| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polyester which is produced by using a polycondensation catalyst comprising a metal component except antimony and germanium as the main component of the catalyst, to provide a continuous polycondensation method with which filter and nozzle clogging by foreign matters during molding, transparency, yellowing, heat resistance, etc., are improved and which is stable and to obtain a product thereof. SOLUTION: In this method for producing a polyester by continuous condensation polymerization by using an oligomer obtained by direct esterification reaction or transesterification reaction between an aromatic or aliphatic dicarboxylic acid or its ester derivative and a diol or its ester derivative, the method for continuous polycondensation of a polyester comprises adding a polyester polycondensation catalyst which is selected from at least aluminum compounds and cobalt compounds and has satisfies conditions of a specific Al/Co molar ratio and Co concentration under conditions of specific oligomer Pn (polymerization degree). |
