JP2007230064A - Rubber laminate, its manufacturing method, and rubber hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber laminate which is excellent in oil resistance, gasoline impermeability, cold resistance, and mechanical properties and a rubber hose. <P>SOLUTION: The rubber laminates comprises first layer rubber (A) and second layer rubber (B). The first layer rubber (A) is composed of a polymer alloy comprising 40-90 wt.% of a nitrile rubber (A1) and 60-10 wt.% of an acrylic polymer (A2). The second layer rubber (B) is composed of a polymer alloy comprising 40-90 wt.% of a nitrile rubber (B1) and 60-10 wt.% of an ethylene-α-olefin copolymer rubber (B2). The acrylic polymer (A2) is a resin containing 35-99 wt.% of a (meth)acrylate monomer unit and 1-65 wt.% of an α, β-ethylenically unsaturated nitrile monomer unit. In the rubber hose, the first layer rubber (A) is made an inner layer and the second layer rubber (B) is made an outer layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rubber laminate and a rubber hose, and more particularly to a rubber laminate and a rubber hose which are excellent in oil resistance, gasoline permeation resistance, cold resistance, ozone resistance, and mechanical properties and are suitable as automobile parts.

  Nitrile rubber represented by acrylonitrile-butadiene rubber (NBR) is known as a rubber excellent in oil resistance. However, since nitrile rubber has insufficient weather resistance such as ozone resistance, so-called polyblend blended with vinyl chloride resin has been used for a long time to improve it. Such products are excellent in oil resistance and ozone resistance, but are not sufficiently cold resistant, and may cause environmental pollution by halogen when discarded.

In order to solve this problem, the present applicant previously heat-treated a polymer composition comprising 40 to 90% by weight of nitrile rubber and 60 to 10% by weight of a crosslinkable functional group-containing acrylic polymer in a specific temperature range. A rubber vulcanizate formed by blending a vulcanizing agent (Patent Document 1), 40 to 90% by weight of nitrile rubber, and 1 to 27% by weight of an α, β-ethylenically unsaturated nitrile monomer unit A polymer alloy (Patent Document 2) consisting of 60 to 10% by weight of an acrylic polymer is proposed. However, although these are effective in use in cold regions, further improvements in cold resistance, gasoline permeation resistance and ozone resistance have been demanded.
Patent Document 3 has proposed a fuel hose comprising a laminate of an acrylic polymer layer containing an acrylonitrile monomer unit and a fluororesin layer excellent in gasoline permeability resistance. Interlayer adhesion strength (mechanical properties) was not sufficient.

Republished patent WO2003-046073 JP 2004-91506 A JP 2004-150457 A

  An object of the present invention is to provide a rubber laminate and a rubber hose which are excellent in mechanical properties (such as adhesive strength) in addition to being excellent in oil resistance, gasoline permeation resistance, cold resistance and ozone resistance.

  As a result of earnest research to achieve the above-mentioned object, the inventors of the present invention are composed of a first layer rubber and a second layer rubber each made of a specific polymer alloy, and a rubber laminate having high adhesion strength between both layers. It has been found that the above problems can be solved, and the present invention has been completed based on this finding.

Thus, according to the present invention, a rubber laminate comprising the first layer rubber (A) and the second layer rubber (B), wherein the first layer rubber (A) is 40 to 90% by weight of the nitrile rubber (A1) and The second layer rubber (B) is composed of 40 to 90% by weight of nitrile rubber (B1) and ethylene-α-olefin copolymer rubber (B2). ) Comprising a polymer alloy composed of 60 to 10% by weight, wherein the acrylic polymer (A2) comprises 35 to 99% by weight of (meth) acrylic acid ester monomer units, and A rubber laminate is provided which is a resin containing 65 to 1% by weight of a saturated nitrile monomer unit. Preferably, the embrittlement temperature of the second layer rubber (B) is −30 ° C. or lower.
According to another aspect of the present invention, the vulcanization time start point t _{B10 of} the second layer rubber (B) is between the vulcanization time start point t _A10 and the end point t _{A90 of} the first layer rubber (A). A method for producing these rubber laminates is provided, characterized in that an end point t _B90 is present.
According to another aspect of the present invention, there is provided a rubber hose comprising these rubber laminates having the first layer rubber (A) as an inner layer and the second layer rubber (B) as an outer layer, and preferably the outer layer comprises: Even if it is kept for 72 hours in a 30% stretched state in an environment with an ozone concentration of 50 pphm and a temperature of 40 ° C., it has ozone resistance so that no cracks are visible.

  According to the present invention, there are provided a rubber laminate and a rubber hose which are excellent in mechanical properties (adhesive strength) in addition to being excellent in oil resistance, gasoline permeation resistance, cold resistance and ozone resistance.

The rubber laminate of the present invention is a rubber laminate comprising a first layer rubber (A) and a second layer rubber (B), wherein the first layer rubber (A) is 40 to 90% by weight of nitrile rubber (A1) and The second layer rubber (B) is composed of 40 to 90% by weight of nitrile rubber (B1) and ethylene-α-olefin copolymer rubber (B2). ) Comprising a polymer alloy composed of 60 to 10% by weight, wherein the acrylic polymer (A2) comprises 35 to 99% by weight of (meth) acrylic acid ester monomer units, and It is a resin containing 65 to 1% by weight of a saturated nitrile monomer unit.
The rubber hose of the present invention comprises a rubber laminate having the first layer rubber (A) as an inner layer and the second layer rubber (B) as an outer layer.

  Hereinafter, for the first layer rubber (A) and then the second layer rubber (B), the rubber of each component, the rubber composition obtained by mixing them and the vulcanizable rubber composition will be described in order, A rubber laminate and a rubber hose manufactured using the vulcanizable rubber composition of both layers will be described.

