JP2017001908A - Method for producing hypochlorous acid aqueous solution and production device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a slightly acidic hypochlorous acid aqueous solution whose pH value can be held to the range of 5.5 to 6.5 over a long period.SOLUTION: Provided is a method for producing a hypochlorous acid aqueous solution by a production method containing: a first step where raw water is fed to a storage tank 2; a second step where an acidic aqueous solution is fed to the storage tank 2 while stirring the raw water fed to the storage tank 2 to produce a mixed aqueous solution of the raw water and the acidic aqueous solution; a third step where, after the second step, sodium hypochlorite is fed to the inside of the storage tank 2 while stirring the mixed aqueous solution to produce a hypochlorous acid aqueous solution 11 in the storage tank 2; and a fourth step where, after the third step, the feed of the acidic aqueous solution and the feed of the sodium hypochlorite are repeatedly performed in this order till the pH value of the hypochlorous acid aqueous solution 11 is stably held to a fixed value in the range of 5.5 to 6.5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a hypochlorous acid aqueous solution. Moreover, this invention relates to the manufacturing apparatus of the hypochlorous acid aqueous solution which can implement this manufacturing method.

  Conventionally, hypochlorous acid aqueous solutions have a strong sterilizing action, deodorizing action, bleaching action, etc., and are used in a wide range of fields such as sterilization and deodorization of medical instruments, daily necessities, human bodies and animals and plants. In particular, the slightly acidic (pH value: about 5.0 to 6.5) hypochlorous acid aqueous solution has the same pH value as that of human skin. It has the feature of being excellent. In addition, there is a feature that a chlorine odor peculiar to a chlorine-based disinfectant does not remain.

  Such a slightly acidic hypochlorous acid aqueous solution is generally prepared by supplying and mixing a predetermined amount of sodium hypochlorite and acid to raw water and adjusting the pH value to a range of 5.0 to 6.5. Manufactured by. Alternatively, it is produced by electrolytic treatment of hydrochloric acid or an aqueous solution in which sodium chloride is added to hydrochloric acid, and then diluting the pH value in the range of 5.0 to 6.0.

  By the way, hypochlorous acid is a very unstable substance, and is known to gradually decompose in an aqueous solution. For this reason, there exists a problem that the hypochlorous acid aqueous solution cannot maintain the effect | action over a long period of time. Also, hypochlorous acid aqueous solution is easily affected by weather conditions such as temperature and humidity, and it is difficult to control the pH value within a certain range even when the mixing ratio of raw materials is the same. There is a problem that the quality of the final product varies. Furthermore, in the production stage, toxic and corrosive chlorine gas is generated during the reaction of sodium hypochlorite with an acid or during the electrolytic treatment of hydrochloric acid, so a hypochlorous acid aqueous solution can be produced safely and stably. There is also a problem that it is difficult to do.

  In order to solve these problems, research and development of a production method and production apparatus of a slightly acidic hypochlorous acid aqueous solution have been promoted in recent years.

  For example, in Japanese Patent Application Laid-Open No. 2002-273451, when producing a hypochlorous acid aqueous solution by supplying and mixing a sodium hypochlorite aqueous solution and an acidic aqueous solution to the raw water, according to the flow rate and pH value of the raw water, A method is disclosed in which the amount of sodium hypochlorite aqueous solution and acidic aqueous solution added is adjusted and the dilution reaction rate is increased gradually or stepwise after each aqueous solution is added.

  In addition, in JP 2009-219984, in anticipation of a decrease in the concentration of sodium hypochlorite during use, sodium hypochlorite is added, and after stirring sufficiently with a circulation pump, the primary concentration is measured with a pH meter. Next, a method for producing a hypochlorous acid aqueous solution is disclosed, in which an acid such as acetic acid or hydrochloric acid is dispersedly charged into the tank, stirred sufficiently with a circulation pump, and then the concentration of the finished product is controlled with a pH meter. ing.

  Furthermore, JP-A-2011-56377 discloses sodium hypochlorite, a pH adjuster comprising acetic acid and sodium acetate having a buffering action, a sodium hypochlorite content of 76 ppm to 84 ppm, The manufacturing method of the hypochlorous acid aqueous solution which mixes so that content may be 157 ppm-173 ppm and content of sodium acetate will be 9.5 ppm-10.5 ppm is disclosed.

