Antimicrobial composition

Abstract

To provide an antimicrobial composition that exhibits superior antimicrobial effect on water-exposed environments and high-frequency contact surfaces.SOLUTION: An antimicrobial agent composition comprising the following components (A), (B), and (C): (A) a water-dispersible polyurethane; (B) a water-based dispersant; and (C) a silver-based antimicrobial agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an antibacterial composition and an antibacterial method. [Background technology]

[0002] The administration of antibiotics contributes significantly to the cure of microbial infections and the improvement of patient prognosis. However, in recent years, various drug-resistant bacteria that are resistant to antibiotics have been identified, making treatment of infectious diseases increasingly difficult. It is estimated that if countermeasures are not taken, the number of deaths from drug-resistant bacteria will reach 10 million per year by 2050 (Non-Patent Document 1). To prevent infection by drug-resistant bacteria, especially in hospitals, it is necessary to remove drug-resistant bacteria from target surfaces by regularly cleaning water-related areas (Non-Patent Document 2), which are considered reservoirs of drug-resistant bacteria, and surfaces that are frequently touched by various people, including patients and medical professionals. However, issues remain, such as the complexity of this process and the tendency for the bacteria to regrow on target surfaces after cleaning. The target water-related areas in hospitals are typically cleaned once a day, which is insufficient to maintain low bacterial counts in areas where drug-resistant bacteria frequently adhere. Therefore, antibacterial technology is needed to suppress bacterial growth on the target surfaces between cleanings. Water resistance is also required to suppress bacterial growth in water-related environments.

[0003] It has long been known that metal ions such as silver ions and copper ions, as well as quaternary ammonium salts, have antibacterial properties. However, these antibacterial agents are easily washed away when sprayed onto surfaces that come into contact with water, making them ineffective as a means of maintaining the antibacterial properties of target surfaces. Meanwhile, in recent years, from the perspective of protecting the global environment, coating agent manufacturers and others have been actively switching to environmentally friendly products, and demand for water-based resins is expanding in place of solvent-based resins that use organic solvents. For example, research into water-based acrylic resins, urethane resins, epoxy resins, etc. has progressed, and these resins are being used in applications such as paints for automobiles and building materials, coating agents for films and metals, and adhesives. As an example of the use of aqueous resins in antibacterial coatings, for example, a coating composition has been proposed in which an antibacterial agent such as a quaternary ammonium salt is mixed with an aqueous resin as an antibacterial coating composition having durability and antibacterial efficacy (Patent Document 1). However, there have been no reports to date on the antibacterial effect of a composition containing a water-based urethane resin and a silver-based antibacterial agent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-167011 [Non-patent literature]

[0005] [Non-Patent Document 1] Tackling a crisis for the health and wealth of nations: The review on antimicrobial resistance (2016) [Non-patent document 2] Nature medicine (2020) 941-951 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention relates to providing an antibacterial composition that exhibits excellent antibacterial effects, particularly in water-related environments and on surfaces that are frequently touched. [Means for solving the problem]

[0007] The present inventors have discovered that when a water-dispersible polyurethane is mixed with an aqueous dispersant and a silver-based antibacterial agent and then surface-treated, a treated film with high water resistance and abrasion resistance is formed, and an excellent antibacterial effect is also exhibited.

[0008] That is, the present invention relates to the following 1) to 4). 1) The following components (A), (B), and (C); (A) Water-dispersible polyurethane (B) Water-based dispersant (C) Silver-based antibacterial agent An antibacterial composition comprising: 2) A treated film formed on a target surface using the antibacterial composition. 3) An antibacterial sheet impregnated with the above antibacterial composition. 4) An antibacterial method, which comprises applying the antibacterial composition to a target surface. [Effects of the Invention]

[0009] According to the present invention, it is possible to impart high water resistance, abrasion resistance and antibacterial properties to a target surface, and to suppress infection by drug-resistant bacteria and the like via the target surface. [Brief explanation of the drawings]

