JP6270435B2 - Rubber composition - Google Patents

Description

  The present invention relates to a rubber composition.

  A rubber composition containing solid rubber, liquid rubber, oil, etc. has excellent tackiness, and a crosslinked product obtained by crosslinking this has excellent adhesion to adherends, etc. It has been used as a sealing material, an adhesive for various members, and the like in various industrial applications such as automobile applications (see, for example, Patent Documents 1 to 4). When this rubber composition is used for vibration control, for example, it is common to add a filler or the like (see, for example, Patent Documents 3 and 4). When this rubber composition is used for applications such as the above-mentioned sealing material, adhesive, etc., each composition of the rubber composition is first mixed and stored in a sealed container or the like. Usually, the rubber composition is taken out of the rubber composition and used by crosslinking the rubber composition. Therefore, storage stability is required for the rubber composition used for such applications. In addition, the cross-linked product prepared from the rubber composition may be required to have heat resistance for its use, for example, for automobile use.

  Furthermore, in the case of a rubber composition containing a filler, if a large amount of filler is added, the viscosity increases, and the workability is affected. Therefore, a composition having a high vibration damping property is required with a smaller amount. ing.

JP 59-006272 A Japanese Patent Laid-Open No. 05-194922 JP 05-059345 A JP 2004-099651 A

  The present invention has been made in view of the above circumstances, and is excellent in storage stability and excellent in heat resistance and vibration damping performance of a crosslinked product obtained from this rubber composition, a sealing material, adhesion of various members, and the like. A rubber composition suitable for is provided.

  As a result of intensive studies by the present inventors, a rubber composition containing a specific solid rubber, a specific liquid diene rubber, a filler and an oil in a specific blending ratio is excellent in storage stability, and the rubber composition The cross-linked product obtained from No. 1 was found to be excellent in heat resistance and vibration damping performance, and completed the present invention.

That is, the present invention relates to [1] below.
[1] Selected from the group consisting of natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, ethylene propylene rubber and butyl rubber. 100 parts by mass of the rubber component consisting of 1 to 99% by mass of the solid rubber (A) and 99 to 1% by mass of the liquid diene rubber (B). It is a rubber composition containing parts by mass and 0.1 to 500 parts by mass of oil (D),
The liquid diene rubber (B) has a melt viscosity measured at 38 ° C. in the range of 0.1 to 10,000 Pa · s and is derived from a polymerization catalyst used for the production of the liquid diene rubber (B). A rubber composition having a residue amount in the range of 0 to 200 ppm in terms of metal.

  According to the present invention, a rubber composition not only excellent in storage stability but also excellent in heat resistance and vibration damping performance of a crosslinked product obtained from the composition can be obtained. Therefore, the rubber composition can be suitably used for adhesion of a sealing material and various members.

[Solid rubber (A)]
The solid rubber (A) used in the rubber composition of the present invention means a rubber that can be handled in a solid state, and the Mooney viscosity ML _{1 + 4} at 100 ° C. of the solid rubber (A) is usually in the range of 20 to 200. is there. The solid rubber (A) is natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, ethylene propylene rubber, and butyl rubber. Is at least one selected from the group consisting of

  The weight average molecular weight (Mw) of the solid rubber (A) is preferably 80,000 or more from the viewpoint of sufficiently exerting the properties of the resulting rubber composition, and is 100,000 to 3,000,000. More preferably within the range. In addition, the weight average molecular weight in this specification is the weight average molecular weight of polystyrene conversion calculated | required from the measurement of gel permeation chromatography (GPC).

  Examples of the natural rubber include natural rubber, high-purity natural rubber, epoxidized natural rubber, hydroxylated natural rubber, and hydrogenated natural rubber that are generally used in the tire industry such as SMR, SIR, and STR. And modified natural rubber such as grafted natural rubber. Among these, SMR20, STR20, and RSS # 3 are preferable from the viewpoint of little variation in quality and easy availability. These natural rubbers may be used alone or in combination of two or more.

  Examples of the polyisoprene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel. A lanthanoid rare earth metal catalyst such as triethylaluminum-organic acid neodymium-Lewis acid system; commercially available polyisoprene rubber polymerized using an organic alkali metal compound or the like can be used. Polyisoprene rubber polymerized with a Ziegler catalyst is preferred because of its high cis-isomer content. Moreover, you may use the polyisoprene rubber of the ultra high cis body content obtained using a lanthanoid type rare earth metal catalyst.

  The vinyl content of the polyisoprene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the flexibility of the rubber composition at low temperatures tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −20 ° C. or lower, and more preferably −30 ° C. or lower.

  The weight average molecular weight (Mw) of the polyisoprene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is in the above range, workability and mechanical strength are good.

  A part of the polyisoprene rubber is a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in its molecule, or an amino group-containing alkoxysilane. It may have a branched structure or a polar functional group.

  Examples of the polybutadiene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; A lanthanoid rare earth metal catalyst such as an aluminum-organic acid neodymium-Lewis acid system; a commercially available polybutadiene rubber polymerized using an organic alkali metal compound or the like can be used. Polybutadiene rubber polymerized with a Ziegler catalyst is preferred because of its high cis isomer content. Moreover, you may use the polybutadiene rubber of the ultra high cis body content obtained using a lanthanoid type rare earth metal catalyst.

  The vinyl content of the polybutadiene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. When the vinyl content exceeds 50% by mass, the flexibility of the rubber composition at low temperatures tends to deteriorate. The lower limit of the vinyl content is not particularly limited. The glass transition temperature varies depending on the vinyl content, but is preferably −40 ° C. or lower, and more preferably −50 ° C. or lower.

  The weight average molecular weight (Mw) of the polybutadiene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is in the above range, workability and mechanical strength are good.

  The polybutadiene rubber is partially branched by using a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group-containing alkoxysilane. It may have a structure or a polar functional group.

