Preparation Of Solvent-free Heavy-duty Epoxy Coating

With the economic development and increase of people’s environmental awareness, the traditional anti-corrosion coating has been unable to meet the market demand. Solvent-free heavy-duty epoxy coating have both excellent corrosion-resistance and good adhesion, and it is also a kind of environmental-friendly coating. It will become one most important part of the field of heavy anti-corrosion coatings in the future. In this paper, the solvent-free heavy-duty epoxy coating was made with low molecular epoxy resin selected as the film-forming material, the appropriate curing agent and anti-rust pigment.This experiment has determined the type and dosage of active diluent. Active diluent has a certain influence on the properties of the coating.The additive amount of reactive diluent should be in 5% ~ 10%, adding less amount will increase the coating viscosity and affect the construction of coating; adding more additive amount will affect the coating properties of shock-resistance, flexibility and adhesion. Curing agent is the main film-forming material of coating, and it has a great influence on the properties of the coating. The experiment shows that using the compounding method of curing agent D can not only improve the physical properties of coating, such as flexibility and glossiness but also improve the corrosion resistance of the coating. With the help of the analysis of orthogonal test results, the author determined the main pigments and fillers addition amount, i.e. precipitated barium sulfate 50, zinc phosphate 20, mica powder 20 and talcum powder 22. The P/B has great influence on corrosion resistance of coating. The low P/B can not form a dense coating, which has poor corrosion resistance, the oversize P/B could improve the corrosion resistance of the coating, but decline the flexibility and glossiness of the coating. Finally, the effect of the coating thickness on the corrosion resistance of the coating was studied. The results showed that with the increase of the coating thickness, the protective performance of the coating can be improved. According to the analysis of the heavy anti-corrosion coating on the international market and domestic market currently and combining the manufacturing technique of the solvent-free epoxy coating with heavy anti-corrosion in technically and economically and eventually determined the feasibility of the industrial production of technique.In this experiment, the final formula of the solvent-free heavy-duty epoxy coating is displayed as follow: epoxy resin is 30%- 50%, reactive diluent is 5% ~ 10%, pigments is 45% ~ 65%, P/B is 1.5, and accessory ingredient is 1% ~ 4%, curing agent is D. The film formation of coating can once reach 800 μm, solid content is over 99.5%, the flexibility reaches 2 mm, and the hardness is 4H. This type of coating has both excellent corrosion-resistance and low VOC emissions, which is an environmental-friendly coating.