| abstract |
A polycondensation catalyst for polyester production according to an ester exchange reaction or esterification reaction between a glycol and a dicarboxylic acid or ester forming derivative thereof, which polycondensation catalyst is composed of solid base particles comprising 100 parts by weight of solid base and either 0.1 to 50 parts by weight, in terms of TiO2, of coating layer of titanic acid, or, at the surface thereof, 0.1 to 50 parts by weight, in terms of TiO2, of outer coating layer of titanic acid together with 1 to 20 parts by weight of inner coating layer. The inner coating layer consists of either an oxide of at least one element selected from among silicon, aluminum and zirconium, or a composite oxide at least two elements selected from among silicon, aluminum and zirconium. This catalyst exhibits excellent catalytic activity although not containing antimony as a component, providing a high-molecular-weight polyester with excellent color tone and transparency. |