JP7036360B2 - Method for manufacturing hypochlorous acid fluid - Google Patents

Description

The present invention relates to a method for producing a hypochlorous acid fluid from which alkali metal ions and alkaline earth metal ions have been removed.

Hypochlorous acid is widely used for cleaning and sterilization in the food and medical fields, and non-dissociative hypochlorous acid (HOCl) and dissociated hypochlorite ion ( ^OCl- ) are used. The abundance ratio varies depending on the pH of the aqueous solution. It is known that the non-dissociated type hypochlorous acid has a bactericidal effect, and the dissociated type hypochlorite ion has a cleaning effect.

As a method for obtaining non-dissociated hypochlorous acid, a method is known in which an acid such as hydrochloric acid is added to an aqueous solution of sodium hypochlorite and mixed to lower the pH of sodium hypochlorite. Patent Document 1 describes the production of a weakly acidic hypochlorous acid aqueous solution, which comprises a step of mixing and diluting raw water or purified water with hypochlorite to obtain a diluted solution, and a step of adding an acidic aqueous solution to the diluted solution. A method for producing a weakly acidic hypochlorous acid aqueous solution, wherein the pH of the weakly acidic hypochlorous acid aqueous solution is adjusted to 6.2 to 7 and the effective chlorine concentration is adjusted to 50 to 100 ppm in the production thereof. ing. According to this, it is possible to provide a weakly acidic sterilizing or sterilizing agent having excellent sterilizing or sterilizing performance, deodorizing performance, and detergency. However, since it is a method of mixing an acidic aqueous solution such as hydrochloric acid with a hypochlorite such as sodium hypochlorite, an excess salt is contained in the obtained aqueous solution. Therefore, when the sterilization treatment is performed, not only hypochlorous acid but also impurities such as salt remain. In addition, if the pH is lowered too much, chlorine gas will be generated, so it is necessary to consider safety.

On the other hand, an electrolysis method is known as a method for obtaining an aqueous solution of hypochlorous acid containing no salt. Patent Document 2 describes a primary electrolytic treatment step of electrolytically treating hydrochloric acid-added raw water, an intermediate dilution step of diluting the primary electrolytic treatment liquid which is the electrolytic treatment liquid obtained by the primary electrolytic treatment step with raw water, and the intermediate dilution. A method for producing hypochlorite water having a secondary electrolytic treatment step of electrolytically treating the intermediate diluted solution obtained by the step is described. According to this, since it can be diluted without using a neutralizing agent and adjusted to a slightly acidic region, the slightly acidic hypochlorous acid water after dilution has an extremely low salt content, and can be used in places where it can be used. It is said that the degree of freedom of usage is widened and the usability is excellent. However, the electrolysis method requires a device equipped with electrodes and an electrolysis tank and electric power, so that equipment costs and maintenance costs are high and the cost is high.

Further, as a method for obtaining a hypochlorous acid aqueous solution containing no salt, an ion exchange method using an ion exchange resin is known. Patent Document 3 is a method for producing a weakly acidic hypochlorite, which comprises a step of treating a hypochlorite solution with a weakly acidic ion exchanger having a buffering action at a pH higher than the pH at which chlorine gas is generated. The production method is described, and as a treatment with a weakly acidic ion exchanger, a method of passing a hypochlorite solution through a column filled with the weakly acidic ion exchanger and the like are described. According to this, it is said that a weakly acidic hypochlorous acid aqueous solution can be produced without using an acid and without lowering the pH below a pH that generates chlorine gas. However, in the ion exchange method, the ion exchange resin is consumed by the treatment, and the ion exchange resin needs to be replaced / regenerated, resulting in high cost.

Japanese Unexamined Patent Publication No. 2015-104719 Japanese Unexamined Patent Publication No. 2005-138001 Japanese Unexamined Patent Publication No. 2013-1620

The present invention has been made to solve the above problems, and a hypochlorous acid fluid having high cleanliness with extremely little residue of impurities such as salt can be continuously and easily produced at low cost without inputting energy. It is intended to provide a method of selective production.

