| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject composition capable ofspecifying the relationship of the average glass transition temperature of plural material rubbers, and improving balance of tanδ, reducing a fuel cost of general-purpose/HPT-based tire tread, having as much tanδreducing effect using an inexpensive polymer SBR as that by melt polymerization. SOLUTION: In blending 100 pts.wt. of a raw material rubber comprising (A) 50-90 pts.wt. of a raw material rubber mixture containing 20-80wt.% of a diene-based rubber having a modified and/or coupled diene and (B) 50-10 pts.wt. of a raw material rubber composed of at least one diene-based rubber having an unmodified end with (C) 50-120 pts. wt. of a reinforcing agent and (D) 20-80 pts.wt. of a softener, the average glass transition temperature TgA ( deg.C) of the component A and that TgB ( deg.C) of the component B have the relationship of the formula. The component A is mixed with >=80wt.% of the component C at >=135 deg.C and the mixture and then blended with the component B, the rest of the component C and the component D.
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