POLYURETHANE SEALING MATERIAL BASED ON CASTOR OIL, ITS MANUFACTURE AND FILM SEALING METHOD

摘要

Potting media based on polyurethanes produced with castor oil, a process for their preparation as well as their use. To at least one of the ingredients of the potting medium is added a dialkyltin compound in an amount resulting in a content of from about 5 to 50 ppm, calculated as elementary tin, of the dialkyltin compound. A diisocyanate based on a carbon ring compound in stoichiometric excess is reacted with a mixture of castor oil and trimethylolpropane to a prepolymer having NCO-groups. Then the prepolymer is mixed with castor oil or a mixture of castor oil and trimethylolpropane for crosslinking. Preferred diisocyanates are aromatic diisocyanates having up to about 30 carbon atoms. The potting media exhibit a favorable course of the viscosity, wet excellently and distribute very rapidly and are particularly suited for the embedding of membranes.