WO2003064516A1

WO2003064516A1 - Rubber composition and process for producing the same

Info

Publication number: WO2003064516A1
Application number: PCT/JP2003/001003
Authority: WO
Inventors: Takeshi Karato; Yoshihiro Chino
Original assignee: Zeon Corporation
Priority date: 2002-01-31
Filing date: 2003-01-31
Publication date: 2003-08-07
Also published as: JP2003221471A

Abstract

A rubber composition which comprises: 20 to 80 parts by weight of a conjugated diene rubber (A) comprising 40 to 100 wt.% conjugated diene units and 0 to 60 wt.% aromatic vinyl monomer units and having a Mooney viscosity of 70 to 200; and 80 to 20 parts by weight of a conjugated diene rubber (B) comprising 40 to 99.8 wt.% conjugated diene units, 0 to 59.8 wt.% aromatic vinyl monomer units, and 0.2 to 20 wt.% aminated monomer units and having a Mooney viscosity which is 20 to 150 and is lower by at least 10 than that of the conjugated diene rubber (A) (the sum of the conjugated diene rubber (A) and the conjugated diene rubber (B) is 100 parts by weight). A compound obtained by compounding this rubber composition with a silica reinforcement gives, through molding with rolls, a sheet excellent in surface shape and tensile properties and reduced in heat build-up.

Description

TECHNICAL FIELD Rubber composition and method for producing the same

The present invention relates to a rubber composition and a method for producing the same, and more particularly, to a sheet obtained by molding a composition containing silica as a reinforcing agent into a sheet with a roll, and having excellent tensile properties and low tensile strength. The present invention relates to a rubber composition having excellent heat build-up and a method for producing the same. Background art

In recent years, resource conservation and environmental measures have been emphasized, and the demand for low fuel consumption of automobiles is becoming increasingly severe.Car tires are required to contribute to low fuel consumption by reducing rolling resistance. Have been.

In order to reduce the rolling resistance of a tire, it is known to use a rubber composition in which silica is compounded as a reinforcing agent in a conjugated gen-based rubber instead of rubber black. Such a rubber composition containing silica is excellent in low heat build-up as compared with a rubber composition containing carbon black, so that the rolling resistance of the tire can be reduced, but the abrasion resistance and tensile properties are poor. In order to solve this problem, it has been proposed to use a gen-based rubber obtained by copolymerizing a monomer having an amino group.

For example, JP-A-64-22940 discloses a conjugated gen-based rubber obtained by copolymerizing a conjugated gen and an amino group-containing monomer by a solution polymerization method using an organic alkali metal or the like as a polymerization catalyst. Disclosed is a silicide compounded rubber composition having improved breaking strength and abrasion resistance. Furthermore, this publication also discloses a specific compounding example in which a styrene-butadiene copolymer rubber having a natural rubber gum viscosity of about 50 is blended with the conjugated gen-based rubber. Such conjugated rubbers generally have a narrow molecular weight distribution and thus are inferior in processability, and the conjugated rubber blends described above have slightly improved processability. However, the balance between low heat build-up and tensile properties is poor. The rubber composition with poor processability is formed into a sheet by a roll. The resulting rubber composition is inferior in surface shape, making it difficult to form a green tire in the tire manufacturing process.

Japanese Patent Application Laid-Open (JP-A) No. 11-344 discloses that a tertiary amino group-containing monomer containing 1 to 20% by weight of an emulsion-copolymerized conjugated gen-based rubber has excellent tensile properties and low heat build-up. An excellent silica-containing rubber composition is disclosed. This publication also discloses a specific compounding example in which a styrene-butadiene copolymer rubber having a natural rubber gum viscosity of about 50 is blended with the conjugated gen-based rubber. In addition, the rubber composition containing such a conjugated diene rubber is inferior in processability, and the above rubber blend has insufficient heat resistance and low heat generation. Poor balance between properties and tensile properties.

Further, Japanese Patent Laid-Open No. 8- 1 thirty-four thousand two hundred seventy-two, and a 1 weight ^_0/0 less than tertiary amino group-containing Yutan weight conjugated diene-based and the body copolymerized rubber and silane coupling agent, the particular condition Discloses a silica compounded rubber composition kneaded in the above. Such a rubber composition is excellent in extrusion processability, and excellent in tensile properties, low heat generation, etc., but the surface shape of the rubber composition when formed into a sheet by rolls is not satisfactory. Did not. Disclosure of the invention

In view of the above-mentioned circumstances, an object of the present invention is to improve the surface shape of a sheet when a composition containing silica as a reinforcing agent is formed into a sheet by a roll, and to obtain tensile properties and low heat generation. An object of the present invention is to provide a rubber composition excellent in water resistance and a method for producing the same.

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and have a conjugated diene rubber having a relatively high viscosity with no amino group and a Mooney viscosity having a lower Mooney viscosity than that having an amino group. It has been found that a blend with a conjugated rubber is compounded with silica and gives a rubber composition which is excellent in the surface shape of a sheet when formed into a sheet by a roll, and which is excellent in tensile properties and low heat generation properties. Based on this finding, the present invention has been completed.

According to the present invention, 40 to 100% by weight of a conjugated diene unit, 0 to 60% by weight of an aromatic vinyl monomer unit and 0 to 20% of other copolymerizable monomer units according to the present invention. 20 to 80 parts by weight of a conjugated gen-based rubber (A) having a viscosity in the range of 70 to 200, and 40 to 99.8% by weight of a conjugated diene unit, and an aromatic vinyl monomer And 5 to 20% by weight of a monomer unit, 0.2 to 20% by weight of an amino group-containing monomer unit, and 0 to 20% by weight of another copolymerizable monomer unit. One viscosity is in the range of 20 to 150, and the conjugated rubber (A) contains 80 to 20 parts by weight of a conjugated rubber (B) having a Muney viscosity which is 10 or more lower than the mu viscosity of the conjugated rubber (A). (The total amount of the conjugated rubber (A) and the conjugated rubber (B) is 100 parts by weight.) A rubber composition is provided.

Further, according to the present invention, it is possible to mix the latex or solution of the conjugated rubber (A) with the latex or solution of the co-used rubber (B), and then separate the dispersion medium from the mixed solution. The present invention provides a method for producing the rubber composition containing a conjugated diene rubber (A) and a conjugated diene rubber (B). BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The rubber composition of the present invention contains 40 to 100% by weight of a conjugated gen unit and 0 to 60% by weight of an aromatic vinyl monomer unit, and has a viscosity of 70 to 200. 20 to 80 parts by weight of a diene rubber (A), 40 to 99.8% by weight of a conjugated diene unit, 0 to 59.8% by weight of an aromatic vinyl monomer unit, and 0.2 to 2% of an amino group-containing monomer unit It comprises 20 weight ^0, the range of beam one knee viscosity from 20 to 150, the conjugated diene-based rubber having a low厶one knee viscosity 10 more than arm one knee viscosity of the conjugated diene rubber (a) (B) 80 ~ 20 parts by weight (the total amount of the conjugated rubber (A) and the conjugated rubber (B) is 100 parts by weight;).

