Unsaturated polyesters

Abstract

Unsaturated linear polymers have repeating units of a reaction product of a first monomer, a second monomer, a third monomer and optionally a fourth monomer. The linear polymers have a glass transition temperature ranging from about 52.degree. C. to about 61.degree. C. The first monomer should have a weight average molecular weight less than 200. The second monomer may be a dicarboxylic acid or diester which is different than the third monomer. A concentration of second residues of the polymer, derived from the second monomer, ranges from about 3 wt. % to about 15 wt. %, based on the total weight of the polymer. The third monomer is an aromatic dicarboxylic acid or an ester thereof. In the polymer, a concentration of third residues, derived from the third monomer, ranges from about 40 wt. % to about 55 wt. %, based on the total weight of the polymer. The fourth monomer is a diol having a higher molecular weight than the first monomer. In a process for preparing the inventive polymer, the first, second, third monomer (and optionally a fourth monomer) and/or a catalyst undergo transesterification to form the unsaturated, linear polymer.

Dependencies are inferred from the claim text.