WO2021070915A1

WO2021070915A1 - Antibacterial sheet-like structure

Info

Publication number: WO2021070915A1
Application number: PCT/JP2020/038206
Authority: WO
Inventors: 玄人山口; 雄一原
Original assignee: 旭化成株式会社
Priority date: 2019-10-10
Filing date: 2020-10-08
Publication date: 2021-04-15

Abstract

Provided is a wound dressing sheet capable of maintaining sustained-release antibacterial particles in a wound site at a high concentration. An antibacterial sheet-like structure according to the present invention, and an antibacterial medical material or an antibacterial wound dressing containing the same are characterized by being an antibacterial sheet-like structure containing carboxymethylcellulose (CMC) fibers in which silver-containing particles are present in a fiber surface layer, and having the following (1) to (4): (1) the average degree of substitution of the CMC is 0.1-1.0; (2) the amount of Ag with respect to the weight of the CMC fibers is 0.01-5.0 wt%; (3) the average particle size of the silver-containing particles is 0.01-5 μm; and (4) the silver-containing particles are uniformly distributed in the thickness direction of the antibacterial sheet-like structure.

Description

Antibacterial sheet-like structure

The present invention is a sheet-like structure containing natural or regenerated cellulose fibers containing carboxymethyl cellulose (hereinafter, also abbreviated as CMC) to which silver-containing antibacterial particles are attached (hereinafter, also referred to as an antibacterial gelled sheet). .). Further, carboxymethyl cellulose to which silver-containing antibacterial particles are attached is also abbreviated as CMC / Ag. More specifically, the present invention relates to an antibacterial gelled sheet containing CMC / Ag that slowly releases antibacterial particles by its own gelling ability.

When a wound or surgical wound occurs on human skin or the like, a wound dressing or a wound protective material such as a surgical dressing is used to protect the wounded part.
The following Patent Document 1 describes soluble wound healing hemostatic cellulose fibers having a CMC substitution degree of 0.5 or more and less than 1.0, and also describes that CMC has a cell adhesion promoting action.
Further, Patent Document 2 below also describes that when CMC is applied to a wound, an insoluble foreign substance having a risk of causing inflammation of the wound does not remain. It is also known that CMC has bioabsorbability.

CMC generally used for medical purposes is widely used as sodium carboxymethyl cellulose (hereinafter, also abbreviated as CMC-Na) in which sodium is bonded to a carboxymethyl group. Further, in a situation where antibacterial performance is particularly required, carboxymethyl cellulose silver (hereinafter, also abbreviated as CMC-Ag) in which silver is bonded to the carboxymethyl group of CMC is used.

Many silver compounds have antibacterial properties, and these particles are sometimes used as antibacterial agents, but when antibacterial particles are simply sprayed on the surface of the wound dressing, the antibacterial particles flow out from the wound over time. -Because it diffuses, it cannot maintain sufficient antibacterial properties if it is used for a long period of time.

In order to enhance the sustainability of antibacterial properties, there are methods of kneading antibacterial particles into the fibers and methods of uniformly distributing them as ions in the fibers as in the case of CMC-Ag described above. Since there is silver that is taken into the inside and does not move to the vicinity of the affected area, there is a problem that high antibacterial performance cannot be exhibited against the amount of introduced silver.

Japanese Unexamined Patent Publication No. 2000-256958 JP-A-2002-143210

In view of the current state of the art described above, an object to be solved by the present invention is to provide a wound dressing sheet capable of maintaining a high concentration of sustained-release antibacterial particles in a wound.

The present inventors immerse a structure containing natural or regenerated cellulose fibers carboxymethylated to a predetermined degree of substitution in a solution of silver salt adjusted to a predetermined concentration, and then perform a predetermined treatment to carry out a predetermined treatment to obtain a silver amount. CMC / Ag can be produced by controlling the region where silver and silver are present, and by controlling the degree of substitution of CMC / Ag and the counter cation within a predetermined range, the particles are gradually released when the CMC / Ag gels when wet. It was unexpectedly found that the sex could be controlled, and the present invention was completed based on these findings.

That is, the present invention is as follows.
[1] An antibacterial sheet-like structure containing carboxymethylcellulose (CMC) fibers in which silver-containing particles are present on the fiber surface, and the following (1) to (4):
(1) The average degree of substitution of the CMC is 0.1 or more and 1.0 or less;
(2) The amount of Ag with respect to the weight of the CMC fiber is 0.01% by weight or more and 5.0% by weight or less;
(3) The average particle size of the silver-containing particles is 0.01 μm or more and 5 μm or less; and (4) the silver-containing particles are uniformly distributed in the thickness direction of the antibacterial sheet-like structure;
An antibacterial sheet-like structure characterized by.
[2] The antibacterial sheet-like structure according to the above [1], wherein the silver-containing particles are particles containing at least one selected from the group consisting of metallic silver, silver nanoparticles, silver halide, and silver sulfaziazine. body.
[3] The antibacterial sheet-like structure according to the above [1] or [2], wherein the amount of liquid absorbed when impregnated with the pseudo-exudate is 5 g / 100 cm ² or more and 70 g / 100 cm ^{2 or less.}
[4] The antibacterial sheet-like structure according to any one of [1] to [3] above, wherein the counter cation of the CMC is at least one selected from the group consisting of sodium ions or protons.
[5] The antibacterial sheet-like structure according to any one of [1] to [4] above, wherein 5% or more and 80% or less of the carboxymethyl group of the CMC is protonated.
[6] The antibacterial sheet-like structure according to any one of [1] to [5] above, wherein the CMC fiber is a fiber derived from cuprammonium rayon.
[7] The antibacterial sheet-like structure according to any one of [1] to [6] above, wherein the CMC fiber is a continuous length fiber.
[8] The antibacterial sheet-like structure according to any one of [1] to [7], wherein the number average fiber diameter of the CMC fibers is 1 μm or more and 100 μm or less.
[9] The antibacterial sheet-like structure according to any one of [1] to [8] above, which is in the form of a woven fabric, a knitted fabric, or a non-woven fabric.
[10] The antibacterial sheet-like structure according to any one of [1] to [9] above, wherein the basis weight is 10 g / m ² or more and 200 g / m ^{2 or less.}
[11] The antibacterial sheet-like structure according to any one of [1] to [10], wherein the thickness is 0.03 mm or more and 2.0 mm or less.
[12] The above-mentioned [1] to [11], wherein the coefficient of variation of the number of silver-containing particles per ^{1000 μm 2 in} each of the ranges divided into five in the thickness direction in the structure is 0.5 or less. Antibacterial sheet-like structure.
[13] An antibacterial medical material containing the antibacterial sheet-like structure according to any one of the above [1] to [12].
[14] An antibacterial wound dressing containing the antibacterial sheet-like structure according to any one of the above [1] to [12].

