are a rubber laminate excellent in the cross-linking adhesion between the layer and the fluororubber layer, and a hose using the rubber laminate.

  Hereinafter, the laminate of the present invention will be described. The rubber laminate of the present invention comprises an acrylic rubber layer (A) comprising an acrylic rubber composition containing an acrylic rubber (a1) having a phenolic hydroxyl group as a crosslinking point, a fluororubber (b1), and a polyol crosslinking agent (b2). And a fluororubber layer (B) made of a fluororubber composition containing

(Acrylic rubber layer (A))
The acrylic rubber layer (A) is composed of an acrylic rubber composition containing an acrylic rubber (a1) having a phenolic hydroxyl group as a crosslinking point (hereinafter sometimes referred to as “phenolic hydroxyl group-containing acrylic rubber (a1)”). . The acrylic rubber composition preferably further contains a fluororubber (a2).

(Phenolic hydroxyl group-containing acrylic rubber (a1))
The acrylic rubber (a1) having a phenolic hydroxyl group as a crosslinking point for use in the present invention contains a (meth) acrylic acid ester monomer unit and a (meth) acrylic acid ester monomer as a main component. preferable. In the present specification, “(meth) acryl” means both “acryl” and “methacryl”.

  (Meth) acrylic acid ester monomers include (meth) acrylic acid alkyl ester monomers, (meth) acrylic acid alkoxyalkyl ester monomers, and the like.

  From the viewpoint of improving oil resistance, the (meth) acrylic acid alkyl ester monomer is, for example, a (meth) acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms, preferably 2 to 2 carbon atoms. (Meth) acrylic acid alkyl ester monomers having 4 alkyl groups.

  Specific examples of the (meth) acrylic acid alkyl ester monomer having an alkyl group having 1 to 8 carbon atoms include, for example, 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, cyclohexyl (meth) acrylate and (meth ) Octyl acrylate and the like. Of these, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferred from the viewpoint of a good balance of heat resistance, oil resistance and cold resistance. These (meth) acrylic acid alkyl esters may be used alone or in combination of two or more.

  Although it does not specifically limit as a (meth) acrylic-acid alkoxyalkylester monomer, From a viewpoint of improving oil resistance, it has a C1-C4 alkoxy group and a C1-C4 alkylene group, for example (meta) ) Alkoxyalkyl esters of acrylic acid. Examples of the (meth) acrylic acid alkoxyalkyl ester having an alkoxy group having 1 to 4 carbon atoms and an alkylene group having 1 to 4 carbon atoms include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, Examples include 2-butoxyethyl (meth) acrylate and 2-methoxypropyl (meth) acrylate. Of these, 2-methoxyethyl (meth) acrylate and 2-butoxyethyl (meth) acrylate are preferred from the viewpoint of a good balance of heat resistance, oil resistance and cold resistance. One of these (meth) acrylic acid alkoxyalkyl esters may be used alone, or two or more thereof may be used in combination.

  The content of the (meth) acrylic acid ester monomer unit in the monomer unit constituting the phenolic hydroxyl group-containing acrylic rubber (a1) is such that the resulting acrylic rubber has good rubber elasticity and a sufficient crosslinking density is obtained. In view of the above, it is preferably 60 to 99.9% by weight, more preferably 92 to 99.7% by weight, and still more preferably 92 to 99.5% by weight.

  Moreover, the phenolic hydroxyl group-containing acrylic rubber (a1) used in the present invention has a phenolic hydroxyl group as a crosslinking point. The phenolic hydroxyl group in the phenolic hydroxyl group-containing acrylic rubber (a1) functions as a crosslinkable group and crosslinks with the fluororubber. Therefore, fluororubber has a function as a crosslinking agent when used in an acrylic rubber composition described later. The phenolic hydroxyl group-containing acrylic rubber (a1) can be obtained, for example, by copolymerization using the above (meth) acrylic acid alkyl ester monomer and a phenolic hydroxyl group-containing monomer unit.

  The phenolic hydroxyl group-containing monomer is not particularly limited as long as it is a monomer that contains a phenolic hydroxyl group and is copolymerizable with a (meth) acrylic acid ester monomer. Examples of the phenolic hydroxyl group-containing monomer include o, m, p-hydroxystyrene, α-methyl-o-hydroxystyrene, o-cabicol, vinyl p, m-hydroxybenzoate, 4-hydroxybenzyl (meth) acrylate, Vinyl salicylate, vinyl p-hydroxybenzoyloxyacetate, eugenol, isoeugenol, p-isopropenylphenol, o, m, p-allylphenol, 4-hydroxyphenyl (meth) acrylate, 2,2- (o, m, p-hydroxyphenyl-4-vinylacetyl) propane and the like. These phenolic hydroxyl group-containing monomers may be used alone or in combination of two or more.

  The content of the phenolic hydroxyl group-containing monomer unit in all the monomer units constituting the phenolic hydroxyl group-containing acrylic rubber (a1) is preferably 0.1 to 10% by weight, more preferably 0.3 to 8%. % By weight, more preferably 0.5 to 5% by weight. If the content of the phenolic hydroxyl group-containing monomer is too small, the crosslinking density of the rubber cross-linked product is not sufficient, and good mechanical properties cannot be obtained. On the other hand, if the content of the phenolic hydroxyl group-containing monomer is too large, the elongation of the crosslinked product is lowered.

  The phenolic hydroxyl group-containing acrylic rubber (a1) used in the present invention is a unit other than the (meth) acrylic acid ester monomer unit and the phenolic hydroxyl group-containing monomer unit as long as the effects of the present invention are not essentially impaired. It may contain a monomer unit. As the monomer forming such a monomer unit, a (meth) acrylic acid ester monomer and another monomer copolymerizable with a phenolic hydroxyl group-containing monomer can be used.

