Method for producing micrometer copper particles, micrometer copper particles

Abstract

This application relates to a method for preparing micron-sized copper particles and the micron-sized copper particles themselves. The method for preparing micron-sized copper particles includes: mixing a copper source, a first particle size modifier, a second particle size modifier, a surface smoother, a surfactant, and a first solvent to prepare system A; mixing a reducing agent with a second solvent to prepare system B; mixing system A and system B and performing a reduction reaction, followed by solid-liquid separation to prepare micron-sized copper particles. The molar ratio of the second particle size modifier to the first particle size modifier is 1:(1~10). This preparation method, by adjusting the specific molar ratio of the first and second particle size modifiers, achieves controllable adjustment of the particle size of the obtained micron-sized copper particles, enabling the acquisition of micron-sized copper particles with regular morphology and high purity.

Description

Technical Field

[0001] This application relates to the field of conductive materials technology, and in particular to a method for preparing micron-sized copper particles and the micron-sized copper particles themselves. Background Technology

[0002] Micron-sized copper particles, due to their advantages such as low sintering temperature, low softening temperature, high specific surface area, and excellent electrical and thermal conductivity, have become one of the core materials in key fields such as integrated circuits, solar photovoltaics, new energy, lubrication, and chemical catalysis. With the rapid and high-quality development of global industry and the electronics, information technology, and new energy industries, the demand for high-performance micron-sized copper particle materials continues to rise.

[0003] The liquid-phase reduction method for producing micron-sized copper particles involves reacting copper salts with a suitable reducing agent in a liquid phase, followed by washing, drying, and sieving to obtain micron-sized copper particles. The liquid-phase reduction method has attracted much attention due to its advantages, including low reaction temperature, simple process, high safety, easy control of composition, and uniform particle size and good dispersibility of the produced copper particles. It is currently the mainstream method for preparing copper particles and has promising prospects for industrialization.

[0004] High-performance micron-sized copper particles typically require a relatively regular spherical morphology and a high copper content, while also meeting certain particle size requirements. However, when preparing micron-sized copper particles using the liquid-phase reduction method, the morphology, copper content, and particle size of the micron-sized copper particles are affected by the cumulative effects of various reagents in the system. For example, when adjusting the particle size of the micron-sized copper particles, the morphology of the resulting micron-sized copper particles also changes continuously, ultimately making it difficult to obtain micron-sized copper particles that simultaneously possess a regular spherical morphology, high copper content, and controllable particle size. Summary of the Invention

[0005] Therefore, it is necessary to provide a method for preparing micron-sized copper particles with high copper content, regular morphology, and relatively controllable particle size, as well as micron-sized copper particles.

[0006] In a first aspect, this application provides a method for preparing micron-sized copper particles.

[0007] A method for preparing micron-sized copper particles includes the following steps:

[0008] System A is prepared by mixing a copper source, a first particle size modifier, a second particle size modifier, a surface smoother, a surfactant, and a first solvent.

[0009] The reducing agent is mixed with the second solvent to prepare system B;

[0010] System A and system B are mixed and subjected to a reduction reaction, followed by solid-liquid separation to obtain micron-sized copper particles.

[0011] Wherein, the molar ratio of the first particle size regulator and the second particle size regulator is (1~10):1;

[0012] The first solvent includes water and alcohol solvents, and the second solvent includes water;

[0013] The first particle size modifier includes at least one of ammonia, ethylamine, ethylenediamine, triethylamine, pyridine, piperidine, benzyltrimethylammonium hydroxide, and triethylenediamine;

[0014] The second particle size regulator includes at least one of ammonium sulfate, ammonium chloride, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, succinic acid, tartaric acid, benzoic acid, phthalic acid, pyromellitic acid, and pyromellitic acid.

[0015] In some embodiments, the first particle size modifier comprises piperidine, and the second particle size modifier comprises sodium dihydrogen phosphate; and / or

[0016] The first particle size modifier comprises ethylamine, and the second particle size modifier comprises ammonium sulfate; and / or

[0017] The first particle size modifier includes triethylenediamine, and the second particle size modifier includes ammonium dihydrogen phosphate.

