Cleaning solution and manufacturing method therefor Download PDF

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Publication number US10194665B2 US14/915,211 US201314915211A US10194665B2 US 10194665 B2 US10194665 B2 US 10194665B2 US 201314915211 A US201314915211 A US 201314915211A US 10194665 B2 US10194665 B2 US 10194665B2 Authority Prior art keywords Prior art date Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Active

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Epios Co Ltd

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Epios Co Ltd

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2013-08-30 Application filed by Epios Co Ltd filed Critical Epios Co Ltd

2016-07-21 Publication of US20160205937A1 publication Critical patent/US20160205937A1/en

2018-12-19 Assigned to EPIOS CO., LTD. reassignment EPIOS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SHICHITANI, Yasuo

2019-02-05 Application granted granted Critical

2019-02-05 Publication of US10194665B2 publication Critical patent/US10194665B2/en

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2033-08-30 Anticipated expiration legal-status Critical

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• 238000004140 cleaning Methods 0.000 title claims abstract description 166
• 238000004519 manufacturing process Methods 0.000 title description 12
• 239000000243 solution Substances 0.000 claims abstract description 198
• 230000001954 sterilising Effects 0.000 claims abstract description 74
• 239000000460 chlorine Substances 0.000 claims abstract description 64
• 229910052801 chlorine Inorganic materials 0.000 claims abstract description 64
• ZAMOUSCENKQFHK-UHFFFAOYSA-N chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 64
• QWPPOHNGKGFGJK-UHFFFAOYSA-N Hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 claims abstract description 60
• 238000005868 electrolysis reaction Methods 0.000 claims abstract description 46
• 238000000034 method Methods 0.000 claims abstract description 40
• WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Inorganic materials Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 claims abstract description 24
• -1 hypochlorite ions Chemical class 0.000 claims abstract description 20
• GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 claims abstract description 8
• FAPWRFPIFSIZLT-UHFFFAOYSA-M sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 90
• 239000011780 sodium chloride Substances 0.000 claims description 46
• 210000000214 Mouth Anatomy 0.000 claims description 40
• SUKJFIGYRHOWBL-UHFFFAOYSA-N Sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 claims description 34
• 239000005708 Sodium hypochlorite Substances 0.000 claims description 30
• 102000004169 proteins and genes Human genes 0.000 claims description 20
• 108090000623 proteins and genes Proteins 0.000 claims description 20
• HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
• 239000008151 electrolyte solution Substances 0.000 claims description 10
• 239000012498 ultrapure water Substances 0.000 claims description 10
• 230000003247 decreasing Effects 0.000 claims 4
• 239000000654 additive Substances 0.000 claims 2
• 230000000996 additive Effects 0.000 claims 2
• 239000003002 pH adjusting agent Substances 0.000 claims 2
• 238000005406 washing Methods 0.000 abstract description 26
• 241000894006 Bacteria Species 0.000 abstract description 22
• 230000000694 effects Effects 0.000 abstract description 18
• 241000700605 Viruses Species 0.000 abstract description 6
• 239000007864 aqueous solution Substances 0.000 abstract description 6
• 230000002035 prolonged Effects 0.000 abstract description 6
• 235000002639 sodium chloride Nutrition 0.000 description 38
• XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 28
• 238000005259 measurement Methods 0.000 description 14
• 238000004659 sterilization and disinfection Methods 0.000 description 14
• 230000002378 acidificating Effects 0.000 description 10
• 238000010586 diagram Methods 0.000 description 10
• KZBUYRJDOAKODT-UHFFFAOYSA-N chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 8
