DRESSING WITH IMPROVED FLUID DISTRIBUTION

Abstract

A dressing including a film which is impermeable to fluids and permeable to water vapor, and the entire surface of which is covered by a perforated reinforcement coated with a medically acceptable adhesive which is the same or different on each of the faces thereof, the face opposite to the face in contact with the impermeable film of an adhesive being partially covered by an absorbent pad, The dressing further includes a layer for distributing the fluids which is positioned between the impermeable film and the perforated reinforcement.

Claims

1-17. (canceled)

18. A dressing, comprising: a film which is impermeable to fluids and permeable to water vapour, and the entire surface of which is covered by, a perforated reinforcement coated with a medically acceptable adhesive which is the same or different on each of the faces thereof, the face opposite to the face in contact with said impermeable film being partially covered by, an absorbent pad, wherein said dressing further comprises a fluid distribution layer inserted between said impermeable film and said perforated reinforcement.

19. The dressing according to claim 18, wherein said film which is impermeable to fluids and to water vapour is made of polyurethane.

20. The dressing according to claim 18, wherein said perforated reinforcement is coated on the face thereof in contact with said impermeable film with a medically acceptable adhesive and on the other face thereof with an adhesive silicone gel.

21. The dressing according to claim 18, wherein said film which is impermeable to fluids and to water vapour has a thickness between 5 μm and 100 μm.

22. The dressing according to claim 18, wherein said film which is impermeable to fluids and to water vapour has an MVTR breathability to water vapour in liquid contact, measured after 4 hours of tests as per the EN 13726-2:2002 standard, between 500 g/m.sup.2/24h and 60,000 g/m.sup.2/24h.

23. The dressing according to claim 18, wherein said fluid distribution layer extends over a surface less than that of the absorbent pad.

24. The dressing according to claim 18, wherein said fluid distribution layer extends over the entire surface of the absorbent pad.

25. The dressing according to claim 18, wherein said fluid distribution layer extends over the entire surface of said absorbent pad and beyond the surface of the absorbent pad.

26. The dressing according to claim 18, wherein said fluid distribution layer is composed of a woven or knit textile, a nonwoven material, or an absorbent material.

27. The dressing according to claim 18, wherein said woven or knit textile is composed of natural fibres or of synthetic fibres.

28. The dressing according to claim 26 wherein said nonwoven textile is composed of a material chosen in the group consisting of polyethylene, polypropylene, polyester or polyamide and mixtures thereof.

29. The dressing according to claim 26 wherein said absorbent material is composed of a material chosen in the group consisting of hydrophilic polyurethane, carboxymethylcellulose fibres, sodium polyacrylate, sodium alginate, carboxymethylcellulose, sodium polyacrylate, sodium alginate, and mixtures thereof.

30. The dressing according to claim 18, wherein said perforated reinforcement is a perforated knit, a unitary net made of thermoplastic material, a perforated film or a perforated nonwoven.

31. The dressing according to claim 18, wherein said adhesive is a hydrogel, a pressure-sensitive adhesive (PSA) or a silicone-based adhesive.

32. The dressing according to claim 18, wherein the total weight of adhesive on all of both faces of the perforated reinforcement is between 30 g/m.sup.2 and 500 g/m.sup.2.

33. The dressing according to claim 18, wherein the perforated reinforcement has an opening rate between 5% and 50%.

34. The dressing according to claim 18, wherein the absorbent pad consists of a material chosen in the group consisting of hydrophilic polyurethane foams, absorbent nonwoven materials based on carboxymethylcellulose fibres or sodium alginate, composites based on porous nonwoven materials comprising sandwiched absorbent materials and sachets containing absorbent materials.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0041] FIG. 1 shows a sectional view of an embodiment of a dressing according to the invention.

[0042] FIG. 2 shows the progression of the breathability of an embodiment of a dressing according to the invention as a function of the surface area of the distribution layer.

[0043] FIG. 3 shows the progression of the breathability of an embodiment of a dressing according to the invention as a function of the opening rate of the perforated reinforcement.

DETAILED DESCRIPTION

[0044] The preferred embodiment of the dressing according to the invention described in FIG. 1 comprises: [0045] a film 1 which is impermeable to fluids and permeable to water vapour, and the entire surface of which is covered by, [0046] a perforated reinforcement 3 coated on the face thereof in contact with said impermeable film with an adhesive and on the other face thereof with an adhesive silicone gel, the latter face being partially covered by, [0047] an absorbent pad 4, [0048] a fluid distribution layer 2 inserted between said impermeable film 1 and said perforated reinforcement 3.

[0049] The surface area of said dressing, the shape thereof, the surface area of the border and of the absorbent pad 4 are dependent on the type of wounds to be treated. A person skilled in the art is capable of defining, for each need, the optimum surface areas of each of the components.

