A crosslinking agent in the water or aqueous reactant is polyol such as pentaerythritol having a reactive funccrucial when the isocyanate capped reaction product tionality equal to 4 is reacted with a large molar excess has a functionality of only about 2 and only optional of a diisocyanate to form an isocyanate capped polywhen the functionality thereof is greater than 2. urethane intermediate pro