Inorganic Bacteriostatic Slurry

Abstract

To provide an inorganic bacteriostatic slurry that has a long lasting effect.SOLUTION: An inorganic bacteriostatic slurry has porous silica doped with a bacteriostatic metal, the porous silica suspended in a dispersant. For example, the bacteriostatic metal is copper, zirconium, cobalt.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an inorganic bacteriostatic slurry that has excellent durability of effect. [Background technology]

[0002] It has long been known that metals such as copper, silver, and zinc exert bacteriostatic effects in the form of ions, and inorganic bacteriostatic slurries, which are prepared by adsorbing these metal ions onto carriers such as silica gel or zeolite and suspending them in a dispersion medium such as water, are used as materials for imparting bacteriostatic properties to everyday items such as textiles, leather products, building materials, wood, paints, adhesives, plastics, films, ceramics, paper, pulp, metal processing oils, water treatment agents, cosmetics, stationery, toys, containers, caps, dispensers, and spouts (e.g., Non-Patent Document 1). However, such inorganic bacteriostatic slurries exert their bacteriostatic effects by desorbing the bacteriostatic metal ions adsorbed onto the carrier, and therefore, as the amount of bacteriostatic metal ions adsorbed onto the carrier gradually decreases, the bacteriostatic effect also gradually decreases. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Yoshinobu Matsumura, Antibacterial properties of silver ions and copper ions, Chemistry and Education, Vol. 53, No. 5 (2005), pp. 288-291 Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, an object of the present invention is to provide an inorganic bacteriostatic slurry that has excellent durability of effect. [Means for solving the problem]

[0005] The present inventors have been actively engaged in the research and development of porous silica doped with various metals, and as one of their results, they reported in JP 2020-15640 A that porous silica doped with manganese, copper, and iron exhibits excellent deodorizing effects against sulfur-containing odors. Here, "metal-doped porous silica" refers to porous silica in which a metal is chemically bonded and incorporated into the inorganic network consisting of siloxane bonds that constitutes the porous silica. As a result of further research and development of metal-doped porous silica, the present inventors discovered that a slurry obtained by suspending porous silica doped with a bacteriostatic metal in a dispersion medium has excellent durability of the bacteriostatic effect.

[0006] The inorganic slurry for bacteriostasis of the present invention, which has been made based on the above findings, is as described in claim 1, At least one selected from copper, zirconium, cobalt, silver, and zinc bacteriostatic metal and aluminum (In the above, the bacteriostatic metal-doped porous silica means porous silica in which the bacteriostatic metal is incorporated by chemical bonding into the inorganic network consisting of siloxane bonds that constitutes the porous silica.) 。 Ma and claims 2 The inorganic slurry for bacteriostatic purposes described in claim 1 The inorganic bacteriostatic slurry described is further doped with at least one metal selected from manganese and iron. Also, claims 3 The inorganic slurry for bacteriostatic purposes described in claim 1 or 2 In the described bacteriostatic inorganic slurry, the dispersion medium is water. The article of the present invention also includes the following: 4 As described above, claims 1 to 3 The present invention includes an inorganic slurry for bacteriostasis according to any one of the above. The present invention also provides the following claims: 5 As stated, At least one selected from copper, zirconium, cobalt, silver, and zinc bacteriostatic metal and aluminumand use of a slurry obtained by suspending porous silica doped with a bacteriostatic metal in a dispersion medium for bacteriostasis (in the above, the bacteriostatic metal-doped porous silica means porous silica in which the bacteriostatic metal is incorporated by chemical bonding into the inorganic network consisting of siloxane bonds that constitutes the porous silica). [Effects of the Invention]

[0007] According to the present invention, an inorganic bacteriostatic slurry having excellent durability of effect can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0008] The inorganic bacteriostatic slurry of the present invention is prepared by suspending porous silica doped with a bacteriostatic metal in a dispersion medium.

[0009] Examples of bacteriostatic metals that can be used in the present invention include copper, zirconium, and cobalt, which are metals that exhibit bacteriostatic effects in the form of ions and are known to be capable of being doped into porous silica. The bacteriostatic metals may be used alone or in combination of two or more.

