JP2002201307A - Rubber composition and crosslinked material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a rubber composition comprising silica having low heat build-up and improved abrasion resistance without lowering mechanical characteristics and grip performances and a crosslinked material obtained by crosslinking the rubber composition. SOLUTION: This rubber composition comprises (1) 100 pts.wt. of a rubber composed of 1-20 pts.wt. of a diene-based rubber (A) having >=40 mol% vinyl bond amount and 80-99 pst.wt. of a diene-based rubber (B) having <40 mol% vinyl bond amount and a Mooney viscosity 10-150 higher than that of the diene- based rubber (A) and (2) 10-150 pts.wt. of silica in the ratio of the amount of the diene-based rubber (A)/the silica of 0.01-0.3. This crosslinked material is obtained by crosslinking the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a diene rubber composition containing silica and a crosslinked product obtained by crosslinking the same. More specifically, the present invention relates to a diene rubber composition having low heat build-up and heat resistance without deteriorating mechanical properties and grip performance. The present invention relates to a diene rubber composition having improved wear resistance and a crosslinked product obtained by crosslinking the same.

[0002]

2. Description of the Related Art Silica-containing tire treads are excellent in fuel economy, but have poor abrasion resistance and have been continuously improved. With the advent of highly dispersible silica, the wear resistance in normal driving of automobiles has become a practical level,
Severe wear conditions are not sufficient. One of the causes is considered to be that a sufficient reinforcing effect cannot be exhibited due to low affinity of silica for the diene rubber. In order to solve this problem, a rubber composition containing a diene rubber having a high vinyl bond and a high affinity for silica has been proposed.

[0003] For example, Japanese Patent Application Laid-Open No. 8-53002 discloses a high vinyl content styrene-butadiene copolymer.
Rubber containing 70 parts by weight and 90 to 30 parts by weight of a styrene-butadiene copolymer having a high styrene content, 10 to 60 parts by weight of each of two types of carbon black having different nitrogen specific surface areas, and 10 to 40 parts by weight of silica. It has been proposed to use the composition in the tire tread to balance steering stability, abrasion resistance and rolling resistance properties. However, as shown in Comparative Examples 6 and 7 of the above publication, the mixing ratio of silica is There is a problem that abrasion resistance decreases as the number increases.

Further, Japanese Patent Application Laid-Open Nos. 8-333481, 8-333482, and 9-1838
No. 68 proposes to improve abrasion resistance by blending silica in a diene rubber comprising a styrene-butadiene copolymer, a high cis polybutadiene rubber, and a polybutadiene having a high vinyl bond. In the examples of the above publication, 300% modulus and tan at 0 ° C.
δ is low, and there is a problem in mechanical properties and grip properties.

Further, JP-A-8-319376 and JP-A-10-25369 disclose isoprene /
It has been proposed to mix silica and carbon black with a diene rubber composed of a butadiene copolymer rubber, a high cis diene rubber, and a high vinyl polybutadiene rubber. It can not be said.

[0006] As described above, the conventional techniques have problems that the wear resistance is insufficiently improved, and that the mechanical properties and grip properties are deteriorated.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a rubber composition containing silica, which has improved low heat build-up and abrasion resistance without deteriorating mechanical properties and grip performance, and a cross-linked rubber obtained by cross-linking the same. The purpose is to provide things.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, a diene rubber having a relatively low Mooney viscosity and a high vinyl bond and another diene rubber have been specified. It has been found that by mixing silica at a specific ratio with a high vinyl-bonded diene rubber at a specific ratio, it is possible to achieve both a sufficient reinforcing effect and good abrasion resistance. The invention has been completed.

Thus, according to the present invention, (1) 1 to 20 parts by weight of a diene rubber (A) having a vinyl bond content of 40 mol% or more, and having a vinyl bond content of less than 40 mol% and having a Mooney viscosity of diene rubber. 10-15 from Mooney viscosity of (A)
0 100 parts by weight of a rubber comprising 80 to 99 parts by weight of a diene rubber (B) and (2) 10 to 150 parts by weight of silica, wherein the ratio of the amount of diene rubber (A) / the amount of silica is A rubber composition characterized by being 0.01 to 0.3, and a crosslinked product obtained by crosslinking the rubber composition are provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition of the present invention comprises 1 to 20 parts by weight of a diene rubber (A) having a vinyl bond amount of 40 mol% or more and a diene rubber (B) 80 having a vinyl bond amount of less than 40 mol%. Contains up to 99 parts by weight of rubber.

The diene rubber (A) according to the present invention is a homopolymer of a conjugated diene monomer or a copolymer of another monomer copolymerizable with the conjugated diene monomer. The amount of vinyl-bonded units (1,2-vinyl-bonded units and 3,4-vinyl-bonded units) of the conjugated diene monomer contained in the polymer is 40 mol% based on the total amount of all monomer units. As described above, the content is preferably 50 to 80 mol%. The Mooney viscosity of the diene rubber (A) is usually 5 to 150,
Preferably it is 15-100, more preferably 30-80.

