Delayed-swelling absorbent systems
AssigneeKimberly-Clark Corporation
InventorsGerard M. Aberson, Gerard J. F. Ring
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Abstract
The invention comprises of an anionic polyelectrolyte hydrogel reversibly cross-linked with a polyvalent metal cation having a valence of at least two. This hydrogel may be combined with a removal agent for imparting delayed swelling characteristics when contacted with a water-containing fluid. The delayed swelling allows the water-containing fluid to penetrate or permeate the system before swelling is initiated, thereby providing enhanced wetting prior to the onset of swelling and alleviating gel blockage.
Claims19
An article of manufacture comprising an open support structure containing a water-swellable, water-absorbent system comprising an anionic polyelectrolyte reversibly cross-linked with polyvalent metal cations having a valence of at least two and a cation removal agent which upon contact with water-containing fluid is soluble therein and capable of reacting or complexing with the polyvalent metal cations cross-linking the anionic polyelectrolyte to thereby provide said system with delayed swelling characteristics when contacted with water-containing fluid, said system having delayed swelling characteristics when contacted with a water-containing fluid.
A water-swellable, water-absorbent system comprising an anionic polyelectrolyte reversibly cross-linked with polyvalent metal cations having a valence of at least two and a cation removal agent which upon contact with water-containing fluid is soluble therein and capable of reacting or complexing with the polyvalent metal cations cross-linking the anionic polyelectrolyte to thereby provide said system with delayed swelling characteristics when contacted with water-containing fluid, said system having delayed swelling characteristics when contacted with a water-containing fluid.
A water-absorbing system comprising substantially nonabsorbent anionic polyelectrolyte reversibly cross-linked with polyvalent metal cations having a valence of at least two (2) and a cation removal agent which upon contact with water-containing fluid is soluble therein and capable of reacting or complexing with the polyvalent metal cations cross-linking the anionic polyelectrolyte to thereby provide said system with delayed swelling characteristics when contacted with water-containing fluid.
A method for preparing an anionic polyelectrolyte reversibly cross-linked with a polyvalent metal cation to an extent that the superabsorbency characteristics of said polyelectrolyte have been substantially reduced comprising providing an imcompletely cross-linked anionic polyelectrolyte, contacting said polyelectrolyte with an aqueous solution of a salt of a polyvalent metal cation to complete cross-linking and form substantially nonabsorbent material, removing water to recover cross-linked polyelectrolyte and combining said cross-linked recovered polyelectrolyte with a cation removal agent under conditions such that said removal agent does not react or complex with the polyvalent metal cations cross-linking said polyelectrolyte.
Dependencies are inferred from the claim text.