Antiviral composition, coating material, filter, antiviral member, and method for producing the compound

Abstract

To provide a compound having both antiviral and photocatalytic properties, an antiviral composition, a coating material, a filter, an antiviral member, and a method for producing the compounds.SOLUTION: A compound according to the present disclosure is a compound in which some of the sodium ions of sodium trititanate are substituted with silver ions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to compounds, antiviral compositions, coating materials, filters, antiviral components, and methods for producing the compounds. [Background technology]

[0002] Titanium oxide is known as a photocatalytic material, which generates a strong oxidizing effect on the surface of the material in response to ultraviolet or visible light, and thus can exhibit certain antibacterial and antiviral properties (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-101155 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in recent years, as awareness of the dangers of viral infections has increased, there is a demand for materials with even better antiviral properties.

[0005] An object of the present invention is to provide a compound having both antiviral and photocatalytic properties, an antiviral composition, a coating material, a filter, an antiviral member, and a method for producing the compound. [Means for solving the problem]

[0006] The present inventors conceived the idea that introducing silver ions, which have antiviral properties, into titanium oxide, which has photocatalytic properties, could impart antiviral properties to titanium oxide. As a result of extensive research, the present inventors discovered that a compound possessing both antiviral and photocatalytic properties can be obtained by substituting silver ions for the sodium ions located between the layers of sodium trititanate, which has a layered crystal structure.

[0007] The present invention includes the following aspects. [1] A compound in which some of the sodium ions in sodium trititanate are replaced with silver ions. [2] The compound according to [1], in which more than 0 atomic percent and not more than 50 atomic percent of all sodium ions are substituted with silver ions. [3] The compound according to [2], in which 15 atomic percent to 35 atomic percent of all sodium ions are substituted with silver ions. [4] An antiviral composition comprising the compound according to any one of [1] to [3]. [5] A coating material comprising the compound according to any one of [1] to [3] and a binder. [6] The coating material according to [5], wherein the compound is contained in the form of particles, and the median diameter of the particles is 0.1 μm or more and 100 μm or less. [7] The coating material according to [5] or [6], wherein the mass ratio of the content of the compound in the coating material to the content of the solid content of the binder is 0.01 or more and 1 or less. [8] A filter comprising the compound according to any one of [1] to [3]. [9] An antiviral member comprising a substrate and a coating layer formed on the surface of the substrate, the coating layer containing the compound according to any one of [1] to [3].

[10] An antiviral member comprising a substrate and particles of the compound according to any one of [1] to [3] dispersed within the substrate.

[11] A method for producing a compound in which some of the sodium ions in sodium trititanate are substituted with silver ions, comprising: A method comprising mixing sodium trititanate with a solution containing silver ions.

[12] The method according to

[11] , wherein the solution is an aqueous solution of one or more silver salts selected from the group consisting of silver nitrate, silver nitrite, silver sulfate, and silver acetate.

[13] The method according to

[11] or

[12] , wherein the sodium trititanate is mixed with the solution in the form of particles, and the sodium trititanate particles have a median diameter of 0.1 μm or more and 500 μm or less. [Effects of the Invention]

[0008] According to embodiments of the present invention, it is possible to provide a compound having both antiviral and photocatalytic properties, an antiviral composition, a coating material, a filter, an antiviral member, and a method for producing the compound. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an antiviral member according to a first embodiment. [Figure 2] FIG. 10 is a cross-sectional view of an antiviral member according to a second embodiment. [Figure 3] 1 shows the X-ray diffraction (XRD) pattern measured in Example 1-1. [Figure 4] 1 shows a scanning electron microscope (SEM) photograph of the sodium trititanate fine powder taken in Example 1-1. [Figure 5] 1 shows the particle size distribution of the sodium trititanate fine powder measured in Example 1-1. [Figure 6] 1 shows an SEM photograph of the silver-substituted sodium trititanate fine powder taken in Example 1-1. [Figure 7] 1 shows the particle size distribution of the silver-substituted sodium trititanate fine powder measured in Example 1-1. [Figure 8] This shows the change over time in absorbance of methylene blue adsorbed on a sample in an experiment to evaluate photocatalytic properties. DETAILED DESCRIPTION OF THE INVENTION

[0010] The compounds, antiviral compositions, coating materials, filters, antiviral members, and methods for producing the compounds according to the embodiments are described below. Note that the following embodiments illustrate one aspect of the present invention, do not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention.

