AEROSIL® fumed silica for skin and oral care
Cosmetic oils can be readily transformed to highly viscous gels with AEROSIL® fumed silica. This produces largely transparent products with a markedly pseudoplastic flow behavior. Particularly high viscosities are achieved with and AEROSIL® 200 and AEROSIL® 300. Hydrophobic AEROSIL® types, such as AEROSIL® R 972, AEROSIL® R 974, and AEROSIL® R 812, do not thicken as much but may be better suited to some types of oils and for use in emulsions. Depending on the desired rheologic behavior and the dispersing conditions, AEROSIL® fumed silica is typically used in concentrations ranging from 2.0 to 10 percent w/w.
Our product AEROSIL® 200 has a proven track record for toothpaste thickening efficiency. It will give your toothpaste the rheological body for good filling during manufacturing and easy handling by the consumer. 3-5 percent of high performance AEROSIL® 200 fumed silica, you will obtain the thickness you are looking for. With its very low iron content AEROSIL® 200 is well-suited for thickening peroxide toothpaste.
Cold manufacture of emulsions
Hydrophobic AEROSIL® types are especially suitable for increasing the viscosity of w/o (water-in-oil) emulsions and producing pseudoplastic flow behavior. AEROSIL® fumed silica can also be used more readily than other viscosity adjusters (e.g. waxes, layer silicates). Another advantage of formulations formulated with fumed silica is their low sensitivity to temperature, electrolytes and pH.
AEROSIL® fumed silica can effectively stabilize emulsions and help reduce the surfactant content. The finely divided AEROSIL® particles are enriched in the interphase between water and oil (Pickering emulsions), thereby preventing the disperse phases from coalescing. AEROSIL® R 816 is particularly suitable for this application.
Dry formula—high water resistance
Depending on the application, AEROSIL® fumed silica is used in a concentration range of 0.5 to max. 10 percent w/w. Particularly at concentrations over 3.0 percent w/w, it can cause a dry skin feel and counteract the oily or greasy skin feel of a formulation. The addition of hydrophobic AEROSIL® grades also considerably increases the water resistance of creams and lotions.
The effects described in the section "emulsions" can also be applied to sunscreen formulations. Besides improving storage and temperature stability, hydrophobic AEROSIL® fumed silica can improve water resistance in particular—a necessary feature of modern sunscreens. In addition, hydrophobic AEROSIL® grades can produce a more homogeneous distribution of physical and chemical UV filters, raising the sun protection factor.