| 摘要 |
PURPOSE:The titled composition excellent in road surface grip, haet resistance, abrasion resistance and breaking strength, by adding a specified conjugated diene monovinyl aromatic hydrocarbon copolymer to a rubber such as a diene rubber. CONSTITUTION:A predetermined amount of a conjugated diene compound is copolymerized with a monovinyl aromatic hydrocarbon by using an organic lithium compound as an initiator to obtain a conjugated diene monovinyl aromatic hydrocarbon copolymer of vinyl bond percentage of conjugated diene unit of 50-95% and a monovinyl aromatic hydrocarbon unit content of 10-50wt% (e.g., a butadiene styrene copolymer in which the centent of chains composed of a least nine combined styrene units is 50% or below based on the total styrene units). 30wt% or above this copolymer is added to, e.g., a diene rubber of a glass transition temperature >=-60 deg.C. To this mixture, if necessary, 60-200pts.wt. carbon black of an average particle diameter >=300Angstrom and 30-200 pts.wt. process oil of a viscosity-gravity constant of 0.900-0.999 are added per 100pts.wt. rubber to obtain the titled composition of a 200% tensile modulus of 5-50kgf/cm<2> and a value of integral of a loss tangent with temperature, of the expression, of 15-56.
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