| abstract |
A process of preparing poly(trimethylene terephthalate) containing less than 2.0 mole % of DPG 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 10-100ppm (as titanium metal) of an organic titanate catalyst, by weight of the poly(trimethylene terephthalate), and (c) polymerizing the bis(3-hydroxypropyl)terephthalate monomer to obtain the poly(trimethylene terephthalate); and poly(trimethylene terephthalate) produced by the process. |