Phase separating polyurethane prepolymers and elastomers prepared by reacting a polyol having a molecular weight of 600-3500 and isocyanate and a low molecular weight chain extender in which the ratios of reactants have a limited range

摘要

Reactive, 100 percent solids, segmented, phase-separating polyurethane prepolymers are provided, being the reaction products of: (i) a polyol (A) having a number average molecular weight of from about 600 to about 3500 and having a functionality of at least 2; (ii) an isocyanate (B) having a functionality of at least 2; and (iii) a low molecular weight chain extender (C) having a molecular weight in a range lower than about 500 and having a functionality of at least 2, characterized in that the above reactants are employed in such proportions as to satisfy the following equations: IMAGE (a) EqOH/=EqCE (b) EqCEO, (c) wherein EqNCO is the equivalents of the isocyanate species employed, and EqOH and EqCE denote the equivalents, respectively, of the polyol and chain extender. This invention provides the aforesaid novel prepolymers, the processing made possible by the prepolymers, the polyurethane elastomers resulting from the prepolymers and the products made from those elastomers.