  Nitrile rubber (A1) which is the first component of the first layer rubber (A) is composed of an α, β-ethylenically unsaturated nitrile monomer and other monomers copolymerizable with the monomer. A rubber obtained by copolymerizing (I) and hydrogenating a carbon-carbon unsaturated bond of the main chain as necessary.

  Examples of the α, β-ethylenically unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. Of these, acrylonitrile is preferable. The content of the α, β-ethylenically unsaturated nitrile monomer unit in the nitrile rubber (A1) is preferably 30 to 80% by weight, more preferably 35 to 60% by weight. If the content of the α, β-ethylenically unsaturated nitrile monomer unit is too small, the first layer rubber (A) may be inferior in oil resistance, in particular, alcohol-resistant gasoline resistance. May be inferior.

  Other monomers (I) copolymerizable with α, β-ethylenically unsaturated nitrile monomers include conjugated diene monomers, non-conjugated diene monomers, α-olefin monomers, and aromatics. Vinyl monomer, fluorine-containing vinyl monomer, α, β-ethylenically unsaturated monocarboxylic acid monomer, α, β-ethylenically unsaturated polyvalent carboxylic acid monomer or anhydride thereof, α, β -Ethylenically unsaturated carboxylic acid ester monomer, copolymerizable anti-aging agent and the like. Among these, since the nitrile rubber (A1) has rubber elasticity, a conjugated diene monomer or an α-olefin is preferable, and a conjugated diene monomer is particularly preferable.

Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and the like. Of these, 1,3-butadiene is preferable.
The non-conjugated diene monomer preferably has 5 to 12 carbon atoms, and examples thereof include 1,4-pentadiene, 1,4-hexadiene, vinyl norbornene, and dicyclopentadiene.
The α-olefin monomer preferably has 2 to 12 carbon atoms, and examples thereof include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene.
Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyl pyridine and the like.
Examples of the fluorine-containing vinyl monomer include fluoroethyl vinyl ether, fluoropropyl vinyl ether, o-trifluoromethylstyrene, vinyl pentafluorobenzoate, difluoroethylene, and tetrafluoroethylene.
Examples of the α, β-ethylenically unsaturated monocarboxylic acid monomer include acrylic acid and methacrylic acid.
Examples of the α, β-ethylenically unsaturated polyvalent carboxylic acid monomer include itaconic acid, fumaric acid and maleic acid.
Examples of the anhydride of the α, β-ethylenically unsaturated polyvalent carboxylic acid monomer include itaconic anhydride and maleic anhydride.

  The α, β-ethylenically unsaturated carboxylic acid ester monomer has an alkyl group having 1 to 18 carbon atoms such as methyl acrylate, ethyl acrylate, n-dodecyl acrylate, methyl methacrylate, and ethyl methacrylate. (Meth) acrylic acid ester; (meth) acrylic acid ester having an alkoxyalkyl group having 2 to 12 carbon atoms such as methoxymethyl acrylate and methoxyethyl methacrylate; α-cyanoethyl acrylate, β-cyanoethyl acrylate, methacrylic acid (Meth) acrylic acid ester having a cyanoalkyl group having 2 to 12 carbon atoms such as cyanobutyl; hydroxy having 1 to 12 carbon atoms such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 2-hydroxyethyl methacrylate (Meth) actyl having an alkyl group Α, β-ethylenic dicarboxylic acid monoalkyl esters such as monoethyl maleate and mono-n-butyl itaconate; α, β-ethylene such as dimethyl maleate, dimethyl fumarate, dimethyl itaconate and diethyl itaconate Dialkyl acid dialkyl esters; amino group-containing α, β-ethylenically unsaturated carboxylic acid esters such as dimethylaminomethyl acrylate and diethylaminoethyl acrylate; fluoroalkyl groups such as trifluoroethyl acrylate and tetrafluoropropyl methacrylate (Meth) acrylic acid ester; fluorine-substituted benzyl (meth) acrylic acid ester such as fluorobenzyl acrylate and fluorobenzyl methacrylate;

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

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the nitrile rubber (A1) is preferably 10 to 300, more preferably 20 to 250, and particularly preferably 30 to 200. If the Mooney viscosity is too small, the mechanical strength of the first layer rubber (A) may be reduced. On the other hand, if the Mooney viscosity is too large, the workability may be reduced.

  The method for producing the nitrile rubber (A1) is not particularly limited, and the monomer may be polymerized according to a known method, and an emulsion polymerization method or a solution polymerization method is preferably employed.

  The acrylic polymer (A2) which is the second component of the first layer rubber (A) is a (meth) acrylic acid ester monomer unit (“acrylic acid ester monomer unit and / or methacrylic acid ester single monomer” Meaning “body unit”.) The content of the (meth) acrylic acid ester monomer unit in the acrylic polymer (A2) is 35 to 99% by weight, preferably 40 to 90% by weight, and more preferably 50 to 85% by weight.

  Furthermore, the acrylic polymer (A2) contains 65 to 1% by weight, preferably 60 to 10% by weight or less, more preferably 50 to 15% by weight, of an α, β-ethylenically unsaturated nitrile monomer unit. By containing the α, β-ethylenically unsaturated nitrile monomer unit in the above range, the oil resistance, particularly the alcohol-mixed gasoline resistance is improved without reducing the ozone resistance of the first layer rubber (A). be able to. If the content of the α, β-ethylenically unsaturated nitrile monomer unit is too small, the alcohol-resistant gasoline resistance is lowered, and if it is too much, the ozone resistance tends to be lowered.

  Examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, ( T-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, etc. It is done.

  Examples of the α, β-ethylenically unsaturated nitrile monomer include the same monomers as those exemplified as the α, β-ethylenically unsaturated nitrile monomer in the nitrile rubber (A1). Of these, (meth) acrylonitrile is preferable.