• 230000000249 desinfective Effects 0.000 description 8
• 150000002500 ions Chemical class 0.000 description 8
• 230000001717 pathogenic Effects 0.000 description 6
• 244000052769 pathogens Species 0.000 description 6
• 201000008838 periodontal disease Diseases 0.000 description 6
• 239000011550 stock solution Substances 0.000 description 6
• 239000008399 tap water Substances 0.000 description 6
• 235000020679 tap water Nutrition 0.000 description 6
• 238000010998 test method Methods 0.000 description 6
• 208000002925 Dental Caries Diseases 0.000 description 4
• 229910001854 alkali hydroxide Inorganic materials 0.000 description 4
• 150000008044 alkali metal hydroxides Chemical class 0.000 description 4
• 230000015572 biosynthetic process Effects 0.000 description 4
• 238000006243 chemical reaction Methods 0.000 description 4
• 150000001875 compounds Chemical class 0.000 description 4
• 238000010790 dilution Methods 0.000 description 4
• 229910052731 fluorine Inorganic materials 0.000 description 4
• 239000011737 fluorine Substances 0.000 description 4
• YCKRFDGAMUMZLT-UHFFFAOYSA-N fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 4
• 238000005755 formation reaction Methods 0.000 description 4
• 239000007789 gas Substances 0.000 description 4
• 150000002431 hydrogen Chemical class 0.000 description 4
• 239000001257 hydrogen Substances 0.000 description 4
• 229910052739 hydrogen Inorganic materials 0.000 description 4
• MHAJPDPJQMAIIY-UHFFFAOYSA-N hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
• 230000001264 neutralization Effects 0.000 description 4
• 230000035755 proliferation Effects 0.000 description 4
• 230000002797 proteolythic Effects 0.000 description 4
• 239000003206 sterilizing agent Substances 0.000 description 4
• 238000003860 storage Methods 0.000 description 4
• 239000000126 substance Substances 0.000 description 4
• 210000004087 Cornea Anatomy 0.000 description 2
• 210000003491 Skin Anatomy 0.000 description 2
• UKLNMMHNWFDKNT-UHFFFAOYSA-M Sodium chlorite Chemical compound [Na+].[O-]Cl=O UKLNMMHNWFDKNT-UHFFFAOYSA-M 0.000 description 2
• 239000003513 alkali Substances 0.000 description 2
• 238000004061 bleaching Methods 0.000 description 2
• 239000007844 bleaching agent Substances 0.000 description 2
• OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
• 229910052799 carbon Inorganic materials 0.000 description 2
• 239000003795 chemical substances by application Substances 0.000 description 2
• 230000000052 comparative effect Effects 0.000 description 2
• 230000003750 conditioning Effects 0.000 description 2
• 230000000875 corresponding Effects 0.000 description 2
• 238000010192 crystallographic characterization Methods 0.000 description 2
• 230000001419 dependent Effects 0.000 description 2
• 238000007865 diluting Methods 0.000 description 2
• 239000003792 electrolyte Substances 0.000 description 2
• 230000002708 enhancing Effects 0.000 description 2
• 238000011156 evaluation Methods 0.000 description 2
• XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 2
• 238000006460 hydrolysis reaction Methods 0.000 description 2
• XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxyl anion Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
• 230000002452 interceptive Effects 0.000 description 2
• 238000011031 large scale production Methods 0.000 description 2
• 239000007788 liquid Substances 0.000 description 2
• 238000000691 measurement method Methods 0.000 description 2
• 239000007800 oxidant agent Substances 0.000 description 2
• 230000003647 oxidation Effects 0.000 description 2
• 238000007254 oxidation reaction Methods 0.000 description 2
• 239000001301 oxygen Substances 0.000 description 2
• MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
• 229910052760 oxygen Inorganic materials 0.000 description 2
• 238000001139 pH measurement Methods 0.000 description 2
• 230000003239 periodontal Effects 0.000 description 2
• 229960002218 sodium chlorite Drugs 0.000 description 2
• 230000001988 toxicity Effects 0.000 description 2
• 231100000419 toxicity Toxicity 0.000 description 2