[0010] [Figure 1] 4 shows the particle size measurement results of silver oxide. DETAILED DESCRIPTION OF THE INVENTION

[0011] The antibacterial composition of the present invention contains a water-dispersible polyurethane as component (A). Water-dispersible polyurethanes are prepared by dispersing a urethane resin in water. Water-dispersible polyurethanes are generally broadly classified into forced emulsification types and self-emulsification types depending on their production method, and the self-emulsification types are further classified into anionic, cationic, and nonionic types. In the present invention, any type can be used without particular limitation, but it is preferable to use a self-emulsification type water-dispersible polyurethane from the viewpoints of storage stability of the dispersion and water resistance of the surface of the formed film. One or more types of water-dispersible polyurethanes can be used.

[0012] Urethane resin is a general term for polymeric compounds having urethane bonds, and is industrially obtained by the polyaddition reaction of polyol and polyisocyanate. The polyol is a compound having two or more hydroxy groups in one molecule, and examples thereof include polyether polyol, polycarbonate polyol, and polyester polyol. Polyisocyanates are compounds having two or more isocyanate groups in one molecule, and examples thereof include chain aliphatic diisocyanates such as tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; aliphatic diisocyanates having a cyclic structure such as isophorone diisocyanate, hydrogenated xylylene diisocyanate, and dicyclohexylmethane 4,4'-diisocyanate; aliphatic diisocyanates having an aromatic ring such as xylylene diisocyanate and tetramethylxylylene diisocyanate; aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane diisocyanate; and modified products of these diisocyanates (carbodiimide-, uretdione-, and uretoimine-containing modified products, etc.). In the polyaddition reaction, a chain extender or a reaction terminator may be used in combination, if necessary. As the urethane resin, for example, an ester-based urethane resin, an ether-based urethane resin, or a carbonate-based urethane resin can be used.

[0013] The mass average molecular weight of the urethane resin is preferably 5,000 to 500,000. The average particle size of the urethane resin is preferably 30 to 200 nm, more preferably 50 to 100 nm. The glass transition temperature of the urethane resin is preferably from -60 to 160°C, more preferably from -20 to 140°C. The tensile strength of the urethane resin is preferably 3 to 80 MPa, and more preferably 20 to 70 MPa. The elongation of the urethane resin is preferably 5 to 1000%, and more preferably 10 to 600%.

[0014] The water-dispersible polyurethane may be produced by known chemical synthesis, or a commercially available product may be used. Examples of commercially available water-dispersible polyurethane products include the Takelac W series, such as Takelac W-6110 and Takelac W-6010, the Takelac WS series, such as Takelac WS-5100 and Takelac WS-4000 (all manufactured by Mitsui Chemicals, Inc.), the Baycusan series, such as Baycusan C1000 / 1 and Baycusan C1001 / 1 (all manufactured by Covestro Japan), the Superflex series (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), the Hydran HW series (manufactured by DIC Corporation), the Ymer series (manufactured by Perstorp), the Adeka Bontitor HUX series (manufactured by ADEKA Corporation), and the MELUSI series (manufactured by Toyo Polymer Co., Ltd.).

[0015] The content of component (A) in the antibacterial composition of the present invention is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of the ability to support the silver-based antibacterial agent, and is preferably 40% by mass or less, more preferably 10% by mass or less, from the viewpoint of the stability of the antibacterial composition.

[0016] The antibacterial composition of the present invention contains an aqueous dispersant as component (B). In this specification, the aqueous dispersant is one that disperses the water-dispersible polyurethane. Examples of the aqueous dispersant include water, alcohols having 1 to 4 carbon atoms diluted with water, etc. From the viewpoint of storage stability, water is preferred as the aqueous dispersant.

[0017] The content of component (B) in the antibacterial composition of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, from the viewpoints of dispersing component (A) and antibacterial effect.

[0018] The mass ratio of component (A) to component (B) [(B) / (A)] in the antibacterial composition of the present invention is preferably 10 or more, more preferably 30 or more, from the viewpoint of dispersibility of component (A).

[0019] The antibacterial composition of the present invention contains a silver-based antibacterial agent as component (C). Examples of silver-based antibacterial agents include silver-based inorganic antibacterial agents in which silver ions are supported on a carrier, silver compounds such as silver oxide and silver nitrate, and silver complexes. Examples of carriers for supporting silver ions include silicate-based agents such as zeolite, phosphate-based agents such as calcium phosphate and zirconium phosphate, and glass-based agents such as soluble glass. Note that, in this specification, silver nanoparticles are not included in the silver-based antibacterial agents. One or more types of silver-based antibacterial agents can be used. Among these, from the viewpoint of dispersibility, the silver-based antibacterial agent is preferably one or more selected from silver-based inorganic antibacterial agents and silver oxide, more preferably silver oxide.

[0020] The silver-based antibacterial agent may be produced by a known method, or a commercially available product may be used. Examples of commercially available silver-based antibacterial agents include silver oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and silver-based inorganic antibacterial agents such as those using a zeolite carrier, such as Zeomic (manufactured by Sinanen Holdings Co., Ltd.) and Silica Join 1z (manufactured by Aichi Sodium Dioxide Industries Co., Ltd.), those using a glass carrier, such as Ion Pure (manufactured by Ishizuka Glass Co., Ltd.) and Silica Join 5G (manufactured by Aichi Sodium Dioxide Industries Co., Ltd.), those using a calcium phosphate carrier, such as the Apacider series, such as Apacider AW (manufactured by Sangi Co., Ltd.), those using a zirconium phosphate carrier, such as the Novalon series, such as Novalon AG300 (manufactured by Toagosei Co., Ltd.), those using a silicate carrier, such as Ceramedic (manufactured by Sinanen Holdings Co., Ltd.), and silver-zinc composite particles, such as Amteclean z (manufactured by Panasonic Industries Co., Ltd.).

[0021] From the viewpoint of the antibacterial effect of the surface obtained through the surface treatment, the average particle size of component (C) is preferably 1 μm or more in volume average particle size. In the treated film in which silver oxide was mixed with the water-dispersible polyurethane of the present invention shown in the Examples below, the average film thickness of component (A) was approximately 270 nm, while silver nanoparticles, by definition, have a particle size of 100 nm or less. Therefore, nanoparticles may be embedded inside the coated film and lose the opportunity to contact the bacterial cells. On the other hand, if a silver-based antibacterial agent has a volume average particle size of 1 μm or more, component (C) is always exposed on the coated film, which is thought to ensure antibacterial properties. The volume average particle size of component (C) is more preferably 1 μm or more and 100 μm or less, and even more preferably 1 μm or more and 50 μm or less, from the viewpoint of the antibacterial effect on the surface obtained through the surface treatment, and taking into consideration operability, dispersibility in liquid, etc. In this specification, the volume average particle size of component (C) can be measured by the method described in the Examples below.

[0022] The content of component (C) in the antibacterial composition of the present invention can be appropriately set depending on the type, but from the viewpoint of antibacterial activity, it is preferably 0.001 mass% or more, more preferably 0.01 mass% or more, and even more preferably 0.03 mass% or more.

[0023] From the viewpoint of antibacterial properties, the mass ratio of component (A) to component (C) [(C) / (A)] in the antibacterial composition of the present invention is preferably 0.01 or more, more preferably 0.03 or more, and even more preferably 0.1 or more.

[0024] In addition to the above components, the antibacterial composition of the present invention may contain an appropriate combination of additives, such as surfactants, polymers, chelating agents, moisturizing agents, lubricants, builders, buffers, abrasives, electrolytes, bleaching agents, fragrances, dyes, foam control agents, corrosion inhibitors, essential oils, thickeners, pigments, gloss enhancers, enzymes, detergents, dispersants, silicones, hydrotropic substances, etc., within a range that does not impair the effects of the present invention. The content of the additives can be appropriately set within a range that does not impair the object of the present invention.

[0025] The antibacterial composition of the present invention can be produced by any suitable method. For example, it can be produced by mixing components (A), (B), and (C), and, if necessary, other components. The order in which the components are mixed is not particularly limited, and they can be mixed in any order. However, from the viewpoint of dispersing component (A), it is preferable to mix components (A) and (B) first, and then mix component (C).

[0026] The antibacterial composition of the present invention may be in a liquid or gel form, but is preferably in a liquid form. When the antibacterial composition is in a gel form, it can be prepared by appropriately adding a natural or synthetic gelling agent, for example, a water-soluble gelling agent such as carrageenan or gellan gum, or an oil-soluble gelling agent such as metal soap or aluminum octylate, according to a conventionally known method.

[0027] As shown in the examples below, surface treatment using a composition containing a water-dispersible polyurethane, an aqueous dispersant, and a silver-based antibacterial agent forms a treated film that is highly water-resistant and scratch-resistant and exhibits excellent antibacterial effects against a variety of microorganisms, including gram-positive and gram-negative bacteria, such as Staphylococcus aureus, Enterococcus faecium, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Therefore, the combination of the water-dispersible polyurethane, the water-based dispersant, and the silver-based antibacterial agent can be an active ingredient of an antibacterial composition, and can be used to produce an antibacterial composition. Furthermore, by applying a composition containing a water-dispersible polyurethane, a water-based dispersant, and a silver-based antibacterial agent to a target surface, antibacterial properties can be imparted to the target surface.

[0028] The antibacterial composition of the present invention can be applied to a variety of microorganisms, including gram-positive bacteria, gram-negative bacteria, and drug-resistant strains thereof. Examples of Gram-positive bacteria include Bacillus bacteria such as Bacillus subtilis, Bacillus anthracis, and Bacillus cereus; Listeria bacteria such as Listeria monocytogenes, Listeria ivanovii, and Listeria seeligeri; Alicyclobacillus bacteria such as A. acidoterrestris (formerly B. acidoterrestris); Staphylococcus bacteria such as S. aureus (Staphylococcus aureus); and Streptococcus bacteria such as S. pyogenes. Examples of bacteria include Clostridium bacteria such as C. botulinum, C. perfringens, and C. sporogenes; Clostridioides bacteria such as C. difficile; Leuconostoc bacteria such as L. mesenteroides; Desulfotomaculum bacteria such as D. nigrificans; Enterococcus bacteria such as E. faecalis, E. faecium, E. gallinarum, and E. casseriflavus; and Streptococcus bacteria such as S. pneumoniae. Examples of Gram-negative bacteria include Shigella bacteria such as S. dysenteriae (Shigella subgroup A), S. flexneri (Shigella subgroup B), S. boydii (Shigella subgroup C), and S. sonnei (Shigella subgroup D); Brucella bacteria; Escherichia coli such as E. coli O157; S. typhi (Salmonella typhi), S. paratyphi A (Salmonella paratyphi A), and S. paratyphi Examples of bacteria that may be present include Salmonella bacteria such as Salmonella paratyphi B, S. Typhimurium, and S. Enteritidis; Vibrio bacteria such as V. cholerae and V. parahaemolyticus; Pseudomonas bacteria such as P. aeruginosa; Acinetobacter bacteria such as A. baumannii; Klebsiella bacteria such as K. pneumoniae; Stenotrophomonas bacteria such as S. maltophilia; and Enterobacter bacteria such as E. cloacae. Drug-resistant bacteria include bacteria that are resistant to specific or multiple antibacterial drugs, such as MRSA (methicillin-resistant Staphylococcus aureus), PRSP (penicillin-resistant Streptococcus pneumoniae), VRE (vancomycin-resistant Enterococcus), extended-spectrum beta-lactamase (ESBL)-producing bacteria, AmpC-producing bacteria, MDRP (multidrug-resistant Pseudomonas aeruginosa), CRE (carbapenem-resistant Enterobacteriaceae), CPE (carbapenemase-producing Enterobacteriaceae), and MDRA (multidrug-resistant Acinetobacter). In particular, the present invention is suitable for Staphylococcus bacteria, coliform bacteria (Escherichia coli), Enterococcus bacteria, Klebsiella bacteria, Acinetobacter bacteria, Pseudomonas bacteria, and Enterobacter bacteria.

