JP2002065722A - Wound coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wound coating material which is capable of absorbing a considerable amount of the exudate exudated from a wound surface, is capable of prolonging the effective life of the covering material by evaporating the moisture included in the exudate into the surrounding environment by transferring this moisture to the outside surface of the coating material through the wound coating material within a prescribed rate and has the goof affinity to the wound surface and an effect of promoting the healing of the wound surface. SOLUTION: This wound coating material consists of a nonwoven fabric layer 11 which consists of hydrophobic fibers and highly absorptive fibers, a polyurethane film layer 12 which has pores and a non-crosslinked hyarulonic acid sponge layer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wound dressing. More specifically, it is applied to a wound surface that exudes a large amount of wound fluid during the healing process, and is suitable for use in promoting wound healing.

[0002]

2. Description of the Related Art Conventionally, as a method for treating a wound caused by a burn, pressure sore (bed sore) or other trauma, a method of applying a remedy to a wound, covering the wound with gauze, and fixing with a covering material. Has been taken. In such a case, since the gauze is directly applied to the wound surface, the exudate from the wound surface is directly absorbed by the gauze, but the gauze does not have a high water absorbing ability, and the exudate is stored. This storage, on the contrary, promotes the generation of bacteria and makes early healing difficult. In particular, on a wound surface with a large amount of exudate from the wound, the ointment or cream of the therapeutic agent mixes with the exudate to form a muddy state. Therefore, it is necessary to frequently change the coating material and reapply the ointment or cream. If the dressing is changed frequently, the amount of medicine to be used increases, and the pain of the patient when changing the dressing increases. There is also a problem that the doctor's labor required for changing the covering material cannot be ignored.

[0003] Films of synthetic materials and the like have been used as a part of the covering material in order to prevent invasion of dirt and bacteria from the outside. However, these materials have a poor function of evaporating moisture. However, there is a drawback that exudate tends to accumulate between the wound surface and the dressing material, thereby delaying wound healing.

Further, from the viewpoint of good affinity with the wound surface and promotion of healing, materials derived from living bodies, for example, glucosaminoglycans such as hyaluronic acid, collagen and the like, are used in the medical field such as wound dressing materials. It has come to be taken up by. However, collagen is abundantly contained in the dermis, tendons, bones, fascia, etc. of animals, and even if it is derived from xenogeneic animals, it can be produced in large quantities because it can reduce immunogenicity if it is converted into atelocollagen by enzymatic treatment. Although it is a useful material that can be obtained relatively inexpensively, it re-fibrils under physiological conditions, and thus requires various hydrophilic treatments and cross-linking treatments. Introducing chemical cross-linking with a cross-linking agent improves shape retention, but there is a problem in that biocompatibility, which can be said to be a characteristic of collagen, is significantly impaired. In addition, because hyaluronic acid had been subjected to a crosslinking reaction for reasons such as suppression of in vivo degradation,
There were problems such as a reduction in the original healing promoting effect of hyaluronic acid.

[0005]

[0003] Wound dressings must have several requirements in order to facilitate wound healing. For example, wound dressings must be highly absorbent and have a high rate of fluid uptake to remove exudate from the wound surface. And it must prevent the absorbed liquid from leaking from the wound dressing and soiling the bedding. The wound dressing must also be breathable so that the wound can breathe and minimize the potential for bacterial infection from the outside to keep the wound as sterile as possible. However, it cannot be said that these requirements have been sufficiently satisfied by the wound dressing materials conventionally used.

[0006] It is therefore an object of the present invention to minimize the possibility of external bacterial infection, to absorb a significant amount of exudate oozing from the wound surface, and to ensure that the Wound dressing that can extend the useful life of the wound dressing by transferring the contained moisture through the wound dressing within the desired rate to the outer surface of the wound dressing and evaporating this moisture into the surrounding environment Is to provide. Further, it is another object of the present invention to provide a wound dressing material having good affinity with a wound surface and having a healing promoting effect on the wound surface.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. The present invention has the following constitution. (1) A wound dressing comprising three layers: a nonwoven fabric layer composed of a hydrophobic fiber and a highly absorbent fiber; a polyurethane film layer having pores; and a non-crosslinked hyaluronic acid sponge layer. (2) The wound dressing according to (1), wherein the basis weight of the nonwoven fabric layer composed of the hydrophobic fiber and the highly absorbent fiber is 30 to 300 g / m ² . (3) The thickness of the polyurethane film layer having openings is 5
The wound dressing according to the above (1) or (2), which has a thickness of １００100 μm. (4) The wound dressing according to any one of (1) to (3) above, wherein the non-crosslinked hyaluronic acid sponge layer is not crosslinked with a crosslinking agent such as an epoxy compound.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As one embodiment of the present invention, FIG.
The structure shown in FIG. That is, the nonwoven fabric layer 11 composed of the hydrophobic fiber and the highly absorbent fiber can absorb a large amount of wound exudate released from the wound surface, and can reduce the moisture contained in the exudate at a desired speed. Has the ability to be transferred through the wound dressing to the exterior surface of the wound dressing to allow this moisture to evaporate into the surrounding environment.
In this way, by allowing the water vapor from the absorbed liquid to escape into the atmosphere, the frequency of replacement of the wound dressing can be reduced.