  As the styrene-butadiene copolymer rubber (hereinafter also referred to as SBR), an appropriate one can be used depending on the application, and specifically, a styrene content of 0.1 to 70% by mass is preferable. 5 to 50 mass% is more preferable, and 10 to 40 mass% is more preferable. Moreover, the thing whose vinyl content is 0.1-60 mass% is preferable, and a 0.1-55 mass% thing is more preferable.

  The weight average molecular weight (Mw) of SBR is preferably 100,000 to 2,500,000, more preferably 150,000 to 2,000,000, and 200,000 to 1,500,000. More preferably. When it is in the above range, both workability and mechanical strength can be achieved.

  The glass transition temperature determined by the differential thermal analysis method of SBR used in the present invention is preferably −95 to 0 ° C., more preferably −95 to −5 ° C. By setting the glass transition temperature in the above range, it is possible to suppress an increase in viscosity and to facilitate handling.

  As said SBR, the commercially available SBR obtained by copolymerizing styrene and butadiene can be used. There is no particular limitation on the production method of SBR, and any of an emulsion polymerization method, a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method can be used. Among these production methods, an emulsion polymerization method and a solution polymerization method are preferable. .

  Emulsion polymerization styrene-butadiene copolymer rubber (hereinafter also referred to as E-SBR) can be produced by a normal emulsion polymerization method, for example, a predetermined amount of styrene and butadiene monomers are emulsified and dispersed in the presence of an emulsifier, It can be obtained by emulsion polymerization with a radical polymerization initiator.

  As the emulsifier, for example, a long chain fatty acid salt or rosin acid salt having 10 or more carbon atoms is used. Specific examples include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid and stearic acid.

As the dispersant, water is usually used, and it may contain a water-soluble organic solvent such as methanol and ethanol as long as the stability during polymerization is not inhibited.
Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides, hydrogen peroxide, and the like.

  In order to adjust the molecular weight of the obtained E-SBR, a chain transfer agent can also be used. Examples of the chain transfer agent include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan; carbon tetrachloride, thioglycolic acid, diterpene, terpinolene, γ-terpinene, α-methylstyrene dimer and the like.

  Although the temperature of emulsion polymerization can be suitably selected according to the kind of radical polymerization initiator to be used, 0-100 degreeC is preferable normally and 0-60 degreeC is more preferable. The polymerization mode may be either continuous polymerization or batch polymerization. The polymerization reaction can be stopped by adding a polymerization terminator.

  Examples of the polymerization terminator include amine compounds such as isopropylhydroxylamine, diethylhydroxylamine, and hydroxylamine; quinone compounds such as hydroquinone and benzoquinone, and sodium nitrite.

  After termination of the polymerization reaction, an antioxidant may be added as necessary. After the polymerization reaction is stopped, unreacted monomers are removed from the obtained latex as necessary, and then a salt such as sodium chloride, calcium chloride, potassium chloride is used as a coagulant, and nitric acid, sulfuric acid, etc. The polymer can be recovered as crumbs by adding the acid and coagulating the polymer while adjusting the pH of the coagulation system to a predetermined value and then separating the dispersion solvent. E-SBR can be obtained by washing the crumb with water, followed by dehydration and drying with a band dryer or the like. In addition, at the time of coagulation, if necessary, a latex and an extending oil that has been made into an emulsified dispersion may be mixed and recovered as an oil-extended rubber.

  The solution-polymerized styrene-butadiene copolymer rubber (hereinafter also referred to as S-SBR) can be produced by an ordinary solution polymerization method. For example, an active metal capable of anionic polymerization in a solvent is used, and a polar compound is optionally formed. In the presence, styrene and butadiene are polymerized.

  Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene, And aromatic hydrocarbons such as toluene. These solvents are usually preferably used in a range where the monomer concentration is 1 to 50% by mass.

  Examples of the anion-polymerizable active metal include alkali metals such as lithium, sodium and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; lanthanoid rare earth metals such as lanthanum and neodymium . Among these active metals, alkali metals and alkaline earth metals are preferable, and alkali metals are more preferable. Further, among alkali metals, organic alkali metal compounds are more preferably used.

  Examples of the organic alkali metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1,4 -Polyfunctional organic lithium compounds such as dilithio-2-ethylcyclohexane and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is more preferable. The amount of the organic alkali metal compound used is appropriately determined depending on the required molecular weight of S-SBR.

The organic alkali metal compound can also be used as an organic alkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine, and dibenzylamine.
The polar compound is not particularly limited as long as it is usually used for adjusting the microstructure of the butadiene site and the distribution in the copolymer chain of styrene without deactivating the reaction in anionic polymerization. Examples include ether compounds such as dibutyl ether, tetrahydrofuran and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides and phosphine compounds.

  The temperature of the polymerization reaction is usually in the range of −80 to 150 ° C., preferably 0 to 100 ° C., more preferably 30 to 90 ° C. The polymerization mode may be either a batch type or a continuous type. In order to improve the random copolymerization of styrene and butadiene, styrene and butadiene are continuously or intermittently supplied into the reaction solution so that the composition ratio of styrene and butadiene in the polymerization system falls within a specific range. Is preferred.

  The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator. The polymerization solution after termination of the polymerization reaction can recover the target S-SBR by separating the solvent by direct drying, steam stripping or the like. In addition, before removing the solvent, the polymerization solution and the extending oil may be mixed in advance and recovered as an oil-extended rubber.

  As the SBR, a modified SBR having a functional group introduced may be used. Examples of the functional group include an amino group, an alkoxysilyl group, a hydroxyl group, an epoxy group, and a carboxyl group.

  As a method for producing the modified SBR, for example, before adding a polymerization terminator, tin tetrachloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, which can react with a polymerization active terminal, Coupling agents such as 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, 4,4′-bis (diethylamino) benzophenone, N-vinylpyrrolidone, etc. Or a method of adding other modifiers described in JP2011-132298A.

In this modified SBR, the position at which the functional group is introduced may be the polymer end or the side chain of the polymer main chain.
As the styrene-isoprene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, ethylene propylene rubber (EPM, EPDM, etc.) and butyl rubber, commercially available products can be used without particular limitation.

