Wound dressing

Abstract

The invention relates to a wound dressing, which comprises a needle-punched non-woven fabric, and the needle-punched non-woven fabric contains superabsorbent fibers accounting for 30-80 wt% of the total weight of the needle-punched non-woven fabric; the weight of the self-crimped fibers accounts for 70 wt%-20 wt% of the total weight of the needle-punched non-woven fabric.

Description

Field of the Invention

[0001] The present invention relates to a wound dressing comprising a needle-punched nonwoven fabric containing superabsorbent fibers, and a method for manufacturing the wound dressing. The present invention also relates to the use of the needle-punched nonwoven fabric containing superabsorbent fibers in manufacturing wound dressings. Background Art

[0002] Highly absorbent nonwovens containing superabsorbent fibers are well known. They are often used as a component in wound dressings because of their strong absorption and retention capabilities for wound fluid. In addition, the high absorbent nonwovens have textile properties and adaptability, which helps to enhance the comfort of wound dressings.

[0003] However, nonwovens of this type containing superabsorbent fibers have the disadvantage that they do not expand reversibly, i.e. they do not or only barely react elastically to tensile forces. As a result, forces caused by, for example, the patient's movements can cause the wound dressing to fall off or slip. This is particularly true when the wound dressing is used on or around joints. Furthermore, if the components of the wound dressing have different elasticities, this can cause the components to delaminate.

[0004] Another disadvantage of nonwovens containing superabsorbent fibers is that they shrink when in contact with moisture from the air during storage and when they absorb liquids during use. If such nonwovens are used as a component of a wound dressing containing other non-shrinking layers, the shrinkage of the nonwoven can cause wrinkles or deformation of the entire wound dressing.

[0005] Furthermore, especially in the case of superabsorbent fibers consisting of polyacrylates or polymethacrylates, the superabsorbent fibers generally lose their integrity when absorbing aqueous liquids and the hydrogel formed in the process is unstable and cannot withstand mechanical influences in the nonwoven. Even the slightest mechanical stress can cause the gel particles to detach from the nonwoven.

[0006] Various methods have been proposed to impart elastic properties to the absorbent component of a wound dressing. However, these methods generally require the use of elastomeric materials or employ expensive manufacturing methods. In addition, some of these methods can only achieve elasticity in one dimension. For example, WO 2010 / 035017 A1 describes thread reinforcement with elastic yarns. However, this only achieves elasticity in the longitudinal direction. EP 3 666 295 A1 describes the joining of an absorbent nonwoven with a sheet made of an elastomeric material. This is relatively complex and the elasticity achieved is not uniform over the thickness of the resulting material.

[0007] EP3285705B1 describes a wound dressing with a fibrous layer which has a plurality of cutouts and is thus highly flexible. However, the elastic recovery capability of the deformable layer produced in this way is poor.

[0008] In addition, elastic nonwoven fabrics made of latent self-curling fibers have been disclosed. For example, US5454142A describes a method for producing nonwoven fabrics from fibers with mechanical curling and latent curling (self-curling). The nonwoven fabric is heated to form latent curling. The nonwoven fabric produced in this way has excellent elastomeric and foam-like compression and elastic properties. These fibers are made of thermoplastic materials, especially polyester, and have no or only very low absorption properties. Therefore, they are not suitable for use as components with absorption capacity in wound dressings. Summary of the invention

[0009] The object of the present invention is to provide a wound dressing which combines high elasticity with good absorption capacity, is mechanically stable after absorbing liquid, shrinks only minimally or not during storage in contact with liquid or moisture in the air, and has gel barrier properties. Another object of the present invention is to provide a method for producing a wound dressing and the use of a nonwoven fabric in the production of a wound dressing.

[0010] The solution of the present invention to achieve the above-mentioned object is a wound dressing, comprising a needle-punched nonwoven fabric, wherein the needle-punched nonwoven fabric contains:

[0011] - 30 wt % to 80 wt %, preferably 40 wt % to 75 wt %, more preferably 45 wt % to 70 wt %, in particular 55 wt % to 65 wt % of superabsorbent fibers relative to the total weight of the needle-punched nonwoven fabric;

[0012] 70 to 20 wt%, preferably 60 to 25 wt%, more preferably 55 to 30 wt%, in particular 45 to 35 wt% of self-crimped fibers relative to the total weight of the needle-punched nonwoven fabric.

[0013] The wound dressing of the present invention is characterized by high elasticity and good absorption capacity. At the same time, the wound dressing is mechanically stable, does not shrink or shrinks very little after absorbing liquid or when in contact with moisture in the air during storage, and has gel barrier properties.

