Space sterilization or inactivation method

Abstract

The present invention provides a method for degerming or inactivating bacteria or viruses floating in the air, the method comprising the steps of: preparing a humidifier filled with an aqueous solution having hypochlorous acid as the main component; and operating the humidifier to spray an aqueous solution having hypochlorous acid as the main component to the space, the spraying being performed while humidifying the space, and the chlorine in the aqueous solution being chlorine of hypochlorous acid at least 40 mol%.

Description

Technical Field

[0001] The present invention relates to a method for sterilizing or inactivating bacteria or viruses floating in space by using an aqueous solution with hypochlorous acid as a main component. Background Art

[0002] In recent years, the new coronavirus has been raging around the world, and my country is about to usher in the seventh wave of infection. As the infection route of the new coronavirus, the main method is aerosol infection.

[0003] As a result, methods and systems for sterilizing or inactivating various bacteria and viruses floating in the air have begun to emerge. On the other hand, due to insufficient evidence of their effectiveness, the Consumer Affairs Agency has repeatedly issued correction advice on the grounds of "misidentification of good quality" in the gift indication law.

[0004] And, most importantly, we need to find a method to sterilize or inactivate floating bacteria or viruses that is safe for the human body.

[0005] The present inventors believed that using an aqueous solution with hypochlorous acid as the main component that meets specific conditions is an effective means for sterilizing or inactivating planktonic bacteria or viruses that are safe for the human body, and conducted intensive research (see Patent Documents 1 and 2).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2021-171323

[0009] Patent Document 2: Japanese Patent Application Publication No. 2021-172649 Summary of the invention

[0010] Problems to be solved by the invention

[0011] Furthermore, when the aqueous solution is used to sterilize or inactivate bacteria or viruses floating in the air, a dedicated spray device or a dedicated special method is not required, and it is expected to be generally usable in general households or facilities.

[0012] On the other hand, commercially available humidifiers mainly include heating type (steam type), vaporization type, ultrasonic type, and a hybrid type that combines both heating type and ultrasonic type. In particular, when using an ultrasonic humidifier to humidify a space with tap water, there is the following problem: Legionella bacteria (hereinafter referred to as Legionella) proliferate in the tank or spray mechanism in the humidifier that has been used for a long time without internal cleaning, and it spreads into the space, thereby causing Legionnaires' disease. Legionnaires' disease is a respiratory tract infection caused by inhaling Legionella, which is widely inhabited in the environment, into the lungs along with aerosols as one of the main causes. Legionnaires' bacteria inhabit natural environments such as soil and rivers, but the number of Legionella bacteria in natural environments is small. It is believed that Legionnaires' disease is a problem mainly because of Legionella bacteria that are produced and proliferated in artificial water environments.

[0013] Therefore, an object of the present invention is to provide a method for sterilizing or inactivating bacteria or viruses floating in space which is more effective and safe for the human body and can be generally used in ordinary households or facilities.

[0014] Another object of the present invention is to provide a method for using a humidifier capable of suppressing the proliferation of Legionella in the humidifier.

[0015] Technical means of solving problems

[0016] The inventors have studied the above-mentioned problems and found that by using an aqueous solution containing hypochlorous acid as a main component that meets specific conditions and spraying it while humidifying it with a humidifier, it is possible to suppress the proliferation of Legionella in the humidifier while more efficiently sterilizing or inactivating bacteria or viruses floating in the air, thus completing the present invention. The method of the present invention is safe for the human body because it sprays an aqueous solution with a low chlorine concentration into the air.

[0017] That is, the present invention relates to the following scheme:

[0018] [1] A method characterized in that it is a method for sterilizing or inactivating bacteria or viruses floating in the air, comprising the following steps:

[0019] preparing a humidifier filled with an aqueous solution containing hypochlorous acid as a main component; and

[0020] The humidifier is operated to spray the aqueous solution into the space.

[0021] The spraying is carried out while humidifying the space.

[0022] 40 mol % or more, preferably 50 mol % or more, more preferably 60 mol % or more, further preferably 70 mol % or more, particularly preferably 80 mol % or more, most preferably 90 mol % or more of the chlorine in the aqueous solution is chlorine in the form of hypochlorous acid;

[0023] [2] The method according to [1] above, characterized in that the growth of Legionella bacteria in the humidifier is inhibited;

[0024] [3] The method according to [1] or [2] above, characterized in that the humidifier is an ultrasonic type;

[0025] [4] The method according to any one of [1] to [3] above, wherein the total amount of alkali metal ions and alkaline earth metal ions in the aqueous solution is less than 1.0 mEq / L, preferably less than 0.8 mEq / L, and more preferably less than 0.5 mEq / L.

[0026] [5] The method according to any one of [1] to [4] above, wherein the total concentration of chlorine in the aqueous solution is 1.0 to 20.0 ppm;

[0027] [6] The method according to [5] above, characterized in that the total concentration of chlorine in the aqueous solution is 1.0 to 5.0 ppm;

[0028] [7] The method according to [6] above, characterized in that the total concentration of chlorine in the aqueous solution is 3.0 to 5.0 ppm;

[0029] [8] The method according to any one of [1] to [7] above, characterized in that the spraying is performed while humidifying so that the relative humidity of the space is increased by 10 to 60% RH, preferably by 10 to 40% RH, and more preferably by 10 to 20% RHD;

[0030] [9] The method according to any one of [1] to [8] above, wherein the aqueous solution filled in the humidifier is replaced once a day; and

[0031]

[10] A method of use, characterized in that it is a method of use of a humidifier for inhibiting the growth of Legionella bacteria,

[0032] An aqueous solution containing hypochlorous acid as a main component is used for humidification, and 40 mol % or more of chlorine in the aqueous solution is chlorine of hypochlorous acid.

