GB2508134A

GB2508134A - Absorbent dressing having an apertured adhesive layer

Info

Publication number: GB2508134A
Application number: GB201218659A
Authority: GB
Inventors: Graham Steer
Original assignee: FIRST THOUGHT IP Ltd
Current assignee: FIRST THOUGHT IP Ltd
Priority date: 2012-10-17
Filing date: 2012-10-17
Publication date: 2014-05-28
Also published as: GB201218659D0

Abstract

The invention relates to an absorbent dressing 1 comprising an absorbent body 3 with a face 5, at least part of which is intended to overlie a wound, and an adhesive layer 13, 15 which extends over at least a part of that part of the face 5 that overlies the wound. The adhesive layer 13, 15 has a plurality of apertures 17 which extend through the adhesive layer to the absorbent body 3 so that, in use, exudates from the wound can pass through the adhesive layer 13, 15 for absorption by the absorbent body 3. The adhesive layer may be in the form of a grid wherein the apertures are substantially the same size. The adhesive may comprise a plurality of discrete regions with spaces between regions of adhesive. The absorbent body may comprise polyurethane foam and may further comprise a sachet housing an absorbent pad. The absorbent body may comprise a superabsorbent powder and or a humectant.

Description

ABSORBENT DRESSING

Field

This invention relates to absorbent dressings.

Background

In circumstances where an individual, such as a patient, has suffered a trauma or has been wounded, it is often beneficial to cover the wound with an appropriate dressing.

One such previously proposed dressing comprises an absorbent body that has a band of adhesive extending around the periphery of the dressing. This arrangement permits the dressing to be stuck to the body of the patient with an adhesive-free part of the dressing overlying the wound. By covering the wound, it is intended that the dressing should help keep the wound clean, whilst also allowing any exudate from the wound site to be absorbed by the absorbent body.

Whilst this previously proposed dressing can work well, the absorbent body functions best as an absorber of exudate when it is in relatively close contact with the wound site. A problem, however, is that as the dressing is only secured to the patient round the periphery of the dressing, the adhesive-free part of the dressing can tend to move away from the wound site, thereby compromising the efficacy with which exudate is absorbed by the absorbent body.

A further problem is that the adhesive-free part of the dressing can often become stuck to the wound site as the wound heals, and it is not unusual to cause trauma to the patient (for example, to reopen the wound) when the dressing is removed and changed.

It is also the case that as the dressing is only adhered to the patient by a relatively small amount of adhesive around the periphery of the dressing, the adhesive used to adhere the dressing to the patient has to be relatively strong to stop the dressing from becoming detached from the patient. This is unwelcome as it can often be painful to remove the dressing from the patient when it is time to change a used dressing for a fresh one.

The present invention has been devised with the foregoing problems in mind.

Summary of the Invention

One illustrative arrangement that embodies the teachings of the present invention provides an absorbent dressing comprising: an absorbent body having a face, at least part of which is intended to overlie a wound in use; and an adhesive layer extending over at least part of that part of the face that overlies the wound in use, said adhesive layer being configured to define a plurality of apertures that each extend through the adhesive layer to the absorbent body so that, in use, exudate from the wound can pass through the adhesive layer for absorption by the absorbent body.

This arrangement is advantageous in that, by providing an adhesive layer which extends over at least part ot that part of the dressing that overlies the wound, the absorbent body is held in relatively close contact with the wound site, thereby improving the efficacy of exudate absorption by the absorbent body.

Another advantage is that as a relatively larger proportion of the dressing is adhered to the patient, so a weaker adhesive can be employed to retain the dressing on the patient -thereby lessening the potential for pain to be caused to the patient when the dressing is removed.

A yet further advantage of this arrangement is that as the wound site can only bind with the absorbent body through the apertures in the adhesive layer, the potential for damaging any scabs (for example) formed over the wound site when the dressing is removed is reduced. This contrasts with the previously proposed arrangement where the wound can bind with the absorbent body over a much larger area.

Other features, advantages and implementations of the teachings of the invention will be apparent from the following detailed description and the accompanying claims.

Brief Description of the Drawings

Various aspects of the teachings of the present invention, and arrangements embodying those teachings, will hereafter be described by way of illustrative example with reference to the accompanying drawings, in which: Fig. 1 is a schematic representation of the underside (i.e. the side that faces the patient when the dressing is in use) of a dressing that embodies the teachings of the invention; Fig. 2 is a schematic partly-exploded cross-sectional view along the line A-A in Fig. 1; and Fig. 3 is a schematic representation of the underside (i.e. the side that faces the patient when the dressing is in use) of another dressing that also embodies the teachings of the invention; and Fig. 4 is a schematic partly-exploded cross-sectional view along the line A-A in Fig. 3.

