KR20120103321A - Manufacturing method of inorganic antibiotics - Google Patents

Abstract

PURPOSE: A method for manufacturing inorganic antibacterial agent is provided to enhance adsorption and substitution rate of antibacterial metal ions and to protect water quality environment. CONSTITUTION: A method for manufacturing inorganic antibacterial agent comprises: a step of dissolving aluminum sulfate in water to prepare an aluminum sulfate solution; a step of mixing the calcium salt with water to prepare slurry; a step of mixing the aluminum sulfate solution and slurry to prepare a mixture solution; a step of heating the mixture solution at 30-150 Deg. C.; and a step of adsorbing or substituting an antibacterial metal ion to calcium aluminum sulphate. The antibacterial includes nickel, cobalt, zinc, chrome, cadmium, lead, arsenic, or copper.

Description

Manufacturing method of Inorganic antibiotics

The present invention relates to a method for preparing an inorganic antibacterial agent in which an antibacterial metal ion capable of providing antibacterial activity to calcium aluminum sulfate is adsorbed or substituted.

Antimicrobial means inhibiting and preventing microbial propagation, and a substance having such an effect is called an antimicrobial substance or an antimicrobial agent. In addition, sterilization (sterilization) means essentially killing microorganisms. Fungicides are known to have excellent activity in removing all propagated microorganisms but have no lasting effect, while antimicrobial agents are known to exhibit relatively lasting effects. Therefore, a product containing an antimicrobial agent as an additive can be expected to prevent the growth of microorganisms to prevent diseases caused by microbial infection.

Antibacterial agents added to prevent bacterial propagation can be roughly divided into organic (including organic metals) and inorganic.

Organic antibacterial agent mainly utilizes the effect of dissolution of the drug, and acts more like antibacterial to prevent the formation of a colony of bacteria than sterilization. The biggest advantage of using organic antimicrobial agent is that the exposure to the surface of the object to be sterilized is rapidly progressed, which prevents the immediate growth of bacteria and is relatively inexpensive. On the other hand, not only is the durability of the product weak due to rapid dissolution due to the rapid migration of organic antimicrobial agents, but it is impossible to apply due to the thermal decomposition of organic antimicrobial agents when high temperature work is required during the manufacturing process of the product. There is a problem, and in particular, there is a disadvantage that can not be used where the toxicity problem due to the fluidity and solubility of organic matter.

Inorganic antibacterial agent is a product made by substituting silver, zinc, copper, etc. which are metal ions that have antimicrobial action on inorganic materials such as zeolite, calcium phosphate, zirconium phosphate, silica gel, etc. It is becoming. Inorganic antimicrobial agents have a temporary antimicrobial activity, but they are higher in human safety, no resistant bacteria, and antimicrobial duration is almost semi-permanent. Currently, these inorganic antimicrobial agents are mainly in the form of zeolite, calcium phosphate, and zirconium phosphate, and among them, zeolite inorganic antibacterial agents have the highest market share. Calcium phosphate-based antimicrobial agents have the disadvantage of lowering antimicrobial activity than zeolite-based due to lower concentration of metal ions compared to zeolite-based inorganic antimicrobials. Has a high disadvantage.

As described above, zeolite-based inorganic antimicrobials have several advantages, such as no discoloration problem, higher antimicrobial activity, and lower particle hardness than other antimicrobial agents.However, the metal ions substituted in the zeolite are immersed in water when they are immersed in water. As it is eluted by the metal ion that provides antimicrobial activity, it is very likely to contaminate the water environment, and the substitution rate of metal ion is slightly higher than that of calcium phosphate-based antimicrobial agents. It is true.

Thus, in order to overcome the disadvantages of the conventional inorganic antimicrobial agents of the inorganic antimicrobial agent that has a high substitution rate with metal ions and does not dissolve in water under water conditions to provide high antimicrobial activity while minimizing economical and environmental pollution. A lot of research is going on to develop.

Korean Patent Laid-Open Publication No. 1996-0029493 discloses an insoluble silver phosphate inorganic antimicrobial agent which simultaneously prepares a carrier and supports silver ions by adding and mixing phosphoric acid and an aqueous solution of silver nitrate, titanium dioxide and colloidal silica sequentially. A manufacturing method is proposed. This is because the preparation of the carrier and the support of the silver ions are made at the same time, it is easy to control the content of the silver ions, and can provide stable and continuous bactericidal and antimicrobial properties, but silver (Ag) included as an inorganic antibacterial agent is very expensive. Therefore, there is a disadvantage that it is difficult to apply to various fields for providing antibacterial activity.