As the highly absorbent fiber used in the present invention, wood pulp, natural fiber of cotton, rayon, regenerated fiber of cupra, semi-synthetic fiber such as acetate and the like are used. As the hydrophobic fiber, polyester, nylon, acrylic,
Synthetic fibers such as polypropylene and polyethylene are preferred. Particularly, the hydrophobic fiber and the superabsorbent fiber are 6: 4 by weight.
When used in a ratio of 8: 2, the hydrophobic fibers receive water from the highly absorbent fibers that have absorbed the exudate, and serve to evaporate the water in the outer air layer, which is particularly preferable. The thickness of the fiber constituting the nonwoven fabric layer 11 composed of the hydrophobic fiber and the highly absorbent fiber is about 0.3 to 10 denier (d), preferably 0.5
It is desirable that the thickness be about 5 d.

[0010] As a method for producing a nonwoven fabric, it can be produced by a known method, for example, the following method. A wet process in which a short fiber layer (web) is made with water, impregnated with resin, and dried and hardened, just as paper is made. A dry method in which a web is made mechanically without using water and bonded with resin or adhesive fibers. A needle punch method in which a web of the same type as the dry type is pierced with a pierced needle to mechanically entangle the fibers. Spunlace method in which fibers are entangled with a high-pressure water stream on a web of the same type as the dry type. A web with a uniform thickness by arranging a large number of continuous yarns in all directions like a spider web while simultaneously blowing out the melted raw resin from many small holes (nozzles) before forming fibers Spunbonding method, where yarns are naturally and mechanically attached to each other.

The above-mentioned nonwoven fabric layer 11 can also be made by these known methods or by a combination of these methods. . Since the nonwoven fabric used in the present invention must have elasticity, a nonwoven fabric having a relatively large elongation is used. The elongation is length 60cm width 6c
m when a load of 1500 g is hung on a nonwoven fabric
m is expressed as a percentage of the original length.
The nonwoven fabric used in the present invention is preferably 30 to 200
%, More preferably 40 to 150%.

The thickness of the nonwoven fabric layer 11 is preferably 1 to 20 m in consideration of flexibility, durability, workability, absorbability and the like.
m, more preferably about 1 to 10 mm. Woven cloth layer 11, from the viewpoint of retention of exudates, preferably a basis weight 30~300g / m ^2, more preferably, it is preferable that the 50 to 200 g / m ^2.
Non-woven fabric layer 11 composed of the above-mentioned hydrophobic fiber and highly absorbent fiber
Furthermore, the lamination of the polyurethane film layer 12 is effective in suppressing the fluffing of the nonwoven fabric layer 11 and at the same time controlling the flexibility of the wound dressing. Further, since the polyurethane film layer has good adhesion to the non-crosslinked hyaluronic acid sponge layer, there is an advantage that the physical strength and durability of the hyaluronic acid sponge layer can be further improved.

[0013] A polyurethane resin suitable for use in the polyurethane film layer is produced using three components of a diisocyanate, a polyol and a chain extender as basic materials. In the reaction, first, an excess equivalent of diisocyanate is reacted with the polyol at 50 to 120 ° C. to form a urethane prepolymer having an isocyanate group at the terminal, and then the chain is extended with a chain extender at 0 to 100 ° C. in an organic solvent. Good. Here, the equivalent ratio of diisocyanate to polyol in the urethane prepolymer is usually 1.5 to
The ratio is 6: 1, but is preferably 1.8 to 4.5: 1 in order to combine good physical properties and moisture permeability.

