Patent ID: 7449219

Claim:
A method of making surface cross-linked superabsorbent polymer particles which comprises the steps of: a) providing a superabsorbent polymer comprising carboxyl groups for chemically reacting with a surface cross-linker, wherein the superabsorbent polymer is a particle selected from the group consisting of granules, flakes, spheres, powders, platelets, and beads; b) adding radiation activatable surface cross-linkers; and c) exposing said superabsorbent polymer and said radiation activatable surface cross-linkers to electromagnetic radiation, 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.