Device, and antimicrobial method and food preservation method using the same.

Abstract

The present invention aims to provide a device that can safely and efficiently obtain an antibacterial effect in the coexistence of platinum group element-supported porous silica and alcohol. [Solution] A device comprising a porous silica-containing portion supporting platinum group elements and a gaseous alcohol source, wherein the porous silica-containing portion supporting platinum group elements and the gaseous alcohol source are arranged adjacent to each other such that the gaseous alcohol originating from the gaseous alcohol source permeates through the porous silica-containing portion supporting platinum group elements and comes into contact with the platinum group elements.

Description

[Technical Field]

[0001] The present invention relates to a device comprising a porous silica-containing portion supporting platinum group elements and a gaseous alcohol source arranged adjacent to each other under predetermined conditions, and to an antimicrobial method using the same. [Background technology]

[0002] The antimicrobial effects of alcohol on microorganisms (inhibition of growth, sterilization, etc.) have been known for some time, and alcohol is used in a wide variety of forms as an antimicrobial agent. For example, alcohol vaporizers (also called alcohol volatile agents, etc.), which are made by impregnating some kind of medium with alcohol, utilize this antimicrobial effect of alcohol. The alcohol vapor generated when alcohol evaporates from the medium diffuses into a designated space, exerting a broad antimicrobial effect. Generally, it is said that an antimicrobial effect can be obtained by maintaining an alcohol concentration of 0.3 Vol% or higher in the space (Non-Patent Literature 1), and the amount of alcohol is adjusted so that this concentration is achieved or maintained.

[0003] Furthermore, porous silica supported with platinum group metal particles is known to be usable as an antibacterial porous material and an antifungal porous material (Patent Documents 1 and 2). When these materials were added to bacterial solutions and stored, it was confirmed that they exhibited high antibacterial and antifungal properties against Escherichia coli, Staphylococcus aureus, and Penicillium. In addition, it has been confirmed that storing this antifungal porous material together with food suppressed the growth of mold in the food (Non-Patent Document 2).

[0004] Furthermore, it has been confirmed that by allowing platinum group element-supported porous silica and alcohol to act together, a significantly higher antibacterial effect was obtained compared to the effect expected from the antibacterial effects of platinum group element-supported porous silica and alcohol individually (Patent Document 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-136655 [Patent Document 2] Japanese Patent Publication No. 2019-137637 [Patent Document 3] WO2024 / 181494 publication [Non-patent literature]

[0006] [Non-Patent Document 1] Sanko Shoji Co., Ltd. website, "Food Preservation Using Alcohol Vaporizing Agents" (https: / / www.sanko-shoji.jp / lecture / cn8 / pg128380.html), as of September 12, 2024. [Non-Patent Document 2] Furuya Metals Co., Ltd. website, "FT-eco catalyst test video" (https: / / www.furuyametals.co.jp / technology / r_and_d.html), as of September 12, 2024. [Overview of the project] [Problems that the invention aims to solve]

[0007] The inventors have found that when obtaining an antibacterial effect by coexisting porous silica supported with platinum group elements and alcohol, simply placing the porous silica and alcohol in a space may not be sufficient to obtain an antibacterial effect. Furthermore, we found that in order to obtain an antibacterial effect by coexisting platinum group element-supported porous silica with alcohol, it may be necessary to fill the entire space with alcohol, and this may lead to problems such as harmful effects on the human body and odor caused by the alcohol.

[0008] Therefore, the present invention aims to provide a device that can safely and efficiently obtain an antibacterial effect in the coexistence of platinum group element-supported porous silica and alcohol. [Means for solving the problem]

[0009] As a result of diligent research to solve the above problems, the present inventors have found that by arranging a porous silica-containing portion supporting platinum group elements and a gaseous alcohol source adjacent to each other, such that the gaseous alcohol from the gaseous alcohol source permeates through the porous silica-containing portion supporting platinum group elements and comes into contact with the platinum group elements, it is possible to obtain an antibacterial effect safely and efficiently, and that it is not necessary to fill the entire space with alcohol.

[0010] This invention is based on these novel findings and encompasses the following inventions. [1] A device comprising a porous silica-containing portion supporting platinum group elements and a gaseous alcohol source, wherein the porous silica-containing portion supporting platinum group elements and the gaseous alcohol source are arranged adjacent to each other such that gaseous alcohol originating from the gaseous alcohol source permeates through the porous silica-containing portion supporting platinum group elements and comes into contact with the platinum group elements. [2] The device of [1] having a filter between the platinum group element-supported porous silica-containing portion and the gaseous alcohol source through which gaseous alcohol permeates and is slowly released. [3] The device according to [1] or [2], wherein the platinum group element-supported porous silica-containing portion has a structure in which the platinum group element-supported porous silica is fixed to a porous member. [4] The gaseous alcohol source is a device having a structure in which liquid alcohol is impregnated into a medium, or a structure in which liquid alcohol is contained in a container. [1] to [3] [5] Any of the devices [1] to [4] having an air-permeable filter on the side of the platinum group element-supported porous silica-containing portion opposite to the side adjacent to the gaseous alcohol source. [6] Any of the devices [1] to [5] of the gaseous alcohol source having a structure on the side opposite to the side adjacent to the platinum group element-supported porous silica-containing portion that can block the permeation of air. [7] The device according to any one of [1] to [6], wherein the platinum group element-supported porous silica-containing part and the gaseous alcohol generation source have a laminated structure. [8] The device according to any one of [1] to [7], wherein the platinum group element is platinum. [9] The device according to any one of [1] to [8], wherein the alcohol is ethanol.

