| 摘要 |
PURPOSE:To obtain a rubbery polymer composition which can give a resin composition of an improved balance between impact resistance and loss when added to a rigid resin by polymerizing an aromatic vinyl monomer with a conjugated diene monomer in the presence of an organic alkali catalyst by using special reaction steps. CONSTITUTION:The title composition comprising 98-85wt.% aromatic vinyl/ conjugated diene block copolymer and 2-15wt.% aromatic vinyl homopolymer is obtained by subsequently polymerizing an aromatic vinyl monomer (A) with a conjugated diene monomer (B) in an A to B weight ratio of 25:75 to 55:45 in the presence of 0.1-10mmol, per 100g of the monomer mixture, of an organic monoalkali metal catalyst as a polymerization catalyst by the following steps. 40-100wt.% of the conjugated diene monomer is polymerized in the presence of 20-95mol% of the organic monoalkali metal catalyst to form an active conjugated diene polymer (step 1); the rest of the conjugated diene monomer and 0-80wt.% of the aromatic vinyl monomer are added to the polymerization system optionally containing the above polymer and polymerized (step 2); and the above rubbery polymer composition is obtained (step 3). |
