HDK pyrogenic silicas are white, amorphous powders of low density and large specific surface area. This high surface-area-to-mass ratio is responsible for the outstanding rheology effect of HDK® products. At the European Coatings Show 2017, WACKER will present four HDK® grades for advanced paint, coating and adhesive applications.
The hydrophobic HDK H30RM and HDK H30LM grades feature high specific surface areas and silane modification with pronounced water repellency, which is greater in HDK H30RM. The two products are particularly suitable for binder systems of high polarity, whereby more pronounced rheology effects can be achieved with HDK® H30RM. Both grades exhibit excellent transparency in clear coats. Furthermore, they are entirely free of polydimethylsiloxane (PDMS) and thus enable crater-free surfaces during coating application. Accordingly, their main applications include surface coatings for the automotive industry and high-quality industrial paints.
HDK H30RY is a hydrophobic, methacrylic-functional silica. The reactive product can be chemically incorporated into resin networks, enhancing mechanical properties of systems based on vinyl esters, polyesters or acrylates. This yields a broad range of applications – from coatings and adhesives to sealants. Moreover, the properties of dental fillings and nail gels can be optimized with HDK H30RY.
HDK H20RH is a hydrophobic silica that has been treated with alkylsilane. The silicone-fluid-free additive features exceptional rheological activity in polar systems and prolongs the shelf life, even at high pH values. It is thus suitable for use in amine hardeners of two-component adhesives. Further application fields include automotive adhesives, half-shell bonding in wind turbines, and chemical anchors. In addition, HDK® H20RH can give jointing compounds favorable pull-off characteristics. It also features good wetting properties. Products formulated with this silica can thus generally be painted over very well after curing.