Patent Application
20120010584
The invention concerns an absorption body to be placed onto a wound and comprised of a layered body of a multi-layer construction, comprising a layer A that is facing the skin, a layer B that is facing away from the skin, and an absorbent body or core that is arranged between these layers A and B.
Absorption bodies for absorbing bodily liquids are not only used in hygiene but also in medicine, in particular for treatment of wounds.
Absorption bodies that are used as wound pads are generally placed onto an external wound in order to prevent penetration of foreign bodies into the wound and to absorb blood and ichor.
U.S. Pat. No. 7,335,809 B2 discloses an absorption body for placement on wounds, in particular for absorbing ichor. The illustrated absorption body comprises a flat material section of absorption material, i.e., an absorbent nonwoven with superabsorbent particles distributed therein, as well as a liquid-permeable envelope. This liquid-permeable envelope surrounds the material section of absorption material and forms a barrier against solid body secretions and prevents passage of other excreted substances into the absorbent material arranged within the envelope. The material section of absorption material has a surface that is smaller than the surface of the envelope, i.e., in the unwetted state 3% to 75% of the laid-flat envelope. The surface of the laid-flat envelope is moreover delimited by a seam and optionally by a folded edge. The envelope and/or the absorption material can be provided at its/their circumference with a substance that adheres to the body of the patient, such as an adhesive. As a suitable adhesive, pectin-cellulose compounds are mentioned.
The wound pads disclosed in the prior art have the disadvantage that they must be secured on the wound by means of an appropriate bandage. They have no suitable means with which the wound pad can be secured directly on the skin of the patient.
The present invention has therefore the object to provide an absorption body for placement onto wounds that has full absorption capacity but can be fixed also without further auxiliary means such as bandage material on the wound or on the skin of the patient.
Object of the present invention is an absorption body of the aforementioned kind that is characterized in that the layer A in the area of the wound has a material that is permeable for liquids and the layer B comprises breathable material.
The absorption body according to the invention is suitable in particular for placement onto wounds, i.e., onto so-called external wounds which generally may occur on the skin, including the mucous membrane, of the patient. These wounds can be acute injuries but also chronic wounds, i.e., wounds that do not heal or heal only by secondary wound healing, from which e.g. ichor exits.
A further object of the present invention is therefore the use of the absorption body as a wound pad.
The absorption body according to the invention has the advantage that the wound is covered by a layer that takes up the exuded bodily liquid, which layer takes up the exuded liquid or through which the liquid passes and is transported into the neighboring absorbent body or core in which the liquid is absorbed. The layer that is facing away from the skin has the advantage that it is breathable, i.e., permeable to water vapor but impermeable to larger molecules or particles. Perspiration can escape from the interior to the exterior of the absorption body placed on a wound. The wound that is covered by the absorption body according to the invention is not hermetically sealed; air and moisture exchange can take place, ichor and other liquids however cannot penetrate to the exterior and can also not pass from the exterior in the direction toward the wound. This has also the advantage that the breathable layer constitutes a barrier also for bacteria etc. which could infect the wound.
The absorption body according to the invention is a layered body of a multi-layer construction that is usually comprised substantially of a layer A that is facing the skin, a layer B that is facing away from the skin, and an absorbent body that is arranged between these two layers.
The layer A that is facing the skin is positioned immediately on the wound and on the skin surface surrounding the wound. In order to ensure an optimal wound care, the layer A, at least in the area in which it is resting immediately on the wound, is comprised of a liquid-permeable material. This liquid-permeable material can be selected from materials such as nonwoven or woven and/or perforated two-dimensional or three-dimensional films that preferably do not stick to wounds. Nonwoven materials are textile-like materials that are produced from long fibers and are connected to each other by means of chemical, mechanical, thermal or solvent treatment. They are thus textile flat structures of individual fibers and are liquid-permeable. In addition to the nonwovens (=fleece materials), also perforated or structured two-dimensional or three-dimensional films can be used as a layer A. As a two-dimensional configuration, the perforated films have holes in the surface that ensure that liquid can pass through the material. Perforated three-dimensional films are characterized in that by the perforations the perforated material extends across the plane of the flat structure so that a three-dimensional structure is produced. The three-dimensional structure reduces the contact surface area on the wound; this may further positively affect wound healing and prevents sticking of dried exudate. The materials from which the nonwoven materials or the perforated films are produced are preferably polyolefin films, such as polyethylene or polypropylene films or also nonwovens of natural material.
In a possible embodiment of the present invention, the layer A in the area outside of the wound can be provided at least partially with an adhesive. In this way, the absorption body can be secured or fixed on the body surface.
