Article having zinc oxide coating film, method for producing same,

Abstract

Provided is an article having a zinc oxide coating film on a substrate, the surface area increase rate (Sdr) measured on the surface of the zinc oxide coating film being 2.00-13.00%, and the antibacterial activity value (in accordance with JIS Z 2801: 2010) being 2.0 or more.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Japanese Patent Application No. 2022-076434 filed on May 6, 2022 and Japanese Patent Application No. 2022-150089 filed on September 21, 2022, the entire contents of which are expressly incorporated herein as if disclosed. Technical Field

[0003] The present invention relates to an article having a zinc oxide coating, a method for producing the article, and a method for deodorizing the article. Background Art

[0004] Zinc oxide is also called zinc flower or zinc white, and is used for industrial purposes as a white pigment, for example. In addition, fine-particle zinc oxide has an ultraviolet shielding effect and visible light transparency, and for this reason, zinc oxide is widely used in various applications such as cosmetics, sunscreens, pharmaceuticals, coatings, and plastics (for example, see Patent Documents 1 to 8 (all of which are specifically cited as disclosed herein).

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-95655

[0006] Patent Document 2: Japanese Patent Publication No. 1-50202

[0007] Patent Document 3: Japanese Patent Application Publication No. 2018-115098

[0008] Patent Document 4: Japanese Patent Application Publication No. 2021-001278

[0009] Patent Document 5: Japanese Patent Application Laid-Open No. 5-156510

[0010] Patent Document 6: International Publication No. WO2013 / 073555 Pamphlet

[0011] Patent Document 7: Japanese Patent Application Laid-Open No. 9-286615

[0012] Patent Document 8: Japanese Patent Application Publication No. 2011-170979 Summary of the invention

[0013] Patent Documents 1 to 3 propose using zinc oxide, which has been given strong water repellency by surface treatment with silicone, for cosmetic applications.

[0014] On the other hand, zinc oxide has attracted attention in recent years for its antimicrobial activity. In this regard, Patent Documents 4 to 7 propose providing an article with antimicrobial properties by using zinc oxide.

[0015] In addition, as a method for forming a zinc oxide film on the surface of an article, Patent Document 8 discloses a method for forming a zinc oxide film from a composition based on a partial hydrolyzate of an organic zinc compound.

[0016] In view of the above, one embodiment of the present invention provides an antimicrobial article having a zinc oxide coating.

[0017] One embodiment of the present invention is as follows.

[0018] [1] An article having a zinc oxide coating on a substrate, wherein:

[0019] The surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 13.00% or less, and the antimicrobial activity value (based on JIS Z 2801:2010) is 2.0 or more.

[0020] [2] The article according to [1], wherein the antiviral activity value (based on ISO 21702) measured on the surface of the zinc oxide coating is 2.0 or more.

[0021] [3] The article according to [1] or [2], wherein the zinc oxide coating has a thickness of 50 nm to 1000 nm.

[0022] [4] The article according to any one of [1] to [3], wherein the transmittance of the zinc oxide coating at a wavelength of 550 nm is 80.0% or more.

[0023] [5] The article according to any one of [1] to [4], wherein a surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 9.00% or less.

[0024] [6] The article according to [1] or [2], wherein the zinc oxide coating has a thickness of 50 nm to 1000 nm, and a transmittance of 80.0% or more at a wavelength of 550 nm.

[0025] [7] The article according to [6], wherein a surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 9.00% or less.

[0026] [8] The article according to [1], wherein the antiviral activity value (according to ISO 21702) measured on the surface of the zinc oxide coating is 2.0 or more,

[0027] The zinc oxide film has a thickness of 50 nm to 1000 nm.

[0028] The zinc oxide coating has a transmittance of 80.0% or more at a wavelength of 550 nm.

[0029] [9] The article according to [8], wherein a surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 9.00% or less.

[0030]

[10] The article according to any one of [1] to [9], which is a deodorizing material.

[0031]

[11] The method for producing an article according to any one of [1] to

[10] , comprising:

[0032] In the presence of water, a coating liquid containing an organic zinc compound represented by the following formula (1) is applied to form the zinc oxide coating.

[0033] Formula (1): R 1 -Zn-R 2

[0034] In formula (1), R 1 and R 2 Each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms.

[0035]

[12] The production method according to

[11] , wherein the coating is performed under atmospheric pressure.

[0036]

[13] The production method according to

[11] or

[12] , wherein the organozinc compound represented by the formula (1) is diethylzinc.

[0037]

[14] A deodorization method, comprising: placing the article described in

[10] in an atmosphere containing a deodorization target gas.

[0038]

[15] The deodorization method according to

[14] , wherein the deodorization target gas is selected from hydrogen sulfide gas, methyl mercaptan gas and isovaleric acid gas.

[0039] According to one embodiment of the present invention, an article having antibacterial properties by having a zinc oxide coating can be provided. In addition, according to one embodiment of the present invention, a method for manufacturing the article can be provided. Furthermore, according to one embodiment of the present invention, a deodorization method using the article can be provided. DETAILED DESCRIPTION

[0040] [Articles with zinc oxide coating]

[0041] One embodiment of the present invention relates to an article having a zinc oxide coating on a substrate, wherein a surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% to 13.00% and an antimicrobial activity value (based on JISZ 2801:2010) is 2.0 or more.

[0042] In the repeated research on antibacterial articles with zinc oxide coatings, the inventors of the present invention have clarified that there is a correlation between the surface structure of the zinc oxide coating and the antibacterial activity. This is a new insight obtained through the research of the inventors of the present invention, which is not recorded in the literature shown above. Moreover, the inventors of the present invention have further repeatedly conducted in-depth research, and as a result, newly discovered that the zinc oxide coating with a surface area increase rate Sdr of 2.00% or more measured on the surface can show an antibacterial activity value of 2.0 or more. Furthermore, the inventors of the present invention have also newly discovered that the zinc oxide coating with a surface area increase rate Sdr of 2.00% or more measured on the surface can show an antiviral activity value of 2.0 or more. That is, according to one embodiment of the present invention, an article having a zinc oxide coating on a substrate can also be provided, wherein the surface area increase rate Sdr measured on the surface of the above-mentioned zinc oxide coating is 2.00% or more and 13.00% or less, and the antiviral activity value (according to ISO 21702) is 2.0 or more.

[0043] The above items are described below in more detail.

[0044] <Zinc oxide coating>

[0045] (Surface area increase rate Sdr)

[0046] "Surface area increase rate Sdr" is a surface property parameter specified in ISO25178-2:2012, also commonly referred to as "interface development area ratio", which indicates how much the development area (surface area) of the defined area has increased relative to the area of ​​the defined area. Specifically, it indicates how much the surface area (developed area) of the surface of the zinc oxide coating has increased relative to the surface area of ​​the defined area when the surface of the substrate on which the zinc oxide coating is provided is used as the defined area. The Sdr of a completely flat surface is 0%. The measurement is performed using a laser microscope. A laser microscope is a non-contact microscope that uses a laser as a light source and can measure the concavities and convexities of the surface of a target object in three dimensions. As measurement conditions, for example, the measurement conditions described in the embodiment column described later can be adopted. Hereinafter, the "surface area increase rate Sdr" will also be referred to as "Sdr".

[0047] From the viewpoint of improving antibacterial activity, the surface area increase rate Sdr measured on the surface of the zinc oxide coating on the substrate of the above-mentioned article is 2.00% or more, preferably 2.20% or more, and more preferably 2.40% or more, 2.60% or more, 2.80% or more, 3.00% or more, 3.20% or more, 3.40% or more, 3.60% or more, 3.80% or more, 4.00% or more, 4.20% or more, 4.40% or more, and 4.60% or more. In addition, from the viewpoint of improving antiviral activity, the surface area increase rate Sdr measured on the surface of the zinc oxide coating on the substrate of the above-mentioned article is preferably in the above range.

[0048] There are many different opinions about the antibacterial mechanism of zinc oxide, but it is believed that there is a mechanism in which zinc ions destroy cell membranes, and a mechanism in which hydrogen peroxide produced on the surface of zinc oxide damages bacterial DNA or enzymes, causing their death.

[0049] The inventors of the present invention believe that the antibacterial effect brought about by the production of hydrogen peroxide, in particular, the antibacterial effect of the hydroxyl radicals produced by hydrogen peroxide is great (see Journal of the Caeramic Society of Japan 106

[10] 1007-1011(1998)). In addition, as an antiviral mechanism of zinc oxide, the inventors of the present invention consider a mechanism in which the active oxygen (such as hydroxyl radicals produced by hydrogen peroxide, etc.) damages the membrane of the virus particle called the envelope, thereby killing the virus.

[0050] Hydrogen peroxide is produced by contact of zinc oxide with oxygen and / or water on the surface. Therefore, the inventors of the present invention believe that by adjusting the surface structure of the zinc oxide coating, in particular increasing the value of Sdr, the amount of hydrogen peroxide produced is increased, and as a result, the antibacterial activity can be improved, and the antiviral effect can also be improved. In the past, in order to improve the antibacterial activity of zinc oxide, only studies on controlling the particle size of zinc oxide particles or increasing the specific surface area of ​​zinc oxide particles were conducted (refer to Japanese Patent Publication No. 2021-001278 (Patent Document 4), Japanese Patent Publication No. 5-156510 (Patent Document 5), International Publication No. WO2013 / 073555 Pamphlet (Patent Document 6), Japanese Patent Publication No. 9-286615 (Patent Document 7)), and no proposals were made on the surface structure of the zinc oxide coating on the substrate of the article.

[0051] On the other hand, from the viewpoint of having transparency that allows the transparent film to function on the substrate of the article, the surface area increase rate Sdr is 13.00% or less, preferably 12.00% or less, more preferably 11.00% or less, and further preferably 10.00% or less, 9.00% or less, 8.80% or less, 8.60% or less, 8.40% or less, 8.20% or less, and 8.00% or less. The means for controlling the Sdr will be described later.

[0052] (Antibacterial activity value)

[0053] The antimicrobial activity value (according to JIS Z2801:2010) measured on the surface of the zinc oxide coating on the substrate of the above article is 2.0 or more. The article showing such an antimicrobial activity value is useful as an antimicrobial article in various applications.

[0054] The "antimicrobial activity value" in the present invention and this specification refers to the antimicrobial activity value for at least one or both of Escherichia coli and Staphylococcus aureus as the test bacteria recorded in JIS Z2801:2010. The antimicrobial activity value is an index value according to the test method in JIS Z 2801:2010 "Antibacterial processed products-Antibacterial test method·Antibacterial effect". In addition, in one embodiment, the antimicrobial activity value measured on the surface of the zinc oxide coating on the substrate of the above-mentioned article with methicillin-resistant Staphylococcus aureus as the test bacteria according to the test method in JIS Z2801:2010 "Antibacterial processed products-Antibacterial test method·Antibacterial effect" may also be 2.0 or more. In one embodiment, the antimicrobial activity value measured on the surface of the zinc oxide coating on the substrate of the above-mentioned article with Klebsiella pneumoniae as the test bacteria according to the test method in JIS Z2801:2010 "Antibacterial processed products-Antibacterial test method·Antibacterial effect" may also be 2.0 or more. In one embodiment, the antibacterial activity value measured by the test method in JIS Z2801:2010 "Antibacterial processed products - Antibacterial test method · Antibacterial effect" on the surface of the zinc oxide coating on the substrate of the above-mentioned article may be 2.0 or more. In one embodiment, the antibacterial activity value measured by the test method in JIS Z2801:2010 "Antibacterial processed products - Antibacterial test method · Antibacterial effect" on the surface of the zinc oxide coating on the substrate of the above-mentioned article may be 2.0 or more.

[0055] The above antimicrobial activity value is a value obtained by inoculating the test bacteria on the antimicrobial processed product and the unprocessed product and culturing them for 24 hours as the difference in the average value of the logarithmic value of the number of viable bacteria of the two. If the antimicrobial activity value thus obtained is 2.0 or more, it can be said that the bacteria killing rate is 99% or more, and it is generally considered to have antimicrobial activity. The above article has a coating containing zinc oxide having antimicrobial activity on the substrate, and the Sdr on its surface is within the range described above, thereby showing a high antimicrobial activity value of 2.0 or more.

[0056] (Antiviral activity value)

[0057] The antiviral activity value (according to ISO 21702) measured on the surface of the zinc oxide coating on the substrate of the above-mentioned article may be 2.0 or more. The article showing such an antiviral activity value is useful as an antiviral article in various applications.

[0058] The "antiviral activity value" in the present invention and this specification refers to at least the antiviral activity value for the new coronavirus SARS-COV-2 (COVID-19). The antiviral activity value is an index value based on the test method in ISO 21702 "Measurement of antiviral activity on plastics and other non-porous surfaces". The new coronavirus SARS-COV-2 (COVID-19) is an enveloped virus. In one embodiment, on the surface of the zinc oxide coating on the substrate of the above-mentioned article, influenza virus, measles virus, rubella virus, HIV, herpes virus and other enveloped viruses are used as the tested viruses, and the antiviral activity value measured according to the test method in ISO 21702 "Measurement of antiviral activity on plastics and other non-porous surfaces" can also be 2.0 or more. The above-mentioned article can show high antiviral effects on various viruses with envelopes.

[0059] The above antiviral activity value is a value obtained by inoculating the test virus into the antiviral processed product and the unprocessed product and culturing them for 24 hours, and then calculating the difference between the average values ​​of the logarithmic values ​​of the number of live viruses in the two. If the antiviral activity value thus calculated is 2.0 or more, it can be said that the virus killing rate is 99% or more, and it is generally considered to have antiviral activity. The above article has a coating containing zinc oxide having antiviral activity on a substrate, and the Sdr on its surface is within the range described above, thereby being able to show a high antiviral activity value of 2.0 or more.

[0060] (film thickness)

[0061] The film thickness of the zinc oxide coating can be appropriately adjusted according to the purpose, and is not particularly limited. For example, the film thickness of the zinc oxide coating can be more than 50nm, more than 100nm, more than 150nm, more than 200nm, more than 250nm, more than 300nm, more than 350nm, more than 400nm, more than 450nm, more than 500nm, more than 550nm or more than 600nm. The film thickness of the zinc oxide coating can be, for example, less than 10μm. From the viewpoint of the transparency of the zinc oxide coating, its film thickness is preferably less than 2000nm, more preferably less than 1500nm, and further preferably less than 1000nm. According to the research of the inventors, it is found that the value of Sdr of the zinc oxide coating tends to increase when the film thickness becomes thicker. Therefore, as an example of a means of controlling Sdr, adjusting the film thickness can be cited. The film thickness can be measured by a stylus-type surface shape measuring device. As an example of a measuring device, a measuring device described in the embodiment column described later can be cited.

[0062] (Transmittance)

[0063] From the viewpoint of the usefulness of the above-mentioned article in various applications, the above-mentioned zinc oxide coating preferably has high transparency. In this regard, the above-mentioned zinc oxide coating preferably has a high visible light transmittance. For example, the transmittance of the above-mentioned zinc oxide coating is preferably 80.0% or more at a wavelength of 550nm, more preferably 82.0% or more, further preferably 85.0% or more, more preferably 88.0% or more, and further preferably 90.0% or more. The above-mentioned transmittance can be, for example, less than 100%, less than 99.0%, less than 98.0%, less than 97.0%, less than 96.0% or less than 95.0%. The higher the transmittance, the higher the transparency, the more preferred. The above-mentioned transmittance can be measured by a commercially available spectrophotometer.

[0064] The article may have the above-mentioned zinc oxide coating on at least a portion of the substrate. In addition, the above-mentioned zinc oxide coating is preferably provided as the outermost layer of the article at the location where the coating is provided. For the above-mentioned article, when the substrate has a front and a back shape, for example, the above-mentioned zinc oxide coating may be provided on a portion or the entire surface of either or both of the front and back surfaces. In addition, the above-mentioned zinc oxide coating may also be provided on at least a portion or the entire surface of the side surface of the substrate. The substrate may be a single substrate, or may be obtained by providing one or more layers on a substrate.

[0065] <Substrate>

[0066] The substrate is not particularly limited as long as it is an article to which antibacterial and / or antiviral properties are to be imparted. In one embodiment, the substrate is preferably a substrate to which the coating liquid described below can be easily applied.

[0067] The material constituting the substrate is not particularly limited, and examples thereof include metals, metal oxides, glass, concrete, various plastics, paper, and wood. A composite material including one or more of these materials may also be used.

[0068] The shape of the substrate may be a plate shape, a curved shape, or a substrate having irregularities on the surface.

[0069] The article has the zinc oxide coating on the substrate, and can show high antibacterial performance with an antibacterial activity value of 2.0 or more, and is useful as an article called an antibacterial article, an antibacterial processed article, an antibacterial processed product, etc. Furthermore, the article has the zinc oxide coating on the substrate, and can show high antiviral performance with an antiviral activity value of 2.0 or more, and is useful as an article called an antiviral article, an antiviral processed article, an antiviral processed product, etc.

[0070] The above-mentioned articles are not particularly limited, and examples thereof include various articles requiring antibacterial and / or antiviral properties that are set up in medical institutions, commercial facilities, schools, public facilities, food / pharmaceutical factories, research institutions, nursing sites, cooking / food-related sites, transportation institutions, etc. Specific examples of such articles include doors, door handles, handrails, handles, faucets, glass, laboratory equipment, tables, chairs, home appliances, office supplies, medical equipment, buttons, keyboards, mice, touch panels, portable communication devices, vein / fingerprint authentication devices, operation buttons, switches, etc.

[0071] The zinc oxide coating of the article preferably exhibits high transparency, thereby providing visibility, and zinc oxide also has the property of shielding ultraviolet rays. Therefore, the zinc oxide coating can also help inhibit the degradation of antibacterial and / or antiviral articles due to ultraviolet rays.

[0072] In addition, the research results of the present inventors also show that the above-mentioned articles can show a deodorizing effect on malodorous gases. For example, by arranging the above-mentioned articles in an atmosphere containing a target gas for deodorization, the above-mentioned articles function as a deodorizing material and can reduce the concentration of malodorous gases in the above-mentioned atmosphere. That is, one embodiment of the present invention relates to a deodorizing method, which includes arranging the above-mentioned articles in an atmosphere containing a target gas for deodorization. Malodorous gases that are targets for deodorization include, for example, gases such as hydrogen sulfide, methyl mercaptan, and isovaleric acid. The atmosphere containing the target gas for deodorization may be a closed atmosphere or an open atmosphere. The volume, shape, and concentration of the target malodorous gas of the atmosphere containing the target gas for deodorization are not particularly limited.

[0073] [Method for producing the above article]

[0074] One aspect of the present invention relates to a method for producing the above-mentioned article, comprising: forming the above-mentioned zinc oxide coating by applying a coating liquid containing an organic zinc compound represented by the following formula (1) in an atmosphere in the presence of water.

[0075] Formula (1): R 1 -Zn-R 2

[0076] In formula (1), R 1 and R 2 Each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms.

[0077] In the present invention and this specification, "zinc oxide coating" refers to a coating containing zinc oxide. In the above-mentioned manufacturing method, the zinc oxide coating can be formed by hydrolysis of the organic zinc compound represented by formula (1). The method is a method in which a zinc oxide coating can be formed without an adhesive, relative to a method in which a zinc oxide coating is formed using a coating liquid containing zinc oxide particles and an adhesive. In addition, according to the method, zinc oxide can also be firmly attached to the surface of a substrate as a covered surface. Articles requiring antibacterial properties are sometimes sterilized, usually by steam sterilization (moist heat sterilization) or dry heat sterilization. Regardless of the type of sterilization treatment, heating above 130°C is usually performed, so it is expected that the zinc oxide coating subjected to such sterilization treatment has high heat resistance. Compared with the zinc oxide coating formed using zinc oxide particles and an adhesive, the zinc oxide coating formed by the above-mentioned method is preferred from the viewpoint of being able to exhibit high heat resistance. However, the article involved in one embodiment of the present invention described in detail above is not limited to the article manufactured by the manufacturing method described below.

[0078] <Composition of coating liquid>

[0079] (Organozinc compound represented by formula (1))

[0080] The above-mentioned organic zinc compound is represented by the following formula (1).

[0081] Formula (1): R 1 -Zn-R 2 (1)

[0082] Hereinafter, the formula (1) will be described in more detail.

[0083] In formula (1), R 1 and R 2 Each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms. The organozinc compound represented by formula (1) is a dialkylzinc. 1 and R 2 In one embodiment, it represents the same alkyl group, and in another embodiment, it represents different alkyl groups.

[0084] Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, isohexyl, sec-hexyl, tert-hexyl, 2-hexyl, heptyl, 2-ethylhexyl, and octyl.

[0085] The compound represented by formula (1) preferably has an alkyl group having 1 to 3 carbon atoms as the alkyl group, and diethylzinc (ie, R 1 and R 2 are ethyl).

[0086] The concentration of the organozinc compound represented by formula (1) in the coating solution is preferably 15% by mass or less, more preferably 14% by mass or less, further preferably 13% by mass or less, and 12% by mass or less, based on the total amount of the coating solution as 100% by mass. In addition, the above concentration is, for example, preferably 1% by mass or more, more preferably 2% by mass or more, and further preferably 3% by mass or more.

[0087] From the viewpoints of manufacturing a zinc oxide film having a sufficient film thickness to exhibit antibacterial and / or antiviral properties, manufacturing a transparent zinc oxide film, and suppressing nozzle clogging associated with storage time and solvent volatilization, the concentration of the organic zinc compound represented by formula (1) of the above-mentioned coating liquid is preferably within the above-mentioned range. In addition, according to the research of the present inventors, if the concentration of the organic zinc compound represented by formula (1) of the above-mentioned coating liquid is increased, it can be seen that the Sdr value of the formed zinc oxide film tends to increase. Therefore, as an example of a means of controlling Sdr, adjustment of the above-mentioned concentration can be cited.

[0088] (Solvent)

[0089] The coating solution at least comprises one or more compounds represented by formula (1), and can usually further comprise a solvent. The solvent is not particularly limited, and for example, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, petroleum ether, aromatic hydrocarbon solvents such as benzene, toluene, ethylbenzene, xylene, mesitylene, cyclohexylbenzene, 1,2-diethoxyethane, diethyl ether, diisopropyl ether, glycol dimethyl ether, diglyme, triglyme, dioxane, tetrahydrofuran, ether solvents such as anisole, etc., can be cited. In addition, the solvent can be used only one, or two or more can be mixed and used in any proportion. If the solubility of the organozinc compound, the volatility of the solvent, etc., are taken into consideration, then as the solvent, preferably xylene, mesitylene, etc.

[0090] The coating liquid may contain only the above-mentioned components, or may contain one or more known components in any ratio.

[0091] <Application of coating liquid>

[0092] The coating of the above-mentioned coating liquid is carried out in an atmosphere in which water is present. The relative humidity of the "atmosphere in which water is present" can be, for example, 20% or more and 100% or less. The "atmosphere in which water is present" can be, for example, an atmosphere of air containing water with a relative humidity of 20 to 100%. Alternatively, the "atmosphere in which water is present" can also be an atmosphere of a mixed gas in which nitrogen and water are mixed instead of the above-mentioned air atmosphere. From the viewpoint of smooth formation of the zinc oxide coating, the relative humidity of the "atmosphere in which water is present" is preferably 40% or more and 100% or less, and from the viewpoint of increasing the value of Sdr, it is preferably 50% or more and 100% or more and 90% or less. As an example of a means of controlling Sdr, the relative humidity of the atmosphere in which coating is performed can be cited. For example, through research by the inventors and others, it has been confirmed that the higher the relative humidity of the atmosphere in which coating is performed, the greater the Sdr value of the formed zinc oxide coating.

[0093] By applying the above-mentioned coating liquid on the surface of the substrate, the above-mentioned zinc oxide coating can be formed on the surface of the substrate. The details of the substrate are as described above. As the coating method of the above-mentioned coating liquid, known methods such as spraying, electrostatic coating, spin coating, and dip coating can be used. From the viewpoint of not selecting the shape of the substrate, spraying is preferred. Regarding the control of Sdr, through the research of the present inventors, it has been confirmed that when the spray pressure in the spraying is reduced, the Sdr value of the formed zinc oxide coating becomes larger. Therefore, as an example of a means of controlling Sdr, adjusting the spray pressure in the spraying can be cited. For example, the spray pressure can be a set value in the spraying device used. The spray pressure can be set according to the specifications of the spraying device, etc., and is not particularly limited. In addition, by repeatedly spraying more than 2 times, the thickening of the zinc oxide coating can be sought.

[0094] The spray coating will be described in detail below, but the present invention is not limited to the following description.

[0095] The substrate surface can be sprayed under atmospheric pressure or under pressure, preferably under atmospheric pressure, in an atmosphere in which water is present. It is simple to implement on the device under atmospheric pressure, so it is preferred. As a spraying device, a commercially available spraying device and a spraying device of a known structure can be used. As a spraying device, there are a spraying device with a movable nozzle and a spraying device with a fixed nozzle. In the spraying device with a movable nozzle, the nozzle moves in the X direction and the Y direction during spraying. According to the research of the inventors, if a spraying device with a movable nozzle is used, a tendency is observed that the value of Sdr of the formed zinc oxide coating becomes larger compared with the case of using a spraying device with a fixed nozzle.

