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Patent US4587284A successfully refreshed from Google Patents.
US4587284A
Expired / Lapsed
US
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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 20:06
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.
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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 |