The invention relates to new polyamines, preferably containing polyether segments, a process for their preparation and their use as starting components for the production of polyurethane resins. The process involves producing ketimines, aldimines or enamines containing hydroxyl groups by reacting a hydroxyl amine with an aldehyde or ketone and removing the water by product. The ketimine, aldimine, or enamine is then reacted with an NCO prepolymer wherein the hydroxyl group of the material reacts with the isocyanate group without disturbing the blocked amine. This polyaddition product is then hydrolyzed to unblock the high molecular weight polyamine.