US4233969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wound dressing materials
Assignee: ANSONIA NOMINEES Ltd 1 LOVE LANE LONDON EC2
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Filing: 1977-11-10
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Granted: 1980-11-18
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Expires: 1997-11-10
Abstract
Abstract A wound dressing material, particularly for burns, comprises a sheet of synthetic plastics material which is permeable to water vapor and air, preferably a polyurethane produced by polymerization of an isocyanate capped polyoxyethylene polyol, without any substantial amount of water present, using a cross-linking agent which reacts with the isocyanate groups. The polyol and cross-linking agent, and preferably also an alkylene oxide surfactant, are agitated to form an aerated mix, spread on a release paper, and heated so that polymerization begins in the exposed upper surface, so as to form a sheet having a dense outer region which is impervious to liquids, a cellular region beneath the dense region, and a smooth glazed surface for application to a wound.
Inventors
- 👤 Peter M. Lock
- 👤 David R. Webb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:41
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/48; C08G18/4833; A; A61; A61F; A61F13/00; A61F13/01; A61F13/01008; A61F13/01017; A61L; A61L15/00; A61L15/16; A61L15/20; A61L15/22; A61L15/26; A61B; A61B17/00; A61B2017/00831; A61B2017/00902; A61F13/06; A61F13/064; A61F13/069; A61F2013/00089; A61F2013/00157; A61F2013/00217; A61F2013/00246; A61F2013/00361; A61F2013/00365; A61F2013/00519; A61F2013/00855
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
93 words
A wound dressing material, comprising a non-laminated sheet of a synthetic plastics material which is permeable to water vapour and to air and which is impermeable to liquid exudate, said material having on one side a smooth glazed surface for application to a wound, a closed cell cellular region behind the smooth surface, and a more dense region behind the closed cell cellular region, so that on contact with liquid exudate from a wound the dressing material will absorb a limited amount of exudate but prevent it from passing through the dressing material.
Claim 2
Dependent Claim
93 words
A wound dressing material, comprising a non-laminated sheet of a synthetic plastics material which is permeable to water vapour and to air and which is impermeable to liquid exudate, said material having on one side a smooth glazed surface for application to a wound, a closed cell cellular region behind the smooth surface, and a more dense region behind the closed cell cellular region, so that on contact with liquid exudate from a wound the dressing material will absorb a limited amount of exudate but prevent it from passing through the dressing material.
Claim 3
Dependent Claim
24 words
A dressing material according to claim 1, wherein the synthetic plastics material is a polyurethane which is prepared in the substantial absence of water.
Claim 4
Dependent Claim
36 words
A dressing material according to claim 2, wherein the synthetic plastics material is the product of polymerization of an isocyanate capped polyoxyethylene polyol employing a cross-linking agent or catalyst which is reactive with the isocyanate groups.
Claim 5
Dependent Claim
27 words
A dressing material according to claim 3, wherein the synthetic plastics material also incorporates an alkylene oxide surfactant to increase the hydrophilic nature of the dressing material.
Claim 6
Dependent Claim
31 words
A dressing material according to claim 3, wherein the cross-linking agent or catalyst contains in its molecule two or more amine and/or hydroxyl groups which are reactive with the isocyanate groups.
Claim 7
Dependent Claim
43 words
A dressing material according to claim 3, wherein the polyol is a polyoxyethylene diol having a weight average molecular weight of approximately 1500, containing a proportion of polyols having three or more hydroxyl groups, the diol and polyols having been capped with di-isocyanates.
Claim 8
Dependent Claim
15 words
A dressing material according to claim 5, wherein the cross-linking agent or catalyst is dimethylethanolamine.
Claim 9
Dependent Claim
45 words
A dressing material according to claim 6, wherein the cross-linking agent or catalyst is selected from the group comprising diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, glycerol, trimethylolpropane, pentaerythritol, tolylene-2,4,6-triamine, ethylene diamine, amino-ethanol, trimethylenediamine, tetramethylenediamine, pentamethylene-diamine, hexamethylene-diamine, ethanolamine, diethanolamine, hydrazine, triethanolamine, benzene-1,2,4-tricarboxylic acid, nitrilotriacetic acid, citric acid, 4,4'-methylenebis(o-chloroaniline).
Claim 10
Dependent Claim
17 words
A dressing material according to claim 4, wherein the alkylene surfactant contains ethylene oxide and propylene oxide.
Claim 11
Dependent Claim
26 words
A dressing material according to claim 9, wherein the proportions of ethylene oxide to propylene oxide lie in the range from 75:25% to 40:60% by weight.
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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) | 1983-11-18 | 1984-05-19 | 1984-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-18 | 1988-05-19 | 1988-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-18 | 1992-05-19 | 1992-11-18 | $7700.00 | Window Closed / Lapsed |