Ready for Africa - Wacker Chemie AG


Ready for Africa

Cape Town’s commercial center: African architects often work with more vibrant colors than their counterparts in Europe or North America.

“Exterior walls are made with all kinds of building materials, such as natural stone, concrete and bricks. Each of these mineral-based materials responds differently to weathering and environmental factors,” explains Christian Putz, a paint systems engineer at WACKER in Burghausen. “Yet, for all of them, silicone resin emulsion paints provide the most effective protection,” he stresses.

When it comes to the ingredients that are needed to make up the proper paint formulation, this WACKER expert knows his stuff. He used his knowledge to help the Kenyan paint maker develop the optimum recipe for the regional market. “The ingredients and the mixing ratios are crucial to the end result,” says Putz. However, all the recipes have one thing in common: they contain a silicone resin binder. “Silicone resin emulsion paints dry to form a microporous film that allows high water-vapor permeability while protecting the wall against liquid water,” explains Putz. In the process, the silicone-resin binder forms a network structure, and we therefore use the term “silicone resin network.” The backbone is a stable silicon-oxygen chain, while organic groups, like little umbrellas, are responsible for the water repellency – giving the paint its hydrophobic and weathering-resistant properties.

Ideal Properties

Breathable yet water-repellent – it is this combination which makes the silicone resin network so effective. Moisture collecting behind the coating can thereby easily escape to the outside. As a result, this high-quality moisture protection even works on slightly defective surfaces, e.g. with cracks. “And the hydrophobic layer provides an attractive visual effect, so-called beading,” says Hock. The water droplets roll off the treated surface easily and freely. As they do so, they wash away dirt and microorganisms – ensuring that the exterior walls and masonry retain their good looks for much longer.

At the same time, the walls are color fast. “Silicone resins even resist dilute alkalis and acid rain as well as the ultraviolet and infrared components of sunlight,” adds Putz. “All these properties are the reason why silicone resin emulsion paints are longer lasting than other coating systems,” he notes.