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替换城市 Principle and influencing factors of special UV curing defoamer agents for paints(2)




There are many types of leveling agents, and the types of leveling agents used for different coatings are also different. High boiling solvent or butyl cellulose can be used in solvent based finishing agents. Surfactants or polyacrylic acid, carboxymethyl cellulose, etc. are used in water-based finishing agents.

Good paint defoamers not only have a good defoaming effect in paint systems, but also maintain defoaming ability at room temperature and under heating environments. In addition, it cannot be compatible with foam system. If the compatibility is good, it will help to produce foam. While the paint UV curing defoamer has good dispersibility in the foaming system, specifically refers to the uniform and smooth diffusion of the defoamer on the surface, which can cover the foam to achieve the elimination effect. Its working principle is to reduce the surface tension of the liquid around the foam, so that small foam can gather into large foam, and finally foam will burst.



Influencing factors of special defoaming agents for paints:

surface tension

The study of foam can be traced back to Plato's time, but for hundreds of years, people have not formed a unified understanding of the definition of foam. American colloid chemist L · I · Osipow and Dow Corning's R · F · Smith defined foam from the density of foam; Japan's Koichi Ito defined foam from the perspective of foam structure, but ignored the correlation between bubbles; Professor Zhao Guoxi, a famous surface physicist in China, defined foam as: foam is a dispersion system in which gas is dispersed in liquid, gas is a dispersed phase (discontinuous phase), and liquid is a dispersion medium (continuous phase). Bubbles in liquid rise to the liquid surface, forming a bubble aggregate composed of a small amount of liquid that separates gas with liquid film. Scholars at home and abroad agree that foam itself is a thermodynamic unstable system. When the gas enters the solution containing surfactant, it will form a long-term stable foam system.


替换城市  The level of coating surface tension has a significant impact on defoaming agents. The surface tension of defoaming agents is lower than that of coatings, otherwise they cannot have defoaming and antifoaming effects. The surface tension of a coating is a variable factor, so when selecting defoamers, it is necessary to maintain a constant surface tension, taking into account the surface tension variation factor.

Effects of other additives

Most surfactants used in coatings tend to be functionally incompatible with UV curing defoamer. In particular, emulsifiers, wetting and dispersing agents, leveling agents, thickeners, etc. can have an impact on the effectiveness of defoamers. Therefore, when coordinating various additives, it is necessary to pay attention to the relationship between different additives and select a good balance point.