JP6218560B2 - 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 is 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). In addition, in order to improve the adhesion of the rubber composition to metal or the like, a method of using a modified liquid rubber modified with a functional group as a liquid rubber is known (see, for example, Patent Documents 2 and 4). . When such a rubber composition is used for applications such as the above-mentioned sealing material, adhesive, etc., each component of the rubber composition is first mixed and stored in a sealed container or the like. Usually, a rubber composition is applied to a substrate or the like from a container using a cartridge gun or the like, and the rubber composition is used by crosslinking. Therefore, it is desired that the rubber composition used for such applications is excellent in applicability and thread cut-off property when applied with a cartridge gun or the like. In addition, considering that these rubber compositions are suitably used for sealing metallic materials, bonding metallic members, etc. in industrial product applications such as automobile members, it is possible to further improve the rubber composition. Metal corrosion resistance is desired.

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-mentioned circumstances, and is excellent in workability, and in addition, a sealing material excellent in adhesiveness and metal corrosion resistance of a cross-linked product obtained from this rubber composition, and adhesion of various members. A suitable rubber composition is provided.

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

That is, the present invention relates to the following [1] and [2].
[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. The filler (C) 0.1 to 100 parts by mass of the rubber component consisting of 1 to 99% by mass of the solid rubber (A) and the modified liquid diene rubber (B) 99 to 1% by mass. A rubber composition containing 1500 parts by mass and 0.1 to 500 parts by mass of oil (D), wherein the modified liquid diene rubber (B) satisfies the following requirements (I) to (III) object.
(I) The melt viscosity of the modified liquid diene rubber (B) measured at 38 ° C. is in the range of 0.1 to 10,000 Pa · s.
(II) When measured by gel permeation chromatography (GPC), the maximum peak molecular weight (Mt) is in the range of 3,000 to 120,000, and the total area derived from the polymer in the resulting GPC chromatogram is 100%. As a result, the proportion of the polymer having a molecular weight in the region of Mt × 1.45 or more is 0 to 20%.
(III) The modified liquid diene rubber (B) is obtained by adding a modified compound to the liquid diene rubber (B ′), and the addition reaction rate of the modified compound is 40 to 100 mol%.

  [2] The rubber composition according to [1], wherein the modifying compound added to the liquid diene rubber (B ′) is maleic anhydride.

  According to the present invention, a rubber composition not only excellent in workability but also excellent in adhesion and metal corrosion resistance of a crosslinked product obtained from the composition can be obtained. Therefore, the rubber composition of the present invention can be suitably used for adhesion of sealing materials 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 at 20 ° C., and the Mooney viscosity ML _{1 + 4} at 100 ° C. of the solid rubber (A) is usually 20 to 200. It is in the range. The solid rubber (A) includes natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, ethylene propylene rubber, and It is at least one selected from the group consisting of butyl rubber.

  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 a number average molecular weight in terms of polystyrene measured by 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 commercially available polyisoprene rubber polymerized using a lanthanoid rare earth metal catalyst such as triethylaluminum-organic acid neodymium-Lewis acid system or the like, or an organic alkali metal compound in the same manner as S-SBR 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.

  If the polyisoprene rubber is within a range not impairing the effects of the present invention, a part thereof is a polyfunctional modifier, such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an amino group. It may have a branched structure or a polar functional group by using a modifier such as a contained alkoxysilane.

  Examples of the polybutadiene rubber include Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; Commercially available polybutadiene rubber polymerized with a lanthanoid rare earth metal catalyst such as an aluminum-organic acid neodymium-Lewis acid type or the like, or an organic alkali metal compound in the same manner as S-SBR 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.

  If the polybutadiene rubber is within a range not impairing the effects of the present invention, a part thereof is a polyfunctional modifier, for example, tin tetrachloride, silicon tetrachloride, alkoxysilane having an epoxy group in the molecule, or amino group-containing By using a modifier such as alkoxysilane, it may have a branched 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 it is. 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.

  The SBR that can be used in the present invention is obtained by copolymerizing styrene and butadiene. 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-polymerized styrene-butadiene copolymer rubber (hereinafter also referred to as E-SBR) can be produced by a conventional emulsion polymerization method that is publicly known or according to publicly known methods. For example, it can be obtained by emulsifying and dispersing a predetermined amount of styrene and butadiene monomer in the presence of an emulsifier, and emulsion polymerization with a radical polymerization initiator.

  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 anion polymerization in a solvent is used, and if desired, a polar compound Styrene and butadiene are polymerized in the presence of.

