Electrophoretic paint

Electrophoretic coating is a coating method that uses an external electric field to make the pigments and resin particles suspended in the electrophoretic liquid migrate in a directional manner and deposit on the substrate surface of one of the electrodes. In this process, the workpiece (i.e., the object to be coated) is immersed in the anode or cathode electrophoretic paint tank liquid. At this time, the charged paint particles will rush to the workpiece under the action of the electric field and then settle on the workpiece. In this way, a continuous and dense paint film with a thickness that meets the standard requirements can be formed on the surface of the workpiece, thereby achieving the purpose of spraying.

1. Electrophoretic paint and applicable industries (workpieces)

In the electrophoretic process, special electrophoretic paint is needed. Electrophoretic paint is an organic coating, mainly composed of additives, resins and pigments, and its main solution is a small amount of organic solvents and water. Electrophoretic paint can be roughly divided into two categories: epoxy electrophoretic paint and acrylic and polyurethane electrophoretic paint. The former is mainly used in large industrial enterprises, with high requirements for corrosion and rust resistance. It has various colors such as black, gray, red, and yellow. It is mainly used in the automotive industry, bicycle industry, motorcycle industry, home appliance industry, etc. The electrophoretic paint film is opaque. The latter is mainly for decorative workpieces, light industrial products that require beautiful appearance and less corrosion resistance, such as glasses, lighters, locks, lamps, stationery, stationery and hairpins, and this electrophoretic paint film is transparent. When matched with various color pastes, it can achieve colorful and bright effects in various electroplating processes.

2. Examples of the advantages of electrophoretic paint coating

The electrophoretic paint film has the advantages of full, uniform, flat and smooth coating. The hardness, adhesion, corrosion resistance, impact performance and penetration performance of the electrophoretic paint film are significantly better than other coating processes. It uses water-soluble paint and water as the dissolving medium, which saves a lot of organic solvents, greatly reduces air pollution and environmental hazards, is safe and hygienic, and avoids the hidden danger of fire. The coating efficiency is high, the coating loss is small, and the coating utilization rate can reach 90% to 95%; the coating film thickness is uniform, the adhesion is strong, the coating quality is good, and all parts of the workpiece, such as the inner layer, depressions, welds, etc., can obtain a uniform and smooth paint film, which solves the coating problem of other coating methods for complex-shaped workpieces; the production efficiency is high, the construction can realize automated continuous production, and greatly improve labor efficiency.

3. Main process and main process equipment of electrophoresis technology

The electrophoretic coating process generally consists of four main processes: pre-treatment before coating, electrophoretic coating, post-electrophoretic cleaning, and drying of the electrophoretic coating film. The main equipment includes:

(1) tank body

(2) stirring circulation system

(3) electrode device

(4) paint liquid temperature control device

(5) paint supply device

(6) ultrafiltration device

(7) ventilation device

(8) power supply device

(9) post-electrophoretic water washing device

(10) paint storage device