4. Used as a matting agent

Due to the tiny particle size and the formed network structure, fumed silica has obvious light scattering ability. Therefore, fumed silica has good optical properties when used in varnishes, and has become the first choice for high-grade coating matting agents.

The main characteristic parameters affecting fumed silica matting agent are pore volume (porosity), average particle size and particle size distribution, surface treatment, etc. For a given fumed silica matting agent, its matting efficiency increases with increasing pore volume. The average particle size of fumed silica and its particle size distribution play an important role in the reduction of paint gloss. For a given coating and film thickness, the matting effect is best when the particle size of the matting agent corresponds to the dry film thickness of the coating. The narrower the frequency band of the particle size distribution, the higher the extinction efficiency.

5. Other application features

(1) After fumed silica is surface-treated with methyl acrylsilane, it can be added to the polyurethane coating to play a role in friction resistance.

(2) Fumed silica can also improve the weather resistance and scratch resistance of the coating, and improve the bonding strength between the coating and the substrate.

(3) Fumed silica has strong ultraviolet absorption and infrared light reflection characteristics, and it can improve the anti-aging performance of coatings when added to coatings.

To sum up, both current and future manufacturing is developing towards functionalization and greening, and environmentally friendly coatings and functional coatings have also emerged as the times require. The manufacture of fumed silica must also develop in the direction of functionalization and individualization. In order to exert the good performance of fumed silica, manufacturers should communicate closely with coating users, and fully consider key factors such as its dispersion and stability in coatings. At the same time, in the process of formula design, attention should be paid to the influence of the coating system on it.