JP2000175959A - Bandage for wound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb a large amount of wound exudate discharged from a wound surface, to vapor moisture contained in the exudate to a peripheral environment and to prolong the life of the bandage by laminating a moisture vapor permeable polyurethane layer and a nonwoven layer consisting of hydrophobic fibers and highly absorptive fibers. SOLUTION: This bandage for a wound, which is provided with an ability to absorb the exuding liquid from the wound and to prevent a leakage from the bandage and wound maceration, is formed by laminating the moisture vapor permeable polyurethane layer 11 and the nonwoven layer 12 consisting of the hydrophobic fibers and the highly absorptive fibers. A polyurethane resin to be suitably used for the polyurethane layer 11 is manufactured with three components, that is, di-isocyanate, polyole and chain lengthening agent as a base material. In the meantime, wood pulp, natural cotton fibers, rayon, cupra reproduced fibers or semi-synthetic fibers such as acetate are used as the highly absorptive fibers and synthetic fibers such as polyester, acryl, polypropylene or polyethylene are used as the hydrophobic fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wound dressing having excellent ability to absorb exudate from a wound and prevent bandage leakage and wound maceration. The wound dressing of the present invention is particularly suited for use on wounds that exude a large amount of wound fluid during the healing process.

[0002]

2. Description of the Related Art Conventionally, as a method of treating a wound caused by a burn, pressure sore (bed sore) or other trauma, a method of applying a therapeutic agent to a wound, covering the wound with gauze, and fixing with a bandage is known. Have 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 accumulation, on the contrary, promotes the outbreak of bacteria and makes early treatment difficult. In particular,
On a wound surface with a large amount of exudate from the wound, since the ointment or cream of the therapeutic agent mixes with the exudate to form a muddy state, it is necessary to frequently change the dressing and change the ointment or cream. If the bandage is changed frequently, the amount of medicine to be used increases, and the pain of the patient during the bandage change increases. In addition, there is a problem that the doctor's labor required for changing the bandage cannot be ignored.

[0003] Further, the bandage for fixing gauze is also usually a woven fabric using cotton yarn or elastic spandex fiber, and the surface is not dense, so that the invasion of microorganisms from the outside cannot be prevented. was there.

[0004]

[0003] Wound dressings must have several prerequisites to promote wound healing. For example, wound dressings must be highly absorbent and have a high fluid uptake rate to remove exudate from the wound surface. And it must prevent the absorbed liquid from leaking out of the bandage and soiling the bedding. The wound dressing must be breathable so that the wound can breathe, and minimize the potential for external bacterial infection, keeping the wound as sterile as possible. However, the above-mentioned conventional method, that is, a method in which a therapeutic agent is applied to a wound, covered with gauze, and then fixed with a bandage, does not satisfy these requirements.

[0005] 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 It is an object of the present invention to provide a wound dressing in which the moisture contained therein is transferred through the dressing to the outer surface of the dressing within a desired speed, and the effective life of the dressing can be extended by evaporating this moisture into the surrounding environment. .

[0006]

Means for Solving the Problems The present inventors have made various studies to solve the above-mentioned problems, and as a result, completed the present invention. An object of the present invention is to provide a moisture-permeable film layer and a hydrophobic fiber. And a nonwoven fabric layer made of superabsorbent fibers.

That is, the present invention has the following configuration. (1) A wound dressing comprising a laminate of a moisture-permeable polyurethane layer, a nonwoven fabric layer composed of hydrophobic fibers and superabsorbent fibers. (2) The wound dressing according to (1), wherein the moisture-permeable polyurethane layer has a thickness of 5 to 100 μm. (3) (1) or (2), 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.
Wound dressing.

