METHOD FOR THE SECONDARY CROSSLINKING OF HYDROGELS WITH BICYCLIC AMIDE ACETALS

摘要

The invention relates to a method for the secondary crosslinking of water-absorbing polymers by treating said polymer with a secondary crosslinking agent and subsequently crosslinking and drying the same during or after said treatment by increasing the temperature. The inventive secondary crosslinking agent is a compound of formula I wherein R<1>, R<2>, R<3>, R<4>, R<5>, R<6>, R<7>, R<8>, and R<9> independently represent hydrogen, C1-C12 alkyl, C2-C12 alkenyl, or C6-C12 aryl, C1-C12 alkyl, C2-C12 alkenyl, or C6-C12 aryl being optionally substituted by halogen. Also disclosed are said liquid-absorbing polymers and the use thereof in hygiene products and packaging materials.