The acrylic polymer (A2) contains units of other monomer (II) copolymerizable with the above α, β-ethylenically unsaturated nitrile monomer or (meth) acrylic acid ester monomer. You may do it. The content of other monomer (II) units is usually 50% by weight or less, preferably 20% by weight or less, and particularly preferably 10% by weight or less.
Other monomers (II) are particularly those that can be copolymerized with one or both of acrylic acid ester and methacrylic acid ester, or can be copolymerized with an α, β-ethylenically unsaturated nitrile monomer. It is not limited. Such monomers include aromatic vinyl monomers, vinyl ester monomers, vinyl ether monomers, α, β-ethylenically unsaturated monocarboxylic acid monomers, α, β-ethylenically unsaturated monomers. Examples thereof include polyvalent carboxylic acid monomers and anhydrides thereof. Examples of the vinyl ester monomer include vinyl acetate and vinyl propionate. Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, and hydroxybutyl vinyl ether. Examples of the aromatic vinyl monomer, the α, β-ethylenically unsaturated monocarboxylic acid monomer, the α, β-ethylenically unsaturated polyvalent carboxylic acid, and the anhydride thereof include other nitrile rubbers (A1). Examples thereof are the same as those exemplified as the monomer (I).

  The weight average molecular weight of the acrylic polymer (A2) (hereinafter sometimes referred to as “Mw”) is not particularly limited, but is preferably a polystyrene equivalent value in gel permeation chromatography (GPC), preferably 50,000. To 4,000,000, more preferably 100,000 to 2,000,000, and particularly preferably 200,000 to 1,500,000. If the Mw is too small, the ozone resistance of the first layer rubber (A) may be reduced. Conversely, if the Mw is too high, the moldability may be inferior.

  The acrylic polymer (A2) preferably has a glass transition temperature (Tg) or a melting temperature (Tm), whichever is higher, 50 to 250 ° C., more preferably 70 to 230 ° C. Depending on the structure of the acrylic polymer, there is a case where Tg is present but Tm is not present. In this case, Tg is regarded as Tt. If Tt is too low or too high, the ozone resistance of the first layer rubber (A) may be lowered.

Although the manufacturing method of an acrylic polymer (A2) is not specifically limited, It is preferable to obtain in a particle state by emulsion polymerization, suspension polymerization, etc. In emulsion polymerization and suspension polymerization, seed polymerization may be performed.
The acrylic polymer mass obtained by bulk polymerization is pulverized by a pulverizer such as a jet airflow pulverizer, a mechanical collision pulverizer, a roll mill, a hammer mill, an impeller breaker, etc. The particle diameter of the acrylic polymer can also be adjusted by introducing into a classification device such as a sieve classification device and classification.

  The average particle size of the acrylic polymer (A2) is not particularly limited, but is preferably 10 μm or less, more preferably 2 μm or less. If the average particle size is too large, the ozone resistance of the first layer rubber (A) tends to decrease. The average particle diameter of the acrylic polymer (A2) can be controlled by polymerization conditions.

A composition (hereinafter referred to as “the first layer rubber (A)” by adding a vulcanizing agent and vulcanizing.
Abbreviated as “rubber (A) composition”. ), The content of the nitrile rubber (A1) with respect to the total amount of the nitrile rubber (A1) and the acrylic polymer (A2) is 40 to 90% by weight, preferably 50 to 80% by weight. Moreover, content of an acrylic polymer (A2) is 60 to 10 weight%, Preferably it is 50 to 20 weight%. If the content of the nitrile rubber (A1) is too small and the content of the acrylic polymer (A2) is too large, the elasticity of the first layer rubber (A) may be lowered. Conversely, the nitrile rubber (A1) When there is too much content of and there is too little content of an acrylic polymer (A2), ozone resistance may fall.

  In addition to the nitrile rubber (A1) and the acrylic polymer (A2), the rubber (A) composition may contain other rubbers and resins as long as the effects of the present invention are not substantially impaired. The content of other rubber or resin 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 total amount of the rubber (A) composition. When there is too much content of other rubber etc., there exists a possibility that the gasoline permeability resistance, cold resistance, and ozone resistance of a 1st layer rubber (A) may fall.

  The rubber (A) composition has a compounding agent used for general rubber processing, for example, a reinforcing agent such as carbon black and silica; Fillers such as magnesium carbonate, clay, kaolin clay, talc, fine talc, mica, aluminum hydroxide, magnesium hydroxide, silicic acid, magnesium silicate, aluminum silicate, calcium silicate; α, β-unsaturated carboxylic Acid metal salts; pigments; anti-aging agents and the like may be included.

  The rubber (A) composition is prepared by mixing the above compounding agent blended as necessary with a polymer alloy composed of the nitrile rubber (A1) and the acrylic polymer (A2), for example, a mixer such as a roll or a Banbury mixer. It can prepare by the dry blend method etc. which mix by heating using. Moreover, you may prepare using the latex coprecipitation method which mixes a nitrile rubber (A1) and an acrylic polymer (A2) in a latex state, and solidifies.

  A vulcanizing agent can be blended with the rubber (A) composition to obtain a vulcanizable rubber composition (hereinafter abbreviated as “vulcanizable rubber (A) composition”). Examples of the vulcanizing agent include sulfur vulcanizing agents, organic peroxides, polyamine vulcanizing agents and the like.

  Examples of the sulfur-based vulcanizing agent include sulfur such as powdered sulfur and precipitated sulfur; and organic sulfur compounds such as 4,4'-dithiomorpholine, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and polymer polysulfide.

  Examples of the organic peroxide include dialkyl peroxides, diacyl peroxides, and peroxyesters. Dialkyl peroxides include dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne, and 2,5-dimethyl-2. , 5-di (t-butylperoxy) hexane, 1,3-bis (t-butylperoxyisopropyl) benzene, and the like. Examples of diacyl peroxides include benzoyl peroxide and isobutyryl peroxide. Examples of peroxyesters include 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyisopropyl carbonate, and the like.

