TWO COAT WELDABLE PRIMER FOR STEEL

摘要

A mar resistant, weldable zinc-coated metal substrate capable of sustaining the life of a copper-tipped electrode used in welding the substrate through a minimum of 2000 welds is achieved by applying a weldable primer coating composition to the metal, heating the primer composition to provide the desired dry coating, applying a protective coating composition over the primer coating in an amount sufficient to provide from 538 to 4306 mg/m<2> of a dry film, and heating the protective coating composition to produce the dry film. Without the resin-based protective coating, the weldable primer is easily marred. The resin-based protective coating, which is generally from 0.25 to 3.25 mu m thick, improves the mar resistance of the primer and enhances the corrosion resistance of the zinc-coated steel without interfering with the weldability of the primer.