Material, and filter with material

Abstract

The present invention provides: a material that has an excellent antiviral effect against various viruses even on a dry surface (in a gas phase) assumed as a condition under which a filter is actually used; and a filter with the material.　A material 3 according to the present disclosure comprises: a main body part 4 that has an uneven pattern on the surface; and nanodiamond particles 5 that are adhered to the uneven pattern. In addition, a filter 1 with a material according to the present disclosure is obtained by assembling the material 3 to a filter 2.

Description

Materials, filters with materials

[0001] The present disclosure relates to a material and a filter with the material. More specifically, the present disclosure relates to a material and a filter with the material that has a bacterial and viral removal effect and an antibacterial and antiviral effect. This application claims priority from Japanese Patent Application No. 2023-115890, filed on July 14, 2023, the contents of which are incorporated herein by reference.

[0002] Many viral diseases caused by viruses such as the new coronavirus, influenza virus, and norovirus are transmitted through a variety of routes, including droplet infection, droplet nuclei infection, and contact infection. Droplet nuclei infection is a route of infection in which very fine particles emitted by a patient remain suspended in the air for a long period of time, and people in the same space as the patient inhale the virus, which can particularly cause the spread of infection in small, enclosed spaces.

[0003] Incidentally, the novel coronavirus and influenza virus are enveloped viruses that have a lipid membrane, making them relatively less resistant to disinfection, such as by using lipid-soluble ethanol. On the other hand, norovirus is a non-enveloped virus that does not have an envelope, so ethanol disinfection alone is not effective and it is known to be a highly resistant virus, being resistant to drying and heating.

[0004] Furthermore, norovirus is so highly contagious that infection can occur with fewer than 100 virus particles, and it is known that droplet nuclei infection can occur when tiny amounts of vomit or feces from an infected person are dispersed into the air.

[0005] Conventionally, measures to prevent droplet nuclei infection have been taken to capture and remove airborne bacteria and viruses using filters. However, simply capturing bacteria and viruses on the filter has the problem that they remain infectious, and the filter itself can become a source of infection.

[0006] To overcome the above problems, filters that have antibacterial or antiviral effects against captured bacteria or viruses, or materials that can be attached to or detached from filters, are known.

[0007] Patent Document 1 discloses that by performing a zinc phosphate chemical conversion treatment on the surface of a metal substrate to form a zinc phosphate coating having micron-order irregularities on the surface, the zinc phosphate coating exhibits antifungal, bactericidal, and antiviral effects.

[0008] Nanodiamond particles are ultrafine diamond particles with a very large specific surface area, and due to their properties they are also used as antibacterial and antiviral ingredients.

[0009] Patent Document 2 discloses that when a dispersion containing nanodiamond particles is mixed with a solution containing influenza viruses, the dispersion containing the nanodiamond particles exhibits the effect of inactivating the influenza viruses.

[0010] Patent Document 3 discloses that applying a nonwoven fabric sheet impregnated with a coating liquid containing silver particles, diamond particles, ethanol, and water to a wall and / or ceiling provides an antiviral effect.

[0011] International Publication No. 2021 / 193843 Japanese Patent Application Laid-Open No. 2022-161727 Japanese Patent Application Laid-Open No. 2023-7158

[0012] However, although the material described in Patent Document 1 discloses an antiviral effect against bacteriophage Qβ under wet conditions (in a liquid phase), it does not disclose its effect against other viruses or its effect on a dry surface (in a gas phase), which is the expected condition under which the filter will actually be used, and there is room for further study.

[0013] Furthermore, Patent Document 2 discloses that the dispersion containing nanodiamond particles has an antiviral effect against influenza viruses under wet conditions (in the liquid phase), but does not disclose its effect against other viruses or its effect on dry surfaces (in the gas phase), which is the expected condition under which the filter will actually be used, and there is room for further study.

[0014] Furthermore, the antiviral nonwoven fabric sheet described in Patent Document 3 does not disclose any specific effects on viruses other than the novel coronavirus, nor any effects on dry surfaces (in the gas phase), which is the assumed condition under which the filter will actually be used.

[0015] Therefore, an object of the present disclosure is to provide a material and a filter with the material that exhibits excellent antiviral effects against various viruses.

[0016] As a result of intensive research into achieving the above object, the inventors of the present disclosure have found that the above material, which has a main body with an uneven surface and nanodiamond particles attached to the uneven surface, exhibits excellent antiviral effects against various viruses. The present disclosure has been completed based on these findings.

[0017] That is, the present disclosure provides a material comprising a main body having an uneven surface and nanodiamond particles attached to the uneven surface.

[0018] The main body preferably includes a substrate and a coating formed on the substrate.

[0019] The coating is preferably a zinc phosphate coating.

[0020] The nanodiamond particles preferably have a positive zeta potential.

[0021] The present disclosure also provides a filter with the material, in which the material is attached to a filter body.

[0022] The present disclosure also provides a nanodiamond particle dispersion for use in producing the above material.

[0023] The present disclosure also provides at least one product selected from the group consisting of a coating liquid, a plating liquid, and a chemical conversion treatment liquid, which contains the nanodiamond particle dispersion liquid used to prepare the material.

[0024] The material of the present disclosure, having the above-described configuration, can exhibit antiviral effects against various viruses. Furthermore, the present disclosure can provide a material-attached filter in which the material is assembled into a filter.

[0025] FIG. 1 is a schematic diagram of a material-equipped filter according to an embodiment of the present disclosure. FIG. 2 is an enlarged schematic diagram of a material according to an embodiment of the present disclosure. FIG. 3 is a diagram for explaining a procedure for calculating the distance between adjacent protrusions. FIG. 4 is a schematic diagram of a manufacturing process of a material according to an embodiment of the present disclosure. FIG. 5 is a scanning electron microscope photograph of a material manufactured in Comparative Example 1. FIG. 6 is a scanning electron microscope photograph of a material manufactured in Example 1. FIG. 7 is a scanning electron microscope photograph of a material manufactured in Example 2. FIG. 8 is a scanning electron microscope photograph of a material manufactured in Example 3. FIG. 9 is a scanning electron microscope photograph of a material manufactured in Example 4. FIG. 10 is a scanning electron microscope photograph of a material manufactured in Example 5.

