Organically modified siloxanes and their use for producing preparations for water-repellent impregnations for mineral building materials

An organomodified siloxane compound of the general formula (I)

• where
• the radicals R1 are identical or different radicals selected from the group consisting of linear or branched, saturated or monounsaturated or polyunsaturated alkyl, aryl, alkylaryl or arylalkyl radicals having from 1 to 20 carbon atoms,
• the radicals R2 are identical or different alkylene radicals which have from 1 to 20 carbon atoms,
• R3 is an oxyalkylene radical of the formula (II),
• where
• R3a, R6a, R6b are each, independently of one another, hydrogen, preferably methyl and/or ethyl or can each be a branched or unbranched, unsubstituted or heteroatom-substituent-bearing, saturated or unsaturated alkyl or aryl radical and
• k is from 2 to 11,
• a, b are each, independently of one another, a number in the range from 1 to 4 and
• na, nb are each, independently of one another, a number in the range from 0 to 50, where 1<na+nb≦50,
• with the proviso that a random or blockwise arrangement of the oxyalkylene units can be present,
• the radicals R4 are each, independently of one another, R1, —R2—Si(R5)3, R3 or H,
• the radicals R5 are identical or different alkyl, alkoxy, aryl, aryloxy or alkenyl radicals having from 1 to 20 carbon atoms, preferably a methoxy and/or ethoxy group, with the proviso that at least one R5 is an alkoxy group,
• n is from 1 to 20,
• m is from 0 to 20, with m only being 0 when R4 is the radical —R2—Si(R5)3 and otherwise being ≧1,
• o is from 0 to 20,
• p is from 1 to 200.