[0014] Without being bound by mechanism, it is speculated that the reason for these favorable properties is that the self-crimping fibers are able to incorporate the superabsorbent fibers well into their framework structure and thus stabilize them. As a result, the gel formed by the superabsorbent fibers when absorbing aqueous liquids is integrated with the needle-punched nonwoven in a stable manner to resist mechanical influences. It is very surprising that only a very small proportion of self-crimping fibers can achieve good incorporation of gel while elastic recovery. It has also been found that the wound dressing of the present invention has gel barrier properties. This is beneficial in terms of wound dressings because it prevents liquid from flowing vertically out of the wound edge, which reduces the contact of uninjured skin with liquid and prevents maceration. It is speculated that the reason for this effect is that the self-crimping fibers cause the needle-punched nonwoven to be compacted, resulting in a reduction in the free volume available for liquid transport. Self-crimping fibers refer to fibers made of self-crimping fibers (also called latent self-crimping fibers). The curling properties of such fibers can be activated by heat treatment to activate their latent curling ability. Preferably, the needle-punched nonwoven is heat-treated. The advantage of using self-crimping fibers is that they impart a higher elasticity to the needle-punched nonwoven.

[0015] Preferably, the self-curling fiber has a fiber material selected from the following material group: polyamide, such as polyamide 6, polyamide 6,6 or polyamide 11; polyester, such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polybutylene succinate (PBS); polyolefin, such as polypropylene (PP) or polyethylene (PE), or a mixture or copolymer thereof.

[0016] Preferably, the self-crimping fiber is a fiber made of self-crimping fibers (also called latent crimping fibers) comprising at least two components, wherein the shrinkage characteristics of one component under heat treatment are different from those of the other component, and wherein the arrangement of the components causes three-dimensional deformation of the fiber, such as a vortex line or a spiral line, or an irregular structure different from a straight line.

[0017] Also preferably, the self-crimping fibers are made of self-crimping fibers, wherein at least one fiber component has different shrinkage characteristics under heat treatment than at least one additional fiber component. This difference is achieved by using different polymers that differ in morphology. For example, a homopolymer can be used as one component and a copolymer as the other component. Alternatively, the morphological differences can be produced by different molecular weights, stereochemical structures, branching or crosslinking degrees. Self-crimping fibers generally have a first fiber component and a second fiber component.

[0018] Preferably, the fiber components of the self-crimping fiber, in particular the first fiber component and the second fiber component, have fiber materials, which are independently selected from the following material groups: polyamides, such as polyamide 6, polyamide 6,6 or polyamide 11; polyesters, such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polybutylene succinate (PBS); polyolefins, such as polypropylene (PP) or polyethylene (PE), or mixtures or copolymers thereof.

[0019] The self-crimping fibers and / or the self-crimping fibers used as starting materials can be present as bicomponent fibers, wherein the fiber components are arranged side by side, for example, with an overall circular cross section, or with an eccentric core / sheath arrangement with an overall circular cross section. However, the crimping potential can also be achieved by other cross sections and bicomponent forms disclosed in the prior art.

[0020] As mentioned above, the self-crimping fiber used in the present invention is made of self-crimping fiber, and its curling can be obtained by thermally triggering its latent curling ability. The advantage of this is that the curling is implemented after the nonwoven fabric is made, so that elastic recovery can be formed and good inclusion of superabsorbent fiber can be ensured at the same time.

[0021] The self-crimping fiber may have mechanical crimp regardless of its self-crimping. Preferably, the fiber is given mechanical crimp using a stuffing box or a saw wheel during the fiber manufacturing process. Such mechanical crimping can improve the processability of the potential self-crimping fiber during the nonwoven fabric manufacturing process.

[0022] In the present invention, preferably, the self-crimping fibers and the super absorbent fibers are both short fibers. This is advantageous because a needle-punched nonwoven fabric with a larger volume can be produced, which helps to give the needle-punched nonwoven fabric absorption properties. The short fiber lengths of the self-crimping fibers and / or the super absorbent fibers are independent of each other and are preferably 32 mm to 80 mm, preferably 38 mm to 70 mm, and particularly preferably 40 mm to 60 mm. The fineness of the self-crimping fibers and / or the super absorbent fibers is independent of each other and is preferably 1.7 dtex to 20 dtex, particularly preferably 2.0 dtex to 10 dtex.

[0023] Superabsorbent fibers refer to fibers formed from materials having the property of absorbing aqueous liquids to form hydrogels. Preferred superabsorbent fibers have a free absorption capacity for NaCl aqueous solution (0.9 wt%) of at least 20 g / g, such as 20 g / g to 70 g / g, preferably at least 30 g / g to 60 g / g, particularly preferably 40 g / g to 50 g / g, see the definition in the measurement method paragraph.

[0024] Preferred superabsorbent fibers contain a polymer selected from the group consisting of polyacrylic acid and / or polymethacrylic acid, unsaturated carboxylic acid graft copolymers, modified cellulose, gel-forming polysaccharides other than modified cellulose, and mixtures thereof.

[0025] Preferred polyacrylic acid and / or polymethacrylic acid are selected from acrylic acid polymers, methacrylic acid polymers, acrylic acid / methacrylic acid copolymers and mixtures thereof. The acid groups of the polymer gel are preferably partially neutralized to form sodium salts. Also preferably, crosslinks are present between polymer chains. Superabsorbent fibers that can be used in the present invention are commercially available products under the trade name OASIS SAF, manufactured by TECHNICAL ABSORBENTS LTD.

