Ube Industries, Inc.

Bridgestone Corporation

Sumitomo Rubber Industries Limited

Takeshi Shoda

Naomi Okamoto

Yuuto Kanou

Mitsuharu Ambe

Takahiro Mabuchi

Masato Murakami

Toshifumi Haba

Koji Shiba

Mitsuharu Anbe

Koji Ohkawa

The present invention provides a rubber composition for a tire having improved workability and abrasion resistance. A rubber composition for a tire according to the present invention comprises: a polybutadiene which has: (A) a Mooney viscosity (ML) being 43 or more; (B) a ratio (Tcp/ML) of 5 wt % toluene solution viscosity (Tcp) to Mooney viscosity (ML) being 0.9 to 2.3; (C) a stress relaxation time (T80) being 10.0 to 40.0 seconds, which is a time until a torque is attenuated by 80% when the torque at the end of MLmeasurement is 100%; and (D) a molecular weight distribution (Mw/Mn) being 2.50 to 4.00; another rubber (ii); and a rubber reinforcing material (iii).

Rubber composition for tire

The present invention provides a polybutadiene having improved workability and abrasion resistance. A polybutadiene according to the present invention has: (A) a Mooney viscosity (ML) being 43 or more; (B) a ratio (Tcp/ML) of 5 wt % toluene solution viscosity (Tcp) to Mooney viscosity (ML) being 0.9 to 2.3; (C) a stress relaxation time (T80) being 10.0 to 40.0 seconds, which is a time until a torque is attenuated by 80% when the torque at the end of MLmeasurement is 100%; and (D) a molecular weight distribution (Mw/Mn) being 2.50 to 4.00.

Polybutadiene

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

Rubber composition

A liquid rubber composition including a 1,2-polybutadiene resin component dispersed in the form of fine particles in a liquid rubber component in a weight ratio of 1:100 to 50:100 has a high dispersion stability and a low specific gravity and is useful for forming a cured rubber article having a high elastic modulus and a satisfactory mechanical strength and ultimate elongation.

Liquid rubber composition

Growing community of inventors

Ichihara, Japan

Takeshi Shoda