Use of organopolysiloxanes in the manufacture of paper-covered gypsum board

摘要

Use of organopolysiloxanes of the general formula IMAGE where R¹ is an alkyl or aryl radical, but at least 80% of the radicals R¹ are alkyl radicals, R² is an alkyl radical or the radical R 4 Z, but at least 2/3 of the radicals R² R 4 are Z radicals and where R 4 is a divalent hydrocarbon radical and Z is the radical -NH2, -NH (CH2) c-NH2, -NH (CH2) cNH (CH2) cNH2, -NHCONH2, where c = 2 or 3, -SH, -S4-R 4 -Si (OR³) 3, -P (C6H5) 2, IMAGE, R³ is an alkyl radical with 1 to 4 carbon atoms or a hydrogen radical, a = 4 , (b / a) = 0.001, but = 0.5, x = 0.1 but = 2, as a means of reducing the water absorption of paper used to cover gypsum pulp in the manufacture of paper-clad paper Gypsum board is intended. The organosilicon compounds cure without the use of special catalysts. Their aqueous preparations show high stability in use concentration and are independent of the pH of the paper. The water absorption of papers which are free of aluminum sulfate can also be reduced.