Patent ID: 8445596

Claim:
A superabsorber particulate composition having a surface which has been subjected to secondary crosslinking at its surface, comprising a polymer comprising a) from about 55 to about 99.9 wt % of polymerized, ethylenically unsaturated monomers comprising acrylic acid and are neutralized to 50-80 mole %, b) from 0 to about 40 wt % of polymerized, ethylenically unsaturated monomers copolymerizable with a), c) from about 0.1 to about 5.0 wt % of one or more polymerized crosslinkers, d) from 0 to about 30 wt % of a water soluble polymer, wherein the sum of the weight amounts a) through d) is 100 wt % and wherein the polymer is formed into a particulate superabsorber polymer product having a particle size from about 20 μm to 2000 μm, wherein the particulate superabsorber polymer product has been crosslinked on the surface thereof with an aqueous combination consisting of e) from about 1 to about 2 wt %, relative to the polymer product, of an organic surface secondary crosslinking agent consisting of 1,3-dioxolan-2-one, with the exception of polyols, and f) from about 0.3 to about 1 wt %, relative to the polymer product, of a compound selected from aluminum sulfate 14-hydrate, aluminum sulfate 18-hydrate, aluminum chloride 6-hydrate, ferric chloride, calcium acetate hydrate, or magnesium acetate 4-hydrate, to form a treated particulate superabsorber polymer, and the treated particulate superabsorber polymer has been subjected to surface secondary crosslinking wherein the surface secondary crosslinking reaction excludes polyols and is performed at temperatures from about 160° C. to about 210° C. to form the superabsorber particulate composition, wherein the amount of water used for the treatment of the particulate superabsorber polymer product with the an aqueous combination consisting of the organic surface secondary crosslinking agent consisting of 1,3-dioxolan-2-one of e) and the compound selected from aluminum sulfate 14-hydrate, aluminum sulfate 18-hydrate, aluminum chloride 6-hydrate, ferric chloride, calcium acetate hydrate, or magnesium acetate 4-hydrate of f) is from about 0.5 to about 10 wt % relative to the particulate superabsorber polymer product, wherein the superabsorber particulate composition has a permeability as measured by the saline flow conductivity test, SFC, of from about 40×10 −7 cm 3 s/g to about 150×10 −7 cm 3 s/g; and a retention as measured by the tea bag test, TB, of from about 23.5 g/g to about 40 g/g and a AAP 0.7 of from about 22.5 to about 25.5 g/g as measured by the liquid absorption under pressure at 0.7 psi.