[0096] The spraying on the substrate surface can be performed by heating the substrate. The substrate temperature during spraying can be set to, for example, below 350°C, and the substrate temperature can be controlled by a known heating device such as a heater. It should be noted that in the present invention and this specification, the so-called "substrate temperature" refers to the temperature of the substrate surface on which the coating liquid is applied. As needed, the substrate temperature can be set to a specified temperature, and after the solvent is dried, heating for zinc oxide formation is performed at a specified temperature. It is also possible to make the solvent drying temperature the same as the substrate temperature for subsequent zinc oxide formation, and perform solvent drying and zinc oxide formation at the same time. Regarding the substrate temperature, it can also be appropriately set according to the type of solvent contained in the coating liquid, such as by heating in multiple stages.

[0097] The atmospheric temperature of the atmosphere for spraying can be set to 50°C or less, for example. Spraying is preferably performed with the atmospheric temperature set to 50°C or less and the substrate temperature set to 300°C or less. From the viewpoint of promoting the crystallization of zinc oxide in the zinc oxide coating, the atmospheric temperature for spraying is preferably above 0°C and below 40°C, and the substrate temperature is preferably above 100°C and below 250°C. Furthermore, "coating-drying-heating" is set as one cycle, and the number of cycles can be set to one or more than two times. By repeating it more than twice, a thick film of the zinc oxide coating can be sought. In addition, the coating amount of the coating liquid can be adjusted according to the concentration of the above-mentioned organic zinc compound of the coating liquid, the specifications of the spraying device used, the film thickness of the zinc oxide coating to be formed, etc.

[0098] Example

[0099] Hereinafter, the present invention will be described based on examples, but the present invention is not limited to the embodiments shown in the examples.

[0100] The physical property values ​​of the zinc oxide film described below were measured using the following measuring apparatus and under the following measuring conditions.

[0101] The surface area increase rate Sdr was measured using VK-9500 / VK-9510 manufactured by KEYENCE Corporation as a laser microscope under the following measurement conditions.

[0102] Measurement conditions: lens 20 times (viewing angle: 700μm×530μm)

[0103] Step size in Z direction: 0.01 μm

[0104] The film thickness was measured using a stylus-type surface profile measuring device (DektakXT-S manufactured by BRUKER-NANO Corporation).

[0105] The transmittance was measured using a spectrophotometer manufactured by JASCO Corporation to determine the transmittance at a wavelength of 550 nm.

[0106] The spraying device A described below is rCoater (movable nozzle type) manufactured by Asahi Sunac Co., Ltd. The spraying device B described below is a spraying device (fixed nozzle type) described in Japanese Patent Application Laid-Open No. 2011-170979.

[0107] In Table 1, the "Spray Pressure" column records the spray pressure set when using the spray device A. Since the spray device B is a spray device that does not have a spray pressure control unit and controls the flow rate of the accompanying gas during spraying, in Table 1, the "Spray Pressure" column of Example 3 using the spray device B is recorded as "N / A" (Not available).

[0108] [Example 1]

[0109] <Preparation of coating liquid A>

[0110] 48.25 g of diethyl zinc was added to 296.40 g of xylene, and the mixture was stirred sufficiently to obtain a coating liquid A.

[0111] The coating liquid A was prepared in a nitrogen atmosphere, and the solvent (xylene) was dehydrated and degassed before use.

[0112] <Application of coating liquid>

[0113] As a substrate, a glass substrate (EAGLE XG manufactured by CORNING) with a size of 5 cm×5 cm was placed on a substrate holder, heated to a substrate temperature of 200°C, and then sprayed with 1 mL of coating liquid A (number of spraying times: 1 time) using a spray device A (spray pressure: refer to Table 1) at atmospheric pressure in an air containing water at an atmosphere temperature of 25°C and a relative humidity of 50%.

[0114] As described above, an article having a zinc oxide coating on one surface of a substrate is obtained.

[0115] [Example 2]

[0116] Except that the relative humidity of the atmosphere for spraying was changed as shown in Table 1, an article having a zinc oxide coating on one surface of a substrate was obtained by the method described in Example 1.

[0117] [Example 3]

[0118] <Preparation of coating liquid B>

[0119] 18.14 g of diethyl zinc was added to 163.08 g of diisopropyl ether, and the mixture was stirred sufficiently to obtain a coating liquid B.

[0120] The coating liquid B was prepared under a nitrogen atmosphere, and the solvent (diisopropyl ether) was dehydrated and degassed before use.

[0121] <Application of coating liquid>

[0122] A glass substrate (EAGLE XG manufactured by CORNING) with a size of 5 cm×5 cm was set on a substrate holder as a substrate, and after heating to a substrate temperature of 200°C, 16 mL of coating liquid B was sprayed using a spray device B under atmospheric pressure in an atmosphere temperature of 25°C and a relative humidity of 80% in the presence of water (number of spraying times: 1 time).

[0123] As described above, an article having a zinc oxide coating on one surface of a substrate is obtained.

[0124] [Example 4]

[0125] <Preparation of coating liquid C>

[0126] 30.05 g of diethyl zinc was added to 270.45 g of xylene, and the mixture was stirred sufficiently to obtain a coating liquid C.

[0127] The coating liquid C was prepared in a nitrogen atmosphere, and the solvent (xylene) was dehydrated and degassed before use.

[0128] <Application of coating liquid>

[0129] A glass substrate (EAGLE XG manufactured by CORNING Co.) with a size of 5 cm×5 cm was placed on a substrate holder as a substrate, and after heating to a substrate temperature of 200°C, 1 mL of coating liquid C was sprayed once using a spraying device A (spraying pressure: see Table 1) in an atmosphere with a temperature of 25°C and a relative humidity of 50% in the presence of water under atmospheric pressure. This spraying was repeated 5 times in total, and a total of 5 mL of coating liquid C was sprayed.

[0130] As described above, an article having a zinc oxide coating on one surface of a substrate is obtained.

[0131] [Example 5]

[0132] Except that the relative humidity of the atmosphere for spraying was changed as shown in Table 1, an article having a zinc oxide coating on one surface of a substrate was obtained by the method described in Example 4.

[0133] [Example 6]

[0134] A glass substrate (EAGLE XG manufactured by CORNING) with a size of 5 cm×5 cm was placed on a substrate holder as a substrate, and after heating to a substrate temperature of 200°C, 1 mL of the coating liquid C prepared as described above was sprayed once on one surface of the substrate using a spraying device A (spraying pressure: refer to Table 1) in an atmosphere with a temperature of 25°C and a relative humidity of water shown in Table 1 under atmospheric pressure. This spraying was repeated 8 times in total, and a total of 8 mL of the coating liquid C was sprayed.

[0135] As described above, an article having a zinc oxide coating on one surface of a substrate is obtained.

[0136] [Comparative Example 1]

[0137] An article having a zinc oxide coating on one surface of a substrate was obtained by the method described in Example 6 except that the coating liquid A prepared as described above was used.

[0138] [Comparative Example 2]

[0139] An article having a zinc oxide coating on one surface of a substrate was obtained by the method described in Example 4 except that the relative humidity of the spraying atmosphere was changed as shown in Table 1 and the spray pressure was set to the value shown in Table 1.

[0140] 〔Antibacterial test〕

[0141] The Japan Food Analysis Center conducted an antibacterial test on each of the articles of Examples 1 to 6 and Comparative Example 2. The antibacterial test was performed by the following method.

[0142] Using Escherichia coli and Staphylococcus aureus as test bacteria, the antimicrobial activity value of the surface of the zinc oxide coating of each article (ie, the outermost surface of the article) was determined by the method described above in accordance with JIS Z2801:2010.

[0143] In Examples 1, 2, and 4, antibacterial tests were also conducted using methicillin-resistant Staphylococcus aureus as test bacteria according to the method described above in accordance with JIS Z 2801: 2010. In the antibacterial tests, the glass substrate (without film) was used as an unprocessed product.

[0144] In Example 4, an antibacterial test was also conducted using Klebsiella pneumoniae, Moraxella, and Pseudomonas aeruginosa as test bacteria according to the method described above in accordance with JIS Z 2801: 2010. In the antibacterial test, the glass substrate (without film) was used as an unprocessed product.

[0145] As shown in Table 2, in any of Examples 1 to 6, as the test results of the antibacterial test, antibacterial activity values ​​of 2.0 or more, which are considered to have antibacterial activity, were obtained for Escherichia coli and Staphylococcus aureus. In Comparative Example 2, the antibacterial activity values ​​for Escherichia coli and Staphylococcus aureus were also 2.0 or more.

[0146] In Example 1, Example 2, and Example 4, antibacterial activity values ​​of 2.0 or more, which are considered to have antibacterial activity, were also obtained against methicillin-resistant Staphylococcus aureus.

[0147] In Example 4, antibacterial activity values ​​of 2.0 or more, which are considered to have antibacterial activity, were also obtained for Klebsiella pneumoniae, Moraxella, and Pseudomonas aeruginosa.

[0148] In addition, regarding Comparative Example 1, since the transmittance of the zinc oxide coating at a wavelength of 550 nm was low and the transparency was poor, the antibacterial test was not carried out.

[0149] The above results are shown in the following table.

[0150] [Table 1]

[0151]

[0152] [Table 2]

[0153]

[0154] [Antiviral test]

[0155] The antiviral test of the article of Example 4 was carried out at the Japan Textile Quality Technology Center (Kobe Test Center). The antiviral test against the mutant strain of SARS-CoV-2 (Omicron strain) was carried out by the following method according to ISO 21702. As an unprocessed product, the above-mentioned glass substrate (without coating) was used.

[0156] In Example 4, as the test results of the antiviral test, an antiviral activity value of 2.0 or more (specifically, "≥4.0"), which is considered to have antiviral activity, was obtained for the SARS-COV-2 mutant strain (Omicron strain).

[0157] (1) Place the test sample (articles and unprocessed products of Example 4) at the bottom of a sterilized culture dish and inoculate 0.4 mL to prepare 1 to 5 × 10 7 The article of Example 4 was placed on the bottom of a culture dish with the surface coated with zinc oxide facing upward.

[0158] (2) Cover with a sealing film (40 mm × 40 mm) and press gently to allow the test virus suspension to spread throughout the film.

[0159] (3) Cover the culture dish with a lid.

