Industry News

What is Metal Powder Coating?

2022-02-17
Metal powder coatings refer to various powder coatings containing metal pigments (such as copper gold powder, silver aluminum powder or mica powder, etc.) Spraying of indoor and outdoor objects.

In terms of manufacturing process, the current domestic market mainly adopts the dry mixing method. As the name suggests, dry mixing is to directly mix metallic pigments and other raw materials together. This kind of dry mixed metal powder is extremely unstable, and the sprayed effect will have yin and yang surfaces ( From different angles, the coating on the same place will have obvious color difference).

The bonding technology of metal powder coating is composed of dry mixing method and heat treatment method. The powder coating base powder is added to a high-speed mixer with a temperature-controlled jacket, and the high-speed rotation of the machine is used to generate friction in a short time due to the different moving speeds between the stirring paddle and the material to be mixed, and the base material mixture is heated by friction. temperature rises.

This temperature value is slightly lower than the glass transition temperature (Tg) of the resin. Under nitrogen protection and mechanical high-speed stirring, the metal pigment is quickly added to the high-speed rotating powder to make it bond to the softened powder coating particles. On the surface, and then quickly discharge the material to cool, this is the bonding technology of powder coating.

After the metal effect powder coating of Bonding is made, the application of electrostatic spraying shows that the advent of the bonding process has brought confidence to the powder coating manufacturer to provide metal flash paint.

One of the biggest advantages of using bonding technology is that it produces a brighter finish, some powder coatings have metallic effects that approach or exceed liquid paints. The process also allows us to make better use of various pigments.

Powder coating is a good coating product, it has the ability to agglomerate at temperature, and the resin and leveling agent in powder coating will soften when heated, which will cause it to have a tendency to agglomerate. This powder coating is an organic high molecular polymer.

When the powder coating is sprayed, the input air pressure should not be too large, and it is generally better to control it at 0.5-1.5kg/cm2. Too much air pressure will cause poor pattern definition or some pitting. The electrostatic voltage should not be too high, generally controlled at around 60-70Kv.

If the voltage is too high, the powder attached to the surface of the workpiece will rebound and cause pitting. Disadvantages such as poor leveling. When spraying powder, care should be taken to ensure the thickness of the coating film. The spraying process, also known as powder coating, is a new type of coating process developed in recent decades, and the raw material used is plastic powder. The powder coating does not contain solvents and is pollution-free. High efficiency, suitable for automatic assembly line coating, high powder utilization rate, and recyclable.