Patent Number: 6,441,129

Title: High temperature solid state polymerization of poly (trimethylene terephthalate)

Abstract: The present invention is a process for producing poly(trimethylene terephthalate) (PTT) at an increased solid state polymerization rate, wherein 1,3-propane diol and an aromatic acid or a dialkyl ester thereof are esterified or transesterified, the esterification or transesterification product is polycondensed, and the polycondensation product is pelletized and then subjected to continuous solid state polymerization at a temperature of 200 to 225.degree. C., preferably 210 to 225.degree. C. In one embodiment of the present invention, the temperature range is 200 to 220.degree. C., and the pellet size of the polymer to be solid state polymerized is from 1.0 to 1.5 g/100. In another embodiment of the present invention, the solid state polymerization is carried out at 210 to 225.degree. C. for from 1 to 20 hours and then the temperature is increased to above the initial melting point of the polymer to produce a PTT polymer with an intrinsic viscosity of 1.3 dl/g or greater.

Inventors: Duh; Ben (Tallmadge, OH), Corey; Ann Marie (Akron, OH)

Assignee: Shell Oil Company

International Classification: C08G 63/00 (20060101); C08G 63/80 (20060101); C08G 63/183 (20060101); C08F 006/00 ()

Expiration Date: 08/27/2010