Aggregated particle, aggregated particle dispersion liquid, and production methods therefor

Abstract

The present invention provides: aggregated particles which exhibit high dispersibility not only under acidic conditions of pH 2 or higher but lower than pH 7 but also under alkaline conditions of pH 7 to pH 9 inclusive; an aggregated particle dispersion liquid; a coating material containing the particles; methods for producing the aggregated particles, the dispersion liquid, and the coating material; and a method for forming an antiviral surface.　The present invention specifically provides: aggregated particles in which silica nanoparticles each having an amino group on the surface thereof or silica nanoparticles each containing an aluminum compound and ceria nanoparticles having a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid adsorbed on the surfaces thereof are aggregated; an aggregated particle dispersion liquid; a coating material containing the particles; methods for producing the aggregated particles, the dispersion liquid, and the coating material; and a method for forming an antiviral surface.

Description

Aggregated particles, aggregated particle dispersion, and method for producing the same

[0001] The present invention relates to aggregate particles, aggregate particle dispersions, methods for producing the same, their applications, and methods for forming antiviral coating surfaces.

[0002] Various antibacterial and antiviral agents have been developed to suppress bacterial growth and virus transmission on the surfaces of products that may come into contact with hands or people, such as building materials and home appliances. Examples of antibacterial and antiviral agents include quaternary ammonium salts, photocatalysts such as titanium dioxide, and metal ions such as silver.

[0003] Cerium oxide possesses oxidizing properties and does not require special light sources such as ultraviolet light. It has the characteristic of exhibiting antiviral properties against various viruses and antibacterial properties against various bacteria through oxidation reactions even in the dark.

[0004] One method for coating the solid surface of a product with such antibacterial and antiviral agents is to mix the antibacterial and antiviral agent with a binder resin such as acrylic resin and apply the mixture to the surface as a coating.

[0005] Here, Patent Document 1 describes that by using cerium oxide nanoparticles or a dispersion containing said nanoparticles, which are produced by adding an oxidizing agent to a solution containing a boron compound and cerium(III) ions, it is possible to oxidize and decompose organic matter and various harmful substances in high yield, and that said nanoparticles or said dispersion can be used as high-performance antiviral and antibacterial agents to inactivate various viruses.

[0006] Patent Document 2 describes that cerium oxide nanoparticles, whose surface is coated with a vinyl polymer or polyamide having a heterocyclic amine skeleton, can decompose nucleic acids and polypeptides at a higher rate than conventional nanoparticles.

[0007] Patent Document 3 describes that by using a dispersion containing cerium oxide nanoparticles produced by mixing a solution of an aromatic heterocyclic compound with a solution containing cerium(III) ions or a cerium(III) salt and adding an oxidizing agent, harmful substances can be oxidized and decomposed in a higher yield than with conventional cerium oxide nanoparticles, and active species can be eliminated in a higher yield than with conventional cerium oxide nanoparticles.

[0008] Patent Document 4 describes that by using a dispersion containing cerium oxide nanoparticles, which is produced by mixing a solution of an alicyclic amine with a solution containing cerium(III) ions or a cerium(III) salt and adding an oxidizing agent, harmful substances can be oxidized and decomposed in a higher yield than with conventional cerium oxide nanoparticles, and active species can be eliminated in a higher yield than with conventional cerium oxide nanoparticles.

[0009] International Publication No. 2021 / 241490, International Publication No. 2020 / 129963, International Publication No. 2021 / 132628, International Publication No. 2021 / 132643

[0010] The inventors investigated the preparation of a paint by mixing cerium oxide nanoparticles disclosed in Patent Documents 1 to 4 with a binder resin in order to form a surface with antiviral properties. These cerium oxides exhibited high dispersibility in acidic binder resin solutions with a pH of less than 7, but aggregated in binder resin solutions with a pH between 7 and 9, making it impossible to prepare the paint.

[0011] Based on this, we concluded that the above nanoparticles have the problem of not being able to disperse stably under conditions of pH 7 to pH 9.

[0012] Based on the above, we conducted studies with the aim of obtaining particles and dispersions containing cerium oxide that have high dispersibility in the pH range of pH 2 to pH 9.

[0013] The inventors diligently conducted research to solve the above problems. As a result, they obtained aggregate particles that exhibit high dispersibility not only under acidic conditions of pH 2 to less than pH 7, but also under alkaline conditions of pH 7 to pH 9, by assembling (A) nanoparticles of a metal oxide, wherein the metal oxide has a specific gravity of 7.0 or less, with (B) ceria nanoparticles on which a boron compound, heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on its surface. A paint containing these aggregate particles also exhibited high dispersibility.

[0014] The present invention is as follows:

[0015] (1) An aggregate particle comprising: (A) nanoparticles of a metal oxide, wherein the metal oxide has a specific gravity of 7.0 or less; and (B) ceria nanoparticles on which a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on its surface. (2) The aggregate particle according to (1), wherein the nanoparticles of the metal oxide are nanoparticles of titania, nanoparticles of zirconia, nanoparticles of chromium oxide, nanoparticles of alumina, silica nanoparticles having an amino group on its surface, or silica nanoparticles containing an aluminum compound. (3) The aggregate particle according to (2), wherein the silica nanoparticles having an amino group on its surface are silica nanoparticles in which the oxygen atoms on the surface of the silica nanoparticles are aminoalkylsilylated. (4) The aggregate particle according to (3), wherein the aminoalkyl group is an aminomethyl group, a 2-aminoethyl group, a 3-aminopropyl group, or an aminobutyl group. (5) The aggregate particle according to any one of (1) to (4), wherein the boron compound is a boron compound represented by the following general formula (I). ｎ (OR') ３－ｎ... (I) [(In general formula (I), n is an integer from 0 to 2, R represents an alkyl group having 1 to 4 carbon atoms, a phenyl group or a tolyl group, and R' represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a phenyl group or a tolyl group. If there are multiple R or R', they may be the same or different.] (6) The aggregate particle according to any one of (1) to (5), wherein the heterocyclic amine is a compound having one or more skeletons selected from the group consisting of a pyrazole skeleton, an imidazole skeleton, a triazole skeleton, a pyridine skeleton, a pyridazine skeleton, a pyrimidine skeleton, a pyrazine skeleton, a triazine skeleton, a tetrazine skeleton, an indazole skeleton, a benzimidazole skeleton, an azaindole skeleton, a pyrazolopyrimidine skeleton, a purine skeleton, a benzotriazole skeleton, a quinoxaline skeleton, a sinnoline skeleton, a quinazoline skeleton, a phthalazine skeleton, a naphthyridine skeleton and a pteridine skeleton. (7) A dispersion of aggregate particles in which aggregate particles described in any one of (1) to (6) are dispersed. (8) The dispersion of aggregate particles described in (7) which has antiviral properties. (9) The dispersion of aggregate particles described in (7) or (8) which has antiallergenic properties. (10) A method for producing a dispersion of aggregate particles, comprising the step of mixing a dispersion of nanoparticles of a metal oxide having a specific gravity of 7.0 or less with a dispersion of ceria nanoparticles on which a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on its surface. (11) The method for producing a dispersion of aggregate particles described in (10), wherein the nanoparticles of the metal oxide are nanoparticles of titania, nanoparticles of zirconia, nanoparticles of chromium oxide, nanoparticles of alumina, nanoparticles of silica having an amino group on its surface, or nanoparticles containing an aluminum compound. (12) The manufacturing method according to (10) or (11), wherein the dispersion of ceria nanoparticles is produced by adding an oxidizing agent to a solution containing a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid and a cerium(III) salt. (13) The manufacturing method according to (12), wherein the oxidizing agent is hypochlorous acid, permanganate, chromic acid, dichromate, hydrogen peroxide, oxygen and / or ozone. (14) A paint containing aggregate particles, comprising aggregate particles according to any one of (1) to (6), or a dispersion in which such aggregate particles are dispersed.(15) A method for forming an antiviral surface by applying the aggregate particle dispersion described in (7), or an aggregate particle-containing paint containing the aggregate particle dispersion, to a solid surface. (16) The method for forming the antiviral surface according to (15), wherein the antiviral activity value of the antiviral surface according to ISO 21702 is 2.0 or higher. (17) A method for forming an antiallergenic surface by applying the aggregate particle dispersion described in (7), or an aggregate particle-containing paint containing the aggregate particle dispersion, to a solid surface. (18) The method for forming the antiallergenic surface according to (17), wherein the antiallergenic activity value of the antiallergenic surface, when measured by the following steps 1 to 3, is 70% or higher. Step 1: A supply step in which a test solution containing an allergen is supplied to the surface to be measured on the anti-allergenic surface; Step 2: A reaction step in which a covering film is placed over the surface to be measured on the anti-allergenic surface to which the test solution has been supplied, and the allergen in the test solution is reacted with the anti-allergen agent on the surface to be measured on the anti-allergenic surface while the test solution is spread between the covering film and the surface to be measured; Step 3: A measurement step in which the test solution after the reaction is collected and the anti-allergen activity value is measured by enzyme immunoassay (ELISA).

[0016] The aggregate particles of the present invention, and the aggregate particle dispersion in which these aggregate particles are dispersed, exhibit high dispersibility over a wide pH range of pH 2 to pH 9. Furthermore, the paint containing the aggregate particles of the present invention also exhibits high dispersibility.

[0017] This figure illustrates the structure of a polymer that is one of the heterocyclic amines of the present invention. This figure illustrates the structure of a polymer having a piperazine skeleton, which is one of the heterocyclic amines of the present invention. This is a scanning transmission electron microscope (STEM) image of the aggregated particles obtained in Example 2.

[0018] In this specification, metal oxides with a specific gravity of 7.0 or less are referred to as "metal oxide a".

[0019] 1. Aggregated Particles The aggregated particles of the present invention are aggregated particles comprising (A) nanoparticles of a metal oxide, wherein the metal oxide is a metal oxide with a specific gravity of 7.0 or less, and (B) ceria nanoparticles on which a boron compound, heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on its surface.

[0020] The aggregate particles of this invention are a concept that includes silica ceria particles, as described below.

[0021] In this specification, "aggregation" means that the surfaces of metal oxide a nanoparticles and ceria nanoparticles are attracted to each other by intermolecular forces such as van der Waals forces, polar attractive forces, and hydrogen bonds, causing the particles to come into contact and form aggregated particles that can be dispersed without aggregation in the solvent described below. In the aggregated particles, there may be portions in which metal oxide a nanoparticles or ceria nanoparticles are in contact with each other due to the intermolecular forces. Furthermore, chemical bonds such as covalent bonds, ionic bonds, and metallic bonds may be formed at the contact between the particles. Particles in which one or more metal oxide a nanoparticles are embedded inside one ceria nanoparticle by calcination, or in which one or more ceria nanoparticles are embedded inside one metal oxide a nanoparticle, are not included in the "aggregated" particles as defined in this specification.

[0022] The presence of metal oxide a atoms and cerium atoms with a specific gravity of 7.0 or less in the aggregate particles, as well as the presence of stabilizing agents in ceria nanoparticles, can be measured by XPS. XPS can obtain information about the elements on the surface of the nanoparticles, and metal oxide a, cerium, and various stabilizers with a specific gravity of 7.0 or less can be identified from the peak positions of the obtained spectrum.

