Research On Preparation And Properties Of Baking Waterborne Paint For Automobile Parts

In this paper,water-based baking coatings are the research object,combined with the protection requirements of auto parts and related standards,11 water-based polyester resins,11 water-based acrylic resins and 3 water-based amino resins are selected for performance evaluation,and the applicable water-based resins are selected.Through the design of coating schemes,screening of pigments,fillers and additives,formulation design and optimization,and evaluation of coating performance,a coating system supporting water-based polyester amino intermediate paint for automotive parts and water-based acrylic amino topcoat are developed.The preparation and performance research of waterborne polyester amino intermediate paint are carried out.By screening water-based polyester resin and water-based amino resin and optimizing the ratio,selecting suitable pigments,fillers and additives,a water-based polyester amino baking coating with good leveling properties is prepared.The results show that:when the mass ratio of A03 waterborne unsaturated polyester resin to methyl etherified melamine formaldehyde resin is 5:1,the DSC exothermic peak of the prepared varnish is about 135?,and the varnish is cured at 135?140? for 25?30min,the hardness of the layer can reach 3H and the heat resistance and medium resistance are excellent;the type and amount of pigments and fillers are optimized through orthogonal experiments.When the amount of zinc phosphate is 3wt%,the amount of aluminum tripolyphosphate is 10wt%,and the amount of talc is 4wt%,the prepared The coating has good mechanical properties,the water-resistant 240h coating has no damage,and has excellent resistance to low-concentration H2SO4,NaOH and other media.The preparation and performance study of water-based acrylic amino topcoat are carried out.By screening the water-based acrylic resin and optimizing its ratio with the water-based amino resin,using rutile titanium dioxide and a variety of additives,a water-based acrylic amino baking coating with good weather resistance is prepared.The results show that when the mass ratio of B08 water-based acrylic resin to methyl etherified melamine formaldehyde resin is 4:1,the DSC exothermic peak of the mixed resin is about 135?;the color paint with a titanium dioxide content of 20wt%is subjected to 130?135? After curing for 25-30min,the coating has good mechanical properties and medium resistance.The color difference?E*<1.0 after 500h UV aging.The developed water-based polyester amino intermediate paint has good compatibility with water-based acrylic amino topcoat,and the interlayer adhesion is?4MPa;it is painted on the surface of the electrophoretic primer to form a water-based anti-corrosion and weather-resistant coating system for auto parts that is resistant to media and weather Excellent performance.