[0011] <Compound> According to one embodiment of the present invention, there is provided a compound in which some of the sodium ions in sodium trititanate are substituted with silver ions, hereinafter referred to as "silver-substituted sodium trititanate."

[0012] (Silver-substituted sodium trititanate) Silver-substituted sodium trititanate has a layered crystal structure in which some of the sodium ions located between the layers of sodium trititanate have been substituted with silver ions. That is, silver-substituted sodium trititanate has a crystal structure in which some of the sodium ions located between the layers have been removed and replaced by silver ions.

[0013] In silver-substituted sodium trititanate, for example, more than 0 atomic percent to 90 atomic percent of the total sodium ions are substituted with silver ions. Preferably, 1 atomic percent to 50 atomic percent, 5 atomic percent to 45 atomic percent, 10 atomic percent to 40 atomic percent, 15 atomic percent to 35 atomic percent, or 20 atomic percent to 30 atomic percent of the total sodium ions are substituted with silver ions. For example, 5 atomic percent to 35 atomic percent of the total sodium ions are substituted with silver ions. The upper and lower limits of these numerical ranges can be combined arbitrarily.

[0014] Silver-substituted sodium trititanate has the chemical formula (Na 1-x Ag x) It is a compound represented by 2Ti3O7(0 < x < 1). For example, 0 < x ≤ 0.9, preferably 0.01 ≤ x ≤ 0.5, more preferably 0.05 ≤ x ≤ 0.45, more preferably 0.1 ≤ x ≤ 0.4, more preferably 0.15 ≤ x ≤ 0.35, and more preferably 0.2 ≤ x ≤ 0.3. For example, 0.05 ≤ x ≤ 0.35. The upper and lower limit values of these numerical ranges can be arbitrarily combined.

[0015] (Antiviral property) The inventor of the present invention has found that silver-substituted sodium titanate has antiviral properties. In this specification, "antiviral property" means the property of suppressing the growth of viruses (excluding those due to the photocatalytic effect). Silver-substituted sodium titanate suppresses the growth of viruses by inactivating the viruses.

[0016] (Method for evaluating antiviral property) The antiviral property can be evaluated based on the antiviral activity value Mv conforming to Annex G of ISO 18184. The antiviral activity value Mv is calculated from the virus infection titer measured by the plaque measurement method. According to Annex G of ISO 18184, when 2.0 ≤ Mv < 3.0, the measurement sample is evaluated to have an antiviral effect, and when 3.0 ≤ Mv, the measurement sample is evaluated to have a sufficient antiviral effect. On the other hand, when Mv < 2.0, it is evaluated that no significant antiviral effect is observed.

[0017] The antiviral activity value Mv of the coating material containing 20% by mass of silver-substituted sodium titanate conforming to Annex G of ISO 18184 is 2.0 or more, preferably 3.0 or more.

[0018] (Photocatalytic properties) The inventors further focused on the photocatalytic properties of titanium oxide. As described below, the inventors confirmed that sodium trititanate retains photocatalytic properties even after silver substitution. In this specification, "photocatalytic properties" refers to the property of oxidizing the surface of a material when irradiated with ultraviolet or visible light. Therefore, silver-substituted sodium trititanate possesses antibacterial and antiviral properties due to its photocatalytic properties in addition to the antiviral properties of silver ions. As a result, silver-substituted sodium trititanate can strongly inhibit viral proliferation.

[0019] The median diameter of silver-substituted sodium trititanate particles is 0.1 μm or more and 500 μm or less. In this specification, "median diameter" refers to the median value of the particle size distribution measured on a particle volume basis. The particle size distribution is measured, for example, using a laser diffraction particle size distribution analyzer. If the median diameter of the particles is smaller than 0.1 μm, when silver-substituted sodium trititanate particles are mixed with a binder or the like to form a composition, the particles may be buried in the binder. In this case, the particles may not be able to sufficiently contact the virus, and sufficient antiviral effect may not be obtained. On the other hand, if the median diameter of the particles is larger than 500 μm, the specific surface area will be smaller than when the median diameter is smaller. In this case, sufficient antiviral effect may not be obtained relative to the amount of particles.

[0020] The median diameter of the silver-substituted sodium trititanate particles is, for example, 1.0 μm or more, 5.0 μm or more, 7.0 μm or more, or 9.0 μm or more. The median diameter of the silver-substituted sodium trititanate particles is, for example, 100 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less. The upper and lower limits of these numerical ranges can be combined in any combination.

[0021] The median diameter of the silver-substituted sodium trititanate particles is larger than that of the sodium trititanate particles before silver substitution, which, without being bound by theory, is thought to be due in part to aggregation of the particles after silver substitution.