[0026] In this specification, a filter having the above-mentioned material attached thereto may be referred to as a “material-attached filter.” Furthermore, in this specification, the effect evaluated by the “virus suppression performance evaluation test” described below, which is based on Annex F “Test method for evaluating suppression performance against viruses captured on a filter” of the Japan Electrical Manufacturers' Association standard JEM1467 “Household air purifiers,” may be referred to as the “antiviral effect.”

[0027] [Material and Material-Included Filter] The material according to one embodiment of the present disclosure has a configuration including a main body having an uneven surface, and nanodiamond particles attached to the uneven surface.

[0028] An embodiment of the material and the filter with the material of the present disclosure will be described below with reference to the drawings, but the material and the filter with the material of the present disclosure are not limited to this embodiment. Fig. 1 is a schematic diagram showing an embodiment of the filter with the material of the present disclosure.

[0029] 1 , the material-attached filter 1 includes a rectangular box-shaped filter body 2 and a mesh-like material 3 attached to the filter body 2 so as to cover at least a portion of the filter body 2. In this embodiment, the material 3 is attached to the filter body 2 so as to cover one entire surface of the filter body 2, but the present disclosure is not limited to this. It is sufficient that at least a portion of the filter body 2 is covered by the material 3. Furthermore, the filter body is not particularly limited, and a publicly known or commonly used filter can be used.

[0030] The material 3 includes a rectangular purification section 30 that is substantially the same shape as the filter body 2 in a plan view, and a first leg section 31 and a second leg section 32 that are strip-shaped and extend along opposing long sides of the four sides of the purification section 30. By including these legs, the material 3 is held by the filter body 2 and can be used as a single unit.

[0031] FIG. 2 is an enlarged schematic diagram of one embodiment of the material 3. The material 3 includes a main body 4 and nanodiamond particles 5. The main body 4 is composed of a substrate 41 and a coating 42. The substrate 41 is, for example, a mesh-shaped metal substrate, more specifically, an aluminum alloy mesh substrate containing A5056. A coating 42 is formed on the surface of the substrate 41. More specifically, a zinc phosphate coating with fine irregularities is formed by a zinc phosphate chemical conversion treatment described below, resulting in an irregular shape on the surface of the main body 4. Furthermore, nanodiamond particles 5 are attached to the surface of the coating 42 (the irregular surface of the main body 4) by a nanodiamond particle attachment treatment described below. Below, we will describe a case where the aluminum alloy mesh substrate is used as the substrate 41 and the zinc phosphate coating is used as the coating 42, but the present disclosure is not limited thereto.

[0032] (Main body portion) The main body portion preferably has at least a substrate. More preferably, the main body portion has the substrate and a coating formed on the substrate. The substrate and the coating may each be a single layer, or two or more layers may be laminated.

[0033] The substrate is not particularly limited, and known or commonly used metal substrates or resin substrates can be used. Examples of metal substrates include substrates made of aluminum, aluminum alloys containing aluminum as the main component and copper, manganese, silicon, magnesium, zinc, and nickel, iron, stainless steel, magnesium, magnesium alloys, titanium, titanium alloys, copper, copper alloys, nickel, nickel alloys, chromium, and chromium alloys. Examples of resin substrates include substrates made of polyolefin resins, polyolefin copolymer resins, polyester resins, acrylic resins, polyamide resins, polyimide resins, polycarbonate resins, phenolic resins, epoxy resins, silicone resins, styrene resins, fluorine resins, and urethane resins. The substrate may be made of one material, or two or more materials may be used.

[0034] The substrate is preferably a metal substrate from the viewpoints of durability and processability, and among these, a substrate made of aluminum or an aluminum alloy is more preferable from the viewpoints of lightness and processability, and a substrate made of an aluminum alloy is even more preferable.

[0035] The shape of the substrate is not particularly limited, and may be selected from, for example, a mesh shape, a flat plate shape, a nonwoven fabric shape, etc. Among these, a mesh shape is preferred from the viewpoint of not impairing the function of the filter body when assembled into the filter body.

[0036] The main body has an uneven surface, but the surface of the base material may be smooth or uneven. When the base material has an uneven surface, the unevenness may form the unevenness on the surface of the main body.

[0037] The thickness of the substrate is not particularly limited, and can be selected from thicknesses of, for example, 0.1 μm or more.

[0038] The coating has the ability to impart functions to the main body, such as antiviral, bactericidal, and antifungal effects, and the ability to adhere nanodiamond particles.

[0039] The coating is not particularly limited, and known or conventional coatings can be used. Examples include phosphate coatings such as zinc phosphate coating, manganese phosphate coating, iron phosphate coating, and calcium phosphate coating. Among these, zinc phosphate coatings are preferred because they have excellent antiviral effects, are easy to adjust the size of the irregularities, and allow nanodiamond particles to adhere easily. In addition, the coating may be provided on the substrate via another coating such as a zinc coating in order to improve adhesion to the substrate.

[0040] The thickness of the coating is not particularly limited and can be selected from thicknesses of, for example, 0.1 μm or more.

[0041] The main body portion has an uneven surface. The uneven surface may be present on the surface of the substrate, or on the coating. When the substrate surface has an uneven surface, the coating may be formed along the uneven surface so as to maintain the unevenness of the substrate surface. The main body portion 4 in Figure 2 has an uneven coating 42 formed on the flat surface of a substrate 41.

[0042] The spacing between the convex portions of the unevenness of the main body is preferably 0.5 to 50.0 μm, more preferably 0.5 to 6.0 μm, from the viewpoints of excellent antiviral effect, ease of adjusting the size of the unevenness, and ease of attachment of nanodiamond particles. The spacing between the convex portions can be calculated using the procedure described below.

