| abstract |
The present invention relates to a process for the preparation of polyricinoleic acid ester polyols having primary hydroxyl end groups. It furthermore relates to polyricinoleic acid ester polyols obtainable according to the invention and polyurethane polymers prepared using these polyols. The process comprises the steps: a) polycondensation of ricinoleic acid until a hydroxyl number of >0 mg of KOH/g to <60 mg of KOH/g is reached; and b) reaction of the product obtained in step a) or of a secondary product of the product obtained in step a) comprising carboxyl groups with an epoxide of the general formula (I), wherein R1 represents hydrogen, an alkyl radical or an aryl radical, with the proviso that >80% by weight to <100% by weight, based on the total amount of the epoxide (I) employed, is ethylene oxide and the reaction is carried out in the presence of an amine as the catalyst. |