Abstract: The reaction product of an adduct of an ethylenically unsaturated monohydric alcohol, such as 2-hydroxyethyl acrylate, with an organic diisocyanate in which one of the two isocyanate groups is more strongly reactive than the other, such as isophorone diisocyanate, is reacted with a phenoxy resin in solvent solution. The alcohol is used in a molar excess of at least about 3% up to 30% to insure the absence of any significant proportion of unreacted diisocyanate. The phenoxy resin which is reacted with is a high molecular weight hydroxy functional polyether having a number average molecular weight above 10,000 and an hydroxy functionality in the range of from about 20 to about 300. The adduct is used in an amount to introduce about 1.5 to about 20 ethylenically unsaturated groups per molecule of the polyether, and the reaction is continued to substantially eliminate unreacted isocyanate functionality.