Crosslinked, hydrophilic, highly swellable hydrogels, production thereof and use thereof

Abstract

The hydrogels are based on polymerized monomers or on graft polymers and each have a Pressure Absorbency Index <100 and a vertical absorption of not less than 12 g/g under a pressure of 1922.8 Pa. They are produced by free-radically polymerizing hydrophilic monomers which contain acid groups, or their alkali metal or ammonium salts, with (a) a copolymerization crosslinker which contains at least two ethylenically unsaturated double bonds in the molecule, and (b) a reactive crosslinker A which contains an ethylenically unsaturated double bond and at least one functional group capable of forming covalent bonds with the acid groups of the hydrophilic polymers, a reactive crosslinker B which contains at least two functional groups capable of forming covalent bonds with the acid groups of the hydrophilic polymers, and/or with ions of polyvalent metals optionally in the presence of at least one grafting base to form a crosslinked, hydrophilic base polymer, comminuting said base polymer and postcrosslinking the surface of the particles of said base polymer, and are useful as absorbents for water and aqueous fluids.

Dependencies are inferred from the claim text.