The problem is hypochlorous acid that removes the ions from a hypochlorous acid stock solution containing hypochlorous acid and at least one ion selected from the group consisting of alkali metal ions and alkaline earth metal ions. It ’s a method of manufacturing fluid.
The hypochlorous acid stock solution is brought into contact with at least one polymer membrane selected from the group consisting of silicone rubber and polytetrafluoroethylene, and the ions are removed by allowing hypochlorous acid to permeate the polymer membrane. It is solved by providing a method for producing a hypochlorous acid fluid characterized by the above.

At this time, it is preferable that the pH of the hypochlorous acid stock solution is 2 to 10, and the concentration of hypochlorous acid (A) that has permeated the membrane and the ion concentration (B) that has permeated the membrane are The ratio (B / A) of is preferably 1/100 or less. At this time, it is preferable that the effective chlorine concentration in the obtained hypochlorous acid fluid is 0.1 mg / L to 200 g / L.

INDUSTRIAL APPLICABILITY According to the present invention, a hypochlorous acid fluid having extremely low residual impurities such as salt and high cleanliness can be continuously and selectively produced at low cost and easily without inputting energy. Therefore, it is possible to continuously release the active chlorine component. The obtained hypochlorous acid fluid can be used as a disinfectant in various states such as liquid, mist, and gaseous, and is suitably used in the food field, medical field, and the like.

It is a figure which showed the pH dependence of the permeation amount of hypochlorous acid. It is a figure which showed the dependence of the permeation amount of hypochlorous acid on the effective chlorine concentration. It is a figure which showed the hypochlorous acid concentration dependence calculated from the acid dissociation constant. It is a figure which showed the time-dependent change of the permeation amount of hypochlorous acid. It is a figure which showed the time-dependent change of the permeation amount of hypochlorous acid when the film thickness of the silicone rubber was changed. It is a figure which showed the temperature dependence of the permeation amount of hypochlorous acid. It is a figure which showed the permeability of hypochlorous acid by the immersion length of a silicone tube. It is a figure which showed the permeability of hypochlorous acid when the flow rate of the calcium hypochlorite aqueous solution was changed. It is a figure which showed the result of the bactericidal effect confirmation test of hypochlorous acid by pH. It is a figure which showed the result of the bactericidal effect confirmation test of hypochlorous acid in a gas phase.

The production method of the present invention removes the ions from a hypochlorite stock solution containing hypochlorite and at least one ion selected from the group consisting of alkali metal ions and alkaline earth metal ions. A method for producing a chlorite fluid, wherein the hypochlorite stock solution is brought into contact with at least one polymer film selected from the group consisting of silicone rubber and polytetrafluoroethylene, and the polymer film is subjected to hypochlorite. It is characterized in that the ions are removed by allowing chloric acid to permeate.

As is clear from the examples described later, by the production method of the present invention, a hypochlorous acid fluid having high cleanliness with extremely little residue of impurities such as salt can be continuously produced at low cost without inputting energy. It has become possible to manufacture in a targeted and selective manner. On the other hand, fluororubbers such as tetrafluoroethylene / propylene copolymer (TFE / P) and vinylidene fluoride / hexafluoropropylene copolymers (VDF / HFP) and ethylene / propylene / diene rubber copolymers (EPDM) were used. In this case, hypochlorous acid was not detected, and the active chlorine component could not be extracted from the hypochlorous acid stock solution. In particular, when EPDM was used, it was confirmed that the retention rate of tensile strength was reduced and that it was deteriorated by hypochlorous acid. On the other hand, by contacting the hypochlorous acid stock solution with at least one polymer membrane selected from the group consisting of silicone rubber and polytetrafluoroethylene, hypochlorous acid was not deteriorated by hypochlorous acid. It was confirmed by the present inventors that the effective chlorine component can be continuously and selectively extracted from the undiluted solution. The obtained hypochlorous acid fluid has extremely low residual impurities such as salt and has high cleanliness, so that the present invention has great significance.

The polymer film used in the present invention is at least one selected from the group consisting of silicone rubber and polytetrafluoroethylene, but from the viewpoint of more efficiently obtaining a hypochlorite fluid, a polymer made of silicone rubber. It is preferably a film, and more preferably a polymer film composed substantially only of silicone rubber.

The silicone rubber is not particularly limited, and methyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methylphenyl vinyl silicone rubber (PVMQ), fluorosilicone rubber (FVMQ) and the like can be preferably used. These may be used alone or in combination of two or more. Among them, at least one selected from the group consisting of methyl vinyl silicone rubber (VMQ) and methylphenyl vinyl silicone rubber (PVMQ) is more preferably used, and methyl vinyl silicone rubber (VMQ) is more preferably used.

The hypochlorite stock solution used in the present invention is not particularly limited, and a hypochlorite alkali metal salt, a hypochlorite alkali earth metal salt and the like can be used. As the alkali metal salt of hypochlorite, at least one selected from the group consisting of sodium hypochlorite and potassium hypochlorite is preferably used, and sodium hypochlorite is more preferably used. Further, as the hypochlorous acid alkaline earth metal salt, at least one selected from the group consisting of calcium hypochlorite and magnesium hypochlorite is preferably used, and calcium hypochlorite is more preferable. Used.

In the present invention, the pH of the hypochlorous acid stock solution is not particularly limited, but the pH is preferably in the range of 2 to 10. From the viewpoint of efficiently obtaining an effective chlorine component as a bactericidal agent, the pH is more preferably 8.5 or less, and even more preferably 7.5 or less. Similarly, from the viewpoint of efficiently obtaining an effective chlorine component as a bactericidal agent, the pH is more preferably 3 or more, and further preferably 4 or more.

The hypochlorous acid stock solution used in the present invention may have a buffering action, whereby the pH fluctuation is small and an effective chlorine component as a bactericidal agent can be efficiently obtained. As the buffer solution, a phosphate buffer solution, a citrate buffer solution, a citrate-phosphate buffer solution, a Tris buffer solution and the like can be preferably used. Two or more kinds of these buffers may be mixed and used. Among them, at least one buffer solution selected from the group consisting of a phosphate buffer solution, a citric acid buffer solution, and a citric acid-phosphate buffer solution is more preferably used. The concentration of the buffer solution is not particularly limited, but is preferably 10 mM to 1 M, and more preferably 20 mM to 500 mM.

In the production method of the present invention, the hypochlorous acid stock solution is brought into contact with at least one polymer membrane selected from the group consisting of silicone rubber and polytetrafluoroethylene, and hypochlorous acid is permeated through this polymer membrane. This is characterized by removing ions, and the ratio (B / A) of the concentration of hypochlorous acid (A) that has permeated the membrane to the ion concentration (B) that has permeated the membrane. Is preferably 1/100 or less. When the ratio (B / A) is 1/100 or less, a hypochlorous acid fluid having extremely low residual impurities such as salt and high cleanliness can be obtained. The ratio (B / A) is more preferably 1/500 or less, and further preferably 1/1000 or less. Usually, the ratio (B / A) is 1/10000 or more.

In the present invention, the hypochlorous acid stock solution is brought into contact with at least one polymer membrane selected from the group consisting of silicone rubber and polytetrafluoroethylene, and the polymer membrane is permeated with hypochlorite to allow ions. The method for removing the polymer film is not particularly limited, and a method of putting water in a container made of the polymer membrane and immersing the container in the hypochlorite stock solution may be used, or a tube made of the polymer membrane may be used. May be used by immersing the polymer in a hypochlorite stock solution and allowing water to flow through the tube. As described above, when water is circulated in the tube, the hypochlorous acid fluid can be continuously obtained. Further, a method may be used in which only the polymer film is placed in a container containing the hypochlorous acid stock solution to bring the hypochlorous acid stock solution into contact with the polymer film. In the case of such a method, hypochlorous acid may be used. It is possible to release the chlorous acid fluid into the gas phase.

In the present invention, the effective chlorine concentration in the obtained hypochlorous acid fluid is preferably 0.1 mg / L to 200 g / L. If the effective chlorine concentration is less than 0.1 mg / L, it may be insufficient for use as a bactericidal agent, more preferably 0.5 mg / L or more, and further preferably 2 mg / L or more. It is preferably 10 mg / L or more, and particularly preferably 10 mg / L or more. On the other hand, when the effective chlorine concentration exceeds 200 g / L, hypochlorous acid may be decomposed, and it is more preferably 50 g / L or less, further preferably 20 g / L or less, and 2 g / L or less. Is particularly preferable.

