Antiviral coating film, method for manufacturing an antiviral coating film, and coated article

Abstract

An antiviral coating film (11) is formed on a surface of a substrate (10) and comprises a plurality of plate-like inorganic particles (20) and a binder resin (30) for aggregating the plurality of plate-like inorganic particles (20). The amount of the plurality of plate-like inorganic particles (20) is 200-2000 vol% inclusive relative to the content of the binder resin (30). The thickness of the antiviral coating film (11) is 1-100 μm inclusive. The average primary particle diameter of the plurality of plate-like inorganic particles (20) is 1-50 μm inclusive. The average thickness of the plurality of plate-like inorganic particles (20) is 5-50 nm inclusive.

Description

Technical Field

[0001] The present disclosure relates to an antiviral coating film formed on the surface of a substrate, a method for manufacturing the antiviral coating film, and a coated article.

Background Art

[0002] In recent years, so-called "pandemics" in which infectious diseases mediated by various microorganisms as pathogens spread rapidly in a short time have become a problem, and deaths due to infections by viruses such as the coronavirus, norovirus, and avian influenza have also been reported.

[0003] Therefore, the development of antiviral agents that exhibit antiviral activity against various viruses has been actively carried out. In fact, resins containing antiviral agents composed of metals such as silver or organic compounds having antiviral activity are applied to various members, and members containing materials carrying antiviral agents are manufactured.

[0004] Patent Document 1 discloses an antimicrobial member in which a cured binder containing an antimicrobial component is fixed to the surface of a substrate, and the arithmetic mean roughness of the surface of the substrate containing the cured binder conforms to JIS (Japanese Industrial Standards) B 0601 and is greater than 4 μm and 50 μm or less.

[0005] In recent years, techniques for imparting antiviral properties by utilizing the uneven structure of the surface of a member without using an antiviral agent have also been reported.

[0006] Patent Document 2 discloses an antiviral surface treatment method for a member that imparts an antiviral action to the surface of the member by randomly forming innumerable minute irregularities on the surface of the member by using the shot blast method, where the minimum value of the uneven pitch is 0.3 μm or more and the maximum value is 1.0 μm or less, and the minimum value of the depth of the recesses is 0.01 μm or more and the maximum value is 0.3 μm or less.

Prior Art Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-50236 [Patent Document 2] Japanese Patent Publication No. 2022-28394 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The virus inactivation technology using antiviral agents described in Patent Document 1 has several drawbacks, including the potential for the emergence of drug-resistant mutant viruses and adverse effects on the human body. Furthermore, depending on the type of antiviral agent, the high cost may limit its applications, creating cost-related challenges.

[0009] The surface treatment method disclosed in Patent Document 2 is a useful surface treatment technique for components that can have an uneven surface shape created by shot blasting. However, depending on the shape of the component, it may be difficult to apply the shot blasting method, and it may be difficult to uniformly form the desired uneven surface shape. Furthermore, if the component is made of a material that can be plastically deformed, such as resin or metal, it is considered possible to create an uneven surface by shot blasting. However, if the component is made of a material that deforms elastically rather than plastically, such as rubber, it is difficult to create an uneven surface even if the shot blasting method is applied.

[0010] This disclosure has been made in view of the above, and aims to obtain an antiviral coating film that can impart antiviral properties to the surface of various components without containing an antiviral agent. [Means for solving the problem]

[0011] To solve the above-mentioned problems and achieve the objective, the antiviral coating film according to this disclosure is an antiviral coating film formed on the surface of a substrate, comprising a plurality of plate-shaped inorganic particles and a binder resin for agglomerating the plurality of plate-shaped inorganic particles. The amount of the plurality of plate-shaped inorganic particles is 200% to 2000% by volume relative to the binder resin content. The thickness of the antiviral coating film is 1 μm to 100 μm. The average primary particle diameter of the plurality of plate-shaped inorganic particles is 1 μm to 50 μm. The average thickness of the plurality of plate-shaped inorganic particles is 5 nm to 50 nm. The arithmetic mean roughness of the surface of the antiviral coating film is between 0.5 μm and 10 μm. The average spacing between adjacent protrusions on the surface is between 20 nm and 1 μm. [Effects of the Invention]

[0012] The antiviral coating film described herein has the effect of imparting antiviral properties to the surfaces of various materials without containing an antiviral agent. [Brief explanation of the drawing]

[0013] [Figure 1] Cross-sectional view of the antiviral member according to Embodiment 1 [Figure 2] Cross-sectional view showing the spacing of protrusions on the surface of the antiviral coating film according to Embodiment 1. [Figure 3] Cross-sectional view of the antiviral member according to Embodiment 2 [Modes for carrying out the invention]

[0014] The antiviral coating film, the method for manufacturing the antiviral coating film, and the coated article according to the embodiment will be described in detail below with reference to the drawings.

