Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N59/00—Biocides, pest repellants or attractants, or plant growth regulators containing elements or inorganic compounds
  • A01N59/16—Heavy metals; Compounds thereof
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01P—BIOCIDAL, PEST REPELLANT, PEST ATTRACTANT OR PLANT GROWTH REGULATORY ACTIVITY OF CHEMICAL COMPOUNDS OR PREPARATIONS
  • A01P1/00—Disinfectants; Antimicrobial compounds or mixtures thereof

Definitions

• the present invention relates to an antiviral composition containing specific silver nanoparticles as an active ingredient, and a member having the composition on its surface, and more specifically, the present invention relates to an antiviral composition that exhibits antiviral properties in the dark and is irradiated with light.
• the present invention relates to a highly transparent antiviral composition that further improves antiviral properties, and to a member having the composition on its surface.
• composition having antiviral properties can be formed on the surfaces of various members, it will be possible to apply it to a wide range of areas, so there is a need for a technology that imparts antiviral properties to members.
• the object to be imparted with antiviral properties is a member that requires visibility, such as an operation touch panel, or a member with design, it is desirable that the antiviral composition formed on its surface has excellent transparency. .
• Photocatalytic materials are attracting attention because they have a wide range of effects on cleaning the surface of substrates, such as antivirus and deodorizing properties, through photocatalytic reactions that occur when irradiated with light such as sunlight or artificial lighting.
• a photocatalytic reaction is a reaction caused by excited electrons and holes generated when a photocatalyst, typically titanium oxide, absorbs light. Excited electrons and holes generated on the titanium oxide surface by the photocatalytic reaction undergo a redox reaction with oxygen and water adsorbed on the titanium oxide surface to generate active species. Since microorganisms, viruses, odors, and dirt made of organic substances are decomposed by these active species, it is thought that the above-mentioned effect of cleaning the substrate surface can be obtained.
• Photocatalytic reactions are caused by irradiation with light in the ultraviolet region (wavelength 10 to 400 nm) or light in the visible region (wavelength 400 to 800 nm), so in principle, the effect will decrease in a dark place without natural light or artificial lighting. cannot be obtained.
• ultraviolet region wavelength 10 to 400 nm
• visible region wavelength 400 to 800 nm
• viruses that adhere to the surface of objects maintain their infectivity for several hours to several days, making it difficult for products that require sustained performance, such as antiviral products, to maintain their infectivity for several hours to several days.
• Patent Document 1 It is known that copper monoxide compounds such as cuprous oxide have antiviral properties (Patent Document 1).
• monovalent copper is easily oxidized to divalent copper by air or water, and there is a problem in that the high antiviral properties of monovalent copper cannot be maintained.
• Patent Document 2 discloses an antibacterial agent that utilizes the antibacterial effect of silver ions.
• Patent Document 1 discloses an antibacterial agent that utilizes the antibacterial effect of silver ions.
• Non-Patent Document 2 discloses an antibacterial agent that utilizes the antibacterial effect of silver ions.
• Non-Patent Document 2 discloses an antibacterial agent that utilizes the antibacterial effect of silver ions.
• silver is said to have low antiviral properties against non-enveloped viruses.
• Non-Patent Document 1 Silver is said to have low antiviral properties against non-enveloped viruses.
• Patent Document 3 reports that metal particles containing silver particles and platinum particles exhibit antiviral properties against non-enveloped viruses. However, it is stated that silver particles alone cannot inactivate viruses such as adenovirus. Further, Patent Document 3 evaluates the antiviral properties of an antiviral agent dispersion, but does not mention the imparting of antiviral properties to a member or the effect of light irradiation.
• Patent Document 4 The antiviral properties of molybdenum oxide and zinc oxide have been reported (Patent Document 4, Patent Document 5).
• Patent Document 5 The antiviral properties of molybdenum oxide and zinc oxide have been reported (Patent Document 4, Patent Document 5).
• these metal oxides tend to aggregate, making it difficult to obtain a composition with the transparency required for practical use.
• an object of the present invention is to provide an antiviral composition that exhibits antiviral properties and can form a highly transparent composition on the surface of a member.
• an antiviral composition containing the specific silver nanoparticles described below can achieve the above object, and completed the present invention.
• the present invention provides the following antiviral composition and a member having the composition on its surface.
• An antiviral composition containing as an active ingredient silver nanoparticles with a dispersed particle size of 1000 nm or less and a primary particle size of 500 nm or less, on the surface of which a protective agent is adsorbed, An antiviral composition having an antiviral activity value in the dark specified in JIS R1756:2020 that is greater than 0.3, and an antiviral activity value when exposed to light as specified in JIS R1756:2020 is a positive value.
• the antiviral composition according to [1] wherein the amount of the protective agent to the metal component in the silver nanoparticles is in the range of 0.001 to 10 in mass ratio.
• the present invention it is possible to provide a highly transparent composition that exhibits high antiviral properties in the dark and whose antiviral properties are further improved by light irradiation.
• a member that has both antiviral properties and transparency By applying it to the surface of the member, it is possible to provide a member that has both antiviral properties and transparency.
