Metal particles and methods for manufacturing the same

Abstract

The present invention provides metal particles and a method for producing the same. The method for producing the metal particles includes a step of obtaining the metal particles by subjecting a metal source-containing oxidizing agent and a reducing agent to an oxidation-reduction reaction in the presence of a first dispersant and a second dispersant, the first dispersant including a first organic solvent having a low molecular weight and at least one type of nanoparticles, and the second dispersant including a second organic solvent having a high molecular weight. The metal particles of the present invention have advantages such as a high shrinkage ratio, a large specific surface area, and a high sphericity, and the production method is simple and efficient.

Description

Technical Field

[0001] The present invention belongs to the field of metallic materials, and specifically relates to metal particles and a method for producing the same. Background Art

[0002] Precious metals mainly refer to eight metallic elements including gold, silver and platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, platinum). Most of these metals have beautiful colors and high chemical stability, and hardly undergo chemical reactions with other chemical substances under normal conditions. Precious metal powder has important applications in the production of solar cell pastes such as electronic devices and conductive adhesives, and silver powder as a conductive filler in particular is currently the most widely used precious metal powder.

[0003] The properties of metal powder include not only particle size, but also morphological structure and internal structure, which play a decisive role in the properties of metal paste. Internally porous metal powder is a new material developed in recent years, which has large specific surface area, low specific gravity and excellent permeability due to small metal powder particles and a large number of internal voids. Hollow metal powder has attracted new attention due to its wide applications in catalysis, electrochemistry, drug delivery and other fields.

[0004] Currently, main production methods for metal particles include biological template method, liquid phase reduction method, chemical vapor deposition method, pyrolysis method, etc. Among them, the template method has a complicated process and high cost; the liquid phase reduction method is expensive; and the liquid phase microwave method has harsh reaction conditions and is difficult for mass production. For example, CN101905330A discloses a method for producing hollow silver produced using Streptococcus thermophilus, and CN101912970A discloses a method for producing spherical porous silver powder by a spray method, but there still exist problems such as harsh reaction conditions, excessive fine powder and non-uniform particle size distribution.

[0005] Therefore, there is still a need for a manufacturing method that can produce metal particles with high porosity, large specific surface area, and excellent sphericity, while maintaining a simple process and low cost. [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to overcome the above-mentioned drawbacks of the prior art and provide a method for manufacturing metal particles. The metal particles have advantages such as a high shrinkage ratio, a large specific surface area, and high sphericity, and moreover, the manufacturing method is simple and efficient. [Means for solving the problem]

[0007] To achieve the above objective, in one embodiment, the present invention includes the step of causing a redox reaction between a metal source-containing oxidizing agent and a reducing agent in the presence of a first dispersant and a second dispersant to obtain the metal particles. The first dispersant comprises a first low molecular weight organic solvent and at least one type of nanoparticle, and The second dispersant provides a method for producing metal particles, comprising a high molecular weight second organic solvent.

[0008] In the manufacturing method according to the present invention, the presence of the first and second dispersants plays an important role in the production of metal particles that have advantages such as a high shrinkage ratio, a large specific surface area, and high sphericity. This is because the low molecular weight organic solvent in the first dispersant effectively coats the nanoparticles, forming coated aggregates. The high molecular weight organic polymer in the second dispersant interlocks well with the coated aggregates, forming a homogeneous phase system, thereby making it difficult for the nanoparticles to aggregate in the one-step oxidation-reduction reaction. More specifically, in the initial stage of the oxidation-reduction reaction, the action of the organic solvent in the first dispersant prevents the metal nanoparticles generated in the initial oxidation-reduction reaction from sticking together to form a metal diaphragm structure. After a few seconds or minutes from the reaction, one-step metal nanoparticles are formed, and voids exist inside the formed metal nanoparticles. Subsequently, the newly generated one-step metal nanoparticles polymerize in the environment of the second dispersant, forming metal particles, and these metal particles contain large voids inside. In the two-step reaction, the high molecular weight organic polymer in the second dispersant forms large voids between the metal nanoparticles during the polymerization process of the metal nanoparticles.

