Study On The Preparation Of Waterborne Anti-corrosion Coatings

Waterborne coatings have lower VOC than traditional solvent-based coatings, arguably it will be better for the environment if waterborne coatings can displace solvent-based coatings. In this paper, two kinds of waterborne coatings, waterborne epoxy resin coating and waterborne amino-alkyd baking paint, were prepared.(1) In this paper, a kind of waterborne epoxy resin emulsion was prepared by ultrasonic. The influence factors on stability of waterborne epoxy resin emulsion such as emulsification temperature, HLB value and emulsifiers content were investigated. Rheological properties of waterborne epoxy resin emulsion were studied before phase-inversion as well as after it. The optimal results are as fellows:HLB is17, emulsification temperature is70℃, and emulsifiers content is7%-8%of epoxy resin mass. It shows that the particle size of emulsion through ultrasonic emulsification is smaller than that without ultrasonic emulsification, and the particle size distribution is also narrower than without ultrasonic emulsification.(2) A kind of waterborne epoxy coating was prepared which using waterborne epoxy resin emulsion as binder and red Fe2O3as pigment as well as CaCO3as fillings. The optimal formula was chosen through four factors quadratic regression orthogonal experiment and SPSS. The film has good anti-corrosive property, its hardness is3H and curing time is8h.(3) A kind of waterborne alkyd resin was prepared through using waste cooking oil as fatty acid, and the ratio of reactants was determined through the theoretical formula calculation and experimental confirmation. Effect of catalyst content on reaction time was studied and effects of reaction temperature on reaction time as well as molecular weight and molecular weight distribution were studied. Results show that:catalyst content is0.75g/50g, reaction temperature is230℃. The waterborne alkyd was characterized by FTIR, GPC and DSC respectively.(4) A kind of amino-alkyd baking paint was prepared by waterborne alkyd resin and high methyl ether amino resin. All of acid catalyst content, baking temperature, and ratio between amino resin and waterborne alkyd resin were determined by single factor experiment. Results are as fellows:acid catalyst content is6%, baking temperature is120℃, atio between amino resin and waterborne alkyd resin is1:3.Effects of leveling agent and defoamer on film were discussed. Properties of film were characterized by TG, SEM, electrochemical impedance and corrosion resistant. Curing time is30min, film hardness is2H, and adhesion can reach level1.(5) A kind of BPA、BA and MA modified waterborne air dry alkyd resin was prepared, which used linseed oil as fatty acid. Both of the relationship between reaction time and acid value as well as the relationship between water content and diluting peak were discussed. The waterborne alkyd was characterized by FTIR. Effect of drier content on curing time was studied, and the better drier content is0.8g. Properties of film were studied, and its curing time is16h at room temperature, film hardness is H, and adhesion can reach level1.