Ube Industries, Inc.

Mitsuharu Anbe

Naomi Okamoto

Masato Murakami

Koji Shiba

Takashi Wada

Michinori Suzuki

Masahiro Tanaka

Takeshi Shoda

Osamu Kimura

Tetsuji Nakajima

Takashi Kitamura

Jyun Yamashita

A method for producing a conjugated diene polymer having a high content of cis-1,4-structures with a high activity, a conjugated diene polymer, and a modified conjugated diene polymer. The catalyst for conjugated diene polymerization in the method includes: a non-metallocene type gadolinium compound (A) represented by the general formula (1); an ionic compound (B) formed of a non-coordinating anion and a cation; and an organic metal compound (C) of an element selected from the group consisting of a group 2, a group 12, and a group 13 of the periodic table.

Method of producing a conjugated diene polymer, a modified conjugated diene polymer, and a vinyl cis-polybutadiene composition

A conjugated diene polymer having a high content of cis-1,4-structures with a high activity, a conjugated diene polymer and a modified conjugated diene polymer using the same, a rubber composition for a tire, and a rubber composition for a rubber belt. Described are a catalyst for a conjugated diene polymerization including: a non-metallocene type gadolinium compound (A) represented by the general formula (1); an ionic compound (B) formed of a non-coordinating anion and a cation; and an organic metal compound (C) of an element selected from the group consisting of a group 2, a group 12, and a group 13 of the periodic table, a conjugated diene polymer and a modified conjugated diene polymer obtained using the same, a rubber composition for a tire, and a rubber composition for a rubber belt.

Conjugated diene polymer and modified conjugated diene polymer produced using the same, rubber composition for tire, and rubber composition for rubber belt

The object is to provide a rubber composition for a high-strength golf ball which has a high hardness, high resiliency, excellent processability and improved filler dispersibility, by adjusting each of the Mooney viscosity, the molecular weight distribution and the n value (the rate-dependent index for Mooney viscosity) of a high-cis-polybutadiene rubber using a cobalt catalyst to a value falling within a specific range. The rubber composition comprises 100 parts by weight of a high-cis-polybutadiene synthesized using a cobalt catalyst and 10 to 50 parts by weight of a co-crosslinking agent, wherein the high-cis-polybutadiene satisfies the following requirements (a) to (c): (a) the Mooney viscosity (ML) is 40 to 55; (b) the molecular weight distribution [a weight average molecular weight MW)/a number average molecular weight (Mn)] is 3.0 to 4.2; and (c) the rate-dependent index of Mooney viscosity (n value) is 2.3 to 3.0.

Rubber composition for golf ball and golf ball

Provided by using a catalyst containing an yttrium compound is conjugated diene polymer with very low solution viscosity, improved workability, high degree of branching, and high content of cis-1,4 structures. Also provided is a rubber composition utilizing the polymer and allowing excellent dispersion of reinforcing agent. According to a method of manufacturing a conjugated diene polymer characterized by polymerizing a conjugated diene at 50 to 120&#xb0; C. in the presence of a catalyst obtained from (A) an yttrium compound, (B) an ionic compound consisting of a non-coordinating anion and a cation, and (C) an organoaluminum compound, the conjugated diene polymer has the following characteristics that: (1) a ratio (T/ML) between a 5 wt % toluene solution viscosity (T) measured at 25&#xb0; C. and a Mooney viscosity (ML) at 100&#xb0; C. is 0.1 to 1.2; and (2) a content of cis-1,4 structures is 80% or higher, and a content of 1,2 structures is lower than 5%.

Conjugated diene polymer manufacturing method, polybutadiene, and rubber composition utilizing the same

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

The rubber composition of the invention includes a rubber composition which is a silica compounded rubber composition for tire containing 100 parts by weight of a rubber component made of (a) from 20 to 80% by weight of a vinyl-cis-polybutadiene rubber containing 1,2-polybutadiene having a melting point of 170&#xb0; C. or higher and a high-molecular substance having at least one unsaturated double bond per a repeating unit and comprising at least one member selected from polyisoprene, crystalline polybutadiene having a melting point of not higher than 150&#xb0; C., liquid polybutadiene and derivatives thereof and (b) from 80 to 20% by weight of a diene-based rubber other than (a); and (c) from 40 to 100 parts by weight of a rubber reinforcing agent containing 40% or more of silica, wherein the 1,2-polybutadiene is dispersed in a short crystalline fiber state and the high-molecular substance is dispersed in a granular state in the cis-polybutadiene rubber which is a matrix component of the subject vinyl-cis-polybutadiene rubber (a); and the short crystalline fiber of the 1,2-polybutadiene is dispersed in particles of the high-molecular substance.

Rubber composition

The invention has an object to provide a rubber composition for tire with improved processability and abrasion resistance. The invention relates to a rubber composition for tire, comprising: (a) 5-90 weight parts of a high cis polybutadiene having a cis structure in a proportion of 95 wt % or higher in a microstructure analysis; (b) 90-5 weight parts of a diene-based rubber other than (a); and (c) 1-100 weight parts of a reinforcing agent blended in 100 weight parts of a rubber component including (a)+(b). The high cis polybutadiene is synthesized using a cobalt-based catalyst and satisfies the requirements of: (i) a Mooney viscosity (ML) of 40-49; (ii) a molecular weight distribution [Weight average molecular weight (Mw)/Number average molecular weight (Mn)] of 3.0-3.9; and (iii) a velocity dependence index (n-value) of the Mooney viscosity of 2.3-3.0.

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Ichihara, Japan

Mitsuharu Anbe