JP7479624B2 - Weakly acidic hypochlorous acid disinfectant composition containing rust inhibitor - Google Patents

Description

The present invention relates to a mildly acidic hypochlorous acid disinfectant with enhanced rust prevention effects.

The form of hypochlorous acid in an aqueous solution changes depending on the pH. Specifically, in a weakly acidic region of about pH 3 to 6, most of it exists as molecular hypochlorous acid (HClO), in a basic region of pH 9 or more, it exists predominantly as dissociated hypochlorous acid ions (OCl ^- ), and in a strongly acidic region (for example, less than pH 3), the generation of chlorine molecules (Cl ₂ ) predominates as the pH decreases. Among these forms of existence, molecular hypochlorous acid (HClO) has an extremely high bactericidal effect, and it is said that its bactericidal effect is about 80 times that of ionic hypochlorous acid (OCl ^- ). Weakly acidic hypochlorous acid water with a pH of 3 to 6, which contains a large amount of molecular hypochlorous acid with such a high bactericidal effect, is also relatively safe for the human body, and is therefore used as a disinfectant or bactericide in various fields such as medicine, dentistry, agriculture, and food processing.

However, chlorine-based disinfectants and germicides are known to be corrosive to metals, and the same is true for weakly acidic hypochlorous acid. Furthermore, compared to aqueous solutions of hypochlorite salts such as sodium hypochlorite, which have a high pH, weakly acidic hypochlorous acid water is highly corrosive and corrodes metals at lower concentrations in a shorter period of time. To address this issue, germicidal cleaners with added rust inhibitors (Patent Document 1) and germicidal cleaners with added buffer agents (Patent Document 2) have been proposed.

JP 2002-161011 A International Publication No. 2006/057311

In the technologies described in Patent Documents 1 and 2, although the rust-preventing effect has been confirmed, the metal subject is mainly stainless steel, which is considered to be the least corrodible metal. Stainless steel is generally used for applications and places where rust is undesirable, but other metals may be used from the viewpoint of workability and cost. For example, in dentistry, steel is used for grinding burrs for grinding teeth. According to the study by the present inventors, when a steel grinding burr is immersed in weakly acidic hypochlorous acid water with a low concentration of effective chlorine of about 250 ppm, rust occurs in a short time even if the rust inhibitor described in Patent Document 1 is added. In addition, if the effective chlorine concentration is increased to improve the bactericidal effect, rust also occurs quickly. Therefore, it is generally necessary to use low concentrations and for short periods of time for metals that rust easily, such as steel, and as a result, the bactericidal power is sacrificed. In addition, even for metals that do not rust easily, such as stainless steel, there is a risk of rust, so it is not actively used despite being a safe and highly bactericidal bactericide.

Therefore, the present invention aims to provide a weakly acidic hypochlorous acid disinfectant with enhanced rust prevention effects.

The inventors of the present invention have focused on precipitate film-type rust inhibitors among rust inhibitors and have conducted extensive research to solve the above problems. As a result, they have discovered that by adding 200 ppm to 1600 ppm of a precipitate film-type rust inhibitor to weakly acidic hypochlorous acid water, as well as adding 100 ppm or more of polyvalent metal ions, the rust-preventing effect is improved and the time until rust occurs can be extended for metals that rust easily, such as steel, and have thus completed the present invention.

That is, the present invention is a disinfectant composition comprising weakly acidic hypochlorous acid water, characterized in that it contains (A) 200 ppm to 1600 ppm of a polyphosphate-based precipitate film type rust inhibitor or a polysilicate-based precipitate coating type rust inhibitor , and (B) 100 ppm to 780 ppm of a polyvalent metal chloride calculated as the amount of polyvalent metal ions , and has an effective chlorine concentration of 100 ppm to 2000 ppm.

The above-mentioned fungicide composition preferably does not contain an organic acid or a salt thereof .

The germicide composition of the present invention is preferably a germicide composition for use in the sterilization treatment of an article containing at least one metal selected from the group consisting of steel, cobalt chromium, silver, zinc, and brass .

