Antimicrobial metal materials and antimicrobial articles

Abstract

The antimicrobial metal material has a surface with a roughness index of 4.0 or higher. The roughness index is obtained by dividing the true surface area (m²) measured by the krypton adsorption method by the geometric surface area (m²).

Description

Technology Field

[0001] The present disclosure relates to antimicrobial metal materials and antimicrobial articles. Background Technology

[0002] There is a growing demand for antimicrobial articles having antimicrobial properties in many applications, including pharmaceuticals, medical care, and housing. For example, Patent Document 1 discloses an antimicrobial article having an antimicrobial resin film. The antimicrobial article disclosed in Patent Document 1 comprises an antimicrobial resin film containing a specific polymer and a substrate to which the antimicrobial resin film is bonded. Prior art literature

[0003] International Publication No. 2016 / 051444 The problem to be solved

[0004] In the technology described in Patent Document 1, there is a possibility that the antimicrobial resin film may peel off from the substrate, and there is a concern that chemical substances contained in the antimicrobial resin film may leach out. There is also a possibility that the antimicrobial properties of the antimicrobial resin film may not be sufficient.

[0005] The present disclosure is made in consideration of these circumstances, and the problem to be solved by one embodiment of the present disclosure is to provide an antimicrobial metal material with excellent antimicrobial properties.

[0006] The problem that another embodiment of the present disclosure aims to solve is to provide an antimicrobial article using the antimicrobial metal material. means of solving the problem

[0007] The present disclosure includes the following aspects.

[0008] <1> An antimicrobial metal material having a surface with a roughness index of 4.0 or higher, obtained by dividing the true surface area (m²) measured by the krypton adsorption method by the geometric surface area (m²).

[0009] <2> The above surface has a porous structure, the above <1> Antimicrobial metal material as described in

[0010] <3> having a plating layer,

[0011] The above surface is the surface of the plating layer, the <2> Antimicrobial metal material as described in

[0012] <4> The structure having a diameter of at least some of the openings of a plurality of holes smaller than the maximum inner diameter of the hole <2> or <3> Antimicrobial metal material as described in

[0013] <5> The above surface satisfies at least one of (1) to (3) below, the above <2> inside <4> Antimicrobial metal material described in any one of the

[0014] (1) The average value of the arithmetic mean roughness (Ra) is 0.2㎛ to 20㎛.

[0015] (2) The average value of the 10-point average roughness (Rz) is 2㎛ to 100㎛.

[0016] (3) Average length of roughness curve elements (RS m The average value of ) is 10㎛ to 400㎛.

[0017] <6> The average value of the above arithmetic mean roughness (Ra) is 3㎛ or more, and

[0018] The average value of the above 10-point average roughness (Rz) is 20㎛ or more, and

[0019] Average length (RS) of the above roughness curve elements m The above, wherein the average value of ) is 100㎛ or more <5> Antimicrobial metal material as described in

[0020] <7> The above surface has an uneven structural layer with an average thickness of 10 nm to 5000 nm. <1> inside <6> Antimicrobial metal material described in any one of the

[0021] <8> The above uneven structural layer is a dendritic layer or a mesh layer, the <7> Antimicrobial metal material as described in

[0022] <9> The above, having an average thickness of more than 200 nm, <7> or <8> Antimicrobial metal material as described in

[0023] <10> The above, having an average thickness of 350 nm or more, <7> or <8> Antimicrobial metal material as described in

[0024] <11> It comprises at least one selected from the group consisting of aluminum, magnesium, silver, copper, iron, titanium, alloys, and plating materials, and

[0025] The above alloy comprises at least one selected from the group consisting of aluminum, magnesium, silver, copper, iron, and titanium, the <1> inside <10> Antimicrobial metal material described in any one of the

[0026] <12> The above roughness index is 95.0 or higher, the above <1> inside <11> Antimicrobial metal material described in any one of the

[0027] <13> The above <1> inside <12> Antimicrobial article comprising an antimicrobial metal material described in any one of the following. Effects of the invention

[0028] According to one embodiment of the present disclosure, an antimicrobial metal material with excellent antimicrobial properties is provided.

[0029] According to another embodiment of the present disclosure, an antimicrobial article using the antimicrobial metal material is provided. Brief explanation of the drawing

[0030] Figure 1 is a cross-sectional view schematically showing an example of a dendritic layer of an antibacterial metal material. Specific details for implementing the invention

[0031] In the present disclosure, a numerical range indicated by "to" represents a range that includes the values ​​described before and after "to" as the minimum and maximum values, respectively.

[0032] In the numerical ranges described stepwise in the present disclosure, an upper or lower limit value described in any numerical range may be substituted with an upper or lower limit value of a numerical range described stepwise, or may be substituted with a value shown in the examples.

[0033] In the present disclosure, the amount of each component in the material refers to the total amount of the multiple substances present in the material, unless specifically stated otherwise, in cases where multiple substances corresponding to each component in the material exist.

[0034] In the present disclosure, the term “process” is included not only in independent processes but also in cases where it cannot be clearly distinguished from other processes, provided that the intended purpose of the process is achieved.

[0035] In describing embodiments with reference to the drawings in this disclosure, the configuration of said embodiment is not limited to the configuration shown in the drawings. The sizes of the components in each drawing are conceptual, and the relative relationships of sizes between components are not limited thereto.

[0036] Antimicrobial Metal Materials

[0037] The antimicrobial metal material according to the present disclosure has a surface having a roughness index of 4.0 or higher, which is obtained by dividing the true surface area (m²) measured by the krypton adsorption method by the geometric surface area (m²). Accordingly, the antimicrobial metal material exhibits excellent antimicrobial properties.

[0038] When describing the antimicrobial metal material according to the present disclosure, "antimicrobial" means having at least one of antimicrobial performance and virus inactivation performance. In the present disclosure, "microbial" is a concept that includes bacteria and viruses.

[0039] Bacteria exhibiting antibacterial performance by the antimicrobial metal material of the present disclosure include Staphylococcus aureus. Viruses exhibiting virus inactivation performance by the antimicrobial metal material of the present disclosure include Influenza A H3N2 and feline calicivirus. Hereinafter, based on the presumed mechanism below, bacterial species exhibiting antibacterial performance are not limited to Staphylococcus aureus, and virus species exhibiting virus inactivation performance are not limited to Influenza A H3N2 and feline calicivirus.

