Copper metal fine particle powder and its manufacturing method

Abstract

To provide a metal copper fine particle powder that is capable of efficiently exhibiting anti-virus properties, and a method for producing the metal copper fine particle powder.SOLUTION: A metal copper fine particle powder comprises metal copper fine particles coated with fatty acids and / or ester compounds.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a metallic copper fine particle powder and a method for producing the same, and more particularly to a metallic copper fine particle powder capable of efficiently exhibiting antiviral properties and a method for producing the same. [Background technology]

[0002] Conventionally, silver ions or copper (II) ions have been used as active ingredients in materials having antibacterial or antiviral properties, and various antiviral materials have been proposed in which these metal ions are supported on substances such as zeolite or silica gel or dispersed in a solvent. However, although the above metal ions can exhibit antiviral activity against viruses having an envelope structure, such as influenza viruses, they are unable to exhibit antiviral activity against viruses that do not have an envelope structure, such as noroviruses.

[0003] Monovalent copper compounds are also known as metal compounds capable of exhibiting antiviral properties, regardless of the presence or absence of an envelope structure. For example, the following Patent Document 1 describes an antiviral composition that contains fine particles of a monovalent copper compound, a reducing agent, and a dispersion medium, and has a pH of 6 or less. The following Patent Document 2 describes an antiviral composition having a BET specific surface area of ​​5 to 100 m2. 2 The patent document 3 below describes an antibacterial and antiviral composition that contains cuprous oxide particles of 100000000 / g, a saccharide having an aldehyde group, and a photocatalytic substance. The patent document 3 below describes an antiviral coating film that contains a copper-supported oxide having an average secondary particle diameter of 80 nm to 600 nm, in which at least one of copper particles and copper compound particles is supported on an oxide particle, barium sulfate having an average secondary particle diameter of 1 μm to 15 μm, and a water-repellent resin binder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5194185 [Patent Document 2] JP 2013-82654 A [Patent Document 3] JP 2015-205998 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, fine particles of a monovalent copper compound tend to aggregate, making it difficult to uniformly disperse the monovalent copper compound. Thus, when the dispersion liquid is used as an antiviral composition or when it is mixed with a paint and used as a coated antiviral molded body, it has been difficult to efficiently express the antiviral properties of the fine particles of the monovalent copper compound. In addition, when a monovalent copper compound having a large particle size as described in the above patent document is used, the particle surface area is reduced, and the antiviral properties are reduced due to a decrease in the chance of contact with the virus. In addition, an antiviral molded body coated with a monovalent copper compound having a large particle size has a problem that the haze and light transmittance are deteriorated, resulting in a loss of transparency. Furthermore, fine particles of monovalent copper compounds can be obtained by pulverization, but since there is no coating agent or stabilizer, they tend to aggregate, and there are problems with this method, such as the tendency for cuprous oxide to oxidize to copper(II) oxide.

[0006] In order to solve these problems, the present inventors have conducted intensive research into microparticles that can efficiently exhibit high antiviral properties, and as a result, have found that metallic copper can exhibit higher antiviral properties than monovalent copper compounds, and that by coating the surface of metallic copper microparticles with a fatty acid and an ester compound of the fatty acid, the microparticles can be uniformly dispersed without aggregation even when contained in a low-boiling point solvent at a high concentration. However, although the above-mentioned metallic copper microparticles can be made into a uniform dispersion liquid without aggregation in the state of a dispersion liquid, the metallic copper microparticles alone without a medium are prone to aggregation, making it difficult to efficiently exhibit antiviral properties. In addition, there was a problem that the amount of organic matter (fatty acid and ester compound) coated per secondary particle of the metallic copper microparticles increases due to aggregation, making it impossible to obtain a fine particle powder having high antiviral properties as obtained in the dispersion liquid. Therefore, an object of the present invention is to provide a metallic copper fine particle powder capable of efficiently exhibiting antiviral properties, and a method for producing this metallic copper fine particle powder. [Means for solving the problem]

[0008] According to the first manufacturing method of the present invention, there is provided a method for manufacturing a metallic copper microparticle powder, which comprises the steps of: adding fatty acid copper to a polyol and heating and mixing the polyol to prepare a dispersion in which metallic copper microparticles coated with fatty acids and / or ester compounds of the fatty acids and polyol are dispersed; mixing the dispersion with a low-boiling point solvent, separating the polyol and the low-boiling point solvent into two phases, and transferring the free fatty acids and ester compounds in the polyol to the low-boiling point solvent; removing the low-boiling point solvent after the two-phase separation; and recovering the metallic copper microparticles coated with fatty acids and / or ester compounds in the polyol from which the low-boiling point solvent has been removed.

[0009] According to the second manufacturing method of the present invention, there is provided a method for manufacturing a metallic copper microparticle powder, which comprises the steps of: adding a fatty acid and a copper compound to a polyol, heating and mixing the resulting mixture to prepare a dispersion in which metallic copper microparticles coated with fatty acids and / or ester compounds of the fatty acids and polyol are dispersed; mixing the dispersion with a low-boiling point solvent, separating the polyol and the low-boiling point solvent into two phases, and transferring the free fatty acids and ester compounds in the polyol to the low-boiling point solvent; removing the low-boiling point solvent after the two-phase separation; and recovering the metallic copper microparticles coated with fatty acids and / or ester compounds in the polyol from which the low-boiling point solvent has been removed.

[0010] In the method for producing a metallic copper fine particle powder of the present invention, 1. The copper compound is any one of copper acetate, copper chloride, and copper bromide; 2. The polyol is any one of diethylene glycol, ethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and glycerin; is preferred. Effect of the Invention

[0011] In the metallic copper microparticle powder of the present invention, the powder state is maintained with an average secondary particle diameter in the range of 100 nm to 500 μm, so that the surface area is large, and since the amount of coating composed of fatty acids and / or ester compounds on the secondary particles of the metallic copper microparticles constituting the powder is reduced, the powder state can exhibit excellent antiviral properties. Furthermore, the metallic copper fine particle powder of the present invention has not only antiviral properties, but also properties such as antibacterial properties, electrical conductivity, ultraviolet shielding properties, antifouling properties, etc. In particular, it can exhibit antiviral properties regardless of the presence or absence of an envelope structure, and can also exhibit antiviral properties against viruses that do not have an envelope structure, such as norovirus. The metallic copper fine particle powder of the present invention can exist stably in the state of metallic copper even in the air atmosphere. In the method for producing metallic copper microparticle powder of the present invention, it is possible to efficiently remove components such as excess free fatty acids and ester compounds produced during the formation of metallic copper microparticles, or unreacted fatty acid copper, and to efficiently produce metallic copper microparticles in powder form. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a diagram showing the results of X-ray diffraction measurement of the metallic copper fine particle powders obtained in Example 1 and Comparative Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Metallic copper fine particle powder) The metallic copper microparticle powder of the present invention is a powder in a dry state consisting of metallic copper microparticles coated with a fatty acid and / or an ester compound, and metallic copper, which is an active ingredient exhibiting antiviral properties, can adsorb viruses and inactivate them, and can exhibit excellent antiviral properties regardless of the presence or absence of an envelope structure. In other words, the excellent antiviral properties of metallic copper microparticles are believed to be due to the oxidizing power of active oxygen generated from metallic copper, which denatures the proteins of viruses consisting of microproteins, and metallic copper reacts with the thiol groups of the viral proteins to denature the proteins, thereby inactivating the viruses. The mechanism by which metallic copper microparticles coated with fatty acids and / or ester compounds exhibit antiviral properties is not clear, but it is believed that viruses attached to the coating present on the surface of the metallic copper microparticles are replaced by the coating and come into contact with metallic copper.

[0014] In the metallic copper microparticle powder of the present invention, fatty acids and / or ester compounds are each coordinated around metallic copper microparticles, while the ester compounds have an affinity for fatty acids and are therefore considered to be coordinated around the fatty acids or in a mixed state with the fatty acids, which prevents oxidation of the microparticle surface caused by increased surface activity of the metallic copper microparticles, and can suppress aggregation of the microparticles, allowing excellent antiviral properties to be exhibited for a long period of time. Furthermore, as described below, in the metallic copper microparticles of the present invention, excess fatty acids, ester compounds, and unreacted fatty acid copper, etc. are efficiently removed during the production of the metallic copper microparticle powder, making filtration and washing easy and allowing the powder state to be maintained.In addition, the amount of fatty acid and ester compound coating on the metallic copper microparticles is 0.1 to 20 mass%, which is equivalent to that of metallic copper microparticles recovered by removing the solvent from a conventional dispersion liquid, so that the metallic copper microparticles can efficiently exhibit their properties such as antiviral properties. In the metallic copper fine particle powder of the present invention, the ester compound is sufficiently coated, so that particularly excellent virus resistance is exhibited.

[0015] Examples of fatty acids that may be used to coat the surface of the metallic copper microparticles include myristic acid, stearic acid, oleic acid, palmitic acid, n-decanoic acid, para-toic acid, succinic acid, malonic acid, tartaric acid, malic acid, glutaric acid, adipic acid, acetic acid, etc., and although combinations of multiple types of these may be used, higher fatty acids having 10 to 22 carbon atoms, and of these, stearic acid, are particularly preferred. The ester compound coating the surface of the metallic copper microparticles is preferably an ester compound derived from the fatty acids and polyols that are the raw materials in the method for producing metallic copper microparticle powder of the present invention described below, but it is also possible to blend ester compounds other than those derived from the raw materials, and these may be different ester compounds, but it is preferable that they are of the same type as the ester compounds derived from the raw materials. Suitable ester compounds for coating the surface of metallic copper microparticles include ester compounds of the above-mentioned fatty acids and the polyols described below, such as, but not limited to, diethylene glycol distearate, ethylene glycol distearate, propylene glycol distearate, polyethylene glycol distearate, and polypropylene glycol distearate.

[0016] In the present invention, the average primary particle size of the metallic copper particles is preferably in the range of 10 to 500 nm, particularly 10 to 200 nm. When the average primary particle size of the metallic copper particles is in the above range, it is possible to efficiently exhibit excellent antiviral performance. That is, metallic copper particles having such a small average primary particle size have a high contact rate with oxygen, so that they can efficiently generate active oxygen and can exhibit excellent antiviral performance. In addition, the average primary particle size referred to in this specification is the average of metallic copper particles with no gap between them, and the measurement method will be described later. The metallic copper microparticle powder of the present invention is composed of primary particles having the above-mentioned average primary particle size, and it is preferable that the average secondary particle size is in the range of 100 nm to 500 μm, particularly 100 nm to 100 μm, which allows the powder to exhibit excellent antiviral properties and also provides remarkably excellent handling properties, such as coatability.

[0017] (First Manufacturing Method) The metallic copper fine particle powder of the present invention can be prepared by the following production method. (1) First step A polyol dispersion liquid is prepared by adding fatty acid copper to a polyol and heating the mixture, in which metallic copper fine particles coated with a fatty acid and / or an ester compound of the fatty acid and a polyol are dispersed. In this case, it is more preferable that the metallic copper fine particles are coated with an ester compound of a fatty acid and a polyol. The heating temperature is lower than the decomposition starting temperature of the fatty acid copper used, and specifically, is preferably in the range of 160 to 230° C. The heating and mixing time is preferably 60 to 360 minutes.

[0018] The amount of fatty acid copper is preferably 0.1 to 5% by mass per polyol. When the amount of fatty acid copper is less than the above range, the efficiency of metal copper fine particle powder recovery is lower than when it is in the above range, and the economic efficiency is poor. When the amount of fatty acid copper is more than the above range, the efficiency of metal copper fine particle production is reduced, and the amount of impurities produced is increased, making it difficult to recover metal copper fine particle powder. There is no particular limit to the range of the amount of the fatty acid copper as long as production is possible, but when the amount of fatty acid copper is small, there is a risk that sufficient antiviral properties cannot be imparted to the dispersion liquid compared to when it is in the above range. On the other hand, when the amount of fatty acid copper is large, there is a risk that the economic efficiency is poor and the coatability and moldability are impaired compared to when it is in the above range. Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and glycerin, and are appropriately selected in combination with the low-boiling point solvent described below.

[0019] (2)Second process Next, the polyol dispersion in which the metallic copper particles coated with a fatty acid and / or an ester compound of the fatty acid and a polyol are dispersed is mixed with a low boiling point solvent to prepare a mixed liquid. The low boiling point solvent is preferably added in an amount of 10 to 200% by mass based on the polyol. Examples of low-boiling point solvents include esters such as methyl acetate, ethyl acetate, and butyl acetate, hydrocarbons such as hexane, heptane, toluene, xylene, and cyclohexane, and ketones such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone, but ester solvents are preferred, and among them, butyl acetate, ethyl acetate, and methyl isobutyl ketone can be preferably used. It is important that the low-boiling point solvent is not miscible with the polyol, and it is preferable to combine the polyol and the low-boiling point solvent so that the difference in solubility parameter (Sp value) between them is 3 or more. Preferably, when diethylene glycol (Sp value: 12.6) is used as the polyol, butyl acetate (Sp value: 8.4) is used as the low boiling point solvent.

[0020] In the method for producing metallic copper fine particle powder of the present invention, it is important that no dispersant is mixed into the low boiling point solvent. This allows metallic copper fine particles coated with fatty acid and / or ester compound to precipitate and remain in the polyol without migrating to the low boiling point solvent. On the other hand, impurities, in addition to excess fatty acid copper or free fatty acid or ester compound present in the polyol, migrate to the low boiling point solvent. As a result, metallic copper fine particles coated with fatty acid and / or ester compound are present in the polyol with reduced impurities.

[0021] In the method for producing metallic copper microparticles of the present invention, it is important in order to efficiently exhibit properties such as antiviral properties that the amount of fatty acid copper and / or ester compound coating the metallic copper microparticles is the minimum amount necessary to prevent oxidation and aggregation of the metallic copper. Since it is considered that the amount of ester compound of fatty acid and polyol produced in the first step described above that coats the metallic copper microparticles is sufficient, there is no need to intentionally add an ester compound to the low-boiling point solvent, but it may be possible to add it depending on the amount coated in the first step.

[0022] (3) Third step The mixed liquid is allowed to stand for 30 to 120 minutes at a temperature of 0 to 40° C. to cause phase separation of the polyol and the low-boiling solvent. When the mixed liquid is phase-separated, excess fatty acid copper, free fatty acid or fatty acid ester compound, or impurities present in the mixed liquid are extracted into the low-boiling solvent side, and metallic copper fine particles coated with fatty acid and / or ester compound of the fatty acid and polyol remain in a precipitated state in the polyol. Next, the low-boiling point solvent is removed from the phase-separated mixture to obtain a dispersion in which metallic copper particles coated with a fatty acid and / or an ester compound of the fatty acid and a polyol have precipitated in the polyol. The low boiling point solvent can be removed by a conventionally known separation method such as simple distillation, reduced pressure distillation, precision distillation, thin film distillation, extraction, or the like. The copper metal fine particle powder can be recovered from the polyol by a conventionally known separation method such as membrane separation, centrifugation, evaporation, pouring, etc., but is not limited thereto, and is preferably recovered by membrane separation. The separated metallic copper particles are washed with water, and then heated and dried at 40 to 50° C. for 60 to 360 minutes to thoroughly remove moisture, thereby obtaining a metallic copper particle powder in a dry state.

[0023] (Second Manufacturing Method) In addition to the above-mentioned method, the fine metallic copper particles coated with a fatty acid and an ester compound of a fatty acid in a low boiling point solvent can also be prepared by the following method. That is, by carrying out the same process as in the first manufacturing method described above, except that in the first step, a combination of a fatty acid and a copper compound is added instead of fatty acid copper, a dispersion liquid containing dispersed metallic copper microparticles coated with a fatty acid and / or an ester compound of the fatty acid can be prepared, and then by carrying out the second and third steps described above, a dry metallic copper microparticle powder can be obtained in the same manner.

[0024] (Third Manufacturing Method) The metallic copper fine particle powder of the present invention can be efficiently produced by the above-mentioned first and second production methods, in which metallic copper fine particles are coated with a fatty acid and / or an ester compound of the fatty acid and a polyol in an amount of 0.1 to 20 mass %, but metallic copper fine particle powder coated with a fatty acid and / or an ester compound can also be produced by the following method. That is, in addition to the above-mentioned liquid phase method, metallic copper fine particle powder coated with a fatty acid and an ester compound can also be produced by a gas phase method in which fatty acid copper is heated and reduced in an inert atmosphere such as air or a nitrogen atmosphere, and then the above-mentioned ester compound is added and the mixture is pulverized and mixed.

[0025] (Applications of metallic copper fine particle powder) As described above, the metallic copper microparticles of the present invention have excellent antiviral properties, and by fixing them to the surface of a molded body or containing them in a molded body, the metallic copper compound microparticle powder reacts with oxygen to generate active oxygen, making it possible to exhibit excellent antiviral performance. For example, the metallic copper microparticles can be dispersed in water such as purified water or ion-exchanged water; lower alcohols such as methanol, ethanol, propanol, isopropanol, butanol, or general denatured alcohols such as methanol-modified, benzol-modified, triol-modified, methyl ethyl ketone-modified, denatonium benzoate-modified, or fragrance-modified to form a dispersion liquid, or the metallic copper microparticles can be redispersed in the low-boiling point solvents mentioned above to form a dispersion liquid of metallic copper microparticles with an adjusted coating amount of fatty acid and / or ester compound of the fatty acid and polyol. When preparing the dispersion, it is preferable to add a dispersant to improve the dispersibility of the metallic copper fine particle powder in the dispersion medium. The amount of the dispersant to be added varies depending on the amount of metallic copper fine particles coated with fatty acid and / or ester compound of the fatty acid in the dispersion, but is preferably 0.01 to 2 mass % per dispersion medium. As the dispersant, a polymer dispersant having at least one of the following as an adsorption group: a primary, secondary or tertiary amine or an amine salt with a neutralized counter ion thereof, a carboxylic acid or a carboxylate, or a hydroxyl group, and having a fatty acid, polyether, polyester, polyurethane, or polyarylate in the main chain and side chain can be used. These dispersants have adsorption groups that adsorb to the surface of the copper compound microparticles, improve compatibility with non-aqueous solvents through the main chain or side chains, and generate repulsive forces due to steric hindrance of the polymer chains, suppressing aggregation of the copper compound microparticles, allowing them to be uniformly dispersed in the non-aqueous solvent, and eliminating aggregation over time. As the polymer dispersant, a type consisting of only a main chain, a type having a comb structure with side chains, or a type having a star structure can be used.

[0026] A dispersion liquid containing such metallic copper microparticle powder is suitable for use as a dilution solvent for a coating composition or a resin composition, thereby making it possible to impart antiviral properties to a coating film made of such a coating composition or a resin molded body made of the resin composition without impairing the transparency of the coating composition or resin composition. Examples of such coating compositions include those having a thermosetting resin such as a phenolic resin, an epoxy resin, a urethane resin, a melamine resin, a urea resin, an alkyd resin, an unsaturated polyester resin, or a silicone resin, or a photocurable acrylic resin as a base resin. In addition to the above-mentioned thermosetting resins, examples of the resin composition include olefin resins such as low-, medium-, and high-density polyethylene, linear low-density polyethylene, linear very low-density polyethylene, isotactic polypropylene, syndiotactic polypropylene, propylene-ethylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, and ethylene-propylene-butene-1 copolymer; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamide resins such as nylon 6, nylon 6,6, and nylon 6,10; and thermoplastic resins such as polycarbonate resins.

[0027] More specific examples of uses include molded articles obtained by using a nonwoven fabric, a resin film, a textile product, or the like as a substrate and applying a paint composition containing the antiviral composition to the surface of the substrate to form a coating film; and molded articles obtained by directly molding a resin composition containing the antiviral composition into a molded article such as a film, a sheet, a nonwoven fabric, or a fiber. EXAMPLES

[0028] (Preparation of metallic copper fine particle powder) [Example 1] 2.5% by mass of copper stearate was added to diethylene glycol and heated with stirring. After reaching 190°C, the mixture was heated for 2 hours and then cooled to 120°C or less, butyl acetate was added, and the mixture was stirred for about 1 minute. After the mixture was left to stand and the diethylene glycol layer and butyl acetate layer were separated, the butyl acetate layer was removed to obtain a diethylene glycol dispersion containing metallic copper particles. This diethylene glycol dispersion was suction filtered through a membrane filter with a pore size of 10 μm, washed with water, and then dried at 50° C. for 2 hours to obtain a metallic copper fine particle powder. The results of X-ray diffraction measurement of the obtained metallic copper fine particle powder are shown in FIG.

[0029] [Example 2] A metallic copper fine particle powder was prepared in the same manner as in Example 1, except that the heating temperature was changed to 210°C.

[0030] [Example 3] A metallic copper fine particle powder was prepared in the same manner as in Example 1, except that copper stearate was changed to copper laurate.

[0031] [Example 4] A metallic copper fine particle powder was prepared in the same manner as in Example 1, except that copper stearate was changed to stearic acid and copper acetate.

[0032] [Example 5] A metallic copper fine particle powder was prepared in the same manner as in Example 1, except that diethylene glycol was changed to ethylene glycol.

[0033] [Example 6] A metallic copper fine particle powder was prepared in the same manner as in Example 1, except that diethylene glycol was changed to glycerin.

[0034] (Preparation of metallic copper particle dispersion) [Reference example 1] 0.5% by mass of a dispersant, DISPERBYK-2060 (manufactured by BYK-Chemie), was added to distilled water and stirred. Next, the copper metal fine particle powder obtained in Example 1 was added so that the copper metal content was 0.5% by mass, and stirred. Ultrasonic treatment was performed for 10 minutes to obtain a copper metal fine particle-containing dispersion.

[0035] [Reference example 2] 0.5% by mass of a dispersant, DISPERBYK-2090 (manufactured by BYK-Chemie), was added to butyl acetate and stirred. Next, the copper metal fine particle powder obtained in Example 1 was added so that the copper metal content was 0.5% by mass and stirred. Ultrasonic treatment was performed for 10 minutes to obtain a copper metal fine particle-containing dispersion.

[0036] [Comparative Example 1] The preparation was carried out in the same manner as in Example 1, except that copper stearate was changed to copper sulfate.

[0037] [Comparative Example 2] The preparation was carried out in the same manner as in Example 1, except that the heating temperature was changed to 150°C.

[0038] [Comparative Example 3] The same preparation as in Example 1 was carried out except that the drying temperature was changed to 120° C. The results of X-ray diffraction measurement of the obtained metallic copper fine particle powder are shown in FIG.