[0023] When performing XPS, aggregate particles should be dried with hot air or freeze-dried powder. Alternatively, mass spectrometry can be performed on the aggregate particles and nanoparticles, or on dispersions in a solvent, to directly detect and identify stabilizers on the surfaces of the aggregate particles and nanoparticles.

[0024] Alternatively, strong acids, strong alkalis, oxidizing agents, reducing agents, etc. may be added to dissolve the aggregated particles, and the solution may be mass-analyzed to identify the ions of the stabilizer adsorbed on the metal oxide a or ceria nanoparticles having a specific gravity of 7.0 or less. As long as it is a method for dissolving the aggregated particles, the metal oxide a nanoparticles, and the ceria nanoparticles having a specific gravity of 7.0 or less, the stabilizer can be identified even for particles containing the stabilizer inside. Examples of the mass analysis include inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS).

[0025] The particle size of the aggregated particles can be measured as the hydrodynamic diameter when a dispersion liquid described later is used.

[0026] 2. Silica-ceria particles The silica-ceria particles of the present invention are particles in which silica nanoparticles having an amino group on the surface or silica nanoparticles containing an aluminum compound and ceria nanoparticles having a boron compound and / or heterocyclic amine adsorbed on the surface are aggregated.

[0027] The presence of silicon atoms and cerium atoms in the silica-ceria particles and the presence of the stabilizer component of the ceria nanoparticles can be measured by XPS. XPS can obtain information on the elements in the surface layer of the nanoparticles, and silica, cerium, and various stabilizers can be identified from the peak positions of the obtained spectra.

[0028] 3. Nanoparticles of metal oxide a In the present invention, the metal oxide a is one or more metal oxides selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, beryllium oxide, rubidium oxide, calcium oxide, vanadium oxide, magnesia, alumina, titania, niobium oxide, cesium oxide, molybdenum oxide, strontium oxide, manganese oxide, chromium oxide, iron oxide, zinc oxide, zirconia, barium oxide, copper oxide, cobalt oxide, nickel oxide, tin oxide, silica nanoparticles having an amino group on the surface, and silica nanoparticles containing an aluminum compound. In this specification, the concept of "metal oxide a" does not include ceria.

[0029] The nanoparticles of the metal oxide a of the present invention are preferably nanoparticles of titania, nanoparticles of zirconia, nanoparticles of chromium oxide, nanoparticles of alumina, silica nanoparticles having an amino group on the surface (hereinafter, "aminosilica nanoparticles") or silica nanoparticles containing an aluminum compound (hereinafter, "aluminum-containing silica nanoparticles").

[0030] In the present invention, by aggregating (A) nanoparticles of a metal oxide, wherein the metal oxide is a metal oxide having a specific gravity of 7.0 or less, with (B) ceria nanoparticles, aggregated particles having high dispersibility can be obtained not only under acidic conditions of pH 2 or more and less than pH 7 but also under alkaline conditions of pH 7 or more and pH 9 or less.

[0031] As used herein, the term "specific gravity" means a dimensionless value obtained by comparing the density of a substance with a reference substance, and is defined as the value obtained by dividing the density of the target substance at the same temperature by the reference density, with the density of water at 25°C (1 g / cm ３ ) as the reference. Note that the specific gravity is a value without a unit, and when the temperature conditions are different, the density of water at that temperature shall be used as the reference.

[0032] As used herein, the term "nanoparticle" refers to particles having a particle size of 1 nm or more and 1000 nm or less. Since the particle size of the nanoparticles approximates the hydrodynamic diameter when the nanoparticles are in a dispersion, the nanoparticles of the present invention can also be defined as particles having a hydrodynamic diameter of 1 nm or more and 1000 nm or less when in a dispersion.

[0033] The hydrodynamic diameter of nanoparticles is calculated by measuring dynamic light scattering to derive an autocorrelation function, analyzing it using the Non-Negative Least Squares method (NNLS method), and then calculating the average particle diameter from the number-converted histogram. For dynamic light scattering measurements, Otsuka Electronics Co., Ltd.'s ELSZ-2000ZS is used. Particle diameter can be measured directly from the nanoparticle dispersion; if the particle concentration is high, it may be diluted with water, nitric acid, sodium hydroxide, etc.; if the particle concentration is low, it may be measured after membrane concentration or evaporation. If the nanoparticle dispersion contains compounds that affect the hydrodynamic diameter of the nanoparticles, these should be removed by membrane purification or centrifugation before measurement. If debris is present in addition to nanoparticles, the debris should be removed by centrifugation and the supernatant measured. The nanoparticle dispersion can also be measured after sonication.

[0034] Examples of solvents include water and / or organic solvents. Water is a preferred solvent.

[0035] Metal oxide nanoparticles can be produced as a dispersion. Water and / or a water-compatible solvent are preferred as the solvent, i.e., dispersion medium, used to prepare the dispersion of metal oxide a nanoparticles. Specific examples of water-compatible solvents include: alcohols such as methanol, ethanol, isopropanol, n-butanol, and methylisocarbinol; ketones such as acetone, 2-butanone, ethyl amyl ketone, diacetone alcohol, isophorone, and cyclohexanone; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; ethers such as diethyl ether, isopropyl ether, tetrahydrofuran, 1,4-dioxane, and 3,4-dihydro-2H-pyran; glycol ethers such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, and ethylene glycol dimethyl ether; and 2-meth Organic solvents such as glycol ether acetates including oxyethyl acetate, 2-ethoxyethyl acetate, and 2-butoxyethyl acetate; esters including methyl acetate, ethyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, and ethylene carbonate; aromatic hydrocarbons including benzene, toluene, and xylene; aliphatic hydrocarbons including hexane, heptane, isooctane, and cyclohexane; halogenated hydrocarbons including methylene chloride, 1,2-dichloroethane, dichloropropane, and chlorobenzene; sulfoxides including dimethyl sulfoxide; and pyrrolidones including N-methyl-2-pyrrolidone and N-octyl-2-pyrrolidone can be used.

[0036] 3-1. Aminosilica Nanoparticles The "aminosilica nanoparticles" of the present invention are silica nanoparticles having amino groups on their surface. Preferred aminosilica nanoparticles are nanoparticles in which amino groups are bonded to the surface of silica nanoparticles via chemical bonds. An example of a preferred method for bonding amino groups to the surface of silica nanoparticles via chemical bonds is a method of modifying the surface of silica nanoparticles with (aminoalkyl)trialkoxysilane represented by the following general formula (II).

[0037] R １ -Si(OR ２ ) ３... (II) [In the general formula (II), R １ represents an alkyl group having at least one amino group and having 1 to 6 carbon atoms, and R ２ represents an alkyl group having 1 to 6 carbon atoms.] In the (aminoalkyl) trialkoxysilane represented by the general formula (II), the aminoalkyl group R １ is preferably an alkyl group having 1 to 4 carbon atoms (aminomethyl group, aminoethyl group, aminopropyl group, aminobutyl group), and a linear alkyl group having 1 to 4 carbon atoms having an amino group (aminomethyl group, 2-aminoethyl group, 3-amino-n-propyl group, 4-amino-n-butyl group) is more preferable. The alkyl group R ２ may be linear, branched or cyclic, and is preferably an alkyl group having 1 to 4 carbon atoms (methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, cyclopropyl group or cyclobutyl group). Specific examples of the (aminoalkyl) trialkoxysilane include triethoxy(3-amino-n-propyl)silane, trimethoxy(3-amino-n-propyl)silane, and the like.

[0038] Preferred amino-silica nanoparticles are silica nanoparticles in which an oxygen atom on the surface of the silica nanoparticles forms a covalent bond with a silicon atom derived from (aminoalkyl) trialkoxysilane, and an aminoalkyl group is covalently bonded to the surface of the silica nanoparticles through the silicon atom.

[0039] The shape of the amino-silica nanoparticles is preferably spherical.

[0040] The hydrodynamic diameter of the amino-silica nanoparticles when in a dispersion is preferably 5 nm or more and 80 nm or less, and more preferably 10 nm or more and 60 nm or less.

[0041] The solvent used when making the amino-silica nanoparticles into a dispersion is preferably the solvent used for dispersing the aggregated particles described below in 5.

[0042] When aminosilica nanoparticles are dispersed, their zeta potential in an aqueous solution at pH 7 is preferably between +1 mV and +70 mV, and more preferably between +20 mV and +60 mV.

[0043] The pH of the aminosilica nanoparticles in dispersion is preferably 2.0 to 10.5, and more preferably 3.0 to 6.0.

[0044] The aminosilica nanoparticle dispersion can be a commercially available product, and a specific example is "Silica, nanoparticle dispersion in water" (product name, product number 791342) manufactured by Sigma-Aldrich Japan LLC.

[0045] 3-2. Aluminum-containing silica nanoparticles Aluminum-containing silica nanoparticles are silica nanoparticles in which an aluminum compound is contained on the surface of the silica nanoparticle. Aluminum-containing silica nanoparticles may be particles in which the aluminum compound is bound only to the surface, or particles in which the aluminum compound is contained not only on the surface but also inside.

[0046] An example of a method for producing a dispersion of aluminum-containing silica nanoparticles is to suspend silica nanoparticles and an aluminum salt of an organic acid and / or alumina in a solvent such as water, and then heat the mixture. In this heating process, heating in water under high temperature and pressure conditions, i.e., hydrothermal treatment, may be performed.

[0047] As for aluminum salts of organic acids, aluminum salts of oxycarboxylic acids are preferred. Examples of aluminum salts of organic acids include aluminum lactate, aluminum citrate, aluminum malate, basic aluminum lactate, aluminum citrate lactate, aluminum glycolate lactate, aluminum glycolate, and aluminum salts of tartaric acid, and one or more of these may be used.

[0048] Examples of alumina include commercially available aluminum hydroxide or aluminum oxide hydrates, or alumina hydrate gel obtained by neutralizing aluminum salts, and those that are readily soluble in water are preferred.

[0049] The aluminum-containing silica nanoparticles are preferably spherical in shape.

[0050] The hydrodynamic diameter of the aluminum-containing silica nanoparticle dispersion is preferably 5 nm to 80 nm, and more preferably 15 nm to 60 nm.

[0051] The solvent used when forming a dispersion of aluminum-containing silica nanoparticles is preferably the solvent used to form a dispersion of silica nanoparticles, as described later in section 5.

[0052] The aluminum-containing silica nanoparticle dispersion preferably has a zeta potential of +1 mV to 70 mV in an aqueous solution at pH 7, and more preferably +20 mV to 50 mV.

[0053] The pH of the aluminum-containing silica nanoparticle dispersion is preferably 2.0 to 10.5, and more preferably 3.0 to 8.0.

[0054] A commercially available product may be used as the dispersion of aluminum-containing silica nanoparticles. A specific example of a commercially available product is "Snowtex AK" (product name) manufactured by Nissan Chemical Industries, Ltd.

[0055] 3-3. Titania nanoparticles The shape of the titania nanoparticles is preferably spherical.

[0056] The hydrodynamic diameter of the titania nanoparticle dispersion is preferably 5 nm to 80 nm, and more preferably 15 nm to 60 nm.

[0057] When using a dispersion of titania nanoparticles, the solvent used is preferably the same solvent used to disperse aggregated particles, as described later in section 5.