[0018] In some embodiments, the reducing agent includes at least one selected from sodium borohydride, potassium borohydride, sodium hypophosphite, and hydrazine hydrate; and / or

[0019] The surfactant comprises at least one of sodium stearate, sodium dodecylbenzene sulfonate, tetrabutylammonium bromide, n-octyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, sodium carboxymethyl cellulose, and sodium alginate; and / or

[0020] The surface smoothing agent includes at least one of ethylene glycol ethyl ether, ethylene glycol butyl ether, ethyl ether, diethyl ether, diethylene glycol methyl ethyl ether, vinyl isobutyl ether, vinyl ethyl ether, and butyl ethyl ether.

[0021] In some embodiments, the concentration of the copper source in system A is 0.1 mol / L to 2.5 mol / L.

[0022] In some embodiments, the concentration of the surfactant in system A is 0.01 mol / L to 1 mol / L.

[0023] In some embodiments, the concentration of the surface smoothing agent in system A is 0.01 mol / L to 1 mol / L.

[0024] In some embodiments, the molar ratio of the copper source to the reducing agent is 1:(0.5~6).

[0025] In some embodiments, when preparing system A, the molar ratio of the copper source to the sum of the first particle size modifier and the second particle size modifier is 1:(0.5~1.2).

[0026] In some embodiments, the reduction reaction conditions include reacting at 40°C to 100°C for 0.5 h to 20 h.

[0027] In a second aspect, this application provides a micron-sized copper particle.

[0028] A micron-sized copper particle is prepared using the aforementioned method for preparing micron-sized copper particles; the micron-sized copper particle is spherical or near-spherical.

[0029] The method for preparing micron-sized copper particles in this application uses a combination of a specific first particle size regulator and a second particle size regulator as particle size regulators for copper particles. By controlling the molar ratio of the two, the particle size of the obtained micron-sized copper particles can be controlled. On this basis, the surface morphology and shape of the micron-sized copper particles are further optimized by using a surface smoothing agent adapted to the particle size regulator, and finally high-purity micron-sized copper particles with an average particle size of about 1 μm to 10 μm and a regular spherical or near-spherical morphology are obtained. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a morphology diagram of the micron-sized copper particles obtained in Example 1 of this application.

[0032] Figure 2 This is a morphology diagram of the micron-sized copper particles obtained in Example 2 of this application.

[0033] Figure 3 This is a morphology diagram of the micron-sized copper particles obtained in Example 3 of this application.

[0034] Figure 4 This is a morphology diagram of the micron-sized copper particles obtained in Example 4 of this application.

[0035] Figure 5 This is a morphology diagram of the micron-sized copper particles obtained in Example 5 of this application.

[0036] Figure 6 This is a morphology diagram of the micron-sized copper particles obtained in Example 6 of this application.

[0037] Figure 7 This is a morphology diagram of the micron-sized copper particles obtained in Example 7 of this application.

[0038] Figure 8 This is a morphology diagram of the micron-sized copper particles obtained in Example 8 of this application.

[0039] Figure 9 This is a topographic image of the surface profile of the micron-sized copper particles obtained in Example 3 of this application.

[0040] Figure 10 This is a scatter plot showing the corresponding particle size of micron-sized copper particles and the molar ratio of the first and second particle size modifiers in the reaction system.

[0041] Figure 11 This is a morphology diagram of the micron-sized copper particles obtained in Comparative Example 1 of this application.

[0042] Figure 12 This is a morphology diagram of the micron-sized copper particles obtained in Comparative Example 2 of this application.

[0043] Figure 13 This is a morphology diagram of the micron-sized copper particles obtained in Comparative Example 3 of this application.

[0044] Figure 14 This is a morphology diagram of the micron-sized copper particles obtained in Comparative Example 4 of this application.

[0045] Figure 15 This is a morphology diagram of the micron-sized copper particles obtained in Comparative Example 5 of this application.

[0046] Figure 16 This is a morphology diagram of the micron-sized copper particles obtained in Comparative Example 6 of this application.