The hypochlorous acid fluid obtained by the present invention may be in the form of an aqueous solution such as a liquid or a mist, or may be in the form of a gas released into the gas phase. In the case of an aqueous solution, an aqueous solution of hypochlorous acid having extremely low residual impurities such as salt and high cleanliness can be obtained, and it can be suitably used as a bactericide. It is a preferable embodiment to replenish the hypochlorous acid aqueous solution thus obtained in a space sterilizer or the like, and it is also a preferable embodiment to produce the hypochlorous acid aqueous solution inside the space sterilizer or the like. Further, in the case of a gaseous state, since the active chlorine component is directly released into the gas phase, it can be suitably used for space sterilization with less influence on humidity. From this point of view, a space sterilization method using the hypochlorous acid fluid obtained by the present invention is also a preferred embodiment.

Hereinafter, the present invention will be described in more detail with reference to examples. As the silicone rubber in the examples, methyl vinyl silicone rubber (VMQ) was used.

(1) Measurement of concentration of hypochlorous acid permeated through silicone rubber Put 5 mL of pure water in a cylindrical silicone tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 120 mm) and polychlorotrifluoroethylene. It was sealed with a stopper made of (PCTFE) to form a measuring tube. A measuring tube was placed in a container containing 100 mL of a 500 mg / L sodium hypochlorite (NaOCl) aqueous solution (0.2 M phosphate buffer) and left at 40 ° C. for 24 hours. Next, the aqueous solution in the measuring tube is diluted with an NaOH aqueous solution (HOCl dissociates into OCl ⁻ ), and the absorbance at 292 nm (absorption of OCl ⁻ ) using a spectrophotometer (“UV-3100PC” manufactured by Shimadzu Corporation). Was measured. By determining the concentration of sodium hypochlorite in the measuring tube using a calibration curve prepared in advance using sodium hypochlorite (NaOCl) whose concentration is known, the concentration of hypochlorous acid that has permeated the silicone rubber can be determined. Calculated.

(2) pH dependence of permeation amount Using an aqueous solution of sodium hypochlorite prepared to pH 5.2, 5.6, 6.3, 7.2, 8.2, 9.2, and 10.0, respectively. Then, the concentration of hypochlorous acid permeated through the silicone rubber was determined by the measurement method of (1) above. As a result, it can be seen that the silicone rubber hardly permeates when the pH is 8.2 or higher. The obtained results are shown in FIG.

(3) Dependence on effective chlorine concentration The concentration of the sodium hypochlorite (NaOCl) aqueous solution prepared to pH 5 was changed, and the concentration of hypochlorous acid permeated through the silicone rubber was adjusted by the measurement method of (1) above. I asked for each. The obtained results are shown in FIG. The results of the hypochlorous acid concentration dependence calculated from the acid dissociation constant are shown in FIG. It was found that the silicone rubber permeation amount of the effective chlorine concentration depends on the HOCl concentration which is a non-dissociative type.

(4) Changes in permeation amount over time Put 5 mL of pure water in a cylindrical silicone tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 120 mm) and use a stopper made of polychlorotrifluoroethylene (PCTFE). It was sealed and used as a measuring tube. Place the measuring tube in a container containing 500 mL of 500 mg / L sodium hypochlorite aqueous solution (0.2 M phosphate buffer, pH 5) at room temperature (25 ° C) for 1 hour, 20 hours, and 50 hours, respectively. , Left for 90 hours. The concentration of hypochlorous acid permeated through the silicone rubber was determined by the measurement method (1) above, and the change in the permeation amount of hypochlorous acid permeating the silicone rubber was confirmed using the following formula (I). The obtained results are shown in FIG.

