CROSS-LINKABLE PULVERULENT COATING COMPOSITIONS

摘要

A pulverulent coating composition adapted to be applied to a substrate by spraying as a powder is prepared by a process which comprises reacting an organic polyisocyanate containing a uretdione group with an organic compound containing groups which contain reactive hydrogen atoms determinable by the Zerewitinoff method wherein the functionality of the reactants and the proportions thereof are chosen to provide an average functionality between about 2.05 and 10, the ratio of reactive hydrogen groups to -NCO groups is between about 1.07 to 1 and about 2.5 to 1 and the amount of polyisocyanate containing uretdione groups is sufficient to provide from about 0.6 percent to about 25 percent by weight uretdione groups.