As a consequence of its large specific surface area and its hydrophobicity, HDK® H21 gives pronounced shear-thinning properties to polar liquids. A suitable amount of pyrogenic silica will make the compound viscous when at rest and prevent sagging. When shear forces are applied, however, the viscosity drops. As a result, a polar industrial adhesive containing the new additive can be readily pumped and precisely applied. When modified with the appropriate concentration of HDK® H21, adhesive compounds will not run until fully cured – not even when applied in very thick layers and when the bonding surface is sloping or curved.
In this way, HDK® H21 creates the conditions for efficient adhesive application and a reproducible, flawless bond. The product also enhances the shelf life of reactive adhesive components. It prevents fillers from settling and, due to its hydrophobic character, barely interacts with the adhesive matrix.
HDK® H21 is perfect for use as a rheological additive in high-strength industrial adhesives, such as those in automotive industry bonding applications, in chemical dowels for the construction industry, and in bonds between the half shells of wind turbine rotor blades.
New at ECS 2019: the WACKER Forum
WACKER will be devoting a total of 240 square meters of floor space to solutions for paints, coatings, construction and adhesives applications at the 2019 European Coatings Show. More than 70 experts will be on hand at Booth 1-510 in Hall 1 to discuss the products and their applications with interested parties. Making a new appearance this year will be the WACKER Forum, right beside the main booth. Here, 30-minute presentations aimed at an international specialist audience will be held on technology, trends and innovations under the motto “Let’s talk about...” More information about the program of presentations at the WACKER Forum can be found at
Visit WACKER at the European Coatings Show 2019 in Hall 1, Booth 1-510.