GB2192792A - Wound dressing - Google Patents

Description

GB2192792A 1 SPECIFICATION wound dressing which consists essentially of a

central area which is adhesive free and is Wound dressing manufacture and use non-adherent to wounds and which is a layer of polymer, an optional absorbent layer at the The present invention relates to a wound 70 non-wound facing side of the central area and dressing which consists essentially of an ad- handling areas outwardly disposed from said hesive-free central area which is non-adherent central area which handling areas have pres to wounds and which is formed from a layer sure sensitive adhesive areas covered by re of synthetic polymer and adhesive coated movable protectors.

handling areas outwardly disposed from the 75 By 'consists essentially of' when used central area, the adhesive surfaces of these herein means that the dressing consists of the handling areas being covered by removable elements named but does not exclude the protectors. Optionally an absorbent layer is presence of any temporary or removable ele present at the non-wound facing side of the ments which do not form part of the dressing central area. The present invention also relates 80 in use or elements which are not necessary to the manufacture and use of these dress- for the function of the dressing.

ings. By 'adhesive free' it is meant that there is Wounds such as burns, donor sites, surgical no adhesive present on the wound contacting incisions and the like can present a serious surface of the central area, but does not ex problem for their treatment by producing large 85 clude the possibility of the presence of adhe amounts of exudate which can cause some sive on the non-wound contacting surface for conventional dressings to become saturated or example for adhering an absorbent layer in to adhere to the wound. One approach to contact with the central area.

solving this problem is to employ materials By layer is meant a film per se or a combi which are designed to reduce the propensity 90 nation of two or more films.

to adhere to the wound. Such dressings are Aptly the handling areas may be provided at disclosed in, for example, United States Pa- one edge of the central area, two opposite tents Nos. 2923298 abd 3543750 and British edges of the central area, three edges of the Patent No. 778813 and European Patent Nos. central area or around the periphery of the 50514 and 122085. However, an unexpected 95 central area. It is clear therefore that the disadvantage arising from the success of such dressings of the invention will have at least non-adherent dressings is that on application one handling area.

and during use the dressings tend to slip Aptly the handling areas may comprise ad across the surface of the wound thereby dis- hesive coated tape attached to one edge, to turbing the wound surface or the healing 100 two opposite edges, to three edges or around wound. the periphery of the central area. Suitably the Conventionally non-adherent dressings are handling areas will extend over two opposite applied by placing the dressing in contact with side edges of the central area. It is clear the wound and then keeping the dressing in therefore that the dressings of the invention place by application of bandages or, in the 105 will have at least one adhesive coated hand case of absorbent dressings, lengths of adhe- ling area.

sive surgical tape can be used. Usually the It is clear therefore that the present inven lengths of surgical tape are cut from a roll of tion provides a wound dressing which con tape and. adhered by one end from a vertical sists essentially of a central area and at least surface until required, The disadvantages of 110 one handling area outwardly disposed from this procedure are that the tape will be ex- said central area, which central area is adhe posed to air borne contamination and may ad- sive free and is non- adherent to woijnds and here to the surface. It has now been found which comprises a layer of polymer and in that by providing non-adherent and adhesive- which at least one of said handling areas have free wound dressings with adhesive coated 115 a pressure sensitive adhesive area covered by handling areas the above disadvantages maybe a removable protector.

avoided. The dressings have been found to be Preferably the wound dressing has two easier to manipulate during applications to the handling areas present at two opposite edges patient because of the rigidity provided by the of the central area.

handling areas. There is less risk of contami- 120 Favourably the adhesive coated tape may be nation of the wound contacting surface of the arranged so that part of the tape is attached dressing by the person applying it as the to the polymer film and the remainder of the dressing will be held by the handles. The pro- tape projects beyond the central area to leave tector may be removed from one handling an exposed adhesive coated surface which area and the dressing anchored to the skin 125 maybe covered by a removable protector.

