Antimicrobial resin articles, packaging materials, building materials, textile products, filters, methods for manufacturing antimicrobial resin articles, and methods for imparting antimicrobial activity.

Abstract

The objective is to provide antimicrobial resin articles with a simple structure that can be easily manufactured and have excellent antimicrobial activity such as antibacterial activity and antiviral activity, as well as packaging materials, building materials, textile products, filters, methods for manufacturing antimicrobial resin articles, and methods for imparting antimicrobial activity. [Solution] An antibacterial resin article comprising only a hydrophilic resin substrate containing an organic acid having 1 to 10 carbon atoms, wherein the content of the organic acid having 1 to 10 carbon atoms is 0.2 to 30 wt% of the total mass of the antibacterial resin article, and packaging materials, building materials, fabric products, and filters using the antibacterial resin article are provided. Furthermore, a method for producing an antibacterial resin article and a method for imparting antimicrobial activity are provided, characterized by immersing a hydrophilic resin substrate in a liquid containing an organic acid having 1 to 10 carbon atoms.

Description

[Technical Field]

[0001] The present invention relates to antimicrobial resin articles, packaging materials, building materials, textile products, filters, methods for manufacturing antimicrobial resin articles, and methods for imparting antimicrobial activity. [Background technology]

[0002] Antimicrobial resin articles, such as resin films, which possess antimicrobial activity including antibacterial and antiviral activity, are used, for example, in food packaging materials and building materials. For example, Patent Documents 1 and 2 disclose a laminated resin film in which an antibacterial layer is formed on one side of a substrate layer. In this resin film, the side with the antibacterial layer has antimicrobial activity. Such a resin film is usually obtained by applying a solution containing an antibacterial agent to one side of a substrate layer and drying it to form an antibacterial layer on one side of the substrate. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 2008-545761 [Patent Document 2] U.S. Patent Application Publication No. 2005 / 0129937 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Further technological improvements are desired for conventional antibacterial resin articles such as the resin films described in Patent Documents 1 and 2. The main objective of the present invention is to provide an antimicrobial resin article with a simple structure that can be easily manufactured and has excellent antimicrobial activity such as antibacterial activity and antiviral activity, as well as packaging materials, building materials, fabric products, filters, methods for manufacturing antimicrobial resin articles, and methods for imparting antimicrobial activity. [Means for solving the problem]

[0005] The present invention includes the following configuration. [1]: An antibacterial resin article consisting only of a hydrophilic resin substrate containing an organic acid having 1 to 10 carbon atoms, An antibacterial resin article wherein the content of the organic acid having 1 to 10 carbon atoms is 0.2 to 30 wt% relative to the total mass of the antibacterial resin article. [2]: The antimicrobial resin article according to [1], wherein the hydrophilic resin substrate comprises at least one selected from the group consisting of polyamide, cellulose resin, and polyurethane. [3]: The antimicrobial resin article according to [1] or [2], wherein the hydrophilic resin substrate comprises a polyamide, and the polyamide comprises either or both nylon 6 and nylon 66. [4]: The antimicrobial resin article according to any one of [1] to [3], comprising at least one of citric acid and acetic acid as the organic acid having 1 to 10 carbon atoms. [5]: The antibacterial resin article according to any one of [1] to [4], wherein the hydrophilic resin substrate is a hydrophilic resin film. [6]: The antibacterial resin article according to any one of [1] to [5], wherein the hydrophilic resin substrate is a hydrophilic resin fiber substrate. [7]: Packaging materials containing antimicrobial resin articles as described in [5]. [8]:[5] Building materials containing antimicrobial resin articles. [9]:[6] Fabric products containing antimicrobial resin articles.

[10] : A filter containing the antimicrobial resin article described in [6].

[11] : A method for producing an antimicrobial resin article according to any one of [1] to [5], comprising immersing a hydrophilic resin substrate in a liquid containing an organic acid having 1 to 10 carbon atoms.

