Method for producing hypochlorite-type hydrocalumite, and hypochlorite-type hydrocalumite

Abstract

To provide a disinfectant with immediate effectiveness and stability in a wide range of use environments such as in air, water, and underground.SOLUTION: A method for producing hypochlorite-type hydrocalumite comprises mixing hydrated lime, aluminum hydroxide with an activity index ΔM of 0.3 or more, and calcium hypochlorite in water to cause a reaction to form the hypochlorite-type hydrocalumite, wherein the hypochlorite-type hydrocalumite is represented by the chemical formula 2[Ca2Al(OH)6+](ClO)2-nH2O (n=0 to 8), and has a hypochlorite ion content of 30 mg / g or more and a maximum particle diameter of 5 μm or less as observed by SEM.SELECTED DRAWING: None

Description

[Technical field]

[0001] This relates to disinfectants and antiseptics that can be used in the air, water, soil, or any other environment to purify the environment after a disaster or to prevent the spread of infectious livestock diseases. [Background technology]

[0002] Hypochlorite hydrocalumite has the chemical formula 2[Ca2Al(OH)6 + ]·(ClO)2 - It is a compound represented by the formula "·nH2O (n = 0~8)". The hypochlorous acid type hydrocalumite of the present invention is a fine white powder and is expected to be used as a disinfectant for environmental purification after flood damage and for livestock infectious diseases such as avian influenza.

[0003] It may be dispersed as it is in powder form or granulated into granules, or it may be made into an aqueous slurry and sprayed, or it may be incorporated into paint and applied to floors, walls, ceilings, etc. Hypochlorite hydrocalumite combines the strong alkalinity derived from its raw material, slaked lime, with the strong bactericidal action of calcium hypochlorite or sodium hypochlorite.

[0004] Calcium hypochlorite is generally used as a disinfectant for pools and bathing facilities. Sodium hypochlorite is also often used as a household mold remover and dish bleach. Household bleach is generally handled as a liquid containing 5 to 15% sodium hypochlorite, but even in a sealed container it decomposes and the available chlorine decreases (see formula (1) below). To prevent this, a few percent of sodium hydroxide is added to increase the alkalinity, but it is still susceptible to the effects of temperature and light, and it is said that the available chlorine decreases significantly within a few weeks (see Non-Patent Document 1). Thus, hypochlorites are characterized by their fast-acting properties and are widely used as disinfectants, but they have many problems in terms of stability.

[0005] [ka]

[0006] On the other hand, slaked lime is used as an inexpensive alkaline agent to clean under floors after flooding, to prevent avian influenza, and as a disinfectant. The alkaline effect of slaked lime works by making the moisture in the soil strongly alkaline, so if there is no moisture, it will not be effective. Also, pathogenic bacteria and viruses are only inactivated when they come into contact with the alkali, so it is not effective against bacteria and viruses floating in the air.

[0007] In addition, since general hypochlorites volatilize and release hypochlorous acid, they can exert an inactivation effect even without contact with bacteria or viruses. However, these are highly soluble in water, and when sprayed in the environment, they are easily decomposed by organic matter and metals in the soil, or by ammonia contained in livestock waste, and lose their effectiveness (see formula (2) below).

[0008] [ka]

[0009] In contrast to these general hypochlorites, hypochlorite hydrocalumite, which is represented by the compound formula (3a) below, is a hypochlorite compound, but does not have ionic bonds like hypochlorites such as calcium hypochlorite and sodium hypochlorite, and the hypochlorite ions are fixed between the layers of the hydrocalumite layer structure in the form of intercalation, so there is very little elution of hypochlorite ions into water, making it possible to use it as a pigment. This characteristic makes it much more versatile and flexible in its usage.

[0010] A similar compound is hypochlorous acid hydrotalcite shown in the following formula (3b) (see Patent Document 1), in which the calcium ions in hydrocalumite are replaced with magnesium ions. Its composition suggests that it has similar properties to hypochlorite hydrocalumite, but because it is derived from magnesium, it is presumed to be less alkaline than calcium-derived hydrocalumite.The stability of the intercalated hypochlorite ion is thought to be similar to that of hypochlorite salts, so hydrocalumite with its strong alkalinity is expected to have an advantage in terms of storage stability.

