JP7737662B2 - Chlorine dioxide generator - Google Patents

Description

The present invention relates to a chlorine dioxide generator, and in particular to a chlorine dioxide generator that is installed in an environment that is constantly exposed to moisture.

Chlorine dioxide gas generators used in living spaces such as the interiors of ordinary homes come in liquid, gel, granular, and other forms. Some chlorine dioxide gas generators require the user to mix the ingredients together immediately before use, while others require only an opening operation and no mixing. These are packaged in hard or soft containers for use (see Patent Documents 1 and 2, etc.). Chlorine dioxide generators are sold with labels claiming that by placing the chlorine dioxide generator in a living space such as a room or wearing it on the body, the user can disinfect the space, remove viruses from the space, and deodorize the space. However, the safety and effectiveness of these space disinfectants for users of chlorine dioxide gas have not been fully verified (see Non-Patent Documents 1 and 2, etc.).

On the other hand, practical uses of chlorine dioxide gas include sterilizing safety cabinets and decontaminating biological clean rooms, and its effectiveness has been thoroughly verified (see Patent Document 3, etc.). In other words, when the concentration and exposure time are controlled, chlorine dioxide gas can be said to be very effective.

In areas known as drain manholes and drain outlets, including bathroom hair catchers, and drain manholes and drain outlets, including kitchen mesh baskets (hereafter referred to as drain outlets, etc.), a slime called biofilm forms due to the growth of microorganisms. Biofilms have an undesirable appearance and emit an unpleasant odor. Typically, scrubbing with a brush or similar tool removes the biofilm's appearance and improves the odor. However, brushing is time-consuming, there are areas that cannot be reached with cleaning tools, and it does not suppress the growth of microorganisms and the odor.

When pipe cleaners containing sodium hypochlorite, sodium hydroxide, surfactants, etc. are injected, the disinfecting and bleaching effects result in a clean appearance and eliminate odors, but the effect is not long-lasting and there are safety issues with handling. Organic chlorine tablets are used as cleaning and disinfecting agents for kitchen drains. However, when hot water is poured onto organic chlorine tablets, the strong chlorine odor can be unpleasant, and if the tablets are submerged in water for a long period of time, the chlorine concentration can become very high.

In a relatively small, enclosed space, sterilization or deodorization is possible by designing the amount of chlorine dioxide gas released in accordance with the volume of the space. Generally, to generate chlorine dioxide, the user must mix two highly storable chemicals before use (see Patent Documents 4 and 5, etc.). This poses the risk of handling chemicals and is inconvenient to handle. According to Patent Documents 4 and 5, the two chemicals are contained in a container with a partition, and the user breaks the partition before use to mix the chemicals and generate chlorine dioxide gas. However, the complex structure inevitably leads to high manufacturing costs.

Japanese Patent Application Publication No. 11-278808 Japanese Patent Application Publication No. 1-99559 Patent No. 5639294 JP 2013-244994 A Japanese Patent Application Laid-Open No. 2006-335447

Hidekazu Nishimura, Verification of the practicality of chlorine dioxide gas-emitting formulations that claim to have virus inactivation effects - Inactivation of airborne influenza viruses at temperatures and humidity equivalent to indoor temperatures in winter, Journal of Environmental Infection, 2016, Vol. 31, no. 5 Hidekazu Nishimura, "Verification of the influenza virus inactivation and Staphylococcus aureus sterilization ability of chlorine dioxide gas-emitting formulations - Study on low humidity environmental surfaces," Journal of Environmental Infection, 2017, Vol. 32, no. 3

Subsequent intensive research led the inventor to complete a chlorine dioxide generator that continuously releases chlorine dioxide in small, recessed spaces such as drains that are relatively small and constantly exposed to moisture within human living spaces, thereby maintaining the effects of sterilizing or stabilizing microorganisms and deodorizing.

The present invention has been developed in consideration of the above points, and provides a chlorine dioxide generator that is effective in sterilizing or stabilizing microorganisms and deodorizing in environments that are constantly exposed to moisture, such as bathrooms and kitchen drains, and that also has a simplified structure and reduced manufacturing costs.

That is, the chlorine dioxide generator of the embodiment is a chlorine dioxide generator to be installed at a drain outlet, characterized in that a chlorine dioxide generator containing chlorite, a pH adjuster, and a water absorbent is contained in a container body made of a molded thermoplastic resin, one or more pores are formed in the container body, and the opening area per pore is 0.02 to ¹⁵ mm2 or less.

Furthermore, the container body of the chlorine dioxide generator is characterized by being formed by combining the openings of the first container body and the second container body.

Furthermore, the pores of the chlorine dioxide generator are formed in either the first container body or the second container body. Furthermore, the number of pores is two or more, and the pores are formed in both the first container body and the second container body.

Furthermore, the chlorine dioxide generator is characterized in that a sealing member that seals the pore is provided on the container body side of the pore. It is also characterized in that a sealing pin is provided that is inserted into the pore to seal it. Additionally, it is characterized in that a covering member that covers the pore is provided.

Furthermore, the chlorine dioxide generator is characterized in that the pH adjuster is a solid organic acid.

Furthermore, the chlorine dioxide generator is characterized in that the water-absorbing agent is a gelling agent.

Furthermore, the chlorine dioxide generator is characterized by the fact that a bulking agent is mixed into the chlorine dioxide generator.

Furthermore, the chlorine dioxide generator is characterized by the fact that a desiccant is mixed into the chlorine dioxide generator.

