Fumed silica is an amorphous silica product obtained by hydrolysis of organohalogen silanes in a hydrogen-oxygen flame at high temperature. Extremely high, the silica content is not less than 99.8%. Fumed silica has been produced industrially since the 1940s. In the past decades of industrial production, no cases of silicosis caused by inhalation of fumed silica have been found. The International Association for Cancer Research (IARC) stated that there is not enough evidence to prove that synthetic amorphous silica is carcinogenic to humans or experimental animals. On the contrary, IARC has listed crystalline silica as a carcinogen. The body's directive document (67/548/EEC) also pointed out that amorphous silica is not a dangerous substance. Because of its good stability, physiological inertia, thickening properties, etc., it can be widely used in the field of daily necessities.
 
Fumed silica is a very important and very effective additive in body care products, adding a small amount can have a significant effect. Since there are many hydroxyl groups on the surface of fumed silica, the interaction between particles is relatively strong. In the liquid system, highly dispersed fumed silica can easily interact in the system to form a three-dimensional network, making the viscosity of the system increase, it can effectively prevent the flow of the system when it is still, and when the appropriate shear force is applied, the three-dimensional network is destroyed, so that the system has a liquid flow shape, and when the shear force is eliminated, the network can be re-formed , so that the system can form a "gel" again. Therefore, it can act as a thixotrope and thickener in gel or paste products such as toothpaste, sunscreen, facial mask, etc. The dosage is generally 1-3%, and some are as high as 4-8%. However, in pearlescent nail polish or spray-type care products, fumed silica mainly plays a suspending role, so that various components in it can be evenly dispersed in the system, preventing sedimentation and increasing the storage stability of the system. Fumed silica is also widely used in hair care products. For example, anti-dandruff shampoos contain some active ingredients such as selenium sulfide, salicylic acid, sulfur, zinc compounds, etc. Most of these ingredients need to form a good dispersion and suspension in the system, which can be satisfied by adding fumed white carbon black. Require. Water-in-oil products generally have a greasy feeling. After adding fumed silica, it can reduce the greasy and sticky feeling. In oil-in-water products, fumed silica can improve the temperature and pH stability of the product. In sunscreen oil, adding surface-treated fumed silica can not only improve the texture, but also improve its water resistance. The general dosage is 0.5-3%. Surface-treated fumed silica can improve the moisture resistance of creams and gels, which is very beneficial for lipsticks, eyebrow oils, cosmetics, whitening creams and sunscreens.