The polyamine vulcanizing agent is not particularly limited as long as it is a compound having two or more amino groups, but a plurality of hydrogens of aliphatic hydrocarbons and aromatic hydrocarbons are represented by amino groups or hydrazide structures, that is, —CONHNH ₂ . Those substituted with the above structure are preferred. Examples of the polyamine vulcanizing agent include aliphatic polyvalent amines, aromatic polyvalent amines, and compounds having two or more hydrazide structures. Examples of the aliphatic polyvalent amines include hexamethylene diamine, hexamethylene diamine carbamate, tetramethylene pentamine, hexamethylene diamine-cinnamaldehyde adduct, hexamethylene diamine-dibenzoate salt, and the like. Examples of aromatic polyamines include 4,4′-methylenedianiline, 4,4′-oxydiphenylamine, m-phenylenediamine, p-phenylenediamine, 4,4′-methylenebis (o-chloroaniline), and the like. Can be mentioned. Examples of the compound having two or more hydrazide structures include isophthalic acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide.

  Although the compounding quantity of a vulcanizing agent changes with kinds of vulcanizing agent, Preferably it is 0.1-10 weight part with respect to 100 weight part of rubber | gum (A) compositions, More preferably, it is 0.3-7 weight part. Particularly preferred is 0.5 to 5 parts by weight. If the amount of the vulcanizing agent used is too small, the compression set of the first layer rubber (A) may increase, and conversely if too large, the bending fatigue resistance may be reduced.

  When using a sulfur-based vulcanizing agent, a vulcanization accelerator is usually used in combination. Examples of the vulcanization accelerator include zinc white, sulfenamide vulcanization accelerator, guanidine vulcanization accelerator, thiazole vulcanization accelerator, thiuram vulcanization accelerator, and dithioate vulcanization accelerator. Can be mentioned. The amount of the vulcanization accelerator used is not particularly limited, and may be determined according to the use of the vulcanizate, the required performance, the type of sulfur vulcanizing agent, the type of vulcanizing accelerator, and the like.

  When using an organic peroxide, a vulcanization aid is usually used in combination. Examples of the vulcanization aid include triallyl cyanurate, trimethylolpropane trimethacrylate, N, N′-m-phenylenebismaleimide and the like. These may be dispersed in clay, calcium carbonate, silica or the like to improve processability. The amount of the vulcanization aid used is not particularly limited, and may be determined according to the use of the vulcanizate, the required performance, the type of vulcanization agent, the type of vulcanization aid, and the like.

  The preparation method of the vulcanizable rubber (A) composition is not particularly limited, and may be performed by a known method of blending a vulcanizing agent with the rubber. However, the vulcanizing agent is preferably blended by a method in which shearing heat generation does not easily occur so that vulcanization does not proceed during mixing. For example, it is preferable that the components (rubber (A) composition) excluding the vulcanizing agent are mixed with a Banbury mixer, and then the vulcanizing agent is blended with a roll and finally mixed.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the vulcanizable rubber (A) composition is preferably 10 to 100, more preferably 15 to 70. If the Mooney viscosity is too low or too high, the processability of the vulcanizable rubber (A) composition may be lowered.

  The nitrile rubber (B1), which is the first component of the second layer rubber (B), is composed of an α, β-ethylenically unsaturated nitrile monomer and other monomers copolymerizable with the monomer. A rubber obtained by copolymerizing (III) and hydrogenating a carbon-carbon unsaturated bond in the main chain as necessary.

  The content of the α, β-ethylenically unsaturated nitrile monomer unit in the nitrile rubber (B1) is preferably 25 to 60% by weight, more preferably 28 to 50% by weight, particularly preferably 33 to 45% by weight. It is. If the content of the α, β-ethylenically unsaturated nitrile monomer unit is too small, the oil resistance of the second layer rubber (B) may be lowered, and conversely if too much, the cold resistance may be lowered. There is.

  As the α, β-ethylenically unsaturated nitrile monomer and the other monomer (III) constituting the nitrile rubber (B1), α, β- mentioned as the constituent monomer of the nitrile rubber (A1) Examples thereof include those similar to the ethylenically unsaturated nitrile monomer and other monomer (I). As the other monomer (III), a conjugated diene monomer or an α-olefin monomer is preferable because the nitrile rubber (B1) has rubber elasticity, a conjugated diene monomer is more preferable, and 1,3- Butadiene is more preferred.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the nitrile rubber (B1) is preferably 10 to 300, more preferably 20 to 250, and particularly preferably 30 to 200. If the Mooney viscosity of the nitrile rubber (B1) is too small, the mechanical strength of the second layer rubber (B) may be reduced. Conversely, if it is too large, the processability of the second layer rubber (B) may be reduced. There is sex.
Moreover, the manufacturing method of nitrile rubber (B1) is not specifically limited, What is necessary is just to copolymerize by a well-known method.

  The α-olefin monomer that forms the ethylene-α-olefin copolymer rubber (B2), which is the second component of the second layer rubber (B), is preferably one having 3 to 20 carbon atoms, Examples include propene, isobutylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

  The content of the α-olefin monomer unit in the ethylene-α-olefin copolymer rubber (B2) is preferably 1 to 50% by weight, more preferably 3 to 40% by weight, particularly preferably 5 to 30% by weight. is there. If the content of the α-olefin monomer unit is too small, the second layer rubber (B) may be inferior in cold resistance, and conversely if it is too large, the mechanical strength may be inferior.

  The ethylene-α-olefin copolymer rubber (B2) is obtained by further copolymerizing ethylene and another monomer (IV) copolymerizable with ethylene and α-olefin within a range not impairing the effects of the present invention. Also good. Other monomers (IV) include aromatic vinyl monomers such as styrene and alkyl-substituted styrene; diene monomers such as butadiene, 1,4-hexadiene and dicyclopentadiene; cyclopentene, cyclohexene, cyclooctene and the like And cycloolefin monomers.

