PRODUCTION METHOD OF THERMOPLASTIC COPOLYMER

PROBLEM TO BE SOLVED: To provide a production method of thermoplastic copolymer composition having superior heat resistance, colorless transparency and moldability and having superior dimensional stability in long-term use under severe conditions. SOLUTION: This production method of thermoplastic copolymer composition is characterized in that, when conducting: a step (a first step) for producing copolymer A including an unsaturated carboxylic acid alkyl ester unit (i) and an unsaturated carboxylic acid unit (ii); a step (a second step) for including a salt, heat-processing the copolymer A, and performing intramolecular cyclization by dehydration and/or dealcoholization reaction to produce the thermoplastic copolymer B including a glutaric anhydride unit (iii) and the unsaturated carboxylic acid alkyl ester unit (i) expressed in general formula (1); the content weight of the salt is not less than 0.01% and not more than 0.15% to the weight of the copolymer A. COPYRIGHT: (C)2009,JPO&INPIT