Patent ID: 8466228

Claim:
A particulate superabsorbent polymer composition comprising: a) from about 55 to about 99.9 wt. % of a monomer, which contain carboxyl groups including acrylic acid, methacrylic acid, or mixtures of these monomers wherein the monomer is neutralized to from 50 to 80 mol %; b) from about 0.001 to about 3.0 wt. % based on the weight of a) of internal crosslinking agent; wherein elements a) and b) are polymerized into a polymer gel which is then dried in a forced air oven to have a moisture content of less than 5 wt %, and comminuted into particulate superabsorbent polymer composition having a particle size of from 150 to 850 μm and a particle surface and further comprising c) from about 0.001 to about 5.0 wt. % based on a dry polymer powder weight of an alkylene carbonate applied to the particle surface in a surface crosslinking step; d) from about 0.01% to about 5 wt. % based on the dry polymer powder weight of polyethylene glycol or tetraethyleneglycol dimethylether added immediately prior to or during the surface crosslinking step; e) from about 0.01 wt. % to about 5 wt. % based on the dry polymer powder weight of a multivalent metal salt selected from aluminum sulfate on the particle surface; f) from about 0.01 to about 5 wt % based on the dry polymer powder weight of a water-insoluble, inorganic powder selected from kaolin, silicon dioxide, fumed silica, silicic acid, silicates, titanium dioxide, aluminum oxide, fumed alumina, calcium phosphate, or clays; and g) from about 0.1 to about 0.3 wt % based on the dry polymer powder weight of a surfactant selected from disodium cocoamphopropionate or cocomonoethanol amide with 4.5 moles ethoxylation; wherein the composition has a degree of neutralization of more than about 25%; and a Centrifuge Retention Capacity of from about 23 g/g to about 40 g/g as determined by the Centrifuge Retention Capacity Test set forth herein and a gel bed permeability of from about 400×10 −9 cm 2 to about 2500×10 −9 cm 2 as determined by the Gel Bed Permeability Test set forth herein.