[0010] The content of the bacteriostatic metal in the bacteriostatic metal-doped porous silica is, for example, 0.01 to 10 wt%, preferably 0.1 to 5 wt%. If the content of the bacteriostatic metal in the bacteriostatic metal-doped porous silica is less than 0.01 wt%, a sufficient bacteriostatic effect may not be obtained, while porous silica doped with a bacteriostatic metal in an amount exceeding 10 wt% may be difficult to produce.

[0011] An example of porous silica is mesoporous silica in which pores (mesopores) having a diameter of 2 to 50 nm are regularly arranged.

[0012] The specific surface area of ​​porous silica is, for example, 500 to 2000 m 2 / g is preferable in terms of maintaining durability.

[0013] The mesoporous silica doped with a bacteriostatic metal can be produced according to the following method, which is known per se and described by the present inventors in JP-A-2020-15640, for example.

[0014] (Process 1) First, a surfactant and raw materials for doping mesoporous silica with a bacteriostatic metal are dissolved in a solvent and stirred, for example, at 30 to 200°C for 0.5 to 10 hours to form micelles in the surfactant.

[0015] The amount of surfactant dissolved in the solvent is, for example, 10 to 400 mmol / L, preferably 50 to 150 mmol / L, or, for example, 0.01 to 5.0 mol, preferably 0.05 to 1.0 mol, relative to 1 mol of the silica raw material added in Step 2 described below.

[0016] The surfactant may be a cationic surfactant, an anionic surfactant, or a nonionic surfactant, but is preferably a cationic surfactant such as an alkylammonium salt. The alkylammonium salt preferably has an alkyl group containing 8 or more carbon atoms, and from the perspective of industrial availability, an alkyl group containing 12 to 18 carbon atoms is more preferred. Specific examples of alkylammonium salts include hexadecyltrimethylammonium chloride, cetyltrimethylammonium bromide, stearyltrimethylammonium bromide, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, dodecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, didodecyldimethylammonium bromide, ditetradecyldimethylammonium bromide, didodecyldimethylammonium chloride, and ditetradecyldimethylammonium chloride. The surfactant may be used alone or in combination of two or more.

[0017] The amount of raw material dissolved in the solvent for doping the mesoporous silica with the bacteriostatic metal is, for example, 0.001 to 0.5 mol, preferably 0.01 to 0.1 mol, per 1 mol of the silica raw material added in step 2 described below.

[0018] As raw materials for doping mesoporous silica with a bacteriostatic metal, for example, nitrates, sulfates, chlorides, and oxychlorides of the bacteriostatic metal can be used. When the bacteriostatic metal is copper, it is preferable to use copper nitrate or copper chloride. When the bacteriostatic metal is zirconium, it is preferable to use zirconium oxychloride. When the bacteriostatic metal is cobalt, it is preferable to use cobalt nitrate. The raw materials for doping with the bacteriostatic metal may be used alone or in combination of two or more.

[0019] The solvent may be, for example, water, or a mixed solvent of water and a water-soluble organic solvent such as methanol, ethanol, diethylene glycol, or glycerin.

[0020] (Process 2) Next, the silica raw material is dissolved in the surfactant-forming micelle solution obtained in step 1, for example, at room temperature, and stirred until homogenous, allowing the silica raw material to accumulate on the surface of the surfactant micelles. The amount of silica raw material dissolved in the solution is, for example, 0.2 to 1.8 mol / L. Alternatively, when water or a mixed solvent of water and a water-soluble organic solvent is used as the solvent, the amount is, for example, 0.001 to 0.05 mol per 1 mol of water.

[0021] The silica raw material is not particularly limited as long as it forms an inorganic network consisting of siloxane bonds that constitute mesoporous silica by dehydration condensation. Specific examples of silica raw materials include tetraalkoxysilanes such as tetraethoxysilane, tetramethoxysilane, and tetra-n-butoxysilane, and sodium silicate. Tetraalkoxysilane is preferred, and tetraethoxysilane is more preferred. The silica raw materials may be used alone or in combination of two or more.

