Antimicrobial glass, water treatment agent, and water treatment method

Abstract

An antimicrobial glass comprising SiO2 in an amount of 1-30 mass%, B2O3 in an amount of 40-70 mass%, Al2O3 in an amount of 0-20 mass%, K2O and / or Na2O in a total amount of 0-10 mass%, at least one selected from the group consisting of MgO, BaO, and ZnO in a total amount of 10-30 mass%, and Ag2O in an amount of 0.1-5 mass%, said amounts being expressed as oxides, wherein the ratio of B2O3 with respect to SiO2 is 1-20.

Description

Antibacterial glass, water treatment agent, water treatment method

[0001] The present invention relates to an antibacterial glass, a water treatment agent, and a water treatment method.

[0002] Known inorganic antibacterial agents include those in which antibacterial metals (e.g., silver, copper, and zinc) are supported on or encapsulated in carriers (e.g., zeolite, silica gel, and apatite). Compared to organic antibacterial agents, inorganic antibacterial agents are safer, have longer-lasting antibacterial effects, and are more heat-resistant.

[0003] In particular, glass as a carrier has the advantage that multiple metal components can be encapsulated in the matrix at any ratio. Furthermore, the release rate of the encapsulated substances can be controlled by adjusting the types and amounts of the components of the matrix. Therefore, many reports have been published on antibacterial glasses containing antibacterial metals in the matrix (e.g., Patent Documents 1 and 2).

[0004] International Publication No. 2011 / 125825 Japanese Patent Application Laid-Open No. 2013-155114

[0005] An object of the present invention is to provide antibacterial glass that has an excellent balance between antibacterial activity and durability (sustainability).

[0006] By adjusting the composition of the antibacterial glass to fall within a predetermined range, it is possible to provide antibacterial glass that has an excellent balance between antibacterial activity and durability.

[0007] The present invention includes the following embodiments: [1] The amount of SiO in terms of oxide: ２ The amount of B is 1 to 30% by mass, ２ O ３ The amount of Al is 40 to 70% by mass, ２ O ３ The amount of is 0 to 20% by weight, ２ O and / or Na ２ the total amount of O is 0 to 10 mass %, the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is 10 to 30 mass %, and Ag ２ The amount of O is 0.1 to 5% by mass, and B ２ O ３SiO ２ The ratio of B to B is 1 to 20. ２ O ３ SiO ２ [3] The antibacterial glass according to [1] or [2], wherein the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is 15 to 30 mass%. [4] SiO ２ The antibacterial glass according to any one of [1] to [3], wherein the amount of B is 4 to 10 mass%. ２ O ３ [6] The antibacterial glass according to any one of [1] to [4], wherein the amount of Al is 60 to 70 mass %. ２ O ３ [7] The antibacterial glass according to any one of [1] to [5], wherein the amount of ２ O and / or Na ２ The antibacterial glass according to any one of [1] to [6], wherein the total amount of O is 2 to 6 mass%. ２The antibacterial glass according to any one of [1] to [7], wherein the amount of O is 1.5 to 2.5 mass%. [9] The antibacterial glass according to any one of [1] to [8], wherein the antibacterial glass is in a granular form.

[10] The antibacterial glass according to [9], wherein the antibacterial glass has a mass of 0.01 to 10 g and a maximum diameter of 1 to 100 mm.

[11] The antibacterial glass according to any one of [1] to

[10] , wherein the antibacterial glass has an Ag elution rate in running water at 15°C of 0.1 to 30 μg / (g h).

[12] The antibacterial glass according to any one of [1] to

[11] , wherein the Ag elution rate in running water at 15°C is 0.5 to 10 μg / (g h).

[13] The antibacterial glass according to any one of [1] to

[12] , wherein the weight loss in running water at 15°C is 0.01 to 1 mg / (g h).

[14] The antibacterial glass according to any one of [1] to

[13] , which exhibits a weight loss in running water at 15°C of 0.01 to 0.3 mg / (g h).

[15] A water treatment agent comprising the antibacterial glass according to any one of [1] to

[14] .

[16] A water treatment method comprising contacting the water treatment agent according to

[15] with water.

[17] The water treatment method according to

[16] , wherein the water is running water.

[0008] The present invention can provide antibacterial glass that has an excellent balance between antibacterial activity and durability.

[0009] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these and various modifications are possible without departing from the gist of the present invention.

