US4587284A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Absorbent polymer material and its preparation
Assignee: Ed Geistlich Soehne AG fuer Chemische Industrie
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Filing: 1985-06-14
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Granted: 1986-05-06
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Expires: 2005-06-14
Abstract
Abstract An enhanced water-absorbency hydrophilic polymer material, suitable for use in for example wound dressings, is prepared by a process in which a water-containing organic hydrogel comprising a gelable polysaccharide and/or protein or polypeptide interspersed with a polymer of a hydrophilic acrylic or methacrylic acid derivative is permeated with a base, the pH of said hydrogel being raised to at least 9 during treatment with said base.
Inventors
- 👤 Heinz Luissi
- 👤 Peter Geistlich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:59
CPC Classifications
C; C08; C08F; C08F251/00; A; A61; A61L; A61L15/00; A61L15/16; A61L15/22; A61L15/24; A61L15/28; A61L15/42; A61L15/60; C08F289/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
69 words
A process for preparing a hydrophilic polymer material in which a water-containing organic hydrogel comprising a gelable polysaccharide and/or protein or polypeptide interspersed with a polymer of a hydrophilic acrylic or methacrylic acid derivative is permeated with a base, the pH of said hydrogel being raised to at least 9 during treatment with said base, whereby the ability of said hydrogel to retain or absorb aqueous media is increased.
Claim 2
Dependent Claim
69 words
A process for preparing a hydrophilic polymer material in which a water-containing organic hydrogel comprising a gelable polysaccharide and/or protein or polypeptide interspersed with a polymer of a hydrophilic acrylic or methacrylic acid derivative is permeated with a base, the pH of said hydrogel being raised to at least 9 during treatment with said base, whereby the ability of said hydrogel to retain or absorb aqueous media is increased.
Claim 3
Dependent Claim
19 words
A process as claimed in claim 1 in which the hydrogel is agar-agar and the polymer is cross-linked acrylamide.
Claim 4
Dependent Claim
23 words
A process as claimed in claim 1 in which the hydrogel comprises 60 to 90% by weight of the acrylic or methacrylic polymer.
Claim 5
Dependent Claim
30 words
A process as claimed in claim 1 in which the base is an alkali metal hydroxide or quaternary ammonium hydroxide, ammonia or an amine with a molecular weight below 100.
Claim 6
Dependent Claim
44 words
A process as claimed in claim 1 in which the hydrogel is permeated with an aqueous solution containing at least 0.2% by weight of an alkali metal hydroxide, at least 0.5% by weight of ammonia or at least 1.0% by weight of an amine.
Claim 7
Dependent Claim
23 words
A process as claimed in claim 1 in which, after base treatment, the hydrogel is dried at a temperature not exceeding 80° C.
Claim 8
Dependent Claim
17 words
A process as claimed in claim 6 in which the base is removed before or during drying.
Claim 9
Dependent Claim
19 words
A process as claimed in claim 6 in which the dried hydrogel is comminuted to powder or granule form.
Claim 10
Dependent Claim
34 words
A process as claimed in claim 6 in which the dried hydrogel is contacted with water or an aqueous solution to yield a hydrogel which is incompletely hydrated and capable of absorbing further water.
Claim 11
Dependent Claim
32 words
A process as claimed in claim 9 in which the dried hydrogel is contacted with an aqueous solution containing one or more electrolytes, nutrients, physiologically active polypeptides or proteins and/or antibacterial agents.
Claim 12
Dependent Claim
46 words
A process as claimed in claim 9 in which the dried hydrogel is admixed with one or more electrolytes, nutrients, physiologically active polypeptides or proteins and/or antibacterial agents and the resultant admixture is contacted with water or an aqueous solution to yield said incompletely hydrated hydrogel.
Claim 13
Dependent Claim
44 words
A process as claimed in claim 9 in which in producing said incompletely hydrated hydrogel there is incorporated into the hydrogel zinc aspartate in an amount sufficient to yield a zinc content in said incompletely hydrated hydrogel of from 0.01% to 0.5% by weight.
Claim 14
Dependent Claim
14 words
A hydrophilic polymer material when produced by a process as claimed in claim 1.
Claim 15
Dependent Claim
20 words
A hydrophilic polymer material as claimed in claim 13 in paste form containing from 92 to 96% by weight water.
References Cited (Backward Citations)
US3618213A
Cited
US3965091A
Cited
US4200557A
Cited
US3980084A
Cited
US3871376A
Cited
US3997484A
Cited
US3901236A
Cited
US4076663A
Cited
US4028290A
Cited
US4192727A
Cited
GB1594389A
Cited
GB2036042A
Cited
US4541871A
Cited
US4487864A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |