替换城市 Principle and influencing factors of special No Foam agents for paints(3)

dispersant

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.

Baking temperature

Leveling principle
The compatibility of acrylic leveling agents is an important indicator of their ability to control the surface state of the coating film. The compatibility is too good to dissolve in the coating film, which will not form a new interface on the surface of the coating film and provide no leveling effect; Due to poor compatibility, it is impossible to uniformly distribute on the surface of the coating film, which can gather together and easily cause shrinkage defects. It can reduce the gloss of the coating film and produce adverse side effects such as fog and shadow. Only with ideal controlled compatibility can a new interfacial layer be formed on the surface of the coating film, playing a leveling role

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.