[0058] The pH of the titania nanoparticle dispersion is preferably 2.0 to 10.5, and more preferably 3.0 to 8.0.

[0059] A commercially available product may be used as the dispersion of titania nanoparticles. A specific example of a commercially available product is "Nano-Use OT-RA305W7-20" (product name) manufactured by Nissan Chemical Industries, Ltd.

[0060] 3-4. Zirconia Nanoparticles The shape of the zirconia nanoparticles is preferably spherical.

[0061] The hydrodynamic diameter of the zirconia nanoparticle dispersion is preferably 5 nm to 80 nm, and more preferably 15 nm to 60 nm.

[0062] When using a dispersion of zirconia nanoparticles, the solvent used is preferably the same solvent used to disperse aggregated particles, as described later in section 5.

[0063] The pH of the zirconia nanoparticle dispersion is preferably 2.0 to 10.5, and more preferably 3.0 to 8.0.

[0064] A commercially available product may be used as the dispersion of zirconia nanoparticles. A specific example of a commercially available product is "Nano-Use OZ-S20H" (product name) manufactured by Nissan Chemical Industries, Ltd.

[0065] 3-5. Chromium oxide nanoparticles The shape of the chromium oxide nanoparticles is preferably spherical.

[0066] The hydrodynamic diameter of the chromium oxide nanoparticle dispersion is preferably 5 nm to 80 nm, and more preferably 15 nm to 60 nm.

[0067] When using a dispersion of chromium oxide nanoparticles, the solvent used is preferably the same solvent used to disperse aggregated particles, as described later in section 5.

[0068] The pH of the chromium oxide nanoparticle dispersion is preferably 2.0 to 10.5, and more preferably 3.0 to 8.0.

[0069] A commercially available product may be used as the dispersion of chromium oxide nanoparticles. A specific example of a commercially available product is "Chromium Oxide (III)" (product name, product number 634239) manufactured by Sigma-Aldrich Japan LLC, which can be dispersed in a solvent used to disperse aggregated particles as described later in section 5.

[0070] 3-6. Alumina nanoparticles The shape of the alumina nanoparticles is preferably spherical.

[0071] The hydrodynamic diameter of the alumina nanoparticle dispersion is preferably 5 nm to 80 nm, and more preferably 15 nm to 60 nm.

[0072] When using a solvent to disperse alumina nanoparticles, the solvent used is preferably the same solvent used to disperse aggregated particles, as described later in section 5.

[0073] The pH of the alumina nanoparticle dispersion is preferably 2.0 to 10.5, and more preferably 3.0 to 8.0.

[0074] A commercially available product may be used as the dispersion of alumina nanoparticles. A specific example of a commercially available product is "AS-520-A" (product name) manufactured by Nissan Chemical Industries, Ltd.

[0075] 4. Ceria nanoparticles on which a boron compound, heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on the surface. 4-1. Ceria nanoparticles In the present invention, ceria nanoparticles are CeO ２ Structure or Ce as described in ２ O ３ and CEO ２ It has a structure composed of a mixture of these, and a structure on which a boron compound, heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on its surface. ２ O ３ and CEO ２The ratio can be calculated as the ratio of cerium(III) to cerium(IV) by X-ray photoelectron spectroscopy (XPS) or the like. Ceria nanoparticles may also exist in the form of hydroxides or oxyhydroxides in addition to the oxide form described above. The oxide may exist in a crystalline structure or an amorphous state.

[0076] The hydrodynamic diameter of the ceria nanoparticles in a dispersion is 1 nm or more and 1000 nm or less, preferably 1 nm or more and 300 nm or less, more preferably 1 nm or more and 200 nm or less, even more preferably 1 nm or more and 150 nm or less, and most preferably 1 nm or more and 100 nm or less.

[0077] When ceria nanoparticles are dispersed, it is preferable that the zeta potential value in an aqueous solution at pH 7 is between -5 mV and +5 mV.

[0078] The pH of the ceria nanoparticle dispersion is preferably 2.0 to 7.0, and more preferably 2.0 to 6.0.

[0079] In this specification, a component that is adsorbed onto particles in order to stably disperse them as a dispersion is referred to as a "stabilizer."

[0080] In this invention, "adsorption" refers to the observation of elements derived from the stabilizer when the surface structure of the particles is analyzed. Ceria nanoparticles in which the stabilizer components are contained not only on the surface but also inside are also included in "ceria nanoparticles with adsorbed stabilizer components."

[0081] In the present invention, boron compounds, heterocyclic amines, nitric acid, acetic acid, or phthalic acid act as stabilizers for ceria nanoparticles.

[0082] The aggregate particles of the present invention contain the above-mentioned ceria nanoparticles and therefore possess antiviral properties.

[0083] Ceria nanoparticles can be manufactured as a dispersion. Water and / or a water-compatible solvent are preferred as the solvent, or dispersion medium, used to prepare the ceria nanoparticle dispersion. Examples of water-compatible solvents include those mentioned above, which can be used when preparing a dispersion of metal oxide a nanoparticles.

[0084] Ceria nanoparticles can be produced by forming nanoparticles in the presence of a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid (hereinafter referred to as "pre-addition"). Alternatively, ceria nanoparticles can also be produced by adding a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid to the formed nanoparticles (hereinafter referred to as "post-addition"). Ceria nanoparticles produced by "pre-addition" are preferred.

[0085] A solution containing cerium(III) ions can be prepared by dissolving a cerium(III) salt in any solvent. For example, cerium(III) nitrate hexahydrate can be used as the cerium(III) salt.

[0086] Examples of oxidizing agents include nitric acid, potassium nitrate, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, halogens, permanganates, chromic acid, dichromate, oxalic acid, sulfur dioxide, sulfuric acid, hydrogen peroxide, oxygen, and ozone. Among these, hydrogen peroxide is particularly preferred.

[0087] When producing ceria nanoparticles, the adsorption of boron compounds, heterocyclic amines, nitric acid, acetic acid, or phthalic acid can also be promoted by heating the aqueous solution or changing its pH.

[0088] 4-2. Boron Compounds In this specification, boron compounds refer to all compounds that contain a boron atom.

[0089] As the boron compound, those described in Patent Document 1 can be used. A specific example of a boron compound is the boron compound shown in general formula (I).

[0090] BR ｎ (OR') ３－ｎ(I) In general formula (I), n is an integer from 0 to 2, R represents an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a tolyl group, and R' represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a tolyl group. Multiple R or R' may be the same or different. The tolyl group may be an o-tolyl group, an m-tolyl group, or a p-tolyl group. If multiple tolyl groups are present, they may be the same or different.

[0091] More preferred embodiments of the boron compound used in the present invention include boric acid (in general formula (I), n=0, R=H, R'=H), boric acid ester (in general formula (I), n=0, R=H, R'=alkyl, etc.), boronic acid (in general formula (I), n=1, R=alkyl, etc., R'=H), boronic acid ester (in general formula (I), n=1, R=alkyl, etc., R'=alkyl, etc.), boric acid (in general formula (I), n=2, R=alkyl, etc., R'=H), boric acid ester (in general formula (I), n=2, R=alkyl, etc., R'=alkyl, etc.), and borate.

[0092] In this invention, "borate" refers to a general term including salts of boric acid, or salts of metaboric acid and polyboric acid obtained by dehydration condensation of boric acid. Since these borates exist in equilibrium with boric acid and tetrahydroxyboric acid in aqueous solution, they take on the structure of boric acid shown in general formula (I) in solution. Any ion such as lithium ions, sodium ions, potassium ions, or ammonium ions can be used as the counterion of boric acid in borates.

[0093] Examples of such boron compounds include boric acid; boric acid esters such as trimethyl borate, triethyl borate, tripropyl borate, triisopropyl borate, tributyl borate, and triisobutyl borate; and boronic acids such as methylboronic acid, ethylboronic acid, propylboronic acid, isopropylboronic acid, butylboronic acid, isobutylboronic acid, and phenylboronic acid. Examples of borates include lithium salts, sodium salts, potassium salts, and ammonium salts of boric acid, metaboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, hexaboric acid, and octaboric acid.

[0094] The ceria nanoparticles of the present invention, on which a boron compound is adsorbed on the surface, preferably contain 0.001 moles to 10 moles of the boron compound per mole of cerium atoms. More preferably, the amount is in the range of 0.001 moles to 1 mole.

[0095] 4-3. Heterocyclic amines In this specification, a heterocyclic amine refers to a compound that contains at least one heterocycle and has at least one amine functional group.

[0096] Heterocyclic amines include alicyclic amines represented in general formula (III) described in Patent Document 4, aromatic heterocyclic compounds described in Patent Document 3, and vinyl polymers or polyamides having a heterocyclic amine skeleton described in Patent Document 2.

[0097]

[0098] In general formula (III), X is NR ４ , indicates O or S, R ３ and R ４ R represents a hydrogen atom, a C1-C4 alkyl group, a C1-C4 hydroxyalkyl group, a C1-C4 aminoalkyl group, or a C1-C4 sulfonic acid alkyl group. ３ and R ４ They may be the same or different.

[0099] A preferred alicyclic amine is one in which X is NR in the above general formula (III). ４ Or indicate O, R ３ and R４ R represents a hydrogen atom, a C1-C2 alkyl group, a C2-C3 hydroxyalkyl group, a C2-C3 aminoalkyl group, or a C2-C3 sulfonic acid alkyl group. ３ and R ４ These may be the same or different. Examples of such alicyclic amines include piperazine, 1-methylpiperazine, N,N'-dimethylpiperazine, 1-ethylpiperazine, N,N'-diethylpiperazine, 1-(2-hydroxyethyl)piperazine, 1,4-bis(2-hydroxyethyl)piperazine, N-(2-aminoethyl)piperazine, 1,4-bis(2-aminoethyl)piperazine, 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid, piperazine-1,4-bis(2-ethanesulfonic acid), morpholine, 4-methylmorpholine, 4-ethylmorpholine, 4-(2-aminoethyl)morpholine, 4-(2-hydroxyethyl)morpholine, 2-morpholinoethanesulfonic acid, and 3-morpholinopropanesulfonic acid.

[0100] Preferred aromatic heterocyclic compounds contain 2 to 8 carbon atoms and 1 to 4 nitrogen atoms in their ring structure. The aromatic heterocyclic may be fused with a benzene ring or a thiophene ring. More preferred aromatic heterocyclic compounds are monocyclic or bicyclic compounds having a 5-membered ring and / or a 6-membered ring structure, in addition to the above. Specific examples of aromatic heterocyclic compounds include pyrrole, pyrimidine, pyridazine, imidazole, triazole, triazine, tetrazole, thiazole, pyrazole, isothiazole, oxazole, isoxazole, thiadiazole, oxadiazole, purine, indole, isoindole, benzimidazole, indazole, quinol, isoquinol, quinazoline, quinoxaline, phthalazine, benzothiazole, benzoisothiazole, benzothiadiazole, benzoxazole, benzoisoxazole, benzofuranil, benzotriazole, carbazole, dibenzo[b,d]furan, 1,2,4-triazolo[4,3-a]pyridine, and the like.