[0015] Embodiment 1. Figure 1 is a cross-sectional view of the antiviral member 1 according to Embodiment 1. Figure 1 schematically shows a cross-section of the antiviral member 1. The antiviral member 1 has a base material 10 and an antiviral coating film 11 located on the surface of the base material 10. Figure 1 schematically shows a cross-section of the antiviral coating film 11. As shown in Figure 1, the antiviral coating film 11 is formed on the surface of the base material 10. For example, the base material 10 is made of polystyrene. The antiviral coating film 11 has a plurality of plate-shaped inorganic particles 20 and a binder resin 30 for agglomerating the plurality of plate-shaped inorganic particles 20. For example, each of the plurality of plate-shaped inorganic particles 20 is a calcium silicate particle, and the binder resin 30 is a hydrophilic resin.

[0016] The amount of multiple plate-shaped inorganic particles 20 is between 200% and 2000% by volume relative to the content of the binder resin 30. The thickness of the antiviral coating film 11 is between 1 μm and 100 μm. The average primary particle diameter of the multiple plate-shaped inorganic particles 20 is between 1 μm and 50 μm. In this application, "average primary particle diameter" refers to the average particle size measured by the light scattering method. The average thickness of the multiple plate-shaped inorganic particles 20 is between 5 nm and 50 nm.

[0017] An antiviral member 1 can be formed by applying a coating composition obtained by dissolving and dispersing multiple plate-shaped inorganic particles 20 and a binder resin 30 in water or a solvent to the surface of a substrate 10, and then drying the applied coating composition and the substrate 10.

[0018] The binder resin 30 used in the antiviral coating film 11 and the coating composition is preferably a solvent-soluble resin or a water-dispersible resin. When conducting the antiviral evaluation of the antiviral coating film based on ISO (International Organization for Standardization) 21702, a test virus solution is inoculated onto the surface of the test piece, and in order to prevent the drying of the test virus solution, the test is conducted with a resin film covering it, and the change in the virus concentration is evaluated. At this time, if the water resistance of the binder resin used in the antiviral coating film is poor, dissolution, swelling or peeling of the binder resin may occur during the antiviral evaluation test. Therefore, a water-soluble resin is not preferable as the binder resin 30. However, this is not the case when a reactive compound such as a cross-linking agent is added to the water-soluble resin to make it water-insoluble after the coating film is formed. Also, if the binder resin 30 is a solvent-soluble resin or a water-dispersible resin, an acrylic resin, a urethane resin, a fluorine resin, a silicone resin, or the like can be used as the binder resin 30. Furthermore, a plurality of these resins may be used to form the binder resin 30.

[0019] As the solvent-soluble resin or water-dispersible resin used for the antiviral coating film 11 and the binder resin 30 contained in the coating composition, for example, resins with the trade names of "DAOTAN VTW 1265", "DAOTAN TW 6450", "VIACRYL VSC 6254w", "VIACRYL VSC 6286w" manufactured by Daicel Ornex Co., Ltd., resins with the trade names of "Nitgo polyester WR-901", "Nitgo polyester WR-905" manufactured by Mitsubishi Chemical Corporation, resins with the trade name of "Sampleen H600" manufactured by Sanyo Chemical Industries, Ltd., resins with the trade names of "Lumiflon FE4300", "Lumiflon LF200", or "Lumiflon LF800" manufactured by AGC (Asahi Glass Co., Ltd.) can be used.

[0020] Since the dispersion stability may be impaired by water-soluble impurity components contained in the plate-like inorganic particles 20, as the binder resin 30, a water-dispersible resin with a high resin acid value is preferred, and among them, a water-dispersible resin having an acid value of 30 mgKOH / g or more is preferred. As the preferred water-dispersible resin, for example, resins with the trade names of "Nitgo polyester WR-961", "Nitgo polyester W-1031" manufactured by Mitsubishi Chemical Corporation, or resins with the trade name of "SETAQUA 6302" manufactured by Daicel Ornex Co., Ltd. can be used.

[0021] In addition, in order to improve hydrophilicity, the surface of the antiviral coating film 11 may be surface-treated. Examples of the surface treatment include introduction of hydroxyl groups (-OH) and amino groups (-NH2) to the resin surface using reactive agents such as silane coupling agents, or formation of polymer brushes by surface graft treatment or the like.

