Potassium methylsiliconate

Potassium methylsiliconate (CAS 31795-24-1, EC 250-807-9) is an organosilicon compound supplied as an aqueous potassium salt solution. It is commercially available under trade names including BS 15, Penta 811, Penta 811K, and the shorthand designations 51T and T 51. It carries no assigned E-code.

In building and construction, it penetrates mineral substrates such as concrete and masonry, where it reacts with atmospheric CO2 to form a hydrophobic silicone resin network that reduces water ingress without blocking vapour transmission. In textile and paper treatment, it bonds to cellulosic fibres to impart durable water repellency and modify surface friction characteristics.

Potassium methylsiliconate is supplied in aqueous solution at varying active-matter concentrations. It is subject to REACH registration requirements within the EU. Packaging is typically in drums or intermediate bulk containers; buyers should confirm available concentrations and packaging formats directly with the supplier.