[10] An antibacterial method using the device according to any one of [1] to [9].

[11] The antibacterial method according to

[10] , wherein at least one antibacterial component selected from aldehyde, carboxylic acid, and peracetic acid is released from the device.

[12] A method for preserving food using the device according to any one of [1] to [9]. [Advantages of the Invention]

[0011] According to the present invention, it is possible to provide a device capable of obtaining a safe and efficient antibacterial effect in the coexistence of a platinum group element-supported porous silica and an alcohol. [Brief Description of the Drawings]

[0012] [Figure 1] FIG. 1 shows a schematic cross-sectional view of a device 10 in which a platinum group element-supported porous silica-containing part 11 and a gaseous alcohol generation source 12 having the form of an alcohol evaporant have a laminated structure. [Figure 2] FIG. 2 shows a schematic cross-sectional view of a device 20 in which a platinum group element-supported porous silica-containing part 21 and a gaseous alcohol generation source 22 having the form of a container containing a liquid alcohol 26 have a laminated structure. [Modes for Carrying Out the Invention]

[0013] 1. Platinum Group Element-Supported Porous Silica In the present invention, "platinum group element-supported porous silica" means porous silica on which platinum group elements are supported in the form of metals and / or compounds. The platinum group elements may be held in granular form on the surface of the porous silica, or a portion may penetrate into the pore walls of the porous silica. Furthermore, at least a portion of the platinum group elements may be bonded to silicon atoms of the porous silica directly or via other elements, or they may exist in a form bonded to other elements or compounds.

[0014] "Platinum group elements" are elements located in groups 8-10 of the 5th and 6th periods of the periodic table. Specifically, platinum group elements include platinum, palladium, rhodium, iridium, ruthenium, or osmium. In this specification, the platinum group elements supported by the platinum group element-supported porous silica may be one or more. Among these, it is preferable that the platinum group element supported by the porous silica is platinum.

[0015] In the present invention, the porous silica supporting platinum group elements preferably satisfies the following formula (1). A / (A+B)×100≧5% ... Equation (1) In equation (1), A represents the number of platinum group elements supported on porous silica in the form of hydroxides, and B represents the number of platinum group elements supported on porous silica in the form of metals.

[0016] Because the platinum group element-supported porous silica satisfies formula (1), it easily exhibits excellent antibacterial effects when in contact with alcohol.

[0017] In the oxidation reaction of alcohols, the alcohol is oxidized on the platinum surface, and the hydroxyl groups sequentially activate carbon monoxide and oxygen. Therefore, it is thought that the oxidation reaction proceeds more favorably when the proportion of platinum group elements present in hydroxide form is 5% or more in porous silica supported with platinum group elements.

[0018] Incidentally, the number of platinum elements supported on porous silica in the state of metal and the number of platinum elements supported on porous silica in the state of hydroxide can be measured by a conventionally known elemental analysis method. For example, in one embodiment, the number of platinum elements supported on platinum group element-supported porous silica and the number of platinum elements supported on porous silica in the state of hydroxide are analyzed and measured using X-ray photoelectron spectroscopy under the following conditions. The content of platinum hydroxide (atm%) is calculated from the area% of the obtained photoelectron spectrum intensity.

[0019] <X-ray photoelectron spectroscopy> Apparatus: KRATOS ULTRA2 X-ray source: Monochromatic Al-Kα, output 15 kV - 75 W or 225 W (5 mA or 15 mA) Charge neutralization: Filament current, Filament bias, Charge balance = 0.43 V, 1 V, 4 V Spectrometer system: Pass energy Wide spectrum 160 eV, Narrow spectrum 20 eV (O , 2p ,

[0021] , , , ,

[0020] , Si 2p , Pt 4f ), 80 eV (C 1s ) Measurement area (Collimation, lens): 700 μm × 300 μm (Slot, Hybrid) Take-off angle (from the surface): 90° Energy correction: Si 2p = 103.5 eV

[0020] Incidentally, in this specification, the platinum group elements supported in the state of metal may be referred to as platinum group metals, and the platinum group elements supported in the state of hydroxide may be referred to as platinum group element-containing hydroxides.

[0021] As shown in formula (1) above, A / (A+B)×100 is preferably 5% or more, more preferably 10% or more, and more preferably 15% or more, and even more preferably 20% or more. From the viewpoint of ensuring sufficient metallic platinum, it is preferably 50% or less, more preferably 40% or less, and most preferably 30% or less.

[0022] Furthermore, in the present invention, the porous silica supporting platinum group elements may have multiple types of platinum group elements supported on it. Moreover, when a platinum group metal and a platinum group element-containing hydroxide are supported on the porous silica supporting platinum group elements, the types of platinum group elements supported in metallic form and those supported in hydroxide form may be the same or different. However, as described above, the platinum group element is preferably a platinum element, and in this case, it is particularly preferable that the platinum group elements A and B in formula (1) are platinum elements and that the above formula (1) is satisfied.

[0023] The proportion of platinum group elements in 100 parts by mass of porous silica supporting platinum group elements is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, from the viewpoint of improving contact efficiency with alcohol, while from the viewpoint of durability, it is preferably 5 parts by mass or less, and more preferably 4 parts by mass or less.

