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

US6297335A · kind A · utility

Assignee

• BASF SE

Inventors

• Rüdiger Funk · Niedernhausen, DE
• Norbert Herfert · Charlotte, US
• Mariola Wanior · Niederrodenbach, DE
• Patricia Brown · Charlotte, US
• Fritz Engelhardt · Frankfurt am Main, DE
• Guy Thomas Woodrum · Chesapeake, US

Key dates

• Filing date: Feb 5, 1999
• Grant date: Oct 2, 2001
• Expiry date: Feb 5, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F8/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

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 PA0 (a) a copolymerization crosslinker which contains at least two ethylenically unsaturated double bonds in the molecule, and PA0 (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.