[0011] [ka]

[0012] Generally, hydrocalumite is produced by starting with a soluble aluminum source such as sodium aluminate, as shown in the following formula (4) (see Patent Document 2), or by sintering calcium oxide or hydroxide and aluminum hydroxide at an ultra-high temperature of 1300°C or higher and rehydrating them, as shown in the following formula (5) (see Patent Document 3). However, all of these methods are undesirable in terms of raw material costs and production costs. In the former case, it is necessary to wash off the by-product salt, and in the latter case, a rapid exothermic hydration reaction occurs, which requires special care.

[0013] [ka]

[0014] [ka] [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Patent Publication No. 2022-074726 [Patent Document 2] Japanese Patent Application Publication No. 07-033430 [Patent Document 3] Japanese Patent Application Publication No. 07-033431 [Non-patent literature]

[0016] [Non-Patent Document 1] "The Science of Hypochlorous Acid" P24; by Satoshi Fukusaki: First edition published 2012.3.9 Summary of the Invention [Problem to be solved by the invention]

[0017] In view of the above circumstances, the present invention provides a disinfectant that has immediate and stable effectiveness in a wide range of usage environments, such as in the air, water, and soil. [Means for solving the problem]

[0018] The first aspect of the present invention is a method for producing hypochlorous acid type hydrocalumite, characterized in that the formation of the hypochlorous acid type hydrocalumite is carried out by mixing and reacting slaked lime, aluminum hydroxide having an activity ΔM of 0.3 or more, and calcium hypochlorite in water.

[0019] In the second aspect of the present invention, the hypochlorite type hydrocalumite in the first aspect is represented by the chemical formula: 2[Ca2Al(OH)6 + ]·(ClO)2 - This is a method for producing hypochlorite-type hydrocalumite, which is expressed as ·nH2O (n=0 to 8) and has a hypochlorite ion content of 30 mg / g or more.

[0020] A third aspect of the present invention is a method for producing hypochlorite-type hydrocalumite in the first and second aspects, characterized in that the maximum particle size of the hypochlorite-type hydrocalumite as determined by SEM observation is 5 μm or less.

[0021] A fourth aspect of the present invention is a compound having the formula: 2[Ca2Al(OH)6 + ]·(ClO)2- This is a hypochlorite type hydrocalumite characterized by having a hypochlorite ion content of 30 mg / g or more and a maximum particle size of 5 μm or less as determined by SEM observation, and expressed as nH2O (n = 0 to 8). Effect of the Invention

[0022] According to the present invention, there is provided a disinfectant that has immediate and stable effects in a wide range of usage environments, such as in the air, in water, and in soil. [Brief description of the drawings]

[0023] [Figure 1] 1 is an SEM image (magnification 5000 times) of the hypochlorous acid type hydrocalumite of the present invention according to Example 1; [Diagram 2] FIG. 2 is a process diagram of an SEM image (magnification: 5000 times) of hypochlorous acid type hydrocalumite according to Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] A specific embodiment of the present invention will be described. Note that the present invention is not limited to the following embodiment, and various modifications are possible without departing from the gist of the present invention.

[0025] [Method of manufacturing hypochlorous acid hydrocalumite] The manufacturing method of the present invention is characterized by the way in which hydrocalumite, which is the basic component, is synthesized. Hydrocalumite is a compound of "Ca2Al(OH)6 + ", so the preferred raw materials are calcium hydroxide (slaked lime) and aluminum hydroxide, which are inexpensively available. However, both have low solubility in water, and aluminum hydroxide is only weakly alkaline, so much so that it is almost neutral, so simply mixing the two in water or warm water will not cause a reaction to proceed, even after hours.

[0026] The method developed by the inventors is characterized by applying mechanical energy to aluminum hydroxide to distort its crystallinity (crystallinity distortion) and thereby expressing reaction activity (mechanochemical activation treatment), and is an excellent method that combines economy and reaction controllability. "Activity ΔM" is used as an index of reaction activity, and when aluminum hydroxide with an "activity ΔM" of 0.3 or more is used, the reaction is completed in one step as shown in the following formula (6), and no wasteful by-products are generated. With aluminum hydroxide with an "activity ΔM" of less than 0.3, the reaction shown in the following formula (6) is unlikely to occur, and the production of hydrocalumite does not proceed.

