Wound dressings having low adherency
First Claim
1. A wound dressing comprising:
- an absorbent layer;
an envelope formed from thermoplastic film enclosing said absorbent layer wherein the film has a textured performed surface on a front side of said envelope and a smoothed perforated surface on a rear side of said envelope;
a semipermeable backing sheet covering said rear side of said envelope and extending outwardly therefrom; and
a layer of adhesive on said backing sheet adjacent to said rear side of said envelope and bonding said envelope to said backing sheet.
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Accused Products
Abstract
The invention provides wound dressings, in particular wound dressings of low- or non-exuding wounds a bleeding wounds. The wound dressings are of the island type, having as adhesive-coated backing sheet (6) and an absorbent island (9) supported on the backing sheet. The island (9) comprises a layer (2) of liquid absorbent material enclosed in an envelope of textured perforated thermoplastic film. The film (3) at one side of the island (9) presents a ribbed or embossed perforated surface having low adherency to the wound. The film island an the rear surface of the envelope is perforated and smoothed to provide good attachment to the backing sheet (6) and controlled water vapor transmission rate. The invention also provides a method of manufacture of the wound dressings according to the invention, according to which the absorbent layer (2) is wrapped in a textured perforated thermoplastic film, and the film on the rear face of the envelope is then preferably smoothed by blowing hot air onto it.
135 Citations
31 Claims
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1. A wound dressing comprising:
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an absorbent layer;
an envelope formed from thermoplastic film enclosing said absorbent layer wherein the film has a textured performed surface on a front side of said envelope and a smoothed perforated surface on a rear side of said envelope;
a semipermeable backing sheet covering said rear side of said envelope and extending outwardly therefrom; and
a layer of adhesive on said backing sheet adjacent to said rear side of said envelope and bonding said envelope to said backing sheet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A process for the production of a wound dressing comprising the steps of:
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providing a layer of absorbent material;
wrapping said layer in an envelope of a textured perforated thermoplastic film;
followed bysmoothing said thermoplastic film on one side of said envelope; and
applying an adhesive-coated backing sheet onto said smoothed thermoplastic film on said one side of said envelope. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
a conveyor for conveying a layer of absorbent material enclosed between two layers of perforated textured thermoplastic film;
a hot air blower configured to blow hot air onto one of said layers of thermoplastic film to soften and flatten said one of said layers thereby smoothing said one of said layers;
a temperature sensor to measure the temperature of the said one of said layers adjacent to said hot air blower; and
control means connected to said temperature sensor to regulate said conveyor and/or said hot air blower in response to signals from said temperature sensor.
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27. An apparatus according to claim 26, wherein said temperature sensor is an infrared radiation detector.
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28. An apparatus according to claim 26, wherein said hot air blower is adapted to blow hot air at a temperature between the softening temperature of the thermoplastic film and the melting temperature the thermoplastic film.
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29. An apparatus according to claim 28, wherein said thermoplastic film is an ethylene methyl acrylate film and said hot air blower is adapted to blow hot air at a temperature between 110°
- C. and 160°
C.
- C. and 160°
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30. A process according to claim 21, further comprising the step of cutting said envelope into lengths prior to applying said adhesive-coated backing sheet.
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31. A process according to claim 26, further comprising a step of cooling said envelope intermediate said smoothing and said cutting steps.
Specification