[0026] In another preferred embodiment, the superabsorbent fiber, in particular the superabsorbent fiber containing polyacrylate, has a double-layer structure, which has an outer superabsorbent layer with carboxyl groups by hydrolysis treatment and an inner layer composed of polyacrylonitrile. Such fibers are described in US4366206A, the trade name is LANSEAL, manufactured by JAPAN EXLAN CO., LTD.

[0027] Likewise suitable are superabsorbent fibers having compounds consisting of copolymers of unsaturated carboxylic acids with disaccharides, oligosaccharides and / or polysaccharides. Such fibers are described, for example, in US Pat. No. 4,788,237 A.

[0028] Preferred unsaturated carboxylic acid graft copolymers are copolymers of unsaturated carboxylic acid and disaccharides, oligosaccharides and / or polysaccharides.

[0029] Likewise preferred superabsorbent fibers are made by chemical modification of cellulose fibers. Preferred cellulose fibers are carboxymethylated cellulose fibers, in particular cellulose fibers as described in EP0680344. Also preferred cellulose fibers are carboxyethylated cellulose fibers, in particular cellulose fibers as described in WO2011022740A1. Also preferred cellulose fibers are fibers obtained by alkylsulfonation of cellulose fibers, in particular fibers as described in EP2196224A1.

[0030] Preferred modified celluloses are selected from the group consisting of carboxymethylated cellulose, carboxyethylated cellulose, alkylsulfonated cellulose and mixtures thereof.

[0031] Likewise suitable superabsorbent fibers contain polymers selected from gel-forming polysaccharides, in particular selected from alginates, pectins, chitosans or hyaluronic acid and mixtures thereof. Particularly preferred superabsorbent fibers of this type are described in EP 1 085 912 A1.

[0032] In addition to superabsorbent fibers and self-crimping fibers, the needle-punched nonwoven fabric may also contain other fibers, preferably fibers selected from one or more of the following fiber raw materials: polyolefins, cellulose, regenerated cellulose, in particular viscose, polyamide, polyacrylonitrile, spandex, polyvinyl chloride, polylactic acid, polyglycolide, polyesteramide, polycaprolactone, polyhexamethylene terephthalate, polyhydroxybutyrate, polyhydroxyvalerate, animal and / or plant natural fibers and / or polyester.

[0033] Preferred additional fibers are hydrophilic fibers. The term "hydrophilic fibers" in the present invention means that the relevant fibers have a fiber material on the surface, the surface energy of which is measured according to DIN 55660-2:2011-12> 35 mN / m. Particularly preferred hydrophilic fibers are selected from hydrophilic fibers containing one or more fiber raw materials, selected from cellulose, preferably regenerated cellulose, in particular viscose.

[0034] The advantage of hydrophilic fibers is that they can make the needle-punched nonwovens have excellent wettability even after heat treatment during use. This in turn facilitates vertical liquid transport.

[0035] If present, the proportion of other fibers is preferably 5 to 30 wt%, more preferably 10 to 20 wt%, relative to the total weight of the needle-punched nonwoven.

[0036] According to the present invention, the wound dressing comprises needle-punched nonwoven fabrics. Nonwoven fabrics refer to textile sheets formed and consolidated into a fiber web by fibers, filaments or cut yarns, using a process other than weaving, knitting or braiding.

[0037] The distinction between nonwovens and other textile sheets is defined in the standard DIN EN ISO 9092:2019-08. The fibers can be formed into a web by various processes such as carding, air-laying, wet-laying or melt-spinning. Carded webs are preferred. The web can be pre-consolidated to facilitate processing.

[0038] In a preferred embodiment of the present invention, the superabsorbent fibers and the self-curling fibers are preferably evenly distributed in the needle-punched nonwoven fabric. That is, the fibers are not arranged in the form of different layers in the nonwoven fabric. This even distribution can be achieved in a manner well known to those skilled in the art, for example by combing the fibers during the fiber web manufacturing process. The advantage of even distribution is that the superabsorbent fibers can be well incorporated into the frame structure of the self-curling fibers.

[0039] The nonwoven fabric of the present invention is a needle-punched nonwoven fabric. Needle-punched nonwoven fabric refers to a sheet formed by solidifying a fiber web by needle-punching. The needles used have a tip for producing a vertical puncture channel in the fiber web, and a notch for grabbing the fiber or fiber bundle and pulling it into the vertical puncture channel during the puncture movement. As a result, the needle-punched nonwoven fabric has areas with high fiber density and partially vertical orientation of the fibers, and areas with low fiber density located between the puncture channels. The advantage of the needle-punched nonwoven fabric is that the needle-punching provides an area to fix the needle-punched nonwoven fabric, and the fibers are gathered together between the fixed areas by curling. This can improve the elastic deformation capacity. Preferably, the needle-punching density of the needle-punched nonwoven fabric is 50 needles / cm 2 Up to 150 stitches / cm 2 , preferably 70 needles / cm 2 Up to 120 needles / cm 2 , especially 90 needles / cm 2 Up to 110 needles / cm 2 .