Detailed Description

Figs 1 and 2 of the accompanying drawings are schematic depictions of a dressing 1 that embodies the teachings of the present invention. Fig. 2 is a partly exploded cross-sectional view along the line A-A of Fig. 1.

Referring now to Figs. 1 and 2, the dressing 1 comprises a generally rectangular absorbent body 3 that is, in this particular arrangement roughly 3 or 4 mm thick and of polyurethane foam. The absorbent body 3 has a first face 5 that lies adjacent a wound when the dressing is used (hereafter termed the underside), and a second face 7 that faces away from the wound when the dressing is in use (hereafter termed the top side).

In this particular example, both the first and second faces are generally planar, but it will be appreciated that they need not be planar and the dressing could instead be shaped to conform (at least approximately) to the shape of the wound that the dressing is to cover.

For example, if the dressing were intended to cover a wound on the heel of a patient, then the first face 5 may be generally concave and the second face may be generally convex. In other envisaged arrangements, the absorbent body may also be impregnated with a superabsorbent powder (SAP) (such as sodium polyacrylate, for example) and/or a humectant (such as glycerol, for example).

In this particular example the second face 7 is covered by a microporous breathable polyurethane film 9, but it will be appreciated that this film may be omitted or replaced with any other type of breathable film.

The first face 5 is covered with an adhesive layer 11 that extends, in this particular arrangement, over substantially all of the first face of the absorbent body 3.

The adhesive layer is deposited in a pattern on the first face 5 of the absorbent body 3, and the pattern includes a number of apertures that permit exudate to pass from the wound to the absorbent body. In this particular example the adhesive pattern comprises a series of rows 13 and columns 15 that co-operate to form a grid-like adhesive pattern that defines a plurality of apertures 17.

In the particular arrangement shown, the apertures are generally square, but it will be appreciated that they need not have this particular shape. The apertures could, instead, be circular or indeed any other shape. Similarly, whilst in the particular arrangement shown the apertures are in a regular pattern, this need not be the case.

The apertures could, for example be smaller or larger, or closer or further apart, in some parts of the dressing as compared with others. It is also not essential for all the apertures to be the same shape, as a pattern consisting of a mix of different shapes could instead be provided.

In the particular arrangement depicted in Fig. 1, the dressing is roughly 100 mm by 120 mm and each aperture has an area of roughly 3 to 4 mm2. The pattern depicted includes approximately 800 apertures, and thus the area of the bandage that is free from adhesive constitutes approximately 20 to 26% of the area of that part of the first face over which the adhesive layer extends. In general terms it is preferred for the area free from adhesive to constitute between 10 to 40%, more preferably 15 to 30%, and more preferably 20 to 28% of the area of that part of the first face over which the adhesive layer extends.

In another envisaged implementation of the invention, the adhesive layer may comprise a series of discrete regions of adhesive, with each said region being spaced from the neighbouring regions (to allow exudate to pass from the wound into the adsorbent body). For example, in this embodiment the "apertures" depicted in Fig. 1 could comprise discrete regions of adhesive, and in this case the area free from adhesive would be a much larger proportion of the area of the first face over which the adhesive layer extends, in this particular case from 70 to 80% of the area of the first face over which the adhesive layer extends. In other envisaged arrangements the area of the first face that is free from adhesive may comprise 60 to 80%, preferably 65 to 70% of the area of the first face over which the adhesive layer extends.

As will be appreciated by persons skilled in the art, the area of the first face that is free from adhesive will tend to determine the rate at which exudate may be absorbed from the wound over which the dressing is place. An increase of the adhesive free proportion will tend to increase the rate at which exudate is absorbed, and vice versa.

Thus a skilled person may construct dressings having appropriate rates of absorption for observed rates of exudate production.

Varying the adhesive free area will also affect the ease with which the dressing may be removed from the patient, and thus it may be beneficial for dressings with a larger adhesive free area to include stronger adhesives than a dressing with a smaller adhesive free area.

A variety of different adhesives are known to persons of ordinary skill in the art, and a skilled person will readily be able to select an appropriate adhesive for the task that the particular dressing being constructed is envisaged to accomplish. In one particularly preferred implementation, the adhesive layer may be a so-called SEBS (Styrene Ethylene Butadiene Styrene) adhesive. SEBS is preferred as an adhesive as it is relatively low tack, and as it doesn't include silicone it is easier to manufacture.

