Smith and Nephew Associated Companies P.l.c.

David A Rawlings

William D Potter

An adhesive dressing for use on moist wounds which comprises a pressure sensitive adhesive-coated wound contacting first layer in which there are present holes capable of transmitting liquid water and a moisture vapor permeable, continuous film. The continuous film is attached to the first layer in such a way as to form a reservoir into which water can pass through the holes in the first layer and can evaporate from the reservoir through the continuous film. The adhesive coated first layer has a moisture vapor permeability of less than 300 gm.sup.-2 24 hr.sup.-1 at 37.degree. C. and 100% to 10% relative humidity difference and the continuous film has a moisture vapor permeability which is greater when in contact with liquid water than when not in contact with liquid water. Optionally, an intermediate water transmitting layer may be present between the first layer and the continuous film.

Surgical dressing

A surgical dressing is described which consists essentially of a film which carries an adhesive layer for securing the dressing to the body characterized in that (a) the film is continuous and comprises a polymer which in contact with water has a higher MVP than when in contact with moisture vapor but not water; (b) the adhesive layer is adapted to allow access of water to the film when water is in contact with the adhesive layer so that (c) the surgical dressing has an MVP of not less than 2500 g/m.sup.2 when the adhesive layer is in contact with water and has an MVP of not more than 2000 g/m.sup.2 when the adhesive is in contact with moisture vapor but not water; whereby the dressing is suitable for use on exuding wounds and on non-exuding wounds.

Surgical adhesive dressing

A surgical dressing which consists essentially of a film which carries an adhesive layer for securing the dressing to the body characterized in that (a) the film is continuous and comprises a polymer which in contact with water has a higher MVP than when in contact with moisture vapor but not water, (b) the adhesive layer is adapted to allow access of water to the film when water is in contact with the adhesive layer so that said surgical dressing has a MVP of not less than 2500 g/m.sup.2 when the adhesive layer is in contact with water and has a MVP of not more than 2000 g/m.sup.2 when the adhesive is in contact with moisture vapor but not water; whereby the dressing is suitable for use on exuding wounds and on non-exuding wounds.

A moisture vapor permeable, adhesive surgical dressing is described which comprises a continuous film of a hydrophilic polymer which has a moisture vapor permeability which is greater when in contact with water than when not in contact with water and which is attached around its edges to a water transmitting film so as to form a sealed portion into which exudate may pass from an exuding wound. The water transmitting film comprises a backing layer and an adhesive layer on the side remote from the continuous film. The adhesive layer is suitable for adhering the dressing to the skin. The water transmitting film allows or is adapted to allow access of water to the film when in contact with water so that when used on an exuding wound the high moisture vapor permeability of the continuous film allows water to evaporate through the dressing and prevents the dressing forming a blister. The low moisture vapor permeability of the film when not in contact with water makes the dressing suitable for use on non-exuding wounds. Preferably a second water transmitting film is present between the continuous film and the water transmitting layer.

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Stansted Mountfitchet, United Kingdom

David A Rawlings