Kuraray Co., Ltd.

Amyris, Inc.

Hiroshi Kanbara

Daisuke Koda

Satomi Ohta

Hiromi Maeda

Kei Hirata

Yosuke Uehara

Yoshikazu Ueno

Atsushi Inatomi

Junya Takai

Zhaoming Ma

A conjugated diene graft polymer having high transparency, heat resistance and weather resistance, and a method for producing the conjugated diene graft polymer. A method for producing a conjugated diene graft polymer in which a side chain (b) including a polymer including at least one monomer unit selected from a conjugated diene unit and an aromatic vinyl compound unit is bonded to a main chain (a) including a polymer including a conjugated diene unit, via a hetero atom Z serving as a branching point and having a valence of not less than 3, the method including reacting a specific active end polymer and a specific functional group-modified conjugated diene polymer having a functional group in a side chain to thereby produce a conjugated diene graft polymer; and recovering the conjugated diene graft polymer obtained.

Conjugated diene graft polymer and method for producing the same

The invention provides a modified liquid diene polymer that allows a rubber composition to give a crosslinked product which contains a filler in a dispersed state ideal for attaining enhanced properties and which also exhibits excellent properties such as wet grip and abrasion resistance. The invention also provides a rubber composition including the modified liquid diene polymer, a crosslinked product thereof, and a tire which includes a portion including the composition or the crosslinked product. The modified liquid diene polymer is a product of modification, with a specific silane compound, of a liquid diene block copolymer including a polymer block (b′1) or (b″1) containing butadiene units and a polymer block (b′2) or (b″2). The modified liquid diene polymer has a functional group derived from the silane compound, and satisfies specific conditions.

Modified liquid diene polymer and rubber composition

The invention provides a heavy-duty tire rubber composition excellent in wet grip performance and steering stability, and a tire tread, a bead filler, a tire belt and a heavy-duty tire which each partially include the composition. The heavy-duty tire rubber composition includes 100 parts by mass of a solid rubber (A), 0.1 to 50 parts by mass of a modified liquid diene rubber (B) having a functional group derived from a silane compound with a specific structure, and 20 to 200 parts by mass of a filler (C), the modified liquid diene rubber (B) satisfying the following (i) and (ii): (i) the weight average molecular weight (Mw) is not less than 1,000 and not more than 120,000, and (ii) the vinyl content is not less than 30 mol % and less than 70 mol %.

Heavy-duty tire rubber compositions and tires

Disclosed herein is a rubber composition containing 100 parts by mass of a solid rubber (A), 0.1 to 50 parts by mass of a modified liquid diene rubber (B) having a functional group derived from a silane compound represented by the formula (1), and 20 to 200 parts by mass of a filler (C), the modified liquid diene rubber (B) satisfying (i) to (iii): (i) a weight average molecular weight (Mw) is not less than 1,000 and less than 15,000; (ii) a vinyl content is not more than 70 mol %; and (iii) an average number of functional groups per molecule of the modified liquid diene rubber (B) is 1 to 20.

Rubber compositions

A rubber composition includes 100 parts by mass of a solid rubber (A), 0.1 to 50 parts by mass of a modified liquid diene rubber (B) having a functional group derived from a silane compound represented by the formula (1), and 20 to 200 parts by mass of a filler (C), the modified liquid diene rubber (B) satisfying (i) to (iii) below: (i) The weight average molecular weight (Mw) is 15,000 to 120,000. (ii) The vinyl content is not more than 70 mol %. (iii) The average number of functional groups per molecule of the modified liquid diene rubber (B) is 1 to 30.

The invention relates to a rubber composition having a good processability, and simultaneously having a rolling resistance performance and hardness after vulcanization at high levels, with which the contamination of the mold for processing due to the bleeding-out of the plasticizer can be suppressed, and in which the migration of the plasticizer and so on is suppressed to a low level; a vulcanized rubber obtained by vulcanizing the rubber composition; and to a tire including the rubber composition as at least a part thereof. The rubber composition contains 100 parts by mass of rubber component (A) composed of at least one of a synthetic rubber and a natural rubber, 0.1 to 50 parts by mass of a diene polymer (B), 20 to 150 parts by mass of a filler (C), 0.1 to 10 parts by mass of a vulcanizing agent (D), 0.1 to 15 parts by mass of a vulcanization accelerator (E) and 0.1 to 15 parts by mass of vulcanization aid (F).

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Kamisu, Japan

Hiroshi Kanbara