Bridgestone Corporation

Youichi Ozawa

Noriko Endou

Hajime Kondou

A process for producing a conjugated diene-based polymer which comprises, in the first modification, modifying a conjugated diene-based polymer having active chain ends, which is obtained by polymerizing a diene-based monomer singly or with other monomers and has a content of a cis-1,4 unit of 75% by mole or greater in the conjugated diene portion of the main chain, by reacting the active chain ends with a hydrocarbyloxysilane compound and reacting the modified polymer with a specific compound such as a hydrocarbyloxysilane compound, and a rubber composition containing the polymer modified in accordance with the above process and, preferably, 10 to 100 parts by weight of silica and/or carbon black per 100 parts by weight of the rubber component containing the modified polymer, are provided. The rubber composition containing silica and/or carbon black exhibits improved fracture properties, abrasion resistance, low heat buildup property and excellent workability. A process for producing a conjugated diene-based polymer exhibiting improved cold flow, a polymer produced in accordance with the process, and a rubber composition and a tire using the polymer are also provided.

Conjugated diene polymer, process for its production and rubber compositions containing the same

The present invention relates to a process for producing a modified polymer, comprising modifying a polymer having an active site of an organometal type in a molecule by reacting the site thereof with a hydrocarbyloxysilane compound and adding a condensation accelerator to the reaction system in the middle of the above reaction and/or after completion thereof and a rubber composition comprising the modified polymer obtained by the process described above, preferably a rubber composition comprising 100 parts by weight of (A) a rubber component containing at least 30% by weight of the above modified polymer and 10 to 100 parts by weight of (B) silica and/or carbon black.

Process for producing modified polymer, modified polymer obtained by the process, and rubber composition

Provided is a process for producing a modified polymer, characterized by carrying out primary modification in which a hydrocarbyloxysilane compound is reacted with the active site of a polymer having an active site of an organic metal type in a molecule and then carrying out secondary modification in which the hydrocarbyloxysilane compound is further reacted therewith. This makes it possible to provide a modified polymer which enhances interactions with silica and carbon black when used for both of silica-blended and carbon black-blended rubber compositions and which elevates the fracture characteristic, the abrasion resistance and the low heat buildup property at the same time and can exhibit a good workability.

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Tokyo, Japan

Youichi Ozawa