prior to completing the application. The hand- The material which may be used to form ling areas when all the protectors are removed the handling areas of the wound dressing of will serve to hold the dressing in place on the the present invention include any of those ma skin. terials described as suitable for handles in Accordingly the present invention provides a 130 European Patent Application No. 161865 at 2 GB2192792A 2 page 11 line 4 to page 13 line 23, which is coated handling areas prior to use will have incorporated herein by cross-reference. their exposed adhesive area covered by remo

Particularly preferred materials for forming vable protectors. Suitable protectors include the handling areas are integral nets particularly silicone release coated papers, plastics coated those formed by the fibrillation of thermoplas- 70 papers and release coated films such as sili tic embossed polyolefin films comprising low cone coated polyethylene. A favoured release and high density polyethylene, polypropylene protector is a silicone/polyethylene coated pa or copolymers or blends thereof for example per known as Steralease (Trade mark).

blends of polyolefin with polystyrene. Such The protectors may be arranged to cover nets and the polymers used for forming them 75 only the exposed adhesive coating on the are described in for example British Patents handling area or may be adapted to cover also Nos. 1495151 and 1531715. the central area. In one preferred arrangement Suitable handling areas may also be made a single protector covers the central area and from a wide variety of materials including pa- two further protectors are present on the per, non-woven fabric, woven fabric and films, 80 handling areas. Another form of three part sheets or webs of polymers including polyproprotector is illustrated in for example European pylene, polyethylene, copolymers thereof and Patent Application No. 117632.

blends thereof, polyesters and porous polyvi- In a second preferred arrangement a protec nyl chloride. Preferred handling areas may be tor covers the exposed adhesive coating on made from paper, porous polyvinyl chloride 85 one handling area and a second protector is (Porvic, trade mark) or microporous films such then adapted to cover both the central area of as Micropore (trade mark). the dressing and the exposed adhesive coat Suitably the handling areas may be from ing on the second handling area. This may be 1.Ocm to 4.Ocm in width and preferably 1.5 achieved by folding the second protector long- to 2.5cm in width, for example 2.Ocm, 2.5cm 90 itudinally near to one edge so that the release or 3.Ocm in width. The width of the margin of coated surface can be brought into contact the. handling areas which is adhered to the with the exposed adhesive surface of the sec edge of the dressing is suitably 0.5 to 1.Ocm ond handling means as well as the central and preferably is 0.7 to 1.0cm. area of the dressing. In use the first adhesive Since the handling area is usually to be ad- 95 coated handling area is adhered to the skin, hered to the skin, it is apt that the adhesive- then the second protector may be peeled coated handling area should have a moisture back until the central area is completely unco vapour transmission rate of at last 250gm- 2 vered and the protector is unfolded. The pro 24hr- 1 at 37'C and 100% to 10% relative tector is then still attached to the dressing by humidity difference when measured by the Pa- 100 means of the second handling area. Since the yne Cup Method. More suitably the adhesive adhesive at this attachment is now under coated handling area should have a moisture shear force, a slight tension may be applied to vapour transmission rate of at least 450grn 2 the dressing by pulling the protector against 24hr-1 and preferably should be at least the anchorage of the first handling area with- 6009m-2 24hr-1. The handling area may 105 out the protector separating from the handling therefore be adhered to the skin, without the area. This tension results in a dressing which risk of causing maceration to the underlying contains slits, in the slits opening slightly normal healthy skin. which results in a better performance from the Suitable adhesives for use on the handling dressing. The second protector may be re- areas are described in for example British Pa- 110 moved by peeling from the handling area and tent No. 1280631 and European Patent No. the handling area may then be adhered to the 35399. A particularly suitable adhesive is an skin. Alternatively it may be the second hand acrylate ester copolymer adhesive formed ling area which is folded longitudinally around from the polymerisation of 47 parts 2-ethyl- the edge of the dressing and attached to the hexyl acrylate, 47 parts butyl acrylate and 6 115 non-dressing contacting side of the second parts acrylic acid. This adhesive in combina- protector. The protector is therefore preferably tion with a net gives a handling area having a formed from a material which has a release particularly suitable moisture vapour transmis- coat on both surfaces. The operation of the sion rate. A second suitable adhesive is a po- dressing is similar to that above.

