Pressure-stable wound treatment product which can be cut to size for necrotic ulcers

Abstract

The invention relates to a wound treatment product which can be cut to size and which comprises a liquid-permeable layer with a nonwoven material, a protective layer with a nonwoven material, and a swelling layer. The swelling layer contains an aqueous salt solution and superabsorbent fibers, said superabsorbent fibers being provided in a textile composite comprising at least one type of support fiber. The wound treatment product can optionally have a backing on the upper face and a silicone-containing atraumatic wound contact layer on the lower face. The wound treatment product makes do without seams and is characterized by its excellent pressure stability.

Description

[0001] Pressure-resistant, cuttable wound care product for necrotic ulcers

[0002] Technical field of the invention

[0003] The invention relates to a textile, multi-layer wound care product suitable for the treatment of various wounds, in particular ulcers, and especially ulcers on the sole of the foot. Due to its special structure, the wound care product is capable of performing physical-autolytic debridement, thereby gently removing necrotic tissue from the wound and thus initiating wound closure.

[0004] Background of the invention

[0005] Wound dressings for moist wound care are generally known from the state of the art.

[0006] One variant is described in WO 2011 / 141454 A1. It is a wound pad-like or compress-like wound dressing that can be applied to a wound or used to pack deep wounds. This product comprises an absorbent / irrigating body with a circumferential welded seam and is coated with a saline aqueous solution by the manufacturer, causing the superabsorbent material it contains to swell and transform into a gel-like state. This gives the absorbent / irrigating body a dual function for wounds with heavy exudation: Wound secretions, including the components they contain, such as germs, are actively absorbed and retained by the absorbent / irrigating body. In exchange, the absorbent / irrigating body releases the saline aqueous solution into the wound, thus creating or supporting a moist wound environment.This supports wound cleansing and positive wound conditioning, thus positively influencing healing. This is referred to as interactive wet therapy, which is particularly preferred for poorly healing wounds, clinically manifestly infected wounds, or chronic wounds of various etiologies, such as diabetic gangrene, decubitus ulcers, or leg ulcers. However, wound dressings of this type have the disadvantage that they are not designed to be adjusted to the size of the wound (after production), e.g., cut to size. The reason for this is that when cutting, the outer barrier, including the welded seam, is severed and the gel then oozes out. Cutting while dry and then adding liquid later is also not possible, because after cutting, the superabsorbent particles fall out from the interior and, in the worst case, remain in the wound.Even without cutting the product, the welded seam can tear under extreme pressure, causing the gel or superabsorbent polymer (SAP) particles to leak out. Therefore, such a state-of-the-art product is not suitable for the treatment of llcera on the sole of the foot, which often occurs in diabetics, or can only be used if the patient avoids it, for example, by lying down or elevating the affected leg. Otherwise, the wound dressing risks bursting as soon as the patient shifts their weight onto the foot being treated. Treatment while lying down or using crutches is stressful for the patient. Prolonged lying down increases the risk of thrombosis, and crutches are particularly stressful for older patients.

[0007] The information presented with reference to WO 2011 / 141454 A1 applies almost identically to the wound dressing disclosed in WO 2016 / 156619 A1. This is also intended for moist wound care and is provided in the form of a sheet material consisting of several layers that are only connected at the edges by a welded seam. Otherwise, the layers can shift against each other, for example, during body movements, creating a flexible arrangement. This wound dressing cannot be cut to size and is not suitable for use on the sole of the foot.

[0008] While the above-mentioned products can be used to treat ulcers, such as those found on leg ulcers, a problem often arises: Since the products cannot be tailored to the size of the wound, they inevitably extend beyond the wound. Because they are applied in a moist form, the healthy skin surrounding the wound will swell over time. This undesirable effect is known as maceration and, in the worst case, can lead to wound enlargement.

[0009] Consequently, there is a need for a wound dressing suitable for the treatment of various wounds, especially ulcers, including those on the sole of the foot. It can be tailored to the size of the wound, removes necrosis, and creates a moist wound environment, thus promoting wound closure without restricting the patient's mobility during treatment. Furthermore, maceration of the wound edges should be avoided.

[0010] Summary of the invention

[0011] The above object is achieved by providing a wound care product comprising the following components: a) a proximal liquid-permeable layer comprising a nonwoven fabric, b) a distal protective layer comprising a nonwoven fabric, c) a swelling layer in the form of a nonwoven fabric with superabsorbent, polymer-containing fibers located between the proximal liquid-permeable layer and the distal protective layer, wherein the superabsorbent fibers are present in a felt with at least one other fiber type, d) an aqueous salt solution which is embedded in the swelling layer, has a pH < 7.0 in the embedded state and can be released into a wound during wound treatment, wherein the proximal liquid-permeable layer, the swelling layer and the distal protective layer have an identical cut and lie against one another over their entire surface without any overhang,and wherein the wound care product is designed to be seamless.,

[0012] Alternatively, the wound care product may consist of the above-mentioned components.

[0013] Due to the described design, the wound dressing according to the invention can be tailored to the size of the wound and, if application to the sole of the foot is planned, the patient remains mobile during treatment. Furthermore, any possible protrusion of the wound dressing beyond the sole of the foot is prevented, so that, for example, wearing shoes is still possible. When body weight is shifted onto the wound dressing, the wound is rinsed more intensively via the saline solution and when the load is subsequently removed (weight on the other leg), most of the solution is reabsorbed by the wound dressing. This results in repetitive physical autolytic debridement, which can remove cellular debris, pus and, above all, necrotic deposits. At the same time - in the event of a wound infection - pathogens are flushed from the wound and absorbed by the wound dressing, where they are retained.Together with the moist wound environment, optimal conditions are created to stimulate healing, especially of chronic wounds, and to improve the quality of life of the affected patients.

[0014] Detailed description of the invention

[0015] The term "cuttable" means that a product or material can be specifically reduced to a size intended by the user before use using a commercially available mechanical tool such as scissors, without the product or material losing its functionality and without undesirable (partial or complete) degradation of the product or material. The term "medically acceptable material" as used herein is a non-toxic, lint-free, and stable substance that does not decompose into polar or non-polar substances under normal conditions and cannot be significantly degraded by the secretions of animal or bacterial cells.

[0016] The term “atraumatic” means that a wound care product does not bond firmly to the wound, i.e. it does not dry out or grow into the wound, and that the product can be removed painlessly without disrupting the healing process.

[0017] The term “configured for application to a wound” means that the wound care product is intended to be applied to a wound for a therapeutic purpose in the sense of wound treatment.

[0018] "Ringer's solution" is an aqueous solution containing sodium chloride, potassium chloride, and calcium chloride (specifically 8.6 g NaCl, 0.3 g KCl, and 0.33 g CaCl per liter of water), which is essentially isotonic (osmolarity of approximately 308 mOsm / L). Ringer's solution is usually sterilized before use.

[0019] "Proximal," in the context of the present invention, means that a material or substance occupies a position within a wound care product such that it is positioned toward the wound during wound care application. This is the case, for example, with a wound contact layer.

[0020] “Distal” in the context of the present invention means that a material or substance occupies a position within a wound care product such that it is arranged away from the wound within this product during use in wound care, as is the case, for example, with a backing (final support layer).

[0021] "SAF" is an abbreviation for superabsorbent fibers. These fibers are capable of absorbing many times their own weight in polar liquids and can be combined with other fibers to form a stable fiber composite.

[0022] "Additive fiber" refers to a fiber that is different from superabsorbent fibers (SAF) and is therefore not a SAF itself. "Moisture Vapor Transmission Rate" or "MVTR" refers to a measurement that expresses the permeability of water vapor through a specific material in g / m 2 / 24h. The MVTR can be determined using the standard DIN EN 13726-2 (June 2002).

