Patent ID: 7250484
Filing Date: 2007-07-31
Classification: C08G

Abstract:
1. A method for increasing the rate of solid state polymerization for polyethylene terephthalate (PET), which comprises: (i) directly esterifying or transesterifying, then copolymerizing in the melt, at temperatures between 250° C. and 310° C., with the other PET precursor materials at least one monomeric unit selected from the group consisting of diols, diacids and dimethyl esters that contain at least one pendant side group selected from the group consisting of tertiary butyl, hexyl, pentyl, butyl, propyl, ethyl, methyl, nitrosyl (NO 2 ) and sulfonyl (SO 2 ) groups to form a polymer feedstock; and (ii) solid state polymerizing the polymer feedstock under heated nitrogen and/or air at a temperature between 160° C. and 230° C.