  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 in which a functional group is introduced into the SBR may be used as long as the effects of the present invention are not impaired. 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 of the polymer into which the functional group is introduced may be a polymerization terminal or a side chain of the polymer 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.

[Modified liquid diene rubber (B)]
The modified liquid diene rubber (B) used in the rubber composition of the present invention is a liquid polymer, and its melt viscosity measured at 38 ° C. is in the range of 0.1 to 10,000 Pa · s. A product obtained by adding a modifying compound to a modified liquid diene rubber (B ′). By including the modified liquid diene rubber (B) in the rubber composition of the present invention, a rubber composition exhibiting excellent processability and adhesiveness can be obtained.

  The unmodified liquid diene rubber (B ′) used as a raw material for the modified liquid diene rubber is preferably a polymer obtained by polymerizing the conjugated diene (b1) by the method described below. Examples of the conjugated diene (b1) include butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1, Examples include 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.

  The unmodified 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.

  The ratio of the aromatic vinyl compound (b2) unit to the total of units derived from the conjugated diene (b1) and the aromatic vinyl compound (b2) in the unmodified liquid diene rubber (B ′) is determined by processing the composition. From the viewpoints of properties, adhesiveness and the like, it is preferably 70% by mass or less, more preferably 60% by mass or less, and further preferably 50% by mass or less.

The unmodified liquid diene rubber (B ′) can be produced, for example, by an emulsion polymerization method or a solution polymerization method.
As the emulsion polymerization method, a known method or a method according to a known method can be applied. For example, a monomer containing a predetermined amount of conjugated diene is emulsified and dispersed in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator.

  Examples of the emulsifier include long chain fatty acid salts having 10 or more carbon atoms and rosinates. Examples of the long chain fatty acid salts include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid, and the like.

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 hindered.
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 resulting unmodified liquid diene rubber (B ′), a chain transfer agent may 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.

  The temperature of the emulsion polymerization can be appropriately set depending on the type of the radical polymerization initiator to be used, but is usually in the range of 0 to 100 ° C, preferably in the range of 0 to 60 ° C. 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 liquid diene rubber (B ′) is coagulated while adjusting the pH of the coagulation system to a predetermined value by adding an acid, and then the polymer (B) is recovered by separating the dispersion solvent. Next, after washing with water, dehydration, and drying, the liquid diene rubber (B ′) is obtained. In the course of coagulation, if necessary, latex and an extending oil previously made into an emulsified dispersion may be mixed and recovered as an oil-modified unmodified liquid diene rubber (B ′).

  As the solution polymerization method, a known method or a method according to a known method can be applied. For example, using a Ziegler catalyst, a metallocene catalyst, an anion-polymerizable active metal or an active metal compound in a solvent, a monomer containing a conjugated diene is polymerized in the presence of a polar compound as necessary. .

  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 are exemplified.

  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 methyl lithium, ethyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium, hexyl lithium, phenyl lithium and stilbene lithium; Polyfunctional organolithium compounds such as 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene and the like. Among these organic alkali metal compounds, organic lithium compounds are preferable, and organic monolithium compounds are more preferable.

  The amount of the organic alkali metal compound used can be appropriately set according to the melt viscosity, molecular weight, etc. of the unmodified liquid diene rubber (B ′) and the modified liquid diene rubber (B). It is usually used in an amount of 0.01 to 3 parts by mass with respect to 100 parts by mass of the body.

  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.

  Polar compounds are usually used in anionic polymerization to adjust the microstructure of the conjugated diene moiety 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 organic alkali metal compound.

  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 unmodified liquid diene rubber (B ′), or the polymerization reaction liquid is washed with water, separated, and dried to remove the above-mentioned unreacted liquid. The modified liquid diene rubber (B ′) can be isolated.

As a method for producing the unmodified liquid diene rubber (B ′), the solution polymerization method is preferable among the above methods.
The unmodified liquid diene rubber (B ′) thus obtained may be modified with the functional group described later as it is, but at least one of the unsaturated bonds contained in the liquid diene rubber. Modification may be carried out after hydrogenation of the part.

  The unmodified liquid diene rubber (B ′) is modified with various functional groups and used as a modified liquid diene rubber (B). 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.