As adhesives all conceivable skin-compatible adhesives are conceivable as they are conventional and known in the production of adhesive plasters. Preferably, the adhesive should be a permanently adhesive material that even after a single use, i.e., when already applied once onto the skin surface and removed, can still be reused. Also, the adhesive, after contacting water, should preferably not lose its adhesive power. A preferably employed adhesive is so-called underindexed polyurethane, i.e., a polyurethane with low isocyanate index. Underindexed polyurethanes are obtained by reaction of polyisocyanates with long-chain polyols that are preferably free of any short-chain proportions.
The topside of the absorption body according to the invention, i.e., the side that is facing away from the skin is formed by layer B. Between the layers A and B the absorbent body or core is arranged. The layers A and B as well as the absorbent body can have the same dimensions. In a possible embodiment the dimensions of the absorbent body are smaller than that of the layers A and B. In this embodiment the absorbent body is essentially enclosed by the layers A and B. Preferably, the layers A and B have the same dimensions and the absorbent body is smaller than these two layers A and B so that the layers A and B project past the absorbent body. At these projecting portions the layers A and B can be connected to each other. In order to connect individual layers to each other, they can be adhesively connected, welded, sealed or connected in other ways, depending on the material from which these layers are formed. In a possible embodiment the dimensions of one of the two layers A or B is greater than that of the other layer, the projecting edges can therefore be folded over about the edge of the smaller layer so that the edges can also be dosed.
An optimal wound care is possible in particular when the layer that is facing away from the skin is a layer of breathable materials. The materials from which the layers A and B are produced, can be the same or different from each other. According to the invention, the layer B is breathable, i.e., it is permeable for water vapor (perspiration) but not for liquids. The layer B can be, for example, a breathable film such as a perforated two-dimensional and/or three-dimensional film, a breathable SMS (spunbond/meltblown/spunbond), nonwoven (fleeces) of natural or synthetic fibers, and/or a laminate of different materials, such as nonwoven and breathable film (BTBS films=breathable film textile backsheet), as they are conventionally used for producing external sides of incontinence products.
As a third layer, the absorption body according to the invention has an absorbent core. It is arranged between the layers A and B, preferably enclosed in the manner of an envelope by the layers A and B. The absorbent core serves for absorbing the exudates that are exiting from the wound and to absorb them permanently. A re-wetting in the direction of the wound should be prevented as much as possible. The absorbent core is therefore preferably formed of a material that is capable not only of absorbing bodily liquids but also of storing them, such as pulp or pulp-related materials as well as synthetic absorbent materials. The absorbent core is preferably a nonwoven of pulp fibers such as an airlaid.
In a preferred embodiment an absorbent core is used that is produced in accordance with the method described in European patent 1 032 342. Preferably, an airlaid of pulp fibers is used as absorbent material. In a preferred embodiment of the present invention, the absorbent core has, distributed across its surface, embossed areas in which the fibers, preferably pulp fibers, are more strongly compressed with each other than in other areas and, in this way, are connected to each other without adhesive and/or binding agent. In such an embodiment, the absorbent body is produced of a fiber material web of pulp fibers which, with formation of an embossed pattern in the compressed areas, are calendered and connected without binding agent in a spot-shaped or line-shaped pattern.
The absorbent core can have the embossed areas (be provided with the embossed areas) on the surface that is facing the layer A and/or the layer B. The fiber layer of the absorbent core is thus structured such that the pulp fibers outside of these discrete embossed areas are present in loosely placed form or only weakly adhering to each other, while in the embossed areas they are compressed with each other and are in intimate connection with the neighboring pulp fibers. With this embodiment, the use of adhesives and binding agents is completely unnecessary for formation of the composite of pulp fibers; this enables simple and complete recycling. In the embossed areas the fibers do not simply adhere to each other. Instead, because of pressure loading in the embossed areas, it is achieved that neighboring pulp fibers in these embossed areas are fixedly connected to each other. This connection is capable of resisting the action of moisture so that the absorption body according to the invention is distinguished by mechanical load capacity even in the wet state.
The areas outside of the discrete embossed areas, in which embossed areas the fibers are present in loosely laid form on top of each other or in a form where they only weakly adhere to each other, are characterized by an excellent absorption capacity. The absorbed liquid is absorbed by the fibers and is distributed across the entire surface area of the absorbent core and held therein.
In order to further increase the absorption capacity of the absorbent core, the absorbent core may contain particles of superabsorbent polymers (SAPs). They can be, for example, directly worked in during manufacture of the absorbent core.
The absorbent body C is arranged between the layers A and B and preferably enveloped by the layers A and B in the manner of an envelope. The absorbent body can be secured on one or both of the layers A and B or can be loosely enveloped by layers A and B. In order to avoid as much as possible sliding of the absorbent body within this envelope and to ensure that the absorbent body at least completely or partially covers the layer A at the location where it is resting on the wound, the absorbent body should have at least the same size as the wound. In a preferred embodiment, the absorbent body is smaller than the layer A.