[0010] <Antibacterial Glass> One embodiment of the present invention is an antibacterial glass containing, in terms of oxide, SiO ２ The amount of B is 1 to 30% by mass, ２ O ３ The amount of Al is 40 to 70% by mass, ２ O ３ The amount of is 0 to 20% by weight, ２ O and / or Na ２the total amount of O is 0 to 10 mass %, the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is 10 to 30 mass %, and Ag ２ The amount of O is 0.1 to 5% by mass, and B ２ O ３ SiO ２ to a ratio of 1 to 20. (The components of this antibacterial glass are not limited to the specified components. That is, this antibacterial glass includes glasses containing the specified components as well as glasses containing other components.) The antibacterial glass can also be described as a soluble vitreous antibacterial agent.

[0011] The antibacterial glass according to this embodiment has an excellent balance between antibacterial activity and durability, and can therefore exert a stable antibacterial effect over a long period of time.

[0012] [SiO ２ ] SiO ２ forms a glass skeleton. ２ suppresses solubility and improves durability. ２ If the amount is too large, the glass becomes hard, which inhibits the elution of the antibacterial metal and makes it difficult to exert antibacterial activity.

[0013] B ２ O ３ When coexisting, SiO ２ If the amount is too large, the glass will not be a single-phase glass but will be a phase-separated glass, the solubility of the glass will be non-uniform, and the antibacterial activity will be unstable.

[0014] From the viewpoint of obtaining excellent antibacterial activity and durability, SiO ２ The amount of is 1 to 30% by mass, preferably 2 to 20% by mass, more preferably 3 to 15% by mass, and even more preferably 4 to 10% by mass.

[0015] [B ２ O ３ ] B ２ O ３ forms a glass skeleton. ２ O ３ enhances solubility and improves antibacterial activity.２ O ３ If the amount is too large, the glass becomes brittle and its durability decreases.

[0016] From the viewpoint of obtaining excellent antibacterial properties and durability, B ２ O ３ The amount of is 40 to 70% by mass, preferably 50 to 70% by mass, and more preferably 60 to 70% by mass.

[0017] [B ２ O ３ / SiO ２ ] B ２ O ３ SiO ２ Ratio to (B ２ O ３ / SiO ２ ) is an index of the solubility of the glass framework components. The larger this ratio, the higher the solubility of the glass and the easier it is to demonstrate antibacterial activity, but on the other hand, durability tends to decrease.

[0018] From the viewpoint of obtaining excellent antibacterial properties and durability, B ２ O ３ / SiO ２ is 1 to 20, preferably 3 to 18, more preferably 5 to 15, and even more preferably 8 to 15.

[0019] [Al ２ O ３ ] Al ２ O ３ forms a glass skeleton. ２ O ３ Is B ２ O ３ and / or SiO ２ When present as a main component, it improves the chemical durability of the glass. ２ O ３ If the amount is too large, the solubility of the glass decreases, the elution of the antibacterial metal is inhibited, and the antibacterial effect is not easily exerted.

[0020] From the viewpoint of obtaining excellent antibacterial properties and durability, Al ２ O ３ The amount of is 0 to 20% by mass, preferably 0 to 15% by mass, and more preferably 0 to 10% by mass.

[0021] [K ２ O, Na ２ O] K, an alkali metal oxide ２ O and Na ２ O increases the solubility of glass and improves antibacterial activity. On the other hand, if the amount of alkali metal oxide is too large, the glass becomes brittle and its durability decreases. Furthermore, if the amount of alkali metal oxide is too large, the glass itself or objects in contact with the glass may be discolored.

[0022] From the viewpoint of obtaining excellent antibacterial properties and durability, K ２ O and / or Na ２ The total amount of O is 0 to 10% by mass, preferably 1 to 8% by mass, and more preferably 2 to 6% by mass.

[0023] K ２ O and Na ２ Only one of K and O may be contained, or both may be contained. When both are contained, the amount is ２ O and Na ２ O is the total amount.

[0024] [MgO, BaO, ZnO] MgO, BaO, and ZnO are incorporated into the glass skeleton components to stabilize the glass and improve durability. ZnO also exhibits antibacterial properties. On the other hand, if the amounts of MgO, BaO, and ZnO are too large, the solubility of the glass decreases, making it difficult to exhibit antibacterial properties.