[12] A method for imparting antimicrobial activity to a hydrophilic resin substrate, comprising immersing the hydrophilic resin substrate in a liquid containing an organic acid having 1 to 10 carbon atoms. [Effects of the Invention]

[0006] According to the present invention, there is an antimicrobial resin article that has a simple structure, can be easily manufactured, and has excellent antimicrobial activity such as antibacterial activity and antiviral activity, as well as packaging materials, building materials, fabric products, filters using the same, a method for manufacturing the antimicrobial resin article, and a method for imparting antimicrobial activity. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows the number of viable bacteria (common logarithm) in each test specimen of the examples and comparative examples. [Figure 2] This figure shows the viral infectivity titer (common logarithm) in each test specimen of the examples and comparative examples. [Modes for carrying out the invention]

[0008] In the specification and claims, numerical ranges expressed using "~" include the numbers at both ends of the "~". For example, "A~B" means A or greater and B or less.

[0009] [Antibacterial resin articles] The antibacterial resin article according to the embodiment is an article consisting solely of a hydrophilic resin substrate containing an organic acid having 1 to 10 carbon atoms (hereinafter also simply referred to as "organic acid A"). The content of organic acid A in the antibacterial resin article according to the embodiment is 0.2 to 30 wt% of the total mass of the antibacterial resin article.

[0010] As a hydrophilic resin substrate, for example, a substrate composed of a resin that is both permeable to drugs and hydrophilic can be used. However, "drug penetration" refers to the property of organic acid A adhering to the surface of a hydrophilic resin substrate to penetrate into the interior of the hydrophilic resin substrate, and of organic acid A that has penetrated into the interior of the hydrophilic resin substrate to seep out onto the surface of the hydrophilic resin substrate. The hydrophilicity of the resin can be represented by, for example, the water absorption rate measured by the ASTM D570 method. In the present invention, the "hydrophilic resin" means a resin having a water absorption rate of 0.5 or more. Since the permeability of organic acid A and the adjustment of the concentration of organic acid A are facilitated, the water absorption rate of the resin is preferably 0.75 or more, and more preferably 1.0 or more.

[0011] The hydrophilic resin substrate contains organic acid A, and it is preferable that organic acid A has penetrated. It is more preferable that organic acid A has penetrated at least near the surface of the hydrophilic resin substrate, and it is not necessarily required to penetrate throughout the entire thickness direction of the hydrophilic resin substrate.

[0012] The hydrophilic resin constituting the hydrophilic resin substrate is not particularly limited, and examples thereof include polyamide, cellulose resin, and polyurethane. The hydrophilic resin preferably contains at least one selected from the group consisting of polyamide, cellulose resin, and polyurethane, and polyamide is particularly preferable in terms of particularly excellent permeability of organic acid A and concentration adjustment. As the hydrophilic resin constituting the hydrophilic resin substrate, one kind may be used alone, or two or more kinds may be used in combination.

[0013] Examples of polyamide include nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 6T, nylon 9T, nylon M5T, and nylon 612. In terms of excellent tensile strength and burst strength when formed into a film, the polyamide preferably contains either one or both of nylon 6 and nylon 66, and more preferably contains nylon 6. Examples of the cellulose resin include nitrocellulose and acetylcellulose. Examples of the polyurethane include polyester-based thermoplastic polyurethane, polyether-based thermoplastic polyurethane, and polycarbonate-based thermoplastic polyurethane.

[0014] The hydrophilic resin substrate may be a hydrophilic resin film or a hydrophilic resin fiber substrate. The hydrophilic resin film may be a single-layer film or a laminated film formed by laminating multiple single-layer films. When the hydrophilic resin film is a laminated film, the hydrophilic resins constituting each laminated single-layer film may be of the same type or different types, but it is preferable that at least one single-layer film contains polyamide.

[0015] The hydrophilic resin constituting the hydrophilic resin fiber base material is not particularly limited, and examples include polyamide, cellulose resin, and polyurethane. Preferably, the hydrophilic resin constituting the hydrophilic resin fiber base material contains at least one selected from the group consisting of polyamide, cellulose resin, and polyurethane, and polyamide is particularly preferred because it is particularly excellent in terms of permeability and concentration adjustment of organic acid A. The hydrophilic resin used to make up the hydrophilic resin substrate may be one type used alone, or two or more types may be used in combination.