The chlorine dioxide generator of the present invention is a chlorine dioxide generator to be installed at a drain, and comprises a container body made of a molded thermoplastic resin that contains a chlorite, a pH adjuster, and a water absorbent. One or more pores are formed in the container body, and the opening area of each pore is 0.02 to ¹⁵ mm2 or less. Therefore, the device is effective in sterilizing or bacteriostasizing microorganisms and deodorizing in environments that are constantly exposed to moisture, such as bathroom and kitchen drains, and furthermore, the device has a simplified structure that allows for reduced manufacturing costs.

FIG. 1 is a schematic side view of a chlorine dioxide generator according to an embodiment before use. FIG. 10 is a partial cross-sectional view of a chlorine dioxide generator according to another embodiment. FIG. 10 is a partial cross-sectional view of a chlorine dioxide generator according to still another embodiment. FIG. 4 is a partially enlarged cross-sectional view of a pore and a sealing member. FIG. 4 is a partially enlarged cross-sectional view of a fine hole and a sealing pin. FIG. 2 is a partially enlarged cross-sectional view of a pore and a covering member. FIG. 2 is a cross-sectional view showing the function of pores. FIG. 1 is a schematic side view of a chlorine dioxide generator according to an embodiment in use. FIG. 1 is a cross-sectional view showing the effect of pores during use.

The configuration of a chlorine dioxide generator 1 according to an embodiment will be described using the schematic side view of Fig. 1 . The chlorine dioxide generator 1 of the illustrated embodiment has a container body 10 containing a powder, granule, crystalline, or tablet-like chlorine dioxide generating agent 15 for generating chlorine dioxide. The container body 10 of the embodiment is formed by bonding a first container body 11 and a second container body 12 together. The first container body 11 and the second container body 12 are bonded together by a flange portion 14. Chlorine dioxide gas (ClO ₂ ) produced as a result of the chemical reaction of the chlorine dioxide generating agent 15 diffuses to the outside of the container body 10 (first container body 11 in the illustration) through pores 13 formed in the container body 10. Therefore, the surrounding area around the chlorine dioxide generator 1 is exposed to the diffused chlorine dioxide gas, which may affect surrounding mold and bacteria.

The chlorine dioxide generator 1 is intended to be installed in a recessed space with an open top, such as a bathroom or kitchen drain. Chlorine dioxide is a gas heavier than air. Therefore, by installing the chlorine dioxide generator 1 in a recessed space such as a drain, the chlorine dioxide concentration in and around the drain is higher than outside, and this concentration is likely to be maintained for a long period of time. This allows chlorine dioxide to act on the inside (interior) of the drain and in the immediate vicinity, enhancing the disinfecting effect.

The chlorine dioxide generator 1 is expected to be installed in environments that are almost always exposed to water. Specifically, it can be installed in places such as a kitchen drain (inside the trash basket, above the bowl trap below the basket, or underwater next to the bowl trap), or a bathroom drain (on the wall near the hair catcher, above or inside the hair catcher, or underwater in the trap below the hair catcher).

In the case of a kitchen drain, wastewater from cooking various ingredients and wastewater from washing dishes pass through the drain. This wastewater contains a large amount of organic matter, which makes it easy for mold and bacteria to grow around the drain, causing bad odors and slime. In the case of a bathroom drain, water from the bathtub, wastewater after washing, soap, detergent, etc. pass through the drain. As a result, the area around the bathroom drain also becomes overloaded with organic matter, making it easy for mold and bacteria to grow, causing bad odors and slime. In other words, the purpose of the chlorine dioxide generator 1 is to disinfect, bacteriostatic, and deodorize recessed spaces such as drains.

For this reason, the chlorine dioxide generator 1 is installed directly in a recessed space in an excessively humid environment, such as a kitchen drain or bathroom drain. The chlorine dioxide gas emitted from the chlorine dioxide generator 1 is then continuously maintained in the recessed space in an excessively humid environment, such as a drain, thereby inhibiting the growth of mold and bacteria.

The container body 10 of the embodiment shown in Figure 1 is composed of a first container body 11 and a second container body 12, and both the first container body 11 and the second container body 12 are molded bodies made of thermoplastic resin. The resin used for the container body 10 is polyethylene, polypropylene, polystyrene, polyvinyl chloride resin, polyamide (also known as nylon resin), polyethylene terephthalate (PET resin), acrylonitrile-styrene resin (AS resin), acrylonitrile-butadiene-styrene resin (ABS resin), etc.

The container body 10 is constantly exposed to water or warm water (or boiling water in some cases). It is also affected by chlorine dioxide generated internally. Therefore, the first container body 11 and the second container body 12 have a thickness of at least 0.2 mm, preferably 0.5 to 1.5 mm. Furthermore, polypropylene is preferably used from the standpoint of temperature resistance. When molding the first container body 11 and the second container body 12, known molding methods such as injection molding, vacuum molding, and blow molding are used.

In the chlorine dioxide generator 1 of this embodiment, the first container body 11 and the second container body 12 are joined together by the flange portion 14. The joining may be achieved by heat sealing or by bonding with an adhesive. The first container body 11 and the second container body 12 are attached firmly enough that they will not separate during use.

In another embodiment of the chlorine dioxide generator 1A shown in the partial cross-sectional view of Figure 2, the container body 10a is formed by threading a container and a lid having male and female threads 31 and 32. In the chlorine dioxide generator 1A of Figure 2, the opening 17 of the first container body 11a and the opening 18 of the second container body 12a are combined with each other. Examples of container bodies 10a of this type include well-known screw-cap ointment containers. As will be described later, in the chlorine dioxide generator 1A of Figure 2, pores 13 are formed in each of the first container body 11a and the second container body 12a. Also, reference numeral 21 in the figure denotes a sealing member.

