| The paper focused on the preparation of a kind of environmental waterborne anti-corrosion coating based on the waterborne styrene-acrylate emulsion with excellent mechanical properties, excellent salt spray resistance and low curing temperature.The main experimental results were as follows:1. The low temperature drying styrene-acrylate emulsion was synthesized by the styrene polymerization monomers, such as MMA, BA, EHA, MAA, St and so on. It was characterized by TEM, SEM and particle size analysing. The glass transition temperature of the emulsion was determined by the formula design and the evaluation of polymerization process. The factors that affect the emulsion polymerization and the properties of its film were investigated. The result showed that when the glass transition temperature of the emulsion was designed in35～45℃, the monomer ratio of hard:soft was2:1, the emulsifier ratio of anion:nonionic was2:1, the emulsifier dosage was2.5%, the dosage of ammonium persulfate was0.6%and sodium sulfite solution(10%mass) was0.5～1.Og. The polymerization temperature was80℃.The emulsion appearance was best, the gel rate was low, the film forming ability was good, the monomer conversion rate was high and the emulsion particle size distribution was small and uniform.2. The functional hydroxy-acrylate monomer was prepared by the reaction of GMA and concentrated phosphoric acid.The acid test was used for determining the reaction time and the infrared spectroscopy was used to characterize the structure of functional hydroxyl phosphate monomer. The GMA and the concentrated phosphoric acid were added dropwise following the molar ratio was2to1in an ice-water bath at0℃. When it was heated to60℃, thermostatic reaction began. And the phosphate functional monomer (HPAM) could be produced after reaction4h.The results showed that the dosage of HPAM was3-4%, the polymerization stability of the emulsion was well, the adhesion, the water resistance, the corrosion resistance, and the burnish of emulsion film were effectively improved, even no flash rust appearance.At the same time, the emulsion modified by the monomers such as the hydroxyl value, AAEM, epoxy resin E-44and silicon monomer AC-75accounted for1.5%,7%,6%and5%respectively. The modified emulsion and its film showed the good stability, mechanical properties and corrosion resistance. The modified method had not been reported.3. According to the film forming mechanism of the modified emulsion on the metal surface, the result showed that the mechanical properties and the corrosion resistance of the low drying temperature varnish film were better by using the modified emulsion and the waterborne isocyanate EasaquaTM XM502as the curing agent, when the molar ratio of (-OH) and (-NCO) was0.8to1. Moreover, the mechanical properties and the corrosion resistance of the Stoving Varnish film were better by using the modified emulsion and the methylated amino resin R717following the mass ratio was6to1.4. Investigate the influence of different grinding process and different dispersant dosage, thixotropic agent on the performance of the colorant. The adding order of the raw material was water, wetting-dispersing agent, pH regulator, carbon black, zinc phosphate, aluminium trippolyhosphate, barium sulfate, reolosil and antifoaming agent. The stroage stability of the colorant was good and fineness degrees was less than25μm when the dispersant Hw-1blending with the dispersant As-28were choosed as the wetting dispersants, the adding amount was50%of pigments and fillers and the grinding time was4h. Compared the performance of the waterborne anti-corrosion coating by the SEM and electrochemical testing. The result showed that the mechanical properties, the ageing resistance performance and the adornment performance of the waterborne anti-corrosion coating was good when PVC was35%, the coating corrosion potential Ecorr was0.533V, the corrosion current density Jcorr was about3.754×10-4A·cm-2, better than the other PVC proportion. |
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