Metal film piece forming cloth and producing method thereof

Abstract

To provide a metal film piece forming cloth capable of, even when a metallic film is formed into clothes, building materials, and other various kinds of fabrics, obtaining excellent antibacterial effect, without disturbing designability and texture, moreover, capable of simply and cheaply producing the same and a producing method thereof.SOLUTION: By immersing a fabric in a metal film piece forming composition containing a metal precursor liquid having a reaction product of at least one species selected from a group consisting of metal complexes and metal salts and at least one species selected from ammonia and amines, and an organic reducing agent, and then drying the fabric, a metal film piece 3 is formed in a dispersed state on the surface of each filament constituting at least the cloth 2, and a metal film piece forming cloth 1 having the average color difference measured at nine evenly spaced points in a 3x3 grid within a 25 mm square of between 1.3 and 6.5.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a metal film piece-formed fabric obtained by providing a metal in a dispersed state to a woven or nonwoven fabric, and a method for producing the same. [Background technology]

[0002] In general, deodorizing fiber sheets and bactericidal filters are known that are designed to exhibit deodorizing or sterilizing effects by forming a film of a metal such as Cu on a fiber filter (see, for example, Patent Documents 1 to 3).

[0003] Conventionally, a method for forming a metal film on such sheets or filters has been to immerse them in a special solution and then dry them, so that the film has good electrical and thermal conductivity (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 52-44458 [Patent Document 2] Japanese Patent Application Publication No. 58-8530 [Patent Document 3] JP 2006-14965 A [Patent Document 4] Patent Publication No. 2021-70873 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of the above-mentioned conventional film-forming method, when the metal-filmed bactericidal sheet is used for clothing, building materials, or various other fabrics, the metallic color becomes too strong, resulting in a disadvantage in that the design is reduced.

[0006] In addition, as in the above-mentioned conventional film-forming method, when the film is formed so that the electrical conductivity and thermal conductivity are good, electrons can freely move in the wide range of the metal film on the surface of the substrate. That is, in the metal film formed by the above-mentioned conventional film-forming method, electrons are released from the surface of metal and metal oxide, react with oxygen in the air to generate superoxide, and the superoxide reacts with moisture in the air to generate active oxygen, and the active oxygen exerts antibacterial properties. However, since the entire metal-filmed bactericidal sheet is a conductor, if a potential difference occurs at a specific part of the metal film due to an external factor, the movement of free electrons is restricted, and the electron emission is easily biased, making it difficult for the entire metal film to exert antibacterial effects uniformly. In particular, when this metal-filmed bactericidal sheet is used for clothing, building materials, and other various fabrics, only a small amount of metal film pieces are attached, so the effect is significant, and excellent antibacterial properties cannot be obtained.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a metal film piece-formed fabric and a manufacturing method thereof that can provide good antibacterial effects without impairing the design or texture, even when a metal film is applied to clothing, building materials, and various other fabrics, and that can be manufactured simply and inexpensively. [Means for solving the problem]

[0008] The metal film piece-forming fabric of the present invention for solving the above problems is formed by immersing the fabric in a metal film piece-forming composition containing a metal precursor liquid having a reaction product of at least one selected from the group consisting of metal complexes and metal salts with at least one selected from ammonia and amines, and an organic reducing agent, and then drying the fabric, forming metal film pieces in a dispersed state at least on the surface of each filament constituting the fabric, and the average color difference measured at nine equally spaced points in three vertical and three horizontal rows within a 25 mm square area is 1.3 to 6.5. The average color difference may also be 1.3 to 3.0.

[0009] The metal film piece-forming cloth may have an electrical resistance of 100 MΩ or more on the plane and between two points on the front and back.

[0010] The above-mentioned metal film piece-formed cloth was cut into pieces of 20 mm × 20 mm, sterilized, and then placed in a sterilized petri dish. NBRC3972 E. coli was inoculated with 9 × 10 5 ~3×10 6 0.1 ml of a test bacterial solution adjusted to a concentration of cfu / ml is dropped, and the solution is cultured at 35±1°C for 48 hours. After thorough washing using 9.9 ml of SCDLP medium, the solution is serially diluted to 1:10,000 with diluted water, and each diluted bacterial solution is cultured at 35±1°C for 24 hours using the agar plate culture method. The antibacterial activity value may be 2.0 or more.

[0011] The metal of the metal film piece forming cloth may be Cu.

[0012] In the above metal film piece forming fabric, the fabric may be made of natural or synthetic fibers.

[0013] The method for producing a metal film flake-formed fabric of the present invention for solving the above problems includes a step of immersing a fabric in a metal film flake-formed composition containing a metal precursor liquid having a reaction product of at least one selected from the group consisting of metal complexes and metal salts with at least one selected from ammonia and amines, and an organic reducing agent, and a step of drying the fabric after the immersion, thereby forming metal film flakes in a dispersed state on at least the surface of each filament constituting the fabric, and by adjusting the immersion time and immersion temperature, the average color difference measured at nine equally spaced points in three vertical and three horizontal rows in a 25 mm square area is 1.3 to 6.5. The average color difference may also be 1.3 to 3.0.