lyvinyl alkyl ether adhesive such as polyvinyl 120 In a third preferred arrangement the protec ethyl ether adhesive. tor is in the form of a split protector in which The adhesive of the coating on the handling the two halves overlap in the central area of - areas may be present as a continuous layer or the dressing and which cover the central area as a non-continuous layer for example a pat- of the dressing and the exposed adhesive sur- tern spread layer, a microporous layer or a 125 faces of the handling areas. Suitably each pro porous layer. tector will have a longitudinal fold as de Suitably the adhesive layer will be 15 to scribed above or the handling area will have a 65ym thick and will generally have a weight longitudinal fold.

per unit area of 10 to 75gm-2. In another aspect the present invention pro- As mentioned hereinabove, the adhesive 130 vides a wound dressing which consists essen- 3 GB2192792A 3 tially of a central area which is adhesive free securely fastened to the patient after applica and is non-adherent to wounds and which is a tion. Aptly the apertured film used in the pre layer of polymer, an optional absorbent layer sent invention may be any of those which at the non-wound facing side of the central have been used as a non- adherent wound area and handling areas outwardly disposed 70 contact layer heretofore, for example films from said central area which handling areas formed from polyethylene, poiyfluorocarbons have pressure sensitive adhesive areas cov- and the like. However, preferred materials for ered by removable protectors and in which at forming the apertured wound contact layer in least one of said protectors is adapted to clude those describe in European Patent Appli- cover the central area of the dressing as well 75 cation No. 122085 at page 6 line 3 to page as the adhesive coating on the handling area. 13 line 11, which are incorporated herein by Preferably the protector is in the form of a cross-reference. Suitably therefore the wound split protector whereby each protector on the contact layer comprises a conformable film handling means is adapted to cover a part of with apertures in the form of slits therethe central area of the dressing and the adhe- 80 through in which the film comprises a first sive coating of the handling area. The proteclayer for contacting the wound laminated to a tors overlap within the central area of the second layer, said first layer comprising a ma dressing. terial which when in contact with water swells If an absorbent layer is absent in the dress- and said second layer comprises a material ing of the invention then a support frame such 85 which when in contact with water does not as that described in European Patent Applica- swell or swells less than the first layer. Thus tion No. 51935 may be present on the non- when in contact with a wet wound the slits wound contacting surface of the central area. open allowing water to pass through the film The central area of the dressings of the pre- and when in contact with a dry surface the sent invention comprises a synthetic polymer 90 slits are closed.

layer. In one preferred form the central area A preferred apertured film wound contact will be a film. layer is formed from a laminate of a hydro The central area may be a continuous film philic polyurethane, whose preparation is de such as a moisture vapour permeable film in- scribed in British Patent No. 2093190B and cluding those formed from polyurethane, poly- 95 which will contain from 20 to 40% by weight vinyl alcohol, cellulose derivatives, elastomeric of water when hydrated and a styrene-butadi polyester such as Hytrel (Trade Mark), poly- ene-triblock copolymer. Aptly this laminate ether polyamide such as, Pebax (Trade Mark) may be apertured by cutting slits through the and the like. Suitably the film may have a laminate. Normally the slits will be arranged in moisture vapour transmission rate of greater 100 rows and often in rows in which the slits of than 2509m-2 24hr1 at 37'C and 100% to any one row will be staggered from those in 10% relative humidity difference and more the next row. Suitably the slits will be from 1 suitably greater than 5009m-2 24hr--', most to 15mm long and more suitably 2 to 1Omm suitably greater than 10009M-2 24hr-1 and long. The slits in any row may be suitably preferably greater than 180Ogrn-2 24hr-1. 105 from 2 to 1Omm apart and the distance be In one preferred form the central area comtween the slits in adjacent rows may suitably prises a continuous film of a hydrophilic poly- be 1 to 15mm, suitably 3 to 1Omm and pre mer and in particular of a hydrophilic polyure- ferably 4 to 8mm.

thane. Suitable polyurethanes may contain A second preferred central area wound con when hydrated from 5 to 95% by weight of 110 tacting layer comprises a perforated polyester water, more suitably 15 to 60% by weight of film. Suitable perforated polyester films are water and preferably from 20 to 40% by described in United States Patents os.

weight of water for example 25%, 30% or 2923298, 3012659 and 3012918.

