Patent ID: 6335421
Filing Date: 2002-01-01
Classification: C08G

Abstract:
A process of preparing poly(trimethylene terephthalate) comprising:(a) providing a molar amount of 1,3-propanediol:C1 to C4 dialkyl ester of terephthalic acid of 1.2:1 to 1.9: 1; (b) reacting the 1,3-propanediol with the C1 to C4 dialkyl ester of terephthalic acid to form bis(3-hydroxypropyl)terephthalate monomer in the presence of 10-100 ppm (as titanium metal), by weight of the poly(trimethylene terephthalate), of tetraisopropyl titanate catalyst; and (c) polymerizing the bis(3-hydroxypropyl)terephthalate monomer in the presence of 10-100 ppm (as titanium metal), by weight of the poly(trimethylene terephthalate), of tetraisopropyl titanate catalyst to obtain poly(trimethylene terephthalate) having an IV of 0.7 to 2.0 dl/g and containing less than 2.0 mole % of DPG.