JP6179217B2 - Rubber laminate - Google Patents

Description

  The present invention relates to 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, and more specifically, an acrylic that constitutes the acrylic rubber layer. The present invention relates to a rubber laminate having good scorch stability of a rubber composition and excellent cross-linking adhesion after cross-linking adhesion.

  Gasohol, which is a mixture of gasoline and alcohol, is attracting attention as a fuel for automobiles due to the recent petroleum situation. Gasohol, on the other hand, has a stronger action to swell rubber than conventional gasoline, and acrylonitrile-butadiene rubber, which is generally used as oil-resistant rubber, causes rubber swelling and fuel permeation. There was a problem that it could not be used as a fuel hose for gasohol.

  On the other hand, fluorine rubber having gasohol resistance is used as a material for a fuel hose for gasohol. Fluoro rubber has excellent performance in heat resistance, oil resistance, solvent resistance, chemical resistance, etc. Especially among fluorinated rubbers, those of terpolymers have excellent gasohol resistance. Are known. However, on the other hand, since fluororubber has poor cold resistance and is expensive, when manufacturing a fuel hose, fluororubber is used as an inner thin layer, and the outer side has excellent cold resistance and weather resistance. A laminated structure using rubber, such as epichlorohydrin rubber, is employed.

  As a fuel hose having such a laminated structure, for example, in Patent Document 1, in a fuel hose obtained by heat-bonding a fluororubber layer and an epichlorohydrin rubber layer, in order to improve adhesion between these rubber layers A technique is disclosed in which a specific phosphonium salt is previously contained in the epichlorohydrin rubber constituting the epichlorohydrin rubber layer. However, the technique of Patent Document 1 has a problem that the epichlorohydrin rubber scorch becomes too fast by previously containing a specific phosphonium salt in the epichlorohydrin rubber, resulting in poor processability. .

  On the other hand, in Patent Document 2, in a fuel hose formed by heat-bonding a fluororubber layer and an epichlorohydrin rubber layer, a specific phosphonium salt is interposed between these rubber layers, A technique of laminating and heat-bonding is proposed. Although the technique of this patent document 2 can solve the problem of scorching, the rubber sheet which comprises a fluororubber layer is immersed in the solution containing a phosphonium salt, and, thereby, the process which makes a phosphonium salt adhere to the surface of a rubber sheet There is a problem that the manufacturing process becomes complicated.

JP-A-1-133734 JP-A-5-214118

  The present invention has been made in view of such a situation, and in 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, It is an object of the present invention to provide a rubber laminate capable of improving the cross-linking adhesiveness after cross-linking adhesion while improving the scorch stability of the acrylic rubber composition constituting the rubber layer.

  As a result of diligent research to achieve the above object, the present inventor, as an acrylic rubber composition for forming an acrylic rubber layer, an epoxy group-containing acrylic rubber with a specific amount of phosphonium salt and dithiocarbamic acid metal salt. By using the composition formed by blending, the scorch stability of the composition is good, and by cross-linking adhesion to the fluororubber layer made of the fluororubber composition, the cross-linking adhesiveness when the rubber laminate is obtained. The inventors have found that it can be made excellent, and have completed the present invention.

That is, according to the present invention, an acrylic rubber layer (A) comprising an acrylic rubber composition containing an epoxy group-containing acrylic rubber (a1), a phosphonium salt (a2), and a dithiocarbamic acid metal salt (a3), and a fluororubber The fluororubber layer (B) comprising the fluororubber composition containing (b1) is crosslinked and bonded, and the content of the phosphonium salt (a2) is 100 parts by weight of the epoxy group-containing acrylic rubber (a1). On the other hand, a rubber laminate is provided that is 1.5 to 4.5 parts by weight.
In the present invention, the fluororubber composition preferably further contains a polyol-based crosslinking agent (b2).

  Moreover, according to this invention, the hose which uses the said rubber laminated body is provided.

  According to the present invention, there is provided 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 the acrylic constituting the acrylic rubber layer. A rubber laminate having good scorch stability of the rubber composition and excellent cross-linking adhesion after cross-linking adhesion can be provided.

  The rubber laminate of the present invention comprises an acrylic rubber layer (A) comprising an acrylic rubber composition containing an epoxy group-containing acrylic rubber (a1), a phosphonium salt (a2), and a dithiocarbamic acid metal salt (a3), and a fluororubber. It is a rubber laminate formed by crosslinking and bonding a fluororubber layer (B) made of a fluororubber composition containing (b1). Moreover, in the rubber laminated body of this invention, the content rate of the said phosphonium salt (a2) is 1.5-4.5 weight part with respect to 100 weight part of said epoxy-group-containing acrylic rubbers (a1).