Korean Patent Laid-Open Publication No. 2002-0017536 proposes a method of maximizing efficacy as an inorganic antimicrobial agent by obtaining titanium oxide from natural minerals. It can decompose organic matter by photocatalyst by titanium oxide and can provide antimicrobial effect, but its effect is very insignificant and used in very limited fields, especially photocatalyst obtained by the proposed patent process Because of the large surface area, the effect of the photocatalyst is very low.

Korean Patent Laid-Open Publication No. 2002-0096759 proposes an antimicrobial agent manufacturing method using silver (Ag) and bromine compounds. The final compound of the proposed invention is in the form of silver bromide (AgBr) is thought to be able to provide antimicrobial activity, but bromine not only adversely affects the human body, but silver (Ag) is very expensive to provide a variety of antimicrobial activity It is difficult to apply to the field.

Accordingly, the present inventors have tried to prepare an inorganic antimicrobial agent having excellent antibacterial ability while overcoming the problems of environmental pollution and harmful effects of the conventional inorganic antimicrobial agent, and thus prepared calcium aluminum sulfate through hydrothermal synthesis from aluminum sulfate and calcium salt, and then Adsorption or substitution of the metal ions was found to be excellent in the antibacterial activity, and to obtain an inorganic antibacterial agent with little leaching of the adsorbed or substituted antibacterial metal ions to complete the present invention. Therefore, an object of the present invention is to provide a method for preparing a new inorganic antibacterial agent.

The present invention

Dissolving aluminum sulfate in water to prepare an aluminum sulfate solution;

Mixing the calcium salt with water to prepare a slurry;

Preparing a mixed solution by mixing the aluminum sulfate solution and the slurry;

Hydrothermally synthesizing calcium aluminum sulfate by heating the mixed solution to 30 to 150 ° C; And

Adsorbing or replacing antimicrobial metal ions on the calcium aluminum sulfate;

Characterized in that the manufacturing method of the inorganic antibacterial agent comprising a.

According to the preparation method of the inorganic antimicrobial agent of the present invention, the antimicrobial metal ion can be obtained by increasing the amount of antimicrobial metal ion adsorbed or substituted with calcium aluminum sulfate, and the antimicrobial metal ion adsorbed or substituted with the inorganic antimicrobial agent is hardly eluted. Therefore, it is possible to prevent damage caused by physical contact as well as protecting the water environment. In addition, such an inorganic antimicrobial agent can be prepared from a simple process and relatively inexpensive raw materials, and thus can be usefully applied to textiles, medicines, cosmetics, home appliances, and construction fields where antimicrobial substances are required.

1 is a photograph of the inorganic antimicrobial agent of the present invention in which nickel ions (a), copper ions (b), cobalt ions (c), and zinc ions (d) are respectively adsorbed or substituted on calcium aluminum sulfate. )

Hereinafter, the present invention will be described in more detail.

The present invention relates to a method for preparing an inorganic antimicrobial agent by mixing an aluminum sulfate solution and a calcium salt slurry and then adsorbing or replacing antibacterial metal ions with hydrothermally synthesized calcium aluminum sulfate by heating to 30 to 150 ° C. Japanese Patent Laid-Open No. 6-271411 proposes a method for preparing antimicrobial and flavoring agents by adding an antimicrobial metal compound to etrinite, but does not provide specific means for synthesizing ethrinite. In addition, the reactants and preparation methods used in the manufacturing process are completely different from the present invention.

First, aluminum sulfate is dissolved in water to prepare an aluminum sulfate solution. The aluminum sulfate may be used in any of a powder type for reagents and an aqueous type used as an inorganic coagulant. In addition, it is preferable to use distilled water having good purity, but ground water, industrial water, etc. may be used as long as it does not contain environmentally harmful substances such as heavy metals. Although the aluminum sulfate concentration in the said aluminum sulfate solution is not specifically limited, 1.0-20 weight% is preferable. When the aluminum sulfate concentration is low, the stirring is smooth as the solid content is low, but the yield of calcium aluminum sulfate produced through hydrothermal synthesis with the calcium salt may be lowered. When the concentration exceeds 20% by weight, the calcium aluminum sulfate Although it is possible to increase the production rate, there is a problem that it is difficult to manufacture in a uniform state as the viscosity increases.

