| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a polyester in which an intrinsic viscosity is low and a content of a cyclic trimer, i.e., a main component of a cyclic oligomer is slight. Ž<P>SOLUTION: The manufacturing method for the polyester is characterized in that a crude polyester having the intrinsic viscosity of 0.50-0.70 dl/g obtained by a poly-condensation reaction of a dicarboxylic acid component and a glycol component is subjected to heat treatment at a temperature 180°C or less to a melting point of the polyester while circulating a moisture-adjusted inert gas having a moisture content of at least 3.5 g/Nm<SP>3</SP>at a flow rate of 1 liter or more to 10,000 liter or less per hr based on 1 kg crude polyester such that variation of a limiting viscosity of the polyester satisfies the following equation: -0.05 dl/g≤(limiting viscosity before heat treatment)-(limiting viscosity after heat treatment)≤0.05 dl/g. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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