The conjugated diene rubber (A) has a conjugated diene unit of 40 to 100% by weight, preferably 50 to 90% by weight, more preferably 55 to 80% by weight, and an aromatic vinyl monomer unit 0 to 60% by weight, preferably Contains 10 to 50% by weight ⁰ / o, more preferably 20 to 45% by weight, and has a Mooney viscosity (ML _{l + 4} , 100) of 70 to 200, preferably 90 to 160, more preferably 100 It is in the range of ~ 150.

If the conjugated diene unit amount in the conjugated diene rubber (A) is small, low heat build-up is inferior. Both When the amount of the aromatic vinyl monomer unit in the role-based rubber (A) is large, low heat build-up is inferior. The conjugated rubber (A) preferably contains an aromatic vinyl monomer unit from the viewpoint of more excellent tensile properties.

The conjugated gen-based rubber (A) contains other copolymerizable monomer units other than the conjugated gen unit and the aromatic vinyl monomer unit as long as the effects of the present invention are not essentially impaired. Is also good. The amount of the copolymerizable monomer is usually 20% by weight or less, more preferably 10% by weight 0/0 or less in all monomer units. If this amount is too large, the physical property balance of the crosslinked rubber tends to deteriorate.

Preferably, the conjugated rubber (A) does not contain an amino group-containing monomer unit. However, it may contain amino group-containing monomer units in a range that does not substantially impair the effects of the present invention, usually less than 0.2% by weight, particularly less than 0.1% by weight. If this amount is too large, the viscosity of the composition becomes too high, making it difficult to apply, or the surface shape of the sheet becomes poor.

If the conjugated diene rubber (A) has a low viscosity, low heat build-up and abrasion resistance are inferior. Conversely, if it is high, the surface shape of the sheet deteriorates and the viscosity of the compound becomes too high. It becomes difficult to add.

The conjugated diene rubber (B) has a conjugated diene unit content of 40 to 99.8% by weight, preferably 50 to 89.% by weight, more preferably 55 to 79.6% by weight, and an aromatic vinyl monomer unit 0- 59.8 weight ⁰ / o, preferably 1 0 to 49. off weight ⁰ / o, more preferably from 20 to 44.6 by weight%, and an amino group-containing monomer units 0.2 to 20 wt%, preferably Contains 0.3 to 10% by weight, more preferably 0.4 to 5% by weight.

When the amount of conjugated gen units in the conjugated gen-based rubber (B) is small, low heat buildup is inferior. When the amount of the aromatic vinyl monomer unit of the synergistic gen-based rubber (B) is large, low heat build-up is inferior. It is preferable that the synergistic gen-based rubber (B) contains an aromatic vinyl monomer unit from the viewpoint of more excellent tensile properties.

If the amount of the amino group-containing monomer unit in the conjugated diene-based rubber (B) is small, low heat build-up and abrasion resistance are inferior. Conversely, if it is large, the surface shape of the sheet becomes poor.

The conjugated gen-based rubber (B) is a component other than a conjugated gen unit, an aromatic vinyl monomer unit and an amino group-containing monomer unit as long as the effect of the present invention is not substantially impaired. May contain other copolymerizable monomer units. The amount of this copolymerizable monomer unit is usually at most 20% by weight, especially at most 10% by weight. If the amount is too large, the physical property balance of the crosslinked rubber tends to deteriorate.

The conjugated rubber (B) has a viscosity at ML ( ₊₄ , 100 ° C.) of 20-150, preferably 40-"! 30, more preferably 50-100. The viscosity is lower than the viscosity of the conjugated rubber (A) by 10 or more, preferably 20 or more, more preferably 25 or more.

If the conjugated diene rubber (B) has low viscosity, low heat build-up and abrasion resistance are inferior. Conversely, if it is high, the surface shape of the sheet deteriorates and the compound viscosity becomes too high. It becomes difficult to add. If the difference between the viscosity of the conjugated rubber (B) and the viscosity of the conjugated rubber (A) is too small, the surface shape of the sheet may deteriorate or the viscosity of the compound may be reduced. It becomes too high and difficult to process.

The ratio of the conjugated rubber (A) to the conjugated rubber (B) is 20 to 80 parts by weight, preferably 30 to 7 parts by weight, based on a total of 100 parts by weight of both. It is 5 parts by weight, more preferably 40 to 70 parts by weight. If the amount of the conjugated diene rubber (A) is small, the surface shape of the sheet is deteriorated, or the viscosity of the compound is too high, making it difficult to apply. Conversely, if the amount is large, the tensile properties and low heat build-up are poor.

Examples of the conjugated gen include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, and the like. Is mentioned. Among these, 1,3-butadiene is preferred. These can be used alone or in combination of two or more.

As the aromatic vinyl monomer, an aromatic vinyl compound having no amino group is used. For example, styrene, a-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropyl Examples include styrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene, and monofluorostyrene. Of these, styrene is preferred. These can be used alone or in combination of two or more.

Amino group-containing monomers are selected from primary, secondary and tertiary amino groups in one molecule. Preferred are polymerizable monomers having at least one amino group, particularly those having a tertiary amino group.

Examples of the primary amino group-containing monomer include acrylamide, methacrylamide, p-aminostyrene, aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, aminobutyl (meth) acrylate And the like.

Examples of the secondary amino group-containing monomer include anilinostyrenes disclosed in JP-A-61-130355; N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methylolacrylamide N- (4-anilinophenyl) methacrylamide; N-monosubstituted (meth) acrylamides;

Examples of the tertiary amino group-containing monomer include N, N-disubstituted aminoalkyl (meth) acrylate, N, N-disubstituted aminoalkyl (meth) acrylamide, N, N-disubstituted aminoaromatic Examples thereof include a vinyl compound and a polymerizable monomer having a pyridyl group.

Examples of N, N-disubstituted aminoalkyl (meth) acrylate include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate. ) Acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate ) Acrylate, N-methyl-1-N-ethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dibutyla Minopropyl (meth) acrylate, N, N-dibutylaminobutyl (meth) acrylate, N, N-dihexyl Aminoethyl (meth) Akurireto, N, N-di-O-lipped Le aminoethyl (meth) Akurireto the like. Among these, N, N-dimethylaminoethyl (meth) acrylate, N, N-getylaminoethyl (meth) acrylate, and N, N-dipropylaminoethyl (meth) acrylate are preferred.

Examples of N, N-disubstituted aminoalkyl (meth) acrylamide include N, N-dimethylaminomethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl ( (Meth) acrylamide, N, N-dimethylaminobutyl (meth) acrylamide, N, N-getylaminoethyl (meth) acrylamide, N, N- Getylaminopropyl (meth) acrylamide, N, N-getylaminobutyl (meth) acrylamide, N-methyl-1-N-ethylaminoethyl (meth) acrylamide, N, N-dipropylaminoethyl (meth) ) Acrylamide, N, N-dibutylaminoethyl (meth) acrylamide, N, N-dibutylaminopropyl (meth) acrylamide, N, N-dibutylaminobutyl (meth) acrylamide, N, N-dihexylamino Ethyl (meth) acrylamide, N, N-dihexylaminopropyl (meth) acrylamide, N, N-dioctylaminopropyl (meth) acrylamide and the like. Among these, N, N-dimethylaminopropyl (meth) acrylamide and N, N-getylaminopropyl (meth) acrylamide are preferred.