[0023] The wound care product according to the invention consists of at least three layers: a proximal fluid-permeable layer, a swelling layer, and a distal protective layer. All three of these layers have an identical cut, so that they lie flush against each other without any overlap. However, minor production-related deviations (tolerances) are possible without compromising function. One or two layers can protrude up to 5 mm beyond another layer(s).

[0024] The proximal fluid-permeable layer can function as a wound contact layer. Alternatively, the wound care product can be equipped with an additional silicone-containing layer, which then assumes the role of the wound contact layer and offers excellent atraumatic properties. The corresponding procedure is explained in detail elsewhere.

[0025] The distal protective layer covers the swelling layer distally, protecting it from external influences and facilitating handling of the wound care product by improving its haptic properties. The effectiveness of the protective layer can be further enhanced by the additional application of a backing, which is explained in detail elsewhere.

[0026] The pressure resistance is achieved through the product's construction, with the composition of the swelling layer, comprising a felt made of SAF and additional fibers, and the resulting elimination of a welded seam being crucial. Seamless means, in particular, that the product has no welded seam. In this way, the required pressure resistance values ​​can be achieved. Accordingly, the wound care product reacts to mechanical pressure only through elastic and thus reversible deformation. Thus, it can preferably be provided that the wound care product has a pressure resistance of at least 8 kg / 100 cm 2 , preferably 20 kg / 100 cm 2 , even better at least 50 kg / 100 cm 2 and preferably 120 kg / 100 cm 2The pressure resistance value is defined as a force distributed across the entire (distal or proximal) surface of the wound care product (full-surface pressure resistance). Pressure resistance can be tested using the following procedure:

[0027] 1) Provide a wound care product treated with aqueous saline solution that has been sterilized within the last 14 days.

[0028] 2) Place the (unpacked) product in a standard, transparent zip bag

[0029] 3) Build-up of the weight force to be tested within one second

[0030] 4) Hold the weight force for one second

[0031] 5) Reduction of weight force within two seconds

[0032] 6) Repeat steps 3 to 5 so that the weight force is applied a total of ten times

[0033] 7) Removing the product from the bag

[0034] 8) Visual inspection of both the product and the inside of the bag for separated fibers or leaked gel

[0035] If no separated fibers or leaked gel are visible on the product itself or inside the bag, the test is considered passed for the corresponding weight force.

[0036] Preferably, the wound care product is designed in such a way that, due to its elastic properties and compressive strength, it can be turned or folded by 90°, even better by 180° along an actual or (in the case of an asymmetrical structure) imaginary center line, without any plastic deformation taking place.

[0037] The proximal fluid-permeable layer and the protective layer may comprise other components in addition to the aforementioned nonwoven fabric, such as other fiber arrangements, as long as they do not disintegrate after a cutting process. Preferably, the fluid-permeable layer and the protective layer are made entirely of nonwoven fabric, as nonwoven fabrics are particularly resistant to fraying, even after cutting.

[0038] The swelling layer contains superabsorbent fibers (SAF), in particular superabsorbent fibers which contain a superabsorbent polymer. The superabsorbent polymer preferably comprises an acrylate-containing polymer or an acrylate copolymer. The SAF can have a fiber diameter of, for example, 50 to 500 pm. A fiber diameter of 100 to 200 pm is preferred, as an ideal water-to-fiber ratio can develop at this diameter. This allows a larger amount, for example 15 ml, of an aqueous saline solution to be released from the swelling layer into the wound, but can also be reabsorbed. This mechanism is based on chemical-physical processes such as diffusion, in which clean saline solution migrates towards the wound and rinsed out wound exudate migrates towards the swelling layer.Second, the saline solution is partially extruded under mechanical pressure and reabsorbed by the swelling layer when the pressure is released. Options for providing and adapting SAF are discussed in more detail elsewhere.

[0039] The wound care product is preferably flat, i.e., it has a flat distal upper surface and a similarly flat proximal underside, making it ideal for wound coverage and sitting flush with the wound edges. Flat means that the respective layer has no significant elevations or depressions. The aforementioned protective layer can serve as the upper surface. The aforementioned proximal, fluid-permeable layer can serve as the underside. This allows the product to be easily draped over the wound. The flat underside supports the atraumatic properties and reduces wound irritation.

[0040] The wound care product is also preferably round or elliptical (when viewed from above). Compared to rectangular shapes, this has the advantage that, even in its uncut state, the product resembles the shape of most chronic wounds, which (unlike, for example, cuts) usually have a circular appearance. Furthermore, it has been shown that round or elliptical shapes can be better and more permanently fixed to the sole of the foot and are less uncomfortable for the wearer than other shapes, such as rectangular shapes with rounded corners, which are often used for abrasions. Furthermore, rectangular shapes have the disadvantage that, under continuous mechanical stress—such as when walking—they quickly begin to detach from the skin around the corners. The corners tend to curl up, which leads to an unwanted elevation and can cause pressure pain in the sole of the foot.

[0041] When applied to a wound or to cover a wound, the protective layer is preferably overlaid distally with an additional backing layer, which counteracts the evaporation of the saline solution, allowing moist wound treatment to take place continuously over a period of several days without dressing changes. The backing layer or backing also provides supporting properties that simplify the wrinkle-free application or adhesion of the wound care product. The advantage here is that the SAF in the swelling layer has excellent water retention properties. The felt material of the swelling layer can also absorb and retain substances and harmful organisms (e.g., bacteria) washed out of the wound until they are disposed of at the next dressing change.

[0042] The wound care product according to the invention contains a swelling layer in the form of a nonwoven fabric with superabsorbent, polymer-containing fibers. The superabsorbent fibers are combined with at least one other fiber type (additional fiber) in a felt fiber composite. The purpose of these additional fibers is to provide the swelling layer with sufficient tear and tensile strength, as well as dimensional stability in a wet state. Since the SAF and the additional fiber are combined in a felt, they form a stable fiber composite.

[0043] With regard to the swelling layer, the additional fiber ("other fiber") can be a fiber type of synthetic, natural, or semi-synthetic origin, with SAF explicitly excluded. Examples of suitable fibers of synthetic origin are polyolefin-based fibers such as polyester and polyamide. Within the group of polyesters, polyethylene terephthalate is particularly suitable. Examples of suitable fibers of natural origin include cotton and flax. An example of a fiber of semi-synthetic origin is lyocell. Natural and semi-synthetic fibers together form the group of cellulosic fibers, provided they contain cellulose components.

[0044] The additional fiber is present together with the SAF in a felt, preferably a needle felt. This means that the two fiber types are felted together. The felt can be produced as a wet felt or as a dry felt. Production as a dry felt is preferred, as this prevents re-drying of the SAF. The dry felt can be provided as a needle felt, adhesive felt, or thermally bonded melt felt. In a needle felt, the additional fibers and the SAF are mechanically needled together to form a felt. The other fiber type (additional fiber) can be needled with the superabsorbent, polymer-containing fibers in such a way that it forms a needle felt. In an adhesive felt, the two fiber types are bonded together by adding an adhesive (mainly through chemical interaction).The adhesive used should not be water-soluble after curing, as otherwise it could degrade due to the action of the aqueous salt solution. In a melt-felt, the additional fiber is selected from the melt-felt range and bonded to the SAF (which possess inherent melt-felt properties) using thermal energy. Preferably, the fibers of the swelling layer are in the form of needle felt or needle felt. A swelling layer in the form of needle felt offers the advantage of being compatible with all sterilization methods, as it demonstrates excellent resistance to heat, pressure, steam, radiation, and ethylene oxide. Furthermore, the needle felt form allows for considerable flexibility in the selection of fibers and boasts a very long shelf life, even after extended storage.

[0045] The swelling layer constructed in this way can be easily cut without the SAF and the additional fiber separating from each other, and without superabsorbent particles, such as those frequently used in absorbent wound dressings, falling out of the swelling layer in the cut area. Furthermore, permanent attachment to the other layers of the wound care product is possible. For example, it is possible to bond the swelling layer to other materials on its distal and proximal sides. Examples of how such laminates can be obtained are described in the exemplary embodiments.