  Examples of the method for producing the modified liquid diene rubber (B) include, for example, tin tetrachloride, dibutyltin chloride, tetrachlorosilane, dimethyldichlorosilane, and dimethyldiethoxy that can react with a polymerization active terminal before adding a polymerization terminator. Modified compounds that are coupling agents such as silane, tetramethoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylene diisocyanate, Polymerized terminal-modified compounds such as 4′-bis (diethylamino) benzophenone, N-vinylpyrrolidone, N-methylpyrrolidone, 4-dimethylaminobenzylideneaniline, dimethylimidazolidinone, or other compounds described in JP2011-132298A Add the modifying compound, Method for adding the modification of the liquid diene rubber (B ') can be mentioned.

  Further, from the viewpoint of economy and the like, a modification produced by a graft reaction in which an unsaturated carboxylic acid and / or an unsaturated carboxylic acid derivative is added as a modifying compound to an unmodified liquid diene rubber (B ′) after isolation. The liquid diene rubber (B) is preferably used in the present invention.

Examples of the unsaturated carboxylic acid include maleic acid, fumaric acid, itaconic acid, and (meth) acrylic acid.
Examples of the unsaturated carboxylic acid derivative include unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride, maleic acid esters, fumaric acid esters, itaconic acid esters, glycidyl (meth) acrylate, and hydroxyethyl (meth). Examples thereof include unsaturated carboxylic acid esters such as acrylate, unsaturated carboxylic acid amides such as maleic acid amide, fumaric acid amide, and itaconic acid amide, and unsaturated carboxylic acid imides such as maleic acid imide and itaconic acid imide.

  Among these, maleic anhydride was added to the unmodified liquid diene rubber (B ′) as a modifying compound from the viewpoints of economically and sufficiently exhibiting properties as a rubber composition and a crosslinked product of the present invention. Maleic anhydride-modified liquid diene rubber is preferable, maleic anhydride-modified liquid polybutadiene and maleic anhydride-modified liquid polyisoprene are more preferable, and maleic anhydride-modified liquid polyisoprene is still more preferable.

  The method for adding the modifying compound to the unmodified liquid diene rubber (B ′) is not particularly limited. For example, an unsaturated carboxylic acid or a derivative thereof is added to the liquid diene rubber, and a radical catalyst is added if necessary. Thus, a method of heating in the presence or absence of an organic solvent can be employed.

  Examples of the organic solvent used in the above method generally include hydrocarbon solvents and halogenated hydrocarbon solvents. Among these organic solvents, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene and xylene are preferable.

  Examples of the radical catalyst used in the above method include di-s-butylperoxydicarbonate, t-amylperoxypivalate, t-amylperoxy-2-ethylhexanoate, and azobisisobutyronitrile. It is done. Among these radical catalysts, azoisobutyronitrile is preferable.

  Further, as described above, after adding an unsaturated carboxylic anhydride to an unmodified liquid diene rubber (B ′) to obtain an anhydrous unsaturated carboxylic acid modified liquid diene rubber, the unsaturated carboxylic acid anhydride is further added. Reaction of the modified liquid diene rubber with alcohol, ammonia, amine or the like to produce an unsaturated carboxylic acid ester-modified liquid diene rubber, an unsaturated carboxylic acid amide-modified liquid diene rubber, or an unsaturated carboxylic imide-modified liquid diene A rubber may be produced and used as the modified liquid diene rubber (B).

  The addition reaction rate of the modifying compound of the modified liquid diene rubber (B) is 40 to 100 mol%, preferably 60 to 100 mol%, more preferably 80 to 100 mol%, and 90 to 100 mol%. More preferably. If the addition reaction rate is within the above range, the resulting modified liquid diene rubber (B) is less likely to have a modified compound or a low-molecular compound derived from the modified compound. It is possible to further suppress adverse effects such as metal corrosion that may be derived from acidic components such as maleic anhydride. For example, when an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative is used as the modifying compound, the unreacted modification rate is obtained by comparing the acid value before and after washing in the sample after the modification reaction. The amount of the compound can be calculated and determined.

  As a method for producing the modified liquid diene rubber (C) having a specific addition reaction rate, it is effective to react the reaction for adding the modifying compound at an appropriate reaction temperature for a sufficient reaction time. For example, the temperature in the reaction for adding maleic anhydride to the unmodified liquid diene rubber (C ′) is preferably 100 to 200 ° C., more preferably 120 to 180 ° C. The reaction time is preferably 3 to 200 hours, more preferably 4 to 100 hours, and further preferably 5 to 50 hours.

