Patent ID: 6313213
Filing Date: 2001-11-06
Classification: B60C,C08K,C08L

Abstract:
A rubber composition for a tire tread comprising:(1) (i) 60 to 90 parts by weight of at least one rubber selected from the group consisting of natural rubber and polyisoprene rubber, (ii) 10 to 35 parts by weight of a high cis polybutadiene rubber having a melt viscosity of 90 to 150 cps and a cis content of at least 90% by weight, and (iii) 0.5 to 5 parts by weight of an A-B type block copolymer composed of (A) a poly(styrene-butadiene) or polybutadiene block having a styrene content (St) of 0 to 35% by weight and a butadiene content (Bd) of 65 to 100% by weight, having a 1,2-vinyl bond content (Vn) of 5 to 80 mol %, and satisfying the relationship of Vn.ltoreq.2St+30 and (B) a polyisoprene block having a cis content of at least 70% by weight, in a ratio by weight (A)/(B) of 20 to 80/80 to 20, and(2) 40 to 60 parts by weight, based upon 100 parts by weight of the total rubber component, of carbon black having a nitrogen specific surface area (N.sub.2 SA) of at least 125 m.sup.2 /g.