[0022] <Method of manufacturing the compound> According to one embodiment of the present invention, there is provided a method for producing a compound in which some of the sodium ions in sodium trititanate have been substituted with silver ions, the method comprising mixing sodium trititanate powder with a solution containing silver ions (mixing step).

[0023] The production method may include a milling step of milling sodium trititanate powder before or after the mixing step. The production method may include a parameter determination step of determining various parameters for achieving a target value of the silver ion substitution amount before the mixing step. The production method may also include an isolation step of isolating the reaction product from the reaction solution after the mixing step.

[0024] (sodium trititanate) The sodium trititanate Na2Ti3O7 used in the above manufacturing method has a layered crystal structure with TiO6 as a constituent unit, and has a crystal structure in which sodium ions are located between the layers.

[0025] The sodium trititanate used as a raw material is mixed with the above solution in the form of particles. The sodium trititanate particles have a median diameter of 0.1 μm or more and 500 μm or less. If the median diameter of the particles is smaller than 0.1 μm, it may be difficult to refine the particles. On the other hand, if the median diameter of the particles is larger than 500 μm, the silver ion replacement may not reach the inside of the particles, and sufficient replacement may not be achieved.

[0026] The median diameter of the sodium trititanate particles is, for example, 1.0 μm or more, 3.0 μm or more, 5.0 μm or more, or 7.0 μm or more. The median diameter of the sodium trititanate particles is, for example, 100 μm or less, 50 μm or less, 20 μm or less, 10 μm or less, or 8 μm or less. The upper and lower limits of these numerical ranges can be combined in any way.

[0027] (solution containing silver ions) The solution containing silver ions is a solution of any silver salt. The silver ions are, for example, monovalent silver ions, Ag + The silver salt is not particularly limited as long as it dissolves in the solvent used. When the solvent is water, the silver salt may be water-soluble. For example, the silver salt may be one or more selected from the group consisting of silver nitrate, silver nitrite, silver sulfate, and silver acetate.

[0028] (Crushing step) In the pulverization step, the sodium trititanate powder is pulverized to a size suitable for the ion exchange reaction (for example, until the median diameter falls within the above range). The pulverization method is not particularly limited, and any known method can be used, such as a ball mill, a bead mill, a planetary mill, mortar pulverization, or airflow pulverization. The conditions of the pulverization step, such as the temperature and time, are not particularly limited. The pulverization step may include, after the pulverization step, a washing step for washing the pulverized sodium trititanate powder and a drying step for drying the powder.

[0029] (Parameter determination step) In the parameter determination step, the target amount of silver ion substitution is determined, and experimental parameters suitable for achieving the determined amount of substitution are determined. Examples of experimental parameters include the blending amount of sodium trititanate powder and the silver ion-containing solution, the silver ion concentration of the solution, the particle size of the sodium trititanate used, the type of silver salt used, the temperature of the mixing step, and the time of the mixing step. When other additives are used, the amounts of these additives added are also included in the experimental parameters. In particular, appropriately adjusting the blending amount of sodium trititanate powder and the silver ion-containing solution (i.e., the solid-liquid ratio) and the silver ion concentration of the solution is preferred because it allows for easy control of the amount of silver ion substitution.

[0030] (Mixing step) In the mixing step, sodium trititanate powder is mixed with a solution containing silver ions. The solution containing silver ions may be added to sodium trititanate powder, or sodium trititanate powder may be added to the solution containing silver ions. This causes ion exchange, and some of the sodium ions contained in the sodium trititanate are substituted with silver ions. As a result, silver-substituted sodium trititanate is obtained.

[0031] The temperature of the mixing step is not particularly limited as long as it is a temperature at which ion exchange occurs. For example, the mixing step may be performed at room temperature. The temperature of the mixing step is, for example, 10°C or higher or 20°C or higher, and 100°C or lower, 90°C or lower, 50°C or lower, 40°C or lower, or 30°C or lower. The upper and lower limits of these numerical ranges can be combined arbitrarily.

[0032] The duration of the mixing step is not particularly limited as long as it is long enough for ion exchange to occur. For example, the mixing step may be carried out for 1 minute to 24 hours. The duration of the mixing step may be, for example, 5 minutes to 12 hours, 10 minutes to 6 hours, 30 minutes to 3 hours, or 1 hour to 2 hours. The upper and lower limits of these numerical ranges may be combined in any combination.