  The amount of the modified compound added to the modified liquid diene rubber (B) is not strictly limited, but from the viewpoint of sufficiently exhibiting the characteristics of the resulting rubber composition and crosslinked product, an unmodified polymer. The range of 0.05-40 mass parts is preferable with respect to 100 mass parts, the range of 0.1-30 mass parts is more preferable, and the range of 0.1-20 mass parts is still more preferable. When the amount of the modified compound added is more than 40 parts by mass, the flexibility and strength of the resulting crosslinked product tend to decrease, and when it is less than 0.05 parts by mass, the adhesion of the resulting crosslinked product decreases. Tend to.

  The amount of the modified compound added to the modified liquid diene rubber (B) can be calculated based on the addition reaction rate of the modified compound, or various analyzes such as infrared spectroscopy and nuclear magnetic resonance spectroscopy. It can also be determined using equipment.

  In this modified liquid diene rubber (B), the position at which the functional group is introduced may be a polymerization terminal or a side chain of a polymer chain. Moreover, the said functional group may be contained individually by 1 type, and may be contained 2 or more types. Therefore, the modified liquid diene rubber (B) may be modified with one modified compound, or may be modified with two or more modified compounds.

  The melt viscosity of the modified 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. Is in the range of 0.5 to 5,000 Pa · s, more preferably in the range of 1 to 3,000 Pa · s. When the melt viscosity of the modified liquid diene rubber (B) is within the above range, kneading of the resulting rubber composition is facilitated and processability is improved. Furthermore, the adhesiveness of the crosslinked product obtained from the rubber composition is also improved. In the present invention, the melt viscosity of the modified liquid diene rubber (B) is a value determined by the method described in Examples described later.

  The maximum peak molecular weight (Mt) of the modified liquid diene rubber (B) is 3,000 to 120,000, preferably 4,000 to 110,000, more preferably 5,000 to 100,000, and 6,000. -90,000 is still more preferable, and 7,000-70,000 is still more preferable. When the Mt of the modified liquid diene rubber (B) is within the above range, the viscosity becomes low, kneading of the rubber composition is facilitated, processability is improved, and adhesion is further improved. In the present invention, Mt of the modified liquid diene rubber (B) is the maximum peak molecular weight in terms of polystyrene determined from measurement by gel permeation chromatography (GPC).

  In the modified liquid diene rubber (B), the total area derived from the polymer in the GPC chromatogram obtained by the GPC measurement is 100%, and the ratio of the polymer in the region where the molecular weight is Mt × 1.45 or more is 0. It is characterized by being in the range of ˜20%. By blending such a modified liquid diene rubber (B) into the rubber composition, not only is the workability when using the composition excellent, but also a crosslinked product excellent in adhesion and metal corrosion resistance is obtained. Can be made. Although the details of the reason are not clear, a polymer having a molecular weight in the region of Mt × 1.45 or more, typically a coupling, produced when the unmodified liquid diene rubber (B ′) is modified. When the content of the high molecular weight substance derived from a by-product such as a body is in the above range, a rubber composition having excellent workability can be produced, and the diene rubber can be efficiently modified. Therefore, it is presumed that the remaining amount of the substance derived from the modifying compound that was not used for modifying the liquid diene rubber is small, so that adverse effects such as metal corrosion and adhesive deterioration are suppressed.

  From the viewpoint of processability and adhesiveness, the proportion of the polymer having a molecular weight in the region of Mt × 1.45 or more is preferably in the range of 0 to 15%, and in the range of 0 to 10%. More preferred. In the present invention, the ratio of the polymer having a molecular weight in the region of Mt × 1.45 or higher is determined by GPC chromatography obtained when gel permeation chromatography (GPC) measurement is performed under the conditions described in the examples described later. It is a value obtained from the area ratio of the polymer in the region when the total area derived from the polymer in grams (area surrounded by the GPC chromatogram and the baseline) is 100%.

As a technique for producing such a modified liquid diene rubber (B) having a specific molecular weight distribution, for example, an unmodified liquid diene is added while an anti-aging agent is added during the reaction of adding a modifying compound described later. Examples thereof include purifying the system rubber (B ′) and sufficiently removing components that inhibit the reaction of adding the modifying compound. 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.