[0022] As the material for the plate-shaped inorganic particles 20 used in the antiviral coating film 11, smectite, tobermorite, bentonite, kaolin, mica, boehmite, aluminum, alumina, silica, calcium silicate, calcium carbonate, silicate minerals, boron nitride, graphene, titanium dioxide, hydroxide compounds, carbonate compounds, phosphate compounds, silicate compounds, titanate compounds, etc. can be used. Examples of plate-shaped inorganic particles 20 include particles manufactured by Nippon Insulation Co., Ltd. under the product name "Tobermorite TJ", particles manufactured by Kawai Lime Industry Co., Ltd. under the product name "Cerasure BMF", particles manufactured by Kawai Lime Industry Co., Ltd. under the product name "Cerasure BMM", particles manufactured by Kawai Lime Industry Co., Ltd. under the product name "Cerasure BMT", particles manufactured by AGC SI Tech Co., Ltd. under the product name "Sun Lovely", particles manufactured by Otsuka Chemical Co., Ltd. under the product name "Terraces", particles manufactured by Toyo Aluminum Co., Ltd. under the product name "Aluminum Paste", and particles manufactured by Kinsei Matec Co., Ltd. under the product name "Seraph". Particles, particles manufactured by Nippon Sheet Glass Co., Ltd. under the product name "Silky Flake", particles manufactured by Nippon Sheet Glass Co., Ltd. under the product name "Glass Flake", particles manufactured by Coop Chemical Co., Ltd. under the product name "Micromica", particles manufactured by Coop Chemical Co., Ltd. under the product name "Somasif", particles manufactured by Coop Chemical Co., Ltd. under the product name "Lucentite", particles manufactured by Showa Denko Co., Ltd. under the product name "SBN", particles manufactured by Denki Kagaku Kogyo Co., Ltd. under the product name "Denka Boron Nitride", particles manufactured by New Lime Co., Ltd. under the product name "PS35-A", or particles manufactured by New Lime Co., Ltd. under the product name "PS15-A", etc. can be used.

[0023] Among the various materials mentioned above, tobermorite, a type of calcium silicate hydrate, is a component of lightweight aerated concrete. In lightweight aerated concrete, it exhibits a microstructure in which plate-like crystals overlap each other, forming a card-house structure. When tobermorite is used as plate-like inorganic particles 20, specifically particles of tobermorite manufactured by Nippon Insulation Co., Ltd. under the trade name "Tobermorite TJ," it becomes easier to form the desired uneven surface structure on the antiviral coating film 11. Furthermore, tobermorite has excellent chemical stability, which can suppress the occurrence of corrosion and other issues in the substrate 10 to which the coating composition is applied.

[0024] The substrate 10 used to form the antiviral coating film 11 is not particularly limited and can be appropriately selected according to the type of product in which the antiviral component 1 is used. Examples of the substrate 10 include metal substrates such as aluminum or stainless steel substrates, glass substrates, plastic substrates, or ceramic substrates.

[0025] Figure 2 is a cross-sectional view showing the spacing of protrusions on the surface of the antiviral coating film 11 according to Embodiment 1. Figure 2 schematically shows the cross-section of the antiviral coating film 11. It can also be said that Figure 2 schematically shows the cross-section of the antiviral member 1. The spacing between adjacent protrusions among the irregularities on the surface of the antiviral coating film 11 corresponds to the number of protrusions, D1, D2, ..., D X This is how it is expressed. The average interval is the average distance between all the convex parts.

[0026] It is preferable that the arithmetic mean roughness of the surface of the antiviral coating film 11 is 0.5 μm or more and 10 μm or less, and the average spacing is 20 nm or more and 1 μm or less. If the arithmetic mean roughness is less than 0.5 μm, the antiviral coating film 11 is more susceptible to surface contamination by materials other than viruses, which is undesirable. If the arithmetic mean roughness is greater than 10 μm, virus particles are more likely to adhere to the surface of the plate-like inorganic particles 20, which is undesirable. If the average spacing is less than 20 nm, the average spacing is too small for the virus particles, which is undesirable. If the average spacing is greater than 1 μm, the average spacing is too large for the virus particles, and virus particles adhere to the gaps in the protrusions, which is undesirable.

[0027] As a method for measuring the arithmetic mean roughness on the surface of the antiviral coating film 11, a surface roughness measurement method conforming to JIS B 0601 can be used. Among the various surface roughness measurement methods, a measurement method using a laser microscope or electron microscope that enables non-contact measurement is preferred as a method for measuring arithmetic mean roughness. On the other hand, methods using a stylus-type surface roughness measuring instrument or an atomic force microscope are not preferred as methods for measuring arithmetic mean roughness because, depending on the strength of the antiviral coating film 11, they may cause damage to the surface of the antiviral coating film 11.

[0028] In the method for measuring the spacing between adjacent protrusions on the surface of the antiviral coating film 11, a laser microscope, electron microscope, or atomic force microscope can be used, depending on the size or aggregation state of the plate-shaped inorganic particles 20.

[0029] Embodiment 2. Figure 3 is a cross-sectional view of the antiviral member 2 according to Embodiment 2. Figure 3 schematically shows a cross-section of the antiviral member 2. The antiviral member 2 has a base material 10 and an antiviral coating film 12 provided on the surface of the base material 10. Figure 3 schematically shows a cross-section of the antiviral coating film 12. The antiviral coating film 12 has a plurality of plate-shaped inorganic particles 20 and a binder resin 30 for agglomerating the plurality of plate-shaped inorganic particles 20, similar to the antiviral coating film 11 according to Embodiment 1. The antiviral coating film 12 further has a plurality of hydrophilic inorganic fine particles 40.