Examples of the N, N-disubstituted aminoalkyl aromatic vinyl compound include N, N-dimethylaminoethylstyrene, N, N-getylaminoethylstyrene, N, N-dipropylaminoethylstyrene, N, N —Dioctylaminoethylstyrene and the like.

Examples of the polymerizable monomer having a pyridyl group include 2-vinylpyridine, 4-vinylpyridine, 5-methyl-1-vinylpyridine, 5-ethyl-2-vinylpyridine, and the like. Of these, 2-vinylpyridine and 4-vinylpyridine are preferred.

These amino group-containing monomers can be used alone or in combination of two or more.

Other monomers other than the conjugated gen, the aromatic vinyl monomer and the amino group-containing monomer may be copolymerizable with the conjugated gen, the aromatic vinyl monomer and the amino group-containing monomer. Specific examples thereof include, but are not limited to, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethyl (meth) acrylate. Ethylenically unsaturated carboxylic acid ester monomers such as xyl, dibutyl maleate, getyl fumarate, and dibutyl itaconate; (meth) acrylic acid, maleic acid, fumaric acid, monoethyl maleate, monobutyl fumarate, etc. Lenic unsaturated carboxylic acid monomers; ethylenically unsaturated nitrile monomers such as (meth) acrylonitrile; vinyl chloride, vinyl acetate, etc. That.

The method for producing the conjugated rubbers (A) and (B) used in the present invention is not particularly limited, but an emulsion polymerization method or a solution polymerization method can be adopted. Solution polymerization is a conjugate It can be preferably used when preparing a rubber having a vinyl bond content of 20 to 85% by weight in a conjugated gen unit in a rubber.

As the emulsion polymerization method, a conventional emulsion polymerization method may be used.For example, a method in which a predetermined amount of the above monomer is emulsified and dispersed in a dispersion medium in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator is employed. Can be The amount of each monomer used is appropriately selected so that each monomer unit has a desired content.

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

Water is usually used as a dispersion medium used in the emulsion polymerization, and may contain a water-soluble organic solvent such as methanol or ethanol as long as the stability during polymerization is not impaired.

Examples of the radical polymerization initiator include a persulfate such as ammonium persulfate and potassium persulfate; a combination of ammonium persulfate and ferric sulfate; a combination of an organic peroxide and ferric sulfate; Redox initiators such as a combination of hydrogen oxide and ferric sulfate; and the like.

In order to adjust the viscosity of the obtained rubber, a chain transfer agent may be added. Examples of the chain transfer agent include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, carbon tetrachloride, thioglycolic acid, diterpene, terpinolene, r-terbinene, α-methylstyrene dimer and the like. Can be

The temperature of the emulsion polymerization can be appropriately selected depending on the type of the radical polymerization initiator to be used, but is usually 0 to 100 ° C, preferably 0 to 60 ° C. The polymerization mode may be any mode such as continuous polymerization or batch polymerization.

From the viewpoint of preventing the gelation of the polymer, the polymerization conversion rate at the time of stopping the polymerization reaction is preferably 85 <85 or less, more preferably 50-75 50. Termination of the polymerization reaction is usually performed by adding a polymerization terminator to the polymerization system when a predetermined polymerization conversion is reached. Examples of the polymerization terminator include amine-based compounds such as isopropylhydroxylamine and getylhydroxylamine-hydroxylamine. Compounds; quinone-based compounds such as hydroquinone and benzoquinone; sodium nitrite, sodium dithiocarbamate and the like.

After termination of the polymerization reaction, an antioxidant may be added to the obtained latex, if necessary.

After the polymerization reaction is stopped, unreacted monomers are removed from the obtained latex as necessary, and then salts such as sodium chloride, calcium chloride and potassium chloride are used as a coagulant, and nitric acid, sulfuric acid and the like are used as necessary. The acid can be added to adjust the pH of the coagulation system to a predetermined value while coagulating the polymer as crumb, and then separating the dispersion medium to recover the polymer. The crumb can be washed and dehydrated and then dried with a band dryer or the like to obtain the desired geno rubber. At the time of coagulation, if desired, a latex and an extender oil which has been previously made into an emulsified dispersion can be mixed and recovered as an oil-extended rubber.

The solution polymerization method may be a conventional solution polymerization method.For example, the above monomer is polymerized in a polymerization solvent using an organic alkali metal as an anion polymerization catalyst, if desired, in the presence of a polar compound. .

Examples of the polymerization solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; alicyclic rings such as cyclopentane, cyclohexane, and methylcyclopentane. Formula hydrocarbons; aromatic hydrocarbons such as benzene and toluene; and the like. If necessary, unsaturated hydrocarbons having low anion polymerizability such as 1-butene, cis-1-butene, and 2-hexene may be used in combination. These polymerization solvents are used alone or in combination of two or more kinds, and are usually used in a ratio such that the monomer concentration becomes 1% by weight to 40% by weight 0/0.

Examples of the organic alkali metal 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 and potassium naphthalene; Of these, organic lithium compounds are preferred, and organic monolithium compounds are particularly preferred. These organic alkali metals can be used alone or in combination of two or more. The amount of organic alkali metal used depends on the required polymer Although it is appropriately selected depending on the molecular weight, it is usually in the range of 0.1 to 30 mmol, preferably 0.2 to 15 mmol, more preferably 0.3 to 1 Ommol per 100 g of monomer. is there.

The organic alkali metal may be used as an organic alkali metal amide by previously reacting with a secondary amine such as dibutylamine, dihexylamine or dibenzylamine.

When an organic alkali metal is used as a polymerization catalyst, it is preferable not to use such a monomer since there are monomers that affect the polymerization reaction. From this point of view, it is preferable to use a tertiary amino group-containing monomer as the amino group-containing monomer, and it is particularly preferable to use an N, N-disubstituted amino aromatic vinyl compound. Dimethylaminoethylstyrene is most preferred.

The polar compound is not particularly limited as long as it is a compound generally used in anion polymerization to adjust the microstructure of conjugated gen units and the distribution of aromatic vinyl in the copolymer chain. Specific examples thereof include ether compounds such as dibutyl ether, tetrahydrofuran, and ethylene glycol ethyl ether; tertiary amines such as trimethylethylenediamine and trimethylamine; potassium mono-t-amyloxide; Alkali metal alkoxides such as amyloxide; phosphine compounds such as triphenylphosphine; and the like. Among these, tertiary amines are preferred, and tetramethylethylenediamine is particularly preferred, in that the amount of vinyl bonds in the conjugated gen unit and the amount of independent bond units of aromatic vinyl can be greatly increased.

The amount of the polar compound used is preferably in the range of 0.1 to 100 mol, more preferably 0.5 to 50 mol, and particularly preferably 1 to 30 mol, per 1 mol of the organic alkali metal used as the polymerization initiator. It is. Within this range, the amount of vinyl bonds in the conjugated gen unit can be adjusted appropriately.