  The number average molecular weight of the ethylene-α-olefin copolymer rubber (B2) (hereinafter sometimes referred to as “Mn”) is a polystyrene equivalent value in gel permeation chromatography, preferably 50,000 to 500. , 000, more preferably 60,000 to 300,000, particularly preferably 70,000 to 200,000. If Mn is too small, the mechanical strength of the second layer rubber (B) may be lowered. Conversely, if Mn is too large, the workability of the second layer rubber (B) may be lowered.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the ethylene-α-olefin copolymer rubber (B2) is preferably 10 to 300, more preferably 20 to 250, and particularly preferably 30 to 200. If the Mooney viscosity is too small, the mechanical strength of the second layer rubber (B) may be reduced. Conversely, if the Mooney viscosity is too large, the processability of the second layer rubber (B) may be deteriorated.

  The production method of the ethylene-α-olefin copolymer rubber (B2) is not particularly limited, and may be copolymerized by a known method, and usually a solution polymerization method is used.

  In the composition (hereinafter abbreviated as “rubber (B) composition”) which becomes the second layer rubber (B) by adding a vulcanizing agent and vulcanizing, nitrile rubber (B1) and ethylene-α- The content of the nitrile rubber (B1) with respect to the total amount of the olefin copolymer rubber (B2) is 40 to 90% by weight, preferably 45 to 80% by weight, and more preferably 50 to 75% by weight. Moreover, content of ethylene-alpha-olefin copolymer rubber (B2) is 60 to 10 weight%, Preferably it is 55 to 20 weight%, More preferably, it is 50 to 25 weight%. If the content of the nitrile rubber (B1) is too small and the content of the ethylene-α-olefin copolymer rubber (B2) is too large, the oil resistance of the second layer rubber (B) may be lowered. If the content of the nitrile rubber (B1) is too high and the content of the ethylene-α-olefin copolymer rubber (B2) is too low, the ozone resistance of the second layer rubber (B) may be lowered.

  In addition to the nitrile rubber (B1) and the ethylene-α-olefin copolymer rubber (B2), the rubber (B) composition may contain other rubbers and resins as long as the effects of the present invention are not impaired. The content of other rubber or resin 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 total amount of the rubber (B) composition. When there is too much content of other rubbers etc., there is a possibility that the gasoline permeation resistance, cold resistance or ozone resistance of the second layer rubber (B) may be lowered.

  The rubber (B) composition can contain the same compounding agent as in the rubber (A) composition as long as the effects of the present invention are not impaired. The rubber (B) composition is prepared by using the above-mentioned compounding agent blended as necessary with a polymer alloy composed of the nitrile rubber (B1) and the ethylene-α-olefin copolymer rubber (B2). The method can be performed in the same manner as the rubber (A) composition. In particular, it is preferable to add silica as a reinforcing agent because the adhesive strength between two layers by vulcanization adhesion of a rubber laminate is improved. The amount of silica is preferably 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the rubber (B) composition.

  A vulcanizing agent can be blended with the rubber (B) composition to obtain a vulcanizable rubber composition (hereinafter abbreviated as “vulcanizable rubber (B) composition”). Examples of the vulcanizing agent include the same sulfur-based vulcanizing agent, organic peroxide, polyamine-based vulcanizing agent and the like as the vulcanizing agent of the vulcanizable rubber (A) composition, which can be used in the same manner. .

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the vulcanizable rubber (B) composition is preferably 10 to 100, more preferably 15 to 70. If the Mooney viscosity is too low or too high, the processability of the vulcanizable rubber (B) composition may be lowered.

  The method for producing the rubber laminate of the present invention obtained by laminating the first layer rubber (A) and the second layer rubber (B) is not limited. For example, first, the vulcanizable rubber (A) composition And the vulcanizable rubber (B) composition by a known method such as press molding, roll molding, extrusion molding, etc., each having a thickness of preferably 0.1 to 5 mm, more preferably 0.5 to 2 mm and an arbitrary area. The sheet is molded in an unvulcanized state. Next, both sheets are superposed and vulcanized and bonded using a hot press or a vulcanizing can.

  In order to produce a rubber hose comprising a rubber laminate having the first layer rubber (A) as the inner layer and the second layer rubber (B) as the outer layer, the vulcanizable rubber (A) composition which is usually the inner layer Then, the vulcanizable rubber (B) composition as the outer layer is supplied to a two-layer extruder and molded by a two-layer extrusion method to form an unvulcanized laminated tube, and then vulcanized using a vulcanizer can The method to make is taken.

In producing the rubber laminate of the present invention by laminating the vulcanizable rubber (A) composition and the vulcanizable rubber (B) composition, the torsional vibration disk vulcanization tester (ODR) is used. The measured torque during vulcanization of the vulcanizable rubber (A) composition and the vulcanizable rubber (B) composition preferably satisfies the following relationship. That is, the time until the torque during vulcanization of the vulcanizable rubber (A) composition reaches 10% of the maximum torque (referred to as “the starting point of the vulcanization time of the first layer rubber (A)”) is t. _A10 , the time until the torque reaches 90% of the maximum torque (referred to as “end point of vulcanization time of the first layer rubber (A))” is _designated as t _A90, and thereafter the vulcanizable rubber (B) in the same manner as described above. The time required to reach 10% of the maximum torque during vulcanization of the composition (referred to as the “starting point of the vulcanization time of the second layer rubber (B)”) is t _B10 , the time required to reach 90% (“No. When t _B90 is referred to as “the end point of the vulcanization time of the two-layer rubber (B)”, t _B10 or t _B90 is preferably present between t _A10 and t _A90 . Adopting conditions under which such a relationship is found between the vulcanization rates of both layers improves the adhesive strength between the two layers.
The vulcanization speed of both layers can be adjusted by adjusting the type and amount of the vulcanizing agent, vulcanization accelerator, vulcanization aid or other compounding agent to be used.