[0046] The wound care product according to the invention is excellently suited for moist wound treatment. "Suitable for moist wound treatment" or "for moist wound treatment" means that the product can be used without further preparation or modification, so that moist wound treatment begins immediately upon application. This allows the wound care product to be stored in a moist state between production and use without compromising its structural integrity.

[0047] The saline solution contained in the swelling layer irrigates the wound, dissolving deposits such as fibrin, supporting the autocatalytic degradation of necrotic tissue, and removing microorganisms. Excess matrix metalloproteinases are flushed from the wound, and stagnant healing processes are restarted. The moist environment also generally accelerates wound closure.

[0048] If the product is attached to the sole of the foot, the movement stimulates venous blood flow, which is particularly important for chronic wounds caused by venous congestion (e.g., leg ulcers, also known as "open leg"). Since the shape of the product can be tailored to the shape of the wound by cutting it to size, this prevents the wound from overhanging and thus preventing maceration of the skin surrounding the wound, despite moist wound care. Furthermore, the product can be worn much more comfortably under a compression bandage or compression stocking, such as those used for pressure ulcers to relieve pathological venous congestion. The wound care product according to the present invention is excellently suited for the treatment, in particular for moist wound treatment, of difficult-to-heal or non-healing and chronic wounds.These include, in particular, the following wound types: diabetic foot lesions, venous leg ulcers, arterial leg ulcers, mixed leg ulcers, and decubitus ulcers. These wounds are often characterized by the presence of deposits (e.g., fibrin deposits) and necrosis. Furthermore, the inhibited healing process appears to be associated with an imbalance of the necessary messenger substances, enzymes (e.g., matrix metalloproteases), and molecular inhibitors in the wound. Irrigating the wound as part of moist wound treatment eliminates the previously prevailing chemical imbalance, allowing an environment conducive to wound healing to develop. The previously inhibited healing is thus restarted. As already mentioned, the wound care product according to the invention can be combined with compression therapy in the vast majority of cases to eliminate venous congestion, the underlying ulcer-causing problem.

[0049] According to one embodiment of the invention, the wound care product comprises a backing layer (support layer) located distal to the protective layer. This backing layer can be in the form of a foil or film. The backing layer is preferably in the form of a film. Furthermore, it is preferred that the backing layer contains or consists of polyurethane (PU). PU offers the advantage of being low-noise or even silent (depending on the processing), whereas other synthetic materials often create a stiff and crackling impression and are therefore perceived as unpleasant by some patients.

[0050] Alternatively, the backing layer can be made of a polyolefin such as polyethylene (PE), polyvinyl chloride (PVC), or polyester. A backing layer in the form of a film or foil can significantly reduce evaporation from the swelling layer. This allows the product to remain in place on the wound for a longer time without compromising its functionality in terms of moist wound treatment and the product's characteristic suction-irrigation mechanism.

[0051] The backing layer can be transparent. This allows visual inspection to determine whether the swelling layer has already absorbed the maximum possible amount of wound exudate, thus establishing a stable fluid balance between the wound and the wound care product. If this is the case, the decision can be made to change the dressing. The used wound care product can then be disposed of together with the absorbed wound fluids, pathogens, dissolved deposits, and other components bound to it. After applying a new wound care product according to the invention, the wound is continued to be rinsed with fresh saline solution. In addition, a transparent backing layer can allow an assessment of whether a bacterial infection of the wound has occurred, as this is often accompanied by a change in the color of the exudate.

[0052] According to a preferred embodiment, the backing layer should essentially be as large as the protective layer. According to another embodiment of the wound care product, the backing layer extends beyond the protective layer, thus forming a circumferential adhesive edge. This particularly effectively prevents layers of clothing or therapeutic textiles worn over the wound area (e.g., compression stockings or bandages) from becoming wetted with saline solution or wound exudate and allows for the particularly efficient reabsorption of the portion of the aqueous saline solution released into the wound back into the swelling layer.

[0053] Particularly suitable means for securing the wound care product according to the invention to the wound site are secondary dressings such as adhesive films, gauze, bandages, and roll plasters. Adhesive films are preferred among these because, like the wound care product itself, they can be cut to size without losing function or fraying. Furthermore, adhesive films reduce evaporation and, even when applied to the sole of the foot, do not impede the patient's walking. Furthermore, adhesive films can be made waterproof, thus protecting the wound care product from unwanted external influences (e.g., when showering).

[0054] Particularly preferably, the backing or backing layer is elastic and / or printable and / or impermeable to water and water vapor. Impermeable to water and water vapor in this sense is understood to mean a material whose Moisture Vapor Transmission Rate (MVTR) is below 1000 g / m 2 / 24 h, preferably below 800 g / m 2 / 24 h, even better below 600 g / m 2 / 24 h and preferably below 100 g / m 2 / 24 h. At the same time, the backing can be designed to be waterproof to a water column of 800 mm, preferably 1,300 mm, and ideally 2,000 mm. These values ​​can be achieved, for example, by the backing or backing layer containing or consisting of PU or PET. Thicker films offer a lower MVTR value. The backing layer can, for example, have a thickness (corresponding to a height in the finished product when viewed from the side) of 0.2 mm to 1 mm or 0.3 mm to 0.8 mm. Any adhesive coating is not taken into account in the measurement. An MVTR below 1000 g / m 2 / 24 h can generally be achieved with a layer thickness of just 0.2 mm. The specified MVTR values ​​refer to an aqueous saline solution, preferably an isotonic saline solution, particularly preferably an isotonic Ringer's solution.

[0055] The backing layer can be attached to the support layer using an adhesive. The adhesive can be applied over the entire surface, but a patterned application is preferred, as the untreated gaps allow for better gas exchange. Acrylic adhesive has been shown to result in a particularly stable and permanent attachment, making it the preferred adhesive.

[0056] The nonwoven fabric of the proximal liquid-permeable layer and / or the protective layer can contain thermally bonded fibers. This increases bond strength and simultaneously allows for the creation of lighter nonwovens, resulting in material savings. At the same time, water permeability is maintained. The thermally bonded nonwoven fabric can contain thermoplastic fibers. Examples include polypropylene (PP), polyvinyl chloride (PVC), polyethylene (PE), polyester (PET), polyacrylic (PC), polyacrylonitrile (PAN), polyamide (PA), polyurethane (PU), viscose (CV), and blends of two or more of these fiber types. Furthermore, additional thermoplastic components can be included. One example of a thermoplastic additional component is PET.

[0057] To produce a suitable thermally bonded nonwoven fabric, the resulting loose

[0058] The fibers laid in the nonwoven fabric are heated to their melting point, causing them to bond. Calender bonding (also called thermobonding) or hot air bonding (also called thermofusion) can be used, although calender bonding has proven particularly effective in the case of PP fibers.

[0059] When using fibers that are not suitable for thermal bonding in their pure form, binding fibers can be added to enable thermal bonding nonetheless. In this way, the thermally bonded nonwoven can contain other fiber types such as cotton or viscose in addition to thermoplastic fibers and additional thermoplastic components. These fibers are preferably fibers of natural origin or semi-synthetic fibers such as viscose. Heat transfer for thermal bonding can occur via thermal conduction, convection, or radiation. The calendering and hot air processes are particularly suitable. This type of bonding enables the transformation of a loose fiber nonwoven into a strong, durable nonwoven. The risk of fibers becoming loose and entering the wound is thus greatly reduced.

[0060] The SAF in the swelling layer can comprise a polymer or consist of a polymer containing acrylate. This can be a polyacrylamide or a derivative of a polyacrylamide, or an acrylamide copolymer. According to a preferred embodiment of the invention, the SAF in the swelling layer of the wound care product contains a polymer that is crosslinkable. An example of crosslinkable polymers from which SAF can be obtained or which can form a component of SAF are acrylate-containing polymers or acrylate copolymers.

