Powder coating will be affected
1. Selection of pigments:
The oil absorption and increasing dosage of pigments, the oil absorption of inorganic pigments is much smaller than that of organic pigments, so we can use inorganic pigments to adjust the color to avoid using organic pigments as much as possible, and the total proportion of various pigments should be covered according to customers. Adjustment required. Even if the pigment with low oil absorption is added in excess, it will cause poor leveling.
2. Melt viscosity:
For thermosetting
powder coatings, in the process of melting activity, along with the cross-linking curing reaction, the higher the temperature, the faster the curing reaction, the faster the system viscosity rises, the shorter the activity time, and the more restricted the leveling. Therefore, when selecting resins, we try to choose resins with lower viscosity and slower reaction activity, so that the coating can have sufficient time to level.
3. Leveling aids:
Add appropriate leveling additives to the formula of
powder coatings. When the powder coating is melted, these additives can quickly reduce the surface tension of the coating, promote the rapid movement of the coating before curing into a film, and eliminate or reduce orange peel, brush marks, and ripples. , shrinkage holes and other appearance defects.
4. Selection of fillers:
As we all know, fillers in powder coatings can not only reduce costs, but also improve the performance of
powder coatings, especially wear resistance, but if our technicians choose improper fillers, they can also give powder leveling a fatal blow , The mesh number of the filler is large or small, and the oil absorption capacity is divided. In general, the oil absorption capacity of barium sulfate is much smaller than that of calcium carbonate, kaolin, mica powder, quartz powder, silicon powder, etc., barium sulfate The finer the particle size, the higher the gloss, the finer the particle size of other fillers, the greater the oil absorption and the worse the leveling.
