US4076928A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Substantially dry water swellable particulate polyelectrolyte
Assignee: Dow Chemical Co
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Filing: 1975-08-20
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Granted: 1978-02-28
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Expires: 1995-08-20
Abstract
Abstract Water swellable absorbent articles, made from copolymers having a copolymerized crosslinker, together with methods for their preparation, and a composition containing a copolymerized crosslinker useful to make said articles are disclosed. The copolymers comprise 25-98% by weight of an alkali metal salt of an olefinically unsaturated monosulfonic or monocarboxylic acid, about 2-50% by weight of an olefinically unsaturated monocarboxylic acid and about 0.1-5.0% by weight of an N-substituted acrylamide or methacrylamide. The articles are crosslinked by heating and/or removing substantially all of the water from the precursor composition. The crosslinked compositions, in the form of a film, can be disintegrated to form flakes, strips or powders. The absorbent articles are useful as surgical sponges, diapers, tampons, meat trays, bath mats and the like.
Inventors
- 👤 James R. Gross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:07
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/04; A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; C08F212/00; C08F212/02; C08F212/04; C08F212/14; C08F212/16; C08F212/20; C08F212/30; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T442/00; Y10T442/20; Y10T442/2484
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
176 words
A substantially dry water swellable particulate polyelectrolyte produced by the method which comprises 1. preparing a solution, I. which comprises a solvent selected from the group consisting of water, lower alcohols and mixtures thereof, and Ii. about 5 to about 60% by weight based on (I) of a crosslinkable carboxylic copolymer which contains in the copolymer A. about 25 to about 98% by weight based on the total weight of the copolymer of units derived from an alkali metal salt of an olefinically unsaturated monosulfonic or monocarboxylic acid; B. about 2 to about 50% by weight of units derived from an olefinically unsaturated monocarboxylic acid; and C. about 0.1 to about 5.0% by weight of units derived from an N-substituted acrylamide or methacrylamide having the formula H.sub.2 C=CR--C(O)--NHCH.sub.2 --O--R' wherein R is selected from hydrogen or methyl and R' is hydrogen or an alkyl group of 1-8 carbons, 2. spreading a coating of said solution on an impervious substrate, 3. heating said coated substrate to a temperature greater than about 30° C to crosslink said polyelectrolyte,
Claim 2
Dependent Claim
176 words
A substantially dry water swellable particulate polyelectrolyte produced by the method which comprises 1. preparing a solution, I. which comprises a solvent selected from the group consisting of water, lower alcohols and mixtures thereof, and Ii. about 5 to about 60% by weight based on (I) of a crosslinkable carboxylic copolymer which contains in the copolymer A. about 25 to about 98% by weight based on the total weight of the copolymer of units derived from an alkali metal salt of an olefinically unsaturated monosulfonic or monocarboxylic acid; B. about 2 to about 50% by weight of units derived from an olefinically unsaturated monocarboxylic acid; and C. about 0.1 to about 5.0% by weight of units derived from an N-substituted acrylamide or methacrylamide having the formula H.sub.2 C=CR--C(O)--NHCH.sub.2 --O--R' wherein R is selected from hydrogen or methyl and R' is hydrogen or an alkyl group of 1-8 carbons, 2. spreading a coating of said solution on an impervious substrate, 3. heating said coated substrate to a temperature greater than about 30° C to crosslink said polyelectrolyte,
Claim 3
Dependent Claim
20 words
separating said crosslinked polyelectrolyte film from said substrate, and 5. disintegrating said film to form flakes, strips, or powders thereof.
Claim 4
Dependent Claim
20 words
separating said crosslinked polyelectrolyte film from said substrate, and 5. disintegrating said film to form flakes, strips, or powders thereof.
Claim 5
Dependent Claim
42 words
The particulate polyelectrolyte as set forth in claim 1 wherein the crosslinkable carboxylic copolymer contains 90 weight percent of units derived from sodium acrylate, 9 weight percent of units derived from acrylic acid and 1.0 weight percent of units derived from N-methylolacrylamide.
Claim 6
Dependent Claim
43 words
The particulate polyelectrolyte as set forth in claim 1 wherein the crosslinkable carboxylic copolymer contains 79 weight percent of units derived from sodium styrene sulfonate, 20 weight percent of units derived from acrylic acid and 1.0 weight percent of units derived from N-methylolacrylamide.
Claim 7
Dependent Claim
42 words
The particulate polyelectrolyte as set forth in claim 1 wherein the crosslinkable carboxylic copolymer contains 90 weight percent of units derived from sodium acrylate, 9 weight percent of units derived from acrylic acid and 1.0 weight percent of units derived from N-isobutoxymethylacrylamide.
Claim 8
Dependent Claim
42 words
The particulate polyelectrolyte as set forth in claim 1 wherein the crosslinkable carboxylic copolymer contains 79.7 weight percent of units derived from sodium acrylate, 20 weight percent of units derived from acrylic acid, and 0.3 weight percent of units derived from N-methylolacrylamide.
Claim 9
Dependent Claim
16 words
The particulate polyelectrolyte as set forth in claim 1 wherein the crosslinking agent is N-isobutoxymethyl acrylamide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-27 | 1981-08-29 | 1982-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-27 | 1985-08-29 | 1986-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-27 | 1989-08-29 | 1990-02-28 | $7700.00 | Window Closed / Lapsed |