Next, the calcium salt is mixed with water to prepare a slurry. The calcium salt may be used at least one selected from calcium oxide (CaO), calcium hydroxide (Ca (OH) ₂ ) and calcium carbonate (CaCO ₃ ). Since the calcium salt is insoluble, it is highly desirable to maintain fluidity including water rather than powder for a normal reaction with aluminum sulfate. The calcium salt is used in a slurry in which water is mixed with water.

Next, the step of preparing a mixed solution by mixing the aluminum sulfate solution and the slurry prepared above. The molar ratio of aluminum sulfate and calcium salt in the mixed solution is preferably mixed so that 1: 4 to 1: 8, more preferably 1: 4.5 to 7.5, most preferably 1: 5 to 7 good. When the calcium salt is too small compared to aluminum sulfate, the excess aluminum sulfate remaining after the reaction may be contained in the inorganic antimicrobial agent, which is the final product. The aluminum sulfate is acidic in aqueous solution, and the antibacterial metal ions adsorbed or substituted with calcium aluminum sulfate are eluted. There may be a problem. On the contrary, when the calcium salt is supplied in an excessive amount, the antibacterial activity may be lowered by lowering the adsorption amount of the antibacterial metal ions to calcium aluminum sulfate by the unreacted calcium salt.

Next, a step of hydrothermally synthesizing calcium aluminum sulfate by heating the mixed solution to 30 ~ 150 ℃. One of the features of the present invention is to provide calcium aluminum sulfate by hydrothermal synthesis, wherein the heating temperature is 30 ~ 150 ℃, preferably the heating temperature is 40 ~ 115 ℃, more preferably 55 ~ 95 ℃, Most preferably, 65-80 degreeC is good. If the heating temperature is lower than 30 ℃, the yield of calcium aluminum sulfate is low and there is a high possibility that the unreacted substances are independently present, and if the heating temperature is higher than 150 ℃, calcium aluminum sulfate for preparing the inorganic antibacterial agent can be perfectly provided. Although it has advantages, it requires a lot of equipment and maintenance costs due to the need for an autoclave that can withstand high temperatures and pressures, and not only can increase the risk of workers during the reaction process, but also increase energy consumption. Because of this problem of falling, it is preferable to heat the temperature range proposed above. Calcium aluminum sulfate prepared by hydrothermal synthesis is prepared as a white precipitate.

Next, the inorganic antibacterial agent of the present invention may be obtained by adsorbing or replacing the antibacterial metal ions with calcium aluminum sulfate. Antibacterial metal ions that can be adsorbed or substituted include nickel (Ni), cobalt (Co), zinc (Zn), chromium (Cr), cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As) and copper ( A salt containing at least one selected from Cu) may be used in a form in which water is dissolved in water. Examples of the metal salt of nickel sulfate hexahydrate _{(NiSO 4? 6H 2 O)} , cobalt nitrate hexahydrate _{(Co (NO 3) 2?} 6H 2 O), zinc chloride (ZnCl _2), potassium dichromate (K ₂ Cr ₂ O ₇ ), cadmium nitrate (Cd (NO ₃ ) ₂ ), lead nitrate (Pb (NO ₃ ) ₂ ), mercury nitrate (Hg (NO ₃ ) ₂ ), arsenic chloride (AsCl ₃ ), copper sulfate pentahydrate (CuSO ₄ ? 5H ₂ O) and the like, but is not limited thereto. After ionizing the antimicrobial metal, calcium aluminum sulfate is added thereto, followed by stirring so that the antimicrobial metal ion can be uniformly adsorbed or substituted. In this case, it is preferable to use the powdered calcium aluminum sulfate, which is obtained by drying and pulverizing to increase the surface area and to easily adsorb or replace the antimicrobial metal. At this time, the amount of the antimicrobial metal ions that are adsorbed and substituted with calcium aluminum sulfate may vary depending on the type of metal salt used to provide the antimicrobial activity. Accordingly, in order to maximize the antimicrobial activity, it is desirable to adsorb and replace the maximum amount of antibacterial metal ions possible. To this end, it is preferable to supply and dissolve excess antimicrobial metal salts more than the maximum adsorption and substitution amount of the antimicrobial metal ions, and the antimicrobial metal ion content of the inorganic antimicrobial agent prepared by the present invention is up to 36% by weight.

