The Munich-based WACKER Chemical Group will present a new fumed silica called HDK® H21 for the first time at the European Coatings Show 2019. This product was developed by WACKER to regulate the flow of polar adhesive systems. This fumed silica is extremely hydrophobic, but can be mixed with polar adhesives quickly and efficiently. HDK® H21 has excellent rheological properties in epoxide-based, vinyl ester-based and polyurethane-based adhesives and can be used to formulate anti-sag products, including structural adhesives for many industrial applications. The European Coatings Show (ECS) will be held from March 19 to 21, 2019 in Nuremberg, Germany.
Adhesives formulated with HDK® H21: The Munich-based WACKER Chemical Group is demonstrating this new fumed silica product for the first time at the European Coatings Show 2019. It is a product developed by WACKER specifically for the production of anti-sagging industrial adhesives. (Photo: WACKER)
HDK® brand fumed silica is a white amorphous powder, which is high purity silica with low density. HDK® H21, a fumed silica product that WACKER will present at the European Coatings Show, also has these properties. The product has a large specific surface area. Although this product is very hydrophobic and non-polar, it can mix with polar liquids quickly compared to other hydrophobic fumed silica products.
WACKER laboratory test results show that HDK® H21 mixes with adhesive formulations significantly faster than other hydrophobic products. Especially in polar systems, this product has excellent rheological properties and stronger efficacy than other hydrophobic fumed silicas. Therefore, using HDK® H21 for the production of highly efficient adhesives can save time and effort. In addition, the product can be used to formulate products with extremely strong anti-sagging properties.
Industrial adhesives formulated with WACKER's fumed silica HDK® H21 are extremely resistant to sags and will not flow even when the adhesive is applied to inclined or curved surfaces. (Photo: WACKER)
Due to its large specific surface area and its hydrophobicity, HDK® H21 can impart excellent shear thinning properties to polar fluids: depending on the amount used, this fumed silica can make the adhesive sticky and anti-sagging at rest. Under the action of shear force, it can become thinner. With this new additive, polar industrial adhesives can be pumped and applied without difficulty. If properly formulated with HDK® H21, adhesives on inclined or curved surfaces will not flow, even if the coating is thick, until fully cured.
The above-mentioned properties of HDK® H21 allow the adhesive to be applied quickly and achieve repeatable and flawless bonding. In addition, the product can extend the shelf life of the active components of the adhesive, prevent filler deposition, and because of its hydrophobicity, the fumed silica will not interact with the adhesive matrix.
HDK® H21 is an ideal rheological additive for high-strength industrial adhesives; this type of adhesive can be used to bond rotor blade halves of wind turbines and automotive parts, and it can also be used as a chemical anchor in the construction industry.