The conjugated diene monomer used for the diene rubber (A) includes, for example, 1,3-butadiene,
Methyl-1,3-butadiene, 2,3-dimethyl-1,
3-butadiene, 2-chloro-1,3-butadiene,
1,3-pentadiene and the like can be mentioned. Among these, 1,3-butadiene and 2-methyl-1,3-butadiene are preferred, and 1,3-butadiene is more preferred.
These conjugated diene monomers can be used alone or in combination of two or more.

The monomer copolymerizable with the conjugated diene monomer is not particularly limited. Examples thereof include amino group-containing vinyl monomers, pyridyl group-containing vinyl monomers, hydroxyl group-containing vinyl monomers, alkoxyl group-containing vinyl monomers, and aromatic vinyl monomers. Mers are preferred. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4
-Diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene, monofluorostyrene and the like.
Among these, styrene is particularly preferred. These copolymerizable monomers may be used alone or in combination of two or more.

The method for producing the diene rubber (A) of the present invention is not particularly limited. For example, polymerization may be carried out in a hydrocarbon solvent in the presence of a polar compound using an organic active metal as an initiator. As the hydrocarbon solvent used in this polymerization step,
Examples thereof include aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. As polar compounds, ether compounds,
Tertiary amines, alkali metal alkoxides, phosphine compounds and the like are mentioned, and ethers and tertiary amines are preferred.

As the organic active metal, an organic alkali metal is preferable, and examples thereof include an organic lithium compound such as an organic monolithium compound and a polyfunctional organic lithium compound, an organic sodium compound, and an organic potassium compound, and an organic lithium compound is more preferable. And organic monolithium compounds are particularly preferred.

The amount of the hydrocarbon solvent used is not particularly limited, but is preferably used so that the monomer concentration becomes 1 to 50% by weight. The amount of the organic active metal used is appropriately selected depending on the required molecular weight of the produced polymer.
0.1 to 30 mmol per 100 g is preferred.

The amount of the polar compound used per mole of the organic active metal used as the initiator is preferably 0.1 to 10 mol.
0 mol, more preferably 0.3 to 50 mol, particularly preferably 0.4 to 30 mol. If the amount of the polar compound is too small, the vinyl bond ratio of the conjugated diene bond portion cannot be sufficiently increased, and if it is too large, the vinyl bond ratio does not easily increase.

The polymerization reaction is preferably carried out at -78 to 150 ° C.
Is carried out in a polymerization manner such as a batch system or a continuous system, preferably in a batch system.

The diene rubber (A) is a terminal-modified diene rubber obtained by reacting a polymer chain terminal bonded to an organic active metal with a modifier, or an adduct of an organic alkali metal and an amino group-containing monomer. A terminal-modified diene rubber may be used in which the polymerization start end is modified using an organic alkali metal containing a nitrogen atom such as an organic alkali metal amide as an initiator. In general, the higher the modification rate by terminal modification, the better the wet grip properties and low heat buildup. When the modifier is reacted with the polymer chain, a polar group can be introduced into the polymer chain at the organic active metal binding site.

The modifier is preferably one which can introduce a tin atom, a nitrogen atom, etc. into the polymer chain. As a modifier into which a tin atom can be introduced, trimethylmonochlorotin, triphenylmonochlorotin and the like can be mentioned. Examples of the modifier capable of introducing a nitrogen atom include N, N-disubstituted aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate, acrylic acid or methacrylic acid esters such as N, N-dimethylaminoethyl methacrylate, and N, N-dimethylaminoethyl methacrylate. , N-disubstituted aminoalkyl methacrylate compounds;
N, N-dimethylaminopropylacrylamide, N,
N, N-disubstituted aminoalkyl acrylamide compounds such as N-dimethylaminopropyl methacrylamide or N, N-disubstituted aminoalkyl methacrylamide compounds; N, N-dimethylaminoethylstyrene, N, N
An N, N-disubstituted aminoaromatic vinyl compound such as diethylaminoethylstyrene or a vinyl compound having a pyridyl group; N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone,
N-substituted cyclic amides such as -methyl-ε-caprolactam; N-substituted cyclic ureas such as 1,3-dimethylethylene urea and 1,3-diethyl-2-imidazolidinone;
4,4′-bis (dimethylamino) benzophenone,
N-substituted aminoketones such as 4,4'-bis (diethylamino) benzophenone; N-substituted aminoaldehydes such as 4-N, N-dimethylaminobenzaldehyde; N-substituted carbodiimides such as dicyclohexylcarbodiimide; N-ethylethylidene Imine, N-
Schiff bases such as methylbenzylideneimine; 2,4
-Aromatic isocyanates such as tolylene diisocyanate, and polymers thereof. Among these, N, N-disubstituted aminoalkyl acrylamide compounds, N, N-disubstituted amino aromatic vinyl compounds, N-
Preferred are substituted cyclic amides, N-substituted cyclic ureas, and N-substituted amino ketones, particularly N, N-dimethylaminopropylacrylamide, N, N-diethylaminoethylstyrene, N-phenyl-2-pyrrolidone, 1,3- Diethyl-2-imidazolidinone and 4,4'-bis (diethylamino) benzophenone are preferred.

