Metal film forming material and method for manufacturing the same

Abstract

The present invention provides a metal film-forming material and a method for producing the same, which can exhibit excellent ammonia adsorption effects and increase the amount of metal ions eluted into the solvent. [Solution] A metal film forming material comprising a metal precursor liquid having a reaction product of at least one selected from the group consisting of metal complexes and metal salts and at least one selected from ammonia and amine, and an organic reducing agent, wherein a substrate is immersed in the composition for forming a metal film and then dried to form a metal film on the surface of the substrate, wherein the ammonia concentration after 5 minutes when 15 mg of the metal film forming material is added to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm is 1 / 3 or less of the ammonia concentration after 5 minutes when 15 mg of the substrate is added to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm.

Description

Technical Field

[0001] The present invention relates to a metal film piece forming material formed by forming metal film pieces on the surface of a substrate and a method for manufacturing the same.

Background Art

[0002] Generally, as methods for forming a metal film on the surface of a substrate, those by vapor phase methods such as sputtering and chemical vapor deposition, and those by liquid phase methods such as electrolytic plating and electroless plating are known. However, in the case of vapor phase methods, large-scale equipment is required for film formation, or the size of the substrate to be film-formed is restricted, and in the case of liquid phase methods, heat treatment for crystal improvement is required.

[0003] Therefore, conventionally, a method for forming a metal film by a molecular precursor method in which a metal complex solution is applied to a substrate and processed by light energy or heat energy to obtain a metal oxide film has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the case of the above conventional metal film forming method, for example, a copper metal film is formed on various substrates, which generally improves well-known antibacterial properties, and technologies that can exhibit other performances have not been established.

[0006] As a result of diligent research, the inventors have confirmed that by constructing a metal film fragment molding material in which a metal film is formed on the surface of a substrate, an excellent ammonia adsorption effect can be achieved, and the amount of metal ions eluted into the solvent can be increased. [Means for solving the problem]

[0007] The present invention provides a metal film forming material for solving the above problems, comprising a metal precursor liquid having a reaction product of at least one selected from the group consisting of metal complexes and metal salts and at least one selected from ammonia and amine, and an organic reducing agent, wherein a substrate is immersed in the metal film forming composition, and then dried to form a metal film on the surface of the substrate, and the ammonia concentration after 5 minutes when 15 mg of the metal film forming material is added to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm is 1 / 3 or less of the ammonia concentration after 5 minutes when 15 mg of the substrate is added to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm.

[0008] The present invention provides a metal film-forming material for solving the above problems, comprising a metal precursor solution containing a reaction product of at least one selected from the group consisting of metal complexes and metal salts and at least one selected from ammonia and amine, and an organic reducing agent, wherein a substrate is immersed in this composition and then dried to form a metal film on the surface of the substrate. The present invention provides a metal film-forming material in which 0.1 g of the metal film-forming material is placed in 10 ml of tap water, left to stand for 30 minutes, and then centrifuged at 10,000 rpm for 5 minutes, and the metal ion concentration in the solution is at least twice the metal ion concentration in the solution obtained by placing 0.1 g of metal powder in 10 ml of tap water, leaving to stand for 30 minutes, and then centrifuging at 10,000 rpm for 5 minutes.

[0009] The above-mentioned metal film forming material may be one in which at least one metal selected from the group consisting of metal complexes and metal salts is copper (Cu).

[0010] The above metal film forming material has a substrate with a specific surface area of ​​300 m². 2 It may also be made of porous material with a weight of 1 / g or more.

[0011] The above-mentioned metal film forming material may have activated carbon as its base material.

[0012] The present invention provides a method for producing a metal film-forming material to solve the above problems, comprising: a metal precursor solution having a reaction product of at least one selected from the group consisting of metal complexes and metal salts and at least one selected from ammonia and amines; and an organic reducing agent, to which a substrate is placed, immersed for 24 hours while stirring, and then dried at 70°C for 24 hours.

[0013] [Metal precursor liquid] The above metal precursor solution is obtained by reacting at least one selected from the group consisting of metal complexes and metal salts with at least one selected from ammonia and amines in a mixture of a solvent.

[0014] [At least one selected from the group consisting of metal complexes and metal salts] The at least one selected from the group consisting of the above-mentioned metal complexes and metal salts may be one or more types of metal complexes, one or more types of metal salts, or a mixture containing both one or more types of metal complexes and one or more types of metal salts.

[0015] The above metal complex is preferably a reaction product of a metal ion with one or more compounds for metal complex formation selected from compounds having a diamine-derived ligand such as an NH3 ligand, RNH2 ligand (where R represents an alkylene group), OH2 ligand, ethylenediamine, or hexamethylenediamine as a substructure. The metal complex can be a metal complex that has been previously formed by the above reaction. The metal in the metal complex can be a metal that is suitable for the purpose of the metal film to be formed. Examples of metals include silver (Ag), copper (Cu), lithium (Li), nickel (Ni), manganese (Mn), zinc (Zn), and cobalt (Co). Specifically, examples of metal complexes that contain copper (Cu) as the metal include copper ethylenediaminetetraacetate and tetraamminecopper. From the viewpoint of good electrical and thermal conductivity of the formed metal film, Cu and Ag are preferred, and Cu is more preferred.

[0016] The above-mentioned metal salt is a metal compound that has the function of dissociating in a water-containing solvent to become a metal ion and form a metal complex. The above-mentioned metal salt refers to a metal salt that is soluble in water at 25°C. Soluble in water at 25°C means that the solubility in water at 25°C is 0.1% by mass or more, and preferably 1% by mass or more. Because the metal salt is soluble in water, the metal salt dissociates in a water-containing solvent to become a metal ion, and this metal ion reacts with amines contained in the solvent to obtain a metal complex. Furthermore, if the solvent optionally contains a compound for complex formation described later, the metal ion and the compound for complex formation may react to form a metal complex. Specific examples of this metal salt include, for example, copper formate tetrahydrate and copper acetate tetrahydrate when the metal is copper (Cu).

[0017] [At least one selected from ammonia and amines] The at least one selected from the above ammonia and amines may be one or more types of ammonia, one or more types of amines, or a mixture containing both one or more types of ammonia and one or more types of amines. These may be included as salt compounds. The amines include primary amines, secondary amines, and tertiary amines. Specific examples of amines include alkylamines. Ammonia may be included in place of or in addition to amines. Various types of ammonia that are basic, similar to amines, can be used.

[0018] [solvent] The solvent is not particularly limited as long as it can dissolve at least one selected from the group consisting of the metal complexes and metal salts described above, and the ammonia and amine described above. For example, an aqueous solvent such as water or a mixture of water and alcohol can be used. The water is preferably low in impurities, especially ions other than metal ions, and from that viewpoint, purified water, ion-exchanged water, or pure water is preferred. Examples of alcohols include monohydric alcohols having 1 to 10 carbon atoms such as methanol, ethanol, isopropanol, n-propanol, isobutanol, and n-butanol, and polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, and glycerin.

[0019] From the viewpoint of solubility and handling, water or a mixture of water and a monohydric alcohol having 1 to 5 carbon atoms is preferred as the aqueous solvent, water or a mixture of water and an alcohol selected from methanol, ethanol, and propanol is more preferred, and water is even more preferred. When a mixture of water and alcohol is used as the solvent, the mixing ratio is appropriately selected depending on the purpose. When a mixture of water and alcohol is used as the solvent, the alcohol content relative to the total amount of the water-alcohol mixture is preferably 1% to 60% by mass.

[0020] [Preparation of Metal Precursor Solution] The above metal precursor solution can be prepared by adding at least one selected from the group consisting of the above metal complex and metal salt and at least one selected from the above ammonia and amine to a solvent, and sufficiently stirring and mixing them.

[0021] The mixing may be carried out at room temperature, or may be carried out by heating the solvent to 40°C to 60°C for the purpose of promoting dissolution. The stirring method is not particularly limited. For example, a method of putting the mixed solution into a container and stirring it using a rotor such as a magnetic stirrer, a method of stirring it with a stirring device equipped with a rotary stirring blade such as a paddle, a method of putting the solution into a container that can be sealed and shaking the container to stir it, a method of irradiating ultrasonic waves, etc., known stirring methods can be applied.

[0022] As a simple method, a method of using a stirring device equipped with a stirring blade can be mentioned. The rotational speed of the rotary blade can be 300 rpm (revolutions per minute; the same applies hereinafter) to 800 rpm, and preferably 400 rpm to 600 rpm. The stirring is preferably carried out until the reaction between at least one selected from the group consisting of the above metal complex and metal salt and the above amine proceeds sufficiently. When stirring with a stirring device equipped with a rotary blade at room temperature as described above, it is preferably stirred for about 30 minutes to 90 minutes, and more preferably stirred for about 50 minutes to 80 minutes.

[0023] The preparation of the above-described composition for forming metal film pieces may be obtained by applying a known molecular precursor method. Further, although the preparation of the composition for forming metal film pieces can apply a known precursor method as described above, from the viewpoint of obtaining a composition for forming metal film pieces with higher purity, it preferably includes the following electrolysis step. That is, in a reaction apparatus provided with a pair of electrolytic solution tanks connected via a flow path equipped with a filter that allows hydrogen ions to permeate but not metal ions, an electrolytic solution containing an amine is stored in each of the pair of electrolytic solution tanks, and a pair of metal electrodes are arranged at positions where at least a part thereof contacts this electrolytic solution, and a step of connecting between this pair of electrodes via a DC power supply, and a step of applying a voltage between the pair of electrodes by a DC power supply to react metal ions derived from the metal as the electrode with the electrolytic solution in the electrolytic solution tank in which the electrode serving as the anode (anode) is immersed to obtain a composition for forming metal film pieces.

[0024] [Preparation of Metal Precursor Liquid] The above metal precursor liquid can be prepared by containing at least one selected from the group consisting of the above-described metal complex and metal salt and at least one selected from the above-described ammonia and amine in a solvent and sufficiently stirring and mixing them. The composition for forming metal film pieces is obtained by mixing a metal precursor liquid and an organic reducing agent. At this time, the mixing ratio of the metal precursor liquid and the organic reducing agent is not particularly limited and can be appropriately selected according to the target metal. With respect to 100 parts by mass of the organic reducing agent contained in the composition for forming metal film pieces, the metal ions contained in the metal precursor liquid can be 50 parts by mass to 400 parts by mass. Among them, from the viewpoint that the formability of the metal film pieces of the obtained composition for forming metal film pieces is better, it is preferable that the metal ions contained in the metal precursor liquid are 100 parts by mass to 350 parts by mass with respect to 100 parts by mass of the organic reducing agent, and it is more preferable that the metal ions contained in the metal precursor liquid are 150 parts by mass to 350 parts by mass with respect to 100 parts by mass of the organic reducing agent.

[0025] By setting the content of metal ions in the organic reducing agent to the above-mentioned preferred range, metal film fragments can be formed more efficiently on the surface of the substrate. If the mixing ratio of metal precursor solution to 100 parts by mass of organic reducing agent is less than 50 parts by mass, metal deposition becomes difficult to occur quickly, and if it exceeds 400 parts by mass, the reducing power of the metal ions becomes insufficient. The content of the metal precursor solution in the preparation of the metal film forming composition can be controlled by adjusting the type and content of the metal complex when preparing the metal precursor solution, or by adjusting the type of electrolyte, the concentration of the electrolyte, the applied energy of the DC current, and the application time during the electrolysis step when preparing the metal precursor solution. Generally, it is difficult to measure the content of a specific metal compound relative to the total amount of a metal film-forming composition. However, the physical properties of the metal film formed by the metal film-forming composition depend on the metal content in the composition. From the viewpoint of forming a stable metal film, the metal content relative to the total amount of the metal film-forming composition is preferably 0.05 mmol / g or more, and more preferably in the range of 0.1 mmol / g to 0.5 mmol / g. When the metal content is within the above range, the structure of the metal film formed by the metal film-forming composition becomes more uniform, and a stable metal film can be formed.

[0026] The metal content in a composition for forming metal film fragments can be measured, for example, by the method described in "Fundamentals of Coordination Chemistry: Werner Complexes and Organometallic Complexes" (KS Chemistry Textbook: Kodansha, 1989).

[0027] The content of a specific reducing agent in a metal film-forming composition can be measured, for example, by the following method. First, the metal film-forming composition is dried to produce a powder. The content of the specific reducing agent can then be measured by analyzing the obtained powder using a thermogravimeter-differential thermal analyzer (TG-DTA).

[0028] The pH of the metal film-forming composition at room temperature (25°C) is preferably 6 to 8, and more preferably in the neutral range around pH 7.5. The pH can be measured using a known pH meter.

