Abstract: In a process for preparing polyesters by mixing at least one non-vicinal aliphatic diol, e.g., 1,4-butanediol or its ester-forming equivalents with at least one dicarboxylic acid, e.g., terephthalic acid or its ester-forming equivalents in the presence of a tetraalkyl titanate catalyst, and adding to the mixture a tetraalkyl zirconate catalyst in amounts such that the ratio of titanium atoms to zirconium atoms is 1.3:1 to 9:1, preferably 1.9:1 to 4.6:1.

Abstract: An elastomeric copolyester having a multiplicity of recurring intralinear long chain and short chain ester units connected through ester linkages wherein:(A) about 75-96 weight percent of said short chain ester units are represented by the following formula ##STR1## (B) about 4-25 weight percent of said long chain ester units are selected from units represented by the following formulas ##STR2## wherein G is a divalent radical remaining after removal of hydroxyl groups from a poly(alkylene oxide) glycol having a number average molecular weight of about 400-1100 and a carbon-to-oxygen atomic ratio of 3-4,R is a divalent radical remaining after removal of carboxyl groups from dicarboxylic acids which are provided as a mixture comprising:(1) about 50-90 weight percent terephthalic acid,(2) about 5-25 weight percent of at least one hexacarbocyclic dicarboxylic acid in which the carboxyl groups are attached to the hexacarbocyclic nucleus in a 1,2- or 1,3-relationship(3) about 5-25 weight percent of at least one al