[Liquid diene rubber (B)]
The liquid diene rubber (B) used in the rubber composition of the present invention refers to a liquid diene polymer having a melt viscosity of 0.1 to 10,000 Pa · s measured at 38 ° C. Say.

  The liquid diene rubber (B) is preferably a polymer obtained by polymerizing the conjugated diene (b1) by the method described below. The rubber composition of the present invention exhibits excellent processability and adhesiveness by containing the liquid diene rubber (B).

  Examples of the conjugated diene (b1) include butadiene, isoprene, 2,3-dimethyl-butadiene, 2-phenyl-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, Examples include 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, and chloroprene. Of these conjugated dienes, butadiene and isoprene are preferred. These conjugated dienes may be used alone or in combination of two or more. When using 2 or more types together, the coupling | bonding form is not specifically limited, A perfect alternating, random, block, taper shape, or those combination may be sufficient.

  The liquid diene rubber (B) may be obtained by copolymerizing an aromatic vinyl compound (b2) in addition to the conjugated diene (b1). Examples of the aromatic vinyl compound (b2) include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, and 4-cyclohexylstyrene. 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, 1-vinylnaphthalene 2-vinylnaphthalene, vinylanthracene, N, N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, and divinylbenzene. Among these aromatic vinyl compounds, styrene, α-methylstyrene, and 4-methylstyrene are preferable.

  In the liquid diene rubber (B), the ratio of the aromatic vinyl compound (b2) unit to the total of the conjugated diene (b1) unit and the aromatic vinyl compound (b2) unit is the processability of the rubber composition of the present invention, and From an adhesive viewpoint, 50 mass% or less is preferable, 40 mass% or less is more preferable, and 30 mass% or less is still more preferable.

The liquid diene rubber (B) can be produced, for example, by a solution polymerization method.
As the solution polymerization method, a known method or a method according to a known method can be applied. For example, using a polymerization catalyst such as a Ziegler catalyst, a metallocene catalyst, an anion-polymerizable active metal or an active metal compound in a solvent, and a monomer containing a conjugated diene, if necessary, in the presence of a polar compound Polymerize the body.

  Examples of the anion-polymerizable active metal include alkali metals such as lithium, sodium and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium and barium; lanthanoid rare earth metals such as lanthanum and neodymium . Among the active metals capable of anion polymerization, alkali metals and alkaline earth metals are preferable, and alkali metals are more preferable.

  As the active metal compound capable of anionic polymerization, an organic alkali metal compound is preferable. Examples of the organic alkali metal compound include organic monolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, stilbenelithium; dilithiomethane, dilithionaphthalene Polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Of these organic alkali metal compounds, organic lithium compounds are preferred.

  The organic alkali metal compound can be used as an organic alkali metal amide by reacting with a secondary amine such as dibutylamine, dihexylamine and dibenzylamine.

  Although the usage-amount of the said polymerization catalyst can be suitably set according to the melt viscosity, molecular weight, etc. of liquid diene rubber (B), it is 0.01-3 normally with respect to 100 mass parts of all the monomers containing a conjugated diene. Used in parts by mass.

  Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; benzene Aromatic hydrocarbons such as toluene and xylene can be used.

  In the anionic polymerization, the polar compound is usually used to adjust the bonding form of the conjugated diene unit without deactivating the reaction. Examples of the polar compound include ether compounds such as dibutyl ether, tetrahydrofuran and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides and phosphine compounds. The polar compound is usually used in an amount of 0.01 to 1000 mol with respect to the polymerization catalyst.

  The temperature of solution polymerization is usually in the range of -80 to 150 ° C, preferably in the range of 0 to 100 ° C, more preferably in the range of 10 to 90 ° C. The polymerization mode may be either batch or continuous.

  The polymerization reaction can be stopped by adding a polymerization terminator. Examples of the polymerization terminator include alcohols such as methanol and isopropanol. The obtained polymerization reaction liquid is poured into a poor solvent such as methanol to precipitate the liquid diene rubber (B), or the polymerization reaction liquid is washed with water, separated and dried to obtain a liquid diene rubber (B ) Can be isolated.

  The liquid diene rubber (B) may be used as a modified liquid diene rubber modified with various functional groups. Examples of functional groups include amino groups, amide groups, imino groups, imidazole groups, urea groups, alkoxysilyl groups, hydroxyl groups, epoxy groups, ether groups, carboxyl groups, carbonyl groups, mercapto groups, isocyanate groups, nitrile groups, and acids. An anhydride group etc. are mentioned.

  As a method for producing a modified liquid diene rubber, for example, before adding a polymerization terminator, tin tetrachloride, dibutyltin chloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetra Coupling agents such as methoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, and 4,4′-bis (diethylamino) Polymerized terminal-modified compounds such as benzophenone, N-vinylpyrrolidone, N-methylpyrrolidone, 4-dimethylaminobenzylideneaniline, dimethylimidazolidinone, or other modified compounds described in JP2011-132298A are added, and Modified liquid diene rubber A method of adding the like to.

Further, a modified liquid diene rubber can be produced by grafting maleic anhydride or the like to the unmodified liquid diene rubber (B) after isolation.
In this modified diene polymer, the position at which the functional group is introduced may be the end of the polymer or the side chain of the polymer chain. The above functional groups can be used alone or in combination of two or more. The above modifier is preferably used in an amount of 0.01 to 100 molar equivalents relative to the organic alkali metal compound.

  The liquid diene rubber (B) is characterized in that the amount of catalyst residue derived from the polymerization catalyst used for its production is in the range of 0 to 200 ppm in terms of metal. For example, when an organic alkali metal compound such as an organic lithium compound is used as a polymerization catalyst for producing the liquid diene rubber (B), the metal serving as a reference for the amount of catalyst residue is an alkali metal such as lithium. . When the amount of the catalyst residue is within the above range, the rubber composition of the present invention is excellent in storage stability, and further, the heat resistance and vibration damping performance of the crosslinked product obtained from the rubber composition of the present invention can be improved. The amount of catalyst residue derived from the polymerization catalyst used for the production of the liquid diene rubber (B) is preferably 0 to 150 ppm, more preferably 0 to 100 ppm in terms of metal. The amount of catalyst residue can be measured by using, for example, a polarized Zeeman atomic absorption spectrophotometer.