<Acrylic rubber composition>
First, the acrylic rubber composition for forming the acrylic rubber layer (A) of the rubber laminate of the present invention will be described. The acrylic rubber composition for forming the acrylic rubber layer (A) used in the present invention contains an epoxy group-containing acrylic rubber (a1), a phosphonium salt (a2), and a dithiocarbamic acid metal salt (a3).

<Epoxy group-containing acrylic rubber (a1)>
The epoxy group-containing acrylic rubber (a1) is a (meth) acrylic acid ester monomer as a main component [meaning an acrylic acid ester monomer and / or a methacrylic acid ester monomer. The same applies to methyl (meth) acrylate. ] A polymer containing a unit and a monomer unit having an epoxy group.

  Although it does not specifically limit as a (meth) acrylic acid ester monomer unit which forms the (meth) acrylic acid ester monomer unit as a main component of the epoxy-group-containing acrylic rubber (a1) used by this invention, For example, ( And (meth) acrylic acid alkyl ester monomers and (meth) acrylic acid alkoxyalkyl ester monomers.

  Although it does not specifically limit as a (meth) acrylic-acid alkylester monomer, The ester of C1-C8 alkanol and (meth) acrylic acid is preferable, Specifically, (meth) acrylic acid methyl, ( (Meth) ethyl acrylate, (meth) acrylic acid n-propyl, (meth) acrylic acid isopropyl, (meth) acrylic acid n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid n-hexyl, (meth) Examples include 2-ethylhexyl 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. These can be used alone or in combination of two or more.

  Although it does not specifically limit as a (meth) acrylic-acid alkoxyalkylester monomer, The ester of a C2-C8 alkoxyalkyl alcohol and (meth) acrylic acid is preferable, Specifically, (meth) acrylic acid Methoxymethyl, ethoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate , (Meth) acrylic acid 3-methoxypropyl, (meth) acrylic acid 4-methoxybutyl and the like. Among these, 2-ethoxyethyl (meth) acrylate and 2-methoxyethyl (meth) acrylate are preferable, and 2-ethoxyethyl acrylate and 2-methoxyethyl acrylate are particularly preferable. These can be used alone or in combination of two or more.

  The content of the (meth) acrylic acid ester monomer unit in the epoxy group-containing acrylic rubber (a1) used in the present invention is preferably 50 to 99.9% by weight, more preferably 60 to 99.5% by weight. More preferably, it is 70 to 99.5% by weight. When there is too little content of a (meth) acrylic acid ester monomer unit, there exists a possibility that the weather resistance of the rubber crosslinked material obtained, heat resistance, and oil resistance may fall.

  In the present invention, (meth) acrylic acid ester monomer units are 30 to 100% by weight of (meth) acrylic acid alkyl ester monomer units and (meth) acrylic acid alkoxyalkyl ester monomer units 70 to 70%. It is preferable to consist of 0% by weight.

  Although it does not specifically limit as a monomer which has an epoxy group which forms the monomer unit which has an epoxy group, For example, an epoxy group containing (meth) acrylic acid ester, an epoxy group containing ether, etc. are mentioned. The monomer unit having an epoxy group acts as a crosslinkable monomer unit in the epoxy group-containing acrylic rubber (a1).

Specific examples of the epoxy group-containing (meth) acrylic acid ester include glycidyl (meth) acrylate.
Specific examples of the epoxy group-containing ether include allyl glycidyl ether and vinyl glycidyl ether. Among these, glycidyl methacrylate and allyl glycidyl ether are preferable. These monomers having an epoxy group can be used alone or in combination of two or more.

  The content of the monomer unit having an epoxy group in the epoxy group-containing acrylic rubber (a1) used in the present invention is preferably 0.1 to 10% by weight, more preferably 0.5 to 7% by weight, Preferably it is 0.5 to 5 weight%. When there is too little content of the monomer unit which has an epoxy group, bridge | crosslinking will become inadequate and there exists a possibility that the intensity | strength of the acrylic rubber layer (A) after bridge | crosslinking may become inadequate. On the other hand, when there is too much content of the monomer unit which has an epoxy group, there exists a possibility that the elongation of the acrylic rubber layer (A) after bridge | crosslinking may fall.

  The epoxy group-containing acrylic rubber (a1) used in the present invention may have other crosslinkable monomer units as necessary in addition to the monomer units having an epoxy group. Examples of the crosslinkable monomer that forms other crosslinkable monomer units include α, β-ethylenically unsaturated carboxylic acid monomers; monomers having halogen atoms; monomers having hydroxyl groups; Etc.

