Process for the preparation of polyester polyols and/or polyester-polyether polyols

摘要

Polyester polyols and/or polyester-polyether polyols are prepared by reacting polyols preferably di- to hexafunctional polyether polyols with hydroxyl numbers of 30 to 200 with at least one carboxylic anhydride, preferably glutaric anhydride, resulting in a carboxylic acid half ester which is subsequently oxyalkylated with at least one alkylene oxide, preferably ethylene oxide in the presence of at least 1 thiodialkylene glycol, preferably thiodiethylene and/or thiodipropylene glycol.