[0014] The manufacturing method for the above-mentioned metal film-formed fabric involves adjusting the immersion time and immersion temperature to form metal film pieces in a dispersed state at least on the surface of each filament constituting the fabric so that the electrical resistance between two points on a plane is 100 MΩ or more.

[0015] The method for producing the metal film-formed fabric is as follows: cut the fabric into pieces of 20 mm × 20 mm, sterilize the pieces, place them in a sterilized petri dish, and infuse NBRC3972 E. coli at 9 × 10 with phosphate buffer. 5 ~3×10 6 0.1 ml of the test bacteria solution adjusted to a concentration of cfu / ml is dropped, and after culturing at 35±1°C for 48 hours, the solution is thoroughly washed out using 9.9 ml of SCDLP medium, and then serially diluted to 1:10,000 with diluted water. Each diluted solution is cultured on an agar plate at 35±1°C for 24 hours. The immersion time and temperature may be adjusted so that the antibacterial activity value is 2.0 or more.

[0016] [Metal precursor liquid] The metal precursor liquid is obtained by reacting at least one selected from the group consisting of a metal complex and a metal salt with at least one selected from ammonia and an amine in a mixed liquid of at least one selected from the group consisting of a metal complex and a metal salt, at least one selected from ammonia and an amine, and a solvent.

[0017] [At least one selected from the group consisting of metal complexes and metal salts] The at least one selected from the group consisting of the above metal complexes and metal salts may be only one or more types of metal complexes, only one or more types of metal salts, or a mixture containing both one or more types of metal complexes and one or more types of metal salts.

[0018] The metal complex is preferably a reaction product of one or more compounds for forming a metal complex selected from compounds having a partial structure of a NH3 ligand, an RNH2 ligand (R represents an alkylene group), an OH2 ligand, and a ligand derived from a diamine such as ethylenediamine or hexamethylenediamine, which can generate a metal complex, and a metal ion. The metal complex may be a metal complex previously generated by the above reaction. As the metal in the metal complex, a metal according to the purpose of the metal film to be formed may be used. Examples of the metal include silver (Ag), copper (Cu), lithium (Li), nickel (Ni), manganese (Mn), zinc (Zn), and cobalt (Co). Specific examples of the metal complex include ethylenediaminetetraacetate copper, tetraammine copper, and the like, which contain copper (Cu) as a metal.

[0019] The metal salt is a metal compound having a function of dissociating in a solvent containing water to become metal ions and forming a metal complex. The metal salt refers to a metal salt that is soluble in water at 25°C. Soluble in water at 25°C means that the solubility in water at 25°C is 0.1% by mass or more, and the solubility is preferably 1% by mass or more. When the metal salt is soluble in water, the metal salt dissociates in a solvent containing water to become metal ions, and the metal ions react with amines contained in the solvent to obtain a metal complex. Furthermore, when a compound for forming a complex described later is optionally contained in the solvent, the metal ions may react with the compound for forming a complex to form a metal complex.

[0020] [At least one selected from ammonia and amines] The at least one selected from the above ammonia and amine may be only one or more types of ammonia, may be only one or more types of amine, or may be a mixture containing both one or more types of ammonia and one or more types of amine. These may be included as salt compounds. The amines include primary amines, secondary amines, and tertiary amines. Specific examples of amines include alkylamines. Instead of amines or in addition to amines, ammonia may be included. As ammonia, various substances having basicity similar to amines can be used.

[0021] [solvent] The solvent is not particularly limited as long as it can dissolve at least one selected from the group consisting of the above-mentioned metal complexes and metal salts, and at least one selected from the above-mentioned ammonia and amines, and for example, an aqueous solvent such as water or a mixture of water and alcohol can be used. It is preferable that the water contains a small amount of impurities, particularly ions other than metal ions, and from this viewpoint, it is preferable to use purified water, ion-exchanged water, pure water, etc. Examples of alcohol include monohydric alcohols having 1 to 10 carbon atoms, such as methanol, ethanol, isopropanol, n-propanol, isobutanol, and n-butanol, and polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, and glycerin.

[0022] From the viewpoint of solubility and handling, the aqueous solvent is preferably water or a mixture of water and a monohydric alcohol having 1 to 5 carbon atoms, more preferably water or a mixture of water and an alcohol selected from methanol, ethanol and propanol, and even more preferably water. When using a mixture of water and alcohol as a solvent, the mixing ratio is appropriately selected depending on the purpose. When using a mixture of water and alcohol as a solvent, the content of alcohol in the total amount of the mixture of water and alcohol is preferably 1% by mass to 60% by mass.

[0023] [Preparation of metal precursor liquid] The metal precursor liquid can be prepared by adding at least one selected from the group consisting of the above-mentioned metal complexes and metal salts, and at least one selected from the above-mentioned ammonia and amines in a solvent, and thoroughly stirring and mixing the mixture.

