| abstract |
The invention relates to a hydrophobicizing agent for gypsum-plaster-bound construction materials comprising a substrate based on pulverulent organic or inorganic solids with a BET surface area >5 g/m2 and comprising one or more organopolysiloxanes having Si-bonded hydrogen (organohydropolysiloxanes) built up from units of the general formula HaSiR1bO(4-a-b)/2, where the radicals R1 are identical or different monovalent hydrocarbon or hydrocarbonoxy radicals having from one to 15 carbon atoms, or are hydroxyl groups, with the proviso that at least one Si-bonded hydrogen atom per molecule is present, and a takes values from 0 to 3, and b takes values from 0 to 3. |