[0040] The antimicrobial metal material of the present disclosure comprises a first configuration and a second configuration. The first configuration consists solely of a member made of a metal or alloy as described below. The second configuration comprises a member made of a metal or alloy and a plating layer laminated thereon. In the case of the first configuration, the "surface" of the antimicrobial metal material refers to the surface of the member made of a metal or alloy. In the case of the second configuration, the "surface" of the antimicrobial metal material refers to the surface of the plating layer.

[0041] Although the mechanism by which the antimicrobial metal material exhibits excellent antimicrobial properties by setting the surface roughness index (hereinafter also simply referred to as "roughness index") of the antimicrobial metal material to 4.0 or higher is not clear, it is estimated as follows.

[0042] The surface of an antimicrobial metal material with a roughness index of 4.0 or higher has a fine uneven structure. Therefore, when bacteria are attached to the surface of the antimicrobial metal material (i.e., the uneven structure), the bacteria are damaged by the uneven structure, and in a preferred embodiment, the bacteria are killed.

[0043] It is believed that when a virus attaches to the uneven structure of an antimicrobial metal material, at least a portion of the virus is captured in the uneven structure, the activity of the virus is weakened, and in a preferred embodiment, the virus is inactivated.

[0044] The scope of the present disclosure is not limited in any way by the above assumption.

[0045] As described in detail below, an antimicrobial metal material can be manufactured by performing a surface treatment on the surface of the metal material, and a fine uneven structure is formed on the surface of the metal material by the surface treatment. That is, an uneven structure having antimicrobial properties is formed by surface treatment of the metal material itself. Therefore, peeling as described above does not occur with respect to the technology described in Patent Document 1 using an antimicrobial resin film, and the leaching of chemical substances is suppressed. Furthermore, in a mode in which the antimicrobial properties of the metal itself are exhibited, the antimicrobial properties of the antimicrobial metal material can be further enhanced.

[0046] From the perspective of further enhancing antibacterial properties, a roughness index of 10.0 or higher is desirable, 25.0 or higher is more desirable, 50.0 or higher is even more desirable, and 95.0 or higher is particularly desirable. When the roughness index is 95.0 or higher, the antibacterial performance against Staphylococcus aureus and the virus inactivation performance against Influenza A H3N2 are superior, and in a relatively short time (e.g., after 30 minutes have passed since inoculation of bacteria or viruses), Staphylococcus aureus can be further damaged, and the activity of Influenza A H3N2 and feline calicivirus can also be weakened. As a result, the antibacterial properties of the antibacterial metal material are superior, and the immediate effect is also excellent.

[0047] The upper limit of the roughness index is not specifically restricted, but from the perspective of increasing antibacterial properties, it may be 150.0 or less, 125.0 or less, or 110.0 or less.

[0048] In the present disclosure, the true surface area is a value calculated by multiplying the specific surface area (m² / g) of a sample (i.e., an antimicrobial metal material) obtained by the krypton adsorption method by the mass of the sample.

[0049] The specific surface area is determined by the BET method after vacuum heating and degassing the sample (antimicrobial metal material) at 100°C, measuring the adsorption isotherm using the krypton adsorption method at a liquid nitrogen temperature (77°K), and then measuring the adsorption isotherm. The adsorption isotherm can be measured using a gas adsorption amount measuring device. For example, BELSORP-max (manufactured by Microtrack Bel Co., Ltd.) may be used as the gas adsorption amount measuring device.

[0050] As the mass of the antimicrobial metal material, the mass of the metal material after the glazing treatment may be used. Since the change in mass before and after the glazing treatment is very small, the mass of the metal material before the glazing treatment may be used as the mass of the antimicrobial metal material.

[0051] In the present disclosure, the geometric surface area is a value obtained from the dimensions of the object to be measured. For example, if the object to be measured is a rectangular prism with length X, width Y, and height Z, the geometric surface area S is obtained as S = 2XY + 2YZ + 2ZX.

[0052] The object of geometric surface area measurement is the surface of part or all of the antimicrobial metal material.

[0053] The subject for measuring the geometric surface area may be a metal material after the harmonic treatment. Since the change in geometric surface area before and after the harmonic treatment is very small, the subject for measuring the geometric surface area may be a metal material before the harmonic treatment.

[0054] The types of metals included in the antimicrobial metal material are not particularly limited. Examples of metals include, for instance, aluminum, iron, copper, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, zirconium, titanium, niobium, chromium, aluminum, magnesium, manganese, alloys containing the said metals, etc., and plating materials of said metals and said alloys.

[0055] For example, the antimicrobial metal material may include at least one selected from the group consisting of aluminum, magnesium, silver, copper, iron, titanium, alloys, and plating materials. The alloy includes at least one selected from the group consisting of aluminum, magnesium, silver, copper, iron, and titanium. The alloy may include aluminum, magnesium, silver, copper, iron, and titanium as main components. The term "main component" indicates that the proportion of aluminum, magnesium, silver, copper, iron, and titanium is 50 mass% or more with respect to the total amount of the alloy. The plating material includes aluminum, magnesium, copper, iron, titanium, and the above alloys.

[0056] In particular, silver and copper can further enhance the antibacterial properties of antibacterial materials due to their own antibacterial properties.

[0057] Examples of the above alloys include brass, phosphor bronze, steel (e.g., stainless steel), brass, etc. Examples of the above plating materials include plated steel, etc.

[0058] The surface of the antimicrobial metal material may have a porous structure (hereinafter referred to as the "first microstructure").

[0059] In the present disclosure, "porous structure" refers to a structure having a plurality of holes. More specifically, "porous structure" refers to a structure in which holes exist when observing a cross-section obtained by cutting the antimicrobial metal material horizontally with respect to the surface of the antimicrobial metal material.

[0060] In the present disclosure, "hole" means an open pore (a hole connected to the outside air). The hole diameter is a value measured at the entrance of the hole.

[0061] The porous structure can be confirmed by observing the surface of the antimicrobial metal material and cross-sections perpendicular to the surface using an electron microscope or a laser microscope.

[0062] The antimicrobial metal material preferably has a plating layer, and the surface of the porous structure is the surface of the plating layer. Examples of materials for the plating layer include zinc, nickel, and chromium.

[0063] Below, a plating layer with a porous surface structure is sometimes referred to as a "porous plating layer."