Images

Classifications

• A—HUMAN NECESSITIES
• A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
• A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
• A01N59/00—Biocides, pest repellants or attractants, or plant growth regulators containing elements or inorganic compounds
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
• A61K33/00—Medicinal preparations containing inorganic active ingredients
• A61K33/20—Elemental chlorine; Inorganic compounds releasing chlorine
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
• A61K8/00—Cosmetics or similar toiletry preparations
• A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
• A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
• A61K8/20—Halogens; Compounds thereof
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
• A61P1/00—Drugs for disorders of the alimentary tract or the digestive system
• A61P1/02—Stomatological preparations, e.g. drugs for caries, aphtae, periodontitis
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
• A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
• A61P31/04—Antibacterial agents
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
• A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
• A61P31/12—Antivirals
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
• A61Q11/00—Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
• A61Q17/00—Barrier preparations; Preparations brought into direct contact with the skin for affording protection against external influences, e.g. sunlight, X-rays or other harmful rays, corrosive materials, bacteria or insect stings
• A61Q17/005—Antimicrobial preparations
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
• A61Q19/00—Preparations for care of the skin
• A61Q19/10—Washing or bathing preparations
• C—CHEMISTRY; METALLURGY
• C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
• C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
• C02F1/00—Treatment of water, waste water, or sewage
• C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
• C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
• C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
• C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
• C02F1/4674—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation with halogen or compound of halogens, e.g. chlorine, bromine
• C—CHEMISTRY; METALLURGY
• C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
• C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
• C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
• C11D7/02—Inorganic compounds
• C11D7/04—Water-soluble compounds
• C11D7/08—Acids
• C—CHEMISTRY; METALLURGY
• C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
• C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
• C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
• C11D7/02—Inorganic compounds
• C11D7/04—Water-soluble compounds
• C11D7/10—Salts
• C—CHEMISTRY; METALLURGY
• C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
• C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
• C25B1/00—Electrolytic production of inorganic compounds or non-metals
• C25B1/01—Products
• C25B1/24—Halogens or compounds thereof
• C25B1/26—Chlorine; Compounds thereof
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
• A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
• A61K2800/40—Chemical, physico-chemical or functional or structural properties of particular ingredients
• A61K2800/592—Mixtures of compounds complementing their respective functions
• A61K2800/5922—At least two compounds being classified in the same subclass of A61K8/18
• A—HUMAN NECESSITIES
• A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
• A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
• A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
• A61K2800/80—Process related aspects concerning the preparation of the cosmetic composition or the storage or application thereof
• A61K2800/83—Electrophoresis; Electrodes; Electrolytic phenomena

Abstract

The present invention has an object to provide a highly stable cleaning solution that generates a high concentration of hypochlorous acid during cleaning, and has sterilizing and washing out activity on bacteria and viruses. As means for achieving this object, a cleaning solution has been developed which is an aqueous solution containing hypochlorous acid and hypochlorite ions produced using a diaphragm-free electrolysis process. The effective residual chlorine concentration thereof and the hydrogen ion concentration exponent thereof are adjusted to a value from 500 ppm to 2000 ppm and to a value from pH 8.5 to pH 9.5, respectively. Thus, the cleaning solution remains stable for a prolonged period of time, and exhibits high sterilizing and wash-out activity during use.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT Application No. PCT/JP2013/074600, filed Aug. 30, 2013, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD BACKGROUND

Known, commonly commercially available cleaning solutions that have sterilizing activity include those containing, as the primary component, 1) aqueous hydrogen peroxide solution, 2) sodium chlorite, 3) sodium hypochlorite, and the like. Due to ease of handling or other reasons, those mainly containing sodium hypochlorite are widely used as cleaning solutions that have general sterilizing activity.

Such a cleaning solution is typically produced for use by diluting a high concentration of commercially available stock solution. These cleaning solutions are in widespread use in applications such as disinfectant solutions for hospitals, dental clinics, and the like, and as cleaning solutions for home use, as sterilizing agents, bleaching agents, and oxidizing agents. However, a stock solution adjusted so as to have a high concentration is a strong alkali, meaning that it has a high pH, and is thus hazardous upon contact with the skin etc. In addition, dilution of a stock solution to a suitable pH level causes evolution of chlorine gas and the like, thereby requiring great care. Moreover, problems of toxicity, odor, and other properties thereof always pose problems in storage and management of the chemical solutions.

A sterilizing cleaning process is required in many situations in hospitals and in other facilities, and automatically-controlled conditioning apparatuses for disinfectant solution mainly containing sodium hypochlorite are also available. However, introduction of such large-scale apparatus is limited by cost and floor area, and is thus difficult.

Thus, when a sodium hypochlorite solution generally for sterilization is used as a disinfectant solution, a technique that adjusts the pH, and a technique that uses diaphragm-free or diaphragm-based electrolysis, both after dilution of an aforementioned chemically-synthesized solution, are known (Patent Literature 1).