[0029] [Base material] The substrate is not particularly limited as long as it can form a metal film using the metal film forming composition. It may be made of inorganic materials such as glass, metal, or ceramics; natural materials such as wood or plant fibers; synthetic materials such as plastic or synthetic fibers; porous materials such as activated carbon; porous coordination polymers (PCP) / metal-organic structures (MOFs); porous materials obtained by carbonizing these after formation; or composite materials thereof. Furthermore, the substrate may be a hard material such as a glass plate or metal plate; or a flexible or bendable material such as a film, sheet, paper, thread, woven fabric, or nonwoven fabric. In addition, the substrate may be formed in a planar shape such as a plate or sheet; in a linear shape such as a thread or rod; in a three-dimensional shape such as a thick nonwoven fabric or HEPA filter; or in powder or granular form. If the substrate is a porous material, the specific surface area of ​​the porous material is 300 m². 2 It is preferable that the amount is 1 / g or more. Specific porous materials may include porous materials such as activated carbon, porous coordination polymers (PCPs) / metal-organic frameworks (MOFs), or porous materials obtained by carbonizing these after formation. Alternatively, porous inorganic materials such as zeolites, pumice, and silica gel may also be used. The porous material may be used in powder or granular form, or molded into various shapes. A porous material refers to a material in which microporous (2 nm or less), mesoporous (2-50 nm), and macroporous (50 nm or more) voids are formed within the substrate.

[0030] [Manufacturing of metal film forming components] To manufacture the above-mentioned metal film fragment forming member, first, the substrate is immersed in the above-mentioned metal film fragment forming composition and dried to adhere the metal film fragment to the surface of the substrate. In this case, it is preferable to adhere the substrate to the metal film fragment forming composition by immersing it in the composition. In this case, the immersion time of the substrate is preferably 6 hours or more, and more preferably 12 hours or more, at room temperature (25°C). If a thicker film is desired, the immersion time or storage time can be 24 hours or more.

[0031] There is no particular upper limit on the immersion time, but from the viewpoint of productivity, it can be 120 hours or less, and preferably 90 hours or less. In this case, by setting the temperature of the metal film forming composition to above room temperature, for example, 30°C or higher, preferably 40°C or higher, the reaction rate increases, and metal films can be formed in a shorter storage time. From the viewpoint of minimizing the impact on the metal film forming composition, the temperature is preferably 80°C or lower. For example, when the ambient temperature is 35°C, the storage time is preferably 4 hours or more, and more preferably 8 hours or more. The upper limit of the storage time is the same as in the case of room temperature.

[0032] The immersion pressure may be the pressure under normal atmospheric conditions, or it may be under reduced or increased pressure. Furthermore, the substrate may be immersed without degassing any air bubbles trapped in its voids, or it may be immersed after degassing. If degassing is performed, the substrate may be physically agitated, or the immersion pressure may be changed.

[0033] After the metal film-forming composition is applied to the substrate, a drying process is performed for at least 12 hours. Drying can be carried out by conventional methods such as natural drying, heat drying, or forced-air drying. For natural drying, it is sufficient to leave it at room temperature for at least 12 hours. For heat drying, known heating methods can be appropriately selected and applied. Examples of heating methods include contacting the substrate with a heating means such as a plate heater or heat roll, passing it through a heating zone such as an electric furnace, irradiating it with energy rays such as infrared rays or microwaves, or blowing hot air. There are no particular restrictions on the heating temperature during heat drying, but considering the formation of a metal film, the heating temperature can be in the range of 30°C to less than 80°C, and is preferably in the range of 30°C to 70°C, taking into account drying efficiency and minimizing the impact on the substrate. The drying time during heat drying is not particularly limited as long as it is at least 12 hours, but since drying for longer than 12 hours is not very meaningful, it is preferably between 12 and 24 hours. When using forced air drying, it may be done by blowing air under ambient conditions, or it may be done by blowing hot air as described above.

[0034] When the metal film-forming composition is applied and dried, the solvent contained in the metal film-forming composition evaporates, and the metal film adheres to the substrate. At this time, the amount of metal film that adheres can be adjusted by the immersion concentration during the immersion treatment of the metal film-forming composition.

[0035] The metal film forming material of the present invention, constructed in this manner, allows for the attachment of a metal film forming composition to a substrate, followed by drying to fix metal film fragments to the substrate. This metal film forming material exhibits extremely high adsorption performance for ammonia. Therefore, it can be used as a material for removing harmful gases emitted from various transportation equipment such as automobiles and factories, or as an adsorbent for the storage and transportation of ammonia.