In the particular implementation depicted in Figs. 1 and 2, the adhesive layer is covered by a so-called butterfly-fold release liner 19, for example a siliconised release liner. Bi-fold release liners, as is well known in the art, consist of two liner sections. One section 190) is folded over and the other section 19(u) overlaps the other. A user can grasp the overlapping part 19(u) to remove that part of the liner, and then grasp the folded part of the other section 190) of the liner to remove that part. Once the liner has been removed, the dressing may be adhered to a patient.

Whilst bi-fold liners are preferred, it will be appreciated by persons of ordinary skill in the art that any type of release liner may instead be employed. For example, the release liner could comprise a single sheet that extends over at least that part of the dressing over which the adhesive layer extends.

The dressing described above with reference to Figs. 1 and 2 may be manufactured in a variety of different ways. In one envisaged arrangement an appropriately patterned gravure may be employed to deposit an adhesive pattern onto a so-called differential double sided release liner. The adhesive layer on the liner is then brought into contact with absorbent foam body to transfer the adhesive onto the foam (heat may be applied to aid this part of the process), and once the adhesive layer has been transferred to the foam the sacrificial double sided release liner is removed and discarded. A new butterfly-fold release layer is then applied to the adhesive layer, following which individual dressings may be stamped out. In one envisaged implementation the liners and foam may be fed from reels so that the manufacturing process can operate virtually continuously. In circumstances where the dressing is to have a single sheet release liner (instead of a butterfly-fold liner), the process steps involving removal of the double-sided release liner and replacement of that liner with a butterfly-fold liner can be omitted.

Figs. 3 and 4 of the accompanying drawings are schematic depictions of another dressing 21 (of the same size as that depicted in Figs. 1 and 2) that embodies the teachings of the present invention. Fig. 4 is a partly exploded cross-sectional view along the line B-B of Fig. 3. Common features of the dressings shown in Figs. 1 and 3 have been denoted with the same reference numeral.

The absorbent body 3 of the dressing 21 comprises, in this illustrative example, a superabsorbent sachet rather than polyurethane foam (as in the dressing depicted in Fig. 1). The absorbent body comprises, in this particular arrangement, an absorbent or superabsorbent pad 23 that is sandwiched between first and second non-woven sheets 25, 27 (which may comprise, for example, 30 gsm PE/PET (Polyester/Polyethylene) BiCo (bi-component) sheets), and retained between the non-woven sheets by means of a peripheral weld 29. In one illustrative implementation the pad may comprise an airlaid SAF (superabsorbent fibre) which may be combined, in various suitable mixes or ratios known to persons of ordinary skill in the art, with cellulose fibres and/or bicomponent (BiCo) with or without an additional superabsorbent powder (SAP) (such as sodium polyacrylate, for example) and/or a humectant (such as glycerol, for example).

As with the dressing 1 of Fig. 1, an adhesive layer 11, 13, 15 is provided on one face of the absorbent body 3, and that adhesive layer can have any of the features (desciibed above) of the adhesive layer of the dressing shown in Fig. 1. A release layer 19 is provided over the adhesive layer 11. The release layer may comprise, as depicted, a two part butterfly-fold release layer, or in another arrangement a single sheet release layer. A two-part butterfly-fold release layer is preferred as it tends to be easier to remove than a single sheet, The dressing depicted in Figs 3 and 4 may be manufactured in any of a number of different ways. In one illustrative arrangement, an appropriately patterned gravure may be employed to deposit a patterned adhesive layer directly onto the non-woven sheet of a preformed absorbent body (heat may be applied to assist adhesion of the adhesive to the absorbent body), and then a release layer is provided over the adhesive layer.

In another illustrative arrangement, the dressing may be manufactured in-situ from its constituent components. In this arrangement a gravure is employed to deposit a patterned adhesive layer 13, 15 onto a sacrificial double-sided release layer. Once the patterned adhesive layer has been formed on the release layer, a non-woven sheet 27 is coupled to the adhesive layer. Next, individual pads 23 are laid up on the non-woven that is coupled to the adhesive layer, following which a second non-woven sheet 25 is placed over the pads 23. The non-woven sheets are then welded to one another (along weld line 29 -Fig. 3) to enclose each pad between two sheets of non-woven. Next, the sacrificial release layer is removed, and a new butterfly-fold release layer is applied to the adhesive layer. Finally, the individual dressings may then be chopped or pressed out along line 31. Advantageously, as the line 31 lies outside of the weld 29, the dressings tend to have much softer peripheral edges than if line 31 were to lie along the weld line 29, and hence are more comfortable for patients to use.

It will be appreciated that whilst various aspects and embodiments of the present invention have heretofore been described, the scope of the present invention is not limited to the particular arrangements set out herein and instead extends to encompass all arrangements, and modifications and alterations thereto, which fall within the scope of the appended claims.

