Study On Preparation Of Zinc Flake And Zinc-Based Waterborne Anticorrosive Coatings

The study focused on the manufacture technology of zinc flake by vibration mill, the physical characteristics of the interior and imported zinc flake, the surface treatment technology of zinc flake. Further more the preparation technology and the composition component of zinc-based waterborne anticorrosive coatings was investigated. The main results are as follows:1.According as the characteristic of the vibration mill, the results of comparison between dry and wet milling method show that the wet milling method is more favorable. The process of vibration grinding was studied and discussed by testing the water covering capacity,the loose density and the size distribution, it's could be find that the procedure of grinding contains flaky and cracked deformation, the grain size of zinc flake increased at the beginning and decreased subsequent.2.The important parameters of milling process were investigated and a set of optimized technique was developed. The grain size of zinc flakes prepared by this technology is similar to the imported zinc flake and with high value on the ratio between diameter and thickness. It can be used to prepare zinc-based waterborne anticorrosive coatings.3. Compared to the imported zinc flake, the surface state of interior was roughness, the ratio between diameter and thickness and the water covering power was low, and the dispersion stability in the water solution was poor.4.The interior zinc flake was surface treatmented by mechano-chemistry polishing method. The effect of surface modifier on the dispersion stability was discussed, the results indicated that the titanium coupling agent was more effective than other modifying agent, the optimally additions were 1%. Wt. Through the surface treatment the surface of zinc flake was well flattened and polished, the water covering power was improved obviously, the dispersion stability of zinc flake surpassed the level of imported.5.By right of the well dispersion stability in water solution, just a small amount of wetting agent was needed to accelerate the wetting speed during the process of mixing compositions and it's dispensed with any other dispersant agent. With adjustment of pH value of chromic acidsolution the corrosion speed of zinc flake in the composition solution was reduced availably, the reducing reaction between organic reducing agent and chromic acid was controlled and the stability of composition and the performance of coatings were improved effectively. The best pH value of chromic acid solution is 2.0.6.The effect of essential components on the performance of composition and coating was analyzed and the recipe of composition was optimized by orthogonal test. The coatings prepared with optimum conditions has excellent stain resistance, good surface appearance and bond strength.