Patent ID: 7705109

Claim:
Process for the preparation of a block copolyetherester elastomer comprising polyester blocks and poly(alkylene oxide) polyol blocks, wherein at least one aromatic dicarboxylic acid or an ester-forming derivative thereof, at least one alkylene diol, and a poly(alkylene oxide) polyol, comprising a poly(propylene oxide), end capped with ethylene oxide, are esterified, and wherein the poly(alkylene oxide) polyol has an ethylene oxide content of between 22 and 90% by weight, relative to the total weight of the poly(alkylene oxide) polyol, the poly(alkylene oxide) polyol has an unsaturation content, being the total content of vinyl and allyl groups, of less than 25 meq per kg poly(alkylene oxide) polyol, and the poly(alkylene oxide) polyol has an Mn of between 2500 and 5000 g/mol.