US4548847A
Expired / Lapsed
US
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Delayed-swelling absorbent systems
Assignee: Kimberly Clark Worldwide Inc
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Filing: 1984-01-09
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Granted: 1985-10-22
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Expires: 2004-01-09
Abstract
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.
Inventors
- 👤 Gerard M. Aberson
- 👤 Gerard J. F. Ring
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:20
CPC Classifications
A; A61; A61F; A61F13/00; A61F13/15; A61F13/53; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; A61F13/20; A61F13/2002; A61F13/202; A61F13/534; A61F13/53409; A61F2013/15008; A61F2013/15048; A61F2013/15073; A61F2013/530481; A61F2013/530708; A61F2013/530715; A61F2013/530722; A61F2013/53445; A61F13/84; A61F2013/8488; Y; Y10; Y10S; Y10S34/00; Y10S34/01; Y10S428/00; Y10S428/913; Y10S524/00; Y10S524/916; Y10T; Y10T428/00; Y10T428/23; Y10T428/237; Y10T428/24; Y10T428/24802; Y10T428/24851; Y10T442/00; Y10T442/20; Y10T442/2484; Y10T442/60; Y10T442/659
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
86 words
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.
Claim 2
Dependent Claim
86 words
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.
Claim 3
Dependent Claim
13 words
The article of claim 1 wherein said cation removal agent comprises a ligand.
Claim 4
Dependent Claim
32 words
The article of claim 1 wherein said cation removal agent is selected from the group consisting essentially of sodium phosphate dibasic, the disodium salt of ethylenediamine-tetraacetic acid, sodium hexametophosphate and mixtures thereof.
Claim 5
Dependent Claim
21 words
The article of claim 1 wherein said anionic polyelectrolyte is partially cross-linked by another means in addition to said metal cation.
Claim 6
Dependent Claim
14 words
The article of claim 1 wherein said open support structure is a fibrous mat.
Claim 7
Dependent Claim
76 words
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.
Claim 8
Dependent Claim
76 words
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.
Claim 9
Dependent Claim
13 words
The system of claim 6 wherein said cation removal agent comprises a ligand.
Claim 10
Dependent Claim
32 words
The system of claim 6 wherein said cation removal agent is selected from the group consisting essentially of sodium phosphate dibasic, the disodium salt of ethylenediaminetetraacetic acid, sodium hexametophosphate and mixtures thereof.
Claim 11
Dependent Claim
21 words
The system of claim 6 wherein said anionic polyelectrolyte is partially cross-linked by another means in addition of said metal cation.
Claim 12
Dependent Claim
19 words
A method for the absorption of a water-containing fluid comprising contacting said fluid with the system of claim 1.
Claim 13
Dependent Claim
65 words
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.
Claim 14
Dependent Claim
65 words
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.
Claim 15
Dependent Claim
24 words
The system of claim 11 wherein said anionic polyelectrolyte is partially cross-linked by another means in addition to the cross-linking of said metal cation.
Claim 16
Dependent Claim
13 words
The system claim 11 wherein said cation comprises magnesium, barium, or combinations thereof.
Claim 17
Dependent Claim
10 words
The system of claim 11 wherein said cation comprises calcium.
Claim 18
Dependent Claim
32 words
The combination of claim 11 wherein said cation removal agent is selected from the group consisting essentially of sodium phosphate dibasic, the disodium salt of ethylenediamine-tetraacetic acid, sodium hexametophosphate and mixtures thereof.
Claim 19
Independent Claim
95 words
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.
Claim 20
Independent Claim
95 words
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.
Claim 21
Dependent Claim
23 words
The method of claim 16 wherein said anionic polyelectrolyte is partially cross-linked by another means prior to reversible cross-linking with said metal cation.
Claim 22
Dependent Claim
14 words
The method of claim 16 wherein said cation comprises magnesium, barium, or combinations thereof.
Claim 23
Dependent Claim
10 words
The method of claim 16 wherein said cation comprises calcium.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |