Powder coatings and water-based coatings, light-curing coatings, and high-solids coatings are known as the four new environmentally friendly coatings. As an important branch of coatings, powder coatings are widely used in the fields of household appliances, general hardware, aluminum profiles and automobiles due to their high efficiency, environmental protection and economic characteristics, as well as excellent decorative properties and corrosion resistance.

Pinholes, that is, bristles, are small needle-like holes, which are small coating film defects that are easy to appear during the curing process. Its appearance not only affects the appearance of the coating film, but also may seriously affect the corrosion resistance of the coating.

Due to its unique application conditions, thermosetting powder coatings generally exhibit higher curing temperature (above 120 ° C), thicker coating film thickness (above 50u), shorter curing time (within 20min), and higher initial melting Viscosity (no solvent dilution) and other characteristics. Practice shows that it is precisely because of the above characteristics that pinholes are more likely to occur in powder coatings than solvent-based coatings with lower initial viscosity during curing. It is worth mentioning that, because the viscosity of the system does not increase, the probability of pinholes is relatively small.