Polyurethane foam dressing

• US 4,960,594 A
• Filed: 09/22/1988
• Issued: 10/02/1990
• Est. Priority Date: 09/22/1988
• Status: Expired due to Fees

• Current Assignee: Derma-Lock Medical Corp. (Quest Diagnostics Incorporated)
• Original Assignee: Derma-Lock Medical Corp. (Quest Diagnostics Incorporated)
• Inventors: Honeycutt, Travis W.
• Primary Examiner(s): Cashion, Jr., Merrell C.
• Assistant Examiner(s): HORNE, LEON
• Application Number:
  US07/247,871
• Time in Patent Office: 740 Days
• Field of Search: 424/445
• US Class Current: 424/445
• CPC Class Codes: A61F 13/01042 Absorbency
• CPC Class Codes: A61F 13/01046 Air-vapor permeability
• 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 2013/00263 vapour permeability >500 g/m2/24h
• CPC Class Codes: A61F 2013/00519 for treating burn bandages for burns or skin transplants A61F2013/00157
• CPC Class Codes: A61F 2013/0074 containing foams
• CPC Class Codes: A61F 2013/00876 vapour permeability >500 g/mg/24h
• 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: A61L 15/425 Porous materials, e.g. foams or sponges
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

A polyurethane foam wound dressing and a method for making the dressing is described. The dressing is made from the reaction of a polyurethane prepolymer with a difunctional cross-linking agent in the presence of DMEA and substantial amounts of water. The resulting dressing has a glazed, mirror-smooth surface for application to the wounded area and an insular region to maintain the wound at near body temperature. The dressing has a moisture vapor transmission rate that is close to the capacity of the wound surface to produce serous exudate.

Claims

1. A wound dressing material consisting essentially of a nonadherent, thin film, foam polyurethane membrane having a substantially smooth surface for application to a wounded area and an insulating region adjacent said smooth surface for maintaining the wound near body temperature, wherein said wound dressing is formed in the presence of a substantial amount of water to enhance CO₂ formation and exhibits a moisture vapor transmission rate greater than 0.30 grams/inch² / day.

2. The wound dressing of claim 1 wherein said membrane has a density less than 0.6 grams/centimeter³.

3. The wound dressing of claim 1 wherein said membrane exhibits an absorbance based on dry weight of greater than 20%.

4. The wound dressing of claim 1 wherein said membrane is formed by the reaction of a polyurethane prepolymer, a catalyst and a cross-linking agent.

5. The wound dressing of claim 4 wherein said polyurethane prepolymer is selected from the group consisting of a polyethyelene glycol diol with available isocyanate groups, a polyoxyethylene diol with available isocyanate groups, a mixture of a polyester and a diisocyanate, and a mixture of a polyether, a diisocyanate, and a polyoxypropylene diol capped with at least two diisocyanate end groups.

6. The wound dressing of claim 5 wherein said catalyst is selected from the group consisting of dimethyaminoethanol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, glycerol, trimethylolpropane, pentaerythritol, tolylene-2,4,6-triamine, ethylene diamine, amino-ethanol, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, ethanolamine, diethanolamine, hydrazine, triethanolamine, benzene-1,2,4-tricarboxylic acid, nitrilotriacetic acid, citric acid, 4,4'"'"'-methylenebis (o-chloroaniline), and organic salts of tin and mercury.

7. The wound dressing of claim 6 wherein said cross-linking agent is difunctional or greater with two or more terminal groups reactive with isocyanate residues present on said polyurethane prepolymer.

8. The wound dressing of claim 7 wherein said cross-linking agent is selected from the group consisting of an ethylene glycol/propylene glycol copolymer, silicone polyethylene oxide copolymer, polyethelyeneamines.

14. The wound dressing of claim 4 wherein said polyurethane prepolymer is selected from the group consisting of a polyethyelene glycol diol with available isocyanate groups, a polyoxyethylene diol with available isocyanate groups, a mixture of a polyester and a di-isocyanate, and a mixture of a polyether and a di-isocyanate.

9. A wound dressing material consisting essentially of a nonadherent, thin film, foam polyurethane membrane formed by the reaction of a polyurethane prepolymer with isocyanate residues, a catalyst, and a cross-linking agent with two or more terminal groups reactive with the isocyanate residues, wherein said membrane is formed in the presence of substantial amounts of water to enhance CO₂ formation, and further wherein said membrane exhibits a moisture vapor transmission rate greater than 0.30 grams/inch² / day, said membrane further comprising a substantially smooth surface for application to a wounded area and an insulating region adjacent said smooth surface for maintaining the wound near body temperature.

10. A method for producing a non-adherent, thin film wound dressing material having a substantially smooth surface for application to the wounded area and an insular region adjacent said smooth surface, said method comprising the steps of:

reacting a polyurethane prepolymer having isocyanate residues, a catalyst, and a crosslinking agent with two or more terminal groups capable of reacting with the isocyanate residues, to form a mixture;

placing the mixture on a substrate;

curing the mixture on the substrate in the presence of a substantial amount of water to enhance CO₂ formation to form a membrane with a moisture vapor transmission rate greater than 0.30 grams/inch² /day.

11. The method of claim 10 wherein the mixture is cured at approximately room temperature and at a relative humidity of between 60 to 80%.

12. The method of claim 10 wherein said membrane has a density less than 0.6 grams/centimeter³.

13. The method of claim 10 wherein said membrane exhibits an absorbance based on dry weight of greater than 60%.

15. The method of claim 10 wherein said catalyst is selected from the group consisting of dimethyaminoethanol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, glycerol, trimethylolpropane, pentaerythritol, tolylene-2,4,6-triamine, ethylene diamine, amino-ethanol, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, ethanolamine, diethanolamine, hydrazine, triethanolamine, benzene-1,2,4-tricarboxylic acid, nitrilotriacetic acid, citric acid, 4,4'"'"'-methylenebis (o-chloroaniline), and organic salts of tin and mercury.

16. The method of claim 10 wherein said cross-linking agent is selected from the group consisting of an ethylene glycol/propylene glycol copolymer, silicone polyethylene oxide copolymer, polyethyleneamines.