[0030] Some of the multiple hydrophilic inorganic fine particles 40 are present on the surface of the antiviral coating film 12, and the remainder of the multiple hydrophilic inorganic fine particles 40 are present inside the antiviral coating film 12. The amount of the multiple hydrophilic inorganic fine particles 40 is between 25% and 500% by volume relative to the content of the binder resin 30. The average primary particle diameter of the multiple hydrophilic inorganic fine particles 40 is 100 nm or less. The water contact angle of each of the multiple hydrophilic inorganic fine particles 40 on the surface of the antiviral coating film 12 is less than 90 degrees.

[0031] When evaluating the antiviral properties of the antiviral coating film 12 in accordance with ISO 21702, the test virus solution is inoculated onto the surface of the test piece, and the test is conducted with a resin film covering it to prevent the test virus solution from drying out, and the change in virus concentration is evaluated. In this case, if the surface of the antiviral coating film is water-repellent, the test virus solution may not sufficiently wet and spread across the surface of the antiviral coating film, and therefore the test virus solution may not adhere to the uneven surface structure of the antiviral coating film, and consequently, an appropriate antiviral evaluation may not be obtained.

[0032] To suppress the adverse effects on antiviral evaluation due to insufficient wettability of such test virus solutions, it is preferable to improve the hydrophilicity of the surface of the antiviral coating film. To improve the hydrophilicity of the surface of the antiviral coating film 12, a plurality of hydrophilic inorganic fine particles 40 are incorporated into the antiviral coating film 12.

[0033] The hydrophilic inorganic fine particles 40 used in the antiviral coating film 12 are not particularly limited, and those known in the art can be used. Examples of hydrophilic inorganic fine particles 40 include silica fine particles, titania fine particles, alumina fine particles, etc. These can be used individually or in combination of two or more. Among these, silica fine particles are preferred because they have silanol groups on their surface and are highly hydrophilic. Furthermore, since silica fine particles are slightly soluble in water, even if contaminants are adsorbed onto the surface of the silica fine particles, the surface layer gradually dissolves upon contact with water, exposing a new surface free of adsorbed contaminants. Therefore, by using silica fine particles, it is possible to maintain hydrophilicity over a long period of time.

[0034] The average particle size of the hydrophilic inorganic fine particles 40 is not particularly limited, but is preferably 4 nm to 100 nm, and more preferably 4 nm to 15 nm. As stated above, in this application, "average primary particle diameter" means the average particle size measured by the light scattering method. By using hydrophilic inorganic fine particles 40 having an average particle size within the above range, the hydrophilicity of the antiviral coating film 12 can be improved without smoothing the uneven structure formed by the plate-like inorganic particles 20 contained in the antiviral coating film 12. However, if the average particle size of the hydrophilic inorganic fine particles 40 is less than 4 nm, it is undesirable because it becomes difficult to maintain hydrophilicity over a long period of time due to the elution of the hydrophilic inorganic fine particles.

[0035] In particular, for silica microparticles having an average particle size within the above range, approximately 15% to 30% by mass of each silica microparticle's surface portion is dissolved in the coating composition. As a result, these silica microparticles also act as a binder when drying the coating composition, thereby increasing the strength of the antiviral coating film 12.

[0036] The amount of hydrophilic inorganic fine particles 40 in the antiviral coating film 12 is preferably 25% to 500% by volume relative to the amount of binder resin 30. If the amount of hydrophilic inorganic fine particles 40 is less than 25% by volume relative to the amount of binder resin 30, the effect of improving the hydrophilicity of the formed antiviral coating film 12 is poor, and sufficient hydrophilicity may not be ensured. Furthermore, if the amount of hydrophilic inorganic fine particles 40 is greater than 500% by volume relative to the amount of binder resin 30, the volume of hydrophilic inorganic fine particles 40 covering the uneven surface structure formed by the plate-like inorganic particles 20 increases, which may reduce the surface roughness of the uneven structure on the surface of the antiviral coating film 12 and potentially decrease its antiviral properties, so this is undesirable.

[0037] Embodiment 3. Next, a method for manufacturing an antiviral coating film according to the embodiment will be described. When manufacturing an antiviral coating film, first a coating composition is manufactured. The coating composition used when manufacturing the antiviral coating film 11 according to Embodiment 1 is manufactured by mixing a binder resin 30, a plurality of plate-shaped inorganic particles 20, and water or a solvent which is a diluent. For example, the binder resin 30 is a hydrophilic resin. Next, the manufactured coating composition is applied to the surface of a substrate 10, and then the applied coating composition and the substrate 10 are dried. This makes it possible to manufacture the antiviral coating film 11 according to Embodiment 1.

[0038] When creating a coating composition, plate-like inorganic particles 20 can be used, which are secondary particles formed by the aggregation of multiple plate-like inorganic fine particles. In this case, a structure in which plate-like inorganic fine particles are stacked on top of each other can be easily formed.

