PVC plastisols are used for underbody protection and for seam-sealing in the automotive industry. HDK^® pyrogenic silica can optimally adjust the rheology and thus prevent the plastisols from dripping and sagging.

Polar binder systems, for example, based on polyurethane or epoxy resin systems, can be rendered permanently thixotropic with appropriate hydrophobic HDK^®grades. Hydrophobic HDK^® is used in car-window installation to adjust the rheological properties of the adhesives.