A New Approach for Self-Cleaning Silicone-based Facade Coatings

Since being introduced in 1963, silicone resin emulsion paint (SREP) has developed into one of the most modern facade coating systems. While specific formulations and raw materials have changed in the last 42 years, the long-lasting performance properties resulting from the unique combination of water repellency, vapour permeability, low VOC and the silicon-resin based structure have remained consistent. A general characteristic of mineral construction materials is their porous structure. Because these structures readily absorb water, exterior walls are quickly discolored or damaged by rain. This drawback makes facade protection essential. With the growing use of insulating masonry and lightweight plasters, a water-vapour permeable finish is a key requirement, since, in a well-protected facade, any absorbed moisture must be able to escape to the atmosphere. The masonry protection features must also last as long as possible. Finally, a facade coating that protects the outer wall against water or environmental or chemical attack must also have an attractive appearance. Under certain circumstances or certain local environmental conditions it may be required to install a facade coating with furthermost reduced dirt pick-up. As the most recent development in this area the properties of tailor-made silicone-resin emulsion paints with convincing self-cleaning properties will be presented. A. Hausberger and H. Geich