  Specifically, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid; complete or partial of unsaturated polycarboxylic acid such as itaconic acid, fumaric acid and maleic acid and lower alcohol Esterified product: Styrene, vinyl toluene, vinyl pyridine, α-methyl styrene, chloromethyl styrene, ethylene propylene, acrylonitrile, methacrylonitrile, acrylamide, N-methylol acrylamide, 2-chloroethyl vinyl ether, monochlorovinyl acetate, allyl chloride, acetic acid Examples include vinyl and vinyl chloride. These other monomers may be used individually by 1 type, and may use 2 or more types together.

  The content of monomer units other than the (meth) acrylic acid ester monomer unit and the phenolic hydroxyl group-containing monomer unit is preferably among all monomer units constituting the phenolic hydroxyl group-containing acrylic rubber (a1). Is 30% by weight or less, more preferably 7.7% by weight or less, and further preferably 4.5% by weight or less.

  The phenolic hydroxyl group-containing acrylic rubber (a1) used in the present invention can be obtained by polymerizing the above monomers. As the form of the polymerization reaction, any of an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, and a solution polymerization method can be used. From the viewpoint of easy control of the polymerization reaction, a conventionally known acrylic rubber It is preferable to use an emulsion polymerization method under normal pressure, which is generally used as a production method of the above.

  The emulsion polymerization may be any of batch, semi-batch and continuous. The polymerization is usually performed in a temperature range of 0 to 70 ° C, preferably 5 to 50 ° C. After polymerization, the solid phenolic hydroxyl group-containing acrylic rubber (a1) is obtained through solidification and drying.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) (polymer Mooney) of the thus produced phenolic hydroxyl group-containing acrylic rubber (a1) is preferably 10 to 80, more preferably 20 to 70, even more preferably. Is 25-60.

(Fluoro rubber (a2))
As fluororubber (a2), what is illustrated in the fluororubber (b1) contained in the fluororubber layer (B) mentioned later can be used.

  The fluororubber (a2) may be liquid fluororubber. Here, the liquid fluororubber is not particularly limited as long as it is liquid fluororubber at room temperature (20 ° C.).

  For example, vinylidene fluoride / hexane fluoropropylene copolymer, vinylidene fluoride-hexafluoropentene-tetrafluoroethylene terpolymer, perfluoropropene oxide polymer, tetrafluoroethylene-propylene-vinylidene fluoride copolymer, etc. Is mentioned. As these liquid fluororubbers, commercially available Viton (registered trademark) LM (manufactured by DuPont), Daiel (registered trademark) G101 (manufactured by Daikin Industries, Ltd.), Dinion FC2210 (manufactured by 3M) and the like can be used. .

  Here, the viscosity of the liquid fluororubber is not particularly limited, but the viscosity at 105 ° C. is preferably 500 to 30,000 cps from the viewpoint of good kneadability, fluidity and crosslinking reactivity, and excellent moldability. More preferably, it is 550-25,000 cps.

  The blending amount of the fluororubber (a2) is preferably 0.4 to 50 parts by weight, more preferably 100 parts by weight with respect to 100 parts by weight of the phenolic hydroxyl group-containing acrylic rubber (a1), from the viewpoint of obtaining an appropriate crosslinking rate. It is 0.5-40 weight part, More preferably, it is 1.0-20 weight part.

(Acrylic rubber composition)
The acrylic rubber composition used in the present invention comprises the phenolic hydroxyl group-containing acrylic rubber (a1) and a compounding agent. The acrylic rubber composition of the present invention is preferably a crosslinkable acrylic rubber composition containing fluororubber (a2) as a compounding agent. Further, as a compounding agent, in addition to the fluororubber (a2), an acid acceptor, a crosslinking accelerator, and the like may be further contained.

(Acid acceptor)
Examples of the acid acceptor used in the acrylic rubber composition include magnesium oxide, calcium oxide, zinc oxide, calcium silicate, calcium hydroxide, zinc hydroxide, aluminum hydroxide, and hydrotalcite. Among these, it is preferable to use calcium silicate as an acid acceptor from the viewpoint of good storage stability of the acrylic rubber composition. The amount of the acid acceptor is not particularly limited, but is preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight, and still more preferably 2 to 14 parts by weight with respect to 100 parts by weight of the acrylic rubber. Particularly preferred is 6 to 12 parts by weight. If the amount of the acid acceptor is too small, a sufficient crosslinking rate tends not to be obtained. Moreover, when there is too much quantity of an acid acceptor, the hardness of a rubber crosslinked material may become high too much.

(Crosslinking accelerator)
The rubber cross-linked product preferably contains a cross-linking accelerator from the viewpoint of exhibiting an appropriate cross-linking rate. Examples of the crosslinking accelerator include quaternary ammonium salts and quaternary phosphonium salts.

  Examples of the quaternary ammonium salt include tetrabutylammonium hydrogen sulfate, tetrapropylammonium hydride oxide, tetrabutylammonium hydride oxide, trimethylphenylammonium chloride, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyltributylammonium chloride, and tetramethyl. Ammonium chloride, tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, n-dodecyltrimethylammonium chloride, n-dodecyltrimethylammonium bromide, octadecyltrimethylammonium bromide , Cetyl dimethyl ammonium chloride, 1,6-diaza - bicyclo (5.4.0) undecene-7-cetyl pyridinium sulfate, etc. trimethylbenzylammonium benzoate.

  Examples of the quaternary phosphonium salt include triphenylbenzylphosphonium chloride, triphenylbenzylphosphonium bromide, tricyclohexylbenzylphosphonium chloride, tricyclohexylbenzylphosphonium bromide and the like. These crosslinking accelerators may be used alone or in combination of two or more.

  The compounding amount of the crosslinking accelerator is usually 0.1 to 5 parts by weight, preferably 0.2 to 2 parts by weight with respect to 100 parts by weight of the acrylic rubber. If the blending amount of the crosslinking accelerator is too small, a sufficient crosslinking rate tends to be difficult to obtain. Moreover, when there are too many compounding quantities of a crosslinking accelerator, scorch stability may be impaired.

