Aqueous metal composition

Abstract

Provided is an aqueous metal composition in which the generation of precipitates is suppressed and agglomeration does not readily occur even when stored for a long period of time. The present invention is an aqueous metal composition containing an aqueous medium, silver, and at least one metal M other than the silver, the metal M being a metal having antibacterial and / or antiviral properties, the content ratio of the metal M relative to the aqueous medium being 0.1-100,000 ppm by mass, and the mass ratio of chlorine to silver (Cl / Ag) being 0.05 or less.

Description

Technical Field

[0001] The present invention relates to an aqueous metal composition comprising an aqueous medium and a metal. Background Art

[0002] Aqueous metal compositions containing an aqueous medium and a metal include, for example, dispersions containing nanoscale metal particles or solutions containing metals dissolved in ionic form. Aqueous metal compositions possess unique properties not found in bulk metals, leading to their widespread use in various fields, including electronic materials, magnetic materials, and catalyst materials. Depending on the type and form of the metal, these compositions can also exhibit antibacterial, antiviral, and deodorizing properties (e.g., see Patent Document 1).

[0003] Such aqueous metal compositions may sometimes produce aggregation and precipitation, and there is a problem that the generation of aggregation and precipitation becomes more pronounced particularly with the passage of time and storage conditions. Therefore, it is desired to produce aqueous metal compositions with improved metal dispersibility and solubility.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2017 / 082201 Summary of the Invention

[0007] Technical problem that the invention aims to solve

[0008] For example, when the aqueous metal composition is a dispersion of metal nanoparticles, known methods for improving the dispersibility of the dispersion include adding a dispersion stabilizer and preventing aggregation by surface treating the metal particles.

[0009] However, even with the addition of a dispersion stabilizer, it is difficult to stabilize the dispersibility of metal nanoparticles, and there is a problem of decreased stability over time. Furthermore, excessive addition of a dispersion stabilizer can sometimes hinder the effects of the metal nanoparticles. Surface treatment of metal particles also requires a surface treatment step, which complicates the manufacturing process. This problem of decreased stability of aqueous metal compositions occurs not only in dispersions of metal nanoparticles but also in solutions of metal ions.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aqueous metal composition that suppresses the generation of precipitates and is less likely to aggregate even when stored for a long period of time.

[0011] Technical means to solve the problem

[0012] The present inventors have conducted intensive studies to achieve the above-mentioned object and, as a result, have found that the above-mentioned object can be achieved by adjusting the amount of chlorine contained in the composition to an appropriate range, thereby completing the present invention.

[0013] That is, the present invention includes, for example, the subject matters described in the following items.

[0014] Item 1

[0015] An aqueous metal composition comprising an aqueous medium, silver, and at least one metal M other than silver.

[0016] The metal M is a metal having antibacterial and / or antiviral properties.

[0017] The content ratio of the metal M relative to the aqueous medium is 0.1 mass ppm or more and 100,000 mass ppm or less,

[0018] The mass ratio of chlorine to silver (Cl / Ag) is 0.05 or less.

[0019] Item 2

[0020] The aqueous metal composition according to item 1, wherein

[0021] The silver and metal M are in the form of particles.

[0022] Item 3

[0023] The aqueous metal composition according to item 1, wherein

[0024] The silver and metal M are ions.

[0025] Item 4

[0026] The aqueous metal composition according to any one of items 1 to 3, wherein

[0027] The metal M is at least one selected from the group consisting of platinum, gold, copper, zinc, nickel, and aluminum.

[0028] Item 5

[0029] The aqueous metal composition according to any one of items 1 to 3, wherein

[0030] The metal M is at least one selected from the group consisting of platinum, gold, copper and zinc.

[0031] Effects of the Invention

[0032] The aqueous metal composition of the present invention suppresses the generation of precipitates and is less likely to aggregate even when stored for a long period of time. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present invention will be described in detail. It should be noted that in this specification, the expressions "comprising" and "including" include concepts such as "comprising", "including", "substantially including", and "including only".

[0034] The aqueous metal composition of the present invention comprises an aqueous medium, silver, and at least one metal M other than the silver. The metal M is a metal having antibacterial and / or antiviral properties, the content of the metal M relative to the aqueous medium is from 0.1 ppm to 100,000 ppm by mass, and the mass ratio of chlorine to silver (Cl / Ag) is from 0.05 to 0.05. The mass ratio of chlorine to silver (Cl / Ag) is the value obtained by dividing the mass of chlorine contained in the aqueous metal composition by the mass of silver (Ag) contained in the aqueous metal composition.

[0035] The aqueous metal composition of the present invention constructed as described above suppresses the generation of precipitates and is less likely to aggregate even when stored for a long period of time.

[0036] In the aqueous metal composition of the present invention, the aqueous medium is not particularly limited. Examples thereof include water, lower alcohols having 1 to 3 carbon atoms, or mixed solvents thereof. Various types of water may be used, including distilled water, tap water, industrial water, ion-exchanged water, deionized water, pure water, and electrolyzed water. Among these, ion-exchanged water, deionized water, pure water, and electrolyzed water are preferred because they are less likely to incorporate chlorine.

[0037] From the viewpoint of improving the dispersion stability of the aqueous metal composition, the aqueous medium may contain 90% by mass or more of water, and particularly preferably 99% by mass or more. The aqueous medium may consist solely of water.

[0038] The aqueous metal composition of the present invention comprises silver and metal M as essential components. As described above, metal M is a metal having antibacterial and / or antiviral properties. That is, metal M is an antibacterial metal and / or antiviral metal. The type of metal M is not particularly limited as long as it has antibacterial and / or antiviral properties, and a wide range of known antibacterial metals and antiviral metals can be exemplified. It should be noted that in the present invention, antibacterial properties are not limited to bacteria, but also encompass a wide range of microorganisms.

