| abstract |
A thermoplastic copolymer having excellent thermal resistance and transparency and high mechanical strengths, and comprising a terpolymer composed of 30 to 70 % by weight of aromatic vinyl compound units, 4 to 40 % by weight of vinyl cyanide units and 26 to 50 % by weight of N-substituted maleimide units. The copolymer has a narrow distribution of the copolymer composition for GPC, is substantially free from acetone insolubles, has a weight-average molecular weight of 100,000 to 300,000 and a number-average molecular weight of 50,000 to 150,000, and contains at most 50 ppm of residual unreacted substituted maleimide. This copolymer can be produced efficiently by the method of this invention. A thermoplastic resin composition comprising this copolymer gives a molding having excellent heat and chemical resistances and high impact strength and being suitable as a material of the interior furnishings of an automobile and the components of electric and electronics appliances. |