| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition for a tire tread improving abrasion resistance and crack growth resistance without deteriorating both wet properties (frictional resistance on wet road surfaces) and low heat-buildup properties and to provide a pneumatic tire using the rubber composition in the tread. SOLUTION: The rubber composition for the tire tread comprises 20-100 pts.mass of a reinforcing filler based on 100 pts.mass of a rubber component composed of 20-80 pts.mass of a solution-polymerized styrene-butadiene copolymer rubber having a micro-structure satisfying the following numerical formulas (1) to (4): (1) Vi≥ST, (2) Vi+2ST≥80, (3) Vi≤70, and (4) ST≤50 äwherein, ST represents the bonded styrene content (mass%) in the copolymer rubber; and Vi represents the 1,2 bond content (%) in the bonded butadiene} and 20-80 pts.mass of a polybutadiene rubber having a micro-structure represented by the following numerical formula (5): (5) Vi≤0.25×(cis-97) äwherein, Vi represents the 1,2 bond content (%) in the bonded butadiene; and cis represents the cis-1,4 bond content (%)} and≥92% cis-1,4 bond content. COPYRIGHT: (C)2007,JPO&INPIT
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