METHOD OF TREATING POLYESTER POLYMER AND POLYESTER POLYMER REDUCED IN LOW-BOILING COMPONENT CONTENT

摘要

A method for treating a polyester polymer according to the present invention is toheat apolyesterpolymer (C) , which is obtained by ring-opening polymerization of a polymer (A) having hydroxyl and/or ester bonds and cyclic esters (B) containing epsilon -caprolactone, in a solid state at a temperature that is not lower than 115 DEG C and lower than 170 DEG C and is lower than the melting point of the polyester polymer (C) in order to remove an organic low-boiling component (v) from the polymer (C) obtained by the polymerization. According to the present invention, there is obtained a polyester polymer in which epsilon -caprolactone and caprolactone dimer in polyester polymers are fully removed without causing deterioration or change of the physical properties of resins and further without causing deterioration of their colors and a decrease in cost effectiveness.