[0039] Multiple hydrophilic inorganic fine particles 40 can be incorporated into the coating composition. When multiple hydrophilic inorganic fine particles 40 are incorporated into the coating composition, the coating composition can be manufactured by mixing multiple hydrophilic inorganic fine particles 40, which are colloidally dispersed in water, with a coating composition consisting of a binder resin 30, multiple plate-shaped inorganic particles 20, and water or a solvent as a diluent. For example, the hydrophilic inorganic fine particles 40 are water-dispersible hydrophilic inorganic fine particles such as colloidal silica. For example, the binder resin 30 is a hydrophilic resin. Next, this coating composition is applied to the surface of the substrate 10, and then the applied coating composition and the substrate 10 are dried. This makes it possible to manufacture the antiviral coating film 12 according to Embodiment 2.

[0040] The hydrophilic inorganic fine particles 40 are not particularly limited, but from the viewpoint of ease of handling, colloidal hydrophilic inorganic fine particles are preferred. Colloidal hydrophilic inorganic fine particles are commercially available. Examples of colloidal hydrophilic inorganic fine particles include particles manufactured by Nissan Chemical Industries, Ltd., with the product name "Snowtex S", particles manufactured by Nissan Chemical Industries, Ltd., with the product name "Snowtex OS", particles manufactured by Nissan Chemical Industries, Ltd., with the product name "Snowtex UP", particles manufactured by Nissan Chemical Industries, Ltd., with the product name "Snowtex ST-30", particles manufactured by Nissan Chemical Industries, Ltd., with the product name "Snowtex OUP", particles manufactured by JGC Catalysts & Chemicals Co., Ltd., with the product name "Cataloid SI-50", or particles manufactured by JGC Catalysts & Chemicals Co., Ltd., with the product name "Cataloid SI-550", etc.

[0041] By applying a coated article having the antiviral coating films 11 and 12 according to Embodiments 1 and 2 to an air conditioning unit such as an indoor unit of an air conditioner or a total heat exchange type ventilation fan, an antiviral effect can be imparted to the air conditioning equipment. [Examples]

[0042] The present disclosure will be specifically explained below with reference to examples. The present disclosure is not limited in any way by the examples. Comparative examples are also shown below. The evaluation members for each example and comparative example were measured and evaluated using the methods described below.

[0043] Example 1. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50%, and plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm were used. 5.3 parts by mass of the binder resin and 2.8 parts by mass of the plate-shaped inorganic particles were added to 91.5 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 969 volume%.

[0044] Example 2. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50%, and plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm were used. 7.7 parts by mass of the binder resin and 2.7 parts by mass of the plate-shaped inorganic particles were added to 89.6 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 646 volume%.

[0045] Example 3. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50% and plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm were used. 2.7 parts by mass of the binder resin and 2.8 parts by mass of the plate-shaped inorganic particles were added to 94.5 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 1938 volume%.

[0046] Example 4. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50%, and plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm were used. 20.9 parts by mass of the binder resin and 2.3 parts by mass of the plate-shaped inorganic particles were added to 76.8 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 204 volume%.

[0047] Example 5. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50% by mass, plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm, and hydrophilic inorganic fine particles with the trade name "Snowtex ST-30" and a solid content of 30% by mass were used. 5.1 parts by mass of the binder resin, 2.7 parts by mass of the plate-shaped inorganic particles, and 2.6 parts by mass of the hydrophilic inorganic fine particles were added to 89.6 parts by mass of ion-exchanged water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 969% by volume, and the amount of hydrophilic inorganic fine particles relative to the binder resin was 57% by volume.

[0048] Example 6. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50% by mass, plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm, and hydrophilic inorganic fine particles with the trade name "Snowtex ST-30" and a solid content of 30% by mass were used. 4.6 parts by mass of the binder resin, 2.4 parts by mass of the plate-shaped inorganic particles, and 11.6 parts by mass of the hydrophilic inorganic fine particles were added to 81.3 parts by mass of ion-exchanged water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 969% by volume, and the amount of hydrophilic inorganic fine particles relative to the binder resin was 286% by volume.

[0049] Example 7. A binder resin with the product name "SETAQUA 6302" and a solid content of 50% by mass, plate-shaped inorganic particles with the product name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm, and hydrophilic inorganic fine particles with the product name "Snowtex ST-30" and a solid content of 30% by mass were used. 15.1 parts by mass of the binder resin, 2.4 parts by mass of the plate-shaped inorganic particles, and 10.5 parts by mass of the hydrophilic inorganic fine particles were added to 73.5 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 294% by volume, and the amount of hydrophilic inorganic fine particles relative to the binder resin was 17% by volume.

[0050] Comparative Example 1. The polystyrene substrate used in the example was designated as Comparative Example 1.

[0051] Comparative Example 2. A coating composition was obtained by adding 5.0 parts by mass of a binder resin, whose trade name is "SETAQUA 6302" and has a solid content of 50%, to 95.0 parts by mass of deionized water. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film.

