Abstract: A modified polyepoxide is disclosed which cures with an amine-functional curing agent at room temperature to form coatings having better flexibility and resistance to Skydrol hydraulic fluid. This modified polyepoxide is the reaction product of a diurethane diisocyanate with a resinous polyepoxide having a molecular weight of from about 500 to about 1000 and a 1,2-epoxy equivalency of from about 1.5 to about 2.0. The diurethane diisocyanate is reacted with the resinous polyepoxide in an amount of from about 1.5 moles to about 16 moles per 100 moles of the polyepoxide. The diurethane diisocyanate is itself the reaction product of a dicarbinol-terminated polydimethyl polysiloxane having a molecular weight of from about 1000 to about 4000 with substantially a 2:1 stoichiometric excess of an organic diisocyanate.