Copolyetherester elastomer with cycloaliphatic hard segments

Claim 1

An improved thermoplastic, segmented, linear copolyetherester elastomer which consists essentially of a multiplicity of recurring long-chain units and short-chain ether-ester units connected head-to-tail through ester linkages, the long-chain units amounting to at least 50 percent by weight of the elastomer and being represented by the structural formula ##STR5## short-chain ester units amounting to 10 to 50 percent by weight of the elastomer and being represented by the structural formula ##STR6## in which R is a divalent radical which remains after removal of carboxyl groups from a dicarboxylic acid, G is a divalent radical which remains after removal of hydroxyl groups from a poly(alkylene oxide) glycol having a carbon-to-oxygen ratio in the range of 2.0 to 4.3 and a molecular weight in the range of 1,000 to 5,000, and D is a divalent radical remaining after removal of terminal hydroxyl groups from a diol, wherein the improvement comprises the R and D radicals being the same or different, R and D each being a divalent cycloaliphatic radical having a structural formula selected from the group consisting of ##STR7## R and D each being at least 40% trans isomer and either the R or D radical being at least 70% trans isomer.