[0008]

FIG. 1 shows an embodiment of the present invention. That is, the nonwoven fabric layer 12 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. Have the ability to be transferred through the bandage to the outer surface of the bandage, allowing this moisture to evaporate into the surrounding environment. In this way, by allowing water vapor from the absorbed liquid to escape into the atmosphere, the frequency of changing 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.
The use of a ratio of 8: 2 is particularly preferable because the hydrophobic fiber receives moisture from the highly absorbent fiber that has absorbed the exudate and plays a role in evaporating the moisture in the outer air layer. The thickness of the fibers constituting the nonwoven fabric layer 12 composed of the hydrophobic fibers and the highly absorbent fibers is preferably about 0.3 denier (d) to about 5 d, and more preferably about 0.5 to 3 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 12 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 12 is preferably 1 to 20 in consideration of flexibility, durability, workability, absorbability and the like.
mm, more preferably 1 to 10 mm. Woven cloth layer 12, from the viewpoint of retention of exudates, which is preferably a basis weight 30~300g / m ^2, more preferably preferably those 50 to 200 g / m ^2.

The skin has a respiratory function such as skin respiration and water vapor transmission, and a barrier function such as prevention of bacterial invasion and retention of body fluid. Therefore, a wound dressing used for treating wounds caused by burns, pressure ulcers, and other traumas preferably has both functions. Suitable gas and water vapor permeable materials include polyurethane.

The wound dressing of the present invention is obtained by laminating a nonwoven fabric layer 12 made of a hydrophobic fiber and a highly absorbent fiber on the side opposite to the wound surface (outside) with a polyurethane layer 11 having excellent moisture permeability as a surface material. It is. Moisture-permeable polyurethane layer 11
Is provided to protect the outer surface of the nonwoven fabric layer 12 that has absorbed the body fluid, thereby preventing contamination due to external contact and having appropriate gas and water vapor permeability.

It is necessary to determine how much water vapor permeable material should be used for the polyurethane layer 13 on the basis of the amount of water dissipated from the wound surface. The amount of water dispersion of the skin is about 200 gH ₂ O / m ² · 24 hr in healthy skin.
s, about 300 gH ₂ O / m ² · 24 hr for degree burn wound
s, about 4300 g H ₂ O / m ² · 24 h for burn wounds
rs, 3400 gH ₂ O / m ² · 24 h for burn wound
rs, about 5,100 g H ₂ O / m ² · 24 from granulation wound
hrs, approx. 3600 g H ₂ O / m ² · 24 from skin wound
hrs.

If the moisture permeability of the moisture-permeable polyurethane layer 11 is too low, the wound portion becomes humid, causing maceration around the wound portion. On the other hand, even if the moisture permeability is too high, the wound part is dried and hardly healed. Therefore, considering the above water dispersion loss as a preferable moisture permeability, 300
６6000 gH ₂ O / m ² · 24 hrs. Considering the use as a wound dressing particularly exudative large amount of dressing of the present invention, moisture permeability 3000~6000gH ₂ O
/ M ² · 24 hrs is preferable.

Polyurethane resins suitable for use in the moisture-permeable polyurethane layer 11 of the present invention include diisocyanates,
It is produced using three components of a polyol and a chain extender as basic raw 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 between the diisocyanate and the polyol in the urethane prepolymer is usually 1.5 to 6: 1, but it should be 1.8 to 4.5: 1 in order to combine good physical properties and moisture permeability. Is preferred.

The diisocyanate used in the present invention includes 4,4'-diphenylmethane diisocyanate, m- and p-phenylene diisocyanate,
Aromatic diisocyanates such as 4- and 2,6-tolylene diisocyanate, isophorone diisocyanate, 4
-4'-dicyclohexylmethane diisocyanate,
Examples thereof include alicyclic diisocyanates such as 1,4-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.

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 may be 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 layer 11 on one side (outside) of the nonwoven fabric layer 12, 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 11 is obtained by uniformly dissolving the polyurethane resin in the solvent, applying the solution on the nonwoven fabric layer 12 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 2, the polyurethane layer 11 is obtained by drying.

