What is the principle of rust reversion of epoxy zinc-rich primer

Epoxy zinc-rich primer is a special coating made of epoxy resin and zinc powder as the main raw materials, supplemented by thickeners, fillers, additives and solvents. The paint has the characteristics of fast drying, strong adhesion and strong anti-corrosion ability. It is mainly used for steel pipes, storage tanks, steel structures, containers, etc., so what is its rust return principle?

I. External Standards

1. Epoxy zinc-rich primer cannot be used in the natural environment where the relative air humidity exceeds 85%; in the case of high environmental humidity, a layer of shrinkage water will be produced on the surface of the steel, which is invisible to the human eye. In this case, it is easy to rust during the construction of the project.

2. The surface roughness of the steel does not match the zinc powder composition of the epoxy zinc-rich primer. In the surface layer with insufficient surface roughness, the zinc-rich primer with high zinc powder content in engineering construction will also rust due to insufficient adhesion in rainy days.

3. The paint layer is too thick and too thin, and the surface roughness is too low. The epoxy zinc-rich primer is used as a topcoat for anti-corrosion and anti-rust treatment, and the coating thickness is about 50μm.

4. The sandblasting process cannot be carried out with sea sand; sea sand contains a variety of chloride ions, which are the key elements of the electrochemical reaction.

Second, the essential standard

1. Epoxy zinc-rich primer is currently a widely used architectural coating in the heavy-duty anti-corrosion industry, but there are many zinc content that does not meet the national industry standard (the national standard wet film zinc powder content is 70%).

2. Insufficient epoxy resin composition leads to insufficient adhesion of the paint layer to the steel. (Too many pigments and fillers.)

3. Anti-rust treatment and anti-corrosion effect of epoxy zinc-rich primer, in which zinc powder component, epoxy resin component and epoxy curing agent play a key role. It is unlikely that the price of epoxy zinc-rich primers with excellent anti-rust treatment and anti-corrosion effect is very low.