[0033] Effects of the Invention

[0034] According to the present invention, a commercially available humidifier can be used. By using an aqueous solution containing hypochlorous acid as the main component and in which 40 mol % or more of the chlorine in the aqueous solution is chlorine in the form of hypochlorous acid, a method for sterilizing or inactivating bacteria or viruses floating in the air that is more effective and safe for the human body and can also be used in general households or facilities can be provided.

[0035] Furthermore, according to the method for using the humidifier of the present invention, the proliferation of Legionella in the humidifier can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a diagram showing the results of a Legionella growth inhibition test in an ultrasonic tank of an ultrasonic humidifier.

[0037] Figure 2 This is a diagram for explaining the arrangement of equipment in a test space of a space sterilization test.

[0038] Figure 3 This is a graph showing the sterilization rate (%) of Staphylococcus aureus based on the space sterilization test.

[0039] Figure 4 This is a graph showing the inactivation rate (%) of Escherichia coli phage MS2 based on the spatial inactivation test.

[0040] Figure 5 This is a graph showing the inactivation rate (%) of Escherichia coli phage MS2 based on the spatial inactivation test.

[0041] Figure 6 This is a graph showing the inactivation rate (%) of Escherichia coli phage MS2 based on the spatial inactivation test.

[0042] Figure 7 This is a graph showing the inactivation rate (%) of Escherichia coli phage MS2 based on the spatial inactivation test.

[0043] Figure 8 This is a graph showing the inactivation rate (%) of Escherichia coli phage MS2 based on the spatial inactivation test.

[0044] Fig. 9 This is a graph showing the inactivation rate (%) of Escherichia coli phage MS2 based on the spatial inactivation test. DETAILED DESCRIPTION

[0045] One embodiment of the present invention is a method as described above, characterized in that it is a method for sterilizing or inactivating bacteria or viruses floating in a space (hereinafter, also referred to as space sterilization), comprising the following steps: preparing a humidifier filled with an aqueous solution containing hypochlorous acid as a main component; and operating the humidifier to spray the aqueous solution containing hypochlorous acid as a main component to the space, the spraying being carried out while humidifying the space, and 40 mol% or more of the chlorine in the aqueous solution being chlorine of hypochlorous acid. In fact, the effect of sterilizing or inactivating bacteria or viruses floating in the space when humidifying by operating the humidifier using simple water (purified water) was verified, but the effect could not be confirmed. On the other hand, according to the method of the present invention, it was also confirmed that by humidifying with an aqueous solution containing hypochlorous acid as a main component, in which 40 mol% or more of the chlorine in the aqueous solution is chlorine of hypochlorous acid, bacteria or viruses floating in the space can be sterilized or inactivated more efficiently.

[0046] The bacteria to be sterilized in the space are not particularly limited as long as they can float in the space, and examples thereof include:

[0047] ・ Gram-negative facultative anaerobic rods such as Escherichia, Shigella, Salmonella, Klebsiella, Proteus, Yersinia, Vibrio, Pasteurella, Campylobacter, Helicobacter, Yersinia, Serratia, Borrelia, Treponema, Flavobacterium, Capnocytophaga, and Haemophilus

[0048] ・Gram-negative aerobic rods such as Pseudomonas, Bordetella, Brucella, Bartonella, Aeromonas, Burkholderia, Acinetobacter, Stenotrophomonas, and Francisella

[0049] · Gram-negative obligate anaerobic rods such as Bacteroides and Porphyromonas

[0050] · Gram-negative cocci such as Moraxella and Neisseria

[0051] · Gram-positive cocci such as Staphylococcus, Streptococcus, Enterococcus, Mycobacterium, and Micrococcus

[0052] ・Gram-positive rod bacteria such as Clostridioides, Bacillus, Corynebacterium, Listeria, Nocardia, Propionibacterium, Bifidobacterium, Lactobacillus, Actinomyces, and Eubacterium

[0053] ・Atypical bacteria such as Mycoplasma, Legionella, Clamydia, Chlamydophila, Rickettsia, Ehrlichia, Anaplasma, Neorickettsia, and Coxiella

[0054] Fungi belonging to the genera Candida, Aspergillus, Cryptococcus, Pneumocystis, Trichophyton, Microsporum, and Epidermophyton, etc.

[0055] There is no special limitation on the viruses that can be sterilized in the space as long as they can float in the space. For example, they include: molluscum contagiosum virus, herpes simplex virus, varicella-zoster virus, rotavirus, human papillomavirus, poliovirus, coxsackievirus, rhinovirus, rubella virus, measles virus, influenza virus, mumps virus, RS virus, hepatitis virus, human immunodeficiency virus (HIV), coronavirus and new coronavirus, etc.

[0056] (Aqueous solution with hypochlorous acid as the main component)

[0057] According to one embodiment of the present invention, the aqueous solution with hypochlorous acid as the main component is not particularly limited as long as the total chlorine in the aqueous solution is 40 mol% or more of the chlorine in the aqueous solution as hypochlorous acid. The aqueous solution that can be filled in the humidifier described later is preferably an aqueous solution with hypochlorous acid as the main component (methods 1 and 2) according to patent document 1 or 2 (Japanese Patent Publication No. 2021-171323, Japanese Patent Publication No. 2021-172649). Hereinafter, the first and second methods of the aqueous solution with hypochlorous acid as the main component are described. In particular, the description without clear description of the method applies to all aqueous solutions with hypochlorous acid as the main component used in any embodiment of the present invention.

