Matting powder is a chemical agent that is easily dispersed and organically treated. It is a kind of coating additive. The main purpose of matting powder is to To reduce the gloss of the coating film, the commonly used matting powders include ultrafine silica, talc powder, aluminum stearate, calcium stearate, low molecular thermoplastic resin, etc. Matting is the use of certain methods to reduce the glossiness of the surface of the coating film. In today’s paint industry, people generally use the method of adding matting powder. There are mainly the following categories:
1. Wax
Wax is an earlier and widely used matting agent, which belongs to organic suspension matting powder. After the coating is finished, with the volatilization of the solvent, the wax in the coating film is precipitated, suspended on the surface of the coating film as fine crystals, forming a rough surface that scatters light and plays a matting role. The feature of wax as a matting agent is that it is easy to use, and it can give the coating film a good feel, water resistance, heat and humidity resistance, and stain resistance. However, after the wax layer is formed on the surface of the coating film, it will also prevent the volatilization of the solvent and the penetration of oxygen, which will affect the drying and recoating of the coating film. The future development trend is to use synthetic polymer wax and silica in combination to obtain the best matting effect.
2, metal soap
Metal soap is a matting agent commonly used by people in the early days. It is mainly some metal stearates, such as aluminum stearate, zinc stearate, hard Calcium stearate, magnesium stearate, etc. Among them, aluminum stearate is widely used. The extinction principle of metal soap is based on its incompatibility with the paint components. It is suspended in the paint with very fine particles, and is distributed on the surface of the paint film when it forms a film, which makes the surface of the paint film produce microscopic roughness and reduces the paint. The reflection of light on the surface of the film achieves the purpose of extinction.
3. Functional fine material
Extender pigments, such as diatomaceous earth, kaolin, fumed silica, etc., are functional fine materials specially used as matting agents, which belong to inorganic filling matting agents. When the coating film is dry, their tiny particles will form a micro-rough surface on the surface of the coating film, reducing the reflection of light and obtaining a matte appearance. The matting effect of this type of matting agent is restricted by many factors.
In addition to the above three commonly used matting agents, some drying oils, such as tung oil, can also be used as matting agents in paints. It mainly uses the high reactivity of the conjugated double bond in tung oil to make the different oxidation cross-linking speeds on the bottom surface of the coating film to make the surface of the coating film uneven and achieve the matting effect.
微信扫一扫打赏
