| abstract |
(57) [Abstract] [Purpose] The present invention has excellent wear resistance in a state where physical properties such as hardness and modulus of a vulcanized product are retained, and particularly, road graspability, heat resistance, and wear resistance. Provided is a rubber composition for a tire tread, which is required to have an antithetical property of property. In a pneumatic tire having a tread portion, a styrene-butadiene copolymer obtained by using at least an organolithium polyfunctional initiator and / or an organomonolithium initiator and a polyfunctional monomer, wherein a) a styrene bond content is 30-55% by weight, b) glass transition temperature of -40 ° C or higher, c) 40 in terms of polystyrene-equivalent molecular weight of 1,000,000 or more The nitrogen adsorption specific surface area (N 2 SA) is 100 parts by weight of a blend rubber containing 10% by weight or more of a copolymer having a polystyrene conversion molecular weight of 250,000 or less by weight of 12% by weight or more. It is composed of 60 to 250 parts by weight of carbon black of 105 to 250 m 2 / g. |