Low-Melt Polyamic Acid Based Powder Coatings

Abstract

The present invention is directed to a method for powder coating a metal substrate using a low-melt polyamic acid (PAA) polymer that readily imidizes to polyimides. These low-melt PAAs have been shown to be useful in resins applied as powder coatings to metal surfaces. The resin includes an end-capping material capable of providing crosslinking functionality to at least one end of the low-melt PAA polymer. The end-capping material functions dually as a polymerization chain terminator and crosslinking agent, thus producing resins that have molecular weights low enough to flow well and form good cured films applicable for use in powder coating.