| The cathodic electrodeposition coating is widely used in the metal surface for corrosion resistant and decorative. One of the most commonly used matrix resin is epoxy resins, which owns good chemical resistance, inoxidability and other properties. But it is brittleness and inferiors weather resistance. But the epoxy resin brittle large and poor weather resistance, so curing agent has to be added, which was most commonly used a high temperature and took a long time to accomplish the curing. The main content of this paper is about using the polyethene glycol and the acrylic esters to improve the shortcomings of the epoxy resin, and preparing the low-temperature re-opened the curing agent. Then I researched the process of cathodic electrodeposition coating using the being prepared cathodic electrodeposition coating with favourable inoxidability and environmental protection performance.The experiment proved that the reaction of the graft and expansion took place, and that the thermal stability had been a marked improvement by FT-IR and TG to characterize.I Studied the impact of various factors on the cathodic electrodeposition coating’s emulsion and the film properties, which have the type and amount of polyethene glycol, acrylaic esters monomers and organic amines, and the reaction temperature and time of reaction. The emution is prepared by the optimized experimental condition which is the total mass of resin’s13～14%PEG1000, reaction in4h at the chain extention temperature90℃,ω(AIBN) with0.36%and ω(BPO) with0.72%, reaction in2h at95℃acrylate monomer dropping into the reactants and then being heated to105℃for2h, the pH value of the emulsion stability (6.0±0.3).Experiment study that the trimer performance is impacted by the proportion of TDI and IPDI, amount of catalyst, and reaction conditions. And experiment optimized the reaction conditions, which was the different modificated method and closed conditions of the prepared curing agents and film properties. Experiment to get the optimum conditions for curing agent as follows:n(TDI):n(IPDI) was1:2, the amount of catalyst was0.6%, reaction temperature about80℃, the amount of solvent for3%, selecting the PEG400dropping the reactants at60℃in0.5h, and heating up to85℃in1.5h, using the butanone oxime reaction in2h at80℃. Then the being prepared of curing agent’s emution was light yellow transparent, excellent storage stability and starting to re-open for making the film crosslinking. So that the paint film smooth level off, corrosion resistance and other properties are good as well.The paper simply discusses the process of cathodic electrodeposition coating. From the micro perspective, the paper discussed the electrochemical cathodic electrophoretic painting principle, and expounds the metal surface pretreatment and electrophoresis process parameters of control of the performance of the film and its significance. The research is mainly about electrophoretic parameters on the bath and the influence of the film performance, electrophoresis parameters including electrophoresis voltage, bath temperature, bath solid content, electric conductivity and electrophoresis post-treatment. Through the optimized coating process, the film got smooth level off, to25μm, thickness of adhesion to0level, impact resistance strength for50Kg·cm, etc. |
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