[0043] 3 is a diagram illustrating a procedure for calculating the distance between adjacent protrusions. As shown in FIG. 3, countless blade-like protrusions 42a (bright portions in FIG. 3) with irregular orientations are formed on the surface of the zinc phosphate coating 42. As a result, countless recesses 42b (dark portions in FIG. 3) are formed on the surface of the zinc phosphate coating 42 as concave spaces defined by the countless protrusions 42a.

[0044] In this specification, the length of one side of each recess 42b in a planar view is defined as the spacing between adjacent protrusions 42a in a planar view. More specifically, the shape of each recess 42b formed on the surface of the zinc phosphate coating 42 in a planar view is considered to be a shape (e.g., rectangular or elliptical) that can define a longitudinal direction LD and a transverse direction SD perpendicular to the longitudinal direction LD. The longitudinal direction LD and the transverse direction SD perpendicular to the longitudinal direction LD are defined for each recess 42b, and the length of each recess 42b along the longitudinal direction LD and the transverse direction SD is defined as the spacing between adjacent protrusions 42a. Based on the above definition, the lengths of each recess 42b along the longitudinal direction LD and the transverse direction SD are calculated, and the minimum value of the length along the transverse direction SD is defined as the minimum spacing between the protrusions 42a, and the maximum value of the length along the longitudinal direction LD is defined as the maximum spacing between the protrusions 42a.

[0045] The thickness of the main body is not particularly limited and can be selected from thicknesses of, for example, 0.1 μm or more. From the viewpoint of stably forming the concave-convex shape, the thickness is preferably 0.1 μm or more, more preferably 0.25 μm or more, and even more preferably 0.5 μm or more.

[0046] (Nanodiamond particles) In this specification, "nanodiamond particles" refers to diamond particles whose primary particle size (average primary particle diameter) is less than 1000 nm. The average primary particle diameter of the nanodiamond particles is preferably, for example, 100 nm or less, more preferably 60 nm or less, even more preferably 50 nm or less, and particularly preferably 30 nm or less. The lower limit of the average primary particle diameter of the nanodiamond particles may be, for example, 1 nm.

[0047] The nanodiamond particles are not particularly limited, and known or conventional nanodiamond particles can be used. The nanodiamond particles may be surface-modified or unmodified. Unmodified nanodiamond particles have many hydroxyl groups (-OH) and carboxyl groups (-COOH) on their surfaces. Only one type of nanodiamond particle may be used, or two or more types may be used.

[0048] In the above-mentioned surface-modified nanodiamond particles, the compound or functional group that modifies the surface of the nanodiamond particles is not particularly limited, and examples thereof include hydrogen groups (C-H groups), silane compounds, phosphonate ions or phosphonate residues, surface-modifying groups having a vinyl group at the end, amide groups, cations of cationic surfactants, groups containing polyglycerin chains, and groups containing polyethylene glycol chains.

[0049] From the viewpoint of antiviral effect, it is preferable that the nanodiamond particles have at least a hydrogen group, a hydroxy group, or a carboxy group on the surface.

[0050] The zeta potential of the nanodiamond particles may be negative or positive. Note that nanodiamond particles that have many hydroxyl groups or carboxyl groups on the surface, such as nanodiamond particles that are not surface-modified, tend to have a negative zeta potential due to the oxygen-based functional groups. On the other hand, nanodiamond particles that have many hydrogen groups on the surface, for example, through reduction treatment such as hydrogenation, tend to have a positive zeta potential due to surface termination with hydrogen. In particular, it is preferable that the zeta potential of the nanodiamond particles is positive. By using nanodiamond particles with a positive zeta potential, the antiviral effect against a wide range of viruses tends to be sufficient.

[0051] In this specification, the zeta potential of the nanodiamond particles is negative, and the zeta potential of the nanodiamond particles is negative when the dispersion medium has a pH of 5 to 9 and an ionic strength of 1.0 × 10 at 25 ° C., as measured by, for example, laser Doppler electrophoresis. －４ This means that the zeta potential at M is a negative value. The zeta potential is, for example, preferably −80 to −5 mV, more preferably −70 to −10 mV, and even more preferably −60 to −20 mV.

[0052] In this specification, the zeta potential of the nanodiamond particles is positive, and the zeta potential of the nanodiamond particles is positive when the dispersion medium has a pH of 5 to 9 and an ionic strength of 1.0 × 10 at 25 ° C., as measured by, for example, laser Doppler electrophoresis. －４This means that the zeta potential at M is a positive value. The zeta potential is, for example, preferably 5 to 80 mV, more preferably 10 to 70 mV, and even more preferably 20 to 60 mV.

[0053] The average primary particle diameter (D50) of the nanodiamond particles is preferably 100 nm or less, more preferably 60 nm or less, even more preferably 50 nm or less, and particularly preferably 30 nm or less. The lower limit of the average primary particle diameter of the nanodiamond particles may be, for example, 1 nm. When the average primary particle diameter is 100 nm or less, the nanodiamond particles can be more densely attached to the coating surface. The average primary particle diameter can be measured by image analysis (electron microscope measurement such as TEM or SEM) in a powder state or by X-ray diffraction. In the case of electron microscope measurement, the particle size distribution (number basis) of the equivalent circle diameter based on electron microscope observation can be determined as the particle size corresponding to the cumulative 50% from the smallest particle size side. Note that when the nanodiamond particles are approximately spherical, the average value of the longest diameter can also be used as the average primary particle diameter.

[0054] The nanodiamond particles may adhere to the surface of the main body in a dispersed state, or in the form of secondary particles (aggregates) consisting of multiple aggregates of primary particles. The size of the secondary particles (average secondary particle diameter) is approximately 10 to 200 times the average particle diameter of the primary particles. The average secondary particle diameter is preferably 50 to 1,000 nm, more preferably 50 to 500 nm, even more preferably 50 to 200 nm, and particularly preferably 50 to 100 nm. When the average secondary particle diameter is within this range, the secondary particles are less likely to settle during the nanodiamond particle adhesion treatment process described below, allowing for uniform adhesion to the coating surface. The adhesion pattern can be observed by image analysis (electron microscope measurement such as TEM or SEM).

