“Manufacturers of gypsum construction materials need water repellents that are suitable for use in dry-mix processes, are exceptionally efficient and pose no problems when mixed with water,” explains Dr. Rudolf Hager, who heads the Construction Chemicals business team. “SILRES® BS Powder S is not subject to any of the problems associated with conventional powder-form gypsum hydrophobizing agents. It consists only of the pure active ingredient, without any carriers or encapsulation material, and is therefore extremely efficient.”
Patented SILRES® BS Powder S consists of potassium methylsiliconate, a material that has been used in building protection since the 1950s, for example for surface hydrophobizing of coarse ceramic clay products, or for integral water-repellent treatment of prefabricated gypsum elements. Up to now, however, alkali alkyl siliconates – as indicated earlier – have only been produced and used in the form of aqueous solutions.
“With the development of alkali alkylsiliconates, which can be obtained as free-flowing solids on an industrial scale, we have made a major breakthrough,” explains Rudolf Hager. WACKER has developed a variety of drying processes for making powders with different properties.
“We were also able to adjust the potassium-silicon ratio so as to optimize the balance between stability, reactivity and pH in gypsum-based construction materials.”