Unsymmetrical polyurethane polyol prepolymers are disclosed for use in the
formation of coating compositions. The prepolymers are prepared as a
reaction product of a diisocyanate with a short chain aliphatic diol and
a long chain polymeric diol. The prepolymers are intended as the first
component for reaction with a second component polyisocyanate in a
two-component coating composition. The coating compositions exhibit
excellent abrasion resistance and weatherability, and are particularly
useful as coatings for polymeric window transparencies.