[0024] Mixing may be performed at room temperature, or for the purpose of promoting dissolution, the solvent may be heated to 40° C. to 60° C. The stirring method is not particularly limited, and any known stirring method can be used, such as a method of putting the mixed solution into a container and stirring it using a rotor such as a magnetic stirrer, a method of stirring with a stirring device equipped with a rotary stirring blade such as a paddle, a method of putting the solution into a sealable container and stirring by shaking the container, and a method of irradiating with ultrasound.

[0025] A simple method is to use a stirring device equipped with a stirring blade. The rotation speed of the rotor can be 300 rpm (revolutions / minute: the same below) to 800 rpm, and preferably 400 rpm to 600 rpm. The stirring is preferably performed until the reaction between at least one selected from the group consisting of the above-mentioned metal complexes and metal salts and at least one selected from the above-mentioned ammonia and amines proceeds sufficiently, and when stirring is performed at room temperature using the above-mentioned stirring device equipped with a rotor, stirring is preferably performed for about 30 minutes to 90 minutes, and more preferably for about 50 minutes to 80 minutes. For example, when preparing a metal precursor liquid containing a copper complex, the metal precursor liquid that has been thoroughly stirred exhibits a blue color due to copper ions.

[0026] The above-mentioned metal precursor liquid may be prepared by applying a known molecular precursor method. In addition, the preparation of the metal precursor liquid can be performed by applying a known precursor method as described above, but from the viewpoint of obtaining a metal precursor with higher purity, it is preferable to include the following electrolysis step. That is, this electrolysis step is a step of storing an amine-containing electrolytic solution in each of the pair of electrolytic solution tanks in a reaction apparatus equipped with a pair of electrolytic solution tanks connected via a flow path equipped with a filter that does not allow metal ions to pass through but can allow hydrogen ions to pass through, and arranging a pair of metal electrodes at a position where at least a part of the electrodes contacts the electrolytic solution, and connecting the pair of electrodes via a DC power source, and applying a voltage between the pair of electrodes by a DC power source, and reacting the metal ions derived from the metal that is the electrode with the electrolytic solution in the electrolytic solution tank in which the electrode that becomes the anode is immersed to obtain a metal precursor liquid.

[0027] [Organic reducing agents] The organic reducing agent preferably includes at least one selected from compounds having a carboxy group. The organic reducing agent is preferably appropriately selected from organic carboxylic acid compounds having a carboxy group in the molecule and functioning as a reducing agent.

[0028] Examples of the organic reducing agent include at least one selected from ascorbic acid, citric acid, oxalic acid, formic acid, and 3,4,5-trihydroxybenzoic acid, and from the viewpoint of better formability of the metal film pieces, at least one selected from ascorbic acid, citric acid, and 3,4,5-trihydroxybenzoic acid is preferable, and at least one selected from ascorbic acid and citric acid is more preferable. One of the preferred aspects of the composition for forming metal film pieces is to include ascorbic acid as the organic reducing agent.

[0029] The organic reducing agent is preferably used as an aqueous solution. The water used to prepare the aqueous solution is preferably free of metal ions or has a metal ion concentration as low as possible from the viewpoint of uniformity of the obtained metal film, and therefore, the water used to prepare the aqueous solution is preferably purified water, ion-exchanged water, pure water, etc. In order to improve the solubility when dissolving the organic reducing agent in water, the water as the solvent may be heated to 30°C to 60°C, and preferably to 35°C to 45°C. The dissolution may be performed with stirring, and the stirring method can be appropriately applied in the same manner as the stirring method mentioned in the section on the method for preparing the solution of the metal complex described above. The content of the specific reducing agent in the aqueous solution of the organic reducing agent is preferably in the range of 10% by mass to 40% by mass, and more preferably in the range of 10% by mass to 30% by mass. When the content of the organic reducing agent relative to the total amount of the aqueous solution is 10% by mass or more, the aqueous solution contains a sufficient amount of organic reducing agent for the reaction, and when the content is 40% by mass or less, the stability of the aqueous solution is improved.

[0030] [Preparation of composition for forming metal film pieces] The metal film piece forming composition is obtained by mixing the metal precursor liquid and the organic reducing agent, and the mixing ratio of the metal precursor liquid and the organic reducing agent is not particularly limited and can be appropriately selected according to the target metal. The metal ion contained in the metal precursor liquid can be 30 parts by mass to 400 parts by mass relative to 100 parts by mass of the organic reducing agent contained in the metal film piece forming composition. In particular, if the metal film piece forming composition obtained has good formability, it will deviate from the original purpose of obtaining good antibacterial results without impairing the design and texture, so from the viewpoint of not promoting the formability of the metal film piece too much, it is preferable that the metal ion contained in the metal precursor liquid is 30 parts by mass to 350 parts by mass relative to 100 parts by mass of the organic reducing agent, and more preferably that the metal ion contained in the metal precursor liquid is 30 parts by mass to 250 parts by mass relative to 100 parts by mass of the organic reducing agent.

[0031] The content of the metal precursor liquid in the preparation of the composition for forming metal film pieces can be controlled by adjusting the type and content of the metal complex when preparing the metal precursor liquid, or the type of electrolyte, the concentration of the electrolyte, the applied energy of the direct current, the application time, etc. in the electrolysis process when preparing the above-mentioned metal precursor liquid.