[式（Ｉ）中、Ｃ_０は容器内の初期濃度、Ｃ_ｉ（ｔ）はｔ時間後の測定用チューブ内の次亜塩素酸濃度、ｒ_０はチューブ外径の１／２、ｒ_ｉはチューブ内径の１／２、Ｄは拡散係数を表す。]

[In formula (I), C ₀ is the initial concentration in the container, C _i (t) is the hypochlorous acid concentration in the measurement tube after t hours, r ₀ is 1/2 of the outer diameter of the tube, ri _i . Is 1/2 of the inner diameter of the tube, and D is the diffusion coefficient. ]

(5) Effect of film thickness of silicone rubber 5 mL of pure water is put into a cylindrical silicone tube (inner diameter: 8 mm, length: 120 mm) having a thickness of 2 mm and 1.5 mm, respectively, and made of polychlorotrifluoroethylene (PCTFE). It was sealed with a stopper to form a measuring tube. Place the measuring tube in a container containing 1000 mL of 565 mg / L sodium hypochlorite (NaOCl) aqueous solution (0.2 M phosphate buffer, pH 5) at room temperature (25 ° C) for 67 hours and 120 hours, respectively. I left it. The concentration of hypochlorous acid permeated through the silicone rubber was determined by the measurement method of (1) above, and the change in the permeation amount of hypochlorous acid permeating the silicone rubber was confirmed using the above formula (I). The obtained results are shown in FIG.

(6) Measurement of sodium ion concentration in the tube Put 5 mL of pure water in a cylindrical silicone tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 120 mm) and make it made of polychlorotrifluoroethylene (PCTFE). It was sealed with a stopper to make a measuring tube. A measuring tube was placed in a container containing 1000 mL of a 450 mg / L sodium hypochlorite (NaOCl) aqueous solution (0.2 M phosphate buffer, pH 5) and left at 40 ° C. for 72 hours. The sodium ion concentration in the measuring tube was determined by high frequency inductively coupled plasma emission spectroscopy ("ICPS-7500" manufactured by Shimadzu Corporation). Further, the concentration of hypochlorous acid permeated through the silicone rubber was determined by the measurement method of (1) above. As a result, the concentration of sodium ion in the tube was 0.2 mg / L, and the concentration of hypochlorous acid in the tube was 390 mg / L.

(7) Measurement of concentration of sodium ion and calcium ion in the tube 50 mL of pure water was put into a cylindrical silicone tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 1000 mm), and polychlorotrifluoroethylene (polychlorotrifluoroethylene). It was sealed with a stopper made of PCTFE) to form a measuring tube. Place the measuring tube in a container containing 500 mL of an aqueous solution of calcium hypochlorite (Ca (OCl) ₂ ) with an effective chlorine concentration of 640 mg / L (0.2 M phosphate buffer, pH 5.1) at 40 ° C. It was left for 72 hours. The sodium ion concentration and the calcium ion concentration in the measuring tube were determined by high frequency inductively coupled plasma emission spectroscopy ("ICPS-7500" manufactured by Shimadzu Corporation). In addition, the concentration of hypochlorous acid was calculated using a digital residual chlorine tester "DCT-05" manufactured by TACMINA CORPORATION. As a result, the sodium ion concentration and the calcium ion concentration in the tube were less than 0.1 mg / L, and the concentration of hypochlorous acid in the tube was 480 mg / L. Next, the tube was sliced into round slices to prepare a ring-shaped test piece having a thickness of 1.2 mm. The tensile strength of the ring-shaped test piece was measured at a tensile speed of 100 mm / min using a universal material testing machine (“AG-100kNXplus” manufactured by Shimadzu Corporation). When the strengths before and after immersion were compared and the retention rate of tensile strength was calculated, it was 1.01. The results obtained are shown in Table 1.

(8) Temperature dependence of permeation amount 5 mL of pure water is put into a cylindrical silicone tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 120 mm), and a stopper made of polychlorotrifluoroethylene (PCTFE). It was sealed with and used as a measuring tube. Place the measuring tube in a container containing 100 mL of a 500 mg / L sodium hypochlorite (NaOCl) aqueous solution (0.2 M phosphate buffer, pH 5) at 4 ° C, 23 ° C, 40 ° C, and 50 ° C, respectively. It was left for 24 hours. The concentration of hypochlorous acid permeated through the silicone rubber was determined by the measurement method (1) above, and the effect of the permeation amount due to temperature was confirmed. The obtained results are shown in FIG.