[0040] As mentioned above, the needle-punched nonwoven fabric is preferably heat-treated. This can trigger the latent crimping ability of the self-crimping fibers used as the starting material. The needle-punched nonwoven fabric is generally heat-treated at a temperature of 160°C to 200°C, preferably 180°C to 190°C.

[0041] In another preferred embodiment of the present invention, the wound dressing has at least one additional fiber layer, which is arranged on at least one side of the needle-punched nonwoven. Preferably, the additional fiber layer is connected to the needle-punched nonwoven by needle-punching. This is advantageous because the fixation by needle-punching forms puncture channels, which accelerate the transfer of liquid from the additional fiber layer to the needle-punched nonwoven. Preferably, the additional fiber layer is constructed as a nonwoven.

[0042] Particularly preferably, the at least one additional fiber layer is connected to the needle-punched nonwoven in that the at least one additional fiber layer is superimposed on a fiber web serving as starting material for the production of the needle-punched nonwoven and these fiber webs are needle-punched together.

[0043] If present, the at least one additional fiber layer is configured to be hydrophilic in one embodiment. The term “configured to be hydrophilic” in the context of the present invention means that the fiber layer has a surface energy of greater than 35 mN / m (measured in accordance with DIN 55660-2:2011-12).

[0044] This is advantageous since such a fiber layer absorbs the liquid very quickly and transfers it into the interior of the nonwoven.

[0045] In another embodiment, the at least one additional fiber layer is designed to be hydrophobic. The term "hydrophobic fiber layer" in the present invention means that the fiber layer has a surface energy of less than 35 mN / m (measured according to DIN 55660-2:2011-12). This is advantageous because direct contact of such a fiber layer with the wound does not cause the wound dressing to stick to the wound.

[0046] In another preferred embodiment, the at least one additional fiber layer is thermoplastic. This is advantageous because such a fiber layer can be flattened so that loose fiber ends can be embedded therein. This is also advantageous because such a fiber layer can be thermally laminated with other conventional components of a wound dressing.

[0047] In another preferred embodiment, the at least one additional fiber layer is designed as a thermoplastic elastomer. This is advantageous because the use of such a fiber layer promotes the thermoplastic and elastic properties of the wound dressing.

[0048] In another preferred embodiment, the at least one additional fibrous layer comprises fibers with hydrophilic properties and fibers that exhibit thermoplastic properties at a temperature that causes curling of the self-crimping fibers. This is advantageous because a fibrous layer with this construction is able to transport and distribute aqueous liquid on the surface before it is absorbed by the layer containing superabsorbent fibers. This is advantageous for rapidly absorbing large amounts of wound exudate.

[0049] In another preferred embodiment of the present invention, the wound dressing, in particular the needle-punched nonwoven fabric, contains at least one antimicrobial active ingredient selected from, for example, silver, silver salts (such as silver nitrate or silver sulfate), iodine-containing compounds, biguanides (such as chlorhexidine or polyhexamethylene biguanide ("PHMB")), quaternary ammonium compounds (such as benzalkonium chloride) or octenidine hydrochloride and mixtures thereof. If provided, the wound dressing, in particular the needle-punched nonwoven fabric, has an antimicrobial active ingredient content of 0.1 g to 10 g per square meter, preferably 0.5 g to 5 g per square meter.

[0050] The wound dressing, in particular the needle-punched nonwoven, may also have a variety of additives. Preferred additives are selected from pharmacologically active ingredients or drugs, in particular analgesics, anti-inflammatory agents, wound healing promoters, hemostatic agents, enzymes, amino acids, antioxidants, peptides, peptide sequences, polysaccharides, in particular chitosan, growth factors, in particular purines, pyrimidines, odor adsorbing additives, in particular activated carbon and / or processing aids, in particular surfactants, wetting agents, brighteners, antistatic agents and / or mixtures thereof.

[0051] If provided, the wound dressing, in particular the needle-punched nonwoven, contains other additives in an amount of 0.1 g to 10 g per square meter, preferably 0.5 g to 5 g per square meter.

[0052] The wound dressing may also contain other common components, such as a hydrophilic foam (eg, polyurethane foam), a liquid-impermeable backing layer, and / or an adhesive.

[0053] The wound dressing and / or the needle punched nonwoven fabric of the present invention is characterized by minimal shrinkage when in contact with liquid or moisture in the air during storage. Preferably in the present invention, the wound dressing and / or the needle punched nonwoven fabric shrinks by 0% to 10%, more preferably by 0% to 5%, after 24 hours of contact, as measured as defined in the measurement method paragraph.

[0054] Another feature of the wound dressing and / or needle-punched nonwoven fabric of the present invention is high absorption rate. In the present invention, preferably, the wound dressing and / or the needle-punched nonwoven fabric has an absorption capacity of 1000% to 5000%, or 1000% to 2500% for a 0.9% sodium chloride aqueous solution, as measured as defined in the measurement method paragraph.