[0022] (Step 3) Next, the silica raw material accumulated on the surface of the surfactant micelles is dehydration-condensed to form an inorganic network consisting of siloxane bonds that constitute mesoporous silica, and a bacteriostatic metal is incorporated into the inorganic network by chemical bonding. The dehydration-condensation of the silica raw material can be carried out, for example, by adding a basic aqueous solution to the system to raise the pH, followed by stirring at room temperature for at least one hour. The basic aqueous solution is preferably added so that the pH is 8 to 14 immediately after addition, more preferably 9 to 11. Specific examples of basic aqueous solutions include aqueous sodium hydroxide, aqueous sodium carbonate, and aqueous ammonia, with aqueous sodium hydroxide being preferred. The basic aqueous solutions may be used alone or in combination of two or more. The dehydration-condensation of the silica raw material can also be carried out by adding an acidic aqueous solution such as an aqueous hydrochloric acid solution to the system to lower the pH, followed by stirring.

[0023] (Step 4) Finally, the surfactant micelles obtained in step 3, which form an inorganic network on the surface composed of siloxane bonds constituting the mesoporous silica and to which the bacteriostatic metal is chemically bonded, are collected as a precipitate by filtration, dried at 30 to 70°C for 10 to 48 hours, for example, and then calcined at 400 to 600°C for 1 to 10 hours to obtain the desired bacteriostatic metal-doped mesoporous silica. The bacteriostatic metal-doped mesoporous silica thus obtained may be pulverized in a mixer or mill as needed to obtain a desired particle size (e.g., a median diameter of 0.01 to 100 μm).

[0024] The addition of the raw material to the system for doping the bacteriostatic metal into the mesoporous silica is not limited to the above-mentioned step 1 in which the raw material is dissolved in a solvent together with a surfactant, but may be dissolved in a solution in step 2 or 3, as long as the formation of the inorganic network consisting of siloxane bonds that constitutes the mesoporous silica by dehydration condensation of the silica raw material in step 3 is completed.

[0025] The inorganic bacteriostatic slurry of the present invention can be prepared, for example, by suspending bacteriostatic metal-doped porous silica produced according to the above method in a dispersion medium. The bacteriostatic metal-doped porous silica may be suspended in a dispersion medium so that its content is, for example, 0.1 to 20 wt%, preferably 1 to 10 wt%. Suspending bacteriostatic metal-doped porous silica in a dispersion medium in an amount such that the bacteriostatic metal-doped porous silica content in the slurry exceeds 20 wt% may be difficult due to increased viscosity. On the other hand, a slurry containing less than 0.1 wt% bacteriostatic metal-doped porous silica may not fully exhibit its bacteriostatic effect. Water, for example, can be used as the dispersion medium. The water used as the dispersion medium may contain a water-soluble organic solvent, such as methanol, ethanol, or a polyhydric alcohol such as diethylene glycol or glycerin. However, the water content is preferably 50 wt% or more. The pH of the dispersion medium is, for example, 5 to 11, preferably 6 to 9. If the pH of the dispersion medium is below 5, the bacteriostatic metal doped in the porous silica may dissolve, whereas if the pH of the dispersion medium is above 11, the porous silica may dissolve.

[0026] The inorganic bacteriostatic slurry of the present invention has excellent durability of bacteriostatic effect. Although the reason for this is not entirely clear, as will be shown in the Examples below, the present inventors believe that this is related to the fact that the inorganic bacteriostatic slurry of the present invention exerts its bacteriostatic effect by retaining the bacteriostatic effect while chemically bonded and incorporated into the inorganic network consisting of siloxane bonds that constitute porous silica, rather than by the bacteriostatic effect being exerted by the bacteriostatic metal ions adsorbed on a carrier and detaching from the inorganic network, as in the case of conventional inorganic bacteriostatic slurries, which exert their bacteriostatic effect by detaching from the inorganic network.

[0027] In the inorganic bacteriostatic slurry of the present invention, when the bacteriostatic metal doped into the porous silica is copper, the copper-doped porous silica exhibits an excellent deodorizing effect against sulfur-containing odors, as reported by the present inventors in JP 2020-15640 A, and therefore has both deodorizing and bacteriostatic effects. Furthermore, when the bacteriostatic metal doped into the porous silica is zirconium, as reported by the present inventors in JP 2020-15640 A, zirconium has the effect of increasing the durability of the porous silica, and therefore the zirconium-doped porous silica has excellent durability.

[0028] In the inorganic bacteriostatic slurry of the present invention, the porous silica may be doped with a metal other than the bacteriostatic metal. A specific example of the metal other than the bacteriostatic metal is aluminum, which, like zirconium, has the effect of increasing the durability of the porous silica. The aluminum content in the porous silica doped with aluminum together with the bacteriostatic metal is, for example, 0.01 to 10 wt%, preferably 0.1 to 5 wt%, and more preferably the total amount including the bacteriostatic metal is up to 10 wt%.

