| 摘要 |
PURPOSE:To provide the titled copolymer having specific composition and thermal properties and excellent impact resilience, wet-skid resistance and abrasion resistance, by copolymerizing styrene and butadiene in the presence of a Lewis base and an organic Li compound, and adding a polyfunctional coupling agent to the copolymer. CONSTITUTION:Styrene is copolymerized with butadiene using an organic Li compound as a polymerization initiator in a hydrocarbon solvent containing a Lewis base, and the resultant copolymer is added and reacted with a polyfunctional coupling agent having >=3 reactive sites to obtain the objective copolymer characterized in that the Mooney viscosity (ML1+4, 100 deg.C) is 30-150, the ratio of the weight-average molecular weight MW to the number-average molecular weight MN (MW/MN) is 1.3-3.0, the vinyl bond content in the butadiene segment is 16-48%, the bonded styrene content is 10-45wt%, the amount of the chain consisting of single styrene unit is 65wt% of whole styrene units, the amount of the long styrene chain consisting of >=8 styrene units is <=5.0wt% of the whole styrene units, and the temperature difference between the deflection points in the glass transition temperature zone of an endothermic curve is >=15 deg.C measured by a differential scanning calorimeter (DSC).
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