Vulcanization by hot pressing is usually performed at a temperature of 140 to 200 ° C. for 5 to 60 minutes.
Vulcanization in a vulcanizing can is usually carried out at a temperature of 130 to 160 ° C. for 10 to 120 minutes.
If the obtained rubber laminate (including rubber hose) is further subjected to a heat treatment (post-cure) step, the time for the above vulcanization (primary vulcanization) can be shortened, and the compression set of the rubber laminate can be further increased. Improvements are also possible.

  The rubber laminate of the present invention thus obtained is excellent in cold resistance. In particular, the second layer rubber (B) preferably has a embrittlement temperature measured by a low temperature embrittlement test of −30 ° C. or less. If the embrittlement temperature of the second layer rubber (B) is too high, the rubber hose using the second layer rubber (B) as the outer layer may be cracked by impact when used in a cold region.

  The first layer rubber (A) of the rubber laminate of the present invention is excellent in oil resistance and gasoline permeation resistance, and the second layer rubber (B) is excellent in cold resistance and ozone resistance. Further, the rubber laminate of the present invention has a high adhesive strength between both layers.

  The outer layer (second layer rubber (B)) of the rubber hose of the present invention is excellent in ozone resistance. Therefore, even if the outer layer is held for 30 hours under an environment where the ozone concentration is 50 pphm and the temperature is 40 ° C., preferably, the outer layer is held for 50 hours, cracks are not visually recognized in the outer layer.

  The rubber laminate (including the rubber hose) of the present invention is useful as a fuel system hose such as a fuel hose, a filler hose, a vent bose, a breather hose, etc. of an automobile, taking advantage of the above characteristics.

  The nitrile rubber (A1), the acrylic polymer (A2), the nitrile rubber (B1), and the ethylene-α-olefin copolymer rubber (B2) preferably contain substantially no halogen. Specifically, each halogen content is preferably 0.5% by weight or less, more preferably 0.1% by weight or less, and particularly preferably 0. The smaller the halogen content, the lower the amount of halogen liberated during disposal.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples and comparative examples. In the following, “part” is based on weight unless otherwise specified. The test and evaluation of each characteristic were performed as follows.

(1) Vulcanization time [start point (t ₁₀ ) and end point (t ₉₀ )]
The vulcanization test was performed at 150 ° C. for 30 minutes using a torsional vibration type disk vulcanization tester (ODR) according to JIS K6300. Measures the time from the start of vulcanization until the torque during vulcanization of the rubber composition reaches 10% of the maximum torque [start point (t ₁₀ )] and time until it reaches 90% [end point (t ₉₀ )] did.

(2) Low temperature impact embrittlement test A low temperature impact embrittlement test was conducted according to JIS K6261 to measure the embrittlement temperature Tb (° C).

(3) Static ozone deterioration test The static ozone deterioration test was performed according to JIS K6259 at 40 ° C, ozone concentration of 50 pphm, and 30% elongation, and the visual state after 72 hours was evaluated. The evaluation was performed at the stage of NC (where no cracks were observed), C (where cracks were observed), and rupture (the cracks became large and the test piece was cut).

(4) Peel test A peel test is performed at a tensile speed of 50 mm per minute for an adhesive sheet (inner layer 2 mm / outer layer 2 mm) having a length of 100 mm, a width of 25.4 mm, and a thickness of 4 mm in accordance with JIS K6301. The strength TF (kN / m) was measured.

(5) Gasoline permeation test The gasoline permeation test was measured and evaluated by the cup method using test fuel oil CE-20 (volume ratio: isooctane / toluene / ethanol = 40/40/20). In the cup method, 50 ml of the above test fuel oil is put in a 100 ml capacity aluminum cup, and a 2 mm thick adhesive sheet (inner layer 1 mm / outer layer 1 mm, inner layer is test fuel oil) cut into a disk shape having a diameter of 61 mm. And then adjust the area separating the inside and outside of the aluminum cup with an adhesive sheet to 25.50 mm ² with fasteners, leave the aluminum cup at room temperature, and weigh every 24 hours. By measuring, the permeation amount P (unit: g · mm / cm ² · day) of the test fuel oil every 24 hours was measured, and the maximum value was taken as the permeation amount. The smaller the maximum permeation amount, the better the gasoline permeation resistance.

(6) Low-temperature impact test after single-sided immersion The low-temperature impact test after single-sided immersion was evaluated by measuring the low-temperature impact properties of the test pieces immersed on one side with fuel oil using a DuPont impact tester. 50 ml of test fuel oil CE-10 (volume ratio: isooctane / toluene / ethanol = 45/45/10) was placed in a 100 ml capacity aluminum cup, and a 4 mm thick laminate cut into a disk shape with a diameter of 61 mm. The body (inner layer 2 mm / outer layer 2 mm) was covered so that the inner layer was in contact with the test fuel oil, fastened with fasteners, and the aluminum cup was allowed to stand at room temperature for a week. Next, the laminate was removed from the aluminum cup, quickly cooled to a predetermined temperature (three types of −50 ° C., −45 ° C., and −40 ° C.) and held for 10 minutes. The cooled laminate was placed in a DuPont impact tester so that the outer layer hit the heavy cone, and a 2 kg weight (the tip of the heavy cone hitting the laminate was a semicircle with a diameter of 12 mm) was dropped from a position of 30 cm in height. . After the test, the crack occurrence state of the laminate was confirmed and evaluated according to the following criteria.
○ ... No cracks △ ... Small cracks × ... Large cracks No cracks are generated, or even if cracks occur, the lower the generation temperature, the better the low-temperature impact resistance after immersion on one side.
(Note) In the low temperature impact test after immersion on one side in the examples and comparative examples, the measurement was performed using the first layer rubber (in the case of a single layer, the single layer rubber) as the inner layer.