[0025] From the viewpoint of obtaining excellent antibacterial activity and durability, the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is 10 to 30 mass%, preferably 12 to 30 mass%, and more preferably 15 to 30 mass%.

[0026] From the viewpoint of further enhancing antibacterial activity, the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is preferably 10 to 20 mass %, and from the viewpoint of further enhancing durability, the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is preferably 20 to 30 mass %.

[0027] The composition may contain only one of MgO, BaO, and ZnO, or may contain multiple components. When multiple components are contained, the amount mentioned above is the total amount of the multiple components.

[0028] [Ag ２ O] Ag ２ O is an antibacterial metal that exerts antibacterial activity. Ag ２ If O is added in excess, it will precipitate from the glass.

[0029] From the viewpoint of obtaining excellent antibacterial properties, Ag ２ The amount of O is 0.1 to 5 mass %, preferably 0.5 to 3 mass %, and more preferably 1.5 to 2.5 mass %.

[0030] [Optional Components] The antibacterial glass may further contain optional components, such as CuO, NiO, and CoO. These components can be used to color the glass (CuO: blue, NiO: amber, CoO: purple).

[0031] The amount of CuO is preferably 0 to 5 mass %, more preferably 0 to 3 mass %, and even more preferably 0 to 1 mass %.

[0032] The amount of NiO is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, and even more preferably 0 to 1% by mass.

[0033] The amount of CoO is preferably 0 to 5 mass %, more preferably 0 to 3 mass %, and even more preferably 0 to 1 mass %.

[0034] [Shape] The shape of the antibacterial glass is not particularly limited, but is preferably granular. The glass particles preferably have a shape (e.g., hemispherical, approximately hemispherical, conical, and truncated conical) with a flat bottom and an upper portion that bulges upward from the bottom. Conventional antibacterial glass has generally been cullet- or flake-shaped, but such shapes have problems such as the danger of minute glass fragments, the instability of Ag elution due to glass shattering, and low water permeability when contacted with water. On the other hand, granular glass can avoid these problems.

[0035] From the viewpoint of improving the contact rate and water permeability when the antibacterial glass is brought into contact with water, and from the viewpoint of appropriately controlling the amount of elution of the antibacterial glass, the maximum diameter of the glass particles is preferably 1 to 100 mm, more preferably 3 to 20 mm, even more preferably 3 to 10 mm, and particularly preferably 3 to 6 mm.

[0036] From the viewpoints of improving the contact rate and water permeability when the antibacterial glass is brought into contact with water, and of appropriately controlling the amount of elution of the antibacterial glass, the height of the glass particles is preferably 1 to 5 mm, more preferably 1 to 4 mm, and even more preferably 1.5 to 3 mm. The height of the glass particles is measured in the vertical direction from the horizontal plane where the maximum diameter is measured.

[0037] From the viewpoint of improving the contact rate and water permeability when the antibacterial glass is brought into contact with water, and from the viewpoint of appropriately controlling the amount of elution of the antibacterial glass, the mass per glass particle is preferably 0.01 to 10 g, more preferably 0.01 to 5 g, and even more preferably 0.02 g to 0.5 g.

[0038] The antibacterial glass may be used as is or in combination with other materials. For example, the antibacterial glass may be incorporated into resins or fibers, or may be attached to fibers or articles using a binder or adhesive.

[0039] [Synthesis Method] The synthesis method of the antibacterial glass is not particularly limited, and any known method may be used. For example, raw materials may be mixed to obtain a desired glass composition, and the mixture may be heated and melted. For example, WO 2011 / 125825 may be referred to as a method for forming the desired shape.

[0040] [Uses] The uses of the antibacterial glass are not particularly limited. For example, it can be used in connection with electrical appliances (e.g., dishwashers, refrigerators, washing machines, kettles, rice cookers, air conditioners, air purifiers, dehumidifiers, and humidifiers), toiletry products (e.g., toilet water, bathtubs, bathrooms, chamber pots, waste containers, and baths), kitchenware (e.g., food waste containers and drain plugs), toys (e.g., water guns, bath toys, and cooking toys), swimming pools, reservoirs, aquariums, and antibacterial sprays.

[0041] The antibacterial glass is preferably used for water treatment (i.e., as a "water treatment agent"), and although not particularly limited thereto, the antibacterial glass is preferably used for treating drain water generated from electrical appliances.

