MANUFACTURE OF OLIGOESTER CONTAINING HYDROXY GROUP AND USE

Oligoesters having hydroxyl groups and an OH number of from 200 to 600 mg KOH/g are made by reacting a cyclic dicarboxylic acid anhydride in which no halogen is present with a polyfunctional alcohol or dialkanolamine in a molar ratio of from 1:0.5 to 1:1.5 at a temperature of from 50 DEG to 150 DEG C. to form the corresponding dicarboxylic acid semiester and/or semiamide. This semiester and/or semiamide is then alkoxylated with ethylene oxide and/or propylene oxide in the presence of a catalyst at 80 DEG to 150 DEG C. The equivalent ratio of acid groups to alkylene oxide groups is from 1:0.8 to 1:1.7. The catalysts are reaction products of alkoxides with at least 3 C-atoms with ammonia, piperidine, piperazine and/or C2-C6 aliphatic, polyamines, preferably diamines in which all of the NH-functional groups have been alkoxylated. The resultant oligoester may then be reacted with a polyisocyanate optionally in the presence of known additives, such as blowing agents and catalysts.