There are generally two conditions for the formation of small unevenness on the surface of the coating: one is that there is a sufficient amount of matting agent particles with a suitable size in the wet film. The second is the volume shrinkage of the coating film during drying or curing. One condition cannot be fully satisfied, and the matting effect is not ideal.
Traditional solvent-based coatings have a volatile content between 30% and 80%. During the drying or curing process, as the volatiles evaporate, the coating film shrinks significantly and matting is easier; water-based coatings use water as a dispersant to dry Or during the curing process, due to the evaporation of water, the coating film shrinks significantly, and the matting is not difficult. However, for high-solid coatings, the solid content is generally 70%-90%, and the difficulty of matting is relatively increased; UV light curing coatings have a solid content of 100%, curing shrinkage is less than 10%, and it is difficult to matte; and powder coatings are not organic Volatile, 100% solid content, most difficult to extinction. For these coatings, during the drying or curing process, the coating film shrinks little or not. Therefore, it is necessary to form tiny irregularities on the surface of the coating, and use a matting agent for matting.
The matting agent for coatings must have the following characteristics: high chemical inertness, does not react with any components in the coating film; little interference to the transparency of the coating film, little influence on the rheology of the coating; good matting performance, can be produced at a low amount Strong matting performance; in liquid coatings, good suspension, long-term storage, no hard precipitation; little impact on the mechanical and chemical properties of the coating film, easy to disperse, no pollution to the environment, and no harm to the human body.