[0055] The wound dressing and / or the needle-punched nonwoven according to the invention is characterized by a high elasticity. Preferably, the wound dressing and / or the needle-punched nonwoven has a plastic deformation ratio ε(pl) in the longitudinal direction and / or in the transverse direction, particularly preferably in the longitudinal direction and in the transverse direction, of less than 12%, preferably less than 10%, particularly preferably less than 8%, as determined as defined in the measurement method section.

[0056] Another feature of the wound dressing and / or needle-punched nonwoven according to the invention is good gel barrier properties, which is reflected in a low rise height of the NaCl solution. Preferably, the wound dressing and / or needle-punched nonwoven according to the invention has a rise height of less than 30 mm, preferably less than 20 mm, of a 0.9 wt. % NaCl solution in the longitudinal direction and / or in the transverse direction, preferably in the longitudinal direction and in the transverse direction, as determined as defined in the measurement methods section.

[0057] Further preferably, the wound dressing and / or the needle-punched nonwoven fabric of the present invention is sterile. That is, the wound dressing and / or the needle-punched nonwoven fabric is preferably sterilized by standard sterilization methods. Advantageously, the wound dressing is sterilized by at least one of the following methods: high-energy radiation, in particular gamma radiation, heating under pressure, in particular using steam in an autoclave, or reactive chemicals (such as ethylene oxide).

[0058] Further preferably, the wound dressing and / or the needle-punched nonwoven fabric of the present invention is formed by calendering.

[0059] The wound dressing of the present invention can advantageously be manufactured by a method comprising the steps of:

[0060] 1) manufacturing and / or providing a fiber web, the fiber web containing 30 wt% to 80 wt%, preferably 40 wt% to 75 wt%, more preferably 45 wt% to 70 wt%, especially 55 wt% to 65 wt% of superabsorbent fibers relative to the total weight of the fiber web, and 70 wt% to 20 wt%, preferably 60 wt% to 25 wt%, more preferably 55 wt% to 30 wt%, especially 45 wt% to 35 wt% of self-crimping fibers relative to the total weight of the fiber web;

[0061] 2) reinforcing the fiber web obtained in step 1) into a needle-punched nonwoven fabric by needle-punching;

[0062] 3) Inducing the self-crimping fibers of the reinforced fiber web obtained in step 2) to self-crimp, preferably by heat treatment, wherein a wound dressing is obtained.

[0063] The method steps are preferably carried out sequentially.

[0064] Preferred embodiments of the method of the invention encompass the preferred embodiments described for the wound dressing of the invention.

[0065] Preferably, in step 1), the fiber web is produced in such a way that the fiber types are evenly distributed. This can be achieved, for example, by carding. A carded fiber web is thus preferably provided.

[0066] In a further preferred embodiment, the fiber web is laid using a cross-plyer.

[0067] In the case of using more fibers, it is preferred that the fibers are uniformly mixed with the superabsorbent fibers and the self-crimping fibers when manufacturing the fiber web.

[0068] The self-crimping fibers are used as starting materials for the manufacture of needle-punched nonwoven fabrics. The self-crimping fibers may have mechanical crimps regardless of their self-crimping properties. Preferably, the mechanical crimps are formed during the manufacture of the fibers, usually using a stuffing box or a sawtooth. Such mechanical crimps are advantageous because they can improve the processability of the self-crimping fibers.

[0069] In step 2), the fiber web obtained in step 1) is reinforced into a needle-punched nonwoven fabric by needle-punching. Preferably, the needle-punched nonwoven fabric is punched at 50 needles / cm 2 Up to 150 stitches / cm 2 , preferably 70 needles / cm 2 Up to 120 needles / cm 2 , especially 90 needles / cm 2 Up to 110 needles / cm 2 Acupuncture was performed.

[0070] In step 3), the self-crimping fibers of the reinforced fiber web obtained in step 2) are preferably induced to self-crimp by heat treatment, generally at a temperature of 160°C to 200°C, preferably 180°C to 190°C.

[0071] Preferably, the self-crimping of the self-crimping fibers is achieved by processing the needle-punched nonwoven material in a single-pass dryer equipped with a conveyor belt and dragging the conveyor belt. This is advantageous because the needle-punched nonwoven fabric produced in this way has uniform elasticity in the longitudinal and transverse directions.

[0072] In another preferred embodiment, the self-crimping of the self-crimping fibers is induced by treating the needle-punched nonwoven in a continuous dryer with a tenter frame. Preferably, the width of the clamped material is reduced by closing the tenter frame during the treatment. This is advantageous because the needle-punched nonwoven produced in this way has selective elasticity in the transverse direction. This increases the processing capacity of the wound dressing equipment.

[0073] In another preferred embodiment, the self-curling of the self-curling fibers is induced by treating the needle-punched nonwoven in a continuous dryer with a tenter frame, wherein the width of the clamped material is reduced by closing the tenter frame during the treatment process, and at the same time, the distance between the fixing points of the needle-punched nonwoven on the tenter frame is reduced by closing the fixing elements of the tenter frame in the machine running direction.

[0074] This is advantageous because the needle-punched nonwovens produced in this way have varying degrees of elasticity in the longitudinal and transverse directions.