[0033] (Isolation step) In the isolation step, the produced silver-substituted sodium trititanate is isolated from the reaction solution. The isolation method is not particularly limited, and any known method such as filtration or chromatography can be used. After the above separation step, the isolation step may include a washing step for washing the isolated silver-substituted sodium trititanate powder and a drying step for drying the powder.

[0034] (Amount of silver ions adsorbed) The amount of silver ions adsorbed in silver-substituted sodium trititanate can be calculated from the amount of silver ions lost from a solution containing silver ions. Here, the "amount of adsorbed" of silver ions refers to the value obtained by dividing the number of moles of silver ions lost from a silver ion source (e.g., a solution containing silver ions, such as an aqueous silver nitrate solution) before and after the ion exchange operation in sodium trititanate by the mass of sodium trititanate introduced into the system. The number of moles of silver ions lost from the silver ion source can be calculated, for example, by quantifying the silver ion concentrations of the solution containing silver ions before and after the mixing step using any method and calculating the difference.

[0035] The adsorption amount of silver ions in silver-substituted sodium trititanate is, for example, more than 0 mmol / g to 6 mmol / g or less, and preferably 0.066 mmol / g to 3.3 mmol / g, 0.33 mmol / g to 3 mmol / g, 0.66 mmol / g to 2.7 mmol / g, 1 mmol / g to 2.3 mmol / g, 1.3 mmol / g to 2 mmol / g, or 1.5 mmol / g to 1.7 mmol / g. The upper and lower limits of these numerical ranges can be combined in any combination.

[0036] The amount of silver ions adsorbed is estimated to be the amount of silver ions adsorbed to sodium trititanate per unit mass (e.g., exchanged for sodium ions in the crystal structure). Therefore, the atomic percentage (x) of the amount of silver ions substituted in the above-mentioned silver-substituted sodium trititanate can be calculated from the amount of silver ions adsorbed in the silver-substituted sodium trititanate. Since the amount of silver ions adsorbed, A, is the number of moles of silver ions per unit mass of sodium trititanate (raw material), converting this to a value per mole of sodium ions contained in the raw material (approximately 6.631 mmol per unit mass of sodium trititanate) gives the atomic percentage (x) of the amount of silver ion substitution. That is, x = A / (6.631 mmol / g).

[0037] <How to use the compound> According to one embodiment of the present invention, there is provided a method for using a compound in which some of the sodium ions in sodium trititanate have been substituted with silver ions. For example, the method is a method for using the compound to reduce viruses. For example, the method includes contacting the compound with a virus. For example, an antiviral composition containing the compound can be used as a material for producing an antiviral device. For example, an antiviral device containing the compound can be used as a hygiene product for reducing viruses.

[0038] <Antiviral composition> According to one embodiment of the present invention, an antiviral composition is provided that includes silver-substituted sodium trititanate. The antiviral composition has antiviral properties against one or more types of viruses, such as enveloped and non-enveloped viruses. The antiviral composition can be used as a composition for reducing viruses. For example, the antiviral composition has both antiviral and photocatalytic properties.

[0039] The antiviral composition may contain optional components such as a binder, a solvent, a dispersion medium, a dispersant, an adhesive, and an additive, in addition to the silver-substituted sodium trititanate.

[0040] <Coating materials> According to one embodiment of the present invention, there is provided a coating material comprising silver-substituted sodium trititanate and a binder, for example, an antiviral composition that combines antiviral and photocatalytic properties.

[0041] The coating material contains silver-substituted sodium trititanate in the form of particles, with the median particle diameter being 0.1 μm or more and 100 μm or less. In this specification, if the median particle diameter is smaller than 0.1 μm, the particles may be embedded in the binder and not be exposed from the surface of the coating layer. In this case, sufficient antiviral effect may not be obtained. On the other hand, if the median particle diameter is larger than 100 μm, significant particle-induced irregularities may occur on the surface of the coating layer.

[0042] (binder) The binder can support the silver-substituted sodium trititanate particles. For example, a polymer material such as a resin can be used as the binder. Examples of the binder include polyethylene, polypropylene, acrylic, and ester amide resins.

[0043] The content of silver-substituted sodium trititanate in the coating material is 1 part by mass or more and 50 parts by mass or less, based on 100 parts by mass of the entire coating material. If the content of silver-substituted sodium trititanate is less than 1 part by mass, sufficient antiviral effect may not be obtained for the amount of coating material used. If the content of silver-substituted sodium trititanate is more than 50 parts by mass, the solid components in the coating material may become excessive, which may make coating difficult.

[0044] For example, the content of silver-substituted sodium trititanate is 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more, and 45 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less, based on 100 parts by mass of the total solid content of the coating material. The upper and lower limits of these numerical ranges can be combined in any way.

[0045] The mass ratio of the silver-substituted sodium trititanate content to the binder solids content in the coating material is 0.01 or more and 1 or less. If the mass ratio is less than 0.01, the silver-substituted sodium trititanate particles may not be sufficiently exposed from the binder. In this case, sufficient antiviral effect may not be achieved. If the mass ratio is greater than 1, the powder components in the coating material may not be sufficiently bound by the binder.

[0046] For example, the mass ratio of silver-substituted sodium trititanate to the solid content of the binder is 0.05 or more, 0.11 or more, 0.18 or more, or 0.25 or more, and 0.82 or less, 0.67 or less, 0.54 or less, or 0.43 or less. The upper and lower limits of these numerical ranges can be combined in any manner.

[0047] <Anti-virus materials> According to one embodiment of the present invention, there is provided an antiviral material comprising silver-substituted sodium trititanate. For example, the antiviral material is a material that exhibits antiviral and photocatalytic properties. Examples of the antiviral material include filters, films, fibers, and clothing.

[0048] FIG. 1 shows a cross-sectional view of an antiviral member 10 according to a first embodiment. As shown in FIG. 1, the antiviral member 10 has a substrate 100 and a coating layer 110 formed on the surface of the substrate 100. The coating layer 110 includes silver-substituted sodium trititanate particles 120 and a binder 130 in which the particles 120 are dispersed. The antiviral member 10 can be manufactured, for example, by applying a coating material, in which the silver-substituted sodium trititanate particles 120 are dispersed in the binder 130, to the surface of the substrate 100 as the coating layer 110. Furthermore, for example, when the substrate 100 is a member including an internal space, such as a fibrous member or a mesh-like member, the antiviral member 10 can be manufactured by immersing the substrate 100 in a dispersion of the silver-substituted sodium trititanate particles 120 or by impregnating the substrate 100 with the dispersion.

[0049] The substrate 100 is not particularly limited, and may be, for example, a nonwoven fabric, a woven fabric, paper, a cured resin, a metal plate, a metal mesh, or a glass plate. For example, the substrate 100 may be a plate-like or sheet-like member. For example, the substrate 100 may be a porous member having a plurality of small holes. The substrate 100 may be a hard member or a flexible member.

[0050] The coating layer 110 is formed, for example, in a sheet form on the surface of the substrate 100. When the substrate 100 has holes, the coating layer 110 may be formed three-dimensionally so as to cover the inner surfaces of the holes, or may be formed flat so as to cover the openings of the holes without covering the inner surfaces. An additional layer, such as an adhesive layer containing a binder, may be provided between the substrate 100 and the coating layer 110. Furthermore, an additional layer, such as a protective layer, may be provided on the surface of the coating layer 110.

[0051] FIG. 2 shows a cross-sectional view of an antiviral member 20 according to a second embodiment. As shown in FIG. 2, the antiviral member 20 includes a substrate 200 and silver-substituted sodium trititanate particles 220 dispersed within the substrate 200. The antiviral member 20 is produced, for example, by mixing a resin material serving as the raw material for the substrate 200 with the silver-substituted sodium trititanate particles 220 and forming the mixture into a sheet (for example, by extrusion molding as a nonwoven fabric). The substrate 200 is not particularly limited, and the same material as the substrate 100 can be used. For example, when the substrate 200 is a fibrous member such as a woven fabric or nonwoven fabric, the silver-substituted sodium trititanate particles 220 can be supported on the fibers.

[0052] An example of the antiviral member is a filter containing silver-substituted sodium trititanate. For example, the filter includes a filter substrate (e.g., a porous or fibrous filter substrate) having one or more holes formed therein and silver-substituted sodium trititanate particles supported on the filter substrate. Examples of filters include masks, air filters (e.g., intake filters and exhaust filters), mesh filters, and filter paper. By imparting antiviral properties to a filter, viruses contained in a fluid can be inactivated as the fluid passes through the filter. In particular, by preparing an existing filter as the substrate 100 of the first embodiment and forming a coating layer 110 on the substrate 100, antiviral properties can be easily imparted to the existing filter. In particular, imparting antiviral properties to a mask is advantageous for maintaining health and preventing disease. [Example]

[0053] [Example 1-1] 1.4 L of ultrapure water was added to 1.1 kg of sodium trititanate Na2Ti3O7 powder (T-62, manufactured by Fushimi Chemical Co., Ltd.), and the mixture was pulverized by ball milling at room temperature for 10 hours. The obtained pulverized product was washed and dried at 100 °C to obtain fine powder. By measuring the X-ray diffraction (XRD) pattern of the obtained fine powder, it was confirmed that the fine powder was sodium trititanate. The XRD patterns of the samples before and after pulverization are shown as (a) and (b) in Fig. 3, respectively. It was confirmed that the crystal structure of the sample did not change before and after pulverization.

[0054] The particles of the obtained sodium trititanate fine powder were observed with a scanning electron microscope (SEM). Fig. 4 is a SEM photograph of the sodium trititanate fine powder. Also, the particle size distribution of the obtained sodium trititanate fine powder was measured with a particle size distribution analyzer SALD-7100 (manufactured by Shimadzu Corporation). The measured particle size distribution is shown in Fig. 5. The median diameter of the particle size distribution was 7.199 μm, the mode diameter was 8.131 μm, the average value was 5.788 μm, and the standard deviation was 0.430 μm.

[0055] Next, 2 L of a 50 mmol / L silver nitrate AgNO3 aqueous solution was added to 20 g of the obtained sodium trititanate fine powder, and the mixture was stirred at room temperature for 2 hours to perform ion exchange of the sodium trititanate fine powder. Then, the reaction solution was filtered, washed, and dried to obtain ion-exchanged silver-substituted sodium trititanate (Na 1-x Ag x )2Ti3O7 (0 < x < 1) fine powder.

[0056] The XRD pattern of the obtained fine powder is shown in Fig. 3(c), the SEM photograph is shown in Fig. 6, and the particle size distribution is shown in Fig. 7, respectively. It was confirmed that the crystal structure of the sample did not change before and after ion exchange. The median diameter of the particle size distribution was 9.596 μm, the mode diameter was 9.992 μm, the average value was 6.111 μm, and the standard deviation was 0.648 μm. The adsorption amount of silver ions in silver-substituted sodium trititanate calculated from the remaining amount of silver ions in the silver nitrate aqueous solution after ion exchange was 1.692 mmol / g.

[0057] [Example 1-2] Ion-exchanged silver-substituted sodium trititanate fine powder was obtained in the same manner as in Example 1-1, except that the concentration of the silver nitrate aqueous solution was changed to 100 mmol / L. The amount of silver ions adsorbed by the silver-substituted sodium trititanate was 1.644 mmol / g.

[0058] [Examples 1-3] Ion-exchanged silver-substituted sodium trititanate fine powder was obtained in the same manner as in Example 1-1, except that the concentration of the silver nitrate aqueous solution was changed to 200 mmol / L. The amount of silver ions adsorbed by the silver-substituted sodium trititanate was 1.708 mmol / g.

[0059] [Examples 1-4] Ion-exchanged silver-substituted sodium trititanate fine powder was obtained in the same manner as in Example 1-1, except that the time for mixing and stirring the sodium trititanate fine powder and the silver nitrate aqueous solution was changed to 3 minutes. The amount of silver ions adsorbed by the silver-substituted sodium trititanate was 1.7 mmol / g.

[0060] [Comparative Example 1-1] An ion exchange reaction was attempted in the same manner as in Example 1-1, except that titanium dioxide TiO2 (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the raw material instead of sodium trititanate. The amount of silver ions adsorbed by TiO2 was 0.053 mmol / g.

[0061] [Comparative Example 1-2] An ion exchange reaction was attempted in the same manner as in Comparative Example 1-1, except that the concentration of the silver nitrate aqueous solution was changed to 100 mmol / L. The amount of silver ions adsorbed by TiO2 was 0.136 mmol / g.

[0062] [Comparative Example 1-3] An ion exchange reaction was attempted in the same manner as in Comparative Example 1-1, except that the concentration of the silver nitrate aqueous solution was changed to 200 mmol / L. The amount of silver ions adsorbed by TiO2 was 0.086 mmol / g.

[0063] [Comparative Example 1-4] An ion exchange reaction was attempted in the same manner as in Example 1-1, except that titanium dioxide TiO2 (Sigma-Aldrich) was used as the raw material instead of sodium trititanate. The amount of silver ions adsorbed by titanium dioxide TiO2 (Sigma-Aldrich) was 0.089 mmol / g.

