Patent ID: 6441129
Filing Date: 2002-08-27
Classification: C08G

Abstract:
A process for producing poly(trimethylene terephthalate) and achieving an increased solid state polymerization rate wherein 1,3-propanediol, and optionally other diols, and an aromatic acid or diester thereof are esterified or transesterified, the esterification or transesterification product is polycondensed to produce a prepolymer, and the prepolymer is subjected to continuous solid state polymerization at a temperature of 210 to 225Â° C. and then at a temperature above the normal melting point of the prepolymer for 1 to 20 hours to produce a polymer with an intrinsic viscosity of 1.3 d/g or greater using a prepolymer with an intrinsic viscosity from 0.50 to 0.70 dl/g.