| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a block copolymer composition or its hyrogenation product which gives styrenic resin blend injection molded articles having good impact resistance and rigidity and having relatively uniform mold shrinkage coefficients in an injection direction and in a direction crossing the injection direction. SOLUTION: This method is for producing the block copolymer composition which is produced from a vinyl aromatic hydrocarbon and a conjugated diene, or its hydrogenation product, the composition comprising a component (a) and a component (b) bound with a tri- or more-functional coupling agent, which have different molecular weights. The method is characterized by adding the coupling agent in an amount of the less stoichiometric number than the number of polymerization active terminals in the course of the polymerization to produce the component (b), and then continuing the polymerization reaction to produce the component (a). COPYRIGHT: (C)2009,JPO&INPIT
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