  Examples of a method of setting the amount of catalyst residue of the liquid diene rubber to such a specific amount include a method of purifying the liquid diene rubber (B) after polymerization and sufficiently removing the catalyst residue. As a purification method, washing with water or warm water, an organic solvent typified by methanol, acetone or the like or supercritical fluid carbon dioxide is preferable. The number of washings is preferably 1 to 20 times and more preferably 1 to 10 times from the economical viewpoint. Moreover, as washing | cleaning temperature, 20-100 degreeC is preferable and 40-90 degreeC is more preferable. Also, by removing the impurities that inhibit the polymerization by distillation or adsorbent before the polymerization reaction, and performing the polymerization after increasing the purity of the monomer, the amount of polymerization catalyst required can be reduced, The amount of catalyst residue can be reduced.

  The melt viscosity of the liquid diene rubber (B) measured at 38 ° C. is in the range of 0.1 to 10,000 Pa · s, preferably in the range of 0.5 to 7,000 Pa · s, more preferably 0. The range is from 5 to 5,000 Pa · s, more preferably from 0.5 to 3,000 Pa · s. When the melt viscosity of the liquid diene rubber (B) is within the above range, the processability and adhesiveness of the resulting rubber composition tend to be improved. In the present invention, the melt viscosity of the liquid diene rubber (B) is a value determined by the method described in Examples described later.

  The weight average molecular weight (Mw) of the liquid diene rubber (B) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, still more preferably 3,000 to 150,000, and 3,000. ~ 90,000 is even more preferred. When the Mw of the liquid diene rubber (B) is within the above range, the processability and adhesiveness of the rubber composition of the present invention tend to be improved.

In the present invention, two or more kinds of liquid diene rubbers (B) having different Mw may be used in combination.
The molecular weight distribution (Mw / Mn) of the liquid diene rubber (B) is preferably 1.0 to 8.0, more preferably 1.0 to 5.0, and still more preferably 1.0 to 3.0. It is more preferable that Mw / Mn is within the above range, since the dispersion of the viscosity of the obtained polymer (B) is small.

  The glass transition temperature (Tg) of the liquid diene rubber (B) is the vinyl content of units derived from the conjugated diene (b1), the type of conjugated diene (b1), and the content of units derived from monomers other than the conjugated diene. However, it is preferably −100 to 30 ° C., more preferably −100 to 20 ° C., and still more preferably −100 to 10 ° C. When Tg is in the above range, for example, the processability, adhesiveness, and vibration damping properties of the rubber composition are improved. The vinyl content of the liquid diene rubber (B) is preferably 99% by mass or less, and more preferably 90% by mass or less.

  In the rubber composition of the present invention, the rubber component is composed of the solid rubber (A) and the liquid diene rubber (B). The rubber component is composed of 1 to 99% by mass of solid rubber (A) and 99 to 1% by mass of liquid diene rubber (B), preferably 5 to 99% by mass of solid rubber (A) and liquid. The diene rubber (B) is composed of 95 to 1% by mass, more preferably 10 to 90% by mass of the solid rubber (A), and 90 to 10% by mass of the liquid diene rubber (B). When the blending ratio of the solid rubber (A) and the liquid diene rubber (B) is in the above range, the processability, heat resistance and vibration damping properties of the rubber composition are improved.

[Filler (C)]
The filler (C) used in the rubber composition of the present invention is blended for the purpose of improving mechanical strength, improving physical properties such as heat resistance or weather resistance, adjusting hardness, and increasing the amount of rubber. Examples of the filler include calcium carbonate, calcium oxide, magnesium hydroxide, magnesium oxide, magnesium carbonate, aluminum hydroxide, barium sulfate, barium oxide, titanium oxide, iron oxide, zinc oxide, zinc carbonate, wax stone clay, and kaolin. Clay such as clay and calcined clay, mica, diatomaceous earth, carbon black, silica, glass fiber, carbon fiber, fibrous filler, inorganic filler such as glass balloon, crosslinked polyester, polystyrene, styrene-acrylic copolymer resin, or urea Examples thereof include resin particles formed from a resin such as a resin, synthetic fibers, and natural fibers.

  In addition, when the said filler is a particulate form, according to the desired physical property etc., the shape of the particle | grain can take various shapes, such as a spherical shape. Further, when the filler is in the form of particles, it may be solid particles or hollow particles depending on the desired physical properties, etc., and may be core-shell type particles formed of a plurality of materials. May be. Further, these fillers may be subjected to surface treatment with various compounds such as fatty acids, resin acids, fatty acid esters, silane coupling agents and the like.

  Among these fillers (C), calcium carbonate, carbon black, and silica are preferable from the viewpoints of the reinforcing property, cost, ease of handling, and the like of the obtained rubber composition and its crosslinked product, and calcium carbonate and carbon black are more preferable. preferable. These fillers (C) may be used individually by 1 type, and may use 2 or more types together.

  In the rubber composition of the present invention, the filler (C) content relative to 100 parts by mass of the rubber component consisting of 1 to 99% by mass of the solid rubber (A) and 99 to 1% by mass of the liquid diene rubber (B) is 0.00. 1 to 1500 parts by mass, preferably 1 to 1400 parts by mass, and more preferably 5 to 1300 parts by mass. When the content of the filler (C) is within the above range, the processability and adhesiveness of the rubber composition are good.

[Oil (D)]
The oil (D) used in the rubber composition of the present invention is mainly intended to improve the processability of the rubber composition of the present invention and the dispersibility of other compounding agents, and the properties of the rubber composition are within a desired range. To be added. Examples of the oil (D) include mineral oil, vegetable oil, and synthetic oil.

