| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently producing a polyester composition scarcely having an oligomer content and suitable for production of a thick film. SOLUTION: The invention relates to a method for producing a polyester composition (B) having intrinsic viscosity and a polymer powder content appropriate for producing a film and a reduced content of oligomers, by subjecting a polyester composition (A) comprising a dicarboxylic acid component mainly composed of terephthalic acid or its ester-forming derivatives and a diol component mainly composed of ethylene glycol, to a heat treatment in a temperature range between 205°C and 235°C, by circulating a heated inert gas in a fluidized type vertical heat treatment device provided with an agitator. COPYRIGHT: (C)2008,JPO&INPIT
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