[0058] In this specification, "ppm" (mg / kg) used as a unit of concentration can be replaced with mg / L unless otherwise specified.

[0059] In this specification, "having hypochlorous acid as the main component" means that hypochlorous acid is contained as a representative component other than water as a solvent, and does not mean that hypochlorous acid accounts for most of the constituent components or that hypochlorous acid is the largest component among the components other than water. Therefore, as long as it does not adversely affect the disinfection and sterilization function and storage stability, other components, especially chlorine-containing components or components for adjusting pH, such as HCl, may be contained as the main components in addition to water and hypochlorous acid. In contrast, in conventional hypochlorous acid water, the content of undecomposed sodium chloride and hydrogen chloride, a component that contributes to pH, is high, and the proportion of hypochlorous acid is low.

[0060] The aqueous solution with hypochlorous acid as the main component used in the present invention is characterized in that more than 40 mol% of the sum of the chlorine in the aqueous solution is the chlorine of hypochlorous acid. For this, when the sum of the mol equivalents of the components containing chlorine atoms in the aqueous solution is set to 100 mol%, the amount of hypochlorous acid in the aqueous solution is represented by the ratio of the molar amount of chlorine from hypochlorous acid. Thus, it is believed that even if HCl is included in the aqueous solution, the amount of HCl will not exceed 60 mol% of the sum of the chlorine in the aqueous solution. The pH of the aqueous solution can be made as close to neutral as possible, and an aqueous solution with hypochlorous acid as the main component having excellent storage stability can be obtained. In addition, such an aqueous solution is also less concerned about metal corrosion and resin degradation.

[0061] For an aqueous solution with hypochlorous acid as the main component, more than 40 mol% of the total chlorine in the aqueous solution is chlorine from hypochlorous acid, i.e., chlorine from hypochlorous acid, and preferably more than 50 mol%, more preferably more than 60 mol%, further preferably more than 70 mol%, particularly preferably more than 80 mol%, and most preferably more than 90 mol% of the total chlorine in the aqueous solution is chlorine from hypochlorous acid. If the total amount of chlorine in the aqueous solution is large, chlorine gas is easily generated. For example, in the case where the aqueous solution is electrolyzed water, if the ratio of chlorine from hypochlorous acid to the total chlorine in the aqueous solution is less than 40 mol%, the ratio of hydrogen chloride increases, and the hazards such as irritation or corrosion caused by hydrogen chloride tend to become greater. Corrosion of metals refers to the combination of metal ions with chlorine or alkali (hydroxyl, nitrate, sulfate, etc.), oxygen, etc., and the charge in the metal is taken away, ionized and detached.

[0062] The aqueous solution with hypochlorous acid as the main component is preferably an aqueous solution in which the total concentration of chlorine in the aqueous solution is 1.0 to 20.0 ppm. It is more preferably 1.0 to 5.0 ppm, and even more preferably 3.0 to 5.0 ppm. The concentration can be adjusted by dilution with purified water or the like. Even with this extremely low chlorine concentration, a sufficient space sterilization effect can be obtained, and it is believed that there is almost no effect on the human body moving in the sprayed space (the WHO Drinking Water Quality Guidelines believe that the chlorine concentration that has no effect on human health is 5 mg / L or less, that is, 5 ppm or less). It should be noted that when the aqueous solution with hypochlorous acid as the main component used in the present invention is sprayed into the space, the chlorine concentration in the space is in the range of about 0.005 to 0.01 ppm.

[0063] The water used in preparing the aqueous solution containing hypochlorous acid as the main component is preferably pure water, purified water, ion-exchanged water, or the like in order to suppress the incorporation of unexpected components such as metal ions and organic substances contained in tap water.

[0064] In the aqueous solution of the first mode of the aqueous solution with hypochlorous acid as the main component, it is preferred that alkali metal ions or alkaline earth metal ions are not contained as much as possible. Specifically, the sum of alkali metal ions and alkaline earth metal ions is preferably less than 1.0mEq / L, more preferably less than 0.8mEq / L, and further preferably less than 0.5mEq / L. By making the sum of alkali metal ions or alkaline earth metal ions less than 1.0mEq / L, there is a tendency to suppress the generation of chlorine and increase the stability. In other words, by not containing alkali metal ions and alkaline earth metal ions that are counter ions of chlorine as much as possible, the generation of hydrogen chloride gas and the decomposition (inactivation) of hypochlorous acid can be suppressed. When such an aqueous solution is sprayed indoors, due to the low concentration of hydrogen chloride and salt concentration, corrosion, especially the influence on electronic substrates, can be suppressed to a lower level.

[0065] The alkali metal ions or alkaline earth metal ions contained for adjusting pH when necessary are not particularly limited and can be added in the form of salts. Examples of such alkali metal ion salts include sodium (Na) or potassium (K) salts, and examples of such alkaline earth metal ion salts include magnesium (Mg) or calcium (Ca) salts. On the other hand, salts of rubidium (Rb) and osmium (Os) are indicated to be carcinogenic, and therefore, are preferably not used.

[0066] In the first embodiment of the aqueous solution containing hypochlorous acid as a main component, the concentration of anions in the aqueous solution other than hypochlorous acid is preferably less than 1.0 mmol / L, more preferably 0.9 mmol / L or less, and even more preferably 0.4 mmol / L or less.

[0067] The aqueous solution of the first embodiment of the aqueous solution containing hypochlorous acid as a main component is preferably electrolyzed water, and specifically, preferably electrolyzed water containing hypochlorous acid as a main component obtained by electrolyzing hydrochloric acid or sodium chloride as a raw material.

[0068] The pH of the aqueous solution of the first mode of the aqueous solution with hypochlorous acid as the main component is preferably 2.7 or more, more preferably 3.2 or more, further preferably 3.5 or more, and particularly preferably 5.8 or more. By making the pH of the aqueous solution with hypochlorous acid as the main component to be 2.7 or more, there is a tendency to reduce corrosiveness and be able to be used for various purposes. In particular, when using an aqueous solution with hypochlorous acid as the main component in a humidifier, an air purifier, etc., due to concerns about corrosion and deterioration of the parts used in the device, the pH is preferably 3.2 or more. By making the pH to be 3.2 or more, the generation of chlorine (hydrogen chloride gas) can be further suppressed. In addition, it is preferred that the pH of the aqueous solution with hypochlorous acid as the main component is 5.8 or more and 6.5 or less, thereby, while the stimulation to the mucous membranes, etc. is reduced, it meets the drinking water standard.

[0069] The first mode of the aqueous solution with hypochlorous acid as the main component can be used for various purposes due to its characteristics such as not too low pH and strong bactericidal and antiviral ability. For example, it can be widely used in various fields such as public hygiene, food, and medical treatment, such as disinfection and sterilization in life. It can be appropriately used for disinfection, sterilization / sterilization of various items and environments such as clothes, tableware, glass containers, and plastic containers at home and medical sites. In particular, by adjusting the pH, it can also be appropriately used for skin washing and sterilization such as finger washing (hand washing and sterilization), and sterilization of space. When tap water is used in a humidifier or air purifier, fungi such as mold are sometimes generated in the water tank and the generated fungi are spread. On the other hand, if it is the above-mentioned aqueous solution with hypochlorous acid as the main component, since it contains hypochlorous acid with high bactericidal effect, it can maintain the sanitation not only in the device but also in the space. Therefore, it is preferably used instead of tap water in a humidifier or air purifier. In particular, in a mode that does not contain salt and has a pH that is not too low, it is considered to be more preferable to use it in a humidifier or an air purifier from the viewpoint of less concern about corrosion.

[0070] The first mode of aqueous solution containing hypochlorous acid as the main component can be prepared by various methods. For example, first, in a two-diaphragm three-chamber electrolytic cell in which the anode chamber, the cathode chamber, and the intermediate chamber containing the electrolyte disposed between the anode chamber and the cathode chamber are separated by diaphragms, an aqueous sodium chloride solution is used as the electrolyte for electrolysis, and acidic hypochlorous acid water is obtained on the anode side. At this time, usually, chlorine migrates in the anode and sodium migrates in the cathode, and the migrated chlorine reacts with water to generate hydrogen chloride (HCl) and hypochlorous acid (HClO), and oxygen is generated. On the cathode side, sodium reacts with water to generate sodium hydroxide, and hydrogen is generated. The reaction of sodium chloride and water is shown in the following formula. Stoichiometrically, the generation ratio of hypochlorous acid to hydrogen chloride will not be greater than 1:1, so the generation ratio of hypochlorous acid will not exceed that of hydrogen chloride.

[0071] 2NaCl+3H2O→2NaOH+HCl+HClO+H2

[0072] Next, the obtained acidic hypochlorous acid water is electrolyzed again to convert hydrogen chloride into hypochlorous acid, which can increase the ratio of hypochlorous acid to hydrochloric acid. By increasing the ratio of hypochlorous acid to hydrochloric acid, the pH can be tilted toward the neutral side at the same time. In order to obtain the desired ratio of hypochlorous acid to hydrochloric acid and the desired pH, the treatment (electrolysis of hypochlorous acid water) can be repeated as many times as necessary.

[0073] The second embodiment of the aqueous solution with hypochlorous acid as the main component is obtained by adding an alkaline substance to the aqueous solution of the first embodiment so that the pH is 5.0 to 7.0. Since the acid dissociation constant of hypochlorous acid is 7.5, by making the pH below 7.0, the proportion of non-dissociated hypochlorous acid in the aqueous solution exceeds 50% (by making the pH below 6.5, the proportion of non-dissociated hypochlorous acid in the aqueous solution becomes 90% or more), and higher bactericidal performance can be achieved. In addition, by making the pH above 5.8, it meets the standards for drinking water. In the second embodiment of the aqueous solution with hypochlorous acid as the main component, it is more preferable to make the pH 5.8 to 6.5. Here, as the alkaline substance, various pH adjusters can be used, specifically, for example, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, magnesium bicarbonate, sodium acetate, potassium acetate, calcium acetate, magnesium acetate, sodium citrate, potassium citrate, calcium citrate or magnesium citrate, their aqueous solutions, etc., among which sodium hydroxide or its aqueous solution is particularly preferably used.

[0074] The second mode of aqueous solution with hypochlorous acid as the main component has a pH of 5.0 to 7.0, which is neutral to weakly acidic, and thus becomes a pH close to the skin, so that the stimulation caused by acid or the itching caused by alkali is sharply reduced. In addition, by not leaning toward the alkaline side, the generation of trihalomethanes can also be suppressed. When the aqueous solution of the second mode is sprayed indoors, the corrosion, especially the influence on electronic substrates, can be suppressed to a low level due to the low concentration of hydrogen chloride and salt concentration. In addition to the uses of the aqueous solution of the first mode, it can also be further used for various purposes, for example, it can also be appropriately used for skin cleaning and disinfection such as finger washing (hand washing disinfection), sterilization of space, sterilization of instruments such as medical equipment, and sterilization of bedsores.