After modifying the polymer chain with these modifiers, if the terminally modified polymer chain can be polymerized with the monomer, the monomer may be further added and polymerized.

After the terminal modification, a modification treatment may be further performed. For example, when a tertiary amino group is introduced into the polymer chain, the tertiary amino group may be changed to a quaternary amino group by treating with a quaternizing agent. Examples of such quaternizing agents include alkyl nitrate, potassium alkyl sulfate, dialkyl sulfate, alkyl sulfonate, alkyl halide, metal halide and the like.

The reaction temperature and reaction time in the denaturation reaction can be selected from a wide range, but are preferably from 15 to 120.
° C, 1 second to 10 hours. The modification ratio is a ratio of terminal-modified polymer molecules in the whole polymer, and is preferably 1
0 to 100% by weight. The denaturation rate is the ratio of the absorption intensity (UV) measured by an ultraviolet-visible spectrophotometer to the differential refractive index (RI) measured by a differential refractometer of GPC (UV / R
I) can be determined and determined by a calibration curve prepared in advance.

The diene rubber (A) may be a coupling type diene rubber in which polymer chain terminals bonded to an organic active metal are bonded to each other. In order to produce the coupling type diene rubber, in the production of the diene rubber (A), the polymer chain end bonded to the organic active metal is reacted with the coupling agent before the polymerization reaction stopping step. Good.
By reacting the coupling agent with the polymer chain, a plurality of polymer molecule polymer chains are bonded at the organic active bonding site located at the end of the polymer molecule via the coupling agent, and the coupling type diene rubber Becomes

The coupling agent is not particularly limited as long as a coupling type diene rubber can be produced, and a tin coupling agent such as tin tetrachloride, and a silicon coupling agent such as silicon tetrachloride, tetramethoxysilane, and modified silicone. Agent, unsaturated nitrile-based coupling agent, ester-based coupling agent, halide-based coupling agent, phosphorus-based coupling agent, epoxy-based coupling agent such as tetraglycidyl-1,3-bisaminomethylcyclohexane, isocyanate-based cup Ring agents and the like can be mentioned. These coupling agents can be used alone or in combination of two or more.

The amount of the coupling agent to be used can be appropriately selected according to the required weight average molecular weight, the coupling ratio, the reactivity of the coupling agent, and the like. 10 to 10 equivalents are preferred. The coupling reaction is preferably carried out at 0 to 150 ° C. for 0.5 to 2 minutes.
The reaction is performed under the reaction condition of 0 hour. The coupling ratio can be appropriately selected, but is preferably 10 to 100%. The coupling ratio is determined by G before and after the coupling reaction.
The peak measured by a differential refractometer with a PC is determined from the ratio of the area of the peak after the coupling reaction at the same position as the peak before the coupling reaction to the area of the peak having a higher molecular weight than that after the coupling reaction. be able to.

If necessary, a compounding agent may be added to the polymerization reaction solution after the reaction stopping step, or a process oil may be added to form an oil-extended rubber. When the polymer is heated in the solvent removal or drying step in the next step, it is preferable to add an antioxidant such as a phenol-based stabilizer, a phosphorus-based stabilizer, or a sulfur-based stabilizer in this step. The amount of the antioxidant to be added may be determined according to the type and the like.

The diene rubber (B) according to the present invention is a homopolymer of a conjugated diene monomer or a copolymer of another monomer copolymerizable with the conjugated diene monomer. The amount of vinyl-bonded units (1,2-vinyl-bonded units and 3,4-vinyl-bonded units) of the conjugated diene monomer contained in the polymer is 40 mol% based on the total amount of all monomer units. , Preferably less than 30 mol%.

Specifically, natural rubber, synthetic polyisoprene, polybutadiene, alkyl acrylate-butadiene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isoprene-
Examples include butadiene copolymers, acrylonitrile-butadiene copolymers, partially hydrogenated acrylonitrile-butadiene copolymers, isobutylene-isoprene copolymers, ethylene-propylene-diene copolymers, and mixtures thereof. These rubbers may be oil-extended rubbers that have been oil-extended with an extension oil in advance.

Among them, a styrene-butadiene copolymer containing 1 to 60% by weight, preferably 10 to 55% by weight, more preferably 20 to 50% by weight of styrene units produced by emulsion polymerization or solution polymerization is used. 70% by weight
Those containing the above are preferable because they have an excellent balance between abrasion resistance and grip properties.

