Using alkylsilane hydrophobic gypsum moulds and methods for hydrophobic hydrophobic moulding of gypsum moulds

摘要

1. Shaped bodies formed of materials containing gypsum or gypsum as predominating component, which have been made hydrophobic by treatment with alkylsilanes, characterised in that their rendering hydrophobic is carried out with the aid of a mixture of alkalialuminate and silanols (ethyl, propyl or n-butyl) in aqueous or aqueous-alcoholic solution.