[0075] (humidifier)

[0076] The method of the present invention includes a system for spraying the above-mentioned aqueous solution with hypochlorous acid as the main component into the space using a humidifier. The spraying system is not particularly limited as long as it is a system that atomizes the aqueous solution with hypochlorous acid as the main component and sprays it into the space on the basis of atomization. In addition, according to the present invention, by humidifying the space at the same time, the sterilization or inactivation of bacteria or viruses floating in the space can be achieved very effectively. The humidifier used in the present invention can be a commercially available humidifier, or any of the heating type, vaporization type (steam type), ultrasonic type and a hybrid type that combines both heating type and ultrasonic type can be used, but from the perspective of being able to stably spray an aqueous solution with hypochlorous acid as the main component, an ultrasonic type is preferred. The ultrasonic humidifier used in the present invention, for example, includes シーエルミストL (manufactured by NIPRO Co., Ltd.), ウルリ / ウルーレ series (manufactured by NITORI Co., Ltd.) and HM-201 (manufactured by Starlight Technology Co., Ltd.).

[0077] However, especially when using tap water for ultrasonic humidifiers, the growth of Legionella becomes a problem and hygiene must be maintained on a daily basis. However, by using the above-mentioned aqueous solution with hypochlorous acid as the main component, the growth of Legionella in the humidifier can be suppressed. If it is implemented more hygienically, it is more preferred to replace the aqueous solution with hypochlorous acid as the main component, in which 40 mol% or more of the chlorine in the aqueous solution is chlorine from hypochlorous acid, once a day. Thus, another embodiment of the present invention is a method for using a humidifier that suppresses the growth of Legionella bacteria, characterized in that an aqueous solution with hypochlorous acid as the main component, in which 40 mol% or more of the chlorine in the aqueous solution is chlorine from hypochlorous acid, is used for humidification. In addition, those skilled in the art can understand that the description of the sterilization or inactivation method of the space of the present invention can also be applied to the method for using a humidifier that suppresses the growth of Legionella in a humidifier as long as there is no contradiction.

[0078] In the present invention, while humidifying the space, the above-mentioned aqueous solution is sprayed with 40 mol% or more of the chlorine in the aqueous solution as chlorine of hypochlorous acid, and the aqueous solution with hypochlorous acid as the main component. In one embodiment, it is ideal that, for the degree of humidification, it is preferably sprayed while humidifying, so that the relative humidity of the space increases by 10 to 60% RH, more preferably by 10 to 40% RH, and further preferably by 10 to 20% RH. Surprisingly, according to the present invention, it is known that by simultaneously spraying the aqueous solution with 40 mol% or more of the chlorine in the aqueous solution as chlorine of hypochlorous acid and the humidification of the same space, the bacteria or viruses floating in the space can be sterilized or inactivated in a synergistic manner. Generally speaking, the humidifier has a multi-stage spray speed setting function, so using this setting, humidification is performed with the hygrometer set in the space where the sterilization effect is expected as a mark to achieve the target humidity. Humidification is performed, and the time to reach the target relative humidity is preferably to obtain the sterilization effect early, so it is not particularly limited, preferably within 60 minutes, and more preferably within 30 minutes. Furthermore, it is more preferred that the aqueous solution containing hypochlorous acid as a main component, in which 40 mol % or more of the chlorine in the aqueous solution filling the humidifier is chlorine of hypochlorous acid, is replaced once a day because the sterilization or inactivation of the space can be performed more effectively.

[0079] Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not intended to be limited to these Examples.

[0080] Example

[0081] Production Example 1: Preparation of an aqueous solution containing hypochlorous acid as a main component (concentration: 10.0 ppm)

[0082] Using sodium chloride aqueous solution as the electrolyte, electrolysis was performed in a two-diaphragm three-chamber electrolytic cell to obtain strongly acidic hypochlorous acid water from the anode side. The obtained strongly acidic hypochlorous acid water was electrolyzed again to convert hydrogen chloride into hypochlorous acid, and an aqueous solution with hypochlorous acid as the main component was obtained with an increased ratio of hypochlorous acid to hydrochloric acid. Sodium hydroxide was added to the obtained 1L aqueous solution with hypochlorous acid as the main component to adjust the pH to 6.5. The pH was measured using a multifunctional water quality meter (MM-60, manufactured by DKK Toa Co., Ltd.). Furthermore, after adjusting the pH, chlorides other than hypochlorous acid were reduced by filtering using a filter membrane. Moreover, the total concentration of chlorine was adjusted to 10.0 ppm by diluting with purified water. At this time, by confirming that the pH was in the range of 5.0 to 7.0, it was ensured that more than 40 mol% of the chlorine in the aqueous solution was chlorine of hypochlorous acid. In addition, the total of alkali metal ions and alkaline earth metal ions in the aqueous solution was 0.8 mEq / L.

[0083] Preparation Example 2: Preparation of an aqueous solution containing hypochlorous acid as the main component (1.0 ppm)

[0084] The same procedures as in Production Example 1 were carried out except that the total chlorine concentration was adjusted to 1.0 ppm.

[0085] Preparation Example 3: Preparation of an aqueous solution containing hypochlorous acid as the main component (0.1 ppm)

[0086] The same procedures as in Production Example 1 were carried out except that the total chlorine concentration was adjusted to 0.1 ppm.