The Mooney viscosity of the diene rubber (B) (when the diene rubber (B) is an oil-extended rubber, represents the Mooney viscosity before oil extension) is usually 20 to 200, preferably 30 to 170. , More preferably 50 to 150.

The mixing ratio of the diene rubber (A) and the diene rubber (B) is as follows:
1 to 20 parts by weight, preferably 3 to 20 parts by weight of diene rubber (A)
18 parts by weight, 80 to 99 parts by weight of the diene rubber (B),
Preferably it is 82 to 97 parts by weight. If the compounding ratio of the diene rubber (A) is less than 1 part by weight, the effect of improving the low heat build-up and abrasion resistance is insufficient, and even if the compounding ratio of the diene rubber (A) exceeds 20 parts by weight. And wear resistance is reduced.

The Mooney viscosity of the diene rubber (B) is higher than the Mooney viscosity of the diene rubber (A).
It is 0-150, preferably 15-130. If the difference in Mooney viscosity between the diene rubber (B) and the diene rubber (A) is less than 10, the effect of reinforcing the rubber with silica will be insufficient, and if it is greater than 150, the workability will be poor.

The rubber component of the present invention includes acrylic rubber, epichlorohydrin rubber, fluorine rubber, silicone rubber, ethylene-propylene rubber, urethane rubber and the like having no conjugated diene unit as long as the effects of the present invention are not impaired. May be included.

The rubber composition of the present invention is used in an amount of 10 to 150 parts by weight, preferably 20 to 120 parts by weight, per 100 parts by weight of the rubber component.
It contains parts by weight, more preferably 40 to 100 parts by weight of silica. The ratio of the amount of the diene rubber (A) / the amount of the silica is 0.01 to 0.3, preferably 0.02 to 0.2.
7, more preferably 0.04 to 0.24. By setting the ratio of the amount of the diene rubber (A) to the amount of the silica in this range, both abrasion resistance and low heat generation can be achieved.

Examples of the silica include, but are not particularly limited to, 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 hydrated silicic acid as a main component is preferable. In addition, carbon-silica dual phase with silica supported on carbon black surface
A filler may be used, which is preferable because it has excellent wear resistance and low heat generation. These silicas can be used alone or in combination of two or more.

The specific surface area of the silica according to the nitrogen adsorption specific surface area (BET method) is preferably 50 to 400 m ² / g, more preferably 100 to 220 m ² / g, and particularly preferably 120 to 190 m ² / g. Within this range, excellent mechanical properties, abrasion resistance, low heat generation, and the like are obtained. The nitrogen adsorption specific surface area is a value measured by the BET method according to ASTM D3037-81.

The pH of the silica is preferably acidic, that is, less than pH 7, and more preferably pH 5 to 6.9.

When a silane coupling agent is added to the rubber composition of the present invention, low heat buildup and abrasion resistance are further improved. Although the silane coupling agent is not particularly limited, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-
(Β-aminoethyl) -γ-aminopropyltrimethoxysilane, bis (3- (triethoxysilyl) propyl) tetrasulfide, bis (3- (triethoxysilyl) propyl) disulfide and the like, and JP-A-6-248
No. 116, tetrasulfides such as γ-trimethoxysilylpropyldimethylthiocarbamyltetrasulfide and γ-trimethoxysilylpropylbenzothiazyltetrasulfide. From the viewpoint of avoiding scorch at the time of kneading, 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 blending amount of the silane coupling agent with respect to 100 parts by weight of silica is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, particularly preferably 2 to 15 parts by weight.
Parts by weight.

The rubber composition of the present invention may contain carbon black such as furnace black, acetylene black, thermal black, channel black and graphite. Among these, furnace black is preferred, and specific examples thereof include SAF, ISAF,
ISAF-HS, ISAF-LS, IISAF-HS,
HAF, HAF-HS, HAF-LS, FEF and the like.

These carbon blacks can be used alone or in combination of two or more. The blending amount of carbon black with respect to 100 parts by weight of the rubber component is usually 150 parts by weight or less, and preferably 10 to 150 parts by weight in total of carbon black and silica.

The nitrogen adsorption specific surface area of carbon black (N
2SA) is not particularly limited, but is preferably from 5 to 20.
0 m ² / g, more preferably 50 to 150 m ² / g, particularly preferably 80~130m ² / g. When the nitrogen adsorption specific surface area is in this range, mechanical properties and abrasion resistance are excellent.

The adsorption amount of dibutyl phthalate (DBP) of carbon black is preferably 5 to 300 ml /
100 g, more preferably 50-200 ml / 100
g, particularly preferably 80 to 160 ml / 100 g. When the DBP adsorption amount is in this range, the mechanical properties and abrasion resistance are excellent, which is preferable.

Further, as carbon black, the adsorption specific surface area of cetyltrimethylammonium bromide (CTAB) disclosed in JP-A-5-230290 is 110 to 170 m ² / g, and 24,000 ps.
DBP (24
M4DBP) When a high-structure carbon black having an oil absorption of 110 to 130 ml / 100 g is used,
The wear resistance is improved.