[0039] Examples of the metal M include various noble metals, transition metal elements having antimicrobial properties, and metals such as zinc. Examples of the metal M include platinum, gold, silver, copper, zinc, cobalt, aluminum, nickel, palladium, molybdenum, tungsten, silicon, titanium, chromium, manganese, tin, tantalum, lead, and zirconium.

[0040] The metal M is preferably at least one selected from the group consisting of platinum, gold, silver, copper, zinc, cobalt, aluminum, nickel, palladium, molybdenum, tungsten, lead, and zirconium, more preferably at least one selected from the group consisting of platinum, gold, silver, zinc, copper, nickel, and aluminum, and even more preferably at least one selected from the group consisting of platinum, gold, copper, and zinc. In these cases, the aqueous metal composition is more likely to suppress the formation of precipitates and is less likely to aggregate even during long-term storage. A more preferred metal M is at least one selected from the group consisting of platinum, gold, and copper, and a particularly preferred metal M is at least one selected from the group consisting of platinum and gold, with platinum being particularly preferred.

[0041] In the aqueous metal composition of the present invention, silver and metal M are preferably in a granular or ionic form. Specifically, one embodiment of the aqueous metal composition of the present invention includes an aqueous metal composition in which the silver and metal M are in a granular form. Another embodiment of the aqueous metal composition of the present invention includes an aqueous metal composition in which the silver and metal M are in an ionic form.

[0042] When silver and metal M are in the form of particles, the aqueous metal composition of the present invention contains silver particles and metal M particles.

[0043] Silver particles are particles composed of silver (Ag). They are typically formed from a single element of silver, but may also contain silver compounds such as silver oxides. Silver particles may also contain alloys of silver and other metal elements. Silver particles are preferably formed from a single element of silver (Ag).

[0044] The metal M particles are particles composed of metal M and are generally formed of a single substance of metal M. However, they may also include a compound of metal M, such as an oxide of metal M. The metal M particles may also include an alloy of metal M and other metal elements. The metal M particles are preferably formed of a single substance of metal M.

[0045] An example of an embodiment of silver particles and metal M particles is a dispersion of silver particles and platinum particles dispersed in an aqueous medium. This dispersion not only exhibits exceptionally excellent antibacterial and / or antiviral properties, but also significantly suppresses the formation of precipitates and is particularly resistant to aggregation even during long-term storage.

[0046] The average primary particle size of the silver particles and the metal M particles is not particularly limited, and for example, both are 0.1 to 1000 nm. The average primary particle size mentioned here refers to the value measured using a zeta potential measuring device (Zeta Sensor No. ZS90, manufactured by Malvern). The average primary particle size of the silver particles and the metal M particles is preferably 1 to 800 nm, more preferably 5 to 500 nm, and further preferably 15 to 350 nm. The average primary particle sizes of the silver particles and the metal M particles may be different from each other, and the preferred ranges of the average primary particle sizes may also be different.

[0047] When silver and metal M are ions, the aqueous metal composition of the present invention contains silver ions and ions of metal M. In this case, when the ions of each metal have multiple valences, the valences are not particularly limited.

[0048] The counter ions (anions) of the silver ions are not particularly limited, and examples thereof include organic carboxylate ions such as nitrate ions, nitrite ions, halogen ions, sulfate ions, sulfite ions, phosphate ions, hydrogen phosphate ions, acetate ions, citrate ions, hydrogen citrate ions, and sulfonate ions such as alkyl sulfonate ions, benzenesulfonate ions, and alkylbenzenesulfonate ions. The counter ions (anions) of the metal M ions are not particularly limited, and examples thereof include organic carboxylate ions such as nitrate ions, nitrite ions, halogen ions, sulfate ions, sulfite ions, phosphate ions, hydrogen phosphate ions, acetate ions, citrate ions, hydrogen citrate ions, and sulfonate ions such as alkyl sulfonate ions, benzenesulfonate ions, and alkylbenzenesulfonate ions. It should be noted that the mass ratio of chlorine to silver (Cl / Ag) of the aqueous metal composition of the present invention may also contain chloride ions within a range not exceeding 0.05.

[0049] As an example of an embodiment of silver ions and metal M ions, a solution obtained by dissolving silver ions and platinum ions in an aqueous medium can be cited. In addition to exhibiting particularly excellent antibacterial and / or antiviral properties, this solution can also particularly suppress the formation of precipitates, making it particularly difficult to produce coagulation even when stored for a long time.

[0050] In the aqueous metal composition of the present invention, the content of the metal M relative to the aqueous medium is 0.1 mass ppm or more and 100,000 mass ppm or less, regardless of whether the metals are particles or ions. If the content of the metal M relative to the aqueous medium is less than 0.1 mass ppm, the effect of the metal M may not be fully exerted. If the content of the metal M exceeds 100,000 mass ppm, the aqueous metal composition of the present invention may be prone to precipitate and may also be prone to aggregation during long-term storage.

[0051] Conventionally, if the content ratio of the metal M relative to the aqueous medium increases (for example, tens of mass ppm or more), there has been a problem of easily generating precipitates and easily causing aggregation during long-term storage. In this regard, the aqueous metal composition of the present invention avoids such problems by adjusting the mass ratio of chlorine to silver (Cl / Ag) to an appropriate range.

[0052] In the aqueous metal composition of the present invention, when each metal is in the form of particles, the content ratio of the above-mentioned metal M relative to the above-mentioned aqueous medium is preferably 0.1 mass ppm or more, more preferably 1 mass ppm or more, further preferably 10 mass ppm or more, and particularly preferably 20 mass ppm or more. In addition, it is preferably 10,000 mass ppm or less, more preferably 1,000 mass ppm or less, further preferably 500 mass ppm or less, particularly preferably 300 mass ppm or less, and can also be 100 mass ppm or less.

[0053] In the aqueous metal composition of the present invention, when each metal is an ion, the content ratio of the above-mentioned metal M relative to the above-mentioned aqueous medium is preferably 0.1 mass ppm or more, more preferably 1 mass ppm or more, further preferably 10 mass ppm or more, and particularly preferably 20 mass ppm or more. In addition, it is preferably 10,000 mass ppm or less, more preferably 1,000 mass ppm or less, further preferably 500 mass ppm or less, particularly preferably 300 mass ppm or less, and can also be 100 mass ppm or less.