[0032] In general, it is difficult to measure the content of a specific metal compound relative to the total amount of the composition for forming metal film pieces. However, the physical properties of the metal film pieces formed by the composition for forming metal film pieces depend on the metal content in the composition for forming metal film pieces. From the viewpoint of forming stable metal film pieces, the metal content relative to the total amount of the composition for forming metal film pieces is preferably in the range of 0.5% by mass to 10% by mass, and more preferably in the range of 1% by mass to 8% by mass. When the metal content is in the above range, the structure of the metal film pieces formed by the composition for forming metal film pieces becomes more uniform, and stable metal film pieces can be formed.

[0033] The metal content in the composition for forming metal film pieces can be measured, for example, by the method described in "Basics of Coordination Chemistry: Werner Complexes and Organometallic Complexes" (KS Chemistry Specialist Book: Kodansha, 1989).

[0034] The content of the specific reducing agent in the composition for forming metal film pieces can be measured, for example, by the following method. First, the composition for forming metal film pieces is dried to prepare a powder. The obtained powder is analyzed using a thermogravimeter-differential thermal analyzer (TG-DTA) to measure the content of the specific reducing agent.

[0035] The pH of the composition for forming metal film pieces at room temperature (25° C.) is preferably 6 to 8, and more preferably in the neutral range of about pH 7.5. The pH can be measured with a known pH meter.

[0036] [cloth] The cloth may be either woven or nonwoven. In the case of woven, it may be a woven fabric for various architectural interior materials to be attached to the interior of walls and ceilings, or a mesh-like net to be used for screen doors. It may also be various woven fabrics such as curtains, carpets, mats, chairs, and clothing. In the case of nonwoven, it may be a nonwoven fabric to be attached to the interior of walls and ceilings, or a nonwoven fabric to be used for sliding doors, shoji screens, and light shades. The filaments of the fibers constituting the woven or nonwoven fabric may be inorganic fibers such as glass fibers, or organic fibers such as polyethylene such as PET, low-density polyethylene (LDPE), high-density polyethylene (HDPE), polycarbonate (PC), polyvinyl chloride (PVC), polystyrene, acrylic resins such as polymethyl methacrylate (PMMA), polyamides such as nylon 6, phenolic resins, melamine resins, urethane resins, and carbon fibers, or natural fibers such as silk, cotton, cellulose, and hemp. It may also be composed of a combination of these filaments. The fabric may be in the form of a raw material before processing, or may be a processed material that has already been processed to fit the chair.

[0037] [Production of metal film forming cloth] The metal film piece-formed fabric is manufactured by immersing the fabric in the metal film piece-formed composition and drying the fabric, so that metal film pieces are dispersed and formed on at least the surface of each filament constituting the fabric. In this case, the immersion time, immersion temperature, and number of immersions and drying are not particularly limited as long as the average color difference measured at 9 points equally spaced in 3 vertical and 3 horizontal rows within a 25 mm square area of ​​the completed metal film piece-formed fabric is 1.3 to 6.5. Batch tests are performed for the immersion time, immersion temperature, and number of immersions and drying, and the immersion time, immersion temperature, and the like that satisfy the relevant conditions can be adopted. In this case, the immersion time, immersion temperature, and the like that satisfy the relevant conditions can be adopted as long as the average color difference is 1.3 to 6.5, but are not particularly limited, and are preferably 1.3 to 3.0, more preferably 1.3 to 1.5. If the color difference is less than 1.3, sufficient antibacterial effect cannot be obtained. If the color difference is between 1.3 and 1.5, it can be used without any problem as the same color, and if it is between 1.3 and 3.0, it can be judged as the same color when viewed from a distance or depending on the color. If the color difference is higher than 1.3, the antibacterial effect increases, but if the color difference exceeds 3.0, there is no problem if the saturation and brightness are low, but if the saturation and brightness of the original fabric are high, it becomes clear that the fabric has been colored by the attachment of the metal film piece. Also, even if the color difference exceeds 3.0, the desired antibacterial effect is obtained with a color difference of 1.3 or more, so the effect is saturated and wasted. Therefore, if a stronger antibacterial effect is required, it is acceptable to attach the metal film piece up to a color difference of 6.5 or less. If the color difference is 6.5 or less, it can be kept within the range that can be accepted as the same color as a Class B tolerance in color management, and the electrical resistance between two points on the plane can be kept at 100MΩ or more.

[0038] In order to control the color difference when immersing the cloth in the above-mentioned metal film piece forming composition, it is preferable to mix the metal precursor liquid cooled to a low temperature with the organic reducing agent cooled to a low temperature to form a low-temperature metal film piece forming composition, and immerse the cloth in this low-temperature metal film piece forming composition. This is because if the temperature of the metal film piece forming composition is high during immersion, the reaction is promoted. For example, in the example described below, the metal film piece forming composition obtained by mixing the metal precursor liquid cooled to 2°C and the organic reducing agent cooled to 2°C for 20 minutes was 20°C. In this case, a color difference of 1.3 is obtained by immersion for about 1 hour, and the color difference can be controlled to the desired color difference range in less than 2 hours. Although this time varies slightly depending on the metal precursor liquid and organic reducing agent used, the color difference can be controlled in approximately the same time. In this case, the cooling is not particularly limited as long as the metal precursor liquid cooled to a low temperature and the organic reducing agent cooled to a low temperature do not freeze, and may be a general refrigeration temperature of 0 to 5°C or lower.

