Method for the secondary cross-linking of hydrogels with 2-oxotetrahydro-1,3-oxazines

Abstract

Liquid-absorbent polymers are prepared by a process for the gel and/or surface postcrosslinking of water-absorbent polymers by the polymer being treated with a surface postcrosslinking solution and being postcrosslinked and dried during and after the treatment by raising the temperature, wherein the crosslinker comprises a compound of the formula I where R1 is hydrogen, C1-C4-alkyl, C1-C4-hydroxyalkyl, trialkylsilyl or acetyl and R2, R2′, R3, R3′, R4, R4′ are each independently hydrogen, C1-C12-alkyl, C2-C12-alkenyl or C6-C12-aryl, dissolved in an inert solvent, and are used in hygiene articles, packaging materials and nonwovens.

Dependencies are inferred from the claim text.