| 摘要 |
PURPOSE:To improve the low-temperature impact resistance, weathering resistance and coating properties by hydrogenating a specific block copolymer to make it useful as modifier for rubbers and as modifier to improve the impact resistance of resins. CONSTITUTION:An aromatic vinyl compound (a), and if desired, 1,3-butadiene (b) are polymerized in a hydrocarbon solvent in the presence of an organolithium initiator to produce a polymer block comprising mainly the component (a). The component (b) and a polar compound (c) are added to the product and are polymerized to produce a block copolymer which comprises 10-50wt.% polymer block (A) comprising 90wt.% or more component (a), 30-80wt.% polybutadiene polymer block (B) comprising 30-70% 1,2-vinyl linkage, and 5-30wt.% polybutadiene polymer block (C) comprising 30% or less 1,2-vinyl linkage, or a block copolymer wherein block copolymer units are bonded to polymer units comprising one or more polymer blocks of (A)-(C) via coupling agent residues thereby extending or branching the molecular chains of the polymer. The obtained copolymer is hydrogenated to produce the title copolymer which has a number-average molecular weight of 40,000-700,000 and wherein 80% or more of the olefinically unsaturated bonds are hydrogenated. |
