Ube Industries, Inc.

Osamu Kimura

Nobuhiro Tsujimoto

Takashi Kitamura

Masato Murakami

Naomi Okamoto

Haruo Ueno

Mitsuharu Anbe

Hideo Ishikawa

Takashi Wada

Kohei Nakajima

Toshifumi Fukunaga

Satoshi Bandai

Kyohei Oizumi

Tetsuji Nakajima

Yoshisuke Baba

Hideyuki Aikawa

Jyun Yamashita

Takamasa Fujii

Shuichi Sakaue

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 polymer of ethylenically unsaturated monomer, for example, 1,3-butadiene, having a desired molecular weight and distribution thereof is produced, with a high stability, by preparing a solution of hydrogen in an inert organic solvent for the monomer in which a vapor-liquid phase equilibrium of hydrogen is attained, and then by addition-polymerizing the monomer in the hydrogen-dissolved inert organic solvent in the presence of a catalyst preferably including a metallocene complex of transition metal compound, an inert compound of a non-coordination anionic compound with a cationic compound, an organic metal (aluminum) compound and, optionally, water.

Method of producing a polymer

In a process for producing syndiotactic-1,2-polybutadiene by suspension polymerization wherein a mixture composed of 1,3-butadiene, a cobalt compound, and an organometallic compound or metal hydride containing a metal of group I, II or III of the periodic table is contacted with an initiator selected from the group consisting of carbon disulfide, phenyl isothiocyanate and xanthogenic compounds in an aqueous medium, the improvement comprising, after the preparation of the mixture, adding thereto an anti gelling agent selected from the group consisting of alcohols, aldehydes, ketones, carboxylic acid esters, nitriles, sulfoxides, amides and phosphoric acid esters, whereby the formation of a rubber-like gelation product in the mixture is inhibited.

Process for producing syndiotactic-1,2-polybutadiene

Butadiene polymers containing 70% or more of 1,2-structure and a relatively low melting point are produced by polymerizing 1,3-butadiene in the presence of a catalyst which has been prepared by admixing (A) an organic solvent solution containing 1,3-butadiene, a cobalt compound and an organoaluminium compound; (B) an amide compound of the formula (2) or (3): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are respectively an H atom, aliphatic hydrocarbon radical of 1 to 7 carbon atoms or aromatic hydrocarbon radical of 6 or 7 carbon atoms, R.sub.3 is H or an aliphatic hydrocarbon radical of 1 to 3 carbon atoms and n is 2 to 5, and; (C) carbon disulfide.

Method of producing 1,2-polybutadiene

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Ichihara, Japan

Osamu Kimura