The rubber composition of the present invention may contain, in addition to the above components, a crosslinking agent, a crosslinking accelerator, a crosslinking activator, an antioxidant, an activator, a process oil, a plasticizer, a lubricant, a filler according to a conventional method. And the like can be contained in necessary amounts.

Examples of the crosslinking 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 peroxide and ditertiary butyl par. Organic peroxides such as oxides; quinone dioximes such as p-quinone dioxime and p, p'-dibenzoylquinone dioxime; triethylenetetramine, hexamethylenediaminecarbamate, 4,4'-methylenebis-o-chloroaniline And the like; an organic polyvalent amine compound; an alkylphenol resin having a methylol group; and the like. Of these, sulfur is preferred, and powdered sulfur is particularly preferred. These crosslinking agents are used alone or in combination of two or more.

The amount of the crosslinking agent to be added to 100 parts by weight of the total rubber component is preferably 0.1 to 15 parts by weight, more preferably 0.3 to 10 parts by weight, particularly preferably 0.5 to 5 parts by weight. When the amount of the cross-linking agent is within this range, the composition is excellent in low heat build-up, mechanical properties and abrasion resistance.

Examples of the crosslinking accelerator include N-cyclohexyl-2-benzothiazylsulfenamide, Nt-butyl-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide,
Sulfenamide-based cross-linking accelerators such as N-oxyethylene-2-benzothiazolesulfenamide and N, N'-diisopropyl-2-benzothiazolesulfenamide; diphenylguanidine, dioltotolylguanidine, ortho-tolylbiguanidine and the like Thiourea-based crosslinking accelerators such as diethylthiourea; thiazole-based crosslinking accelerators such as 2-mercaptobenzothiazole, dibenzothiazyldisulfide, and 2-mercaptobenzothiazole zinc salt; tetramethylthiuram monosulfide, tetra Thiuram-based crosslinking accelerators such as methylthiuram disulfide; dithiocarbamic acid-based crosslinking accelerators such as sodium dimethyldithiocarbamate and zinc diethyldithiocarbamate; sodium isopropylxanthate And xanthic acid-based crosslinking accelerators such as zinc, isopropylxanthogenate and zinc butylxanthogenate.

These crosslinking accelerators may be used alone,
Alternatively, two or more of them are used in combination, and those containing a sulfenamide-based crosslinking accelerator are particularly preferred. The compounding amount of the crosslinking accelerator is preferably 0.1 to 15 parts by weight, more preferably 0.3 to 15 parts by weight, based on 100 parts by weight of all rubber components.
10 parts by weight, particularly preferably 0.5 to 5 parts by weight.

The crosslinking activator is not particularly limited, but higher fatty acids such as stearic acid and zinc oxide can be used. As zinc oxide, those having a high surface activity and a particle size of 5 μm or less are preferably used, and active zinc white having a particle size of 0.05 to 0.2 μm and zinc white having a particle size of 0.3 to 1 μm can be exemplified. Also, zinc oxide
A surface-treated material with an amine-based dispersant or wetting agent can be used.

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 amount of the higher fatty acid added to 100 parts by weight of the total rubber component is preferably 0.05 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, and particularly preferably 0.1 to 10 parts by weight.
5 to 5 parts by weight. The amount of zinc oxide added to 100 parts by weight of the total rubber component is preferably 0.05 to 10 parts by weight,
More preferably 0.1 to 5 parts by weight, particularly preferably 0.1 to 5 parts by weight.
5 to 3 parts by weight. When the amount of the crosslinking activator is in this range, the unvulcanized rubber composition is excellent in processability, mechanical properties, abrasion resistance and the like.

Other compounding agents include activators such as diethylene glycol, polyethylene glycol and silicone oil; fillers such as calcium carbonate, talc and clay; waxes.

The rubber composition of the present invention can be obtained by kneading the components according to a conventional method. For example, a rubber composition can be obtained by kneading a compounding agent excluding a crosslinking agent and a crosslinking accelerator and a rubber component, and then mixing the kneaded product with a crosslinking agent and a crosslinking accelerator. The kneading temperature of the compounding agent and the rubber component excluding the crosslinking agent and the crosslinking accelerator is preferably 80 to 200C, more preferably 100 to 190C, and particularly preferably 120 to 190C.
180 ° C. The kneading time of the compounding agent excluding the crosslinking agent and the crosslinking accelerator and the rubber component is preferably 30 seconds to 30 minutes. Mixing of a crosslinking agent and a crosslinking accelerator is usually 100 ° C. or less,
Preferably, it is performed after cooling to 80 ° C. or less.

