Polyester of terephthalic acid and oligo alkylene oxides

Polyester polyol with a concentration of ether groups in the range from 9.0 mol / kg of polyester polyol and 16 mol / kg of polyester polyol produced from a mixture comprising (A) terephthalic acid, (A) (B) oligoethylene of formula H- (OCH2CH2) n-OH with a number average number of oxyethylene groups n in the range between 3.0 and 9.0, and (C) at least one aliphatic dicarboxylic acid selected from the group consisting of succinic acid, glutaric, adipic acid, sebacic acid, suberic acid, azelaic acid, decane dicarboxylic acid, dodecane dicarboxylic acid and omega-hydroxycaproic acid.