When the wound is healed by using the antibacterial sheet-like structure according to the present invention, the antibacterial property is maintained for a long time by maintaining the silver-containing particles, which are the sustained-release antibacterial particles, at a high concentration in the wound. , It is possible to promote wound healing. In addition, the antibacterial sheet-like structure according to the present invention can exhibit high antibacterial properties from an initial stage as compared with a material in which silver is directly bonded as an ion to a similar material.

Hereinafter, embodiments of the present invention will be described in detail.
In the present specification, the antibacterial sheet-like structure (also referred to as an antibacterial gelled sheet) refers to a sheet-like structure having an antibacterial action and capable of forming a gel by containing water.
In the present specification, the antibacterial medical material refers to a structure having an antibacterial action and promoting wound healing. Examples thereof include, but are not limited to, adhesive plasters, pressure ulcers, wound dressings used for hydrocolloid dressing such as burns, and surgical hemostatic materials.
In the present specification, the antibacterial wound dressing refers to a wound dressing having an antibacterial action.

The natural or regenerated cellulose fiber used as a raw material for the CMC fiber in the present embodiment is not particularly limited, and known cellulose fibers such as cuprammonium rayon, viscose rayon, lyocell, cotton, pulp and polynosic are preferably used. Is cuprammonium rayon, viscose rayon, and more preferably cuprammonium rayon. Some cellulose fibers use a cellulose material with a low degree of polymerization. With such a material, if the degree of substitution is high, the fibers are easily decomposed and it is necessary to suppress the degree of substitution to the lowest possible, whereas cuprammonium rayon is used. When used, it has the advantages of high degree of polymerization and resistance to disintegration even at a relatively high degree of substitution, and it is possible to select a wide range of degrees of substitution.

The natural or regenerated cellulose fibers constituting the CMC fibers in the present embodiment may be either long fibers or short fibers. Of the long fibers, continuous long fibers are preferable. In the present specification, the long fiber means a fiber having a fiber length of 10 mm or more, and the fiber length is preferably 20 mm or more, more preferably 50 mm or more, and further preferably a continuous long fiber. Since the short-fiber cellulose non-woven fabric is a short fiber, the fibers are easily separated when the degree of substitution is high, and it is necessary to suppress the degree of substitution as low as possible. It has the advantage of being resistant to disintegration, and a wide range of substitution degrees can be selected.

The natural or regenerated cellulose fibers constituting the CMC fibers in the present embodiment preferably have a number average fiber diameter of 1 μm or more and 100 μm or less. It is more preferably 1 μm or more and 50 μm or less, and further preferably 5 μm or more and 30 μm or less. When the number average fiber diameter is 1 μm or more, the single yarn strength can be secured and the workability at the time of sheeting is excellent. On the other hand, when the number average fiber diameter is 100 μm or less, spinning and entanglement are easy to occur and the sheet is formed. Excellent workability.

The form of the antibacterial sheet-like structure of the present embodiment is preferably a cotton-like, woven-like, knit-like or non-woven fabric-like form. A more preferable form is a woven fabric or non-woven fabric of CMC-generated recycled cellulose fiber, a more preferable form is a non-woven fabric of CMC-generated recycled cellulose fiber, and a more preferable form is a non-woven fabric of CMC-modified cuprammonium rayon. In the non-woven fabric form, the fibers are entangled even in a gelled state when wet, so that appropriate flexibility can be obtained while maintaining the strength when wet, and the scratches when attached to a scratch. It is easy to attach the hemostatic material along the shape of. If the fibers constituting such a non-woven fabric are cuprammonium rayon, the degree of crystallinity is low, so that the reactivity at the time of carboxymethylation is high and the morphological stability is also excellent. Further, in the case of a non-woven fabric, a non-binder non-woven fabric is preferable because the permeation rate of the solution is slow in the non-woven fabric to which the binder is applied and there is a concern that the binder component may elute when used on scratches.

The antibacterial sheet-like structure of the present embodiment includes fibers other than carboxymethyl cellulose fibers, for example, synthetic fibers such as cellulose fibers, polyester fibers, polypropylene fibers, nylon fibers, and polyglycol, as long as the desired effects are not impaired. Bioabsorbable fibers such as acid, polylactic acid, and polyapple acid may be contained. As a range that does not impair the desired effect, such a material is preferably 50% by weight or less, and more preferably 30% by weight or less. Such fibers may be long fibers or short fibers.

By setting the degree of substitution of the CMC fiber portion in the present embodiment to the optimum range, all or part of the silver-containing particles existing on the fiber surface layer can be buried in the fiber when wet, and the silver-containing particles are released. By making it difficult, the desired antibacterial performance can be maintained for a long time. The CMC moiety in the present embodiment needs to have an average degree of substitution (DS) of hydroxyl groups in the glucose unit constituting cellulose with carboxymethyl groups of 0.1 or more and 1.0 or less, preferably 0. .2 or more and 0.8 or less, more preferably 0.3 or more and 0.6 or less. If the DS is less than 0.1, sufficient gelation performance cannot be exhibited, so that the amount of silver-containing particles released becomes too high, and the desired antibacterial performance cannot be maintained for a long time. On the other hand, if the degree of substitution exceeds 1.0, the solubility of CMC becomes high and the amount of silver-containing particles released becomes too high, so that the desired antibacterial performance cannot be maintained for a long time.

Further, the silver content in the antibacterial sheet-like structure of the present embodiment is 0.01% by weight or more and 5.0% by weight or less in terms of the weight ratio with respect to the antibacterial sheet-like structure in order to obtain sufficient antibacterial properties. It is necessary that the weight is 0.5% by weight or more and 3% by weight or less, and more preferably 0.1% by weight or more and 1% by weight or less. If the silver content is less than 0.01% by weight, sufficient antibacterial properties cannot be exhibited, while if the silver content exceeds 5% by weight, the antibacterial properties are difficult to increase and the antibacterial properties are difficult to increase. May adversely affect the wound.