The rubber composition of the present invention is usually used as a rubber crosslinked product. The crosslinking method is not particularly limited, and may be selected according to the shape and size of the crosslinked product. The mold may be filled with the crosslinkable rubber composition and heated to perform crosslinking at the same time as molding. Alternatively, a previously molded uncrosslinked rubber composition may be heated to perform crosslinking. The crosslinking temperature is preferably from 120 to 200C, more preferably from 140 to 18C.
0 ° C., and the crosslinking time is usually about 1 to 120 minutes.

[0056]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples. Parts and percentages in the following are by weight unless otherwise specified. In addition, the measurement of various physical properties was performed according to the following method.

(1) The amount of bound styrene in the polymer is determined by JI
It was measured according to SK 6383 (refractive index method). (2) The content of the vinyl bonding unit in the polymer was determined by ¹ H NMR.
Was measured. (3) Mooney viscosity: Mooney viscosity of rubber component (ML
_{1 + 4} , 100 ° C.) was measured according to JIS K6300. (4) Mechanical properties of cross-linked rubber: For the tensile strength of the cross-linked rubber, the tensile strength, elongation and 300% stress were measured according to JIS K6301. The larger the value, the better. (5) Grip property: RDA-I manufactured by Rheometrics
Using I, tan δ at 0 ° C. was measured under the conditions of 0.5% twist and 20 Hz. When this tan δ (0 ° C.) value is large, it indicates that the grip property is excellent. (6) Exothermicity: Using RDA-II manufactured by Rheometrics, tan δ at 60 ° C. was measured under the conditions of 0.5% twist and 20 Hz. When this tan δ (60 ° C.) value is small, it indicates that the heat generation is excellent. (7) Abrasion resistance index: A pico abrasion test was performed according to JIS K 6264. The higher the wear resistance index, the better the wear resistance.

Production Example VBR1 Cyclohexane 3200 was placed in an autoclave equipped with a stirrer.
g, 500 g of 1,3-butadiene and 10 mmol of tetramethylethylenediamine were charged and heated to 40 ° C., and 7.3 mmol of n-butyllithium was added to initiate polymerization. 10 minutes after the start of polymerization, over 40 minutes,
500 g of 3-butadiene were continuously added at a constant rate. After confirming that the polymerization conversion rate reached 100%, 0.67 mmol of tin tetrachloride was added and reacted for 10 minutes. Next, 3.5 mmol of 1,3-diethyl-2-imidazolidinone (DEI) was added and reacted for 15 minutes, and then methanol was added to terminate the polymerization. The highest temperature reached during the polymerization was 60 ° C.

Next, a rubber component 1 was added to the polymerization reaction solution after the polymerization was stopped.
2,4-bis (n-octylthiomethyl) per 00 parts
0.12 parts of -6-methylphenol was added, the polymer was recovered by a steam stripping method, dewatered by a roll, and further dried by a hot air dryer to obtain VBR1.

VBR2: 4.0 mmol of tetramethylethylenediamine, n-
Butyl lithium was changed to 8.1 mmol, tin tetrachloride was tetraglycidyl-1,3-bisaminomethylcyclohexane 1.6 mmol (TGBAC), and 1,3-diethyl-2-imidazolidinone was 4-diethylaminoethyl. Except for making styrene (DEAESt) 1.2 mmol,
Polymerization and recovery were performed in the same manner as VBR1 to obtain VBR2.

VBR3 tetramethylethylenediamine (7.0 mmol, n-
V except for changing the butyllithium to 10.6 mmol
It polymerized similarly to BR1. After confirming that the polymerization conversion reached 100%, 0.94 mmol of tin tetrachloride was added and reacted for 10 minutes, and 0.94 mmol of tetramethoxysilane was added and reacted for 10 minutes. Next, 3.0 mmol of N-phenyl-2-pyrrolidone (NPP) was added and reacted for 15 minutes. The polymer was recovered from the addition of the terminator in the same manner as in the case of VBR1 to obtain VBR3.

VBR4 9.0 mmol of tetramethylethylenediamine, n-
Butyllithium was changed to 4.7 mmol, tin tetrachloride was changed to 0.75 mmol of tetramethoxysilane, and 1,3-diethyl-2-imidazolidinone was changed to 1.9 mmol of 4-diethylaminoethylstyrene. Polymerization was carried out in the same manner. Further, a process oil (Fucor M, manufactured by Fujikosan Co., Ltd.) was added to 100 parts of rubber so as to become 37.5 parts, and then the polymer was recovered in the same manner as VBR1.
BR4 was obtained.

VSBR1 Cyclohexane 3200 was added to an autoclave equipped with a stirrer.
g, 425 g of 1,3-butadiene, 75 g of styrene and 13 mmol of tetramethylethylenediamine were charged, and the mixture was heated to 40 ° C., and 7.3 mmol of n-butyllithium was added to initiate polymerization. 5 minutes after 10 minutes from the start of polymerization
Over a period of 0 minutes, 410 g of 1,3-butadiene and 90 g of styrene were continuously added at a constant rate. Polymerization conversion rate is 1
After confirming that the content of the mixture had reached 00%, 4 g of 1,3-butadiene was added and reacted for 5 minutes.
Mmol was added and reacted for 10 minutes. Then, dimethylaminopropylacrylamide (DMAPAA)
After adding 5.0 mmol and reacting for 15 minutes, methanol was added to terminate the polymerization. The highest temperature reached during the polymerization was 60 ° C. The polymer was recovered in the same manner as VBR1 to obtain VSBR1.