In the laminating method, first, polyurethane is first applied on a support by a solvent coating method or a hot melt coating method and then dried or semi-dried by a dry method, or a polyurethane resin solution is applied on the support and solidified. After the solvent and other soluble substances are extracted in the bath, the polyurethane layer is formed by a wet method of drying or semi-drying. Next, the polyurethane layer 11 formed by the above method is applied to the nonwoven fabric layer 1.
Attach to 2. As a method of laminating, after laminating the semi-dry polyurethane layer 11 with the nonwoven fabric layer 12,
There is a method of drying, or a method of swelling the surface of the dried polyurethane layer with an organic solvent that appropriately swells, for example, an alcohol such as methanol, or another solvent, and then laminating the resultant with the nonwoven fabric layer 12 and drying. Further, a method of laminating both with an adhesive is adopted. When the nonwoven fabric layer 12 and the polyurethane layer 11 are laminated via an adhesive, if the adhesive is applied to the entire surface, the function of the moisture-permeable polyurethane layer is impaired. Good adhesion.

The support used when forming the polyurethane layer 11 by the above-mentioned dry method or wet method is not particularly limited, but a release paper or a release paper coated with a polyethylene, polypropylene, fluorine or silicone release agent is used. Cloth or the like is used.

The thickness of the polyurethane layer 11 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 11 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 film 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 film 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. still,
The wound dressing of the present invention can be freely modified by containing an antibacterial agent such as a sulfa drug, penicillin, nalidixin, silver sulfadiazine, polymyxin sulfate, and gentamicin sulfate in the polyurethane layer 11 for the purpose of preventing bacterial infection. Can be done.

The wound dressing according to the present invention has a width of 3 to 10 cm and a length of 30 to 3 when wound on a hand or foot.
Preferably, it is wound in a bandage of 00 cm. When used in the form of a pad instead of gauze, the vertical / horizontal 5
A pad shape of about 30 cm is preferred.

[0028]

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 Preparation of Polyurethane Solution 700 parts by weight of polytetramethylene glycol having a number average molecular weight of 2000 and 180.6 parts by weight of 4,4'-dicyclohexylmethane diisocyanate were placed in a flask under dry nitrogen at 75 ° C. for 5 hours. After reacting to obtain a urethane prepolymer having an isocyanate group at the end, a chain elongation reaction was carried out for 2 hours using isophoronediamine as a chain extender in a dimethylacetamide solvent while maintaining the temperature at 20 ° C. to obtain a polyurethane solid concentration of 25 wt%. A colorless, transparent and viscous polyurethane solution was obtained.

Example 2 Production of Nonwoven Fabric Layer 12 The nonwoven fabric layer 12 composed of hydrophobic fibers and superabsorbent fibers is composed of a polyester fiber having an average fineness of 1.5 d and a rayon fiber having a mean size of 2.0 d in a weight ratio of 70/30. Then, an extremely thin fiber layer (web) is formed, and the webs are superimposed on each other so that the basis weight is 120 g / m ^2. Were mechanically entangled with each other (needle punch method).

Example 3 Preparation of Wound Dressing A 15 wt% polyurethane solution was prepared by adding methyl ethyl ketone to the dimethylacetamide solution containing 25 wt% of the polyurethane resin obtained in Example 1. 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 layer was used in Example 2.
Was partially adhered to one surface of the nonwoven fabric layer 12 prepared in the above through an adhesive. Next, the release paper was peeled from the polyurethane layer to obtain a wound dressing.

The moisture permeability of the polyurethane layer is JIS-Z-0.
Under the conditions of 40 ° C and 90% RH according to
It was determined by weight measurement using a pump. Its value is 4,500
gH _TwoO / m^Two-It was 24 hrs. Like this
Weigh to determine the absorbency of the created wound dressing
Soak the wound dressing in water, remove it,
After dripping, it was weighed again to determine the amount of water absorbed. This
Has an extremely high absorption capacity of 19 g / g
It has been found. Therefore, if there is a lot of exudate from the wound surface
Suitable for combined wound dressings.