For producing sodium hypochlorite by electrolysis process, a diaphragm-free and diaphragm-based techniques described above are known. When sodium hypochlorite is produced using a diaphragm, the negative electrode chamber and the positive electrode chamber are separated from each other by the diaphragm, permitting high concentrations of chlorine and alkali hydroxide to react with each other. Accordingly, such method is used in large-scale production of alkali hydroxide and chlorine ( Patent Literatures 2, 3, and 4).

However, since the aforementioned method involves handling of a solution containing high concentrations of chemical agents, a dedicated facility is required, which leads to complexity.

Therefore, for production of a sodium hypochlorite solution on a small scale or for home use, a production method by electrolysis of common salt etc. and water using a diaphragm-free process is known. Although the sodium hypochlorite solution produced using the aforementioned method contains a lower concentration of sodium hypochlorite than the concentration of one produced using a diaphragm-based electrolysis technique, bleaching and sterilization can be sufficiently provided. In addition, the method using a diaphragm-free process is advantageous in that production facilities can be provided with a simpler structure.

As also described above, sodium hypochlorite (NaClO) has previously been known as having sterilization efficacy, and it has previously been known that hypochlorous acid (HClO) generated by hydrolysis is the sterilizing component.

It is known that effective chlorine greatly changes its form depending on the pH level. Since it is thought that hypochlorous acid, which provides high sterilization efficacy, rapidly decreases its existing ratio by changing into hypochlorite ions (OCl—) having low sterilizing ability when the pH exceeds 7, and also taking into consideration of preventing evolution of chlorine gas in a strongly acidic pH range, a sterilizing solution is typically adjusted to a value from 3 to 7, in which hypochlorous acid is said to be present in a high existing ratio (Patent Literature 1)

Thus, a generally-used neutral sterilizing solution for dental unit has a pH of from 6.5 to 7.0, and an effective chlorine concentration of from 10 to 40 ppm. A hypochlorous acid solution used for general disinfection or other purpose also has a pH of as low as from 2.2 to 7.5, and an effective chlorine concentration of as low as from 10 to 100 ppm.

However, an affected area in the oral cavity is usually covered with a smear primarily formed of protein. This presents a problem in that, without changing the conditions, application of a sterilizing solution having a predetermined pH concentration that provides sterilizing effects would not allow the sterilizing solution to act directly on the affected area by being blocked by the protein or the like covering the surface of the affected area. Another problem is that even if the sterilizing solution is applied, reaction with a smear (protein etc.) on the affected area and/or with a smear (protein etc.) in a tube of the dental unit prevents sufficient sterilizing ability from being achieved at a predetermined pH that provides sterilizing activity.

SUMMARY Technical Problem

Thus, the present invention has an object to provide a highly stable cleaning solution capable of exerting sterilizing and washing out actions on bacteria and viruses by generating not only a high concentration of hypochlorous acid but also hypochlorite ions during cleaning, even when a smear formed of protein and the like adheres to a surface to be cleaned.

Solution to Problem

The present invention has been made in view of the foregoing, and is directed to a cleaning solution that is an aqueous solution containing not only hypochlorous acid but also hypochlorite ions under normal storage conditions, which solution is stably present as a sodium hypochlorite solution having an effective residual chlorine concentration of from 500 ppm to 2000 ppm, and having a hydrogen ion concentration exponent of from pH 8.5 to pH 9.5. The cleaning solution is used as a cleaning liquid. As the cleaning solution reacts with a smear, such as protein, that covers an affected area in the oral cavity, and/or with air, protein, etc. present in the dental unit, and provides cleaning efficacy, the pH concentration decreases to a value, for example, in a range of from 5.0 to 7.0, and in turn, the existing ratio of hypochlorous acid in the cleaning solution increases, thereby enhancing the sterilizing ability of the cleaning solution, and thus enabling sterilization of periodontal disease- and dental caries-causing pathogens.

The cleaning solution is a cleaning solution wherein the concentration of NaCl for use in producing the aforementioned cleaning solution is 1% by mass or less, and thus hypochlorous acid can be more efficiently generated by performing a prolonged time of electrolysis on that solution.

The cleaning solution may be a cleaning solution wherein the pH is in a range of from 8.5 to 9.5 upon production, and as cleaning is performed in the oral cavity, the pH decreases to an acidic pH, thereby allowing sterilizing ability by hypochlorous acid to be enhanced.