(Other ingredients)
The acrylic rubber composition may contain various auxiliary materials added to the normal acrylic rubber composition in addition to the components of the above-described compounding agent depending on the purpose. Examples of such auxiliary materials include, but are not limited to, reinforcing materials, fillers, anti-aging agents, lubricants, plasticizers, stabilizers, and pigments.

  Examples of the reinforcing material include carbon black and silica. Moreover, it is preferable that an acrylic rubber composition contains a reinforcing material from a viewpoint of improving the intensity | strength of a rubber crosslinked material. The compounding amount of the reinforcing material is usually 10 to 100 parts by weight, preferably 30 to 90 parts by weight with respect to 100 parts by weight of the acrylic rubber.

When the acrylic rubber composition contains silica as a reinforcing material, it is preferable to add a silane coupling agent to the acrylic rubber composition from the viewpoint of improving the strength of the rubber cross-linked product.
Examples of the filler include carbon black, calcium carbonate, kaolin clay, and talc diatomaceous earth.

（上記一般式（１）中、Ｙは−ＳＯ₂−を表す。Ｒ^aおよびＲ^bはそれぞれ独立して、炭素数１〜３０の炭化水素基を表す。Ｚ^aおよびＺ^bはそれぞれ独立して、化学的な単結合または、−ＳＯ₂−を表す。ｎおよびｍはそれぞれ独立して、０または１であり、ｎおよびｍの少なくとも一方は１である。） Examples of the antiaging agent include diphenylamine derivatives and phenylenediamine derivatives. Especially, it is preferable to mix | blend the compound shown by following General formula (1) as an anti-aging agent from a viewpoint of improving the heat resistance of a rubber crosslinked material.

(In the general formula (1), Y represents —SO ₂ —. R ^a and R ^b each independently represent a hydrocarbon group having 1 to 30 carbon atoms. Z ^a and Z ^b each independently represent And represents a chemical single bond or —SO ₂ —, wherein n and m are each independently 0 or 1, and at least one of n and m is 1.

Although it does not specifically limit as a C1-C30 hydrocarbon group which comprises R ^<a> and R < ^b >, For example, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec An alkyl group having 1 to 30 carbon atoms such as -butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group and n-decyl group; A cycloalkyl group having 3 to 30 carbon atoms such as propyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group; phenyl group, benzyl group, α-methylbenzyl group, α, α-dimethylbenzyl group, 4- Examples thereof include aryl groups having 6 to 30 carbon atoms such as a methylphenyl group, a biphenyl group, a naphthyl group, and an anthranyl group.

In the present invention, R ^a and R ^b are each independently preferably ^a linear or branched alkyl group having 2 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. Alternatively, a branched alkyl group having 2 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms is more preferable.

Preferable specific examples of the hydrocarbon group constituting R ^a and R ^b include α-methylbenzyl group, α, α-dimethylbenzyl group, t-butyl group, phenyl group, 4-methylphenyl group and the like. Is mentioned. Among these, an α, α-dimethylbenzyl group or a 4-methylphenyl group is more preferable, and an α, α-dimethylbenzyl group is more preferable.
The compound of the general formula (1) can be synthesized by the method described in International Publication No. 2011/093443.
Although the compounding quantity of an antioxidant is not specifically limited, It is 0.1-10 weight part normally with respect to 100 weight part of acrylic rubber, Preferably it is 0.5-5 weight part.
Examples of the lubricant include organosilicone compounds, paraffin, hydrocarbon resin, fatty acid, fatty acid amide, fatty acid ester, fatty acid alcohol and the like.
Examples of the plasticizer include phthalic acid derivatives, adipic acid derivatives, and polyether ester derivatives.
Examples of the stabilizer include phthalic anhydride, benzoic acid, N- (cyclohexylthio) phthalimide, and sulfonamide derivatives.

  Examples of the pigment include titanium oxide, carbon black, and cyanine blue. When the acrylic rubber composition contains silica, the acrylic rubber composition may contain 5 parts by weight or less of carbon black with respect to 100 parts by weight of the acrylic rubber for the purpose of coloring the acrylic rubber composition.

  The preparation method of an acrylic rubber composition is not specifically limited, A well-known preparation method can be used. For example, an acrylic rubber composition can be prepared by kneading each compounding component with an open roll, an internal mixer or the like usually used in the rubber industry.

(Fluoro rubber layer (B))
A fluororubber layer (B) consists of a fluororubber composition containing a fluororubber (b1) and a polyol crosslinking agent (b2).

(Fluoro rubber (b1))
As the fluororubber (b1), a homopolymer rubber of a fluorine-containing unsaturated monomer, a copolymer rubber of a fluorine-containing unsaturated monomer, or another monomer copolymerizable with the fluorine-containing unsaturated monomer And copolymer rubber with the body. Examples of the fluorine-containing unsaturated monomer for forming the fluororubber (b1) include vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene, pentafluoropropylene, trifluoroethylene, trifluorochloroethylene, vinyl fluoride, par Examples thereof include fluoromethyl vinyl ether and perfluoroethyl vinyl ether. Examples of other monomers copolymerizable with the fluorine-containing unsaturated monomer include ethylene, propylene, and olefin bromide that is a crosslinkable monomer.

  Among these, a copolymer rubber containing a vinylidene fluoride [VdF] unit and a copolymer unit derived from another comonomer is preferable.

  Further, the content of the VdF unit in the fluororubber (b1) is preferably 20 mol% or more with respect to the total number of moles of the VdF unit and the polymerized unit derived from other comonomer, and is 45 mol. % Or more is more preferable, and it is further more preferable that it is 55 mol% or more. Further, the content of the VdF unit in the fluororubber (b1) is preferably 85 mol% or less, based on the total number of moles of the VdF unit and the polymerized unit derived from other comonomer, and is 80 mol. % Or less is more preferable.