The layers A and B are preferably closed at their outer edges. In a possible embodiment of the present invention the layers A and B are identical or almost identical and the edges are adhesively connected, welded or sealed to each other. This connection of the two layers can be realized immediately at the edges of the layers but also at a certain spacing away from the edges so that essentially a circumferentially extending seam is formed. An adhesive connection extending up to the adhesive core is also conceivable.
In a further possible embodiment of the present invention, the surface of one of the two layers A and B is greater than the other; the projecting surfaces of the larger layer can be folded about the edges of the smaller layer so that an envelope is produced also that encloses the absorbent body.
In order to increase the stability of the absorption body according to the invention, in a preferred embodiment of the present invention the absorbent body of the layer C and the layer B that is facing away from the skin are adhesively connected to each other, i.e., preferably glued. Gluing of the layers B and C prevents sliding of the absorbent core or body within the absorption body or wound pad and also provides stability of the absorption body (e.g. wound pad) as such. A stable and resilient product is obtained that usually will not burst even under load. Moreover, the adhesive connection also has advantages with respect to manufacturing technology; while a circumferentially extending adhesive edge allows only for minimal manufacturing tolerances, the manufacturing tolerances are significantly greater for partial or complete surficial adhesive connection.
The present invention will be explained in more detail with the aid of the attached figures.
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The layer 10 that determines the absorption behavior for liquids, in particular ichor, is comprised preferably of pulp fibers 11. The pulp fibers 11 are compressed in the embossed areas 12 and are connected to each other in this way. In the embodiment illustrated here, the embossed areas 12 are located opposite each other on the top side and bottom side so that in the respective embossed area 12 only a narrow stay of interconnected pulp material remains. The other areas of the layer 10 arranged between these embossed areas 12 have a loosely laid pulp layer. An intimate connection between the pulp fibers 11 does not exist in these areas.
The embossed areas 12 have in the embodiment illustrated here the shape of truncated pyramids or truncated cones, wherein the angle of the thus formed slanted sides should be between 10° and 45°.
As cellulose material for the layer 10 inexpensively available mass-produced material can be used. Preferably, if possible, unbleached so-called “fluff pulp” is used that, in contrast to bleached pulp materials, is characterized by an excellent binding behavior; this improves mechanical strength of the absorbent body with regard to vertical tensile forces.
When manufactured in a continuous method, the fiber material web that later on forms the layer 10 is manufactured of a layered arrangement of pulp fibers of defiberized pulp (wood pulp) loosely laid in an air stream and optionally interspersed absorbent materials. The fiber material web of pulp fibers is obtained by layered laying of the pulp fibers. When further absorbent materials, such as SAP (superabsorbent polymers), are added, this material addition can be done also by layered laying, for example, by alternatingly laying pulp fibers, absorbent material, pulp fibers until the desired quantity of pulp fibers and optionally absorbent material has been supplied. In the embodiment of an absorbent body, illustrated in
The tissue material is known in the prior art and can be obtained commercially as web material. The tissue material imparts additional stability to the absorbent body 6; it can also prevent that fine wear debris of the pulp fibers and/or of the absorbent materials can penetrate in the direction toward the wound through the layer A that is permeable for liquids.
For manufacturing a standardized defiberized product, it is possible to use commercially available renewable wood resources.
The method for layering pulp as a starting material for the layer 10 enables dry processing of the pulp fibers 11 and thus an excellent fusion of the pulp fibers in the discrete embossed areas by means of the subsequent embossment process between two structured rollers. Outside of the embossed areas 12 the fibers are loosely resting on each other; this improves the absorption capacity and flexibility of the layer 10.
The absorption behavior of the layer 10 is substantially “dry”, i.e. as long as a complete saturation has not been reached, the absorbed liquid cannot be squeezed out as it is possible with a sponge. Even after use and as long as the absorption behavior of the absorbent body 6 has not been exhausted, the absorption body therefore appears dry.
Manufacture is done on the basis of web material which is produced in a continuous process. In air-supported laying (air laying), first the pulp fibers and the SAPs for forming the layer 10 are laid. Subsequently, in a calandar with two structured calandar rollers the production of the embossed areas 12 is realized. In further continuous steps the top layer 3 above and the bottom layer 2 below are arranged and adhesively connected with the core layer 10. The thus produced web material is subsequently cut into individual, preferably rectangular, fields that are supplied in a further manufacturing step for producing the absorption body according to the invention.
The specification incorporates by reference the entire disclosure of German priority document 20 2010 008 025.8 having a filing date of Jul. 9, 2010.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2010 008 025.8 | Jul 2010 | DE | national |
