Mixture of polymeric alkyl silicates

An organosilicon compound comprising a mixture of polymeric alkyl silicates, comprising at least 90% by weight of a mixture of polymeric alkyl silicates of the formula (I)

• wherein
• the indices a, b, b′, c, c′, c″, d, d′, d″, d′″, e′, e″ and e′″ independently of one another indicate a number in the range from 0 to 5000, where the index e is a number in the range of 2 to 5000, with the proviso that the sum of all indices is at least 5;
• the radicals Rx are each independently selected from radicals that satisfy at least one of the following conditions:
• (a) Rx is a radical of the formula —CHRp2 or —CRp3,
• wherein Rp is each independently a monovalent unsubstituted or substituted hydrocarbon radical having 1 to 50 carbon atoms,
• (b) Rx is a substituted or unsubstituted, C5-C20 hydrocarbon radical that is doubly branched at the β-carbon atom,
• (c) Rx is an unsubstituted or alkyl-substituted cyclopentyl, cyclohexyl or cycloheptyl radical having a total of not more than 9 carbon atoms;
• the radicals Ry are each independently a hydrogen atom, a methyl, ethyl, n-propyl or n-butyl radical;
• in which the radicals ORy may be partially replaced by Si-bonded H atoms;
• Ry* is a methyl, ethyl, n-propyl or n-butyl radical;
• the radicals Rz are each independently a divalent unsubstituted or substituted radical bonded via carbon or a divalent radical bonded via silicon, in which individual carbon or Si atoms may be replaced by oxygen atoms;
• with the proviso that the units [O1/2RzO1/2] are bonded to two units independently selected from the group of units comprising [SiO4/2], [(RxO)SiO3/2], [(RyO)SiO3/2], [(RxO) 2SiO2/2], [(RxO) (RyO)SiO2/2], [(RyO) 2SiO2/2], [(RxO)3SiO1/2], [(RxO) 2 (RyO)SiO1/2], [(RxO) (RyO) 2SiO1/2] and [(RyO) 3 SiO1/2];
• with the proviso that the units [O1/2RZOH], [O1/2RZORX] and [O12RzORy*] are bonded to one unit independently selected from the group of units comprising [SiO4/2], [(RxO)SiO3/2], [(RyO)SiO3/2], [(RxO)2SiO2/2], [(RxO)(RyO)SiO2/2], [(RyO)2SiO2/2];
• with the proviso that the molar proportion of all radicals Ry in the polymeric alkyl silicate is at most 50 mol %, based on the molar amount of the sum of all radicals Rx, Ry and Ry*, wherein the molar fraction for the radical ORy equal to hydrogen is at most 33 mol %, based on the molar amount of the sum of all radicals ORx and ORy;
• and with the proviso that the following polymeric alkyl silicates, consisting exclusively of compounds of formula II, are excluded:
• wherein
• Z is a radical of formula —Si(ORb)3 or a radical of formula —CRc3,
• Ra is each independently a divalent unsubstituted or substituted carbon-bonded radical or a divalent silicon-bonded radical,
• Rb is each independently a monovalent unsubstituted or substituted hydrocarbon radical having 4 to 40 carbon atoms which is branched at the α-carbon atom or is doubly branched at the β-carbon atom,
• Rc is each independently a monovalent unsubstituted or substituted hydrocarbon radical having 1 to 50 carbon atoms,
• X is a halogen atom, an oxygen-bonded unsubstituted or substituted C1- to C40-hydrocarbon radical, wherein individual carbon atoms may be replaced by oxygen atoms, a radical of formula —O—Si(ORb)3 or a radical of formula —OSiRn3,
• Rn is each independently a monovalent unsubstituted or substituted C1- to C40-hydrocarbon radical and
• m is an integer of at least 2 and at most 1000.