Patent ID: 9289749
Filing Date: 2016-03-22
CPC Classification: B01J,C08G

Claim Text:
1. A polycondensation catalyst for producing polyester by an esterification reaction or a transesterification reaction between a dicarboxylic acid or an ester-forming derivative thereof and a glycol, wherein the polycondensation catalyst comprises particles of a solid base having on the surfaces an inner coating layer of titanic acid in an amount of from 0.1 to 50 parts by weight in terms of TiO 2 per 100 parts by weight of the solid base, and an outer coating layer either of an oxide of at least one element selected from aluminum, zirconium and silicon, or of a composite oxide of at least two elements selected from aluminum, zirconium and silicon on the surface of the inner coating layer in an amount of from 1 to 50 parts by weight per 100 parts by weight of the solid base.