The Yokohama Rubber Co., Ltd.

The Yokohama Co., Ltd.

Yoshihiro Kameda

Makoto Ashiura

Takashi Shirokawa

Ayumi Naka

Masaki Satou

Naoya Amino

Keisuke Maejima

Masaki Sato

Satoshi Mihara

Kazuto Yamakawa

Kazuya Uenishi

Yu Shinke

Misaki Matsumura

Tsuyoshi Okamoto

Yoichi Takizawa

Ayaki Kazariya

Miyuki Oka

Yasuhiro Yamada

Akitomo Sato

Satoru Yamakawa

Hideaki Sawa

Satoru c/o Sanyo Chem Ind Ltd Yamakawa

An object of the present invention is to provide a method of producing a copolymer that produces an aromatic vinyl-diene copolymer having a low glass transition temperature, and a method of producing a rubber composition using the method. The subject method produces an aromatic vinyl-diene copolymer having a content of repeating units derived from an aromatic vinyl in an amount of 18 mass % or greater, and among repeating units derived from a diene, a proportion of a vinyl structure of 8 mol % or less, a proportion of a 1,4-trans structure of 60 mol % or less, and a proportion of a 1,4-cis structure from 40 to 95 mol %, the method including copolymerizing a monomer containing an aromatic vinyl and a diene using an initiator prepared with an organolithium compound, an alkylaluminum, a metal alcoholate, and at least one polar compound selected from the group consisting of water and an alcohol.

Production method for aromatic vinyl-diene copolymer and production method for rubber composition

A pneumatic tire using as a tread part, a rubber composition containing a high silica-content rubber composition having a difference F-S between an amount of filler F and an amount of a softening agent S of 60 to 90 parts by weight and having a durometer hardness measured at 20&#xb0; C. of 65 to 76.

Pneumatic tire

A rubber composition comprises a diene rubber including not less than 30% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 1 to 25 parts by weight of a tackifying resin, and from 25 to 80 parts by weight of a filler comprising not less than 50% by weight of silica. The modified conjugated diene polymer rubber has a terminal modified group comprising a functional group that interacts with silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, weight-average molecular weight is from 600,000 to 1,000,000, and glass transition temperature is from &#x2212;22 to &#x2212;32&#xb0; C. A glass transition temperature of the tackifying resin is from 50 to 110&#xb0; C. higher than the glass transition temperature of the modified conjugated diene polymer rubber.

Rubber composition for use in tire treads

A rubber composition for use in tire treads comprises a diene rubber including not less than 40% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 66 to 110 parts by weight of a filler. The filler comprises not less than 50% by weight of silica. The modified conjugated diene polymer rubber is obtained by copolymerizing a conjugated diene monomer unit and an aromatic vinyl monomer unit in a hydrocarbon solvent using an organic active metal compound as an initiator. A resulting active conjugated diene polymer chain thereof has a terminal modified group, obtained by reacting at least one type of compound having a functional group that is reactable with the active terminal of the polymer chain. Moreover, the terminal modified group has a functional group that interacts with the silica.

The present technology provides a rubber composition comprising from 30 to 100 parts by weight of a carbon black, and from 10 to 80 parts by weight of an inorganic filler per 100 parts by weight of a diene rubber, wherein the inorganic filler has from 20 to 80% particles of a particle size of at most 5 &#x3bc;m; and when an aluminum content in the inorganic filler is defined as Wal wt. % and a silicon content is defined as Wsi wt. %, the aluminum content Wal is from 11 to 40 wt. %, and a ratio Wal/(Wal+Wsi)&#xd7;100 of aluminum to a total of aluminum and silicon is from 15 to 38 wt. %.

Rubber composition for tire

A rubber composition for tire tread contains a diene-based rubber including 30 wt % or more of a terminal modifying group-containing conjugated diene-based copolymer, silica, carbon black, and at least one of silane coupling agents represented by specified formulae. The total amount of silica and carbon black in the composition is 35 to 140 parts by weight relative to 100 parts by weight of the diene-based rubber, while the silane coupling agent content is 4 to 18 wt % on the silica content. The copolymer is produced by a specified method such that the aromatic vinyl monomer content in the copolymer is 38 to 48 wt %, the vinyl unit content in all the conjugated diene-based monomers is 20 to 35 mol %, the weight average molecular weight of the copolymer is 600,000 to 1,000,000, and the terminal modifying group in the copolymer contains a functional group which interacts with the silica.

Rubber composition for tire tread and pneumatic tire using the same

A rubber composition for a run-flat tire comprises from 20 to 100 parts by weight of a reinforcing filler per 100 parts by weight of a diene rubber containing from 10 to 80 wt. % of butadiene rubber and from 10 to 40 wt. % of natural rubber; wherein the reinforcing filler contains at least 50 wt. % of carbon black; a mode diameter Dst in a mass distribution curve of a Stokes diameter of aggregates of the carbon black is at least 145 nm; a nitrogen adsorption specific surface area NSA is from 45 to 70 m/g; and a ratio NSA/IA of the nitrogen adsorption specific surface area NSA to an iodine adsorption IA (units: mg/g) is from 1.00 to 1.40.

