Catalyst for polyester polycondensation and method for producing polyester resin using the same

Abstract

The invention provides: a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost; a polyester resin obtained with the catalyst; and a molded article. These are: a polymerization catalyst for polyester production containing titanium atoms, alkaline earth metal atoms and phosphorus atoms and having a specific constitution; a polyester resin obtained with the catalyst; and a molded article.

1 - 9 . (canceled) 
     
     
         10 . A liquid polycondensation catalyst for polyester production, which is obtained by mixing an alcohol, an alkaline earth metal compound and an acid phosphoric ester compound to obtain a liquid mixture, and further mixing a titanium compound with said liquid mixture. 
     
     
         11 . The polycondensation catalyst for polyester production of  claim 10 , wherein the alcohol is an alkylene glycol. 
     
     
         12 . The polycondensation catalyst for polyester production of  claim 10 , wherein the titanium content in terms of titanium atom content is in the range of 0.01-2% by weight, and the molar ratio of the alkaline earth metal (M) to phosphorus and the molar ratio of titanium to phosphorus satisfy expressions (1) and (2), respectively:
   0.1 ≦M /P≦3  (1)
     0.1≦Ti/P≦5  (2)
   
       wherein (Ti, Mg, and P each represent the contents (on mole basis) of titanium, the alkaline earth metal, and phosphorus in the polycondensation catalyst for polyester production. 
     
     
         13 . The polycondensation catalyst for polyester production of  claim 10 , which contains water in an amount of 0.01-10% by weight. 
     
     
         14 . The polycondensation catalyst for polyester production of  claim 10 , wherein the alkaline earth metal compound is a magnesium compound. 
     
     
         15 . The polycondensation catalyst for polyester production of  claim 14 , wherein the magnesium compound is the magnesium salt of an organic acid, or a hydrate of the salt. 
     
     
         16 . The polycondensation catalyst for polyester production of  claim 10 , wherein the titanium compound is a tetraalkyl titanate. 
     
     
         17 - 20 . (canceled)