• antiviral property is used to include the meaning of inactivating a virus (reducing the infectivity of the virus or inactivating it). Antiviral properties were measured using the "antiviral activity value" calculated in accordance with JIS R1756:2020 "Fine ceramics - Antiviral test method for visible light responsive photocatalytic materials - Method using bacteriophage Q ⁇ " Evaluation was made using the criteria described in the example. Viruses are broadly classified into viruses with an envelope (lipid double membrane) and viruses without an envelope, based on their structure, and bacteriophage Q ⁇ is a virus without an envelope. In general, non-enveloped viruses are said to have higher resistance to disinfectants, etc. than enveloped viruses, and test methods are well established and have high accuracy and reproducibility. Bacteriophage Q ⁇ was used to evaluate virality.
• the virus for which the antiviral composition of the present invention exhibits antiviral properties may be enveloped or not.
• Enveloped viruses include bacteriophage ⁇ 6, human influenza virus, avian influenza virus, rubella virus, herpes simplex virus, AIDS virus, dengue virus, Mimi virus, rabies virus, Ebola virus, Lassa virus, Empox virus, and SARS coronavirus. , MERS coronavirus, Ebola virus, Fucerovirus, West Nile virus, Zika virus, etc.
• non-enveloped viruses examples include bacteriophage Q ⁇ , adenovirus, norovirus, feline calicivirus, rotavirus, sapovirus, poliovirus, astrovirus, enterovirus, human papillomavirus, hepatitis E virus, tobacco mosaic virus, and the like.
• the silver nanoparticles contained in the antiviral composition of the present invention contain at least silver, and may contain other components.
• Components other than silver include, but are not limited to, copper, zinc, platinum, palladium, nickel, aluminum, titanium, cobalt, zirconium, molybdenum, tungsten, gold, antimony, tin, sodium, magnesium, silicon, phosphorus, and sulfur.
• potassium calcium, scandium, vanadium, chromium, manganese, iron, gallium, germanium, arsenic, selenium, yttrium, niobium, ruthenium, rhodium, indium, tellurium, barium, hafnium, tantalum, rhenium, osmium, iridium, mercury, thallium , lead, bismuth, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, thorium, etc., or a mixture or alloy of two or more thereof.
• metal components other than silver are preferable, and iron, palladium, gold, platinum, copper, zinc, tin, molybdenum, titanium, and tungsten are more preferable.
• the content is preferably 0.01 to 49% by mass, and 0.1 to 40% by mass based on the mass of the metal component in the silver nanoparticles. % is more preferable, and 1 to 30% by mass is even more preferable. This is because if the content of metal components other than silver exceeds 50% by mass with respect to the mass of the metal components in the silver nanoparticles, antiviral properties may not be sufficiently exhibited. Further, when the content of metal components other than silver is less than 0.01% by mass, it hardly affects the properties of silver nanoparticles such as antiviral properties and dispersion stability.
• the silver nanoparticles contained in the antiviral composition of the present invention have a protective agent adsorbed on their surfaces.
• the term "protective agent” refers to surfactants that have the property of gathering at the interface between two phases, and low-molecular metal ligands that interact strongly with metal particles, such as alkylthiols, amine groups, silane groups, and phosphine groups. This refers to compounds with a large number of adsorption segments and polymers that easily adsorb to the particle surface. When these substances adsorb and coordinate on the surface of silver nanoparticles, electrostatic repulsion and steric repulsion occur between silver nanoparticles.
• the protective agent include surfactants such as anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants; polyvinylpyrrolidone, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, Water-soluble polymer compounds such as polyacrylic acid and methylcellulose; Amino acids such as cysteine, arginine, asparagine, and aspartic acid; Aliphatic amine compounds such as ethanolamine, diethanolamine, triethanolamine, and propanolamine; Tannic acid, gallocatechin, and gallic acid , pyrogallol, 4-benzylpyrogallol (2,3,4-trihydroxydiphenylmethane), ellagitannin and other polyphenols; butylamine, dibutylamine, hexylamine, cyclohexylamine, hepty
• surfactants such as anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric sur
• the protective agent may be one type of the above-mentioned compound or a combination of two or more types.
• the protective agent adsorbed on the surface of the silver nanoparticles preferably has a mass ratio of 0.001 to 10, more preferably 0.005 to 5, relative to the metal component in the silver nanoparticles. More preferably, the range is from 0.01 to 1.
• the dispersed particle diameter of the silver nanoparticles is such that the number-based 50% cumulative distribution diameter (D50) measured by a dynamic light scattering method using laser light is 1000 nm or less, preferably 1 to 1000 nm, and 1. It is more preferably 200 nm, and even more preferably 1 to 70 nm. Regarding the lower limit of the dispersed particle size, theoretically it is possible to use the smallest particle size that can have antiviral properties, but in practice it is preferably 1 nm or more. Further, if the dispersed particle diameter exceeds 1000 nm, it is not preferable because when an antiviral composition is prepared, not only the haze value may deteriorate but also the antiviral property may decrease.
• D50 cumulative distribution diameter measured by a dynamic light scattering method using laser light
• Examples of devices for measuring the dispersed particle size include ELSZ-2000ZS (manufactured by Otsuka Electronics Co., Ltd.), Nanotrack UPA-EX150 (manufactured by Nikkiso Co., Ltd.), and LA-910 (manufactured by Horiba Ltd.). etc. can be used.