[0054] In the aqueous metal composition of the present invention, when each metal is in the form of particles, the content ratio of silver relative to the above-mentioned aqueous medium is, for example, 0.1 mass ppm or more, preferably 1 mass ppm or more, more preferably 2 mass ppm or more, further preferably 5 mass ppm or more, and particularly preferably 10 mass ppm or more. In addition, it is, for example, 100,000 mass ppm or less, preferably 50,000 mass ppm or less, more preferably 10,000 mass ppm or less, further preferably 1,000 mass ppm or less, particularly preferably 300 mass ppm or less, and may also be 100 mass ppm or less.

[0055] In the aqueous metal composition of the present invention, when each metal is an ion, the content ratio of silver relative to the above-mentioned aqueous medium is, for example, 0.1 mass ppm or more, preferably 1 mass ppm or more, more preferably 2 mass ppm or more, further preferably 5 mass ppm or more, and particularly preferably 10 mass ppm or more. In addition, it is, for example, 100,000 mass ppm or less, preferably 50,000 mass ppm or less, more preferably 10,000 mass ppm or less, further preferably 1,000 mass ppm or less, particularly preferably 300 mass ppm or less, and may also be 100 mass ppm or less.

[0056] In the aqueous metal composition of the present invention, when each metal is in the form of particles, the content ratio of silver to metal M is not particularly limited. For example, the content of the metal M can be 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, further preferably 10 parts by mass or more, particularly preferably 30 parts by mass or more, and can be 100 parts by mass or more. In addition, it can be 10,000 parts by mass or less, preferably 5,000 parts by mass or less, more preferably 4,000 parts by mass or less, further preferably 3,500 parts by mass or less, and particularly preferably 1,000 parts by mass or less, relative to 100 parts by mass of silver.

[0057] In the aqueous metal composition of the present invention, when each metal is an ion, the content ratio of silver to metal M is not particularly limited. For example, the content of the metal M can be 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, further preferably 10 parts by mass or more, and particularly preferably 40 parts by mass or more, relative to 100 parts by mass of silver. Alternatively, the content of the metal M can be 4000 parts by mass or less, preferably 400 parts by mass or less, more preferably 200 parts by mass or less, further preferably 100 parts by mass or less, and particularly preferably 80 parts by mass or less.

[0058] As described above, the aqueous metal composition of the present invention has a chlorine to silver mass ratio (hereinafter referred to as "Cl / Ag") of 0.05 or less. When the Cl / Ag value exceeds 0.05, the aqueous metal composition of the present invention is prone to precipitate formation and may also aggregate during long-term storage. Therefore, by setting the Cl / Ag value to 0.05 or less, the aqueous metal composition of the present invention suppresses precipitate formation and enables long-term storage.

[0059] From the perspective of not easily generating coagulation and precipitation even when stored for a long time, the value of Cl / Ag is preferably 0.04 or less, more preferably 0.03 or less, further preferably 0.02 or less, and particularly preferably 0.015 or less. The value of Cl / Ag can be 0.01 or less. In addition, the value of Cl / Ag of the aqueous metal composition of the present invention can be 0. That is, the aqueous metal composition of the present invention may not contain Cl (chlorine). The aqueous metal composition does not contain Cl, which means that the content of Cl is 0 mass ppm, and further means that chlorine that can be detected by elemental analysis cannot be detected (that is, below the detection limit). If the lower limit of the Cl / Ag value is represented, it is, for example, about 0.001.

[0060] The method for adjusting the Cl / Ag value to 0.05 or less is not particularly limited, and various methods can be applied. For example, a method for adjusting the amount of chlorine and silver in the aqueous metal composition contained after production according to the types of raw materials and aqueous media used when producing the aqueous metal composition of the present invention and their usage amounts can be cited. That is, according to the production conditions when producing the aqueous metal composition of the present invention, the Cl / Ag value can be adjusted to 0.05 or less. This production method will be described later. In addition, a method for adjusting the Cl / Ag value to 0.05 or less by adding chlorine to the aqueous metal composition, a method for adjusting the Cl / Ag value to 0.05 or less by removing the chlorine contained in the aqueous metal composition, a method for adjusting the Cl / Ag value to 0.05 or less by adding silver to the aqueous metal composition, etc. can be cited.

[0061] The method for quantifying the Cl / Ag value of the aqueous metal composition of the present invention is not particularly limited, and for example, a wide range of known methods can be used. In particular, in the present invention, the Cl / Ag value of the aqueous metal composition is quantified by quantifying the metal components (e.g., platinum and silver) by ICP-MS analysis and the chloride ions by ion chromatography.

[0062] The sample solution used in the quantification of metal components based on ICP-MS analysis is prepared according to the following steps. First, weigh about 0.4 g of the sample collection amount and heat to remove the solvent. Before drying, add 0.1 mL of sulfuric acid and 1 mL of nitric acid and heat to decompose. Then, heat and concentrate until white sulfuric acid smoke is produced. Add 2 mL of aqua regia and further heat to decompose. Then, heat and concentrate again until white sulfuric acid smoke is produced. Add 10 mL of aqua regia and heat to dissolve it. After cooling, accurately measure it with aqua regia to 20 mL and use it as the sample solution. The measurement conditions of ICP-MS analysis are to dilute the above sample solution at a specified ratio to prepare a dilution. The dilution is injected into the ICP-MS device to measure the concentration of each metal. In the quantification of chloride ions based on ion chromatography, the sample solution obtained as described above is diluted at a specified ratio to prepare a dilution. The dilution is injected into the ion chromatography device to measure the concentration of each metal.

[0063] When the method for producing the aqueous metal composition of the present invention is clarified, the Cl / Ag value of the aqueous metal composition is determined based on the amount of chlorine and the amount of metal contained in the raw materials.

