Adding ultrafine silica, talcum powder and other fillers can obviously reduce the luster, especially the particle size of the fillers has a great influence on the luster of the coating film.And the larger the particle size, the lower the luster.Therefore, it is necessary to pay attention to increase the amount of filler, otherwise it will make the film flat and mechanical strength.In epoxy powder coating, the influence of calcium carbonate particle size on the gloss of coating is shown in the table.Matt coatings can be obtained by adding ultrafine silica and kaolin to acrylic and polyester powder coatings.In addition, wax such as polyethylene paraffin and hydrogenated castor oil can also be used to obtain matt coatings.Pigment extinction principle and application: physical pigments, such as diatomite, kaolin, silica, etc., are functional fine materials specially used as extinction agents, which belong to inorganic filler type.When the film is dry, the tiny particles will form a slightly rough surface on the film surface, reducing the reflection of light and thus obtaining a dull appearance.And the extinction effect of this kind of extinction agent is restricted by many factors.Take silica as an example. When it is used as a matting agent, the matting effect will be affected by such factors as pore volume, average particle size and particle size distribution, dry film thickness and whether the surface of the particles has been treated or not.It is proved that silica with larger pore volume, uniform particle size distribution and matching dry film thickness has better extinction performance.