• the primary particle diameter of the silver nanoparticles is 500 nm or less, preferably from 1 to 500 nm, more preferably from 1 to 100 nm, even more preferably from 1 to 50 nm.
• the lower limit of the primary particle diameter theoretically it is possible to use the smallest particle diameter that can have antiviral properties, but in practice it is preferably 1 nm or more.
• the primary particle diameter exceeds 500 nm, it is not preferable because when an antiviral composition is prepared, the composition not only becomes opaque but also has a reduced antiviral property.
• primary particle size means, unless otherwise specified, a particle size randomly selected from a plurality of particle images taken using a transmission electron microscope (for example, H-9500 manufactured by Hitachi High-Technologies, Ltd.). It refers to the arithmetic mean value of the projected area circle equivalent diameter (Heywood diameter) of about 1000 selected particles that do not overlap with each other.
• the content of silver nanoparticles in the antiviral composition is preferably 0.0001 to 100% by mass, more preferably 0.001 to 90% by mass.
• the antiviral composition may also contain additives such as a binder and a surfactant within a range that does not impair the effects of the present invention.
• the antiviral composition of the present invention includes an antiviral composition (silver nanoparticle dispersion) that further contains an aqueous dispersion medium in addition to the silver nanoparticles.
• an aqueous dispersion medium of the silver nanoparticle dispersion an aqueous solvent is usually used, and it is preferable to use water, a water-soluble organic solvent miscible with water, or a mixed solvent of water and a water-soluble organic solvent.
• water for example, deionized water, distilled water, pure water, etc. are preferable.
• water-soluble organic solvents examples include alcohols such as methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol, tert-butanol, ethylene glycol, diethylene glycol, polyethylene glycol, and ethylene glycol monomethyl.
• Glycol ethers such as ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol-n-propyl ether, acetone, ketones such as methyl ethyl ketone, 2-pyrrolidone , water-soluble nitrogen-containing compounds such as N-methylpyrrolidone, ethyl acetate, etc., and these may be used alone or in combination of two or more.
• the concentration of silver nanoparticles in the silver nanoparticle dispersion is not particularly limited, but generally the thinner the concentration, the better the dispersion stability, so it is preferably 0.0001 to 10% by mass, more preferably 0.001 to 5% by mass. , more preferably 0.01 to 1% by mass. If it is less than 0.0001% by mass, productivity will be extremely low, which is not preferable.
• the antiviral composition of the present invention exhibits high antiviral properties in the dark and has the characteristics that the antiviral properties are further improved by light irradiation. It is characterized by having an activity value greater than 0.3 and a positive antiviral activity value when irradiated with light as specified in JIS R1756:2020.
• the light that improves antiviral properties may include light with a wavelength that is absorbed by silver nanoparticles, and the wavelength is 200 to 800 nm, more preferably 300 to 700 nm. If it is less than 200 nm, the light itself may exhibit antiviral properties and is not practical, and if it exceeds 800 nm, it may be difficult to improve the antiviral properties by light irradiation.
• the light source may be anything that includes light of these wavelengths, such as fluorescent lamps, LEDs, incandescent lamps, low-pressure sodium lamps, high-pressure sodium lamps, metal halide lamps, mercury lamps, xenon lamps, organic EL lamps, krypton lamps, and halogen lamps.
• the light irradiation intensity is 5 to 100,000 lx, more preferably 10 to 50,000 lx. If it is less than 5 lx, the effect of light irradiation may not be confirmed, and conditions exceeding 100,000 lx are difficult to imagine in a real environment.
• a device for measuring illuminance for example, LX-105 (manufactured by Custom Co., Ltd.), CHF-LT1 (manufactured by Sanwa Supply Co., Ltd.), T-10A (manufactured by Konica Minolta Japan Co., Ltd.), etc. may be used. I can do it.
• the irradiation time is preferably about 1 minute to 48 hours.
• Examples of the method for producing the antiviral composition of the present invention, particularly the silver nanoparticle dispersion include a method comprising the following steps (1) to (3).
• step (1) two types of solutions are prepared: (1-1) a solution in which a raw material silver compound is dissolved in an aqueous dispersion medium, and (1-2) a solution in which a reducing agent and a protecting agent are dissolved in an aqueous dispersion medium.
• a solution of The reducing agent in the solution (1-2) has the effect of reducing the raw material silver compound in the solution (1-1).
• the protective agent in the solution (1-2) is added to the surface of the silver compound when the solution (1-1) and the solution (1-2) are mixed in the subsequent step (2) and the silver compound is reduced. has the effect of improving dispersion stability in the dispersion medium.
• These solutions may be produced by adding the raw material silver compound, reducing agent, and protective agent separately to an aqueous dispersion medium, and dissolving them by stirring.
• the stirring method is not particularly limited as long as it can be uniformly dissolved in the aqueous dispersion medium, and commonly available stirrers can be used.
• Various silver compounds can be used as the raw material silver compound, such as silver chloride; inorganic acid salts such as nitrates and sulfates; organic acids such as formic acid, citric acid, oxalic acid, lactic acid, and glycolic acid.
• Salt Complex salts such as ammine complexes, cyano complexes, halogeno complexes, and hydroxy complexes can be mentioned, and one or more of these may be used in combination.
• it is preferable to use inorganic acid salts such as silver chloride, nitrate, and sulfate.
• the content of the raw material silver compound is such that the concentration as Ag in the solution (1-1) containing the raw material silver compound is 0.5 to 200 mmol/L, preferably 5 to 100 mmol/L.
• the silver nanoparticles contain a component other than silver
• raw material compounds other than silver include zinc, platinum, palladium, nickel, aluminum, titanium, cobalt, zirconium, molybdenum, tungsten, gold, antimony, tin, sodium, magnesium, silicon, phosphorus, sulfur, potassium, Calcium, scandium, vanadium, chromium, manganese, iron, gallium, germanium, arsenic, selenium, yttrium, niobium, ruthenium, rhodium, indium, tellurium, barium, hafnium, tantalum, rhenium, osmium, iridium, mercury, thallium, lead, Inorganic acid salts such as chlorides, nitrates, and sulfates of bismuth, lanthanum, cerium, praseodymium
• aqueous dispersion medium in the solution (1-1) containing the raw material silver compound examples include those mentioned above as the aqueous dispersion medium for the silver nanoparticle dispersion, and the amount thereof is determined based on the raw material silver compound and silver. This is the remainder of the content of the raw material compounds of the components other than .
• the reducing agent is not particularly limited, but any of various reducing agents capable of reducing silver ions constituting the raw material silver compound can be used.
• hydrazines such as hydrazine, hydrazine monohydrate, phenylhydrazine, and hydrazinium sulfate
• amines such as dimethylaminoethanol, triethylamine, octylamine, dimethylaminoborane, and benzotriazole
• oxalic acid citric acid, ascorbic acid, and tartaric acid.
• organic acids such as malic acid, malonic acid, and formic acid
• polyphenols such as gallic acid, chlorogenic acid, catechin, cyanidin, epigallocatechin, delphinidin, tannic acid, and saponin
• aldehydes such as formaldehyde, acetaldehyde, and glycolaldehyde
• hydrides such as zinc borohydride, sodium acetoxyborohydride
• pyrrolidones such as polyvinylpyrrolidone (PVP), 1-vinylpyrrolidone, N-vinylpyrrolidone, methylpyrrolidone
• glucose galactose,
• hydrazines such as hydrazine monohydrate, organic acid salts such as sodium citrate, and gallic acid have excellent silver ion reduction ability and have small molecular weights and can be easily filtered out in the washing process of silver nanoparticles with aqueous solvents.
• polyphenols such as tannic acid, hydrides such as sodium borohydride, and aldehydes such as formaldehyde and glycolaldehyde are particularly preferred.
• the aqueous dispersion medium for dissolving the reducing agent the same aqueous dispersion medium as used for the above metal compound can be used.
• the content of the reducing agent can be 0.001 to 50% by mass, preferably 0.01 to 40% by mass, based on the total mass of the solution (1-2) containing the reducing agent and the protective agent. This is because when the content of the reducing agent exceeds 50% by mass, the content of the protective agent and aqueous solvent becomes relatively small, and a sufficient amount of the protective agent cannot be adsorbed on the surface of the silver nanoparticles, resulting in high dispersion stability. Silver nanoparticles may not be formed, and if the reducing agent content is less than 0.001% by mass, it is necessary to add a large amount of a solution containing a reducing agent and a protective agent to the solution containing the raw material silver compound. This is because it is not practical.
• the protective agent is not particularly limited, but any of various protective agents that can be adsorbed onto the surface of the reduced raw material silver compound and improve the dispersion stability in the aqueous dispersion medium can be used.
• surfactants such as anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants
• PVP polyethylene glycol, polyvinyl alcohol, polyethylene imine, polyethylene oxide, polyacrylic acid , water-soluble polymer compounds such as methylcellulose
• amino acids such as cysteine, arginine, asparagine, and aspartic acid
• aliphatic amine compounds such as ethanolamine, diethanolamine, triethanolamine, and propanolamine
• tannic acid gallocatechin, gallic acid, pyrogallol
• Polyphenols such as 4-benzylpyrogallol (2,3,4-trihydroxydiphenylmethane) and ellagitannin; butylamine, dibutylamine, he
• organic acid salts such as sodium citrate, polyphenols such as gallic acid and tannic acid, and oleic acid, which have excellent stability of silver nanoparticles and have a small molecular weight and can be easily filtered out in the washing process of silver nanoparticles with aqueous solvents.
• carboxylic acid compounds such as sodium chloride.
• the combination is not particularly limited, but for example, in addition to PVP and sodium citrate, which have excellent dispersion stability for silver nanoparticles, using sodium silicate, gelatin, an aliphatic amine compound, hindered amine, etc. as a protective agent at the same time will improve durability.
• the content of the protective agent is preferably 0.001 to 60% by mass, more preferably 0.01 to 50% by mass, based on the total mass of the solution (1-2) containing the reducing agent and the protective agent. This is because when the content of the protective agent exceeds 60% by mass, the content of the reducing agent and the aqueous solvent becomes relatively small, which may deteriorate the yield of silver nanoparticles and also cause the subsequent dispersion of silver nanoparticles.
