Compared with ordinary spray paint, electrostatic spraying paint is different from the paint used by ordinary spraying method in some properties except for equipment. Generally speaking, electrostatic sprayed paint needs to have the following characteristics:
①The fluidity and adhesion are better;
②The fineness should be high, and the brightness should be good;
③Have certain electrical conductivity;
④The solid content of the paint should be high, and the hiding power should be good; ⑤The viscosity should be proper. With the above factors, the main reason is to make the paint easy to charge and atomize well in the electric field. Therefore, it must have low electrical resistance and surface tension. The flash point should be high. Generally, the resistance of electrostatic spray paint is controlled at 10-50 megohms. In order to achieve this goal, the general high-resistance paint needs to be adjusted by adding a solvent with high boiling point, strong solubility and high polarity, while reducing its surface tension and improving the flash point. High-polarity solvents are the easiest to charge, which can effectively increase the resistance of paint. The solvent with high boiling point is not easy to volatilize during atomization, which can prevent "orange peel" on the surface of the paint film. The surface tension of the solvent should be small to enhance the #effect. The high flash point is less prone to fire.
In addition, electrostatic spray paint requires low viscosity and high solid content. The fineness is higher than that of ordinary paint, so it can increase the gloss of the paint film. The specific gravity of the pigment should not be too large, otherwise it will sink to the bottom and cause the color of the paint film to be inconsistent.
Resin is the main film-forming substance. Various resins and solvents have different charging capabilities, and their adaptability to electrostatic spraying is also different. For example, the conductivity of melamine formaldehyde resin is better, followed by alkyd resin, and epoxy resin is worse.
At present, the electrostatic spray paints that have been used in China include nitro, perfluoroethylene, amine, drunk acid, asphalt paint and other varieties.
Compared with ordinary spray paint, electrostatic spray paint has the following main features:.
1. Paint particles are negatively charged particles, which are attracted to the workpiece (anode) under the action of mutual repulsion. The paint film produced in this way is uniform and complete, with good adhesion and strong abrasion resistance. Improve the quality of the paint film.
2. It can realize the continuity of the painting process, improve labor productivity, increase work efficiency by 10-100% compared with ordinary painting, and improve working conditions.
3. Paint mist seldom scatters, it can save more than 10-50% of paint than manual spraying, and the paint utilization rate can reach more than 95%.
4. Electrostatic spray paint can realize spraying automation, remote operation, reduce labor intensity, and paint mist is rarely scattered, which improves labor and hygiene conditions.
The difference between electrostatic spraying and general spraying.
This construction method is also mostly matched with electrophoretic coating. The primer is applied by electrophoresis and the topcoat is electrostatically sprayed to realize the continuity and automation of the painting operation. The mature example of this kind of supporting construction is the flow operation of electrophoretic coating primer of bicycle paint and electrostatic spraying topcoat.