[0160] (4) After standing at an action temperature of 25°C for 24 hours and a relative humidity of 90% or higher, 10 mL of an eluent (a solution prepared by diluting SCDLP 10-fold (volume basis) with DMEM (Dulbecco's Modified Eagle's Medium) containing 2% by mass FBS (Fetal Bovine Serum)) was added to each test sample.

[0161] (5) Rub the surface of each test sample and the sealing film to wash out the virus.

[0162] (6) The virus infection titer in the eluate was measured by plaque assay. VeroE6 / TMPRSS2 (cells derived from African green monkey kidney) was used as the host cell.

[0163] (7) The above steps (1) to (6) are repeated three times to calculate the virus infection titer.

[0164] 〔Deodorization effect test〕

[0165] The deodorization effect test of the article of Example 4 was carried out at the Japan Food Analysis Center. The deodorization effect test was carried out on three malodorous gases, hydrogen sulfide, methyl mercaptan and isovaleric acid, by the following method. The unit "ppm" described below is based on volume.

[0166] As a sample, the article of Example 4 was placed in an odor bag (made of polyvinyl fluoride), heat-sealed and sealed, 3 L of air was enclosed, and the test target gas was added so that the initial gas concentration reached the set gas concentration.

[0167] The odor bag was left at room temperature, and the concentration of the test target gas in the odor bag was measured by a gas detection tube at each elapsed time. As a control, the glass substrate (without film) was used, and a blank test without using a sample or a control was also performed.

[0168] As a result, in the test using the article of Example 4 as a sample, as shown in Table 3, when hydrogen sulfide gas was used as the test target gas, the initial gas concentration of hydrogen sulfide gas was about 20 ppm and reached a concentration of 8 ppm (removal rate 60%) after 24 hours.

[0169] When methyl mercaptan gas was used as the test target gas, as shown in Table 4, the initial gas concentration of methyl mercaptan gas was about 8.0 ppm, but the concentration reached 2.1 ppm (removal rate 74%) after 24 hours.

[0170] Furthermore, when isovaleric acid gas was used as the test target gas, as shown in Table 5, the isovaleric acid gas with an initial gas concentration of about 15 ppm reached a concentration of 2.4 ppm (removal rate 84%) after 24 hours.

[0171] [Table 3]

[0172]

[0173] Initial gas concentration: about 20ppm

[0174] [Table 4]

[0175]

[0176] Initial gas concentration: about 8.0ppm

[0177] [Table 5]

[0178]

[0179] Initial gas concentration: about 15ppm

[0180] Based on the above results, it was confirmed that the article of Example 4 was able to effectively deodorize various malodorous gases compared with the control sample and the blank test sample.

[0181] The article related to one embodiment of the present invention can be used as various articles requiring antibacterial performance and / or antiviral performance in medical institutions, commercial facilities, public facilities, food / pharmaceutical factories, research institutions, nursing sites, cooking / food-related sites, transportation institutions, etc. In addition, the article related to one embodiment of the present invention can be used as a deodorizing material.

Claims

1. An article having a zinc oxide coating on a substrate, wherein: The surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 13.00% or less, and the antimicrobial activity value (based on JIS Z 2801:2010) is 2.0 or more.

2. The article according to claim 1, wherein The antiviral activity value (based on ISO 21702) measured on the surface of the zinc oxide coating is 2.0 or more.

3. The article according to claim 1, wherein The zinc oxide film has a thickness of 50 nm to 1000 nm.

4. The article according to claim 1, wherein The transmittance of the zinc oxide film at a wavelength of 550 nm is 80.0% or more.

5. The article according to claim 1, wherein A surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 9.00% or less.

6. The article of claim 1, wherein: The zinc oxide coating has a film thickness of 50 nm to 1000 nm, and a transmittance of 80.0% or more at a wavelength of 550 nm.

7. The article according to claim 6, wherein A surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 9.00% or less.

8. The article of claim 1, wherein: The antiviral activity value (according to ISO 21702) measured on the surface of the zinc oxide coating is 2.0 or more, The zinc oxide coating has a thickness of 50 nm or more and 1000 nm or less. The transmittance of the zinc oxide film at a wavelength of 550 nm is 80.0% or more.

9. The article according to claim 8, wherein A surface area increase rate Sdr measured on the surface of the zinc oxide coating is 2.00% or more and 9.00% or less.

10. The article according to any one of claims 1 to 9, which is a deodorizing material.

11. The method for producing an article according to any one of claims 1 to 9, comprising: The zinc oxide coating is formed by applying a coating liquid containing an organic zinc compound represented by the following formula (1) in an atmosphere in the presence of water. Formula (1): R 1 -Zn-R 2 In formula (1), R 1 and R 2 Each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms.

12. The manufacturing method according to claim 11, wherein: The coating was performed under atmospheric pressure.

13. The manufacturing method according to claim 11, wherein: The organic zinc compound represented by the formula (1) is diethyl zinc.

14. A deodorization method, comprising: The article according to claim 10 is placed in an atmosphere containing a deodorizing target gas.

15. The deodorization method according to claim 14, wherein: The deodorization target gas is selected from hydrogen sulfide gas, methyl mercaptan gas and isovaleric acid gas.

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