• the process of washing the liquid with an aqueous solvent requires a large amount of aqueous solvent, which is impractical, and if the content of the protective agent is less than 0.001% by mass, a sufficient amount of the protective agent may not be on the surface of the silver nanoparticles. This is because silver nanoparticles with high dispersion stability may not be formed because they cannot be adsorbed.
• aqueous dispersion medium (aqueous solvent) for the solution (1-2) containing a reducing agent and a protecting agent it is preferable to use water, a water-soluble organic solvent miscible with water, or a mixed solvent of water and a water-soluble organic solvent.
• water for example, deionized water, distilled water, pure water, etc. are preferable.
• water-soluble organic solvents include alcohols such as methanol, ethanol, isopropanol, n-propanol, 2-propanol, n-butanol, 2-butanol, tert-butanol, ethylene glycol, and diethylene glycol; ethylene glycol monomethyl ether; , glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol-n-propyl ether; ketones such as acetone and methyl ethyl ketone; 2-pyrrolidone, Examples include water-soluble nitrogen-containing compounds such as N-methylpyrrolidone; ethyl acetate; water-soluble organic solvents may be used alone or in combination of two or more thereof.
• alcohols such as methanol, ethanol, isopropanol,
• the content of the aqueous solvent can be 1 to 99.99% by mass, preferably 1 to 99.9% by mass, based on the total mass of the solution (1-2) containing the reducing agent and the protecting agent. This is not practical when the content of the aqueous solvent exceeds 99.99% by mass, as it is necessary to add a large amount of a solution containing a reducing agent and a protective agent to the solution containing the raw material silver compound. This is because if the content is less than 1% by mass, the effect of improving the fluidity of the solution containing the reducing agent and the protecting agent is small.
• a basic substance or an acidic substance may be added to the solution (1-2) containing a reducing agent and a protecting agent.
• Basic substances include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkali metal hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate; tert- Examples include alkali metal alkoxides such as butoxypotassium, sodium methoxide, and sodium ethoxide; alkali metal salts of aliphatic hydrocarbons such as butyl lithium; and amines such as triethylamine, diethylaminoethanol, and diethylamine.
• acidic substances include inorganic acids such as aqua regia, hydrochloric acid, nitric acid, and sulfuric acid; organic acids such as formic acid, acetic acid, chloroacetic acid, dichloroacetic acid, oxalic acid, trifluoroacetic acid, and trichloroacetic acid.
• the content of the basic substance or acidic substance can be 0 to 30% by mass, preferably 0 to 20% by mass, based on the total mass of the solution (1-2) containing the reducing agent and the protecting agent. The lower limit when blending is 0.0001% by mass.
• concentrations of these two solutions are not particularly limited, but in general, the lower the concentration, the smaller the primary particle size of each silver nanoparticle formed, so it depends on the target primary particle size range. It is preferable to set a suitable concentration range.
• the pH when these two solutions are mixed may be such that silver is reduced.
• the appropriate pH range varies depending on the reducing agent used, but for example, when using divalent iron, which undergoes a reduction reaction in an acidic aqueous solution, as the reducing agent, the pH when the two solutions are mixed is 0 to 0. It is preferable to adjust it so that it is within the range of 7. If the pH exceeds 7, the reduction reaction of silver may not proceed, and if it is less than 0, it is not preferable because the subsequent filtration step requires a lot of labor and productivity decreases.
• the pH of the two solutions should be adjusted to be within the range of 7 to 15. preferable. If the pH is less than 7, the reduction reaction of silver may not proceed, and if it exceeds 15, it is not preferable because the subsequent filtration step requires a lot of labor and productivity decreases.
• step (2) the solution prepared in step (1) in which the raw material silver compound is dissolved in an aqueous dispersion medium and the solution in which a reducing agent and a protective agent are dissolved in an aqueous dispersion medium are mixed, and silver nano Produce a particle dispersion.
• the method of mixing these two solutions is not particularly limited as long as the two solutions can be mixed uniformly, but for example, the silver compound solution and the reducing agent and protectant solution are placed in a reaction container and stirred.
• the temperature during mixing is not particularly limited, and is preferably adjusted to a suitable temperature depending on the molar ratio of silver and components other than silver in the target silver nanoparticles, primary particle diameter, reaction time, etc.
• step (3) the silver nanoparticle dispersion produced in step (2) is washed with an aqueous dispersion medium using a membrane filtration method.
• aqueous dispersion medium it is preferable to use water, a water-soluble organic solvent that is miscible with water, and a mixed solvent of water and a water-soluble organic solvent.
• water for example, deionized water, distilled water, pure water, etc. are preferable.
• water-soluble organic solvents include alcohols such as methanol, ethanol, isopropanol, n-propanol, 2-propanol, n-butanol, 2-butanol, tert-butanol, ethylene glycol, diethylene glycol, and ethylene glycol monomethyl ether.
• glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol-n-propyl ether, acetone, ketones such as methyl ethyl ketone, 2-pyrrolidone
• water-soluble nitrogen-containing compounds such as N-methylpyrrolidone, ethyl acetate, and the like, and the water-soluble organic solvent may be used alone or in combination of two or more thereof.
• non-volatile impurities other than silver nanoparticles such as components other than silver in raw material silver compounds, reducing agents, and protective agents not adsorbed to silver nanoparticles, are removed from the silver nanoparticle dispersion. ⁇ To separate. It is preferable to wash until the amount of the protective agent adsorbed on the surface of the silver nanoparticles becomes a mass ratio of 0.001 to 10 with respect to the total metal component in the silver nanoparticles in the silver nanoparticle dispersion. , 0.001 to 5, and even more preferably 0.001 to 1.
• the mass ratio is less than 0.001, the dispersion stability of the silver nanoparticles may decrease, and if it exceeds 10, the amount of protective agent adsorbed on the surface of the silver nanoparticles is large, resulting in poor antiviral properties. It may not be fully demonstrated.
• ICP-OES metal component concentration in silver nanoparticle dispersion
• the concentration of protective agent adsorbed on the surface of silver nanoparticles in silver nanoparticle dispersion is determined by Calculated from the mass of the nonvolatile content (metal component + protective agent adsorbed on the surface of silver nanoparticles) after sampling and heating at 105°C for 3 hours to volatilize the solvent and the mass of the sampled silver nanoparticle dispersion. It can be calculated by subtracting the metal component concentration determined by the above ICP-OES from the nonvolatile concentration.
• the membrane used in the membrane filtration method is not particularly limited as long as it can separate silver nanoparticles and non-volatile impurities other than silver nanoparticles from the silver nanoparticle dispersion.
• Examples include filtration membranes and nanofiltration membranes, and among these, a membrane having an appropriate pore size can be used.
• any method such as centrifugal filtration, pressure filtration, or cross-flow filtration can be adopted.
• any appropriate shape can be used, such as a hollow fiber type, spiral type, tubular type, or flat membrane type.
• the material of the filtration membrane is not particularly limited as long as it is durable against the silver nanoparticle dispersion, and examples include polyethylene, tetrafluoroethylene, polypropylene, cellulose acetate, polyacrylonitrile, polyimide, polysulfone, and polyethersulfone. It can be appropriately selected and used from organic films such as, inorganic films such as silica, alumina, zirconia, titania, etc.
• the above-mentioned filtration membranes include Microza (manufactured by Asahi Kasei Chemicals Co., Ltd.), Amicon Ultra (manufactured by Merck Millipore Co., Ltd.), MOLSEP (Daisen Membrane Systems Co., Ltd.), and Ultrafilter (manufactured by Merck Millipore Co., Ltd.).
• Microza manufactured by Asahi Kasei Chemicals Co., Ltd.
• Amicon Ultra manufactured by Merck Millipore Co., Ltd.
• MOLSEP Denst Configuration Membrane Systems Co., Ltd.
• Ultrafilter manufactured by Merck Millipore Co., Ltd.
• Examples include Advantech Toyo Co., Ltd.) and MEMBRALOX (Nippon Pole Co., Ltd.).
• step (3) when adding the above-mentioned optional additives, it is preferable to add them after the membrane filtration step of step (3) is completed.
• the silver nanoparticle dispersion can be used to form an antiviral composition on the surfaces of various members.
• the various members are not particularly limited, but examples of the material of the members include organic materials and inorganic materials. These can have various shapes depending on their respective purposes and uses.
• organic materials examples include vinyl chloride resin (PVC), polyethylene (PE), polypropylene (PP), polycarbonate (PC), acrylic resin, polyacetal, fluororesin, silicone resin, and ethylene-vinyl acetate copolymer (EVA).
• PVC vinyl chloride resin
• PE polyethylene
• PP polypropylene
• PC polycarbonate
• acrylic resin acrylic resin
• polyacetal polyacetal
• fluororesin silicone resin
• silicone resin ethylene-vinyl acetate copolymer
• EVA ethylene-vinyl acetate copolymer
• acrylonitrile-butadiene rubber NBR
• polyethylene terephthalate PET
• polyethylene naphthalate PEN
• polyvinyl butyral PVB
• ethylene-vinyl alcohol copolymer EVOH
• polyimide resin polyphenylene sulfide (PPS)
• polyether Synthetic resin materials such as imide (PEI), polyether ether imide (PEEI), polyether ether ketone (PEEK), melamine resin, phenol resin, acrylonitrile-butadiene-styrene (ABS) resin, natural materials such as natural rubber, or Semi-synthetic materials of the above-mentioned synthetic resin materials and natural materials can be mentioned.
• PPS polyphenylene sulfide
• inorganic materials include non-metallic inorganic materials and metallic inorganic materials.
• nonmetallic inorganic materials include glass, ceramics, and stone. These may be manufactured into various shapes such as tiles, glass, mirrors, walls, and decorative materials.
• the metal inorganic material include cast iron, steel, iron, iron alloy, aluminum, aluminum alloy, nickel, nickel alloy, zinc die casting, and the like. These may be plated with the above metal inorganic material, may be coated with the above organic material, or may be plated on the surface of the above organic material or non-metal inorganic material.
• a commonly used binder may be added as long as it does not impair the transparency of the antiviral composition.
• a silver nanoparticle dispersion is applied to the surface of the member using a known coating method such as spray coating or dip coating, followed by far infrared drying or IH.
• the silver nanoparticles may be dried by a known drying method such as drying or hot air drying, and the thickness of the dried silver nanoparticles can be selected in various ways, but is usually preferably in the range of 10 nm to 10 ⁇ m.