In yet another embodiment of a chlorine dioxide generator 1B shown in the partial cross-sectional view of Figure 3, the container body 10b is formed by fitting together return portions 33, 34 formed on both the first container body 12a and the second container body 12b. In the chlorine dioxide generator 1B of Figure 3, the opening 17 of the first container body 11b and the opening 18 of the second container body 12b are combined with each other. As will be described later, in the chlorine dioxide generator 1B of Figure 3, pores 13 are formed in each of the first container body 11b and the second container body 12b. Also, reference numeral 23 in the figure denotes a covering member.

The pores 13 are formed by molding with a mold during press molding or by drilling with laser light irradiation. The number of pores 13 is one or more and can be any number appropriate to the size of the container body 10. For example, the pores 13 are formed at intervals in multiple locations, e.g., three to six locations, in each of the first container body 11 and the second container body 12. Of course, they may be formed on the side surfaces, not just the top or bottom surfaces of the container body 10.

The pores 13 can function as openings, serving as a passageway for water to enter the interior of the container body 10 and as a release port for the generated chlorine dioxide. Furthermore, the properties required of the pores 13 are that the chlorine dioxide generator 15 does not easily leak from the pores 13 (openings) throughout the manufacturing, sale, and use of the chlorine dioxide generator 1, and that when the chlorine dioxide generator 1 is installed in a drain or the like, it absorbs a necessary and sufficient amount of water to form a solution for the reaction of the chlorine dioxide generator 15. Therefore, the shape of the pores 13 is not particularly limited. In addition to being circular or rectangular, they may also be slit-like shapes such as cuts made by a laser or a sharp blade.

Considering the role of the pores 13, it is desirable that the opening area per pore be 0.02 to ^{15 mm2} or less, preferably 0.02 to 12.6 ^mm2 . Even if the opening area of each pore is small, a predetermined opening area can be achieved by adding multiple pores. The total opening area of the pores 13 is adjusted depending on the size of the container body 10 itself, the amount of chlorine dioxide generator 15, the conditions of use, and the place of use.

When the opening area per pore is less than 0.02 ^mm2 , the opening area (opening amount) of the pore is extremely small and is not sufficient for water to enter due to the influence of the surface tension of water. When the opening area per pore exceeds 15 ^mm2 , although water can enter sufficiently, the opening area of the pore becomes large, and leakage of the swollen chlorine dioxide generator 15 from the pores becomes significant.

Here, the opening area per pore is limited to an upper and lower limit based on the need to simultaneously prevent water ingress and leakage of the swollen chlorine dioxide generator from the pores. In contrast, the total opening area (total opening area) is not limited to a specific upper limit, since the number of pores formed in the container body is an appropriate number.

Therefore, it is necessary to increase the opening area of the pores to facilitate the infiltration of water through the pores while also preventing leakage of the chlorine dioxide generator through the wide opening of the pores. To address this, as shown in the schematic cross-sectional view of Figure 2 and the partially enlarged cross-sectional view of Figure 4, a sealing member 21 that seals the pores is provided on the container body 10, 10a side of the pores 13, i.e., on the internal space 16 side of the container body 10, 10a.

The sealing member 21 may be made of any material with excellent water absorption, such as paper, Japanese paper, water-soluble paper, or cellophane. It may also be made of cotton or synthetic fabric. The sealing member 21 functions satisfactorily as long as it prevents leakage of the chlorine dioxide generating agent 15 when the chlorine dioxide generator 1 (1A) is not in use. As shown in the figure, the sealing member 21 is attached to the pore 13 from the side of the internal space 16. During use, after the chlorine dioxide generator 1 is placed in a drain or the like, water enters the pore 13 from the outside of the chlorine dioxide generator 1. The water that penetrates and passes through the sealing member 21 reaches the internal space 16. Naturally, the sealing member 21 is also permeable to chlorine dioxide gas.

As shown in the schematic cross-sectional view of Figure 5, another embodiment of the sealing member 21 disclosed in Figures 2 and 4 is provided with a sealing pin 22 that is inserted into the pore 13 to seal the pore 13. When the chlorine dioxide generator 1 is in use, the sealing pin 22 is pulled out, exposing the pore 13. When using the sealing pin 22, the opening area of each pore can be increased, making it suitable for cases where efficient water absorption into the pores is required.

Furthermore, as shown in the cross-sectional schematic diagram of FIG. 6, a covering member 23 is provided on the outside of the container body 10 (10a, 10b), i.e., on the outside of the first container body 11 (11a, 10b) in the illustration, to cover the pores 13 from the outside. The covering member 23 may be an adhesive film seal made of PET resin, polyvinyl chloride resin, or the like, or a shrink-wrap film made of a thermoplastic resin such as polypropylene. The adhesive seal or shrink-wrap film is peeled off when the chlorine dioxide generator 1 is used, exposing the pores 13. Additionally, the covering member 23 may be a film made of a water-soluble resin such as polyvinyl alcohol, or a seal made of water-soluble paper. In the case of a water-soluble resin film, it may be peeled off or left as is.

In the chlorine dioxide generator 1 shown in Figure 1, the pores 13 are formed in the first container body 11 of the container main body 10. Of course, it is also possible to form the pores 13 in the second container body 12, as opposed to the illustrated configuration. Furthermore, the pores 13 may be formed in both the first container body 11 and the second container body 12 (see Figures 2 and 3 above).

In particular, when the pore 13 is provided on the lower side of the container body 10 of the chlorine dioxide generator 1 (1A) (on the side of the second container body 12 in Figure 1), the sealing member 21, sealing pin 22, and covering member 23 are highly effective in preventing leakage of the chlorine dioxide generator 15. In addition to the structure that seals the pore shown in the figure, a sliding cover member (not shown) may be provided on the outside of the pore to open the pore during use.