Advantageous Effects of Invention

According to the present invention, a cleaning solution containing not only hypochlorous acid but also a high concentration of hypochlorite ions can easily be produced in small space, at low cost, and in a safe manner by a diaphragm-free electrolysis process. As a result, a cleaning solution production apparatus can be installed even in, for example, relatively small hospitals, dental clinics, etc. without interfering other devices, thereby permitting mouth rinsing and cleaning of treatment devices to be effectively and continuously performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram illustrating the overall appearance of a diaphragm-free electrolyzed water generator.

FIG. 2 illustrates a set of photographic images showing wash-out effect on bacteria adhered on an inner surface of a tube of a dental unit.

FIGS. 3(a) and 3(b) are each an explanatory diagram illustrating a characteristic test of a cleaning solution.

FIG. 4 is an explanatory diagram illustrating a relationship between the existing ratio and pH of hypochlorous acid, and the sterilizing effect thereof.

FIG. 5 is a diagram showing relationships between electrolysis times and effective chlorine concentrations under different concentrations of sodium chloride (NaCl).

FIG. 6 is a diagram illustrating changes in a cleaning solution according to an embodiment of the present invention when mouth washing is performed using the cleaning solution.

DETAILED DESCRIPTION

FIG. 1 illustrates an apparatus for producing a cleaning solution according to this embodiment. As shown in FIG. 1, this cleaning solution is produced by using a diaphragm-free electrolysis process. The apparatus for electrolysis used is a strongly acidic water/strongly alkaline water purifier that uses a cornea-based electrolysis process, manufactured by Aoi Engineering Inc., which was modified such that the diaphragm structure originally provided in the electrolytic cell was removed to arrange a diaphragm-free electrolytic cell, which was used.

The mechanical configuration of the other portions is the same as that for use in the diaphragm-based electrolysis process described above, and uses parts etc. that are typically used in an electrolysis process.

Specifically, the voltage during electrolysis is in a range of from 1 V to 3 V, preferably 2.5 V, and titanium platinum electrodes are used as the electrodes. Next, the electrodes of the negative electrode and the positive electrode are dipped in the aforementioned solution, and a direct current is applied between the two electrodes.

The method of producing the cleaning solution according to this embodiment is to dissolve a small amount (from 0.1% to 2%) of sodium chloride (NaCl) as the electrolyte in ultrapure water having a purity of at least 99% to produce electrolyzed water.

The ultrapure water for use in this embodiment has an electrical resistivity of 15 MΩ⋅cm or more at a water temperature of 25° C., and a total organic carbon (TOC) of less than 0.05 mg/L.

As a result, ions migrate. This causes water (H2O) to be decomposed, and at the positive electrode, oxygen (O2) gas to be evolved, and the hydrogen (H) ion concentration to be increased.

At the negative electrode, hydrogen (H2) gas is evolved, and the hydroxide (OH) ion concentration increases.

Note that, since this embodiment uses a diaphragm-free electrolysis process, chlorine evolved at the positive electrode reacts with a high concentration of sodium hydroxide generated at the negative electrode to generate sodium hypochlorite.

As a result, it is thought that chlorine and sodium hydroxide react with each other as follows:

2NaOH+Cl2→NaClO+NaCl+H2O

Experimental examples, examples, and comparative examples will be presented below to describe the present invention in more detail. It is to be appreciated, however, that the present invention is not limited to the examples described below. Note that the component content percentages in the examples all denote percentages by mass.

Example 1

The cleaning solution was used which was produced by diaphragm-free electrolysis, and had a pH of from 9.0 to 9.5, and a residual chlorine concentration of from 500 to 600 ppm. Standard tap water was used as the control sample.

A comparison was made between the condition of a biofilm on an inner surface of a tube provided for the dental unit before the test, and the condition of the biofilm in the inside of the tube two weeks after the cleaning solution was circulated.

Specifically, a comparison was made between three cases. In case 1, the sample was a control sample; in case 2, the tube was washed with the cleaning solution; and in case 3, a tube coated with fluorine-based compound was washed with the cleaning solution.

Photographic images are shown, each of which shows the condition of bacteria adhered on an inner surface of the tube after the sterilizing solution according to this embodiment was used for washing the inside of a tube of a dental medical device.