[0052] Comparative Example 3. A coating composition was obtained by adding 5.0 parts by mass of plate-shaped inorganic particles, whose trade name is "Tobermorite TJ," with an average primary particle diameter of 1 μm and an average thickness of 20 nm, to 95.0 parts by mass of ethanol. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film.

[0053] Comparative Example 4. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50%, and plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm were used. 2.6 parts by mass of the binder resin and 5.5 parts by mass of the plate-shaped inorganic particles were added to 91.9 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 3905 volume%.

[0054] Comparative Example 5. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50%, and plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm were used. 5.1 parts by mass of the binder resin and 6.6 parts by mass of the plate-shaped inorganic particles were added to 88.4 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to prepare an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 2389 volume%.

[0055] Comparative Example 6. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50% and plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm were used. 25.0 parts by mass of the binder resin and 2.2 parts by mass of the plate-shaped inorganic particles were added to 72.8 parts by mass of deionized water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 162 volume%.

[0056] Comparative Example 7. A binder resin with the trade name "SETAQUA 6302" and a solid content of 50% by mass, plate-shaped inorganic particles with the trade name "Tobermorite TJ" and an average primary particle diameter of 1 μm and an average thickness of 20 nm, and hydrophilic inorganic fine particles with the trade name "Snowtex ST-30" and a solid content of 30% by mass were used. 2.4 parts by mass of the binder resin, 2.5 parts by mass of the plate-shaped inorganic particles, and 11.9 parts by mass of the hydrophilic inorganic fine particles were added to 83.2 parts by mass of ion-exchanged water to obtain a coating composition. The obtained coating composition was applied to the surface of a substrate made of polystyrene, and then the applied coating composition and the substrate were dried to produce an evaluation member having a coating film. In the coating film obtained at this time, the amount of plate-shaped inorganic particles relative to the binder resin was 1938 volume%, and the amount of hydrophilic inorganic fine particles relative to the binder resin was 571 volume%.

[0057] The following describes each evaluation method.

[0058] Measurement of surface roughness For each evaluation member obtained in Examples 1 to 7 and Comparative Examples 1 to 7, an Olympus laser microscope, product name OLS4100, was used as a non-contact surface roughness measuring instrument. The arithmetic mean roughness was measured at 10 points over a measurement length of 1 mm in accordance with JIS B 0601, and the average value was taken as the measurement result for the arithmetic mean roughness. The measurement results are shown in Table 1 below.

[0059] Antiviral evaluation To evaluate the antiviral properties, the virus inactivation rate was measured as follows. "Antiviral properties" refer to the property of reducing the number of viruses attached to the surface of the coating. The antiviral tests were conducted as follows. To evaluate the antiviral properties of each evaluation material obtained in Examples 1 to 7 and Comparative Examples 1 to 7, ISO 21702, a method modified from JIS Z2801, was used. In the measurement results, for each evaluation material obtained in Examples 1 to 7 and Comparative Examples 1 to 7, the feline calicivirus concentration that has lost its ability to infect CRFK (Crandell-Rees Feline Kidney) cells is expressed as feline calicivirus inactivity, based on Annex B of JIS L1922. Here, as an indicator of virus concentration, the virus inactivity, which is the concentration of virus that has been inactivated against CRFK cells, was used, and the antiviral activity value was calculated based on this virus inactivity. The measurement results are shown in Table 1 below.

[0060] The procedure for calculating antiviral activity values ​​is described below. (1) Drop 0.4 mL of virus solution onto a 5 cm square test piece and cover it with a 4 cm square film. The test pieces include both antiviral treated and untreated samples. (2) Leave the test specimen undisturbed at 25°C for 24 hours. (3) After standing, the virus on the test piece is washed off and collected, and then the viral infectivity titer is measured. (4) The antiviral activity value is calculated using the following formula. R = Ut - At R: Antiviral activity value Ut: Mean of the common logarithm of the viral infectivity titer after 24 hours of standing in unprocessed samples. At: The average of the common logarithms of the viral infectivity titer after 24 hours of standing in antiviral-treated products. The unit of viral infectivity titer is PFU / cm². 2 That is the case.

[0061] The antiviral activity was evaluated based on the following evaluation criteria. G: Those showing an antiviral activity value of 2.0 or higher. P: Those showing an antiviral activity value of less than 2.0

[0062] Evaluation of hydrophilicity To evaluate the hydrophilicity of the coating film surface, the initial water droplet contact angle was measured as follows. The "water contact angle" indicates the degree of affinity between the material surface and water; a smaller water contact angle indicates higher hydrophilicity, while a larger water contact angle indicates lower hydrophilicity. Generally, a water contact angle of 90 degrees or less indicates hydrophilicity, and a water contact angle greater than 90 degrees indicates hydrophobicity.

