| 摘要 |
PURPOSE:To obtain a polyester which has excellent moldability and gives moldings having excellent slipperiness, etc., by adding a phosphorus compd. and an alkali metal compd. after the completion of an esterification reaction, then adding an alkaline earth metal compd. and carrying out a polycondensation reaction. CONSTITUTION:Terephthalic acid or its ester-forming derivative, such as dimethyl terephthalate, and ethylene glycol are subjected to an esterification reaction or an ester exchange reaction in the presence of a catalyst. After the substantial completion of the reaction, a phosphorus compd. such as phosphoric acid or trimethyl phosphate and an alkali metal compd. such as lithium acetate or sodium propionate are added, and then an alkaline earth metal compd. such as calcium acatate or barium propionate is added. A polycondensation reaction is then carried out, thus obtaining a polyester mainly composed of an ethylene terephthalate unit as the main structural unit and contg. a large quantity of fine particles.
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