Mitsubishi Chemical Corporation

Takeyuki Doi

Hisashi Kimura

Naoya Maeda

Michiko Yoshida

The present invention provides a method for producing a polyester resin, comprising carrying out a hot-water treatment and a heat treatment, in this order, of polyester prepolymer particles obtained by melt polycondensation of a dicarboxylic acid component and a diol component. The hot-water treatment comprises bringing the polyester prepolymer particles with an intrinsic viscosity of from at least 0.10 dL/g to at most 1.0 dL/g and with a density of at most 1.36 g/cminto contact with hot water at a temperature higher than the glass transition temperature of the polyester prepolymer particles and less than 100&#xb0; C., under the condition satisfying the following formula (1):40&#x2266;()6000&#x2003;&#x2003;(1)

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Yokkaichi, Japan

Takeyuki Doi