[0087] Preparation Example 4: Preparation of an aqueous solution containing hypochlorous acid as the main component (3.0 ppm)

[0088] The same procedures as in Production Example 1 were carried out except that the total chlorine concentration was adjusted to 3.0 ppm.

[0089] Reference Example 1

[0090] The sterilization effect of Legionella bacteria was confirmed by the following method. Legionella (Legionella pneumophila, obtained from ATCC) was cultured at 36±2°C for 18 to 24 hours using BCYEα medium (manufactured by Nissui Pharmaceutical Co., Ltd.), and then cultured again at 36±2°C for 18 to 24 hours after subculturing once. The bacteria were collected from the colonies obtained by culture and suspended in physiological saline to prepare a bacterial suspension (suspension concentration: about 108 CFU / mL). After mixing the suspension with the aqueous solution of Preparation Example 1 for 5 minutes (volume ratio 1:98), a reaction stop solution (0.5% sodium thiosulfate phosphate buffer) was added (hereinafter referred to as the "treatment group"). In addition, as a control, a liquid obtained by mixing the suspension with injection water for 5 minutes (volume ratio 1:98) was used (hereinafter referred to as the "control group"). For the treatment group and the control group, BCYEα medium was used to culture at 36±2°C for 1 day. The number of colonies obtained by the culture was measured using a colony counter to evaluate the bacterial count, and the sterilization effect was evaluated by calculating how much the bacterial count decreased compared with the bacterial count of the control group.

[0091] Reference Example 2

[0092] The same procedures as in Reference Example 1 were carried out except that the aqueous solution of Preparation Example 2 was used instead of the aqueous solution of Preparation Example 1.

[0093] Reference Example 3

[0094] The same procedures as in Reference Example 1 were carried out except that the aqueous solution of Production Example 3 was used as the aqueous solution of Production Example 1.

[0095] Comparative Reference Example 1

[0096] The same procedure as in Reference Example 1 was carried out except that tap water was used instead of the aqueous solution in Preparation Example 1. The chlorine concentration of the tap water was confirmed to be 0.16 ppm.

[0097] The results of Reference Examples 1 to 3 and Comparative Reference Example 1 are shown in Table 1. In Reference Examples 1 to 3 using the aqueous solutions of Preparation Examples 1 to 3, a high sterilization effect of 89% or more was shown, and further, in Reference Examples 1 and 2 using Preparation Examples 1 and 2 having high hypochlorous acid concentrations, a sterilization effect of 99.9% or more was shown.

[0098] [Table 1]

[0099] Table 1

[0100]

[0101] Example 1

[0102] The Legionella proliferation inhibition test in an ultrasonic humidifier was carried out by the following method. An ultrasonic humidifier (manufactured by NITORI Co., Ltd.: ウルリS (registered trademark)) in which the tank and the main ultrasonic tank were cleaned and sterilized in advance was prepared. 1.5L of the aqueous solution of Manufacturing Example 4 was filled in the tank of the humidifier. Then, a humidifier filled with the aqueous solution of Manufacturing Example 4 was set in a safety cabinet and operated for one hour a day to spray the aqueous solution of Manufacturing Example 4. It should be noted that the setting of the humidifier was implemented at "medium" (about 110mL / h±20%; catalog value).

[0103] The aqueous solution in the ultrasonic tank of the humidifier after spraying was sampled, and the sampled solution was cultured for 3 days using BCYEα medium at 36±2° C. The state of bacterial colony generation after culture was photographed and confirmed.

[0104] The above operation was performed for a maximum of 7 days. It should be noted that if the generation of bacterial colonies could be clearly confirmed, the test was terminated on the same day. In addition, the aqueous solution in the humidifier tank was not replaced after the spraying was completed on each day.

[0105] Example 2

[0106] The same procedure as in Example 1 was carried out except that the aqueous solution in the humidifier tank was replaced after the spraying was completed on each day.

[0107] Comparative Example 1

[0108] The same procedures as in Example 1 were carried out except that tap water was used instead of the aqueous solution in Preparation Example 4.

[0109] Comparative Example 2

[0110] The same procedures as in Example 2 were carried out except that tap water was used instead of the aqueous solution in Preparation Example 4.

[0111] The results of Examples 1, 2, and Comparative Examples 1 and 2 are shown in Figure 1 It can be seen that the aqueous solution of the present invention can delay the time of bacterial production in the humidifier compared with tap water, and by replacing the water every day, the production of bacteria during the test period can be completely suppressed.

[0112] Example 3

[0113] The space sterilization test for Staphylococcus aureus was carried out by the following method. The configuration of the equipment in the experiment is shown in FIG. Figure 2 .

[0114] In the test space 1 of 25.7m3 (W: 2.7m×D: 3.8m×H: 2.4m), Figure 2 An ultrasonic humidifier (Nipro Co., Ltd.: Sealer Mist L (registered trademark)) 3 is set at the position shown. The humidifier 3 is pre-filled with 3 L of the aqueous solution containing hypochlorous acid as the main component prepared in Manufacturing Example 4. The relative humidity in the space before the operation of the humidifier 3 is 50% RH. It should be noted that Figure 2 A circulator 4 is installed in advance at the position shown and is operated at a wind speed of 2 m / s so that the aqueous solution containing hypochlorous acid as a main component and Staphylococcus aureus to be sprayed, which will be described later, are fully distributed in the test space 1 .