  The content of the polymerized units derived from other comonomer in the fluororubber (b1) is 15 mol% with respect to the total number of moles of VdF units and polymerized units derived from the other comonomer. It is preferable that it is more than 20 mol%. The content of polymerized units derived from other comonomer in the fluororubber (b1) is 80 mol% with respect to the total number of moles of VdF units and polymerized units derived from other comonomer. The content is preferably less than, more preferably 55 mol% or less, and even more preferably 45 mol% or less.

  Other comonomer is not particularly limited as long as it can be copolymerized with VdF. For example, hexafluoropropylene [HFP], tetrafluoroethylene [TFE], trifluorochloroethylene [CTFE], perfluoro (alkyl) Vinyl ether) [PAVE], trifluoroethylene, trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, hexafluoroisobutene, vinyl fluoride, and other fluorine-containing monomers; ethylene [Et], Non-fluorine-containing monomers such as propylene [Pr] and alkyl vinyl ethers can be used, and these monomers and compounds can be used alone or in combination of two or more.

  Examples of PAVE include perfluoro (methyl vinyl ether) [PMVE], perfluoro (ethyl vinyl ether) [PEVE], perfluoro (propyl vinyl ether) [PPVVE], and the like.

  Among these, a copolymer rubber containing a copolymer unit derived from a VdF unit and a fluorine-containing monomer (excluding VdF) is preferable. It is also preferable to include a copolymer unit derived from a monomer that can be copolymerized with a copolymer unit derived from a VdF unit and a fluorine-containing monomer.

  Examples of the copolymer containing a VdF unit and a copolymer unit derived from a fluorine-containing monomer include a VdF / HFP copolymer, a VdF / TFE / HFP copolymer, a VdF / CTFE copolymer, and a VdF / CTFE / TFE copolymer. Polymer, VdF / PAVE copolymer, VdF / TFE / PAVE copolymer, VdF / HFP / PAVE copolymer, VdF / HFP / TFE / PAVE copolymer, VdF / TFE / Pr copolymer, VdF / Et / HFP copolymer and the like can be mentioned.

  Among these, the VdF / HFP copolymer, VdF / HFP / TFE copolymer are used from the viewpoint that the acrylic rubber layer (A) and the fluororubber layer (B) are more firmly bonded, heat resistance, cold resistance, and oil resistance. Preferably, at least one selected from the group consisting of a polymer, a VdF / PAVE copolymer, a VdF / TFE / PAVE copolymer, a VdF / HFP / PAVE copolymer, and a VdF / HFP / TFE / PAVE copolymer. More preferred is at least one selected from the group consisting of VdF / HFP copolymer and VdF / HFP / TFE copolymer. The said fluororubber (b1) may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the VdF / HFP copolymer, the composition of VdF / HFP is preferably (45 to 85) / (55 to 15) (mol%), and (50 to 80) / (50 to 20) (mol%). It is more preferable that it is (60-80) / (40-20) (mol%).

  In the VdF / TFE / HFP copolymer, the composition of VdF / TFE / HFP is preferably (30-80) / (4-35) / (10-35) (mol%), (45-80 ) / (5-20) / (15-35) (mol%).

  The VdF / PAVE copolymer preferably has a VdF / PAVE composition of (65 to 90) / (35 to 10) (mol%).

  The VdF / TFE / PAVE copolymer preferably has a VdF / TFE / PAVE composition of (40-80) / (3-40) / (15-35) (mol%).

  The VdF / HFP / PAVE copolymer preferably has a VdF / HFP / PAVE composition of (65 to 90) / (3 to 25) / (3 to 25) (mol%).

  As a VdF / HFP / TFE / PAVE copolymer, the composition of VdF / HFP / TFE / PAVE is (40-90) / (0-25) / (0-40) / (3-35) (mol% It is preferable that it is (40-80) / (3-25) / (3-40) / (3-25) (mol%).

(Polyol crosslinking agent (b2))
As the polyol crosslinking agent (b2) used in the present invention, the acrylic rubber layer (A) and the fluororubber layer (B) are more firmly bonded, and the compression set of the vulcanized fluororubber (b1) is compression set. A polyhydroxy compound is preferable from the viewpoint of excellent moldability, and a polyhydroxy aromatic compound is particularly preferable from the viewpoint of excellent heat resistance.

  The polyhydroxy aromatic compound is not particularly limited, and examples thereof include 2,2-bis (4-hydroxyphenyl) propane (hereinafter sometimes referred to as “bisphenol A”), 2,2-bis (4-hydroxy). Phenyl) perfluoropropane (hereinafter sometimes referred to as “bisphenol AF”), resorcin, 1,3-dihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4 , 4′-dihydroxydiphenyl, 4,4′-dihydroxystilbene, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis (4-hydroxyphenyl) butane, 4,4-bis (4-hydroxyphenyl) Valeric acid, 2,2-bis (4-hydroxyphenyl) te Lafluorodichloropropane, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenyl ketone, tri (4-hydroxyphenyl) methane, 3,3 ′, 5,5′-tetrachlorobisphenol A, 3,3 Examples include ', 5,5'-tetrabromobisphenol A. Among these, bisphenol AF is particularly preferable because the acrylic rubber layer (A) and the fluororubber layer (B) are more firmly bonded.

  These polyhydroxy aromatic compounds may be alkali metal salts, alkaline earth metal salts, and the like. However, when coagulating the copolymer using an acid, the above metal salts may not be used. preferable.

  The blending amount of the polyol crosslinking agent (b2) in the fluororubber composition used in the present invention is preferably 0.2 to 10 parts by weight, more preferably 0 with respect to 100 parts by weight of the fluororubber (b1). 0.5-6 parts by weight, more preferably 1-4 parts by weight. When the blending amount of the polyol crosslinking agent (b2) is too low, the crosslinking of the fluororubber (b1) becomes insufficient and the compression set resistance tends to be inferior. On the other hand, if the blending amount of the polyol crosslinking agent (b2) is too high, the crosslinking density becomes too high, so that the elongation of the fluororubber layer (B) after crosslinking is lowered and tends to be easily broken during compression.

