Wound dressing materials

• US 4,233,969 A
• Filed: 11/10/1977
• Issued: 11/18/1980
• Est. Priority Date: 11/11/1976
• Status: Expired due to Term

• Current Assignee: David R. Webb, Peter M. Lock
• Original Assignee: David R. Webb, Peter M. Lock
• Inventors: Webb, David R., Lock, Peter M.
• Primary Examiner(s): Rosenbaum, C. Fred
• Application Number:
  US05/850,375
• Time in Patent Office: 1,104 Days
• Field of Search: 128/156, 128/296, 521/51
• US Class Current: 602/46
• CPC Class Codes: A61B 2017/00902 transparent or translucent
• CPC Class Codes: A61F 13/01017 synthetic, e.g. polymer based
• CPC Class Codes: A61F 13/069 Decubitus ulcer bandages
• CPC Class Codes: A61F 2013/00157 for burns or skin transplants A61F2013/00187 takes precedence; not adhering to the wound A61F2013/00217
• CPC Class Codes: A61F 2013/00217 not adhering to the wound
• CPC Class Codes: A61F 2013/00246 in a special way pervious to air or vapours
• CPC Class Codes: A61F 2013/00519 for treating burn
• CPC Class Codes: A61F 2013/00855 pervious to air or vapours
• CPC Class Codes: A61L 15/20 containing organic materials
• CPC Class Codes: A61L 15/26 Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof A61L15/225 takes precedence
• CPC Class Codes: C08G 18/4833 Polyethers containing oxyethylene units
• CPC Class Codes: C08L 75/04 Polyurethanes

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.

Claims

1. 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.

2. A dressing material according to claim 1, wherein the synthetic plastics material is a polyurethane which is prepared in the substantial absence of water.

3. 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.

4. 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.

5. 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.

6. 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.

7. A dressing material according to claim 5, wherein the cross-linking agent or catalyst is dimethylethanolamine.

8. 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).

9. A dressing material according to claim 4, wherein the alkylene surfactant contains ethylene oxide and propylene oxide.

10. 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.