  According to these production methods, it is said that a hypochlorous acid aqueous solution whose pH value is controlled in a specific range can be stably obtained. However, in JP 2011-56377 A, the pH value of the obtained hypochlorous acid aqueous solution is set to 5 to 6, and it is difficult to say that the variation is sufficiently suppressed. Further, according to the experiments by the present inventors, it has been confirmed that the pH value of the aqueous hypochlorous acid solution obtained by the production methods described in these documents fluctuates over time, It is difficult to sustain the action.

  On the other hand, JP 2005-138001 A and JP 2007-283167 A disclose a method for producing a slightly acidic hypochlorous acid aqueous solution by performing various treatments after electrolytic treatment of dilute hydrochloric acid. ing. However, hypochlorous acid aqueous solutions obtained by these production methods also have a wide pH value range of 5.0 to 6.5 at the time of production, and it cannot be evaluated that the variation is sufficiently suppressed. . Moreover, since the pH value fluctuates with time as in the production methods described in JP-A-2002-27345, JP-A-2009-219984, and JP-A-2011-56377, over a long period of time, It is difficult to maintain that action.

JP 2002-273451 A JP 2009-219984 A JP 2011-56377 A JP 2005-138001 A JP 2007-283167 A

  An object of the present invention is to provide a method and an apparatus for producing a slightly acidic hypochlorous acid aqueous solution capable of maintaining a pH value at a constant value in the range of 5.5 to 6.5 over a long period of time. .

  In the method for producing a hypochlorous acid aqueous solution of the present invention, the first step of supplying raw water to the storage tank and the acidic water supplied to the storage tank while stirring the raw water supplied into the storage tank, A second step of generating a mixed aqueous solution of raw water and an acidic aqueous solution; and after the second step, while stirring the mixed aqueous solution in the storage tank, sodium hypochlorite is supplied into the storage tank, After the third step of generating the chloric acid aqueous solution and after the third step, the pH value of the aqueous hypochlorous acid solution is stably maintained at a constant value in the range of 5.5 to 6.5 for 1 minute or longer. And the fourth step of repeatedly supplying the acidic aqueous solution and the sodium hypochlorite in this order.

  The stirring is performed by using a circulation pump to draw out the raw water, the mixed aqueous solution, or the hypochlorous acid aqueous solution from the lower part in the storage tank, and then the raw water, the mixed aqueous solution, or the like from the upper part in the storage tank. It is preferable to carry out by resupplying the hypochlorous acid aqueous solution. In this case, it is more preferable that the discharge amount of the circulation pump be 50 L / min or more.

  The hypochlorous acid aqueous solution manufacturing apparatus of the present invention includes a storage tank having a stirring means, a water supply means for supplying raw water to the storage tank, a first supply means for supplying an acidic aqueous solution to the storage tank, A second supply means for supplying sodium hypochlorite to the storage tank; and hypochlorous acid produced in the storage tank by mixing a mixed aqueous solution of the raw water and the acidic aqueous solution and the sodium hypochlorite. PH value control means for measuring and controlling the pH value of the aqueous chloric acid solution, wherein the pH value control means stably stabilizes the pH value of the aqueous hypochlorous acid solution for 5.5 to 6 minutes. The supply of the acidic aqueous solution by the first supply means and the supply of sodium hypochlorite by the second supply means are repeated in this order until the constant value is maintained within a range of 5.

  The stirring means pulls out the raw water, the mixed aqueous solution or the hypochlorous acid aqueous solution in the storage tank from the lower part of the storage tank, and then extracts the raw water, the mixed aqueous solution or the next from the upper part of the storage tank. A circulation pump that re-feeds the aqueous chlorous acid solution is preferable. In this case, the discharge amount of the circulation pump is more preferably 50 L / min or more.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the slightly acidic hypochlorous acid aqueous solution which can maintain pH value to the constant value of the range of 5.5-6.5 over a long period of time can be provided. Moreover, according to this invention, the manufacturing apparatus of the slightly acidic hypochlorous acid aqueous solution which can implement such a manufacturing method can be provided. For this reason, the industrial significance of the present invention is extremely large.

FIG. 1 is a schematic cross-sectional view for explaining an apparatus for producing a hypochlorous acid aqueous solution of the present invention. FIG. 2 shows (A) a state after inoculating S. aureus in the hypochlorous acid aqueous solution of the present invention and storing it at room temperature for 1 minute, and (B) inoculating S. aureus in a physiological saline solution, It is a figure which shows the state after preserve | saving for 1 minute at room temperature. FIG. 3 shows (A) the state after inoculating Escherichia coli in the hypochlorous acid aqueous solution of the present invention and storing it for 1 minute at room temperature, and (B) inoculating Escherichia coli in purified water and storing it for 1 minute at room temperature. It is a figure which shows a back state. FIG. 4 shows (A) the state after inoculating Bacillus subtilis in the aqueous hypochlorous acid solution of the present invention and storing it at room temperature for 20 minutes, and (B) after inoculating Bacillus subtilis in purified water, It is a figure which shows the state after preserve | saving for 20 minutes at room temperature.

  The inventors of the present invention have made extensive studies on a method for producing a slightly acidic hypochlorous acid aqueous solution with little variation in pH value and capable of suppressing a change in pH value over time. As a result, the causes of the above-mentioned problems are as follows: (a) Despite the fact that hypochlorous acid is a very unstable substance, the prior art fully considers the influence of weather conditions such as temperature and humidity in the manufacturing stage. And (b) in the prior art, the pH value of the hypochlorous acid aqueous solution, which is the final product, is managed only by measuring immediately after the mixing of each component. It was concluded that there was no control over the change in pH value until the time elapses.

  As a result of further research based on these conclusions, the present inventors once generated a hypochlorous acid aqueous solution by supplying an acidic aqueous solution and sodium hypochlorite to the raw water, and then, for a certain period of time. By repeatedly supplying the acidic aqueous solution and sodium hypochlorite until the pH value until the time is stably maintained within a very narrow specific range, the above problems (a) and (b) can be solved simultaneously. And the knowledge that it can solve effectively was obtained. The present invention has been completed based on this finding.

  Hereinafter, the present invention will be described in detail by dividing it into “1. Production method of hypochlorous acid aqueous solution” and “2. Production apparatus of hypochlorous acid aqueous solution”. In addition, although this invention is not restrict | limited by the quantity of the hypochlorous acid aqueous solution manufactured at a time, below, on the assumption of industrial scale production, it uses 60L at a time using a 300L-500L storage tank. The present invention will be described in detail, taking as an example the case of producing a ~ 200 L hypochlorous acid aqueous solution.

1. Method for Producing Hypochlorous Acid Aqueous Solution (1) Method for Producing Hypochlorous Acid Aqueous Solution The method for producing a hypochlorous acid aqueous solution of the present invention includes: a) a first step of supplying raw water to a storage tank; A second step of supplying an acidic aqueous solution while stirring the raw water in the tank to produce a mixed aqueous solution of the raw water and the acidic aqueous solution; and c) after the second step, hypochlorous acid while stirring the mixed aqueous solution in the storage tank. A third step of supplying sodium acid to produce a hypochlorous acid aqueous solution; and d) after the third step, the pH value of the aqueous hypochlorous acid solution is stably 5.5 to 6. A fourth step in which the supply of the acidic aqueous solution and the supply of sodium hypochlorite are repeated in this order until a constant value in the range of 5 is maintained.

a) First Step The first step is a step of supplying raw water to the storage tank.

  The raw water is not particularly limited, but it is preferable to use pure water such as ion-exchanged water or distilled water in order to prevent impurities from being mixed.

  The total supply amount of raw water is preferably 20% to 40%, preferably 20% to 30% of the capacity of the storage tank, considering the ease of stirring and the supply amount of acidic aqueous solution and sodium hypochlorite. More preferably, it is more preferable to set it as 20%-25%.