Further, as a method for synthesizing the modified liquid diene rubber (B) having a specific molecular weight distribution, for example, it is effective to add an anti-aging agent during the reaction of adding the modified compound after the purification . Preferred anti-aging agents used at this time include 2,6-di-t-butyl-4-methylphenol (BHT), 2,2′-methylenebis (4-methyl-6-t-butylphenol), 4,4′-. Thiobis (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol) (AO-40), 3,9-bis [1,1-dimethyl-2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane (AO-80), 2, 4-bis [(octylthio) methyl] -6-methylphenol (Irganox 1520L), 2,4-bis [(dodecylthio) methyl] -6-methylphenol (Irganox 1726), 2- [1- ( 2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate (Sumilizer GS), 2-t-butyl-6- (3-t-butyl-2-hydroxy -5-methylbenzyl) -4-methylphenyl acrylate (Sumilizer GM), 6-t-butyl-4- [3- (2,4,8,10-tetra-t-butyldibenzo [d, f] [1 , 3,2] dioxaphosphepin-6-yloxy) propyl] -2-methylphenol (Sumilizer GP), tris (2,4-di-t-butylphenyl) phosphite (Irgafos 168), dioctadecyl 3 , 3′-dithiobispropionate, hydroquinone, p-methoxyphenol, N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine (NOCRACK 6) C), bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (LA-77Y), N, N-dioctadecylhydroxylamine (Irgastab FS 042), bis (4-t-octylphenyl) An amine (Irganox 5057) etc. are mentioned. Moreover, the said anti-aging agent may be used individually by 1 type, and may use 2 or more types together.

  The addition amount of the anti-aging agent is preferably 0.01 to 10 parts by mass, and 0.1 to 3 parts by mass with respect to 100 parts by mass of the unmodified liquid diene rubber (B ′) or the modified liquid diene rubber (B). Part is more preferred.

  Furthermore, as a method for synthesizing the modified liquid diene rubber (B) having a specific molecular weight distribution, appropriate temperature control during the reaction of adding the modifying compound is also effective. For example, the temperature in the reaction of adding maleic anhydride to the unmodified liquid diene rubber (B ′) is preferably from 100 to 200 ° C., more preferably from 120 to 180 ° C.

The method for producing the modified liquid diene rubber (B) having these specific molecular weight distributions may be performed in combination of two or more, or all three.
The weight average molecular weight (Mw) of the modified liquid diene rubber (B) is preferably 3,000 to 500,000, more preferably 4,000 to 400,000, more preferably 5,000 to 300,000, 000 to 300,000 is even more preferable. When the Mw of the modified liquid diene rubber (B) is within the above range, the processability of the rubber composition of the present invention is good, and the adhesiveness of the crosslinked product is good. In the present invention, two or more kinds of modified liquid diene rubbers (B) having different Mw may be used in combination.

  The molecular weight distribution (Mw / Mn) of the modified 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 in the above-mentioned range because the variation of the viscosity of the resulting modified liquid diene rubber (B) is small.

  The glass transition temperature (Tg) of the modified liquid diene rubber (B) is the vinyl content of units derived from the conjugated diene (b1), the type of conjugated diene (b1), and the units derived from monomers other than the conjugated diene. Although it may vary depending on the content and the like, -100 to 30 ° C is preferable, -100 to 20 ° C is more preferable, and -100 to 10 ° C is more preferable. When the Tg is in the above range, for example, the processability and adhesiveness of the rubber composition are good. Moreover, it can suppress that a viscosity becomes high and can handle it easily. The vinyl content of the modified liquid diene rubber (B) is preferably 99% by mass or less, and more preferably 90% by mass or less. The modified liquid diene rubber (B) may be used alone or in combination of two or more.

In the rubber composition of the present invention, the rubber component is composed of the solid rubber (A) and the liquid diene rubber (B).
This 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 diene system. Rubber (B) 95 to 1% by mass, more preferably 10 to 90% by mass of solid rubber (A) and 90 to 10% by mass of liquid diene rubber (B), more preferably 20 to 80% by mass of solid rubber (A) And 80 to 20% 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 and adhesiveness 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 (C) is a particulate form, the shape of the particle | grain can take various shapes, such as a spherical shape, according to a desired physical property. In addition, when the filler (C) is in the form of particles, it may be either solid particles or hollow particles depending on the desired physical properties, etc., or a core-shell type formed of a plurality of materials. It may be a particle. Further, these fillers (C) 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, and calcium carbonate and carbon black are more preferable from the viewpoint of the reinforcing property, cost, ease of handling, and the like of the obtained rubber composition and its crosslinked product. . 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 content of the filler (C) with respect to 100 parts by mass of the rubber component comprising the solid rubber (A) and the liquid diene rubber (B) is 0.1 to 1500 parts by mass. -1300 mass parts is preferable, 5-1000 mass parts is more preferable, and 10-800 mass parts is still more preferable. 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 individually by 1 type, and may use 2 or more types together.

