At the European Coatings Show (ECS), which took place in Nuremberg, Germany, on 4th to 6th April, WACKER presented pyrogenic silica grades for paint, coating and adhesive applications, sustainable silicone resins for new weathering- and heat-resistant coatings, a new dispersion for fireproof coatings, and a new binder for high-end digital printing inks.
Pyrogenic silica grades
Munich-based chemical group WACKER presented four specialty grades of HDK pyrogenic silica for paint, coating and adhesive applications.
Hydrophobic HDK H30RM and HDK H30LM are particularly suitable for rheology control in automotive clear coats. They exhibit excellent transparency in surface
coatings and are PDMS-free, so crater-free clear coats can be applied.
HDK H30RY can be chemically incorporated into resin networks and can improve mechanical properties of surface coatings and sealants.
HDK H20RH possesses excellent storage stability in basic systems and is ideal as a thickening agent in two-component adhesives and jointing compounds.
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.
Sustainable silicone resins
The new binder SILRES REN70-M is used in high-temperature coatings to ensure heat resistance up to 600°C. The product is almost entirely free of aromatic solvents (<0.1 %), providing a biodegradable alternative to conventional binders (which are typically supplied as a solution in aromatic solvents such as xylene). It is particularly suitable for formulating coatings for industrial equipment, engine parts or stoves.
SILRES REN70-M offers the ideal combination of hardness and flexibility. As a binder in heat-resistant coatings it effectively protects metal surfaces from corrosion even at high operating temperatures or rapid temperature fluctuations.
The binder dries tack-free even at room temperature. SILRES REN70-M can also be fully chemically cured, which takes place via reactive silanol groups. With the aid of a catalyst, complete chemical cure can be achieved in just 20 minutes at 180°C, which means the silicone resin cures faster than comparable products.
For weathering-resistant coatings, WACKER offered the new silicone intermediate SILRES IC 235, which contains no aromatic compounds at all. It is used in coatings for bridges, stators of wind turbines or industrial plants.
The new silicone resin has been designed so that an addition of only 15% is sufficient to improve the UV and weathering resistance of the organic binder in a coating system – without detracting from its mechanical properties. Weathering and lab tests have shown that SILRES IC 235 provides for substantially improved gloss retention, greater protection against weathering and an extended useful life. Additionally, a higher percentage of silicone in the binder improves the heat resistance of the coating system up to 300°C. SILRES IC 235 is used, for example, in coatings for static metal structures such as bridges or railings and in industrial plants.
Dispersion for fireproof coatings
WACKER's tradeshow offering for industrial coatings was rounded out with the polymer dispersion VINNAPAS EZ 3067 for special fire-resistant coatings.
Intumescent Coatings are special fire protection coatings that swell on steel girders to form a jacket that slows the rate at which load-bearing structural parts of a building melt or buckle in the event of fire. Applied in a thickness of just 1-4mm, the coating expands on exposure to heat, forming a layer of foam that is roughly 10-100 times the original coating thickness. As the foam has an extremely low thermal conductivity, the temperature inside the coating rises more slowly. The steel girder is protected from the heat for a set length of time and so remains structurally stable for longer.
The new VINNAPAS EZ 3067 polymer dispersion shows particularly vigorous foam development and expansion, and long-term foam stability. It also enhances the adhesion and strength of the coatings, ensuring that the protective layer adheres firmly to the substrate and acts as a heat barrier for a set time. Without the binder, the foam layer would be too brittle and would have inadequate adhesion to the steel substrate. The dispersion is water-based and free of organic solvents or additives such as plasticizers. If suitably formulated, such a highly fire-resistant coating can attain fire resistance classes as high as F120 (heat protection for up to 120 minutes).
Binder for digital printing inks
WACKER showcased its new low-viscosity binder VINNOL E 18/38 for high-end digital printing applications. The vinyl chloride-vinyl acetate-copolymer resin ensures excellent droplet formation in solvent-based ink-jet inks. This increases the print quality of the end product and extends the longevity of the print-head. VINNOL E 18/38 adheres well to flexible PVC and many other substrates. It is suitable for wide-format printing of advertising banners, as well as for cables, screw caps and many other plastic items.
‘Use by Dates’ are printed on the packaging of different consumer goods. Thanks to VINNOL E 18/38, the printing ink adheres to a wide variety of substrates. The binder is very resistant to a wide variety of liquids and it complies with numerous provisions for food contact (e.g. regulations issued by the US FDA; FDA 21 CFR Sections 175.300 and 175.105), making it suitable for food packaging inks.