  Further, in the first step, in order to make the temperature and pH value of the raw water uniform, the raw water in the storage tank is stirred when the amount of raw water in the storage tank becomes 20% or more of the capacity of the storage tank. It is preferable to start.

  The stirring method is not particularly limited, and for example, a method of rotating a propeller-shaped stirring blade in the storage tank, a method of using a pump, or the like can be employed. Among these, the method of re-supplying the extracted raw water from the upper part in the storage tank after extracting the raw water from the lower part in the storage tank using a circulation pump is preferable. With such a method, since the convection in the vertical direction can be generated in the raw water in the storage tank, the raw water can be uniformly stirred.

  In addition, it is preferable that the discharge amount of a circulation pump is 50 L / min or more, and it is more preferable that it is 100 L / min or more. This is because the raw water may not sufficiently convect when the discharge rate of the circulation pump is less than 50 L / min.

b) Second Step The second step is a step of generating a mixed aqueous solution of the raw water and the acidic aqueous solution by supplying the acidic aqueous solution while stirring the raw water in the storage tank after the completion of the first step.

  The acidic aqueous solution supplied in the second step is not particularly limited, and dilute hydrochloric acid, acetic acid aqueous solution, dilute sulfuric acid and the like can be used. Among these, in consideration of cost and handleability, it is preferable to use dilute hydrochloric acid, more preferably 6% by mass to 8% by mass of dilute hydrochloric acid, and more preferably 6% by mass to 7% by mass of dilute hydrochloric acid. .

  When dilute hydrochloric acid is used as the acidic aqueous solution, the total supply amount of dilute hydrochloric acid in the second step is preferably 1/650 to 1/550, and 1/620 to 1/580, where the supply amount of raw water is 100. Is more preferable and 1/600 is more preferable. If the total supply amount of dilute hydrochloric acid is out of the above range, a sufficient bactericidal action may not be obtained.

  The supply amount of diluted hydrochloric acid per unit time is preferably 28 mL / min to 38 mL / min, and more preferably 33 mL / min to 38 mL / min. By setting the supply amount per unit time in such a range, a uniform mixed aqueous solution can be generated, so that a sufficient bactericidal action can be ensured.

c) Third Step The third step is a step of generating sodium hypochlorite aqueous solution by supplying sodium hypochlorite while stirring the mixed aqueous solution in the storage tank after completion of the second step.

As described above, when sodium hypochlorite and an acidic aqueous solution are mixed, chlorine gas having toxicity and corrosiveness is generated by the following reaction. In particular, in the acidic region, a large amount of chlorine gas is generated, causing work accidents and corrosion of manufacturing equipment.
NaClO + 2HCl → NaCl + H ₂ O + Cl ₂

  On the other hand, in this invention, after supplying acidic aqueous solution to raw | natural water, generation | occurrence | production of chlorine gas is reduced by supplying sodium hypochlorite. That is, in the method of the present invention, it is possible to reduce the production of chlorine gas by suppressing the above reaction, to ensure safety, and to effectively prevent the corrosion of the manufacturing equipment.

  The method for supplying sodium hypochlorite is not particularly limited, but is usually supplied as a sodium hypochlorite aqueous solution. Under the present circumstances, it is preferable to adjust the density | concentration of sodium hypochlorite aqueous solution to 6 mass%-7 mass%, and it is more preferable to adjust to 6 mass%-6.5 mass%.

  Further, the supply amount of sodium hypochlorite in the third step is preferably 1/650 to 1/550, more preferably 1/620 to 1/580, with the total supply amount of raw water being 100. Preferably, 1/600 is more preferable. If the total supply amount of hypochlorous acid is out of the above range, a sufficient bactericidal action may not be obtained.

  The supply amount of the hypochlorous acid aqueous solution per unit time is preferably 28 mL / min to 38 mL / min, and more preferably 33 mL / min to 38 mL / min. By setting the supply amount per unit time in such a range, a uniform hypochlorous acid aqueous solution can be generated, so that a sufficient bactericidal action can be ensured.

d) Fourth Step In the fourth step, the pH value of the hypochlorous acid aqueous solution generated in the storage tank is stably in the range of 5.5 to 6.5 for 1 minute or more after the completion of the third step. Until the constant value is maintained, the acidic aqueous solution and sodium hypochlorite are repeatedly supplied in this order.