40%. Preferred hydrophilic polyurethanes are An apt central area wound contacting, layer described in United Kingdom Patent No. 115 comprises a net material. Preferred nets are 2093190B, expecially in Example 2. described in United Kingdom Patent No.

However in a second preferred form the 1548865 which is incorporated by cross-refer central area may be an apertured film. It has ence. A particularly preferred net is described been found to be particularly advantageous to in Example 2 of that patent.

use outwardly disposed handling areas in 120 A second suitable net may be formed from dressings which employ an adhesive-free aper- an elastomeric polymeric material such as tured film wound contact layer. Non-adherent polyurethane or a blend of ethylene-vinyl ace dressings in which apertured polymer films are tate and polyolefin such as polystyrene. Such used as the wound contact layer may suffer nets are described in for example European from the disadvantage that they may slide 125 Patents Nos. 50514 and 141592.

over the wound during and after application Another apt form of the central area is an thereby disturbing the wound or more diliteri- open knit fabric whose construction allows ex ously the healing wound. By using adhesive udate to pass freely from the wound but does coated handling areas the dressing may be not adhere the wound. The fabric may be anchored at one end during application and be 130 made from rayon filaments.

4 GB2192792A 4 The wound dressings of the present inven- dressings of the desired length. Suitably the tion may or may not include an absorbent dressings may be from 5 x 5cm to 20 x 20cm layer at the non-wound facing side of the cen- in size.

tral area. If an absorbent layer is not present The wound dressing of the invention is pre then it is conventional to place an absorbent 70 ferably sterile. The wound dressing is there layer in contact with the central area of the fore advantageously provided within a bacteria dressing after the dressing has been posi- proof pack such as a sealed aluminium foil or tioned on the patient. The added absorbent paper/plastic film pouch. Sterilization of the layer may be then maintained in contact with dressing can be carried out by a conventional the central area of the dressing by conven- 75 sterilizing method such as ethylene oxide, tional bandaging means. It is an advantage of electron or gamma irradiation.

this type of dressing of the present invention In use the wound dressing is removed from that when the handling areas have been used the pack and any protector present on the to adhere the wound contacting central area central area removed, then a protector cover to the skin then, if necessary, a soiled absor- 80 ing the adhesive coating on one handling area bent layer may be removed and replaced by a may be removed and the handling area ad fresh absorbent layer without disturbing the hered to the patient's skin thereby providing wound. Suitably the absorbent layer may be an anchor point for the dressing while the re formed from materials including gauze, cellu- mainder of the dressing is manoeuvred into lose pads, synthetic polymer foam and other 85 position. The protector on the other handling conventional body fluid absorbing materials. area may then be removed and the handling When an absorbent is present in the dressarea adhered to the skin.

ings of the invention it may be any of those In a second embodiment of the present in which are conventionally used in absorbent vention in which an absorbent means is pre dressings and may include. gauze or cellulose 90 sent in the wound dressing the handling areas pads or a synthetic polymer foam particularly may be attached to the absorbent material when formed from a hydrophilic polymer. A rather than to the polymer film.

preferred absorbent comprises a cotton/acrylic In a third embodiment of the present inven fibre fleece. Other absorbents include mixtures tion the central area may comprise a non-ad of cotton and viscose, acrylic fibres and the 95 herent wound dressing as described in Euro like. A second preferred absorbent comprises pean Patents Nos. 59048 and 59049 and a hydrophilic polyurethane foam, for example a which comprise an elastomeric net wound Hypol hydrophilic polyurethane foam as de- contact layer, an intermediate hydrophilic foam scribed in European Patents Nos. 59048, absorbent and optionally a moisture vapour 59049, 97517 and 106439 which are incor- 100 permeable film outer layer. Handling areas may porated herein by cross-reference. be attached to the wound dressings described

