JPH09316414A - Rubber adhesive composition and production of rubber composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composite excellent in bond strength, esp. bond strength under flexural fatigue by jointing a sulfur-based curing agent-contg. sulfur-curable rubber composition to an organic peroxide curing agent-contg. organic peroxide-curable rubber composition followed by curing into integration. SOLUTION: This rubber adhesive composition consisting mainly of an ethylenic unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber <=120 in iodine value and an organic solvent and free from both organic peroxide curing agent and sulfur-based during agent is put between a curable rubber composition comprising an uncured rubber and a sulfur-based curing agent and another curable rubber composition comprising an uncured rubber and an organic peroxide curing agent, followed by jointing both the curable rubber compositions and then carrying out a curing into integration, thus obtaining the other objective rubber composite.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a rubber composite, which comprises joining an organic peroxide vulcanizable rubber composition and a sulfur vulcanizable rubber composition and integrally vulcanizing them. It relates to a rubber adhesive composition used for producing such a rubber composite.

[0002]

2. Description of the Related Art Each rubber material has its own field of application in order to utilize its unique characteristics. For example, many rubber products such as tires, crawlers / caterpillars, rubber rolls, belts, molds, hoses, etc. have been used for a long time with oil heated under high temperature, and the rubber products Since deterioration is a serious problem, oil resistance and heat aging resistance are required, and abrasion resistance and tear resistance are also required. As a raw material rubber for these rubber products, conventionally, a diene elastomer such as a natural rubber (NR), a butadiene rubber (BR), a styrene-butadiene copolymer rubber (SBR), or an acrylonitrile-butadiene copolymer rubber (NBR) has been used. Sulfur-based compound vulcanizable rubber compositions have been used, but in recent years, NBR, acrylonitrile-
There is a great demand for organic peroxide vulcanizable rubber compositions of isoprene-butadiene copolymer rubber (NBIR), acrylonitrile-isoprene copolymer rubber (NIR) and rubbers obtained by hydrogenating their conjugated diene moieties.

Among these rubber products, there is a high demand for a rubber composite in which two or more kinds of rubbers are combined depending on the application. For example, in rubber rolls and hoses that come into contact with oil at high temperatures, NBR hydrogenated products (HNBR) with good heat aging resistance, wear resistance and oil resistance are arranged in the outer layer, and the inner layer has cost and processing surface From a viewpoint, a composite rubber structure in which a diene elastomer is arranged is used. Further, as an oil hose used for feeding oil under high temperature, NBR having particularly high oil resistance was arranged in the inner layer, and HNBR having high heat aging resistance, wear resistance and strength characteristics was arranged in the outer layer. Composite rubber structures are desired. As a method for producing such a composite rubber structure, a vulcanizable rubber composition using a sulfur-based vulcanizing agent and a vulcanizable rubber composition using an organic peroxide vulcanizing agent is used. A rubber composite is manufactured by joining two types of vulcanizable rubbers of different systems and vulcanizing and integrating them. In this case, a sufficiently high adhesive strength is obtained at the interface between the two vulcanizable rubbers. There is a problem that you can not.

For example, JP-A-5-186609 discloses a rubber composition containing HNBR, methacrylic acid, zinc oxide and an organic peroxide vulcanizing agent, NBR or an isobutylene / isoprene copolymer rubber and a sulfur-based compound. It is described that a sulfur-vulcanizable rubber composition containing a vulcanizing agent is directly bonded and vulcanized integrally without using an adhesive or the like. However, in this vulcanized integrated product, although the adhesive strength in the static state is improved, the adhesive strength in the dynamic state, especially the adhesive strength at the time of repeated bending fatigue is not sufficient, and it is necessary to further improve it. did. It is considered that the reason is that the sulfur-based vulcanizing agent and the organic peroxide vulcanizing agent react with each other at the interface between both rubbers and are consumed, and a sufficient cross-linking bond is not formed between both rubbers.

On the other hand, when a plurality of adherends made of a vulcanizable rubber composition containing an unvulcanized ethylene elastomer and an organic peroxide vulcanizing agent are vulcanized and integrated, HNBR and organic peroxide are used. A method has been reported in which an adhesive prepared by dissolving a material vulcanizing agent in a solvent is applied between adherends and then pressure-vulcanized (Japanese Patent Application Laid-Open No. 2-123183). However, in this method, when the vulcanizing agent to be added to the vulcanizable rubber composition and the adhesive is a co-functional peroxide vulcanizing agent, the adhesion between adherends can be enhanced. However, in the case of pressure vulcanization of adherends with different vulcanizing agents, the vulcanizing agent in the adhesive reacts with the vulcanizing agent in the adherend and is consumed. I can't get strength.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a sulfur vulcanizable rubber composition containing a sulfur vulcanizing agent and an organic peroxide vulcanizing agent. An organic peroxide vulcanizable rubber containing is bonded and vulcanized and integrated to provide a rubber composite having excellent adhesive strength, particularly adhesive strength during bending fatigue. Another object of the present invention is to provide a rubber adhesive composition used for producing such a rubber composite.

[0007]

DISCLOSURE OF THE INVENTION The inventors have found that an organic peroxide vulcanizable rubber containing an ethylenically unsaturated nitrile-conjugated diene highly saturated copolymer rubber, and an ethylenically unsaturated nitrile-conjugated diene copolymer. As a result of repeated studies for vulcanizing and adhering a sulfur vulcanizable rubber composition containing a coalesced rubber, one of the vulcanizable rubber compositions has an ethylenically unsaturated nitrile-
A solution of a conjugated diene highly saturated copolymer rubber in methyl ethyl ketone, which contains neither an organic peroxide vulcanizing agent nor a sulfur-based vulcanizing agent involved in vulcanization of these unvulcanized rubbers, is applied. , By vulcanizing and adhering both vulcanizable rubbers through the coating layer, it was found that a rubber laminate excellent in adhesive strength during flexural fatigue can be obtained, and based on this finding, the present invention was completed. I arrived.