[0042] The use of antibacterial glass is not limited to the treatment of bacteria, but can also be used to treat viruses, mold, or algae.

[0043] [Performance] The amount of Ag eluted from the antibacterial glass in running water at 15° C. is preferably 0.1 to 30 μg / (g·h), and more preferably 0.5 to 10 μg / (g·h).

[0044] From the viewpoint of further enhancing antibacterial activity, the amount of Ag elution is preferably 2 to 10 μg / (g·h), and from the viewpoint of further enhancing durability, the amount of Ag elution is preferably 0.5 to 2 μg / (g·h).

[0045] The method for measuring the amount of Ag elution is as described in the Examples below.

[0046] The weight loss of the antibacterial glass in running water at 15° C. is preferably 0.01 to 1 mg / (g·h), and more preferably 0.01 to 0.3 mg / (g·h).

[0047] From the viewpoint of increasing antibacterial activity, the weight loss is preferably 0.1 to 0.3 mg / (g·h), and from the viewpoint of increasing durability, the weight loss is preferably 0.01 to 0.1 mg / (g·h).

[0048] The method for measuring the amount of Ag elution is as described in the Examples below.

[0049] <Water Treatment Method> One embodiment of the present invention relates to a water treatment method that includes bringing the above-described antibacterial glass (water treatment agent) into contact with water.

[0050] The method for contacting the antibacterial glass with water is not particularly limited, but it is preferable to bring the antibacterial glass into contact with flowing water (particularly, continuously discharged drain water). ＋ Ions can be supplied stably for a long period of time.

[0051] When the antibacterial glass is brought into contact with flowing water, it is preferable to place a water-permeable container containing a plurality of antibacterial glass particles in contact with the flowing water. Examples of water-permeable containers include nonwoven bags, mesh bags, and porous resin containers.

[0052] The present invention will be described in more detail below using examples and comparative examples, but the technical scope of the present invention is not limited to these.

[0053] Various values ​​in the examples may be used as preferred lower or upper limits in the embodiments of the present invention. Two values ​​of the same type in the examples may be appropriately combined to form a preferred range of values.

[0054] <Production of antibacterial glass> A mixture of glass raw materials formulated to obtain the composition shown in Table 1 was heated and melted at 1200°C. The melt was cooled and shaped using a metal cooling and shaping roller with a hemispherical depression 5 mm in diameter on one side. The obtained glass was crushed by beating and further dry-crushed using a ball mill for 1 hour, and then fine powder was sieved off using a wire mesh with 2.8 mm openings to obtain antibacterial glass.

[0055]

[0056] <Evaluation> [Running Water Test] 5 g of antibacterial glass was placed in a 5 cm x 4 cm polyethylene mesh bag (mesh opening: approximately 0.2 mm), and the open end was closed by heat sealing. The polyethylene mesh bag containing the antibacterial glass was placed in a plastic container (volume: approximately 40 cm) cut in half. ３ Pure water at 15°C was poured into the plastic container at a rate of 1.4 L / h, and the liquid that overflowed from the plastic container was collected as treated water. ＋ The ion concentration was measured using an ICP-OES (inductively coupled plasma optical emission spectrometer) and normalized to a value per 1 g of antibacterial glass and 1 hour of elution time to calculate the amount of Ag elution (μg / (g·h)).

[0057] After one week (168 hours), the remaining antibacterial glass was collected, dried at room temperature, and weighed. The weight loss of the antibacterial glass was calculated by normalizing the weight loss per 1 g of antibacterial glass and per hour of dissolution time (mg / (g h)). The weight loss is an index of durability.

[0058] For Examples 1 to 3 and Comparative Examples 1 and 4, the change in Ag concentration in the treated water over time was also confirmed.

[0059] [Antibacterial Test] NB medium was added to the sterilized purified water and the treated water collected after one week at a concentration of 1 / 500, and Escherichia coli was cultured at a cell count of 1 × 10 ５ The solution was adjusted to a concentration of 1000 / mL and added. After standing at 27°C for 24 hours, the number of E. coli bacteria was measured by the plate smear method using nutrient agar medium. The antibacterial activity value was calculated using the following formula: Antibacterial activity value = Log (number of E. coli bacteria per mL of sterilized purified water) - Log (number of E. coli bacteria per mL of treated water)

[0060] [Expected durability] When evaluating the durability of the antibacterial glass, 1,569 hours, which is the number of outdoor temperatures in Tokyo that require cooling per year, was used as the annual air conditioning operating time, with reference to "JIS C 9612:2013 Room Air Conditioner." The expected durability of the antibacterial glass was calculated using the following formula: Expected durability (years) = 1,000 (mg / g) / (weight loss of antibacterial glass (mg / (g h)) × 1,569 (h / year))

[0061] [Results] The results of the flow-through test and the antibacterial test are shown in Tables 2 and 3.