Suitably the absorbent layer will have a therein in the manner described hereinbefore.

width which is approximately equal to the cen- In a further aspect of the present invention tral area that is the distance between the provides a method of forming a wound dress- handling areas, however it is not disadvanta- 105 ing consisting essentially of a central area of a geous if the absorbent layer overlaps slightly non-wound adherent and adhesive free layer onto the handling areas. Of course if the cen- of polymer, an optional absorbent layer and tral area comprises an apertured film the abadhesive coated handling areas disposed out sorbent layer aptly covers at least the area wardly from the central area in which the ad which is apertured so as to avoid the risk of 110 hesive is covered by a removable protector unsightly leakage of body fluid. which method comprises forming the central The dressings of the present invention may area, attaching the handling areas to the cen be prepared by forming a film of the synthetic tral area covering the exposed pressure sensi polymer which is to form the central area, for tive adhesive areas on the handling areas with example by extrusion or by casting from a 115 a removable protector and when present at solution of the polymer. The film may then be taching the absorbent layer to the non-wound apertured, if required, by conventional means contacting face of the central area.

for example flame perforation, cutting slits, Optionally the central area may contain med embossing and fibrillation and the like. The icament. Suitable medicaments include broad adhesive coated handling area is then attached 120 spectrum antibacterial agents which may be to the central area as the appropriate posi- released to the surface to which the dressing tions, the remaining exposed adhesive surface is applied. Suitable antibacterial agents include of the handling area being covered by protec- silver sulphadiazine, chlorhexidine salts and tors. If present, the absorbent layer, pre cut salts of polymeric biguanides, known as Van to the appropriate width is laminated to the 125 tociis (Trade Marks). Favoured antibacterial central area between the handling areas by agents include salts of chlorhexidine such as conventional means, for example spot welding its d i hydrochloride, diacetate and digluconate.

or by the application of heat and pressure or Other suitable medicaments include antiflam by adhesive. The resulting strip of dressing matories, analgesica, local anaesthetics and material may be cut transversely to provide 130 antifungal agents such as the azole-type corn- GB2192792A 5 pounds. areas. Usually the handling areas will be iden Signified by miconazole, clotrimazole and tifiable by being pigmented.

metronidazole and combinations of antibacter- In use the release paper (1) is removed from ial agents such as azole-type compounds with covering the central area and then one of the silver compounds, for example silver sulphadi- 70 protectors (7) is removed. The adhesive on azine and metronidazole. the handling area so revealed may be used to Suitably the central area will contain an ef- adhere one edge of the dressing to the skin fective amount of the medicament and for to serve as an anchor point as the central example may contain upto 50% by weight of area of the dressing is placed over the the central area of antibacterial agent, more 75 wound. Then the remaining protector (8) is suitably from 5 to 35% by weight and prefer- removed and the other handling area is ad ably 10 to 25% by weight of antibacterial hered to the skin and the dressing is in place.

agent. Fig. 2 shows a cross-section through a Medicament may be present in the absor- dressing of the present invention comprising a bent layer and the adhesive layer of the hand- 80 perforated polyester film (11) having a series ling areas. Suitably the medicament may be of of perforations (12) across its width. Two op the same type as may be present in the cenposite edges of the polyester film are attached tral area and in the same proportions. to handling areas (13, 14) comprising adhesive In a final aspect the present invention pro- coated strips of a thermoplastic fibrillated net vides a method of treating a wound by re- 85 material. The strips of net are attached so moving a protector from a handling area of a that a major portion of the adhesive surface is dressing of the present invention and adhering not adhered to the polyester film but is in the handling area to the skin, placing the cen- stead covered by a siliconised release paper tral area of the dressing over the wound and protector (15, 16). An absorbent cotton/a removing the protectors from other handling 90 crylic fibre fleece (17) is positioned between areas before adhering said areas to the skin. the handles and is attached to the polyester Preferred embodiments of the present inven- film by spot welding.

