PURPOSE: To obtain a polybutadiene rubber composition consisting of a specific polybutadiene rubber and a natural rubber, etc., excellent in elasticity, hardness, durability, fluidity and moldability and suitable as vibration-proof rubber, etc.
CONSTITUTION: This composition consists of (A) preferably ≥20% polybutadiene rubber composed of (i) 1-25wt.% boiled n-hexane-insoluble matter having 0.5-4 reduced viscosity and (ii) 99-75wt.% boiled n-hexane-soluble matter having 300000-800000 weight-average molecular weight(Mw) and satisfying the formula t-cp<2ML-10 in the relationship between toluene solution viscosity (t-cp) and Mooney viscosity (ML) at 100°C and (B) preferably ≤80% natural rubber and/or one or more kinds of diene based synthetic rubber.
NAKAMURA HIROYUKI
TANAKA TSUNEO
