Fumed silica (CAS number 112945-52-5), also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles. The resulting powder has an extremely low bulk density and high surface area. Its three-dimensional structure results in viscosity-increasing, thixotropic behavior when used as a thickener or reinforcing filler. Fumed silica has a very strong thickening effect. Primary particle size is 550 nm. The particles are non-porous and have a surface area of 50600 m2/g. The density is 160190 kg/m3. APPLICATION Paints and coatings Unsaturated polyester resins, laminating resins and gel coats HTV- and RTV-2K-silicone rubber Adhesives and sealants Printing inks Cable compounds and cable gels Plant protection Adhesives and sealants Chemical mechanical planarization (CMP) Coatings Composites Food additives Greases Pharmaceuticals Printing and packaging Silicone sealants Skin and beauty care product