[0115] A separately prepared suspension of Staphylococcus aureus (about 109 CFU / mL) is sprayed from the front chamber 2 from the spray port 7 using a sprayer (BGI: Collison Nebulizer CN-31I) 5. Staphylococcus aureus (purchased from the (independent) Product Evaluation Technology Foundation) was cultured at 36±2°C for 1 to 2 days using TSA medium (Difco), and then cultured again at 36±2°C for 1 day after subculture. The suspension is prepared by catching the colonies obtained by culture and suspending them in physiological saline. It should be noted that the suspension concentration is a value calculated by sampling the obtained suspension and calculating the number of colonies after culturing again for 1 day using TSA medium (Difco).

[0116] For the purpose of homogenizing the indoor air of the test space 1, after standing for 2 minutes from the spraying of Staphylococcus aureus, an aqueous solution containing hypochlorous acid as a main component was sprayed into the test space 1 at a spray rate of 400 mL / h for 30 minutes using the humidifier 3. At this time, the humidifier 3 was set to the turbo mode so that the relative humidity in the test space 1 was 90% RH within 30 minutes.

[0117] The time when the Staphylococcus aureus was sprayed and left to stand for 2 minutes was set as the start time 0 minute, and the sterilization rate (%) was measured 30, 60, and 120 minutes after that. The sterilization rate (%) was calculated as follows: Figure 2 The air sampler 8 shown collects the air sample of the test space 1 from the sample collection port 9, and after the prescribed treatment, the number of colonies obtained by the culture is measured using a colony counter, and the number is calculated by setting the number of bacteria at the start time 0 minutes to 100%. For the prescribed treatment, specifically, 20L of the air sample in the test space 1 is flowed from the outside of the test space 1 (front room 2) from the sample collection port 9 through a tube directly connected to the air sampler 8 into 20mL of physiological saline containing 0.015% of sodium thiosulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Based on the obtained liquid, a 10-fold dilution series is made using physiological saline, and after culturing for 1 day using SCD culture medium at 36±2°C, the number of colonies obtained is measured using a colony counter.

[0118] In addition, the chlorine concentration of the test space 1 after 30 minutes from the start was in the range of 0.005 to 0.01 ppm. This is also the same as in Examples 4 to 16 described later.

[0119] Comparative Example 3

[0120] The same procedures as in Example 3 were followed except that purified water was used instead of the aqueous solution containing hypochlorous acid as a main component prepared in Preparation Example 4.

[0121] Comparative Example 4

[0122] The same procedures as in Example 3 were performed except that humidification by the humidifier was not performed at all. That is, the relative humidity in the space was 50%.

[0123] The results of Example 3, Comparative Examples 3 and 4 are shown in Figure 3 In Example 3, a sterilization rate of 99.9% was achieved 30 minutes after the start time. In contrast, in Comparative Example 4, a sterilization rate of 90% was achieved in 120 minutes. In Comparative Example 3, no significant reduction in the number of bacteria was observed.

[0124] Example 4

[0125] A spatial inactivation test of Escherichia coli phage MS2 was conducted. The spraying operation of the virus suspension, the spraying operation of the test specimen, and the recovery operation of the air specimen were carried out according to Example 3, except that Escherichia coli phage MS2 was used instead of Staphylococcus aureus. It should be noted that the object is Escherichia coli phage MS2, so the preparation operation of the virus suspension and the culturing operation of the recovered liquid from the air specimen were switched to a method suitable for the virus. In addition, the sterilization rate (%) can be replaced by the inactivation rate (%).

[0126] The preparation of the virus suspension was specifically carried out as follows. Escherichia coli (purchased from the (unique) product evaluation technology foundation) was purchased, and after purchase, it was cultured at 36±2°C for 1 to 2 days using NB medium (manufactured by Difco), and then cultured at 36±2°C for 1 day after subculturing once, and the obtained colonies were collected and suspended in physiological saline. Escherichia coli phage MS2 (purchased from the (unique) product evaluation technology foundation) was inoculated therein, and after mixing with semi-fluid agar (NB medium (manufactured by Difco) + 0.5% sodium chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) + 0.5% agar (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)), it was layered on a normal agar medium (manufactured by Nissui Pharmaceutical Co., Ltd.). After culturing for 18 hours at 36±2°C, the E. coli was removed by centrifugation and filtered using a membrane filter with a pore size of 0.22 μm (manufactured by TPP Co.), and the resulting liquid was used as a virus suspension mother solution. The mother solution was diluted 100 times with sterile ion exchange water to obtain a virus suspension solution (109 PFU / mL) for testing. The suspension concentration is the value calculated by sampling the obtained suspension and inoculating E. coli again from the number of plaques after cultivation.

[0127] The culture operation of the recovered liquid from which the air specimen was recovered was specifically carried out as follows. Based on the obtained liquid, a 10-fold dilution series was prepared using PBS (manufactured by Elmex) and each was inoculated into the Escherichia coli suspension. The inoculated liquid was mixed with semi-fluid agar (NB medium (manufactured by Difco) + 0.5% sodium chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) + 0.5% agar (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)) and then overlapped on a normal agar medium (manufactured by Nissui Pharmaceutical Co., Ltd.), and after culturing at 36±2°C for 20 hours, the number of plaques obtained was measured.

[0128] Comparative Example 5

[0129] The same procedures as in Example 4 were performed except that purified water was used instead of the aqueous solution containing hypochlorous acid as a main component prepared in Preparation Example 4.

[0130] Comparative Example 6

[0131] The same procedures as in Example 4 were performed except that humidification by the humidifier was not performed at all. That is, the relative humidity in the space was 50%.

