替换城市 Principle and influencing factors of special Free of silicone defoamers agents for paints(4)

When the paint is baked at high temperature at room temperature, its viscosity will drop at the beginning, and bubbles can move to the surface. However, because of the volatilization of solvent, the curing of paint, and the increase of surface viscosity, the foam will become more stable and retain on the surface, resulting in shrinkage and pinholes. Therefore, the baking temperature, fixing speed, and solvent volatilization rate also have an impact on the effect of defoamer.

acrylate

UV

water-based

Polydimethylsiloxane
Although it has good surface state control capabilities, it has many shortcomings, such as poor compatibility, which can affect the gloss of the coating film, and often lead to shrinkage, interlayer adhesion issues, and so on. The molecular weight of polydimethylsiloxane is different, and its compatibility and use are also different. Compared with silicone oil, organic modified polydimethylsiloxane has obvious advantages, not only retaining the advantages of siloxane, but also overcoming its disadvantages with modifiers, exerting many special functional effects. The key to the performance and use of modified siloxanes is their molecular weight, type, type of modified compound, and position in the molecule. There are many ways to modify them

Solid content, viscosity, elasticity of paint

替换城市  High solid thick film, high viscosity and high elasticity coatings are very difficult to defoamer. In these coatings, defoamer diffusion is difficult, microbubbles become larger slowly, foam migration ability decreases, foam viscoelasticity is large and many other adverse defoamer factors. Foam in these coatings is very difficult to eliminate, so defoamer and defoamer should be used together.