| 摘要 |
PURPOSE:To obtain a polyester having high intrinsic viscosity and excellent color tone in a short time, by mixing and reacting a specific amount of a lower fatty acid anhydride to an aromatic oxycarboxylic acid and a polyalkylene terephthalate. CONSTITUTION:The objective polyester having an intrinsic viscosity of >=0.5dl/g can be produced by mixing (A) an aromatic oxycarboxylic acid of formula (Ar is aromatic group) (e.g. 4-hydroxybenzoic acid) with (B) a polyalkylene terephthalate having an intrinsic viscosity of <=0.2dl/g at a molar ratio (A:B) of preferably 5:95-95:5, adding (C) a lower fatty acid anhydride (e.g. acetic anhydride) at an amount larger then the sum of the equivalent numbers of whole hydroxyl groups of the components A and B, starting the reaction e.g. in an inert atmosphere at <=150 deg.C, raising the reaction temperature to 230-290 deg.C and continuing the reaction under reduced pressure.
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