[0039] [Comparative Example 4] 0.05% by mass of metallic copper microparticle reagent (Sigma-Aldrich) and 1.0% by weight of DISPERBYK-2090 were added to butyl acetate, and the mixture was stirred with an ultrasonic vibration device to obtain a dispersion.

[0040] [Comparative Example 5] The preparation was carried out in the same manner as in Example 1, except that the step of adding butyl acetate, leaving it to stand, and then removing the butyl acetate layer was not carried out.

[0041] [Example 7] 2.5% by mass of copper stearate was added to diethylene glycol, and the mixture was heated with stirring. After reaching 190°C, the mixture was heated for 2 hours, and then cooled to 60°C. Next, butyl acetate containing 1.0% by mass of dispersant DISPERBYK-2090 (manufactured by BYK-Chemie) and 1.0% by mass of diethylene glycol distearate was added and stirred. After leaving to stand for about 1 hour, the butyl acetate layer was collected to prepare a metallic copper microparticle dispersion. This metallic copper microparticle dispersion was suction filtered through a membrane filter with a pore size of 0.1 μm, washed with water, and dried at 50°C for 2 hours to obtain metallic copper microparticle powder.

[0042] (Identification of the metal composition of fine particles) The metal composition of the produced metallic copper fine particle powder was measured using a powder X-ray diffractometer manufactured by Rigaku Corp. The measurement range was 2θ=30° to 60°, and in the case of metallic copper, peaks appeared at positions of 43° and 50°.

[0043] (Antiviral evaluation) (Method of applying dispersion to nonwoven fabric) [In the case of aqueous dispersion] A coating liquid was prepared by mixing 90% by mass of a dispersion liquid adjusted so that the concentration of metallic copper in the binder resin was 0.05% by mass with 9.95% by mass of acrylic resin as the binder resin. An unprocessed nonwoven fabric was immersed in the coating liquid, taken out, and the excess liquid was removed with a roller-type wringer, and then dried in a dryer at 80°C for 5 minutes. Then, it was dried in a dryer at 150°C for 2 minutes to obtain a nonwoven fabric with metallic copper fine particle powder fixed therein.

[0044] [Solvent-based dispersion] A coating liquid was prepared by mixing 90% by mass of a dispersion liquid adjusted so that the metallic copper component concentration in the binder resin was 0.05% by mass, 9.9% by mass of a photocurable acrylic resin as a binder resin, and 0.1% by mass of a photopolymerization initiator. An unprocessed nonwoven fabric was immersed in the coating liquid, taken out, and the excess liquid was removed with a roller-type wringer, and then dried in a dryer at 90°C for 2 minutes. Then, UV irradiation was performed for 10 minutes to obtain a nonwoven fabric with metallic copper fine particle powder fixed therein.

[0045] (Method for evaluating antiviral properties of nonwoven fabric) 1. Host cells are infected with the virus, cultured, and then the cell debris is removed by centrifugation to obtain a virus suspension. 2. Dilute the virus suspension from step 1 above 10-fold with sterile distilled water to prepare the test virus suspension. 3. Inoculate 0.2 mL of the test virus suspension onto a 0.4 g test piece of nonwoven fabric. 4. After leaving the specimen at 25°C for 2 hours, add 20 mL of SCDLP medium and mix with a vortex mixer to wash out the virus from the specimen. 5. Measure the viral infectivity using the plaque assay method and calculate the antiviral activity value. 6. If the antiviral activity value is 3.0 or higher, it can be determined that the product has sufficient antiviral properties against that virus.

[0046] (Method for measuring the total amount of fatty acids and / or ester compounds) Using a simultaneous differential thermogravimetry analyzer (TG / DTA7220, Hitachi High-Tech Science Corp.), approximately 10 mg of powder sample was heated in a nitrogen atmosphere to 600° C. at a rate of 10° C. / min. The weight loss from the resulting chart was determined to be the total amount of fatty acids and ester compounds.