The polymerization reaction is usually carried out at a temperature in the range of 170 to 150 ° C, preferably 0 to 100 ° C, and more preferably 30 to 90 ° C, in a batch or continuous polymerization mode. When the aromatic vinyl monomer is copolymerized, the composition ratio of the aromatic vinyl monomer and the conjugated gen in the polymerization system is improved in order to improve the randomness of the bond between the aromatic vinyl monomer units. It is preferable to supply the conjugated gen or a mixture of the conjugated gen and the aromatic vinyl monomer continuously or intermittently to the reaction system so that the content of the aromatic vinyl monomer is in a specific concentration range. . After the completion of the polymerization reaction, an alcohol such as methanol or isopropanol is added as a polymerization terminator to terminate the reaction to obtain a polymerization solution. Before adding the polymerization terminator, tin tetrachloride, tetrachlorosilane, tetramethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylenediisocyanate, which can react with the polymerization active terminal And a polymerization terminal modifier such as 4,4′-bis (getylamino) benzophenone, N-methylpyrrolidone, and N-vinylpyrrolidone.

Next, if desired, after adding an antioxidant or a crumbing agent to the polymerization solution, the polymerization solvent is separated from the polymerization solution by direct drying or steam stripping, and the target rubber is recovered. Before separating the polymerization solvent from the polymerization solution, the extension oil and the polymerization solution may be mixed in advance and recovered as an oil-extended rubber.

The rubber composition of the present invention is prepared by kneading and blending a conjugated rubber (A) and a conjugated rubber (B) in the form of a solid rubber, respectively, or as a solid rubber. After mixing the conjugated rubber (A) latex or solution and the conjugated rubber (B) latex or solution, the dispersion medium is separated and obtained as a solid rubber-like blend. Is also good. Among them, the latter method is preferable because the dispersibility of the conjugated rubber (A) and the conjugated rubber (B) is excellent, and it is particularly preferable to mix the latexes or the solutions. Here, the dispersion medium is mainly composed of water in the case of latex, and is mainly composed of the polymerization solvent in the case of solution.

The rubber composition of the present invention preferably contains an extension oil so that the viscosity of the compound when silica is compounded does not become too high. As the extender oil, those commonly used in the rubber industry can be used, and examples thereof include a paraffin extender oil, an aromatic extender oil, and a naphthenic extender oil.

The pour point of the extender oil is preferably between 20 and 50 ° C, more preferably between 10 and 30 ° C. Within this range, the extensibility and the balance between tensile properties and low heat build-up are excellent. The aroma carbon content (CA%) of the extended oil by Kurz analysis is preferably 15% or more, more preferably 25% or more, and the paraffin carbon content (CP%) is preferably 65% or less, more preferably Preferably it is 45%. If CAo / o is too small or CP% is too large, the tensile properties will be insufficient. The polycyclic aromatic content of the extender oil is preferred. Or less than 3%. This content is measured by the method of IP346 (test method of THE INSTITUTE PETROLEUM in the UK).

The content of the extender oil is preferably 5 to 100 parts by weight, more preferably 10 to 80 parts by weight, based on 100 parts by weight of the total of the conjugated rubber (A) and the conjugated rubber (B). Preferably it is 20 to 60 parts by weight. When the content of the extender oil is in this range, the viscosity of the compound containing silicide is appropriate, and the tensile properties and the low heat generation balance are excellent.

When compounding an extender oil, it is possible to mix the polymer latex or solution at a predetermined ratio in advance with each polymer latex or solution before obtaining as a solid rubber, and then obtain as an oil-extended rubber. It is preferable because it has excellent dispersibility.

The rubber composition of the present invention preferably contains at least one selected from silicic acid and carbon black as a reinforcing agent, and more preferably contains silica as an essential component. As a reinforcing agent, a carbon-silica dual 'phase' filler having silica supported on the carbon black surface may be used.

Examples of the silica include dry-process white carbon, wet-process white carbon, colloidal silica, and precipitated silica disclosed in JP-A-62-62838. Among these, wet-process white carbon containing hydrous gay acid as a main component is particularly preferable. These silicas can be used alone or in combination of two or more.

The specific surface area of silica is not particularly limited, a nitrogen adsorption specific surface area (BET method) is preferably from 5O ~ 400m ² Zg, more preferably 100~220m ² Zg, particularly preferably 12 0~190m ² Zg . When the specific surface area of the silica is in this range, the balance between the tensile properties and the low heat buildup is excellent. The nitrogen adsorption specific surface area is a value measured by the BET method according to ASTMD3037-81.

As carbon black, for example, furnace black, acetylene black, thermal black, channel black, graphite and the like can be used. Among them, furnace black is particularly preferred, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, and FEF. Grade grades. These carbon blacks can be used alone or in combination of two or more.

The specific surface area of carbon black is not particularly limited, a nitrogen absorption specific surface area (N ₂ SA), preferably 5 ~ 200m ² Zg, more preferably 50m~ 150m ² Zg, particularly preferably 80~130m ² Zg is there. When the nitrogen adsorption specific surface area is in this range, the tensile characteristics are more excellent.

Also, the adsorption amount of dibutylphthalate (KDBP) of the power pump rack is not particularly limited, and the power is preferably 5 to 300 ml 1 OOg, more preferably 50 to 200 ml / 1 OOg, and particularly preferably 80 to "! 60 ml / 100 g When the DBP adsorption amount is within this range, the tensile properties are more excellent.

Further, as a carbon black, the adsorption (CTAB) specific surface area of cetyltrimethylammonium bromide disclosed in JP-A-5-230290 is 110 to 170 m ² Zg, and at a pressure of 24, OOOpsi. Abrasion resistance can be improved by using high-structure one-strength black, which has a DBP (24M4D BP) oil absorption of 110-130mlZ100g after repeated compression.

The compounding amount of the reinforcing agent is preferably 10 to 200 parts by weight, more preferably 20 to "! 50 parts by weight, particularly preferably 30 to"! 20 parts by weight. When silica and carbon black are used in combination as a reinforcing agent, the mixing ratio is preferably 10:90 to 99: 1, more preferably 30:70 to 95: 5, by weight ratio of silica: force—bon black, It is preferably 50:50 to 90:10 for temples.

When the rubber composition of the present invention contains silica as a reinforcing agent, it is preferable to add a silane coupling agent for the purpose of further improving tensile properties and low heat build-up.

Examples of the silane coupling agent include vinyltriethoxysilane,-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, Ν- (monoaminoethyl) _-r- aminopropyl trimethoxysilane, (3- (triethoxysilyl) propyl) tetrasulfide, bis (3- (triethoxysilyl) propyl) disulphide and the like, and r-trimethoxysilylpropyl dimethylthiothiol described in JP-A-6-248116 Lubamil tetrasulfide, 7-trimethoxysilylpropylbenzothiazyltetrasulfide And the like. Since scorch at the time of kneading can be avoided, the silane coupling agent is preferably one containing four or less sulfur in one molecule. These silane coupling agents can be used alone or in combination of two or more.