Thus, according to the present invention, in one aspect thereof, a vulcanizable rubber composition (I) containing an unvulcanized rubber and an organic peroxide vulcanizing agent, an unvulcanized rubber and a sulfur-based compound A rubber composite by interposing it between a vulcanizable rubber composition (II) containing a vulcanizing agent and then vulcanizing and integrating both vulcanizable rubber compositions (I) and (II). An adhesive used for the production of an organic peroxide vulcanizing agent, which comprises an ethylenically unsaturated nitrile-conjugated diene highly saturated copolymer rubber having an iodine value of 120 or less and an organic solvent as main components. There is provided a rubber adhesive composition characterized by containing neither a sulfur-based vulcanizing agent.

Further, according to the present invention, in another aspect, a vulcanizable rubber composition (I) containing an unvulcanized rubber and an organic peroxide vulcanizing agent, an unvulcanized rubber and sulfur. A vulcanizable rubber composition (II) containing a vulcanizing agent is bonded to form a composite of the vulcanizable rubber compositions (I) and (II) with the vulcanizable rubber composition. A method for producing, wherein at least one of the vulcanizable rubber compositions (I) and (II) has an iodine value of 120 or less, an ethylenically unsaturated nitrile-
A rubber adhesive composition containing a conjugated diene-based highly saturated copolymer rubber and an organic solvent as main components and containing neither an organic peroxide vulcanizing agent nor a sulfur-based vulcanizing agent is applied, and the rubber is obtained. The above vulcanizable rubber compositions (I) and (II) are joined so that the coating layer of the adhesive composition is interposed, and then the both vulcanizable rubber compositions (I) and (II) are added. Provided is a method for producing a rubber composite, which is characterized in that it is integrated with sulfur.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The adherend rubber which is made into a rubber composite using the rubber adhesive composition of the present invention is an unvulcanized rubber and an organic peroxide vulcanizing agent containing an organic peroxide vulcanizing agent. And a sulfur-vulcanizable rubber composition (II) containing an unvulcanized rubber and a sulfur-based vulcanizing agent.

The rubber used in the organic peroxide vulcanizable rubber composition (I) is a rubber which is vulcanized by an organic peroxide vulcanizing agent, and its specific example is acrylonitrile-butadiene copolymer. Ethylenically unsaturated nitrile-conjugated diene copolymer rubber typified by polymer rubber (NBR), hydrogenation of ethylenically unsaturated nitrile conjugated diene copolymer rubber typified by hydrogenated NBR (HNBR) Unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber, butadiene rubber (BR)
Conjugated diene polymer rubber represented by styrene-
Conjugated diene-aromatic vinyl compound copolymer rubber represented by butadiene copolymer rubber (SBR), SBR
Of a conjugated diene-aromatic vinyl compound copolymer rubber represented by a partial hydride of ethylene, ethylene-
Examples thereof include propylene-diene terpolymer rubber (EPDM) and ethylene-propylene copolymer rubber (EPR). Among these, the ethylenically unsaturated nitrile-conjugated diene copolymer rubber and its hydrogenated product are preferably used for the production of the rubber composite of the present invention.

The rubber used in the sulfur vulcanizable rubber composition (II) is a rubber which is vulcanized by sulfur or a sulfur compound vulcanizing agent, and specific examples thereof include natural rubber (N
R), isoprene rubber (IR), butadiene rubber (B
R), styrene-butadiene copolymer rubber (SBR) and acrylonitrile-isoprene copolymer rubber (NI
R) represented by conjugated diene polymer rubber, butyl rubber (IIR), ethylene-propylene-diene terpolymer rubber (EPDM), ethylenically unsaturated nitrile-conjugated diene copolymer rubber represented by NBR And an ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber represented by HNBR. Among these, natural rubber (NR), conjugated diene polymer rubbers such as IR and BR, and conjugated diene-aromatic vinyl compound copolymer rubbers such as SBR are preferably used for producing the rubber composite of the present invention. .

Hereinafter, typical rubbers will be described. (Ethylene unsaturated nitrile-conjugated diene-based copolymer rubber and ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber) Organic peroxide vulcanizable rubber composition (I)
Of the ethylenically unsaturated nitrile-conjugated diene copolymer rubber (hereinafter, referred to as "nitrile-conjugated diene copolymer rubber", which is preferably used for the preparation of the sulfur-vulcanizable rubber composition (II). Is a copolymer of unsaturated nitrile-conjugated diene- (a further copolymerizable monomer if desired), which usually has a Mooney viscosity of 1
5 to 200, preferably 30 to 100. Also,
Similarly, the ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber (hereinafter, referred to as "nitrile-conjugated" which is preferably used for the preparation of the rubber composition (I) and also for the preparation of the rubber composition (II). "Diene-based highly saturated copolymer rubber" is abbreviated as "hydrogenated conjugated diene moiety" of a copolymer composed of unsaturated nitrile-conjugated diene- (a further copolymerizable monomer, if desired). And usually
Mooney viscosity of 15 to 200, preferably 30 to 10
0, iodine value is 120 or less, preferably 60 or less. When the Mooney viscosity is less than 15, the strength decreases, which is not preferable. If it exceeds 200, the viscosity increases and molding becomes difficult.

The content of the bound unsaturated nitrile unit in the copolymer is 10 to 60% by weight, preferably 15 to 45% by weight. Specific examples of unsaturated nitriles include acrylonitrile, methacrylonitrile, and α-chloroacrylonitrile. Of these, acrylonitrile is preferred. Specific examples of the conjugated diene include:
1,3-butadiene, 2,3-dimethylbutadiene, isoprene, 1,3-pentadiene and the like can be mentioned. Of these, butadiene is preferred.