[0061] The SAF in the swelling layer of the wound care product can preferably contain a cross-linked polymer. The cross-linking is preferably based on the formation of ester bonds. The cross-linked polymer can be cross-linked or cross-linkable through these ester bonds. The degree of cross-linking can be used to adjust the flexibility or resistance of the SAF (flexural moment of resistance) in the presence of the aqueous saline solution. The higher the degree of cross-linking, the tougher the gel-like consistency of the SAF, which can exist as hydrogels in the presence of water or other aqueous fluids such as wound exudate. At the same time, the resilience of the swelling layer and thus of the wound care product as a whole increases with the degree of cross-linking.

[0062] The crosslinking bonds can be acrylic ester bonds. Crosslinking can occur via radical or cationic polymerization mechanisms or other esterification or transesterification mechanisms, such as the Michael addition. Radical polymerization is preferred. Polyacrylamides can be crosslinked by introducing them into an acidic environment. Depending on the desired reaction rate, the pH can be less than 6.0, less than 5.0, or less than 4.0. For example, the pH can range from 3.0 to 6.0, or from 1.0 to 5.0, or from 0.0 to 4.0.

[0063] In this context, the SAFs can contain a polymer that is 5 to 50% crosslinked, preferably 10 to 40%. For acrylic-containing polymers, the degree of crosslinking can be determined based on the amount of acrylic groups crosslinked via ester bonds within the polymer. Thus, with a degree of crosslinking of 50%, half of the acrylic groups would be crosslinked.

[0064] Furthermore, the SAF may contain a copolymer, which may be an acrylic copolymer.

[0065] One possible example is poly(acrylic acid-co-acrylamide) / polyvinyl alcohol. This can be spun directly into SAF.

[0066] The cross-linking of SAF does not preclude its needlepunching with at least one other fiber type (an additional fiber that is not SAF) to create a needlefelt. Cross-linking can take place either before or after needling, although it is recommended to perform it before needling, as this allows for more precise adjustment of the degree of cross-linking. Thermal bonding can follow needling; these three processes (cross-linking, needling, and thermal bonding) complement each other synergistically, resulting in a swelling layer that exhibits excellent moisture retention, moisture release, and excellent mechanical strength, even after cutting by the end user or caregivers.

[0067] The ratio between SAF and additional fiber in the swelling layer can, for example, be as follows: 20 wt.% to 80 wt.% SAF and 80 wt.% to 20 wt.% additional fiber. The proportion of SAF in the swelling layer is preferably 20 wt.% to 60 wt.%, particularly preferably 20 wt.% to 40 wt.%, with the remaining proportion being provided by the additional fibers. One possible embodiment contains 25 wt.% SAF and 75 wt.% polyolefin-based fibers in the swelling layer.

[0068] According to the invention, the liquid-permeable layer, the swelling layer, and the protective layer are bonded to one another over their entire surface (i.e., over the entire area of ​​the respective top and bottom sides). The surfaces can be bonded to one another adhesively, whereby the adhesive connection of the surfaces can be designed directly (directly adjacent) or indirectly - e.g., by inserting further intermediate layers such as a perforated, double-sided adhesive film or a porous melt film (thermoplastic). The layers can be joined or bonded together adhesively, for example, by an adhesive or an adhesive bond. The adhesive bond or adhesive layer can be present in the finished product as a cohesive layer, i.e., within it, the particles of the adhesive (atoms, molecules, etc.) attract one another. Preferably, it is a hot-melt adhesive or a hot-melt adhesive bond.Examples of possible hot melt adhesives are copolymers and polyolefin-based hot melt adhesives such as polyester or polyester derivatives such as co-polyester. Such hot melt adhesives are ideal for permanently joining nonwoven layers, particularly those containing synthetic fibers. They are also generally technically compatible with subsequent heat sterilization. The melting point can also be below the subsequent sterilization temperature, as the product is already in outer packaging during sterilization, which gives the product additional stability. The melting point of the hot melt adhesive or hot melt adhesive compound can, for example, be between 45 °C and 120 °C, preferably between 45 °C and 70 °C. If necessary - e.g. through the use of co-polyester - maximum melting points of up to 140 °C and sometimes even higher can be achieved.It is recommended to sterilize the wound care product in a moist state (i.e. with the aqueous saline solution it contains), since in this way low sterilization temperatures (e.g. 120 °C) may already be sufficient, provided that a sufficient exposure time is ensured.

[0069] The above-mentioned hot melt adhesives can be added to the melting process in various starting materials. This makes it possible to provide the hot melt adhesive in the form of particles, as a mesh, or as a film. Providing the adhesive in the form of particles or a mesh is preferred because it does not restrict the mobility of the resulting product. Particles also offer the advantage of flowability. Films and meshes are particularly suitable when different hot melt adhesives are to be combined. Hot melt adhesive combinations can lead to particularly strong adhesive bonds, with one of the adhesives used fixing the respective layers during the manufacturing process, and the other adhesive (with a higher melting point) reacting during the sterilization process and further strengthening the initial bond without the need for additional thermal energy during the process.

[0070] The layers of the wound care product—particularly the fluid-permeable layer, the swelling layer, and the protective layer—can be present as a laminate, whereby additional layers such as an adhesive carrier (proximal) or a backing (distal) can also be incorporated and then become part of the laminate. These can be bonded together either using thermal energy and / or adhesives. Using adhesives that are not heated also creates a laminate, which in this case is a cold laminate. It is recommended to apply the aforementioned hot melt adhesive between the layers to make the resulting laminate more durable. The required temperatures depend on the materials to be treated and can, for example, range from 45–160°C. A contact time of 2 seconds to 10 minutes is usually sufficient.The optimal exposure time varies depending on the selected temperature, but in most cases will be in the range of 2 to 30 seconds.

[0071] The layers of the wound care product, which are adhesively joined in this way, have the advantage of forming a flat bond that continues to hold the layers together even after the product has been trimmed. This flat bond is preferably a full-surface adhesive bond, particularly preferably a full-surface adhesive bond, and ideally a full-surface hot-melt bond. Conversely, methods that only join the individual layers along their edges (e.g., conventional welding) do not result in a product that can be cut to size.

[0072] Other ways to connect the layers together include anchoring fibers from one layer into an adjacent layer. In this way, two layers can be connected, for example, by weaving or felting.

[0073] The wound care product can be cut into two or more segments. All segments obtained in this way can be used in wound care. The segments obtained by cutting are capable of releasing the aqueous saline solution stored in the swelling layer into the wound, thereby irrigating and cleansing it.

[0074] A further aspect of the invention relates to a cuttable, flat wound care product in which the fluid-permeable layer, the swelling layer, and the protective layer are joined together via a fusion bond, and wherein the fusion bond contains or consists of a fused polyolefin or fused copolymer. Such a laminate can advantageously be cut to size without fraying at the cut edges.

[0075] A particular advantage of the cuttable, flat wound care product according to the invention is that the rinsing effect emanating from the wound care product is reinforced or intensified upon repeated reversible (non-plastic) deformation or repeated pressure compression of the wound care product. This can be achieved in practice, for example, by applying the wound care product to the sole of the foot and then repeatedly applying and releasing pressure when walking by the patient or end user. In this way, the wound care product is compressed by body weight upon walking, and the portion of the aqueous saline solution not firmly bound to the SAF is partially forced out of the wound care product. As soon as the patient lifts their foot and the wound care product expands again, a portion of the released saline solution (together with dissolved substances, pathogens, etc.) is reabsorbed.This process takes place repetitively while walking, which allows for particularly intensive irrigation of the wound.