(Crosslinking accelerator)
The fluororubber composition may contain a crosslinking accelerator in addition to the fluororubber (b1) and the polyol crosslinking agent (b2). When a crosslinking accelerator is used, the crosslinking reaction can be promoted by promoting the formation of intramolecular double bonds in the dehydrofluorination reaction of the fluororubber main chain and the addition of polyhydroxy compounds to the generated double bonds. it can. Examples of the crosslinking accelerator include quaternary ammonium salts and quaternary phosphonium salts.

  Examples of the quaternary ammonium salt and the quaternary phosphonium salt include those that can be used for the crosslinking accelerator preferably contained in the acrylic rubber composition. Moreover, these crosslinking accelerators may be used individually by 1 type, and may use 2 or more types together.

  The amount of the crosslinking accelerator used is preferably 0.01 to 8 parts by weight and more preferably 0.02 to 5 parts by weight with respect to 100 parts by weight of the fluororubber (b1). preferable. When there is too much compounding quantity of a crosslinking accelerator, there exists a tendency for the balance of a physical property to fall.

(Acid acceptor)
From the viewpoint of improving acid resistance, the fluororubber composition used in the present invention includes, as an acid acceptor, a metal oxide, a metal hydroxide, a weak acid salt of an alkali metal, and a weak acid salt of an alkaline earth metal. It preferably contains at least one selected compound.

  Metal oxides, metal hydroxides, alkali metal weak acid salts and alkaline earth metal weak acid salts include Group II metal oxides, hydroxides, carbonates, carboxylates and silicates. , Borate, phosphite, periodic table group (IV) metal oxide, basic carbonate, basic carboxylate, basic phosphite, basic sulfite and the like.

Specifically, magnesium oxide, magnesium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, calcium oxide (quick lime), calcium hydroxide (slaked lime), calcium carbonate, calcium silicate, calcium stearate, zinc stearate, phthalic acid Calcium, calcium phosphite, tin oxide, basic tin phosphite and the like can be mentioned.
Among these, it is more preferable that the fluororubber composition contains magnesium oxide and calcium hydroxide.

  The content of the metal oxide, metal hydroxide, alkali metal weak acid salt, alkaline earth metal weak acid salt is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, with respect to 100 parts by weight of the fluororubber. It is. Moreover, the lower limit of content is not specifically limited.

(filler)
The fluororubber composition preferably contains a filler such as carbon black or silica. Carbon black is preferred as the filler. Examples of carbon black include furnace black, acetylene black, thermal black, channel black, and graphite. These carbon blacks may be used alone or in combination of two or more.

  The blending amount of carbon black in the fluororubber composition is preferably 0 to 50 parts by weight with respect to 100 parts by weight of the fluororubber (b1), more preferably 5 to 40 parts by weight from the viewpoint of good physical property balance, 10-30 weight part is further more preferable. When there is too much content of carbon black, the hardness of a molded article will rise and it will become the tendency for a softness | flexibility to fall. Moreover, when there is too little content of carbon black, a mechanical physical property may fall.

  In addition to the above components, the fluororubber composition may contain a compounding agent that is usually used in the rubber field, if necessary. Examples of compounding agents include anti-aging agents, light stabilizers, plasticizers, processing aids, lubricants, adhesives, lubricants, flame retardants, antifungal agents, antistatic agents, colorants, silane coupling agents, and crosslinking agents. Examples include retarders. Moreover, you may mix | blend other polymers, such as polyethylene, a polypropylene, polyamide, polyester, a polyurethane, etc. in the range which does not impair the effect of this invention.

  The compounding amount of these compounding agents is not particularly limited as long as it does not impair the object and effect of the present invention, and an amount corresponding to the compounding purpose can be appropriately compounded.

  The fluororubber composition used in the present invention is prepared by kneading fluororubber (b1), polyol cross-linking agent (b2), cross-linking accelerator, acid acceptor, filler and other compounding agents used as necessary according to a conventional method. For example, it can be obtained by kneading using a generally used rubber kneading apparatus. As the rubber kneader, rolls, kneaders, Banbury mixers, internal mixers, twin screw extruders, and the like can be used.

(Rubber laminate)
The rubber laminate of the present invention is a rubber laminate obtained by crosslinking and bonding the acrylic rubber layer (A) made of the above-described acrylic rubber composition and the fluororubber layer (B) made of the fluororubber composition.

  Although the manufacturing method of the rubber laminated body of this invention is not limited, For example, it can manufacture by the following method. That is, first, the acrylic rubber composition and the fluororubber composition described above are separately separated from each other by a known method such as press molding, roll molding, extrusion molding, and the thickness is preferably 0.1 to 5 mm, more preferably 0. It is molded into a sheet having an arbitrary area of 5 to 3 mm (acrylic rubber layer (A) sheet, fluororubber layer (B) sheet) in an uncrosslinked state. Next, the rubber laminate of the present invention can be obtained by bringing the obtained sheets into contact with each other, followed by pressure-heat crosslinking using a hot press or a vulcanizing can and bonding them.

  Alternatively, a method in which the acrylic rubber composition and the fluororubber composition are molded into a laminated tube in an uncrosslinked state by a layer extrusion method, and then subjected to pressure-heat crosslinking using a vulcanizing can and bonded. Also good.

  Hot pressing is usually performed at a temperature of 140 to 200 ° C. and a pressure of 0.2 to 15 MPa for 5 to 60 minutes. Moreover, when using a vulcanizing can, it is normally performed for 30 to 120 minutes under the pressure of 0.18 MPa at the temperature of 130-160 degreeC.

  In addition, by further heat-treating (post-cure) the resulting rubber laminate, it is possible to shorten the crosslinking time for crosslinking (primary crosslinking) and to improve the compression set resistance of the rubber laminate. is there.