The silver-containing particles of the present embodiment need to be uniformly distributed in the thickness direction of the sheet-like structure.
In the present specification, the term "silver-containing particles are uniformly distributed in the thickness direction of the sheet-like structure" does not mean that the silver-containing particles are present only on the surface of the sheet-like structure. It is a state in which it exists even inside the sheet-like structure and is dispersed and distributed substantially uniformly. Specifically, as will be described later, a scanning electron microscope is used to observe a range in which the cross section of the sample is divided into five in the thickness direction of the sample, and the number of particles per ^{1000 μm 2 of each is measured.} When the coefficient of variation (coefficient of variation = average value / standard deviation) of the number of these particles is 0.5 or less, it is assumed that the particles in the structure are uniformly distributed in the thickness direction of the structure. ..
If the silver-containing particles are uniformly distributed in the thickness direction of the sheet-like structure, the silver-containing particles existing inside the sheet are embedded in the gel-like sheet when the fibers are gelled. Therefore, it is difficult for the sheet to flow out of the sheet, and the desired antibacterial performance can be maintained for a long period of time. On the other hand, when the silver-containing particles are present only on the sheet surface due to powder spraying or the like, the silver-containing particles are likely to fall off and flow out, and the desired antibacterial performance cannot be maintained for a long period of time.

To adjust the silver-containing particles to be uniformly distributed in the thickness direction of the sheet-like structure, for example, silver nitrate adjusted to a predetermined concentration using an alcohol aqueous solution when introducing the silver-containing particles into the structure. It is preferable to immerse in a solution, drain the silver nitrate solution, and then immerse in an aqueous solution of a halide-containing alcohol such as sodium chloride to precipitate silver-containing particles on the fiber surface.
If the silver nitrate solution is not drained, the unreacted silver nitrate remaining in the solution reacts with the halide to form silver halide particles in the solution, which are deposited on the sheet-like structure. As a result, the distribution of silver-containing particles in the thickness direction becomes uneven. By draining the silver nitrate solution, unreacted silver nitrate is removed from the reaction solution, and the silver-containing particles are uniformly distributed in the thickness direction of the sheet-like structure.

The average particle size of the silver-containing particles of the present embodiment needs to be 0.01 μm or more and 5 μm or less, preferably 0.1 μm or more and 5 μm or less, and more preferably 0.5 μm or more and 2 μm or less. If the average particle size is smaller than 0.01 μm, silver-containing particles are likely to be released from the sheet, and it is difficult to maintain the desired antibacterial performance for a long period of time. On the other hand, when the average particle size is 5 μm or more, the release of silver particles from the sheet is physically blocked by the fibers, and the antibacterial performance is lowered.

The silver-containing particles of the present embodiment are not particularly limited, but are preferably particles containing at least one selected from the group consisting of metallic silver, silver nanoparticles, silver halide, and silver sulfaziazine. These particles have a track record of being used as antibacterial agents in the medical field, and when they are used, they can exhibit desired antibacterial performance when the sheet-like structure is applied to a wound. Further, the silver-containing particles may be particles in which the above compound and other compounds such as silver chloride and sodium chloride are mixed.

The counter cation of the CMC moiety in the present embodiment is not particularly limited, but is preferably selected from sodium ion or proton. The CMC moiety has a sodium salt at the end of the carboxymethyl group at the time of carboxymethylation with, for example, sodium monochloroacetate, but is then treated with an acid solution to treat all or part of the carboxymethyl group. The counter cation of can be changed to a proton (protonation). When a part of the counter cation is a proton, the ratio is preferably 5% or more and 80% or less, more preferably 5% or more and 60% or less, and further preferably 10% or more and 40% or less. By protonating a part of the counter cation, the solubility of the CMC fiber can be adjusted to control the amount of silver-containing particles released, and the desired antibacterial performance can be maintained for a long period of time. Further, counter cations other than sodium ions and protons may be introduced in order to impart other functions, and the amount of these introduced can be adjusted according to the amount of liquid absorbed and the strength at the time of wetting.

When the antibacterial sheet-like structure of the present embodiment is in the form of a woven fabric, a knitted fabric, or a non-woven fabric, its texture (weight of non-woven fabric (g) / non-woven fabric area (m ² )) (g / m ² ) is 10 g. / M ² or more and 200 g / m ² or less, more preferably 30 g / m ² or more and 180 g / m ² or less, still more preferably 40 g / m ² or more and 170 g / m ² or less, still more preferably 50 g. / M ² or more and 150 g / m ² or less. If the basis weight is too low, it may be difficult to obtain sufficient strength even if it is partially protonated. On the other hand, if the basis weight is too high, the flexibility is lost and placement on scratches having uneven portions or the like is complicated. become.

The thickness of the antibacterial sheet-like structure of the present embodiment in a dry state is preferably 0.03 mm or more and 5.0 mm or less, more preferably 0.03 mm in the case of a woven fabric, a knitted fabric, or a non-woven fabric. It is 3.0 mm or more, and more preferably 0.03 mm or more and 2.0 mm or less. If the thickness is too thin, sufficient strength may not be obtained even if it is partially protonated. On the other hand, if the thickness is too thick, the flexibility is lost and the arrangement on scratches becomes complicated. In the present specification, the thickness of the antibacterial sheet-like structure refers to a value obtained by measuring a load of 1.96 kPa in a thickness test conforming to JIS-L1096, for example, in the case of a non-woven fabric.

The amount of liquid absorbed by the antibacterial sheet-like structure of the present embodiment when impregnated with the pseudo-exudate ^{is preferably 5 g / 100 cm 2} or more and 70 g / 100 cm ² or less, more preferably 10 g / 100 cm ² or more. It is 60 g / 100 cm ² or less, more preferably 10 g / 100 cm ² or more and 50 g / 100 cm ² or less. If the amount of liquid absorbed is ^{less than 5 g / 100 cm 2} , the exudate cannot be efficiently retained, and the healing ability may be reduced. On the other hand, if the amount of liquid absorbed is ^{larger than 70 g / 100 cm 2} , the antibacterial sheet-like structure swells greatly and it becomes difficult to maintain the optimum arrangement.