[0016] The thickness of the hydrophilic resin substrate is preferably 0.1 micrometers or more, more preferably 1 micrometer or more, even more preferably 10 micrometers or more, and particularly preferably 100 micrometers or more. Furthermore, the thickness of the hydrophilic resin substrate is preferably 50,000 micrometers or less, more preferably 25,000 micrometers or less, even more preferably 10,000 micrometers or less, and particularly preferably 1,000 micrometers or less. If the thickness of the hydrophilic resin substrate is above the lower limit, damage to the hydrophilic resin substrate during use is prevented, and the sustained release period of organic acid A tends to be maintained. If the thickness of the hydrophilic resin substrate is below the upper limit, the flexibility of the hydrophilic resin substrate is more easily maintained, and antibacterial resin articles can be provided in various locations such as curved surfaces. The preferred lower and upper limits for the thickness of the hydrophilic resin substrate can be any combination, for example, 0.1 to 50,000 micrometers is preferred, 1 to 25,000 micrometers is more preferred, 10 to 10,000 micrometers is even more preferred, and 100 to 1,000 micrometers is particularly preferred.

[0017] Organic acid A is an organic acid having 1 to 10 carbon atoms. Specific examples of organic acid A include, for instance, oxalic acid, glycolic acid, lactic acid, tartaric acid, succinic acid, fumaric acid, malic acid, orotic acid, citric acid, gluconic acid, salicylic acid, quinic acid, coumaric acid, caffeic acid, ferulic acid, malonic acid, glitalic acid, isophthalic acid, suberic acid, adipic acid, and azelaic acid. As organic acid A, carboxylic acids having 1 to 10 carbon atoms can also be used. Examples of carboxylic acids having 1 to 10 carbon atoms include formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), isobutyric acid (C4H8O2), and valeric acid (C5H 10 O2), caproic acid (C6H 12 O2), enanthic acid (C7H 14 O2), caprylic acid (C8H 16Examples include fatty acids such as O2. As the carboxylic acid having 1 to 10 carbon atoms, at least one selected from the group consisting of these exemplified carboxylic acids having 1 to 10 carbon atoms is preferred, and at least one selected from the group consisting of carboxylic acids having 2 to 6 carbon atoms is more preferred. Organic acid A may be used alone or in combination of two or more types.

[0018] Citric acid and acetic acid are preferred as organic acid A because they are found in food and are extremely safe. In the antimicrobial resin article according to the embodiment, it is preferable that the hydrophilic resin constituting the hydrophilic resin substrate contains a polyamide, and that the organic acid A contains at least one of citric acid and acetic acid. When the hydrophilic resin and organic acid A are in combination with these, the organic acid A tends to be easily adsorbed onto the hydrophilic resin substrate, and the antimicrobial activity tends to be sustained.

[0019] The content of organic acid A in the antimicrobial resin article is preferably 0.2 wt% or more, more preferably 0.5 wt% or more, even more preferably 0.75 wt% or more, and particularly preferably 1.0 wt% or more, based on the total mass of the antimicrobial resin article. If the content of organic acid A is above the lower limit, sufficient antimicrobial activity will be exhibited. The content of organic acid A in the antimicrobial resin article is preferably 30 wt% or less, more preferably 20 wt% or less, and even more preferably 10 wt% or less, based on the total mass of the antimicrobial resin article. If the content of organic acid A is below the upper limit, organic acid A will not undergo phase separation, and the antimicrobial activity on the surface of the resin article will not become non-uniform. The lower and upper limits of the content of organic acid A may be arbitrarily combined, for example, 0.2 to 30 wt%, 0.5 to 20 wt%, 0.75 to 15 wt%, or 1.0 to 10 wt%.

[0020] The inclusion of organic acid A in the hydrophilic resin substrate gives the surface of the antimicrobial resin article antimicrobial activity. As for antimicrobial activity, at least one selected from the group consisting of antibacterial activity, antifungal activity, and antiviral activity is preferred. Antimicrobial activity is evaluated by methods such as those specified in JIS Z 2801:2012 (Antibacterial processed products - Antimicrobial test methods and antimicrobial effects). Antifungal activity is evaluated by methods such as those specified in JIS Z 2911:2018 (Test methods for mold resistance). Antiviral activity is evaluated using test methods such as those specified in ISO 21702:2019 (Measurement of antiviral activity of plastics and other non-porous surfaces).

