Requirements of electrostatic spraying for powder coating equipment

Electrostatic spraying Electrostatic spraying is a common process for powder coating equipment in powder coating to ensure the smooth implementation of the electrostatic spraying process and obtain a high-performance coating film. What parameters and related parameters should be paid attention to when powder coating equipment is electrostatically sprayed powder coating?

①Particle size of powder coating: The significant difference between powder coating and solvent-based coating lies in the difference of dispersion medium. In solvent-based coatings, organic solvents are used as the dispersion medium; while in powder coatings, purified compressed air is used as the dispersion medium. When the powder coating is sprayed, it is in a dispersed state, and the particle size of the coating cannot be adjusted. Therefore, the fineness of powder particles suitable for electrostatic spraying is very important.

②Resistivity and betweenness of powder coating: For the powder electrostatic spraying process, it is necessary to consider that the powder coating particles accept charge, maintain charge and charge distribution, which directly affects the adsorption force and deposition efficiency of the powder on the workpiece. In addition, it is important that the uncured powder coating must withstand the mechanical impact of the conveying mechanism without shedding the powder.

③Moisture content of powder coating: The hygroscopicity of powder coating directly affects the resistance and dielectric constant of the powder itself. If the powder is very hygroscopic, it will clump together. This is not possible with electrostatic spraying. Generally, after moisture absorption, in addition to affecting its charging performance, it will also reduce the fluidity and film-forming properties of the powder, making the coating film not smooth or even difficult to adsorb on the workpiece, and the coating film will produce bubbles and pinholes.

④ Stability of powder coating: The stability of powder coating refers to whether the powder will agglomerate during storage or use, the leveling property will deteriorate, the electrification effect will deteriorate, the orange pattern of the coating film will be obvious, and the gloss will deteriorate. Weakening, pinholes, occurrence of air bubbles, etc.