Ube Industries, Inc.

Kazuhiro Akikawa

Michinori Suzuki

Kenichi Hongyo

Nobuhiro Tsujimoto

Takefumi Yano

Kei Tsukahara

Yoshisuke Baba

Chikara Kotani

Nohiro Tsujimoto

A high cis-1,4-polybutadiene is produced, with reduced gel formation, by preparing a catalyst from (A) a cobalt compound, (B) a trialkyl (C.sub.1-10) aluminum compound, (C) a halide compound selected from those of formulae (1) and (2): (1) AlR.sup.2.sub.m X.sub.3-m, and (2) R.sup.3 --X, wherein R.sup.2 =C.sub.1-10 hydrocarbon, X=halogen, m=0 to 2, R.sup.3 =C.sub.1-40 hydrocarbon, and (D) water in an amount of 0.77 to 1.45 moles per mole of total Al in components (B) and (C); and polymerizing 1,3-butadiene in the presence of the resultant catalyst in a polymerization medium including an alkane, cycloalkane and/or olefin hydrocarbon.

Process for producing polybutadiene

A 1,2-polybutadiene composition having an excellent reinforcing effect for rubber and synthetic resin materials including at least two polybutadiene components different in melting point from each other and each having, as a main structure, a 1,2-polybutadiene structure, produced by polymerizing a 1,3-butadiene-containing monomer in a water-containing polymerization system in the presence of a catalyst comprising a transition metal compound, an organic compound of one of the Group I to III metals, and one of carbon disulfide, phenyl isothiocyanate, and xanthic acid compounds, while adding a melting point-regulating agent comprising at least one of ketones, aldehydes, alcohols, esters, nitriles, sulfoxides, amides, and phosphoric acid esters in one or two or more separate adding operations or a continuous adding operation.

Polybutadiene composition and process for producing same

A process for producing polybutadiene essentially consisted of syndiotactic-1,2-polybutadiene in an aqueous medium includes a step off polymerizing diene essentially consisted of 1,3-butadiene in the presence of: (A) a catalyst composition including (a) a transition metal compound, and (b) an organometallic compound which includes a metal selected from the elements consisting off groups 1, 2, 12, and 13 of Periodic Table; (B) an initiator comprising at least one component selected from a group consisting of carbon disulfide, an isothiocyanate compound, and a xanthogenic compound; and (C) an inert organic liquid having a density of at least 1.10, thereby resultant particles of syndiotactic-1,2-polybutadiene have a diameter up to 2 min.

Aqueous suspension polymerization of 1,3-butadiene to produce

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Ichihara, Japan

Kazuhiro Akikawa