[0064] The aqueous metal composition of the present invention may contain metal particles or metal ions other than silver and metal M. When other metal particles or metal ions are contained, their content is not particularly limited, but is 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less, relative to the total amount of silver and metal M. The metals contained in the aqueous metal composition of the present invention may consist solely of silver and metal M. In this case, the metals inevitably contained in the aqueous metal composition are permitted.

[0065] The pH of the aqueous metal composition of the present invention is not particularly limited. For example, the pH is preferably 7 or less, more preferably 6 or less, and particularly preferably 5 or less.

[0066] The aqueous metal composition of the present invention may contain various additives as long as the effects of the present invention are not impaired.

[0067] The aqueous metal composition of the present invention contains an aqueous medium, silver, and at least one metal M other than silver in predetermined amounts, and has a Cl / Ag ratio of 0.05 or less, thereby suppressing the generation of precipitates and preventing aggregation even during long-term storage.

[0068] Whether or not there is a precipitate in the aqueous metal composition of the present invention immediately after production can be determined by visually observing the aqueous metal composition and judging whether or not there is a precipitate.

[0069] Whether the aqueous metal composition of the present invention has precipitates can be determined by storing the aqueous metal composition under the following storage conditions and then visually observing the aqueous metal composition to determine whether precipitates are observed.

[0070] [Storage conditions]

[0071] 100 mL of the aqueous metal composition was sealed in a 110 mL container in an air atmosphere, and the container was placed in a thermostatic bath maintained at 40° C. for storage for 3 weeks and 6 weeks.

[0072] If no precipitate is observed after storage for 3 weeks or more under the above storage conditions, a composition that can be generally used practically without any particular problems can be obtained from the viewpoint of storage stability of the aqueous metal composition.

[0073] The aqueous metal composition of the present invention is less likely to produce precipitates and less likely to aggregate even during long-term storage, making it suitable for various applications requiring preservation. In addition to industrial applications (e.g., various industrial products or industrial raw materials such as aqueous pulp, coated paper, paper coating solutions, coatings, adhesives, bonding agents, latexes, inks, etching solutions, immersion water, wood, fibers, wood flour, plastics, cement admixtures, sealants, resin emulsions, and building materials), the aqueous metal composition of the present invention can also be used in various applications, including agricultural fields such as planting and cultivation, where safety is particularly important, food applications such as antibacterial bottles, and physical and chemical materials such as cell culture substrates. The aqueous metal composition of the present invention is particularly useful as an antibacterial agent, an antialgae agent, a biofilm formation inhibitor, and an antiviral agent.

[0074] The method for producing the aqueous metal composition of the present invention is not particularly limited, and for example, a wide range of known methods can be employed. As an example of a method for producing the aqueous metal composition of the present invention, the aqueous metal composition of the present invention can also be produced by mixing a silver precursor and a metal M precursor (hereinafter referred to as "production method A"). Specifically, the silver precursor is a precursor of silver particles or a precursor of silver ions, and the metal M precursor is specifically a precursor of metal M particles or a precursor of metal M ions (also referred to as simply a metal M precursor).

[0075] In manufacturing method A, the silver precursor refers to, for example, a compound containing silver, which can be formed into silver particles or silver ions by chemical treatment. Similarly, the metal M precursor refers to, for example, a compound containing metal M, which can be formed into metal M particles or metal M ions by chemical treatment.

[0076] Examples of silver precursors include silver complexes. Silver complexes can be obtained by complexing a silver source. Examples of silver sources include silver oxides, hydroxides, chlorides, carbonates, acetates, nitrates, oxalates, and phosphates.

[0077] In the present invention, from the viewpoint of adjusting the amount of chlorine contained in the aqueous metal composition to a certain amount or less, the silver source preferably includes a compound containing no chlorine such as chloride. For example, the silver source preferably includes at least silver nitrate.

[0078] When a chlorine-containing compound such as chloride is used as the silver source, its usage amount needs to be adjusted so that the Cl / Ag ratio of the resulting aqueous metal composition satisfies 0.05 or less. For example, when chloride is used as the silver source, the chlorine content in the resulting aqueous metal composition can be adjusted to a predetermined range by using it in combination with a chlorine-free silver source.

[0079] The method for complexing the silver source is not particularly limited, and can be performed, for example, by reacting the silver source with an organic salt. Trisodium citrate or sodium acetate is preferably used as the organic salt. Trisodium citrate and sodium acetate may be hydrates. Complexing the silver source can be performed, for example, in water.

[0080] When the silver source is complexed, the ratio of the silver source to the organic salt is not particularly limited. For example, the silver source can be complexed with 2 or more moles of the organic salt relative to 1 mole of silver contained in the silver source.

[0081] Examples of the precursor of the metal M include complexes of the metal M. The complex of the metal M can be obtained, for example, by complexing a source of the metal M. Examples of the source of metal M include oxides, hydroxides, chlorides, carbonates, acetates, nitrates, diamine dinitro compounds, oxalates, phosphates, ammonium salts, sulfates, and sulfites of the metal M.

[0082] In the present invention, from the perspective of regulating the amount of chlorine contained in the aqueous metal composition to a certain amount or less, the M source preferably includes a compound that does not contain chlorine such as chloride. For example, the M source preferably includes at least a diammine-dinitro compound of metal M. An example of a diammine-dinitro compound of metal M is dinitrodiammineplatinum(II) (Pt(NO2)2(NH3)2).

[0083] When using a chlorine-containing compound such as chloride as the M source, its usage amount needs to be adjusted so that the Cl / Ag ratio of the resulting aqueous metal composition is 0.05 or less. For example, when using chloride as the M source, in contrast, by using it in combination with a chlorine-free M source, the chlorine content in the resulting aqueous metal composition can be adjusted to a predetermined range.

[0084] The method for complexing the M source is not particularly limited, and can be carried out, for example, by reacting the M source with an organic salt. As the organic salt, trisodium citrate is preferably used. Trisodium citrate can be a hydrate. Complexing the M source can be carried out, for example, in water.

[0085] When the M source is complexed, the ratio of the M source to the organic salt is not particularly limited. For example, the M source can be complexed with 2 or more moles of the organic salt per 1 mole of the metal M contained in the M source.

[0086] In production method A, the method for mixing the silver precursor and the precursor of metal M is not particularly limited. For example, a method of mixing a solution of the silver precursor in the above-mentioned aqueous solvent (e.g., an aqueous solution) with a solution of the metal M precursor in the above-mentioned aqueous solvent (e.g., an aqueous solution) can be mentioned. When performing this mixing, the temperature during mixing is also not particularly limited and can be, for example, room temperature, specifically, 15 to 35°C.

[0087] In Production Method A, after the silver precursor and the metal M precursor are mixed to obtain a mixed solution, an acid may be further added to the mixed solution. The addition of the acid appropriately adjusts the pH of the mixed solution, thereby promoting particle formation, thereby easily and quickly obtaining a dispersion containing the aforementioned silver particles and metal M particles. Examples of the acid include inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid; and organic acids such as acetic acid, citric acid, and succinic acid. Among these, organic acids are preferably used, with citric acid being particularly preferred, due to their excellent dispersion stability of the generated particles.

[0088] Alternatively, after the silver precursor and the metal M precursor are mixed to form a mixed solution, the mixed solution may be further heated. By appropriately adjusting the heating temperature during this heating, particle formation is promoted, allowing a dispersion containing the aforementioned silver particles and metal M particles to be easily and quickly obtained. Therefore, when producing an aqueous metal composition as a metal particle dispersion, it is more preferable to further heat the mixed solution after the silver precursor and the metal M precursor are mixed to form a mixed solution. To facilitate the reaction, the heating temperature is preferably 40°C or higher, more preferably 45°C or higher, and particularly preferably 50°C or higher. To facilitate particle size control, the heating temperature is preferably 100°C or lower, more preferably 98°C or lower, and particularly preferably 95°C or lower.

[0089] It should be noted that the above-mentioned heating does not need to be performed when producing an aqueous metal composition as a metal ion solution.

[0090] After obtaining the aqueous metal composition by the above-described production method A, the concentrations of silver and metal M can be adjusted to a desired range by mixing an aqueous medium as needed.

[0091] In Production Method A, for example, the Cl / Ag ratio can be adjusted to 0.05 or less based on the amounts of chlorine and silver contained in the raw materials used. Specifically, by calculating the amounts of chlorine and silver in each raw material used to produce the aqueous metal composition of the present invention, and using each raw material in an amount that achieves a Cl / Ag ratio of 0.05 or less, the target aqueous metal composition can be produced. As described above, the target aqueous metal composition can also be produced by methods such as removing chlorine from the aqueous metal composition, adding chlorine, or adding silver.

[0092] The method for producing the aqueous metal composition is not limited to the above-described production method A, and other production methods may be used. For example, the aqueous metal composition can be produced by separately producing silver particles and metal M particles and mixing them, or by separately preparing commercially available silver particles and metal M particles and mixing them.

[0093] In determining the inventions included in this application, the various structures (properties, structures, functions, etc.) described in the various embodiments of this application can be arbitrarily combined. That is, in this application, all themes consisting of all combinations of the various structures that can be combined described in this specification are included.

[0094] [Example]

[0095] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0096] (Manufacturing Example 1-1; Silver Precursor)

[0097] 0.104 g of silver nitrate and 0.15 g of trisodium citrate dihydrate were dissolved in 100 mL of ion-exchanged water (25°C) and stirred for 30 minutes to prepare an aqueous solution containing a silver complex. The resulting aqueous solution containing the silver complex was used as an aqueous solution containing a silver precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and was found to be below the detection limit. The silver concentration in this aqueous solution was measured by ICP-MS and was found to be 660 ppm by mass.

[0098] (Manufacturing Example 1-2; Silver Precursor)

[0099] 0.788 g of silver nitrate and 0.3 g of trisodium citrate dihydrate were dissolved in 100 mL of ion-exchanged water (25°C) and stirred for 30 minutes to prepare an aqueous solution containing a silver complex. The resulting aqueous solution containing the silver complex was used as an aqueous solution containing a silver precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and was found to be below the detection limit. The silver concentration in this aqueous solution was measured by ICP-MS and was found to be 5000 ppm by mass.

[0100] (Production Example 2-1; Platinum Precursor)

[0101] 0.3 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.027 g of dinitrodiammineplatinum(II) and 0.178 g of potassium chloroplatinate(II) (K2PtCl4), and stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and the result was 594 mass ppm.

[0102] (Manufacturing Example 2-2; Platinum Precursor)

[0103] 0.3 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.119 g of dinitrodiammineplatinum(II) and 0.059 g of potassium chloroplatinate(II), and stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and was found to be 198 mass ppm.

[0104] (Manufacturing Example 2-3; Platinum Precursor)

[0105] 0.3 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.149 g of dinitrodiammineplatinum(II) and 0.020 g of potassium chloroplatinate(II), and stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and was found to be 66 mass ppm.

[0106] (Manufacturing Example 2-4; Platinum Precursor)

[0107] 0.15 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.157 g of dinitrodiammineplatinum(II) and 0.010 g of potassium chloroplatinate(II), and stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and was found to be 33 mass ppm.

[0108] (Manufacturing Example 2-5; Platinum Precursor)

[0109] 0.15 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.160 g of dinitrodiammineplatinum(II) and 0.006 g of potassium chloroplatinate(II), and stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and found to be 19.8 mass ppm.

[0110] (Manufacturing Example 2-6; Platinum Precursor)

[0111] 0.15 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.163 g of dinitrodiammineplatinum(II) and 0.002 g of potassium chloroplatinate(II), and stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and found to be 6.6 mass ppm.

[0112] (Manufacturing Example 2-7; Platinum Precursor)

[0113] 0.15 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.165 g of dinitrodiammineplatinum(II), and the mixture was stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and found to be 0 ppm by mass.