As a result, the control sample exhibited formation of a biofilm two weeks after the beginning of the test, subjected to further, recent proliferation.

In contrast, in case 2, where the inside of the tube was washed using the cleaning solution according to this Example, no formation was observed after two weeks elapsed, of a biofilm caused by bacteria such as one recognized at the beginning of the test.

In addition, as shown in case 3, replacement with the aforementioned cleaning solution and with a tube coated with fluorine-based compound resulted in no bacteria found in the tube after two weeks.

As a result, it has been verified that the aforementioned cleaning solution exfoliated the biofilm caused by bacteria formed on an inner surface of the tube, and inhibited further proliferation of bacteria.

Example 2

In this Example, a cleaning solution A was used which was produced from the cleaning solution producing apparatus described above, and had a pH of from 9.3 to 9.6, and an effective chlorine concentration of from 500 to 2000 ppm.

Mouth washing was carried out using the cleaning solution A, and comparisons were made between pHs and between residual chlorine concentrations both before mouth washing and after mouth washing of 20 seconds. In making a comparison chart, three regions were defined based on the pH and on the effective chlorine concentration, that is, a region of hypochlorous acid water 1 (pH>7.5, effective chlorine concentration: 100 to 2000 ppm), a region of electrolyzed hypochlorite water 2 (pH 7.5 to 9.0), and a region of dilute sodium hypochlorite solution 3 (pH: 2.2 to 7.5, effective chlorine concentration: 10 to 100 ppm). Tap water (pH: 6.0 to 9.0, effective chlorine concentration <1) is also shown for reference purposes.

Next, FIG. 3(a) illustrates and summarizes characteristics of the cleaning solution A used in this embodiment on the region of hypochlorous acid water 1, on the region of electrolyzed hypochlorite water 2, and on the region of dilute sodium hypochlorite solution 3. For reference purposes, a neutral sterilizing agent X for dental unit and tap water are also plotted in the chart described above, based on the respectively corresponding effective chlorine concentration and pH.

FIG. 3(b) is a chart in which these regions are plotted based on the effective chlorine concentration and pH for the cleaning solution A after mouth washing was carried out for 20 seconds using the cleaning solution A.

This shows that the cleaning solution A before the mouth washing having a relatively high pH of from 9.3 to 9.6 and an effective chlorine concentration of from 500 to 2000 ppm, has changed to a cleaning solution A having a pH of from 6.5 to 7.5 and an effective chlorine concentration of from 30 to 300 ppm.

Now with reference to FIG. 4 illustrating a relationship between the existing ratio and pH of hypochlorous acid, the existing ratio of the hypochlorous acid in the cleaning solution A relates to the change in the existing form dependent on the pH. That is, the existing ratio of hypochlorous acid having high sterilizing ability increases as the pH falls below 9 to an acidic pH. This is thought to be due to the change of the existing form from hypochlorine ions (ClO—) having low sterilizing ability to hypochlorous acid having high sterilizing ability as the pH decreases as shown by the black arrow of FIG. 4.

With this effect, and in consideration of characteristics of the cleaning solution A that inhibits evolution of chlorine gas at a strongly acidic pH, and has high sterilization efficacy, the pH of the cleaning solution A should desirably be adjusted to a pH from 3 to 7, in which the existing ratio of hypochlorous acid is high (FIG. 4).

As shown in FIGS. 3(a), 3(b), and 6, the cleaning solution A before the mouth washing of FIG. 3(a) has a high pH near 9, but after the mouth washing of FIG. 3(b) in the oral cavity, reaction between smears etc. including primarily protein in the oral cavity and the cleaning solution A reduces the pH of the cleaning solution A to pH 7 or less, and in turn, rapidly increases the existing ratio of the hypochlorous acid in the cleaning solution A from 12.5 ppm to 71 ppm. Thus, the cleaning solution A exerts a high sterilizing effect due to hypochlorous acid in oral cavity environment.

Moreover, it is advantageous in that the degree of oxidation is about pH 6 to 7 even after the 20-second mouth washing, and thus there is no concern about chlorine gas evolution.