If desired, in addition to the unsaturated nitrile and the conjugated diene, further unsaturated carboxylic acid esters or other copolymerizable monomers are copolymerized. Specific examples of the unsaturated carboxylic acid ester to be copolymerized include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isononyl acrylate, n-hexyl acrylate. , 2-methyl-pentyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-
Acrylate and methacrylate having an alkyl group having about 1 to 18 carbon atoms such as dodecyl acrylate, methyl methacrylate, and ethyl methacrylate;

Acrylates having an alkoxyalkyl group having about 2 to 12 carbon atoms such as methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, ethoxypropyl acrylate, methoxyethoxy acrylate and ethoxybutoxy acrylate; α- and β An acrylate having a cyanoalkyl group having about 2 to 12 carbon atoms such as cyanoethyl acrylate, α-, β- and γ-cyanopropyl acrylate, cyanobutyl acrylate, cyanohexyl acrylate, and cyanooctyl acrylate;

Acrylate having a hydroxyalkyl group such as 2-hydroxyethyl acrylate and hydroxypropyl acrylate; monoethyl maleate, dimethyl maleate, dimethyl fumarate, diethyl fumarate, di-n-butyl fumarate, di-2 fumarate. -Ethylhexyl, dimethyl itaconate, diethyl itaconate,
Unsaturated dicarboxylic acid mono- and dialkyl esters such as di-n-butyl itaconate and di-2-ethylhexyl itaconate;

Further, dimethylaminomethyl acrylate, diethylaminoethyl acrylate, 3- (diethylamino) -2-hydroxypropyl acrylate,
Amino group-containing unsaturated carboxylic acid ester-based monomer such as 2,3-bis (difluoroamino) propyl acrylate;

Trifluoroethyl acrylate, tetrafluoropropyl acrylate, pentafluoropropyl acrylate, heptal orobutyl acrylate, octafluoropentyl acrylate, nonafluoropentyl acrylate, undecafluorohexyl acrylate, pentadecafluorooctyl acrylate, heptadecafluorononyl Fluoroalkyl groups such as acrylate, heptadecafluorodecyl acrylate, nonadecafluorodecyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, octafluoropentyl methacrylate, dodecafluoroheptyl methacrylate, pentadecafluorooctyl acrylate, hexadecafluorononyl methacrylate Have Acrylate and methacrylate;

Fluorine-substituted benzyl acrylates and methacrylates such as fluorobenzyl acrylate, fluorobenzyl methacrylate and difluorobenzyl methacrylate can be mentioned. Among these unsaturated carboxylic acid esters, unsaturated dicarboxylic acid dialkyl esters are preferable.

Other copolymerizable monomers other than the above unsaturated carboxylic acid esters include vinyl monomers such as styrene, α-methylstyrene and vinylpyridine; vinyl norbornene, dicyclopentadiene, 1,4. Non-conjugated diene-based monomers such as hexadiene; fluoroethyl vinyl ether, fluoropropyl vinyl ether, trifluoromethyl vinyl ether, trifluoroethyl vinyl ether, perfluoropropyl vinyl ether,
Fluoroalkyl vinyl ethers such as perfluorohexyl vinyl ether, fluorine-containing vinyl-based monomers such as o- or p-trifluoromethylstyrene, vinyl pentafluorobenzoate, difluoroethylene, tetrafluoroethylene; Saturated monocarboxylic acids; unsaturated dicarboxylic acids or anhydrides such as itaconic acid, fumaric acid, maleic acid; further, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate And so on.

The amount of the unsaturated carboxylic acid ester-based monomer or other copolymerizable monomer used is 1 to 80% by weight, preferably 15 to 60% by weight, and more preferably the total amount of the monomers. It can be used in the range of 20 to 50% by weight.

The method for hydrogenating the nitrile-conjugated diene-based copolymer to obtain the nitrile-conjugated diene-based highly saturated copolymer is not particularly limited, and hydrogenation can be performed according to a conventional method. Examples of the catalyst used in the hydrogenation include palladium / silica and palladium complex (JP-A-3-252405). Further, JP-A-62-125858 and JP-A-62-429.
37, JP-A-1-45402, JP-A-1-4540
3, JP-A-1-45404, JP-A-1-45405.
Rhodium or ruthenium compounds such as those described in US Pat.

The nitrile-conjugated diene-based highly saturated copolymer rubber can also be obtained by directly hydrogenating the latex of the nitrile-conjugated diene-based copolymer. As a method for direct hydrogenation, a method using a palladium-based catalyst (for example, JP-A-2-178305) and a method using a rhodium-based catalyst (for example, JP-A-59-1153).
03, JP-A-56-133219, U.S. Pat. No. 3,
898, 208) and a method using a ruthenium-based catalyst (for example, JP-A-6-184223 and JP-A-6-184223).
No. 192323) and the like, but are not limited thereto. As a specific example, when a palladium-based catalyst is used, an organic solvent that dissolves or swells a nitrile-conjugated diene-based copolymer is used as described in JP-A-2-178305. The method of adding in latex is adopted. According to this method, the nitrile-conjugated diene-based copolymer in the copolymer latex is swollen with an organic solvent, and the hydrogenation catalyst can be easily approached to the double bond in the copolymer. The hydrogenation reaction can be efficiently performed while maintaining the emulsion state.

Specific examples of the nitrile-conjugated diene-based copolymer rubber include acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-isoprene copolymer rubber (NIR), acrylonitrile-butadiene-acrylate copolymer rubber. , Acrylonitrile-butadiene-acrylate-methacrylic acid copolymer rubber, acrylonitrile butadiene-acrylate-methacrylic acid copolymer rubber, and the like. Further, specific examples of the nitrile conjugated diene-based highly saturated copolymer rubber include hydrogenated copolymer rubbers corresponding to these nitrile-conjugated diene-based copolymer rubbers.