  That is, in the present invention, after the hypochlorous acid aqueous solution is once generated by the first to third steps, this hypochlorous acid is maintained until the pH value is stably maintained within a specific range for a certain time. While stirring the aqueous solution, the supply of the acidic aqueous solution and sodium hypochlorite is repeated in this order a plurality of times, preferably 5 to 15 times, more preferably 8 to 12 times. In such a manufacturing method, the hypochlorous acid aqueous solution, which is the final product, is managed not by the supply amount of the acidic aqueous solution or sodium hypochlorite, but by the pH value until a certain time elapses after mixing them. Therefore, fluctuations in pH value due to weather conditions and the like do not become a problem. Moreover, the hypochlorous acid aqueous solution obtained by this method is in a state in which the components constituting the aqueous solution are uniformly dispersed at the molecular level, so that fluctuations in pH value over time can be greatly suppressed. Moreover, in the present invention, when producing such a hypochlorous acid aqueous solution, it is not necessary to use a special apparatus, and therefore it can be widely applied to industrial scale production.

  In the fourth step, the time for measuring the fluctuation of the pH value (measurement time) is 1 minute or longer, preferably 2 minutes or longer, more preferably 3 minutes or longer. If this measurement time is less than 1 minute, the variation in the pH value of the obtained hypochlorous acid aqueous solution and the fluctuation over time cannot be sufficiently suppressed. The upper limit of the measurement time is not particularly limited, but even if it is too long, no further effect is obtained and the productivity is deteriorated. For this reason, it is preferably within 5 minutes, more preferably within 4 minutes.

  The pH value of the finally obtained hypochlorous acid aqueous solution is a constant value in the range of 5.5 to 6.5, preferably a constant value in the range of 6.0 to 6.5, more preferably It is necessary to adjust to 6.5. By adjusting the pH value of the hypochlorous acid aqueous solution to a constant value in such a range, quality variations can be suppressed while ensuring high safety and bactericidal action.

(2) Hypochlorous acid aqueous solution a) Characteristics The hypochlorous acid aqueous solution obtained as described above has a pH value of a constant value in the range of 5.5 to 6.5, preferably 6.0 to 6. It is controlled to a constant value in the range of 5, more preferably to 6.5. That is, since the pH value of the hypochlorous acid aqueous solution obtained by the present invention is almost the same as the pH value of human skin, it can be evaluated that it has very little influence on the human body and is excellent in safety. .

  In addition, effective chlorine that is a sterilizing and deodorizing component in a hypochlorous acid aqueous solution is known to vary in its abundance depending on the pH value, but a hypochlorous acid aqueous solution obtained by the production method of the present invention, Since the pH value is in the above range and the abundance of effective chlorine is 90% or more, it can be evaluated that the bactericidal action and the deodorizing action are excellent.

  In addition, in the hypochlorous acid aqueous solution obtained by the production method of the present invention, since each constituent component is uniformly dispersed at the molecular level as described above, the pH value can be maintained over a long period of time. Specifically, the aqueous hypochlorous acid solution obtained by the production method of the present invention has a pH value after storage for 7 days at room temperature and normal pressure to a constant value in the range of 5.5 to 6.5, preferably 6 It can be maintained at a constant value in the range of 0.0 to 6.5, more preferably 6.5.

  Furthermore, the hypochlorous acid aqueous solution obtained by the production method of the present invention does not oxidize (rust) the metal unlike the conventional chlorinated aqueous solution, so the load on the production equipment is small, and the running cost and maintenance cost are low. Reduction can be achieved.

b) Uses The hypochlorous acid aqueous solution obtained by the production method of the present invention is not limited in its usage, and can exhibit its effect by any usage such as spraying, dipping, and coating. it can.

  In addition, its use is not limited, and it can be used in a wide range of fields such as sterilization of hands and feet, sterilization of rooms and cooking utensils, and deodorization.

