Process for workpiece coating with a conductive primer

Abstract

Abstract The present invention is directed to improved conductive primer composition and methods. In the improved methods aspect of the present invention, a non-conductive polymeric component is precoated with a primer to render it electroconductive in preparation for electrocoating. Next, the primed polymeric component is assembled with a conductive matallic component to form a multi-material workpiece. Finally, the formed workpiece is submerged in an electrocoat bath for simultaneously electrocoating both the primed polymeric component and the conductive metallic component. In some preferred embodiments, the workpiece may be an automobile chassis. In the improved electroconductive primer compositions aspect of the present invention, such compositions comprise a dispersion of approximately 70% to 90% of a polymeric resinous binder which will cure to form a film, approximately 10% to 30% of a conductive carbon pigment, approximately 0.2 to 0.45 of an electron transmitting surfactant to provide in the cured film conductive pathways for electrons between the conductive pigment particles, and approximately 20% to 30% of a finely ground metal in alternative preferred embodiments, and a sufficient volume of solvents to provide a flowable viscosity to the primer. Such primer may be formed from a wide variety of different resins.

Inventors

• 👤 Salvador R. Lo

Bibliographic Details