The diisocyanate used in the present invention includes 4,4'-diphenylmethane diisocyanate,
m- and p-phenylene diisocyanate, 2,4-
And aromatic diisocyanates such as 2,6-tolylene diisocyanate, isophorone diisocyanate,
4′-dicyclohexylmethane diisocyanate, 1,
Alicyclic diisocyanates, such as 4-cyclohexylene diisocyanate, and aliphatic diisocyanates, such as hexamethylene diisocyanate. Usually, these compounds are used alone, but two or more kinds may be used in combination.

[0015] The polyol used in the present invention includes:
Examples include a polyether polyol, a polyester polyol, and a polycarbonate polyol. And
Examples of the polyether polyol include polypropylene ether glycol and polytetramethylene glycol. Examples of the polyester polyol include polybutylene adipate and polycaprolactone glycol. Also, as the polycarbonate polyol, 1,
6-hexane polycarbonate diol.
Usually, these compounds are used alone, but two or more kinds may be used in combination.

As the chain extender used in the present invention, a low molecular weight diol or a diamine is used. Representative examples of the low molecular weight diol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexamethylene glycol and the like. Representative examples of the low molecular weight diamine include aliphatic diamines such as ethylenediamine, 1,2-propanediamine, tetramethylenediamine, and hexamethylenediamine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 1,4-cyclohexylene. Alicyclic diamines such as diamines; Of these, isophoronediamine is preferable from the balance of various physical properties of the polyurethane layer, and can be used alone or in combination of two or more.

As the organic solvent used for synthesizing the polyurethane of the present invention, solvents having a strong dissolving power such as dimethylformamide, dimethylacetamide and dimethylsulfoxide are suitable. These solvents are used alone or in an aromatic solvent such as toluene and xylene, methyl ethyl ketone, and the like. One or more selected from ketone solvents such as acetone and cyclohexanone, ether solvents such as tetrahydrofuran and dioxane, acetate solvents such as ethyl acetate and butyl acetate, and alcohol solvents such as methanol, ethanol and isopropanol. It can be used as a mixture with two or more kinds.

The concentration of the polyurethane solution is 2 to 30% by weight, preferably 3 to 25% by weight. In the present invention, in order to provide the polyurethane film layer 12 on one side (inside) of the nonwoven fabric layer 11, for example, a solvent coating method, a hot melt coating method, a lamination method, or the like is used.

In the case of the solvent coating method, the polyurethane layer 12 is obtained by uniformly dissolving the polyurethane resin in the solvent, applying the solution on the nonwoven fabric layer 11 and drying the solvent. In the case of the hot-melt coating method, the polyurethane resin is heated and stirred at a temperature of 100 to 220 ° C. under nitrogen replacement to dissolve the non-woven fabric layer 1 using a hot-melt coater.
After being applied on 1, the polyurethane layer 12 is obtained by drying. In the laminating method, first, a polyurethane method is applied on a support by a solvent coating method or a hot melt coating method, and then dried or semi-dried.
Alternatively, a polyurethane layer is formed by a wet method in which a polyurethane resin solution is applied on a support, a solvent or other soluble substances are extracted in a coagulation bath, and then dried or semi-dried.
Next, the polyurethane layer 11 formed by the above method is bonded to the nonwoven fabric layer 12. As a method for laminating, a method of laminating the semi-dried polyurethane layer 12 with the nonwoven fabric layer 11 and then drying, or an organic solvent that moderately swells the surface of the dried polyurethane layer, for example, alcohols such as methanol After swelling with another solvent, there is a method of laminating with the nonwoven fabric layer 11 and drying. Further, a method of laminating both with an adhesive is adopted.
When the nonwoven fabric layer 11 and the polyurethane layer 12 are laminated via an adhesive, if the adhesive is applied to the entire surface, the moisture-permeable function of the polyurethane layer 12 is impaired. Partial bonding is preferred.

The support used when forming the polyurethane layer 12 by the above-mentioned dry method or wet method is not particularly limited, but a release paper coated with a release agent of polyethylene, polypropylene, fluorine or silicone is used. Cloth or the like is used.