Excess antibacterial metal ions that are not adsorbed or substituted in the adsorption and substitution step can be removed by filtering and washing the inorganic antibacterial agent as a precipitate. There is no particular restriction as to the cleaning liquid, and water can be used by using impurities-free water. In addition, the inorganic antimicrobial agent recovered through filtration and washing is preferably processed into a powder form that is convenient to use through drying and grinding.

The inorganic antimicrobial agent prepared according to the present invention can be manufactured at low cost because the raw material is low in price, and even if deposited in water, the amount of the adsorbed and substituted antimicrobial metal ions is minimal or very low, thus damaging the water environment or the human body. Strong antibacterial activity can be achieved without giving. Therefore, these environmentally friendly inorganic antimicrobial agents are expected to be widely applicable to textiles, medicine, cosmetics, home appliances, and construction fields.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

[ Example ]

Example 1

Considering the aluminum sulfate 6-8 hydrate of Samjeon Pure Chemical Co., Ltd. as aluminum sulfate hexahydrate, the amount corresponding to 0.1 mol is weighed into 5 L beakers of 2 L, and 1 L of distilled water is added, followed by a stirrer. The aluminum sulfate solution was prepared by completely dissolving aluminum sulfate. Into another 500 mL beaker was added 0.4, 0.5, 0.6, 0.7, 0.8 mol of calcium hydroxide and 250 mL of distilled water, respectively, and then a slurry was prepared by stirring.

The slurry was added to the aluminum sulfate solution to prepare a mixed solution, and the mixture was heated at 55 ° C. for 3 hours while stirring with a stirrer to hydrothermally synthesize calcium aluminum sulfate. Thereafter, after cooling the mixed solution, the precipitate was filtered and washed five times, and then dried and pulverized in a dry oven to obtain calcium aluminum sulfate powder.

Nickel sulfate hexahydrate (NiSO ₄ ˜6H ₂ O) and cobalt nitrate hexahydrate (Co (NO ₃ ) ₂ ˜6H in a 100 mL beaker to absorb and replace the antibacterial metal ions to the calcium aluminum sulfate powder prepared above ₂ O), zinc chloride (ZnCl ₂ ), potassium dichromate (K ₂ Cr ₂ O ₇ ), cadmium nitrate (Cd (NO ₃ ) ₂ ), lead nitrate (Pb (NO ₃ ) ₂ ), mercury nitrate (Hg (NO _{3) 2)} chloride, arsenic (AsCl ₃₎ and copper sulfate pentahydrate (CuSO _4? 5H ₂ O) respectively to measurement by 5 g, and supplied to each beaker with distilled water to 100 mL, stirring with a magnetic stirrer (magnetic stirrer) To dissolve the antibacterial metal ions. Next, 2.5 g of calcium aluminum sulfate powder prepared above was supplied to the solution in which the antimicrobial metal salt was dissolved, and stirred for 1 hour to adsorb and substitute metal ions capable of providing antimicrobial activity. Thereafter, the slurry containing water was filtered, completely dried in a dry oven at 100 ° C., and then ground to recover a powdery inorganic antimicrobial agent in which antibacterial metal ions were adsorbed and substituted with calcium aluminum sulfate.

In order to confirm the adsorption and substitution amount of the antimicrobial metal ions of the prepared inorganic antimicrobial agent, 0.1 g of the inorganic antimicrobial agent was accurately measured to the fourth decimal place, and then introduced into a beaker, followed by heating in the presence of nitric acid to dissolve the inorganic antimicrobial agent. Thereafter, the solution in which the inorganic antimicrobial agent was dissolved was cooled, diluted using a 100 mL volumetric flask and analyzed by ICP / ES (Jobin Yvon Ultima-C Inductively Coupled Plasma-Atomic Emission Spectrometer). The analysis results are shown in Table 1 below.