  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 composed of the solid rubber (A) and the liquid diene rubber (B) is 0.1 to 500 parts by mass, 450 mass parts is preferable, 5-400 mass parts is more preferable, 8-350 mass parts is still more preferable. 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 in order to crosslink the rubber. 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 0.1 to 10 parts by mass, preferably 0 to 100 parts by mass of the rubber component composed of the solid rubber (A) and the liquid diene rubber (B). 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 included as a crosslinking agent for crosslinking (vulcanizing) the rubber. 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. Compounds, xanthate compounds, and the like. These vulcanization accelerators may be used alone or in combination of two or more. The vulcanization accelerator is usually contained in an amount of 0.1 to 15 parts by mass, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component comprising the solid rubber (A) and the liquid diene rubber (B). Is done.

  The rubber composition of the present invention may further contain a vulcanization aid when sulfur, a sulfur compound, or the like is contained as a crosslinking agent for crosslinking (vulcanizing) the rubber, for example. 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 said vulcanization | cure adjuvant is 0.1-15 mass parts normally with respect to the rubber component which consists of solid rubber (A) and liquid diene type rubber (B), Preferably it contains 0.5-10 mass parts.

  The rubber composition of the present invention is intended to improve processability, fluidity, etc. within a range that does not impair the effects of the invention, and if necessary, an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin, a C9 resin, It may contain tackifying resins such as rosin resins, coumarone / indene resins and phenol resins.

  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 , May contain additives such as mold release agents, foaming agents, antibacterial agents, antifungal agents, perfumes, dispersants, solvents and the like.

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 above mixing can be carried out under normal pressure and in an air atmosphere, but it is preferable to carry out 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.

[Crosslinked product]
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. The crosslinking conditions of the rubber composition can be appropriately set according to the use and the like. For example, a crosslinked product can be produced by performing a crosslinking reaction at a temperature range of 130 ° C. to 250 ° C. for 10 minutes to 60 minutes. . For example, when the rubber composition of the present invention is used in an automobile production line, the rubber composition of the present invention is applied to desired parts of various members (for example, gaps between flanges of a plurality of frame members) When baking and drying is performed in the electrodeposition coating process, 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.)
<Modified liquid diene rubber (B)>
Modified liquid polyisoprene obtained in Production Examples 1 to 5 described later <Filler (C)>
Calcium carbonate Shiraka Hana CCR
<Oil (D)>
Naphthenic oil SUNTHENE 250 (manufactured by Nippon Sun Oil Co., Ltd.)
<Crosslinking agent>
Sulfur (fine sulfur 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.)
<Vulcanization accelerator>
Vulcanization accelerator (1): Noxeller DM (made by 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.)
<Optional component>
NOCRACK NS-6 (Ouchi Shinsei Chemical Co., Ltd.)

Production Example 1: Production of Modified 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 placed in this pressure vessel. After charging and heating 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. Thereafter, methanol was added to stop the polymerization reaction, and a polymerization solution (2695 g) was obtained. Water was added to the obtained polymerization reaction liquid and stirred, and the polymerization reaction liquid was washed with water. Stirring was terminated, and after confirming that the polymerization solution phase and the aqueous phase were separated, water was separated. The polymerization reaction liquid after completion of washing was dried at 70 ° C. for 12 hours to obtain unmodified liquid polyisoprene (B′-1).

  Subsequently, 300 g of the obtained unmodified liquid polyisoprene (B′-1) was charged into a 1-liter autoclave subjected to nitrogen substitution, and 4.5 g of maleic anhydride and 2,6-di-t-butyl- 4-methylphenol (BHT) 3.0g was added and it was made to react at 160 degreeC for 20 hours, and the maleic anhydride modified liquid polyisoprene (B-1) was obtained.

  The addition reaction rate of the modified compound is 99 mol%, and the amount of the modified compound added to the modified liquid polyisoprene (B-1) is 1.5 mass with respect to 100 parts by mass of the unmodified liquid polyisoprene (B′-1). Was part. Table 1 shows the physical properties of the resulting modified liquid polyisoprene (B-1).

Production Example 2: Production of modified liquid polyisoprene (B-2) Unmodified liquid polyisoprene (B'-1) obtained by the same procedure as in Production Example 1 in a 1 liter autoclave subjected to nitrogen substitution 300 g was charged, 4.5 g of maleic anhydride and 1.0 g of BHT were added and reacted at 160 ° C. for 20 hours to obtain maleic anhydride-modified liquid polyisoprene (B-2).