Rubber composition for run-flat tire

A rubber composition comprises a diene rubber including not less than 25% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 25 to 65 parts by weight of a filler, the filler comprising not less than 50% by weight of silica. The silica has a DBP absorption number of 190 to 250 ml/100 g, an NSA of 194 to 225 m/g, and a CTAB of 185 to 215 m/g. A ratio of the NSA to the CTAB is from 0.9 to 1.4. The modified conjugated diene polymer rubber has a terminal modified group including a functional group that interacts with the silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, and weight-average molecular weight is from 600,000 to 1,000,000.

Rubber composition for tire tread

A pneumatic tire with superior durability having a tread part comprising a cap tread layer (layer A) and an under tread layer (layer B), wherein, in the pneumatic tire, when storage elastic moduli of the rubber compositions constituting the layer A and the layer B are designated as Eand E, the storage elastic moduli E(60&#xb0; C.) and E(60&#xb0; C.) determined at a temperature of 60&#xb0; C. satisfy the following formulae (1) and (2):(60&#xb0; C.)/(60&#xb0; C.)&#x2266;0.66&#x2003;&#x2003;(1)10(MPa)&#x2266;(60&#xb0; C.)&#x2003;&#x2003;(2)

Pneumatic tire with high speed durability

A rubber composition for a tire containing 100 parts by weight of a rubber, 1 to 30 parts by weight of a polyether (E1) having the formula (I):R&#x2014;{(OCHCHCHCH)(OA)&#x2014;OH}&#x2003;&#x2003;(I)wherein Ris a residue of a Cto Ccompound having 1-6 hydroxyl groups, from which at least one hydroxyl group is removed, A Ls a Cto Calkylene group other than a 1,4-butylene group, q is an integer of 1 to 6, and m and n are independently integers of 1 to 600, and/or the derivative thereof (E2) and 10 to 180 parts by weight of a filler, which is excellent in processability, silica dispersability abrasion resistance and wet braking performance, etc.

Rubber composition for tire and pneumatic tire made therefrom

Disclosed is a sulfur-containing conjugated diolefin copolymer rubber composed of a conjugated diolefin and an aromatic vinyl compound, wherein (1) the content of sulfur bound to the rubber is 0.01 mmol % or more, (2) the content of the aromatic vinyl compound polymerization unit is not less than 5 wt % and less than 45 wt % relative to the amount of the copolymer rubber, and (3) the content of a vinyl bond (a 1,2-bond) in the conjugated diolefin polymerization unit is 30 mol % or more relative to the amount of the conjugated diolefin polymerization unit. In the copolymerization between the conjugated diolefin and the aromatic vinyl compound, a sulfur-containing polymerization terminator is used to terminate the reaction of the copolymerization.

Sulfur-containing conjugated diolefin copolymer rubber, and rubber composition comprising the same

Provided is a tire rubber composition blended with an antioxidant that is derived from a raw material other than petroleum resources, the tire rubber composition being capable of achieving an oxidation resistance equal to or higher than a conventional level and of improving forming processability and a low hysteresis loss property. The tire rubber composition includes a blend of: 100 parts by weight of a diene rubber; 5 to 130 parts by weight of an inorganic filler; and 0.01 to 10 parts by weight of a tea extract containing a catechin.

Tire rubber composition

A sulfur-vulcanizable rubber composition containing 100 parts by weight of a diene-based rubber, 1 to 30 parts by weight of an ester-based plasticizer having a saturated cyclic structure of the formula (I): wherein Rand Rindependently indicate a hydrogen atom or a Cto Corganic group and 40 to 120 parts by weight of a reinforcing filler and a pneumatic tire using the same.

Rubber composition

A rubber composition containing 100 parts by weight of a diene-based rubber, 20 to 120 parts by weight of silica, 3 to 15% by weight, based upon the weight of silica, of a sulfur-containing silane coupling agent and (A) 1,5-diazabicyclo[4,3,0]nonene-5 (DBN) having the formula (I): and/or a salt thereof or (B) 0.1 to 3.0 parts by weight of a compound having a piperidine skeleton having the formula (II) or a salt thereof and/or formula (III): wherein n indicates 3 or 5, Rindicates CH or N and Rindicates H or OH when Ris CH, or H when Ris N, and a melamine derivative of formula (IV): wherein Ris a methoxymethyl group (&#x2014;CHOCH) or methylol group (&#x2014;CHOH), the number of methoxymethyl groups is 3 to 6, and the number of methylol groups is 0 to 3, and/or polymer or copolymer resins of the same and a pneumatic tire using the same.

Rubber composition and pneumatic tire using the same

A rubber composition, superior in the processability and rubber properties compared with a rubber composition using a conventional mercaptosilane coupling agent, containing 100 parts by weight of a diene-based rubber, 10 to 160 parts by weight of a reinforcing filler containing silica and 0.1 to 20% by weight, based upon the weight of silica, of a mercaptosilane coupling agent blocked with a compound having a vinyl ether group and a pneumatic tire using the same.

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Hiratsuka, Japan

Yoshihiro Kameda