[0075] Furthermore, individual components of the method, in particular the wound dressing and / or the needle-punched nonwoven, can be finished and / or post-treated.

[0076] A preferred post-treatment comprises applying a wetting agent. Advantageously, the wetting agent is applied to the wound dressing and / or the needle-punched nonwoven.

[0077] Another preferred post-treatment includes sterilization. Advantageously, the wound dressing and / or the needle-punched nonwoven is sterilized, in particular by at least one of the following methods: high-energy radiation, in particular gamma radiation, heating under pressure, in particular using steam in an autoclave, or reactive chemicals such as ethylene oxide.

[0078] Another preferred post-treatment comprises calendering. The wound dressing and / or the needle-punched nonwoven is preferably calendered. The calendering is preferably performed with at least one calendering roller with a structured surface. This is advantageous because a further fixing effect can be achieved and / or a structured surface can be provided.

[0079] Likewise possible post-treatments are preferably post-curing, coating and / or chemical finishing of the wound dressing and / or the needle-punched nonwoven.

[0080] A similarly feasible post-treatment is the provision of processing aids and / or additives. In the case of the heat treatment in step 3), the post-treatment is preferably carried out after the heat treatment is complete. For example, brighteners, antistatic agents, surfactants, stabilizers and / or release agents can be used as processing aids.

[0081] Another subject of the invention is the use of a needle-punched nonwoven for producing a wound dressing, the needle-punched nonwoven comprising:

[0082] - 30 wt % to 80 wt %, preferably 40 wt % to 75 wt %, more preferably 45 wt % to 70 wt %, in particular 55 wt % to 65 wt % of superabsorbent fibers relative to the total weight of the needle-punched nonwoven;

[0083] 70 to 20 wt%, preferably 60 to 25 wt%, more preferably 55 to 30 wt%, in particular 45 to 35 wt% of self-crimped fibers relative to the total weight of the needle-punched nonwoven fabric.

[0084] Preferred embodiments of the use of the invention include mutatis mutandis the preferred embodiments described for the wound dressing of the invention.

[0085] The present invention is described in detail below with reference to a number of non-limiting examples.

[0086] Example 1

[0087] On a carding machine with a cross-plyer, three cardings with a unit area weight of 150 g / m 2 Fiber webs in which the superabsorbent fibers (Oasis 112) and latent self-crimping fibers were mixed in different proportions (Examples 1 to 3), and another fiber web consisting only of latent self-crimping polyester fibers (Comparative Example 1). The fiber webs were needle-punched using a needle-punching chair (Nadelstuhl) equipped with R222 G needles produced by Groz-Beckert, with a needle-punching depth of 10 mm and a needle-punching rate of 100 needles / cm 2 The needle-punched nonwoven obtained in the above manner was passed through a continuous dryer at 185° C. with a 5% advance, so that the material could shrink freely by triggering the latent transverse self-curling.

[0088] The reference sample with superabsorbent fibers is a needle-punched nonwoven fabric composed of 60 wt % superabsorbent fibers (Oasis 112) and 40 wt % mechanically crimped polyester fibers without self-crimp (Comparative Example 2).

[0089] Super absorbent fiber Self-curling fibers Example 1 20wt% 80wt% Example 2 40wt% 60wt% Example 3 60wt% 40wt% Comparative Example 1 0wt% 100wt% Comparative Example 2 60wt% 0wt%

[0090] The elasticity and the absorption capacity of 0.9% sodium chloride solution of the needle-punched nonwoven fabric produced in this way were measured.

[0091]

[0092]

[0093] The results show that all the examples of the present invention have higher elastic recovery and higher NaCl solution absorption rate.

[0094] The shrinkage of the needle-punched nonwoven fabrics produced in Example 3 and Comparative Example 2 upon contact with moisture in the air was determined in the manner defined in the Measurement Methods section.

[0095] 2h 4h 6h 24h Example 3 0％ 1.8％ 2.0％ 3.3％ Comparative Example 2 2.0％ 6.0％ 8.7％ 11.3％

[0096] The results show that the shrinkage degree of Example 3 is much less than that of Comparative Example 2 containing the same ratio of superabsorbent fiber (Oasis 112).

[0097] Example 2

[0098] Another needle-punched nonwoven fabric was produced in the same manner as in Example 3, having 60 wt % of the superabsorbent fiber Lanseal FK.

[0099] Super absorbent fiber Self-curling fibers Example 4 60% Lanseal 40％

[0100] The rising heights of the NaCl solutions in Example 3, Example 4 and Comparative Example 2 along the longitudinal and transverse directions were measured.

[0101]

[0102] The results show that the rising heights of Examples 3 and 4 are much smaller than that of Comparative Example 2 containing the same proportion of superabsorbent fibers (Oasis 112).