[0076] Another option, for example, when treating an open leg, is to apply the wound care product and then wrap it with a compression bandage. The compression bandage acts as a counterforce to the so-called venous-muscle pump. The wound care product is compressed between the body surface and the compression bandage during muscle contraction. During subsequent muscle relaxation, the wound care product can expand again. Muscle tension occurs involuntarily when walking. If a patient is bedridden, suitable exercises can alternatively be performed while lying down – for example, under the supervision of a physiotherapist. A beneficial, enhanced irrigation effect also occurs in the cases mentioned here.

[0077] For the purposes of this aspect (enhanced irrigation effect), the term repeated reversible deformation or repeated pressure compression can mean that the wound care product is capable of enhanced irrigation of the wound if it is deformed or compressed at least three times and each time essentially returns to its original shape without additional assistance. Enhanced irrigation is understood to mean irrigation in which a larger volume of aqueous saline solution is delivered (e.g., to a wound or a measuring device) compared to purely passive mass transfer (without deformation or compression) along the concentration gradient. In this case, the wound care product can, in its initial state, be saturated with the aqueous saline solution to, for example, 80% of its maximum absorption capacity.

[0078] In the context of the invention, the wound care product is capable of generating a muscularly driven pumping effect during wound treatment to irrigate the wound to be treated with the aqueous saline solution contained in the swelling layer, particularly during walking when the product is attached to the sole of the foot. The thus intensified irrigating effect enables extremely gentle cleansing of the wound of necrosis and fibrin deposits, thus generally avoiding invasive surgical cleansing using a scalpel, sharp spoon, etc., which is stressful for the patient.

[0079] Preferably, the enhanced rinsing effect simultaneously represents an enhanced suction / irrigation effect, which is accompanied by increased absorption of substances absorbed from the wound. For example, microorganisms flushed from the wound are retained in the effervescing layer and removed during the next dressing change.

[0080] Furthermore, it can be provided that after cutting the wound care product according to the invention, the structural integrity of the remaining area intended for wound care is maintained, so that no fibrous or particulate components of the cut wound care product, in particular no superabsorbent fibers, are released through the felt structure of the swelling layer. Such a wound care product is thus lint-free, even after cutting immediately before use.

[0081] In the wound care product according to the invention, it can be provided that the pH of the aqueous saline solution of less than 7.0 is mediated by an acid group contained in the superabsorbent fibers, preferably by acrylic acid. This acid group can be part of the polymer contained in the SAF or from which the SAF consists. The polymer can be polyacrylic acid. The advantage is that further components for acidification can be dispensed with and a pH value in the slightly acidic range that promotes healing for the vast majority of wounds can be set. The pH of the aqueous saline solution mediated by said acid group is preferably in the range of 4.5 to 6.9. The pH value is particularly preferably in the range of 5.0 to 6.5.

[0082] Furthermore, it is preferably provided that the liquid-permeable layer, the swelling layer, and the protective layer exhibit a substantially identical lateral increase in size upon absorption of liquid. Substantially identical lateral increase in size means that the areal expansion of these layers increases to the same extent when they absorb moisture, whereby small differences in area (after expansion) of up to 5%, preferably up to 3%, between the adjacent layers are possible and included. The expansion can be determined according to the AATCC TM 135 standard. Regarding any possible shrinkage after liquid release, this applies analogously to the reduction in the area of ​​the layers.

[0083] The advantage of an essentially equal change in the surface area of ​​the three layers upon contact with liquid is that moisture absorption does not lead to deformation (e.g. curvature or bulging) of the wound care product and the planar shape is maintained.

[0084] In this context, the fluid-permeable layer, the swelling layer, and the protective layer can also have the same or essentially the same thermal lateral expansion coefficient, which refers to the surface area. Differences of up to 5%, preferably up to 3%, between the adjacent layers are included as tolerances. An identical or essentially identical thermal lateral expansion coefficient offers an advantage during heat sterilization of the wound care product. Otherwise, undesirable deformation of the product may occur during sterilization, and sterilization must be performed using other (usually more complex or expensive) methods, such as irradiation or fumigation with ethylene oxide.

[0085] Identical or essentially identical expansion or thermal expansion can be achieved by using multiple layers of materials that exhibit the same or very similar expansion behavior. For example, synthetic fibers exhibit very similar expansion and shrinkage behavior both among themselves and compared to cotton.

[0086] According to the invention, the swelling layer of the wound care product comprises at least one other fiber type or at least one additional fiber in addition to SAF. This is advantageously a cellulose-containing fiber such as lyocell, a polyolefin-based fiber, a polyester-containing fiber, preferably polyethylene terephthalate, and / or a polyamide-containing fiber.

[0087] Lyocell fibers have the advantage of excellent moisture retention, exceeding the already high capacity of cotton. Thus, lyocell fibers synergistically support the SAF, providing the necessary structural strength to the swelling layer and keeping the SAF in place within the swelling layer.

[0088] Furthermore, with regard to the wound care product according to the invention, it is possible for the nonwoven fabric of the liquid-permeable layer and / or the protective layer to contain viscose and polyester or to consist of these polymers. The polyester content in the nonwoven fabric can be, for example, 30 to 50 percent by mass. The addition of the hydrophobic polyester creates a hygroscopic gradient from both the liquid-permeable layer and the protective layer, which conducts liquid through the latter two layers toward the swelling layer. At the same time, the aqueous saline solution coming from the swelling layer can pass through the liquid-permeable layer and then enter the wound without being retained in the liquid-permeable layer.

[0089] Furthermore, it is possible for the liquid-permeable layer and the protective layer to be made of an identical material or material blend and / or have the same basis weight. These can be the materials or material blends listed in the last paragraph. Using identical materials for both layers can simplify and accelerate the production process, as both layers can be processed using the same machine type.

[0090] In general, it is possible that the nonwoven fabric of the liquid-permeable layer and / or the protective layer has a basis weight of 15 to 50 g / m 2 , for example 18 to 45 g / m 2, has. The basis weight can be determined according to the DIN EN 12127 standard. It has been shown that layers of this type combine excellent structural strength with high fluid permeability. The layers remain resilient even after possible cutting, but do not impair the desired absorption / irrigation effect of the wound care product.

[0091] Depending on the intended application, it may be advantageous to equip or coat the nonwoven fabric of the liquid-permeable layer proximally with a silicone or silicone-containing material. In this sense, the liquid-permeable layer of the wound care product according to the invention can be at least partially coated on its proximal side with silicone or silicone-containing material. These substances can be applied to the nonwoven fabric of the liquid-permeable layer (proximal side). The silicone-containing material can be, for example, a silicone-based adhesive or a silicone gel, which does not harden after application and thus acquires adhesive properties.

[0092] In this sense, the invention comprises a version of the wound care product, wherein the wound care product has an additional silicone-containing wound contact layer, which is attached directly or in the form of a coated film to the outside of the liquid-permeable layer (i.e. in the proximal direction).

[0093] It is not recommended to provide the finished wound care product with a fully covered or coated fluid-permeable layer, as this would impede fluid exchange due to the hydrophobic properties of the silicone. Instead, the layer can be applied in a patterned manner – e.g., in dots or stripes, with the stripes arranged parallel to one another. Alternatively, the layer can be applied over the entire surface and the silicone or silicone-containing material can then be perforated. This full-surface coating with perforations offers the advantage over patterned applications that, regardless of the type of subsequent cutting, the edges of the fluid-permeable layer are always coated, ensuring the entire edge has the same height.

[0094] Alternatively, the silicone or silicone-containing material can be attached to the liquid-permeable layer via a foil or film. The foil or film can contain or consist of PU. They are coated on the distal side with an adhesive such as an acrylic adhesive. The adhesive-coated foil or film is also referred to in the context of this invention as an adhesive carrier. The distally located adhesive does not necessarily have to be skin-compatible. The opposite side of the foil or film (proximal side) is coated with the aforementioned silicone or silicone-containing material. The use of the film or foil offers the advantage that it can be kept in stock as a mass product (e.g., roll material) and can be quickly and automatically attached to the proximal side of the liquid-permeable layer as needed during the manufacturing process.The film or foil forms a stable bond with the fluid-permeable layer. If the film or foil is fully coated on the proximal or distal side, it is recommended to provide the adhesive carrier with continuous perforations before application to the fluid-permeable layer. Continuous means that the perforations penetrate both the film or foil and both coatings, allowing subsequent mass transfer via the fluid-permeable layer.