tion will be described by way of example with In use one of the protectors (15) may be reference to the accompanying drawings in removed from the adhesive surface of the which 95 handling area and adhered to the skin. This Figure 1 represents a cross-section through may serve to anchor the dressing as the ab a dressing of the present invention in which sorbent portion is positioned over the wound.

the central area is covered by a protector The second protector may then be removed Figure 2 shows a cross-section through a and the handling area adhered to the skin. In dressing with adhesive coated handling areas 100 this way the dressing is conveniently adhered in which a portion of their adhesive surface is to the skin of the patient.

covered by protectors. Fig. 3 shows a cross-section through a Figure 3 shows a cross-section through a dressing of the present invention in which a dressing in which the protector is folded at protector (18) is adapted to cover the central one end and attached to a handling area. 105 area of the dressing and the exposed surface Figure 4 shows a cross-section through a of a handling area (24). The protector is dressing in which the protector is a split pro- folded near to one end so that the siliconised tector. surface contacts the exposed adhesive coating Figure 5 shows a cross-section through a of the handling area (24). A water swellable dressing in which one of the handling areas is 110 film (19) is laminated to a non-water swellable folded. film (20). The combination of the protector Fig. 1 shows a cross-section through a (18), and films (19, 20) are apertured by dressing of the present invention in which the means of slits (23) over the central area of release sheet (1) is a sheet onto which a the dressing. Protector (18) is adapted to water swellable film (2) is cast. A non-water 115 cover the exposed surface of a handling area swellable film (3) is laminated to the film (2) (24) along one edge of the dressing, the op usually by passing the two films and the re- posite edge of the dressing has a handling lease paper between a pair of heated rollers area (21) comprising an adhesive tape and a under pressure. Slits (4) are then placed removable protector (22). An absorbent ma- through the laminate and the release sheet. 120 terial (25) may be arranged between handling The handling areas are represented by adhe- areas (21) and (24).

sive coated films (5, 6). About one-third of In use the adhesive coating on the handling their width is used to adhere the handling area (21) is exposed by removing the protec areas to the non-water swellable film (3). The tor (22). The handling area (21) is then ad remainder of the adhesive surface of the hand- 125 hered to the skin. The protector (18) is then ling areas is covered by protectors (7, 8). An peeled back from the central area until the absorbent material (9) is arranged to have a central area is uncovered and the fold in the width so that it fits between the adhesive protector (18) is unfolded. The tension of un coated film (5, 6) but there may be some peeling this protector (18) causes the slits overlap of the absorbent onto the handling 130 (23) in the dressing to open slightly. The pro- 6 GB2192792A 6 tector (18) is then removed from handling area film material formed by the method described (24) and the handling area (24) adhered to the in British Patent No. 1531715 was applied to skin. two opposed edges of the perforated film to Fig. 4 shows a cross-section through a form handling areas. The adhesive surface ofdressing of the present invention in which the 70 the portion of each handling area not adhered protector (26) is in the form of a split protecto the perforated film as covered by a silicone tor the two halves of which overlap in the release paper.

central region of the dressing and completely An absorbent material comprising a cotto cover one surface of a water swellable film n/acrylic fleece was cut to the width of film (27). Each of the halves of the split protector 75 exposed between the handling areas and the (26) is folded near its edge so that the release fleece laminated to the perforated film using a surface contacts the exposed adhesive coating Reliant laminator at a temperature of 1000C of the handling areas (30) and (31). A water and pressure of 20 psi.

swellable film (27) is laminated to a non-water The dressing is cut to the appropriate length swellable film (28). The laminate contains slits 80 and packaged in a bacteria proof pack which (29). An absorbent material (32) may be ar- may be sealed and sterilised by gamma irradi ranged between the handling areas (30) and ation or ethylene oxide.

(31).