  Examples of the mineral oil include paraffinic oil, naphthenic oil, and aromatic oil. Examples of vegetable oils include castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, and the like. Examples of synthetic oils include ethylene / α-olefin oligomers and liquid paraffin.

Among these oils (D), paraffinic oil, naphthenic oil, and aromatic oil are preferable, and naphthenic oil is more preferable.
These oils (D) may be used alone or in combination of two or more.

  In the rubber composition of the present invention, the content of the oil (D) with respect to 100 parts by mass of the rubber component consisting of 1 to 99% by mass of the solid rubber (A) and 99 to 1% by mass of the liquid diene rubber (B) is 0.00. 1 to 500 parts by mass, preferably 1 to 450 parts by mass, and more preferably 5 to 400 parts by mass. When the content of oil (D) is within the above range, the processability and adhesiveness of the rubber composition are good.

[Other ingredients]
The rubber composition of the present invention may further contain a crosslinking agent. Examples of the crosslinking agent include sulfur, sulfur compounds, oxygen, organic peroxides, phenol resins, amino resins, quinones and quinonedioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides, and organic metals. Examples thereof include halides and silane compounds. Examples of the sulfur compound include morpholine disulfide and alkylphenol disulfide. Organic peroxides include cyclohexanone peroxide, methyl acetoacetate peroxide, tert-butyl peroxyisobutyrate, tert-butyl peroxybenzoate, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-tert-butyl Examples thereof include peroxide and 1,3-bis (tert-butylperoxyisopropyl) benzene. These crosslinking agents may be used alone or in combination of two or more. From the viewpoint of the mechanical properties of the crosslinked product, the crosslinking agent is usually 0 with respect to 100 parts by mass of the rubber component consisting of 1 to 99% by mass of the solid rubber (A) and 99 to 1% by mass of the liquid diene rubber (B). 0.1 to 10 parts by mass, preferably 0.5 to 10 parts by mass, more preferably 0.8 to 10 parts by mass.

  The rubber composition of the present invention may further contain a vulcanization accelerator when, for example, sulfur, a sulfur compound or the like is contained as a crosslinking agent. Examples of vulcanization accelerators include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds, aldehyde-ammonia compounds, and imidazoline compounds. Examples thereof include compounds and xanthate compounds. These vulcanization accelerators may be used alone or in combination of two or more. The vulcanization accelerator is usually 0.1 to 15 parts by mass with respect to 100 parts by mass of the rubber component consisting of 1 to 99% by mass of the solid rubber (A) and 99 to 1% by mass of the liquid diene rubber (B). Preferably 0.1-10 mass parts is contained.

  The rubber composition of the present invention may further contain a vulcanization aid when, for example, sulfur, a sulfur compound or the like is contained as a crosslinking agent. Examples of the vulcanization aid include fatty acids such as stearic acid, metal oxides such as zinc white, and fatty acid metal salts such as zinc stearate. These vulcanization aids may be used alone or in combination of two or more. The vulcanization aid is usually 0.1 to 15 parts by weight, preferably 0, based on the rubber component consisting of 1 to 99% by weight of the solid rubber (A) and 99 to 1% by weight of the liquid diene rubber (B). 0.5 to 10 parts by mass is contained.

  The rubber composition of the present invention is intended to improve processability, fluidity and the like within a range not impairing the effects of the present invention, and an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin, a C9 resin as required. Further, it may contain a tackifying resin such as a rosin resin, a coumarone / indene resin, and a phenol resin.

  Further, the rubber composition of the present invention is an anti-aging agent, an antioxidant, a light stable, if necessary, for the purpose of improving the weather resistance, heat resistance, oxidation resistance, etc. within the range not inhibiting the effects of the present invention. Agent, scorch inhibitor, functional group-containing compound, wax, lubricant, plasticizer, processing aid, pigment, dye, dye, other colorant, flame retardant, antistatic agent, matting agent, antiblocking agent, UV absorber In addition, additives such as mold release agents, foaming agents, antibacterial agents, antifungal agents, fragrances, dispersants and solvents may be further contained.

Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, lactone compounds, hydroxyl compounds, and the like.
Examples of the antiaging agent include amine-ketone compounds, imidazole compounds, amine compounds, phenolic compounds, sulfur compounds, and phosphorus compounds.

  A functional group-containing compound may be added in order to improve the adhesiveness and adhesion between the rubber composition and the adherend. Examples of the functional group-containing compound include N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, functional group-containing alkoxysilane such as γ-glycidoxypropyltrimethoxysilane, 2-hydroxyethylacryloyl phosphate, Examples thereof include functional group-containing acrylates and methacrylates such as 2-hydroxyethylmethacryloyl phosphate, nitrogen-containing acrylate, and nitrogen-containing methacrylate. From the viewpoint of adhesiveness and adhesion, the functional group is preferably an epoxy group.

  Examples of the pigment include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride and sulfate; organic pigments such as azo pigments and copper phthalocyanine pigments. It is done.

Examples of the antistatic agent include hydrophilic compounds such as quaternary ammonium salts, polyglycols, and ethylene oxide derivatives.
Examples of the flame retardant include chloroalkyl phosphate, dimethyl / methylphosphonate, bromine / phosphorus compound, ammonium polyphosphate, neopentyl bromide-polyether, and brominated polyether.
These additives may be used alone or in combination of two or more.

[Method for producing rubber composition]
The manufacturing method of the rubber composition of this invention will not be specifically limited if said each component can be mixed uniformly. As an apparatus used for manufacturing the rubber composition, for example, a tangential or meshing type closed kneader such as a kneader ruder, a brabender, a banbury mixer, an internal mixer, a single screw extruder, a twin screw extruder, a mixing roll, etc. , And rollers. The mixing is preferably performed under reduced pressure or in a nitrogen atmosphere from the viewpoint of preventing air bubbles from being mixed in the composition during mixing. Thus, the rubber composition of the present invention obtained by uniformly dispersing each component is preferably stored in a sealed container or the like until use.