[0021] The antibacterial activity of the surface of the antibacterial resin article is preferably antibacterial activity against at least one Gram-negative bacterium other than Escherichia coli, such as Salmonella, Enterobacter, Pseudomonas, Moraxella, Helicobacter, Bdellovibrio, Acetobacter, and Legionella. The surface of the antimicrobial resin article preferably has antimicrobial activity against at least one Gram-positive bacteria other than Staphylococcus aureus, such as Firmicutes species including Bacillus, Lactobacillus, Clostridium, Thermoanaerobacter, Haloanaerobium, Natraanaerobius, and Erysipelotrichus, and actinomycetes species such as Actinomyces, Streptomyces, and Bifidobacterium.

[0022] The antifungal activity of the surface of the antimicrobial resin article is preferably antifungal activity against at least one species selected from the group consisting of molds and yeasts other than Aspergillus and Cladosporium, such as Penicillium, Trichoderma, Fusarium, Neurospora, Aureobasidium, Saccharomyces, Candida, Cryptococcus, and Schizosaccharomyces.

[0023] The antiviral activity of the surface of the antibacterial resin article is preferably antiviral activity against at least one virus selected from the group consisting of enveloped viruses, such as varicella-zoster virus, smallpox virus, hepatitis B virus, hepatitis C virus, Japanese encephalitis virus, Zika virus, rubella virus, SARS coronavirus, MERS coronavirus, COVID-19 virus, hepatitis D virus, measles virus, human respiratory syncytial virus, rabies virus, Crimean-Congo hemorrhagic fever virus, Ebola virus, Marburg virus, human immunodeficiency virus, influenza A virus (H1N1, H3N2, etc.), and adult T-cell leukemia virus. The surface of the antimicrobial resin article preferably has antiviral activity against at least one virus selected from the group consisting of non-enveloped viruses, such as feline calicivirus, adenovirus, human papillomavirus, poliovirus, hepatitis A virus, norovirus, enterovirus, and rotavirus. The surface of the antibacterial resin article preferably has antiviral activity against the novel coronavirus.

[0024] <Manufacturing method> The antimicrobial resin article according to this embodiment is obtained by immersing a hydrophilic resin substrate in a liquid containing organic acid A (hereinafter also referred to as "liquid B"), for example, to impart antimicrobial activity to the surface of the hydrophilic resin substrate. With the hydrophilic substrate immersed in liquid B, stirring may be performed as needed, or if using a container with a lid, the container may be shaken. After immersion, for example, the hydrophilic substrate is removed from liquid B, washed with water, and air-dried to obtain an antibacterial resin article.

[0025] The concentration of organic acid A in liquid B is preferably 0.5 wt% or more, more preferably 1.0 wt% or more, even more preferably 2.0 wt% or more, and particularly preferably 3.0 wt% or more. If the concentration of organic acid A is above the lower limit, there is a tendency to obtain an antimicrobial resin article with sufficient antimicrobial activity. The concentration of organic acid A is preferably 100 wt% or less, more preferably 70 wt% or less, even more preferably 55 wt% or less, and particularly preferably 50 wt% or less. If the concentration of organic acid A is below the upper limit, the viscosity of liquid B is not high, and the burden on the manufacturing process is not large. The lower and upper limits of the concentration of organic acid A may be arbitrarily combined, for example, 0.5 to 100 wt%, 1.0 to 70 wt%, 2.0 to 55 wt%, or 3.0 to 50 wt%.

[0026] Liquid B may contain a component that generates organic acid A in the liquid, instead of organic acid A itself. A component that generates organic acid A is a component that produces organic acid A through decomposition or other means.

[0027] The solvent used to dissolve organic acid A is preferably water, but is not limited to it. For example, organic solvents such as methanol, ethanol, isopropyl alcohol, hexane, heptane, toluene, and xylene may be used. The solvent may be used individually or in combination of two or more.