  The crosslinkable monomers that form these other crosslinkable monomer units can be used alone or in combination of two or more. The content of the other crosslinkable monomer unit in the epoxy group-containing acrylic rubber (a1) used in the present invention can be appropriately determined within a range that does not impair the object and effect of the present invention.

  In addition to the above monomer units, the epoxy group-containing acrylic rubber (a1) used in the present invention contains a (meth) acrylic acid ester monomer or a monomer having an epoxy group, if necessary. You may have the unit of the other monomer copolymerizable with the crosslinkable monomer to contain.

  Other monomers that can be copolymerized are not particularly limited, and examples thereof include aromatic vinyl monomers, α, β-ethylenically unsaturated nitrile monomers, and monomers having two or more acryloyloxy groups. (Hereinafter, referred to as “polyfunctional acrylic monomer”), olefin monomers, vinyl ether compounds, and the like.

Specific examples of the aromatic vinyl monomer include styrene, α-methylstyrene, divinylbenzene, and the like.
Specific examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile and methacrylonitrile.
Specific examples of the polyfunctional acrylic monomer include ethylene glycol di (meth) acrylate and propylene glycol di (meth) acrylate.
Specific examples of the olefin monomer include ethylene, propylene, 1-butene, and 1-octene.
Specific examples of the vinyl ether compound include vinyl acetate, 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.

The other monomer which can be copolymerized can be used individually by 1 type or in combination of 2 or more types. The content of other monomer units in the epoxy group-containing acrylic rubber (a1) used in the present invention is preferably 49.9% by weight or less, more preferably 39.5% by weight or less, and even more preferably 29 .5% by weight or less.

  The epoxy 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 the polymerization, solid epoxy group-containing acrylic rubber (a1) is obtained through solidification and drying.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) (polymer Mooney) of the epoxy group-containing acrylic rubber (a1) used in the present invention produced in this way is preferably 10-80, more preferably 20-70, and further Preferably it is 25-60.

（上記一般式（１）中、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４は、それぞれ独立して、置換基を含んでいてもよい炭素数１〜２０の炭化水素基である。ただし、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４のうちの３個までは１〜３級アミノ基またはフルオロアルキル基でもよい。Ｒ^５は水素または炭素数１〜２０のアルキル基である。） <Phosphonium salt (a2)>
The phosphonium salt (a2) has an effect of improving the cross-linking adhesiveness between layers in the obtained rubber laminate, and the phosphonium salt (a2) is not particularly limited as long as it is a salt of a phosphorus compound. A compound represented by the following general formula (1) is preferable from the viewpoint that the cross-linking adhesiveness between layers in the obtained rubber laminate can be excellent.

(In the general formula (1), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a substituent. ^{1, R} 2, ^{R 3} and good .R ⁵ be up to three in primary to tertiary amino group or a fluoroalkyl group of ^{R 4} is hydrogen or an alkyl group having 1 to 20 carbon atoms.)

In the compound represented by the general formula (1), the hydrocarbon groups constituting R ¹ , R ² , R ³ and R ⁴ include alkyl groups such as methyl group, ethyl group, butyl group, ethylhexyl group and dodecyl group. A cycloalkyl group such as a cyclohexyl group; an aralkyl group such as a benzyl group or a methylbenzyl group; an aryl group such as a phenyl group, a naphthyl group, or a butylphenyl group; or a substituted aryl group.

In the compound represented by the general formula (1), examples of the primary to tertiary amino groups include a methylamino group, an ethylamino group, an anilino group, a dimethylamino group, and a diethylamino group. Includes a trifluoromethyl group, a tetrafluoropropyl group, an octafluoropentyl group, and the like. Further, R ⁵ is hydrogen or an alkyl group having 1 to 20 carbon atoms, and examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a butyl group, an ethylhexyl group, and a dodecyl group.

  Specific examples of the compound represented by the general formula (1) include tetrabutyl-phosphonium benzotriazolate, tetrabutyl-phosphonium tolyl triazolate, and hereinafter, only the two tetrabutyl-substitute parts are described ( That is, the description of -phosphonium benzotriazolate, -phosphonium tolyl triazolate is omitted), tetraoctyl-, methyltrioctyl-, butyltrioctyl-, phenyltributyl-, benzyltributyl-, benzyltricyclohexyl-, Benzyltrioctyl-, butyltriphenyl-, octyltriphenyl-, benzyltriphenyl-, tetraphenyl-, diphenyldi (diethylamino)-, phenylbenzyldi (dimethylamino)-, phenylbenzyldi (diethyladi Roh) -, trifluoromethylbenzyl -, tetrafluoropropyl trioctyl - and the like. Among these, tetrabutyl-phosphonium benzotriazolate is more preferable.