[0029] A method for doping porous silica with aluminum together with a bacteriostatic metal includes, for example, dissolving the raw material (e.g., aluminum chloride) in a solvent or solution together with the raw material for doping mesoporous silica with a bacteriostatic metal in the above-mentioned method for producing mesoporous silica doped with a bacteriostatic metal. The amount of raw material for doping mesoporous silica with aluminum dissolved in the solvent or solution is, for example, 0.001 to 0.5 mol, preferably 0.01 to 0.1 mol, per mol of silica raw material added in step 2. However, it is more preferable that the total amount of the raw material for doping mesoporous silica with a bacteriostatic metal dissolved in the solvent or solution is a maximum of 0.5 mol per mol of silica raw material.

[0030] In addition, manganese or iron may be doped into porous silica as a metal other than the bacteriostatic metal. As reported by the present inventors in JP 2020-15640 A, doping porous silica with manganese or iron together with a bacteriostatic metal exhibits an excellent deodorizing effect against sulfur-containing odors. The manganese or iron content in porous silica doped with manganese or iron together with a bacteriostatic metal is, for example, 0.01 to 10 wt%, preferably 0.1 to 5 wt%, and more preferably the total amount including the bacteriostatic metal content (when aluminum is doped into porous silica, the total amount including the content of aluminum) is a maximum of 10 wt%.

[0031] A method for doping porous silica with manganese or iron together with a bacteriostatic metal includes dissolving the raw material (e.g., manganese chloride or iron chloride) in a solvent or solution together with the raw material for doping mesoporous silica with a bacteriostatic metal in the above-described method for producing mesoporous silica doped with a bacteriostatic metal. The amount of the raw material for doping mesoporous silica with manganese or iron dissolved in the solvent or solution is, for example, 0.001 to 0.5 mol, preferably 0.01 to 0.1 mol, per mol of silica raw material added in step 2. However, the total amount, including the amount of the raw material for doping mesoporous silica with a bacteriostatic metal dissolved in the solvent or solution (when aluminum is dissolved in the solvent or solution, the total amount includes the amount of aluminum dissolved) is preferably up to 0.5 mol per mol of silica raw material.

[0032] The inorganic bacteriostatic slurry of the present invention can be used as a material for imparting bacteriostasis to everyday items such as textile products, leather products, building materials, wood, paints, adhesives, plastics, films, ceramics, paper, pulp, metal processing oils, water treatment agents, cosmetics, stationery, toys, containers, caps, pouring devices, spouts, etc. The mode of use may be the same as the mode of use of conventionally known inorganic bacteriostatic slurries in which metal ions having bacteriostatic effect are adsorbed onto a carrier and suspended in a dispersion medium such as water, and for example, in the case of liquid items, it can be used by blending it with the item. [Example]

[0033] The present invention will be described in detail below with reference to examples, but the present invention should not be construed as being limited to the following description.

[0034] Example 1: Preparation of a slurry in which mesoporous silica doped with copper and aluminum as bacteriostatic metals is suspended in water, and its bacteriostatic effect Hexadecyltrimethylammonium chloride (surfactant), copper chloride (copper chloride), and aluminum chloride (aluminum chloride) were dissolved in water and stirred at 100°C for 1 hour. The mixture was then cooled to room temperature and tetraethoxysilane (silica precursor) was further dissolved and stirred until homogeneous. A basic aqueous solution of sodium hydroxide was then added to the reaction mixture, adjusting the pH to 9 immediately after addition, and the mixture was stirred at room temperature for 20 hours. The resulting precipitate was collected by filtration, dried at 50°C for 24 hours, and then calcined at 570°C for 5 hours to obtain the desired copper- and aluminum-doped mesoporous silica as a slightly bluish white powder.

[0035] The amounts of hexadecyltrimethylammonium chloride as a surfactant, copper chloride as a raw material for doping copper into mesoporous silica, aluminum chloride as a raw material for doping aluminum into mesoporous silica, and water as a solvent were as follows, relative to 1 mol of tetraethoxysilane as a silica raw material: Hexadecyltrimethylammonium chloride: 0.225 mol Copper chloride: 0.0204 mol Aluminum chloride: 0.0482 mol Water: 125mol To prepare a sodium hydroxide aqueous solution as a basic aqueous solution, 0.195 mol of sodium hydroxide was used per 1 mol of tetraethoxysilane as a silica raw material.