[0055] The coating amount (A) of the nanodiamond particles per surface area of ​​the material is preferably 0.02 mg / cm ２ More preferably, it is 0.05 mg / cm ２or more, more preferably 0.1 mg / cm ２ More preferably, it is 0.2 mg / cm ２ The amount of nanodiamond particles applied per surface area of ​​the material (A) is preferably 1 mg / cm ２ or less, more preferably 0.7 mg / cm ２ More preferably, it is 0.5 mg / cm or less. ２ or less, and particularly preferably 0.4 mg / cm ２ Here, the coating amount (A) is calculated by the procedure described below. The coating amount can be adjusted by changing the concentration of nanodiamond particles in the nanodiamond particle dispersion liquid or the solvent of the dispersion liquid in the nanodiamond particle adhesion treatment described below.

[0056] As the above-mentioned nanodiamond particle, for example, can use detonation nanodiamond (i.e., the nanodiamond produced by detonation method), high-temperature high-pressure nanodiamond (i.e., the bulk diamond produced by high-temperature high-pressure method is crushed into nanoparticles), or chemical vapor deposition nanodiamond (i.e., the thin film diamond obtained by chemical vapor deposition is crushed into nanoparticles).Among them, detonation nanodiamond is preferred because the particle diameter of primary particle is single-digit nanometer.

[0057] The detonation nanodiamond includes air-cooled detonation nanodiamond (i.e., nanodiamond produced by air-cooled detonation method) and water-cooled detonation nanodiamond (i.e., nanodiamond produced by water-cooled detonation method).Among them, air-cooled detonation nanodiamond is preferred because the size of the primary particle is smaller than that of water-cooled detonation nanodiamond.In addition, the nanodiamond particle may be the primary particle of nanodiamond, or may be the secondary particle that a plurality of the primary particles are aggregated (adhered).

[0058] In embodiments of the materials disclosed herein, the materials may be assembled into known or conventional filter bodies to form filters. Such filters may be used in automotive air conditioners, air conditioners, air purifiers, and the like.

[0059] In an embodiment of the material of the present disclosure, the conditions for using the material-attached filter are not particularly limited, and the filter can be used, for example, in any of the gas phase, liquid phase, and solid phase. Of these, use in the gas phase is preferred, as this makes it easier for the material to exert its effects. Furthermore, the state of each of the phases is not particularly limited. For example, in the gas phase, there are no limitations on the type of gas, temperature, humidity, or pressure. However, when used in the automotive air conditioning system, air conditioner, air purifier, etc., use in air at room temperature and normal pressure is an example.

[0060] The material of the present disclosure has a main body having micron-order irregularities and nanodiamond particles, and thereby exhibits antiviral effects against various viruses. Examples of viruses include enveloped and non-enveloped viruses. The material exhibits excellent antiviral effects against non-enveloped viruses, particularly feline calicivirus. From the perspective of infection prevention measures, a log reduction value of 1.0 or more is preferred, and a log reduction value of 2.0 or more is even more preferred, in the test method for evaluating the inhibitory performance against feline calicivirus described below.

[0061] Micron-order irregularities are thought to exert a bactericidal effect due to physical effects resulting from their shape (e.g., bacteria impaling on the irregularities deforms the cell wall itself, killing them). Meanwhile, for example, influenza viruses are 80-120 nm in size, and feline caliciviruses are 27-35 nm in size, about one-tenth the size of typical bacteria (0.5-2 μm). Therefore, viruses have difficulty penetrating micron-order irregularities, potentially making it difficult for antiviral effects to be exerted. Therefore, the material disclosed herein is thought to be able to exert a combined effect derived from the irregular shape and nanodiamond particles by stably attaching a large number of nanodiamond particles by utilizing the large specific surface area provided by the irregularities, such that the nanodiamond particles act even on viruses that have entered the recesses of the irregularities. Therefore, the material disclosed herein, with its configuration as described above, is thought to be able to exhibit excellent antibacterial and antiviral effects against microorganisms of various sizes.

[0062] In embodiments of the material disclosed herein, a material having at least one of an antiviral effect, an antibacterial effect, and an antifungal effect may be specifically referred to as a "functional material." Here, the definition of each effect may refer to a general definition in the art. "Antiviral effect" refers to an effect evaluated, for example, by ISO 21702:2019 Measurement of antiviral activity on plastics and other non-porous surfaces. "Antibacterial effect" refers to an effect evaluated, for example, by JIS Z 2801:2012 "Antibacterial processed products - Antibacterial test method, antibacterial effect." "Antifungal effect" refers to an effect evaluated, for example, by JIS Z 2911:2018 "Mold resistance test method."

[0063] [Material manufacturing method] The above material can be produced by attaching nanodiamond particles to the main body by a known or conventional method. For example, the above material can be produced by applying a nanodiamond particle dispersion to the main body and drying it to attach nanodiamond particles. When the main body has the substrate and the coating, the substrate is treated to form a coating with fine irregularities on the metal surface, and then the nanodiamond particle dispersion is applied and dried to attach the nanodiamond particles.

[0064] The following describes a manufacturing method for material 3 shown in FIG. 2 as an example. FIG. 4 is a schematic diagram of the manufacturing process for one embodiment of material 3. As shown in FIG. 4, material 3 can be manufactured, for example, by subjecting a substrate 41 to a cleaning process, a surface conditioning process, a zinc phosphate chemical conversion treatment, and a nanodiamond particle attachment process. More specifically, the process includes cleaning, degreasing, and rinsing a substrate 41 (e.g., an aluminum alloy mesh substrate) processed into a shape suitable for assembly into a filter body; a surface conditioning process in which the substrate 41 is immersed in a surface conditioning solution to form nuclei that serve as triggers for crystallization on its surface; a zinc phosphate chemical conversion treatment in which the substrate 41 is contacted with a zinc phosphate treatment solution for a predetermined time to form a coating 42, which is a zinc phosphate coating having micron-order irregularities, on the surface of the substrate 41; and a process in which the substrate is immersed in a nanodiamond particle dispersion for a predetermined time and then dried to attach a plurality of nanodiamond particles 5 to the surface of the coating 42.

