In principle, the additive used for powder coating must be solid. If the additive is a solid material with extremely low viscosity or melting point, when the additive amount exceeds 2%, it has poor storage stability in summer and is easy to caking. Therefore, the choice of auxiliaries is very limited. Let ’s follow Xiaobian to briefly understand the choice of additives for coating materials.
Powder coatings tend to shrink during baking and curing. To overcome the disadvantages, leveling agents are added to the coating. The main function of the leveling agent is to reduce the surface tension after melting, so that the coating can be quickly leveled before curing into a film.
If the viscosity of the powder coating is too low, the coating coverage of the coating edge is not good, which will affect the corrosion resistance or electrical insulation of the coating edge. In order to improve the edge coverage of the film and make the thickness of the film close to the thickness of the plane, the addition of silica is commonly used. The addition can control the viscosity of the coating that usually melts and flows, and prevents the coating from being too thin or sagging.