How to avoid orange peel caused by powder coatings

In actual work, active propellants or leveling agents are often used to improve the appearance of the film to eliminate the appearance of orange peel, shrinkage, and other defects. The active propellant with good function can reduce the melt viscosity and then help melt mixing and pigment dispersion to advance the wetness of the substrate. The active leveling of the coating helps to eliminate the appearance defects and facilitate the release of air. The relationship between the amount of activity modifier and its effect should be investigated. Lack of its dosage will cause shrinkage and orange peel, while excessive dosage will cause loss of gloss, haze, and adhesion to the upper layer. The general activity modifier participates in the premix. They or resin masterbatches are adsorbed on the inorganic carrier in powder form. When the amount of this additive in powder coating is as low as 0.5 to 1.5%, it can work well.

Promoting activities and leveling can reduce or prevent orange peel. The system uses lower melt viscosity, prolongs the leveling time during the solidification process, and higher surface tension can move forward and level. Manipulating the surface tension gradient is an important parameter to reduce orange peel. At the same time, it is necessary to manipulate the average surface tension of the coating film to obtain a smaller surface area.