[0064] [Comparative Example 1-5] An ion exchange reaction was attempted in the same manner as in Comparative Example 1-4, except that the concentration of the silver nitrate aqueous solution was changed to 100 mmol / L. The amount of silver ions adsorbed by titanium dioxide TiO2 (Sigma-Aldrich) was 0.226 mmol / g.

[0065] [Comparative Examples 1-6] An ion exchange reaction was attempted in the same manner as in Comparative Example 1-4, except that the concentration of the silver nitrate aqueous solution was changed to 200 mmol / L. The amount of silver ions adsorbed by titanium dioxide TiO2 (Sigma-Aldrich) was 0.188 mmol / g.

[0066] [Comparative Example 1-7] An ion exchange reaction was attempted in the same manner as in Example 1-1, except that metatitanic acid (titanium(IV) oxide monohydrate HTiO (manufactured by Mitsuwa Chemical Co., Ltd.) was used as the raw material instead of sodium trititanate. The amount of silver ions adsorbed by metatitanic acid was 0.178 mmol / g.

[0067] [Comparative Example 1-8] An ion exchange reaction was attempted in the same manner as in Comparative Example 1-7, except that the concentration of the silver nitrate aqueous solution was changed to 100 mmol / L. The amount of silver ions adsorbed by metatitanic acid was 0.352 mmol / g.

[0068] [Comparative Example 1-9] An ion exchange reaction was attempted in the same manner as in Comparative Example 1-7, except that the concentration of the silver nitrate aqueous solution was changed to 200 mmol / L. The amount of silver ions adsorbed by metatitanic acid was 0.073 mmol / g.

[0069] Thus, in Comparative Examples 1-1 to 1-9 using titanium dioxide or metatitanic acid as a raw material, the amount of silver ions adsorbed was very small compared to Examples 1-1 to 1-4 using sodium trititanate as a raw material. That is, for titanium oxides having a layered crystal structure such as sodium trititanate, silver ions easily enter the interlayer. On the other hand, it was suggested that silver ion entry and adsorption are less likely to occur in other titanium oxides.

[0070] [Example 2-1] In the same manner as in Example 1-1, pulverized sodium trititanate fine powder was obtained. To 10.0 g of the obtained sodium trititanate fine powder, 1 L of a 2 mmol / L silver nitrate AgNO3 aqueous solution was added, and the mixture was stirred at room temperature for 2 hours to perform ion exchange of the sodium trititanate fine powder. Thereafter, the reaction solution was filtered, washed, and dried to obtain silver-substituted sodium trititanate (Na 1-x Ag x )2Ti3O7 (0 < x < 1) fine powder. The amount of silver ions adsorbed by the silver-substituted sodium trititanate was about 0.2 mmol / g. 20 parts by mass of the obtained silver-substituted sodium trititanate fine powder adsorbed with 0.2 mmol / g of silver ions and 80 parts by mass (the value of the solid content other than the solvent) of a binder were mixed to obtain a coating material. A binder was applied on a polyethylene terephthalate (PET) film, and the above coating material was applied on the binder layer (i.e., the adhesive layer) to obtain a coating film. Using this coating film, an experiment was conducted to measure the antiviral activity value Mv against enveloped viruses according to Annex G of ISO 18184.

[0071] [Example 2-2] The antiviral activity value Mv was measured in the same manner as in Example 2-1, except that the coating material was directly applied on the PET film during the production of the coating film (i.e., the adhesive layer of Example 2-1 was not provided).

[0072] [Example 2-3] The antiviral activity value Mv was measured in the same manner as in Example 2-1, except that the concentration of the silver nitrate aqueous solution was 5 mmol / L. The amount of silver ions adsorbed by silver-substituted sodium trititanate was approximately 0.5 mmol / g.

[0073] [Example 2-4] The antiviral activity value Mv was measured in the same manner as in Example 2-3, except that the coating material was applied directly onto the PET film during production of the coating film.

[0074] [Comparative Example 2-1] The antiviral activity value Mv of a PET film coated with only the binder and without any coating material was measured in the same manner as in Example 2-1.

[0075] [Comparative Example 2-2] The antiviral activity value Mv of a PET film to which no binder or coating material was applied was measured in the same manner as in Example 2-1.

[0076] [Antiviral evaluation] The antiviral activity measurement results for Examples 2-1 to 2-4, Comparative Examples 2-1, and 2-2 are summarized in Table 1. Here, the entries in the Mv column indicate that "A" represents Mv≧3.0, "B" represents 3.0>Mv≧2.0, and "C" represents 2.0>Mv. According to ISO 18184 Annex G, if 2.0≦Mv<3.0, the measured sample is evaluated as having an antiviral effect, and if 3.0≦Mv, the measured sample is evaluated as having a sufficient antiviral effect. On the other hand, if Mv<2.0, it is evaluated as not having a significant antiviral effect.