[0114] (Manufacturing Example 2-8; Platinum Precursor)

[0115] 2.0 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.318 g of dinitrodiammineplatinum(II) and 0.015 g of potassium chloroplatinate(II), and stirred for 30 minutes to prepare an aqueous solution containing a platinum complex. The aqueous solution containing the platinum complex thus obtained was used as an aqueous solution containing a platinum precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and was found to be 50 mass ppm.

[0116] (Production Example 3-1; Gold Precursor)

[0117] 0.15 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.214 g of sodium gold sulfite and 0.002 g of tetrachloroauric acid (HAuCl4·4H2O), and the mixture was stirred for 30 minutes to prepare an aqueous solution containing a gold complex. The resulting aqueous solution containing the gold complex was used as the aqueous solution containing a gold precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and found to be 6.6 ppm by mass. The gold concentration in this aqueous solution was measured by ICP-MS and found to be 1000 ppm by mass.

[0118] (Production Example 4-1; Zinc Precursor)

[0119] 0.15 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.413 g of zinc sulfate heptahydrate (ZnSO2·7H2O) and 0.013 g of zinc chloride (ZnCl2), and the mixture was stirred for 30 minutes to prepare an aqueous solution containing a zinc complex. The aqueous solution containing the zinc complex thus obtained was used as an aqueous solution containing a zinc precursor. Ion chromatography measured the chlorine concentration in this aqueous solution and found it to be 66 ppm by mass. ICP-MS measured the zinc concentration in this aqueous solution and found it to be 1000 ppm by mass.

[0120] (Manufacturing Example 4-2; zinc precursor)

[0121] 0.15 g of trisodium citrate dihydrate was dissolved in 100 g of an aqueous solution containing 0.437 g of zinc sulfate heptahydrate (ZnSO2·7H2O) and 0.001 g of zinc chloride (ZnCl2), and the mixture was stirred for 30 minutes to prepare an aqueous solution containing a zinc complex. The aqueous solution containing the zinc complex thus obtained was used as an aqueous solution containing a zinc precursor. The chlorine concentration in this aqueous solution was measured by ion chromatography and found to be 6.6 ppm by mass. The zinc concentration in this aqueous solution was measured by ICP-MS and found to be 1000 ppm by mass.

[0122] [Metal particles]

[0123] (Example 1a)

[0124] To a prepared solution containing 100 mL of the aqueous solution of the silver precursor obtained in Preparation Example 1-1 and 790 mL of ion-exchanged water, 100 mL of the aqueous solution of the platinum precursor obtained in Preparation Example 2-4 was added dropwise while stirring for 60 minutes to obtain a mixed solution. 0.36 g of citric acid was added to the obtained mixed solution to adjust the pH of the mixed solution to 2-4, and 10 mL of washing water was added. After further stirring for 60 minutes, the mixture was heated at 90°C for 24 hours. Thus, an aqueous dispersion containing silver particles and platinum particles was obtained as an aqueous metal composite. The content of particles in the obtained aqueous metal composite was confirmed by ICP-MS (Elan DRCII manufactured by Pak-Elmer Co., Ltd.), and the result was 100 mass ppm of platinum particles and 66 mass ppm of silver particles. Based on the added amount, the chlorine concentration was calculated to be 3.3 mass ppm. Therefore, the Cl / Ag value was 0.05.

[0125] (Example 2a)

[0126] An aqueous metal composition was obtained using the same method as in Example 1a, except that the aqueous platinum precursor solution obtained in Preparation Example 2-5 was used instead of the aqueous platinum precursor solution obtained in Preparation Example 2-4. The particle content in the resulting aqueous metal composition was confirmed using ICP-MS (Elan DRCII, manufactured by Parkin Elmer). The results showed 100 ppm by mass of platinum particles and 66 ppm by mass of silver particles. The chlorine concentration, calculated based on the added amount, was 1.98 ppm by mass. Therefore, the Cl / Ag ratio was 0.03.

[0127] (Example 3a)

[0128] An aqueous metal composition was obtained using the same method as in Example 1a, except that the aqueous platinum precursor solution obtained in Preparation Example 2-6 was used instead of the aqueous platinum precursor solution obtained in Preparation Example 2-4. The particle content in the resulting aqueous metal composition was confirmed using ICP-MS (Elan DRCII, manufactured by Parkin Elmer Co., Ltd.). The results showed that the platinum particles accounted for 100 ppm by mass and the silver particles accounted for 66 ppm by mass. Based on the added amount, the chlorine concentration was calculated to be 0.66 ppm by mass. Therefore, the Cl / Ag ratio was 0.01.

[0129] (Example 4a)

[0130] An aqueous metal composition was obtained using the same method as in Example 1a, except that the aqueous platinum precursor solution obtained in Preparation Example 2-7 was used instead of the aqueous platinum precursor solution obtained in Preparation Example 2-4. The particle content in the resulting aqueous metal composition was confirmed using ICP-MS (Elan DRCII, manufactured by Pak-Elmer Co., Ltd.). The results showed that the platinum particles accounted for 100 ppm by mass and the silver particles accounted for 66 ppm by mass. The chlorine concentration calculated based on the added amount was 0 ppm by mass. Therefore, the Cl / Ag ratio was 0.

[0131] (Example 5a)

[0132] To a prepared solution containing 100 mL of the aqueous solution of the silver precursor obtained in Manufacturing Example 1-2 and 790 mL of ion-exchanged water, 100 mL of the aqueous solution of the platinum precursor obtained in Manufacturing Example 2-8 was added dropwise while stirring for 60 minutes to obtain a mixed solution. 2.73 g of citric acid was added to the obtained mixed solution to adjust the pH of the mixed solution to 2-4, and 10 mL of washing water was added. After further stirring for 60 minutes, the mixture was heated at 90°C for 24 hours. Thus, an aqueous dispersion containing silver particles and platinum particles was obtained as an aqueous metal composition. The ion content in the obtained aqueous metal composition was confirmed by ICP-MS (Elan DRCII manufactured by Pak-Elmer Co., Ltd.), and the result was 200 mass ppm for platinum particles and 500 mass ppm for silver particles. Based on the added amount, the chlorine concentration was calculated to be 5 mass ppm. Therefore, the Cl / Ag value was 0.01.

