To achieve the matting effect of the matting powder, it is necessary to cause diffuse reflection of light on the surface of the paint film, otherwise the matting effect is not good. Therefore, do not grind the matting powder as much as possible. If grinding or dispersing at high speed for a long time, the surface of the matting powder will be damaged, and the particle size will become too small. This matting effect is not ideal. It will be larger than 30 microns, which is enough for general topcoats. The reason why the matting powder is generally not ground is the sponge-like structure of the matting powder itself. Excessive grinding (or dispersion) will destroy the sponge-like structure and form a smooth cut surface. As a result, the extinction efficiency is reduced. When the matting powder is ground, the matting ability will be affected. Generally, the particle size of the matting powder is 5-20um, which will not affect the surface. If there is any effect, the steps of adding (adding while stirring) and the viscosity of the paint can be Appropriately low, unless the dispersing power of the matting powder is poor, otherwise the dispersion will meet the requirements of 15-30 minutes.

In addition, sometimes the dispersion fineness can meet the requirements in the laboratory, but the fineness problem will occur in actual production. The main reason is that the laboratory shearing force is high, but the dispersing machine used in actual production has insufficient shearing force.