Synthesis of Waterborne Anticorrosive Coatings Based on The Incorporation of Phosphate Groups to Polyurethane-Acrylate Hybrids

In this work, solvent-free waterborne polyurethane-poly(meth)acrylate hybrid dispersions that can be used to formulate anticorrosive paints are synthesized. To achieve the anticorrosive protection, a phosphate containing polymerizable surfactant, Sipomer PAM 200 is incorporated to the hybrids. The presence of phosphate groups can produce an iron phosphate passivation layer to provide coatings with anticorrosive properties. These properties are tested in both mild and harsh corrosive environments. It is observed that when the films are dried at 60% relative humidity conditions, very poor anticorrosive protection is achieved because no phosphatization is obtained, but increasing the humidity to 85% during the drying step allows the formation of the passivation layer providing good anticorrosive properties.