Mitsubishi Chemical Corporation

Naoya Maeda

Takayuki Suzuki

Shinichiro Matsuzono

Hisashi Kimura

Hiromichi Matsui

Michiko Yoshida

Takeyuki Doi

The present invention is aimed to provide a method for producing a polyester with reduced CD content and elution amount, in which even after the production method, a reduction in physical properties of the polyester is small, and furthermore, a polyester having good moldability can be produced, and the present invention is concerned with a method for producing a polyester including an esterification reaction step of allowing an aliphatic diol and an aliphatic dicarboxylic acid to react with each other; a step of pelletizing a polyester obtained through the esterification reaction step; and a contact treatment step of bringing the obtained polyester pellets into contact with a mixed solution containing ethanol and water, wherein the mixed solution contains water in an amount of 10% by mass or more and not more than 99% by mass relative to the whole of the mixed solution.

Method for producing polyester

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)

Polyester resin particle and method for producing the same

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Mie, Japan

Naoya Maeda