[0062]

[0063]

[0064] [Evaluation] All of the antibacterial glasses of the Examples had an excellent balance of antibacterial activity and durability due to the appropriate ratios of the various components. In particular, the antibacterial glass of Example 1 had high antibacterial activity and sufficient durability, and the antibacterial glass of Example 2 had sufficient antibacterial activity and high durability.

[0065] The antibacterial glasses of Comparative Examples 1 and 2 are, for example, B ２ O ３ / SiO ２ The ratio, the amount of MgO+BaO+ZnO, etc. were not appropriate, so the glass was excessively dissolved, resulting in insufficient durability. Furthermore, in the antibacterial glass of Comparative Example 1, the amount of Ag eluted over time was unstable, making it difficult to stably exert antibacterial activity.

[0066] The antibacterial glass of Comparative Example 3 contains Al ２ O ３ Because it contained an excess of Ag ＋ The ions were difficult to elute, and the antibacterial effect was insufficient.

[0067] The antibacterial glass of Comparative Example 4 was ２ O + Na ２ Since the glass contained an excessive amount of O and had a small amount of MgO+BaO+ZnO, the glass was excessively dissolved and the durability was insufficient.

[0068] The antibacterial glass of Comparative Example 5 contained an excess of MgO+BaO+ZnO, and therefore Ag ＋ The ions were difficult to elute, and the antibacterial effect was insufficient.

[0069] The antibacterial glass of Comparative Example 6 was B ２ O ３ / SiO ２ The ratio was too high, causing excessive glass melting and insufficient durability.

Claims

1. The amount converted to oxide is SiO ２ The amount of B is 1 to 30% by mass, ２ O ３ The amount of Al is 40 to 70% by mass, ２ O ３ The amount of is 0 to 20% by weight, ２ O and / or Na ２ the total amount of O is 0 to 10 mass %, the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is 10 to 30 mass %, and Ag ２ The amount of O is 0.1 to 5% by mass, and B ２ O ３ SiO ２ The antibacterial glass of claim 1, wherein the ratio of 2. B ２ O ３ SiO ２ The antimicrobial glass of claim 1 , wherein the ratio of 3. The antibacterial glass according to claim 1, wherein the total amount of at least one selected from the group consisting of MgO, BaO, and ZnO is 15 to 30 mass%.

4. SiO ２ The antimicrobial glass of claim 1 , wherein the amount of 5. B ２ O ３ The antimicrobial glass of claim 1 , wherein the amount of 6. Al ２ O ３ The antimicrobial glass of claim 1 , wherein the amount of 7. K ２ O and / or Na ２ The antibacterial glass according to claim 1 , wherein the total amount of O is 2 to 6 mass %.

8. Ag ２ The antimicrobial glass of claim 1 , wherein the amount of O is 1.5 to 2.5 wt %.

9. The antimicrobial glass of claim 1, wherein the antimicrobial glass is in a granular form.

10. The antibacterial glass according to claim 9, wherein the antibacterial glass has a mass of 0.01 to 10 g and a maximum diameter of 1 to 100 mm.

11. The antibacterial glass according to claim 1, wherein the amount of Ag eluted in running water at 15°C is 0.1 to 30 μg / (g·h).

12. The antibacterial glass according to claim 11, wherein the amount of Ag eluted in running water at 15°C is 0.5 to 10 μg / (g·h).

13. The antibacterial glass according to claim 1, wherein the weight loss in running water at 15°C is 0.01 to 1 mg / (g·h).

14. The antibacterial glass according to claim 13, wherein the weight loss in running water at 15°C is 0.01 to 0.3 mg / (g·h).

15. A water treatment agent comprising the antibacterial glass according to any one of claims 1 to 14.

16. A method for treating water, comprising contacting water with the water treatment agent according to claim 15.

17. The water treatment method according to claim 16, wherein the water is flowing water.

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