The invention describes novel organosilicon compounds containing oligoisobutylene or polyisobutylene groups and comprising at least one unit of the formulaA.sub.a R.sub.b SiX.sub.c O.sub.4-(a+b+c)/2, (I)where R are identical or different and are each a monovalent, divalent or trivalent unsubstituted or substituted hydrocarbon radical, X are identical or different and are each a chlorine atom or a radical of the formula --OR.sup.1, where R.sup.1 is a hydrogen atom or an alkyl radical which may be substituted by an ether oxygen atom, or a radical of the formula--R.sup.2 ([OCH(CH.sub.3)CH.sub.2 ].sub.e [OCH.sub.2 CH.sub.2 ].sub.f [O(CH.sub.2).sub.4 ].sub.g OR.sup.3).sub.y (II)where R.sup.2 is a divalent or trivalent, unsubstituted or substituted hydrocarbon radical which is substituted by one or more groups of the formulae--(C.dbd.O)--O--, --(C.dbd.O)--NR.sup.3 --, --NR.sup.3 --, --O--, --S--,R.sup.3 is a hydrogen atom or R.sup.1 or a radical of the formula--(C.dbd.O)--R.sup.1,e, f and g are each an integer of 0-200, with the proviso that the sum e+f+g.gtoreq.1 and y is 1 or 2,a is 0, 1 or 2,b is 0, 1, 2 or 3,c is 0, 1, 2 or 3 and the sum a+b+c.ltoreq.4, andA is a radical which contains an oligoisobutylene or polyisobutylene group, with the proviso that at least one radical of the formula A is present per molecule.