I. Advantages and disadvantages of dedusting

1. Dedusting and painting

Compared with painting, electrostatic powder spraying does not require thinner, non-toxic, no environmental pollution, good coating quality, high adhesion and mechanical strength, corrosion resistance, short curing time, no primer, low technical requirements for workers, and high powder recovery rate. The usage rate is high, but the decorative property is slightly worse than that of paint.

Spray paint is mixed with solvent (or hardener), applied after being atomized by compressed air or electrostatic force, and then flew to the workpiece and attached. The solvent volatilizes (or reacts with each other) and solidifies to form a film; High content of VOC (volatile organic gas) is more harmful to human health; The utilization rate of paint is very low, only about 50%; The film thickness formed by one spraying is 15~25um

The powder sprayed coating is in a fine powder state and attached to the workpiece by electrostatic action. When passing through the high-temperature oven, the coating is melted, leveled and cross-linked; VOC content is zero, but pay attention to the harm of dust; The paint can be recycled, and the utilization rate can reach more than 99%; The curing time is shorter than that of paint spraying, and the flowing phenomenon often occurs in the painted parts will not occur. Large equipment investment; It is applicable to the coating of thick film coatings, with a coating thickness of 50~150um;

2. Anti corrosion principle of powder spraying

After the metal surface coating is dried (solidified), the metal surface is isolated from the environment. However, the coating cannot prevent or slow down the corrosion process, because the polymer has certain water permeability, and the average pore diameter in its structure is 10-5~10-7cm, while the diameter of water and oxygen molecules is usually only 10-6~10-8cm. In order to improve the impermeability of the coating, the film forming material with low permeability and solid filler with high shielding shall be selected for the coating to make the coating reach a certain thickness, uniform, dense and impermeable. Porous.