  After apply | coating the rubber composition of this invention to base materials, such as an oil surface steel plate, as needed, a crosslinked material can be obtained by bridge | crosslinking this. Although the crosslinking conditions of a rubber composition can be suitably set according to the use etc., a crosslinked material can be manufactured by performing a crosslinking reaction for 10 to 60 minutes, for example in the temperature range of 130-250 degreeC. For example, when the rubber composition of the present invention is used in an automobile production line, for example, the rubber composition of the present invention is applied to desired portions of various members (for example, gaps between flanges of a plurality of frame members). Then, when performing baking drying in the electrodeposition coating process of the vehicle body, a crosslinked product can be formed at a desired site by crosslinking with the generated heat.

  The crosslinked product obtained from the rubber composition of the present invention is excellent not only in storage stability and heat resistance but also in vibration damping performance. Therefore, it can be used for various industrial products and the like, and in particular, it can be suitably used for automotive parts or automotive parts such as engine parts, suspension systems, drive systems, steering systems, and floors.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Each component used in the examples and comparative examples is as follows.
<Solid rubber (A)>
Polybutadiene rubber (BR) Diene NF35R (Asahi Kasei Co., Ltd.)
<Liquid diene rubber (B)>
Liquid diene rubbers of Production Examples 1 to 12 described later <Filler (C)>
Calcium carbonate Shiraka Hana CCR
<Oil (D)>
Naphthenic oil SUNTHENE 250 (manufactured by Nippon Sun Oil Co., Ltd.)
<Optional component>
・ Sulfuric crosslinker sulfur (fine powder sulfur 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.)
・ Vulcanization accelerator Vulcanization accelerator (1): Noxeller DM (Ouchi Shinsei Chemical Co., Ltd.)
Vulcanization accelerator (2): Noxeller BG (Ouchi Shinsei Chemical Co., Ltd.)
・ Vulcanization aid stearic acid: LUNAC S-20 (manufactured by Kao Corporation)
Zinc flower: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.)
Other anti-aging agent: NOCRACK NS-6 (Ouchi Shinsei Chemical Co., Ltd.)

Production Example 1: Production of liquid polyisoprene (B-1) A sufficiently dried pressure vessel was replaced with nitrogen, and 600 g of hexane and 44.9 g of n-butyllithium (17% by mass hexane solution) were charged into this pressure vessel. After the temperature was raised to 70 ° C., 2050 g of isoprene was added and polymerized for 1 hour while controlling the polymerization temperature to be 70 ° C. under stirring conditions (polymerization step). Thereafter, methanol was added to stop the polymerization reaction, and a polymerization solution (2695 g) was obtained. To this polymerization solution in a pressure vessel, warm water at 60 ° C. was added (so that the polymerization solution / warm water volume ratio = 2/1), stirred for 30 minutes, and allowed to stand for 30 minutes. After confirming that the phases were separated, the aqueous phase was removed (hereinafter, this operation is referred to as a washing operation (1)). This washing operation (1) was further repeated, and the washing operation (1) was performed four times in total. The polymer solution that had undergone the washing operation was vacuum-dried at 70 ° C. for 12 hours to obtain liquid polyisoprene (B-1). Table 1 shows the physical properties of the obtained liquid polyisoprene (B-1).

Production Example 2: Production of liquid polyisoprene (B-2) Liquid polyisoprene (B-2) was polymerized, washed and dried in the same manner as in Production Example 1 except that the washing operation (1) was repeated three times. Got. Table 1 shows the physical properties of the obtained liquid polyisoprene (B-2).

Production Example 3: Production of liquid polyisoprene (B-3) A sufficiently dried pressure vessel was replaced with nitrogen, and 600 g of hexane and 13.9 g of n-butyllithium (17% by mass hexane solution) were charged into this pressure vessel. After the temperature was raised to 70 ° C., 1370 g of isoprene was added and polymerized for 1 hour while controlling the polymerization temperature to be 70 ° C. under stirring conditions (polymerization step). Thereafter, methanol was added to stop the polymerization reaction, and a polymerization solution (1980 g) was obtained. Thereafter, the washing operation (1) described in Production Example 1 was performed three times. The polymer solution that had undergone the washing operation was vacuum-dried at 70 ° C. for 12 hours to obtain liquid polyisoprene (B-3). Table 1 shows the physical properties of the obtained liquid polyisoprene (B-3).

Production Example 4: Production of liquid polyisoprene (B-4) Liquid polyisoprene (B-4) was polymerized, washed and dried in the same manner as in Production Example 3 except that the washing operation (1) was repeated twice. Got. Table 1 shows the physical properties of the obtained liquid polyisoprene (B-4).

Production Example 5: Production of Liquid Butadiene-Isoprene Block Copolymer (B-5) A sufficiently dried pressure vessel was replaced with nitrogen, and 600 g of hexane and n-butyllithium (17% by mass hexane solution) were placed in this pressure vessel. After charging 13.4 g and raising the temperature to 70 ° C., 810 g of butadiene was added for polymerization for 1 hour while controlling the polymerization temperature to be 70 ° C. under stirring conditions, and then 90 g of isoprene was further added. Polymerization was performed for 1 hour (polymerization step). Thereafter, methanol was added to stop the polymerization reaction to obtain a polymerization solution (1513 g). Thereafter, the washing operation (1) described in Production Example 1 was performed 4 times. The polymer solution after the washing operation was vacuum dried at 70 ° C. for 12 hours to obtain a liquid butadiene-isoprene block copolymer (B-5). Table 1 shows the physical properties of the obtained liquid butadiene-isoprene block copolymer (B-5).

Production Example 6: Production of Liquid Butadiene-Isoprene Block Copolymer (B-6) Polymerization, washing operation and drying were conducted in the same manner as in Production Example 5 except that the washing operation (1) was repeated three times. An isoprene block copolymer (B-6) was obtained. Table 1 shows the physical properties of the obtained liquid butadiene-isoprene block copolymer (B-6).