[0024] While there are no particular restrictions on the average particle size of platinum group element-supported porous silica, it is preferably 1 μm or larger, more preferably 3 μm or larger, and particularly preferably 5 μm or larger, in order to suppress particle aggregation. On the other hand, in order to maintain a certain surface area of ​​the particles, it is preferably 1,000 μm or smaller, more preferably 800 μm or smaller, and particularly preferably 600 μm or smaller. The average particle size of platinum group element-supported porous silica can be measured using a laser diffraction particle size distribution analyzer.

[0025] The pore volume of the platinum group element-supported porous silica is not particularly limited, but from the viewpoint of improving the contact efficiency with alcohol, it is preferably 0.3 mL / g or more, more preferably 0.4 mL / g or more, and particularly preferably 0.5 mL / g or more. On the other hand, from the viewpoint of ease of production, it is preferably 1.6 mL / g or less, more preferably 1.5 mL / g or less, and particularly preferably 1.3 mL / g or less. Also, the specific surface area of the platinum group element-supported porous silica is not particularly limited, but it is preferably 200 m 2 / g or more. On the other hand, it is preferably 1000 m 2 / g or less, more preferably 800 m 2 / g or less, and particularly preferably 700 m 2 / g or less. The values of these pore volume and specific surface area can be measured by the BET method using nitrogen gas adsorption and desorption.

[0026] In the present invention, the platinum group element-supported porous silica has a most frequent diameter (Dmax) of less than 20 nm on a graph obtained by plotting the differential nitrogen gas adsorption amount (ΔV / Δ(log d); V is the nitrogen gas adsorption volume) against the pore diameter d (nm) from the isothermal desorption curve measured by the nitrogen gas adsorption and desorption method, i.e., according to the BJH method described in E. P. Barrett, L. G. Joyner, P. H. Haklenda, J. Amer. Chem. Soc., vol. 73, 373 (1951). From the viewpoint that the reactant alcohol can efficiently penetrate into the pores and the product containing the antibacterial component can be efficiently diffused after the reaction, the lower limit of the most frequent diameter (Dmax) is preferably 2.0 nm or more, more preferably 3.0 nm or more, and most preferably 3.5 nm or more.

[0027] In the present invention, it is preferable that the total volume of pores in the platinum group element-supported porous silica within ±20% of the above-mentioned mode diameter (Dmax) is 40% or more of the total volume of all pores, and more preferably 50% or more. Furthermore, it is preferable that the total volume of pores within ±20% of the above-mentioned mode diameter (Dmax) is 90% or less of the total pore volume. This means that the diameters of the pores in the platinum group element-supported porous silica are uniform around the mode diameter (Dmax).

[0028] The most frequent pore diameter (Dmax) of platinum group element-supported porous silica is 2.0 nm or greater, as described above, and the volume of pores within ±20% of Dmax is 90% or less of the total pore volume, which is considered favorable for the diffusion of reactants and products. The proportion of pore volume within ±20% of Dmax is calculated from the isothermal desorption curve measured by nitrogen gas adsorption / desorption, the pore distribution curve calculated by the BJH method described in EP Barrett, LG Joyner, PH Haklenda, J. Amer. Chem. Soc., vol. 73, 373 (1951), and the ratio of the height from the baseline to the most frequent diameter (Dmax) and the height from the baseline to (W) when the width (W) is taken as a range of ±20% centered on the most frequent diameter (Dmax), on a graph plotting the differential nitrogen gas adsorption amount (ΔV / Δ(logd); V is the nitrogen gas adsorption volume) against the pore diameter d (nm).

[0029] In the present invention, the porous silica supporting platinum group elements preferably has a differential pore volume ΔV / Δ(logd) at the most frequent diameter (Dmax) calculated by the BJH method described above, which is 2 to 20 mL / g, and particularly preferably 3 to 12 mL / g (wherein d is the pore diameter (nm) and V is the nitrogen gas adsorption volume). A material in which the differential pore volume ΔV / Δ(logd) falls within the above range can be said to have an extremely large absolute amount of pores aligned around the most frequent diameter (Dmax).

[0030] Furthermore, in the present invention, in addition to the above-mentioned pore structure characteristics, it is preferable that the platinum group element-supported porous silica is amorphous in its three-dimensional structure, that is, that no crystalline structure is observed, and in particular, it is preferable that it has a three-dimensional pore structure. This means that when the platinum group element-supported porous silica is analyzed by X-ray diffraction, substantially no crystalline peaks are observed. It should be noted that amorphous porous silica is extremely productive compared to crystalline porous silica in this specification.

[0031] The method for producing platinum group element-supported porous silica in the present invention is not particularly limited, but it is preferably obtained by reducing a mixture of a platinum group element raw material, such as a platinum element-containing compound or an organic complex containing a platinum group element, and porous silica. For example, platinum group element-supported porous silica can be obtained by preparing an aqueous solution containing a platinum group element raw material, impregnating porous silica with the aqueous solution, drying, and then performing a reduction treatment. Examples of platinum group element-containing compounds include platinum group element hydrochlorides, nitrates, and sulfates.

[0032] In the present invention, the platinum group element-supported porous silica typically has a specific amount of platinum group element-containing hydroxide supported on it. However, the amount of hydroxide can be adjusted by the amount of silanol groups inside the porous silica on which the platinum group element is supported. That is, to increase the amount of platinum group element-containing hydroxide supported in the resulting platinum group-supported porous silica, a porous silica with a large amount of internal silanol groups should be used. On the other hand, to decrease the amount of platinum group element-containing hydroxide supported in the resulting platinum group-supported porous silica, a porous silica with a small amount of internal silanol groups should be used. The amount of silanol groups inside the porous silica can be adjusted by the synthesis conditions during the production of the porous silica. In the case of the production conditions for porous silica described in Japanese Patent Application Publication No. 2017-23889, an organic raw material is used as a template, and after the condensation polymerization reaction, the organic raw material must be removed by firing at a high temperature of 400 to 800°C. Therefore, it is difficult to obtain platinum group element-supported porous silica that satisfies formula (1), such as the platinum group element-supported porous silica of this embodiment.