[0027] As a method for increasing the reaction activity (activity ΔM) of solid aluminum hydroxide in this way, a "mechanochemical activation treatment" is appropriate, and is carried out using a known technique (see, for example, JP-A Nos. 2002-274842 and 2002-274843).

[0028] [ka]

[0029] [Method for measuring "crystallinity distortion"] Generally, "crystalline distortion" can be observed by XRD, but the present inventors have proposed a method for easily and accurately evaluating it by measuring the weight of water removed by heating. With ordinary aluminum hydroxide, the dehydration reaction shown in formula (7) below begins to occur at around 230°C, but with mechanochemically activated aluminum hydroxide, dehydration begins to occur at temperatures below 100°C.

[0030] [ka]

[0031] [Calculation method of activity ΔM from "crystallinity distortion"] Therefore, by capturing the dehydration reaction of equation (7) through continuous observation of the dehydration state, it is possible to obtain the "crystallinity distortion" and the "evaporated water content % value," which is the proportion of water evaporated during the dehydration reaction, and calculate the "activity ΔM." For the measurement, a commercially available moisture meter that combines an electronic balance and a halogen heater can be used.

[0032] <Measurement conditions> Sample: Place 7.5±0.5g of powder (aluminum hydroxide) as evenly as possible on the weighing dish. Heating conditions: Heating temperature / 150℃ Heating time: 10 minutes (remarks) -The unit used is "evaporation moisture percentage value." To eliminate the effect of adhering moisture, subtract the 1 minute value from the 10 minute value. Use the subtracted value without the percentage. Example: 1.50%-0.65%=ΔM 0.85 This value is called "activity ΔM."

[0033] If the activity ΔM, which indicates the reaction activity of aluminum hydroxide, is 0.3 or less, the reaction activity of aluminum hydroxide is weak, so unreacted raw material components remain, resulting in a low content of hypochlorite ions in the product. In addition, the reaction rate is slowed down, which not only reduces productivity but also causes the particle size of the product to become coarse.

[0034] [Method for measuring hypochlorite ion content] <Sample preparation method> Weigh out 1.0g of powder containing hypochlorite hydrocalumite into a beaker, suspend it in 10ml of ion-exchanged water, and stir. Add 1.0g of sodium carbonate reagent and stir for 30 minutes to transfer the hypochlorite ions in the hydrocalumite to the liquid phase through ion exchange. This suspension is filtered, the solid phase is thoroughly washed with ion-exchanged water, and the amount of hypochlorous acid that has migrated to the liquid phase is quantified.

[0035] <Analysis method> Add 2.0 g of potassium iodide reagent to the entire filtrate while stirring, followed by 3 ml of acetic acid stock solution. The reaction shown in the following formula (8) occurs, and if hypochlorous acid is present, the solution will turn dark brown due to iodine at this point. Next, add 3 ml of starch solution. If iodine is produced, the solution will turn blue-purple due to the iodine-starch reaction. This solution is titrated with 0.1 mol / L sodium thiosulfate as shown in the following formula (9). The end point is when the solution becomes transparent due to the consumption of free elements in the reaction.

[0036] [ka]

[0037] [Hypochlorous acid type hydrocalumite] The "hypochlorite hydrocalumite" produced by the above manufacturing method has the chemical formula "2[Ca2Al(OH)6 + ]·(ClO)2 - It is expressed as "·nH2O (n = 0 to 8)" and is characterized by a hypochlorite ion content of 30 mg / g or more and a maximum particle size of 5 μm or less when observed with a 5,000x magnification SEM.