[0063] Using a DM301 contact angle meter manufactured by Kyowa Interface Science, a 2 μL water droplet was dropped onto the coating film in air at approximately 25°C, and the static contact angle of the water droplet was measured. Hydrophilicity was evaluated based on the evaluation criteria described below. The measurement results are shown in Table 1 below. E: Those that exhibit a contact angle with water of 30 degrees or less, which is the standard for hydrophilicity. G: Those whose contact angle with water, which is the standard for hydrophilicity, is greater than 30 degrees and less than or equal to 90 degrees. P: Those exhibiting a contact angle with water greater than 90 degrees, which is the standard for hydrophobicity. Furthermore, during the measurement of the water contact angle, if the coating peeled off due to contact with water droplets, it was considered to lack water resistance, and the water contact angle measurement was not performed.

[0064] [Table 1]

[0065] Evaluation results From the evaluation results for Examples 1 to 7 and Comparative Examples 1 to 7 shown in Table 1, an antiviral coating film exhibiting antiviral properties can be obtained when the content of plate-like inorganic particles in the binder resin is 200% to 2000% by volume, the arithmetic mean roughness on the surface of the coating film is 0.5 μm to 10 μm, and the average spacing between adjacent protrusions is 20 nm to 1 μm.

[0066] When the content of plate-like inorganic particles relative to the binder resin exceeded 2000 volume%, the water resistance of the coating film was poor, making antiviral evaluation impossible.

[0067] When the content of plate-shaped inorganic particles relative to the binder resin is less than 200% by volume, water resistance of the coating film is obtained, but it was confirmed that the antiviral activity value decreases because the irregularities on the surface of the coating film are flattened by the binder resin.

[0068] We were able to confirm that the antiviral activity value is further improved when hydrophilic inorganic fine particles are included in an amount of 25% to 500% by volume relative to the binder resin content, with an average primary particle diameter of 100 nm or less, and the water contact angle is less than 30 degrees.

[0069] As shown in Comparative Example 7, it was confirmed that the antiviral activity value decreases when the content of hydrophilic inorganic fine particles with an average primary particle diameter of 100 nm or less exceeds 500 volume% relative to the binder resin content.

[0070] As described above, the antiviral coating films 11 and 12 according to Embodiments 1 and 2 are antiviral coating films formed on the surface of a substrate 10, and have a plurality of plate-shaped inorganic particles 20 and a binder resin 30 for agglomerating the plurality of plate-shaped inorganic particles 20. The amount of the plurality of plate-shaped inorganic particles 20 is 200% to 2000% by volume relative to the content of the binder resin 30. The thickness of the antiviral coating films 11 and 12 is 1 μm to 100 μm. The average primary particle diameter of the plurality of plate-shaped inorganic particles 20 is 1 μm to 50 μm. The average thickness of the plurality of plate-shaped inorganic particles 20 is 5 nm to 50 nm. The antiviral coating films 11 and 12 become stable coating films by containing the binder resin 30 and the plurality of plate-shaped inorganic particles 20 in the predetermined volume ratio described above. Since the antiviral coating films 11 and 12 have plate-shaped inorganic particles having the above average primary particle diameter and thickness, they can exhibit antiviral properties.

[0071] For example, the binder resin 30 is a hydrophilic resin. When the binder resin 30 is a hydrophilic resin, the hydrophilicity of the surface of the antiviral coating films 11 and 12 is improved, the affinity between the virus solution and the surface during antiviral testing is improved, and the antiviral coating films 11 and 12 can exhibit higher antiviral activity.

[0072] For example, the arithmetic mean roughness of the surface of the antiviral coating films 11 and 12 is 0.5 μm or more and 10 μm or less, and the average spacing between adjacent protrusions on the surface is 20 nm or more and 1 μm or less. In this case, the antiviral coating films 11 and 12 can improve their virus inactivation effect due to the uneven surface shape.

[0073] The antiviral coating film 12 further comprises a plurality of hydrophilic inorganic fine particles 40 in an amount of 25% to 500% by volume relative to the content of the binder resin 30. The average primary particle diameter of the plurality of hydrophilic inorganic fine particles 40 is 100 nm or less. Preferably, the water contact angle of the hydrophilic inorganic fine particles 40 located on the surface of the antiviral coating film 12 is less than 30 degrees. Because the antiviral coating film 12 contains hydrophilic inorganic fine particles 40, the hydrophilicity of the surface of the antiviral coating film 12 is improved. When the water contact angle is less than 30 degrees, the affinity of the surface of the antiviral coating film 12 with water droplets is high, the affinity of the virus solution with the surface is improved, and the antiviral coating film 12 can exhibit higher antiviral properties.

[0074] For example, a method for manufacturing an antiviral coating film includes the steps of applying a coating composition containing a plurality of plate-shaped inorganic particles 20, a binder resin 30, a plurality of hydrophilic inorganic fine particles 40, and water to the surface of a substrate 10, and drying the coating composition applied to the surface of the substrate 10. Each of the plurality of plate-shaped inorganic particles 20 is a secondary particle formed by the aggregation of a plurality of plate-shaped inorganic fine particles. Since the coating composition contains plate-shaped inorganic fine particles, which are secondary particles, irregularities derived from the secondary particles are more easily formed on the surface of the antiviral coating film after the coating composition has been applied and dried. Compared to a case where the coating composition does not contain secondary particles, when the coating composition contains secondary particles, it is easier to form irregularities on the surface of the antiviral coating film.