  The rubber laminate of the present invention is not limited to the form in which the acrylic rubber layer (A) and the fluororubber layer (B) are laminated one by one, as long as they have portions laminated alternately. One or both of these may be formed in a plurality of layers. Moreover, you may have the other layer which consists of another material. As the above-mentioned other materials, suitable materials may be selected according to required characteristics and intended use. For example, epichlorohydrin rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene rubber and polyvinyl chloride. And blend rubber, chlorosulfonated polyethylene rubber and the like.

  The rubber laminate of the present invention thus obtained has good normal physical properties and heat resistance, and has a cross-linking adhesive property between the layers constituting the rubber laminate (cross-linked acrylic rubber layer (A) and fluorine). It is excellent in cross-linking adhesiveness with the rubber layer (B). Therefore, the rubber laminate of the present invention can be suitably used for hose applications. In particular, since the rubber laminate of the present invention is excellent in heat resistance, hoses used in the automotive field, such as turbocharger hoses, intercooler hoses, air duct hoses, air intake hoses, emission control hoses, vacuum hoses, or positive cranks. It can be suitably used as a ventilation (PCV) hose.

  The rubber laminate of the present invention can improve the adhesion between the acrylic rubber layer (A) and the fluororubber layer (B) in the rubber laminate by the acrylic rubber (a1) containing a phenolic hydroxyl group. . Further, it is not necessary to use a special additive such as an adhesive for bonding the acrylic rubber layer (A) and the fluororubber layer (B).

  Here, since the phenolic hydroxyl group of the phenolic hydroxyl group-containing acrylic rubber (a1) also reacts with a part of the fluororubber (b1) as a crosslinking point, the acrylic rubber layer (A) and the fluororubber layer (B) It is considered that the adhesive strength can be improved.

  Moreover, it is preferable to use a fluororubber (a2) as a crosslinking system of the phenolic hydroxyl group-containing acrylic rubber (a1), whereby an acrylic rubber obtained by crosslinking the acrylic rubber composition used for forming the acrylic rubber layer (A). It is considered that the heat resistance of the crosslinked product can also be improved. Therefore, the crosslinked acrylic rubber comprising the acrylic rubber composition containing the phenolic hydroxyl group-containing acrylic rubber (a1) and the fluororubber (a2) that can be preferably used has a high degree of heat resistance. The rubber laminate having the acrylic rubber layer (A) and the fluororubber layer (B) made of the composition also has a high degree of heat resistance.

  EXAMPLES Next, although an Example and a comparative example are shown and this invention is demonstrated concretely, these do not limit this invention at all. In the following description, “parts” means parts by weight and “%” means percent by weight, unless otherwise specified.

  In Examples and Comparative Examples, measurement of normal physical properties (tensile strength, elongation, hardness), measurement of heat aging resistance, peeling test of rubber laminate, and evaluation of adhesion by coextrusion method are performed as follows. It was.

[Measurement of normal physical properties (tensile strength, elongation, hardness) of crosslinked acrylic rubber]
The acrylic rubber compositions obtained in Examples and Comparative Examples are subjected to primary crosslinking (crosslinking conditions: 170 ° C., 20 minutes) using a hot press, and then subjected to secondary crosslinking (crosslinking conditions: 170 ° C., 4 hours). This gave a rubber cross-linked product. The obtained rubber cross-linked product was punched with a No. 3 type dumbbell to prepare a test piece. Next, normal physical properties were measured using this test piece. The hardness was measured using a durometer hardness tester (type A) according to JIS K6253 (2006). The tensile strength and elongation were measured according to JIS K6251 (2010).

[Measurement of heat aging resistance of crosslinked acrylic rubber]
About the rubber crosslinked material obtained by the measurement of the above-described normal physical properties, air heat aging property was measured as heat aging property. Air heat aging was performed under test conditions of 175 ° C. for 72 hours in accordance with JIS K6257 (2010), and the tensile strength, elongation, and hardness were measured. The evaluation of tensile strength and elongation was performed by determining the rate of change of the tensile strength and elongation obtained by measurement of air heat aging property with respect to the tensile strength and elongation obtained by measurement of the above normal physical properties, respectively. . In addition, the hardness was evaluated by determining the amount of change of the hardness obtained by measuring the air heat aging property with respect to the hardness obtained by measuring the above-mentioned normal physical properties.

[Peeling test of rubber laminate]
Using the rubber laminates obtained in the Examples and Comparative Examples, a cross-linking adhesion between the acrylic rubber layer (A) and the fluororubber layer (B) constituting the rubber laminate by performing a peel test according to JIS K6256 Was evaluated. Specifically, the obtained rubber laminate was punched into a strip shape having a width of 10 mm and a length of 100 mm, and both ends thereof were grasped by an air chuck of a tensile tester, and a 180 ° peel test at a speed of 50 mm / min. The load at the time of peeling was read with a load cell of a tensile tester, and the peel strength T _F (N / mm) was obtained.

In addition to the measurement of the peel strength, the state of the adhesive interface after the peel test was visually confirmed to evaluate the peel state. The condition of the adhesive interface is to check whether one rubber layer remains on the other rubber layer on the peeled surface after the peel test, and one rubber layer remains on the other rubber layer. (Ie, one rubber layer is completely destroyed), it is determined as “rubber destruction”, and one rubber layer is not left on the other rubber layer (ie, each rubber layer is broken). In the case where the rubber layer was peeled along the interface without being broken, it was determined as “interface peeling”.
The larger the value of the peel strength _TF, the more the rubber laminate is excellent in cross-linking adhesion when the state of the adhesive interface is “rubber failure”.

[Evaluation of adhesiveness by coextrusion (layer extrusion) method]
After the acrylic rubber composition and the fluororubber composition obtained in the examples and the comparative examples are formed into a laminated tube by a layer extrusion method, a rubber laminate is obtained by crosslinking under pressure and heat using a vulcanizing can. It was. It is determined whether or not the acrylic rubber layer (A) and the fluororubber layer (B) of the obtained rubber laminate are bonded. The results are shown in Table 1.

