Direct zinc oxide plays a multifaceted role in improving the corrosion and weathering properties of coatings. Its unique chemical properties make it a crucial ingredient in coating formulations. A coating's corrosion and weathering capabilities directly impact its lifespan and protective effectiveness. Direct zinc oxide, through its synergistic effect with other ingredients, can fundamentally enhance a coating's resistance to environmental corrosion.
In terms of corrosion protection, direct zinc oxide forms a dense protective film on the coating surface. Once applied to the substrate, direct zinc oxide reacts with moisture and carbon dioxide in the air to form stable compounds. These compounds fill the coating's micropores, reducing the pathways for moisture, oxygen, and corrosive media to penetrate the substrate. This dense structure acts as a barrier, effectively blocking harmful external substances from contacting the substrate, thereby reducing the likelihood of corrosion. It is particularly effective on metal substrates.
Direct zinc oxide also enhances the coating's corrosion resistance by inhibiting microbial growth. In humid environments, microorganisms such as mold and algae can easily grow on coating surfaces. The metabolic products of these microorganisms can damage the coating structure, accelerating aging and peeling. Direct zinc oxide has a certain antibacterial effect, inhibiting the growth of microorganisms on the coating surface, reducing microbial erosion, maintaining the coating's integrity and protective properties, and extending the coating's effective protection period.
Direct zinc oxide's UV absorption capacity plays a key role in improving weather resistance. Ultraviolet rays in sunlight are one of the main factors that cause coating aging. Long-term exposure to UV rays can degrade the polymer materials in the coating, causing fading, chalking, and cracking. Direct zinc oxide absorbs UV rays and converts them into harmless heat, which it dissipates. This reduces UV damage to the coating's internal structure, slows the aging process, and maintains the coating's color and physical properties.
Direct zinc oxide also enhances the coating's resistance to temperature fluctuations and water resistance. In environments with large temperature fluctuations, coatings are prone to cracking or flaking due to thermal expansion and contraction. Direct zinc oxide has good compatibility with the resin and other components in the coating, improving the coating's elasticity and toughness, making it less susceptible to deformation during temperature changes. At the same time, its presence reduces the coating's water absorption rate and penetration, preventing problems such as blistering and flaking caused by water absorption, and improving the coating's stability in humid environments.
During the film-forming process, direct zinc oxide helps improve the coating's density and adhesion. It chemically reacts with certain components in the coating, promoting cross-linking of the film-forming substances, resulting in a more uniform and dense coating structure and reducing internal defects. This dense structure not only enhances the coating's physical and mechanical properties but also improves adhesion to the substrate, preventing the coating from detaching from the substrate surface and ensuring long-term, stable protection.
Furthermore, direct zinc oxide's chemical stability ensures the coating's weather resistance. It is resistant to chemical reactions with other substances, maintaining its performance in a variety of complex environmental conditions, without compromising its protective effectiveness due to changing environmental factors. This stability enables coatings containing direct zinc oxide to adapt to diverse climates and operating environments, maintaining excellent corrosion and weather resistance in both hot and humid climates and cold and dry regions.