For example, whilst in the particular implementations described above, the dressings each have an adhesive layer that extends over substantially all of the face of the dressing that is adhered to the patient, it will be appreciated and should be noted that this is not an essential feature of the invention, and that the adhesive layer may instead extend over only a part of the face of the dressing that is to be adhered to the patient. Advantageously, such arrangements could be employed to provide a flange or other part of the dressing that is not adhered to the patient, which flange or pad could be used to facilitate removal of the diessing from the patient.

It will also be understood that whilst the particulai dressings described above have a regular grid-like layer of adhesive, this is not an essential feature of the invention.

The adhesive may extend over the absorbent body in any desired paftern, so long as the layer of adhesive includes a plurality of apertures that provide a path for exudate to travel from the wound to the absorbent body. It is also envisaged that the dressing may infused with a medicament, oi an anaesthetic ci antiseptic substance to piomote healing and/or well being of the patient.

It will also be appreciated that the scope of the present invention is not limited to dressings that include any particular type of absoibent body. Rathei, the scope of the present invention includes all types of absorbent bodies, including foams, rriircrofibre bodies and so-called superabsorbent bodies.

Lastly, it should also be noted that whilst the accompanying claims set out particulai combinations of features described herein, the scope of the present invention is not limited to the particular combinations heieafter claimed, but instead extends to encompass any combination of features herein disclosed.

Claims

CLAIMS1. An absorbent dressing comprising: an absorbent body having a face, at least part of which is intended to overlie a wound in use; and an adhesive layer extending over at least a part of that part of the face that overlies the wound in use, said adhesive layer being configured to define a plurality of apertures that each extend through the adhesive layer to the absorbent body so that, in use, exudate from the wound can pass through the adhesive layer for absorption by the absorbent body.
2. A dressing according to Claim 1, wherein said adhesive layer is configured to provide a regular array of apertures.
3. A dressing according to Claim 2, wherein said adhesive layer comprises a grid of adhesive.
4. A dressing according to any preceding claim, wherein said apertures are, at least approximately, all of the same size.
5. A dressing according to any preceding claim, wherein said apertures cooperate to provide a region of the dressing that is substantially free from adhesive, said region constituting approximately 10 to 40% of the area of the face over which the adhesive layer extends.
6. A dressing according to Claim 5, wherein said apertures cooperate to provide a region of the dressing that is substantially free from adhesive, said region constituting 15 to 30% of the area of the face over which the adhesive layer extends.
7. A dressing according to Claim 6, wherein said apertures cooperate to provide a region of the dressing that is substantially free from adhesive, said region constituting 20 to 20% of the area of the face over which the adhesive layer extends.
8 A dressing according to any preceding claim, wherein each aperture has an area of approximate 3-4 mm2.
9. A dressing according to Claim 1, wherein said adhesive layer comprises a plurality of discrete regions of adhesive, said apertures comprising spaces between adjacent regions of adhesive.
10. A dressing according to Claim 9, wherein said discrete regions of adhesive are provided in a regular array.
11. A dressing according to Claim 9 or 10, wherein said apertures co-operate to provide a region of the dressing that is substantially tree from adhesive, said region constituting 60 to 80% of the area of the face over which the adhesive layer extends.
12. A dressing according to any preceding claim, wherein said absorbent body comprises an absorbent foam.
13. A dressing according to Claim 12, wherein said foam is of polyurethane.
14. A dressing according to any of Claims 1 to 11, wherein said absorbent body complises a sachet housing an absorbent pad.
15. A dressing according to Claim 14, wherein said absorbent pad comprises a pad of airlaid SAF, which SAF fibres may optionally be combined with cellulose fibres and/or bicomponent.
16. A dressing according to any of Claims 12 to 15, wherein said absorbent body further comprises a superabsorbent powder and/or a humectant.
17. A dressing according to any preceding claim, wherein said adhesive layer extends over a major part of that part of the face that overlies the wound in use.
18. A dressing according to any preceding claim, wherein said adhesive layer extends over substantially all of said adhesive body face.
19. A dressing according to any preceding claim, wherein the absorbent body is infused or otherwise comprises a medicament, or an anaesthetic or antiseptic substance.
20. A dressing according to any preceding claim, wherein the adhesive layer is of SEBS.
21. A dressing according to any preceding claim, further comprising a release layer coupled to said adhesive layer.
22. A dressing according to Claim 21, wherein said release layer comprises a two-part butterfly-fold release layer.
23. An absorbent dressing substantially as hereinbefore described and/or as shown in Figs. 1 and 2, or Figs. 3 and 4 of the accompanying drawings.