Pigment of Coatings

The paint film of the paint composed only of film-forming substances is transparent, and the protective effect on the substrate and the decorative effect are poor. For this, pigments are added. Pigment is a water-insoluble, fine powder colored substance that can be evenly distributed in the medium. Its function is to increase the covering property of the paint film, increase the strength of the paint film, aging resistance, and some special functions (such as inhibiting metal corrosion) , prevent ultraviolet rays from penetrating, high temperature resistance, etc.).

1. Requirements for pigments

Good tinting strength, high dispersion, bright colors.

2. Pigment classification

According to the chemical composition, it can be divided into two categories: organic pigments and inorganic pigments. According to their function in coatings, they can be divided into three categories: coloring pigments, antirust pigments, and extender pigments (related instruments: Colorimeter, Color Chart, etc.).

1) Coloring pigment is one of the most varieties of pigments. Its function is to color and cover the surface. Commonly used varieties are:

Iron red, titanium dioxide, lithopone, toluidine red, lead chrome yellow, iron blue, phthalocyanine blue, lead chrome green, phthalocyanine green, carbon black, aluminum powder (silver powder), copper powder (gold powder), etc. The colors are red, white, yellow, blue, green, black and metallic luster.

2) The function of the extender pigment is to fill the paint to increase the thickness of the paint film, improve the wear resistance of the paint film (related instruments: wear-resistant testing machine) and durability.

The main varieties are; talcum powder, magnetite, barium sulfate, calcium carbonate, mica powder, diatomaceous earth and so on.

3) The main function of anti-rust pigment is to prevent metal from rusting. The main varieties are: red lead, zinc chrome yellow, iron oxide red, aluminum powder, barium metaborate, etc.