The disinfectant composition of the present invention makes it possible to inhibit corrosion even in highly corrosive, weakly acidic hypochlorous acid water. Due to this corrosion-inhibiting effect, the disinfectant to which polyvalent metal ions have been added extends the time until rust occurs by more than double compared to a disinfectant to which only a precipitated film-type rust inhibitor has been added. The disinfectant of the present invention makes it possible to disinfect metals that are prone to rust, which previously required low concentrations and short treatment times, at higher concentrations and for longer immersion times. Furthermore, for metals that are resistant to rust, such as stainless steel, the risk of rusting is further reduced, broadening the scope of use.

The disinfectant composition of the present invention is capable of suppressing corrosion even in highly corrosive weakly acidic hypochlorous acid water. It is believed that this is because, by adding polyvalent metal ions in addition to a precipitated film-type rust inhibitor to the weakly acidic hypochlorous acid water, when the metal to be disinfected is immersed in the disinfectant composition, a small amount of metal ions are eluted from the metal surface, causing the precipitated film-type rust inhibitor to quickly precipitate as an insoluble component, which then deposits on the metal surface to form a film.

The pH of the weakly acidic hypochlorous acid water in the present invention is usually about 3 to 6, and within this pH range, most of the hypochlorous acid can exist as molecular hypochlorous acid in the aqueous solution. Such weakly acidic hypochlorous acid water can be produced, for example, by the electrolysis method in which an aqueous sodium chloride solution is electrolyzed, the hydrochloric acid method in which hydrochloric acid is added to a basic aqueous hypochlorite solution, or the ion exchange method in which a raw aqueous solution of a hypochlorite solution is treated with an ion exchange resin.

In the present invention, the effective chlorine concentration during use of the disinfectant composition is 100 ppm to 2000 ppm. If the effective chlorine concentration is 100 ppm or less, a sufficient disinfecting effect cannot be obtained, and if the concentration is 2000 ppm or more, not only does the disinfecting effect not change even if the concentration is increased, but the corrosive power increases, making it difficult to suppress corrosion with a rust inhibitor. From the viewpoint of more efficient disinfection, 120 ppm to 1500 ppm is preferable, and 150 to 1000 ppm is more preferable. The preparation method may be such that the weak acidic hypochlorous acid water is produced within the above range when produced, or a high concentration weak acidic hypochlorous acid water may be produced and diluted to be within the above range when the disinfectant composition is prepared.

As the precipitated film type rust inhibitor, for example , inorganic rust inhibitors include phosphate-based rust inhibitors such as phosphate, polyphosphate, phosphonate, orthophosphate; silicate-based rust inhibitors such as silicate, metasilicate, and chromate salts, which are generally sodium salts. Organic rust inhibitors include benzotriazole, tolyltriazole, mercatbenzothiazole, etc. In the disinfectant composition of the present invention, from the viewpoint of stability in weakly acidic hypochlorous acid water, use inorganic rust inhibitors such as polyphosphate-based precipitated film type rust inhibitors or polysilicate-based precipitated coating type rust inhibitors.

The amount of precipitated film-type rust inhibitor is 200 ppm to 1600 ppm. If the amount is less than 200 ppm, the film is not sufficiently formed and the rust prevention effect is not achieved. On the other hand, even if 1600 ppm or more of rust inhibitor is added, no clear improvement in the rust prevention effect can be expected. Also, from the viewpoint of efficiently achieving quicker and more uniform film formation, 220 ppm to 1200 ppm is preferable, and 240 ppm to 800 ppm is more preferable.

The (B) polyvalent metal ion of the bactericide composition of the present invention is a divalent or higher metal ion that combines with a precipitated film-type rust inhibitor to form a film on a metal surface, and examples thereof include ions of metals such as calcium, strontium, zinc, iron, aluminum, chromium, and titanium. As the polyvalent metal ion, calcium ion, strontium ion, and zinc are preferred because they are easy to obtain and easy to handle. As a method for adding polyvalent metal ions, for example, a method for dissolving metal salts or metal hydroxides in weakly acidic hypochlorous acid water, or a method for adding a solution in which polyvalent metal ions are eluted from a polyvalent metal ion-releasing filler to weakly acidic hypochlorous acid water can be considered, but as a method for adding polyvalent metal ions, a method for dissolving metal chlorides in weakly acidic hypochlorous acid water can be considered because it is easy to adjust the concentration .

The amount of polyvalent metal ions is 100 ppm or more and 780 ppm or less . If the amount is less than 100 ppm, the film formation speed is slow and the thickness is thin, so that sufficient rust prevention effect cannot be sustained. On the other hand, if the amount of polyvalent metal ions is large, a sufficient sustained effect can be obtained, but the binding between the polyvalent metal ions and the precipitated film-type rust inhibitor may progress and precipitate. Furthermore, it is necessary to wash off the components that segregate and precipitate on the metal surface. From the viewpoint of obtaining a more uniform film formation, 120 ppm to 550 ppm is preferable, and 150 ppm to 500 ppm is more preferable.

The disinfectant composition of the present invention has a high disinfecting effect and causes little damage to the object to be disinfected, and is therefore useful for disinfection in a wide range of fields, such as hospitals, food processing plants, educational facilities, and nursing homes. In addition, since it has an inhibitory effect against metal corrosion, which was a drawback of chlorine-based disinfectants, there are no particular limitations on the material of the object to be disinfected, and it can also be used to disinfect items containing metals. In particular, it can be used on steel, cobalt chrome, silver, zinc, brass, and other metals other than stainless steel, which is a metal that is resistant to rust. In particular, it is suitable for use on metals (e.g., steel, zinc, brass, etc.) that rust within 5 minutes of immersion in weakly acidic hypochlorous acid water with an effective chlorine concentration of 260 ppm.

Methods of use include, for example, spraying the area to be sterilized and then wiping it off, or immersing the object to be sterilized in the solution and then rinsing it with water.

In addition, the bactericide composition of the present invention may be mixed in advance so that all components are at a predetermined concentration, but it can also be mixed immediately before use (preparation at the time of use).As an example of preparation at the time of use, after diluting high concentration weakly acidic hypochlorous acid water to desired concentration, add necessary amount of rust inhibitor and metal chloride which is polyvalent metal ion source , and use the solution as bactericide.

The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these in any way.

First, we will explain the weakly acidic hypochlorous acid water, the precipitated film-type rust inhibitor, the metal ion compound, and the raw materials used to produce the high-concentration weakly acidic hypochlorous acid water used in the examples and comparative examples.

[Weakly acidic hypochlorous acid water]
Dentzia (Tokuyama Dental Co., Ltd.): effective chlorine concentration 743 ppm, pH 4.2
[Precipitation film type rust inhibitor]
Polyphosphate-based rust inhibitor: Orchelate NAL (sodium polyphosphate 40 wt%, water 60 wt%) (manufactured by Organo Corporation, hereinafter abbreviated as "NAL")
Polysilicate-based rust inhibitor Orchelate SIL (polysilicate sodium salt 35 wt%, water 65 wt%) (manufactured by Organo Corporation, hereinafter abbreviated as "SIL")
[Polyvalent metal ion source]
Calcium chloride (hereinafter abbreviated as "CaCl ₂ ")
Calcium hydroxide (hereinafter abbreviated as "Ca(OH) ₂ ")
Strontium chloride (hereinafter abbreviated as "SrCl ₂ ")
[Other rust inhibitors]
・Acetic acid [raw material used to produce highly concentrated weakly acidic hypochlorous acid water]
・NaClO aqueous solution with an effective chlorine concentration of 12.0% by mass (Neolux Super: supplied by Shimada Shoten)
Weakly acidic ion exchange resin Amberlite IRC-76 (H ⁺ type, manufactured by Organo Corporation, hereinafter abbreviated as "IRC76").

