Patent ID: 8748647

Claim:
A silicic acid polycondensate or partial polycondensate with the following structure (Ib) wherein the radicals and indices have the following meanings: R is an open-chain and/or cyclic alkylene, arylene, or alkylene-arylene group, with 1 to 10 carbon atoms in each case, which can be interrupted, by one or more oxygen or sulfur atoms or carboxyl or amino groups or can carry such atoms/groups at their end opposite the silicon atom, R 1 is a Z′-substituted, open-chain and/or cyclic alkylene, arylene, or alkylene-arylene group, with 1 to 10 carbon atoms in each case, which can be interrupted by one or more oxygen or sulfur atoms or carboxyl or amino groups or can carry such atoms/groups at their end opposite the silicon atom, R′ is an open-chain and/or cyclic alkyl, alkenyl, aryl, or alkylaryl, or arylalkyl group, with preferably 1 to 20 carbon atoms, the radicals R 3 are the same or different, both radicals have at least in part the meaning of a bond to another silicon atom and otherwise represent a hydrogen atom, an alkyl group with 1 to 10 carbon atoms, or a bond to another metal atom which can be inserted into silicic acid heteropolycondensates, B and B′ can be the same or different, both radicals can have the meaning of a straight-chain or branched organically polymerizable group with at least one C═C double bond and at least 2 carbon atoms, instead of this B′ can also mean —R 2 a SiX 4−a or —R 2 a R 1 b SiX 4−a−b , where R 2 is an alkylene group with 1 to 10 carbon atoms and R′ is defined as above, wherein X is a group which can enter into a hydrolytic condensation reaction with the formation of Si—O—Si bridges, Z′ has the meaning —NH—C(O)O—, —NH—C(O)—, or —CO(O)—, where the first two radicals named are bonded via the NH group to the group B′ while the carboxylate group can point in both directions, where, when Z′ is a —CO(O)— group, its carbon atom is bonded to the radical B′, the grouping B′—Z′— may not have the meaning of an acrylate group if B comprises an acrylate group, and the grouping B′—Z′— may not be a methacrylate group if B comprises a methacrylate group, a means 1 or 2, and b can be 0 or 1.