Difference between epoxy iron red primer and epoxy zinc-rich primer

Epoxy iron red primer : a two-component anticorrosive primer made of epoxy resin, anti-rust pigment, curing agent, etc.

Epoxy zinc-rich primer: Epoxy zinc-rich primer is an anticorrosive coating composed of epoxy resin and xinfen as the main raw materials, thickener, filler, auxiliary agent, solvent and so on.

1. Difference in antirust principle:
The difference between epoxy iron red primer and epoxy zinc-rich primer is mainly that the principle of rust prevention is different.

  Epoxy iron red primer anticorrosion principle: passivation and corrosion inhibition of iron red pigment

The anticorrosion of epoxy iron red primer depends on the passivation and corrosion inhibition of iron red pigment on steel , and the action of antirust pigment on metal surface to passivate or generate protective substances to improve the protective effect of the coating. Corrosion inhibition can make up for the lack of shielding effect of screen paint . In turn, the shielding effect can prevent the loss of corrosion inhibitor ions and make the corrosion inhibitor stable and lasting.

Epoxy zinc-rich primer anti-corrosion principle: cathodic protection

If there are more active metal (metal with lower electrode potential) powder than steel in the coating, such as xinfen or aluminum powder, they can form cathodic protection of sacrificial anode for steel, similar to the principle of galvanizing , as long as these are active The content of the metal powder is such that the metal powder particles and the metal powder and the steel substrate reach point contact, so that the steel can be protected from corrosion. Zinc-rich coatings are typical of such functional coatings.

2. Difference in antiseptic effect

From the perspective of anti-corrosion effect, the epoxy zinc-rich primer (national standard) is better. Generally, the anti-corrosion period of more than ten years requires epoxy zinc-rich primer, while the general anti-corrosion can use epoxy iron red primer , And personally think that the non-national standard epoxy zinc-rich primer with too low zinc content is not as good as the epoxy iron red primer. If the zinc content is too low, it will not play a role in cathodic protection.

  3. Use difference

Epoxy zinc-rich primer is used for anticorrosion of steel structure under the condition of long-term anticorrosion and severe corrosive environment. It is applied to anticorrosion of steel structure under moderate to severe corrosive environment.

  Epoxy iron red primer is used in general anticorrosion and general corrosive environment, mild or moderate corrosion environment steel structure surface anticorrosive primer.

4. Different requirements for surface treatment

Epoxy zinc-rich primers have higher requirements for the treatment of substrates. Sa2.5 grades or higher are required. Epoxy iron red primers have relatively lower requirements for substrate treatments.

5. Supporting differences

For the matching, the matching of the two is similar, both can be matched with epoxy cloud iron intermediate paint / acrylic topcoat / polyurethane topcoat / fluorocarbon topcoat, etc., but epoxy zinc-rich primer is generally not compatible with alkyd topcoat.

  6. Price economy comparison
In terms of price, the national standard epoxy zinc-rich primer is high in price, the epoxy iron red primer is low in price, and the economical epoxy iron red primer is far superior to the epoxy zinc-rich primer. If selected, it can be based on anti-corrosion requirements and budget Situation to consider which primer to choose.

  Such as: major projects, port machinery , heavy machinery, oil storage tanks, ships generally choose epoxy zinc-rich primer, mildly corrosive environment steel structure plant, equipment , construction machinery and simple derusting renovation project optional ring Oxygen red primer.

  Of course, the service life needs to be considered: if a port machine is expected to be demolished after 3 years of use, it is not necessary to use epoxy zinc-rich primer.