Preparation of Waterborne Polyurethane Coating for Aluminum Alloy

A waterborne polyurethane coating for Al alloy was prepared by synthesis of polyurethane emulsion and using zinc orthophosphate organically modified by aluminum and molybdenum as anti-corrosive pigment. The effects of anti-corrosive pigment, content of tung oil acid monoylyceride (EAM), ratio of pigment to binder and auxiliaries on properties of the coating were discussed. The results indicate that the anti-corrosion properties of the waterborne polyurethane coating were good, the adhension between the coating and Al alloy was high, when the content of EAM was 20%, the anti-corrosive pigment was zinc orthophosphate organically modified by aluminum, and the mass ratio of pigment to binder was 1.2.