[Example 1]
[Polymerization of phenolic hydroxyl group-containing acrylic rubber]
In a polymerization reactor, 5 parts of dioctylsulfosuccinate sodium salt, an anionic emulsifier, dissolved in 1250 parts of deionized water, 148.2 parts of ethyl acrylate, 148.2 parts of butyl acrylate, p-hydroxybenzoic acid 3.6 parts of vinyl acid was added and emulsified by stirring. Next, after raising the temperature to 70 ° C. in a nitrogen stream, 10 parts of a 10% aqueous solution of ammonium persulfate was added to initiate polymerization. After the start of polymerization, the polymerization temperature was gradually raised to 80 ° C., and the polymerization reaction was continued in the range of 80 to 82 ° C. for 2 hours. The polymerization conversion was almost 100%. The obtained latex and salt (aqueous solution state) as a salting-out agent were mixed to obtain a crumb-like acrylic rubber. Thereafter, the crumb-like acrylic rubber was washed with water and dried to obtain acrylic rubber.

The composition of the acrylic rubber is ethyl acrylate unit: 49.4%, butyl acrylate unit: 49.4%, vinyl p-hydroxybenzoate unit: 1.2%, and Mooney viscosity (ML _{1 + 4} , 100 ° C) was 35.

得られたアクリルゴム組成物からアクリルゴム架橋物を得て、常態物性の測定及び耐熱老化性の測定を行った。 [Preparation of acrylic rubber composition]
Using a Banbury mixer, 100 parts of the above phenolic hydroxyl group-containing acrylic rubber, 60 parts of FEF carbon black (trade name “SEAST SO”, manufactured by Tokai Carbon Co., Ltd., filler), calcium silicate (AD850H200M, manufactured by Tomita Pharmaceutical Co., Ltd., acid received) 8 parts), 3 parts of an organosilicone compound (Strectol WS280, manufactured by S & S Japan Ltd., lubricant) and 1 part of an anti-aging agent were kneaded at 50 ° C. for 5 minutes. Next, the obtained kneaded product was transferred to an open roll at 50 ° C., 1.5 parts of fluororubber (Daiel G-101, manufactured by Daikin Industries, Ltd., cross-linking agent), tetrabutylammonium hydrogen sulfate (TBAHS, manufactured by Koei Chemical Co., Ltd.) , 0.25 part of a crosslinking accelerator) was kneaded to prepare an acrylic rubber composition. In addition, the compound represented by following formula (2) was used as an anti-aging agent.

An acrylic rubber cross-linked product was obtained from the obtained acrylic rubber composition, and normal physical properties and heat aging resistance were measured.

[Preparation of fluororubber composition]
Fluoro rubber containing a polyol cross-linking agent (trade name “VITON B-601C”, manufactured by DuPont Elastomer Co., Ltd., vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer rubber, and bisphenol AF as a polyol cross-linking agent 2.0 parts by weight) 100 parts MT carbon black (trade name “Thermax MT”, manufactured by Cancard Inc., filler), 20 parts MgO (trade name “Kyowa Mag 150”, manufactured by Kyowa Chemical Industry Co., Ltd.) , Acid acceptor) 3 parts, and Ca (OH) ₂ (trade name “Caldic # 1000”, manufactured by Omi Chemical Co., Ltd., acid acceptor) are added and kneaded with an open roll to obtain fluoro rubber. A composition was obtained.

[Manufacture of rubber laminate]
Each of the acrylic rubber composition and fluororubber composition obtained above is kneaded with an open roll, dispensed into a sheet with a uniform thickness of about 2 mm, and molded into a 6 cm × 10 cm square, A shaped molded body was obtained. Next, the obtained sheet-like molded bodies were bonded together, put into a mold having a length of 6 cm, a width of 10 cm, and a depth of 0.4 cm, and subjected to cross-linking adhesion at 170 ° C. for 20 minutes while pressing at a press pressure of 50 kg / cm ^2. Further, secondary rubber crosslinking (crosslinking condition: 170 ° C., 4 hours) was performed to prepare a rubber laminate. At this time, in order to perform the above-described peel test, the cellophane paper was previously sandwiched between the portions gripped by the air chuck during the peel test, thereby forming a portion where both sheets were not adhered.

[Comparative Example 1]
[Preparation of acrylic rubber composition]
Using a Banbury mixer, 100 parts of epoxy group-containing acrylic rubber (trade name "Nipol AR42W", manufactured by Nippon Zeon Co., Ltd.), 2 parts of stearic acid, FEF carbon black (trade name "Seast SO", manufactured by Tokai Carbon Co., Ltd.) Agent) 60 parts and anti-aging agent (trade name “NOCRACK CD”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 2 parts were kneaded at 50 ° C. for 5 minutes. Next, the obtained kneaded product was transferred to an open roll at 50 ° C., and 0.5 parts of tetrabutylphosphonium benzotriazolate (trade name “Zeonet PB”, manufactured by Nippon Zeon Co., Ltd., phosphonium salt), zinc dimethyldithiocarbamate ( Product name "Noxeller PZ", manufactured by Ouchi Shinsei Chemical Co., Ltd., 2.5 parts of dithiocarbamate metal salt, crosslinking agent), ferric dimethyldithiocarbamate (trade name "Noxeller TTFE", manufactured by Ouchi Shinsei Chemical Co., Ltd., cross-linking accelerator Agent) and 0.5 part of a sulfonamide derivative (trade name “Valcurrent E / C”, manufactured by LANXESS, scorch inhibitor) were added and kneaded to obtain an acrylic rubber composition. . An acrylic rubber crosslinked product was obtained using the obtained acrylic rubber composition, and normal physical properties and heat aging resistance were measured.
A rubber laminate was produced in the same manner as in Example 1 except that this acrylic rubber composition was used, and a peel test was performed on the obtained rubber laminate.