[0065] 4 shows the case of zinc phosphate conversion treatment, but the present disclosure is not limited thereto. For example, other phosphate conversion treatments (manganese phosphate conversion treatment, iron phosphate conversion treatment, calcium phosphate conversion treatment), conversion treatments such as boehmite treatment, chromate treatment, and zincate treatment, and surface treatments such as plasma treatment and blast treatment may also be used. Among these, zinc phosphate conversion treatment is preferred from the viewpoint of ease of adjusting the size of the unevenness.

[0066] In this specification, micron-order irregularities refer to a state in which the spacing between adjacent protrusions calculated by the procedure described in FIG. 3 is within the range of 0.1 to 1000 μm, and an infinite number of irregularities are formed by such protrusions.

[0067] (Surface Conditioning Step) The surface conditioning step is not particularly limited, and a known or conventional surface conditioning solution can be used. For example, "PL-X" or "PL-XG" manufactured by Nihon Parkerizing Co., Ltd., adjusted to a predetermined concentration [g / L], can be used. By changing the concentration of the surface conditioning solution, it is possible to change the unevenness formed on the surface of the metal substrate between coarse and fine. The higher the concentration of the surface conditioning solution, the finer the unevenness tends to be. From the viewpoint of forming micron-order unevenness, the concentration of the surface conditioning solution is preferably 0.1 g / L or more, more preferably 1.0 g / L or more, and even more preferably 2.0 g / L or more. From the viewpoint of cost-effectiveness, the concentration of the surface conditioning solution is preferably 10 g / L or less, more preferably 5.0 g / L or less.

[0068] (Zinc phosphate chemical conversion treatment) The zinc phosphate chemical conversion treatment is not particularly limited, and a known or commonly used zinc phosphate treatment solution can be used, such as "PB-LA37," "Palbond 880," or "Ferricote 7" manufactured by Nihon Parkerizing Co., Ltd.

[0069] (Nanodiamond particle adhesion treatment) The nanodiamond particle dispersion liquid used in the above nanodiamond particle adhesion treatment contains nanodiamond particles and a solvent. The concentration of nanodiamond particles in the nanodiamond particle dispersion liquid is preferably 0.01 to 10 mass%, more preferably 0.05 to 5 mass%, and even more preferably 0.1 to 2 mass%. When the concentration of nanodiamond particles in the nanodiamond particle dispersion liquid is 0.01 mass% or more, the amount of nanodiamond particles attached is sufficient, and it is easy to obtain a sufficient antiviral effect.

[0070] Examples of the solvent for the nanodiamond particle dispersion include water, ethanol, methanol, isopropanol, isobutyl alcohol, ethylene glycol, propylene glycol, glycerin, 2-methoxyethanol, dimethyl sulfoxide, N-methyl-2-pyrrolidone, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, hexamethylphosphoramide, dimethyl sulfone, and propylene carbonate. These solvents may be used alone or in combination. From the standpoints of safety, ease of handling, and dispersibility, it is preferable for the solvent to contain at least water, and a mixed solvent of water and ethanol is more preferable.

[0071] The nanodiamond particle dispersion may be contained in various products. Examples include coating solutions, plating solutions, and chemical conversion treatment solutions. The concentration of nanodiamond particles contained in the products is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and even more preferably 0.1 to 2% by mass. When the concentration of nanodiamond particles in the nanodiamond particle dispersion is 0.01% by mass or more, the amount of nanodiamond particles attached is sufficient, making it easier to achieve a sufficient antiviral effect.

[0072] In the above-mentioned nanodiamond particle adhesion treatment, the method of adhesion of nanodiamond particles (coating method) is not particularly limited, and known or conventional coating methods can be used.For example, dip coating method, spray coating method, roller coating method, slit coating method, spin coating method, etc. are listed.Among them, dip coating method is preferred from the viewpoint of good adhesion efficiency.

[0073] In the above-mentioned nanodiamond particle adhesion treatment, the drying method is not particularly limited, and known or conventional drying methods can be used.For example, natural drying, vacuum drying, drying under a specific gas environment (the type of gas is not particularly limited, for example, argon, nitrogen, etc.), air blowing, heat drying, etc. can be mentioned.Since the purpose is to dry the solvent, natural drying is sufficient, but heat drying at about 100 ° C can also be used depending on the heat resistance of the substrate.

[0074] Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. Furthermore, each invention according to this disclosure is not limited by the embodiments or the following examples, but is limited only by the scope of the claims.

[0075] Hereinafter, one embodiment of the present disclosure will be described in more detail based on examples.

[0076] Comparative Example 1 (Method of Producing Material) A material was produced by subjecting an aluminum alloy mesh substrate containing A5056 to the steps shown in the schematic diagram of Fig. 4. More specifically, an aluminum alloy mesh substrate having a wire diameter of 0.25 µm, a mesh pore diameter of 0.596 µm, and a pitch of 0.8467 µm was washed, and then subjected to a surface conditioning step of immersing the substrate in a surface conditioning solution with a concentration of 3 g / L, and a zinc phosphate conversion treatment step of immersing the substrate in a zinc phosphate treatment solution "PB-LA37" to produce a material.

[0077] Example 1 The material prepared in Comparative Example 1 was subjected to the following steps to prepare a material.

[0078] (Preparation process of nanodiamond particle dispersion) 103.4 g of ζ (+) nanodiamond raw material solution (trade name "Dinobear", manufactured by Daicel Corporation, nanodiamond particle concentration contained in the raw material solution: 2.91 mass%, zeta potential at pH 3.0: +40 mV) was weighed into a container, 1.9 g of water as a solvent and 45.0 g of ethanol were added, and the mixture was stirred at room temperature to prepare 150 g of nanodiamond particle dispersion in which the nanodiamond particles were uniformly dispersed. At this time, the nanodiamond particle concentration contained in the nanodiamond particle dispersion was 2.0 mass%.