The amount of the silane coupling agent to be added is preferably 0.1 to 30 parts by weight, more preferably "! To 20 parts by weight, particularly preferably 2 to 10 parts by weight, based on 100 parts by weight of silica. .

The rubber composition of the present invention may contain other rubbers other than the conjugated rubber (A) and the conjugated rubber (B) as long as the effects of the present invention are not substantially impaired. Examples of other rubbers include natural rubber, high cis-polyisoprene rubber, high cis-polybutadiene rubber, acrylonitrile-butadiene copolymer rubber, butyl rubber, and ethylene-propylene-one-gen copolymer rubber.

The rubber composition of the present invention contains, in addition to the above components, compounding agents such as a crosslinking agent, a crosslinking accelerator, a crosslinking activator, an antioxidant, an activator, a plasticizer, a lubricant, and a filler according to a conventional method. Each of them can be contained in a required amount.

Examples of the cross-linking agent include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur; sulfur halides such as sulfur monochloride and sulfur dichloride; dicumyl valoxide, tert-butyl butyl oxide. Quinonedioximes such as P-quinondioxime, p, p'-dibenzoylquinonedioxime; triethylenepentramine, hexamethylenediamine powerbamate, 4,4'-methylenebis-o-chloroa Organic polyamine compounds such as diphosphorus; alkylpheno having a methylol group

—Resin resin; and the like. Among these, sulfur is preferred, and powdered sulfur is particularly preferred. These crosslinking agents may be used alone or in combination of two or more. The compounding amount of the crosslinking agent is preferably 0.3 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the rubber component.

Examples of the crosslinking accelerator include N-cyclohexyl-1-benzothiazolesulfenamide, Nt-butyl-2-benzothiazolsulfenamide, N-oxyethylene-12-benzothiazolsulfenamide, and N-oxyethylene 2-benzothiazolsulfenamide, N, N'-diisopropyl-1-benzothiazolesulfenamide, etc. Sulfenamide-based crosslinking accelerators: guanidine-based crosslinking accelerators such as diphenylguanidine, dioritoltriguanidine, and o-tolylbiguanidine; thioperia-based crosslinking accelerators such as getylthioperia; 2-mercaptobenzothiazole Thiazole-based cross-linking accelerators such as dimethyl, dibenzothiazyl disulfide and 2-mercaptobenzothiazol zinc salt; thiuram-based cross-linking accelerators such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; Cross-linking accelerators such as sodium rubamate and dithiol-rubic acid-based cross-linking accelerators such as getyldithi-rich zinc rubamate; sodium xanthate-based cross-linking accelerators such as sodium isopropylxanthate, zinc isopropylxanthate and zinc butylxanthate; Agent It is. Among them, sulfenamide-based crosslinking accelerators are preferred. These cross-linking accelerators are used alone or in combination of two or more. The compounding amount of the crosslinking accelerator is preferably from 0.3 to 10 parts by weight, more preferably from 0.5 to 5 parts by weight, based on 100 parts by weight of the rubber component.

As the crosslinking activator, for example, higher fatty acids such as stearic acid, zinc oxide, and the like can be used. It is preferable to use zinc oxide having a surface activity of 5 m or less as the zinc oxide, and it is preferable to use active zinc white having a particle size of 0.05 to 0.2 jum or zinc white having a particle size of 0.3 to 1 μm. Can be mentioned. Zinc oxide may be surface-treated with an amine-based dispersant or wetting agent. These crosslinking activators can be used alone or in combination of two or more. The mixing ratio of the crosslinking activator is appropriately selected depending on the type of the crosslinking activator. The blending amount of the higher fatty acid is preferably from 0.3 to 10 parts by weight, more preferably from 0.5 to 5 parts by weight, based on 100 parts by weight of the rubber component. The amount of zinc oxide is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the rubber component.

Further, examples of the compounding agent include an activator such as diethylene glycol, polyethylene glycol, and silicone oil; a filler such as calcium carbonate, talc, clay, and aluminum hydroxide; and a wax.

The rubber composition containing a reinforcing agent can be obtained by kneading each component according to a conventional method. For example, after kneading a compounding agent excluding a crosslinking agent and a crosslinking accelerator, a reinforcing agent, and a rubber component, a kneading product may be kneaded with a crosslinking agent and a crosslinking accelerator to obtain a rubber composition. it can. The kneading temperature of the compounding agent, the reinforcing agent, and the rubber component excluding the crosslinking agent and the crosslinking accelerator is preferably 80 to 200 ° C, more preferably 100 to 190 ° C, and particularly preferably 140 to 180 ° C. And Next, after cooling the obtained kneaded product to preferably 100 ° C. or less, more preferably 80 ° C. or less, it is kneaded with a crosslinking agent and a crosslinking accelerator.

In addition, the rubber composition containing the reinforcing agent is obtained as a wet master batch rubber by mixing a reinforcing agent at a predetermined ratio in advance into each polymer latex or polymer solution before obtaining as a solid rubber. You can also.

The rubber composition of the present invention is usually used after crosslinking. The crosslinking method is not particularly limited, and may be selected according to the shape, size, and the like of the crosslinked product. By filling the mold with the crosslinkable rubber composition and heating, the crosslinkable rubber composition which has been molded in advance or which can be crosslinked at the same time as molding may be heated and crosslinked. The crosslinking temperature and the crosslinking time are also not particularly limited, and may be selected according to the shape and size of the crosslinked product. The crosslinking temperature is preferably from 120 to 200 ° C, more preferably from 140 to 180 ° C.

(Example)

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples. Parts and% in Examples and Comparative Examples are based on weight unless otherwise specified.

The properties of the copolymer and the rubber composition were measured according to the following methods.

(1) Styrene unit amount in copolymer: Measured according to JIS K6383 (refractive index method).

(2) Amount of vinyl bond unit in butadiene part in copolymer: 500 MHz ^{1 1—} ΝΜ Measured with R, and shown as the amount of vinyl bond unit to the whole polymer.

(3) Amino group-containing monomer unit in the copolymer: The copolymer is dissolved in tetrahydrofuran, reprecipitated twice with a mixed solvent of methanol / acetone (11 volume ratio), and dried under vacuum. After that, measurement was performed by 500 MHz ¹ H-NMR.

(4) Mooney viscosity of copolymer rubber (ML, ₊₄ , 100 ° C): Measured according to JIS K6300. (5) Tensile properties of crosslinked rubber: The stress at 300% elongation (MPa) was measured according to JIS K6301. This property was expressed as an index (tensile property index) with the reference sample as 100. The larger the value, the better.

(6) Low heat build-up of crosslinked rubber: RDA-II manufactured by Rheometrics Co., Ltd. was used to measure 3 <5 at 60 °° under 0.50 / 0 torsion and 201> ^. This characteristic is indicated by an index (low exothermic index) with the reference sample as 100. The larger the value, the better.

