Zinc oxide is a basic compound that acts on a small amount of free fatty acids to form a zinc soap, which tends to thicken the coating, and dissolves in the case of inorganic acids or acetic acid.
Zinc oxide has a high refractive index, absorbs ultraviolet light, and has strong coloring power and hiding power, but the color is pure white, non-powdered, and has good light and heat resistance; it can react with carboxy in paint. The acid ion forms a coordination compound to reduce the sensitivity of water in the coating film. Therefore, zinc oxide can improve the weather resistance and powdering resistance of the coating film, and is suitable for exterior wall coatings. Zinc oxide makes the product film flexible, firm and impervious to water, thus preventing metal corrosion. However, it is not advisable to mix with the base with more free acid to avoid producing more zinc soap, making the paint thick and not easy to apply.
Zinc oxide is used in anti-corrosion or marine coatings to form dense zinc-titanium compounds that reduce the rate of further penetration of corrosive media. Mainly plays a role in rust prevention.
Moreover, zinc oxide is mildew resistant and inhibits the growth of microbial fungi.
In general, ceramics and cans are coated with indirect zinc oxide with small particle size and high purity. Indoor coatings and latex coatings use needle-like direct method zinc oxide to make the oil absorption value higher and improve the suspension performance. .