[0101] A more preferred embodiment of a vinyl polymer or polyamide having a heterocyclic amine skeleton is a vinyl polymer or polyamide having a heterocyclic amine skeleton R'' such as piperazine, pyridine, imidazole, or carbazole in the main chain (Figure 1(a)) or side chains (Figures 1(b) and (c)), as shown in Figure 1. The vinyl polymer or polyamide according to the present invention may have substituents at any position on the main chain or side chain, or substituents at any position on the heterocyclic amine skeleton such as piperazine, pyridine, imidazole, or carbazole. In the polymer shown in Figure 1(a), the main chain has a heterocyclic amine skeleton and the side chain has substituent R''. ５ and R ６ The polymer shown in Figure 1(b) has a heterocyclic amine skeleton in its side chain, and substituent R is a substituent on the heterocyclic amine skeleton. ６ The polymer shown in Figure 1(c) has a heterocyclic amine skeleton in the side chain, and the heterocyclic amine skeleton has substituents R in the side chain. ５ A substituent of the heterocyclic amine skeleton, wherein substituent R ７ It has the following properties. The structures shown in Figures 1(a) to (c) are examples of vinyl polymers or polyamides used as stabilizers, but are not limited thereto.

[0102] Vinyl polymers having a heterocyclic amine skeleton are polymers that have methylene groups in their main chain. As an example, the structures of vinyl polymers having a piperazine skeleton in their main chain or side chain are shown in Figures 2(a) and (b). As shown in Figure 2(a), when the main chain has a piperazine skeleton, the piperazine skeleton is located between the methylene groups of the main chain. When the main chain has other heterocyclic amine skeletons such as pyridine, imidazole, or carbazole skeletons, the heterocyclic amine skeleton is located between the methylene groups, similar to Figure 2(a).

[0103] Vinyl polymers are preferred if they have a piperazine, pyridine, imidazole, or carbazole skeleton in their side chains. Vinyl polymers having a piperazine, pyridine, imidazole, or carbazole skeleton in their side chains are obtained by polymerization reactions of vinyl monomers having vinyl groups.

[0104] Polyamides are polymers that have amide bonds in their main chain. As shown in Figure 2(c), when the main chain has a piperazine skeleton, the piperazine skeleton is located between the carbonyl groups of the main chain, and the nitrogen in the heterocyclic piperazine skeleton and the carbonyl groups form an amide bond. When the main chain has other heterocyclic amine skeletons having two or more primary or secondary amino groups, such as pyridine, imidazole, or carbazole skeletons, the heterocyclic amine skeleton is located between the carbonyl groups, similar to Figure 2(c).

[0105] When the polyamide has a piperazine skeleton, as shown in Figure 2(d), the piperazine skeleton may be directly bonded to the carbon linking the amide group, or it may be bonded via an alkyl group or an amino group. When it has other heterocyclic amine skeletons such as pyridine, imidazole, or carbazole skeletons, similarly to Figure 2(d), the heterocyclic amine skeleton such as pyridine, imidazole, or carbazole skeleton may be directly bonded to the carbon linking the amide group, or it may be bonded via an alkyl group or an amino group.

[0106] The polyamide is preferably a polymer having a piperazine skeleton in its main chain or side chains, and more preferably a polymer having a piperazine skeleton in its main chain, as shown in Figure 2(c).

[0107] Furthermore, the polyamide may be a mixture or copolymer of a polyamide having a heterocyclic amine skeleton, such as piperazine, pyridine, imidazole, or carbazole, and other polymers.

[0108] The weight-average molecular weight of the vinyl polymer or polyamide used in the present invention may be 3,000 or more and 1,000,000 or less, and preferably 10,000 or more and 50,000 or less.

[0109] When using a polymer having a heterocyclic amine skeleton as used in the present invention, the concentration of the polymer solution should be 0.001% or more and 50% or less by mass, preferably 0.01% or more and 5% or less, and more preferably 0.1% or more and 2% or less.

[0110] 4-4. Nitric acid, acetic acid, or phthalic acid The ceria nanoparticles of the present invention, on which nitric acid, acetic acid, or phthalic acid is adsorbed on the surface, preferably contain 0.001 moles or more and 10 moles or less per mole of cerium atoms. More preferably, the range is 0.001 moles or more and 1 mole or less.

[0111] 5. Aggregated Particle Dispersion The aggregated particle dispersion of the present invention is manufactured by mixing a dispersion of nanoparticles of metal oxide a with a dispersion of ceria nanoparticles on which a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on the surface. Embodiments of the present invention include the above manufacturing method and the aggregated particle dispersion manufactured by said method.

[0112] The aggregate particle dispersion of the present invention is a concept that includes a silica-ceria particle dispersion produced by mixing a dispersion of aminosilica nanoparticles or aluminum-containing silica nanoparticles with a dispersion of ceria nanoparticles on which a boron compound and / or heterocyclic amine is adsorbed on the surface.

[0113] In the manufacturing method of the present invention, nanoparticles of metal oxide a are used as a dispersion in a solvent. The dispersion of nanoparticles of metal oxide a can be produced by the method described in 3. to 3-6.

[0114] In the manufacturing method of the present invention, ceria nanoparticles are used as a dispersion in a solvent. The dispersion of ceria nanoparticles can be produced by the method described in 4-1.

[0115] In the production of aggregate particle dispersions, a dispersion of aminosilica nanoparticles or aluminum-containing silica nanoparticles is mixed with a dispersion of ceria nanoparticles on which a boron compound, heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on the surface, or a dispersion of metal oxide a nanoparticles is mixed with the ceria nanoparticle dispersion. The mixed solution after the addition is preferably mixed for 5 minutes or more until the aggregate particles are uniformly dispersed.

[0116] In the aggregate particles of the present invention, the mass ratio of ceria nanoparticles to metal oxide a nanoparticles is preferably 30 to 900 when the ceria nanoparticles are set to 100. When this mass ratio is within this range, the metal oxide a nanoparticles are sufficiently adsorbed onto the ceria nanoparticles, and the dispersion stability of the aggregate particles of the present invention in the alkaline region is good. When producing aggregate particles or aggregate particle dispersions by the method of the present invention, this mass ratio can be controlled by adjusting the concentrations of metal oxide a and cerium in the metal oxide a nanoparticle dispersion and the ceria nanoparticle dispersion, as well as the amount of each dispersion added.

[0117] The aggregate particle dispersion of the present invention may also be used as a dispersion by redispersing the aggregate particles, which were isolated once in the method described later in section 6, in a solvent. Examples of solvents that can be used in this case include water and / or an organic solvent that is compatible with water. In other words, both the aggregate particle dispersion obtained in section 5 by the manufacturing method described above, and the dispersion obtained by redispersing the aggregate particles isolated from the aggregate particle dispersion in a solvent, are considered aggregate particle dispersions of the present invention.

[0118] As a solvent for dispersing the aggregate particles of the present invention, i.e., a dispersion medium, water and / or a water-compatible solvent are preferred. Examples of water-compatible solvents include those mentioned above, which can be used when forming a dispersion of silica nanoparticles.

[0119] The hydrodynamic diameter of the aggregated particle dispersion of the present invention is preferably 1 nm to 250 nm, and more preferably 1 nm to 100 nm.

[0120] The pH of the aggregated particle dispersion of the present invention is preferably 2.0 or more and 10.5 or less, more preferably 3.0 or more and 10.0 or less, even more preferably 5.0 or more and 9.5 or less, and most preferably 7.0 or more and 9.0 or less.

[0121] The aggregated particle dispersion of the present invention may contain any components other than organic substances. Specifically, it may contain inorganic solvents, wetting agents, thickeners, antioxidants, pH adjusters, preservatives, sweeteners, fragrances, surfactants, colorants, bactericidal enhancers, chelating agents, UV absorbers, defoamers, formulation stabilizers, and the like.

[0122] The aggregated particle dispersion of the present invention can be provided in sol-like or gel-like forms.

[0123] 6. Isolation of Aggregate Particles The aggregate particles of the present invention can be isolated by removing the solvent from the aggregate particle dispersion obtained by the above method. An evaporator or freeze-dryer can be used to remove the solvent from the dispersion. Aggregate particles can also be isolated by dropping the aggregate particle dispersion of the present invention onto a substrate such as glass, plastic, or ceramics and air-drying, drying in a desiccator, or drying with a dryer or drying oven. Furthermore, the aggregate particle dispersion of the present invention can also be isolated by dropping it onto a heat block and heating it to volatilize the solvent. Furthermore, the aggregate particle dispersion of the present invention can also be isolated by volatilizing the solvent with a spray dryer or the like. Furthermore, the dispersion of the present invention can be isolated by centrifuging it to precipitate cerium oxide nanoparticles and removing the supernatant. Furthermore, aggregate particles can be isolated on a filtration membrane by filtering the aggregate particle dispersion of the present invention by ultrafiltration or suction filtration to completely remove the solvent. To improve the efficiency of solvent removal by volatilization in the above operations, an azeotropic solvent may be added to the aggregate particle dispersion of the present invention, or the solvent in the aggregate particle dispersion may be replaced with a solvent with a lower boiling point. Furthermore, to improve the efficiency of the centrifugation operation, a coprecipitant may be added to the aggregated particle dispersion of the present invention, or a solvent that improves ionic strength or reduces the dispersibility of nanoparticles may be added. In addition, before the above operations, the aggregated particle dispersion of the present invention may be fractionated by ultrafiltration or centrifugation to separate the nanoparticle sizes.

[0124] 7. Aspects of the present invention include a paint containing aggregate particles, which includes aggregate particles of the present invention.

[0125] Furthermore, aspects of the present invention include paints obtained by mixing the aggregate particle dispersion of the present invention with a binder resin. These paints are referred to herein as aggregate particle-containing paints.

[0126] In the present invention, because the aggregate particles in the paint are stably dispersed, it is possible to form a uniform coating surface without compromising the aesthetic appeal due to particle aggregation.

[0127] Examples of binder resins that can be used include acrylic resins, styrene-acrylic resins, acrylic-silicone resins, vinyl acetate resins, styrene resins, ethylene resins, ethylene-vinyl acetate resins, propylene resins, ester resins, epoxy resins, olefin resins, phenolic resins, amide resins, vinyl alcohol resins, fluororesins, urethane resins, melamine resins, phthalic acid resins, silicone resins, alkyd resins, and vinyl chloride resins.

[0128] The aggregate particle-containing coating of the present invention preferably comprises additives, pigments, dyes and / or solvents in addition to the aggregate particle dispersion and binder resin of the present invention.

[0129] Examples of additives include thixotropes, defoamers, leveling agents, dispersants, and electrostatic additives.

[0130] Examples of pigments include coloring pigments, extender pigments, rust-inhibiting pigments, and aggregates, and these may be used in combination.

[0131] Examples of dyes include direct dyes, reactive dyes, vat dyes, metal-containing dyes, and disperse dyes, and these may be used in combination.