[0047] Figure 17 This is a morphology diagram of the micron-sized copper particles obtained in Comparative Example 7 of this application. Detailed Implementation

[0048] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0049] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. In this application, "at least one" means one or more, such as one, two, or more than two. "Multiple" or "several" means at least two, such as two, three, etc.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0051] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0052] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0053] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0054] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0055] Chemical methods for preparing nano- and micro-sized copper particles mainly include the sol-gel method, electrolysis, microemulsion method, gas-phase reduction method, and liquid-phase reduction method. Among these, the electrolysis method is energy-intensive, produces significant pollution from the electrolytic waste liquid, and generally yields dendritic copper particles, making it difficult to obtain spherical or near-spherical particles. The sol-gel and microemulsion methods have low copper ion concentrations in the reaction system and require large amounts of surfactants, resulting in large volumes of waste liquid and low economic efficiency. The gas-phase reduction method mainly uses reducing gases (such as hydrogen) to reduce copper-containing precursor powders (such as basic copper carbonate, cuprous oxide, etc.) to obtain elemental copper particles. However, the morphology and particle size of the product are mainly determined by the quality of the precursor powder; therefore, this method involves numerous steps, complex processes, and many influencing factors, making it unsuitable for large-scale production.

[0056] The liquid-phase reduction method for producing micron-sized copper particles involves reacting copper salts with a suitable reducing agent in a liquid phase, followed by washing, drying, and sieving to obtain micron-sized copper particles. The liquid-phase reduction method has attracted much attention due to its advantages, including low reaction temperature, simple process, high safety, easy control of composition, and uniform particle size and good dispersibility of the produced copper particles. It is currently the mainstream method for preparing copper particles and has promising prospects for industrialization.

[0057] High-performance micron-sized copper particles typically require a relatively regular spherical morphology and a high copper content, while also meeting certain particle size requirements. However, when preparing micron-sized copper particles using the liquid-phase reduction method, the morphology, copper content, and particle size of the micron-sized copper particles are affected by the cumulative effects of various reagents in the system. For example, when adjusting the particle size of the micron-sized copper particles, the morphology of the resulting micron-sized copper particles also changes continuously, ultimately making it difficult to obtain micron-sized copper particles that simultaneously possess a regular spherical morphology, high copper content, and controllable particle size.

[0058] Based on this, the first aspect of this application provides a method for preparing micron-sized copper particles with controllable particle size, high copper content, and regular morphology.

[0059] For example, a method for preparing micron-sized copper particles includes the following steps:

[0060] System A is prepared by mixing a copper source, a first particle size modifier, a second particle size modifier, a surface smoother, a surfactant, and a first solvent.

[0061] The reducing agent is mixed with the second solvent to prepare system B;

[0062] System A and system B were mixed and subjected to a reduction reaction, followed by solid-liquid separation to obtain micron-sized copper particles.

[0063] The molar ratio of the second particle size modifier to the first particle size modifier is 1:(1~10);

[0064] The first solvent includes water and alcohol solvents, and the second solvent includes water;

[0065] The first particle size modifier includes at least one of ammonia, ethylamine, ethylenediamine, triethylamine, pyridine, piperidine, benzyltrimethylammonium hydroxide, and triethylenediamine.

[0066] The second particle size modifier includes at least one of ammonium sulfate, ammonium chloride, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, succinic acid, tartaric acid, benzoic acid, phthalic acid, pyromellitic acid, and pyromellitic acid.

[0067] The above-mentioned method for preparing micron-sized copper particles uses a combination of a specific first particle size regulator and a second particle size regulator as particle size regulators for copper particles. By controlling the molar ratio of the two, the particle size of the obtained micron-sized copper particles can be controlled. On this basis, the surface morphology and shape of the micron-sized copper particles are further optimized by using a surface smoothing agent that is compatible with the particle size regulator, and finally high-purity micron-sized copper particles with an average particle size of 1μm to 10μm and a spherical or near-spherical morphology are obtained.

[0068] In some embodiments, the water content in the first solvent is 70% to 100% by mass. The method for preparing micro / nano copper particles of this application can be used in aqueous systems or even pure water systems. The total organic carbon (TOC) content in the mother liquor after the reaction is low, and the mother liquor can be recycled, which not only helps to achieve green production, but also reduces the difficulty of wastewater treatment.

[0069] In some embodiments, the first particle size modifier includes piperidine, and the second particle size modifier includes sodium dihydrogen phosphate. Studies have shown that maintaining the first and second particle size modifiers in this combination yields a more stable particle size control effect.