[0033] There are no particular restrictions on the BET specific surface area, pore volume, and particle size of porous silica before the platinum group elements are supported; they can be appropriately selected to obtain the desired platinum group element-supported porous silica. Therefore, these preferred ranges are the same as those listed above for platinum group element-supported porous silica.

[0034] There are no particular limitations on the method for producing porous silica. For example, silica hydrogel obtained by hydrolyzing alkali silicate salts, or silica hydrogel obtained by hydrolyzing silicon alkoxides, can be produced by applying a hydrothermal treatment method without aging. Preferably, the method involves hydrolyzing silicon alkoxides.

[0035] Examples of silicon alkoxides include tri- or tetraalkoxysilanes or oligomers thereof having a lower alkyl group with 1 to 4 carbon atoms, such as trimethoxysilane, tetramethoxysilane, triethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, but tetramethoxysilane, tetraethoxysilane, and their oligomers are preferred. Since these silicon alkoxides can be easily purified by distillation, they are suitable as raw materials for high-purity silica gel. The total content of metal impurities in the silicon alkoxide is preferably 100 ppm or less, and more preferably 10 ppm or less. The content of metal impurities can be measured by the same method as for measuring impurities in porous silica.

[0036] The hydrolysis of silicon alkoxide is carried out using 2 to 20 moles, preferably 3 to 10 moles, and particularly preferably 4 to 8 moles, of water per mole of silicon alkoxide. Hydrolysis of silicon alkoxide produces silica hydrogel and alcohol. This hydrolysis reaction is usually carried out at room temperature to around 100°C, but it can also be carried out at higher temperatures by maintaining the liquid phase under pressure. The reaction time depends on the reaction solution composition (type of silicon alkoxide and molar ratio with water) and the reaction temperature, and the time until gelation occurs varies, so it cannot be specified in general terms. The reaction time is usually such that the fracture stress of the hydrogel does not exceed 6 MPa. Hydrolysis can be accelerated by adding acids, alkalis, salts, etc., as catalysts to the reaction system. However, as described later, the use of such additives causes maturation of the resulting hydrogel, so it is preferable not to use them in the production of porous silica.

[0037] In the hydrolysis reaction of the silicon alkoxide described above, the silicon alkoxide hydrolyzes to produce a silicate, which then undergoes a condensation reaction, increasing the viscosity of the reaction solution and ultimately gelling to form a silica hydrogel. To produce porous silica, it is preferable to immediately perform hydrothermal treatment without substantial aging, so as not to increase the hardness of the silica hydrogel produced by the above hydrolysis.

[0038] As mentioned above, immediately performing hydrothermal treatment on the silica hydrogel produced by hydrolysis, without substantial maturation, means that the soft state of the silica hydrogel immediately after its formation is maintained while it is subjected to the subsequent hydrothermal treatment. Adding acids, alkalis, salts, etc., to the silicon alkoxide hydrolysis reaction system, or making the temperature of the hydrolysis reaction too severe, is undesirable because it promotes the maturation of the hydrogel. Furthermore, it is preferable not to apply excessive temperature or time during post-treatment such as washing, drying, and standing after hydrolysis.

[0039] The conditions for the hydrothermal treatment are that the water can be in either liquid or gaseous state, and may be diluted with a solvent or other gas, but liquid water is preferably used. To the silica hydrogel, water is usually added in an amount of 0.1 to 10 times, preferably 0.5 to 5 times, and particularly preferably 1 to 3 times, to form a slurry, and the treatment is carried out at a temperature of usually 40 to 250°C, preferably 50 to 200°C, for usually 0.1 to 100 hours, preferably 1 to 10 hours. The water used in the hydrothermal treatment may contain lower alcohols, methanol, ethanol, propanol, etc. This hydrothermal treatment method can also be applied to materials in which porous silica is formed in a film or layer form on a substrate such as particles, a substrate, or a tube, for the purpose of creating a membrane reactor or the like.

[0040] Under the above hydrothermal treatment conditions, increasing the temperature tends to increase the pore diameter and pore volume of the resulting porous silica. Furthermore, with increasing treatment time, the specific surface area of ​​the resulting porous silica tends to reach a maximum once and then gradually decrease. Based on these trends, it is necessary to appropriately select the conditions according to the desired physical properties. However, since the purpose of hydrothermal treatment is to change the physical properties of porous silica, it is generally preferable to use higher temperature conditions than those for the hydrolysis reaction described above.

[0041] Setting the temperature and time of the hydrothermal treatment within the above range makes it easier to obtain porous silica according to the present invention. Conversely, for example, if the hydrothermal treatment temperature is too high, the pore diameter and pore volume of the porous silica become too large, and the pore distribution also becomes broader. Conversely, if the hydrothermal treatment temperature is too low, the resulting porous silica tends to have a low degree of crosslinking and poor thermal stability.

[0042] Furthermore, performing the hydrothermal treatment in ammonia water yields similar results at lower temperatures than when performing it in pure water. Also, compared to treatment in pure water, hydrothermal treatment in ammonia water generally results in more hydrophobic porous silica, and hydrophobicity is particularly high when performed at relatively high temperatures, typically 30-250°C, preferably 40-200°C. The ammonia concentration in the ammonia water used here is preferably 0.001-10 vol%, and particularly preferably 0.005-5 vol%.