  Furthermore, the hypochlorous acid aqueous solution obtained by the production method of the present invention can exhibit a high bactericidal action against various bacteria and viruses. For example, it is possible to exert a high bactericidal action against bacteria such as E. coli (O157: H7), Staphylococcus aureus, Bacillus subtilis, and viruses such as influenza virus and norovirus.

2. Apparatus for producing hypochlorous acid aqueous solution a) Structure of apparatus for producing hypochlorous acid aqueous solution The apparatus for producing hypochlorous acid aqueous solution of the present invention is particularly limited as long as the above-described production method can be carried out. However, it is preferable to have a configuration as shown in FIG. 1 when assuming industrial scale production. That is, the hypochlorous acid aqueous solution manufacturing apparatus 1 of the present invention includes a storage tank 2 having a stirring means 3, a water supply means 5 for supplying raw water to the storage tank 2, and a first aqueous solution for supplying an acidic aqueous solution to the storage tank 2. Supply means 7, second supply means 9 for supplying sodium hypochlorite to the storage tank 2, and pH value control means for measuring and controlling the pH value of the hypochlorous acid aqueous solution 11 generated in the storage tank 2. 12 and the pH value control means 12 is controlled by the first supply means 7 until the pH value of the hypochlorous acid aqueous solution 11 is stably maintained at a constant value in the range of 5.5 to 6.5. The supply of the acidic aqueous solution and the supply of sodium hypochlorite by the second supply means 9 are repeated in this order. Such pH value control means 12 is preferably automated by a microcontroller, sequencer or the like.

b) Manufacture of hypochlorous acid aqueous solution Next, the case where the hypochlorous acid aqueous solution 11 is manufactured using this manufacturing apparatus 1 will be described. Will be omitted or simplified.

  First, the water supply valve 6 of the water supply means 5 is opened to supply raw water into the storage tank 2. At this time, when the supply amount of the raw water reaches 20% or more of the volume of the storage tank 2, the agitation means 3 (circulation pump in the illustrated example) starts operating and the circulation valves 4a and 4b are opened. . Thereafter, when the supply amount of the raw water reaches 20% to 40% of the volume of the storage tank 2, the water supply valve 6 is closed and the supply of the raw water is stopped (first step).

  Next, with the stirring means 3 operating, the first supply valve 8 of the first supply means 7 is opened, and the supply of the acidic aqueous solution is started. After supplying a predetermined amount of the acidic aqueous solution, the first supply valve 8 is closed to stop the supply of the acidic aqueous solution (second step).

  Then, the 2nd supply valve 10 of the 2nd supply means 9 is opened with the stirring means 3 operating, and supply of sodium hypochlorite aqueous solution is started. Similarly, after supplying a predetermined amount of the sodium hypochlorite aqueous solution, the second supply valve 10 is closed to stop the supply of the sodium hypochlorite aqueous solution (third step).

  In this way, by supplying and stirring the acidic aqueous solution and sodium hypochlorite to the raw water, a hypochlorous acid aqueous solution 11 is generated in the storage tank 2. At this time, the pH value of the hypochlorous acid aqueous solution 11 is measured over 1 minute or more by the pH sensor 13 provided in the pH value control means 12. At this time, an acidic aqueous solution and a sodium hypochlorite aqueous solution are supplied in this order to the hypochlorous acid aqueous solution 11 based on the fluctuation range of the measured pH value. Thereafter, this operation is repeated several times, preferably 5 to 15 times, and the pH value of the hypochlorous acid aqueous solution 11 as the final product is stably in the range of 5.5 to 6.5 over 1 minute. When the constant value is maintained, supply of all aqueous solutions is stopped (fourth step).

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Preparation of hypochlorous acid aqueous solution]
a) First Step First, raw water (ion exchange water) is supplied to the water supply means 5 of the hypochlorous acid aqueous solution manufacturing apparatus 1 shown in FIG. 1, 6 mass% dilute hydrochloric acid is supplied to the first supply means 7, and the second supply means is supplied. A 9 mass% sodium hypochlorite aqueous solution was set in 9, respectively.