Example 3

Relationships Between Electrolysis Times and Effective Chlorine Concentrations Under Different Concentrations of Sodium Chloride (NaCl)

The diaphragm-free electrolyzed water generator shown in FIG. 1 was used as the test apparatus. This apparatus was charged with electrolyte solution whose sodium chloride (NaCl) concentration had been appropriately adjusted, and an electrolysis process was then started. The pHs and effective chlorine concentrations of the samples were measured at each predetermined elapsed time.

In this Example, tests were carried out for cases where the sodium chloride (NaCl) concentration was 0.3% and 0.8%.

pH measurement: measurement was made using a pH meter (HM-14P of Toa Denpa Kogyo Kabushiki Gaisha) according to pH Determination in General Tests of Japanese Pharmacopoeia.

Effective chlorine: measurement was made using an effective chlorine measurement device (AQUAB AQ-102 of Sibata Scientific Technology Ltd.).

Since the measurement range of effective chlorine concentration of the aforementioned measurement device was 0 to 300 mg/kg, an appropriately-diluted solution was used for measurement.

As shown in FIG. 5, the effective chlorine concentration increased in proportion to the electrolysis time. When the sodium chloride (NaCl) concentration was 0.3%, the effective chlorine concentration exceeded a target value of 500 mg/kg at a time point of 75-minute measurement, when the pH was 9.18. When the sodium chloride (NaCl) concentration was 0.8%, no data were obtained during a time period from 0 minute to two hours (exclusive) after the beginning of the test, but at an elapsed time of two hours, the effective chlorine concentration and pH were 1440 mg/kg and 9.30, respectively. The effective chlorine concentration exceeded the target value for the cleaning solution according to the present invention.

Thus, an intended cleaning solution could be produced by using the apparatus shown in FIG. 1 to perform electrolysis of a solution having a sodium chloride (NaCl) concentration of at least 0.3% for 70 minutes or longer for producing the cleaning solution according to this Example.

When a cleaning solution produced by using the apparatus of FIG. 1 was used in cleaning of a tube of a dental treatment device, and for treatment of periodontal disease and dental caries, based on the test results of Examples 1 to 3 described above, proteolytic action of the aforementioned cleaning solution causes the biofilm adhered in the tube to be peeled off, and prevents bacteria from adhering again, and the inside of the tube can thus be maintained in a sanitary condition. In addition, a case has been reported in which taking advantage of the proteolytic action and sterilizing activity, use of the aforementioned cleaning solution for the purposes of improving the oral cavity environment of periodontal disease patients resulted in significant improvement of the oral cavity environment (not shown). This is thought to be because the sterilizing solution according to the present invention reduced the number of periodontal disease pathogens and of dental caries pathogens in the oral cavity, and degraded and removed protein adhered on surfaces of teeth.

The present invention has an object to provide a highly stable cleaning solution that generates a high concentration of hypochlorous acid during cleaning, and has sterilizing and washing out activity on bacteria and viruses. As means for achieving this object, a cleaning solution has been developed which is an aqueous solution containing hypochlorous acid and hypochlorite ions produced using a diaphragm-free electrolysis process. The effective residual chlorine concentration thereof and the hydrogen ion concentration exponent thereof are adjusted to a value from 500 ppm to 2000 ppm and to a value from pH 8.5 to pH 9.5, respectively. Thus, the cleaning solution remains stable for a prolonged period of time, and exhibits high sterilizing and wash-out activity during use.

Claims (5)

The invention claimed is:

1. A method for a cleaning solution, the method comprising:

providing a cleaning solution of hypochlorous acid and hypochlorite ions that is produced by electrolyzing an electrolyte solution for 70 minutes or longer using a diaphragm-free electrolysis process, the electrolyte solution being prepared by adding, to ultrapure water having a purity of at least 99%, 0.1% by mass to 1% by mass of sodium chloride (NaCl) only, as an additive,

wherein the cleaning solution is applied during use to a smear that at least includes protein and covers an affected area, and the hypochlorite ions react with and wash out at least part of the smear such that the affected area resists observable biofilm for at least two weeks,

wherein the diaphragm-free electrolysis process is at a voltage in a range of 1V to 3V using the electrolyte solution of only the ultrapure water and the sodium chloride.

2. The method according to claim 1,

3. The method according to claim 1, wherein the cleaning solution is produced without adding a pH adjuster.

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