替换城市 Principle and influencing factors of special No Foam agents for paints(2)
dispersant
dispersant
Defoamer is an additive for eliminating foam. A large amount of foam will be produced in the production and application process of coatings, textiles, medicine, fermentation, paper making, water treatment, petrochemical and other fields, which will affect the product quality and production process. Based on the inhibition and elimination of foam, a specific amount of defoamer is usually added to it during production
epoxy
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 No Foam 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:
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.
surface tension
gold
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.
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Effects of other additives
Most surfactants used in coatings tend to be functionally incompatible with No Foam. 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.