In use the split protector is peeled back to Example 2 expose the dressing. When the protectors are 85 A dressing is prepared in a similar manner fully extended the adhesive on the handling to that described in Example 1 except that the area is under shear so the protectors do not absorbent material used in a hydrophilic poly seperate from the adhesive surface. The urethane foam.

dressing may be placed over the wound and the parts of the protector removed by peeling 90 Example 3 from the adhesive coating on the handling A dressing is prepared in a similar manner area and the handling areas adhered to the to that described in Example 1 except that the skin. adhesive coated handles were attached to the Fig. 5 shows an alternative form of protec- absorbent material.

tor arrangement whereby instead of the pro- 95 tector being folded, the handling area (38) is Example 4 folded longitudinally around the edge of the A dressing is prepared by forming a lami laminate films (34, 35) and is attached to the nate comprising a silicone release paper, a hy surface of the protector (33) which is not in drophilic polyurethane and a styrene-butadiene- contact with the laminate films (34, 35). The 100 styrene-tri block copolymer employing a similar opposed edge of the laminate film carries a method to that described in Example 1 of handling area (36) whose exposed adhesive European Patent Application No. 122085.

surface is covered by a protector (37). in use The films on the release paper were then the protector (37) is removed and the handling perforated by slits 3mm in length spaced area (36) adhered to the skin. The protector 105 2mm apart and with 7mm spacing between (33) is peeled away from the surface of the lines of adjacent slits.

film (34) until the surface is completely unco- An adhesive coated fibrillated thermoplastic vered. The protector (33) being attached to net material formed by the method described film (35) by the handling means (38) can be in British Patent No. 1531715 is applied to used to apply the bandage under tension so 110 two opposed edges of the perforated film to that slits (39) are slightly opened. The protec- form handling areas. The adhesive surface of tor (33) may be peeled from handling area the portion of each handling area not adhered 1 (38) and the area adhered to the skin. An to the perforated film is covered by a silicone absorbent pad may be placed in contact with release paper.

the film (35) if necessary. It is preferred in the 115 The dressing is then cut to the appropriate embodiment that the protector (33) is covered length and packaged in a bacteria proof pack on both major surfaces by a release coating. which is sealed and sterilised by gamma irradi ation or by ethylene oxide.

Example 1 In use the dressing is removed from the A laminate comprising a silicone release pa- 120 bacteria proof pack. The silicone release paper per, a hydrophilic polyurethane and a styrene- is removed from the apertured central area. A butadiene-styrene tri-block copolymer was preprotector is then removed from a handling pared in a similar manner to that described in area which is adhered to the skin. The remain Example 1 of European Patent Application No. der of the dressing is arranged over the 122085. 125 wound and the second protector removed and The films and release paper were then per- the second handling area adhered to the skin.

forated by slits 2mm in length spaced 2mm A separate absorbent layer may then be apart with 5mm spacing between lines of ad- placed over the central area and held in place jacent slits. by a conventional bandage for example p lin- An adhesive coated fibrillated thermoplastic 130 ear or tubular elastic bandage.

7 GB2192792A 7 sure sensitive adhesive area covered by a re- Example 5 movable protector.

A flame-perforated polyester film is slit to a 2. A wound dressing as claimed in claim 1 width of 8.5cm. An adhesive-coated tape in which the handling areas are provided at formed from a fibrillated thermoplastic net 70 two opposite edges of the central area.

comprising a blend of polyethylene and poly- 3. A wound dressing as claimed in either styrene coated with an acrylic ester copolymer of claims 1 or 2 in which the handling area is pressure sensitive adhesive and 2.5cm wide is net formed by the fibrillation of thermoplastic applied to two opposite edges of the poly- embossed polyolefin film.

ester film so that approximately 0.5mm of the 75 4. A wound dressing as claimed in any strip is adhered to the edge of the polyester one of claims 1 to 3 in which the adhesive film. The remainder of the adhesive coated coated handling area has a moisture vapour surface of the tape is covered by a release transmission rate of at least 25OgM-2 24hr-1 paper. A strip of cotton/acrylic fibre fleece, at 37'C and 100% to 10% relative humidity 7,5cm wide, is placed between the handles 80 difference.

and spot welded to the exposed polyester 5. A wound dressing as claimed in any film surface. Dressings of the required size are one of claims 1 to 4 in which all of each formed by cutting transversely across the strip handling area is coated with a pressure sensi so formed. tive adhesive.