(7) Processability of rubber composition: After kneading the rolls, observe the sheet-shaped sample taken out so that the thickness of the sheet becomes 3 mm, and check the smoothness of the surface skin and the continuity of the edge portion of the sheet. It was scored based on the following criteria, and judged by the total score. The larger the total score, the better the workability. If the score is 5 or more, no problems occur in the later stages such as the green tire molding process.

Surface skin smoothness

4 points: The surface is smooth and shiny.

3 points: The surface is almost smooth but not glossy.

2 points: There are irregularities.

1 point: There are many irregularities and the depth of the irregularities is deep.

Edge continuity 4 points: Smooth.

3 points: There are a few irregularities.

2 points: Many irregularities.

1 point: There are many deep cuts.

(Production Example 1)

200 parts of deionized water, 1.5 parts of rosinite test, 2.1 parts of fatty acid stone, 0.13 parts of monomer and t-dodecylmercaptan having the composition shown in Table 1 in a pressure-resistant reactor equipped with a stirrer Was charged. At a reactor temperature of 10 ° C, 0.1 parts of diisopropylbenzene hydride peroxide as polymerization initiator, 5 parts of a deionized aqueous solution in which 0.2 parts of sodium 'formaldehyde' sulfoxylate were dissolved, and sodium ethylenediaminetetraacetate 2 parts of a deionized aqueous solution in which 0.004 parts of ferric sulfate and 0.04 parts of ferric sulfate were dissolved were added to the reactor to initiate polymerization. When the polymerization conversion reaches 450/0, t_dodecylmel force The reaction was continued by adding 0.05 parts of butane. When the polymerization conversion reached 700/0, 0.05 parts of getylhydroxylamine was added to stop the reaction.

After removing unreacted monomers by steam distillation, 100 parts of the polymer was treated with 0.8 parts of octadecyl-13- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate as an antioxidant in an amount of 0.8 parts. And 0.2 part of 2,4-bis (n-octylthiomethyl) -1-methylphenol were added to obtain a polymer latex containing a polymer H1.

A part thereof was taken out, and the polymer latex was coagulated with sodium chloride while adjusting the pH to 3 to 5 with sulfuric acid to obtain a crumb-like polymer. The crumb was dried with a hot air dryer at 80 ° C. to obtain a solid rubber. Table 1 shows the composition and viscosity of the obtained rubber.

(Production Examples 2-6)

Production Example 1 was repeated except that the monomer was changed to the charge composition shown in Table 1, and the amount of t-dodecyl mercaptan used was changed appropriately so that the Mooney viscosity of the obtained solid rubber became the value shown in Table 1. Polymerization was carried out in the same manner to obtain polymer latexes containing polymers HA1, L1 and LA1 to A3, respectively.

A solid rubber was prepared in the same manner as in Production Example 1. Table 1 shows the composition and muci-viscosity of each solid rubber.

Production example '' 1 2 3 4 5 6 Polymer No. H 1 H A 1 to 1 A 1 L A 2 to A 3 Preparation amount (parts)

1, 3-butadiene 57.5 56.3 57.5 56.3 55.7 55.5 Styrene 42.5 42.5 42.5 42.5 42.5 42.5

N, 'N-dimethylaminopropyl acrylamide 1.2.2.1.1.8 I * N. N-dimethylaminoethylstyrene 2 polymer composition (%)

Styrene unit 35.5 35.0 34.9 34.8 35.3 35.0

N, N—Dimethylaminopropylacrylamide unit 0.7 0.

N, N-Dimethylaminoethylstyrene unit 1.16 viscosity 1 22 1 20 70 67 54 7 6

(Example 1)

After mixing the polymer latex containing the polymer H1 and the polymer latex containing the polymer latex LA1 such that the ratio of each polymer is as shown in Table 2, に対して was added to 100 parts of the total polymer. 37.5 parts of Enerthenel 849A (manufactured by Pretty Petroleum) was added as an exhibition oil. Thereafter, the polymer latex containing the extended oil was coagulated with sodium chloride while adjusting the pH to 3 to 5 with sulfuric acid to obtain a crumb-like solid. The crumb was dried with a hot air dryer at 80 ° C to obtain an oil-extended rubber. Table 2 shows the Mooney viscosity of the obtained oil-extended rubber.

Using a Brabender type mixer, 137.5 parts of the above oil-extended rubber (equivalent to 100 parts of rubber) was masticated at a starting temperature of 110 ° C for 30 seconds, and then silica (Zeosil 1165 MP: manufactured by Rhodia) 53 parts and silane coupling agent (Si69: manufactured by Degussa) 6. 4 parts were charged and kneaded for 2 minutes. Then, 27 parts of silica (Zeosil 1165MP: manufactured by Rhodia) 27 parts, zinc oxide (particle size 0.4 m, zinc Hana # 1: Honjo Chemical Co., Ltd.) 3 parts, stearic acid 2 parts, and antioxidant (Nocrack 6C: Ouchi Shinko Co., Ltd.) 2 parts were added and kneaded for 2 minutes. The temperature at the end of the mixing was 150 ° C.

The obtained kneaded product was combined with 1.4 parts of sulfur and a crosslinking accelerator (a mixture of 1.8 parts of N-cyclohexyl-2-benzothiazylsulfenamide and 1.7 parts of diphenylguanidine). After kneading with an open roll at 50 ° C., the mixture was taken out in a sheet form.

The workability was evaluated by observing the surface skin and the edge portion of the above sheet. Table 2 shows the results.

The physical properties of the crosslinked rubber were determined by press-crosslinking at 160 ° C for 30 minutes to prepare test specimens, and each physical property was measured. Table 2 shows the results. However, in Table 2, it was expressed using Comparative Example 2 as a reference (index 100).

(Examples 2 and 3)

An oil-extended rubber was prepared in the same manner as in Example 1, except that the mixing ratio was changed to the polymer shown in Table 2. Table 2 shows the Mooney viscosity of each oil-extended rubber.

A rubber composition was prepared and processed in the same manner as in Example 1 except that the obtained oil-extended rubber was used, and the physical properties of the crosslinked rubber were evaluated. The results are shown in Table 2. (Example 4)

To a polymer latex containing the polymer H1, 37.5 parts of Enerthenel 849A (manufactured by Pretty Petroleum Co., Ltd.) was added as extender oil to 100 parts of the polymer!]. Thereafter, the polymer latex containing the extended oil was coagulated with sodium chloride while adjusting the pH to 3 to 5 with sulfuric acid to obtain a crumb-like solid. The crumb was dried with a hot air dryer at 80 ° C to obtain an oil-extended rubber.

To a polymer latex containing the polymer LA1, 37.5 parts of Enerthenel 849A (manufactured by British Petroleum Co.) was added as an extender oil to 100 parts of the polymer. Thereafter, the same procedure as above was performed to obtain an oil-extended rubber.

A rubber composition was prepared in the same manner as in Example 1 except that the oil-extended rubber containing the polymer H1 and the oil-extended rubber containing the polymer LA1 were used so that the ratios shown in Table 2 were obtained. The processability was evaluated, and further the physical properties of the crosslinked rubber were evaluated. Table 2 shows the results.

