Patent ID: 7166356

Claim:
Superabsorbent polymer particles comprising a water-absorbing resin that has been reacted with a radiation activatable surface cross-linker wherein the reaction product of the radiation activatable surface cross-linker and the water absorbing resin is present at surfaces of the superabsorbent polymer particles, wherein said radiation activatable surface cross-linker comprises at least two radiation activatable groups R, said at least two radiation activatable groups R being covalently bound to each other or to at least one spacer group S, wherein the spacer group S is a spacer group selected from the group consisting of an organic group with a molecular weight of up to about Mw=10000, and a polymeric group with a molecular weight of up to about Mw=1000000, and wherein said radiation activatable groups R are the same or different and are selected from the group consisting of: a) acetophenone, benzophenone, anthraquinone, xanthone, thioxanthone, camphorquinone, terephthalophenone benzil, fluorenone, -ketocoumarin and acetophenone-, benzophenone-, anthraquinone-, xanthone-, thioxanthone-, camphorquinone-, terephthalophenone-, benzil-, fluorenone-, and -ketocoumarin-derivatives, wherein acetophenone derivatives and benzophenone derivatives also comprise condensation products of acetophenone derivatives or benzophenone derivatives, comprising at least two acetophenone or benzophenone groups, and b) a group comprising a first group selected from the group consisting of methyl, benzyl, aryl, phenyl and substituted phenyl, and a second group selected from the group consisting of an aryl, an alkyl of 1 to 4 carbon atoms, cyclopropyl, cyclopentyl, cyclohexyl, α,α-dialkoxyalkyl, and α-hydroxyalkyl and wherein said first group is covalently bound to said second group via an additional carbonyl group therebetween, and wherein the second group is covalently bound to said spacer group S or to another radiation activatable group.