(Conjugated Diene Polymer Rubber) Conjugated diene preferably used for preparing the sulfur vulcanizable rubber composition (II) and also for preparing the organic peroxide vulcanizable rubber composition (I). The polymer rubber is not particularly limited as long as it is a polymer rubber mainly containing a conjugated diene. Specific examples thereof include natural rubber (NR) and polyisoprene rubber (I).
R), emulsion-polymerized styrene-butadiene copolymer rubber (E-
SBR), solution polymerization random SBR (S-SBR, bound styrene 5 to 50% by weight, 1,2-bond amount of butadiene bond unit portion 10 to 80%), high trans SBR (trans amount of butadiene bond unit portion 70 to 70%). 95%), low cis polybutadiene rubber (BR), high cis BR, high trans BR (trans amount of butadiene bond unit part 70 to 70).
95%), styrene-isoprene copolymer rubber (SI
R), butadiene-isoprene copolymer rubber, solution polymerization random styrene-butadiene-isoprene copolymer rubber (SIBR), emulsion polymerization SIBR, high vinyl SBR-low vinyl SBR block copolymer rubber, polystyrene-polybutadiene-polystyrene block copolymer Examples thereof include block copolymers such as polymers, unsaturated nitrile-butadiene-isoprene terpolymer (NBIR), and acrylonitrile-isoprene copolymer (NIR).
Among these, NR, BR and SBR are preferable.
Two or more kinds of these conjugated diene polymer rubbers may be blended and used.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the conjugated diene polymer rubber component is not particularly limited, but is usually 10 to 250, preferably 20 to 150, more preferably 25 to 120. Is. When the Mooney viscosity is in this range, heat generation, abrasion resistance, workability, etc. are excellent and well balanced, which is preferable. Mooney viscosity of conjugated diene polymer rubber component (ML _{1 + 4} , 100 ° C)
May be adjusted within this range as an oil-extended rubber to which oil or the like is added.

(Olefin Polymer Rubber) The olefin polymer rubber used for preparing the organic peroxide vulcanizable rubber (I) and the sulfur vulcanizable rubber (II) is an ethylene-propylene copolymer rubber. (EPM), ethylene-propylene-diene terpolymer rubber (EPDM), butyl rubber (IIR) and the like.

(Metal salt of α, β-ethylenically unsaturated carboxylic acid, and other compounding agents) Organic peroxide vulcanizable rubber composition (I) and sulfur vulcanizable rubber composition (II) , If necessary, a conventional compounding agent used in the rubber field, for example, a reinforcing agent (carbon black, silica,
Talc etc.), fillers (calcium carbonate, clay etc.), processing aids, process oils, antioxidants, antiozonants, vulcanization aids, coloring aids and the like can be added. Furthermore, if necessary, other rubbers such as acrylic rubber and fluororubber, and an ethylene-vinyl acetate copolymer resin can be blended.

Further, a metal salt of α, β-ethylenically unsaturated carboxylic acid can be blended with the nitrile-conjugated diene-based highly saturated copolymer rubber, and depending on the blending, tensile strength, abrasion resistance, etc. Can be improved. α, β-
The metal salt of ethylenically unsaturated carboxylic acid may be (1) compounded with a nitrile group-containing highly saturated copolymer rubber in the form of a carboxylic acid metal salt, or (2) a nitrile group-containing highly saturated copolymer. The α, β-ethylenically unsaturated carboxylic acid and the metal compound are blended with the integrated rubber, and
The metal salt of α, β-ethylenically unsaturated carboxylic acid may be formed by the reaction in situ.

The metal compound is not particularly limited as long as it forms a salt with an α, β-ethylenically unsaturated carboxylic acid, but zinc, aluminum, magnesium and calcium compounds are especially preferred. The metal compound is used in the form of oxide, hydroxide, peroxide and the like.
Among the metal compounds, the zinc compound is most preferable. Examples of the zinc compound include zinc oxide, zinc carbonate, zinc hydroxide and the like.

Examples of the α, β-ethylenically unsaturated carboxylic acid include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and 3-butenoic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid. Acids; monoesters of unsaturated dicarboxylic acids such as monomethyl maleate, monomethyl fumarate and monomethyl itaconate; unsaturated polycarboxylic acids other than the above; unsaturated polycarboxylic acids having at least a monovalent free carboxyl group And the like. Among these, methacrylic acid is particularly preferable from the viewpoints of good physical properties and easy availability.

The metal compound and the α, β-ethylenically unsaturated carboxylic acid are added to the nitrile-conjugated diene-based highly saturated copolymer rubber and reacted in situ in the copolymer rubber compound to obtain α When a metal salt of β-ethylenically unsaturated carboxylic acid is produced, coarse particles having a particle size of 20 μm or more are previously removed by classification as a metal compound, and the content rate of the coarse particles is set to 5% by weight or less. Is preferable for improving strength characteristics such as tensile strength of the vulcanized rubber. Also, when adding in the form of a metal salt of α, β-ethylenically unsaturated carboxylic acid, it is preferable to use the one from which coarse particles are similarly removed.

The molar ratio of the α, β-ethylenically unsaturated carboxylic acid to the metal compound is usually calculated on the basis of the molecular weight of the α, β-ethylenically unsaturated carboxylic acid and the formula weight of the metal compound. It is in the range of 1: 0.5 to 1: 3.2, preferably 1: 0.5 to 1: 2.5. The amount of the metal salt of α, β-ethylenically unsaturated carboxylic acid to be compounded is 10 based on 100 parts by weight of the nitrile-conjugated diene-based highly saturated copolymer rubber.
˜150 parts by weight, preferably 10 to 100 parts by weight.

(Organic peroxide vulcanizing agent) The organic peroxide vulcanizable rubber composition (I) contains an organic peroxide as a vulcanizing agent. The organic peroxide-based vulcanizing agent is not particularly limited as long as it can be used in the usual peroxide vulcanization of rubber. Specific examples thereof include dicumyl peroxide,
Di-t-butyl peroxide, t-butyl cumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-
3,2,5-Dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-mono (t
-Butylperoxy) hexane, α, α'-bis (t-
Butyl peroxy-m-isopropyl) benzene and the like. These organic peroxides can be used alone or in combination of two or more. As the organic peroxide, one having a decomposition temperature that does not cause scorch during kneading is preferable.