• the antiviral composition described above is formed on the surface of the member.
• the antiviral composition thus formed on the member is transparent (haze value is preferably 3% or less, more preferably 2.7% or less), exhibits antiviral properties in the dark, Furthermore, high antiviral activity can be obtained by light irradiation, and various members having the antiviral composition on the upper surface can exhibit antiviral properties on the surface.
• Antiviral test of silver nanoparticle composition Antiviral activity value was determined in accordance with JIS R1756:2020 "Fine ceramics - Antiviral test method for visible light responsive photocatalytic material - Method using bacteriophage Q ⁇ " was calculated, and the antiviral properties of the composition were evaluated using the following criteria.
• a 50 mm x 50 mm x 2 mm glass piece (hereinafter referred to as a test piece) was used as a member on which the composition was formed.
• ⁇ Measurement of antiviral properties based on JIS R1756:2020> A glass rod was placed in a moisturized petri dish, and a test piece was placed on top of the glass rod.
• bacteriophage solution 200 ⁇ L was placed on the test piece, the bacteriophage solution was covered with a cover film, and then the petri dish was covered with a moisturizing glass.
• the prepared petri dish was left standing for 4 hours in a dark place (0 lx) or a bright place (visible light from a white fluorescent lamp that cuts wavelengths of 380 nm or less: 500 lx).
• a digital illumination meter LX-105 manufactured by Custom Co., Ltd. was used to measure the illuminance. After standing still, the test piece and cover film were transferred to a sterilized stomach bag, washed out with 5 mL of physiological saline containing a surfactant, and the bacteriophage solution was collected.
• the collected bacteriophage solution was diluted, and 100 ⁇ L each of the solution and Escherichia coli solution were mixed, further mixed with a soft agar medium, and then plated on the medium.
• the infectious titer of the virus was determined by incubating at 37° C. overnight and counting the number of killed coliform bacteria (plaques).
• the antiviral activity value based on JIS R1756:2020 is obtained by performing the above operation using an antiviral-treated test piece and an untreated test piece, and finding it as the difference in the average value of the common logarithm of the infectious titer of both. It is a value.
• the light irradiation effect could be calculated from the antiviral activity value in the dark and the antiviral activity value in the light, and was evaluated based on the following criteria.
• Effect of light irradiation Antiviral activity value in the light of the test piece with antiviral processing - Antiviral activity value in the dark of the test piece with antiviral processing - High antiviral property and light irradiation effect (indicated by ⁇ ) - ⁇ The antiviral activity value of the antiviral-treated test piece in the light is 2.0 or more, and the effect of light irradiation is 0.3 or more ⁇ There is antiviral property and light irradiation effect (indicated by ⁇ ) ⁇ The antiviral activity value of the antiviral-treated test piece in a bright place is 0.3 or more, and the effect of light irradiation exceeds 0. ⁇ No effect of light irradiation (indicated by ⁇ )...The effect of light irradiation is 0 or less
• the haze value was measured using a haze meter (trade name "Digital Haze Meter NDH-200", manufactured by Nippon Denshoku Kogyo Co., Ltd.).
• the transparency of the silver nanoparticle composition was evaluated based on the following criteria based on the difference in the obtained haze values. ⁇ Very good (displayed as ⁇ )...difference is +3% or less ⁇ Good (displayed as ⁇ )...difference exceeds +3% but not more than +5% ⁇ Poor (displayed as ⁇ )...difference is +5 more than %
• Example 1 ⁇ Preparation of silver nanoparticle dispersion protected with sodium citrate> Using pure water as a solvent, silver nitrate was dissolved so that the concentration as Ag was 65.0 mmol/L to obtain a solution (I) containing a raw material silver compound.
• a solution (pH 4.6) obtained by mixing 1500 mL of solution (I) containing a reducing agent and a protecting agent at 25 °C with 300 mL of solution (I) containing a raw material silver compound at 25 °C in a reactor, A silver nanoparticle dispersion ( ⁇ ) was obtained by concentrating and washing with pure water using an ultrafiltration membrane with a molecular weight cutoff of 10,000 (MOLSEP, Daisen Membrane Systems, Inc.). A desktop pH meter F-71 (manufactured by Horiba Advanced Techno Co., Ltd.) was used to measure the pH.
• the metal concentration of the obtained silver nanoparticle dispersion was measured using ICP-OES (Agilent Technologies, Inc.), and the mass ratio of the protective agent to the metal component was calculated from the nonvolatile content concentration and the metal concentration. Furthermore, the obtained silver nanoparticle dispersion was diluted to a predetermined concentration, and the dispersed particle diameter was measured using ELSZ-2000ZS (manufactured by Otsuka Electronics Co., Ltd.). In addition, the obtained silver nanoparticle dispersion was photographed using a transmission electron microscope (H-9500 manufactured by Hitachi High-Technologies Co., Ltd.), and 1000 non-overlapping particles were randomly selected from multiple particle images.
• the projected area circle equivalent diameter (Heywood diameter) of the particles was measured, and the primary particle diameter of the silver nanoparticles was calculated from the arithmetic mean value.
• the composition and physical properties of the obtained silver nanoparticle dispersion are summarized in Table 1 below.
