Wacker HDK H18 Fumed silica Wacker Rheology Modifiers / Thickeners >> Mineral >> Fumed Silica Epoxy (EP) Silicones (Si) PU - Prepolymers ADHESIVE Hydrophobic WACKER HDK® is produced by the chemical reaction of hydrophilic WACKER HDK® with reactive silanes, e.g. chlorosilanes or hexamethyldisilazane. Hydrophobic fumed silica is water-repellent and does not disperse in water. Hydrophobic WACKER HDK® is used as an active filler in silicone elastomers, as a thixotropic agent in coatings, printing inks, adhesives, as well as in polar epoxy, vinyl ester or polyurethane resins. One of the most important properties of WACKER HDK® is its ability to increase viscosity and provide thixotropic effects. WACKER HDK® H18 Pyrogenic silica - Fumed Silica Synthetic, hydrophobic amorphous silica, produced via flame hydrolysis White colloidal powder of high purity WACKER HDK ® H18 is applied as thickening and thixotropic agent in composites, coatings and adhesives, especially in vinylester, epoxi and polyurethane systems. High purity, synthetic, hydrophobic amorphous silica. Used as a thickening and thixotropic agent in adhesives especially in vinylester, epoxi and polyurethane systems. Offers water-repellency.