Compared with general anti-corrosion coatings, heavy-duty anti-corrosion coatings have the following characteristics:
Heavy-duty anti-corrosion coatings must be composite coating systems. Practice has proved that hundreds of types of heavy-duty anti-corrosion coatings produced by domestic and foreign coating manufacturers must adapt to cross-sea bridges, harbor projects, offshore platforms, various storage tanks and large steel structure projects. Several coatings are sprayed to form a heavy-duty anticorrosive coating composite coating system, which means that the high-performance primer, middle coat, and top coat need to perform different functions to give full play to the overall effect of the composite coating.
The most commonly used interlayer paint is room temperature curing epoxy mica primer. The paint is made of epoxy resin as a film-forming substance, added with mica iron oxide ash, fillers, additives, etc., and polyamide resin is used as a curing agent. It is a two-component high-build primer. The gray mica iron oxide is used in the thick build epoxy mica primer, which is arranged in layers in the paint film, which increases the water vapor penetration resistance. It can be sprayed with a high-pressure airless sprayer up to 100-500μm thick paint film at a time . It is worth mentioning that when the zinc powder on the zinc-rich primer is corroded, alkaline deposits are generated to cover the surface of the primer, so the intermediate paint should have good alkali resistance.
