| 摘要 |
<p>A styrene-butadiene copolymer having excellent low hysteresis loss characteristic, wet skid resistance, fracture characteristics, and abrasion resistance and a rubber composition comprising the copolymer are provided. The styrene-butadiene copolymer has a total styrene content in the range of 33 to 42 % by weight of the styrene-butadiene copolymer; a content of styrene sequences having 4 to 20 styrene units in the range of 40 to 65 % by weight of the total styrene content, as obtained by measurements by NMR and GPC; a content of styrene sequences having more than 20 styrene units in the range of 5 % by weight or less of the total styrene content, as obtained by measurement by GPC; a content of vinyl unit in the range of 30 % by mol or less of a butadiene part of the styrene-butadiene copolymer; a sum of the total styrene value and 1/2 of the content of vinyl units in the range of 46 to 52 %; and an inner or end structure having, for example, tin-carbon bond. The copolymer and the rubber composition are used for tire treads and the like. <IMAGE></p> |
