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The invention relates to absorptive, crosslinked polymeric composition that are based on partly neutralized, monoethylenically unsaturated monomer carrying acid groups wherein the absorptive crosslinked polymer may be coated with a polymeric coating, and have improved properties, in particular in re

The invention relates to absorptive, crosslinked polymeric composition that are based on partly neutralized, monoethylenically unsaturated monomer carrying acid groups wherein the absorptive crosslinked polymer may be coated with a polymeric coating, and have improved properties, in particular in respect of their capacity for transportation of liquids in the swollen state, and which have a high capacity and a high gel bed permeability.

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1. A method to make a high-capacity superabsorbent polymer composition comprising the steps of: a) preparing a superabsorbent polymer by the process of polymerizing from about 55% to about 99.9% by weight of polymerizable unsaturated acid group containing monomer based on the superabsorbent polymer,

1. A method to make a high-capacity superabsorbent polymer composition comprising the steps of: a) preparing a superabsorbent polymer by the process of polymerizing from about 55% to about 99.9% by weight of polymerizable unsaturated acid group containing monomer based on the superabsorbent polymer, and from about 0.001% to about 5% by weight of an internal crosslinking agent based on the polymerizable unsaturated acid group containing monomer, and wherein the superabsorbent polymer has a degree of neutralization of greater than about 25%;b) preparing superabsorbent polymer particles from the superabsorbent polymer;c) treating the superabsorbent polymer particles with surface additives including: i) from about 0.001% to about 5% by weight of surface crosslinking agent based on the superabsorbent polymer composition;ii) from about 0.01% to about 2% by weight of a water-insoluble, inorganic metal compound based on the superabsorbent polymer composition wherein said water-insoluble inorganic metal compound is selected from a calcium phosphate, titanium phosphate, aluminum phosphate, iron phosphate, titanium borate, aluminum borate, iron borate magnesium borate, manganese borate, or calcium borate;iii) from about 0.01% to about 0.5% cationic polymer based on the superabsorbent polymer composition is applied on the particle surface;iv) from about 0.01% to about 0.5% of a thermoplastic polymer that is selected from polyolefin, polyethylene, linear low density polyethylene, ethylene acrylic acid copolymer, styrene copolymers, ethylene alkyl methacrylate copolymer, polypropylene, maleated polypropylene, ethylene vinyl acetate copolymer, polyamide, polyester, blends thereof, or copolymers thereof;d) heat-treating the coated superabsorbent polymer particle wherein the heat-treating may be done after application of the surface crosslinking agent. 2. The method of claim 1 wherein in step a) at least about 50 weight % the acid groups include carboxyl groups, the acid groups are neutralized to at least 50 mol %, and the internal crosslinking agent is from about 0.2 weight % to about 3 weight % based on the total amount of the polymerizable unsaturated acid group containing monomer. 3. The method of claim 1 wherein the heat treatment of the coated superabsorbent polymer is from about 150° C. to about 250° C. 4. The method of claim 1 wherein the particles of inorganic metal compound have a mass median particle size of less than about 2 μm. 5. The method of claim 1 wherein the high-capacity superabsorbent polymer composition has a Centrifuge Retention Capacity of at least about 30 g/g and a free swell gel bed permeability as measured by the Free Swell Gel Bed Permeability Test of at least about 10 Darcy. 6. The method of claim 1 wherein the thermoplastic polymer is a maleated polypropylene. 7. The method of claim 1 wherein the thermoplastic polymer is a blend of maleated polypropylene and ethylene acrylic acid copolymer. 8. The method of claim 1 wherein the cationic polymer is a polyvinylamine. 9. The method of claim 1 wherein a water insoluble, inorganic metal compound is in suspension form. 10. The method of claim 1 wherein a water insoluble, inorganic metal compound is applied in dry form. 11. The method of claim 1 wherein the high-capacity superabsorbent polymer composition has at least about 40% by weight of the dry superabsorbent polymer having a particle size from about 300 μm to about 600 μm. 12. The method of claim 1 wherein the surface crosslinking agent omprises ethylene carbonate. 13. The method of claim 1 wherein the surface additives furher comprise from about 0.01 wt % of the dry superabsorbent polymer compoisiton of silica. 14. The method of claim 1 wherein the surface additives further comprise an odor-binding substance. 15. The method of claim 1 wherein the surface additives further comprise an anti-caking additive. 16. The method of claim 1 wherein the surface additives further comprise a flow modification agent. 17. The method of claim 1 wherein the surface additives further comprise a viscosity modifier.