  The content ratio of the phosphonium salt (a2) in the acrylic rubber composition used in the present invention is 1.5 to 4.5 parts by weight with respect to 100 parts by weight of the epoxy group-containing acrylic rubber (a1), preferably The amount is 1.5 to 3.5 parts by weight, more preferably 1.5 to 2.5 parts by weight. When the content ratio of the phosphonium salt (a2) is within the above range, the effect of blending the phosphonium salt (a2), that is, the effect of improving the cross-linking adhesiveness between layers in the obtained rubber laminate can be obtained. Furthermore, since the scorch stability of the acrylic rubber composition is kept good, the processability is excellent. In particular, when the upper limit of the content ratio of the phosphonium salt (a2) is 3.5 parts by weight or less with respect to 100 parts by weight of the epoxy group-containing acrylic rubber (a1), the effect of scorch stability becomes remarkable.

<Dithiocarbamic acid metal salt (a3)>
The acrylic rubber composition used in the present invention contains a dithiocarbamic acid metal salt (a3) in addition to the epoxy group-containing acrylic rubber (a1) and the phosphonium salt (a2) described above. Dithiocarbamic acid metal salt (a3) is a compound that acts as a crosslinking agent and / or crosslinking accelerator. In the present invention, by using dithiocarbamic acid metal salt (a3) as a crosslinking agent and / or crosslinking accelerator, The scorch stability of the acrylic rubber composition can be kept good, and the cross-linking adhesiveness between layers in the resulting rubber laminate can be enhanced. That is, in the present invention, the phosphonium salt (a2) can be appropriately prevented by blending the metal salt of dithiocarbamate (a3) and appropriately preventing the disadvantage that the scorch stability is lowered due to the blending of the phosphonium salt (a2). The effect by compounding, that is, the cross-linking adhesiveness between layers in the obtained rubber laminate can be further enhanced.

  The dithiocarbamic acid metal salt (a3) is a metal salt of a dithiocarbamic acid compound (dithiocarbamic acid or a derivative thereof), specifically, zinc, copper, cadmium, lead of a dithiocarbamic acid compound (dithiocarbamic acid or a derivative thereof). , Metal salts such as bismuth, iron, cobalt, tellurium and selenium.

  Specific examples of the metal salt of dithiocarbamate (a3) include zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, lead dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, zinc di-n-hexyldithiocarbamate. , Zinc di-n-octyldithiocarbamate, zinc di-n-decyldithiocarbamate, zinc di-n-dodecyldithiocarbamate, zinc methylbenzyldithiocarbamate, zinc dibenzyldithiocarbamate, zinc methylcyclohexyldithiocarbamate, zinc dicyclohexyldithiocarbamate , Cadmium dimethyldithiocarbamate, cadmium diethyldithiocarbamate, bismuth dimethyldithiocarbamate, bidiethyldithiocarbamate Mass, ferric dimethyl dithiocarbamate can be mentioned ferric diethyldithiocarbamate, dimethyldithiocarbamate tellurium, tellurium diethyldithiocarbamate, dimethyldithiocarbamate selenium diethyldithiocarbamate selenium, and N- pentamethylene dithiocarbamate, zinc. Among these, a zinc salt of a dithiocarbamate compound is preferable and zinc dimethyldithiocarbamate is more preferable from the viewpoint that the effect of addition is high. The dithiocarbamic acid metal salt (a3) may be used alone or in combination of two or more. For example, a zinc salt of a dithiocarbamic acid compound and a dithiocarbamic acid compound These metal salts may be used in combination. In particular, when the zinc salt of the dithiocarbamic acid compound and the ferric salt of the dithiocarbamic acid compound are used in combination, the ferric salt of the dithiocarbamic acid compound acts as a crosslinking accelerator for the zinc salt of the dithiocarbamic acid compound. It is conceivable that the effect of the addition can be further enhanced.