[0039] There is no particular upper limit to the immersion time, but if the immersion time exceeds 2 hours, the amount of attached metal film pieces will increase, and the antibacterial effect of the metal film-formed fabric will improve. However, if too many metal film pieces are attached, the color difference of the fabric will become too large, and the coloring due to the metal film pieces will be noticeable. At the same time, the metal film-formed fabric will become a conductor due to the attached metal film pieces, and if a potential is generated in a part of the metal film-formed fabric, the antibacterial effect will not be exerted in other parts. Therefore, the immersion time and immersion temperature for immersing the fabric in the composition for forming metal film pieces are preferably such that the electrical resistance between two points on the plane of the completed metal film-formed fabric is 100 MΩ or more. Considering these, the immersion time is from 1 to 2 hours, and there is no limit for longer than that as long as the electrical resistance is 100 MΩ or more, but from the viewpoint of productivity, it is better to set it to within 24 hours, preferably within 8 hours.

[0040] In addition, depending on the circumstances, immersion may be performed under a reduced pressure environment or a pressurized environment.

[0041] The drying after immersion can be performed by a conventional method such as natural drying, heat drying, or blow drying, which are generally performed. In the case of natural drying, it is sufficient to leave it at room temperature for a desired time. In the case of heat drying, a known heating means can be appropriately selected and applied. Examples of the heating method include a method of contacting a heating means such as a plate-shaped heater or a heat roll from the back side of the substrate, a method of passing through a heating zone such as an electric furnace, a method of irradiating energy rays such as infrared rays or microwaves, and a method of blowing hot air. There is no particular limit to the heating temperature during heat drying. Considering the drying efficiency and suppression of the influence on the substrate, the heating temperature can be in the range of 30°C or more and less than 100°C, and it is preferable to set it in the range of 30°C to 60°C. From the viewpoint of productivity, the drying time during heat drying can be in the range of several tens of seconds to several tens of minutes, but is not particularly limited, and may be several hours in cases where performance is exhibited depending on the drying time. In the case of blow drying, it may be blow drying by blowing air under the environmental atmosphere, or blow drying by blowing hot air as described above. These methods such as natural drying, heat drying, and air drying may be used in combination.

[0042] The amount of metal that constitutes the metal film piece by the metal film piece forming composition is not particularly limited, but in fact, when the metal film piece forming fabric is formed as an interior material, it will be used for a long period of time. However, on the other hand, if the amount of metal attached is large, the color difference becomes large, and it becomes obvious that the metal has been attached, which impairs the design. Therefore, it is most efficient for the metal film piece forming fabric to obtain the desired antibacterial effect and form the metal film with as little metal attachment as possible. Specifically, as described above, it is desirable that the average color difference measured at 9 points equally spaced in 3 vertical rows and 3 horizontal rows in a 25 mm square range is 1.3 to 6.5, preferably 1.3 to 3.0, more preferably 1.3 to 1.5, and the electrical resistance between two points on the plane is 100 MΩ or more, but such an amount of metal attachment can be easily met with a short immersion time of about 1 to 2 hours, so in the case of the composition for forming the metal film piece according to the embodiment described later, it can be achieved by simply immersing and drying once.

[0043] The dispersion state of the metal film pieces formed on the metal film piece-forming cloth can be confirmed by the electrical resistance between two points on the plane of the metal film piece-forming cloth being non-conductive at 100 MΩ or more, but ideally, it is preferable that the metal film pieces are formed in a uniformly dispersed state at least on each filament constituting the cloth from the surface to the inside of the cloth. When the cloth is immersed in the composition for forming metal film pieces, the composition for forming metal film pieces can be contacted evenly with the entire surface of each filament constituting the cloth from the surface to the inside of the cloth, so that the uniformly dispersed state described above can be easily obtained.

[0044] For the antibacterial effect, it is important that the free electrons of the metal molecules that make up the formed metal film pieces can move freely. However, if, as shown in Figure 2(a), electrical conductivity is ensured and the metal film b becomes a single conductor, as in metal film-formed fabric a in which the metal film b is formed over the entire fabric c, when part of the metal film-formed fabric a is placed in an environment that generates a potential difference, as shown in Figure 2(b), there is a concern that the movement of the free electrons e around the metal molecules d that make up the metal film b will be hindered, and the antibacterial effect will not be achieved. However, if the metal film pieces 3 are formed in a dispersed state on fabric 2, as in metal film piece-formed fabric 1 shown in Figure 1(a), the electrical conductivity is independent in the formation area of ​​each dispersed metal film piece 3, so the movement of the free electrons 32 around the metal molecules 31 that make up each metal film piece 3 is ensured. Therefore, as shown in FIG. 1(b), even if a part of the area of ​​the metal film piece-formed cloth 1 where the metal film piece 3 is formed is placed in an environment where the movement of the free electrons 32 is inhibited by the potential difference, the movement of the free electrons 32 around the metal molecules 31 constituting the metal film piece 3 is not inhibited in the other areas where the metal film piece 3 is formed, and the antibacterial effect can be exhibited. Therefore, if the metal film piece 3 can be formed in a dispersed state in the cloth 2, excellent antibacterial properties can be obtained. An example of an environment where a part of the area of ​​the metal film piece-formed cloth 1 is subjected to a potential difference is when, for example, metal push pins or screws are provided on the wall surface on which the metal film piece-formed cloth 1 is attached as an interior material, and the potential of these push pins or screws is made of an electric conductor with a different potential from that of the metal film piece-formed cloth 1, and they come into contact with a part of the metal film piece-formed cloth 1.