  The addition reaction rate of the modified compound is 99 mol%, and the amount of the modified compound added to the modified liquid polyisoprene (B-2) is 1.5 mass with respect to 100 parts by mass of the unmodified liquid polyisoprene (B′-1). Was part. Table 1 shows the physical properties of the resulting modified liquid polyisoprene (B-2).

Production Example 3: Production of modified liquid polyisoprene (B-3) Unmodified liquid polyisoprene (B'-1) obtained by the same procedure as in Production Example 1 in a 1 liter autoclave subjected to nitrogen substitution 300 g was charged, 4.5 g of maleic anhydride was added, and the mixture was reacted at 160 ° C. for 20 hours to obtain maleic anhydride-modified liquid polyisoprene (B-3).

  The addition reaction rate of the modified compound is 99 mol%, and the amount of the modified compound added to the modified liquid polyisoprene (B-3) is 1.5 mass with respect to 100 parts by mass of the unmodified liquid polyisoprene (B′-1). Was part. Table 1 shows the physical properties of the resulting modified liquid polyisoprene (B-3).

Production Example 4: Production of modified liquid polyisoprene (B-4) Unmodified liquid polyisoprene (B'-1) obtained by the same procedure as in Production Example 1 in a 1 liter autoclave subjected to nitrogen substitution 300 g was charged, 4.5 g of maleic anhydride and 1.0 g of BHT were added, and reacted at 160 ° C. for 150 minutes to obtain maleic anhydride-modified liquid polyisoprene (B-4).

  The addition reaction rate of the modifying compound was 35 mol%, and the amount of the modifying compound added to the modified liquid polyisoprene (B-4) was 0.53 mass relative to 100 parts by mass of the unmodified liquid polyisoprene (B′-1). Was part. Table 1 shows the physical properties of the resulting modified liquid polyisoprene (B-4).

Production Example 5: Production of modified liquid polyisoprene (B-5) Unmodified liquid polyisoprene (B'-1) obtained in the same procedure as in Production Example 1 in a 1-liter autoclave subjected to nitrogen substitution 300 g was charged, 4.5 g of maleic anhydride and 1.0 g of BHT were added, and reacted at 160 ° C. for 30 minutes to obtain maleic anhydride-modified liquid polyisoprene (B-5).

The addition reaction rate of the modifying compound was 10 mol%, and the amount of the modifying compound added to the modified liquid polyisoprene (B-5) was 0.15 mass relative to 100 parts by mass of the unmodified liquid polyisoprene (B′-1). Was part. Table 1 shows the physical properties of the resulting modified liquid polyisoprene (B-5).
In addition, the measuring method and calculation method of each physical property value of the modified liquid diene rubber (B) are as follows.

(Measurement method of weight average molecular weight, maximum peak molecular weight and molecular weight distribution)
Mw, Mt, and Mw / Mn of the modified liquid diene rubber (B) were determined by GPC (gel permeation chromatography) in terms of 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

  In addition, the ratio of the polymer in the region where the molecular weight is Mt × 1.45 or more is obtained from the GPC chromatogram obtained by the GPC measurement under the above conditions to determine the area of the polymer in the region of Mt × 1.45 or more. Then, the total area derived from the polymer (area surrounded by the GPC chromatogram and the baseline) was determined as an area ratio when 100%.

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

(Measurement method of glass transition temperature)
Ten milligrams of the modified liquid diene rubber (B) is collected in an aluminum pan, and a thermogram is measured by differential scanning calorimetry (DSC) at a heating rate of 10 ° C./min. It was.

(Addition reaction rate)
To 3 g of the sample after the denaturation reaction, 180 mL of toluene and 20 mL of ethanol were added and dissolved, and then neutralization titration with an ethanol solution of 0.1 N potassium hydroxide was performed to determine the acid value.
Acid value (mgKOH / g) = (A−B) × F × 5.661 / S
A: A drop amount of ethanol solution of 0.1N potassium hydroxide required for neutralization (mL)
B: 0.1N potassium hydroxide ethanol solution drop volume in a blank containing no sample (mL)
F: Potency of ethanol solution of 0.1N potassium hydroxide S: Weight of sample weighed (g)

The sample after the denaturation reaction was washed 4 times with methanol (5 mL relative to 1 g of the sample) to remove unreacted maleic anhydride, and then the sample was dried under reduced pressure at 80 ° C. for 12 hours. The acid value was determined by the method. The addition reaction rate of the modifying compound was calculated based on the following formula.
[Addition reaction rate of modifying compound] = [Acid value after washing] / [Acid value before washing] × 100