[0043] The hydrothermally treated silica hydrogel is usually dried at 40-200°C, preferably 60-120°C. The drying method is not particularly limited and can be batch or continuous, and can be dried under atmospheric pressure or reduced pressure. If carbon content derived from the raw material silicon alkoxide is present, it can be removed by calcination, usually at 400-600°C. Furthermore, calcination may be performed at temperatures up to 900°C to control the surface condition. In addition, pulverization and classification may be performed as needed.

[0044] Porous silica with a crystalline structure tends to have poor thermal stability in water. When silicon alkoxide is hydrolyzed in the presence of a template such as a surfactant used to form pores in the gel, the gel easily becomes one that contains a crystalline structure. Furthermore, since it is necessary to calcine at high temperatures to remove the template after the reaction process, the amount of silanol groups inside decreases, and the proportion of platinum group element-containing hydroxides in the resulting platinum group element-supported porous silica tends to decrease. Therefore, in the present invention, it is preferable to perform hydrolysis in the absence of a template such as a surfactant, that is, under conditions where the amount of these is not sufficient to exert their function as a template.

[0045] 2. Platinum group element-supported porous silica-containing portion In the present invention, the "platinum group element-supported porous silica-containing portion" is a structure that holds platinum group element-supported porous silica, allowing gaseous alcohol originating from a gaseous alcohol source to permeate through it, thereby generating and releasing antibacterial components through a reaction between the platinum group element and alcohol, as described later. As long as the platinum group element-supported porous silica-containing portion has the above function, there are no structural limitations, and it can take any form. For example, it may be a structure in which the platinum group element-supported porous silica is fixed to a porous material (nonwoven fabric, porous silica, diatomaceous earth, pulp, paper scraps, felt, cellulose, absorbent cotton, gel, starch, cyclodextrin, vermiculite, activated carbon, etc.), or a structure in which the platinum group element-supported porous silica is contained in a packaging material that allows gaseous alcohol and air to permeate. Such packaging materials can be made of cloth, nonwoven fabric, paper, resin film, etc. In the present invention, the platinum group element-supported porous silica-containing portion is particularly preferably a structure in which the platinum group element-supported porous silica is fixed to a porous member. By fixing the platinum group element-supported porous silica to a porous member, it is possible to uniformly disperse and arrange the platinum group element-supported porous silica, and it is possible to efficiently contact gaseous alcohol to generate antibacterial components. Nonwoven fabric is particularly preferably used as the porous member for fixing the platinum group element-supported porous silica-containing portion.

[0046] 3. Sources of gaseous alcohol In the present invention, "alcohol" refers to an organic compound having a hydroxyl group, and may be a monoalcohol, a diol, or a polyhydric alcohol. Among these, ethanol is particularly preferred in the present invention, from the viewpoint of use in the vicinity of food, as it is commonly used as a food or food additive.

[0047] In the present invention, a "gaseous alcohol source" is a structure that generates gaseous alcohol by volatilizing, evaporating, and / or spraying alcohol. As long as the gaseous alcohol source has the function described, there are no structural limitations, and it can take any form. For example, a mechanism for volatilizing alcohol can be an alcohol vaporizer or a container for liquid alcohol. In the present invention, an "alcohol vaporizer" refers to a medium impregnated with liquid alcohol, which can gradually vaporize gaseous alcohol and provide sustained release. The medium for impregnation with alcohol can be any medium that can support liquid alcohol and gradually vaporize gaseous alcohol, and is not particularly limited, but examples include nonwoven fabric, porous silica, diatomaceous earth, pulp, paper scraps, felt, cellulose, absorbent cotton, gel, starch, cyclodextrin, vermiculite, activated carbon, etc., and in the present invention, nonwoven fabric can be used particularly suitably. Furthermore, as long as the container for holding the liquid alcohol is capable of holding liquid alcohol, there are no structural restrictions, and it can take any form. For example, a container made of metal, resin, glass, etc., can be used. Compared to an alcohol vaporizer, this can hold a larger amount of liquid alcohol and can vaporize gaseous alcohol. In the gaseous alcohol source, the liquid alcohol can be an aqueous alcohol solution of 20 vol% or more, preferably 25 vol% or more, more preferably 50 vol% or more, even more preferably 70 vol% or more, even more preferably 90 vol% or more, and particularly preferably 99 vol% or more, or 100 vol% alcohol. The alcohol may evaporate naturally, or a mechanism for evaporation may be provided. Mechanisms for evaporating alcohol include heating mechanisms and ultrasonic mechanisms. Mechanisms for spraying alcohol include sprayers, including atomizers. When the alcohol is to be in the form of a mist or droplets, a sprayer or the like can be used. In the present invention, the "gasificant alcohol source" can be equipped with one or more of these mechanisms. The gaseous alcohol source may be housed in packaging that allows gaseous alcohol to pass through, and such packaging can be made of cloth, nonwoven fabric, paper, resin film, or the like.

[0048] 4. Antibacterial In this invention, "antibacterial" means at least inhibiting or preventing the growth of bacteria. Examples of "bacteria" include bacteria and fungi, such as E. coli, yeast, and mold, but are not limited to these. The antibacterial effect in this invention is the antibacterial effect brought about by the contact between platinum group element-supported porous silica and alcohol. The mechanism of action of this antibacterial effect is not clear, but it is thought that the platinum group elements in the platinum group element-supported porous silica act as a catalyst, oxidizing the gaseous alcohol to generate an antibacterial component, and that this antibacterial component inhibits or prevents the growth of bacteria.