[0050] The surface area of the border can be increased to improve the ability of the dressing according to the invention to adhere to the patient's skin.

[0051] The adhesiveness of the perforated reinforcement 3 can also be modified by varying: [0052] the dimension of the holes (length, width or diameter) which can vary between 0.1 mm and 8 mm, preferably between 1.0 mm and 3 mm, [0053] the distribution thereof in relation to each other (e.g. positioning at 45°, at 60° or at 90°), [0054] the density thereof in number per unit of surface area, defined by an opening rate represented by the ratio between the open surface area relative to the total surface area.

[0055] Usually, the surface area of the distribution layer 2 is equivalent to that of the absorbent pad 4 placed next to the latter. However, said distribution layer 2 can advantageously extend beyond said absorbent pad 4 in order to improve the breathability of the dressing at the border and discharge the moisture released by sudation at the border.

[0056] Said distribution layer 2 can also have a surface area less than that of the pad 4 so as to obtain a breathability that is certainly sufficient, but not excessive so as not to risk drying the bed of the wound.

[0057] The different layers of the dressing according to the invention can be produced and assembled by any means known to a person skilled in the art.

[0058] Preferably, the film which is impermeable to fluids and permeable to water vapour 1 can be obtained by blown film extrusion, by flat extrusion, by solvent-phase liquid coating on a substrate based on paper or synthetic film both coated with an anti-adherent layer.

[0059] Preferably, the perforated reinforcement 3 coated on both faces thereof with one or more medically acceptable adhesives can be obtained by coating both faces, for example by coating or steeping in a bath, of a perforated knit type open textile or a unitary net made of thermoplastic material, or perforating a film of a nonwoven previously coated on both faces thereof with one of more medically acceptable adhesives. The open knit can be obtained by so-called “warp” knitting. The unitary material net can be obtained by extrusion casting followed by hot stretching after perforation. The film can be obtained by blown film extrusion, by flat extrusion, or by liquid coating in solvent phase on a carrier. The nonwoven can be obtained by so-called melt blown or spunbound technology if the selected fibres are thermoplastic or by so-called spunlace technology in the case of nonwoven materials containing non-thermoplastic fibres.

[0060] All the materials cited in the present application can be advantageously combined with functional agent for treating the wound such as antimicrobial, disinfectant, and-odour, wound treatment activating and/or detergent products.

[0061] A corona treatment as described by the applicant in the document WO2015044535 A1 can be advantageously applied to the silicone adhesive on the surface intended to be bonded thereto (pad 4 and/or breathable impermeable film 1)

Examples

Example 1: Demonstration of the specific effect of a distribution layer 2 on breathability

[0062] In order to demonstrate the effect of the distribution layer 2 on the breathability of a construction according to the invention, the applicant constructed assemblies comprising [0063] a film which is impermeable to fluids and permeable to water vapour 1, and the entire surface of which is covered by, [0064] a perforated reinforcement 3 coated on the face thereof in contact with said impermeable film, [0065] a fluid distribution layer 2 inserted between said impermeable film and said perforated reinforcement (except for control sample).

[0066] The perforated reinforcement 3 was a polyurethane film, coated on one face with acrylic adhesive and on the other face with silicone adhesive, then perforated and assembled with polyurethane films 1 with and without (control) insertion of a distribution layer 2.

[0067] In the assembly obtained, assembled disks of overall diameter 42 mm were cut, optionally comprising a diffusion disk, bonded at the centre thereof, of diameter arbitrarily defined as 24 mm, then subjected to the breathability measurement test in liquid contact (MVTR) as per the EN 13726-2:2002 period for a 4h duration.

[0068] The perforated reinforcement 3 was manufactured by the applicant under the reference Acrysil 150 703731, perforated with holes at 60°, diameter 2.4 mm and 15% opening rate.

[0069] The distribution layers 2 evaluated are: [0070] a 45 g/m.sup.2 polyester nonwoven (reference Sontara Spunlace Style 8000 distributed by Jacob Holm Industries). [0071] a polyurethane foam of thickness 1.5 mm (reference Vilmed 6217 manufactured by Freudenberg). [0072] an absorbent nonwoven (reference Vilmed M1556 manufactured by Freudenberg).

[0073] The films which are impermeable to fluids and permeable to water vapour 1 used were: [0074] A film of thickness 15 μm (reference Inspire 2350, manufactured by Transcontinental Advanced Coating Ltd). [0075] A film of thickness 30 μm (reference Inspire 2301, manufactured by Transcontinental Advanced Coating Ltd).

[0076] The MVTR breathability observed for each of these constructions is stated in [Table 1] below.

