| 摘要 |
PURPOSE:To obtain a polyester compsn. having excellent moldability, transparency and slipperiness, by adding specified quantities of an alkaline earth metal salt, a phosphorus compd. and an alkali metal salt in the synthesis of a polyester and completing a polycondensation reaction. CONSTITUTION:In the synthesis of a polyester, an alkaline earth metal salt in a quantity represented by formula I is added to the reaction mixture when an esterification reaction is completed, and the mixture is stirred for 5-15min. A phosphorus compound in a quantity represented by formula II and an alkali metal salt in a quantity represented by formula III are then added thereto and a polycondensation reaction is completed. In the formulas, AE, P and A represent moles of the alkaline earth metal compd., the phosphorus compd. and the alkali metal compd. per mol of acid component constituting the polyester. Examples of the polyesters are polyethylene terephthalate and copolymers thereof wherein not more than 30mol% of a bifunctional carboxylic acid component, glycol component and hydroxycarboxylic acid component is copolymerized. |