Production Example 7 Production of Liquid Styrene-Butadiene Random Copolymer (B-7) A sufficiently dried pressure vessel was replaced with nitrogen, and 600 g of cyclohexane and sec-butyl lithium (10.5 mass% cyclohexane) were placed in this pressure vessel. Solution) 38 g and tetramethylenediamine 3.2 g were charged and heated to 50 ° C., and then the butadiene (a) and styrene (b) were adjusted in advance while controlling the polymerization temperature to 50 ° C. under stirring conditions. 425 g of butadiene (a) and styrene (b) (170 g) were added in a cylinder and polymerized for 1 hour (polymerization step). Thereafter, methanol was added to stop the polymerization reaction to obtain a polymerization solution (1066 g). Thereafter, the washing operation (1) described in Production Example 1 was performed 4 times. The polymer solution after the washing operation was vacuum-dried at 70 ° C. for 12 hours to obtain a liquid styrene-butadiene random copolymer (B-7). Table 1 shows the physical properties of the obtained liquid styrene-butadiene random copolymer (B-7).

Production Example 8: Production of Liquid Styrene-Butadiene Random Copolymer (B-8) The same polymerization, washing operation and drying as in Production Example 7 were carried out except that the washing operation (1) was carried out three times. A butadiene random copolymer (B-8) was obtained. Table 1 shows the physical properties of the obtained liquid styrene-butadiene random copolymer (B-8).

Production Example 9 Production of Liquid Polyisoprene (B-9) Polymerization was carried out in the same polymerization step as in Production Example 1, and methanol was added to the polymerization reaction solution to stop the polymerization reaction. Next, after removing the polymerization solution from the pressure vessel, the pressure vessel was continuously used without washing, and a second polymerization was carried out in the same polymerization step as in Production Example 1 except that 1190 g of isoprene was used. Without washing the polymerization solution obtained by the second polymerization, it was vacuum-dried at 70 ° C. for 12 hours to obtain liquid polyisoprene (B-9). Table 1 shows the physical properties of the obtained liquid polyisoprene (B-9).

Production Example 10 Production of Liquid Polyisoprene (B-10) Polymerization was carried out in the same polymerization step as in Production Example 3, and methanol was added to the polymerization reaction solution to stop the polymerization reaction. Next, after removing the polymerization solution from the pressure-resistant container, the pressure-resistant container was continuously used without washing, and polymerization was carried out in the same polymerization step as in Production Example 3 except that 359 g of isoprene was used. Without washing the polymerization solution obtained by the second polymerization, it was vacuum-dried at 70 ° C. for 12 hours to obtain liquid polyisoprene (B-10). Table 1 shows the physical properties of the obtained liquid polyisoprene (B-10).

Production Example 11 Production of Liquid Butadiene-Isoprene Block Copolymer (B-11) Polymerization was carried out in the same polymerization step as in Production Example 5, and methanol was added to the polymerization reaction solution to stop the polymerization reaction. Next, after removing the polymerization solution from the pressure vessel, the pressure vessel was continuously used without washing, and polymerization was carried out in the same polymerization step as in Production Example 5 except that 288 g of butadiene and 32 g of isoprene were used. Without washing the polymerization solution obtained in the second polymerization, it was vacuum dried at 70 ° C. for 12 hours to obtain a liquid butadiene-isoprene block copolymer (B-11). Table 1 shows the physical properties of the obtained liquid butadiene-isoprene block copolymer (B-11).

Production Example 12: Production of Liquid Styrene-Butadiene Random Copolymer (B-12) Polymerization was carried out in the same polymerization step as in Production Example 7, and methanol was added to the polymerization reaction solution to stop the polymerization reaction. Next, after the polymerization solution is taken out from the pressure vessel, the pressure vessel is continuously used without washing, and a mixture of butadiene (a) and styrene (b) prepared in advance (204 g of butadiene (a) and 136 g of styrene (b) is obtained. The second polymerization was carried out in the same polymerization step as in Production Example 7 except that 340 g was used. Without washing the polymerization solution obtained by the second polymerization, it was vacuum-dried at 70 ° C. for 12 hours to obtain a liquid styrene-butadiene random copolymer (B-12). Table 1 shows the physical properties of the obtained liquid styrene-butadiene random copolymer (B-12).
In addition, the measuring method of the weight average molecular weight (Mw), melt viscosity, and catalyst residue amount of liquid diene rubber (B) is as follows.

(Measurement method of weight average molecular weight)
The Mw of the liquid diene rubber (B) was determined by GPC (gel permeation chromatography) as a standard polystyrene equivalent molecular weight. The measuring apparatus and conditions are as follows.
・ Device: GPC device “GPC8020” manufactured by Tosoh Corporation
Separation column: “TSKgel G4000HXL” manufactured by Tosoh Corporation
Detector: “RI-8020” manufactured by Tosoh Corporation
・ Eluent: Tetrahydrofuran ・ Eluent flow rate: 1.0 ml / min ・ Sample concentration: 5 mg / 10 ml
-Column temperature: 40 ° C

(Measuring method of melt viscosity)
The melt viscosity of the liquid diene rubber (B) at 38 ° C. was measured with a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).

(Amount of catalyst residue)
1) Preparation of sample solution Sample solution: 0.5 to 5.0 g of the liquid diene rubber (B) obtained in Production Examples 1 to 12 was accurately weighed and pretreated with a small amount of concentrated sulfuric acid, and then platinum. It was put in a dish and gradually heated with an electric stove to be incinerated. After cooling, 5 mL of 20% (v / v) hydrochloric acid was added, and ultrapure water was added to make 50 mL, which was used as a sample solution.

Standard solution (a) (blank): Ultrapure water was added to 5 mL of 20% (v / v) hydrochloric acid to make 50 mL.
Standard solution (b) (Li: 0.1 ppm (w / v)): 20 mL (v / v) hydrochloric acid 5 mL and lithium standard solution (1000 ppm (w / v)) 0.005 mL were accurately taken, and ultrapure water was added. Add to 50 mL.