[0029] In the present invention, "antibacterial" is a term that includes the concepts of "sterilization" and "sterilization" that kill microorganisms, and "bacteriostasis" and "bacteriostatic" that suppress the occurrence, growth, and proliferation of microorganisms.

[0030] The antibacterial composition of the present invention can be applied to surfaces such as the skin or mucous membranes of animals to which bacteria adhere, and hard or soft surfaces of inanimate objects. In particular, the antibacterial composition is particularly suitable for hard or soft surfaces of inanimate objects. Examples of inanimate surfaces include hard surfaces such as counters, sinks, restrooms, washbasins, toilets, bathtubs, shower basins, floors, windows, doorknobs, walls, drains, faucets, and pipes in homes, hospitals, and other commercial facilities; hard surfaces such as handrails and tables; kitchen utensils, furniture, telephones, personal computers, calculators, air purifiers, humidifiers, medical equipment, buttons on various devices, and various tools, tools, miscellaneous goods, and stationery; and soft surfaces such as textile products (carpets, area rugs, curtains, bedding, fabric furniture, clothing, masks, and the like).

[0031] The mode of applying the antibacterial composition of the present invention to a target surface is not particularly limited, and any of a method of directly applying the antibacterial composition to the target to be treated, a method of diffusing the antibacterial composition and sprinkling it on the target to be treated, and a method of wiping the target surface with a sheet, gauze, towel, wet towel, tissue, wet tissue, or the like impregnated with the antibacterial composition may be used. Another method is to fill the antibacterial composition into a known spray container, such as a trigger spray container (direct pressure or pressure-accumulating type), a dispenser-type pump spray container, or an aerosol spray container equipped with a pressure-resistant container, and spray the composition onto the target to be treated by appropriately adjusting the spray amount. Among these, since the treated film formed by the antibacterial composition of the present invention has abrasion resistance, a method in which the antibacterial composition is impregnated into a sheet and the target surface is wiped with the sheet is preferred.

[0032] After applying the antibacterial composition to a target surface, it is preferable to leave it to dry. For example, it is preferable to leave it for 30 minutes or more in a wet area such as a sink. This allows the formation of a treatment film on the target surface that has high water resistance, abrasion resistance, and antibacterial properties. In such a treated film, the average film thickness formed by component (A) is preferably 200 nm or more from the viewpoints of water resistance and antibacterial agent carrying capacity. In this specification, the average film thickness formed by component (A) can be calculated from the mass per unit area and density of component (A).

[0033] The amount of the antibacterial composition of the present invention to be used can be adjusted appropriately depending on the treatment mode, spatial environment such as temperature and humidity, etc., but is preferably 25 g / m 2 That's all. [Example]

[0034] [Measuring particle size of silver oxide] The particle size distribution analyzer used was the LA-950V2 (manufactured by HORIBA). Silver oxide (manufactured by Fujifilm Wako Pure Chemical Industries) was dispersed in ion-exchanged water using the wet method, and measurements were taken while circulating the water. Measurements were performed with N=5, and data was obtained as a volume distribution. The maximum and minimum values ​​were removed, and the average value of the median diameters of the three points (d1, d2, d3) was taken as the volume-average particle size.

