RUBBER COMPOSITION FOR TIRE TREAD

摘要

PROBLEM TO BE SOLVED: To obtain a rubber composition for tire treads capable of highly balancing wet skid resistance with abrasion resistance by blending specific diene-based rubbers with a specified carbon black and an aromatic oil in a specific proportion. SOLUTION: This rubber composition is obtained by blending (A) 80-20 pts.wt. diene-based rubber having <=-50 deg.C glass transition temperature such as a polybutadiene rubber with (B) 20-80 pts.wt. diene-based rubber having -35 to 0 deg.C glass transition temperature such as a polyisoprene rubber and further blending a carbon black having 65-200m<2> /g N2 SA and 90-150mL/100g absorption volume of 24M4DBP and an aromatic oil and regulating the difference between the interaction parameter (χeff ) of mutual blended rubbers and the interaction parameter (χs ) at a spinodal point of the rubber blend system thereof within the range of 2.0×10-<4> to 1.2×10-<2> . The carbon black and the aromatic oil are blended in amount so as to provide a value ofϕdefined by the formula [C is the blended amount of the carbon black (pts.wt.);ρis the specific gravity of the rubber; S is the amount of the blended oils (pts.wt.)] with 0.48<=ϕ<=0.70.