The thickness of the polyurethane layer 12 can be adjusted by, for example, the concentration of the polyurethane solution or the amount of the solution to be applied. The thickness of the polyurethane layer 12 is not particularly limited, but is usually 5 to 100 μm, preferably 8 to 50 μm. When the thickness is 5 μm or less, pinholes are easily formed during coating, and the polyurethane layer is easily blocked and is difficult to handle. If it is 50 μm or more, it tends to be difficult to obtain sufficient moisture permeability. Further, the polyurethane layer becomes hard, and the adhesion to the skin tends to be impaired. The polyurethane layer obtained by the above method has practically sufficient strength, elongation and durability.

The wound dressing of the present invention is intended to be applied to a wound surface which exudes a large amount of wound fluid during the healing process, and is used for promoting the healing of the wound. Therefore, even if a polyurethane film having moisture permeability and air permeability is used,
Since a large amount of exudate from the wound surface cannot be permeated, it is necessary to form an opening in the polyurethane film so that the exudate from the wound surface is absorbed by the absorbent fibers of the wound dressing.

The shape of the opening may be a needle hole, a punch hole, a cross, or a single slit. The slits are not limited to those formed at a predetermined interval in the length direction, and may be formed in any shape, such as randomly formed or ring-shaped, and their length is not particularly limited. As a method of forming these openings, for example, a method of rolling a roller or the like in which a number of cutter blades are embedded on the surface of the polyurethane film can be adopted.

In the wound dressing of the present invention, openings may be formed not only in the polyurethane film layer but also in both the polyurethane film layer and the nonwoven fabric layer.

Another object of the present invention is to use a non-crosslinked hyaluronic acid having high biocompatibility.
An object of the present invention is to provide a wound dressing having a wound healing promoting action. That is, hyaluronic acid provides a highly hydrated microenvironment to the wound surface during the wound healing process. In such a microenvironment, it is known that adhesion and detachment between a cell membrane and a substrate when various cells move on a wound surface are controlled, and cell migration is facilitated, so that wound healing is promoted. However, non-cross-linked hyaluronic acid can be expected to have a higher effect than conventional cross-linked hyaluronic acid. In particular, it is preferable that hyaluronic acid be sponge-like in order to improve the adhesion to the wound surface.

Although hyaluronic acid works excellently in the wound healing process, it is easily dissolved in exudates when applied to a living body. Has been deemed unsuitable in its original form. However, according to our study, by concentrating and freeze-drying the aqueous solution of hyaluronic acid,
It was found that a sponge having a sufficiently high retention in a living body could be produced even in a non-crosslinked state. Normally, hyaluronic acid becomes a viscous solution when dissolved in water, and the concentration is limited to 1% for handling. However, at a concentration of 1% or less, there is a problem that a sparse sponge is formed after freeze-drying. The sponge layer having a desired thickness can be produced by condensing by heating to remove moisture by heating at the stage of being put into the tub. There was no difference between the crosslinked hyaluronic acid and the survivability.

As the hyaluronic acid to be used, for example,
Those having a molecular weight of preferably 500,000 to 3,000,000, more preferably about 1,800,000 to 2,200,000 are used. Concentration of the aqueous solution of hyaluronic acid is performed by heating in a thermostat for 5 to 30 hours, preferably 10 to 20 hours to prepare a concentrated aqueous solution of hyaluronic acid. The concentration rate should be appropriately selected depending on the required amount of hyaluronic acid. The reaction may be performed at a temperature of, for example, 30 to 60 ° C, preferably about 40 to 50 ° C, and the reaction time is preferably 5 to 30 hours, more preferably 15 to 20 hours. Generally, it is preferable to use a hyaluronic acid sponge in which about 5 to 30% by weight remains after being implanted in a living body (for example, subcutaneously of a Wistar rat) and left for one week.

The non-crosslinked hyaluronic acid sponge layer is prepared by injecting the above-concentrated aqueous solution of hyaluronic acid into a molding container, and heating at -20 ° C to -100 ° C, preferably -40 to -8 ° C.
It may be manufactured by quenching and freeze-drying in a freezer at 0 ° C. and freeze-drying, or may be manufactured by gradually cooling to −30 to −50 ° C. in a freeze dryer and vacuum drying. . Examples of the method for forming the sponge-like sheet include the freeze-drying method as described above, but are not limited thereto, and those skilled in the art can employ an appropriate method.

The thickness of the non-crosslinked hyaluronic acid sponge layer is
What is necessary is just to set arbitrarily according to the use purpose of a wound dressing material, and an application site | part, Preferably it is 0.5-20 mm, More preferably, it is about 1-10 mm.