An example of a method for producing a continuous length fiber cuprammonium rayon nonwoven fabric is shown below, but the method is not limited to this method.
A stock solution obtained by dissolving a cotton linter having an adjusted degree of polymerization in a copper ammonium solution from which foreign substances have been removed is extruded from a spinneret (spinning spout) having pores (stock solution discharge holes), and is dropped in the funnel together with water. While coagulating the undiluted solution by deammonia, it is stretched and shaken onto the net to form a web. At this time, by vibrating the net in the direction perpendicular to the traveling direction while advancing the net, the fibers shaken off to the net draw a sine curve. The drawing during spinning can be 100 to 500 times, and the drawing ratio can be arbitrarily adjusted by changing the shape of the spinning funnel and the amount of spinning water flowing through the funnel. By changing the draw ratio, it is possible to change the single fineness and the strength of the non-woven fabric. It is also possible to control low molecular weight cellulose, so-called hemicellulose, which remains in a trace amount in the stock solution by changing the amount of spinning water and the temperature. Further, by controlling the traveling speed and the vibration width of the net, it is possible to control the fiber arrangement direction and control the strength and elongation of the non-woven fabric.

Further, an example of a method for producing short fiber or long fiber ammonia rayon is shown below, but the method is not limited to this method.
A stock solution obtained by dissolving a cotton linter having an adjusted degree of polymerization in a copper ammonium solution from which foreign substances have been removed is extruded from a spinneret (spinning spout) having pores (stock solution discharge holes), and dropped in a funnel together with water. It is possible to obtain long-fiber ammonia rayon by drawing while coagulating the stock solution by deammonizing, and further by cutting the fiber to an arbitrary length to obtain short-fiber ammonia rayon. Further, as in the case of the continuous long fiber cuprammonium rayon non-woven fabric, it is possible to change the single fineness and the strength of the non-woven fabric by changing the draw ratio.
These short fiber or long fiber ammonia rayon can be made into a non-woven fabric by a needle punch method or a spunlace method, but is not limited to this method. The non-woven fabric may be formed at any time before and after the treatment described in the following paragraphs [0026] to [0028]. Since the carboxymethyl cellulose fiber is a fiber that absorbs water and gels, the spunlace method using water is not suitable for making a non-woven fabric after the treatment in the following paragraph [0026], and a needle punch method or an organic solvent is used. It is preferable to make a non-woven fabric by the spunlace method used.

An example of a method for producing the antibacterial sheet-like structure of the present embodiment is shown below, but the method is not limited to this method.
First, the structure of natural or regenerated cellulose fibers is stirred at 35 ° C. for 30 minutes while maintaining an alkaline state in an alcohol-containing sodium hydroxide aqueous solution. Then, after draining the reagent in the reaction vessel, sodium monochloroacetate containing alcohol is added, and the mixture is stirred at 30 ° C. to 55 ° C. for 1 to 12 hours. At that time, the degree of substitution is controlled by the bath ratio of the reaction solution and the structure, the temperature, and the time. In addition, other reaction conditions can be appropriately changed in consideration of production cost and the like. The obtained structure is adjusted to pH 6.0 to 8.0 with an aqueous acetic acid-containing ethanol solution, and then alcohol substitution is performed with 70% by weight, 90% by weight, or 100% by weight of ethanol. Since it becomes hard when it contains even a small amount of water, it is possible to reliably perform alcohol substitution and maintain morphological stability by gradually increasing the alcohol concentration. Then, it is immersed in an acid-containing ethanol solution adjusted to a predetermined concentration, stirred for 1 hour, alcohol-substituted with 70% by weight, 90% by weight, and 100% by weight ethanol, and dried to obtain a protonated sheet-like structure. .. Further, the mixture was immersed in a silver nitrate-containing ethanol aqueous solution adjusted to a predetermined concentration, stirred for 1 hour, then the silver nitrate-containing ethanol aqueous solution was drained, immersed in a sodium chloride-containing ethanol aqueous solution adjusted to a predetermined concentration, stirred for 1 hour, and 70% by weight. Alcohol substitution is carried out with%, 90% by weight and 100% by weight of ethanol, and the mixture is dried to obtain an antibacterial sheet-like structure.
The step of dipping in the acid may be carried out at the same time as the step of neutralization. That is, normally, two steps are required to carry out the acid dipping step after the neutralization step, but the neutralization step and the acid dipping step may be carried out at the same time in one step. Further, the dipping step in the silver nitrate solution may be performed immediately after the dipping step in the acid and before drying or alcohol substitution.

The method for partially protonating the structure of the present embodiment is not particularly limited, but it is preferably protonated by immersing it in acetic acid, hydrochloric acid, or nitric acid adjusted to a predetermined concentration using alcohol. , More preferably acetic acid adjusted to a predetermined concentration. A SUS reactor can be used for protonation with acetic acid.
The antibacterial sheet-like structure of the present embodiment containing the protonated CMC may be used as it is after drying, but it is preferably heat-treated at a temperature of 50 ° C. or higher for 1 hour or longer, more preferably 80 to 80 to It is a heat treatment of 3 hours or more at a temperature of 120 ° C., and more preferably a heat treatment of 3 hours or more at a temperature of 100 to 120 ° C. By performing the heat treatment, the orientation of the molecule is optimized, and the strength can be further increased by increasing the intramolecular hydrogen bond. Examples of the heat treatment method include hot air treatment, dry heat treatment, wet heat treatment, and vacuum heat treatment. Hot air treatment is preferable for efficient treatment, but the treatment is not particularly limited thereto.

The method for introducing silver-containing particles into the structure of the present embodiment is not particularly limited, but is immersed in a silver nitrate solution adjusted to a predetermined concentration using an alcohol aqueous solution, and then the silver nitrate solution is drained and then chloride. It is preferable to precipitate silver-containing particles on the fiber surface by immersing in an aqueous solution of a halide-containing alcohol such as sodium. At this time, if the silver nitrate solution contains a large amount of water, the reaction rate of silver exchange is too fast and reaction unevenness occurs. Therefore, the water content in the silver nitrate solution is preferably 10% by weight or less. More preferably, the silver nitrate solution does not contain water. Furthermore, if unreacted silver nitrate remains in the solution, it reacts with sodium chloride to generate suspended particles of silver chloride in the system. Therefore, the solution is once removed before being immersed in the halide-containing alcohol aqueous solution. Is preferable. According to this method, silver-containing particles can be precipitated on the fiber surface layer. Further, the treatment with the halide-containing alcohol solution is preferably 1 hour or more at room temperature in order to completely atomize all the silver.