These organic peroxides are used in an amount of 0.2 to 10 parts by weight, based on 100 parts by weight of the organic peroxide vulcanizable rubber.
It is preferably used in the range of 0.4 to 8 parts by weight. If it is out of this range, a vulcanized rubber having good physical properties cannot be obtained at high temperature. Further, a crosslinking aid can be used. The cross-linking aid usually includes unsaturated compounds used as a cross-linking aid in organic peroxide vulcanization.
Examples include ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, N,
Examples thereof include N'-m-phenylene dimaleimide and triallyl isocyanurate. Of these, triallyl isocyanurate is preferable from the viewpoint of vulcanization properties. The addition amount of these is 0.1 per 100 parts by weight of the organic peroxide vulcanizable rubber.
-15 parts by weight.

(Sulfur-Based Vulcanizing Agent) The sulfur-vulcanizable rubber composition (II) contains sulfur or a sulfur compound (both are collectively referred to as “sulfur-based vulcanizing agent”) as a vulcanizing agent. The sulfur-based vulcanizing agent is not particularly limited, for example, powdered sulfur,
Sulfur such as precipitated sulfur, colloidal sulfur, insoluble sulfur and highly dispersible sulfur; sulfur halide such as sulfur monochloride and sulfur dichloride. Among these, sulfur is preferable, and powdered sulfur is particularly preferable. These sulfur-based vulcanizing agents may be used alone or in combination of two or more.

The mixing ratio of the sulfur-based vulcanizing agent is usually 0.1 to 15 parts by weight, preferably 0.3 to 10 parts by weight, more preferably 0, relative to 100 parts by weight of the sulfur vulcanizable rubber component. It is in the range of 0.5 to 5 parts by weight. When the compounding ratio of the sulfur-based vulcanizing agent is within this range, a vulcanized product excellent in properties such as heat resistance and residual strain as well as tensile strength and abrasion resistance can be obtained.

A vulcanization accelerator is generally used in combination with the sulfur-based vulcanizing agent. Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, N-
t-butyl-2-benzothiazole sulfenamide,
Sulfenamide vulcanization accelerators such as N-oxyethylene-2-benzothiazolephenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide; Guanidine vulcanization accelerators such as diphenylguanidine, dioltotolylguanidine, orthotolylbiguanidine; thiourea vulcanization accelerators such as thiocarbanilide, diortotolylthiourea, ethylenethiourea, diethylthiourea, trimethylthiourea; 2
-Mercaptobenzothiazole, dibenzothiazyl disulfide, 2-mercaptobenzothiazole zinc salt, 2
-Mercaptobenzothiazole sodium salt, 2-mercaptobenzothiazole cyclohexylamine salt,
Thiazole-based vulcanization accelerators such as (2,4-dinitrophenylthio) benzothiazole; thiuram-based accelerators such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and dipentamethylenethiuram tetrasulfide. Vulcanization accelerator: sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium di-n-butyldithiocarbamate, lead dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, pentamethylene Zinc dithiocarbamate, zinc ethylphenyldithiocarbamate, tellurium diethyldithiocarbamate, dimethyldithiocarba Dithiocarbamic acid-based vulcanization accelerators such as selenium acid selenium, selenium diethyldithiocarbamate, copper dimethyldithiocarbamate, iron dimethyldithiocarbamate, diethylamine diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, and pipecoline methylpentamethylenedithiocarbamate; sodium isopropylxanthogenate , Xanthogen acid-based vulcanization accelerators such as zinc isopropylxanthate and zinc butylxanthogenate; and vulcanization accelerators.

Each of these vulcanization accelerators alone is
Alternatively, two or more of them may be used in combination, but one containing at least a sulfenamide vulcanization accelerator is particularly preferable. The compounding ratio of the vulcanization accelerator is the sulfur vulcanizable rubber component 1
0.1 to 15 parts by weight, preferably 0.3 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight with respect to 00 parts by weight.
The range is parts by weight.

(Rubber adhesive composition) Organic peroxide vulcanizable rubber composition (I) Adherent and sulfur vulcanizable rubber composition (II)
The adhesive composition of the present invention used for adhesion to an adherend contains an ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber having an iodine value of 120 or less and an organic solvent as main components. The nitrile-conjugated diene-based highly saturated copolymer rubber is the same as the above-mentioned nitrile-conjugated diene-based highly saturated copolymer rubber that is preferably used for the preparation of the organic peroxide vulcanizable rubber composition (I). Rubber can be used.

The organic solvent is compatible with nitrile-conjugated diene highly saturated copolymer rubber having an iodine value of 120 or less,
Further, a solvent that volatilizes moderately at room temperature is preferable, and specific examples thereof include a ketone solvent such as acetone and methyl ethyl ketone and an aromatic solvent such as benzene and toluene, and methyl ethyl ketone is particularly preferable. The ratio of the nitrile-conjugated diene-based highly saturated copolymer rubber in the adhesive composition is usually 3 to 50% by weight, preferably 5 to 35% by weight, as the ratio of the rubber (polymer) to the solvent. . If it is less than 3% by weight, the adhesive rubber composition layer becomes too thin to obtain a sufficient adhesive effect, and if it exceeds 50% by weight, the solution viscosity becomes high and the coating workability deteriorates. It becomes non-uniform and a sufficient adhesive effect cannot be obtained.

In the rubber adhesive composition, if desired, a metal of α, β-ethylenically unsaturated carboxylic acid can be used, as in the case of the nitrile-conjugated diene-based highly saturated copolymer rubber as the adherend. A salt can be added. Blended α,
The amount of the metal salt of β-ethylenically unsaturated carboxylic acid is preferably 150 parts by weight or less, particularly 10 to 150 parts by weight, based on 100 parts by weight of the nitrile-conjugated diene-based highly saturated copolymer rubber.

Further, if desired, in the rubber adhesive composition, a phenol resin system, an α-olefin resin system, an epoxy resin system, a phenol resin-epoxyphenol system,
Phenol resin-chlorinated rubber type, chlorinated rubber type, brominated chlorinated butadiene rubber, natural rubber type, nitrile rubber type,
A commercially available adhesive such as an organic silicon type or an isocyanate type may be added. Among these adhesives, chlorinated rubber adhesives and isocyanate adhesives are preferable. As the chlorinated rubber adhesive, those having a chlorination degree of 20 to 80 are preferable. Examples of the isocyanate adhesive include those containing methylene di- (phenyl cyanate), toluene diisocyanate, triphenylmethane triisocyanate, and naphthalene diisocyanate as main components.