[0077] [Table 1]

[0078] [Evaluation of photocatalytic properties] To evaluate the photocatalytic properties of silver-substituted sodium trititanate fine powder, its effect on promoting the decomposition of methylene blue was evaluated.

[0079] First, methylene blue was adsorbed onto silver-substituted sodium trititanate fine powder and a control sample (non-silver-substituted sodium trititanate fine powder). Specifically, 1 L of a 0.02 mmol / L methylene blue solution was prepared using methylene blue (manufactured by Waldeck GmbH & Co. KG). 0.5 g each of the silver-substituted sodium trititanate fine powder (silver ion adsorption amount: approximately 0.5 mmol / g) prepared under the conditions of Example 2-3 and non-ion-exchanged sodium trititanate fine powder (silver ion-free) were prepared and immersed in 250 mL of methylene blue solution at room temperature for 30 minutes. Using a suction filtration device, filtration and separation were performed using a filter with a pore size of 100 nm. The mixture was then dried at 100°C for 1 hour and recovered.

[0080] Next, the silver-substituted sodium trititanate fine powder (silver ion adsorption amount: approximately 0.5 mmol / g) adsorbed with methylene blue and the sodium trititanate fine powder were each placed in a black box and irradiated with black light (λ = 365 nm) for 0, 10, 20, 30, 60, or 120 minutes. After that, 0.1 g of the sample was placed in a diffuse reflectance measurement holder, and the absorbance of each sample at a wavelength of 673 nm was measured. The background was removed.

[0081] Figure 8 shows the time course of absorbance (673 nm) of methylene blue adsorbed onto the sample as an evaluation of photocatalytic properties. For unsilvered sodium trititanate fine powder, the absorbance measured at 20, 60, and 120 minutes after the start of irradiation was 72.7%, 57.5%, and 46.5%, respectively, based on the value at the start of irradiation. This means that the methylene blue decomposition rates were 27.3%, 42.5%, and 53.5%, respectively. On the other hand, for silver-substituted sodium trititanate fine powder with adsorbed silver ions, the absorbance measured at 20, 60, and 120 minutes after the start of irradiation was 41.0%, 27.3%, and 24.0%, respectively, based on the value at the start of irradiation. This means that the methylene blue decomposition rates were 59.0%, 72.7%, and 76.0%, respectively. Therefore, it is clear that silver substitution improves the effect of sodium trititanate fine powder in promoting the decomposition of methylene blue (i.e., photocatalytic properties). [Explanation of symbols]

[0082] 10, 20...antiviral member, 100, 200...substrate, 110...coating layer, 120, 220...particles, 130...binder.

Claims

1. An antiviral composition comprising a compound in which some of the sodium ions in sodium trititanate have been substituted with silver ions.

2. 2. The antiviral composition according to claim 1, wherein more than 0 atomic percent and up to 50 atomic percent of all sodium ions are substituted with silver ions.

3. 3. The antiviral composition of claim 2, wherein 5 atomic percent to 35 atomic percent of the total sodium ions are substituted with silver ions.

4. A coating material comprising the antiviral composition according to any one of claims 1 to 3 and a binder.

5. The coating material according to claim 4, comprising the compound in the form of particles, the median diameter of the particles being 0.1 μm or more and 100 μm or less.

6. The coating material according to claim 4 or 5, wherein a mass ratio of a content of the compound to a content of the solid content of the binder in the coating material is 0.01 or more and 1 or less.

7. A filter comprising the antiviral composition according to any one of claims 1 to 3.

8. A substrate; a coating layer formed on the surface of the substrate, the coating layer comprising the antiviral composition according to any one of claims 1 to 3; An antiviral member comprising:

9. A method for producing an antiviral composition containing a compound in which some of the sodium ions of sodium trititanate are substituted with silver ions, comprising: A method comprising mixing sodium trititanate with a solution containing silver ions.

10. 10. The method of claim 9, wherein the solution is an aqueous solution of one or more silver salts selected from the group consisting of silver nitrate, silver nitrite, silver sulfate, and silver acetate.

11. 11. The method of claim 9 or 10, wherein the sodium trititanate is mixed with the solution in the form of particles, the sodium trititanate particles having a median diameter of 0.1 μm or more and 500 μm or less.

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