At present, the pigments suitable for powder coatings can be divided into four categories: color pigments, metallic pigments, functional pigments, and extender pigments according to their properties and uses.
In addition to imparting various colors to powder coatings, pigments can also improve the relative mechanical properties of powder coatings and reduce costs. In the process of use, the requirements of powder coatings for pigments are: the pigments do not react during the preparation, storage, transportation and use of powder coatings; the pigments must be stable and not affected by air, humidity and the environment; in terms of coloring, The pigment’s dispersibility, tinting power, hiding power and temperature resistance are required. Normally, the best dispersion particle size is 0.2～0.7μm, and the temperature resistance should be above 180℃, because the general powder coating is baked at 180～ 200℃; the pigment should have excellent light and weather resistance, especially in weather-resistant powder coatings, the light resistance should be 7-8 grades, and the weather resistance should reach 5 or more; finally, the oil absorption of the pigments should be moderate , Impermeability is better; in addition, it is best not to use toxic pigments, such as lead, cadmium, chromium toxic metal pigments. The properties of iron oxide pigments basically meet the characteristics described above, and they have great potential for use in powder coatings. Faced with the problem of poor color vividness of iron oxide pigments, organic pigments and iron oxide pigments are usually mixed to color to achieve the desired hue.