• Example 2 ⁇ Preparation of silver nanoparticle dispersion protected with tannic acid> Using pure water as a solvent, silver nitrate was dissolved so that the concentration of Ag was 6.0 mmol/L to obtain a solution (II) containing a raw material silver compound.
• a solution (pH 12.6) obtained by mixing 1000 mL of solution (II) containing a raw material silver compound at 90 ° C. with 100 mL of solution (ii) containing a reducing agent and a protecting agent at 60 ° C. in a reactor.
• An evaluation sample was prepared in the same manner as in Example 1, except that the silver nanoparticle composition (B) was obtained from the silver nanoparticle dispersion ( ⁇ ), and various evaluations were performed.
• Example 3 ⁇ Preparation of silver-iron nanoparticle dispersion protected with tannic acid and sodium oleate> Silver nitrate was dissolved in pure water so that the concentration as Ag was 6.0 mmol/L, and iron(II) nitrate nonahydrate was dissolved in pure water so that the concentration as Fe was 1.1 mmol/L to obtain a raw material silver compound. A solution (III) containing the following was obtained.
• a silver-iron nanoparticle dispersion ( ⁇ ) was obtained in the same manner as in Example 2 except that each was used. Note that the pH of the liquid before being concentrated using an ultrafiltration membrane and washed with pure water was 12.7. Further, the content of the silver component was 90% by mass with respect to the mass of the metal component of the silver-iron nanoparticles in the silver-iron nanoparticle dispersion ( ⁇ ), and the content of the iron component was 10% by mass.
• An evaluation sample was prepared in the same manner as in Example 1, except that the silver-iron nanoparticle composition (C) was obtained from the silver-iron nanoparticle dispersion ( ⁇ ), and various evaluations were performed.
• Example 4 ⁇ Preparation of polyvinylpyrrolidone-protected silver palladium nanoparticle dispersion> Contains a raw material silver compound in which pure water is used as a solvent and silver nitrate is dissolved so that the concentration as Ag is 6.0 mmol/L, and palladium nitrate dihydrate is dissolved so that the concentration as Pd is 0.1 mmol/L. A solution (IV) was obtained.
• a solution (iv) containing a reducing agent and a protecting agent was obtained by mixing 10% by mass of polyvinylpyrrolidone K30 (PVP, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) as a reducing agent/protecting agent.
• a silver-palladium nanoparticle dispersion ( ⁇ ) was obtained in the same manner as in Example 2, except that each was used. Note that the pH of the liquid before being concentrated using an ultrafiltration membrane and washed with pure water was 13.2. Further, the content of the silver component was 98% by mass with respect to the mass of the metal component of the silver-palladium nanoparticles in the silver-palladium nanoparticle dispersion ( ⁇ ), and the content of the palladium component was 2% by mass.
• An evaluation sample was prepared in the same manner as in Example 1, except that the silver nanoparticle composition (D) was obtained from the silver palladium nanoparticle dispersion ( ⁇ ), and various evaluations were performed.
• Example 5 ⁇ Preparation of polyvinylpyrrolidone-protected silver palladium nanoparticle dispersion> A silver palladium nanoparticle dispersion ( ⁇ ) was prepared in the same manner as in Example 4, except that the temperature of the solution containing the raw material silver compound was set at 25 °C, and the temperature of the solution containing the reducing agent and protective agent was set at 25 °C. Obtained. Note that the pH of the liquid before being concentrated using an ultrafiltration membrane and washed with pure water was 13.2.
• An evaluation sample was prepared in the same manner as in Example 1, except that the silver nanoparticle composition (E) was obtained from the silver-palladium nanoparticle dispersion ( ⁇ ), and various evaluations were performed.
• a solution (V) containing a raw material silver compound was used instead of the solution (I) containing a raw material silver compound, and a solution (v) containing a reducing agent was used instead of the solution (i) containing a reducing agent and a protective agent.
• a silver particle dispersion ( ⁇ ) was obtained in the same manner as in Example 1 except for the above. Note that the pH of the liquid before being concentrated using an ultrafiltration membrane and washed with pure water was 13.2.
• An evaluation sample was prepared in the same manner as in Example 1, except that the silver particle composition (F) was obtained from the silver particle dispersion ( ⁇ ), and various evaluations were performed.
• the dispersion particle size of the silver nanoparticles is 1000 nm or less, the primary particle size is 500 nm or less, and the mass of the protective agent adsorbed on the surface of the silver nanoparticles and the metal component in the silver nanoparticles is
• An antiviral composition formed from a silver nanoparticle dispersion with a ratio of 10 or less has excellent transparency, an antiviral activity value in the dark of 0.3 or more (inactivates about 50% of viruses), and The light irradiation effect (antiviral activity value by light irradiation) exceeded 0, confirming that the antiviral properties of the composition and the antiviral properties were improved by light irradiation.
• the antiviral activity value in the dark was 2.0 or more (approximately 99% of viruses were inactivated), and the light irradiation effect (antiviral activity value by light irradiation) was 0.3.
• the composition has high antiviral properties and that the antiviral properties are improved by light irradiation.
• Comparative Example 1 Although the composition containing coarse silver particles exhibits antiviral properties in the dark, no improvement in antiviral properties is observed upon irradiation with light. In addition, the composition had a high haze value and was opaque, which could impair the design of the member.

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