The components of the wound dressing of the present invention are
Nonwoven fabric layer, polyurethane film layer and hyaluronic
Any component of the acid sponge layer or all components thereof
It is preferable to mix an antibacterial agent in the component. Antibacterial agent
Are sulfa drugs, penicillin, nalidixin,
Rufadiazine silver, polymyxin sulfate, gentamic sulfate
Although any antibacterial agent such as Shin can be used,
Preferred is a broad antimicrobial spectrum, with the emergence of resistant bacteria
It is difficult to use silver sulfadiazine. antibacterial
The content of the drug depends on the type of drug,
Can be determined according to the application site, but silver sulfadiazine
If used, the content or amount of wound dressing
20-500 μg / cm^Two, Preferably 50-400μ
g / cm ^TwoIt is. With such a content,
At the same time as enabling the suppression of bacterial growth on the wound surface
In addition, cell proliferation inside the wound dressing that absorbed the exudate
It can be suppressed effectively.

The wound dressing material of the present invention is used so that the non-crosslinked hyaluronic acid sponge layer is in contact with the wound surface, and is used in an arbitrary shape such as a bandage shape or a pad shape of several cm square to several tens cm square. be able to. The degree and depth of the wound,
It can be appropriately selected and used depending on the area of the wound surface or the like.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the effects of the present invention will be specifically described. However, the present invention is not limited to the following Examples. Example 1 Production of Nonwoven Fabric Layer 11 Nonwoven fabric layer 11 composed of a hydrophobic fiber and a highly absorbent fiber was
After mixing a polyester fiber having an average fineness of 1.5d and a rayon fiber having a average fineness of 2.0d at a weight ratio of 70:30, a layer (web) of an extremely thin fiber is formed, and the web is overlaid to obtain a basis weight of 120 g /. after so composed in m ^2,
The web layer was stuck with a pierced needle, and the fibers were mechanically entangled with each other (needle punch method). Silver sulfadiazine was applied as an antibacterial agent to the nonwoven fabric layer so as to have a concentration of 50 μg / cm ² .

Example 2 Preparation of Polyurethane Solution 700 parts by weight of polytetramethylene glycol having a number average molecular weight of 2,000 and 180.6 parts by weight of 4,4'-dicyclohexylmethane diisocyanate were placed in a flask at 75 ° C. under dry nitrogen at 75 ° C. After reacting for a period of time to obtain a urethane prepolymer having an isocyanate group at the end, a chain extension reaction was carried out for 2 hours while maintaining the temperature at 20 ° C. using isophoronediamine as a chain extender in a dimethylacetamide solvent, and a polyurethane solid concentration of 25 wt. % Of a clear and viscous polyurethane solution.

Example 3 Preparation of Composite Polyurethane Film Layer (Wound Covering Material for Control Experiment) Methyl ethyl ketone was added to the dimethylacetamide solution containing 25% by weight of the polyurethane resin obtained in Example 2 to prepare a 15% by weight polyurethane solution. . This solution was applied to release paper having a silicon-based film formed on the surface such that the polyurethane layer had a thickness of 10 μm when dried. Next, it was placed in a hot air dryer and dried at 100 ° C. for 3 minutes to remove the solvent. The obtained polyurethane film layer was partially adhered to one surface of the nonwoven fabric layer 11 prepared in Example 1 via an adhesive. Next, the release paper was peeled from the polyurethane layer to obtain a composite layer including the nonwoven fabric layer and the polyurethane layer. Next, a slit-shaped opening having a length of 3 mm is provided linearly at intervals of 10 mm, and the pitch of the lines (parallel spacing between lines) is 10 mm, thereby preparing a composite polyurethane film layer having openings. did.

Example 4 Production of Non-Crosslinked Hyaluronic Acid Wound Dressing First, a 1% aqueous solution (pH = 6) of hyaluronic acid having a molecular weight of 2,000,000 produced by a fermentation method was prepared, and was prepared by adding 200 ml of the internal volume. Polystyrene container (length 10cm, width 1)
(0 cm, height 2 cm), the above-mentioned 1% aqueous solution of hyaluronic acid (200 cc) was injected, and the composite polyurethane film layer produced in Example 3 was cut so as to have a size of 10 cm × 10 cm. I put it on it. The polystyrene container was concentrated by heating in a thermostat set at 50 ° C. for about 10 hours, and then freeze-dried in vacuum to prepare a wound dressing having a non-crosslinked hyaluronic acid sponge layer.