[0036] Furthermore, when this metal film-forming material is added to a liquid, the concentration of metal ions eluted from the material into the liquid can be increased. Therefore, by utilizing the antibacterial and antiviral functions of this high-concentration metal ion-eluted water, it is possible to construct cleaning devices for water-related areas in daily life, or to use this metal ion-eluted water to prevent secondary infections in water-related areas of medical institutions and to prevent norovirus infections. In addition, by using this metal ion-eluted water with a high concentration of eluted metal ions, or by installing a filter made of this metal film-forming material in the water passage to generate metal ion-eluted water with a high concentration of eluted metal ions, it is possible to prevent crop damage and contamination by repelling slugs, prevent the transmission of infectious diseases by preventing the breeding of mosquito larvae, and prevent blood-sucking injuries. [Effects of the Invention]

[0037] As described above, according to the present invention, when 15 mg of the metal film-forming material is added to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm, the ammonia concentration after 5 minutes can be reduced to 1 / 3 or less of the ammonia concentration after 5 minutes when 15 mg of the substrate is added to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm, thus demonstrating extremely high adsorption performance for ammonia. Furthermore, when 0.1 g of metal film-forming material is placed in 10 ml of tap water, left to stand for 30 minutes, and then centrifuged at 10,000 rpm for 5 minutes, the metal ion concentration in the solution can be made more than twice the metal ion concentration in the solution obtained when 0.1 g of metal powder is placed in 10 ml of tap water, left to stand for 30 minutes, and then centrifuged at 10,000 rpm for 5 minutes, thus increasing the concentration of metal ions eluted from the metal film-forming material into the liquid. [Brief explanation of the drawing]

[0038] [Figure 1] This graph shows the results of a time-dependent adsorption test of ammonia gas using the metal film-forming material according to the present invention and the metal film-forming material according to a comparative example. [Figure 2] This graph shows the difference in the amount of copper ions eluted into water using the metal film forming material according to the present invention and the metal film forming material according to the comparative example. [Modes for carrying out the invention]

[0039] [Example 1, Comparative Examples 1-3] (1. Preparation of copper complex aqueous solution) To 160 parts by mass of pure water, 13.38 parts by mass of copper formate tetrahydrate (a metal salt) and 24.47 parts by mass of 25% ammonia water were added. The mixture was stirred at room temperature at 500 rpm for 1 hour to obtain a metal precursor solution. The resulting metal precursor solution was observed to be deep blue in color.

[0040] (2. Preparation of ascorbic acid aqueous solution) 124 parts by mass of pure water was mixed with 31 parts by mass of ascorbic acid as an organic reducing agent, and the mixture was stirred at room temperature (24.0°C) for 30 minutes to obtain a colorless, transparent aqueous solution of ascorbic acid.

[0041] (3. Preparation of compositions for forming metal film fragments) The metal precursor solution obtained in (1.) and the ascorbic acid aqueous solution obtained in (2.) were both cooled to 2°C, and mixed in a ratio of 127.74 parts by mass of the metal precursor solution to 100 parts by mass of the ascorbic acid aqueous solution. The mixture was stirred at room temperature for 20 minutes to obtain a metal film forming composition. Immediately after mixing, the mixture was dark green, but after continued mixing for 20 minutes, the resulting metal forming composition turned yellow.

[0042] (4. Application of metal film formation composition to substrate) A 12 ml metal film-forming composition is poured into a plastic screw-top bottle, and a substrate with an average particle size of 5 μm and a specific surface area of ​​1600 m² is added thereto. 2 0.27 g of activated carbon (1 / g) was added, and the mixture was stirred at room temperature with a stirring bar at 140 rpm for 24 hours. Subsequently, the obtained liquid was filtered through a membrane filter and dried at 70°C for 24 hours to obtain a 0.47 g metal film-forming material with copper deposited on its surface.

[0043] [Rating of copper] (1. Ammonia adsorption test) One liter of ammonia gas, with an ammonia concentration of 80 ppm in a nitrogen atmosphere, was placed in a one-liter sampling bag. 15 mg of the metal film-forming material according to Example 1, obtained above, was placed in this sampling bag. The ammonia concentration in the sampling bag was measured at predetermined time intervals using a detector tube. The results are shown in Figure 1.

[0044] As Comparative Example 1, the above metal film forming material was subjected to a specific surface area of ​​0.067 m² with an average particle size of 5 μm. 2 The copper powder was changed to a concentration of / g, and otherwise the ammonia concentration in the sampling bag was measured in the same manner as in Example 1 above. The results are shown in Figure 1.

[0045] As Comparative Example 2, the above metal film forming material was subjected to a specific surface area of ​​1600 m² with an average particle size of 5 μm. 2 The activated carbon was changed to a different concentration ( / g), and the ammonia concentration in the sampling bag was measured in the same manner as in Example 1 above. The results are shown in Figure 1.