The structure of the present embodiment is characterized in that it gels when wet. By gelling when wet, the silver-containing particles adhering to the fiber surface are buried in the gel, making it difficult for them to flow out. In addition to having a high amount of liquid absorption, it also has high adhesion to the skin, making it easier to follow the movement of the skin. Furthermore, the gelation softens the texture and reduces the effect on the skin.
On the other hand, the gelled structure gradually dissolves to diffuse the silver-containing particles on the surface of the structure into the wound, that is, the silver-containing particles can be slowly released. Antibacterial properties are exhibited as the silver-containing particles in the wound diffuse, and the wound infection can be suppressed and the wound healing can be promoted.

Hereinafter, a method for measuring the physical property values of the antibacterial sheet-like structure used in Examples and Comparative Examples will be described.
1. 1. Measurement of average degree of substitution (DS) (i) Acidity, alkalinity About 1 g of the sample (anhydride) is precisely weighed in a 300 mL Erlenmeyer flask, and about 200 mL of water is added to dissolve it. Add 5 mL of 0.05 mol / L sulfuric acid with a pipette, boil for 10 minutes, cool, add a phenolphthalein indicator, and titrate with 0.1 mol / L potassium hydroxide (SmL). At the same time, a blank test was performed (XmL), and the following formula (1):
Alkaliity = {(XS) x f} / weight of sample anhydride (g). .. .. Equation (1)
Calculated by {in the formula, f: 0.1 mol / L potassium hydroxide titer}.
Here, when the value of {(XS) × f} is (−), the alkalinity is read as the acidity.

(Ii) Average degree of substitution (DS)
A sample (anhydride) of 0.5 to 0.7 g is precisely weighed, wrapped in filter paper, and incinerated in a porcelain crucible. After cooling, transfer this to a 500 mL beaker, add about 250 mL of water and 35 mL of 0.05 mol / L sulfuric acid with a pipette, and simmer for 30 minutes. This is cooled, a phenolphthalein indicator is added, and the excess acid is back titrated with 0.1 mol / L potassium hydroxide to formulate the following formula (2):
Y = (a × f－b × f1) / sample anhydride weight (g) -alkali (or + acidity). .. .. Equation (2)
{In the formula, Y: amount of 0.05 mol / L sulfuric acid consumed in 1 g of sample (mL), a: amount of 0.05 mol / L sulfuric acid used (mL), f: 0.05 Molar / L sulfuric acid titer, b: 0.1 molar / L potassium hydroxide titration (mL), f1: 0.1 molar / L potassium hydroxide titer}, and the following formula (3):
Substitution = (162 × Y) / (10000-80 × Y). .. .. Equation (3)
{In the equation, Y is the same as that defined in equation (2). }, The degree of substitution is calculated, and the average value (N = 3 or more) is used as the average degree of substitution.

2. Degree of Protonation Cut the ^{CMC structure into areas of 1 cm 2 or larger.} After that, it is set in an FT-IR (ATR) device and surface analysis is performed. After that, ATR correction, baseline correction, and standardization are performed, ^{the peak height at a wavelength of 1590 cm -1} is measured, and the ratio of the peak height before and after protonation is calculated from the following equation (4):
Degree of protonation (%) = (AB) / A × 100. .. .. Equation (4)
{In the formula, A: ( ^{peak height of 1590 cm -1} of the sample before protonation), B: (peak height ^{of 1590 cm -1 of the sample after protonation).} } To calculate the degree of protonation. The sample before protonation can be prepared by preparing an equivalent sample separately or by treating the sample with an aqueous sodium hydroxide solution.

3. 3. Silver content (% by weight)
Weigh 0.2 to 0.3 g of the sample (anhydrous) precisely, and add 20 mL of 0.1 mol / L sodium hydroxide aqueous solution, 10 mL of 23% ammonia aqueous solution, and 50 mL of water to dissolve. This is made up to 100 mL with water, and the solution diluted 100 times with water is used as a sample solution, and the silver ion concentration in the sample is identified according to the JIS K0101 and JIS K0102 tests certified by ISO17025. Using the sample weight and the silver ion concentration in the sample solution, the silver content in the sample is determined by the following formula (5):
Silver content (% by weight) = D / (C × 10). .. .. Equation (5)
{In the formula, C: sample weight (g), D: silver ion concentration (ppm)}.

4. Liquid absorption (g / 100 cm ² )
The amount of liquid absorbed is measured according to EN13726-1 regarding the absorption capacity when freely expanded. Specifically, the sample is cut into 5 cm × 5 cm and placed in a petri dish. Then, 40 times the weight of the sample, the pseudo-exudate (described in EN13726-1) is heated to 37 ° C., added, and allowed to stand in a thermostat at 37 ° C. for 30 minutes. After that, from the weight before and after incubation, the following formula (7):
Liquid absorption (g / 100 cm ² ) = (FE) x 4. .. .. Equation (7)
{In the formula, E: mass before liquid absorption (g), F: weight after incubation for 30 minutes (g)}.

5. Strength The sample is cut into 5 cm x 5 cm pieces and placed in a petri dish. Then, 40 times the weight of the sample, a pseudo-exudate (described in EN13726-1) is added, and the mixture is allowed to stand at 37 ° C. for 30 minutes. Take out the sample, pinch it with tweezers, and evaluate the strength according to the following evaluation criteria.
×: Cannot keep shape △: Can keep shape but difficult to grasp 〇: Holds shape and can be grasped, but collapses when pulled strongly ◎: For tension with some strength Can withstand

6. Antibacterial properties Antibacterial properties are evaluated based on the antibacterial activity value measured by the bacterial solution absorption method using Staphylococcus aureus in accordance with JIS L 1902. Comparative Example 1 is used as a control sample. In addition to the evaluation described in JIS L 1902 after 18 hours of culturing, the antibacterial activity value after 3 hours of culturing is also confirmed in order to evaluate the initial antibacterial property.