The amount of the above-mentioned adhesive compounded is 5, based on 100 parts by weight of the nitrile-conjugated diene-based highly saturated copolymer rubber.
It is preferably 000 parts by weight or less, particularly 30 to 5,000 parts by weight. Further, the rubber adhesive composition, if necessary,
A rubber composition may be obtained by compounding and kneading a compounding agent such as a reinforcing agent such as carbon or silica, a filler, a plasticizer, an antioxidant and a lubricant.

The rubber adhesive composition of the present invention must not contain a sulfur-based vulcanizing agent or an organic peroxide vulcanizing agent which participates in vulcanization of unvulcanized rubber. When the vulcanizing agent compositions (I) and (II) are joined with the coating layer of the rubber adhesive composition containing a sulfur vulcanizing agent or an organic peroxide vulcanizing agent interposed, the rubber adhesive composition The vulcanizing agent in the product reacts with the vulcanizing agent compounded in the vulcanizing agent composition (I) or (II) different from the vulcanizing agent, which is consumed and a sufficient cross-linking bond is formed between the two compositions. Therefore, it is not possible to form a rubber composite body integrated with vulcanization.

(Production of Rubber Composite) At least one of the organic peroxide vulcanizable rubber composition (I) and the sulfur vulcanizable rubber composition (II) is added to the above nitrile-conjugated diene-based highly saturated copolymer. A rubber adhesive composition containing rubber is applied, and both the vulcanizable rubber compositions (I) and (II) are vulcanized and integrated so that a coating layer of the rubber adhesive composition is present. A rubber composite is produced. More specifically, a known coating method such as brush coating can be used for applying the rubber adhesive composition, and after application, it is usually air-dried at room temperature for 30 minutes or more.

After that, both the adherends are laminated so that the rubber adhesive composition layer is interposed between the adherends, and then the ordinary method is conducted under ordinary conditions, for example, at a temperature of 120 to 200 ° C.
For example, both adherends are adhered by vulcanization and integration by a method such as press vulcanization, steam vulcanization, and hot water vulcanization. At this time, the intervening rubber adhesive composition layer is cross-linked by the vulcanizing agent diffusing from both vulcanizable rubber layers, and since the rubber adhesive composition layer is present, both vulcanizable rubber layers are on the other side. It is considered that the reaction inhibition of the rubber layer due to the vulcanizing agent is less likely to occur, and as a result, the adhesiveness between the two vulcanizable rubber layers is improved.

For the purpose of obtaining a rubber composite having higher strength, a reinforcing layer can be interposed between both vulcanizable rubber layers.
In this case, the rubber composition adhesive is applied to both rubber adherends as described above, and a reinforcing layer is interposed between both applied surfaces to be laminated. Alternatively, the rubber adhesive composition is impregnated into the reinforcing layer and dried at room temperature for 30 minutes or more, and then the adhesive impregnated reinforcing layer is interposed between both rubber adherends. The vulcanization and integration method can be performed by the same method as described above.

The reinforcing layer can be made of a fibrous material, and the fibrous material may be in any form such as knitted woven fabric, non-woven web and long fiber strand. As the fibrous material, commonly used ones such as organic fibers such as polyester fibers and polyamide fibers, and inorganic fibers such as glass fibers and steel fibers are used. The rubber composite manufactured as described above is used for the same purpose as that of a rubber laminate which has been generally manufactured conventionally. Examples of preferred applications include
Pneumatic tires, solid tires, crawler tracks, rubber rolls and hoses.

[0051]

EXAMPLES Examples of the rubber adhesive composition of the present invention, and an organic peroxide vulcanizable rubber composition (I) and a sulfur vulcanizable rubber composition (II) using the same will be described below. The composite method will be specifically described. (Preparation of Vulcanizable Rubber Composition) Table 1 shows an organic peroxide vulcanizable rubber composition of ethylenically unsaturated nitrile-conjugated diene copolymer rubber (adherent 1), and Table 2 shows a diene elastomer. The respective compositions of the sulfur-based compound vulcanizable rubber composition (adherend 2) are shown.

Table 3 shows the composition of an ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber composition having an iodine value of 120 or less for an adhesive and a commercially available adhesive. Each rubber composition sample was prepared by mixing on a 6-inch mixing roll at 60 ° C. for 15 minutes, and then sheeting out to a thickness of about 2.3 mm.

(Production and Evaluation of Composite) As shown in Tables 4 and 5 and Tables 6 and 7, the vulcanizable rubber composition adherend and the rubber adhesive composition were combined and the resulting mixture was subjected to 160 press molding.
Pressure vulcanization was performed at a pressing pressure of 40 kgf / cm ² for 30 minutes at a temperature of 50 ° C., and molding and integration were performed to obtain a vulcanized product of 120 × 120 × 4 mm. This is left at 23 ℃ for 24 hours, then 100 × 2
It was cut into 5.4 × 4 mm and subjected to an adhesion test.

For bending fatigue, the same sample as above was JIS K
6301 Demacha-type tester specified in 15.3.
Bending was performed for, 000,000 times. The bending fatigue condition was a maximum distance of 50 mm between grips and a minimum distance of 30 mm, and reciprocation was performed at a speed of 300 times / minute.

The adhesiveness was measured at a tensile speed of 50 mm / min using a tensile tester specified in JIS K6301. Since the adhesiveness of the rubber / rubber adhesive laminate is not accurate to evaluate by its adhesive strength, it was judged by its peeling state. The peeled state includes destruction of the adherend rubber material, destruction of the rubber material and the rubber adhesive layer, and destruction of the adhesive layer. Of these, the greater the degree of destruction of the adherend rubber material, the better the adhesiveness, and the adhesiveness test was performed four times with the same material, and the average value of the rate of destruction of each adherend rubber material was measured. Rubber destruction rate (%) ”. This is JIS K6
Reference is made to "Type of adhesive failure" specified in 301 8.4.