[0103] Example 3

[0104] The gel formed from the superabsorbent fibers in Example 3 and Comparative Example 2 was compared with respect to its fusion properties. For this purpose, a 10×10 cm test piece was punched out, placed in deionized water for 5 minutes, and then a weight of 4100 kg with a bottom area of ​​10 cm×10 cm was applied to the grid for 5 minutes, and then it was placed on an adhesive tape (CMC 10966 polyester tape from the manufacturer CMC Klebetechnik) and pressed twice with a roller weighing 1580 kg. Finally, the test piece was removed from the adhesive tape. The gel that flowed out of the gel-like needle-punched nonwoven was manually evaluated and the appearance of the test piece was compared.

[0105] The visible gel flowing out from the surface in Example 3 is much less than that in Comparative Example 2. Figure 2 As shown, in Example 3, the shape is better maintained after being removed from the tape (A1: Example 3 before testing; A2: Example 3 after testing; B1: Comparative Example 2 before testing; B2: Comparative Example 2 after testing).

[0106] Measurement method

[0107] Free absorbent capacity of the fiber:

[0108] 1 g of superabsorbent fiber sample (W1) was weighed and placed in a tea bag (acrylic / polyester fine mesh gauze), which was immersed in excess 0.9 wt% NaCl solution (adjusted to 20°C) for one hour. Excess solution was then removed by hanging the bag until no more liquid dripped. The tea bag was weighed (W2). The process was repeated with an empty tea bag and weighed (W0), and the swelling capacity was calculated according to the following formula:

[0109] Free absorption capacity = (W2-W1-W0) / W1.

[0110] Shrinkage on contact with moisture in the air:

[0111] The degree of shrinkage is determined by punching out workpieces of wound dressing and / or nonwoven with a size of 10.0 cm x 10.0 cm (area 1) and storing them in an air-conditioned cabinet at a temperature of 37° C. and a relative air humidity of 45%. After a specified time, the punched and stored workpieces are removed from the air-conditioned cabinet and the workpiece dimensions (area 2) are measured. The degree of shrinkage of the punched workpiece can then be calculated according to the following formula:

[0112]

[0113] Absorption capacity:

[0114] The absorption capacity is determined by punching out and weighing a workpiece of 10.0 cm x 10.0 cm made of wound dressing and / or nonwoven (weight 1) and immersing it in a 0.9 wt % sodium chloride solution (temperature adjusted to 20° C.). The punched and immersed workpiece is removed from the solution and allowed to drip for 2 minutes. It is then weighed again (weight 2). The absorption capacity is calculated according to the following formula:

[0115]

[0116] elasticity:

[0117] To characterize the elasticity, a 50 mm wide rectangular test body is punched out of the wound dressing and / or nonwoven and clamped in a tensile testing machine (e.g. Zwick / Roell Z020 / SN3A.02SO1) with a clamping length of 200 mm. The test body is stretched at a speed of 10 mm / min until a preload force F(vor) of 0.2 N is measured. The length at which F(vor) is reached is considered the starting length L(0). From this point on, further stretching is carried out at a constant speed of 100 mm / min to a distance of L(0)*120% and then back-pulled at 100 mm / min until the measured force has dropped back to 0.2 N. The corresponding distance relative to L(0) is considered the plastic deformation ratio ε(pl) in the stress-strain diagram. Wound dressings and / or nonwovens with greater elasticity are characterized by smaller ε(pl) values. All measurements are carried out 5 times and the results are averaged.

[0118] Figure 1 An exemplary stress-strain diagram is shown.

[0119] Height of NaCl solution

[0120] The height of rise of 0.9 wt% NaCl is determined according to DIN EN ISO 9073-06 using an instrument consisting of a tank, a vertical scale with 1 mm graduations and a clamp that can be adjusted in height relative to the tank. The plastic tank is filled with 0.9 wt% NaCl solution to the overflow height and the zero point of the scale is adjusted to the filling height of the NaCl solution.

[0121] A test body of 250 mm x 30 mm is punched out. Two holes are provided at one end of the test body and reinforced with a metal rod passing through the holes. The specimen is fixed in the clamp so that the end reinforced with the metal rod points downwards and hangs above the surface of the liquid.

[0122] When starting the measurement, lower the adjusting clamp so that the end reinforced with the metal rod is completely immersed in the liquid. After 5 minutes, read the height of the liquid front with the help of the dial. If the liquid front is uneven, read the highest point of the rising height.

Claims

1. A wound dressing, comprising a needle-punched nonwoven fabric, wherein the needle-punched nonwoven fabric contains: - 30 wt % to 80 wt % of superabsorbent fibers accounting for the total weight of the needle-punched nonwoven fabric; - 70 wt% to 20 wt% of self-crimped fibers accounting for the total weight of the needle-punched nonwoven fabric.

2. The wound dressing according to claim 1, characterized in that The needle-punched nonwoven fabric is heat-treated.

3. The wound dressing according to claim 1 or 2, characterized in that The self-crimping fiber has a fiber material selected from the following material group: polyamide, such as polyamide 6, polyamide 6,6 or polyamide 11; polyester, such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polybutylene succinate (PBS); polyolefin, such as polypropylene (PP) or polyethylene (PE), or a mixture or copolymer thereof.