[0036] The copper and aluminum doped mesoporous silica obtained by the above method has a specific surface area of ​​1100 m 2 / g, pore volume 0.72 cm 3 The pore diameter was 2.6 nm (calculated using the BJH calculation based on nitrogen gas adsorption isotherm measurements at liquid nitrogen temperature using a Microtrackbell BELSORP MAX II multipoint method). Approximately 50 mg of copper- and aluminum-doped mesoporous silica was accurately weighed and dissolved in 4 mL of hydrochloric acid. The copper and aluminum concentrations in the hydrochloric acid solution were measured using an inductively coupled plasma optical emission spectrometer (Thermo Scientific ICP-OES). Based on the measurement results, the copper and aluminum contents in the copper- and aluminum-doped mesoporous silica were calculated to be 2.09 wt% and 2.00 wt%, respectively. The copper and aluminum doping of the mesoporous silica was confirmed using an X-ray photoelectron spectrometer (Thermo Scientific K-Alpha Surface Analysis) and a transmission electron microscope (JEOL JEM2010).

[0037] The copper- and aluminum-doped mesoporous silica obtained by the above method was pulverized in a mixer to a median diameter of approximately 25 to 31 μm (measured by a laser diffraction particle size distribution analyzer (SALD-3100, manufactured by Shimadzu Corporation), the same applies below). Five grams of the pulverized silica was then placed in a 250 mL polypropylene pot (Eye-Boy PP wide-mouth bottle, manufactured by AS ONE Corporation) with 95 g of water as a dispersion medium and 2 mm diameter alumina balls (manufactured by Nikkato Corporation, alumina purity: 93%, bulk density: 3.6 g / cm) as a medium. 3 The mixture was placed in a pot mill along with 210 g (approximately 14,000 pieces) of copper and aluminum doped mesoporous silica, and wet-pulverized for 8 hours. The alumina balls were then filtered off to obtain a slurry of copper and aluminum doped mesoporous silica suspended in water (containing 5 wt% copper and aluminum doped mesoporous silica with a median diameter of 0.50 μm).

[0038] The bacteriostatic effect of the resulting slurry, prepared by suspending the copper- and aluminum-doped mesoporous silica in water, was evaluated according to the preservative effectiveness test method described in the Japanese Pharmacopoeia. Specifically, 0.1 mL of each test bacterial solution was inoculated into 10 mL of the resulting slurry, which was prepared by suspending the copper- and aluminum-doped mesoporous silica in water. After stirring, the mixture was allowed to stand at 25°C for 28 days, and the viable bacterial counts were measured before and after the start of the test. The results are shown in Table 1.

[0039] [Table 1]

[0040] As is clear from Table 1, it was found that a slurry prepared by suspending copper- and aluminum-doped mesoporous silica in water exhibits a bacteriostatic effect against various types of fungi. Furthermore, the above-mentioned slurry containing 5 wt% copper- and aluminum-doped mesoporous silica showed almost no elution of copper ions into the liquid, and even after being left to stand for 55 days, the amount of elution was 10 ppm (measured using an inductively coupled plasma optical emission spectrometer (same as above)), demonstrating a sustained bacteriostatic effect.

[0041] The minimum inhibitory concentrations (MICs) of copper ions against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus are known to be 400 ppm, 400 ppm, and 200 ppm, respectively. However, considering these MICs, the bacteriostatic effect of the slurry obtained by suspending the above-mentioned copper- and aluminum-doped mesoporous silica in water is not due to the copper ions dissolved in the slurry. In other words, the bacteriostatic effect of the above-mentioned copper- and aluminum-doped mesoporous silica is believed to be due to the copper being chemically bonded and incorporated into the inorganic network of siloxane bonds that constitutes the mesoporous silica. This result was unexpected by those skilled in the art, including the present inventors.

