Preparation and properties of a primer-topcoat composite water-based acrylic amino baking paint
[Introduction] The comprehensive performance of the primer-topcoat composite water-based acrylic amino baking paint needs to be improved. [Method] A primer-topcoat composite water-based acrylic amino baking paint with excellent comprehensive performance was prepared by optimizing the combination of pigments and fillers for the primer through orthogonal test, using the water-based hydroxyl acrylic dispersion as the binder with amino and isocyanate curing agents. The properties of the films prepared with the optimized composition of primer and four orthogonal testing groups with the relatively low corrosion rates were compared based on the physicochemical property testing and electrochemical characterization. The effects of the binder content and pigment-to-binder ratio on the properties of the primer were discussed. The baking process of the primer was also improved. [Result] The film of the primer prepared with modified precipitated barium sulfate, mica, aluminum triphosphate, strontium aluminum polyphosphate hydrate, and black paste at the optimal mass ratio of 8:2:3:4:5 had the most positive corrosion potential and the lowest corrosion current density in 5％ NaCl solution, and endured the neutral salt spray test up to 480 hours. The composite coating composed of a waterborne acrylic amino-polyurethane topcoat with a thickness of ca.25 μm and the primer with a similar thickness prepared with 45％ of binder at a pigment-to-binder ratio of 0.8 by baking for 10 min endured acid immersion, alkali immersion, and neutral salt spray test for 360 hours, 360 hours, and at least 2000 hours, respectively. [Conclusion] The baking paint can fully meet the performance requirements of water-based anticorrosion coatings for steel structures.
water-based acrylic amino baking paintpigment and fillerorthogonal testanticorrosionelectrochemistry
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