4. The wound dressing according to any one or more of the preceding claims, characterized in that The self-crimping fibers are made of self-crimping fibers of at least two components, wherein the shrinkage characteristics of one component under heat treatment are different from those of the other component, and the arrangement of the components causes three-dimensional deformation of the fibers under heat treatment, and / or the self-crimping fibers are made of self-crimping fibers, wherein the shrinkage characteristics of at least one fiber component under heat treatment are different from those of at least one additional fiber component.

5. The wound dressing according to any one or more of the preceding claims, characterized in that The self-crimping fibers and / or the self-crimping fibers used as a starting material are present in the form of bicomponent fibers.

6. The wound dressing according to any one or more of the preceding claims, characterized in that The self-crimping fibers and the superabsorbent fibers are short fibers, wherein the short fiber lengths of the self-crimping fibers and / or the superabsorbent fibers are independent of each other and are preferably 32 mm to 80 mm, and / or the finenesses of the self-crimping fibers and / or the superabsorbent fibers are independent of each other and are preferably 1.7 dtex to 20 dtex.

7. The wound dressing according to any one or more of the preceding claims, characterized in that The superabsorbent fibers contain a polymer selected from the group consisting of unsaturated carboxylic acid polymers, unsaturated carboxylic acid graft copolymers, modified cellulose, gel-forming polysaccharides (excluding modified cellulose), and mixtures of these polymers.

8. The wound dressing according to any one or more of the preceding claims, characterized in that The needle-punched nonwoven fabric also contains other fibers, preferably one or more fibers selected from the following fiber raw materials: polyolefins, cellulose, regenerated cellulose, especially viscose, polyamide, polyacrylonitrile, spandex, polyvinyl chloride, polylactic acid, polyglycolide, polyesteramide, polycaprolactone, polyhexamethylene terephthalate, polyhydroxybutyrate, polyhydroxyvalerate, animal and / or plant natural fibers, and / or polyester.

9. The wound dressing according to claim 8, characterized in that The other fibers are hydrophilic fibers, preferably selected from one or more of the following fiber raw materials: cellulose, regenerated cellulose, in particular viscose.

10. The wound dressing according to claim 8 or 9, characterized in that Relative to the total weight of the needle-punched nonwoven fabric, the proportion of the other fibers is 5wt% to 30wt%, more preferably 10wt% to 20wt%.

11. The wound dressing according to any one or more of the preceding claims, characterized in that The needle-punched nonwoven fabric has a needle-punching density of 50 needles / cm 2 Up to 150 stitches / cm 2 , preferably 70 needles / cm 2 Up to 120 needles / cm 2 , especially 90 needles / cm 2 Up to 110 needles / cm 2 .

12. The wound dressing according to any one or more of the preceding claims, characterized in that The wound dressing comprises at least one additional fibrous layer, which is arranged on at least one side of the needle-punched nonwoven, wherein the at least one additional fibrous layer is preferably connected to the needle-punched nonwoven by needling.

13. The wound dressing according to claim 12, characterized in that The at least one additional fiber layer is designed to be hydrophilic.

14. The wound dressing according to any one or more of the preceding claims, characterized in that The shrinkage of the wound dressing and / or the needle-punched nonwoven after contact with moisture in the air for 24 hours is 0% to 10%, more preferably 0% to 5%, measured as defined in the measurement method section; and / or the absorption capacity of the needle-punched nonwoven for a 0.9% aqueous sodium chloride solution is 1000% to 5000%, or 1000% to 2500%, measured as defined in the measurement method section; and / or the plastic deformation ratio ε(pl) of the wound dressing and / or the needle-punched nonwoven in the longitudinal direction and / or in the transverse direction, in particular preferably in the longitudinal direction and in the transverse direction, is less than 12%, preferably less than 10%, particularly preferably less than 8%, measured as defined in the measurement method section; and / or the rise height of a 0.9 wt % NaCl solution of the wound dressing and / or the needle-punched nonwoven in the longitudinal direction and / or in the transverse direction, preferably in the longitudinal direction and in the transverse direction, is less than 30 mm, preferably less than 20 mm.

15. A method of manufacturing a wound dressing, comprising the steps of: 1) manufacturing and / or providing a fiber web, wherein the fiber web contains 30 wt% to 80 wt% of superabsorbent fibers accounting for the total weight of the fiber web, and 70 wt% to 20 wt% of self-crimping fibers accounting for the total weight of the fiber web; 2) reinforcing the fiber web obtained in step 1) into a needle-punched nonwoven fabric by needle-punching; 3) Preferably, heat treatment is performed to make the self-crimping fibers in the reinforced fiber web obtained in step 2) self-crimp, thereby obtaining a wound dressing.

16. Use of a needle-punched nonwoven fabric for manufacturing a wound dressing, the needle-punched nonwoven fabric comprising: - 30 wt % to 80 wt % of superabsorbent fibers accounting for the total weight of the needle-punched nonwoven fabric; - 70 wt% to 20 wt% of self-crimped fibers accounting for the total weight of the needle-punched nonwoven fabric.

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