Electrostatic atomization is mainly used in paint atomization. In electrostatic spraying, under the action of high-voltage electrostatic field, the phenomenon that paint droplets are split into fine particles is called electrostatic atomization.
Under the action of high-voltage electrostatic field, various dielectric substances in the coating will appear positive and negative ion groups and positive and negative polymer groups, which move and gather in the direction of the anisotropic electrode. On the contrary, the paint droplet is split into two smaller particles, which is the cracking of the electrostatic field.
The electrostatic atomization process is done in the initial stage of the paint spraying out of the sharp edge of the muzzle or spray ring. The higher the voltage applied to the spray gun, the stronger the cracking effect of the electric field and the better the electrostatic atomization effect.
Most of the film-forming substances in coatings, that is, resins and pigments, are composed of polymer organic compounds, mostly non-conductive dielectrics. In addition to film-forming substances, solvent-based coatings also include organic solvents, cosolvents, curing agents, and electrostatic dilution. In addition to benzene, xylene, solvent gasoline, etc., most of these solvent-based substances are polar substances, with low resistivity and certain conductivity, which can improve the conductivity of coatings.
The molecular structure of dielectrics can be divided into polar molecules and non-polar molecules. The dielectric composed of polar molecules exhibits electrical properties under the action of an external electric field; the dielectric composed of non-polar molecules exhibits electric properties under the action of an external electric field, thereby generating an affinity for foreign heteroelectric charges, making the dielectric Its outer surface can be locally charged in an applied electric field.
The paint is sprayed out after being atomized by the nozzle. The atomized paint particles pass through the pole needle of the spray gun mouth or the edge of the spray disc and the spray ring due to contact and electrification. Surface charge density. The negatively charged paint particles move to the workpiece surface of opposite polarity under the action of static electricity, and are deposited on the workpiece surface to form a uniform coating film.