TABLE-US-00001 TABLE 1 Control Assembly Assembly Assembly assembly with with with (with no diffusion polyester polyurethane absorbent layer) nonwoven foam nonwoven PU film 5442 14224 14058 20839 15 μm g/m.sup.2/24 h g/m.sup.2/24 h g/m.sup.2/24 h g/m.sup.2/24 h PU film 2945 7664 9443 11448 30 μm g/m.sup.2/24 h g/m.sup.2/24 h g/m.sup.2/24 h g/m.sup.2/24 h

[0077] It is thus observed, surprisingly, that inserting a diffusion layer 2 between the perforated reinforcement 3 and the film 1, makes it possible to increase, by 160% to 290% depending on the cases, the breathability of the complex.

[0078] Even more surprisingly, the breathability increases very substantially if the distribution layer 2 tends to swell on absorbing the liquid (case of Vilmed 6217 foam), then inducing a deformation elongation of the film 1 since it is not bonded; this then results in greater breathability of the film 1 by elongation, increase in the exchange surface area, and reduction in thickness.

Example 2: Demonstration of the effect of a distribution layer 2 on the breathability of a dressing according to the invention

[0079] The assemblies of example 1 are produced identically on the 15μm film 1, but an absorbent polyurethane foam disk is bonded to the perforated reinforcement 3, on the silicone adhesive side, to represent the absorbent pad 4.

[0080] The absorbent polyurethane foam pad 4 used has a thickness of 2 mm (reference MC F03 manufactured by Advanced Medical Solutions Group Plc).

[0081] The assembled disks, of diameter 42 mm, optionally comprising a distribution layer 2 of diameter 24 mm, are subjected to the breathability measurement test in liquid contact (MVTR) as per the EN 13726-2:2002 period for a 4h duration.

[0082] The MVTR breathability observed for each of these constructions is stated in [Table 2] below.

TABLE-US-00002 TABLE 2 Control Assembly Assembly Assembly assembly with with with (with no diffusion polyester polyurethane absorbent layer) nonwoven foam nonwoven PU film 5414 13767.6 11964 17136 15 μm g/m.sup.2/24 h g/m.sup.2/24 h g/m.sup.2/24 h g/m.sup.2/24 h

[0083] It is thus observed that adding an absorbent pad 4 reduces the overall MVTR of the dressing slightly, but the effect due to inserting the distribution layer 2 is not cancelled.

Example 3: Effect of the variation of the surface area of the distribution layer 2 on the breathability of a dressing according to the invention

[0084] Assemblies according to example 1 with a 15μm film 1 were produced by varying the diameter, therefore the surface area of the distribution layer 2.

[0085] The distribution layer 2 evaluated was a 45 g/m.sup.2 polyester nonwoven (reference Sontara Spunlace Style 8000 distributed by Jacob Holm Industries).

[0086] The assembled disks, of diameter 42 mm, optionally comprising a distribution layer 2 of variable diameter (12, 18, 24 & 30 mm) were subjected to the breathability measurement test in liquid contact (MVTR) as per the EN 13726-2:2002 period for a 4h duration.

[0087] The results obtained are shown in [FIG. 2].

[0088] It is thus observed that the distribution layer 2 fully fulfils its role, the moisture being evaporated over a greater surface area of film 1.

[0089] Consequently, it is possible to vary the MVTR breathability by merely varying the surface area of the distribution layer 2. In some cases, it may be desirable to have a maximum breathability to prevent an accumulation of exudates at the wound and thus tissue maceration. On the other hand, in some cases, it is necessary to limit the breathability of the dressing to prevent drying of the wound bed and thus promote wound healing.

Example 4: Effect of the variation of the opening rate of the perforated reinforcement 3 on the breathability of

[0090] a dressing according to the invention.

[0091] Assemblies according to example 1, comprising a 15 μm film 1, were constructed by varying the perforation design of the perforated reinforcement 3 so as to generate perforations having different diameters and opening rates.

[0092] Assemblies, of diameter 42 mm, optionally comprising a distribution disk 3 of diameter 24 mm, are subjected to the breathability measurement test in liquid contact (MVTR) as per the EN 13726-2:2002 period for a 4h duration.

[0093] The results obtained are shown in [FIG. 3].

[0094] It is observed that, without a distribution layer 2, the breathability remains closely dependent on the opening rate of the perforated reinforcement 3. Conversely, in the presence of the distribution layer 2, the MVTR is virtually stable according to the opening rate and therefore the adhesive power of the dressing according to the invention.

[0095] Consequently, unlike the dressing according to the prior art, the dressing according to the invention makes it possible to readily modify the breathability of the dressing without modifying the opening rate of the perforated product and therefore without modifying the adhesive power thereof on the patient. Conversely, it is possible to modulate the adhesive power of the dressing on the skin and/or the absorbent pad 4 on the perforated reinforcement 3 (by modifying the opening rate of the perforated reinforcement 3 and/or the size of the borders) without modifying the overall breathability of the finished dressing.

[0096] Additionally, it is thus possible to modulate and optimise the two features of breathability and adhesive power completely independently unlike the dressings of the prior art.