[0079] (Nanodiamond particle attachment treatment) 150 g of the obtained nanodiamond particle dispersion was placed in a flat-bottomed metal container, and one sheet of material prepared using the procedure of Comparative Example 1 was impregnated and dipped for 10 seconds. The sheet was then removed from the nanodiamond particle dispersion, tilted in the air, and left to stand for 30 seconds. Excess dispersion was then removed, and the sheet was air-dried at room temperature for 3 hours to produce a material with nanodiamond particles attached.

[0080] Examples 2 to 5 Materials with nanodiamond particles attached were prepared in the same manner as in Example 1, except that the nanodiamond particle dispersion liquid shown in Table 1 was used. In Examples 4 to 5, a ζ(-) nanodiamond raw material liquid (trade name "Dinobear", manufactured by Daicel Corporation, nanodiamond particle concentration contained in the raw material liquid: 5.68%, zeta potential at pH 9.0: -35 mV) was used as the nanodiamond raw material liquid. Note that the numerical values ​​for the composition of the nanodiamond particle dispersion liquid in Table 1 refer to "g."

[0081] The surface condition of the material produced by the above process was observed using the "Surface Condition Observation Method" described below, and the results are shown in Figures 5 to 10. Note that all are backscattered electron images at 20,000x magnification. Figure 5 for Comparative Example 1 confirms the formation of a zinc phosphate coating with micron-order irregularities, while Figures 6 to 10 for Examples 1 to 5 confirm the adhesion of nanodiamond particles to the irregularities of the zinc phosphate coating.

[0082] The materials prepared by the above steps were evaluated in the "Test for evaluating the performance of inhibiting viruses" described below, and the results are shown in Table 1.

[0083] [Evaluation] (Test to evaluate virus suppression performance) In order to evaluate the antiviral effect against viruses captured on the surface of a material, a test was conducted under the following conditions, with reference to Annex F "Test method for evaluating suppression performance against viruses captured on a filter" of the Japan Electrical Manufacturers' Association standard JEM1467 "Home air purifier." In all tests, the following materials were used as test or control products.

[0084] Test sample: a piece (5 x 5 cm) of the material of each Example or Comparative Example 1 Control sample: a glass plate (5 x 5 cm)

[0085] The viruses used were influenza A virus, which is designated as an indicator virus in the above-mentioned "Test method for evaluating the performance of suppressing viruses captured on a filter," and Escherichia coli phage, as well as feline calicivirus, which is known as a substitute for norovirus. Since norovirus, which infects humans, is difficult to culture and a method for experimental evaluation has not yet been established, feline calicivirus, which is structurally similar to and closely related to norovirus, was used.

[0086] (Test method for evaluating inhibitory performance against influenza A virus) The following viruses and host cells were used. Influenza A virus: Influenza A virus, H1N1, A / PR / 8 / 34 (ATCC VR-1469) Host cells: MDCK cells (canine kidney cells) (ATCC CCL-34) (1) 0.1 mL of influenza A virus liquid was dropped onto the control product. (2) The control product (1) was immediately washed out with MEM (Minimum Essential Medium), PBS (Phosphate Buffered Saline), or sterile ion-exchanged water, and the virus on the control product was recovered. The solution obtained by this process was used as the 0-second action virus solution of the control product. (3) The control product (2) was left to stand in the test chamber, and after 24 hours, it was washed out with MEM, PBS, or sterile ion-exchanged water, and the virus on the control product was recovered. The solution obtained through this process was used as the 24-hour active virus solution of the control product. (4) 0.1 mL of influenza A virus liquid was dropped onto the test product of each Example and Comparative Example. (5) The test product (4) was left to stand in the test chamber, and after 24 hours, it was washed out with MEM, PBS, or sterile ion-exchanged water, and the virus on the control product was recovered. The solution obtained through this process was used as the 24-hour active virus solution of the test product. (6) The recovered 0-second active virus solution of the control product, the 24-hour active virus solution of the control product, and the 24-hour active virus solution of the test product were used as sample stock solutions, and 10-fold serial dilutions were prepared with MEM, PBS, or sterile ion-exchanged water. (7) 100 μL of the sample stock solution or diluted solution and 100 μL of MDCK cells suspended in MDCK cell medium were inoculated into a 96-well plate. (8) After culturing (7) in a carbon dioxide incubator, the cytopathogenic effect (CPE) was confirmed under a microscope, and the influenza A virus infectivity titer per 1 mL of the washout solution was determined using the Reed-Muench method.

[0087] (Test method for evaluating inhibitory performance against feline calicivirus) The following viruses and host cells were used. Feline calicivirus: Feline calicivirus, F-9 (ATCC VR-782) Host cells: CRFK cells (a feline kidney-derived cell line) (ATCC CCL-94) (1) 0.1 mL of feline calicivirus solution was dropped onto the control product. (2) The control product (1) was immediately washed out with MEM, PBS, or sterile ion-exchanged water, and the virus on the control product was recovered. The solution obtained by this process was used as the 0-second active virus solution of the control product. (3) The control product (2) was left to stand in the test chamber, and after 24 hours, it was washed out with MEM, PBS, or sterile ion-exchanged water, and the virus on the control product was recovered. The solution obtained by this process was used as the 24-hour active virus solution of the control product. (4) 0.1 mL of feline calicivirus solution was dropped onto the test samples of each Example and Comparative Example. (5) The test samples in (4) were left stationary in the test chamber, and after 24 hours, they were washed with MEM, PBS, or sterile ion-exchanged water to recover the virus on the control samples. The solution obtained through this process was used as the 24-hour active virus solution of the test sample. (6) The recovered 0-second active virus solution of the control sample, the 24-hour active virus solution of the control sample, and the 24-hour active virus solution of the test sample were used as sample stock solutions, and 10-fold serial dilutions were prepared with MEM, PBS, or sterile ion-exchanged water. (7) 100 μL of the sample stock solution or diluted solution and 100 μL of CRFK cells suspended in CRFK cell medium were planted into a 96-well plate. (8) (7) was cultured in a carbon dioxide incubator, and then the cytopathogenic effect (CPE) was confirmed under a microscope, and the feline calicivirus infectivity titer per mL of the washout solution was determined using the Reed-Muench method.