The chlorine dioxide generator 15 housed in the container body 10 of the chlorine dioxide generator 1 contains a composition that includes chlorite, a pH adjuster, and a water absorbent. Furthermore, the chlorine dioxide generator 15 is blended with a bulking agent and a desiccant. The total content of the chlorine dioxide generator 15 is 5 to 30 g, depending on the volume of the installation location, and is housed in the container body 10.

Chlorite is an alkali metal salt of chlorous acid such as sodium chlorite (NaClO ₂ ) or potassium chlorite (KClO ₂ ). Chlorite is in the form of a granular, powdered, or crystalline solid for ease of storage, transportation, sale, etc. of the chlorine dioxide generator 1.

The quantitative relationship between chlorite (sodium chlorite) and pH adjuster in the chlorine dioxide generator 15 is determined by their molar ratio. Chlorine dioxide gas is generated by the reaction between chlorite and pH adjuster. Here, the pH adjuster is a solid, not a liquid. Examples include inorganic solid acids with sulfonic groups introduced onto the surface of activated carbon, such as amidosulfuric acid (sulfamic acid). Any pH adjuster may be used as long as it maintains the alkaline solution in the acidic to neutral range when chlorite (sodium chlorite) is dissolved in water.

Since pH adjusters can include solid organic acids in addition to inorganic solid acids, they are also considered acidifying agents. Solid organic acids include carboxylic acid compounds such as citric acid, oxalic acid, malic acid, succinic acid, and fumaric acid. The organic acids listed above are weak acids with a lower degree of ionization than inorganic acids. Moreover, they are also used as food additives, and are safer to handle. Furthermore, because organic acids are weak acids, they react slowly with chlorite, resulting in long-lasting chlorine dioxide generation.

In the chlorine dioxide generator 1 of this embodiment, the chlorine dioxide generator 15 in the container body 10 is characterized by not pre-holding water as a solution required for the reaction inside the container body 10. The chlorite and pH adjuster become ions in the presence of water, generating chlorine dioxide from the chlorite. Therefore, water remains essential. However, as mentioned in the background art section, it is necessary to avoid contact with water before chlorine dioxide generation (before use) and to devise a way to bring the device into contact with water only when chlorine dioxide is to be generated during use. This is because, without this, it is impossible to control the generation of chlorine dioxide.

In contrast, as shown in the enlarged cross-sectional view of Figure 7, the chlorine dioxide generator 1 of this embodiment has pores 13 formed in the container body 10. Figure 7 shows the chlorine dioxide generator 1 immediately before use or immediately after installation at the use location. As mentioned above, the chlorine dioxide generator 1 is installed near a kitchen or bathroom drain. Therefore, the area around the chlorine dioxide generator 1 is constantly overhydrated. Water outside the container body 10 can enter the internal space 16 of the container body 10 through the pores 13. This intrusion triggers the generation of chlorine dioxide from the chlorine dioxide generator 15. Furthermore, because the installation location is a high-humidity environment, the reaction proceeds through water vapor absorption, even if water does not enter the container body 10 for an extended period of time. However, unless the device absorbs water in the form of a solution, it will not be able to continuously and effectively dissipate chlorine dioxide gas. Therefore, the chlorine dioxide generator 1 must not only absorb water vapor but also absorb water in the form of a solution.

The chlorine dioxide generator 15 also contains a water-absorbing agent. The water-absorbing agent is added to retain water that has entered the container body 10 through the pores 13 inside the container body 10. Any material capable of absorbing water, such as cotton or hemp, can be used as the water-absorbing agent. Furthermore, a gelling agent is added as a preferred water-absorbing agent. The gelling agent keeps the chlorine dioxide generator 15 homogeneous and viscous after swelling due to water absorption. This makes the solution more viscous than when it is an aqueous solution. This means that the generated chlorine dioxide gas takes time to pass through, resulting in a gradual release of chlorine dioxide gas. The gelling agent is selected from polymeric water-absorbing materials such as carboxymethyl cellulose, polyvinyl alcohol, agar (agarose), xanthan gum, guar gum, and polyacrylamide.

Figure 8 is a schematic side view of the chlorine dioxide generator 1 in use. Water has entered the internal space 16 of the container body 10 through the pores 13, causing the gelling agent used as a water absorbent to swell. The swelling causes the volume of the chlorine dioxide generator 15 to expand. Figure 9 is an enlarged cross-sectional view of the vicinity of the pores 13. The chlorine dioxide generator 15 expands due to the swelling of the gelling agent, expanding in volume and reaching the vicinity of the pores 13. Therefore, taking into account the volumetric expansion of the chlorine dioxide generator 15, the filling volume of the chlorine dioxide generator 15 is limited to one-third to two-thirds, preferably one-half, of the volume of the internal space 16 of the container body 10. The swelling of the contents prevents the chlorine dioxide generator 15 from leaking out of the pores 13.

When generating chlorine dioxide gas, the presence of only chlorite and a pH adjuster in the presence of moisture is sufficient. However, the chlorine dioxide generator 1 must continue to generate chlorine dioxide gas gradually over an extended period of time. Given this requirement for sustained release, it is more desirable to suppress the reaction between chlorite and the pH adjuster. Therefore, a bulking agent, which is not directly involved in the generation of chlorine dioxide gas, is added to mitigate the reaction.

Bulking agents include various salts such as Glauber's salt (anhydrous sodium sulfate), sodium chloride, and potassium chloride. Other examples include silicates and phosphates. Bulking agents also include minerals such as bentonite, talc, and zeolites. Chlorites such as sodium chlorite are usually designated as hazardous substances. For this reason, safety is a major consideration when handling them. Therefore, bulking agents are added to limit the weight percentage of chlorites among all ingredients.

In addition, a desiccant is mixed into the chlorine dioxide generator 15. When unused, the chlorine dioxide generator 1 generates almost no chlorine dioxide due to moisture absorption, allowing it to be stored in that state. Typically, the chlorine dioxide generator 1 is packaged in a packaging material such as plastic film before distribution and display in stores. During this time, moisture may permeate the plastic film packaging and affect the device. Therefore, incorporating a desiccant is preferable to extend the shelf life of the chlorine dioxide generator 1 and prevent deterioration of the chlorine dioxide generator 15 itself. Silica gel is a good example of a desiccant. Montmorillonite, allophane, and zeolite are also used as desiccants. Zeolites and other materials are used as both desiccants and bulking agents. Because the chlorine dioxide generator 1 is intended for moisture absorption, calcium oxide is not used as a desiccant.

If necessary, an alkalizing agent is added to the chlorine dioxide generator 15. The alkalizing agent is added to maintain the alkaline state of the chlorine dioxide generator 15 in a dry state before use. Maintaining an alkaline state suppresses the decomposition of chlorite. Examples of alkalizing agents include calcium hydroxide and sodium aluminate.

[Raw materials used]
Preparation of chlorine dioxide generator: 30% by weight of 80% sodium chlorite crystals (manufactured by Nippon Carlit Co., Ltd., Silbright 80),
12% by weight of a high-molecular-weight superabsorbent resin of sodium polyacrylate superabsorbent polymer particles (Sunfresh ST-500D, manufactured by Sanyo Chemical Industries, Ltd.),
34% by weight of B-type silica gel (Toyota Chemical Industries, Ltd., B-type silica gel (mesh 30-80, 0.05-0.18 mm)
Anhydrous Glauber's salt (neutral anhydrous Glauber's salt, manufactured by Tosoh Corporation) was blended at 24% by weight to prepare a mixture.
Anhydrous citric acid was added to the mixture in an amount of 0.06% by weight based on the total weight of the mixture, and the mixture was further mixed uniformly to prepare a chlorine dioxide generator.

Container body A PET resin seasoning container ("Resin Container I") was prepared, having a lid diameter of 51 mm, a bottom diameter of 40 mm, a total height of 29.2 mm, a thickness of 0.2 mm, and a capacity of 40 mL. Holes with a diameter of 0.2 to 0.3 mm were formed on the top surface (lid) or side of the container. The diameter was confirmed using a graduated magnifying glass.

[Creation of chlorine dioxide generator]
The chlorine dioxide generator prepared above was filled to half the capacity of the container (approximately 17 g) inside the resin container I. At this time, five fine holes were formed on the top surface (lid) of the container and one on the side (generator A).

A prototype chlorine dioxide generator (Generator A) was installed on top of a hair catcher (a net used to catch hair, etc.) placed above the drain of a bathroom in a house. Three people took showers, etc. in the bathroom every day. Generator A was collected on the 20th, 29th, 36th, and 43rd days after installation, and the chlorine dioxide emission rate from Generator A was measured.

[Measurement of chlorine dioxide generation amount]
The sample to be measured (generator A) was placed in a 4.5 L synthetic resin sealed container and sealed. The container was left to stand for approximately one hour without any sudden temperature changes in the atmosphere. During this time, the gas inside the container was sampled at least twice, and the chlorine dioxide gas concentration was measured using a detector tube (Gastec Corporation, 23M). A plot of time on the horizontal axis and chlorine dioxide gas concentration on the vertical axis yields a straight line sloping upward to the right. The slope of the line, approximated by a linear equation, was used to calculate the number of milligrams of chlorine dioxide molecules emitted per hour (mg chlorine dioxide/hr) from the ideal gas equation of state. The median temperature of the ambient air during the standing time was used as the temperature to be substituted into the ideal gas equation of state. Table 1 shows the change in chlorine dioxide concentration over the cumulative number of days.

Regarding the results of generator A, chlorine dioxide generation was confirmed for approximately one month to 40 days after the start of use. Additionally, the hair catcher and drain in the bathroom where it was installed were visually inspected. Compared to before generator A was installed, the bathroom drain was less slimy, and there was also a reduction in red yeast and black mold stains and odors. Therefore, chlorine dioxide generators are effective when used in humid environments such as bathrooms that are constantly exposed to hot water.

[Measurement of water concentration of chlorine dioxide generation]
From the amount of chlorine dioxide generated by generator A after 43 days, the amount of chlorine dioxide in water can be estimated to be 0.015 ppm/L after immersion of generator A for 1 hour, and 0.075 ppm/L after immersion for 5 hours. Therefore, we confirmed whether such theoretical values could actually be reproduced by generator A.

1 L of ion-exchanged water was poured into an open container (a 2 L PET bottle with the body cut off), and Generator A, which had been in use for 43 days, was placed in it and submerged to the bottom. At this point, a depression-like space was formed 5 cm above the water surface from the top of the open container. The chlorine dioxide concentration and pH in the water were measured over time. The chlorine dioxide concentration was measured using the diethylparaphenylenediamine (DPD) method, which is used to test tap water. The results are shown in Table 2.

Actual measurements of the concentration of chlorine dioxide generated in water showed a concentration of 0.05 ppm after 5 hours of immersion, as shown in Table 2, which is considered to be roughly in line with the theoretical value. Furthermore, the chlorine dioxide concentration was maintained even after approximately 190 hours of immersion. Additionally, the pH remained in the neutral to weakly acidic range. This pH range poses no risk to metal corrosion or to human body or skin. These results demonstrate that the chlorine dioxide generator is capable of continuously emitting chlorine dioxide even after 40 days of use. Furthermore, even when placed (submerged) in stored water, the chlorine dioxide concentration does not rise significantly, providing a high level of safety.