[0075] For example, the antiviral coating films 11 and 12 are provided on a coated article. For example, the antiviral coating films 11 and 12 are provided on the surface of a coated article. A coated article provided with the antiviral coating films 11 and 12 can exhibit antiviral properties.

[0076] The configurations shown in the above embodiments are merely examples and can be combined with other known technologies, and parts of the configuration can be omitted or modified without departing from the gist of the invention. [Explanation of Symbols]

[0077] 1,2 Antiviral component, 10 Substrate, 11,12 Antiviral coating film, 20 Plate-shaped inorganic particles, 30 Binder resin, 40 Hydrophilic inorganic fine particles.

Claims

1. An antiviral coating film formed on the surface of a substrate, Multiple plate-like inorganic particles, The system comprises a binder resin for agglomerating the plurality of plate-shaped inorganic particles, The amount of the plurality of plate-shaped inorganic particles is 200% by volume or more and 2000% by volume or less relative to the content of the binder resin. The thickness of the antiviral coating film is 1 μm or more and 100 μm or less. The average primary particle diameter of the plurality of plate-like inorganic particles is 1 μm or more and 50 μm or less. The average thickness of the plurality of plate-like inorganic particles is 5 nm or more and 50 nm or less. The arithmetic mean roughness of the surface of the antiviral coating film is 0.5 μm or more and 10 μm or less. The average distance between adjacent protrusions on the aforementioned surface is between 20 nm and 1 μm. An antiviral coating film characterized by the following:

2. An antiviral coating film formed on the surface of a substrate, Multiple plate-like inorganic particles, The system comprises a binder resin for agglomerating the plurality of plate-shaped inorganic particles, The amount of the plurality of plate-shaped inorganic particles is 200% by volume or more and 2000% by volume or less relative to the content of the binder resin. The thickness of the antiviral coating film is 1 μm or more and 100 μm or less. The average primary particle diameter of the plurality of plate-like inorganic particles is 1 μm or more and 50 μm or less. The average thickness of the plurality of plate-like inorganic particles is 5 nm or more and 50 nm or less. Each of the aforementioned plurality of plate-shaped inorganic particles is a calcium silicate particle. An antiviral coating film characterized by the following:

3. An antiviral coating film formed on the surface of a substrate, Multiple plate-like inorganic particles, The system comprises a binder resin for agglomerating the plurality of plate-shaped inorganic particles, The amount of the plurality of plate-shaped inorganic particles is 200% by volume or more and 2000% by volume or less relative to the content of the binder resin. The thickness of the antiviral coating film is 1 μm or more and 100 μm or less. The average primary particle diameter of the plurality of plate-like inorganic particles is 1 μm or more and 50 μm or less. The average thickness of the plurality of plate-like inorganic particles is 5 nm or more and 50 nm or less. The binder resin further comprises a plurality of hydrophilic inorganic fine particles in an amount of 25% to 500% by volume relative to its content. The average primary particle diameter of the plurality of hydrophilic inorganic fine particles is between 4 nm and 100 nm. The water contact angle of the hydrophilic inorganic fine particles located on the surface of the antiviral coating film, among the plurality of hydrophilic inorganic fine particles, is less than 30 degrees. An antiviral coating film characterized by the following:

4. The binder resin is a hydrophilic resin. The antiviral coating film according to any one of claims 1 to 3.

5. The arithmetic mean roughness of the surface of the antiviral coating film is 0.5 μm or more and 10 μm or less. The average distance between adjacent protrusions on the aforementioned surface is between 20 nm and 1 μm. The antiviral coating film according to feature 2 or 3.

6. Each of the plurality of plate-shaped inorganic particles is a calcium silicate particle. The antiviral coating film according to feature 1 or 3.

7. The invention further comprises a plurality of hydrophilic inorganic fine particles in an amount of 25% by volume or more and 500% by volume or less relative to the content of the binder resin, The average primary particle diameter of the plurality of hydrophilic inorganic fine particles is between 4 nm and 100 nm. The water contact angle of the hydrophilic inorganic fine particles located on the surface of the antiviral coating film, among the plurality of hydrophilic inorganic fine particles, is less than 30 degrees. The antiviral coating film according to feature 1 or 2.

8. The process involves applying a coating composition containing multiple plate-shaped inorganic particles, which are secondary particles formed by the aggregation of multiple plate-shaped inorganic fine particles, a binder resin, multiple hydrophilic inorganic fine particles, and water to the surface of a substrate. A step of drying the coating composition applied to the surface of the substrate. A method for producing an antiviral coating film, characterized by containing [a certain substance].

9. A coated article characterized by comprising an antiviral coating film according to any one of claims 1 to 3.

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