Other

Ube Industries, Inc.

Tetsuji Nakajima

Kiyoshige Muraoka

Noriko Yagi

Naomi Okamoto

Mitsuharu Anbe

Tokuji Inoue

Takashi Wada

Osamu Kimura

Takashi Kitamura

Jyun Yamashita

A process for producing a vinyl-cis-polybutadiene rubber, including mixing (A) vinyl-cis-polybutadiene obtained by (1) a step of adding a cis-1,4-polymerization catalyst obtainable from an organoaluminum compound and a soluble cobalt compound to a mixture containing 1,3-butadiene and a hydrocarbon-based organic solvent as the major components and having an adjusted water content, thereby subjecting the 1,3-butadiene to cis-1,4-polymerization and subsequently, (2) a step of making a catalyst obtainable from a soluble cobalt compound, an organoaluminum compound represented by the general formula, AlR(wherein R represents an alkyl group having from 1 to 6 carbon atoms, a phenyl group, or a cycloalkyl group), and carbon disulfide present in the resulting polymerization reaction mixture, thereby subjecting the 1,3-butadiene to 1,2-polymerization; and (B) cis-polybutadiene obtained by a step of adding the foregoing cis-1,4-polymerization catalyst, thereby subjecting the 1,3-butadiene to cis-1,4-polymerization and a rubber composition containing the resulting rubber.

Process for producing polybutadiene rubber and rubber composition

A modified diene elastomer prepared by a process comprising the steps of polymerizing a diolefin compound containing a conjugated double bond in a liquid phase in the presence of a cobalt compound, an organic aluminum compound containing a halogen atom, and water, to give a solution containing a diene elastomer, and reacting the diene elastomer with an elastomer-modifying compound is favorably employed for the manufacture of tire tread, particularly when it is employed in combination with silica as a filler.

Modified diene elastomer and its preparation

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Ichihara, Japan

Tetsuji Nakajima