[0064] The antimicrobial metal material may have a porous structure in which the diameter of at least some of the openings of a plurality of holes is smaller than the maximum inner diameter of the holes (hereinafter referred to as a “specific structure”). By doing so, it may be easier to increase the antimicrobial properties of the antimicrobial metal material.

[0065] In the present disclosure, the “diameter of the opening” of a hole is a value measured at the entrance of the hole.

[0066] Specific structures can be identified by observing a cross-section perpendicular to the surface of the antimicrobial metal material using an electron microscope or a laser microscope.

[0067] In addition to having a porous structure, the surface of the antibacterial metal material may satisfy at least one of the following (1) to (3).

[0068] (1) The average value of the arithmetic mean roughness (Ra) is 0.2㎛ to 20㎛.

[0069] (2) The average value of the 10-point average roughness (Rz) is 2㎛ to 100㎛.

[0070] (3) Average length of roughness curve elements (RS m The average value of ) is 10㎛ to 400㎛.

[0071] By imparting such a harmonized surface to the antimicrobial metal material, it can be made easier to enhance the antimicrobial properties of the antimicrobial metal material.

[0072] Below are the average values ​​of the arithmetic mean roughness (Ra), the 10-point average roughness (Rz), and the average lengths of the roughness curve elements (RSm There are cases where the average value of ) is combined and referred to as "macroscopic surface characteristics."

[0073] The arithmetic mean roughness (Ra) is a value measured in accordance with JIS B 0601: 2001 (corresponding international standard: ISO 4287).

[0074] The average value of the arithmetic mean roughness (Ra) may be 0.2 μm to 10 μm, 0.3 μm to 7 μm, or 3 μm to 6 μm.

[0075] The 10-point average roughness (Rz) is a value measured in accordance with JIS B 0601: 2001 (corresponding international standard: ISO 4287).

[0076] The average value of the 10-point average roughness (Rz) may be 5㎛ to 100㎛, 6㎛ to 80㎛, 8㎛ to 50㎛, or 20㎛ to 35㎛.

[0077] Average length of roughness curve elements (RS m ) is a value measured in accordance with JIS B 0601: 2001 (corresponding international standard: ISO 4287).

[0078] Average length of roughness curve elements (RS m The average value of ) may be 50㎛ to 350㎛, 80㎛ to 250㎛, 90㎛ to 150㎛, or 100㎛ to 130㎛.

[0079] Among them, the surface of the antimicrobial metal material has an average value of arithmetic mean roughness (Ra) of 3㎛ or more, an average value of 10-point average roughness (Rz) of 20㎛ or more, and an average length of roughness curve elements (RS mIt is preferable that the average value of ) be 100㎛ or more. Accordingly, in the antimicrobial metal material, the antimicrobial performance against Staphylococcus aureus and the virus inactivation performance against Influenza A H3N2 are superior, and it is possible to damage Staphylococcus aureus and weaken the activity of Influenza A H3N2 and feline calicivirus in a relatively short time (e.g., after 30 minutes have passed since inoculation of bacteria or viruses). As a result, the antimicrobial properties of the antimicrobial metal material are superior, and the immediate effect is also excellent.

[0080] The surface of the antimicrobial metal material may have an uneven structural layer with an average thickness of 10 nm to 5000 nm (hereinafter referred to as the "second microstructure"). By imparting such a textured surface to the antimicrobial metal material, it may be easier to increase the antimicrobial properties of the antimicrobial metal material.

[0081] The average thickness of the second microstructure may be 20 nm or more and less than 4000 nm, 30 nm to 2000 nm, 50 nm to 800 nm, 100 nm to 700 nm, 150 nm to 600 nm, more than 200 nm and less than or equal to 600 nm, or 350 nm to 600 nm.

[0082] If the average thickness of the second microstructure exceeds 200 nm, the antimicrobial metal material exhibits superior antimicrobial performance against Staphylococcus aureus and superior virus inactivation performance against Influenza A H3N2, and can damage Staphylococcus aureus and weaken the activity of Influenza A H3N2 and feline calicivirus in a relatively short time (e.g., after 30 minutes following inoculation of bacteria or viruses). As a result, the antimicrobial properties of the antimicrobial metal material are superior, and the immediate effect is also excellent.

[0083] If the average thickness of the second microstructure is 350 nm or more, the antibacterial performance against Staphylococcus aureus in the antibacterial metal material is excellent, and the immediate effect is also excellent, compared to when the average thickness of the second microstructure is greater than 200 nm and less than 350 nm.

[0084] The average thickness of the second microstructure is calculated from a cross-sectional profile obtained by a scanning electron microscope (SEM). Specifically, using a scanning electron microscope (SEM), SEM images are taken for 10 randomly selected points on an antimicrobial metal material, and for each image, the average thickness at a length of 1 μm is measured for any 2 spots, and similar measurements are performed for the other 9 points. Then, the average value of the total 20 measurements is called the average thickness of the second microstructure.

[0085] The second microstructure (i.e., the uneven structure layer) may be a dendritic layer, a mesh layer (sometimes referred to as a "spongy layer"), or a needle-like layer. This makes it easier to increase the antibacterial properties of the antibacterial metal material.

[0086] A dendritic layer refers to a layer in which stems originating from the metal material portion that has undergone shaping treatment are formed from the surface of the metal material. The stems may have branches that are divided from the stems, and the branches may have lateral branches that are divided from the branches.

[0087] A mesh layer refers to a layer having a mesh-like or sponge-like shape originating from a metal material part that has undergone a polishing treatment.

[0088] The needle-shaped upper layer refers to a layer having sharp and irregular shapes originating from the plated part where the polishing treatment was performed.

[0089] The dendritic layer or mesh layer may be an aluminum oxide layer or an aluminum hydroxide layer. From the perspective of extending the lifespan of surface irregularities of a metal material in a high-temperature and high-humidity environment, it is preferable that the second microstructure includes a dendritic layer made of aluminum oxide.

[0090] An antibacterial metal material (100), which is an example of the antibacterial metal material of the present disclosure, is shown in FIG. 1.

[0091] The antibacterial metal material (100) may be one in which a dendritic layer (30) is formed on the surface of the metal material (10), for example, as shown in FIG. 1.

[0092] The dendritic layer and the reticular layer can be identified by observing the surface and cross-sections perpendicular to the surface of the antimicrobial metal material using an electron microscope or a laser microscope.

[0093] With the above configuration, the antimicrobial metal material can have various structures. For example, the surface of the antimicrobial metal material may have only a porous structure (first microstructure), only an uneven structure layer (second microstructure), or both the first microstructure and the second microstructure.

[0094] For example, the surface of the antimicrobial metal material has a porous structure, and in the porous structure (first microstructure), a fine uneven structure layer (second microstructure) may be further provided on at least one side of the inner and outer sides of the hole. By doing so, it may be easier to further enhance the antimicrobial properties of the antimicrobial metal material.

[0095] For example, the surface of the antimicrobial metal material may have a porous structure and a dendritic layer (second microstructure) may be formed on at least one side of the inner and outer sides of the pores. In this case, the antimicrobial metal material is, for example, Ra of 4 μm to 6 μm, Rz of 20 μm to 35 μm, and RS of 90 μm to 120 μm. mIt may have a porous structure having at least one of the following, and an uneven structure layer with an average thickness of several nanometers to several hundred nanometers. By doing so, it may be easier to further increase the antibacterial properties of the antibacterial metal material.

[0096] Presence or absence of porous structure (first microstructure), presence or absence of specific structure, range of Ra, range of Rz, RS m It is desirable to appropriately select the range, the presence or absence and thickness of the second microstructure, and the presence or absence of the dendritic layer depending on the type of bacteria and viruses targeted for antibacterial activity. For example, bacteria are approximately several hundred nanometers to several tens of micrometers in size, and viruses are several nanometers to several hundred nanometers in size. Taking these sizes into account, it is desirable to control the surface structure of the antibacterial metal material (i.e., the presence or absence of a porous structure as described above, the range of Ra, etc., the presence or absence of the second microstructure, etc.) so that the antibacterial activity of the antibacterial metal material is more appropriately exhibited. For example, to inactivate small viruses, an antibacterial metal material with a somewhat thick second microstructure may be more effective.

[0097] Method for manufacturing antimicrobial metal materials

[0098] Antimicrobial metal materials can be manufactured by performing a roughening treatment on the surface of a metal material. The roughening treatment method is not particularly limited as long as it is a method that can make the roughness index of the antimicrobial metal material 4.0 or higher.

[0099] For example, a method using a laser as disclosed in Japanese Patent No. 4020957; a method of immersing the surface of a metal material in an aqueous solution of an inorganic base such as NaOH, or an inorganic acid such as HCl or HNO3; a method of treating the surface of a metal material by anodic oxidation as disclosed in Japanese Patent No. 4541153; a substitutional etching method as disclosed in International Publication No. 2015-8847, which etches using an aqueous solution of an acid-based etchant comprising an acid-based etchant (preferably an inorganic acid, ferric ions, or copper ions) and, if necessary, manganese ions, aluminum chloride hexahydrate, sodium chloride, etc. (hereinafter referred to as "harmonization treatment method 1"); Examples of methods for chemical treatment include: a method of immersing the surface of a metal material in one or more aqueous solutions selected from hydrated hydrazine, ammonia, and water-soluble amine compounds as disclosed in International Publication No. 2009 / 31632 (hereinafter referred to as “Treating Treatment Method 2”); a method of chemically treating the surface of a metal material by contacting it with an oxidizing acidic aqueous solution containing a predetermined metal cation as disclosed in International Publication No. 2020 / 158820 (hereinafter referred to as “Treating Treatment Method 3”); a hot water treatment method as disclosed in Japanese Patent Publication No. 2008-162115, Japanese Patent Publication No. 2019-018547, etc.; and treating treatments such as blast treatment. The treating treatment method can be classified and used according to the material of the metal material, the desired roughness index, the desired average hole diameter, etc.

[0100] Among the above-mentioned harmonic treatment methods, harmonic treatment methods 1 to 3 may be suitably used from the perspective of making the surface roughness index of the metal material 4.0 or higher. In addition, a treatment combining two or more of these harmonic treatment methods (for example, a harmonic treatment method combining harmonic treatment method 1 and harmonic treatment method 3) may also be suitably used. These treatments will be described in detail below.

[0101] [Harmonic Processing 1]

[0102] As a method of harmonization treatment 1, for example, the following processes (1) to (4) can be carried out in this order.

[0103] (1) Pretreatment process

[0104] In process (1), a pretreatment is performed to remove a film consisting of oxides or hydroxides present on the surface of the metal material. As a pretreatment, mechanical polishing or chemical polishing is typically performed. If there is significant contamination such as machine oil on the surface of the metal material, treatment with an alkaline aqueous solution such as a sodium hydroxide solution or a potassium hydroxide solution, or degreasing may be performed.

[0105] (2) Treatment process using an alkaline aqueous solution containing zinc ions

[0106] In process (2), alkali hydroxide (MOH or M(OH)2) and zinc ions (Zn 2+ ) mass ratio ((MOH or M(OH)2) / Zn 2+ A metal material after pretreatment is immersed in an aqueous alkali solution containing zinc ions in a ratio of 1 to 100 to form a zinc-containing film on the surface. In addition, M in MOH and M(OH)2 is an alkali metal or an alkaline earth metal.

[0107] (3) Treatment process using acid-based etching agents

[0108] In process (3), after the execution of process (2), the metal material is treated with an acid-based etchant comprising at least one of ferric ions and copper ions and an acid. By executing process (3), the zinc-containing film on the surface of the metal material is eluted, along with, for example, Ra of 4 μm to 6 μm, Rz of 20 μm to 35 μm, and RS of 90 μm to 120 μm. m A porous structure (first microstructure) having at least one of can be formed.

[0109] (4) Post-processing process

[0110] In process (4), the metal material is cleaned after the execution of process (3). The method of cleaning the metal material is not particularly limited and typically consists of washing and drying operations. The method of cleaning the metal material may include ultrasonic cleaning operations to remove smudges.

[0111] [Harmonic Processing 2]

[0112] In the 2nd treatment method, pretreatment with hydrochloric acid, sodium hydroxide, nitric acid, etc. is performed, and the metal material is immersed in a weakly basic amine-based aqueous solution such as hydrated hydrazine, then washed with water and dried at, for example, 70°C or lower. The immersion temperature and immersion time may be appropriately adjusted according to the desired roughness index, desired average hole diameter, etc.

[0113] By doing so, for example, a first microstructure having a porous structure of several hundred nanometers and a second microstructure having a mesh-like structure with an average thickness of several tens of nanometers, further imparted on the first microstructure, can be formed on the surface of a metal material.

[0114] [Harmony Processing Method 3]

[0115] As harmonization treatment method 3, for example, a method of contacting a metal material with a specific oxidizing acidic aqueous solution can be cited. The specific oxidizing acidic aqueous solution is a standard electrode potential E at 25°C 0It contains metal cations greater than -0.2 and less than or equal to 0.8, preferably greater than 0 and less than or equal to 0.5.

[0116] The above oxidizing acidic aqueous solution is, above E 0 It is desirable not to include metal cations with a value of -0.2 or less.

[0117] Standard electrode potential E at 25℃ 0 As a metal cation with a value greater than -0.2 and less than or equal to 0.8, Pb 2+ , Sn 2+ , Ag + , Hg 2+ , Cu 2+ Examples include the like. Among these, regarding the scarcity of the metal and the safety and toxicity of the corresponding metal salt, Cu 2+ It is desirable.

[0118] Cu 2+ Examples of compounds that generate [this] include inorganic compounds such as copper hydroxide, cupric oxide, cupric chloride, cupric bromide, copper sulfate, copper nitrate, and copper gluconate. Among these, copper oxide is preferred in terms of safety, toxicity, and efficiency of forming a dendrite layer.

[0119] Examples of oxidizing acidic aqueous solutions include nitric acid, mixed acids, and percarboxylic acid aqueous solutions (e.g., peracetic acid, performic acid, etc.). Mixed acids are obtained by mixing any one of hydrochloric acid, hydrofluoric acid, and sulfuric acid with nitric acid. When nitric acid is used as the oxidizing acidic aqueous solution and cupric oxide is used as the metal cation-generating compound, the concentration of nitric acid constituting the aqueous solution is, for example, 10 mass% to 40 mass%, preferably 15 mass% to 38 mass%, more preferably 20 mass% to 35 mass%. The concentration of copper ions constituting the aqueous solution is, for example, 1 mass% to 15 mass%, preferably 2 mass% to 12 mass%, more preferably 2 mass% to 8 mass%.

[0120] The temperature at which the metal material is brought into contact with the oxidizing acidic aqueous solution is not particularly limited, but in order to complete the process at an economical speed while controlling the exothermic reaction, for example, room temperature to 60°C, preferably 30°C to 50°C. The processing time at this time is, for example, in the range of 1 minute to 15 minutes, preferably 2 minutes to 10 minutes.

[0121] In this way, a dendritic layer (second microstructure) with an average thickness of, for example, several nm to several hundred nm can be formed on the surface of a metal material by the harmonization treatment method 3.

[0122] A resinous upper layer as described above can also be formed using the hot water treatment method disclosed in Japanese Patent Publication No. 2019-018547.

[0123] [Combination of Harmonic Processing 1 and Harmonic Processing 3]

[0124] In the combination of Harmonizing Treatment Method 1 and Harmonizing Treatment Method 3, Harmonizing Treatment Method 3 may be further performed, for example, on a metal material that has undergone harmonizing treatment in Harmonizing Treatment Method 1. By doing so, for example, Ra of 4 μm to 6 μm, Rz of 20 μm to 35 μm, and RS of 90 μm to 120 μm m A porous structure (first microstructure) having at least one of the above and a dendritic layer (second microstructure) with an average thickness of several nm to several hundred nm can be further imparted to the surface of the metal material.

[0125] Antibacterial products

[0126] The antimicrobial article according to the present disclosure comprises the antimicrobial metal material according to the present disclosure.

[0127] Antimicrobial articles are not particularly limited and can be widely used for various purposes, such as medical and pharmaceutical related products (e.g., medical pads, surgical instruments, lids for medicine bottles, dental materials, etc.); housing related products (e.g., door knobs, handrails, etc.); food and cooking related products (e.g., tableware, cooking utensils, sinks, faucets, wiring trays); infrastructure related products (e.g., water treatment, piping used in factory facilities, etc.); automobile related products (e.g., door knobs, etc.); general merchandise related products (e.g., pencil cases, stationery, mechanical pencils, electronic calculators, etc.); IT related products (e.g., housings for personal computers, smartphones, etc.); and entertainment related products (e.g., medals used in organic devices, etc.).

[0128] The method of manufacturing an antimicrobial article is not particularly limited, and an antimicrobial article may be manufactured by a conventional method using the antimicrobial metal material according to the present disclosure.

[0129] Examples

[0130] The present disclosure will be explained in more detail below with reference to examples. However, the present disclosure is not limited to these examples.

[0131] <Example 1>

[0132] The metal material used for the production of the antimicrobial metal material for the antimicrobial test and the metal material used for the production of the antimicrobial metal material for the virus inactivation test were prepared as follows.

[0133] (Antibacterial test)

[0134] An aluminum alloy (thickness: 0.2 cm) of alloy number A5052 specified in JIS H 4000: 2014 was cut into a length of 4.5 cm and a width of 2.0 cm to produce a metal material. The geometric surface area of ​​this metal material (sample) was 20.6 cm², the density was 2.68 g / cm³, the volume was 1.8 cm³, and the mass was 4.8 g.

[0135] (Virus Inactivation Test)

[0136] An aluminum alloy (thickness: 0.2 cm) of alloy number A5052 specified in JIS H 4000: 2014 was cut into a length of 3.5 cm and a width of 2.4 cm to produce a metal material. The geometric surface area of ​​this metal material (sample) was 19.2 cm², the density was 2.68 g / cm³, the volume was 1.7 cm³, and the mass was 4.5 g.

[0137] (Degreasing treatment)

[0138] Degreasing was performed on the metal material under the following conditions.

[0139] · Composition: Meltex Co., Ltd. Aluminum Cleaner "NE-6" 5 mass%, Water 95 mass%

[0140] · Temperature: 60℃

[0141] · Immersion time: 5 minutes

[0142] (Harmony processing)

[0143] A metal material after degreasing treatment was immersed in an aqueous hydrochloric acid solution, an aqueous sodium hydroxide solution, and an aqueous nitric acid solution, respectively, under the following conditions, and then washed with water to obtain a first microstructure.

[0144] Hydrochloric acid solution

[0145] · Composition: 1 mass% hydrochloric acid, 99 mass% water

[0146] · Temperature: 40℃

[0147] · Immersion time: 1 minute

[0148] Sodium hydroxide solution

[0149] · Composition: Sodium hydroxide 1.5 mass%, water 98.5 mass%

[0150] · Temperature: 40℃

[0151] · Immersion time: 4 minutes

[0152] Aqueous nitric acid solution

[0153] · Composition: Nitric acid 3 mass%, water 97 mass%

[0154] · Temperature: 40℃

[0155] · Immersion time: 3 minutes

[0156] Next, under the following conditions, the metal material having the first microstructure formed thereon was immersed in aqueous solution A containing hydrated hydrazine and aqueous solution B containing hydrated hydrazine, respectively, and then washed with water and dried at 70°C or lower to produce the antimicrobial metal material 1 of Example 1. In addition, the antimicrobial metal material for the antimicrobial test and the antimicrobial metal material for the virus inactivation test are not distinguished and are referred to as antimicrobial metal material 1.

[0157] <Aqueous solution A containing hydrated hydrazine>

[0158] · Composition: Hydrated hydrazine 3.5 mass%, water 96.5 mass%

[0159] · Temperature: 60℃

[0160] · Immersion time: 1 minute

[0161] <Aqueous solution B containing hydrated hydrazine>

[0162] · Composition: Hydrated hydrazine 0.5 mass%, water 99.5 mass%

[0163] · Temperature: 40℃

[0164] · Immersion time: 5 minutes

[0165] (Structural observation)

[0166] Using a scanning electron microscope “Regulus 8220” manufactured by Hitachi High Technologies, Inc., the surface and cross-section perpendicular to the surface of antimicrobial metal material 1 were observed. Antimicrobial metal material 1 had a porous structure (first microstructure) and a fine uneven structure layer (second microstructure), and did not have a specific structure.

[0167] (Roughness Index)

[0168] After vacuum heating and degassing (100°C) the antimicrobial metal material 1, the adsorption isotherm was measured using the krypton adsorption method at liquid nitrogen temperature (77K) with BELSORP-max (Microtrack Bel Co., Ltd.), and the specific surface area was calculated by the BET method. The true surface area (m²) of the antimicrobial metal material 1 was calculated by multiplying the specific surface area by the mass of the antimicrobial metal material. The roughness index of the antimicrobial metal material 1 was calculated by dividing the true surface area (m²) by the geometric surface area (m²).

[0169] In addition, since the change in geometric area and mass before and after the roughness treatment is very small and the effect on the calculated value of the roughness index is negligible, the geometric surface area and mass of the antimicrobial metal material 1 were used as those of the metal material.

[0170] (Arithmetic mean roughness, 10-point average roughness, average length of roughness curve elements)

[0171] Macroscopic surface characteristics (i.e., the average value of the arithmetic mean roughness (Ra) of the first microstructure, the average value of the 10-point average roughness (Rz), and the average value of the average length of the roughness curve elements (RS) m )) was measured in accordance with JIS B 0601:2001 using the surface roughness measuring device “SurfCom 1400D” manufactured by Tokyo Seimitsu Co., Ltd.

[0172] (Average thickness of the second microstructure)

[0173] The average thickness of the second microstructure was calculated from a cross-sectional profile obtained using a scanning electron microscope (SEM). Specifically, using a scanning electron microscope “Regulus 8220” manufactured by Hitachi High Technologies, SEM images were taken for 10 randomly selected points on an antimicrobial metal material, and for each image, the average thickness at a length of 1 μm was measured for any two spots, and similar measurements were performed for the other 9 points. Then, the average value of the total 20 measurements was defined as the average thickness of the second microstructure.

[0174] <Example 2>

[0175] Except for changing the harmonization treatment method as follows, the antimicrobial metal material 2 of Example 2 was prepared in the same manner as in Example 1, and structural observation was performed. The antimicrobial metal material 2 had a dendritic layer (second microstructure) and did not have a porous structure (first microstructure) or a specific structure. For the antimicrobial metal material 2, the roughness index, macroscopic surface characteristics (i.e., arithmetic mean roughness, 10-point average roughness, and average length of roughness curve elements), and the average thickness of the second microstructure (dendritic layer) were determined in the same manner as in Example 1. Furthermore, the antimicrobial metal material for the antimicrobial test and the antimicrobial metal material for the virus inactivation test are not distinguished and are referred to as antimicrobial metal material 2.

[0176] (Harmony processing)

[0177] Under the following conditions, the metal material is Cu 2+ The antimicrobial metal material 2 of Example 2 was prepared by contacting it with an oxidizing acidic aqueous solution containing and washing it with water.

[0178] <Cu 2+ Oxidizing acidic aqueous solution containing

[0179] · Composition: Copper sulfate 5.03 mass%, nitric acid 30 mass%, water 64.97 mass%

[0180] · Temperature: 40℃

[0181] · Immersion time: 5 minutes

[0182] <Example 3>

[0183] Except for changing the harmonization treatment method as described below, the antimicrobial metal material 3 of Example 3 was fabricated in the same manner as in Example 1, and structural observation was performed. The antimicrobial metal material 3 had a porous structure (first microstructure), a dendritic layer (second microstructure), and a specific structure. For the antimicrobial metal material 3, the roughness index, macroscopic surface characteristics (i.e., the average value of the arithmetic mean roughness, the average value of the 10-point average roughness, and the average length of the roughness curve elements), and the average thickness of the second microstructure (dendritic layer) were determined in the same manner as in Example 1. Furthermore, the antimicrobial metal material for the antimicrobial test and the antimicrobial metal material for the virus inactivation test are not distinguished and are referred to as antimicrobial metal material 3. In the specific structure of the antimicrobial metal material 3, the diameter of the opening was approximately 10 μm, and the maximum inner diameter of the hole was approximately 15 μm.

[0184] (Harmony processing)

[0185] As in Example 1, the degreased metal material was treated with alkali hydroxide (MOH) and zinc ions (Zn 2+ ) mass ratio (MOH / Zn 2+ A metal material after degreasing was immersed in an alkaline aqueous solution containing zinc ions in a ratio of 1 to 100 to form a zinc-containing film on the surface.

[0186] Next, under the following conditions, the metal material was treated with an acid-based etchant containing at least one of ferric ions and copper ions and an acid to elute the zinc-containing film on the surface of the metal material and washed with water.

[0187] Subsequently, under the following conditions, the metal material Cu 2+The antimicrobial metal material 3 of Example 3 was prepared by contacting it with an oxidizing acidic aqueous solution containing and washing it with water.

[0188] Alkaline aqueous solution containing zinc ions

[0189] · Composition: Sodium hydroxide 19 mass%, zinc oxide 3.2 mass%, water 77.8 mass%

[0190] · Temperature: 30℃

[0191] · Immersion time: 2 minutes

[0192] Acid Etching Agent

[0193] · Composition: Sulfuric acid 4.1 mass%, Ferric chloride 3.9 mass%, Cupric chloride 0.2 mass%, Water 91.8 mass%

[0194] · Temperature: 30℃

[0195] · Immersion time: 250 seconds

[0196] <Cu 2+ Oxidizing acidic aqueous solution containing

[0197] · Composition: Nitric acid 30 mass%, cupric oxide 6.3 mass%, water 63.7 mass%

[0198] · Temperature: 40℃

[0199] · Immersion time: 5 minutes

[0200] <Example 4>

[0201] Cu 2+The antimicrobial metal material 4 of Example 4 was prepared in the same manner as in Example 3, except that the oxidizing acidic aqueous solution containing [the substance] was changed to an aqueous solution containing copper sulfate under the following conditions, and structural observation was performed. The antimicrobial metal material 4 had a porous structure (first microstructure), a dendritic layer (second microstructure), and a specific structure. For the antimicrobial metal material 4, the roughness index, macroscopic surface characteristics (i.e., arithmetic mean roughness, 10-point average roughness, average length of roughness curve elements), and the average thickness of the second microstructure (dendritic layer) were determined in the same manner as in Example 1. Furthermore, the antimicrobial metal material for the antimicrobial test and the antimicrobial metal material for the virus inactivation test are referred to as antimicrobial metal material 4 without distinction. In the specific structure of the antimicrobial metal material 4, the diameter of the opening was approximately 10 μm, and the maximum inner diameter of the hole was approximately 15 μm.

[0202] Aqueous solution containing copper sulfate

[0203] · Composition: Nitric acid 30 mass%, copper sulfate 5.03 mass%, water 64.97 mass%

[0204] · Temperature: 40℃

[0205] · Immersion time: 5 minutes

[0206] <Example 5>

[0207] An aluminum plate used as a substrate was degreased in the same manner as in Example 1, and an underlayer nickel plating layer with a thickness of about 3 μm to 4 μm was formed on its surface.

[0208] The underlayer nickel plating layer is prepared by using an aqueous solution containing nickel sulfate (280 g / L), nickel chloride (45 g / L), and boric acid (40 g / L) as the plating solution, at a solution temperature of 50°C, pH 4.3, and a cathodic current density of 3 A / dm² 2 It was carried out under the conditions of.

[0209] Next, a nickel plating layer having a porous structure with a thickness of about 1 μm to 5 μm was formed on the base nickel plating layer.

[0210] A nickel plating layer having a porous structure is formed using a plating solution in which dodecyltrimethylammonium chloride (10 ml / L) is added as a substance inhibiting the growth of the plating layer to an aqueous solution containing nickel sulfate (280 g / L), nickel chloride (45 g / L), and boric acid (40 g / L), at a liquid temperature of 50°C, pH 4.3, and a cathodic current density of 3 A / dm² 2 It was carried out under the conditions of.

[0211] For an aluminum plate having a nickel plating layer with a porous structure, an etching treatment was performed by immersing it in an aqueous solution (40°C) containing 0.6 mass% nitric acid and 7.5 mass% phosphoric acid for 3 minutes.

[0212] Accordingly, the antimicrobial metal material 5 of Example 5 was fabricated, and structural observation was performed. The antimicrobial metal material 5 had a porous structure (first microstructure), a needle-like layer (second microstructure), and a specific structure. For the antimicrobial metal material 5, the roughness index, macroscopic surface characteristics (i.e., arithmetic mean roughness, 10-point average roughness, average length of roughness curve elements), and the average thickness of the second microstructure (needle-like layer) were determined in the same manner as in Example 1. Furthermore, the antimicrobial metal material for the antimicrobial test and the antimicrobial metal material for the virus inactivation test are not distinguished and are referred to as antimicrobial metal material 5. In the specific structure of the antimicrobial metal material 5, the diameter of the opening and the maximum inner diameter of the hole were both approximately 2 μm, and a location was identified where the diameter of the opening was smaller than the maximum inner diameter of the hole.

[0213] <Comparative Example 1>

[0214] The metal material used in Example 1 before the tamping treatment was degreased in the same manner as in Example 1 and used as Comparative Example 1, and the roughness index and macroscopic surface properties (i.e., arithmetic mean roughness, 10-point average roughness, and average length of roughness curve elements) were determined in the same manner as in Example 1. In addition, the structure of the antibacterial metal material of Comparative Example 1 was observed in the same manner as in Example 1, and neither the first microstructure nor the second microstructure was observed.

[0215] Antibacterial Test

[0216] Antimicrobial testing was performed in accordance with ISO 21702: 2019 using antimicrobial metal materials that had been sterilized with ethanol.

[0217] The test bacterium was one species of Staphylococcus aureus, and the inoculation concentration was 2.5 × 10⁻⁶ 5 Pieces / mL to 10 6 The test bacterial culture volume is 1 / 25 NB, and the volume is 1 / mL.

[0218] In the antibacterial test, the ratio of viable bacteria was measured 30 minutes and 24 hours after inoculating the antibacterial metal material with the test bacterial solution.

[0219] The viable cell count ratio (%) after 30 minutes refers to the ratio of the number of viable cells 30 minutes after inoculation of the antimicrobial metal material to the number of viable cells at the time of inoculation of the test bacterial solution. The viable cell count ratio (%) after 24 hours refers to the ratio of the number of viable cells 24 hours after inoculation of the antimicrobial metal material to the number of viable cells at the time of inoculation of the test bacterial solution. The lower the viable cell count ratio (%), the more bacteria are damaged.

[0220] Antibacterial testing was performed on the antibacterial metal materials of Examples 1, 2, 4, and 5, and the antibacterial metal material of Comparative Example 1, in accordance with the above method. The results are shown in Table 1.

[0221] Virus Inactivation Test

[0222] In accordance with ISO 21702: 2019, a virus inactivation test was performed using an antimicrobial metal material. In the virus inactivation test, the virus inactivation rate and infection value were measured 30 minutes and 24 hours after inoculating the antimicrobial metal material with the test virus solution. The infection value is an indicator representing the degree of virus inactivation. Two types of viruses were used: Influenza A H3N2 (size: 80 nm to 120 nm, with envelope) and feline calicivirus (size: 27 nm to 32 nm, without envelope).

[0223] For the antimicrobial metal materials of Examples 1, 3, 4, and 5, and the metal material of Comparative Example 1, a virus inactivation test was performed according to the above procedure. In addition, for the antimicrobial metal material 1 of Example 1, the virus inactivation rate and infection value after 24 hours against Influenza A H3N2 were not evaluated. The results are shown in Table 2.

[0224] The virus inactivation rate after 30 minutes represents the ratio of the infection rate 30 minutes after the test virus solution was inoculated into antimicrobial metal material 1 to the infection rate at the time the test virus solution was inoculated into antimicrobial metal material 1. The virus inactivation rate after 24 hours represents the ratio of the infection rate 24 hours after the test virus solution was inoculated into antimicrobial metal material 1 to the infection rate at the time the test virus solution was inoculated into antimicrobial metal material 1. A higher virus inactivation rate indicates that the activity of more viruses is weakened.

[0225] Viral infection was measured by TCID50 (50% tissue culture infectious dose).

[0226]

[0227]

[0228] The roughness index of Comparative Example 1 was less than 4.0. Therefore, the viable cell count ratio of the antimicrobial metal material of Comparative Example 1 after 24 hours was 17%. The virus inactivation rate against feline calicivirus of the antimicrobial metal material of Comparative Example 1 after 24 hours was 99.991%.

[0229] Meanwhile, the roughness index of Examples 1 to 5 was 4.0 or higher. Therefore, the viable cell count ratio of the antimicrobial metal materials of Examples 1, 2, 4, and 5 after 24 hours was 0.202% or lower, which was lower than that of Comparative Example 1. In other words, it was found that the antimicrobial metal materials of Examples 1, 2, 4, and 5 possess antimicrobial performance.

[0230] The virus inactivation rate of the antimicrobial metal materials of Examples 1, 3 to 5 against feline calicivirus after 24 hours was 99.999% or higher, which was higher than that of Comparative Example 1. That is, it was found that the antimicrobial metal materials of Examples 1, 3 to 5 possess virus inactivation performance.

[0231] From these results, it was found that Examples 1 to 5 possess at least one of antibacterial performance and virus inactivation performance. In other words, it was found that the antibacterial properties of the antibacterial metal materials of Examples 1 to 5 are excellent.

[0232] As shown in Table 1, the antimicrobial metal materials of Examples 1, 2, and 4 had a low viable cell count ratio and exhibited excellent antimicrobial properties. In particular, 24 hours after inoculation of the test bacterial solution, the viable cell count ratio could be significantly reduced to 0.202% or less. On the other hand, the metal material of Comparative Example 1 had a high viable cell count ratio and exhibited poor antimicrobial properties.

[0233] As shown in Table 2, the antimicrobial metal materials of Examples 1, 3, and 4 exhibited excellent antimicrobial properties, with a high virus inactivation rate and a low infection value. In particular, 24 hours after inoculation with the test virus solution, the virus inactivation rate for feline calicivirus could be significantly increased to 99.999% or higher, and the infection value could be significantly reduced to 2.28 LogTCID50 / mL or lower. On the other hand, the metal material of Comparative Example 1 showed poor antimicrobial properties, with a low virus inactivation rate for Influenza A H3N2 after 30 minutes.

[0234] In addition, among the antimicrobial metal materials of Examples 1, 3, and 4 having a first microstructure and a second microstructure layer, Ra, Rz, and RS m The antimicrobial metal materials of Examples 3 and 4, which have a larger and thicker second microstructure, exhibited superior antimicrobial properties compared to the antimicrobial metal material 1 of Example 1, showing a high inactivation rate even 30 minutes after inoculation with the test virus solution. For Influenza A H3N2, the virus inactivation rate could be significantly increased to 99.997% or higher after 24 hours from inoculation with the test virus solution, and the infection value could be significantly reduced to 2.28 LogTCID50 / mL or lower.

[0235] The disclosure of Japanese patent application 2021-129074 filed on August 5, 2021, is incorporated herein by reference in its entirety.

[0236] All documents, patent applications, and technical specifications described in this specification are introduced by reference within this specification to the same extent that individual documents, patent applications, and technical specifications are introduced by reference as they are specifically and individually described.

Claims

Claim 1 An antibacterial metal material having a surface with a roughness index of 4.0 or higher, obtained by dividing the true surface area (m²) measured by the krypton adsorption method by the geometric surface area (m²), wherein the surface has an uneven structural layer with an average thickness of 150 nm to 1000 nm, and the surface satisfies the following (1) to (3): (1) an average value of arithmetic mean roughness (Ra) of 0.2 μm to 20 μm, (2) an average value of 10-point average roughness (Rz) of 2 μm to 100 μm, (3) an average length of roughness curve elements (RS m The average value of ) is 10㎛ to 400㎛. Claim 2 In claim 1, the antibacterial metal material having a porous surface structure. Claim 3 In paragraph 2, an antibacterial metal material having a plating layer, wherein the surface is the surface of the plating layer. Claim 4 An antibacterial metal material according to claim 2 or 3, wherein the diameter of at least some of the openings of a plurality of holes is smaller than the maximum inner diameter of the holes. Claim 5 In any one of claims 1 to 3, the average value of the arithmetic mean roughness (Ra) is 3 μm or more, the average value of the 10-point average roughness (Rz) is 20 μm or more, and the average length of the roughness curve element (RS m Antimicrobial metal material having an average value of ) of 100㎛ or more. Claim 6 An antibacterial metal material according to any one of claims 1 to 3, wherein the uneven structural layer is a dendritic layer or a mesh layer. Claim 7 An antibacterial metal material according to any one of claims 1 to 3, wherein the average thickness is greater than 200 nm. Claim 8 An antibacterial metal material according to any one of claims 1 to 3, wherein the average thickness is 350 nm or more. Claim 9 An antimicrobial metal material according to any one of claims 1 to 3, comprising at least one selected from the group consisting of aluminum, magnesium, silver, copper, iron, titanium, alloys, and plating materials, wherein the alloy comprises at least one selected from the group consisting of aluminum, magnesium, silver, copper, iron, and titanium. Claim 10 An antibacterial metal material according to any one of claims 1 to 3, wherein the roughness index is 95.0 or higher. Claim 11 An antimicrobial article comprising an antimicrobial metal material described in any one of paragraphs 1 to 3. Claim 12 delete Claim 13 delete

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