Water-soluble or water-swellable crosslinked copolymers

1. A water-soluble or water-swellable crosslinked copolymer consisting essentially of

a1) 1 to 50% by weight of a repeating structural unit of formula (1)

 where n is an integer from 2 to 9, or

a2) 1 to 50% by weight of a mixture of the repeating structural unit of the formula (1) and a repeating structural unit of formula (2)

 where R, R 1 and R 2 may be identical or different and are hydrogen or a linear or branched alkyl or alkenyl group having in each case 1 to 30 carbon atoms and

b) 49.99 to 98.99% by weight of a repeating structural unit of formula (3)

 in which R 3 is hydrogen, methyl or ethyl, Z is C 1 –C 8 -alkylene, and X is an alkali metal or alkaline earth metal ion, and

c) 0.01 to 8% by weight of crosslinking structures resulting from a monomer having at least two olefinic double bonds.

2. The copolymer as claimed in claim 1 , consisting essentially of 2 to 30% by weight of component a1) or mixture a2), 69.5 to 97.5% by weight of component b) and 0.2 to 3% by weight of component c).

3. The copolymer as claimed in claim 1 , consisting essentially of 3 to 15% by weight of component a1) or mixture a2), 84.5 to 96.5% by weight of component b) and 0.5 to 2% by weight of component c).

4. The copolymer as claimed in claim 1 , wherein the monomer of component c) is allyl (meth)acrylate.

5. A cosmetic preparation or a pharmaceutical preparation comprising the water-soluble or water-swellable crosslinked copolymer of claim 1 .

6. The water-soluble or water-swellable crosslinked copolymer of claim 1 wherein R, R 1 and R 2 are a linear or branched alkyl or alkenyl group having in each case 1 to 20 carbon atoms.

7. The water-soluble or water-swellable crosslinked copolymer of claim 1 wherein R, R 1 and R 2 are a linear or branched alkyl or alkenyl group having in each case 1 to 12 carbon atoms.

8. A water-soluble or water-swellable crosslinked copolymer consisting essentially of

a) 1 to 50% by weight of a mixture of a structural unit of formula (1)

 where n is an integer from 2 to 9, and a structural unit of formula (2),

 where R, R 1 and R 2 may be identical or different and are hydrogen or a linear or branched alkyl or alkenyl group having in each case 1 to 30, carbon atoms, and

b) 49.99 to 98.99% by weight of a repeating structural unit of the formula (3)

 in which R 3 is hydrogen, methyl or ethyl, Z is C 1 –C 8 -alkylene, and X is an alkali metal or alkaline earth metal ion, and

c) 0.01 to 8% by weight of crosslinking structures resulting from monomers having at least two olefinic double bonds.

9. The water-soluble or water-sellable crosslinked copolymer of claim 1 , wherein in component c) the monomer is selected from the group consisting of allyl acrylate, allyl methacrylate, allyl ethyl methacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, dipropylene glycol diallyl ether, polyglycol diallyl ether, triethylene glycol divinyl ether, hydroquinone diallyl ether, tetraallyloxyethane, tetraethylene glycol diacrylate, triallylamine, trimethylolpropane diallyl ether, methylene bisacrylamide, divinylbenzene, and mixtures thereof.

10. The water-soluble or water-swellable crosslinked copolymer of claim 8 , wherein in component c) the monomers are selected from the group consisting of allyl acrylate, allyl methacrylate, allyl ethyl methacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, dipropylene glycol diallyl ether, polyglycol diallyl ether, triethylene glycol divinyl ether, hydroquinone diallyl ether, tetraallyloxyethane, tetraethylene glycol diacrylate, triallylamine, trimethylolpropane diallyl ether, methylene bisacrylamide, divinylbenzene, and mixtures thereof.

11. A cosmetic preparation or a pharmaceutical preparation comprising the water-soluble or water swellable crosslinked copolymer of claim 8 .