  Next, the water supply valve 6 of the water supply means 5 was opened, and supply of raw water to the storage tank 2 (volume: 500 L) was started at 100 L / min. When the supply amount of raw water reached 100 L (20% of the capacity of the storage tank 2), the stirring means 3 was started and the circulation valves 4a and 4b were opened. In the present embodiment, a circulating pump having a discharge rate of 50 L / min is used as the stirring means 3, and the raw water in the storage tank 2 is drawn from the lower part of the storage tank 2 and then supplied from the upper part. Was stirred. Thereafter, when the supply amount of the raw water reached 100 L (20% of the volume of the storage tank 2), the water supply valve 6 was closed, the supply of the raw water was stopped, and the first step was completed.

b) Second Step After the completion of the first step, the first supply valve 8 of the first supply means 7 is opened with the stirring means 3 operating, and supply of dilute hydrochloric acid into the storage tank 2 is started at 38 mL / min. did. After the supply for 14 minutes, the first supply valve 8 was closed, the supply of dilute hydrochloric acid was stopped (total supply amount: 0.53 L), and the second step was completed.

c) Third step After the second step, the second supply valve 10 of the second supply unit 9 is opened in the same manner while the stirring unit 3 is in operation, and the sub-phase is added to the storage tank 2 at 38 mL / min. Supply of aqueous sodium chlorate solution was started. After supplying for 11 minutes, the second supply valve 10 was closed, supply of the sodium hypochlorite aqueous solution was stopped (total supply amount: 0.42 L), and the third step was completed.

d) Fourth Step After the completion of the third step, the pH value of the hypochlorous acid aqueous solution 11 generated in the storage tank 2 is measured over 30 minutes by the pH sensor 13 provided in the pH value control means 12. It was confirmed that it fluctuated in the range of 5.5 to 6.5. For this reason, after supplying the dilute hydrochloric acid by the first supply means 7 and the sodium hypochlorite aqueous solution by the second supply means 9 in this order to the hypochlorous acid aqueous solution 11 again, in the same manner. When the pH value of the hypochlorous acid aqueous solution 11 was measured, it was confirmed that it fluctuated in the range of 5.5 to 6.5. Thereafter, this operation was repeated 10 times. Finally, after confirming that the pH value was stably maintained at 6.5 for 3 minutes (180 seconds), the fourth step was completed.

[Evaluation of hypochlorous acid aqueous solution]
The following test was performed on the hypochlorous acid aqueous solution 11 obtained as described above, and the characteristics were evaluated.

a) Bactericidal effect test The test liquid was produced | generated by inoculating the hypochlorous acid aqueous solution 11 of a present Example with the bacterial solution of Staphylococcus aureus, Escherichia coli, or Bacillus subtilis. As a control, a test solution was produced in the same manner except that sanitary saline or purified water was used instead of the hypochlorous acid aqueous solution 11. These test solutions were stored at room temperature for a certain time, and then the viable cell count was measured. The results are shown in Table 1 and FIGS.

b) Virus Inactivity Test To the hypochlorous acid aqueous solution 11 of this example, an influenza virus suspension or a feline calicivirus (norovirus substitute virus) suspension was added and mixed to produce a working fluid. As a control, a test solution was produced in the same manner except that purified water was used instead of the hypochlorous acid aqueous solution 11. These test solutions were allowed to act at room temperature, and after 30 seconds, 1 minute, and 5 minutes, the virus infection titers of the working solutions were measured. The results are shown in Table 2.

c) Acute oral toxicity test The hypochlorous acid aqueous solution 11 of this example was administered to female rats to evaluate acute oral toxicity.

  First, a test group to which the aqueous chlorine solution of this example was administered and a control group to which water for injection was administered were set, and 5 mice were used for each group.

  After measuring the body weight of female rats in the test group and the control group fasted for 17 hours before administration, the hypochlorite aqueous solution 11 of this example was used for the test group, and water for injection was used for the control group. Forced single oral administration using a gastric tube with a dose volume of kg. The observation period was 14 days, the administration day was frequently observed, and observation was performed once a day from the next day. All female rats were necropsied at the end of the observation period, but no abnormalities were found in all female rats. In addition, body weight was measured after 7 days and 14 days after administration. The results are shown in Table 3. In addition, the body weight in Table 3 is a value represented by an average value ± standard deviation.

d) Skin primary irritation test Using the hypochlorous acid aqueous solution of this example, a skin primary irritation test using rabbits was conducted in accordance with OECD Guidelines for the Testing of Chemicals 404 (2002). Specifically, the hypochlorous acid aqueous solution 11 of this example was closed and applied to the intact and injured skin of 3 rabbits for 4 hours. As a result, all cases showed very mild erythema 1 hour after removal, but disappeared by 48 hours.