(1) Preparation of high concentration weakly acidic hypochlorous acid water (effective chlorine concentration 1250 ppm) The 12.0 mass% NaClO aqueous solution was diluted with ion exchange water to adjust the effective chlorine concentration to 1500 ppm, and 1200 ml of raw aqueous solution was prepared. Next, 100 ml of weakly acidic ion exchange resin IRC76 was measured, the entire amount of the raw aqueous solution was added, and the weakly acidic ion exchange resin was stirred and mixed for 30 minutes using a fluororesin stirring blade so that the weakly acidic ion exchange resin was uniformly dispersed. During stirring, the pH of the mixed solution was monitored, and stirring was stopped when the pH decreased to 5.5. After stirring, the mixture was left to stand until the resin settled, and the supernatant hypochlorous acid aqueous solution was collected by decantation into a polyethylene container through a #200 filter cloth so that the resin did not enter. To stabilize the pH, the liquid was left at room temperature for 24 hours. The weakly acidic hypochlorous acid water used in the test had an effective chlorine concentration of 1250 ppm and a pH of 4.5.

(2) Evaluation method (2-1) Measurement of effective chlorine concentration A part of the sodium hypochlorite aqueous solution and the weakly acidic hypochlorous acid water was used as a sample solution, and the sample solution was diluted with ion-exchanged water at the following dilution ratio according to the effective chlorine concentration of the raw solution to prepare a measurement sample, and the effective chlorine concentration after dilution was measured using an effective chlorine concentration measurement kit AQ-202 type (Shibata Scientific Co., Ltd.). The effective chlorine concentration of the sample solution was calculated from the measurement result and the dilution ratio.

- Effective chlorine concentration of raw solution 301 to 900 ppm: dilution ratio 3 times - Effective chlorine concentration of raw solution 901 to 3000 ppm: dilution ratio 10 times - Effective chlorine concentration of raw solution 3001 to 15000 ppm: dilution ratio 50 times - Effective chlorine concentration of raw solution 15001 to 120000 ppm: dilution ratio 500 times.

(2-2) pH Measurement The pH of the weakly acidic hypochlorous acid water and the disinfectant composition was measured using a pH meter F-55 (Horiba, Ltd.).

(2-3) Evaluation of rust 45 ml of sample solution was placed in a 50 cc glass bottle, and a dental steel bar ("Elasteel Bar (manufactured by Shofu Co., Ltd.")) or a brass plate was immersed in the solution. In the sample solution with an effective chlorine concentration of 257 ppm, the presence or absence of rust was visually confirmed at 2 minutes, 10 minutes, 20 minutes, and 30 minutes at 23°C. In addition, in the sample solution with an effective chlorine concentration of 1250 ppm, the presence or absence of rust was visually confirmed at 5 seconds, 30 seconds, 1 minute, and 1 minute and 30 seconds.
○: No rust was observed.
△: A little rust was observed.
×: Rust was clearly observed.

(2-4) Evaluation of Liquid State After preparing the germicidal composition, the state of the liquid was visually observed.

(2-5) Evaluation of storage stability 55 ml of sample solution was placed in a 100 cc glass bottle and stored at room temperature (10 to 23° C.) for one week, after which the available chlorine concentration and pH were measured to confirm any changes from the initial values.

Example 1
To 170 ml of Dentzia with an available chlorine concentration of 743 ppm, 330 ml of ion-exchanged water, 1.25 g of NAL, and 0.28 g of _CaCl2 were added, and the mixture was stirred with a stirrer for 2 minutes to prepare a disinfectant composition.
The prepared disinfectant composition was used to evaluate rust on a dental steel bur.
The composition of the disinfectant composition, pH, available chlorine concentration, and rust evaluation results are shown in Table 1.

Examples 2 to 11, 15, Comparative Examples 1 to 6, 9, 10
A fungicide composition was prepared in the same manner as in Example 1, except that the amount of ion-exchanged water used to dilute Dentzia, the amount of rust inhibitor, and the type and amount of polyvalent metal ions were changed, and rust was evaluated.
The composition, pH, available chlorine concentration, and rust evaluation results of the disinfectant composition are shown in Tables 1 and 3. The results of the storage stability evaluation of the composition of Example 15 are shown in Table 4. Example 4 is a reference example.

Example 12
(1) High-concentration weakly acidic hypochlorous acid water (effective chlorine concentration 1250 ppm) 160 ml of ion-exchanged water, 1.65 g of NAL, and 1.01 g of _CaCl2 were added to 500 ml of the weakly acidic hypochlorous acid water having an effective chlorine concentration of 1250 ppm prepared in the preparation of the weakly acidic hypochlorous acid water (effective chlorine concentration 1250 ppm), and the mixture was stirred with a stirrer for 2 minutes to prepare a disinfectant composition.
The prepared disinfectant composition was used to evaluate rust on a dental steel bur.
The composition of the disinfectant composition, pH, available chlorine concentration, and rust evaluation results are shown in Table 2.

Examples 13 and 14, Comparative Examples 7 and 8
A bactericide composition was prepared in the same manner as in Example 12, except that a weakly acidic hypochlorous acid water having an effective chlorine concentration of 1250 ppm was used, and the type and amount of the rust inhibitor and the amount of the polyvalent metal ion were changed, and the rust was evaluated.
The composition of the disinfectant composition, pH, available chlorine concentration, and rust evaluation results are shown in Table 2.

In the disinfectant composition with an effective chlorine concentration of 260 ppm, no rust was observed until 20 minutes in Examples 1 to 8. In Example 9, which contains a small amount of rust inhibitor, no rust was observed until 10 minutes, but slight rust was observed at 20 minutes. In Example 10, which contains a high concentration of rust inhibitor, and Example 11, which contains an effective chlorine concentration of 150 ppm, no rust was observed at 30 minutes. On the other hand, in Comparative Example 1, which contains only a rust inhibitor and has a low concentration, and Comparative Example 5, which does not contain any rust inhibitor, rust was clearly observed at 2 minutes. In Comparative Examples 2 and 3, which contain a high concentration of rust inhibitor, no rust was observed at 2 minutes, but slight rust was observed at 10 minutes. The same was true for Comparative Example 4, which contains a low concentration of polyvalent metal ions. In the disinfectant compositions with effective chlorine concentrations of 950 ppm and 1250 ppm, no rust was observed until 1 minute in Examples 12 to 14. On the other hand, in Comparative Example 7, which contains only a rust inhibitor, rust was observed at 30 seconds. In comparison example 8, where no rust inhibitor was added, rust was observed within 5 seconds.

Furthermore, when brass was used as the evaluation metal, as in the evaluation using steel, in Example 15, in which a rust inhibitor and polyvalent metal ions were added, rust was not observed up to 20 minutes. On the other hand, in Comparative Examples 9 and 10, in which only a rust inhibitor was used, rust was observed after 2 minutes.

Compared to a disinfectant made of weakly acidic hypochlorous acid to which only a rust inhibitor was added, the disinfectant to which polyvalent metal ions were added was able to inhibit rust for more than twice as long.
In addition, in the case of the disinfectant composition of Example 15, the available chlorine concentration and pH of the disinfectant composition of the present invention stored at room temperature for one week did not change from the initial values.

Claims (3)

A disinfectant composition comprising weakly acidic hypochlorous acid water,
(A) Polyphosphate-based precipitated film type rust inhibitor or polysilicate-based precipitated coating type rust inhibitor at 200 ppm to 1600 ppm,
(B) Polyvalent metal chlorides: 100 ppm to 780 ppm in terms of polyvalent metal ion amount
Contains
The effective chlorine concentration is 100 ppm to 2000 ppm.
A fungicide composition comprising : 10. The fungicide composition of claim 1, which does not contain an organic acid or a salt thereof. 3. The disinfectant composition according to claim 1 or 2, for use in disinfecting an article containing at least one metal selected from the group consisting of steel, cobalt chromium, silver, zinc and brass .