The Yokohama Rubber Co., Ltd.

Kyoto Institute of Technology

Yu Shinke

Kazuya Uenishi

Makoto Ashiura

Satoshi Mihara

Naoya Amino

Deqing Zou

Motoji Fujita

Ayaki Kazariya

Jun Miyaji

Masaki Sato

Fumito Yatsuyanagi

Yuko Sekine

Yoshihiro Kameda

Ryosuke Sakai

Wataru Sakai

Hideaki Sawa

Takuma Arikawa

Kaori Kurosaka

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 polymer includes a repeating unit represented by Formula (1) and/or a repeating unit represented by Formula (2), and a repeating unit represented by Formula (3) and/or a repeating unit represented by Formula (4), where a proportion of a total of the repeating unit represented by Formula (1) and the repeating unit represented by Formula (2) is greater than 0 mol % but ≤100 mol %; a proportion of a total of the repeating unit represented by Formula (3) and the repeating unit represented by Formula (4) is ≥0 mol % but less than 100 mol %; a proportion of a total of the repeating unit represented by Formula (1) and the repeating unit represented by Formula (3) is ≥20 mol %; and a proportion of a total of the repeating unit represented by Formula (2) and the repeating unit represented by Formula (4) is ≤80 mol %.

Polymer, method of producing polymer, and rubber composition

A rubber composition for a tire contains a diene rubber, silica, and a specific modified butadiene polymer, wherein the diene rubber contains an aromatic vinyl-conjugated diene rubber A and at least one rubber component B selected from an aromatic vinyl-conjugated diene rubber b1 other than the rubber A and a butadiene rubber b2 having a weight average molecular weight of &#x2265;15000. A content of the aromatic vinyl-conjugated diene rubber A is from 30 to 90% by mass, and a content of the rubber component B is from 10 to 70% by mass, an average TG of the diene rubber is lower than &#x2212;20&#xb0; C., a content of the silica is from 80 to 200 parts by mass per 100 parts by mass of the diene rubber, and a content of the modified butadiene polymer is from 1.0 to 25.0% by mass with respect to content of the silica.

Rubber composition for tire, and pneumatic tire

An object of the present invention is to provide a conveyor belt rubber composition having excellent wear resistance and gouging resistance, a method for producing the conveyor belt rubber composition, a conveyor belt formed using the conveyor belt rubber composition, and a belt conveyor equipped with the conveyor belt. The present invention relates to a conveyor belt rubber composition containing a diene rubber containing less than 50 mass % of an aromatic vinyl-conjugated diene copolymer, wherein the aromatic vinyl-conjugated diene copolymer has a content of repeating units derived from an aromatic vinyl of 20 mass % or less, and a proportion of a vinyl structure in repeating units derived from a conjugated diene of 8 mol % or less.

Conveyor belt rubber composition, method for producing conveyor belt rubber composition, conveyor belt, and belt conveyor

The present invention provides a compounding agent which, when used in a rubber composition containing a reinforcing filler, exhibits excellent dispersibility, workability, toughness, low heat build-up, and wear resistance; and a rubber composition containing the compounding agent. A modified butadiene polymer of the present invention has a functional group containing a nitrogen atom and silicon atom at a terminal, a weight average molecular weight of the modified butadiene polymer being from 1000 to 15000, and a molecular weight distribution of the modified butadiene polymer being 2.0 or less.

Modified butadiene polymer and rubber composition

An object of the present invention is to provide a conveyor belt rubber composition having excellent cut resistance and wear resistance, a method for producing the conveyor belt rubber composition, a conveyor belt formed using the conveyor belt rubber composition, and a belt conveyor equipped with the conveyor belt. The present invention relates to a conveyor belt rubber composition containing a diene rubber containing 50 mass % or more of an aromatic vinyl-conjugated diene copolymer, wherein the aromatic vinyl-conjugated diene copolymer has a content of repeating units derived from an aromatic vinyl of more than 20 mass %, and a proportion of a vinyl structure in repeating units derived from a conjugated diene of 8 mol % or less.

A rubber composition of the present technology is a rubber composition including a diene rubber and a filler; the diene rubber containing at least a styrene-butadiene copolymer; a radical generation index of the styrene-butadiene copolymer being not greater than 1.0 and being smaller than a value Y calculated by Equation (1): Y=&#x2212;0.0186&#xd7;(SV mass %+vinyl unit mol %)+1.5.

Rubber composition and pneumatic tire

The present invention is to provide an aromatic vinyl-diene copolymer which exhibits excellent mechanical properties and wear resistance when being formed into a tire, a method for producing the aromatic vinyl-diene copolymer, and a rubber composition containing the aromatic vinyl-diene copolymer. The aromatic vinyl-diene copolymer of an embodiment of the present invention is an aromatic vinyl-diene copolymer which is a copolymer of an aromatic vinyl and a diene, wherein the content of a repeating unit derived from an aromatic vinyl is 18 mass % or greater, among repeating units derived from a diene, a proportion of a vinyl structure is 8 mol % or less, a proportion of a 1,4-trans structure is 75 mol % or less, and a proportion of a 1,4-cis structure is from 17 to 90 mol %, and a glass transition temperature is &#x2212;60&#xb0; C. or lower.

Aromatic vinyl-diene copolymer, method for producing aromatic vinyl-diene copolymer, and rubber composition

The present invention is to provide a diene polymer that exhibits excellent low rolling resistance when used in a tire, a method for producing the diene polymer, and a rubber composition containing the diene polymer. The diene polymer of an embodiment of the present invention is produced by polymerizing a monomer containing at least a diene monomer by using an initiator prepared from an organolithium compound, an alkyl aluminum, and a metal alcoholate, and then terminating the polymerization by using an electrophile selected from the group consisting of titanium halides, tin halides, cyclic silazanes, alkoxysilanes, epoxides, amines, ketones, and compounds represented by Formula (N) below. 

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Hiratsuka, Japan

Yu Shinke