Under the protection requirements of many harsh industrial environments and outdoor facilities, the multi-layer coating system of polymer antioxidant anti-corrosion coating shows unique advantages and importance.
First of all, the design of the multi-layer coating system is based on the layered construction of different coating functions. As the part in direct contact with the substrate, the key role of the primer layer is to provide good adhesion and basic anti-corrosion performance. For example, primers containing active pigments such as zinc phosphate can react chemically with the metal substrate to form a dense passivation layer, effectively preventing the erosion of corrosive media, and providing a solid adhesion foundation for subsequent coatings. The intermediate coating focuses on further enhancing the anti-corrosion ability and filling the tiny defects on the surface of the primer. It usually has a high solid content and good barrier properties. For example, the use of thick paste epoxy coatings can effectively block the penetration of corrosive factors such as oxygen and moisture, and make the coating surface smoother through its own filling properties. The topcoat layer mainly bears the functions of anti-oxidation and weather resistance, and often contains highly effective antioxidants and UV absorbers. Hindered amine antioxidants can capture free radicals and delay the oxidative degradation of polymers, while special acrylic topcoats can resist aging caused by ultraviolet radiation and protect the lower coating and substrate.
Secondly, the synergistic effect between the layers significantly improves the overall anti-corrosion and anti-oxidation effect. The primer and the middle layer are closely combined to form a continuous protective barrier. The good adhesion of the primer ensures the stability of the entire coating system on the substrate, and the middle layer strengthens the density and durability of this barrier. The middle layer and the topcoat cooperate with each other. The middle layer provides a flat and stable supporting surface for the topcoat, which is conducive to the uniform coating of the topcoat and its anti-oxidation and weathering functions. At the same time, the anti-oxidation performance of the topcoat in turn protects the middle layer from oxidation damage, prevents cracking and peeling of the coating caused by oxidation, and thus prolongs the service life of the entire coating system.
Furthermore, the design of the polymer antioxidant anti-corrosion coating multi-layer coating system also needs to consider the special requirements of different application scenarios. In the marine environment, facing the challenges of high salt spray, high humidity and strong water flow scouring, the primer can be a zinc-rich primer with excellent salt spray resistance, the middle layer uses a thick paste polyurethane coating with strong scouring resistance, and the topcoat focuses on weather resistance and resistance to seawater erosion; in the chemical industry environment, for various strong corrosive media such as strong acids and alkalis, the primer, middle layer and topcoat must have corresponding chemical corrosion resistance, and the layers can work together to resist the erosion and penetration of various chemical substances.
Finally, the construction process and quality control of the multi-layer coating system are also key links to ensure the synergistic effect. The process parameters such as the coating thickness, drying time, and coating interval of each layer of coating need to be strictly controlled to ensure good bonding and performance between the layers. At the same time, during the construction process, attention should be paid to the influence of environmental conditions, such as temperature and humidity, to avoid coating defects caused by improper construction, thereby affecting the anti-corrosion and anti-oxidation synergistic effect of the entire multi-layer coating system.