Comparative Example 1

The same procedure as in Example 1 was carried out except that 4A-zeolite manufactured by ZeoBuilder Co., Ltd. was used instead of calcium aluminum sulfate.

division Molar ratio
Al ₂ (SO ₄ ) ₃ : Ca (OH) ₂ Adsorption and substitution rate of antibacterial metal ions (% by weight) Ni Co Zn Cr CD Pb Hg As Cu Example 1 1: 4 19.4 17.9 24.3 9.82 14.8 21.1 4.46 7.62 29.4 1: 5 24.2 20.2 26.7 14.4 19.6 24.7 9.82 12.5 33.8 1: 6 26.5 22.6 28.4 19.4 23.1 28.4 18.0 21.1 35.4 1: 7 23.4 19.9 27.2 15.1 21.4 25.4 10.4 14.4 31.9 1: 8 17.6 16.2 23.9 10.3 15.3 20.9 6.33 8.86 30.2 Comparative Example 1 Zeolite (4A) 0.86 0.74 0.33 0.46 0.58 1.18 0.22 0.23 0.81

As shown in Table 1, in the case of zeolite 4A used as a conventional inorganic antimicrobial agent of Comparative Example 1, while the adsorption and substitution rate of metal ions that can provide antimicrobial properties are in the range of about 0.2 to 1.2% by weight, The maximum content of the antimicrobial metal ions adsorbed and substituted in the inorganic antimicrobial agent prepared in Example 1 was in the range of 18 to 36% by weight, and the adsorption and substitution rate of the antimicrobial metal ions was best when the molar ratio of aluminum sulfate and calcium hydroxide was 1: 6. It can be seen that excellent.

Example 2

1 g of the inorganic antimicrobial agent prepared in Example 1 was accurately measured to 4 decimal places, aliquoted into 100 mL of a beaker, about 50 mL of distilled water was added, and then stirred for 2 hours using a magnetic rod. The sample was then diluted with a 100 mL volumetric flask and analyzed by ICP / ES to determine the amount of antibacterial metal ions eluted in water. The measurement results are shown in Table 2 below.

division Molar ratio
Al ₂ (SO ₄ ) ₃ :
Ca (OH) ₂ Elution amount of antibacterial metal ion Ni
(ppm) Co
(ppm) Zn
(ppm) Cr
(ppm) CD
(ppm) Pb
(ppm) Hg
(ppb) As
(ppb) Cu
(ppm) Example 2 1: 4 0.018 N.D. 0.14 0.080 0.062 N.D. 8.7 16.8 0.014 1: 5 N.D. N.D. 0.088 0.045 0.048 N.D. N.D. 12.4 N.D. 1: 6 N.D. N.D. 0.082 0.012 0.044 N.D. N.D. 8.9 N.D. 1: 7 N.D. N.D. 0.094 0.036 0.059 N.D. N.D. 11.8 N.D. 1: 8 0.020 N.D. 0.22 0.066 0.088 N.D. 4.4 14.7 0.026 ND: non-detectable
Detection limits of Ni, Co, Pb and Cu are 0.01 ppm and Hg is 1 ppb.

As shown in Table 2, the inorganic antimicrobial agent of the present invention does not adversely affect the water environment or the human body because the antimicrobial metal is not detected or eluted at a very small concentration when eluted for 2 hours under water conditions. have.

Example 3

In order to confirm the antimicrobial activity of the inorganic antimicrobial agent, powders in which cobalt (Co), copper (Cu), nickel (Ni) and zinc (Zn) were respectively adsorbed and substituted on the calcium aluminum sulfate prepared in Example 1 were selected as inorganic antimicrobial agents. (CAS-Co, CAS-Cu, CAS-Ni, CAS-Zn). 10 g of alpha-half gypsum was weighed and placed in a paper cup, and then 0.025 g of the selected inorganic antimicrobial agent was accurately measured and added, mixed uniformly, and 4 mL of distilled water was supplied to prepare a molded body by hydroplasting gypsum. Thereafter, the molded body was sterilized in a dry oven at 130 ° C. for 2 hours, and a sample for antimicrobial experiment was prepared.

The target microorganisms for the antimicrobial experiments were used Paracoccus microorganisms purchased from the Korea Microbial Conservation Center, and prepared 100 microorganisms in the concentration shown in Table 3 and then inject 100 mL of the sterilized media solution in the autoclave Then, by incubating for 20 days in an incubator at 30 ℃ prepared a microbial sample solution for the antimicrobial experiment.