  The content ratio of the dithiocarbamic acid metal salt (a3) in the acrylic rubber composition used in the present invention is preferably 0.1 to 10.0 parts by weight with respect to 100 parts by weight of the epoxy group-containing acrylic rubber (a1). Yes, more preferably 0.5 to 5.0 parts by weight, still more preferably 2.0 to 4.0 parts by weight. When the content ratio of the metal salt of dithiocarbamate (a3) is too low, crosslinking is insufficient, and the strength of the acrylic rubber layer (A) after crosslinking may be insufficient. On the other hand, if the content ratio is too high, the elongation of the acrylic rubber layer (A) after crosslinking may decrease. In particular, when the zinc salt of the dithiocarbamic acid compound and the ferric salt of the dithiocarbamic acid compound are used in combination, the content ratio of the zinc salt of the dithiocarbamic acid compound is 100 parts by weight of the epoxy group-containing acrylic rubber (a1). The content ratio of the ferric salt of the dithiocarbamic acid compound is preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the epoxy group-containing acrylic rubber (a1). 1.0 part by weight.

  In addition, in this invention, you may mix | blend a well-known scorch inhibitor from a viewpoint of improving the scorch stability of an acrylic rubber composition more. Examples of scorch inhibitors include organic acid scorch inhibitors such as phthalic anhydride, benzoic acid, salicylic acid and malic acid; nitroso compound scorch inhibitors such as N-nitrosodiphenylamine; thiophthalimide scorch such as N-cyclohexylthiophthalimide. Inhibitors; sulfonamide derivatives; 2-mercaptobenzimidazole; trichloromelamine; Of these, sulfonamide derivatives are preferred. The scorch inhibitor may be used alone or in combination of two or more. The blending amount of the scorch inhibitor in the acrylic rubber composition used in the present invention is preferably 0.1 to 10.0 parts by weight and more preferably 100 parts by weight of the epoxy group-containing acrylic rubber (a1). Is 0.1 to 3.0 parts by weight, more preferably 0.2 to 2.0 parts by weight.

<Other ingredients>
Moreover, in the acrylic rubber composition used in the present invention, in addition to the above components, a compounding agent usually used in the rubber processing field can be blended. Examples of such a compounding agent include reinforcing fillers such as carbon black and silica; non-reinforcing fillers such as calcium carbonate and clay; anti-aging agents; light stabilizers; plasticizers; processing aids; Adhesives; lubricants; flame retardants; antifungal agents; antistatic agents; coloring agents; silane coupling agents; 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. In addition, it is preferable to contain 30 weight part or less with respect to 100 weight part of epoxy-group-containing acrylic rubber (a1), and, as for the compounding quantity in the case of using a plasticizer, it is more preferable to contain 15 weight part or less. By making the compounding quantity of a plasticizer into the said range, the improvement effect of the crosslinking adhesiveness between layers in the rubber laminated body obtained can be improved more.

  The method for preparing the acrylic rubber composition used in the present invention is not particularly limited, and each component may be kneaded according to a conventional method. For example, phosphonium salt (a2) and dithiocarbamic acid metal salt (a3) are unstable to heat. After kneading the component excluding these components and the epoxy group-containing acrylic rubber (a1), heat-unstable components such as the phosphonium salt (a2) and the metal salt of dithiocarbamate (a3) are quickly added to the kneaded product. The desired composition can be obtained by mixing.

  As described above, since the acrylic rubber composition used in the present invention is a combination of the phosphonium salt (a2) and the dithiocarbamic acid metal salt (a3), the addition effect of the dithiocarbamic acid metal salt (a3) The problem that the scorch stability is lowered due to the blending of the phosphonium salt (a2) can be appropriately prevented, whereby the scorch stability of the resulting acrylic rubber composition can be kept good. . Moreover, the acrylic rubber composition used in the present invention is an effect obtained by compounding the phosphonium salt (a2) by using the phosphonium salt (a2) and the metal salt of dithiocarbamate (a3) in combination, that is, the resulting rubber. The effect of improving the cross-linking adhesiveness between layers in the laminate can be further enhanced.

<Fluorine rubber composition>
Next, the fluororubber composition for forming the fluororubber layer (B) of the rubber laminate of the present invention will be described. The fluororubber composition used in the present invention contains at least fluororubber (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.

  In the present invention, the fluororubber (b1) is a binary copolymer such as vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-perfluoromethyl vinyl ether copolymer. Terpolymers such as vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer; and terpolymers from the viewpoint of particularly excellent gasohol resistance. Rubber is particularly preferred.

  The fluororubber composition used in the present invention preferably contains a crosslinking agent. The crosslinking agent is not particularly limited, and conventionally known crosslinking agents such as a polyol-based crosslinking agent (b2), an organic peroxide-based crosslinking agent, and an amine-based crosslinking agent are used for crosslinking the fluororubber. be able to. In particular, the fluororubber composition used in the present invention further contains a polyol-based crosslinking agent (b2) as a crosslinking agent for crosslinking the fluororubber (b1) in addition to the fluororubber (b1). preferable. By blending the polyol-based crosslinking agent (b2), the fluororubber layer (B) made of the fluororubber composition was formed, and this was cross-linked and adhered to the acrylic rubber layer (A) made of the acrylic rubber composition described above. In this case, the cross-linking adhesiveness can be further improved.