VSBR2 Cyclohexane 3200 was added to an autoclave equipped with a stirrer.
g, 360 g of 1,3-butadiene, 140 g of styrene, and 5.3 mmol of tetramethylethylenediamine were charged, and after the temperature was raised to 40 ° C., 9.2 mmol of n-butyllithium was added to initiate polymerization. From 10 minutes after the initiation of the polymerization, over a period of 50 minutes, 410 g of 1,3-butadiene and 90 g of styrene were continuously added at a constant rate. After confirming that the polymerization conversion rate reached 100%, 4 g of 1,3-butadiene was added and reacted for 5 minutes, and then tetraglycidyl-1,3-bisaminomethylcyclohexane (TG
BAC) was added and reacted for 15 minutes. Next, 2.6 mmol of 4,4'-bis (diethylamino) benzophenone (EAB) was added and reacted for 15 minutes, and then methanol was added to terminate the polymerization. The highest temperature reached during the polymerization was 60 ° C. The recovery of the polymer
VSBR2 was obtained in the same manner as VBR1.

VBR1-4 and VSBR1,2 were used as the diene rubber (A) component. Table 1 shows the structure and physical properties.

[0066]

[Table 1]

S-SBR1 Cyclohexane 4000 was added to an autoclave equipped with a stirrer.
g, 320 g of styrene, 280 g of 1,3-butadiene and 2.0 mmol of tetramethylethylenediamine, and 9.3 mmol of n-butyllithium were added.
Polymerization was started at 50 ° C. Twenty minutes after the start of the polymerization, a mixture of 30 g of styrene and 370 g of 1,3-butadiene was continuously added. After confirming that the polymerization conversion reached 100%, 1.3 mmol of tin tetrachloride was added, and 30
Allowed to react for minutes. The highest temperature reached during the polymerization was 75 ° C. After completion of the reaction, methanol was added to terminate the polymerization. The recovery of the polymer was performed in the same manner as in the case of VBR1, and S-SBR was recovered.
1 was obtained.

S-SBR2 Cyclohexane 4000 was added to an autoclave equipped with a stirrer.
g, 270 g of styrene, 330 g of 1,3-butadiene and 2.5 mmol of tetramethylethylenediamine, and 6.8 mmol of n-butyllithium were added.
Polymerization was started at 45 ° C. Twenty minutes after the start of the polymerization, a mixture of 80 g of styrene and 320 g of 1,3-butadiene was continuously added. After confirming that the polymerization conversion rate reached 100%, 1.0 mmol of tetramethoxysilane was added and reacted for 30 minutes. The highest temperature reached during the polymerization was 65 ° C. After completion of the reaction, methanol was added to stop the polymerization, and 100 parts of rubber in the polymerization reaction solution was added with 37.5 parts of process oil (Fucor M). Collect the coalesced, S-SB
R2 was obtained.

As the other rubbers in the examples, the following rubbers were used. E-SBR1: Nipol Zeon Corporation, Nipol 1721 E-SBR2: Nippon Zeon Corporation, Nipol 1712 E-SBR3: Nippon Zeon Corporation, Nipol 1502 E-SBR4: Nippon Zeon Corporation, Nipol 9520

S-SBR1,2 and E-SBR1-4
Was used as a diene rubber (B) component. Table 2 shows the structure and physical properties.

[0071]

[Table 2]

Examples 1 to 4 and Comparative Examples 1 and 2 In a Brabender type mixer having a capacity of 250 ml, the raw rubber and the process oil (Fucor M,
Fujikosan) and silica (Zeosil)
1165MP, 53 parts of Rhodia) and 6.4 parts of silane coupling agent (Si69, Degussa) 110
After mixing for 2 minutes at a starting temperature of 27 ° C., 27 parts of silica, zinc oxide (Zinc flower # 1, manufactured by Honjo Chemical Co., particle size 0.4 μm)
m) 2 parts, stearic acid 2 parts, and an antioxidant (Nocrack 6C (6PPD), manufactured by Ouchi Shinko Co., Ltd.) were added and kneaded for 2 minutes. The resulting mixture was mixed with 1.4 parts of sulfur and a crosslinking accelerator (N-cyclohexyl-2-
A mixture of 1.7 parts of benzothiazylsulfenamide (CBS) and 1.8 parts of diphenylguanidine (DPG)) was added to an open roll at 50 ° C. and kneaded to obtain a rubber composition. The obtained rubber composition was press-crosslinked at 160 ° C. for 30 minutes to prepare a test piece, and each physical property was measured. The measured value was represented by an index with Comparative Example 1 being 100. Table 3 shows the results.

