Patent ID: 6472500
Filing Date: 2002-10-29
Classification: C08G

Abstract:
A process for the prepatation of linear poly(alkylene terephthalate) resins, comprising:reacting an aromatic dicarboxylic acid with an excess of an alkane diol wherein the ratio of alkane diol to aromatic dicarboxylic acid is from about 1.2:1 to about 4:1 under conditions effective to reach the clearing point of the reaction; pre-polymerizing the cleared reaction mixture under conditions effective to produce an oligomeric mixture having an intrinsic viscosity measured in 60/40 phenol/1, 1, 2, 2,tetrachloroethane at 25Â° C. of less than or equal to about 0.70 dl/g and a carboxylic acid end group number of less than or equal to about 100 meq/kg; and polycondensing the oligomeric mixture under vacuum and temperature conditions effective to produce a linear poly (alkylene terephthalate) resin having an intrinsic viscosity measured in a solution of 60/40 phenol/1, 1, 2, 2-tetrachloroethane at 25Â° C. of greater than about 0.80 dl/g and a carboxylic acid end group number of about 10 to about 40 meq/kg.