STAR BLOCK COPOLYMER OF VINYLAROMATIC MONOMER WITH CONJUGATED DIENE, PRODUCTION OF SAME, AND COMPOSITION CONTAINING SAME AND CRYSTALLINE POLYSTYRENE

摘要

PURPOSE: To provide the subject copolymer having a specified structure, being excellent in transparency and blendability with PS and being useful for e.g. a PS resin composition having good transparency and mechanical properties. ;CONSTITUTION: There is provided the objective copolymer which is a star block copolymer having a structure of formula I [wherein X is a polyfunctional radical derived from a coupling agent such as a compound of formula II (wherein R¹ and R² are each an 8-30C alkyl; and n is 1-10); S₁ and S₂ are each an aromatic vinyl polymer block; B₂ is a conjugated diene polymer block; B₁/S₃ is an aromatic vinyl/conjugated diene random copolymer block, and 40-75 wt.% of B₁/S₃ are units derived from an aromatic vinyl monomer; and m and n are each a positive integer, provided that m+n means the functionality of X and is 3 or 4], wherein the total amount of B₂ is 40-90 wt.% based on the total weight of the conjugated diene contained in the star block copolymer.;COPYRIGHT: (C)1995,JPO