[0009] As described above, the metal source-containing oxidizing agent and reducing agent of the present invention can undergo a redox reaction in the presence of a first dispersant and a second dispersant, and there are no particular limitations on the initial reaction system or the order in which the oxidizing agent and reducing agent are added. For example, the oxidizing agent may be added to the system of the first and second dispersants beforehand, and then the reducing agent may be added and the redox reaction carried out; or the reducing agent may be added to the system of the first and second dispersants beforehand, and then the oxidizing agent may be added and the redox reaction carried out; or the oxidizing agent and reducing agent may be added to the system of the first and second dispersants beforehand and the redox reaction carried out. In other words, the oxidizing agent and reducing agent of the present invention may be mixed with the system of the first and second dispersants independently or simultaneously, but there are no particular limitations. Furthermore, the oxidizing agent and reducing agent may be supplied by a replenishment method.

[0010] The first and second dispersants of the present invention both contain organic solvents, but the molecular weights of the two organic solvents are different; that is, the molecular weight of the organic solvent contained in the second dispersant (i.e., the second organic solvent) is higher than the molecular weight of the organic solvent contained in the first dispersant (i.e., the first organic solvent). In one embodiment of the present invention, the low molecular weight and high molecular weight may be distinguished by a specific molecular weight, for example, 1200 Da. Therefore, in this embodiment, the first organic solvent may be an organic solvent with a molecular weight of 1200 Da (e.g., 1000 Da or less, or 800 Da or less), and the second organic solvent may be an organic solvent with a molecular weight exceeding 1200 Da (e.g., 1500 Da).

[0011] The first and second organic solvents are not particularly limited in type, other than the difference in molecular weight. For example, in one embodiment of the present invention, the first and second organic solvents are each independently at least one selected from organic acids (including, but not limited to, fatty acids), gum arabic, ester-based, ether-based, ether ester-based, ketone-based, amine-based, alcohol-based, pyridine-based, and pyrrolidone-based organic solvents. That is, the first and second organic solvents may be the same or different, and may contain one or more of the above organic solvents.

[0012] More specifically, in one embodiment of the present invention, the first organic solvent is fatty acids and their salts, alkyl sulfates and their salts, alkylbenzenesulfonic acids and their salts, linear alkylbenzenesulfonic acids and their salts, maleic acid and its salts, 1-vinylpyrrolidone, N-vinylpyrrolidone, methylpyrrolidone, polyoxyethylene lauryl ether sulfate triethanolamine, octylamine, ethanol, polyethylene glycol, alkyl sulfate triethanolamine, glycerol, alkyl ether sulfate salts, sorbitol, sorbitan, polysorbate (Tween), sorbitan fatty acid ester (Span), lecithin, polysorbate dialkyldimethylammonium chloride, alkylpyridinium chloride, polyoxyethylene alkyl ether (AE), polyoxyethylene The second organic solvent may be at least one selected from lucylphenyl ether (APE), alkyl carboxybetaine, and sulfobetaine, and the second organic solvent may be at least one selected from gum arabic, formaldehyde condensate of naphthalene sulfonate, polyacrylate, copolymer salt of vinyl compound and carboxylic acid monomer, carboxymethylcellulose, polyvinyl alcohol, polyethylene glycol, partially alkyl ester of polyacrylic acid and / or polyalkylene polyamine, polyethyleneimine and / or aminoalkyl methacrylate copolymer, polyvinylpyrrolidone, polystyrene sulfonic acid, polyacrylic acid, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenyl ether, but is not limited to these.

[0013] Furthermore, the first dispersant of the present invention further comprises at least one nanoparticle, the nanoparticle being at least one selected from organic nanoclusters, nonmetallic oxides, elemental metals, metal oxides, and inorganic metal salts, and preferably the size of the nanoparticle is 0.1 to 90 nm (for example, 0.1 nm, 0.2 nm, 0.5 nm, 1 nm, 2 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 70 nm or 90 nm, 1 to 50 nm, 0.1 to 40 nm, etc.).

[0014] More specifically, in one embodiment of the present invention, the organic nanocluster may be at least one selected from cellulose and organic carbohydrates, the nonmetallic oxide may be at least one selected from oxides of silicon, carbon, and nitrogen (i.e., silicon oxide, carbon oxide, nitrogen oxide), the metal may be at least one selected from gold, silver, platinum, palladium, cobalt, copper, nickel, and zinc, the metal oxide may be at least one selected from oxides of gold, silver, platinum, palladium, cobalt, copper, nickel, and zinc, and the metal inorganic salt may be selected from, but is not limited to, metal sulfates and / or nitrates (e.g., sodium sulfate, ammonium sulfate, potassium sulfate, copper sulfate, iron sulfate, sodium nitrate, potassium nitrate, iron nitrate, or copper nitrate).

[0015] In the metal source-containing oxidizing agent of the present invention, the metal source (usually referring to a metal ion) is reduced to a metal in a redox process. Therefore, the metal source-containing oxidizing agent of the present invention may be any compound containing a metal ion, where the metal includes, but is not limited to, at least one of gold, silver, platinum, palladium, cobalt, copper, nickel, and zinc, or the metal may be, in particular, at least one of noble metals, such as gold, silver, and platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, platinum). For example, in one embodiment of the present invention, the metal source-containing oxidizing agent may be at least one selected from inorganic metal salts, organometallic salts, and metal complexes.

[0016] More specifically, in one embodiment of the present invention, the inorganic salt may be at least one of the following, for example, carbonate, bicarbonate, phosphate, phosphite, hydrogen phosphate, nitrate, nitrite, hydrochloride, bromate, iodate, sulfate, sulfite, and bisulfate, and the organic salt may be, for example, acetate, adipine, aspartate, benzoate, benzenesulfonate, camphorsulfonate, citrate, cyclohexylaminesulfonate, ethylenedisulfonate, formate, fumarate, glucoheptonate, gluconate, gluc The metal complex may be at least one of the following: rosate, hexafluorophosphate, 2-hydroxyethanesulfonate, lactate, malate, maleate, malonate, methanesulfonate, methylsulfate, naphthoate, 2-naphthalenesulfonate, nicotinate, nitrate, oxalate, hexadecanate, pyroglutamate, saccharate, stearate, salicylate, tannate, tartrate, tosylate, and trifluoroacetate. The metal complex may be, for example, an ammonium salt or a solution of metallic ammonia.

[0017] Regarding the reducing agent of the present invention, in the manufacturing method of the present invention, the type of reducing agent is not particularly limited, and any reducing agent that has sufficient reducing ability to reduce the metal source in the oxidizing agent to a metal is acceptable. For example, in one embodiment of the present invention, the reducing agent is a hydrazine-based (hydrazine, hydrazine monohydrate, phenylhydrazine, hydrazine sulfate, etc.), an amine-based (dimethylaminoethanol, triethylamine, octylamine, dimethylaminoborane, etc.), an organic acid-based (citric acid, ascorbic acid, tartaric acid, malic acid, malonic acid, or salts thereof, formic acid, formaldehyde, etc.), an alcohol-based (methanol, ethanol, isopropyl alcohol, ethylene glycol, diglycol, triglycol, tetraglycol, benzotriazole, etc.), an aldehyde-based (formaldehyde, acetaldehyde, propionaldehyde) The reducing agent is at least one selected from the following: d), hydrogen compound-based (sodium borohydride, lithium borohydride, triethyllithium borohydride, lithium aluminum hydride, diisobutylaluminum hydride, tributyltin hydride, tri-sec-butyllithium borohydride, tri-sec-butylpotassium borohydride, zinc borohydride, sodium acetoxyborohydride), transition metal salt-based (ferrous sulfate, tin sulfate), pyrrolidone-based (polyvinylpyrrolidone, 1-vinylpyrrolidone, N-vinylpyrrolidone, methylpyrrolidone), and hydroxyamine-based (hydroxylamine sulfate, hydroxylamine nitrate) reducing agents.

[0018] Regarding the amounts of the first dispersant, the second dispersant, the oxidizing agent, and the reducing agent used in the manufacturing method of the present invention, in one embodiment of the present invention, the molar amount of the reducing agent may be 0.1 to 9 times, preferably 0.5 to 7 times, and more preferably 1 to 5 times (for example, 1, 2, 3, 4, or 5 times, preferably to complete the oxidation-reduction reaction) compared to the molar amount of the metal (i.e., the metal source) in the oxidizing agent. If the amount of the reducing agent used is too low, unreduced metal may remain, and if the amount of the reducing agent used is too high, the reaction may be too fast, leading to an increase in aggregated particles and an increase in the final particle size deviation. In another embodiment of the present invention, the weight of the first dispersant may be 0.1 to 40 wt% (e.g., 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, or 40 wt%) relative to the weight of the metal (i.e., metal source) in the oxidizing agent, the weight of the second dispersant may be 1 to 60 wt% (e.g., 1 wt%, 5 wt%, 10 wt%, 20 wt%, 40 wt%, or 60 wt%), and the weight of the nanoparticles may be 0.0001 to 1.0 wt% (e.g., 0.0001 wt%, 0.001 wt%, 0.01 wt%, 0.1 wt%, or 1 wt%), but preferably 0.005 to 0.01 wt%.

[0019] Furthermore, the reaction conditions for the manufacturing method of the present invention may be at room temperature or under appropriately heated conditions. For example, in one embodiment of the present invention, the reaction may be carried out at a temperature of 1 to 90°C, preferably 20 to 80°C, more preferably 25 to 50°C (e.g., 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C). In order to achieve a uniform reaction, the manufacturing method of the present invention may be carried out with stirring, for example, the stirring speed may be 5 rpm to 1000 rpm.

[0020] In particular, the manufacturing method of the present invention may include a step of adding a flocculant after or before the oxidation-reduction reaction, but by selecting a different dispersant, it may be possible to eliminate the need to add a flocculant, and the flocculant can change the electrostatic potential on its surface to which particles and other particles are bound, and then separate them to obtain nanometal particles that do not contain mother liquor. In one embodiment of the present invention, the flocculant may be selected from lipid compounds, carboxylic acid compounds or inorganic salts. More specifically, in one embodiment of the present invention, the lipid compound comprises lipid precursors and derivatives thereof, such as saturated fatty acids and their salts or unsaturated fatty acids and their salts, preferably the saturated fatty acid being at least one selected from caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid, the unsaturated fatty acid being at least one selected from oleic acid, linoleic acid, sorbic acid, linolenic acid, and arachidonic acid, the carboxylic acid compound being at least one of compounds having a carbon-carbon double bond, dicarboxyl compounds, and dihydroxy compounds, and the inorganic salt being at least one selected from sulfates, nitrates, and ammonium salts, but not limited thereto. In another embodiment of the present invention, the amount of flocculant added may be 0.001% to 20% of the weight of the metal particles (for example, 0.001%, 0.01%, 0.1%, 1%, 10%, 15%, or 20%).

[0021] In another embodiment, the present invention also provides metal particles produced by the method described above.

[0022] As described above, due to the action of the first dispersant and the second dispersant, the metal particles of the present invention obtained through the redox reaction have voids. In addition to closed voids formed inside the metal fine particles in the one-step reaction process, these voids include voids formed between the metal fine particles in the two-step reaction process, and the voids between the metal fine particles may open to the surface of the metal particles. Therefore, the metal particles according to the present invention have advantages such as high shrinkage ratio, large specific surface area, and high sphericity, and can be applied to technical fields such as printed circuit boards and solar cells. In one embodiment of the present invention, the porosity of the metal particles may be 2.97% or more.

[0023] It should be understood that any endpoint and any value of the ranges disclosed in the present specification are not limited to the exact ranges or values, and these ranges or values should be construed to include values close to these ranges or values. In the case of numerical ranges, one or more new numerical ranges can be obtained by combining the endpoint values of each range, the endpoint values of each range and individual point values, and individual point values with each other, and these numerical ranges should be regarded as specifically disclosed in the present specification.

[0024] Before describing the present invention in detail, it should be understood that the terms used herein are only for describing specific embodiments and are not intended to limit the scope of the present invention, and the scope of the present invention is intended to be limited only by the appended claims. In order to more fully understand the present invention described herein, the following terms are used, and their definitions are as follows. Unless otherwise specifically defined, technical and scientific terms used herein have the same meanings as understood by those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are provided for further understanding of the present invention, and constitute a part of the present specification. They are used to explain the present invention together with the following specific embodiments, but do not limit the present invention. [Figure 1]Shows silver metal particles produced according to Example 1 of the present invention. [Figure 2] Shows the result of observing a single silver metal particle produced according to Example 2 of the present invention under a microscope, and shows that the surface of this particle has a porous structure. [Figure 3] Shows the result of observing a single silver metal particle produced according to Example 2 of the present invention under a microscope, and shows that one fine particle is not completely polymerized on the surface of the silver particle. [Figure 4] Shows the result of observing a single silver metal particle produced according to Example 3 of the present invention under a microscope. [Figure 5] Shows a cross-sectional view obtained by cutting a single particle among silver metal particles produced according to Example 1 of the present invention at a magnification of 80K. [Figure 6] Shows a cross-sectional view obtained by cutting a single particle among silver metal particles produced according to Example 2 of the present invention at a magnification of 50K. [Figure 7] Shows a cross-sectional view obtained by cutting another single particle among silver metal particles produced according to Example 2 of the present invention at a magnification of 50K. [Figure 8] Shows a cross-sectional view obtained by cutting a single particle among silver metal particles produced according to Example 3 of the present invention at a magnification of 50K. [Figure 9] Shows a cross-sectional view obtained by cutting a single particle among silver metal particles produced according to Example 4 of the present invention at a magnification of 50K. [Figure 10] Shows a cross-sectional view obtained by cutting a single particle among silver metal particles produced according to Comparative Example 1 of the present invention at a magnification of 50K. [Figure 11] It is a partial enlarged view of FIG. 9. MODE FOR CARRYING OUT THE INVENTION

