| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition useful for a tire tread, etc., capable of manifesting grip on ice or snow, processability and low shrink properties, comprising specific conjugated diene (co)polymers different in molecular weight in a prescribed ratio. SOLUTION: This rubber composition comprises (A) a conjugated diene polymer (P1 ) or (P2 ) a vinyl aromatic hydrocarbon-conjugated diene copolymer having >=30×10<4> weight-average molecular weight (Mw) converted to that of polystyrene and <=30wt.% of bonded styrene amount (S) and (B) the polymer P1 or the copolymer P2 having 0.2×10<4> to 8×10<4> Mw and <=30wt.% of bonded styrene amount S. The components A and B satisfy the relation of the formula S+(V/2)<25 [V is a vinyl content (%)] and the composition is composed of 30-120 pts.wt. of the component B based on 100 pts.wt. of the component A. The composition is regulated to have >=15% extract content with chloroform after the vulcanization of the composition based on the weight of the component B.
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