[0095] Furthermore, the adhesive carrier configured in this way can be applied to the liquid-permeable layer over the entire surface or in a pattern (e.g., in the form of stripes or dots). In this sense, the invention encompasses a wound care product comprising a silicone-containing wound contact layer that only partially overlies the liquid-permeable layer, and wherein the silicone-containing wound contact layer is preferably perforated.

[0096] If the silicone or silicone-containing material or film is to be perforated, it is important to ensure that the perforations are sufficiently large. For example, a perforation can cover an area of ​​0.05 mm 2 up to 7.00 mm 2 with preference given to larger perforation areas. For example, the average area per perforation may be 0.8 mm 2 up to 7.00 mm 2 or 0.8 mm 2 up to 6.00 mm 2 amounts.

[0097] The perforations can have different shapes or contours, with circular or oval perforations offering the advantage of providing good resilience when stretching or bending the wound care product without tearing. At the same time, the absence of edges or corners provides a more pleasant skin feel and reduces the risk of irritation to the wound area.

[0098] An open (uncoated) area of ​​the liquid-permeable layer in the range of 10% to 25% or 12% to 23% of its total area is advantageous. The open area can be achieved through the perforations mentioned above or by applying the coating in a pattern.

[0099] It is recommended to apply the coating as thinly as possible, as this saves material without compromising quality. Good results are achieved with a coating quantity of 100 g / m 2 up to 200 g / m 2, preferably 120 g / m 2 up to 175 g / m 2 and particularly preferably 135 g / m 2 up to 160 g / m 2 The specifications apply to the coating of both nonwoven material and film, prior to any perforation. For sample-based applications, the specified coating application areas may be correspondingly smaller, e.g., reduced by 25%.

[0100] The silicone or silicone-containing material with which the nonwoven fabric or film can be coated is, for example, a silicone adhesive or a silicone-containing adhesive or a silicone gel. Such adhesives or gels offer the advantage that they can fix the wound care product to the wound or wound area and are atraumatic. This means that they can be removed painlessly and without damaging newly formed tissue. The wound care product according to the invention can have different external shapes and dimensions. For the treatment of an (external) wound, a shape that is flat on both sides (i.e. both proximal and distal) is recommended. For the treatment of ulcers on the sole of the foot, it is also advantageous to design the wound care product with a low height.This type of wound care product hardly or not at all disrupts the patient's normal daily routine, as the patient can wear the product under socks and in shoes and even walk with it. Such a low height is 1.5 mm to 6 mm. Within this range also lies a wound care product design that features an adhesive carrier (proximal) and a backing (distal). Should the wound care product only have the minimum structure of a protective layer, swelling layer, fluid-permeable layer, and optional adhesive layers, the height can be even more advantageous: 1.7 mm to 3 mm, preferably 1.7 mm to 2.5 mm, and particularly preferably 1.8 mm to 2.2 mm.The specified height ranges refer to the dry composite described in the present application (i.e., without aqueous saline solution) comprising the liquid-permeable layer, swelling layer, and protective layer, and also without optional release liners or other packaging material. The height of the product treated with the aqueous saline solution can typically increase by about 10% (depending on the applied volume) compared to the dry product. Consequently, the wound care product in the moist state would, for example, have a height of 1.7 mm to 6.6 mm, more preferably 1.9 mm to 3.3 mm, even more preferably 1.9 mm to 2.8 mm, and most preferably 2 mm to 2.4 mm.

[0101] Examples of other possible shapes include cushion-shaped and cylindrical. The cushion-shaped version provides a particularly good cushioning effect. This is particularly comfortable for patients, for example, in the case of wounds on the ankle. The cylindrical version is particularly advantageous for tunnel-shaped wounds and cavities, where any protruding end (protruding from the wound) can simply be trimmed off. This prevents premature superficial wound closure with underlying encapsulation and subsequent abscess formation.

[0102] In terms of shape, the wound care product can be round, rectangular, square, oval, or diamond-shaped when viewed from above. The surface area can, for example, be 50 cm 2 up to 500 cm 2, whereby larger surfaces offer the advantage of being able to be tailored to the respective wound size. The swelling layer of the wound care product preferably contains the aqueous saline solution in an amount that does not exhaust its absorption capacity. This means that the swelling layer is preferably not saturated or unsaturated. In this way, the swelling layer or the wound care product can absorb further fluid such as wound exudate or blood. It is therefore possible for the swelling layer or alternatively the entire wound care product to be saturated with the aqueous saline solution to a maximum of 50%, a maximum of 60%, a maximum of 70%, a maximum of 80%, a maximum of 90% or a maximum of 95%.

[0103] It is possible to adjust the swelling layer in its composition, density and / or thickness (height extension) in such a way that at least 30 g, better at least 35 g, even better at least 38 g and best of all at least 40 g of Ringer's solution per 100 cm 2The swelling layer area must be absorbed within 10 minutes from a flat container with a Ringer solution filling height of 2 mm and a total Ringer solution volume of at least 50 ml.

[0104] The fluid release of the swelling layer or wound care product (in terms of the intended wound irrigation effect) can be at least 8 wt.%, better at least 10 wt.%, even better at least 13 wt.%, and most preferably at least 15 wt.% of the maximum absorption capacity of the swelling layer or wound care product. The method for determining fluid release is described in the examples.

[0105] The fluid retention capacity of the swelling layer or wound care product can be at least 60 wt.%, better at least 70 wt.%, even better at least 80 wt.%, and most preferably at least 90 wt.% of the maximum absorption capacity of the swelling layer or wound care product. The method for determining the fluid retention capacity is shown in the exemplary embodiments.

[0106] Which of these values ​​is most suitable depends on the type of wound being treated. The more heavily a wound is covered with deposits (e.g. fibrin deposits), necrotic tissue, or biofilm, the more it will benefit from intensive irrigation, so high saturation values ​​of 80% or more are recommended in such cases. In contrast, heavily exuding, non-infected wounds can be treated with variants of the product that have a lower saturation in the range of 50% to 70%. The specified saturation values ​​are explained below using an example: If the swelling layer can absorb a maximum of 100 ml of an aqueous saline solution (osmotic value in the isotonic range, i.e. 9 g NaCl per liter H2O), the swelling layer is 50% saturated after absorbing 50 ml.

[0107] Furthermore, the specified saturation values ​​can also refer to a wound care product with the three main layers (protective layer, swelling layer, fluid-permeable layer and intermediate adhesive layers) or to the entire wound care product, which can also have additional layers (e.g. backing layer) as required.

[0108] Furthermore, it may be determined that the wound care product is not suitable or compatible with negative pressure therapy because, for example, it does not have a port through which negative pressure can be applied to the product or a wound underneath the product.

[0109] Within the scope of the present invention, it can be provided that the wound care product contains no superabsorbent particles. Preferably, it contains no particles at all that could fall out after the product has been cut to size. Exceptions to this are adhesive particles that can be used during the manufacture of the product, as these bond with the other materials and do not impede the desired effect of being cut to size. Active ingredient particles that dissolve in the aqueous saline solution are also not excluded from the inventive concept.

[0110] The salt present in the aqueous saline solution can be NaCl. The aqueous saline solution is preferably isotonic. Such an isotonic saline solution has essentially the same osmotic pressure as human blood. Minor deviations in the pressure value of 1% in Pascal, either up or down, are tolerable and also fall under the term "isotonic solution."

[0111] In addition to NaCl, the aqueous saline solution can also contain other salts such as KCl or salt combinations such as KCl and NaCl. A preferred variant of the aqueous saline solution is the so-called Ringer's solution, which contains CaCl in addition to NaCl and KCl and is isotonic.