[0026] Hereinafter, specific embodiments of the present invention will be described in detail. It should be understood that the specific embodiments described herein are for purposes of description and interpretation of the present invention only, and are not intended to limit the present invention.

[0027] In the following examples, FIB-SEM technology is employed as a method for cutting metal particles. A gallium particle focused ion beam is used to cut the metal particles, exposing the cross-sections of individual metal particles. Then, the cross-sections of the particles are observed using a scanning electron microscope (SEM).

[0028] Examples Example 1 A first dispersant was prepared by mixing 10 mL of sorbitol and 35 μg of 40-90 nm cellulose. Carboxymethylcellulose was dissolved in 35 mL of water to prepare a 6.5% solution by mass, which was used as the second dispersant. The first and second dispersants prepared above were mixed and stirred uniformly to obtain a dispersant system, and the solution was maintained at a constant temperature of 35°C.

[0029] Furthermore, 17 g of silver nitrate was added to a beaker containing a certain amount of water and stirred uniformly. The resulting silver nitrate solution was then added to the dispersant system. Next, while stirring, a 20% solution containing 20 g of hydroxylamine sulfate was added. After the reaction, oleic acid was added to obtain silver metal particles with a porous structure. The results observed under a microscope are shown in Figure 1.

[0030] Example 2 A first dispersant was prepared by mixing 15 mL of maleic acid with 20 μg of 20-50 nm nano-spherical silver oxide. A second dispersant was prepared by dissolving 3.5 g of gum arabic in 50 mL of water. The first and second dispersants were mixed and stirred uniformly to obtain a dispersant system, and the solution was maintained at a constant temperature of 35°C.

[0031] A 25% solution containing 20 g of ascorbic acid was prepared, and the ascorbic acid solution was added to the dispersant system prepared as described above. Then, 17 g of silver nitrate was added to 50 mL of aqueous solution and mixed uniformly. Next, the silver nitrate solution was added to the above solution while stirring and reacted. After the reaction, lauric acid was added to obtain silver metal particles with a porous structure. Microscopic results are shown in Figures 2 and 3. The particle size of the silver metal particles shown in Figure 2 was 2.2 μm, and the particle size of the silver metal particles shown in Figure 3 was 1.5 μm, but this shows cases where a single fine particle was not completely polymerized on the surface of the silver particle.

[0032] Example 3 3 g of Tween and 15 μg of 10-20 nm nano-silver were mixed in water to obtain the first dispersant. PVP was dissolved in 35 mL of water to prepare a 6.5% mass solution, which was used as the second dispersant. The first and second dispersants prepared above were mixed and stirred uniformly to obtain a dispersant system, and the solution was maintained at a constant temperature of 25°C.

[0033] Furthermore, 15g of VC was added to a beaker containing a certain amount of water and stirred uniformly. The resulting VC solution was then added to the dispersant system. Next, while stirring, a 20% solution containing 10g of silver nitrate was quickly added. After the reaction, oleylamine was added to obtain silver metal particles with a porous structure. The results under a microscope are shown in Figure 4.

[0034] Example 4 5 g of sodium alkylbenzene sulfonate was dissolved in water and mixed with 10 μg of 10-90 nm nano silicon dioxide to obtain the first dispersant. 3.5 g of polyvinylpyrrolidone was dissolved in 35 mL of water to prepare a solution, which served as the second dispersant. The first and second dispersants prepared above were mixed and uniformly stirred to obtain a dispersant system, and the solution was maintained at a constant temperature of 30°C.

