| 摘要 |
PURPOSE:The titled copolymer, having polymer segments consisting essentially of plural vinyl aromatic hydrocarbons and polymer segments consisting essentially of a conjugated diene, a specific molecular weight ratio and melt index and improved transparency, impact resistance and surface hardness. CONSTITUTION:A block copolymer, obtained by reacting a vinyl aromatic hydrocarbon, e.g. styrene, with a conjugated diene, e.g. butadiene, in the presence of n-butyllithium as a catalyst in cyclohexane, and adding and reacting the vinyl aromatic hydrocarbon therewith, and having polymer segments consisting essentially of at least two vinyl aromatic hydrocarbons and polymer segments consisting essentially of at least one conjugated diene at 65/35-95/5 weight ratio between the vinyl aromatic hydrocarbons and the conjugated diene and 1.2-2.0 ratio between the weight-average and the number-average molecular weights of the vinyl aromatic hydrocarbon polymer blocks in the block copolymer and 2- 50g/10min melt flow index.
|
