Patent ID: 8063122
Filing Date: 2011-11-22
Classification: C08K

Abstract:
1. In a method for the manufacture of a polyester composition comprising the steps of: A) producing a dicarboxylic acid dialkylester by reaction of an alkanediol with a dicarboxy acid or a dicarboxy acid ester; B) pre-polycondensation of said dicarboxylic acid dialkylester to form pre-polycondensates; C) melt polycondensation of said pre-polycondensates to form polyester; the improvement comprising including a low-turbidity solution during said melt polycondensation, said solution comprising at least one alkali- and/or alkaline-earth metal salt, and at least one composition comprising at least one phosphonic acid ester of the Formula (I) wherein each R independently is a group with 1 to 60 carbon atoms and R′ is a binding group with 1 to 20 carbon atoms, said low-turbidity solution being prepared by (i) dissolving said at least one alkali and/or alkaline-earth metal salt in water, (ii) then adding thereto at least one organic solvent, and (iii) then adding thereto a composition comprising at least one phosphonic acid ester of the Formula (I) and an organic solvent, wherein said low-turbidity solution exhibits a turbidity level equal to or less than 8 NTU and wherein the amount of at least one alkali- or alkaline-earth metal in said alkali or alkaline earth metal salt lies between 10 and 500 ppm with respect to the weight of the dicarboxylic acid dialkylester.