Use of organopolysiloxanes in the manufacture of paper-coated plaster boards

摘要

Use of an organopolysiloxane having the formula ##STR1## in which R. sup.1 is an alkyl or aryl radical, at least 80% of the R.sup.1 radicals being alkyl radicals,PPR.sup.2 is an alkyl radical or the R.sup.4 Z radical, at least 2/3 of the R.sup.2 radicals being R.sup.4 Z radicals, in whichPPR.sup.4 is a difunctional hydrocarbon radical,PPZ is --NH.sub.2, -- NH(CH.sub.2).sub.c --NH.sub. 2, --NH(CH.sub.2).sub.c NH(CH.sub.2).sub.c NH.sub.2, in which c is 2, 3, - -NHCONH.sub.2 radical, --SH, --S.sub.4 -- R.sup.4 --Si(OR.sup.3).sub.3, -- P(C.sub.6 H.sub.5).sub.2 or ##STR2## R. sup.3 is an alkyl radical with 1 to 4 carbon atoms, or a hydrogen radical, PPa is not less than 4,PPb/a is not less than 0.001, but not greater than 0.5, andPPx is not less than 0.1, but not greater than 2, PPas a material for decreasing the water absorption of paper which is intended to be used for coating plaster paste in the manufacture of paper-laminated plaster boards. The organosilicon compounds cure without the use of special catalysts. Their aqueous preparations exhibit high stability at use concentrations and are independent of the pH of the paper. The water absorption of papers which are free of aluminum sulfate can also be reduced.