  The polyol-based crosslinking agent (b2) is not particularly limited, but 2,2-bis (4-hydroxyphenyl) hexafluoropropane (bisphenol AF), 1,1-bis (4-hydroxyphenyl) methane, 1,1 Examples thereof include compounds having a phenolic OH group such as polyhydroxy aromatic compounds such as -bis (4-hydroxyphenyl) -1,1-dimethylmethane and p, p'-dihydroxybenzene. Among these, 2,2-bis (4-hydroxyphenyl) hexafluoropropane (bisphenol AF) is preferable. A polyol type crosslinking agent (b2) may be used individually by 1 type, or may use 2 or more types together.

  The content of the polyol-based crosslinking agent (b2) in the fluororubber composition used in the present invention is preferably 0.5 to 5.0 parts by weight with respect to 100 parts by weight of the fluororubber (b1). Preferably it is 0.7-4.0 weight part, More preferably, it is 1.0-3.0 weight part. If the content of the polyol-based crosslinking agent (b2) is too low, the crosslinking of the fluororubber (b1) becomes insufficient, and the strength of the crosslinked fluororubber layer (B) may be insufficient. On the other hand, if the content ratio is too high, the elongation of the fluororubber layer (B) after crosslinking may decrease.

  In addition to the above components, the fluororubber composition used in the present invention may contain a compounding agent usually used in the rubber processing field. Examples of such compounding agents include reinforcing fillers such as carbon black and silica; acid acceptors such as magnesium oxide; cross-linking accelerators; anti-aging agents; light stabilizers; plasticizers; processing aids; Adhesives; lubricants; flame retardants; antifungal agents; antistatic agents; coloring agents; silane coupling agents; 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 method for preparing the fluororubber composition used in the present invention is not particularly limited, and each component may be kneaded according to a conventional method. For example, the target composition is obtained by kneading fluororubber (b1) and each compounding agent. Can be obtained.

<Rubber laminate>
Next, the rubber laminate of the present invention will be described. 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, fluorine rubber 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.

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

  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 moreover, the cross-linking adhesiveness between the layers constituting the rubber laminate (cross-linked acrylic rubber layer (A) and fluororubber layer ( B) is excellent in cross-linking adhesiveness). Therefore, the rubber laminate of the present invention takes advantage of these characteristics, for example, O-rings, gaskets, packings, oil seals, bearing seals and the like in a wide range of transportation machines such as automobiles, general equipment, and electrical equipment. Sealing materials; oil tubes, fuel hoses, inlet hoses and other hoses; transmission belts, endless belts and other industrial belts; cushioning materials, vibration-proofing materials; wire covering materials; sheets; boots; dust covers; Useful as such. In particular, the rubber laminate of the present invention can be suitably used for hose applications.

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

[Mooney scorch test]
About the acrylic rubber composition, scorch time (t5 and t35) was measured under a measurement condition of 145 ° C. according to JIS K6300. It can be said that the longer the scorch time, the better the scorch stability.

[Normal properties (tensile strength, elongation, hardness)]
The acrylic rubber composition was placed in a mold having a length of 15 cm, a width of 15 cm, and a depth of 0.2 cm, and pressed at 160 ° C. for 30 minutes while being pressed at a press pressure of 10 MPa, to obtain a sheet-like rubber cross-linked product. The obtained sheet-like rubber cross-linked product was punched out with a No. 3 type dumbbell to prepare a test piece. Next, using this test piece, tensile strength and elongation were measured according to JIS K6251, and hardness was measured using a durometer hardness tester (type A) according to JIS K6253.

[Peel test]
Using the obtained rubber laminate, a peel test was performed according to JIS K6256 to evaluate the cross-linking adhesiveness between both layers constituting the rubber laminate. Specifically, the obtained rubber laminate was punched into a strip shape having a width of 25.4 mm and a length of 100 mm, and both ends thereof were gripped by an air chuck of a tensile tester, and at a speed of 50 mm / min, 180 °. A peel test was performed, 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 was evaluated by determining the area ratio of one rubber layer remaining on the other rubber layer on the peeled surface after the peel test as a percentage. That is, when the obtained area ratio (percentage) is α, it is represented by “R−α”. Specifically, “R-100” indicates that 100% of one rubber layer remained on the other rubber layer (that is, one rubber layer was completely destroyed). “R-0” means that one rubber layer does not remain on the other rubber layer (that is, each rubber layer was peeled along the interface without being destroyed). It is shown that. Furthermore, “R-50” indicates that 50% of one rubber layer remained on the other rubber layer.
The larger the value of the peel strength _{TF and} the larger the numerical value representing the state of the adhesive interface (that is, the value of α in “R-α”), the more the rubber laminate is excellent in cross-linking adhesion. To do.

