| abstract |
The present invention is to provide a catalyst for producing polyester that can produce polyester with high catalytic activity and a method for producing polyester using the catalyst, wherein the catalyst for preparing polyester is a hydrolyzate obtained by hydrolyzing titanium halides. Obtained by dehydration drying, it becomes a solid titanium compound whose molar ratio (OH / Ti) of hydroxyl group (OH) and titanium (Ti) is more than 0.09 and less than 4. In addition, the present invention is to provide a method for obtaining a polyester having a small increase in acetaldehyde content during molding, and this method is obtained by using a titanium compound catalyst, and the concentration of phosphorus atom in terms of It is a method of contacting with phosphate ester aqueous solution etc. which are 10 ppm or more. Another object of the present invention is to provide a polyester having excellent transparency and color characteristics and a molded article made of a hollow molded article, a film or a sheet, a fiber, and the like, wherein the polyester is a polycondensation catalyst component of a solid titanium compound and magnesium A polyester obtained by polycondensing an aromatic dicarboxylic acid or its ester formable derivative with an aliphatic diol or its ester formable derivative in the presence of a catalyst for producing a polyester as a cocatalyst component, wherein the titanium content is 1 to 100 ppm , Magnesium content of 1 to 200ppm, the weight ratio (Mg / Ti) of titanium and magnesium contained in the polyester is 0.01 or more polyester. |