[0035] Next, while stirring the dispersant system, a 28% solution containing 17 g of 30% silver nitrate solution and 5 g of aqueous hydrazine was added. After the reaction, sodium stearate was added to obtain silver metal particles having a porous structure.

[0036] Comparative Example 1 15 μg of 10-20 nm nano-silver was mixed with PVP to prepare a 9% mass solution, which was used as a dispersant, and the solution was maintained at a constant temperature of 25°C.

[0037] After adding 25g of VC to a beaker containing a certain amount of water and stirring uniformly, the resulting VC solution was added to the dispersant system. Then, while stirring, a 25% solution containing 15g of silver nitrate was quickly added. After the reaction, linoleic acid was added to obtain silver metal particles.

[0038] The metal particles in Examples 1-4 and Comparative Example 1 described above were cut. As described above, FIB-SEM technology was used for cutting the metal particles, and the metal particles were cut using a gallium particle focused ion beam, so that the cross-section of each metal particle was exposed, and then the cross-section of the particles was observed using a scanning electron microscope (SEM). A schematic cross-sectional view of the metal particles obtained in Example 1 is shown in Figure 5, the schematic cross-sectional views of the metal particles obtained in Example 2 are shown in Figures 6 and 7, the schematic cross-sectional views of the metal particles obtained in Examples 3 and 4 are shown in Figures 8 and 9, and the schematic cross-sectional view of the metal particles obtained in Comparative Example 1 is shown in Figure 10.

[0039] In SEM observation, orthographic projection was used to identify various contrasts in the image, and the particle size, cross-sectional area, and void area of ​​the silver metal particles shown in Figures 5-10 were calculated under various contrasts. The results are shown in Table 1 below. Of these, the measurement results were calculated using the average of three measurements, and the porosity = void area / cross-sectional area of ​​the silver metal particle.

[0040] [Table 1]

[0041] As can be seen from the results in Figures 5-10 and Table 1, the porosity of the silver metal particles obtained by the method of Comparative Example 1 was low, only reaching 0.25%. In contrast, the silver metal particles produced by the exemplary methods of the present invention (Examples 1-4) have a large specific surface area, a high shrinkage ratio, high sphericity, and a porosity of at least 2.97%, and can even reach 11.16%.

[0042] Furthermore, Figure 11 is a partially enlarged view of Figure 9, clearly showing the voids in the metal particles of the present invention. These voids consist of two types: voids within newly generated one-step metal nanoparticles and large voids between metal nanoparticles formed during the metal nanoparticle polymerization process in the two-step reaction.

[0043] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, several simple modifications can be made to the technical solution means of the present invention, and all of these simple modifications fall within the scope of protection of the present invention.

[0044] Furthermore, each specific technical feature described in the above-mentioned specific embodiments can be combined in any suitable manner, as long as they do not contradict each other. To avoid unnecessary redundancy, various possible combinations are not described separately in this invention.

[0045] Furthermore, any combination of the various different embodiments of the present invention is possible and should be considered as being disclosed herein, as long as it does not contradict the spirit of the invention.

Claims

1. The step includes a step of obtaining metal particles by causing a redox reaction between a metal source-containing oxidizing agent and a reducing agent in the presence of a first dispersant and a second dispersant. The first dispersant comprises a first low molecular weight organic solvent and at least one nanoparticle, wherein the nanoparticle is at least one selected from organic nanoclusters, nonmetallic oxides, metal oxides, or metal inorganic salts, and The second dispersant contains a high molecular weight second organic solvent, The first organic solvent is an organic solvent with a molecular weight of 1200 Da or less, and the second organic solvent is an organic solvent with a molecular weight of more than 1200 Da. The first and second organic solvents are each independently at least one selected from organic acids, gum arabic, ester-based, ether-based, ether ester-based, ketone-based, amine-based, alcohol-based, pyridine-based, and pyrrolidone-based organic solvents. A method for manufacturing metal particles.