[Example 1]
[Preparation of acrylic rubber composition]
Using a Banbury mixer, epoxy group-containing acrylic rubber (trade name “Nipol AR42W”, Nippon Zeon (a1)) 100 parts, stearic acid 1 part, ester wax (trade name “Greg G-8205”, large Nippon Ink Chemical Co., Ltd., lubricant 1 part, FEF carbon black (trade name “SEAST SO”, Tokai Carbon Co., filler) 70 parts, di (butoxyethoxyethyl) adipate (product name “Adeka Sizer RS-107” 10 parts of ADEKA, plasticizer) was added and kneaded at 50 ° C. for 5 minutes. Subsequently, the obtained kneaded product was transferred to an open roll at 50 ° C., and tetrabutylphosphonium benzotriazolate (trade name “Zeonet PB”, manufactured by Nippon Zeon Co., Ltd., phosphonium salt (a2)), zinc dimethyldithiocarbamate. (Product name “Noxeller PZ”, manufactured by Ouchi Shinsei Chemical Co., Ltd., dithiocarbamate metal salt (a3), cross-linking agent) 2.5 parts, ferric dimethyldithiocarbamate (Product name “Noxeller TTFE”, Ouchi Shinsei Chemical Company) And 0.5 parts of a dithiocarbamic acid metal salt (a3), a crosslinking accelerator) and 0.5 part of a sulfonamide derivative (trade name “Valcurrent E / C”, LANXESS, scorch inhibitor) Acrylic rubber composition was obtained by kneading.

[Preparation of fluororubber composition]
Fluoro rubber containing polyol-based crosslinking agent (b2) using an open roll (trade name “VITON B-601C”, manufactured by DuPont Elastomer Co., Ltd., vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer 100 parts of rubber and bisphenol AF as a polyol-based crosslinking agent (b2) in an amount of about 2.0% by weight), 20 parts of MT carbon black (trade name “Thermax MT”, manufactured by cancarb, a filler), 3 parts of MgO (trade name “Kyowa Mag 150”, manufactured by Kyowa Chemical Industry Co., Ltd., acid acceptor), and 6 parts of Ca (OH) ₂ (trade name “Caldic # 1000”, manufactured by Omi Chemical Co., Ltd., acid acceptor) The fluororubber composition was obtained by adding a part and knead | mixing at 50 degreeC.

[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 are 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 160 ° C. for 30 minutes while pressing with a press pressure of 50 kg / cm ² . Thus, 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.

  Then, using the acrylic rubber composition obtained above, Mooney scorch test and evaluation of normal properties were performed, and a peel test was performed using the rubber laminate. The results are shown in Table 1.

[Example 2]
When preparing the acrylic rubber composition, except that the amount of FEF carbon black was changed from 70 parts to 80 parts and the amount of di (butoxyethoxyethyl) adipate was changed from 10 parts to 20 parts, An acrylic rubber composition was produced in the same manner as in Example 1, and a rubber laminate was obtained in the same manner as in Example 1 and was similarly tested and evaluated. The results are shown in Table 1.

[Example 3]
An acrylic rubber composition was prepared in the same manner as in Example 1 except that the amount of tetrabutylphosphonium benzotriazolate was changed from 2 parts to 4 parts when preparing the acrylic rubber composition. A rubber laminate was obtained in the same manner as in Example 1, and was similarly tested and evaluated. The results are shown in Table 1.

[Comparative Example 1]
An acrylic rubber composition was prepared in the same manner as in Example 1 except that 2 parts of tetrabutylphosphonium benzotriazolate was not blended when preparing the acrylic rubber composition. Thus, a rubber laminate was obtained and similarly tested and evaluated. The results are shown in Table 1.

[Comparative Example 2]
An acrylic rubber composition was produced in the same manner as in Example 1 except that the amount of tetrabutylphosphonium benzotriazolate was changed from 2 parts to 1 part when preparing the acrylic rubber composition. A rubber laminate was obtained in the same manner as in Example 1, and was similarly tested and evaluated. The results are shown in Table 1.