  Standard solution (c) (Li: 2.0 ppm (w / v)): 20 mL (v / v) hydrochloric acid 5 mL and lithium standard solution (1000 ppm (w / v)) 0.10 mL were accurately taken, and ultrapure water was added. Add to 50 mL.

  Standard solution (d) (Li: 5.0 ppm (w / v)): 20% (v / v) hydrochloric acid 5 mL and lithium standard solution (1000 ppm (w / v)) 0.25 mL were accurately taken, and ultrapure water was added. Add to 50 mL.

2) Measuring method It was determined by a calibration curve method using an atomic absorption photometric flame method (frame: air-acetylene (wavelength: 670.8 nm)). The absorbance is measured in the order of the standard solutions (a), (b), (c) and (d), and a calibration curve is prepared. Next, the absorbance of the sample solution was measured, and the amount of lithium catalyst residue per 1 g of the liquid diene rubber (B) was calculated according to the following formula. A polarization Zeeman atomic absorption spectrophotometer (model “Z-5010”, manufactured by Hitachi High-Technologies Corporation) was used for the measurement of absorbance. A product manufactured by Wako Pure Chemical Industries, Ltd. was used as a standard lithium solution for atomic absorption.
Catalyst residue amount (lithium: ppm (w / v)) = (C / sampled amount (g)) × 50
(However, C = Lithium concentration in the measuring solution (ppm (w / v)))

(Examples 1-8 and Comparative Examples 1-4)
Solid rubber (A), liquid diene rubbers (B-1) to (B-12), filler (C), oil (D), stearic acid, zinc white, and antiaging agent are blended in the proportions shown in Table 2. And kneaded. Subsequently, sulfur, a vulcanization accelerator (1), and a vulcanization accelerator (2) were added in the ratio shown in Table 2, and it knead | mixed, and the rubber composition of this invention was obtained. The obtained rubber composition was evaluated by the following method. The results are shown in Table 2.
In addition, the measuring method of each evaluation is as follows.

(1) tan δ (25 ° C)
A required amount of the rubber composition was taken on a Teflon sheet, sandwiched between Teflon sheets with a spacer having a thickness of 2 mm, and pressed at a press molding machine heated to 150 ° C. for 30 minutes to obtain a sheet-like cured product having a thickness of 2 mm. . This was cut into a strip shape having a width of 10 mm * length of 60 mm, and using a viscoelasticity measuring device (EPLEXOR500N manufactured by GAB0) at a temperature range of -20 to 80 ° C., a rate of temperature increase of 2 ° C./min, a static strain of 5% The tan δ at 25 ° C. was measured by measuring under conditions of a dynamic strain of 1% and a frequency of 10 Hz.
The numerical value of each Example and Comparative Example is a relative value when the value of Example 1 is set to 100. In addition, the damping performance of a rubber composition is so favorable that a numerical value is large.

(2) Heat resistance: shear adhesion retention rate The shear adhesion was measured according to JIS K 6850. The test material used was a SPCC-SD steel plate specified in JIS G 3141, with a thickness of 1 mm coated with a rust inhibitor. The rubber composition was applied to a steel sheet so as to have a thickness of 1 mm, heated at 150 ° C. for 30 minutes, and cured to obtain a test piece. The shear strength after each of the obtained test pieces was heat-treated under the following conditions was measured, and the shear strength retention rate was determined by the following formula. The tensile speed for measuring the shear adhesive force was 50 mm / min.
Shear adhesive strength retention (%) = [shear adhesive strength a] / [shear adhesive strength b] × 100
Shear adhesive strength a: Measured after standing for 24 hours under conditions of 23 ° C. and 50% RH.
Shear adhesive strength b: measured after standing for 30 minutes at 210 ° C.

(3) Storage stability The obtained rubber composition was filled in a cartridge gun and left at 40 ° C. for 2 weeks. After leaving, it was marked with ○ when application was possible using a cartridge gun, and × when application was impossible.

  When comparing Examples 1 and 2 and Comparative Example 1, Examples 3 and 4 and Comparative Example 2, Examples 5 and 6 and Comparative Example 3, Examples 7 and 8 and Comparative Example 4, respectively, the same molecular weight and composition were obtained. When the liquid diene rubber (B) is used, a rubber composition having excellent storage stability and excellent heat resistance and vibration damping performance after cross-linking can be obtained by using one having a smaller amount of catalyst residue. I understand that.

  The rubber composition of the present invention is excellent in storage stability, and the cross-linked product obtained from this rubber composition has high heat resistance and excellent vibration damping performance. Therefore, the rubber composition is suitably used for adhesion of sealing materials and various members. It is useful for various industrial products such as automobiles and daily necessities.

Claims (4)

At least one selected from the group consisting of natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, ethylene propylene rubber and butyl rubber. 0.1 to 1500 parts by mass of filler (C) with respect to 100 parts by mass of the rubber component consisting of 1 to 99% by mass of the seed solid rubber (A) and 99 to 1% by mass of the liquid diene rubber (B), And a rubber composition containing 0.1 to 500 parts by mass of oil (D),
The liquid diene rubber (B) has a melt viscosity measured at 38 ° C. in the range of 0.1 to 5,000 Pa · s and is derived from the polymerization catalyst used for the production of the liquid diene rubber (B). A rubber composition having an amount of catalyst residue in the range of 0 to 150 ppm in terms of metal.   The rubber composition according to claim 1, wherein the liquid diene rubber (B) is an unmodified liquid diene rubber. Melt viscosity measured at 38 ° C. of liquid diene rubber (B) is in the range of 74~2,080Pa · s, the rubber composition according to claim 1 or 2.   The rubber composition according to any one of claims 1 to 3, wherein the liquid diene rubber (B) has a weight average molecular weight (Mw) of 1,000 to 500,000.