Absorbent materials and absorbent articles incorporating such absorbent materials
View Patent ↗An absorbent material formed at least in part of a crosslinked polymer. The absorbent material has a centrifuge retention capacity as determined by a Centrifuge Retention Capacity Test of at least about 20 g/g and a gel bed permeability under load as determined by a Gel Bed Permeability Under Load Test of at least about 300×10 −9 cm 2 or a free swell gel bed permeability as determined by a Free Swell Gel Bed Permeability Test of at least about 2,500×10 −9 cm 2 . The crosslinked polymer may comprise either at least about 75 weight percent anionic polymer or at least about 75 weight percent cationic polymer. In one embodiment, the cross-linked polymer is surface treated with a water soluble non-cross-linked polymer having a potential for becoming charged opposite that of the cross-linked polymer.
1. An absorbent material consisting essentially of a superabsorbent polymer consisting of
a) at least about 75% by weight of the superabsorbent polymer of an anionic polymer comprising functional groups selected from carboxyl groups, sulfonate groups, sulphate groups, sulfite groups, and phosphate groups; and
b) an internal crosslinking agent based on the polymerizable unsaturated acid group containing monomer, wherein the superabsorbent polymer has a degree of neutralization of greater than about 25%; wherein elements a) and b) are polymerized and prepared into superabsorbent polymer particles and further comprising the following surface additives to form surface treated superabsorbent polymer particles
i) from about 0.5% to about 5% by weight of surface crosslinking agent based on the superabsorbent polymer composition; and
ii) from about 0.63% to about 5% by weight of a non-cross linked cationic polymeric coating based on the superabsorbent polymer composition;
said absorbent material having a centrifuge retention capacity as determined by a Centrifuge Retention Capacity Test of at least about 20 g/g and a gel bed permeability under load as determined by a Gel Bed Permeability Under Load Test of at least about 300×10 −9 cm 2 .
2. The absorbent material of claim 1 wherein the absorbent material has a gel bed permeability under load as determined by the Gel Bed Permeability Under Load Test of at least about 400×10 −9 cm 2 .
3. The absorbent material of claim 1 wherein the absorbent material has a centrifuge retention capacity as determined by a Centrifuge Retention Capacity Test of at least about 25 g/g.
4. The absorbent material of claim 1 wherein the absorbent material has a free swell gel bed permeability as determined by a Free Swell Gel Bed Permeability Test of at least about 2,000×10 −9 cm 2 .
5. The absorbent material of claim 4 wherein the absorbent material has a free swell gel bed permeability as determined by the Free Swell Gel Bed Permeability Test of at least about 3,000×10 −9 cm 2 .
6. The absorbent material of claim 4 wherein the absorbent material has a free swell gel bed permeability as determined by the Free Swell Gel Bed Permeability Test of at least about 2,500×10 −9 cm 2 .
7. The absorbent material of claim 1 wherein the superabsorbent polymer comprises at least about 85% by weight of an anionic polymer.