[0035] Test example: Antibacterial test The ingredients used in the examples are summarized below. Anionic self-emulsifying polyurethane 1: Takelac (registered trademark) W-6110 (active ingredient 32%), Anionic self-emulsifying polyurethane 2: Takelac W-6010 (active ingredient 30%), Anionic self-emulsifying polyurethane 3: Takelac WS-5100 (active ingredient 30%), Anionic self-emulsifying polyurethane 4: Takelac WS-4000 (active ingredient 30%). All manufactured by Mitsui Chemicals. The original solution was diluted to 5% with ion-exchanged water, and this was used appropriately as a stock dispersion. Silver oxide: Fujifilm Wako Pure Chemical Industries AgNPs (silver nanoparticles): Merck, product number 807044. 80 nm average part size, 1 mg / mL (aqueous sodium citrate), citrate functionalized

[0036] <Creating test specimens> 130 μL of each composition was applied to the transparent portion (61 × 26 mm) of a slide glass (MATSUNAMI Co., Ltd., Superfrost slide glass 76 × 26 mm S2441) and air-dried at room temperature. After drying, the surface was washed with sterilized deionized water and then air-dried again at room temperature. On the other hand, a substrate without any coating was used as a control.

[0037] <Water resistance test treatment> A sterile 200 mL screw cup (manufactured by Eiken Chemical Co., Ltd.) was filled with 200 mL of ion-exchanged water, and the test specimen obtained in the above <Preparation of test specimen> was immersed in it, and while holding the white part of the slide glass, it was shaken for 5 seconds to wash it. This was repeated 10 times per test specimen, and then it was air-dried at room temperature.

[0038] <Treatment for abrasion resistance test> NW-ASP-40KS (manufactured by Daiwabo) was cut into 2 cm x 2 cm pieces to prepare a dry sheet and a wet sheet with a moisture content of 100% by weight. The dry sheet and then the wet sheet were moved back and forth over the test piece obtained in the above <Preparation of Test Pieces>, in that order, for a total of three cycles of contact, resulting in a rubbing treatment. The moisture adhering to the wet sheet due to contact was removed by air drying at room temperature, and then the test was conducted.

[0039] <Antibacterial test> [Preparation of bacterial solution] The following bacterial cells were used as test samples: Table 1 shows a list of the bacteria used in the antibacterial tests.

[0040] [Table 1]

[0041] The glycerol stock solutions stored at -80°C in Table 1 were pre-cultured at 37°C for 24 hours using Soybean Casein Digest Agar (Nihon Pharmaceutical Co., Ltd., SCD agar medium "Daigo") The next day, colonies were picked and streaked onto new SCD agar medium, and cultured at 37°C for 24 hours. The next day, the colonies were suspended in sterile saline, and the absorbance at a wavelength of 600 nm (OD600nm) was measured using a spectrophotometer (Hitachi High-Technologies Corporation, U-5100), and the suspension was adjusted to an OD of 1. This was diluted 100-fold with Soybean Casein Digest Broth (Nihon Pharmaceutical Co., Ltd., SCD medium "Daigo") to prepare the bacterial solution for evaluation.

[0042] [Contact between bacterial solution and treated surface] A drop of 100 μL of bacterial suspension was placed on each test specimen, sandwiched between two test specimens treated with the same agent, and placed in a sterile No. 2 square Petri dish (140 × 100 × 14.5 mm, Eiken Chemical Co., Ltd.) and incubated at 32.5°C for 24 hours. The slides sandwiching the bacterial suspension were washed with sterile ion-exchanged water using a 5 mL pipette, with the bacterial suspension surface exposed. The surface of the test specimen was swabbed using a Fukifuki Check II (Eiken Chemical Co., Ltd.), and the container was vortexed for 30 seconds to suspend the bacterial cells. This was then serially diluted 10-fold to prepare bacterial suspension, and 3 μL was added to SCD agar medium in a sterile No. 2 square Petri dish and incubated at 37°C for 18 to 24 hours. In addition, 50 μL of the original suspension was added to SCD agar medium filled in a sterile petri dish (Φ90 x 15 mm: manufactured by Ina Optica) so that the detection limit could be confirmed down to 1.313 [log (cfu / mL)]. The antibacterial activity value was calculated by the following method. Antibacterial activity value = log {(number of viable bacteria on untreated test specimen after 24 hours of incubation) - (number of viable bacteria on treated test specimen after 24 hours of incubation)}