[0049] In this invention, when ethanol is used as the alcohol, ethanol is oxidized to produce acetaldehyde, and carboxylic acid (acetic acid) and peracetic acid are generated via acetaldehyde. One or more of the group consisting of aldehydes, carboxylic acids, and peracetic acid act as antibacterial components, and peracetic acid in particular has a high antibacterial effect.

[0050] 5. Device The "device" in the present invention comprises a porous silica-containing portion supporting platinum group elements and a gaseous alcohol source, characterized in that the porous silica-containing portion supporting platinum group elements and the gaseous alcohol source are arranged adjacent to each other such that gaseous alcohol originating from the gaseous alcohol source permeates through the porous silica-containing portion supporting platinum group elements and comes into contact with the platinum group elements.

[0051] In the present invention, since the platinum group element-supported porous silica-containing portion and the gaseous alcohol source are arranged adjacent to each other as described above, the gaseous alcohol generated from the gaseous alcohol source efficiently permeates through the platinum group element-supported porous silica-containing portion, comes into contact with the platinum group elements in the platinum group element-supported porous silica, and is oxidized, thereby efficiently generating an antibacterial component, which can be released from the device.

[0052] In the present invention, the platinum group element-supported porous silica-containing portion and the gaseous alcohol source should be arranged adjacent to each other so that the gaseous alcohol from the gaseous alcohol source permeates through the platinum group element-supported porous silica-containing portion and comes into contact with the platinum group elements. There are no structural restrictions, and any arrangement or form is possible, but preferably, the platinum group element-supported porous silica-containing portion and the gaseous alcohol source have a laminated structure. Having a laminated structure between the platinum group element-supported porous silica-containing portion and the gaseous alcohol source is preferable because it increases the contact area between the gaseous alcohol source and the platinum group element-supported porous silica-containing portion, allowing the gaseous alcohol from the gaseous alcohol source to efficiently permeate through the platinum group element-supported porous silica-containing portion and come into contact with the platinum group elements.

[0053] In this invention, since gaseous alcohol and porous silica supporting platinum group elements can efficiently come into contact and react, it is not necessary to fill the entire space where the porous silica supporting platinum group elements and the alcohol coexist with alcohol, thereby reducing the amount of alcohol used. Furthermore, in the present invention, since gaseous alcohol and porous silica supported with platinum group elements can efficiently come into contact and react, the rate at which antibacterial components are generated within the device can be expressed by the following equation (2). The rate of antibacterial component generation = k [amount of platinum group elements] × [amount of alcohol] ... Equation (2) (k is the reaction constant) Therefore, by increasing the amount / concentration of alcohol in the device, it is possible to increase the rate of antibacterial component generation, thereby reducing the amount of expensive platinum group elements used in the device. In the present invention, the amount / concentration of alcohol in the device can be adjusted by the amount / concentration of alcohol contained in a gaseous alcohol source, and the amount of platinum group elements in the device can be adjusted by the amount of platinum group elements contained in the platinum group element-supported porous silica and / or the platinum group element-supported porous silica-containing portion.

[0054] In the present invention, the platinum group element-supported porous silica-containing portion and the gaseous alcohol source may be arranged directly adjacent to each other, or a filter permeable to the gaseous alcohol generated from the gaseous alcohol source may be placed between them. In particular, the filter is preferably one that permeates and slowly releases the gaseous alcohol generated from the gaseous alcohol source (hereinafter sometimes referred to as a "sustained-release filter"). The sustained-release filter only needs to have sustained permeability to gaseous alcohol, and its composition and structure are not particularly limited, but for example, a porous resin film made of one or more materials selected from the group consisting of polyethylene, polypropylene, polyurethane, ethylene vinyl alcohol, polytetrafluoroethylene, polyester, nylon, polystyrene, polylactic acid, silicon, cellulose, polyvinyl chloride, nonwoven fabric, etc. can be suitably used. In the present invention, if there is packaging material that contains the platinum group element-supported porous silica-containing portion and / or the gaseous alcohol source, the filter and the sustained-release filter may be at least a part of this packaging material.

[0055] In the present invention, the surface of the platinum group element-supported porous silica-containing portion opposite to the surface adjacent to the gaseous alcohol source may be provided with an air-permeable filter (hereinafter sometimes referred to as "air filter"). The air filter only needs to be permeable to air, and may have openings as needed. Its composition and structure are not particularly limited, but for example, metal, cloth, nonwoven fabric, paper, resin, etc., can be used. In the present invention, by providing an air filter, it is made easier for the generated antibacterial components to be released from the device and to take in oxygen and other elements involved in the generation reaction of the antibacterial components. In the present invention, if there is packaging material for containing the platinum group element-supported porous silica-containing portion, the air filter may be at least a part of that packaging material.

[0056] In the present invention, the gaseous alcohol source may be provided with a structure capable of blocking air permeation (hereinafter sometimes referred to as "air-blocking structure") on the side opposite to the side adjacent to the platinum group element-supported porous silica-containing portion. The air-blocking structure only needs to be impermeable to air, and its composition and structure are not particularly limited, but for example, metal, resin, silicon, etc. can be used. In the present invention, by providing an air-blocking structure, the gaseous alcohol generated from the gaseous alcohol source is prevented from escaping from the side opposite to the side adjacent to the platinum group element-supported porous silica-containing portion, facilitating its movement toward the platinum group element-supported porous silica-containing portion and promoting permeation through the platinum group element-supported porous silica-containing portion. In the present invention, if there is packaging material for containing the gaseous alcohol source, the air-blocking structure may be at least a part of that packaging material.