[0073]

[Table 3]

Example 5, Comparative Examples 3 and 4 Ultrasil 7000GR (manufactured by Degussa) 55 parts as silica was used, and Si69 was changed to 4.4 parts, stearic acid was changed to 1 part, and DPG was changed to 1.1 parts. A test piece was prepared and the physical properties were measured in the same manner as in Example 1 (the addition of silica was divided into two times in the same manner as in Example 1;
7 parts, a second time 18 parts were added). The measured value is Comparative Example 3
Is represented by an index with 100 as an index. Table 4 shows the results.

[0075]

[Table 4]

As is clear from Tables 3 and 4, the rubber compositions of Examples 1 to 5 of the present invention have improved low heat build-up and abrasion resistance without deteriorating mechanical properties and grip performance. You can see that there is. In contrast, Comparative Example 1
Nos. 4 to 4 are inferior in abrasion resistance because the rubber composition deviates from the conditions of the present invention.

Example 6, Comparative Examples 5 and 6 In a Brabender type mixer having a capacity of 250 ml, raw rubber and process oil (Fucor M) having the composition shown in Table 5 were used.
And silica (Zeosil 1135MP,
40 parts of Rhodia Co., Ltd.) and 2.7 parts of a silane coupling agent (Si69) were mixed for 2 minutes at a starting temperature of 110 ° C., and then carbon black N339 (Siest KH,
40 parts, manufactured by Tokai Carbon Co., Ltd., zinc oxide (zinc flower # 1) 2
Parts, stearic acid 2 parts and antioxidant (6PPD) 2
And kneaded for another 2 minutes. The obtained mixture, 1.4 parts of sulfur and a crosslinking accelerator (a mixture of 1.7 parts of CBS and 0.9 part of DPG) were added to an open roll at 50 ° C and kneaded to obtain a rubber composition. The obtained rubber composition was press-crosslinked at 160 ° C. for 30 minutes to prepare a test piece, and each physical property was measured. The measured value was represented by an index with Comparative Example 5 being 100. Table 5 shows the results.

[0078]

[Table 5]

As shown in Table 5, even when carbon black is used in combination with the reinforcing agent, the rubber composition of Example 6 of the present invention has improved low heat build-up and abrasion resistance. On the other hand, in Comparative Examples 5 and 6, the mixing ratio of silica and VBR2 was outside the conditions of the present invention, and the wear resistance was insufficient.

Example 7 and Comparative Examples 7 and 8 Test pieces were prepared in the same manner as in Example 1 except that Nipsil AQ (manufactured by Nippon Silica Co., Ltd.) was used as silica and that Si69 was changed to 8 parts, and physical properties were measured. It was measured. The measured value was represented by an index with Comparative Example 7 being 100. Table 6 shows the results.

[0081]

[Table 6]

As shown in Table 6, the rubber composition of Example 7 has improved low heat build-up and abrasion resistance, whereas Comparative Example 8 has a diene rubber (A) component and a diene rubber ( B)
The difference in Mooney viscosity of the components is outside the conditions of the present invention,
Abrasion resistance has deteriorated.

[0083]

The rubber composition of the present invention has improved low heat build-up and abrasion resistance without deteriorating mechanical properties and gripping performance, and thus can be used in various applications such as treads and carcass. , Sidewalls, bead parts, etc., or for rubber products such as hoses, window frames, belts, shoe soles, anti-vibration rubber, automobile parts, impact-resistant polystyrene, ABS resin, etc. It can be used as a resin-reinforced rubber. In particular,
The rubber composition of the present invention makes use of the above properties and is particularly excellent in tire tread of fuel-efficient tires, but also in all season tires, high performance tires, tire treads such as studless tires, sidewalls, under treads, carcass, It can be used for beats and the like.

Claims (4)

[Claims] (1) 1 to 20 parts by weight of a diene rubber (A) having a vinyl bond amount of 40 mol% or more, and a vinyl bond amount of 40
Less than mol%, the Mooney viscosity of which is diene rubber (A)
100 parts by weight of a rubber consisting of 80 to 99 parts by weight of a diene rubber (B) 10 to 150 higher than the Mooney viscosity of (a) and (2) 10 to 150 parts by weight of silica, and the amount of the diene rubber (A) / The ratio of the amount of silica is 0.01 to 0.1.
3. A rubber composition, which is 3. 2. The diene rubber (B) has a styrene unit of 1
The rubber composition according to claim 1, wherein the rubber composition contains at least 70% by weight of a styrene-butadiene copolymer containing from 60 to 60% by weight. 3. A crosslinked product obtained by crosslinking the rubber composition according to claim 1 or 2. 4. The crosslinked product according to claim 3, which is used for a tire tread.