Electrostatic spraying Electrostatic spraying is a common process for powder coating equipment in powder coating, in order to ensure the smooth implementation of electrostatic spraying process and obtain high-performance coating film. What parameters and related parameters should be paid attention to in the electrostatic spraying of powder coatings by powder coating equipment?
①Particle size of powder coating: The significant difference between powder coating and solvent-based coating is the different 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. Powder coatings are in a dispersed state when sprayed, and the particle size of the coatings cannot be adjusted. Therefore, the fineness of powder particles suitable for electrostatic spraying is important.
②Resistivity and betweenness of powder coating: For the powder electrostatic spraying process, it is necessary to consider that the powder coating particles accept the charge, maintain the charge and charge distribution, which directly affects the adsorption force and deposition efficiency of the powder on the workpiece. In addition, it is important to The point is that the uncured powder coating must withstand the mechanical shock of the conveying mechanism without shedding powder.
③Moisture content of powder coating: The hygroscopicity of powder coating directly affects the resistance and dielectric constant of powder itself. If the powder is heavily hygroscopic it will clump together. This is not possible for electrostatic spraying. General moisture absorption, in addition to affecting its charging performance, will also reduce the fluidity and film-forming properties of the powder, so that the coating film is 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 characteristics will become worse, the charging effect will become worse, the orange pattern of the coating film is obvious, the gloss is weakened, and the pinholes The occurrence of bubbles, etc.