[0057] In this device, the platinum group element-supported porous silica-containing portion and the gaseous alcohol source can be positioned and held in place using any means (e.g., adhesive, packaging material, frame, case, etc.) as needed, together with a sustained-release filter, air filter, air barrier structure, etc., as long as the alcohol, antibacterial component, and air can behave as desired.

[0058] The following describes a device according to the present invention with reference to the drawings. However, the embodiments described below are merely examples (representative examples) of the present invention and are only illustrative for carrying out the present invention. The present invention is not limited to these embodiments unless it exceeds the gist of the invention.

[0059] Figure 1 shows a schematic cross-sectional view of a device 10 having a laminated structure in which a platinum group element-supported porous silica-containing portion 11 and a gaseous alcohol source 12 having the form of an alcohol vaporizer impregnated with liquid alcohol as a medium are located. The device further includes a sustained-release filter 13 between the platinum group element-supported porous silica-containing portion 11 and the gaseous alcohol source 12, an air filter 14 on the side of the platinum group element-supported porous silica-containing portion 11 opposite to the side adjacent to the gaseous alcohol source 12, and an air barrier structure 15 on the side of the gaseous alcohol source 12 opposite to the side adjacent to the platinum group element-supported porous silica-containing portion 11. In this device, the gaseous alcohol generated in the gaseous alcohol source 12 is prevented from escaping from this side by the air-blocking structure 15, and is efficiently released gradually through the sustained-release filter 13 to the platinum group element-supported porous silica-containing section 11. The antibacterial components generated in the platinum group element-supported porous silica-containing section 11 are released from the device through the air filter 14.

[0060] In this device, the platinum group element-supported porous silica-containing portion 11 has a sheet-like form, and its thickness can be 1 to 100 mm, preferably about 2 to 800 mm. Its size (i.e., the size of the surface perpendicular to the thickness direction) can be appropriately selected depending on how the device is used and is not particularly limited, but it can be in the range of 10 to 3,000 mm in length, preferably about 25 to 2,500 mm, and 10 to 13,000 mm in width, preferably about 25 to 12,000 mm. Its shape is not particularly limited and can take any shape such as a triangle, square, pentagon, hexagon, octagon, or other polygon, a circle, or an ellipse. In this device, the content of platinum group element-supported porous silica in the platinum group element-supported porous silica-containing portion 11 is not particularly limited, but is 5 to 150 g / m². 2 Preferably 10-100 g / m 2 It can be considered to be of a certain degree.

[0061] In this device, the platinum group element-supported porous silica-containing portion 11 can be a structure in which platinum group element-supported porous silica is fixed to a nonwoven fabric, which is particularly preferable.

[0062] In this device, the gaseous alcohol source 12 has a sheet-like form, and its thickness can be 1 to 200 mm, preferably about 2 to 150 mm. It is preferable that its size (i.e., the size of the surface perpendicular to the thickness direction) and shape be the same as the platinum group element-supported porous silica-containing portion 11 in order to efficiently guide the gaseous alcohol generated in the gaseous alcohol source 12 to the platinum group element-supported porous silica-containing portion 11.

[0063] In this device, the gaseous alcohol source 12 can be an alcohol vaporizer in which liquid alcohol is impregnated into a nonwoven fabric, which is particularly suitable.

[0064] In this device, the sustained-release filter 13 has a sheet-like form, and its thickness can be 0.001 to 1 mm, preferably about 0.005 to 0.7 mm, depending on the desired sustained release of the gaseous alcohol generated in the gaseous alcohol source 12. It is preferable that its size (i.e., the size of the surface perpendicular to the thickness direction) and shape be the same as the gaseous alcohol source 12 and the platinum group element-supported porous silica-containing portion 11 in order to efficiently and sustainably release the gaseous alcohol generated in the gaseous alcohol source 12 into the platinum group element-supported porous silica-containing portion 11.

[0065] In this device, a porous resin film can be particularly preferably used for the sustained-release filter 13.

[0066] In this device, the air filter 14 has a sheet-like form, and its thickness can be 0.001 to 30 mm, preferably about 0.005 to 20 mm. It is preferable that its size (i.e., the size of the surface perpendicular to the thickness direction) and shape be the same as the platinum group element-supported porous silica-containing portion 11, so as not to hinder the release of antibacterial components generated in the platinum group element-supported porous silica-containing portion 11 from the device, and to not obstruct the intake of air (containing oxygen and water) into the platinum group element-supported porous silica-containing portion 11.

[0067] In this device, the air filter 14 can be made of a sheet of nonwoven fabric, which is particularly suitable.

[0068] In this device, the air barrier structure 15 has a sheet-like form, and its thickness can be 0.001 to 1 mm, preferably about 0.005 to 0.7 mm. Its size (i.e., the size of the surface perpendicular to the thickness direction) and shape are preferably the same as the gaseous alcohol source 12 in order to efficiently prevent the gaseous alcohol generated in the gaseous alcohol source 12 from escaping from the surface opposite to the surface of the platinum group element-supported porous silica-containing portion 11.

[0069] In this device, the air barrier structure 15 can be made of a metal sheet, which is particularly suitable.

[0070] In this device, the sheets forming each layer may be bonded to each other to form a laminated structure, as long as the alcohol, antibacterial components, and air can behave as desired, or / or the sheets forming each layer may be housed and held in a packaging material, frame, case, etc., that can hold them in a predetermined order, thereby forming a laminated structure.