7. Antibacterial property after long-term immersion The evaluation is based on the antibacterial activity value measured by the bacterial solution absorption method using Staphylococcus aureus in accordance with JIS L 1902. Comparative Example 1 is used as a control sample. After preparing the test piece according to JIS L 1902, the test piece is placed in a petri dish. Then, 40 times the weight of the test piece is added to the pseudo-exudate (described in EN13726-1) after heating to 37 ° C., and the mixture is allowed to stand in a thermostat at 37 ° C. for 24 hours. Then, the swollen test piece is taken out, transferred to another petri dish, the same amount of pseudo-exudate is added again, and the mixture is allowed to stand in a thermostat at 37 ° C. for 24 hours. The test piece obtained by performing this operation 5 times is inoculated with the test inoculated bacterial solution, and the antibacterial activity value after 18 hours of culturing is confirmed according to JIS L 1902.

8. Average particle size of silver-containing particles A sample was observed with a scanning electron microscope (manufactured by Hitachi High-Tech Fielding Corporation, TM4000) at a magnification of 5000 times, and 10 particles existing on the fiber surface were randomly selected to correspond to the circumscribing circles of each. Measure the diameter. Let the average value of these be the average particle size (μm).

9. Particle distribution of silver-containing particles (uniform distribution)
With a scanning electron microscope (TM4000, manufactured by Hitachi High-Tech Fielding Corporation), the range in which the sample cross section is divided into 5 parts in the thickness direction of the sample is observed at a magnification of 1000 times, and the number of particles per ^{1000 μm 2 is measured.} When the coefficient of variation of the number of these particles is 0.5 or less, it is assumed that the particles in the structure are uniformly distributed in the thickness direction in the structure.

10. Metsuke (g / m ² )
In a mass test per unit area according to JIS-L1913, a test piece was taken from a sample using a punching blade having a diameter of 6 cm, and the basis weight was measured.

11. Thickness (mm)
In a thickness test conforming to JIS-L1096, the thickness was measured with a load of 1.96 kPa.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

[Comparative Example 1]
1 kg of regenerated cellulose continuous long fiber non-woven fabric (cuprammonium rayon non-woven fabric) (width 20 cm, grain 80 g / m ² , thickness 0.5 mm, density 0.154 g / m ³ ) is placed in a reaction vessel, and then an aqueous ethanol solution containing sodium hydroxide is placed. After adding (water: 8750 g, ethanol 8750 g, NaOH: 1625 g), the mixture was stirred at 35 ° C. for 30 minutes. Next, after draining the reagent in the reaction vessel, an aqueous ethanol solution containing sodium monochloroacetate (3000 g of water, 9600 g of ethanol, 1225 g of sodium monochloroacetate) was added, and the mixture was stirred at 50 ° C. for 3 hours. Then, after adjusting the pH to 6.0 to 8.0 with an acetic acid-containing ethanol aqueous solution (acetic acid: 375 g, distilled water: 3750 g, ethanol: 8750 g), once with a 70 wt% ethanol aqueous solution of 13750 g and once with a 90 wt% ethanol aqueous solution of 12500 g. It was washed and subjected to alcohol substitution twice with 12500 g of 100 wt% ethanol. This was dried to obtain CMC-Na.
The various evaluation results of this sample are shown in Table 1 below.

[Comparative Example 2]
Of the CMC-Na prepared in Comparative Example 1, 500 g was immersed in 7500 g (40 wt%) of an acetic acid-containing ethanol solution, stirred for 1 hour, and then washed once with 7500 g of a 70 wt% ethanol aqueous solution and once with 7500 g of a 90 wt% ethanol aqueous solution. Then, alcohol was replaced twice with 7500 g of 100 wt% ethanol, dried, and further heat-treated at 105 ° C. for 6 hours with a hot air dryer to obtain CMC-Na + CMC-H.
The various evaluation results of this sample are shown in Table 1 below.

[Comparative Example 3]
Various types of silver chloride powder (CMC-Na + AgCl powder) in which the silver content in the sample is 1.5% by sprinkling silver chloride powder 0.02 times the sample weight on the surface of the sample prepared in Comparative Example 1 before various evaluations. The evaluation results are shown in Table 1 below.

[Comparative Example 4]
Silver chloride powder was sprinkled 0.02 times the sample weight on the surface of the sample prepared in Comparative Example 2 before various evaluations to make the silver content in the sample 1.5% (CMC-Na + CMC-H + AgCl powder). The various evaluation results of are shown in Table 1 below.

[Comparative Example 5]
100 g of the sample prepared in Comparative Example 1 was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 2.5 g, water 5 g, ethanol 1495 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC-Ag.
The various evaluation results of this sample are shown in Table 1 below.

[Comparative Example 6]
100 g of the sample prepared in Comparative Example 2 was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 2.5 g, water 5 g, ethanol 1495 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC-Ag.
The various evaluation results of this sample are shown in Table 1 below.

[Comparative Example 7]
100 g of regenerated cellulose continuous long fiber non-woven fabric (cuprammonium rayon non-woven fabric) (width 20 cm, grain 80 g / m ² , thickness 0.5 mm, density 0.154 g / m ³ ) is placed in a 100 g reaction vessel, and then an aqueous ethanol solution containing sodium hydroxide is placed. After adding (water: 875 g, ethanol 875 g, NaOH: 163 g), the mixture was stirred at 35 ° C. for 30 minutes. Next, after draining the reagent in the reaction vessel, an aqueous ethanol solution containing sodium monochloroacetate (300 g of water, 960 g of ethanol, 230 g of sodium monochloroacetate) was added, and the mixture was stirred at 55 ° C. for 10 hours. Then, after adjusting the pH to 6.0 to 8.0 with an acetic acid-containing ethanol aqueous solution (acetic acid: 37.5 g, distilled water: 375 g, ethanol: 875 g), once with 1375 g of a 70 wt% ethanol aqueous solution, with 1250 g of a 90 wt% ethanol aqueous solution. It was washed once and replaced with alcohol twice with 1250 g of 100 wt% ethanol. After drying this, an aqueous solution of silver nitrate-containing ethanol (2.5 g of silver nitrate, 5 g of water, 1495 g of ethanol) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 1 below.

