METHOD FOR PRODUCING POLYESTER POLYOLS HAVING SECONDARY OH TERMINAL GROUPS

摘要

The invention relates to a method for producing polyester polyols having secondary hydroxyl terminal groups, comprising the step of reacting polyester comprising carboxyl terminal groups with an epoxide of the general formula (1), where R1 stands for an alkyl radical or an aryl radical, and the reaction is performed in the presence of a catalyst comprising at least one nitrogen atom per molecule. The method is characterized in that the polyester comprising carboxyl terminal groups has an acid number of = 25 mg KOH/g to = 400 mg KOH/g and a hydroxyl number of = 5 mg KOH/g, and that the polyester comprising carboxyl terminal groups is produced in that = 1.03 mol to = 1.90 mol of carboxyl groups or carboxyl group equivalents of an acid component are added per mol of hydroxyl groups of an alcohol. The polyester polyols comprising secondary hydroxyl terminal groups thus obtained can be used for producing polyurethane polymers.