  In addition, the primary irritation index (P.1.1.) Determined according to ISO 10993-10 Biological Evaluation of Medical Devices-Part 10 (2010) was 0.1, and in the skin primary irritation test using rabbits, The aqueous hypochlorous acid solution 11 of this example was evaluated as being in the category of “no irritation”.

e) Stability Evaluation Test The stability of the hypochlorous acid aqueous solution 11 was evaluated by measuring the pH value after the hypochlorous acid aqueous solution 11 was stored at room temperature and normal pressure for 7 days. As a result, it was confirmed that the pH value of the hypochlorous acid aqueous solution 11 after 7 days was maintained at 6.5.

Production apparatus for primary hypochlorous acid solution 2 Storage tank 3 Stirring means 4a, 4b Circulating valve 5 Water supply means 6 Water supply valve 7 First supply means 8 First supply valve 9 Second supply means 10 Second supply valve 11 Hypochlorous acid Acid aqueous solution 12 pH value control means 13 pH sensor

Claims (6)

A first step of supplying raw water to the storage tank;
A second step of supplying an acidic aqueous solution to the storage tank while stirring the raw water supplied into the storage tank to produce a mixed aqueous solution of the raw water and the acidic aqueous solution;
After the second step, while stirring the mixed aqueous solution in the storage tank, the third step of supplying sodium hypochlorite into the storage tank to generate a hypochlorous acid aqueous solution;
After the third step, the supply of the acidic aqueous solution and the hypochlorous acid solution are maintained until the pH value of the aqueous hypochlorous acid solution is stably maintained at a constant value in the range of 5.5 to 6.5 for 1 minute or longer. A fourth step of repeatedly supplying sodium chlorate in this order;
A method for producing a hypochlorous acid aqueous solution.   The stirring is performed by using a circulation pump to draw out the raw water, the mixed aqueous solution or the hypochlorous acid aqueous solution from the lower part in the storage tank, and then from the upper part in the storage tank to the raw water, the mixed aqueous solution or the The manufacturing method of the hypochlorous acid aqueous solution of Claim 1 performed by supplying again the hypochlorous acid aqueous solution.   The manufacturing method of the hypochlorous acid aqueous solution of Claim 2 which makes discharge amount of the said circulation pump 50 L / min or more. A storage tank having a stirring means, a water supply means for supplying raw water to the storage tank, a first supply means for supplying an acidic aqueous solution to the storage tank, and a second supply for supplying sodium hypochlorite to the storage tank And pH value control means for measuring and controlling the pH value of the hypochlorous acid aqueous solution produced by mixing the mixed aqueous solution of the raw water and the acidic aqueous solution and the sodium hypochlorite in the storage tank. A hypochlorous acid aqueous solution production apparatus comprising:
The pH value control means is an acidic aqueous solution by the first supply means until the pH value of the hypochlorous acid aqueous solution is stably maintained at a constant value in the range of 5.5 to 6.5 for 1 minute or longer. Is a means of repeatedly supplying sodium hypochlorite by the second supply means in this order,
Equipment for producing hypochlorous acid aqueous solution.   The stirring means pulls out the raw water, the mixed aqueous solution or the hypochlorous acid aqueous solution in the storage tank from the lower part of the storage tank, and then extracts the raw water, the mixed aqueous solution or the next from the upper part of the storage tank. The apparatus for producing a hypochlorous acid aqueous solution according to claim 4, which is a circulation pump for re-supplying the aqueous chlorous acid solution.   The manufacturing method of the hypochlorous acid aqueous solution of Claim 5 whose discharge amount of the said circulation pump is 50 L / min or more.