[Comparison of concentrations at different installation locations]
Preparation of chlorine dioxide generator The chlorine dioxide generator prepared above was placed inside resin container 1 so that its volume (approximately 12 g) was 1/3 of the volume of resin container I. At this time, three fine holes (generator B) were formed on the top surface (lid) of resin container I. In order to measure the chlorine dioxide concentration at different locations, 24 mL of ion-exchanged water was placed in generator B beforehand, and the device was sealed to start the reaction.

- Reproduction of installation location A kitchen drain or similar was simulated. A 2L soft drink container (a so-called PET bottle) was cut horizontally at the body, and 1L of water was poured into the bottom of the container. A sink drain basket (made of polyethylene, 100mm diameter, 40mm depth, 110mm diameter including flange) was placed at the cut end of the container. The bottom of the drain basket was 10mm away from the water surface. Two types of installation were performed: an "in-basket installation" in which the aforementioned generator B was installed inside the drain basket, and a "floating installation" in which generator B was floated on the water surface below the drain basket.

For the "in-cage installation," chlorine dioxide concentrations were measured in the space above generator B and inside the cage, and in the area between directly below the cage and the water surface. For the "floating installation," chlorine dioxide concentrations were measured inside the cage and in the area between directly below the cage and the water surface. The chlorine dioxide concentration was measured by sampling the gas from the relevant area and using a chlorine dioxide gas detector (ATI, PortaSens II). Concentration measurements were taken 2.6 days and 5.8 days after the start of the reaction. The chlorine dioxide gas concentration measurement results are shown in Table 3.

The results in Table 3 show that chlorine dioxide generation was confirmed both inside the drain basket and when floating on the water surface. Furthermore, when the device was installed floating, more water was supplied to generator B than when it was installed inside the basket, which accelerated the reaction and increased the amount of chlorine dioxide generated. Therefore, whether the device is installed directly in a kitchen or bathroom drain or floated in a puddle inside the drain, it can be expected to have disinfecting, bacteriostatic, and deodorizing effects.

[Confirmation of microbial suppression effect]
A chlorine dioxide generator was prepared by reducing the amount of anhydrous citric acid to 0.006% by weight in the composition used for preparing the chlorine dioxide generator described above. This was enclosed in a resin container I so that its volume (approximately 12 g) was 1/3 of the container capacity. At this time, one small hole (0.6 mm in diameter) was formed in the top surface (lid) of the resin container I and one hole in the bottom surface (generator C).

0.5 g of SCD agar powder was added to 560 mL of tap water and dissolved in advance. A small amount of microbial clumps collected from a bathroom drain and grown on PDA agar medium was scraped off with a platinum loop, suspended in 9 mL of sterilized diluted water, and filtered through nonwoven fabric to obtain a filtrate. This filtrate was added to the SCD agar-containing solution described above. The resulting liquid was a light, transparent brown color. This was poured into a PET bottle and sealed, opened and stirred once a day, and stored at room temperature for 14 days to prepare the raw wastewater. This raw wastewater gave off a strong putrid odor, and numerous biofilm-like flakes had precipitated.

The biofilm-like flakes adhering to the container of raw sewage liquid mentioned above were dispersed and turned cloudy by vigorously stirring. 100 mL of this was taken and added to a PET resin container measuring 90 mm on each side and 180 mm high, along with 900 mL of tap water, to make a total volume of approximately 1000 mL. Two of these were prepared to serve as mock drains. The mixed liquid appeared slightly cloudy. A water bath was filled with water and maintained at 24.5°C from morning until evening, with the heating stopped after evening to allow the liquid temperature to drop naturally. One of the two mock drains was used as a control, and Generator C was floated in one of them, and the microbial concentration of the liquid was measured over a 10-day period.

Microbial concentration in the liquid: A Komagome pipette was inserted into the container with the simulated drain outlet, and the pipette was repeatedly sucked in and discharged to stir the liquid and suspend the flakes in the container. 1 mL of the liquid was collected from this and diluted stepwise as necessary. Then, 0.1 mL was smeared on an 85 mm diameter SCD agar plate and cultured in an incubator at 30 to 35°C for 1 to 3 days. After culture, the number of colonies that appeared on the plate was counted, and a representative value was used.

When comparing the side where heating was repeated without Generator C floating on the liquid surface with the side where heating was repeated with Generator C floating on the liquid surface, the number of colonies on the side with Generator C was approximately 1/10 or less. Therefore, although it did not achieve complete sterilization of microorganisms, it was confirmed that it had the effect of inhibiting their growth. Therefore, a bacteriostatic effect can be expected from the use of the Generator.

Furthermore, the odor caused by microbial growth was assessed using a six-level odor intensity rating system (see Table 4). On the side without generator C, a clear putrid odor was detectable directly above the container from three days after the start (rated as 2 or 3 on a six-level odor intensity scale). On the side with generator C, no putrid odor was detectable throughout the test period (rated as 0 on a six-level odor intensity scale). These results confirmed that the chlorine dioxide generator is also effective in suppressing unpleasant odors.

[Comparison with full aperture]
A 20 mL ointment container (lid: polypropylene, body: polyethylene) was prepared. Three 2.0 mm diameter holes were drilled near the center of the lid. 7.3 g of the chlorine dioxide generator prepared above was filled into the container. Ion-exchanged water was added to the container so that the saturated water absorption was 15 mL, resulting in a water absorption rate of 100% (15 mL), and the lid was then closed (opening area: 37.7 mm ² ). A comparison sample was also prepared (opening area: 962 mm ² ) in which ion-exchanged water was added to achieve a water absorption rate of 100% and the lid was not closed (body only). The opening diameter of the body was 35.0 mm. Both containers (specimens) were placed in a 3 L sealed container, and rolled up newspaper was filled in the container to absorb the generated chlorine dioxide gas.