[Comparative Example 3]
In preparing the acrylic rubber composition, 2.5 parts of zinc dimethyldithiocarbamate, 0.5 parts of ferric dimethyldithiocarbamate, and 0.5 parts of the sulfonamide derivative were not blended, and instead, An acrylic rubber composition was prepared in the same manner as in Example 1 except that 1.5 parts of ammonium benzoate (trade name “Barnock AB”, manufactured by Ouchi Shinsei Chemical Co., Ltd., cross-linking agent) was used. A rubber laminate was obtained in the same manner as in No. 1, and the test and evaluation were conducted in the same manner. The results are shown in Table 1.

[Comparative Example 4]
In preparing the acrylic rubber composition, 2.5 parts of zinc dimethyldithiocarbamate, 0.5 parts of ferric dimethyldithiocarbamate, and 0.5 parts of the sulfonamide derivative were not blended, and instead, An acrylic rubber composition was prepared in the same manner as in Example 2 except that 1.5 parts of ammonium benzoate (trade name “Barnock AB”, manufactured by Ouchi Shinsei Chemical Co., Ltd., crosslinking agent) was used. A rubber laminate was obtained in the same manner as in No. 2, and the test and evaluation were conducted in the same manner. The results are shown in Table 1.

[Comparative Example 5]
In preparing the acrylic rubber composition, 2.5 parts of zinc dimethyldithiocarbamate, 0.5 parts of ferric dimethyldithiocarbamate, and 0.5 parts of the sulfonamide derivative were not blended, and instead, Other than using 0.6 parts of isocyanuric acid (trade name “ZEONET A”, manufactured by Tokyo Materials Co., Ltd., cross-linking agent) and 1.3 parts of diphenylurea (trade name “ZEONET U”, manufactured by Tokyo Materials Co., Ltd., scorch inhibitor) Acrylic rubber composition was prepared in the same manner as in Example 1, and a rubber laminate was obtained in the same manner as in Example 1 and was similarly tested and evaluated. The results are shown in Table 1.

  From Table 1, the acrylic rubber composition containing the epoxy group-containing acrylic rubber (a1), phosphonium salt (a2), and dithiocarbamic acid metal salt (a3) has a long scorch time and good scorch stability. (Examples 1 to 3), in particular, in Examples 1 and 2, the effect of the scorch stability was significant compared to Example 3. Furthermore, the rubber laminate obtained by crosslinking and bonding the acrylic rubber layer (A) obtained using such an acrylic rubber composition and the fluororubber layer (B) made of the fluororubber composition has a peel strength. Further, the index “R-α” indicating the state of the adhesive interface was large, and the cross-linking adhesiveness was excellent (Examples 1 to 3).

On the other hand, when the acrylic rubber composition is prepared, when the phosphonium salt (a2) is not blended, or when the blending amount of the phosphonium salt (a2) is too small, the cross-linking adhesiveness when the rubber laminate is formed is inferior. (Comparative Examples 1 and 2).
Furthermore, when an acrylic rubber composition is prepared, a phosphonium salt (a2) is added when ammonium benzoate is used instead of the metal salt of dithiocarbamate (a3) as a crosslinking agent. However, it was inferior to the cross-linking adhesiveness in the case of a rubber laminate (Comparative Examples 3 and 4).
Moreover, when preparing an acrylic rubber composition, when isocyanuric acid is used instead of the dithiocarbamic acid metal salt (a3) as a crosslinking agent, the peel strength in the case of a rubber laminate is inferior. there were. Moreover, compared with Example 1 using the same amount of phosphonium salt (a2), the scorch time was short and the scorch stability was inferior (Comparative Example 5).

Claims (3)

An acrylic rubber layer (A) comprising an acrylic rubber composition containing an epoxy group-containing acrylic rubber (a1), a phosphonium salt (a2), and a metal salt of dithiocarbamate (a3); a fluororubber (b1) ; A cross-linking adhesion with the fluororubber layer (B) comprising the fluororubber composition containing the agent (b2) ,
The rubber laminate, wherein the content of the phosphonium salt (a2) is 1.5 to 4.5 parts by weight with respect to 100 parts by weight of the epoxy group-containing acrylic rubber (a1). The rubber laminate according to claim 1, wherein the phosphonium salt (a2) is a compound represented by the following general formula (1).

(In the above general formula (1), R ¹ , R ² , R ³ And R ⁴ Are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a substituent. However, R ¹ , R ² , R ³ And R ⁴ Up to three of them may be primary to tertiary amino groups or fluoroalkyl groups. R ⁵ Is hydrogen or an alkyl group having 1 to 20 carbon atoms. ) A hose comprising the rubber laminate according to claim 1.