Patent ID: 9206286
Filing Date: 2015-12-08
Classification: C08G,Y02P

Abstract:
1. A method for producing a polyester resin comprising a dicarboxylic acid unit and a diol unit, wherein at least a portion of the diol unit is a diol unit having a cyclic acetal skeleton, the method comprising the following steps (1) to (4-2): step (1) of reacting any one or more compounds selected from the group consisting of a dicarboxylic acid (G), a polyester resin comprising a dicarboxylic acid (G) and a diol (B) having no cyclic acetal skeleton, and a dicarboxylic acid dialkyl ester (E), with a diol (B) having no cyclic acetal skeleton to obtain a dihydroxyester (F) represented by the following formula (1); step (2) of subjecting the dihydroxyester (F) to transesterification reaction with a diol (A) having a cyclic acetal skeleton to obtain an oligomer; step (3) of polymerizing the oligomer; step (4-1) of distilling off a diol mixture (C) comprising the component (B) and/or the component (A) in the step (2) and/or the step (3), and decomposing the component (C) under a pH condition of 10 or lower such that a concentration of the component (A) in the component (C) is 0.5% by mass or lower; and step (4-2) of distilling the component (C) after the step (4-1) to obtain a purified diol (B1) comprising the component (B): (wherein R