The dressings are packaged in a bacteria 85 6. A wound dressing as claimed in any proof pack and sterilised by ethylene oxide or one of claims 1 to 5 in which the central area gamma irradiation. is an apertured film.

In use the sterile dressings may be removed 7. A wound dressing as claimed in claim 6 from the pack and the protector paper re- in which the central area is a conformable film moved from one of the adhesive coated 90 with apertures in the form of slits there handles. The handle may then adher to the through said conformable film comprising a skin while the remainder of the dressing is first layer for contacting the wound laminated positioned over the wound. The second pro- to a second layer, said first layer comprising a tector may then be removed and the second material which when in contact with water handle adhered to the skin. 95 swells and said second layer comprising a ma terial which when in contact with water does Example 6 not swell or swells less than the first layer.

A dressing is prepared by taking a net 8. A wound dressing as claimed in claim 7 formed in the manner described in Example 2 in which the first layer is a hydrophilic poly- of British Patent No. 1548865 and applying to 100 urethane and the second layer is styrene-buta two opposed edges of the net an adhesive diene triblock copolymer.

coated fibrillated thermoplastic net material 9. A wound dressing as claimed in claim 6 formed by the method described in British Pa- in which the apertured film is a perforated tent No. 1531715. The adhesive surface of polyester film.

the portion of each handling area not adhered 105 10. A wound dressing as claimed in claim to the net is covered by a silicone coated 6 in which the apertured film is a net.

release paper. 11. A wound dressing as claimed in claim The dressing may be packaged in a bacteria 6 in which the central area is an open knit proof pack and sterilised as described herein rayon fabric.

before. 110 12. A wound dressing as claimed in claim 1 in which the central area is a continuous, Example 7 moisture vapour permeable film, which film A dressing is prepared by taking an open has a moisture vapour transmission rate of knit rayon fabric and applying to two opposed greater than 250 9M-2 24 hr- 1 at 37C and edges of the fabric an adhesive coated fibril- 115 100% to 10% relative humidity difference.

lated thermoplastic net material formed by the 13. A wound dressing as claimed in claim method described in British Patent No. 12 in which the film comprises a hydrophilic 1531715. The adhesive surface of the portion polyurethane which contains from 20 to 40% of each handling area not adhered to the fab- by weight of water when hydrated.

ric is covered by a silicone coated release pa:- 120 14. A wound dressing as claimed in any per. one of claims 1 to 13 in which an absorbent layer is additionally present at the non-wound

Claims (1)

1. CLAIMS facing side of the central area.

   1. A wound dressing which consists 15. A wound dressing as claimed in claim essentially of a central area and at least one 125 14 in which the absorbent layer is a cotton/a handling area outwardly disposed from said crylic fibre fleece.

   central area, which central area is adhesive 16. A wound dressing as claimed in claim free and is non-adherent to wounds and which 14 in which the absorbent layer is a hydro comprises a layer of polymer and in which at philic polyurethane foam.

   least one of said handling areas has a pres- 130 17.A wound dressing as claimed in any 8 GB2192792A 8 one of claims 1 to 16 in which the pressure sensitive adhesive is an acrylate ester copolymer adhesive and is present at a weight per unit area of 10 to 75gm-2.

   18. A wound dressing as claimed in any one of claims 1 to 17 in which the central area contains a medicament.

   19. A wound dressing as claimed in claim 18 in which the medicament is antibacterial and comprises from 1 to 25% by weight of the central area.

   20. A wound dressing as claimed in any one of claims 1 to 19 which is sterile and is packaged in a bacteria-proof pack.

   Published 1988 at The PatentOffice, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.