Example 1
First, an acrylic polymer (A2 ₁ ) was produced as follows. In a reaction vessel, 160 parts of ion exchange water, 2 parts of potassium oleate (emulsifier), 0.2 part of ammonium persulfate (polymerization initiator), 67 parts of methyl methacrylate and 33 parts of acrylonitrile are placed at a temperature of 60 ° C. with stirring. After 10 hours of polymerization, the reaction was stopped. A part of the polymerization reaction solution was sampled to find a solid concentration of 39%, and the polymerization conversion was found to be 90% by weight. The obtained acrylic polymer (A2 ₁ ) had an acrylonitrile monomer unit content of 30% by weight and an average particle size of about 0.11 μm. The particle size was measured using a light scattering particle size analyzer (model N4, manufactured by Coulter).
The acrylic polymer (A2 ₁ ) particles were dissolved in tetrahydrofuran, subjected to gel permeation chromatography, and measured using polystyrene as a standard substance. The weight average molecular weight was about 1,120,000. The polymerization reaction solution is filtered to recover the acrylic polymer (A2 ₁ ) particles. The washing operation is performed twice by dispersing in pure water, filtering and recovering, drying, and clear acrylic polymer (A2 _1). ) Particles were obtained. It was 99 degreeC when the glass transition temperature of this acrylic polymer (A2 ₁ ) was measured by the differential scanning calorimetry (DSC method). The acrylic polymer (A2 ₁ ) did not have a melting temperature.

Next, 30 parts of the acrylic polymer (A2 ₁ ) thus obtained and nitrile rubber (A1 ₁ ) [product name “Nipol DN003”, manufactured by Nippon Zeon Co., Ltd., acrylonitrile unit content 50.0% by weight, Mooney viscosity ( (ML _{1 + 4} , 100 ° C.) 78] 70 parts was kneaded using a B-type Banbury mixer (cavity temperature 50 ° C.) to prepare a polymer alloy.

To 100 parts of the obtained polymer alloy, carbon black (product name “Asahi # 60”, manufactured by Asahi Carbon Co., Ltd.) 15 parts by a B-type Banbury mixer, plasticizer adipate (product name “Adekasizer RS107”, Asahi 20 parts of Denka Co., Ltd., 1 part of stearic acid and 5 parts of zinc oxide (product name “Zinc Hana 1”, manufactured by Shodo Chemical Co., Ltd.) are added. 3 parts, 1.5 parts of vulcanization accelerator N-cyclohexyl-2-benzothiazolylsulfenamide (product name “Noxeller CZ”, manufactured by Ouchi Shinsei Chemical) and tetramethylthiuram disulfide (product name “Noxeller TT”) 1.5 parts of Ouchi Shinsei Chemical Co., Ltd.) was added to obtain a vulcanizable rubber (A ₁ ) composition.

Nitrile rubber (B1 ₁ ) [product name “Nipol 1031”, manufactured by Nippon Zeon Co., Ltd., acrylonitrile unit content: 40.5% by weight, Mooney viscosity (ML _{1 + 4} , 100 ° C.) 63] 60 parts and ethylene-α-olefin Polymer rubber (B2 ₁ ) [ethylene-propylene-conjugated diene rubber, product name “EPT4070”, manufactured by Mitsui Chemicals, ethylene unit content 68 mol%, iodine value 22, Mooney viscosity (ML _{1 + 4} , 100 ° C.) 68] 40 parts In addition, 30 parts of carbon black (product name “Seast G116”, manufactured by Tokai Carbon Co., Ltd.), 10 parts of silica (product name “Carplex 67”, manufactured by Shionogi Seiyaku Co., Ltd.), plasticizer adipate (product name “ADEKA” Sizer RS107 ", manufactured by Asahi Denka Co., Ltd.), naphthenic oil (product name" Sansen 415 ", Nippon San Oil) 5 parts, stearic acid 1 part, zinc oxide (product name "Zinc Hana 1", manufactured by Shodo Chemical Co., Ltd.) 5 parts, sulfur (325 mesh product) 1 part, and N-cyclohexyl-2-benzothiazoli 2.5 parts of rusulfenamide (product name “Noxeller CZ”, manufactured by Ouchi Shinsei Chemical Co., Ltd.) was added to obtain a vulcanizable rubber (B ₁ ) composition.

The vulcanization time (start point (t ₁₀ ) and end point (t ₉₀ )) of the vulcanizable rubber (A ₁ ) composition and the vulcanizable rubber (B ₁ ) composition thus obtained was measured. Further, press vulcanization was performed at 150 ° C. for 20 minutes to prepare vulcanized sheets each having a thickness of 2 mm, and a low temperature impact embrittlement test and a static ozone deterioration test were conducted.
Also, a vulcanizable rubber (A ₁ ) composition (which becomes the first layer rubber (A ₁ )) and a vulcanizable rubber (B ₁ ) composition (which becomes the second layer rubber (B ₁ )) are laminated. The rubber laminate (sheet) was vulcanized and bonded by press vulcanization at 150 ° C. for 20 minutes, and subjected to a peel test, a gasoline permeation test, and a low temperature impact test after one-side dipping. These test results are shown in Table 1.

Comparative Example 1
Using the vulcanizable rubber (A ₁ ) composition obtained in Example 1 without producing a rubber laminate sheet, press vulcanization was performed at 150 ° C. for 20 minutes to obtain a first layer rubber (A Only the single-layer sheet of ₁ ) was prepared, and each test in Example 1 except the peel test was performed. In addition, the gasoline permeation tests were tested at 2mm sheet of monolayers of the first layer rubber (A _1), the 4mm sheet of a single layer of the first layer rubber for low temperature impact test after one-side immersion (A ₁₎ And tested.