[0043] Figure 1 shows the results of measuring the particle size of silver oxide. The average particle size was 29.80 ± 1.37 μm. Table 2 shows the results of antibacterial tests on S. aureus and E. coli when they were brought into contact with test pieces treated for water resistance testing. Table 3 shows the results of an antibacterial test comparing silver oxide and silver nanoparticles as antibacterial agents. Table 4 shows the results of an antibacterial test on test pieces also treated for water resistance testing, to determine the minimum concentration limit of the antibacterial agent used. Table 5 shows the results of an antibacterial test on test pieces treated for abrasion resistance testing when they were brought into contact with bacterial cells. Table 6 shows the results of an antibacterial test targeting a combination of multiple drug-resistant or susceptible bacteria.

[0044] [Table 2-1]

[0045] [Table 2-2]

[0046] [Table 2-3]

[0047] [Table 3]

[0048] [Table 4-1]

[0049] [Table 4-2]

[0050] [Table 4-3]

[0051] [Table 5]

[0052] [Table 6]

[0053] <Result> As shown in Tables 2, 4-6, treated films in which silver oxide was mixed with water-dispersible polyurethane exhibited a significant antibacterial effect against both gram-positive and gram-negative bacteria, and both drug-resistant and drug-susceptible bacteria. On the other hand, when water-dispersible polyurethane was used for surface treatment without the addition of an antibacterial agent, no reduction in bacterial counts was observed. Furthermore, as shown in Table 3, water-dispersible polyurethane exhibited a significant antibacterial effect when silver oxide was used as a silver-based antibacterial agent, while the antibacterial effect decreased when silver nanoparticles were added. This confirmed that the antibacterial properties of the treated surface can be ensured by mixing water-dispersible polyurethane with a silver-based antibacterial agent.

Claims

1. The following components (A), (B), and (C): (A) Water-dispersible polyurethane (B) Aqueous dispersant (C) Silver-based antibacterial agent An antibacterial composition comprising:

2. 2. The antibacterial composition according to claim 1, wherein the content of component (A) is 0.01% by mass or more and 40% by mass or less.

3. 2. The antibacterial composition according to claim 1, wherein the content of component (B) is 50% by mass or more.

4. 2. The antibacterial composition according to claim 1, wherein the content of component (C) is 0.001% by mass or more.

5. 5. The antibacterial composition according to claim 1, wherein the component (A) is an anionic self-emulsifying polyurethane.

6. 5. The antibacterial composition according to claim 1, wherein component (B) is an aqueous dispersant containing water or a water-diluted alcohol having 1 to 4 carbon atoms.

7. 5. The antibacterial composition according to claim 1, wherein component (C) is at least one selected from silver oxide and silver-based inorganic antibacterial agents.

8. The antibacterial composition according to any one of claims 1 to 4, wherein the volume average particle size of component (C) is 1 µm to 100 µm.

9. The antibacterial composition according to any one of claims 1 to 4, which is effective against microorganisms including drug-resistant bacteria.

10. 10. The antibacterial composition according to claim 9, wherein the microorganism is selected from the group consisting of Staphylococcus bacteria, Escherichia coli, Enterococcus bacteria, Klebsiella bacteria, Acinetobacter bacteria, Pseudomonas bacteria and Enterobacter bacteria.

11. A treated film formed on a target surface using the antibacterial composition according to any one of claims 1 to 4.

12. An antibacterial sheet impregnated with the antibacterial composition according to any one of claims 1 to 4.

13. An antibacterial method, comprising applying the antibacterial composition according to any one of claims 1 to 4 to a target surface.

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