[0132] Examples of solvents used in paints containing aggregated particles include water and / or organic solvents. Examples of organic solvents include alcohols such as methanol, ethanol, isopropanol, n-butanol, and methylisocarbinol; ketones such as acetone, 2-butanone, ethyl amyl ketone, diacetone alcohol, isophorone, and cyclohexanone; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; ethers such as diethyl ether, isopropyl ether, tetrahydrofuran, 1,4-dioxane, and 3,4-dihydro-2H-pyran; glycol ethers such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, and ethylene glycol dimethyl ether; and 2-methoxyethyl acetate and 2-ethoxyethanol. Synthetic organic solvents such as glycol ether acetates including ethyl acetate and 2-butoxyethyl acetate; esters such as methyl acetate, ethyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, and ethylene carbonate; aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, isooctane, and cyclohexane; halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, dichloropropane, and chlorobenzene; sulfoxides such as dimethyl sulfoxide; and pyrrolidones such as N-methyl-2-pyrrolidone and N-octyl-2-pyrrolidone, as well as natural organic solvents such as turpentine oil and petrol oil, can be used.

[0133] The present invention provides a method for producing a paint containing aggregate particles, which may involve adding a binder resin to an aggregate particle dispersion or adding the aggregate particle dispersion to a binder resin. The mixed solution after addition is preferably mixed for at least five minutes until the nanoparticles are uniformly dispersed.

[0134] The aggregate particles of the present invention are included in the aggregate particle-containing coating of the present invention at a final concentration of 0.001% by mass or more and 50% by mass or less, preferably at 0.01% by mass or more and 20% by mass or less.

[0135] 8. Method for forming an antiviral surface using the aggregate particle-containing coating of the present invention The ceria nanoparticles contained in the aggregate particle-containing coating of the present invention have antiviral properties, as described in Patent Documents 1 to 4. Therefore, when the aggregate particle-containing coating of the present invention is applied to a solid surface, an antiviral surface can be formed due to the antiviral activity of the ceria nanoparticles contained in the coating.

[0136] Regardless of the pH of the binder resin added to the paint of the present invention, the paint and surface of the present invention possess the high oxidizing properties of the ceria nanoparticles it contains. Therefore, the paint and surface of the present invention exhibit antiviral properties against viruses, including non-enveloped viruses, by decomposing viral proteins.

[0137] Application methods include spraying the solution after filling it into a measuring cap bottle, trigger-type spray container, or squeeze-type or dispenser-type pump spray container; applying it by impregnating or attaching it to a sheet, roller, or mop-type brush, fiber, or spatula; and immersing the object in a container such as a bottle or bucket. In the case of spraying or spreading, the antiviral surface is formed after the solvent evaporates, and in the case of immersion, the surface is formed after the object is removed and dried. At this time, moisture may be removed by dry wiping or blow-drying.

[0138] The solid surface on which the aggregate particle-containing coating of the present invention can form an antiviral surface is not particularly limited. Examples of solid surfaces to which the aggregate particle-containing coating of the present invention can be applied include metal products made of iron, copper, etc., polymer compounds made of resin, rubber, etc., wood products, mortar products, glass products, and fibrous products such as nonwoven fabrics.

[0139] Examples of the antiviral surfaces of the present invention include furniture such as tables, chairs, and cabinets; outdoor items such as automobiles, ships, airplanes, and outdoor playground equipment; exterior and interior walls of buildings such as hospitals; equipment that handles viruses; and building materials such as doors, doorknobs, handrails, stairs, ceiling panels, floor panels, and windows, which are surfaces obtained by applying the aggregate particle-containing coating of the present invention.

[0140] One method for confirming that the application of the aggregate particle-containing coating of the present invention has been completed is to check whether or not precipitates are observed on the surface after application and drying. If no precipitates are observed, it can be inferred that the aggregate particles have been fixed to the solid surface, creating an antiviral surface.

[0141] One method for confirming that an antiviral surface is formed by applying the aggregate particle-containing coating of the present invention is to evaluate the antiviral performance of the surface after application and drying. The aggregate particle-containing coating of the present invention is preferably characterized in that the antiviral activity value of the surface formed by application is 2.0 or higher according to the ISO 21702 or ISO 18184 method. Methods for evaluating antiviral performance generally include measuring the amount of viral antigen by the ELISA method, quantifying viral nucleic acid by PCR, measuring the infectivity titer by the plaque method, and measuring the infectivity titer by the 50% infectious dose method. In the present invention, the plaque method or the 50% infectious dose method, as defined by ISO 21702 or ISO 18184, is preferably used to measure the infectivity titer. Generally, the criteria for determining antiviral activity is that if the logarithmic decrease in the infectivity titer of a solid surface coated with the aggregate particle-containing coating of the present invention compared to a control that does not contain the antiviral agent ceria nanoparticles is 2.0 or higher, the antiviral performance is judged to be effective. In this invention, the logarithmic reduction in infectivity compared to a control without ceria nanoparticles is used for determination. A logarithmic reduction in infectivity in the virus inactivation test of 2.0 or higher is sufficient, and 3.0 or higher is more preferable.

[0142] Viruses that can be inactivated by the aggregate particles, aggregate particle dispersions, and aggregate particle-containing paints of the present invention include, for example, rhinovirus, poliovirus, foot-and-mouth disease virus, rotavirus, norovirus, enterovirus, hepatovirus, astrovirus, sapovirus, hepatitis E virus, influenza A, B, and C viruses, parainfluenza virus, mumps virus, measles virus, human metapneumovirus, RSV, Nipah virus, Hendra virus, yellow fever virus, dengue virus, Japanese encephalitis virus, West Nile virus, hepatitis B and C viruses, eastern and western equine encephalitis viruses, Onyonyon virus, rubella virus, and Lassa virus. Examples include Junin virus, Machupo virus, Guanalito virus, Sabia virus, Crimean-Congo hemorrhagic fever virus, sandfly fever virus, Hantavirus, Sin Nombre virus, rabies virus, Ebola virus, Marburg virus, bat lyssavirus, human T-cell leukemia virus, human immunodeficiency virus, human coronavirus, SARS coronavirus, SARS coronavirus 2, human porvovirus, polyomavirus, human papillomavirus, adenovirus, herpesvirus, varicella-zoster virus, EB virus, cytomegalovirus, smallpox virus, monkeypox virus, cowpox virus, molasipox virus, and parapoxvirus. These viruses can be inactivated by any of the aggregate particles, aggregate particle dispersion, paint, or antiviral surface of the present invention.

[0143] The aggregate particle-containing coating of the present invention can be used to decompose and remove viruses, odors, allergens, bacteria, fungi, mold, etc. from the surface of products. Specific examples of products to which the coating of the present invention can be applied include furniture such as tables, chairs, and cabinets; automobiles, ships, airplanes; outdoor products such as outdoor playground equipment; exterior and interior walls of buildings such as hospitals; equipment that handles bacteria and viruses; and building materials such as doors, doorknobs, handrails, stairs, ceiling panels, floor panels, and windows.

[0144] The aggregate particle-containing coating of the present invention can also be used as a rust inhibitor. Specific examples include automobiles, ships, airplanes, outdoor products such as playground equipment, exterior and interior walls of buildings such as hospitals, equipment that handles bacteria and viruses, and building materials such as doors, doorknobs, and ceiling panels.

[0145] 9. Method for forming an anti-allergenic surface using the aggregate particle-containing paint of the present invention Regardless of the pH of the binder resin added to the paint of the present invention, the paint and surface of the present invention have high oxidation performance derived from the ceria nanoparticles they contain. For this reason, the aggregate particles of the present invention exhibit anti-allergenic properties by decomposing proteins, which are allergenic substances. For this reason, when the aggregate particle-containing paint of the present invention is applied to a solid surface, an anti-allergenic surface can be formed due to the anti-allergenic properties of the ceria nanoparticles contained in the paint.

[0146] The application method, the solid surface, and the method for confirming that the application is complete are as described above in section 8. Method for forming an antiviral surface.

[0147] One method for confirming that an anti-allergen surface is created by applying the aggregate particle-containing coating of the present invention is to evaluate the anti-allergen activity value of the surface after application and drying.

[0148] The preferred anti-allergen activity value of the anti-allergen surface of the present invention is 70% or higher, as measured by the following steps 1 to 3.

[0149] Step 1: A supply step in which a test solution containing an allergen is supplied to the surface to be measured on the anti-allergenic surface. Step 2: A reaction step in which a covering film is placed over the surface to be measured on the anti-allergenic surface to which the test solution has been supplied, and the allergen in the test solution is reacted with the anti-allergen agent on the surface to be measured on the anti-allergenic surface while the test solution is spread between the covering film and the surface to be measured. Step 3: A measurement step in which the test solution after the reaction is collected and the anti-allergen activity value is measured by enzyme immunoassay (ELISA). In steps 1 to 3 above, the size of the test substrate is not particularly limited, but the surface area of ​​the test substrate is 4 to 225 cm². ２ Preferably 9 to 100 cm ２This is appropriate. The shape is not particularly limited, but it is usually a square with sides of 2 to 15 cm, preferably a square with sides of 3 to 10 cm. However, a circular or rectangular shape is also acceptable, and an irregular shape is also acceptable as long as it does not hinder contact between the allergen aqueous solution and the test substrate.

[0150] The test solution containing the allergen used can be arbitrarily selected within a range where the amount of liquid necessary for measuring the amount of allergen can be recovered. This amount of liquid correlates with the surface area of ​​the test substrate; the larger the surface area, the greater the amount of liquid that can be used. Approximately 100 μL is often required to measure the amount of allergen, and it is preferable to use 100 μL or more of liquid in the test to ensure a sufficient amount for measurement.

[0151] Next, the test solution containing the allergen and the test substrate are brought into contact for a certain period of time. The contact time can be set to any desired duration, but it is usually set in the range of 5 minutes to 72 hours, preferably 30 minutes to 24 hours, and more preferably 1 hour to 3 hours. When setting a long contact time, the test solution containing the allergen may decrease due to volatilization or evaporation, potentially changing the allergen concentration. Therefore, it is preferable to store the test substrate in a sealed container while the contact is taking place. Such a sealed container is not particularly limited, but examples include a glass chamber, a glass desiccator, and a polyethylene bag with a zipper. Furthermore, if the volume of the sealed container is relatively large and the amount of test solution containing the allergen is small, the decrease due to volatilization of the test solution may affect the test even in a sealed container. Therefore, it is preferable to include water-soaked cotton wool or a container of water to regulate and prevent humidity inside the sealed container.

[0152] The temperature at which the allergen-containing test solution is brought into contact with the test substrate is not particularly limited, but it is preferable to do so at room temperature to suppress the volatilization of the allergen-containing test solution. It can usually be set arbitrarily within the range of 5 to 37°C, preferably 15 to 25°C. After the allergen-containing test solution is brought into contact with the test substrate, the allergen-containing test solution is recovered. Recovery can be done using a micropipette, and if some of the allergen-containing test solution is absorbed by the test substrate and recovery is difficult, it is also possible to compress the test substrate to squeeze out the allergen-containing test solution. The method of compressing the test substrate is not particularly limited, but it can be done by hand, or by using a vise or other tool.

[0153] Furthermore, methods for evaluating anti-allergen activity include generally measuring the amount of allergen antigen by ELISA, amplifying and detecting DNA derived from a specific allergen by PCR, and separating proteins by electrophoresis and then detecting a specific allergen using an antibody. In this case, preferably, the anti-allergen activity of the solid surface coated with the aggregate particle-containing coating of the present invention is 70% or more of the anti-allergen activity of the solid surface before coating with the aggregate particle-containing coating of the present invention, or the anti-allergen activity of a control solid surface coated with a coating that does not contain anti-allergen ceria nanoparticles.