Adhesion was judged according to the following criteria. ⊚: “Rubber destruction ratio (%)” was 9 at the beginning and after fatigue
0% or more ○: "Rubber destruction rate (%)" is 8 at the beginning and after fatigue
0% or more x: "Rubber breakage rate (%)" is 70% or more in the initial stage and lower than 70% after fatigue XX: "Rubber breakage rate (%)" is 70% or more in the initial stage and after the fatigue Low one

Examples 1 to 6 and Comparative Examples 1 to 6 (Table 4) are
The effect of the presence or absence of the rubber adhesive composition of the present invention is shown. Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, Example 4 and Comparative Example 4, Example 5 and Comparative Example 5, and Example 6 and Comparative Example 6 were compared. As a result, it can be seen that in any combination of adherends, by using the rubber adhesive of the present invention, a rubber composite having excellent adhesiveness, particularly adhesiveness after bending fatigue can be obtained.

Examples 7 to 10 and Comparative Examples 7 to 10 (Table 5)
Is a comparison between the rubber adhesive composition of the present invention and the conventionally used adhesive. Example 7 is the rubber adhesive composition used in Comparative Example 7 from which the organic peroxide that is the vulcanizing agent is removed. By using the rubber adhesive composition from which the organic peroxide is removed, It can be seen that a rubber composite having excellent adhesiveness after bending fatigue can be obtained.

Comparative Example 8 is Japanese Patent Laid-Open No. 123183/1990.
Example 7 using a rubber adhesive composition obtained by mixing an organic sulfur-containing compound disclosed in JP-A No. 2000-242242 and an organic peroxide vulcanizing agent, but using a rubber adhesive containing no such compounds. It can be seen that is excellent in adhesiveness. Further, Comparative Examples 9 and 10 are those in which only the chlorinated rubber-based and phenol resin-based adhesives are applied to the adherend, but compared with Examples 7 to 10 using the rubber adhesive composition of the present invention. It turns out that it is inferior in sex. In particular, it can be seen that Comparative Example 10 using only the phenol resin adhesive is significantly inferior in adhesiveness.

[0060]

The organic peroxide vulcanizable rubber composition (I) and the sulfur vulcanizable rubber composition (II) are combined with the nitrile-conjugated diene-based highly saturated copolymer rubber adhesive composition of the present invention. The rubber composite obtained by adhesion and vulcanization and integration using the two vulcanizable rubber compositions (I) and (II) directly or without using a conventionally known adhesive. The adhesive strength, especially the adhesive strength after bending fatigue is significantly superior to that obtained by joining and vulcanizing and integrating).

The rubber composite obtained by the method of the present invention is a rubber product in general, specifically, a rubber product for exploring the form of lamination of pneumatic tires, solid tires, crawlers / catavilers, rubber rolls, hoses and the like. Is useful as For example, nitrile-conjugated diene-based highly saturated copolymer rubber is used for the outer layer that requires high heat aging resistance, abrasion resistance and oil resistance, and diene elastomer is used for the inner layer from the viewpoint of cost and processability. Complexes such as old hoses and rubber rolls are highly practical.

(Preferred Embodiment of the Invention) The rubber adhesive composition of the present invention, that is, a vulcanizable rubber composition (I) containing an unvulcanized rubber and an organic peroxide vulcanizing agent, It is interposed between a vulcanizable rubber composition (II) containing a vulcanized rubber and a sulfur-based vulcanizing agent, and then both vulcanizable rubber compositions (I) and (II) are vulcanized and integrated. It is an adhesive used for producing a rubber composite by doing, and contains an ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber having an iodine value of 120 or less and an organic solvent as main components. A rubber adhesive composition containing neither a peroxide vulcanizing agent nor a sulfur-based vulcanizing agent;

The method for producing a rubber laminate of the present invention, that is, a vulcanizable rubber composition (I) containing an unvulcanized rubber and an organic peroxide vulcanizing agent, an unvulcanized rubber and sulfur A vulcanizable rubber composition (II) containing a vulcanizing agent is bonded to form a composite of the vulcanizable rubber compositions (I) and (II) with the vulcanizable rubber composition. A method for producing, wherein at least one of the above two vulcanizable rubber compositions (I) and (II) comprises an ethylenically unsaturated nitrile-conjugated diene highly saturated copolymer rubber having an iodine value of 120 or less and an organic solvent. And as a main component, a rubber adhesive composition containing neither an organic peroxide vulcanizing agent nor a sulfur-based vulcanizing agent is applied, so that the coating layer of the rubber adhesive composition intervenes. The above two vulcanizable rubber compositions (I) and (II) are joined, and then the both vulcanizable rubber compositions I), and summarized as follows preferred embodiments of the method for manufacturing a rubber composite, which comprises vulcanizing integrated (II).

(1) The rubber used in the organic peroxide vulcanizable rubber composition (I) is an ethylenically unsaturated nitrile-
It is a conjugated diene-based copolymer rubber or a hydride thereof. (2) The ethylenically unsaturated nitrile-conjugated diene-based copolymer rubber and the hydride thereof according to the above item (1) have a Mooney viscosity of 15 to 200, more preferably 30 to 100, and a bonded unsaturated nitrile unit content of It is 10 to 60% by weight, more preferably 15 to 45% by weight.

(3) The iodine value of the hydride of the ethylenically unsaturated nitrile-conjugated diene copolymer rubber according to the above (1) and (2) is 120 or less, more preferably 60 or less. (4) The ethylenically unsaturated nitrile-conjugated diene-based copolymer rubber of items (1) to (3) above is a copolymer of acrylonitrile, butadiene, and optionally a copolymerizable monomer.

