Study On Synthesis And Corrosion Resistance Performance Of Solventless High Building Epoxy Coating

Metal corrosion involves all fields of national economy and national defense construction, not only causes huge economic losses but also threatens the safety of human life and property. Ocean is the most harshed natural environment, metal corrosion problem in ocean is particularly acute. Coating is one of the main measures for marine anti-corrosion. As the marine environment is harsh,environmental friendly and high effective protection such as high building coating is the major development trend of marine coating.In this paper, the solventless high building epoxy coating was prepared with low molecular weight epoxy resins selected as the base material, zinc phosphate and micaceous iron oxide gray as the mainly antirust pigments. The effects of PVC, the mass ratio of antirust pigments and the reactive diluent content on the physical properties and corrosion resistance of coating were mainly studied through basic properties test, EIS and the neutral salt spray test. Major research conclusions were showed as follows. The solid content reached 99%, and met to the environmental needs. PVC in the coating formulation design is a very important parameter. The coating exhibited good performance of corrosion resistance when the PVC was less than 8%. When the value of PVC was 8% and the mass ratio of zinc phosphate to micaceous iron oxide gray was about 1:4, the coating exhibited good performance of corrosion resistance. Reactive diluent could effectively reduce the paint viscosity. When the reactive diluent content was less than 2%,the coating had appropriate viscosity and was suitable for thick coating (up to 300μm or more), and showed a good anti-corrosion effect. By analyzing the changes of coating resistance it could be found that coating resistance began to recover slowly when the coating system immersed in NaCl solution for a certain time. It had a certain degree of corrosion inhibition. Based on the above, considering the anti-corrosion performance of coatings, construction performance and cost factors, the optimum ratio of the coating was ultimately determined as follows: low molecular weight epoxy resins 45 wt.~65 wt.%, PVC 6%~10%, the mass ratio of zinc phosphate to micaceous iron oxide gray 1:4; the reactive diluent content 1 wt.%~2 wt.%; promoters 1 wt.%~2 wt.%. The solventless high building epoxy coating was environmental friendly coatings because it didn't contain organic solvents, and was suitable for thick coating, had good basic properties and anti-corrosion performance, and could be applied in the harsh marine corrosion environment.