[0028] When immersing the hydrophilic resin substrate in liquid B, the immersion time is preferably 0.1 hours or more, more preferably 0.2 hours or more, even more preferably 0.5 hours or more, and particularly preferably 1 hour or more. If the contact time is above the lower limit, sufficient antimicrobial activity tends to be easily obtained. The immersion time is preferably 120 hours or less, more preferably 72 hours or less, even more preferably 48 hours or less, and particularly preferably 24 hours or less. If the contact time is below the upper limit, the influence of changes in the concentration of liquid B due to solvent evaporation is sufficiently small. The lower and upper limits of the immersion time may be arbitrarily combined, for example, 0.1 to 120 hours, 0.2 to 72 hours, 0.5 to 48 hours, or 1 to 24 hours.

[0029] The temperature of liquid B when immersing the hydrophilic resin substrate is preferably 0 to 50°C, and more preferably 5 to 35°C.

[0030] When drying the hydrophilic resin substrate after immersion in liquid B, it is preferable to air dry it at, for example, 0 to 50°C, and more preferably at 5 to 35°C.

[0031] The hydrophilic resin substrate may be surface-treated before immersion in liquid B. Examples of surface treatments include surface oxidation treatments such as corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment, or sandblasting. Of these, surface oxidation treatment is preferred, and corona treatment is particularly preferred, from the viewpoint of surface treatment effectiveness, productivity, and manufacturing cost.

[0032] <Application> The antibacterial resin article according to the embodiment can be widely used in places where it is desired to reduce the activity of microorganisms. When using a hydrophilic resin film as the hydrophilic resin base material, it can be used in places where it is desired to reduce the activity of microorganisms, for example, on the surface of a desk, building wall materials, wallpapers, ceiling materials, floor materials, doorknobs, doors, straps, handrails, etc. for building materials applications, interior materials of moving objects such as automobiles, trains, ships, airplanes, etc., building materials and equipment in medical facilities, and packaging materials for medical instruments. Also, when using a hydrophilic resin fiber base material as the hydrophilic resin base material, it can be used, for example, in filters provided at ventilation openings, cloth products such as curtains, etc.

[0033] The antibacterial resin article using a hydrophilic resin film as the hydrophilic resin base material is useful for building and building materials applications. When used for building materials applications, it preferably has a property of being easy to bend, and a bending strength is required such that cracks or breakage do not occur even when bent. As an index, the bending strength measured by the ASTM D790 method is used, and preferably 300 kg / cm 2 or more, more preferably 400 kg / cm 2 or more, even more preferably 500 kg / cm 2 or more. Also, preferably 20,000 kg / cm 2 or less, more preferably 15,000 kg / cm 2 or less, even more preferably 10,000 kg / cm 2 or less. Also, it preferably has a strength that can withstand scratching from the outside. As an index, the Rockwell hardness measured by the ASTM D785 method is used, and preferably R50 or more, preferably R75 or more, and even more preferably R100 or more. Also, preferably R200 or less, preferably R150 or less, and even more preferably R125 or less.

[0034] [[ID=le4]]<Function and effect> The antimicrobial resin article according to this embodiment contains organic acid A, and exhibits antimicrobial activity because organic acid A is present on its surface. Furthermore, even if the organic acid A present on the surface is consumed and decreases, at least a portion of the organic acid A present in the hydrophilic resin substrate gradually seeps out to the surface of the hydrophilic resin substrate, thus maintaining a certain degree of antimicrobial activity. In addition, the antimicrobial resin article according to this embodiment has a simple structure and is easy to manufacture. Furthermore, by using a hydrophilic resin as the material for the hydrophilic resin substrate, and combining it with at least one of citric acid and acetic acid as organic acid A, the adsorption capacity of the hydrophilic resin substrate to organic acid A increases, thereby enhancing the sustained antimicrobial activity.

[0035] [Method for imparting antimicrobial activity] The method for imparting antimicrobial activity according to the embodiment involves immersing a hydrophilic resin substrate in a liquid B containing organic acid A, thereby imparting antimicrobial activity to the hydrophilic resin substrate. With the hydrophilic substrate immersed in liquid B, stirring may be performed as needed, or if using a container with a lid, the container may be shaken. After immersion, for example, the hydrophilic substrate is removed from liquid B, washed with water, and air-dried to obtain an antibacterial resin article.

