RUBBER COMPOSITION FOR TIRE TREAD

摘要

PURPOSE:To obtain the titled rubber composition giving a tire having excellent abrasion resistance and wet-grip performance and good low-temperature characteristics, by compounding carbon black and a petroleum-based softener to a rubber mixture composed of BR two kinds of SBR having different glass- transition temperature (Tg). CONSTITUTION:The objective composition having a storage shear modulus of <=500MPa at -30 deg.C can be produced by compounding (A) 100pts.wt. of a stock rubber consisting of a mixture of (A1) one or more styrene/butadiene copolymer rubbers (SBR) having a Tg of -20--40 deg.C, (A2) one or more styrene/ butadiene copolymer rubbers having a Tg of -40--70 deg.C and (A3) a polybutadiene rubber having a Tg of <=-70 deg.C with (B) 70-130pts. of carbon black having a specific surface area of >=120m<2>/g measured by nitrogen- adsorption method and (C) 20-120pts. of a petroleum-based softener having a viscosity gravity constant of 0.90-0.98. The stock rubber is produced by mixing 10-50pts. of A1, 20-60pts. of A2 and 10-50pts. of A3.