[0042] Furthermore, when a slurry formed by suspending copper- and aluminum-doped mesoporous silica in water is incorporated into, for example, liquid hair care cosmetics or hair deodorants, as reported by the present inventors in JP 2020-15640 A, copper exerts an excellent deodorizing effect against sulfur-containing odors and also exhibits an excellent bacteriostatic effect, which has the great advantage of eliminating the need for additional preservatives or antibacterial agents. Additionally, it is noteworthy that the copper exerts its effect while chemically bonded and incorporated into the inorganic network of siloxane bonds that constitutes the mesoporous silica, preventing damage to hair (such as stiffness and dryness) that can be caused by eluted copper ions. From this viewpoint, assuming a slurry in which porous silica doped with a bacteriostatic metal is suspended in a dispersion medium so that the bacteriostatic metal content is, for example, 0.1 to 10 wt %, the amount of bacteriostatic metal ions eluted into the slurry when the slurry is allowed to stand at 25°C for 55 days is preferably 400 ppm or less, more preferably 200 ppm or less, even more preferably 100 ppm or less, and most preferably 50 ppm or less.

[0043] Example 2: Preparation of a slurry in which mesoporous silica doped with zirconium as a bacteriostatic metal and aluminum is suspended in water, and its bacteriostatic effect A slurry was obtained by suspending mesoporous silica doped with zirconium and aluminum as bacteriostatic metals in water in the same manner as in Example 1, except that zirconium oxychloride was used instead of copper chloride. The bacteriostatic effect was similar to that of the slurry obtained in Example 1 by suspending mesoporous silica doped with copper and aluminum as bacteriostatic metals in water, although to a different extent.

[0044] Example 3: Preparation of a slurry in which mesoporous silica doped with cobalt as a bacteriostatic metal and aluminum is suspended in water, and its bacteriostatic effect A slurry was obtained by suspending mesoporous silica doped with cobalt and aluminum as bacteriostatic metals in water in the same manner as in Example 1, except that cobalt nitrate was used instead of copper chloride. The bacteriostatic effect was similar to that of the slurry obtained in Example 1 by suspending mesoporous silica doped with copper and aluminum as bacteriostatic metals in water, although to a different extent.

[0045] Example 4: Preparation of a slurry in which mesoporous silica doped with copper as a bacteriostatic metal, aluminum, and manganese is suspended in water, and its bacteriostatic effect A slurry was obtained in which mesoporous silica doped with copper as a bacteriostatic metal, as well as aluminum and manganese, was suspended in water in the same manner as in Example 1, except that 0.0204 mol of manganese chloride, a raw material for doping mesoporous silica with manganese, was further dissolved in water as a solvent. The bacteriostatic effect was similar to that of the slurry obtained in Example 1 in which mesoporous silica doped with copper as a bacteriostatic metal, as well as aluminum, was suspended in water, although to a different extent. In addition, a deodorizing effect due to the doping of manganese was observed.

[0046] Application example 1: Production of water-based paint containing a slurry of copper- and aluminum-doped mesoporous silica suspended in water The copper and aluminum doped mesoporous silica obtained in Example 1 was suspended in water to form a slurry, which was then blended with an aqueous paint so that the content of copper and aluminum doped mesoporous silica was 0.5 wt %, thereby producing an aqueous paint that exhibits bacteriostatic effects. [Industrial Applicability]

[0047] INDUSTRIAL APPLICABILITY The present invention has industrial applicability in that it can provide an inorganic bacteriostatic slurry that has excellent durability of effect.

Claims

1. An inorganic slurry for bacteriostasis, comprising porous silica doped with aluminum and at least one bacteriostatic metal selected from copper, zirconium, cobalt, silver, and zinc suspended in a dispersion medium (in the above, porous silica doped with a bacteriostatic metal means porous silica in which a bacteriostatic metal is chemically bonded to and incorporated into the inorganic network consisting of siloxane bonds that constitute the porous silica).

2. 2. The inorganic bacteriostatic slurry according to claim 1, which is further doped with at least one metal selected from manganese and iron.

3. 3. The inorganic bacteriostatic slurry according to claim 1, wherein the dispersion medium is water.

4. An article comprising the bacteriostatic inorganic slurry according to any one of claims 1 to 3.

5. Use for bacteriostasis of a slurry obtained by suspending porous silica doped with aluminum and at least one bacteriostatic metal selected from copper, zirconium, cobalt, silver, and zinc in a dispersion medium (in the above, porous silica doped with a bacteriostatic metal means porous silica in which a bacteriostatic metal is incorporated by chemical bonding into the inorganic network consisting of siloxane bonds that constitutes the porous silica).

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