[0132] The results of Example 4, Comparative Examples 5 and 6 are shown in Figure 4 Example 4 showed an inactivation rate of 99% 30 minutes from the start time. In contrast, Comparative Example 6 did not reach an inactivation rate of 90% even after 120 minutes. In Comparative Example 5, no significant reduction in the number of viruses was confirmed.

[0133] Example 5

[0134] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 30%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 40% RH.

[0135] Example 6

[0136] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 30%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 50% RH.

[0137] Example 7

[0138] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 30%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 60% RH.

[0139] Example 8

[0140] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 40%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 50% RH.

[0141] Example 9

[0142] The procedure of Example 4 was carried out except that the relative humidity in the space before the operation of the humidifier was 40%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 60% RH.

[0143] Example 10

[0144] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 50%, the humidifier was set for 30 minutes, and the relative humidity in the space was 60% RH.

[0145] Embodiment 11

[0146] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 50%, the humidifier was set to 30 minutes, and the relative humidity in the space was 70% RH.

[0147] Example 12

[0148] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 50%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 80% RH.

[0149] Example 13 (Example 4)

[0150] The conditions are the same as those of Example 4, but for ease of understanding, this is Example 13.

[0151] Embodiment 14

[0152] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 60%, the humidifier was set for 30 minutes, and the relative humidity in the space was 70% RH.

[0153] Embodiment 15

[0154] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 60%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 80% RH.

[0155] Example 16

[0156] The procedure of Example 4 was followed except that the relative humidity in the space before the operation of the humidifier was 70%, the setting of the humidifier was 30 minutes, and the relative humidity in the space was 80% RH.

[0157] The results of Examples 5 to 7 are shown in Figure 5 The results of Examples 8 and 9 are shown in Figure 6 The results of Examples 10 to 13 are shown in Figure 7 The results of Examples 14 and 15 are shown in Figure 8 The results of Example 16 are shown in Fig. 9 It should be noted that Figures 5 to 9The results of Comparative Examples 5 and 6 are also shown in FIG. Although the lower the relative humidity of the space, the more difficult it is to inactivate, even in Example 5 (relative humidity change: 30% → 40%), which is considered to be the worst condition, it is possible to achieve more than 90% between 60 and 120 minutes from the start time, which is a good result compared to Comparative Example 6 (no humidification, relative humidity: maintained at 50%). Therefore, it is shown that if the aqueous solution containing hypochlorous acid as the main component of the present invention is sprayed while humidifying in a manner that increases the relative humidity of the space, a sterilization or inactivation effect is synergistically achieved. Therefore, according to the present invention, a sufficient sterilization or inactivation effect can be expected, especially even in the low-humidity winter period in Japan.

[0158] It should be noted that in the examples of the present invention, Staphylococcus aureus is used as a representative model of bacteria. However, fungi (bacteria or fungi) have a common basic structure such as cell membrane, cell wall and nucleic acid. Hypochlorous acid denatures membrane proteins present in the cell membrane or cell wall, or passes through the cell membrane to denature nucleic acids in the cell to achieve a sterilization effect. Therefore, it is obvious that it is effective even for bacteria other than Staphylococcus aureus.

[0159] In addition, for viruses, hypochlorous acid also achieves an inactivation effect by denaturing the envelope or the membrane protein present in the envelope, or by passing through the envelope and the capsid to denature the internal nucleic acid. In the embodiments of the present invention, Escherichia coli phage MS2 is used as a representative model of the virus, but Escherichia coli phage MS2 is a virus without an envelope. Even so, sufficient virus inactivation effects can be confirmed in the present invention. That is, for the new coronavirus with an envelope, it can be scientifically examined whether the above effects can be achieved.

[0160]

Explanation of symbols

[0161] 1 Experimental Space

[0162] 2 front room

[0163] 3. Humidifier

[0164] 4 Circulator

[0165] 5. Sprayer

[0166] 6 Compressor

[0167] 7 Spray port

[0168] 8 Air Sampler

[0169] 9 Sample collection port

Claims

1. A method, characterized in that It is a method for sterilizing or inactivating bacteria or viruses floating in the air, including the following steps: preparing a humidifier filled with an aqueous solution containing hypochlorous acid as a main component; and operating the humidifier to spray the aqueous solution into the space, The spraying is carried out while humidifying the space. 40 mol % or more of the chlorine in the aqueous solution is chlorine in the form of hypochlorous acid.

2. The method according to claim 1, characterized in that The proliferation of Legionella bacteria in the humidifier is inhibited.

3. The method according to claim 1 or 2, characterized in that: The humidifier is of ultrasonic type.

4. The method according to claim 1 or 2, characterized in that: The total amount of alkali metal ions and alkaline earth metal ions in the aqueous solution is less than 1.0 mEq / L.

5. The method according to claim 1 or 2, characterized in that: The total concentration of chlorine in the aqueous solution is 1.0 to 20.0 ppm.

6. The method according to claim 5, characterized in that The total concentration of chlorine in the aqueous solution is 1.0 to 5.0 ppm.

7. The method according to claim 6, characterized in that The total concentration of chlorine in the aqueous solution is 3.0 to 5.0 ppm.

8. The method according to claim 1 or 2, characterized in that: The spraying is performed while humidifying so that the relative humidity of the space is increased by 10% to 60% RH.

9. The method according to claim 1 or 2, characterized in that: The aqueous solution filled in the humidifier is replaced once a day.

10. A method of use, characterized in that: It is how to use a humidifier to suppress the growth of Legionella bacteria, An aqueous solution containing hypochlorous acid as a main component is used for humidification, and 40 mol % or more of chlorine in the aqueous solution is chlorine of hypochlorous acid.

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