(9) Permeability of fluororubber Pure water in a cylindrical fluororubber (tetrafluoroethylene / propylene copolymer (TFE / P)) tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 120 mm). Was put in 5 mL and sealed with a stopper made of polychlorotrifluoroethylene (PCTFE) to prepare a measuring tube. Place the measuring tube in a container containing 100 mL of a 500 mg / L sodium hypochlorite (NaOCl) aqueous solution (adjust the pH to 4.8 and 10.8 with 0.2 M phosphate buffer, respectively) 40. It was left at ° C for 24 hours. When the concentration of hypochlorous acid in the measuring tube was measured using a digital residual chlorine tester "DCT-05" manufactured by TACMINA CORPORATION, it was below the detection limit.

Put 5 mL of pure water in a cylindrical fluororubber (vinylidene fluoride / hexafluoropropylene copolymer (VDF / HFP)) tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 120 mm) and polychloro. It was sealed with a stopper made of trifluoroethylene (PCTFE) to form a measuring tube. Place the measuring tube in a container containing 100 mL of 640 mg / L calcium hypochlorite (Ca (OCl) ₂ ) aqueous solution (adjusted to pH 5.1 with 0.2 M phosphate buffer) and 24 at 40 ° C. I left it for a while. When the concentration of hypochlorous acid in the measuring tube was measured using a digital residual chlorine tester "DCT-05" manufactured by TACMINA CORPORATION, it was below the detection limit. Next, the tube was sliced into round slices to prepare a ring-shaped test piece having a thickness of 1.2 mm. The tensile strength of the ring-shaped test piece was measured at a tensile speed of 100 mm / min using a universal material testing machine (“AG-100kNXplus” manufactured by Shimadzu Corporation). When the strengths before and after immersion were compared and the retention rate of tensile strength was calculated, it was 1.00. The results obtained are shown in Table 1.

(10) Permeability of EPDM (Ethylene Propylene Diene Rubber Copolymer) Put 5 mL of pure water in a cylindrical EPDM tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 120 mm) and polychlorotrifluoroethylene. It was sealed with a fluoroethylene (PCTFE) stopper to form a measuring tube. Place the measuring tube in a container containing 110 mL of 640 mg / L calcium hypochlorite (Ca (OCl) ₂ ) aqueous solution (adjusted to pH 5.1 with 0.2 M phosphate buffer) and 24 at 40 ° C. I left it for a while. When the concentration of hypochlorous acid in the measuring tube was measured using a digital residual chlorine tester "DCT-05" manufactured by TACMINA CORPORATION, it was below the detection limit. Next, the tube was sliced into round slices to prepare a ring-shaped test piece having a thickness of 1.2 mm. The tensile strength of the ring-shaped test piece was measured at a tensile speed of 100 mm / min using a universal material testing machine (“AG-100kNXplus” manufactured by Shimadzu Corporation). When the strengths before and after immersion were compared and the retention rate of tensile strength was calculated, it was 0.78. The results obtained are shown in Table 1.

(11) Permeability of hypochlorous acid depending on the immersion length and flow rate of the tube A part (30 cm or 60 cm) of the silicone tube is immersed in 1 L of an aqueous solution of hypochlorite at room temperature (25 ° C.), and a liquid feed pump is used. A certain amount of pure water was flowed through a silicone tube (outer diameter 6 mm / inner diameter 4 mm). The effective chlorine concentration Ci of the water discharged from the silicone tube was measured with a digital residual chlorine tester "DCT-05" manufactured by TACMINA CORPORATION. As the aqueous solution of hypochlorite, an aqueous solution of sodium hypochlorite (NaOCl) and an aqueous solution of calcium hypochlorite (Ca (OCl) ₂ ) were used. The NaOCl aqueous solution was adjusted to pH 5 with a 0.2 M phosphate buffer solution, and the effective chlorine concentration was adjusted to 340 mg / L. The Ca (OCl) ₂ aqueous solution was adjusted to pH 5.5 with a 0.2 M phosphate buffer solution, and the effective chlorine concentration was adjusted to 640 mg / L. In the test using the NaOCl aqueous solution, the flow rate of pure water was kept constant (13 mL / min). The length of immersion of the silicone tube in the NaOCl aqueous solution was 30 cm up to 4 hours after immersion and 60 cm after 4 hours. The effective chlorine concentration Ci became stable in about 2 hours, and when the immersion length was doubled, the effective chlorine concentration Ci also doubled. The obtained results are shown in FIG. In the test using Ca (OCl) ₂ aqueous solution, the immersion length of the silicone tube was constant (30 cm), and the flow rate of pure water was 5 mL / min up to 4 hours after immersion and 10 mL / min after 4 hours. .. When the flow rate was doubled, the effective chlorine concentration Ci became about 1/2 times. The obtained results are shown in FIG.

