Patent ID: 9624342
Date: 2017-04-18
CPC Classifications: C08G

Claim:
1. A process for preparing high molecular weight polyester syrups, which process comprises: a) providing or forming an ester oligomer in a first esterification step and substantially without ethylene glycol or propylene glycol, wherein the hydroxyl:acid or hydroxyl:ester ratio is from about 0.98:1 to about 1.1:1; b) converting the oligomer to a polyester polymer by stirring at pressure of about 34 kPa to about 100 kPa gauge and elevated temperature a reaction mixture containing the oligomer and 5 wt.% or more of a nonreactive carrier capable of forming an azeotrope with water and having a boiling point greater than that of xylenes; c) allowing the pressure to rise to about 100 kPa; and d) removing water from the reaction mixture via azeotropic reflux to provide a syrup comprising a medium high molecular weight polyester polymer in the nonreactive carrier.