[0036] As the hydrophilic resin substrate, the hydrophilic resin substrates exemplified in the description of the antibacterial resin article described above can be used, and the preferred embodiment is the same. As organic acid A and liquid B, the organic acid A and liquid B exemplified in the above-described description of the antibacterial resin article can be used, and the preferred embodiments are the same.

[0037] When immersing the hydrophilic resin substrate in liquid B, the immersion time is preferably 0.1 hours or more, more preferably 0.2 hours or more, even more preferably 0.5 hours or more, and particularly preferably 1 hour or more. If the contact time is above the lower limit, sufficient antimicrobial activity tends to be easily obtained. The immersion time is preferably 120 hours or less, more preferably 72 hours or less, even more preferably 48 hours or less, and particularly preferably 24 hours or less. If the contact time is below the upper limit, the influence of changes in the concentration of liquid B due to water evaporation is sufficiently small. The lower and upper limits of the immersion time may be arbitrarily combined, for example, 0.1 to 120 hours, 0.2 to 72 hours, 0.5 to 48 hours, or 1 to 24 hours.

[0038] The temperature of liquid B when immersing the hydrophilic resin substrate is preferably 0 to 50°C, and more preferably 5 to 35°C.

[0039] When drying the hydrophilic resin substrate after immersion in liquid B, it is preferable to air dry it at, for example, 0 to 50°C, and more preferably at 5 to 35°C.

[0040] The hydrophilic resin substrate may be surface-treated before immersion in liquid B. Examples of surface treatments include surface oxidation treatments such as corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment, or sandblasting. Of these, surface oxidation treatment is preferred, and corona treatment is particularly preferred, from the viewpoint of surface treatment effectiveness, productivity, and manufacturing cost. [Examples]

[0041] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0042] [Example 1] Four 5cm square nylon 6 films with a thickness of 300μm were prepared, and the weight of each was measured. The average weight of the nylon 6 films was 862.8mg. At room temperature (25℃), 50g of citric acid (manufactured by Ken-ei Pharmaceutical Co., Ltd.) and 50g of tap water were placed in a 300mL glass container with a lid, and the mixture was shaken with the lid closed. After intermittent shaking for 30 minutes, the mixture was allowed to stand for 2 hours to obtain a 50wt% citric acid aqueous solution. The lid of the glass container was removed, and the nylon 6 films were slowly placed in one by one and immersed in the citric acid aqueous solution. The container was then stored for 12 hours, with intermittent shaking. After storage, each nylon 6 film was removed from the citric acid aqueous solution, washed with tap water for about 5 seconds, roughly wiped dry with a tissue, and then air-dried on a metal mesh. After 98 hours, the weight of the nylon 6 films was measured, and the average weight was 868.3mg. The weight increase due to citric acid was 5.5 mg, representing 0.63 wt% of the total. This was designated as test specimen 1.

[0043] [Example 2] Test specimen 2 was prepared in the same manner as in Example 1, except that the concentration of the citric acid aqueous solution was 2.7 wt%. The weight increase due to citric acid in the nylon 6 film after air drying was 0.42 wt% of the total, and this was designated as test specimen 2.

[0044] [Example 3] Four 5cm square nylon 6 films with a thickness of 300μm were prepared, and the weight of each was measured. The average weight of the nylon 6 films was 837.5mg. At room temperature (25℃), 5.11g of glacial acetic acid (manufactured by Matsuba Pharmaceutical Co., Ltd.) and 145g of tap water were placed in a 300mL glass container with a lid, and the container was shaken to mix, obtaining an acetic acid aqueous solution with a glacial acetic acid concentration of 3.4wt%. The lid of the glass container was removed, and the nylon 6 films were slowly added one by one and immersed in the acetic acid aqueous solution. The density of the aqueous solution was not high, and some nylon 6 films settled while others remained in the liquid, but the container was shaken well to ensure good contact with the aqueous solution. The container was then stored for 12 hours, with intermittent shaking. After storage, each nylon 6 film was removed from the acetic acid aqueous solution, washed with tap water for about 5 seconds, the moisture was roughly wiped off with a tissue, and then it was left to air dry on a metal mesh. After 98 hours, the weight of the nylon 6 film was measured, and the average weight was 839.8 mg. The weight increase due to acetic acid was 2.3 mg, or 0.27 wt% of the total. This was designated as test specimen 3.