[0038] However, if the content of hypochlorite ions is less than 30 mg / g, the antifungal, bactericidal and disinfectant effects of the present invention cannot be sustained stably. Furthermore, if the maximum particle size is larger than 5 μm, it is not the standard size that is convenient for use as a pigment (dispersibility, fluidity, elongation), and the degree of freedom of processing in practical and applied aspects such as paint and film production may be significantly restricted. Here, as an alternative approach, there is a method of mechanically finely grinding the coarse particles, but it is considered that hypochlorite ions will dissipate due to heat and impact during grinding. Therefore, the present invention, which can obtain fine particles at the synthesis reaction stage, has an advantage. Due to these characteristics, the hypochlorous acid type hydrocalumite of the present invention has immediate effect regardless of the environment in which it is used, be it in the air, water, or soil, and exhibits its efficacy as a disinfectant stably. EXAMPLES

[0039] The present invention will be described in detail below with reference to examples. EXAMPLES

[0040] A 1L beaker was charged with 600g of water and 107g of hydrated lime (Furukawa Sangyo Co., Ltd., special powder form) and stirred to prepare a hydrated lime slurry. 69g of calcium hypochlorite (Nippon Soda Co., Ltd., "High-grade bleaching powder", granular form) was then added and dissolved while stirring. To this was added 75 g of aluminum hydroxide (raw powder: Sumitomo Chemical Co., Ltd., C-31 origin, powder form) with an activity adjusted by mechanochemical activation treatment of "activity ΔM" 0.74 and an average particle size of 5.5 μm to produce a mixture slurry. After stirring for 15 minutes, this was transferred to an airtight container and kept at 70°C for 30 hours without stirring in a shelf-type warmer.

[0041] The obtained slurry was subjected to suction filtration, and the filter cake was washed with 1 L of water and dried at 70° C. for 15 hours to obtain a white powder. The content of hypochlorite ions in this white powder was 90 mg / g, and according to the SEM image at 5000 times magnification shown in Figure 1, the particles were basically plate-like particles with sizes of 1 to 3 μm. EXAMPLES

[0042] The same procedure as in Example 1 was carried out except that the activity of aluminum hydroxide was set to ΔM 0.51. The content of hypochlorite ions in the obtained powder was 59 mg / g, and SEM observation at 5000x magnification showed that the particles were basically plate-like particles of 1 to 3 μm. EXAMPLES

[0043] The same procedure as in Example 1 was carried out, except that the activity of the aluminum hydroxide was set to ΔM 0.35. The content of hypochlorite ions in the obtained powder was 35 mg / g, and according to SEM observation at a magnification of 5000 times, the particles were basically plate-like particles of 1 to 5 μm.

[0044] Comparative Example 1 The same procedure as in Example 1 was carried out except that aluminum hydroxide C-31 was used as it was. The activity of the aluminum hydroxide at this time was ΔM0.00, and the average particle size was 50 μm. The content of hypochlorite ions contained in the obtained powder was 12 mg / g, and according to the SEM image at a magnification of 5000 times shown in Figure 2, the shape of the particles was 10 μm or more and was a non-uniform, irregular, coarse particle.

[0045] Comparative Example 2 The same procedure as in Example 1 was carried out, except that aluminum hydroxide C-305 manufactured by Sumitomo Chemical Co., Ltd., with an average particle size of 5 μm, was used. The activity of the aluminum hydroxide at this time was ΔM0.00. The content of hypochlorite ions contained in the obtained powder was 24 mg / g, and according to SEM observation at a magnification of 5000 times, the particle shape was 5 μm or more and was a non-uniform, irregular, coarse particle.

[0046] Comparative Example 3 The aluminum source was changed to alumina cement (No. 1, manufactured by Denka Co., Ltd.). Based on the composition, 60 g of alumina cement, 41 g of slaked lime, and 48 g of calcium hypochlorite were mixed and stirred, and heated under the same conditions as in the example. The obtained powder was gray-brown in color, and the content of hypochlorite ions was 0 mg / g.

[0047] [Characteristics evaluation] <Culture Test A> The powders obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were molded into tablets having a diameter of 10 mm and a thickness of 3 mm using a tablet press. The samples containing the target bacteria were prepared by scrubbing bacteria attached to the bathroom sink in the applicant's office with a cotton swab and suspending them in a small amount of purified water to prepare Liquid A, and by suspending commercially available black koji, which represents mold, in a small amount of purified water to prepare Liquid B. The medium used was "Compact Dry TC / diameter 50 mm" manufactured by Nissui Pharmaceutical Co., Ltd., for general viable cell count measurement.

[0048] Test samples were prepared by placing the tablet of each Example and Comparative Example in the center, and 1 ml of each of the A liquid sample and the B liquid sample was dropped onto the prepared medium, which was then cultured at 35°C for 48 hours, and the distance at which the proliferation of bacteria or mold was prevented was measured. The results are shown in Table 1 below. Table 1 shows that the antibacterial effect is proportional to the hypochlorite ion content.