[0045] The antibacterial effect is considered to be effective if it reduces the number of viable bacteria rather than increasing them, since it decreases over time even if it does not have an immediate effect. In the present invention, the antibacterial activity value after 48 hours is set to 2.0 or more.

[0046] The metal film piece-forming fabric of the present invention thus constructed has an average color difference of 1.3 to 6.5, preferably 1.3 to 3.0, more preferably 1.3 to 1.5, measured at 9 equally spaced points in 3 vertical and 3 horizontal rows within a 25 mm square area, and the metal film pieces are formed so that the electrical resistance between two points on a plane is 100 MΩ or more. Therefore, the fabric can be produced by a simple method, for example, by immersing the fabric once in a composition for forming metal film pieces and drying it. Moreover, since only a single immersion and drying is required and the amount of metal used to form the metal film pieces is small, the fabric can be produced inexpensively.

[0047] Furthermore, by making the color difference of the metal film piece-forming fabric within a specified range, the design is not compromised, and by forming the metal film pieces in a dispersed state at least on the surface of each filament that makes up the fabric, the movement of free electrons in the metal molecules is ensured in the formation area of ​​each metal film piece, resulting in excellent antibacterial properties.

[0048] Furthermore, by setting the color difference of the metal film piece-forming fabric within a predetermined range, metal film pieces are formed in a dispersed state at least on the surface of each filament that constitutes the fabric, so that the fabric can be used without impairing the texture, such as the flexibility and flexibility, that are inherent to the material of the fabric.

[0049] In the above description, the fabric is immersed in the composition for forming metal film pieces, but the method of attaching the composition for forming metal film pieces to the fabric is not limited to the immersion method, and the composition may be applied by roll coating, flow coating, spray coating, etc. However, in the case of these application methods, the composition is easily applied to the surface of the fabric, but is difficult to apply to the inside, so there is a concern that it may be difficult to form metal film pieces in a dispersed state on the surface of each filament constituting the fabric on both the surface and the inside of the fabric. However, even if this happens, if it is confirmed that a metal film piece-formed nonwoven fabric is obtained in which the electrical resistance between two points on the plane of the metal film piece-formed fabric is 100 MΩ or more and the antibacterial activity value is 2.0 or more in a predetermined antibacterial activity test, it can be determined that the metal film pieces are formed in a required dispersed state. Effect of the Invention

[0050] As described above, according to the present invention, a fabric is immersed in a composition for forming metal film pieces, which contains a metal precursor liquid having a reaction product of at least one selected from the group consisting of metal complexes and metal salts with at least one selected from ammonia and amines, and an organic reducing agent, and then dried. The average color difference measured at nine equally spaced points in three vertical and three horizontal rows in a 25 mm square range is 1.3 to 6.5, so that the antibacterial effect can be exerted without impairing the design and texture of the fabric. Furthermore, by making the average color difference 3.0 or less, even a fabric with a more rigorous color evaluation can exhibit an antibacterial effect without impairing the design of the fabric. Furthermore, by making the electrical resistance between two points on a plane 100 MΩ or more, each metal molecule attached to each filament constituting the fabric can exchange electrons individually in units of metal film pieces, so that the entire fabric formed with these metal film pieces can exhibit an excellent antibacterial effect evenly in any part of the fabric. Moreover, the metal film pieces formed on the metal film piece-forming cloth are not dense metal films that ensure electrical conductivity, so they can be produced easily and at low cost. [Brief description of the drawings]

[0051] [Figure 1] FIG. 2(a) is a partial cross-sectional view showing an outline of the overall configuration of a metal film piece-formed fabric, and FIG. 2(b) is a partially enlarged view explaining the movement of electrons in the metal film piece-formed fabric. [Diagram 2] FIG. 1A is a partial cross-sectional view showing an outline of the overall configuration of a conventional metal film-formed fabric, and FIG. 1B is a partially enlarged view explaining the movement of electrons in the metal film-formed fabric. [Diagram 3] 1 is a graph showing the relationship between the absorption coefficient measured by a photoelectric colorimeter and the bacterial concentration of NBRC3972 (Escherchia coli). [Figure 4] FIG. 4 is a schematic diagram illustrating measurement sites for color difference in a metal film piece-formed fabric. [Diagram 5]1 is a graph showing the relationship between the immersion time of the metal film piece-forming composition in the metal film piece-forming nonwoven fabrics of the Examples and Comparative Examples and the color difference of the obtained metal film piece-forming nonwoven fabrics. [Figure 6] 1 is a graph showing the relationship between the color difference and the antibacterial activity value of metal film piece-formed nonwoven fabrics according to Examples and Comparative Examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] [Examples 1 to 13, Comparative Examples 1 to 4] (1. Preparation of copper complex aqueous solution) 13.38 g of copper formate tetrahydrate was added to 160 g of water and 24.47 g of 25% aqueous ammonia, and the mixture was stirred at room temperature (24.0°C) for 1 hour to obtain Cu. 2+ 198 g of an aqueous solution of copper complex with a concentration of 0.30 mmol / g was prepared. The resulting solution of metal precursor was deep blue when observed with the naked eye.