[Comparative Example 2]
An acrylic rubber composition was prepared in the same manner as in Comparative Example 1 except that tetrabutylphosphonium benzotriazolate was not added when preparing the acrylic rubber composition. An acrylic rubber cross-linked product was obtained from the obtained acrylic rubber composition, and normal physical properties and heat aging resistance were measured.
A rubber laminate was produced in the same manner as in Example 1 except that this acrylic rubber composition was used, and a peel test was performed on the obtained rubber laminate.

[Comparative Example 3]
Acrylic rubber composition obtained using a Banbury mixer in Comparative Example 1 (namely, epoxy group-containing acrylic rubber (trade name “Nipol AR42W”, 100 parts by Nippon Zeon Co., Ltd., 2 parts stearic acid, FEF carbon black (trade name) Acrylic rubber composition obtained by kneading 60 parts of “SEAST SO”, manufactured by Tokai Carbon Co., Ltd., and 2 parts of anti-aging agent (trade name “NOCRACK CD”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) On the other hand, 1.5 parts of ammonium benzoate (trade name “Barnock AB”, manufactured by Ouchi Shinsei Chemical Co., Ltd., cross-linking agent) was added to prepare an acrylic rubber composition. A crosslinked product was obtained, and normal physical properties and heat aging resistance were measured.

[Manufacture of rubber laminate]
The acrylic rubber composition obtained above and the fluororubber composition obtained in the same manner as in Example 1 were each kneaded with an open roll and dispensed into a sheet having a uniform thickness of about 2 mm. X A sheet-like molded body was obtained by molding into a 10 cm square. Next, a methyl ethyl ketone solution (10% by weight) of tetrabutylphosphonium benzotriazolate was applied to both the acrylic rubber composition and the fluororubber composition, and then air-dried for 30 minutes. The obtained sheet-like molded bodies were bonded together, put into a 6 cm long, 10 cm wide, and 0.4 cm deep mold, and subjected to cross-linking adhesion at 170 ° C. for 20 minutes while pressing with a press pressure of 50 kg / cm ^2. By performing secondary crosslinking (crosslinking conditions: 170 ° C., 4 hours), a rubber laminate was produced. At this time, in order to perform the above-described peel test, the cellophane paper was previously sandwiched between the portions gripped by the air chuck during the peel test, thereby forming a portion where both sheets were not adhered.

[Comparative Example 4]
Using a Banbury mixer, 100 parts of active chlorine group-containing acrylic rubber (trade name “Nipol AR72LS”, manufactured by Nippon Zeon Co., Ltd.), 2 parts of stearic acid, FEF carbon black (trade name “Seast SO”, manufactured by Tokai Carbon Co., Ltd., 60 parts of a filler and 2 parts of an anti-aging agent (trade name “NOCRACK CD”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) were kneaded at 50 ° C. for 5 minutes. Next, the obtained kneaded product was transferred to an open roll at 50 ° C., 0.3 parts of sulfur (crosslinking agent), 3 parts of sodium stearate (trade name “NS Soap”, manufactured by KAO, a crosslinking agent accelerator), An acrylic rubber composition was obtained by adding 0.5 parts of potassium stearate (trade name “Non-Sal SK-1”, manufactured by NOF Corporation, cross-linking agent accelerator) and kneading.
An acrylic rubber cross-linked product was obtained from the obtained acrylic rubber composition, and normal physical properties and heat aging resistance were measured.
A rubber laminate was produced in the same manner as in Comparative Example 3 except that this acrylic rubber composition was used, and a peel test was performed on the obtained rubber laminate.

  As shown in Table 1, an acrylic rubber layer (A) comprising an acrylic rubber composition containing an acrylic rubber (a1) having a phenolic hydroxyl group as a crosslinking point, a fluororubber (b1) and a polyol crosslinking agent (b2) The rubber laminate formed by cross-linking and adhering to the fluororubber layer (B) made of the fluororubber composition has high peel strength, and the state of the adhesive interface is “rubber failure”. It was excellent in properties. Moreover, the crosslinked acrylic rubber obtained from the acrylic rubber composition forming the acrylic rubber layer (A) is excellent in normal physical properties and heat resistance, and thus excellent in heat resistance of the rubber laminate (Example 1).

  On the other hand, when an acrylic rubber that does not contain a phenolic hydroxyl group is used as the acrylic rubber composition for forming the acrylic rubber layer (A) and a phosphonium salt is added as an adhesive component, the cross-linking adhesiveness of the rubber laminate The crosslinked acrylic rubber obtained from the acrylic rubber composition forming the acrylic rubber layer (A) is inferior in normal properties and heat resistance, and thus inferior in heat resistance of the rubber laminate (Comparative Example 1). .

  Moreover, as an acrylic rubber composition for forming the acrylic rubber layer (A), when an acrylic rubber not containing a phenolic hydroxyl group is used and no adhesive component is added, the rubber laminate is inferior in cross-linking adhesiveness. (Comparative example 2).

  Further, when an acrylic rubber not containing a phenolic hydroxyl group is used as an acrylic rubber composition for forming the acrylic rubber layer (A) and no adhesive component is added, the acrylic rubber layer (A) and the fluororubber layer When a phosphonium salt is applied as an adhesive component between (B), coextrusion cannot be performed. That is, the crosslinked acrylic rubber obtained from the acrylic rubber composition forming the acrylic rubber layer (A) is excellent in normal physical properties and heat resistance and has excellent adhesive crosslinkability, but the acrylic rubber layer (A) and the fluororubber layer. An adhesive for adhering to (B) is required, and further a process for applying this adhesive is required, so that it takes time to obtain a rubber laminate (Comparative Examples 3 and 4). .

Claims (3)

An acrylic rubber layer (A) comprising an acrylic rubber composition containing an acrylic rubber (a1) having a phenolic hydroxyl group as a crosslinking point;
A rubber laminate obtained by crosslinking and bonding a fluororubber layer (B) comprising a fluororubber composition containing a fluororubber (b1) and a polyol crosslinking agent (b2).   The rubber laminate according to claim 1, wherein the acrylic rubber composition further contains a fluororubber (a2).   A hose comprising the rubber laminate according to claim 1.