[0154] The allergens that can be inactivated by the aggregate particles, aggregate particle dispersions, and aggregate particle-containing coatings of the present invention are not particularly limited, but examples include dust mites, pollen, mold, and house dust such as pet hair. In the case of dust mite allergens, house dust mites such as Der pteronyssinus and Der hepatica are usually the cause of the allergen, and examples of allergen proteins include Der f1 derived from the feces of Der pteronyssinus and Der f2 derived from the insect body of Der pteronyssinus. A typical example of a pollen allergen is cedar pollen allergen, and Cry j1, which is mainly present in the outer layer of cedar pollen, is an example of an allergen protein. Other plant species from which pollen that causes allergens are derived include cypress, mugwort, ragweed, sweet vernal grass, and orchard grass. Other allergens besides dust mite allergens and pollen allergens include mold and dog and cat dander. Examples of these allergen proteins include Can f1 derived from dog dander, Fel d1 derived from cat dander, and ASP f1 derived from mold. These allergens can be reduced by any of the aggregate particles, aggregate particle dispersion, paint, or anti-allergenic surface of the present invention.

[0155] The present invention will be further described in detail by the following examples.

[0156] <Materials and Methods> Cerium(III) nitrate hexahydrate, nitric acid, boric acid, and 30% by weight hydrogen peroxide solution were obtained from Fujifilm Wako Pure Chemical Corporation, and cerium oxide powder was obtained from Daiichi Rare Elements Chemical Industry Co., Ltd. Poly(1-vinylimidazole) was obtained from Maruzen Petrochemical Co., Ltd. Trisodium citrate was obtained from Fujifilm Wako Pure Chemical Corporation. Amicon Ultra 15 (10 kD) used for purification was purchased from Merck Millipore. Silica and nanoparticle dispersion in water were obtained from Sigma-Aldrich Japan LLC, and Snowtex AK and Snowtex O were obtained from Nissan Chemical Industries, Ltd.

[0157] Other reagents were purchased from Fujifilm Wako Pure Chemical Corporation, Kanto Chemical Co., Ltd., Nacalai Tesque Co., Ltd., Tokyo Chemical Industry Co., Ltd., or Sigma-Aldrich Japan LLC, and were used without any special purification.

[0158] The hydrodynamic diameter and zeta potential of the particles were measured using the ELSZ-2000ZS zeta potential and particle measurement system from Otsuka Electronics Co., Ltd.

[0159] (Reference Example 1) Preparation of a dispersion of ceria nanoparticles using boric acid as a stabilizer. This was prepared based on Patent Document 1. 2.8 g of boric acid was dissolved in 500 mL of water and the pH was adjusted to 8.0 with sodium hydroxide. 1 g of cerium(III) nitrate hexahydrate was added. 10 mL of 1.2% hydrogen peroxide solution was added dropwise to obtain an orange aqueous solution. 1 M nitric acid was added to adjust the pH to 2.0, and the reaction solution was purified using an ultrafiltration membrane with a molecular weight cutoff of 10 kD to obtain a dispersion of cerium oxide nanoparticles (orange) using boric acid as a stabilizer. This dispersion was transferred to a pressure vessel and subjected to hydrothermal treatment at 120°C (199 kPa) for 20 minutes to obtain a dispersion of ceria nanoparticles using boric acid as a stabilizer. The obtained dispersion was transparent. The average particle size (cumulant diameter) of the hydrodynamic diameter was 16.4 nm.

[0160] (Reference Example 2) A dispersion containing ceria nanoparticles stabilized with poly(1-vinylimidazole) was prepared based on Patent Document 2. As an aqueous solution of a polymer having an imidazole skeleton, which is a heterocyclic amine skeleton, a 0.1% by mass aqueous solution of poly(1-vinylimidazole) was used. To 500 ml of the 0.1% by mass aqueous solution of poly(1-vinylimidazole), 10 ml of a 10% by mass aqueous solution of cerium(III) nitrate hexahydrate was added and the mixture was stirred at room temperature for 5 minutes. Then, 10 ml of a 1.2% by mass aqueous solution of hydrogen peroxide was added and the mixture was heated to 60°C and reacted for 1 hour to obtain an orange aqueous solution. The reaction solution was purified using a 30 kD ultrafiltration membrane to obtain a dispersion of cerium oxide nanoparticles (orange) stabilized with poly(1-vinylimidazole). This dispersion was transferred to a pressure vessel and subjected to hydrothermal treatment at 120°C (199 kPa) for 20 minutes to obtain a dispersion of ceria nanoparticles stabilized with imidazole. The obtained dispersion was transparent. The average particle size (cumulant diameter) of the hydrodynamic diameter was 45.7 nm.

[0161] (Reference Example 3) For the aminosilica nanoparticle dispersion, silica nanoparticles having amino groups on their surface, i.e., the aminosilica nanoparticle dispersion, we used Silica, nanoparticle dispersion in water manufactured by Sigma-Aldrich Japan LLC. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 28.4 nm.

[0162] (Reference Example 4) Aluminum-containing silica nanoparticle dispersion: Snowtex AK, manufactured by Nissan Chemical Industries, Ltd., was used as the aluminum-containing silica nanoparticle dispersion. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 67.4 nm.

[0163] (Reference Example 5) Anionic Silica Nanoparticle Dispersion In Comparative Examples 1 and 2, Snowtex O manufactured by Nissan Chemical Industries was used as the anionic silica nanoparticle dispersion, which does not contain amino groups and does not contain aluminum. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 52.4 nm.

[0164] (Reference Example 6) Production of a dispersion containing ceria nanoparticles stabilized with citric acid. As the ceria nanoparticles to be used in Comparative Example 3, 6.0 g of trisodium citrate was dissolved in 350 mL of water and the pH was adjusted to 8.0 with sodium hydroxide. 2 g of cerium(III) nitrate hexahydrate was added. 26 mL of 1.2% hydrogen peroxide solution was added dropwise to obtain a golden-colored aqueous solution. The reaction solution was purified using an ultrafiltration membrane with a molecular weight cutoff of 10 kD to obtain a dispersion of cerium oxide nanoparticles stabilized with citric acid (golden color). This dispersion was transferred to a pressure vessel and subjected to hydrothermal treatment at 120°C (199 kPa) for 20 minutes to obtain a dispersion of ceria nanoparticles stabilized with citric acid. The obtained dispersion was golden in color. The average particle size (cumulant diameter) of the hydrodynamic diameter was 25.8 nm.

[0165] (Example 1) Preparation of aggregated particle dispersion of aminosilica nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface. The dispersion of ceria nanoparticles with boric acid adsorbed on their surface, prepared in Reference Example 1, was mixed with the dispersion of aminosilica nanoparticles (Silica, nanoparticle dispersion in water), prepared in Reference Example 3, to a final particle concentration of 2.2 wt%, to obtain the aggregated particle dispersion described in the title. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 47.0 nm. The pH was 2.5. The pH was increased to 8.7 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 1. Table 2 shows that no aggregation occurred even during the pH increase process when a 0.01 M sodium hydroxide aqueous solution was added.

[0166] (Example 2) Production of aggregated particle dispersion of aluminum-containing silica nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface A dispersion of ceria nanoparticles with boric acid adsorbed on their surface, produced in Reference Example 1, was mixed with a dispersion of aluminum-containing silica nanoparticles (Snowtex AK), produced in Reference Example 4, to obtain the aggregated particle dispersion described in the title, so that the final particle concentration was 2.5 wt%, and the dispersion of ceria nanoparticles with boric acid adsorbed on their surface was mixed so that the final particle concentration was 2.2 wt%. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 61.6 nm. The pH was 2.6. The pH was increased to 8.9 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 1. Table 3 shows that no aggregation occurred even during the pH increase process when a 0.01 M sodium hydroxide aqueous solution was added.

[0167] The solvent in the obtained aggregate particle dispersion was replaced from water to ethanol, and the solvent was removed by air drying to obtain aggregate particles. The results of observing the obtained aggregate particles at 450,000x magnification using a scanning transmission electron microscope (STEM) and high-angle scattering dark-field spectroscopy (HAADF) are shown in Figure 3.

[0168] (Example 3) Production of aggregated particle dispersion in which aminosilica nanoparticles and ceria nanoparticles with poly(1-vinylimidazole) adsorbed on the surface were prepared. The dispersion of ceria nanoparticles with poly(1-vinylimidazole), a type of heterocyclic amine, adsorbed on the surface, prepared in Reference Example 2, was mixed with the dispersion of aminosilica nanoparticles (Silica, nanoparticle dispersion in water) prepared in Reference Example 3, to a final particle concentration of 2.2 wt%, to obtain the aggregated particle dispersion described in the title. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 56.7 nm. The pH was 5.1. The pH was increased to 7.6 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 1.

[0169] (Example 4) Production of aggregated particle dispersion of aluminum-containing silica nanoparticles and ceria nanoparticles with poly(1-vinylimidazole) adsorbed on the surface. The dispersion of ceria nanoparticles with poly(1-vinylimidazole), a type of heterocyclic amine, adsorbed on the surface, produced in Reference Example 2, was mixed with the dispersion of aluminum-containing silica nanoparticles (Snowtex AK) produced in Reference Example 4, to a final particle concentration of 2.2 wt%, to obtain the aggregated particle dispersion described in the title. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 80.2 nm. The pH was 5.2. The pH was increased to 7.0 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 1.

[0170] (Comparative Example 1) Production of aggregated particle dispersion in which anionic silica nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface are aggregated, instead of aminosilica nanoparticles or aluminum-containing silica nanoparticles. The dispersion of ceria nanoparticles with boric acid adsorbed on their surface, produced in Reference Example 1, was mixed with the dispersion of anionic silica nanoparticles (Snowtex O), produced in Reference Example 5, to a final particle concentration of 2.5 wt%, to a final particle concentration of 2.2 wt%, to obtain the mixed solution described in the title. The pH was 2.4. When the pH was increased by adding a 0.01 M sodium hydroxide aqueous solution, aggregation occurred. At this time, the pH was 7.0. The results are shown in Table 1.

[0171] (Comparative Example 2) Production of aggregated particle dispersion in which anionic silica nanoparticles and ceria nanoparticles with poly(1-vinylimidazole) adsorbed on the surface are aggregated instead of aminosilica nanoparticles or aluminum-containing silica nanoparticles. The dispersion of ceria nanoparticles with poly(1-vinylimidazole), a type of heterocyclic amine, adsorbed, produced in Reference Example 2, was mixed with the dispersion of anionic silica nanoparticles (Snowtex O) produced in Reference Example 5, with a final particle concentration of 2.2 wt%, to obtain the title mixture. The pH was 3.9. When the pH was increased by adding a 0.01 M sodium hydroxide aqueous solution, aggregation occurred. At this time, the pH was 7.0. The results are shown in Table 1.

