. . "ng large amounts of plasticizer may be obtained by reaction of an organic polyisocyanate and a polyol, e.g. a polyester or polyether containing reactive terminal groups, such as hydroxyl, preferably a polyester, and a diamine trihydroxy compound having the formula: H (O-alkylene) (alkyleno-O yH wherein n is a whole number from 1 to 10, preferably 2 or 3, alkylene means a divalent saturated aliphat" . .