[Comparative Example 8]
100 g of regenerated cellulose continuous long fiber non-woven fabric (cuprammonium rayon non-woven fabric) (width 20 cm, grain 80 g / m ² , thickness 0.5 mm, density 0.154 g / m ³ ) is placed in a 100 g reaction vessel, and then an aqueous ethanol solution containing sodium hydroxide is placed. After adding (water: 875 g, ethanol 875 g, NaOH: 163 g), the mixture was stirred at 35 ° C. for 30 minutes. Next, after draining the reagent in the reaction vessel, an aqueous ethanol solution containing sodium monochloroacetate (300 g of water, 960 g of ethanol, 40 g of sodium monochloroacetate) was added, and the mixture was stirred at 45 ° C. for 1 hour. Then, after adjusting the pH to 6.0 to 8.0 with an acetic acid-containing ethanol aqueous solution (acetic acid: 37.5 g, distilled water: 375 g, ethanol: 875 g), once with 1375 g of a 70 wt% ethanol aqueous solution, with 1250 g of a 90 wt% ethanol aqueous solution. It was washed once and replaced with alcohol twice with 1250 g of 100 wt% ethanol. After drying this, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 5 g, water 10 g, ethanol 1490 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 1 below.

[Comparative Example 9]
100 g of the sample prepared in Comparative Example 1 was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (2.5 g of silver nitrate, 5 g of water, 1495 g of ethanol) was added, and the mixture was stirred at 35 ° C. for 1 hour. Then, the reagent in the reaction vessel was not drained, an aqueous sodium chloride solution (40 g of sodium chloride, 450 g of water) was added to the reaction vessel, and the mixture was further stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 1 below.
In Comparative Example 9, in the particle distribution of the silver-containing particles, the coefficient of variation of the number of particles was 0.5 or less, and the particles in the structure were not uniformly distributed in the thickness direction in the structure.

[Example 1]
100 g of the sample prepared in Comparative Example 1 was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 2.5 g, water 5 g, ethanol 1495 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 2 below.

[Example 2]
100 g of the sample prepared in Comparative Example 2 was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 2.5 g, water 5 g, ethanol 1495 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 2 below.

[Example 3]
100 g of regenerated cellulose continuous long fiber non-woven fabric (cuprammonium rayon non-woven fabric) (width 20 cm, grain 80 g / m ² , thickness 0.5 mm, density 0.154 g / m ³ ) is placed in a 100 g reaction vessel, and then an aqueous ethanol solution containing sodium hydroxide is placed. After adding (water: 875 g, ethanol 875 g, NaOH: 163 g), the mixture was stirred at 35 ° C. for 30 minutes. Next, after draining the reagent in the reaction vessel, an aqueous ethanol solution containing sodium monochloroacetate (300 g of water, 960 g of ethanol, 80 g of sodium monochloroacetate) was added, and the mixture was stirred at 45 ° C. for 3 hours. Then, after adjusting the pH to 6.0 to 8.0 with an acetic acid-containing ethanol aqueous solution (acetic acid: 37.5 g, distilled water: 375 g, ethanol: 875 g), once with 1375 g of a 70 wt% ethanol aqueous solution, with 1250 g of a 90 wt% ethanol aqueous solution. It was washed once and replaced with alcohol twice with 1250 g of 100 wt% ethanol. After drying this, an aqueous solution of silver nitrate-containing ethanol (2.5 g of silver nitrate, 5 g of water, 1495 g of ethanol) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 2 below.

[Example 4]
100 g of regenerated cellulose continuous long fiber non-woven fabric (cuprammonium rayon non-woven fabric) (width 20 cm, grain 80 g / m ² , thickness 0.5 mm, density 0.154 g / m ³ ) is placed in a 100 g reaction vessel, and then an aqueous ethanol solution containing sodium hydroxide is placed. After adding (water: 875 g, ethanol 875 g, NaOH: 163 g), the mixture was stirred at 35 ° C. for 30 minutes. Next, after draining the reagent in the reaction vessel, an aqueous ethanol solution containing sodium monochloroacetate (300 g of water, 960 g of ethanol, 180 g of sodium monochloroacetate) was added, and the mixture was stirred at 55 ° C. for 5 hours. Then, after adjusting the pH to 6.0 to 8.0 with an acetic acid-containing ethanol aqueous solution (acetic acid: 37.5 g, distilled water: 375 g, ethanol: 875 g), once with 1375 g of a 70 wt% ethanol aqueous solution, with 1250 g of a 90 wt% ethanol aqueous solution. It was washed once and replaced with alcohol twice with 1250 g of 100 wt% ethanol. After drying this, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 5 g, water 10 g, ethanol 1490 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 2 below.

[Example 5]
100 g of regenerated cellulose continuous long fiber non-woven fabric (cuprammonium rayon non-woven fabric) (width 20 cm, grain 80 g / m ² , thickness 0.5 mm, density 0.154 g / m ³ ) is placed in a 100 g reaction vessel, and then an aqueous ethanol solution containing sodium hydroxide is placed. After adding (water: 875 g, ethanol 875 g, NaOH: 163 g), the mixture was stirred at 35 ° C. for 30 minutes. Next, after draining the reagent in the reaction vessel, an aqueous ethanol solution containing sodium monochloroacetate (300 g of water, 960 g of ethanol, 180 g of sodium monochloroacetate) was added, and the mixture was stirred at 55 ° C. for 5 hours. Then, after adjusting the pH to 6.0 to 8.0 with an acetic acid-containing ethanol aqueous solution (acetic acid: 37.5 g, distilled water: 375 g, ethanol: 875 g), once with 1375 g of a 70 wt% ethanol aqueous solution, with 1250 g of a 90 wt% ethanol aqueous solution. It was washed once and replaced with alcohol twice with 1250 g of 100 wt% ethanol. After drying this, it is immersed in 1250 g (90 wt%) of an acetic acid-containing ethanol solution, stirred for 1 hour, washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and with 1250 g of 100 wt% ethanol. Alcohol was replaced twice, dried, and further heat-treated at 105 ° C. for 6 hours with a hot air dryer to obtain CMC-Na + CMC-H. After drying this, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 5 g, water 10 g, ethanol 1490 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 2 below.

[Example 6]
100 g of the sample prepared in Comparative Example 1 was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (silver nitrate 0.5 g, water 5 g, ethanol 1495 g) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 2 below.

