Organic zinc-rich paint
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The most commonly used organic zinc-rich paint is epoxy zinc-rich paint; there are also zinc-rich paints based on chlorinated rubber, among others. However, since they are thermoplastic resins that soften when exposed to heat, they are not widely used. Epoxy zinc-rich primer is an epoxy primer prepared by using zinc powder as the rust-inhibiting pigment, epoxy resin as the base material, polyamide resin or amine adducts as curing agents, along with appropriate mixing solvents. The content of zinc powder in such primers is usually over 85%, so as to form a continuous and dense coating in contact with the metal. Epoxy zinc-rich primer should be applied after sandblasting to Sa2½ (ISO8501-1). On the surface of organic zinc-rich coatings, it is compatible with most paints (except alkyd paints, which will saponify). It is an excellent primer in multi-coating systems, whether for new construction or on-site repairs. It dries quickly, with a relatively short interval between reapplications. It has good adhesion, is impact-resistant, and can withstand temperatures up to 120°C. Its wear resistance is also very good. The disadvantages of epoxy-based zinc-rich coatings compared to inorganic zinc-rich coatings are, first, a relatively weaker cathodic protection effect due to their lower electrical conductivity, and second, a lower acceptable chloride content. This is his biggest drawback when used in marine environments.
Organic zinc-rich paints are usually epoxy zinc-rich paints, with a small amount of chlorinated rubber zinc-rich paints as well. The main components of epoxy zinc-rich primers include a high content of zinc powder, epoxy resin, and polyamide resin or amine adduct curing agents. This coating makes close contact with the metal surface, dries rapidly, allows for short intervals between recoatings, possesses good adhesion and heat resistance, can withstand temperatures up to 120°C, and has excellent wear resistance. However, epoxy-zinc-rich coatings have a relatively weak cathodic protection effect, low electrical conductivity, and low tolerance to chlorides, which are significant drawbacks in marine environments. .