The sealed container was stored in an incubator at 45°C and the emission rate was measured over time. The daily emission rate value (mg/h) and the elapsed time (h) were integrated to calculate the cumulative emission amount (mg). The cumulative value was plotted on the vertical axis against the number of days elapsed converted to 20°C on the horizontal axis, creating a graph showing the change in cumulative emission amount over time. The plotted values on the graph are shown in Table 5.

[Comparison results with full aperture]
When comparing the results from 10 to 50 days at 20°C with a water absorption rate of 100%, if the opening area is extremely large, the cumulative chlorine dioxide gas emission rate decreases to about half. This suggests that the sterilization, bacteriostasis, and deodorization effects will be reduced. Therefore, the maximum opening area can be set taking into account the desired total emission rate or the emission rate over time. Furthermore, the inventors have demonstrated that, for the same water absorption rate, there is a positive correlation between the opening area and the emission rate three days after the emission rate stabilizes. It is easy to predict that the emission rate will be higher without the lid between 0 and 10 days compared to with the lid, and it is possible that the values from 0 to 50 days will be similar. However, it is desirable to avoid making the opening too large to ensure stable emission of chlorine dioxide.

[Comparison between steam and water]
Four 0.95 mm diameter holes (opening area: 2.83 ^mm2 ) were drilled near the center of a 15 mL ointment container (lid: polypropylene, body: polyethylene). 7.3 g of the chlorine dioxide generator prepared above was filled into the container. The saturated water absorption amount at this time was 11 mL. After absorbing 11 mL of ion-exchanged water, the lid was closed and the container was placed in a 2 L sealed container, and rolled up newspaper was filled in the container to absorb the generated chlorine dioxide gas. The sealed container was stored in an incubator at 25°C.

Four similarly sized holes were drilled into an ointment container of the same shape, and 7.3 g of the chlorine dioxide generator prepared above was filled into the container. The container was then placed in a similar 2 L sealed container without allowing it to absorb water, and a beaker containing an appropriate amount of saturated saline was placed next to the ointment container inside the same sealed container, which was then sealed and stored in the same manner.

The samples were removed after 1 day (1.2 days) and 3 days (2.6 days) and the diffusion rate was measured. Three samples were prepared and the average value was calculated. Table 6 shows the diffusion rates (mg/h) for exposure to water vapor only and for 100% water absorption, converted to 20°C.

[Results of comparison between steam and water]
In the case of a container that was not allowed to absorb water, the specimen under high humidity conditions exhibited a yellowish tinge after one day at 25°C, and the emission rate was 0.6 mg/h, a satisfactory value for demonstrating sterilization, bacteriostasis, and deodorization effects. After three days, it reached 0.04 mg/h and remained at approximately 0.03 mg/h without further increase. In the case of a container that was allowed to absorb water (100% water absorption), the emission rate gradually decreased from 1.5 mg/h. The cumulative total emission amount calculated by integrating the emission rate and the number of days elapsed was approximately 7 times higher after 25 days at 20°C. Based on other experiments conducted by the inventors, an emission rate of approximately 0.02 mg/h is believed to be necessary to achieve sterilization, bacteriostasis, and deodorization effects in an actual drain outlet. Therefore, it was found that simply absorbing water vapor through the pores of a chlorine dioxide generator is not sufficient to fully demonstrate sterilization, bacteriostasis, and deodorization effects, and that it is necessary to absorb water in solution.

[Comparison of required water absorption amount]
An ointment container with a capacity of 20 mL (lid: polypropylene, body: polyethylene) was prepared, and 7.3 g of the prepared chlorine dioxide generator was filled into the container. One 0.6 mm diameter hole was formed near the center of both the lid and the body of the ointment container (Container Example 1, opening area: 0.57 mm ² ). As another example, four 0.95 mm diameter holes were formed in the lid of the ointment container (Container Example 2, opening area: 2.83 mm ² ). In this way, two types of containers with different opening areas were prepared.

Furthermore, we compared an example in which the water absorption rate was set to 100% (saturation) at the initial stage with an example in which the water absorption rate was gradually increased over time to 1, 5, 10, 30, and 60%.

When measuring the emission rate, the water absorption rate was increased stepwise over five days to 1, 5, 10, 30, and 60%. At each step, ion-exchanged water was added and the sample was left to stand at room temperature for approximately two hours to measure the emission rate. The sample was then placed in a 45°C incubator for two hours to accelerate the rate (equivalent to 11.3 hours at 20°C), removed, allowed to cool, and the emission rate was measured again. The emission rate was also measured overnight, and ion-exchanged water was added and the same procedure repeated. The temperature was converted to 20°C from the start, and the accelerated test was continued at 45°C until 16.9 days later, after which the accelerated test was continued at 35°C. The emission rate was measured over time, and the 20°C-converted progress was plotted on the horizontal axis, with the cumulative value of the integrated emission rate and number of days on the vertical axis.

Table 7 shows the change in the amount of chlorine dioxide (mg) over time, converted to 20°C, for Container Example 1 and Container Example 2, for the two systems: gradual water absorption and initial saturation.

While there is a difference in the amount of chlorine dioxide between Container Example 1 and Container Example 2, there is no significant difference in the total amount emitted. In other words, even if the water absorption rate (%/L) is low and the solution absorbs water little by little, or even if it becomes saturated early on, there is little difference in the cumulative total amount of chlorine dioxide emitted, and it is expected to be effective in all aspects of sterilization, bacteriostasis, and deodorization. Therefore, to achieve this effect, it is necessary to absorb water in solution, not absorb water vapor.