[0133] (Example 6a)

[0134] To a prepared solution containing 100 mL of the aqueous silver precursor solution obtained in Preparation Example 1-1 and 790 mL of ion-exchanged water, 100 mL of the aqueous gold precursor solution obtained in Preparation Example 3-1 was added dropwise while stirring over 60 minutes to obtain a mixed solution. To the resulting mixed solution, 0.36 g of citric acid was added to adjust the pH of the mixed solution to 2-4. 10 mL of washing water was added, and after further stirring for 60 minutes, the mixture was heated at 90°C for 24 hours. This yielded an aqueous dispersion containing silver and gold particles as an aqueous metal composite. The particle content in the resulting aqueous metal composite was confirmed using ICP-MS (Elan DRCII, manufactured by Perkin Elmer Co., Ltd.), revealing 100 ppm by mass of gold particles and 66 ppm by mass of silver particles. Based on the added amount, the chlorine concentration was calculated to be 0.66 ppm by mass. Therefore, the Cl / Ag ratio was 0.01.

[0135] (Comparative Example 1a)

[0136] An aqueous metal composition was obtained using the same method as in Example 1a, except that the aqueous platinum precursor solution obtained in Preparation Example 2-1 was used instead of the aqueous platinum precursor solution obtained in Preparation Example 2-4. The particle content in the resulting aqueous metal composition was confirmed using ICP-MS (Elan DRCII, manufactured by Parkin Elmer Co., Ltd.). The results showed 100 ppm by mass of platinum particles and 66 ppm by mass of silver particles. The chlorine concentration, calculated based on the added amount, was 59.4 ppm by mass. Therefore, the Cl / Ag ratio was 0.9.

[0137] (Comparative Example 2a)

[0138] An aqueous metal composition was obtained using the same method as in Example 1a, except that the aqueous platinum precursor solution obtained in Preparation Example 2-2 was used instead of the aqueous platinum precursor solution obtained in Preparation Example 2-4. The content of particles in the aqueous metal composition relative to the aqueous medium was confirmed by ICP-MS (Elan DRCII, manufactured by Pak-Elmer Co., Ltd.). The results showed that the platinum particles accounted for 100 mass ppm and the silver particles accounted for 66 mass ppm. Based on the added amount, the chlorine concentration was calculated to be 19.8 mass ppm. Therefore, the Cl / Ag ratio was 0.3.

[0139] (Comparative Example 3a)

[0140] An aqueous metal composition was obtained using the same method as in Example 1a, except that the aqueous platinum precursor solution obtained in Preparation Example 2-3 was used instead of the aqueous platinum precursor solution obtained in Preparation Example 2-4. The particle content in the resulting aqueous metal composition was confirmed using ICP-MS (Elan DRCII, manufactured by Parkin Elmer Co., Ltd.). The results showed 100 ppm by mass of platinum particles and 66 ppm by mass of silver particles. Based on the added amount, the chlorine concentration was calculated to be 6.6 ppm by mass. Therefore, the Cl / Ag ratio was 0.1.

[0141] [Metal ions]

[0142] (Example 1b)

[0143] To a prepared solution containing 100 mL of the aqueous solution of the silver precursor obtained in Manufacturing Example 1-1 and 790 mL of ion-exchanged water, 100 mL of the aqueous solution of the platinum precursor obtained in Manufacturing Example 2-6 was added dropwise while stirring for 60 minutes to obtain a mixed solution. 0.36 g of citric acid was added to the obtained mixed solution to adjust the pH of the mixed solution to 2-4, 10 mL of washing water was added, and the mixture was further stirred for 60 minutes to obtain an aqueous solution containing silver ions and platinum ions as an aqueous metal composition. The content of ions in the obtained aqueous metal composition was confirmed by ICP-MS (Elan DRCII manufactured by PerkinElmer Co., Ltd.), and the result was that the platinum ions were 100 mass ppm and the silver ions were 66 mass ppm. Based on the amount added, the chlorine concentration was calculated to be 0.66 mass ppm. Therefore, the Cl / Ag value was 0.01.

[0144] (Example 2b)

[0145] To a prepared solution containing 100 mL of the aqueous solution of the silver precursor obtained in Manufacturing Example 1-2 and 790 mL of ion-exchanged water, 100 mL of the aqueous solution of the platinum precursor obtained in Manufacturing Example 2-8 was added dropwise while stirring for 60 minutes to obtain a mixed solution. 2.73 g of citric acid was added to the obtained mixed solution to adjust the pH of the mixed solution to 2-4, and 10 mL of washing water was added, and the mixture was further stirred for 60 minutes to obtain an aqueous solution containing silver ions and platinum ions as an aqueous metal composition. The content of ions in the obtained aqueous metal composition was confirmed by ICP-MS (Elan DRCII manufactured by PerkinElmer Co., Ltd.), and the result was 200 mass ppm of platinum ions and 500 mass ppm of silver ions. Based on the amount added, the concentration of chlorine was calculated to be 5 mass ppm. Therefore, the value of Cl / Ag was 0.01.

[0146] (Comparative Example 1b)

[0147] To a prepared solution containing 100 mL of the aqueous solution of the silver precursor obtained in Manufacturing Example 1-1 and 790 mL of ion-exchanged water, 100 mL of the aqueous solution of the platinum precursor obtained in Manufacturing Example 2-2 was added dropwise while stirring for 60 minutes to obtain a mixed solution. 0.36 g of citric acid was added to the obtained mixed solution to adjust the pH of the mixed solution to 2-4, and 10 mL of washing water was added, and the mixture was further stirred for 60 minutes to obtain an aqueous solution containing silver ions and platinum ions as an aqueous metal composition. The content of ions in the obtained aqueous metal composition was confirmed by ICP-MS (Elan DRCII manufactured by Pakin Elmer Co., Ltd.), and the result was 100 mass ppm of platinum ions and 66 mass ppm of silver ions. Based on the amount added, the chlorine concentration was calculated to be 19.8 mass ppm. Therefore, the Cl / Ag value was 0.3.