Example 4 Preparation of Wound Dressing A 15% by weight polyurethane solution was prepared by adding methyl ethyl ketone to the dimethylacetamide solution containing 25% by weight of the polyurethane resin obtained in Example 1. This solution was applied to release paper having a silicon-based film formed on the surface so that the thickness of the polyurethane layer became 20 μm when dried. Next, the polyurethane layer formed on the release paper was immersed together with the release paper in a water bath at a water temperature of 30 ° C. for 30 seconds. Then, 3.0 kg / c by a pressing machine equipped with rubber mangle
By pressing with a pressing force of m ² , the solvent remaining in the polyurethane layer was extruded together with water. The immersion in water and the pressing of the polyurethane layer were repeated a total of five times to increase the removal rate of the solvent remaining in the polyurethane layer.

Next, the polyurethane layer together with the release paper was placed in a hot air drier and dried at 100 ° C. for 30 seconds. The resulting semi-dried polyurethane layer was attached to one surface of the nonwoven fabric layer 12 prepared in Example 2, and then dried to bond the nonwoven fabric layer 12 and the polyurethane layer 11. Next, the release paper was peeled from the polyurethane layer to obtain a wound dressing.
The moisture permeability of the polyurethane layer is 5300 gH ₂ O / m ² · 2
4 hrs. It was also found that the wound dressing thus prepared had an extremely high water absorption capacity of 20 g / g. Therefore, it is suitable for a dressing for a wound when there is a large amount of exudate from the wound surface.

Example 5 The wound dressings obtained in Examples 3 and 4 were sterilized with ethylene oxide gas, and then subjected to the following experiment. That is, a 10-week-old SD rat (body weight 200 to 23) under anesthesia
0g), after shaving the back and disinfecting with Isodine®, a 3 cm × 4 cm back skin full thickness incision was surgically made, where the wound dressing made in Examples 3 and 4 was applied. It was applied separately and fixed thereon with an elastic band, and the condition of the bandage and the wound surface after one week and two weeks was visually observed.

One week later, in all of the wound dressings according to Examples 3 and 4, traces of absorption of body fluid were observed in a part of the dressing, but the dressing itself was dry. Then, the exudate coming out of the wound surface was sucked up by the nonwoven fabric layer, and no exudate was stored in the wound surface, and good granulation tissue with vascular proliferative was observed.

After two weeks, traces of body fluid absorption were observed in approximately half the thickness direction of the bandage using the wound bandages according to Examples 3 and 4, but the bandage itself was It was dry. The exudate from the wound surface was sucked up by the nonwoven fabric layer, and the accumulation of the exudate on the wound surface was small, and only a small amount of the fibrin-like substance was attached. When the fibrin-like substance was removed, very good granulation tissue was observed, and the formation of the epidermis by the proliferation of epidermal cells from the wound margin was also good. In each case, the healing effect was good, and it was found that it was suitable as a wound dressing.

[0038]

As described above, the wound dressing according to the present invention has the following effects. A moisture permeable polyurethane layer 11 is applied to the outer surface of the wound dressing.
This prevents dirt and bacteria from entering the wound surface from the outside, while preventing the absorbed body fluid from leaking from the bandage or soiling the bedding. Since the nonwoven fabric layer 12 is composed of hydrophobic fibers and high-grade aqueous fibers, it 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 rate. The exudate does not accumulate between the wound and the wound dressing because it has the ability to pass through the dressing to the outer surface of the dressing and evaporate this moisture into the surrounding environment. Therefore, the frequency of bandage replacement can be reduced, so that the complexity of the operation is reduced and the trouble of the healer can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the present invention.

Claims (3)

[Claims] 1. A wound dressing comprising a laminate of a moisture-permeable polyurethane layer, a nonwoven fabric layer composed of hydrophobic fibers and superabsorbent fibers. 2. The moisture-permeable polyurethane layer having a thickness of 5 to 10
The wound dressing according to claim 1, which is 0 µm. 3. 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 .