[0088] (Test for evaluating virus suppression performance against Escherichia coli phage) The following viruses and host bacteria were used. Escherichia coli phage: Escherichia coli phage MS2 (NBRC 102619) Host bacteria: Escherichia coli (NBRC 3012) (1) 0.1 mL of Escherichia coli phage solution was dropped onto the control product. (2) The control product (1) was immediately washed with MEM, PBS, or sterile ion-exchanged water, and the virus on the control product was recovered. The solution obtained by this process was used as the 0-second active virus solution of the control product. (3) The control product (2) was left to stand in the test chamber, and after 24 hours, it was washed with MEM, PBS, or sterile ion-exchanged water, and the virus on the control product was recovered. The solution obtained by this process was used as the 24-hour active virus solution of the control product. (4) 0.1 mL of E. coli phage solution was dropped onto the test sample of each Example and Comparative Example. (5) The test sample (4) was left to stand in the test chamber, and after 24 hours, it was washed with MEM, PBS, or sterile ion-exchanged water to recover the virus on the control sample. The solution obtained through this process was the 24-hour active virus solution of the test sample. (6) The recovered 0-second active virus solution of the control sample, the 24-hour active virus solution of the control sample, and the 24-hour active virus solution of the test sample were used as sample stock solutions, and a 10-fold serial dilution series was prepared with MEM, PBS, or sterile ion-exchanged water. (7) The sample stock solution or diluted solution was mixed with E. coli liquid medium in which E. coli had been cultured, and the mixture was allowed to stand at 35±1°C for 10 to 20 minutes. (8) Soft NB agar medium at 45 to 50°C was added to the solution (7), mixed, and layered on the lower medium of a square Petri dish for immobilization. (9) (8) was inverted and cultured at 35±1°C for approximately 16 to 24 hours, after which the number of plaques formed on the medium was counted and the number of phages per mL of the washout solution was calculated. The washout solution was sterilized by filtration.

[0089] (Evaluation of antiviral effect) Based on the above test results, the logarithmic reduction in virus infectivity or phage count was calculated as an index of antiviral effect using the following formula (1): R = Log (B / A) (1) R: logarithmic reduction in virus infectivity or phage count (antiviral effect) A: virus infectivity or phage count of control product (glass plate) after 24 hours of action B: virus infectivity or phage count of test product (section of nanodiamond particle-containing cover of each example or cover of comparative example) after 24 hours of action

[0090] In this specification, the antiviral effect was judged based on the following criteria. That is, evaluation A was judged as "sufficient antiviral effect", evaluation B was judged as "antiviral effect", and evaluation C was judged as "no antiviral effect". A: logarithmic reduction value of 2.0 or more (sufficient antiviral effect) B: logarithmic reduction value of 1.0 or more and less than 2.0 (antiviral effect) C: logarithmic reduction value of less than 1.0 (no antiviral effect)

[0091] In JEM1467 "Home Air Purifiers" Annex F "Test Methods for Evaluating Inhibitory Performance Against Viruses Captured on Filters" (for bacteria and mold, refer to this standard), in all microbial tests, each microbial liquid was dropped onto the test product and allowed to dry naturally immediately before the start of the test, and the microbial liquid was allowed to act in its dried state for 24 hours, so the results obtained from this test are considered to be the antiviral (or antibacterial, antifungal) effect on a dry surface (in the gas phase).

[0092] (Method for measuring zeta potential) The zeta potential of the nanodiamond particles contained in the nanodiamond particle dispersion was measured by laser Doppler electrophoresis using a Malvern device (trade name "Zetasizer Nano ZS"). When measuring the zeta potential, the nanodiamond particles contained in the nanodiamond particle dispersion were subjected to a dispersion treatment (for example, ultrasonic treatment) so that the average particle diameter (D50) of the nanodiamond particles was 100 nm or less. In addition, the pH of the nanodiamond particle dispersion was confirmed using pH test paper (trade name "Three-Band pH Test Paper", manufactured by AS ONE Corporation).

[0093] (Method for Observing Surface Condition) The surface of the above material was observed using a scanning electron microscope (SEM) (product name "SU5000") manufactured by Hitachi High-Technologies Corporation. The measurement conditions were an acceleration voltage of 3.0 kV, a spot intensity of 30, and conductive treatment with Pt.

[0094] (Method for calculating the amount of nanodiamond particles applied) The amount of nanodiamond particles applied (A) per surface area of ​​the material is calculated from the weight gain (X) and the surface area (Y) of the material, as shown in the following formula (2). The weight gain (X) is calculated by subtracting the weight before application from the weight after application in the nanodiamond particle attachment process (here, the weight after application refers to the weight after the material has dried after the application process). The surface area (Y) of the material is the surface area calculated assuming that the surface is smooth. That is, for example, if the material is a rectangular flat plate, the area of ​​the rectangle calculated by multiplying the short side of the rectangle by the long side corresponds to the surface area (Y) of the material. A = X / Y (2)

[0095]

[0096] Table 1 shows that the material of the present disclosure exhibits excellent antiviral effects against various viruses even on dry surfaces, which are the conditions expected for actual use of filters.