[0045] [Example 4] Test specimen 4 was prepared in the same manner as in Example 3, except that the concentration of the acetic acid aqueous solution was set to 0.33 wt%. The weight increase due to acetic acid in the nylon 6 film after air drying was 0.20 wt% of the total, and this was designated as test specimen 4.

[0046] [Comparative Example 1] Four 5cm square nylon 6 films with a thickness of 300μm were prepared, and the weight of each was measured. The average weight of the nylon 6 films was 877.8mg. 150g of tap water was placed in a 300mL glass container with a lid at room temperature (25℃), and the lid was closed. The lid of the glass container was removed, and the nylon 6 films were slowly placed in one by one and immersed in the water. The density of water and nylon 6 are similar, and some nylon films settled while others remained submerged in the liquid, but the container was shaken well to ensure good contact with the water. The container was then stored for 12 hours, with intermittent shaking. After storage, each nylon 6 film was removed from the water, washed with tap water for about 5 seconds, roughly wiped dry with a tissue, and then air-dried on a metal mesh. After 98 hours, the weight of the nylon 6 films was measured, and the average weight was 875.8mg. The weight change was -2mg, but this was due to humidity and was below the detection limit. Therefore, the weight increase was considered to be 0 mg, and this was designated as test piece 5.

[0047] [Comparative Example 2] Test specimen 6 was prepared in the same manner as in Example 3, except that the concentration of the acetic acid aqueous solution was set to 0.033 wt%. The weight increase due to acetic acid in the nylon 6 film after air drying was below the detection limit, and this was designated as test specimen 6.

[0048] [Antibacterial testing] Antimicrobial testing was performed on test specimens 1-6 using a method based on JIS Z 2801:2012. Untreated film (KISTEC) was used as the untreated sample. Escherichia coli (NBRC3972) was used as the test bacterium. The test conditions were as follows. <Test Conditions> • Dilution of test bacteria: 1 / 500NB • Inoculation amount of test bacteria: 0.4 mL / sample • Sterilization of test specimens: Wiping with anhydrous ethanol • Operating conditions: Dark, 35°C, relative humidity 90% or higher • Duration of action: 24 hours • Adhesive film: Reinforced polyethylene (Stomacher 80 type, ORGANO), 40mm x 40mm x 0.09mm thick

[0049] 0.4 mL of the test bacterial suspension was dropped onto the surface of each of the test specimens 1-6, and an adhesive film was placed over them, pressing down to ensure the test bacterial suspension was evenly distributed. 24 hours after the start of the antibacterial test, each of the test specimens 1-6 was placed in a sterile stomacher bag, 10 mL of SCDLP broth medium was added, and the bacterial suspension was thoroughly washed out to obtain the sample. 1 mL of the sample was cultured on standard agar medium at 35°C for 48 hours, and the number of viable cells was measured. The antibacterial activity was evaluated based on the number of viable cells in the washings. Separately, 0.4 mL of the test bacterial solution was dropped onto the surface of two unprocessed films as comparative test specimens. A contact film was then placed over each specimen and pressed down to ensure the test bacterial solution was evenly distributed. The number of viable bacteria (initial value) was measured immediately after the start of the test on one of the two comparative test specimens, and the number of viable bacteria (unprocessed) was measured 24 hours after the start of the antibacterial test on the other specimen. The number of viable bacteria (initial value) on the comparative test specimen immediately after the start of the test was 4.2 on a common logarithm, and the number of viable bacteria on the comparative test specimen 24 hours later was 6.0 on a common logarithm. When the number of viable bacteria (common logarithm) in the comparative test piece 24 hours after the start of the test is A, and the number of viable bacteria (common logarithm) in each test piece 24 hours after the start of the test is B, the antibacterial activity value was calculated using the following formula. A higher antibacterial activity value indicates higher antibacterial activity. Antibacterial activity value = AB Figure 1 shows the number of viable cells (common logarithmic scale) in each test specimen. Table 1 shows the conditions for each example, the number of viable cells (common logarithmic scale) in each test specimen, and the results of the antibacterial activity values.

