Polyester polymerization catalyst, polyester produced therewith and process for producing the polyester

摘要

The invention provides a polyester produced in the presence of a polycondensation catalyst comprising at least one compound selected from a group consisting of aluminum compounds and at least one compound selected from a group consisting of phosphorus compounds and being excellent in color tone, thermal stability, and transparency and improved in terms of insoluble particles. Particularly, the invention provides a polyester in which the content of an aluminum containing insoluble particles in the polyester is 3500 ppm or lower and a polyester which has a haze value of 2% or lower when being formed into a monoaxially oriented film. The aluminum catalyst for attaining these characteristics and properties may be polyester polymerization catalyst obtained by mixing an aluminum compound and a phosphorus compound in a solvent and has specified spectral characteristics in the side measurement of ³¹P-NMR spectrum and ²⁷Al-NMR spectrum.