[0049] [Table 1]

[0050] <Ammonia resistance> First, 1.0 g of the product of Example 2 was weighed into a beaker containing 20 ml of purified water, 5 ml of 10% ammonia water was added, and the mixture was stirred for 60 minutes. This was filtered, and the chloride ions dissolved in the filtrate were titrated with an aqueous silver nitrate solution using potassium chromate as an indicator according to the Mohr method. The measurements showed that 15% of the hypochlorite ions were lost due to ammonia.

[0051] Next, 1.0 g of 5% aqueous solution of highly bleached powder was weighed out into a beaker containing 20 ml of purified water, and 5 ml of 10% aqueous ammonia was added and stirred for 60 minutes. The residual hypochlorite ions in this aqueous solution were quantified by potassium iodide-sodium thiosulfate titration method. The measurements showed that 33% of the hypochlorite ions were lost due to ammonia. These two experiments demonstrate that the hypochlorite type hydrocalumite of the present invention has a certain degree of ammonia resistance.

[0052] <Soil resistance> First, 1.0 g of the product of Example 2 was weighed into a beaker containing 20 ml of purified water, and 2.0 g of soil collected from the applicant's flowerbed was added and stirred for 60 minutes. This was filtered, and the chloride ions dissolved in the filtrate were titrated according to the Mohr method. The measurements showed that 8.4% of the hypochlorite ions were lost by the soil.

[0053] Next, 1.0 g of a 5% aqueous solution of highly bleached powder was weighed out into a beaker containing 20 ml of purified water, and 2.0 g of soil collected from our flower bed was added and stirred for 60 minutes. The residual hypochlorite ion in this aqueous solution was quantified by potassium iodide-sodium thiosulfate titration method. Measurements showed that 97% of the hypochlorite ions were lost by the soil. Two experiments demonstrate that the hypochlorite type hydrocalumite of the present invention has remarkable soil resistance.

[0054] <Paper coating and mold resistance test> - Sample preparation The hypochlorite type hydrocalumite of Example 1 and light calcium carbonate (manufactured by New Lime Co., Ltd.) were mixed in the ratio shown in Table 2, and 12% of SB latex was added to prepare a water-based paint with a solid content of 48%. This is applied using an applicator with a clearance of 25 μm, with a basis weight of 300 g / m 2 After coating on thick paper, it was dried and cut into 30 mm squares to prepare test pieces.

[0055] <Mold resistance test> ·Complies with JIS Z2911:2000 Mold types: Aspergillus niger / Penicillium cinnamonium / Rhizopus oryzae / Cladosporium cladosporioidus / Chaetomium globosum · Culture medium Standard fungal agar medium ·Temperature 30℃, humidity 90%

[0056] The test results are shown in Table 2. The test results show that hypochlorous acid type hydrocalumite has mold resistance properties.

[0057] [Table 2]

Claims

1. A method for producing hypochlorous acid type hydrocalumite, comprising the steps of: The method for producing hypochlorite-type hydrocalumite is characterized in that the formation of the hypochlorite-type hydrocalumite is carried out by mixing and reacting slaked lime, aluminum hydroxide having an activity ΔM of 0.3 or more, and calcium hypochlorite in water.

2. The hypochlorous acid type hydrocalumite is Chemical formula: 2[Ca 2 Al(OH) 6 + ] (ClO) 2 - ・nH ２ O (n = 0 to 8), 2. The method for producing hypochlorite type hydrocalumite according to claim 1, characterized in that the content of hypochlorite ions is 30 mg / g or more.

3. 3. The method for producing hypochlorite-type hydrocalumite according to claim 1, wherein the maximum particle size of the hypochlorite-type hydrocalumite as determined by SEM observation is 5 μm or less.

4. Chemical formula: 2[Ca 2 Al(OH) 6 + ] (ClO) 2 - ・nH ２ O (n = 0 to 8), The content of hypochlorite ions is 30 mg / g or more, The maximum particle size observed by SEM is 5 μm or less. The present invention relates to a hypochlorous acid type hydrocalumite.

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