[0053] (2. Preparation of Aqueous Ascorbic Acid Solution) 124 g of water was added to 31 g of ascorbic acid, and the mixture was stirred at room temperature (24.0° C.) for 30 minutes to prepare 155 g of an aqueous ascorbic acid solution having an ascorbic acid concentration of 1.14 mmol / g. A colorless and transparent aqueous ascorbic acid solution was obtained.

[0054] (3. Preparation of composition for forming metal film pieces) The metal precursor liquid obtained in (1.) and the ascorbic acid aqueous solution obtained in (2.) were each cooled to 2°C, mixed in a ratio of 127.74 parts by mass of the metal precursor liquid to 100 parts by mass of the ascorbic acid aqueous solution, and stirred and mixed at room temperature for 20 minutes to obtain a composition for forming metal film pieces. Immediately after mixing, the mixture was dark green, but when mixing was continued, the obtained metal forming composition changed to yellow after 20 minutes.

[0055] (4. Application of the composition for forming metal film pieces to a substrate) A nonwoven fabric (Maeda Kosen Co., Ltd., trade name Splitop SP-1200E) was cut to a size of 25 mm x 25 mm and placed inside a glass screw tube bottle (13.5 ml, Φ14.5 mm x Φ24 mm x 50 mm) to prepare multiple tubes. Into these bottles, 13.5 ml of the composition for forming metal film pieces obtained above was poured and the nonwoven fabric was left in a state of being immersed, after which the bottles were covered and sealed with parafilm, and left to stand at 23.0° C. After being left to stand for different periods of time ranging from 10 minutes to 180 minutes, each nonwoven fabric was taken out of the bottle, washed with pure water, and then the moisture was blown off with a blower, followed by drying at 70° C. for 24 hours, to obtain a metal film piece-formed nonwoven fabric having copper attached to the surface.

[0056] [Copper evaluation] (1. Regarding adhesion status) Using a color difference meter (Konica Minolta CM-5), the L of each metal film-formed nonwoven fabric was measured. * a * b * The color space values ​​were measured. The measurement diameter of the color difference meter was φ8 mm, and the measurement points were 9 points equally spaced in 3 rows and 3 columns within a 25 mm square area, as shown in Figure 4. Color difference ΔE * If the value of the reference space is (L1, a1, b1) and the color space of each measured test piece is (L2, a2, b2), ab is calculated by the following formula (1).

[0057]

number

[0058] [Table 1]

[0059] (2. Conductivity Evaluation) The resistance between two points on the surface of each metal film-formed nonwoven fabric was measured using a digital multimeter (Keysight Technologies, 34401A). As a result, it was confirmed that the resistance exceeded the measurement limit of 100 MΩ, indicating that no conductivity was obtained.

[0060] (3. Antibacterial Evaluation) The metal film piece-formed nonwoven fabric obtained in Example 1 above was subjected to the following antibacterial activity test. As a control, the same antibacterial activity test was carried out using the nonwoven fabric before copper was attached (Comparative Example 1). The test bacteria used in the antibacterial test were NBRC3972 (Escherchia coli) obtained from the National Institute of Technology and Evaluation. The concentration of the bacteria in the solution was 9 x 10 5 ~3×10 6 The concentration of bacteria was adjusted to 0.065 and 0.170 (9×10 7 ~3×10 8 cfu / ml), which is reduced to 1 / 100, resulting in 9 x 10 5 ~3×10 6 A bacterial solution containing cfu / ml was prepared. The nonwoven fabric with the metal film piece was sterilized on both sides by ultraviolet irradiation. The sterilized test piece was placed in a sterilized petri dish, and the above 9 × 10 5 ~3×10 6 A test bacterial solution adjusted to a concentration of cfu / ml was dropped in 0.05 ml portions twice, a total of 0.1 ml. After culturing at 35±1° C. for 48 hours, the test specimen was placed in a sterilized stomacher bag and thoroughly washed out with 9.9 ml of SCDLP medium (manufactured by Nippon Pharmaceutical Co., Ltd.). The viable cell count was confirmed by agar plate culture method, and serial dilution was performed up to 1:10000 diluted water. 1 ml of each diluted cell solution was taken onto Petrifilm (Kikkoman Biochemifa EasyPlate for Escherichia coli and coliform bacteria count EC 61975) and cultured in an incubator at 35°C ± 1°C for 24 hours. From each dilution ratio, a film suitable for measurement (with grown colony counts of approximately 30 to 300 cfu) was selected, the colony count was carried out, and the antibacterial activity value was calculated. The results are shown in Table 2 and FIG.