[0172] (Comparative Example 3) Instead of ceria nanoparticles with boron compounds adsorbed on their surface, a dispersion of aggregated particles was prepared in which ceria nanoparticles with citric acid adsorbed on their surface and silica nanoparticles containing an aluminum compound adsorbed on their surface were aggregated. The dispersion of ceria nanoparticles with citric acid adsorbed on their surface, prepared in Reference Example 6, was mixed with the dispersion of aluminum-containing silica nanoparticles (Snowtex AK), prepared in Reference Example 4, to a final particle concentration of 2.2 wt%, to obtain the mixed solution described in the title. The pH was 5.7. When the pH was increased by adding a 0.01 M sodium hydroxide aqueous solution, aggregation occurred. At this time, the pH was 7.0. The results are shown in Table 1.

[0173] (Comparative Example 4) Production of a dispersion of ceria nanoparticles with boron compounds adsorbed on the surface The dispersion of ceria nanoparticles with boric acid adsorbed, produced in Reference Example 1, was diluted with water without adding silica nanoparticles to a final particle concentration of 2.5 wt%. The pH was 2.3. When the pH was gradually increased by adding a 0.01 M sodium hydroxide aqueous solution, aggregation occurred in the acidic region. Subsequently, the pH was set to 7.4. The results are shown in Table 1.

[0174] (Comparative Example 5) Production of a dispersion of ceria nanoparticles with poly(1-vinylimidazole) adsorbed on the surface. The dispersion of ceria nanoparticles with poly(1-vinylimidazole) adsorbed on the surface, produced in Reference Example 2, was diluted with water without adding silica nanoparticles to a final particle concentration of 2.5 wt%. The pH was 5.3. When the pH was gradually increased by adding a 0.01 M sodium hydroxide aqueous solution, aggregation occurred in the acidic region. Subsequently, the pH was set to 7.1. The results are shown in Table 1.

[0175]

[0176]

[0177]

[0178] (Example 5) Preparation of a paint containing aggregated particle dispersion in which aluminum-containing silica nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface are aggregated. The aggregated particle dispersion prepared in Example 2 was adjusted to a final concentration of 1.9 wt%, and the polyurethane aqueous dispersion as a binder resin was adjusted to a final concentration of 0.1 wt%, thereby preparing a paint containing aggregated particle dispersion in which aluminum-containing silica nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface are aggregated.

[0179] (Comparative Example 6) Preparation of a paint containing a dispersion of aluminum-containing silica nanoparticles A paint containing a dispersion of aluminum-containing silica nanoparticles was prepared by adjusting the aluminum-containing silica nanoparticle dispersion from Reference Example 4 so that the final concentration was 0.9 wt% and the final concentration of the polyurethane aqueous dispersion as a binder resin was 0.1 wt%.

[0180] (Example 6) Application of a paint containing aggregated particle dispersion, in which aluminum-containing silica nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface are aggregated, to a solid surface. 200 μL of the paint containing the aggregated particle dispersion prepared in Example 5 was dropped onto a 5 cm x 5 cm polypropylene (PP) plate and spread onto the PP plate using a cone-large rod. The plate was air-dried to form a coating film on the PP plate.

[0181] (Comparative Example 7) Application of paint containing aluminum-containing silica nanoparticle dispersion to a solid surface 200 μL of paint containing the aluminum-containing silica nanoparticle dispersion prepared in Comparative Example 6 was dropped onto a 5 cm x 5 cm polypropylene (PP) plate and spread onto the PP plate using a cone-large rod. The plate was air-dried to form a coating film on the PP plate.

[0182] (Example 7) Virus Inactivation Test The antiviral performance of PP boards with the coated surfaces prepared in Example 6 and Comparative Example 7 was evaluated according to the ISO 21702 method. The PP boards were placed in a humidified petri dish. 0.4 mL of virus solution (feline calicivirus, Feline calicivirus, F-9, ATCC, VR-782, norovirus substitute)) was dropped onto the PP boards, and a 4 cm x 4 cm film (made of PP) was placed on top, and the mixture was allowed to react for 24 hours. After that, SCDLP was added as a stopping solution to stop the action against the virus, and the virus on the PP boards was washed off and recovered. This recovered solution was used as the stock solution for viral titer measurement, and a dilution series was prepared in minimal culture medium, and the infectivity titer was measured by the plaque method.

[0183] The difference between the common logarithm of the viral infectivity titer when tested using the PP board of Example 6 and the PP board without ceria nanoparticles (negative control) of Comparative Example 7, and the common logarithm of the viral infectivity titer when tested using the PP board without a coating surface (blank), was used as a virus inactivation index to evaluate antiviral performance. A larger virus inactivation index indicates higher antiviral performance. Specifically, a logarithmic reduction in infectivity titer (virus inactivation index) of 2.0 or higher was judged to indicate effective antiviral performance.

[0184] The evaluation results are shown in Table 4. The PP board with an antiviral surface prepared in Example 6 showed high antiviral activity. On the other hand, the PP board prepared in Comparative Example 7 showed low antiviral activity.

[0185]

[0186] (Reference Example 7) Preparation of a dispersion of ceria nanoparticles stabilized with nitric acid 500 mL of water was adjusted to pH 8.0 with sodium hydroxide. 1 g of cerium(III) nitrate hexahydrate was added. 10 mL of 1.2% hydrogen peroxide solution was added dropwise to obtain a pale orange aqueous solution. 1 M nitric acid was added to adjust the pH to 2.0, and the reaction solution was purified using an ultrafiltration membrane with a molecular weight cutoff of 10 kD to obtain a dispersion of cerium oxide nanoparticles stabilized with nitric acid (pale orange). This dispersion was transferred to a pressure vessel and subjected to hydrothermal treatment at 120°C (199 kPa) for 20 minutes to obtain a dispersion of ceria nanoparticles stabilized with nitric acid. The obtained dispersion was transparent. The average particle size (cumulant diameter) of the hydrodynamic diameter was 34.4 nm.

[0187] (Reference Example 8) Preparation of a dispersion of ceria nanoparticles stabilized with acetic acid 2.0 g of sodium acetate was dissolved in 500 mL of water and the pH was adjusted to 8.2. 1 g of cerium(III) acetate monohydrate was added. 10 mL of 1.2% hydrogen peroxide solution was added dropwise to obtain a pale orange aqueous solution. 1 M acetic acid was added to adjust the pH to 2.8, and the reaction solution was purified using an ultrafiltration membrane with a molecular weight cutoff of 10 kD to obtain a dispersion of cerium oxide nanoparticles stabilized with acetic acid (pale orange). This dispersion was transferred to a pressure vessel and subjected to hydrothermal treatment at 120°C (199 kPa) for 20 minutes to obtain a dispersion of ceria nanoparticles stabilized with acetic acid. The obtained dispersion was transparent. The average particle size (cumulant diameter) of the hydrodynamic diameter was 42.4 nm.

[0188] (Reference Example 9) Preparation of a dispersion of ceria nanoparticles stabilized with phthalic acid 2.4 g of phthalic acid was dissolved in 500 mL of water and the pH was adjusted to 8.0 with sodium hydroxide. 1 g of cerium(III) nitrate hexahydrate was added. 10 mL of 1.2% hydrogen peroxide solution was added dropwise to obtain a pale orange aqueous solution. 1 M nitric acid was added to adjust the pH to 2.8, and the reaction solution was purified using an ultrafiltration membrane with a molecular weight cutoff of 10 kD to obtain a dispersion of cerium oxide nanoparticles stabilized with phthalic acid (pale orange). This dispersion was transferred to a pressure vessel and subjected to hydrothermal treatment at 120°C (199 kPa) for 20 minutes to obtain a dispersion of ceria nanoparticles stabilized with nitric acid. The obtained dispersion was transparent. The average particle size (cumulant diameter) of the hydrodynamic diameter was 46.4 nm.

[0189] (Reference Example 10) Titania Nanoparticle Dispersion: The titania nanoparticle dispersion used was OT-RA305W7-20 manufactured by Nissan Chemical Industries, Ltd. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 46.4 nm.

[0190] (Reference Example 11) Zirconia Nanoparticle Dispersion: OZ-S20H manufactured by Nissan Chemical Industries, Ltd. was used as the zirconia nanoparticle dispersion. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 58.2 nm.

[0191] (Reference Example 12) Chromium Oxide Nanoparticle Dispersion: The chromium oxide nanoparticle dispersion was prepared by dispersing chromium(III) oxide nanopowder manufactured by Sigma-Aldrich Japan LLC in water, and using the supernatant portion after removing the precipitate. The average particle size (cumulant diameter) of the hydrodynamic diameter was 58.4 nm.

[0192] (Reference Example 13) Alumina Nanoparticle Dispersion: AS-520-A manufactured by Nissan Chemical Industries, Ltd. was used as the alumina nanoparticle dispersion. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 48.7 nm.

[0193] (Reference Example 14) Tungsten Oxide Nanoparticle Dispersion The lead oxide nanoparticle dispersion with a specific gravity of 7.0 or higher used in Comparative Example 9 was prepared by dispersing tungsten trioxide nanoparticles manufactured by Rare Metal Materials Research Institute Co., Ltd. in water, and using the supernatant portion after removing the precipitate. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 60.0 nm.

[0194] (Example 8) Preparation of aggregated particle dispersion of aluminum-containing silica nanoparticles and ceria nanoparticles with nitric acid adsorbed on their surface. The dispersion of ceria nanoparticles with nitric acid adsorbed on their surface, prepared in Reference Example 7, was mixed with the dispersion of aluminum-containing silica nanoparticles (Snowtex AK), prepared in Reference Example 4, to a final particle concentration of 2.2 wt%, so that the final particle concentration was 2.5 wt%. The aggregated particle dispersion described in the title was obtained. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 58.4 nm. The pH was 2.2. The pH was increased to 7.2 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 5.

[0195] (Example 9) Preparation of aggregated particle dispersion in which aluminum-containing silica nanoparticles and ceria nanoparticles with acetic acid adsorbed on their surface are aggregated. The dispersion of ceria nanoparticles with acetic acid adsorbed on their surface, prepared in Reference Example 8, was mixed with the dispersion of aluminum-containing silica nanoparticles (Snowtex AK), prepared in Reference Example 4, to a final particle concentration of 2.2 wt%, so that the final particle concentration was 2.5 wt%. The aggregated particle dispersion described in the title was obtained. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 64.6 nm. The pH was 3.1. The pH was increased to 7.4 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 5.

[0196] (Example 10) Production of aggregated particle dispersion of aluminum-containing silica nanoparticles and ceria nanoparticles with phthalic acid adsorbed on their surface A dispersion of ceria nanoparticles with phthalic acid adsorbed on their surface, produced in Reference Example 9, was mixed with a dispersion of aluminum-containing silica nanoparticles (Snowtex AK), produced in Reference Example 4, to a final particle concentration of 2.2 wt%, so that the dispersion had a final particle concentration of 2.5 wt%. The aggregated particle dispersion described in the title was obtained. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 67.4 nm. The pH was 3.0. The pH was increased to 7.2 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 5.

[0197] (Example 11) Preparation of aggregated particle dispersion of titania nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface. The dispersion of ceria nanoparticles with boric acid adsorbed on their surface, prepared in Reference Example 1, was mixed with the dispersion of titania nanoparticles (OT-RA305W7-20) prepared in Reference Example 10, to a final particle concentration of 2.2 wt%, to obtain the aggregated particle dispersion described in the title. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 58.0 nm. The pH was 2.7. The pH was increased to 7.6 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 5.