[0112] An isotonic solution offers the advantage that the unprotected cells in the open area of ​​the wound to be treated are not exposed to osmotic stress. Rather, the supply of minerals contained in the saline solution has a positive effect on cell metabolism. Human cells are able to

[0113] Proteins such as aquaporins absorb minerals from the environment.

[0114] In this sense, the aqueous salt solution can contain NaCl, KCl and CaCl.

[0115] The aqueous saline solution stored in the swelling layer can permeate from the swelling layer into the other layers of the wound care product. In particular, the aqueous saline solution can be present in both the protective layer and the fluid-permeable layer. This does not impair the functionality of the product. Permeation of the solution through the fluid-permeable layer, at the latest after application to the wound, is actually desirable. When determining the amount of solution required to wet the swelling layer, the absorption capacity of the other layers can be taken into account.

[0116] In the following, the invention will be explained in more detail with reference to exemplary drawings, whereby the variants shown can be modified depending on the intended use with the help of the technical information contained in this document.

[0117] Figure 1 shows a cross-sectional view of an embodiment of the wound care product according to the invention, which can be adhered to a wound and / or skin and also features a liquid-tight backing. This variant is ideally suited for the treatment of ulcers on the sole of the foot, among other things.

[0118] Figure 2 shows the product of Figure 1 in a cut-out form in top view.

[0119] Figures 1 and 2 show a wound care product (9) according to the invention, comprising an upper backing (5) which minimizes the escape of the aqueous saline solution (not shown) from the swelling layer (3) in the distal direction and simultaneously functions as a support layer for the wound care product (9). The backing (5) is attached to the protective layer (1) made of nonwoven fabric by means of an adhesive layer (2). The protective layer (1) is connected to the swelling layer (3) by means of an adhesive layer (2). Below the swelling layer (3), the proximally located liquid-permeable layer (4) is attached by means of an adhesive layer (2). The liquid-permeable layer (4) is overlaid in the proximal direction by a perforated adhesive carrier.This consists of an adhesive layer (2), which forms the connection to the liquid-permeable layer (4), a PU film (6), and a layer of atraumatic silicone adhesive (7). The perforated adhesive carrier is provided with perforation openings (8) over its entire surface, which extend through the silicone adhesive (7), the PU film (6), and the adhesive layer (2). The product can be fixed to the skin, the wound, or the wound edges using the silicone adhesive (7), with the PU film and silicone adhesive acting as the wound contact layer. In the illustration in Figure 2, the wound care product (10) is cut in the middle into two halves (segments). The structural unity and functionality of each half are maintained.

[0120] Fig. 3 shows the fluid release of the wound care product according to the invention and a control wound dressing within 24 hours and 72 hours in a bar chart. The wound care product is symbolized by solid black bars, while the control product is symbolized by contoured bars. Further details can be found in the corresponding exemplary embodiment.

[0121] Fig. 4 shows the fluid retention capacity of the wound care product according to the invention using a bar chart. Further details can be found in the corresponding exemplary embodiment.

[0122] Figure 5 shows the absorbency of the wound care product according to the invention and a control wound dressing in a bar chart. The wound care product is symbolized by a solid black bar, the control by a contoured bar.

[0123] Examples

[0124] The invention is explained in more detail below using exemplary embodiments:

[0125] Example 1: Manufacture of an adhesive wound care product for application to the skin surface

[0126] First, a swelling layer (3) was provided by the meter. A proximal, liquid-permeable layer (4) in the form of a PP nonwoven was attached to the underside of the swelling layer (3). A distal protective layer (1), also made of a PP nonwoven, was attached to the top of the swelling layer (3). To secure the layers together, adhesive particles in the form of biodegradable polyester were applied between the layers. The adhesive particles were then bonded together in a subsequent thermal bonding process. This was achieved by thermal treatment in a drying oven at a temperature of more than 120°C, followed by roller compression. The fused adhesive particles each formed an adhesive layer (2). The resulting three-layer laminate had a basis weight of 260 g / m². 2with a thickness of 2.3 mm. This laminate was wound onto a roll and placed in a converting machine. In the next step, a backing layer (5) made of PU was applied to the upper side (the distal side when applying the wound care product) of the laminate using an acrylic adhesive. In addition, a perforated adhesive carrier was applied proximally to the fluid-permeable layer. This adhesive carrier consisted of a PU film (6), the underside of which was coated with skin-compatible and atraumatic silicone adhesive (7). The top side of the PU film was coated with an acrylic adhesive (2), which bonded the PU film to the fluid-permeable layer. The PU film and acrylic adhesive together formed the adhesive carrier. The silicone adhesive (7) and PU film (6) formed the wound contact layer.The perforation openings (8) in the adhesive carrier and the silicone adhesive ensured that subsequent passage of liquid was guaranteed.

[0127] To protect the silicone (7), it was covered with a release liner, which must be removed immediately before applying the product to a wound. The backing layer (5) was printed with a pattern intended to clarify to the future user that this was the top side of the product, thus facilitating correct application.

[0128] In the next step, square sections measuring 10 cm x 10 cm were cut out of the laminate. The separated products were then processed using a packaging machine. In the packaging machine, the previously dry products were spread out on a liquid-tight packaging film. Aqueous saline solution was added in an amount that did not exhaust the maximum absorption capacity of the products (approximately 31 ml). This was followed by sealing with an upper packaging film (liquid-tight), so that the wound care products (9) were enclosed between the lower and upper films. The resulting bag and its contained products were then steam sterilized at 120°C. The now moist wound care products (9) were then stored in a sterile manner in the bag, which also served as part of the packaging material.The sterile products thus obtained can be removed from the bag and applied to a wound to be treated.

[0129] Example 2: Cutting the wound care products. The wound care product (9) according to Example 1 was cut in half approximately in the middle (i.e., approximately 5 cm from the left and right edges) using standard scissors. The cutting process was performed effortlessly and without any particular force. The cut edges were visually assessed. No fraying or loose fibers were observed. The cut surfaces were even, smooth, and straight.

[0130] Furthermore, the layers of the cuts continued to form a stable bond and showed no tendency to separate, disintegrate, or delaminate. Thus, each individual cut was suitable for use in wound care.

[0131] Example 3: Measurement of maximum pressure load

[0132] A moist wound care product (9) approximately two weeks old, as described in Example 1 – but in a circular shape – was prepared and placed in a commercially available transparent plastic ZI P bag. The bag was sealed and placed in a calibration device from Sensomative for further testing. The (viewed from above) radial wound care product (9) had a diameter of 4.5 cm. Loading cycles were then performed, each of which applied a weight force of 188.5 N (corresponding to approximately 19 kg) to the entire surface of the product (9) within 1 second. The weight force was maintained for 1 second and then reduced to 0 N within 2 seconds. The number of loading cycles was ten. The process took place at a temperature between 22°C and 23°C.The weight force was transmitted using an inflatable envelope made of synthetic, airtight material installed in the calibration device. The envelope was pneumatically inflated during the loading cycles.

[0133] After the stress test was completed, the product (9) was removed from the system. Both the product (9) and the bag were visually inspected. No material breakage was observed. All layers of the product (9) were structurally intact. After removing the product (9) from the bag, no torn fibers or leaked gel were visible on the product (9), nor were any separated or leaked materials found inside the bag. Only a small amount of the aqueous saline solution remained in the bag.

[0134] Example 4: Determination of fluid delivery Fluid delivery is crucial for the intended wound irrigation effect.