2. The method according to claim 1, wherein the first organic solvent is at least one selected from fatty acids and their salts, alkyl sulfates and their salts, alkylbenzenesulfonic acids and their salts, linear alkylbenzenesulfonic acids and their salts, maleic acid and its salts, 1-vinylpyrrolidone, N-vinylpyrrolidone, methylpyrrolidone, polyoxyethylene lauryl ether sulfate triethanolamine, octylamine, ethanol, polyethylene glycol, alkyl sulfate triethanolamine, glycerol, alkyl ether sulfate salts, sorbitol, sorbitan, polysorbate, sorbitan fatty acid esters, lecithin, polysorbate dialkyldimethylammonium chloride, alkylpyridinium chloride, polyoxyethylene alkyl ether (AE), polyoxyethylene alkylphenyl ether (APE), alkylcarboxybetaine, and sulfobetaine.

3. The step includes a step of obtaining metal particles by causing a redox reaction between a metal source-containing oxidizing agent and a reducing agent in the presence of a first dispersant and a second dispersant. The first dispersant comprises a first low molecular weight organic solvent and at least one elemental metal nanoparticle. The first organic solvent is at least one selected from fatty acids and their salts, alkyl sulfates and their salts, alkylbenzenesulfonic acids and their salts, linear alkylbenzenesulfonic acids and their salts, maleic acid and its salts, alkyl ether sulfate salts, polysorbates, sorbitan fatty acid esters, lecithin, and polysorbate dialkyldimethylammonium chloride. and The second dispersant contains a high molecular weight second organic solvent, The first organic solvent is an organic solvent with a molecular weight of 1200 Da or less, the second organic solvent is an organic solvent with a molecular weight of more than 1200 Da, and the second organic solvent is at least one selected from organic acids, gum arabic, ester-based, ether-based, ether ester-based, ketone-based, amine-based, alcohol-based, pyridine-based, and pyrrolidone-based organic solvents. A method for manufacturing metal particles.

4. The method according to claim 1 or claim 3, wherein the second organic solvent is at least one selected from gum arabic, formaldehyde condensate of naphthalene sulfonate, polyacrylate, copolymer salt of vinyl compound and carboxylic acid monomer, carboxymethylcellulose, polyvinyl alcohol, polyethylene glycol, partially alkyl polyacrylate and / or polyalkylene polyamine, polyethyleneimine and / or aminoalkyl methacrylate copolymer, polyvinylpyrrolidone, polystyrene sulfonic acid, polyacrylic acid, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenyl ether.

5. The method according to claim 1, wherein the size of the nanoparticles is 0.1 to 90 nm.

6. The method according to claim 5, wherein the organic nanocluster is at least one selected from cellulose and organic carbohydrates, the nonmetallic oxide is at least one selected from oxides of silicon, carbon and nitrogen, the metal oxide is at least one selected from oxides of gold, silver, platinum, palladium, cobalt, copper, nickel and zinc, and the inorganic metal salt is selected from metal sulfates or nitrates.

7. The method according to claim 1 or claim 3, wherein the metal source-containing oxidizing agent is at least one selected from inorganic metal salts, organometallic salts, and metal complexes.

8. The method according to claim 7, wherein the metal of the metal source-containing oxidizing agent is at least one of gold, silver, platinum, palladium, cobalt, copper, nickel, and zinc.

9. The method according to claim 1 or claim 3, wherein the reducing agent is at least one selected from hydrazine-based, amine-based, organic acid and its salt-based, alcohol-based, aldehyde-based, hydrogen compound-based, transition metal salt-based, pyrrolidone-based, and hydroxyamine-based reducing agents.

10. The method according to claim 1 or claim 3, wherein the weight of the first dispersant is 0.1 to 40 wt%, the weight of the second dispersant is 1 to 60 wt%, and the weight of the nanoparticles is 0.0001 to 1.0 wt%, relative to the weight of the metal in the oxidizing agent.

11. The method according to claim 1 or 3, further comprising the step of adding a flocculant after or before the aforementioned oxidation-reduction reaction.

12. The method according to claim 11, wherein the flocculant is selected from lipid compounds, carboxylic acid compounds, or inorganic salts.

13. The method according to claim 12, wherein the lipid compound is a saturated fatty acid and its salt, or an unsaturated fatty acid and its salt.

14. The method according to claim 13, wherein the lipid compound is, the saturated fatty acid is at least one selected from caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid, the unsaturated fatty acid is at least one selected from oleic acid, linoleic acid, sorbic acid, linolenic acid, and arachidonic acid, the carboxylic acid compound is at least one selected from a compound having a carbon-carbon double bond, a dicarboxyl compound, and a dihydroxy compound, and the inorganic salt is at least one selected from a sulfate, a nitrate, and an ammonium salt.

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