[0071] In this device, the outer surface of the air-blocking structure 15 (i.e., the surface opposite to the surface adjacent to the gaseous alcohol source 12 (or the outer surface of packaging materials, etc., if included in them)) may be provided with an adhesive layer as needed. By providing an adhesive layer, it is preferable that the device be attached to and held in place on the ceiling, wall, or floor surface of the space in which it is used.

[0072] Figure 2 shows a schematic cross-sectional view of a device 20 having a laminated structure consisting of a platinum group element-supported porous silica-containing portion 21 and a gaseous alcohol source 22 having the form of a container holding liquid alcohol 26. The device further includes a sustained-release filter 23 between the platinum group element-supported porous silica-containing portion 21 and the gaseous alcohol source 22, and an air filter 24 on the side of the platinum group element-supported porous silica-containing portion 21 opposite to the side adjacent to the gaseous alcohol source 22.

[0073] In this device, the platinum group element-supported porous silica-containing portion 21, the sustained-release filter 23, and the air filter 24 can have the same configuration as the platinum group element-supported porous silica-containing portion 11, the sustained-release filter 13, and the air filter 14 of the above-mentioned device 10.

[0074] In this device, the size (volume) of the gaseous alcohol source 22 can be appropriately selected depending on the manner in which the device is used and is not particularly limited. The opening of the container of the gaseous alcohol source 22 is sealed by a sustained-release filter 23, and the gaseous alcohol generated in the gaseous alcohol source 22 is efficiently and slowly released through the sustained-release filter 23 to the platinum group element-supported porous silica-containing section 21, and the antibacterial components generated in the platinum group element-supported porous silica-containing section 21 are released from the device through an air filter 24.

[0075] In this device, a container made of resin can be particularly preferred as the gaseous alcohol source 22.

[0076] In this device, the liquid alcohol 26 can be included in any amount as long as it can generate gaseous alcohol, and can be provided in an amount of 70% or more, preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more of the volume of the gaseous alcohol source 22.

[0077] In this device, the sheets forming each layer and the gaseous alcohol source may be bonded to each other to form a laminated structure, as long as the alcohol, antibacterial component, and air can behave as desired, or / or the sheets forming each layer and the gaseous alcohol source may be housed and held in a packaging material, frame, case, etc., that can hold them in a predetermined order, thereby forming a laminated structure.

[0078] 6. Antibacterial method The present invention also relates to an antimicrobial method using the above-mentioned device according to the present invention. In the method of the present invention, an antibacterial effect can be exerted by an antibacterial component released from the above-mentioned device, or, in the case of ethanol used as the alcohol, one or more antibacterial components selected from the group consisting of aldehydes, carboxylic acids, and peracetic acid. In the method of the present invention, liquid alcohol may be added to the gaseous alcohol source as needed.

[0079] 7. Food storage methods The present invention also relates to a method for preserving food using the above-mentioned device according to the present invention. In the method of the present invention, food is stored in a space in which an antibacterial effect is obtained by an antibacterial component released from the above-mentioned device, or, in the case of ethanol used as alcohol, one or more antibacterial components selected from the group consisting of aldehydes, carboxylic acids, and peracetic acid. As a result, bacterial growth can be suppressed or prevented in the stored food, and it can be preserved for a longer period of time compared to when the above-mentioned device is not present. In the method of the present invention, liquid alcohol may be added to the gaseous alcohol source as needed. [Explanation of symbols]

[0080] Devices 10, 20 Platinum group element-supported porous silica-containing parts 11, 21 Gaseous alcohol sources 12, 22 Slow-release filters 13, 23 Air filters 14, 24 Air-blocking structure 15 Liquid alcohol 26

Claims

1. A device comprising a porous silica-containing portion supporting platinum group elements and a gaseous alcohol source, wherein the porous silica-containing portion supporting platinum group elements and the gaseous alcohol source are arranged adjacent to each other such that gaseous alcohol originating from the gaseous alcohol source permeates the porous silica-containing portion supporting platinum group elements and comes into contact with the platinum group elements.

2. The device according to claim 1, further comprising a filter between the platinum group element-supported porous silica-containing portion and the gaseous alcohol source, through which gaseous alcohol permeates and is slowly released.

3. The device according to claim 1, wherein the platinum group element-supported porous silica-containing portion has a structure in which the platinum group element-supported porous silica is fixed to a porous member.

4. The device according to claim 1, wherein the gaseous alcohol source has a structure in which liquid alcohol is impregnated into a medium, or a structure in which liquid alcohol is contained in a container.

5. The device according to claim 1, wherein the porous silica-containing portion supporting the platinum group element has a filter on the side opposite to the side adjacent to the gaseous alcohol source that allows air to pass through.

6. The device according to claim 1, wherein the gaseous alcohol source has a structure on the side opposite to the side adjacent to the platinum group element-supported porous silica-containing portion that can block the permeation of air.

7. The device according to claim 1, wherein the platinum group element-supported porous silica-containing portion and the gaseous alcohol source have a laminated structure.

8. The device according to claim 1, wherein the platinum group element is platinum.

9. The device according to claim 1, wherein the alcohol is ethanol.

10. A method for antimicrobial action using the device described in claim 1.

11. The antibacterial method according to claim 10, wherein one or more antibacterial components selected from aldehyde, carboxylic acid, and peracetic acid are released from the device.

12. A method for preserving food using the device described in claim 1.

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