Comparative Example 2
Using the vulcanizable rubber (B ₁ ) composition obtained in Example 1 without producing a rubber laminate sheet, press vulcanization was performed at 150 ° C. for 20 minutes, and the second layer rubber (B Only the single-layer sheet of ₁ ) was prepared, and each test in Example 1 except the peel test was performed. In addition, the gasoline permeation tests were tested at 2mm sheet of the second layer monolayer of the rubber (B _1), the 4mm sheet of a single layer of the second layer rubber for low temperature impact test after one-side immersion (B ₁₎ And tested.

Comparative Example 3
In Example 1, vulcanizable rubber (B ₁₎ except that instead of the composition using a vulcanizable rubber (B ₂₎ The following compositions were subjected to the same experiment as in Example 1. That is, instead of 60 parts of nitrile rubber (B1 ₁ ) and 40 parts of ethylene-α-olefin copolymer rubber (B2 ₁ ), nitrile rubber (B1 ₂ ) [product name “Nipol 1032”, manufactured by Nippon Zeon Co., Ltd., acrylonitrile unit A vulcanizable rubber (B ₂ ) composition was prepared in the same manner as in Example 1 except that the content was 33.5% by weight and Mooney viscosity (ML _{1 + 4} , 100 ° C.) 51] 100 parts was used. Table 1 shows the results of the same test as in No. 1.

Comparative Example 4
In Example 1, the following vulcanizable rubber (B ₃ ) composition was used instead of the vulcanizable rubber (B ₁ ) composition, and the same procedure as in Example 1 was performed. That is, an extremely high nitrile NBR (46% by weight of acrylonitrile unit content in rubber, Mooney viscosity (ML _{1 + 4} , 100 ° C.) 95) and a polyblend of 70/30 in weight ratio of vinyl chloride resin (average degree of polymerization of resin 800) 100 parts, carbon black (product name “Asahi # 60”, manufactured by Asahi Carbon Co., Ltd.) 45 parts, plasticizer adipic acid ester (product name “Adeka Sizer RS107”, manufactured by Asahi Denka Co.), 1 part stearic acid , 5 parts of zinc oxide (product name “Zinc Hana 1”, manufactured by Shodo Chemical Co., Ltd.), 0.3 part of sulfur (product passing through 325 mesh), N-cyclohexyl-2-benzothiazolylsulfenamide (product name “ "Noxeller CZ" (made by Ouchi Shinsei Chemical Co., Ltd.) 1.5 parts and tetramethylthiuram disulfide (product name "Noxeller TT", Ouchi Shinsei Chemical Co., Ltd.) 1.5 parts The vulcanizable rubber (B ₃₎ composition was prepared Te. The results of tests similar to those in Example 1 are shown in Table 1.

As Table 1 shows, the first layer rubber (A) single layer is inferior in low-temperature impact resistance after single-sided immersion (Comparative Example 1), and the second layer rubber (B) single layer has extremely high gasoline permeability resistance. Increase (Comparative Example 2). Further, when the second layer rubber (B) is only nitrile rubber, that is, ethylene-α-olefin copolymer rubber is not used in combination, although it is excellent in low temperature impact resistance and gasoline permeation resistance after single-sided immersion, it is the outer layer. The ozone resistance of the two-layer rubber (B) was inferior (Comparative Example 3). When the polyblend of nitrile rubber and vinyl chloride resin is used for the second layer rubber (B), the second layer rubber (B), which is the outer layer, is excellent in ozone resistance and gasoline permeation resistance. Inferior in low temperature impact resistance (Comparative Example 4).
On the other hand, the first layer rubber (A) comprising the nitrile rubber (A1) and the acrylic polymer (A2) having the requirements of the present invention, the nitrile rubber (B1) and the ethylene-α-olefin copolymer rubber (B2) In the rubber laminate with the second layer rubber (B), the results show excellent resistance to gasoline permeation and low temperature impact resistance after immersion on one side, and the vulcanization time of the first layer rubber (A) Between the start point t _A10 and the end point t _A90 , the start point t _B10 or the end point t _B90 of the vulcanization time of the second layer rubber (B) is present, so that the adhesive strength between the two layers is strong, and the inner layer The first layer rubber (A) and the second layer rubber (B) as the outer layer are both excellent in ozone resistance (Example 1).

Claims (5)

A rubber laminate comprising a first layer rubber (A) and a second layer rubber (B),
The first layer rubber (A) comprises a polymer alloy composed of 40 to 90% by weight of nitrile rubber (A1) and 60 to 10% by weight of acrylic polymer (A2),
The second layer rubber (B) comprises a polymer alloy composed of 40 to 90% by weight of nitrile rubber (B1) and 60 to 10% by weight of ethylene-α-olefin copolymer rubber (B2),
Resin in which the acrylic polymer (A2) contains 35 to 99% by weight of (meth) acrylic acid ester monomer units and 65 to 1% by weight of α, β-ethylenically unsaturated nitrile monomer units A rubber laminate characterized by the above.   The rubber laminate according to claim 1, wherein the embrittlement temperature of the second layer rubber (B) is -30 ° C or lower. The start point t _B10 or the end point t _B90 of the vulcanization time of the second layer rubber (B) exists between the start point t _A10 and the end point t _A90 of the vulcanization time of the first layer rubber (A). The method for producing a rubber laminate according to claim 1 or 2, characterized in that:   The rubber hose comprising a rubber laminate according to claim 1 or 2, wherein the first layer rubber (A) is an inner layer and the second layer rubber (B) is an outer layer. The rubber hose according to claim 4, wherein the outer layer has ozone resistance so that cracks are not visually recognized even if the outer layer is kept in an extended state of 30% in an environment having an ozone concentration of 50 pphm and a temperature of 40 ° C. for 72 hours.