| 摘要 |
PURPOSE:To obtain the titled polyester having a high intrinsic viscosity and improved hue, by blending a polyester with an acyloxy aromatic carboxylic acid and an acid anhydride and carrying out polymerization. CONSTITUTION:(A) An acyloxy aromatic carboxylic acid expressed by the formula (Ar is aromatic group; R is 2-5C acyl), e.g. acetic acid ester of 4- hydroxybenzoic acid, etc., is blended with (B) anhydride of a 2-5C lower fatty acid, e.g. acetic anhydride, etc., in an equivalent amount of 0.01-0.50 based on the component (A) in an inert atmosphere and the resultant blend is added to (C) a polyester, consisting essentially of an alkylene terephthalate and having >=0.2dl/g intrinsic viscosity, e.g. polyethylene terephthalate, etc., to give preferably 5-95mol% component (A) based on unit mol component (C) and dissolved while heating at, e.g. 210-300 deg.C. Polycondensation is then carried out to afford the aimed polyester having >=0.5dl/g intrinsic viscosity.
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