(Comparative Example 1)

To a polymer latex containing polymer HI, 37.5 parts of Enerthenel 849A (manufactured by Pretty Petroleum Co.) was applied as an extension oil to 100 parts of the polymer; Thereafter, the polymer latex containing the extended oil was coagulated with sodium chloride while adjusting the pH to 3 to 5 with sulfuric acid to obtain a crumb-like solid. The crumb was dried with a hot air dryer at 80 ° C to obtain an oil-extended rubber.

Except for using this oil-extended rubber, a rubber composition was prepared and its processability was evaluated in the same manner as in Example 1, and further the physical properties of the crosslinked rubber were evaluated. Table 2 shows the results.

(Comparative Example 2)

A rubber composition was prepared and its processability was evaluated in the same manner as in Comparative Example 1 except that the polymer H1 was changed to the polymer LA1, and further, the physical properties of the crosslinked rubber were evaluated. Table 2 shows the results.

(Comparative Examples 3 and 4)

A rubber composition was prepared and the processability thereof was evaluated in the same manner as in Example 1 except that the polymer and the compounding ratio were changed as shown in Table 2, and further, the physical properties of the crosslinked rubber were evaluated. Table 2 shows the results. Comparative Example ''

1 2 3 4 1 L 3 4 ri P * H 1 H 1 Η 1 Η .1 H 1 Η 1 し 1

50 50 50 60 1 U U 50 50 R A 1 L A 2 L A 3 L A 1 Η A 1 Η A 1

5C DP; 50 5 D D 40 1 00 50 50 Extending oil volume (parts) 3 7.5 57.5 57.5 -.37.5 37.5 57.5 537.5 37.5

6 Oil s After viscosity 22 42 47 57 34 56 4 Physical properties of rubber composition

'Sheet skin (dots) 3 2 2 3 3 1 1 2 Sheet edge (dots). 4 4 3 4 4 1 1 2 Workability (dots) 7 6 5 f 7 2 2 4 One viscosity 86 88 92 8 1 7 7 90 9 1 83

Stress at 300% elongation (index) 88 1 00 1 02 94

1 05 1 05 1 04 03

tan <5 (index) 1 05 1 1 2 1 1 0 04 90 1 00 1 02 96

The rubber composition of Comparative Example 1 containing only the polymer H1 having no amino group has good processability, but is inferior in the properties of the crosslinked rubber. The rubber composition of Comparative Example 2 containing only the polymer LA1 having an amino group is superior to Comparative Example 1 in the properties of the crosslinked rubber, but is inferior in processability. The rubber composition of Comparative Example 3 blended with a polymer H1 having no amino group and a polymer HA1 having an amino group but having a difference in viscosity of less than the range specified in the present invention is: The properties of the crosslinked rubber are good, but the processability is poor. The rubber composition of Comparative Example 4 in which the polymer L1 having no amino group and the polymer HA1 having an amino group having a higher viscosity than that of the polymer L1 were blended, the processability was poor, and the rubber composition of the crosslinked rubber was poor. Poor characteristics.

Compared with these comparative examples, the rubber compositions containing silica of Examples 1 to 4 of the present invention have good processability and excellent properties of crosslinked rubber.

(Production Example 7)

In an autoclave equipped with a stirrer, 4,000 parts of cyclohexane, 270 parts of styrene, 330 parts of 1,3-butadiene and 0.3 parts of tetramethylethylenediamine were charged, and 0.25 parts of n-butyllithium was added, and the mixture was added at 40 ° C. To initiate polymerization. Twenty minutes after the start of the polymerization, the remaining mixture of 80 parts of styrene and 320 parts of 1,3-butadiene was continuously added over 60 minutes, and after confirming that the polymerization conversion reached 100%, 1,3 — 5 parts of butadiene was added and reacted for 10 minutes, then 0.11 parts of tetramethoxysilane was added and reacted for 30 minutes, and methanol was added to stop the reaction. The highest temperature reached during polymerization was 65 ° C.

0.2 part of 2,4-bis (n-octylthiomethyl) -6-methylphenol as an antioxidant was added to 100 parts of the obtained polymer solution per 100 parts of polymer, and the polymer SH1 was added. A polymer solution was obtained.

A part thereof was taken out, and after removing the polymerization solvent by a steam stripping method, dewatered by a roll, and further dried by a hot air drier at 80 ° C to obtain a solid rubber. Table 3 shows the composition of the solid rubber and its viscosity.

(Production Examples 8 to 10)

A polymer solution containing polymers SHA1, SL1, and SLA1, respectively, was obtained in the same manner as in Production Example 7, except that the monomer charge composition and the coupling agent were changed as shown in Table 3. Table 3 shows the composition and Mooney viscosity of each polymer. Table 3

(Example 5)

The polymer solution containing the polymer SH1 and the polymer solution containing the polymer SLA1 were mixed so that each polymer had the compounding ratio shown in Table 4, and then, based on 100 parts of the whole polymer, w extended oil was added. Enerthenel 849 A (British Petroleum) as 37/5 Added. The polymerization solvent was separated and removed from the polymer solution containing the extended oil by a steam stripping method, dewatered by a roll, and further dried by a hot air dryer at 80 ° C to obtain an oil-extended rubber. Table 4 shows the Mooney viscosity of the oil-extended rubber.

Using a Brabender type mixer, 137.5 parts of the above oil-extended rubber (equivalent to 100 parts of rubber) was masticated at a starting temperature of 110 ° C for 30 seconds, and then silica (Zeosil 1200 MP: Kuchiichidia Co., Ltd.) 53 parts and 8 parts of silane coupling agent (Si69: Degussa) were added and kneaded for 2 minutes, and then 27 parts of silica (Zeosil 1200M P: Kuchiichidia), Enerthenel 849A (British Petroleum) 7.5 parts, Siriya | | ($ ί [degree 0.4 μm, zinc flower # 1: Honjo Chemical Co., Ltd.) 3 parts, stearic acid 2 parts, and antioxidant (Nocrack 6C: Ouchi Emerging 2 parts) and kneaded for 2 minutes. The temperature at the end of the mixing was 150 ° C.

The obtained kneaded material was combined with 1.4 parts of sulfur and a crosslinking accelerator (a mixture of 1.8 parts of N-cyclohexyl-2-benzothiazylsulfenamide and 1.9 parts of diphenylguanidine). After kneading with an open roll at 50 ° C., the mixture was taken out in a sheet form.

The workability was evaluated by observing the surface skin and the edge portion of the above sheet. Table 4 shows the results.

The physical properties of the crosslinked rubber were determined by press-crosslinking at 160 ° C for 30 minutes to prepare test specimens, and each physical property was measured. Table 4 shows the results. However, in Table 4, Comparative Example 6 was described as a reference (index 100).

(Comparative Example 5)

To a polymer solution containing the polymer SH1 was added 37.5 parts of Enerthenel 849A (manufactured by British Petroleum Corp.) as an extension oil per 100 parts of the polymer. After removing the polymerization solvent from the polymer solution containing the extended oil by a steam stripping method, the polymer solution was rolled and dehydrated, and further dried by a hot air drier at 80 ° C to obtain an oil-extended rubber. Table 4 shows the viscosity of the oil-extended rubber.