[0097] Variations of the invention according to the present disclosure are described below. [Appendix 1] A material comprising a main body having an uneven surface and nanodiamond particles adhered to the uneven surface. [Appendix 2] The material according to Appendix 1, wherein the main body includes a substrate and a coating formed on the substrate. [Appendix 3] The material according to Appendix 2, wherein the substrate is a metal substrate. [Appendix 4] The material according to Appendix 3, wherein the metal substrate is a substrate made of aluminum or an aluminum alloy. [Appendix 5] The material according to Appendix 3 or 4, wherein the metal substrate is a substrate made of an aluminum alloy. [Appendix 6] The material according to any one of Appendixes 2 to 5, wherein the substrate has a mesh, plate, or nonwoven fabric shape. [Appendix 7] The material according to any one of Appendixes 2 to 6, wherein the substrate has a mesh shape. [Appendix 8] The material according to any one of Appendixes 2 to 7, wherein the substrate has a thickness of 0.1 μm or more. [Appendix 9] The material according to any one of Appendices 2 to 8, wherein the coating is a phosphate coating. [Appendix 10] The material according to any one of Appendices 2 to 9, wherein the coating is a zinc phosphate coating. [Appendix 11] The material according to any one of Appendices 2 to 10, wherein the thickness of the coating is 0.1 μm or more. [Appendix 12] The material according to any one of Appendices 2 to 11, wherein the uneven shape is present at least in the coating. [Appendix 13] The material according to any one of Appendices 1 to 12, wherein the spacing between convex portions in the unevenness is 0.5 to 50.0 μm. [Appendix 14] The material according to any one of Appendices 1 to 13, wherein the thickness of the main body is 0.1 μm or more. [Appendix 15] The material according to any one of Appendices 1 to 14, wherein the average primary particle size of the nanodiamond particles is 100 nm or less. [Appendix 16] The material of any one of Appendices 1 to 15, wherein the lower limit of the average primary particle size of the nanodiamond particles is 1 nm. [Appendix 17] The material of any one of Appendices 1 to 16, wherein the nanodiamond particles comprise surface-modified nanodiamond particles. [Appendix 18] The material of any one of Appendices 1 to 17, wherein the nanodiamond particles comprise non-surface-modified nanodiamond particles. [Appendix 19] The material of any one of Appendices 1 to 18, wherein the nanodiamond particles have at least a hydrogen group, a hydroxy group, or a carboxy group on their surface.[Appendix 20] The material of any one of Appendices 1 to 19, wherein the nanodiamond particles have a positive zeta potential. [Appendix 21] The material of any one of Appendices 1 to 21, wherein the nanodiamond particles have a zeta potential of 5 to 80 mV. [Appendix 22] The coating amount of the nanodiamond particles per surface area is 0.02 mg / cm. ２ The material according to any one of claims 1 to 21, wherein the amount of nanodiamond particles applied per surface area is 1 mg / cm. ２The material of any one of Appendixes 1 to 22, wherein the nanodiamond particles are detonation nanodiamonds. [Appendix 24] The material of any one of Appendixes 1 to 23, wherein the nanodiamond particles are detonation nanodiamonds. [Appendix 25] The material of Appendix 24, wherein the detonation nanodiamonds are air-cooled detonation nanodiamonds. [Appendix 26] The material of Appendix 24, wherein the detonation nanodiamonds are water-cooled detonation nanodiamonds. [Appendix 27] The material of any one of Appendixes 1 to 26, wherein the material has at least one effect selected from the group consisting of an antiviral effect, an antibacterial effect, and an antifungal effect. [Appendix 28] The material of any one of Appendixes 1 to 27, wherein the material has an antiviral effect. [Appendix 29] The material of Appendix 27 or 28, wherein the virus is an enveloped virus. [Appendix 30] The material of Appendix 29, wherein the enveloped virus is an influenza virus. [Appendix 31] The material of Appendix 27 or 28, wherein the virus is a non-enveloped virus. [Appendix 32] The material according to Appendix 31, wherein the non-enveloped virus is feline calicivirus. [Appendix 33] The material according to Appendix 32, wherein the log reduction in feline calicivirus infectivity titer evaluated according to ISO 21702:2019 is 1.0 or more. [Appendix 34] A filter with a material, comprising a material according to any one of Appendixes 1 to 33 attached to the filter. [Appendix 35] A filter with the material according to Appendix 34 for use in a gas phase. [Appendix 36] A filter with the material according to Appendix 34 or 35 for use in an automotive air conditioner, air conditioner, or air purifier. [Appendix 37] A nanodiamond particle dispersion used in the production of the material according to any one of Appendixes 1 to 33, the nanodiamond particle dispersion comprising the nanodiamond particles and a solvent in which the nanodiamond particles are dispersed, the solvent comprising at least water, and the nanodiamond particles contained in the nanodiamond particle dispersion at a concentration of 0.01 to 10 mass%. [Appendix 38] At least one product selected from the group consisting of a coating liquid, a plating liquid, and a chemical conversion treatment liquid, comprising the nanodiamond particle dispersion liquid described in Appendix 37.

[0098] REFERENCE SIGNS LIST 1 Material-attached filter 2 Filter body 3 Material 30 Purification section 31 First leg section 32 Second leg section 4 Body section 41 Substrate 42 Coating 42a Convex section 42b Concave section 5 Nanodiamond particles

Claims

1. A material comprising a main body having a surface irregularity and nanodiamond particles attached to the surface irregularities.

2. The material of claim 1, wherein the body portion includes a substrate and a coating formed on the substrate.

3. The material of claim 2, wherein the coating is a zinc phosphate coating.

4. The material described in claim 1 or 2, wherein the nanodiamond particles have a positive zeta potential.

5. The material according to claim 1 or 2, having at least one effect selected from the group consisting of an antiviral effect, an antibacterial effect, and an antifungal effect.

6. A filter with a material, comprising the material according to claim 1 or 2 attached to the filter.

7. A filter with the material according to claim 6, which is used in a gas phase.

8. A nanodiamond particle dispersion liquid used in the preparation of the material described in claim 1 or 2, the nanodiamond particle dispersion liquid containing the nanodiamond particles and a solvent in which the nanodiamond particles are dispersed, the solvent containing at least water, and the concentration of the nanodiamond particles contained in the nanodiamond particle dispersion liquid being 0.01 to 10 mass %.

9. At least one product selected from the group consisting of a coating liquid, a plating liquid, and a chemical conversion treatment liquid, comprising the nanodiamond particle dispersion liquid according to claim 8.

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