[0198] (Example 12) Preparation of aggregated particle dispersion of zirconia nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface. The dispersion of ceria nanoparticles with boric acid adsorbed on their surface, prepared in Reference Example 1, was mixed with the dispersion of zirconia nanoparticles (OZ-S20H) prepared in Reference Example 11, to a final particle concentration of 2.2 wt%, to obtain the aggregated particle dispersion described in the title. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 68.0 nm. The pH was 2.6. The pH was increased to 7.1 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 5.

[0199] (Example 13) Preparation of aggregated particle dispersion of chromium oxide nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface. The dispersion of ceria nanoparticles with boric acid adsorbed on their surface, prepared in Reference Example 1, was mixed with the dispersion of chromium oxide nanoparticles (chromium(III) oxide nanopowder) prepared in Reference Example 12, to a final particle concentration of 2.2 wt%, to obtain the aggregated particle dispersion described in the title. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 67.3 nm. The pH was 2.6. The pH was increased to 7.0 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 5.

[0200] (Example 14) Production of aggregated particle dispersion in which alumina nanoparticles and ceria nanoparticles with boric acid adsorbed on their surface were prepared. The dispersion of ceria nanoparticles with boric acid adsorbed on their surface, prepared in Reference Example 1, was mixed with the dispersion of alumina nanoparticles (AS-520-A) prepared in Reference Example 13, to a final particle concentration of 2.2 wt%, to obtain the aggregated particle dispersion described in the title. The average particle diameter (cumulant diameter) of the hydrodynamic diameter was 54.5 nm. The pH was 2.8. The pH was increased to 7.2 by adding a 0.01 M sodium hydroxide aqueous solution, but no aggregation occurred. The results are shown in Table 5.

[0201] (Comparative Example 8) Instead of metal oxide a nanoparticles, a dispersion of aggregated particles was prepared in which tungsten oxide nanoparticles with a specific gravity greater than 7.0 and ceria nanoparticles with boric acid adsorbed on their surface were aggregated. The dispersion of ceria nanoparticles with boric acid adsorbed on their surface, prepared in Reference Example 1, was mixed with the dispersion of tungsten oxide nanoparticles (tungsten trioxide nanoparticles), prepared in Reference Example 14, to a final particle concentration of 2.5 wt%, to a final particle concentration of 2.2 wt%, to obtain the mixed solution described in the title. The pH was 2.8. When the pH was increased by adding a 0.01 M sodium hydroxide aqueous solution, aggregation occurred. At this time, the pH was 7.1. The results are shown in Table 5.

[0202]

[0203] (Example 15) Preparation of a paint containing aggregated particle dispersion A paint containing aggregated particle dispersion was prepared by adjusting the aggregated particle dispersion prepared in Examples 8 to 14 to a final concentration of 1.9 wt% and the polyurethane aqueous dispersion as a binder resin to a final concentration of 0.1 wt%.

[0204] (Comparative Example 9) Preparation of a paint containing a dispersion of metal oxide a nanoparticles A paint containing a dispersion of aluminum-containing silica nanoparticles was prepared by adjusting the metal oxide a nanoparticle dispersion from Reference Examples 10 to 13 so that the final concentration was 0.9 wt% and the final concentration of the polyurethane aqueous dispersion as a binder resin was 0.1 wt%.

[0205] (Example 16) Application of paint containing aggregated particle dispersion to a solid surface 200 μL of paint containing the aggregated particle dispersion prepared in Example 15 was dropped onto a 5 cm x 5 cm polypropylene (PP) plate and spread onto the PP plate using a cone-large rod. It was air-dried to form a coating film on the PP plate.

[0206] (Comparative Example 10) Application of paint containing metal oxide a nanoparticle dispersion to a solid surface 200 μL of paint containing the metal oxide a nanoparticle dispersion prepared in Comparative Example 9 was dropped onto a 5 cm x 5 cm polypropylene (PP) plate and spread onto the PP plate using a cone-large rod. The paint was air-dried to form a coating on the PP plate. (Example 17) Virus inactivation test The antiviral performance of the PP plate having the coating surface prepared in Example 16 and Comparative Example 10 was evaluated according to the ISO 21702 method. The PP plate was placed in a humidified petri dish. 0.4 mL of virus solution (feline calicivirus, Feline calicivirus, F-9, ATCC, VR-782, norovirus substitute)) was dropped onto the PP plate and left to stand for 24 hours with a 4 cm x 4 cm film (made of PP) placed on top. Subsequently, SCDLP was added as a stopping agent to halt its action against the virus, and the virus on the PP plate was washed out and recovered. This recovered solution was used as the stock solution for viral titer measurement, and a dilution series was prepared in minimal culture medium. The infectivity titer was then measured using the plaque assay method.

[0207] The difference between the common logarithm of the viral infectivity titer when tested using the PP board of Example 16 and the PP board without ceria nanoparticles (negative control) of Comparative Example 10, and the common logarithm of the viral infectivity titer when tested using the PP board without a coating surface (blank), was used as the viral inactivation index to evaluate antiviral performance. A larger viral inactivation index indicates higher antiviral performance. Specifically, a logarithmic reduction in infectivity titer (viral inactivation index) of 2.0 or higher was judged to indicate effective antiviral performance.

[0208] The evaluation results are shown in Table 6. The PP board with an antiviral surface prepared in Example 16 showed high antiviral activity. On the other hand, the PP board prepared in Comparative Example 10 showed low antiviral activity.

[0209]

[0210] (Example 18) Anti-allergenicity test A phosphate buffer (pH 7.4) containing 0.05% Tween® 20 (polyoxyethylene sorbitan monolaurate) as a surfactant was used to prepare a test solution with an allergen concentration of 20 ng / ml by adding purified cedar pollen antigen Cry j1 (Biodynamics Research Institute Co., Ltd.). Next, 0.4 ml of this test solution was dropped onto the surface to be measured of a PP board having a coated surface prepared in Example 6 and Comparative Example 7, and a 4 cm x 4 cm film (made of PP) was placed on top and allowed to react for 24 hours. After the reaction, the test solution was collected and the allergen concentration of Cry j1 was quantified using an ELISA kit (Biodynamics Research Institute Co., Ltd.).

[0211] The allergen concentration when tested using a PP board without a coating surface (blank) was used as a baseline. The reduction rate of the allergen concentration when tested using the PP board of Example 6 and the PP board without ceria nanoparticles (negative control) of Comparative Example 7 was used as an indicator of anti-allergen performance. A larger reduction rate indicates higher anti-allergen performance. Specifically, a reduction rate of 70% or more in allergen concentration was judged to be effective anti-allergen performance.

[0212] The evaluation results are shown in Table 7. The PP board with anti-allergen properties prepared in Example 6 showed higher anti-allergen performance compared to the PP board prepared in Comparative Example 7.

[0213]

[0214] 1. Silica nanoparticles 2. Ceria nanoparticles

Claims

1. An aggregate particle comprising: (A) nanoparticles of a metal oxide, wherein the metal oxide has a specific gravity of 7.0 or less; and (B) ceria nanoparticles on which a boron compound, heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on its surface.

2. The aggregate particle according to claim 1, wherein the metal oxide nanoparticles are titania nanoparticles, zirconia nanoparticles, chromium oxide nanoparticles, alumina nanoparticles, silica nanoparticles having amino groups on their surface, or silica nanoparticles containing an aluminum compound.

3. The aggregate particle according to claim 2, wherein the silica nanoparticles having amino groups on their surface are silica nanoparticles in which the oxygen atoms on the surface of the silica nanoparticles are aminoalkylsilylated.

4. The aggregated particle according to claim 3, wherein the aminoalkyl group is an aminomethyl group, a 2-aminoethyl group, a 3-aminopropyl group, or an aminobutyl group.

5. The aggregate particle according to claim 1, wherein the boron compound is a boron compound represented by the following general formula (I). ｎ (OR') ３－ｎ ... (I) [(In general formula (I), n is an integer from 0 to 2, R represents an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a tolyl group, and R' represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a tolyl group. If there are multiple R or R', they may be the same or different.] 6. The aggregate particle according to claim 1, wherein the heterocyclic amine is a compound having one or more skeletons selected from the group consisting of a pyrazole skeleton, an imidazole skeleton, a triazole skeleton, a pyridine skeleton, a pyridazine skeleton, a pyrimidine skeleton, a pyrazine skeleton, a triazine skeleton, a tetrazine skeleton, an indazole skeleton, a benzimidazole skeleton, an azaindole skeleton, a pyrazolopyrimidine skeleton, a purine skeleton, a benzotriazole skeleton, a quinoxaline skeleton, a sinnoline skeleton, a quinazoline skeleton, a phthalazine skeleton, a naphthyridine skeleton, and a pteridine skeleton.

7. A dispersion of aggregated particles, wherein the aggregated particles described in any one of claims 1 to 6 are dispersed.

8. The aggregated particle dispersion according to claim 7, which has antiviral properties.

9. The aggregate particle dispersion according to claim 7, which has anti-allergenic properties.

10. A method for producing aggregated particle dispersion, comprising the step of mixing a dispersion of metal oxide nanoparticles having a specific gravity of 7.0 or less with a dispersion of ceria nanoparticles on which a boron compound, heterocyclic amine, nitric acid, acetic acid, or phthalic acid is adsorbed on its surface.

11. The method for producing a aggregate particle dispersion according to claim 10, wherein the metal oxide nanoparticles are titania nanoparticles, zirconia nanoparticles, chromium oxide nanoparticles, alumina nanoparticles, silica nanoparticles having amino groups on their surface, or silica nanoparticles containing an aluminum compound.

12. The manufacturing method according to claim 10, wherein the dispersion of ceria nanoparticles is produced by adding an oxidizing agent to a solution containing a boron compound, a heterocyclic amine, nitric acid, acetic acid, or phthalic acid and a cerium(III) salt.

13. The manufacturing method according to claim 12, wherein the oxidizing agent is hypochlorous acid, permanganate, chromic acid, dichromate, hydrogen peroxide, oxygen and / or ozone.

14. A paint containing aggregated particles, comprising aggregated particles according to any one of claims 1 to 6, or a dispersion in which such aggregated particles are dispersed.

15. A method for forming an antiviral surface by applying the aggregate particle dispersion described in claim 7, or an aggregate particle-containing paint containing the aggregate particle dispersion, to a solid surface.

16. The method for forming according to claim 15, wherein the antiviral activity value of the antiviral surface according to ISO 21702 is 2.0 or higher.

17. A method for forming an anti-allergen surface by applying the aggregate particle dispersion described in claim 7, or an aggregate particle-containing paint containing the aggregate particle dispersion, to a solid surface.

18. The method for forming according to claim 17, wherein the anti-allergen activity value of the anti-allergen surface is 70% or more when measured by the following steps 1 to 3. Step 1: A supply step in which a test solution containing an allergen is supplied to the surface to be measured on the anti-allergenic surface. Step 2: A reaction step in which a covering film is placed over the surface to be measured on the anti-allergenic surface to which the test solution has been supplied, and the allergen in the test solution is reacted with the anti-allergen agent on the surface to be measured on the anti-allergenic surface while the test solution is spread between the covering film and the surface to be measured. Step 3: A measurement step in which the test solution after the reaction is collected and the anti-allergen activity value is measured by enzyme immunoassay (ELISA).

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