[0046] As Comparative Example 3, the ammonia concentration in a sampling bag with nothing inside was measured. The results are shown in Figure 1.

[0047] The results shown in Figure 1 confirm that the metal film-forming material according to the present invention exhibits superior ammonia gas adsorption capacity compared to activated carbon and copper powder. The first measurement was started 5 minutes after introduction, and at this point, the ammonia level had already decreased to 10 ppm, which is significantly better than the 70 ppm for copper powder in Comparative Example 1 and the 60 ppm for activated carbon in Comparative Example 2.

[0048] (2. Copper ion elution test) Ten milliliters of tap water were poured into a glass container, and 0.1 g of the metal film-forming material according to Example 1 was added thereto. After standing for 30 minutes, the metal film-forming material was filtered through a membrane filter by centrifugal separation (10,000 rpm for 5 minutes). In this manner, a copper ion eluate was obtained from which copper ions had been eluted. The concentration of copper ions in the copper ion eluate was measured using a UV-Vis spectrophotometer (Shimano Seisakusho Co., Ltd. UV-1280). For the measurement, the UV-Vis spectrophotometer was set to copper (Cu) in its water quality measurement mode, and a solution without eluted copper was placed in a quartz cell and set in the holder for a blank measurement. Next, the sample with eluted copper was drawn into a Pack Test (WAK-Cu) tube, shaken, and reacted with the reagent in the tube. After that, the sample was poured into the quartz cell, set in the holder, and measured (pasocuproine absorbance method). The results are shown in Figure 2.

[0049] For comparison, the metal film forming material was changed to copper powder, and the concentration of copper ions in the copper ion eluate was measured in the same manner as in Example 1. The results are shown in Figure 2.

[0050] The results shown in Figure 2 confirm that the metal film-forming material according to the present invention exhibits superior copper ion dissolution power compared to copper powder. After standing for 30 minutes, a difference of more than 10 times in copper ion dissolution power was observed, with 2.75 ppm for the present invention compared to 0.25 ppm for copper powder.

[0051] Furthermore, the present invention can be implemented in various other forms without departing from its spirit or main features. Therefore, the embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. The scope of the present invention is defined by the claims and is not restricted in any way by the text of the specification. Moreover, any modifications or changes within the claims are all within the scope of the present invention.

Claims

1. A metal film forming material is constructed by immersing a substrate in a metal precursor solution containing a reaction product of at least one selected from the group consisting of metal complexes and metal salts and at least one selected from ammonia and amines, and an organic reducing agent, and then drying the substrate to form a metal film on its surface. When 15 mg of the metal film-forming material was added to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm, the ammonia concentration after 5 minutes was: A metal film forming material characterized in that the ammonia concentration after 5 minutes of adding 15 mg of the base material to 1 liter of nitrogen gas with an ammonia concentration of 80 ppm is 1 / 3 or less.

2. A metal film forming material is constructed by immersing a substrate in a metal precursor solution containing a reaction product of at least one selected from the group consisting of metal complexes and metal salts and at least one selected from ammonia and amines, and an organic reducing agent, and then drying the substrate to form a metal film on its surface. 0.1 g of the metal film-forming material was placed in 10 ml of tap water and allowed to stand for 30 minutes. After centrifuging at 10,000 rpm for 5 minutes, the metal ion concentration in the solution was as follows: A metal film forming material characterized by having a metal ion concentration at more than twice the concentration of metal ions in the solution obtained after adding 0.1 g of metal powder to 10 ml of tap water, letting it stand for 30 minutes, and then centrifuging it at 10,000 rpm for 5 minutes.

3. The metal film forming material according to claim 1 or 2, wherein at least one metal selected from the group consisting of metal complexes and metal salts is copper (Cu).

4. The base material has a specific surface area of ​​300 m². ２ The metal film forming material according to claim 1 or 2, wherein the material is a porous material of 1 g or more.

5. The metal film forming material according to claim 4, wherein the base material is activated carbon.

6. A method for producing a metal film forming material according to claim 1 or 2, A method for producing a metal film-forming material, characterized by adding a substrate to a metal film-forming composition containing a metal precursor liquid having a reaction product of at least one selected from the group consisting of metal complexes and metal salts and at least one selected from ammonia and amines, and an organic reducing agent, immersing the substrate in the composition for forming a metal film for 24 hours while stirring, and then drying it at 70°C for 24 hours.

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