(Amount of modified compound added)
From the addition reaction rate determined above, the amount of functional groups added to the unreacted liquid diene rubber was calculated according to the following formula.
[Amount of modified compound added to 100 parts by mass of unmodified liquid diene rubber (B ′)] = [Mass of added maleic anhydride (g)] × [Addition reaction rate of modified compound (mol%)] / [Mass (g) of unmodified liquid diene rubber (B ′)]

(Examples 1-2 and Comparative Examples 1-4)
According to the blending ratio (parts by mass) listed in Table 2, polybutadiene rubber, modified liquid diene rubbers (B-1) to (B-5), calcium carbonate, naphthenic oil, stearic acid, zinc white, anti-aging agent And kneaded at 50 ° C. using a Brabender. Next, sulfur and a vulcanization accelerator were added in the proportions shown in Table 2, and kneaded at 50 ° C. to obtain a rubber composition. Each evaluation was performed based on the following method about the obtained rubber composition. The results are shown in Table 2.

(1) Workability The workability when the obtained rubber composition was filled in a cartridge gun and applied on a steel plate was evaluated. The ones that were easy to apply and had no stringing were marked with ◯, the ones with high viscosity that were difficult to apply, and the ones that were stringed were marked with ×.

(2) Shear adhesive strength Shear adhesive strength 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 the steel sheet so as to have a thickness of 1 mm, and then cross-linked at 150 ° C. for 30 minutes to prepare a sample, and the shear adhesive force was measured. The tensile speed when measuring the shear adhesive force was 50 mm / min.
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 larger the numerical value, the better the shear adhesive strength of the rubber composition.

(3) Metal corrosiveness After apply | coating the rubber composition to a SPCC-SD steel plate so that it might become thickness 1mm, it bridge | crosslinked on 150 degreeC and the conditions for 30 minutes, and produced the sample. The obtained sample was allowed to stand for 4 weeks under conditions of 23 ° C. and 50% RH, and then the crosslinked product of the rubber composition was peeled off from the steel plate, and the state of rust generation on the steel plate surface was evaluated. The thing which does not generate | occur | produce rust at all is set as (circle), and the thing which has generated rust is set as *.

  Comparing Example 1 or 2 with Comparative Example 1 or 2, a rubber composition using a modified liquid isoprene rubber in which the ratio of the polymer having a molecular weight in the region of Mt × 1.45 or more is within the scope of the present invention. The viscosity is higher than that of the rubber composition of Comparative Example 1 using the modified liquid isoprene rubber (B-3) in which the proportion of the polymer having a molecular weight in the region of Mt × 1.45 or more is outside the scope of the present invention. It can be seen that it is low and excellent in workability. It can be seen that Comparative Example 2 in which the amount of oil added was increased in order to improve workability, but the workability was improved, but the shear adhesive strength was reduced.

  Moreover, when Example 1 or 2 is compared with Comparative Example 3 or 4, it can be seen that when a modified liquid isoprene rubber having a low addition reaction rate is used, the shear adhesive force is low and the metal corrosivity is adversely affected.

  The rubber composition obtained in the present invention is excellent in workability, and the cross-linked product obtained from this rubber composition is also excellent in adhesion and metal corrosion resistance. Therefore, it 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 (2)

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 rubber component consisting of 1 to 99% by mass of seed solid rubber (A) and 99 to 1% by mass of modified liquid diene rubber (B) And a rubber composition containing 0.1 to 500 parts by mass of oil (D), wherein the modified liquid diene rubber (B) satisfies the following requirements (I) to (III).
(I) The melt viscosity of the modified liquid diene rubber (B) measured at 38 ° C. is in the range of 0.1 to 10,000 Pa · s.
(II) When measured by gel permeation chromatography (GPC), the maximum peak molecular weight (Mt) is in the range of 3,000 to 120,000, and the total area derived from the polymer in the resulting GPC chromatogram is 100%. As a result, the proportion of the polymer having a molecular weight in the region of Mt × 1.45 or more is 0 to 20%.
(III) The modified liquid diene rubber (B) is obtained by adding a modified compound to the liquid diene rubber (B ′), and the addition reaction rate of the modified compound is 40 to 100 mol%.   The rubber composition according to claim 1, wherein the modifying compound added to the liquid diene rubber (B ') is maleic anhydride.