(5) The organic peroxide vulcanizable rubber composition (I) containing the hydride of the ethylenically unsaturated nitrile-conjugated diene copolymer rubber as described in (1) to (3) above,
10 to 150 parts by weight, more preferably 10 to 100 parts by weight, of a metal salt of an α, β-ethylenically unsaturated carboxylic acid is included with respect to 100 parts by weight of the hydride. (6) The metal salt of α, β-ethylenically unsaturated carboxylic acid of the above item (5) is obtained by adding α, β-ethylenically unsaturated carboxylic acid to the hydride of the ethylenically unsaturated nitrile-conjugated diene copolymer rubber. And a metal compound are blended together to obtain i in the rubber composition.
It was produced by reacting in n situ.

(7) The molar ratio of the α, β-ethylenically unsaturated carboxylic acid of the above items (5) and (6) to the metal compound is 1:
0.5 to 1: 3.2, more preferably 1: 0.5 to 1:
2.5. (8) The α, β-ethylenically unsaturated carboxylic acid of the above (5), (6) and (7) is methacrylic acid, and the metal salt is a metal selected from zinc, aluminum, magnesium and calcium. It is salt.

(9) 0.2 to 10 parts by weight of the organic peroxide vulcanizable rubber composition (I) per 100 parts by weight of rubber,
More preferably, it contains 0.4 to 8 parts by weight of an organic peroxide vulcanizing agent. (10) The rubber used in the sulfur vulcanizable rubber composition (II) is selected from natural rubber, isoprene rubber, butadiene rubber and styrene-butadiene copolymer rubber.

(11) The sulfur vulcanizable rubber composition (II) contains 0.1 to 15 parts by weight, more preferably 0.3 to 10 parts by weight of a sulfur-based vulcanizing agent, and 0 to 100 parts by weight of rubber. .1
˜15 parts by weight, more preferably 0.3 to 10 parts by weight of vulcanization accelerator. (12) The ethylenically unsaturated nitrile-conjugated diene highly saturated copolymer rubber in the rubber adhesive composition has a Mooney viscosity of 1
5 to 200, more preferably 30 to 100, iodine value 1
It has 20 or less, more preferably 60 or less, and the content of bound unsaturated nitrile unit is 10 to 60% by weight, more preferably 15 to 45% by weight.

(13) The ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber in the rubber adhesive composition is a copolymer of acrylonitrile, butadiene, and optionally a copolymerizable monomer. It is a hydride. (14) The rubber adhesive composition further comprises 10 to 150 parts by weight, and more preferably 10 to 100 parts by weight of α, β-ethylenically unsaturated carboxylic acid, relative to 100 parts by weight of the highly saturated copolymer rubber. Contains metal salts.

(15) The metal salt of the α, β-ethylenically unsaturated carboxylic acid of the above item (14) is α, β-in the hydride of the ethylenically unsaturated nitrile-conjugated diene copolymer rubber.
Blending an ethylenically unsaturated carboxylic acid and a metal compound,
It is produced by reacting in situ in a rubber composition. (16) The molar ratio of the α, β-ethylenically unsaturated carboxylic acid of the preceding paragraphs (14) and (15) to the metal compound is 1: 0.5.
˜1: 3.2, more preferably 1: 0.5 to 1: 2.5
It is.

(17) (14), (15), (1)
The α, β-ethylenically unsaturated carboxylic acid of 6) is methacrylic acid, and the metal salt is a metal salt selected from zinc, aluminum, magnesium and calcium. (18) The organic solvent of the rubber adhesive composition is a ketone solvent,
More preferred is methyl ethyl ketone.

(19) The ratio of the ethylenically unsaturated nitrile-conjugated diene copolymer rubber to the solvent in the rubber adhesive composition is 3 to 50% by weight, more preferably 5 to 35% by weight. (20) The rubber adhesive composition further contains 5,000 parts by weight or less, more preferably 30 parts by weight, based on 100 parts by weight of the ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber.
˜5,000 parts by weight of chlorinated rubber adhesive or isocyanate adhesive.

(21) In the method for producing a rubber composite,
After coating the rubber adhesive composition on at least one of the vulcanizable rubber compositions (I) and (II), it is air-dried at room temperature for 30 minutes or more, and then a coating layer of the rubber adhesive composition is interposed. As described above, the two vulcanizable rubber compositions (I) and (II) are joined together,
Vulcanization is integrated at 120 to 200 ° C. (22) In the method for producing a rubber composite, a reinforcing layer made of a fiber material is interposed between both vulcanizable rubber compositions (I) and (II).

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

Claims (2)

[Claims] 1. A vulcanizable rubber composition (I) containing an unvulcanized rubber and an organic peroxide vulcanizing agent, and a vulcanizing composition containing an unvulcanized rubber and a sulfur-based vulcanizing agent. Rubber composition (I
An adhesive used for producing a rubber composite by interposing it between (I) and then vulcanizing and integrating both vulcanizable rubber compositions (I) and (II). It is characterized by containing the following ethylenically unsaturated nitrile-conjugated diene-based highly saturated copolymer rubber and an organic solvent as main components, and containing neither an organic peroxide vulcanizing agent nor a sulfur-based vulcanizing agent. And a rubber adhesive composition. 2. A vulcanizable rubber composition (I) containing an unvulcanized rubber and an organic peroxide vulcanizing agent, and a vulcanizing composition containing an unvulcanized rubber and a sulfur-based vulcanizing agent. Rubber composition (I
I) are joined to form the vulcanizable rubber compositions (I) and (I
A method for producing a composite of I) and the vulcanizable rubber composition, wherein at least one of the vulcanizable rubber compositions (I) and (II) has an iodine value of 120 or less. A rubber adhesive composition containing a saturated nitrile-conjugated diene-based highly saturated copolymer rubber and an organic solvent as main components and containing neither an organic peroxide vulcanizing agent nor a sulfur-based vulcanizing agent is applied. The two vulcanizable rubber compositions (I) and (II) are joined so that the coating layer of the rubber adhesive composition is present, and then the both vulcanizable rubber compositions (I) and (II) are joined. ) Is integrated by vulcanization.