Example 5 Preparation of cross-linked hyaluronic acid wound dressing (control dressing) Similarly, a 1% aqueous solution of hyaluronic acid having a molecular weight of 2,000,000 (p
H = 6), ethylene glycol diglycidyl ether was added as a cross-linking agent in an amount of 1/10 mol based on the molecular weight of the repeating unit of hyaluronic acid. This mixture 1
00 ml was poured into a polystyrene container (10 cm × 10 cm). Next, 10 cm × 10 cm of the composite polyurethane film layer manufactured in Example 3 was placed so that the hyaluronic acid was in contact with the polyurethane film side, and the mixture was allowed to stand in a dryer set at 50 ° C. for 5 hours to perform an intermolecular crosslinking reaction. This was freeze-dried in a vacuum in the same manner as in Example 4 to prepare a wound dressing having a crosslinked hyaluronic acid sponge layer.

Example 6 Animal Experiment The wound dressings obtained in Examples 4 and 5 were sterilized with ethylene oxide gas, and then subjected to the following experiment. That is, the both backs of Wistar rats (8 weeks old) were shaved under anesthesia and disinfected with isodine, and then a full-thickness skin defect wound 20 mm in size on a side was prepared. The wound was produced in Example 4 on the right back. A wound dressing having a non-crosslinked hyaluronic acid sponge layer was applied, and the wound dressing having a crosslinked hyaluronic acid sponge layer prepared in Example 5 was applied to the left back as a control, and gauze was applied thereon to stretch adhesive. Secured with tape. One week later, the dressing was removed under anesthesia, the condition of the wound surface was observed, the wound was disinfected with isodine, and the wound dressing and the control dressing, on which the non-crosslinked hyaluronic acid sponge layer was laminated, were applied again. Gauze and fixed with elastic adhesive tape. Thereafter, a new wound dressing material was replaced every week, and the state of the wound was observed over time.

[0038] The formation of granulation tissue and shrinkage from around the wound are promoted on the right back to which the wound dressing laminated with the non-cross-linked hyaluronic acid sponge layer is applied. Is about 10 × 4mm,
The wound surface was kept appropriately moist during the healing period. On the other hand, the size of the skin defect wound was about 13 × 7 mm and the wound surface was slightly dry at the second week after the application of the coating material on the left back portion to which the coating material having cross-linked hyaluronic acid was applied. Judging comprehensively, the wound dressing laminated with the non-crosslinked hyaluronic acid sponge layer is more effective than crosslinked hyaluronic acid during the healing period in maintaining a moderately moist state with exudative fluids necessary for wound healing, It was assumed that the degree of wound reduction was also high.

[0039]

As described above, the wound dressing according to the present invention has the following effects. Since the nonwoven fabric layer 11 is composed of the hydrophobic fiber and the high-absorbency fiber, it can absorb a large amount of wound exudate released from the wound surface, and can remove water contained in the exudate into a desired amount. The exudate is stored between the wound and the wound dressing because it has the ability to evaporate this moisture into the surrounding environment by passing through the wound dressing at a rate to the outer surface of the wound dressing. Nothing. Therefore, the frequency of changing the wound dressing can be reduced, so that the complexity of the operation is reduced, and the labor of the healer can be greatly reduced. By incorporating the non-crosslinked hyaluronic acid sponge layer having high biocompatibility into the wound dressing, it can be expected that a higher wound healing promoting effect can be obtained as compared with the crosslinked hyaluronic acid wound dressing. By concentrating even non-cross-linked hyaluronic acid, it can remain on the wound surface as well as cross-linked hyaluronic acid, and a sustained wound healing promoting effect can be expected.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a wound dressing according to the present invention.

Claims (4)

[Claims] 1. A wound dressing comprising: a nonwoven fabric layer comprising hydrophobic fibers and superabsorbent fibers; a polyurethane film layer having pores; and a non-crosslinked sponge layer of hyaluronic acid. 2. The wound dressing according to claim 1, wherein the basis weight of the nonwoven fabric layer composed of the hydrophobic fiber and the superabsorbent fiber is 30 to 300 g / m ² . 3. The wound dressing according to claim 1, wherein the thickness of the polyurethane film layer having openings is 5 to 100 μm. 4. The wound dressing according to claim 1, wherein the non-crosslinked hyaluronic acid sponge layer is not crosslinked with a crosslinking agent such as an epoxy compound.