(12) Permeability of PTFE (polytetrafluoroethylene) film A PTFE film (thickness 50 μm) is sandwiched between two stainless steel pipes with both flanges, and hypochlorite is placed in one of the pipes so that the PTFE film becomes a diaphragm. 80 mL of an aqueous solution of sodium (NaOCl) (0.2 M phosphate buffer, pH 5, effective chlorine concentration 340 mg / L) was filled, and the other pipe was filled with 80 mL of pure water. The flange side of the two pipes on which the PTFE film was not installed was closed with a blind flange. After leaving it at 40 ° C. for 48 hours, the effective chlorine concentration on the pure water side was determined by a digital residual chlorine tester "DCT-05" manufactured by TACMINA CORPORATION. As a result, the effective chlorine concentration was 0.04 mg / L.

(13) Permeability of PTFE tube 20 m of PTFE tube (outer diameter 2 mm / inner diameter 1 mm) is added to 500 mL of sodium hypochlorite (NaOCl) aqueous solution (0.2 M phosphate buffer, pH 5, effective chlorine concentration 1000 mg / L). It was immersed at room temperature (25 ° C.), and pure water was flowed at 1 mL / min with a liquid feed pump. The effective chlorine concentration of the water discharged from the PTFE tube was measured with a digital residual chlorine tester "DCT-05" manufactured by TACMINA CORPORATION. No effective chlorine was detected in the discharged liquid even after 8 hours had passed.

(14) Hypochlorous acid bactericidal effect confirmation test Soak silicone rubber in a 100 mg / L hypochlorous acid aqueous solution prepared at pH 6, 7, 8, 9, and 10 at room temperature (25 ° C) for 2 hours. I let you. The soaked silicone rubber was placed in the center of a filter that had previously retained E. coli, and left at 37 ° C. for 4 hours. Then, the filter was transferred to a standard agar medium and cultured at 37 ° C. for 24 hours. As a result, Escherichia coli was completely killed in the silicone rubber having a pH of 6 to 8. In the silicone rubber having a pH of 9, Escherichia coli near the periphery of the silicone rubber was killed, but some grown Escherichia coli was confirmed. On the other hand, in the silicone rubber having a pH of 10, Escherichia coli remained growing. The obtained results are shown in FIG.

(15) Test for confirming the bactericidal effect of hypochlorous acid in the gas phase Next, the pH was adjusted to 6 and 9 in a cylindrical silicone tube (outer diameter: 10 mm, inner diameter: 8 mm, thickness: 1 mm, length: 500 mm). 20 mL of an aqueous hypochlorous acid solution was added, and the mixture was placed in a decicator together with a filter containing E. coli in advance and left at 37 ° C. for 4 hours. Then, this filter was transferred to a standard agar medium and cultured at 37 ° C. for 24 hours. The results of the bactericidal effect on the effective chlorine concentration (mg / L) of the hypochlorous acid aqueous solution are shown in FIG.

Claims (4)

A method for producing a hypochlorous acid fluid that removes the ions from a hypochlorous acid stock solution containing hypochlorous acid and at least one ion selected from the group consisting of alkali metal ions and alkaline earth metal ions. And
A method for producing a hypochlorite fluid, which comprises contacting the hypochlorite stock solution with a polymer membrane made of silicone rubber and allowing the polymer membrane to permeate the hypochlorite to remove the ions. .. The method for producing a hypochlorous acid fluid according to claim 1, wherein the pH of the hypochlorous acid stock solution is 2 to 10. The hypochlorous acid according to claim 1 or 2, wherein the ratio (B / A) of the concentration (A) of hypochlorous acid that has permeated the membrane to the ion concentration (B) that has permeated the membrane is 1/100 or less. A method for producing a chloric acid fluid. The method for producing a hypochlorous acid fluid according to any one of claims 1 to 3, wherein the effective chlorine concentration in the obtained hypochlorous acid fluid is 0.1 mg / L to 200 g / L.

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