Integral epoxy resin–silane primer system for hot-dip galvanized steel
Abstract-The corrosion resistance of an environmentally-friendly integral 2-in-1 resin-silane primer coating system on hot-dip galvanized steel was investigated. The coating formulation exhibiting the best corrosion resistance was found to be a mixture of hydrolyzed and non-hydrolyzed silanes incorporated into a commercial epoxy resin-curing agent system. Salt-spray testing indicated that the coating exhibited good corrosion resistance. Impedance values were significantly higher for the integral resin-silane coating, as compared with the commercial resin alone. Impedance values of the integral primer coatings increased with time, as secondary curing reactions imparted by the presence of the non-hydrolyzed silane proceeded. Due to the presence of the hydrolyzed silanes, the investigated coatings exhibited good adhesion to both the hot-dipped galvanized steel substrate, as well as to the polyester topcoat.