From a series of experiments, it was confirmed that when assembling a chlorine dioxide generator, a sufficient and sustainable amount of chlorine dioxide can be generated through water absorption from the outside of the container, even without holding water (as a solution) inside the container. In particular, the lower limit of the total opening area (sum of the opening areas) of the pores formed in the container is 0.02 _mm2 , preferably 0.5 ^mm2 . In addition, considering that the chlorine dioxide generator sealed in the container is in powder form, it is desirable that the opening area per pore be 15 ^mm2 or less.

[Pore size]
Several types of containers were prepared, and pores of different shapes and opening areas were formed. The leakage of the chlorine dioxide generator, which is an internal component, from the pores and the quality of water absorption were then verified. The amount of leakage was measured by tapping the container lightly and measuring the amount that spilled.

Prototype Example 1 was a "15cc ointment container," Prototype Example 2 was a "14cc PET resin container (condiment container)," Prototype Example 3 was a "15cc ointment container," Prototype Example 4 was a "20cc ointment container," Prototype Example 5 was a "14cc PET resin container (condiment container)," Prototype Example 6 was a "20cc ointment container," Prototype Example 7 was a "14cc PET resin container (condiment container)," Prototype Example 8 was a "20cc ointment container using nonwoven fabric as a sealing member," and Prototype Example 9 was a "20cc ointment container using absorbent cotton as a sealing member." Table 8 shows each prototype, its number of pores (number of openings), total opening area (sum of opening areas) ( ^mm2 ), leakage amount (mg), and water absorption rate (%/L). "Top" and "bottom" in the table refer to the orientation of the pores when measuring the water absorption rate. Prototype 1 is an example in which no pores are formed in the container. Prototype 4 is an example in which pores are formed on the top and bottom of the container. Prototypes 2, 3, 5 to 9 are examples in which pores are formed on one side of the container.

As a result, leakage increases relative to the total opening area, but water absorption improves. Therefore, by using a sealing member, it is possible to achieve both leakage suppression and water absorption while increasing the total opening area. Considering the total opening area of each prototype in the table, the upper limit of the opening area per hole is 15 mm ² , preferably 12.6 mm ² , based on the results of prototypes 7, 8, and 9. Furthermore, according to experiments conducted by the inventors, when the opening area of a single hole (circular, 4 mm diameter) exceeds 12.6 mm ² , the chlorine dioxide generator swells due to water absorption, resulting in significant blowout from the hole. Furthermore, it was confirmed that the chlorine dioxide generator inside the device is blown out by the swelling chlorine dioxide generator, causing it to flow out when the water comes into contact with the chlorine dioxide generator. From this perspective, the upper limit of the opening area per hole is 15 mm ² , preferably 12.6 mm ² or less.

[summary]
The fabrication and testing of a chlorine dioxide generator confirmed its effectiveness when installed in kitchen and bathroom drains. Kitchen and bathroom drains are constantly in contact with hot and cold water and contain an excess of organic matter, creating an environment conducive to mold and bacterial growth. In such locations, the device diffuses chlorine dioxide in a sustained, localized manner, maintaining a chlorine dioxide concentration effective for sterilization and bacteriostasis over a long period of time. Therefore, mold and bacteria are almost always exposed to the chlorine dioxide emitted from the chlorine dioxide generator, achieving sterilization, bacteriostasis, and deodorization. In particular, the water required for the chlorine dioxide reaction is supplied externally, eliminating the need for a separate water storage structure. The device's structure is simple and easy to manufacture. Furthermore, no mixing is required at the start of use, making it safe and easy to operate, even for those without a chemical background.

The chlorine dioxide generator of the present invention slowly releases chlorine dioxide under mild conditions after being installed in kitchen and bathroom drains. Even in spaces where people are present (living spaces), the unpleasant odor of chlorine dioxide gas is not felt, and the chlorine dioxide concentration in and around the drain can be maintained for an extended period of time. Therefore, it is particularly effective in combating slime and other stains caused by microorganisms in environments with excessive moisture, such as recessed spaces.

1, 1A, 1B Chlorine dioxide generator 10, 10a, 10b Container body 11, 11a, 11b First container body 12, 12a, 12b Second container body 13 Fine hole 14 Flange portion 15 Chlorine dioxide generator 16 Internal space 17 Opening of first container body 18 Opening of second container body 21 Sealing member 22 Sealing pin 23 Covering member

Claims (11)

A chlorine dioxide generator installed at a drain outlet,
The chlorine dioxide generator is
A chlorine dioxide generator containing a chlorite, a pH adjuster, and a water absorbent is accommodated in a container body made of a molded thermoplastic resin,
A chlorine dioxide generator characterized in that one or more pores are formed in the container body, and the opening area of each pore is 0.02 to ¹⁵ mm2 or less. The chlorine dioxide generator according to claim 1, wherein the container body is formed by combining the openings of a first container body and a second container body. The chlorine dioxide generator according to claim 2, wherein the pores are formed in either the first container body or the second container body. The chlorine dioxide generator according to claim 2, wherein there are two or more pores, and the pores are formed in both the first container body and the second container body. 5. The chlorine dioxide generator according to claim 1, wherein a sealing member for sealing the pore is provided on the inner space side of the container body relative to the pore. The chlorine dioxide generator according to any one of claims 1 to 4, which is provided with a sealing pin that is inserted into the hole to seal it. The chlorine dioxide generator according to any one of claims 1 to 4, further comprising a covering member that covers the pores. The chlorine dioxide generator according to any one of claims 1 to 7, wherein the pH adjuster is a solid organic acid. The chlorine dioxide generator according to any one of claims 1 to 8, wherein the water-absorbing agent is a gelling agent. The chlorine dioxide generator according to any one of claims 1 to 9, wherein the chlorine dioxide generator contains a bulking agent. The chlorine dioxide generator according to any one of claims 1 to 10, wherein the chlorine dioxide generator contains a desiccant.