Summary:In powder coating formulations, although the role of filler is not as important as that of resin, curing agent and pigment, it is also an indispensable part in
In powder coating formulations, although the role of filler is not as important as that of resin, curing agent and pigment, it is also an indispensable part in most formulations. When designing the powder coating formula, the following aspects should be considered in the selection of filler type and dosage.
(1) According To The Use Of Powder Coating
For outdoor powder coatings, fillers with good weather resistance, good chemical stability and not easy to pulverize shall be selected; The requirements for indoor powder coatings are not so strict, but the powder coatings used for corrosion protection should be filled with fillers with good performance of acid resistance, alkali resistance, salt resistance and water resistance.
(2) According To The Performance Requirements Of Powder Coating
When the film is required to have a good leveling property, the filler with small oil absorption and good dispersion should be selected. It is better to use the filler treated with coupling agent, fatty acid and other surface treatment agents or ultra-fine filler, which is conducive to the dispersion of the filler;
In order to reduce the volume concentration of fillers in the formula, precipitated barium sulfate with high density and good dispersion is selected;
In order to reduce the density of powder coating, light calcium carbonate with low density is selected;
In order to improve the film hardness, kaolin with high hardness is selected;
For general powder coatings requiring matting, matting fillers, such as barite powder, can be selected. The problem that should be noted here is that for the powder coating system with matting agent, the matting filler cannot play a supplementary role in matting, and the film gloss is higher than that of the powder coating prepared with ordinary filler;
For sand grain powder coating, bentonite can be used;
In order to improve the electrical insulation performance, quartz powder or mica powder is selected;
In lead-free powder coatings, calcium carbonate can be selected.
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