[0050] [Table 1]

[0051] As shown in Figure 1 and Table 1, Examples 1 to 4, in which the organic acid content in the test specimens was within a specific range, showed higher antibacterial activity values ​​and superior antibacterial properties compared to Comparative Examples 1 and 2, in which the organic acid content in the test specimens was lower. Furthermore, Example 1, which had a higher citric acid content in the test specimens, showed even higher antibacterial activity values ​​and particularly superior antibacterial properties compared to Example 2. Example 3, which had a higher acetic acid content in the test specimens, showed even higher antibacterial activity values ​​and particularly superior antibacterial properties compared to Example 4.

[0052] [Antiviral performance evaluation test] Antiviral performance evaluation tests were conducted on test specimens 1, 4, and 6 using a method based on ISO 21702. Unprocessed film (KISTEC) was used as the unprocessed sample. The viruses used as test viruses are listed below. The test conditions were as follows. <Test virus> Influenza A virus (ATCC VR-1679) Host cell: MDCK cell (ATCC CCL-34) <Test Conditions> • Sterilization of test samples: None ·Working temperature: 25℃ • Duration of action: 24 hours • Adhesive film: Polypropylene film (VF-10, KOKUYO), 40mm x 40mm

[0053] The viral infectivity titer (common logarithm) was measured using the plaque assay method for the unprocessed samples after testing, as well as for test pieces 1, 4, and 6. When the viral infectivity titer (common logarithm) of the unprocessed sample is denoted as C, and the viral infectivity titer (common logarithm) of each test specimen is denoted as D, the antiviral activity value was calculated using the following formula. A higher antiviral activity value indicates higher antiviral activity. Antiviral activity value = CD Figure 2 shows the results of measuring the viral infectivity titer (common logarithm) using the plaque assay method. Table 2 shows the conditions for each example, the viral infectivity titer (common logarithm) for each test piece, and the antiviral activity values.

[0054] [Table 2]

[0055] As shown in Figure 2 and Table 2, in Examples 1 and 4, where the organic acid content in the test specimens was within a specific range, the antiviral activity values ​​were higher and superior antiviral properties were exhibited compared to Comparative Example 2, which had a low organic acid content in the test specimens.

Claims

1. An antibacterial resin article consisting solely of a hydrophilic resin substrate containing an organic acid having 1 to 10 carbon atoms, wherein the hydrophilic resin substrate is permeable to drugs, and the organic acid is impregnated into the hydrophilic resin substrate, The content of the C1-C10 organic acid is 0.2-30 wt% relative to the total mass of the antibacterial resin article. The hydrophilic resin substrate comprises a polyamide, and the polyamide comprises either or both of nylon 6 and nylon 66. An antibacterial resin article comprising citric acid as the aforementioned organic acid having 1 to 10 carbon atoms.

2. The antibacterial resin article according to claim 1, wherein the hydrophilic resin substrate is a hydrophilic resin film.

3. The antibacterial resin article according to claim 1, wherein the hydrophilic resin substrate is a hydrophilic resin fiber substrate.

4. A packaging material comprising the antibacterial resin article described in claim 2.

5. A building material comprising the antibacterial resin article described in claim 2.

6. A fabric product comprising the antibacterial resin article described in claim 3.

7. A filter comprising the antibacterial resin article described in claim 3.

8. A method for producing an antibacterial resin article according to claim 1, comprising immersing a hydrophilic resin substrate in a liquid containing an organic acid having 1 to 10 carbon atoms.

9. A method for imparting antimicrobial activity to a hydrophilic resin substrate, comprising immersing a hydrophilic resin substrate containing either or both nylon 6 and nylon 66 in a solution containing citric acid, thereby imparting antimicrobial activity to the hydrophilic resin substrate.

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