What factors affect the leveling of powder coatings

Update:07-05-2021
Summary:

1. The choice of pigments: Before we match colors, we m […]

1. The choice of pigments:

Before we match colors, we must not only match various color shades, but also consider the oil absorption and increased dosage of various pigments. The oil absorption of inorganic pigments is much smaller than that of organic pigments, so we can use inorganic Avoid using organic pigments as much as possible for the colors adjusted by pigments. The total proportion of various pigments should be adjusted according to the customer's covering requirements. Even if the pigment with low oil absorption is added in excess, it will cause poor leveling.

2. Melt viscosity:

For thermosetting powder coatings, during the melting activity process, 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 leveling performance is restricted. Therefore, when choosing a resin, try to choose a resin with a lower viscosity and slower activity, so that the coating has sufficient time to level.

3. Leveling additives:

Add appropriate leveling additives to the powder coating formulation, such as Lacey H98, Nanhai 588, etc. When the powder coating is melted, these additives can quickly reduce the surface tension of the coating, and promote the rapid movement of the coating before it is cured to form a film. Reduce appearance defects such as orange peel, brush marks, ripples, and shrinkage holes.

4, the choice of filler:

As we all know, fillers in powder coatings can not only reduce costs, but also improve various functions of powder coatings, especially wear resistance, but if our technicians choose fillers improperly, it can also give a fatal blow to powder leveling. , The number of fillers is large or small, and there are oil absorption. In general, the oil absorption of barium sulfate is much smaller than calcium carbonate, kaolin, mica powder, quartz powder, silica 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.

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