[Example 7]
100 g of the sample prepared in Comparative Example 1 was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (8.0 g of silver nitrate, 5 g of water, 1495 g of ethanol) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
The various evaluation results of this sample are shown in Table 2 below.

[Example 8]
1.5 kg of regenerated cellulose filament (cuprammonium rayon, fiber length 51 mm, fineness 2.2 T) was placed in a reaction vessel, and then an aqueous ethanol solution containing sodium hydroxide (water: 8750 g, ethanol 8750 g, NaOH: 1625 g) was added. Then, the mixture was stirred at 35 ° C. for 30 minutes. Next, after draining the reagent in the reaction vessel, an aqueous ethanol solution containing sodium monochloroacetate (3000 g of water, 9600 g of ethanol, 1225 g of sodium monochloroacetate) was added, and the mixture was stirred at 50 ° C. for 3 hours. Then, after adjusting the pH to 6.0 to 8.0 with an acetic acid-containing ethanol aqueous solution (acetic acid: 375 g, distilled water: 3750 g, ethanol: 8750 g), once with a 70 wt% ethanol aqueous solution of 13750 g and once with a 90 wt% ethanol aqueous solution of 12500 g. It was washed and subjected to alcohol substitution twice with 12500 g of 100 wt% ethanol. This was dried to obtain CMC-Na.
Of these, 100 g was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (2.5 g of silver nitrate, 5 g of water, 1495 g of ethanol) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
Table 2 below shows various evaluation results of the sample made into a non-woven fabric by needle punching.

[Example 9]
Of the CMC-Na prepared in Example 8, 500 g was immersed in 7500 g (40 wt%) of an acetic acid-containing ethanol solution, stirred for 1 hour, and then washed once with 7500 g of a 70 wt% ethanol aqueous solution and once with 7500 g of a 90 wt% ethanol aqueous solution. Then, alcohol was replaced twice with 7500 g of 100 wt% ethanol, dried, and further heat-treated at 105 ° C. for 6 hours with a hot air dryer to obtain CMC-Na + CMC-H.
Of these, 100 g was placed in a reaction vessel, an aqueous solution of silver nitrate-containing ethanol (2.5 g of silver nitrate, 5 g of water, 1495 g of ethanol) was added, and the mixture was stirred at 35 ° C. for 2 hours. Next, after draining the solution in the reaction vessel, it was immersed in an aqueous ethanol solution containing sodium chloride (sodium chloride 40 g, water 450 g, ethanol 1150 g) and stirred for 1 hour. Then, it was washed once with 1375 g of a 70 wt% ethanol aqueous solution and once with 1250 g of a 90 wt% ethanol aqueous solution, and alcohol was replaced twice with 1250 g of 100 wt% ethanol. This was dried to obtain CMC / Ag.
Table 2 below shows various evaluation results of the sample made into a non-woven fabric by needle punching.

In Comparative Example 3 and Comparative Example 4 in which silver chloride powder was simply sprinkled on the CMC, Comparative Example 7 having a substitution degree of more than 1, and Comparative Example 8 having a substitution degree of less than 0.1, the antibacterial activity value after immersion was high. It was as small as 1 or less, suggesting that the antibacterial action after long-term application was weakened.
In Comparative Examples 5 and 6 in which silver was present as an ion inside the CMC, the antibacterial activity value at 3 hours was as small as 1 or less, suggesting that the initial antibacterial action was weak.

When the antibacterial sheet-like structure of the present invention is used as a wound dressing, the silver-containing particles can be gradually released and retained in the wound at a high concentration by the arrangement of the silver-containing particles on the fiber surface layer and the gelling action of CMC. Therefore, the antibacterial property can be maintained for a long time, and the healing of the wound can be promoted by keeping the wound in a clean state.

Claims

An antibacterial sheet-like structure containing carboxymethyl cellulose (CMC) fibers in which silver-containing particles are present on the fiber surface, and the following (1) to (4):
(1) The average degree of substitution of the CMC is 0.1 or more and 1.0 or less;
(2) The amount of Ag with respect to the weight of the CMC fiber is 0.01% by weight or more and 5.0% by weight or less;
(3) The average particle size of the silver-containing particles is 0.01 μm or more and 5 μm or less; and (4) the silver-containing particles are uniformly distributed in the thickness direction of the antibacterial sheet-like structure;
An antibacterial sheet-like structure characterized by.
The antibacterial sheet-like structure according to claim 1, wherein the silver-containing particles are particles containing at least one selected from the group consisting of metallic silver, silver nanoparticles, silver halide, and silver sulfaziazine.
The antibacterial sheet-like structure according to claim 1 or 2, wherein the amount of liquid absorbed when impregnated with the pseudo-exudate is 5 g / 100 cm 2 or more and 70 g / 100 cm 2 or less.
The antibacterial sheet-like structure according to any one of claims 1 to 3, wherein the counter cation of the CMC is at least one selected from the group consisting of sodium ions or protons.
The antibacterial sheet-like structure according to any one of claims 1 to 4, wherein 5% or more and 80% or less of the carboxymethyl group of the CMC is protonated.
The antibacterial sheet-like structure according to any one of claims 1 to 5, wherein the CMC fiber is a fiber derived from cuprammonium rayon.
The antibacterial sheet-like structure according to any one of claims 1 to 6, wherein the CMC fiber is a continuous length fiber.
The antibacterial sheet-like structure according to any one of claims 1 to 7, wherein the number average fiber diameter of the CMC fibers is 1 μm or more and 100 μm or less.
The antibacterial sheet-like structure according to any one of claims 1 to 8, which is in the form of a woven fabric, a knitted fabric, or a non-woven fabric.
The antibacterial sheet-like structure according to any one of claims 1 to 9, which has a basis weight of 10 g / m 2 or more and 200 g / m 2 or less.
The antibacterial sheet-like structure according to any one of claims 1 to 10, which has a thickness of 0.03 mm or more and 2.0 mm or less.
The antibacterial sheet shape according to any one of claims 1 to 11, wherein the coefficient of variation of the number of silver-containing particles per 1000 μm 2 in each of the ranges divided into five in the thickness direction in the structure is 0.5 or less. Structure.
An antibacterial medical material containing the antibacterial sheet-like structure according to any one of claims 1 to 12.
An antibacterial wound dressing containing the antibacterial sheet-like structure according to any one of claims 1 to 12.