[0135] A swelling layer described in Example 1 was prepared in a circular design with a diameter of 4.5 cm. As stated in Example 1, the swelling layer contained Ringer's solution without being saturated with it. After determining the weight of the swelling layer (r ), it was placed on a hydrogel dressing ("HydroTac transparent™" from HARTMANN, cut to the approximate area of ​​the swelling layer). The swelling layer lay on the wound contact surface of the hydrogel dressing and thus had contact with the hydrogel. The hydrogel dressing simulated the plasticity and fluid absorption capacity of human tissue. Both components were then shrink-wrapped together in a vapor-impermeable film. In the next step, a cardboard box approximately the same size as the hydrogel dressing was placed on top of the welded combination of swelling layer and hydrogel dressing. An Erlenmeyer flask filled with water was placed inside the cardboard box.The carton and filled plunger together weighed 250 g, simulating the contact pressure of a secondary dressing. The weight of the wound dressing (m²) was determined after 24 and 72 hours. The fluid output of a total of 40 specimens (20 per period) was tested, and the average value was calculated.

[0136] The control was a moist wound dressing described in WO 2016 / 156619 A1 with the following structure: a wound dressing with a nonwoven-based absorbent / irrigating body containing superabsorbent particles mixed with cellulosic and thermoplastic fibers. The absorbent / irrigating body was provided with a covering forming the outer visible sides of the wound dressing. The covering consisted of a knitted textile fabric on the wound-facing side and a nonwoven fiber layer on the nonwoven side. A liquid-impermeable plastic film layer was placed between the nonwoven fiber layer and the absorbent / irrigating body. The knitted fabric, the absorbent / irrigating body, the plastic film layer, and the nonwoven fiber layer were not bonded to one another over the entire surface, but were held together merely by a welded joint along their peripheral edges. The control was also saturated with Ringer's solution. Forty test specimens were also tested, and the mean values ​​were determined.

[0137] The liquid release [%] was determined using the following formula: 100% - (m2 x 100%) / nm.

[0138] The results are shown in Fig. 3. Example 5: Determination of liquid retention capacity

[0139] Fluid retention capacity is important to prevent the wound care product from being completely squeezed out. To ensure continuous fluid exchange between the wound care product and the wound, providing a suction / irrigation effect, residual fluid should remain in the wound care product even under pressure. The pressure of 35 mmHg applied during the subsequent measurement corresponds to the force typically applied during compression therapy (often used in the context of a leg ulcer to treat venous insufficiency).

[0140] A swellable layer was prepared as described in Example 1, in a circular configuration with a diameter of 4.5 cm. As stated in Example 1, the swellable layer contained Ringer's solution without being saturated with it. First, the weight of the swellable layer (r ) was determined. The swellable layer was placed on a grid. The grid was held in the air using four identical spacers. A weight of 760 g was placed on the swellable layer. After 10 minutes, the swellable layer was weighed again.

[0141] Retention was determined using the following formula: (m2 x 100%) / nm. Twenty samples were tested, and the measured values ​​were averaged. The results are shown in Fig. 4.

[0142] Example 6: Determination of absorption performance

[0143] Absorption capacity is a measure of the absorbency of a wound care product. This absorbency allows pathogens, fibrin deposits, and excess matrix metalloproteases, for example, to be absorbed and trapped within the wound care product.

[0144] A wound care product was prepared as described in Example 1 (circular, diameter 4.5 cm). As stated in Example 1, the product contained Ringer's solution without being saturated with it. After determining the weight, the product was placed in a desiccator containing a drying agent. A 0.9% solution of NaCl in water was poured into the desiccator. The desiccator was closed and a vacuum was applied for 30 minutes. After this time, the product was removed and hung up to drain for 5 minutes. The weight of the product was then determined again. The measurement was carried out on a total of ten products, and the mean value was determined. To determine a comparison value, ten control wound dressings were also measured in the same way as described in Example 4, and the mean value was also determined here. The results are shown in Fig. 5.

Claims

Patent claims 1. A cuttable wound care product (9), comprising a) a proximal liquid-permeable layer (4) comprising a nonwoven fabric, b) a distal protective layer (1) comprising a nonwoven fabric, c) a swelling layer (3) in the form of a nonwoven fabric comprising superabsorbent, polymer-containing fibers located between the proximal liquid-permeable layer (4) and the distal protective layer (1), wherein the superabsorbent fibers are present in a felt with at least one other fiber type, d) an aqueous salt solution which is embedded in the swelling layer (3), has a pH < 7.0 in the embedded state and can be delivered to a wound during wound treatment, wherein the proximal liquid-permeable layer (4), the swelling layer (3) and the distal protective layer (1) have an identical cut and lie against one another over their entire surface without any overhang, and wherein the wound care product (9) is designed to be seamless. is..

2. Cuttable wound care product (9) according to claim 1, wherein the wound care product (9) has a pressure resistance to a pressure of at least 8 kg / 100 cm 2 so that the wound care product (9) is only elastically deformed by the action of such pressure.

3. Cuttable wound care product (9) according to claim 1 or 2, wherein the other fiber type is selected from the group consisting of: cellulose-containing fiber, polyester-containing fiber, preferably polyethylene terephthalate and / or polyamide, and wherein the other fiber type is needled to the superabsorbent, polymer-containing fibers so that it is present in a needle felt.

4. Cuttable wound care product (9) according to one of the preceding claims, wherein the nonwoven fabric of the proximal liquid-permeable layer (4) and / or the distal protective layer (1) contains thermally bonded fibers.

5. Cuttable wound care product (9) according to the preceding claim 4, wherein the thermally consolidated fibers contain or consist of one or more polymers selected from polypropylene, polyvinyl chloride, polyethylene, polyethylene terephthalate, polycarbonate, polyamide, polyurethane, polystyrene, and mixtures thereof.

6. Cuttable wound care product (9) according to one of the preceding claims, additionally comprising a backing layer (5) located distal to the protective layer (1), which backing layer preferably contains polyurethane.

7. Cuttable wound care product (9) according to claim 6, wherein the backing layer (5) is elastic, printable and liquid-impermeable and wherein the MVTR is below 1000 g / m 2 / 24h.

8. Cuttable wound care product (9) according to one of the preceding claims, wherein the superabsorbent fibers in the swelling layer (3) contain a polymer, preferably an acrylate-containing polymer or an acrylate copolymer, which is cross-linkable, wherein the cross-linkability is preferably based on the formation of ester compounds.

9. A cuttable wound care product according to any one of the preceding claims, wherein the proximal liquid-permeable layer (4), the swelling layer (3) and the distal protective layer (1) are present as a laminate.

10. Cuttable wound care product (9) according to one of the preceding claims, wherein the proximal liquid-permeable layer (4), the swelling layer (3) and the distal protective layer (1) are permanently bonded to one another over their surface, wherein the layers are preferably joined together by a hot-melt adhesive, and wherein the hot-melt adhesive preferably contains or consists of a polyolefin or copolymer.

11. Cuttable wound care product (9) according to one of the preceding claims, wherein the structural integrity of the wound care product (9) is maintained during cutting, so that no fibrous or particulate components of the wound care product (9), in particular no superabsorbent fibers, are released through the felt structure of the swelling layer.

12. Cuttable wound care product (9) according to one of the preceding claims, wherein the wound care product (9) has an additional silicone-containing wound contact layer (7) which is attached directly or in the form of a coated film (6) to the outside of the liquid-permeable layer (4).

13. Cuttable wound care product (9) according to claim 12, wherein the silicone-containing wound contact layer (7) only partially overlies the liquid-permeable layer (4) and is preferably perforated.

14. Cuttable wound care product (9) according to one of the preceding claims, wherein the nonwoven fabric of the first proximal liquid-permeable layer (4) and / or the protective layer (1) has a basis weight of 15 g / m 2 up to 50 g / m 2 has.

15. Cuttable wound care product (9) according to one of the preceding claims, wherein the first proximal liquid-permeable layer (4) and the distal protective layer (1) consist of an identical material or an identical material mixture.

16. Cuttable wound care product (9) according to one of the preceding claims, wherein the swelling layer (3) is not saturated with the saline solution stored therein.

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