[0047] (Method for measuring the average primary particle size and average secondary particle size of metallic copper particles) Measurement method of average primary particle size: A powder sample was observed with a scanning electron microscope (S-4800, Hitachi High-Tech Science Co., Ltd.) and images were obtained. The average primary particle size was calculated using image analysis type particle size distribution measurement software Mac-View. Measurement method for average secondary particle size of powdered metallic copper fine particles: The average secondary particle size was measured by a wet method using a laser diffraction particle size distribution measuring device (SALD-3100, manufactured by Shimadzu Corporation).

[0048] Table 1 shows whether metallic copper microparticles (dispersion) could be prepared, and the amount of fatty acid and / or ester compound coated on the metallic copper microparticles obtained in Examples 1 and 7 and Comparative Example 5, while Table 2 shows the results of the antiviral evaluation against influenza virus and feline calicivirus of nonwoven fabrics using the metallic copper microparticle dispersions obtained in Examples 1, 6 and Comparative Examples 4 and 5.

[0049] [Table 1]

[0050] [Table 2] [Industrial Applicability]

[0051] The metallic copper microparticle powder of the present invention can be in the form of a dispersion liquid and contained as a diluent in a resin composition constituting a textile product, etc., or directly applied to or impregnated into a textile product, etc., thereby imparting antiviral properties to textile products such as paper products, masks, wet tissues, air conditioner filters, air purifier filters, clothing, work clothes, curtains, carpets, automotive parts, packaging parts, freshness-preserving materials, sheets, towels, bath mats, diaper covers, stuffed animals, slippers, shoe insoles, and cleaning supplies such as wipers. Furthermore, by using a low-boiling point solvent as the dispersion medium of the dispersion, it can also be used as a diluent for a paint composition or a resin composition, thereby making it possible to impart antiviral properties to the coating film or resin molded product. Furthermore, the material can be used for medical equipment, packaging films for medical equipment, waste containers, garbage bags, wall materials and floor materials in nursing homes or public facilities such as hospitals and schools, wax coating materials, and vomit disposal equipment. Furthermore, in addition to sanitary products, the composition can be used for a variety of applications, including conductive films, films, metal plates, glass plates, marine paints, heat exchanger fins, ceramic products such as tableware, rubber products, metal products such as faucets, additives for humidifiers, liquid detergents, and ion adsorbents.

Claims

1. A method for producing metallic copper microparticle powder, comprising the steps of: adding fatty acid copper to a polyol and heating and mixing the polyol to prepare a dispersion in which metallic copper microparticles coated with fatty acids and / or ester compounds of the fatty acids and polyol are dispersed; mixing the dispersion with a low-boiling point solvent, separating the polyol and the low-boiling point solvent into two phases, and transferring the free fatty acids and ester compounds in the polyol to the low-boiling point solvent; removing the low-boiling point solvent after the two-phase separation; and recovering the metallic copper microparticles coated with fatty acids and / or ester compounds in the polyol from which the low-boiling point solvent has been removed.

2. A method for producing metallic copper microparticle powder, comprising the steps of: adding a fatty acid and a copper compound to a polyol, heating and mixing the resulting mixture to prepare a dispersion in which metallic copper microparticles coated with fatty acids and / or ester compounds of the fatty acids and polyol are dispersed; mixing the dispersion with a low-boiling point solvent, separating the polyol and the low-boiling point solvent into two phases, and transferring the free fatty acids and ester compounds in the polyol to the low-boiling point solvent; removing the low-boiling point solvent after the two-phase separation; and recovering the metallic copper microparticles coated with fatty acids and / or ester compounds in the polyol from which the low-boiling point solvent has been removed.

3. 3. The method for producing metallic copper fine particles according to claim 2, wherein the copper compound is any one of copper acetate, copper chloride, and copper bromide.

4. 4. The method for producing metallic copper fine particles according to claim 1, wherein the polyol is any one of diethylene glycol, ethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and glycerin.

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