SILICA-MIXED RUBBER COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain a composition showing good silica dispersion and possessing satisfactory mechanical strength by making a conjugated-diene-based elastomer contain a specific amount of silica and a specific amount of a polymer silane coupling agent obtained by adding a specific silane compound to a butadiene- based elastomer. SOLUTION: A conjugated diene-based elastomer is a rubbery polymer containing a conjugated diene as a major component. Silica to be used preferably has specific surface area of 50-400 m2/g. An amount of silica is referably 10-100 pts.wt. per 100 pts. of the elastomer and an amount of a silane coupling agent is 1-30 pts.wt. per 100 pts.wt. of the elastomer. The specific silane compound is represented by formula (R1 is 1-6C divalent alkylene group; and R2-R4 are methoxy, methyl and the like provided that at least one of R2-R4 is methoxy or phenoxy) and such an example is 3-mercaptopropyltrimethoxysilane. The coupling agent is obtained by adding 10-300 pts.wt. of the silane compound to 100 pts.wt. of a butadiene-based polymer having number average molecular weight of 500-10,000.