[0148] (Example 3b)

[0149] To a prepared solution containing 100 mL of the aqueous solution of the silver precursor obtained in Production Example 1-1 and 790 mL of ion-exchanged water, 100 mL of the aqueous solution of the gold precursor obtained in Production Example 3-1 was added dropwise while stirring for 60 minutes to obtain a mixed solution. To the resulting mixed solution, 0.36 g of citric acid was added to adjust the pH of the mixed solution to 2-4. 10 mL of washing water was added, and the mixture was further stirred for 60 minutes to obtain an aqueous solution containing silver ions and gold ions as an aqueous metal composition. The ion content in the resulting aqueous metal composition was confirmed using ICP-MS (Elan DRCII manufactured by Perkin Elmer Co., Ltd.), and the results showed that the gold ion content was 100 mass ppm and the silver ion content was 66 mass ppm. Based on the added amount, the chlorine concentration was calculated to be 0.66 mass ppm. Therefore, the Cl / Ag value was 0.01.

[0150] (Example 4b)

[0151] To a prepared solution containing 100 mL of the aqueous solution of the silver precursor obtained in Manufacturing Example 1-1 and 790 mL of ion-exchanged water, 100 mL of the aqueous solution of the zinc precursor obtained in Manufacturing Example 4-2 was added dropwise while stirring for 60 minutes to obtain a mixed solution. 0.36 g of citric acid was added to the obtained mixed solution to adjust the pH of the mixed solution to 2-4, and 10 mL of washing water was added, followed by further stirring for 60 minutes to obtain an aqueous solution containing silver ions and zinc ions as an aqueous metal composition. The ion content in the obtained aqueous metal composition was confirmed by ICP-MS (Elan DRCII manufactured by PerkinElmer Co., Ltd.), and the result was 100 mass ppm of zinc ions and 66 mass ppm of silver ions. Based on the amount added, the chlorine concentration was calculated to be 0.66 mass ppm. Therefore, the Cl / Ag value was 0.01.

[0152] (Comparative Example 2b)

[0153] An aqueous metal composition was obtained using the same method as in Example 1a, except that the aqueous zinc precursor solution obtained in Preparation Example 4-1 was used instead of the aqueous zinc precursor solution obtained in Preparation Example 4-2. The particle content in the resulting aqueous metal composition was confirmed using ICP-MS (Elan DRCII, manufactured by Perkin Elmer Co., Ltd.). The results showed 100 ppm by mass of zinc ions and 66 ppm by mass of silver ions. Based on the added amount, the chlorine concentration was calculated to be 6.6 ppm by mass. Therefore, the Cl / Ag ratio was 0.1.

[0154] [Evaluation method]

[0155] The aqueous metal compositions obtained in each example and comparative example were stored under the following storage conditions, and then visually observed to determine whether a precipitate was observed. The observation of a precipitate was considered "yes", and the absence of a precipitate was considered "no".

[0156] Storage Conditions

[0157] 100 mL of the aqueous metal composition was sealed in a 110 mL container in an air atmosphere, and the container was placed in a thermostatic bath maintained at 40° C. for storage for 3 weeks and 6 weeks.

[0158] (Evaluation Results)

[0159] Tables 1, 2, 3, 4, and 5 show the blending conditions and Cl / Ag ratios of the aqueous metal compositions produced in each of the Examples and Comparative Examples, as well as evaluation results before and after the aforementioned storage conditions. The "particle size Dn50" in Tables 1 and 3 is the average primary particle size of the aqueous metal composition, as measured using a zeta potential analyzer (Zeta Sensor Nano ZS90, manufactured by Malvern). Note that the aqueous metal compositions of Comparative Examples 1a, 2a, and 3a exhibited significant aggregation, making accurate particle size determination difficult; therefore, these values are indicated as "not measured."

[0160] As shown in Tables 1 and 2, the aqueous metal compositions obtained in the Examples showed no precipitation and were particularly resistant to agglomeration even during long-term storage. Therefore, it was confirmed that aqueous metal compositions containing a metal M (platinum, gold, or zinc) content of 0.1 mass ppm to 100,000 mass ppm relative to the aqueous medium and a chlorine to silver mass ratio (Cl / Ag) of 0.05 or less suppressed precipitation and were less likely to agglomerate even during long-term storage. In particular, aqueous metal compositions with a Cl / Ag ratio of less than 0.05 (specifically, less than 0.03) showed no precipitation after not only three weeks but also six weeks of storage, demonstrating remarkably excellent stability.

[0161] [Table 1]

[0162]

[0163] [Table 2]

[0164]

[0165] [Table 3]

[0166]

[0167] [Table 4]

[0168]

[0169] [Table 5]

[0170]

Claims

1. A water-based metal composition, characterized in that comprising an aqueous medium, silver, and at least one metal M other than silver, The metal M is a metal having antibacterial and / or antiviral properties, The content ratio of the metal M relative to the aqueous medium is 0.1 mass ppm or more and 100,000 mass ppm or less, The mass ratio of chlorine to silver is 0.05 or less.

2. The aqueous metal composition according to claim 1, wherein The silver and the metal M are in granular form.

3. The aqueous metal composition according to claim 1, wherein The silver and the metal M are ions.

4. The aqueous metal composition according to any one of claims 1 to 3, wherein The metal M is at least one selected from the group consisting of platinum, gold, copper, zinc, nickel, and aluminum.

5. The aqueous metal composition according to any one of claims 1 to 3, wherein The metal M is at least one selected from the group consisting of platinum, gold, copper, and zinc.

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