[0061] [Table 2]

[0062] In Table 1, the viable cell count and antibacterial activity value were calculated according to the following formula. [Viable bacteria count] N=C×D×V N: number of live bacteria, C: number of colonies in the petri dish, D: dilution ratio, V: volume of SCDLP medium [Antibacterial activity value] Antibacterial activity value R = (U t -U0) - (A t -U0) U0: The average logarithm of the viable cell count immediately after inoculation of the untreated test specimen U t : Average logarithm of viable bacteria count on untreated test pieces after 48 hours A t : Average logarithm of viable bacteria count on antibacterial treated test pieces after 48 hours

[0063] From the above results, the nonwoven fabric having copper attached thereto according to the embodiment was able to obtain an excellent antibacterial activity with an antibacterial activity value of 2.0 or more.

[0064] The present invention can be embodied in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely illustrative in all respects and should not be interpreted as being limiting. The scope of the present invention is defined by the claims and is not limited to the text of the specification. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0065] 1 Metal film piece forming cloth 2 cloth 3 Metal film piece 31 Metal molecules 32 free electron

Claims

1. A fabric is immersed in a composition for forming a metal film comprising a metal precursor liquid having a reaction product of at least one selected from the group consisting of a metal complex and a metal salt with at least one selected from ammonia and an amine, and an organic reducing agent, and then dried, thereby forming metal film pieces in a dispersed state on the surface of each filament constituting the fabric, A metal film piece-formed fabric, characterized in that the average color difference measured at nine equally spaced points in three vertical and three horizontal rows within an area of ​​25 mm square is 1.3 to 6.

5.

2. 2. The metal film piece-formed fabric according to claim 1, wherein the average color difference measured at nine equally spaced points in three vertical and three horizontal rows within an area of ​​25 mm square is 1.3 to 3.

0.

3. 2. The metal film piece-forming fabric according to claim 1, wherein the electrical resistance between two points on the plane is 100 MΩ or more.

4. The plate was cut into pieces of 30 mm × 30 mm in size, sterilized, and then placed in a sterilized petri dish. NBRC3972 E. coli was added to the plate at 9 × 10 ５ ~3×10 ６ 2. The metal film piece-formed fabric according to claim 1, wherein 0.1 ml of a test bacterial solution adjusted to a concentration of cfu / ml is dropped onto the fabric, and the fabric is cultured at 35±1°C for 48 hours. The fabric is then thoroughly washed out using 9.9 ml of SCDLP medium, and the resulting solution is serially diluted to 1:10,000 diluted water. Each diluted bacterial solution is cultured at 35±1°C for 24 hours using an agar plate culture method, resulting in an antibacterial activity value of 2.0 or more.

5. 5. The metal film piece-forming fabric according to claim 1, wherein the metal is Cu.

6. 2. The metal film strip forming fabric according to claim 1, wherein the fabric is made of natural or synthetic fibers.

7. A step of immersing a cloth in a composition for forming a metal film piece, the composition comprising a metal precursor liquid having a reaction product of at least one selected from the group consisting of a metal complex and a metal salt with at least one selected from ammonia and an amine, and an organic reducing agent; drying the soaked fabric; A method for manufacturing a metal film-formed fabric, in which metal film pieces are formed in a dispersed state on at least the surface of each filament constituting the fabric, comprising: A method for producing a metal film piece-formed fabric, characterized in that the average color difference measured at nine equally spaced points in three vertical and three horizontal rows within a 25 mm square area is 1.3 to 6.5 by adjusting the immersion time and immersion temperature.

8. The method for producing a metal film piece-formed cloth according to claim 7, wherein the immersion time and immersion temperature are adjusted to make the average color difference measured at nine equally spaced points in three vertical and three horizontal rows within a 25 mm square area 1.3 to 3.

0.

9. A method for manufacturing a metal film-formed fabric as described in claim 7, in which metal film pieces are formed in a dispersed state at least on the surface of each filament constituting the fabric so that the electrical resistance between two points on a plane is 100 MΩ or more by adjusting the immersion time and immersion temperature.

10. The plate was cut into pieces of 25 mm × 25 mm in size, sterilized, and then placed in a sterilized petri dish. NBRC3972 E. coli was added to the plate at 9 × 10 ５ ~3×10 ６ 8. A method for producing a metal film piece-formed fabric according to claim 7, wherein 0.1 ml of a test bacterial solution adjusted to a concentration of cfu / ml is dropped onto the fabric, the test bacterial solution is cultured at 35±1°C for 48 hours, and then thoroughly washed out using 9.9 ml of SCDLP medium. The test bacterial solution is then serially diluted to 1:10,000 diluted water, and each diluted bacterial solution is cultured at 35±1°C for 24 hours using an agar plate culture method. The immersion time and immersion temperature are adjusted so that the antibacterial activity value is 2.0 or more.

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