In order to confirm the antimicrobial activity of the inorganic antimicrobial agent of the present invention, a sterilized medium solution was used, and all the equipment necessary for the culture were sterilized in order to prevent contamination by various bacteria during the culture process.

The mechanism for identifying the antimicrobial activity of the inorganic antimicrobial agent produces sulfuric acid when the microorganisms of paracoccus versutus breed, thus reducing red by the indicator containing phenol red when the pH of the solution is lowered. To see if it changes from color to yellow.

Therefore, for the antimicrobial experiment, put the samples for the antimicrobial experiment in a sterilized glass container, each of the microorganisms of the paracoccus cultured in the container consisting of only a glass container without containing any inorganic antimicrobial agent as a blank (blank) Supply 25 mL of the included medium solution, immediately close the lid with aluminum foil to prevent the influx of bacteria, and check the degree of discoloration of the phenol red indicator for 30 days in an incubator at 30 ℃ for antibacterial activity. It was confirmed, and the results are shown in Table 4.

division weapon
Antibacterial agents Sampling date in days 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 room
city
Yes
3 CAS-Co ● ● ● ● ● ● ● ● ● ● ● ● ◎ ◎ ◎ CAS-Cu ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● CAS-Ni ● ● ● ● ● ● ● ● ● ● ● ● ● ● ◎ CAS-Zn ● ● ● ● ● ● ● ◎ ◎ ◎ ◎ ◎ ○ ○ ○ Blank ● □ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ●: Dark red, ◎: Dark-light red, ○: Light red
■: dark yellow, △: dark-light yellow, □: pale yellow

As shown in Table 4, in the case of a blank sample containing no inorganic antimicrobial agent prepared by the present invention and only a medium solution containing microorganisms, the microorganisms of Paracoccus bustus immediately grow to produce sulfuric acid. At the same time, the pH of the phenol red indicator changes to yellow within several days, and when the inorganic antimicrobial agent is not included, it can be confirmed that the microorganism is rapidly multiplied, whereas the inorganic antimicrobial agent prepared according to the present invention is added to the medium solution. It has been confirmed that the antibacterial activity can be provided as the discoloration does not occur until 20 days have elapsed, and the calcium aluminum sulfate inorganic antibacterial agent in which copper ions are adsorbed and substituted among the inorganic antimicrobial agents of the present embodiment has the best antibacterial effect. I could confirm it. In addition, it was confirmed that the amount can be provided as a versatile, environmentally friendly inorganic antimicrobial agent if the amount added according to the type of calcium aluminum sulfate inorganic antimicrobial agent through the examples.

As a result, the inorganic antimicrobial agent prepared by the present invention can exhibit excellent antimicrobial activity due to the high content of the adsorbed or substituted antimicrobial metal ions, and the contained antimicrobial metal does not elute back into water and thus does not cause human and environmental pollution problems. It was confirmed that the zeolite inorganic antimicrobial agent used as an inorganic antimicrobial agent could be replaced.

Claims (6)

Dissolving aluminum sulfate in water to prepare an aluminum sulfate solution;
Mixing the calcium salt with water to prepare a slurry;
Preparing a mixed solution by mixing the aluminum sulfate solution and the slurry;
Hydrothermally synthesizing calcium aluminum sulfate by heating the mixed solution to 30 to 150 ° C; And
Adsorbing or replacing antimicrobial metal ions on the calcium aluminum sulfate;
Method of preparing an inorganic antimicrobial agent.
The method according to claim 1, wherein the calcium salt is at least one selected from calcium oxide, calcium hydroxide and calcium carbonate.
The method according to claim 1, wherein the molar ratio of aluminum sulfate and calcium salt in the mixed solution is 1: 4 to 8.
The method of claim 1, wherein the antimicrobial metal is at least one selected from nickel, cobalt, zinc, chromium, cadmium, lead, mercury, arsenic, and copper.
The method of claim 1, wherein the content of the antimicrobial metal ions is 36% by weight or less method for producing an inorganic antimicrobial agent.
An inorganic antimicrobial agent prepared by the method of any one of claims 1 to 5.

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