Except for using the above oil-extended rubber, a rubber composition was prepared and its processability was evaluated in the same manner as in Example 5, and further, the physical properties of the crosslinked rubber were evaluated. Table 2 shows the results.

(Comparative Example 6)

Instead of a polymer solution containing polymer SH1, a polymer solution containing polymer SLA1 was used. A rubber composition was prepared and its processability was evaluated in the same manner as in Comparative Example 5, except for using the rubber composition, and further, the physical properties of the crosslinked rubber were evaluated. Table 2 shows the results.

(Comparative Examples and 8)

A rubber composition was prepared and its processability was evaluated in the same manner as in Example 5, except that the polymers and the compounding ratio shown in Table 4 were used, and the physical properties of the crosslinked rubber were evaluated. Table 2 shows the results.

Table 4

Table 4 shows the following.

The rubber composition of Comparative Example 5 containing only the polymer SH1 having no amino group had good processability but was inferior in the properties of the crosslinked rubber. The rubber composition of Comparative Example 6, which contains only the polymer SLA1 having an amino group, is superior to Comparative Example 5 in the properties of the crosslinked rubber, but is inferior in processability. A rubber composition of Comparative Example 7 in which a polymer SH 1 having no amino group and a polymer SHA 1 having an amino group but having a difference in Mooney viscosity smaller than the range specified in the present invention are blended. Is inferior in processability and inferior in properties of crosslinked rubber. The rubber composition of Comparative Example 8 in which a polymer SL 1 having no amino group and a polymer S HA 1 having an amino group having a higher viscosity than that of the polymer SL 1 were blended has poor processability, and Poor properties of crosslinked rubber.

Compared with these comparative examples, the rubber composition containing the silica of Example 5 within the range specified by the present invention has good processability and excellent properties of the crosslinked rubber. Industrial applicability

The rubber composition of the present invention is excellent in the surface shape of a sheet when a compound containing silica as a reinforcing agent is formed into a sheet by a roll, and is excellent in tensile properties and low heat generation.

Accordingly, the rubber composition of the present invention can be used in various applications that make use of its properties, for example, tire members such as treads, under treads, force scums, sidewalls, bead portions; hoses, window frames, belts, shoes. It can be used for rubber materials such as bases, anti-vibration rubber, seismic isolation rubber, and automotive parts; resin-reinforced rubber materials such as impact-resistant polystyrene and ABS resin. Among them, it is suitable as a tire member and particularly suitable as a tire tread of a fuel-efficient tire.

Claims

The scope of the claims

1. Containing 40 to 100% by weight of a conjugated diene unit, 0 to 60% by weight of an aromatic vinyl monomer unit and 0 to 20% by weight of other copolymerizable monomer units, and has a Mooney viscosity of 70 to 200. 20 to 80 parts by weight of a conjugated diene rubber (A) in the range of 40 to 99.8 parts by weight ⁰ / o, an aromatic vinyl monomer unit 0 to 59.8 parts by weight, and an amino group Containing 0.2 to 20% by weight of monomer units and 0 to 20% by weight of other copolymerizable monomers, having a viscosity of 20 to 150, Containing 80 to 20 parts by weight of a conjugated diene rubber (B) having a muddy viscosity of 10 or more lower than the muddy viscosity of the base rubber (A) (conjugated diene rubber (A) and conjugated diene rubber (B ) And is 100 parts by weight in total.)

2. 50 to 90% by weight of conjugated gen unit, 10 to 50% by weight of aromatic vinyl monomer unit, and 0 to 10% by weight of other copolymerizable monomer unit when conjugated gen-based rubber (A) is used %. .

3. The rubber composition according to claim 1, wherein the conjugated rubber (A) does not contain an amino group-containing monomer unit or contains less than 0.2% by weight. .

4. The rubber composition according to any one of claims 1 to 3, wherein the conjugated diene rubber (A) has a viscosity of 90 to 160. .

5. The conjugated gen-based rubber (B) is composed of 50 to 89.7% by weight of a conjugated unit, 10 to 49.7% by weight of an aromatic vinyl monomer unit, and 0.3 to 4% by weight of an amino group-containing monomer unit. The rubber composition according to any one of claims 1 to 4, comprising 10% by weight and 0 to 10% by weight of a unit of another copolymerizable monomer. .

6. The conjugated diene rubber (B) has a viscosity in the range of 40 to 130, which is 20 or more lower than the muddy viscosity of the synergistic rubber (A). 6. The rubber composition according to any one of 1 to 5. .

7. The ratio of the conjugated rubber (A) and the conjugated rubber (B) is 30 to 75 parts by weight of the conjugated rubber (A) and the conjugated rubber (B) in a total amount of 100 parts by weight. B) The rubber composition according to any one of claims 1 to 6, which is 25 to 70 parts by weight.

8. The amino group-containing monomer unit is derived from at least one amino group-containing polymerizable monomer selected from primary, secondary and tertiary amino groups. 8. The rubber composition according to any one of items 1 to 7.

9. When the amino group-containing monomer unit is N, N-disubstituted aminoalkyl monoacrylate and monomethacrylate, N, N-disubstituted aminoalkyl-acrylamide and monomethacrylamide, N, N-disubstituted amino aromatic 8. The method according to claim 1, which is derived from at least one tertiary amino group-containing polymerizable monomer selected from a vinyl compound and a polymerizable monomer having a pyridyl group. Rubber composition.

10. The method according to any one of claims 1 to 9, further comprising 5 to 100 parts by weight of an extension oil based on 100 parts by weight of the total of the conjugated rubber (A) and the conjugated rubber (B). The rubber composition described.

11. Prepared by mixing the conjugated rubber (A) and the conjugated rubber (B) with the respective copolymer latex or solution and the extension oil before obtaining the conjugated rubber (B) as a solid rubber. 11. The rubber composition according to claim 10.

12. Furthermore, for 100 parts by weight of the total of the conjugated rubber (A) and the conjugated rubber (B), at least one reinforcing agent selected from silica and bonbon black is added in an amount of 10 to 200 parts by weight. 12. The rubber composition according to any one of claims 1 to 11, comprising parts by weight.

13. The rubber composition according to claim 12, wherein the rubber composition is silica having a nitrogen adsorption specific surface area (BET method) of 50 to 400 m ² Zg.

14. The rubber composition according to claim 12, wherein the rubber composition is a mixture containing silica and carbon black at a silica Z carbon black weight ratio of 1090 to 99: 1.

15. The rubber composition according to claim 13, further comprising 0.1 to 30 parts by weight of a silane coupling agent with respect to 100 parts by weight of silica.

16. A latex or solution of the conjugated rubber (A) and a latex or solution of the conjugated rubber (B) are mixed, and then a dispersion medium is separated from the resulting mixture. A method for producing the rubber composition according to any one of claims 1 to 16.

17. The production method according to claim 16, wherein latexes or solutions of the conjugated rubber (A) and the conjugated rubber (B) are mixed.