US4452845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moisture vapor transmitting film of polyurethane blended with an incompatible polymer
Assignee: Smith and Nephew PLC
•
Filing: 1983-07-12
•
Granted: 1984-06-05
•
Expires: 2003-07-12
Abstract
Abstract A moisture vapor transmitting film comprising a blend of polyurethane and an incompatible polymer characterized in that the incompatible polymer forms a discrete phase within a continuous matrix of polyurethane and that said film contains voids and processes for the manufacture thereof.
Inventors
- 👤 Ronald Lloyd
- 👤 Peter J. Metcalfe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:05
CPC Classifications
A; A61; A61L; A61L15/00; A61L15/16; A61L15/22; A61L15/225; C; C08; C08L; C08L75/00; C08L75/04; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978; Y10T428/249979; Y10T428/249982; Y10T428/249983; Y10T428/249985; Y10T428/26; Y10T428/268; Y10T428/28
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
56 words
A moisture vapour transmitting elastomeric film which does not contain openings or passages which provide a continuous pathway through the film and is impermeable to liquid water comprising a blend of polyurethane and an incompatible polymer wherein the incompatible polymer forms a discrete particulate phase within a continuous matrix of polyurethane and the film contains voids.
Claim 2
Dependent Claim
56 words
A moisture vapour transmitting elastomeric film which does not contain openings or passages which provide a continuous pathway through the film and is impermeable to liquid water comprising a blend of polyurethane and an incompatible polymer wherein the incompatible polymer forms a discrete particulate phase within a continuous matrix of polyurethane and the film contains voids.
Claim 3
Dependent Claim
51 words
A moisture vapour transmitting elastomeric film which does not contain openings or passages which provide a continuous pathway through the film and is impermeable to liquid water comprising a blend of polyurethane and a discrete particulate phase wherein the discrete particulate phase comprises an incompatible polymer and the film contains voids.
Claim 4
Dependent Claim
51 words
A moisture vapour transmitting elastomeric film which does not contain openings or passages which provide a continuous pathway through the film and is impermeable to liquid water comprising a blend of polyurethane and a discrete particulate phase wherein the discrete particulate phase comprises an incompatible polymer and the film contains voids.
Claim 5
Dependent Claim
19 words
A film according to claim 1 in which the voids have a diameter of 2 microns to 12 microns.
Claim 6
Dependent Claim
32 words
A film according to claim 1 in which the film has a moisture vapour transmission rate of at least 350 g/m 2 /24 hours at 37° C. at 100%-10% relative humidity difference.
Claim 7
Dependent Claim
19 words
A film according to claim 1 in which the film has a thickness of 0.0125 mm to 0.125 mm.
Claim 8
Dependent Claim
19 words
A film according to claim 1 in which the polyurethane comprises 50% to 80% by weight of the film.
Claim 9
Dependent Claim
15 words
A film according to claim 1 in which the incompatible polymer comprises high impact polystyrene.
Claim 10
Dependent Claim
19 words
A film according to claim 1 in which the incompatible polymer comprises a low density polyethylene containing inorganic filler.
Claim 11
Dependent Claim
13 words
A film according to claim 1 in the form of a medical dressing.
Claim 12
Dependent Claim
15 words
A medical dressing according to claim 9 wherein one surface is coated with an adhesive.
Claim 13
Dependent Claim
14 words
A film according to claim 1 in which the polyurethane is a linear polyurethane.
Claim 14
Dependent Claim
24 words
A film according to claim 11 in which the polyurethane is a linear polyurethane which comprises 45% to 85% of the film by weight.
Claim 15
Dependent Claim
27 words
A film according to claim 6 in which the incompatible polymer comprises a vinyl polymer in the form of discrete particles of diameter 2 to 5 microns.
Claim 16
Dependent Claim
13 words
A film according to claim 13 in which the vinyl polymer is polystyrene.
Claim 17
Dependent Claim
14 words
A film according to claim 13 in which the vinyl polymer is a polyethylene.
Claim 18
Dependent Claim
42 words
A medical dressing according to claim 10 in which the adhesive is moisture vapour transmitting and the dressing has a moisture vapour transmission rate of at least 500 g/m 2 /24 hours at 37° C. at 100% to 10% relative humidity difference.
Claim 19
Dependent Claim
19 words
A medical dressing according to claim 10 in which the adhesive is continuous and 12.5 to 75 microns thick.
Claim 20
Dependent Claim
16 words
A medical dressing according to claim 17 in which the adhesive comprises an acrylate ester polyer.
Claim 21
Dependent Claim
22 words
A film according to claim 1 in which the blend of polyurethane and an incompatible polymer is formed under hot melt conditions.
Claim 22
Dependent Claim
11 words
A film according to claim 1 formed by hot melt extrusion.
Claim 23
Dependent Claim
20 words
A film according to claim 20 in which the film is stretch oriented in direction transverse to its extrusion direction.
Claim 24
Dependent Claim
19 words
A film according to claim 1 in which the film has a recoverable elastic strain of at least 150%.
Claim 25
Dependent Claim
74 words
A moisture vapour transmitting elastomeric film from 0.075 mm to 0.125 mm thick which does not contain openings or passages which provide a continuous pathway through the film and is impermeable to liquid water and which comprises a blend of polyurethane and an incompatible polymer in which film the incompatible polymer forms a discrete particulate phase within a continuous matrix of polyurethane and which film contains voids of diameter 2 microns to 12 microns.
Claim 26
Dependent Claim
74 words
A moisture vapour transmitting elastomeric film from 0.075 mm to 0.125 mm thick which does not contain openings or passages which provide a continuous pathway through the film and is impermeable to liquid water and which comprises a blend of polyurethane and an incompatible polymer in which film the incompatible polymer forms a discrete particulate phase within a continuous matrix of polyurethane and which film contains voids of diameter 2 microns to 12 microns.
Claim 27
Dependent Claim
16 words
A film according to claim 23 which contains voids of diameter 3 microns to 6 microns.
Claim 28
Dependent Claim
28 words
A film according to claim 23 in which the polyurethane is a linear polyurethane which comprises 45% to 85% of the blend and the incompatible polymer is polyethylene.
Claim 29
Dependent Claim
28 words
A film according to claim 23 in which the polyurethane is a linear polyurethane which comprises 45% to 85% of the blend and the incompatible polymer is polystyrene.
Claim 30
Dependent Claim
14 words
A film according to claim 26 in which the polystyrene is rubber modified polystyrene.
Claim 31
Dependent Claim
22 words
A medical dressing for adhering to skin which comprises a film according to claim 23 and an adhesive on one surface thereon.
Claim 32
Dependent Claim
13 words
A film according to claim 24 in the form of a medical dressing.
Claim 33
Dependent Claim
13 words
A film according to claim 25 in the form of a medical dressing.
Claim 34
Dependent Claim
13 words
A film according to claim 26 in the form of a medical dressing.
Claim 35
Dependent Claim
13 words
A film according to claim 27 in the form of a medical dressing.
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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) | 1987-06-05 | 1987-12-05 | 1988-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-05 | 1991-12-05 | 1992-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-05 | 1995-12-05 | 1996-06-05 | $7700.00 | Window Closed / Lapsed |