[0070] In some embodiments, the first particle size modifier includes ethylamine, and the second particle size modifier includes ammonium sulfate. Studies have shown that maintaining the first and second particle size modifiers in this combination yields a more stable particle size control effect.

[0071] In some embodiments, the first particle size modifier includes triethylenediamine, and the second particle size modifier includes ammonium dihydrogen phosphate. Studies have shown that maintaining the first and second particle size modifiers in this combination yields a more stable particle size control effect.

[0072] In some embodiments, the reducing agent includes at least one of sodium borohydride, potassium borohydride, sodium hypophosphite, and hydrazine hydrate.

[0073] In some embodiments, the surfactant includes at least one of sodium stearate, sodium dodecylbenzene sulfonate, tetrabutylammonium bromide, n-octyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, sodium carboxymethyl cellulose, and sodium alginate.

[0074] In some embodiments, the surface smoother includes at least one of ethylene glycol ethyl ether, ethylene glycol butyl ether, ethyl ether, diethyl ether, diethylene glycol methyl ethyl ether, vinyl isobutyl ether, vinyl ethyl ether, and butyl ethyl ether.

[0075] In some embodiments, the concentration of the copper source in system A is 0.1 mol / L to 2.5 mol / L. Optionally, the concentration of the copper source in system A can be, but is not limited to, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, or other values ​​within the range of 0.1 mol / L to 2.5 mol / L.

[0076] In some embodiments, the molar ratio of copper source to reducing agent is 1:(0.5~6). Optionally, the molar ratio of copper source to reducing agent can be, but is not limited to, other values ​​within the range of 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6 or 1:(0.5~6).

[0077] In some embodiments, the concentration of the reducing agent in system B is 0.1 mol / L to 6 mol / L. Optionally, the concentration of the reducing agent in system B can be, but is not limited to, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, or other values ​​within the range of 0.1 mol / L to 6 mol / L.

[0078] In some embodiments, the concentration of the surfactant in system A is 0.01 mol / L to 1 mol / L. Optionally, the concentration of the surfactant in system A can be, but is not limited to, 0.01 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, or other values ​​within the range of 0.01 mol / L to 1 mol / L.

[0079] In some embodiments, the concentration of the surface smoother in system A is 0.01 mol / L to 1 mol / L. Optionally, the concentration of the surface smoother in system A can be, but is not limited to, 0.01 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, or other values ​​within the range of 0.01 mol / L to 1 mol / L.

[0080] In some embodiments, the concentration of the first particle size modifier in system A is 0.1 mol / L to 2 mol / L. Optionally, the concentration of the first particle size modifier in system A can be, but is not limited to, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2 mol / L, or other values ​​within the range of 0.01 mol / L to 1 mol / L.

[0081] In some embodiments, when preparing system A, the molar ratio of the copper source to the sum of the first and second particle size modifiers is 1:(0.5~1.2). Optionally, the molar ratio of the copper source to the sum of the first and second particle size modifiers can be, but is not limited to, other values ​​within the range of 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, or 1:(0.5~1.2).

[0082] In some embodiments, the process of mixing system A and system B to carry out a reduction reaction is as follows:

[0083] Mix system A with system B and carry out the reduction reaction at 40℃~100℃ for 0.5 h~20 h.

[0084] Optionally, the reduction reaction time can be, but is not limited to, 0.5h, 5h, 10h, 15h, 20h, or other values ​​within the range of 0.5h to 20h.

[0085] Optionally, the temperature of the reduction reaction can be, but is not limited to, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or other values ​​within the range of 40°C to 100°C.

[0086] In some of these embodiments, the solid-liquid separation methods include one or more of sedimentation, filtration, centrifugation, rotary evaporation, and vacuum distillation.

[0087] In some embodiments, the solid product after solid-liquid separation is washed and dried. The washing solvent includes at least one of water, methanol, and ethanol; the drying temperature is 40°C to 90°C, and the drying time is 1 hour to 12 hours.

[0088] In a second aspect, this application provides micron-sized copper particles prepared using the above-described method. The micron-sized copper particles are spherical or near-spherical.

[0089] In some of these embodiments, the copper content of the micron-sized copper particles is ≥99.5%.

[0090] In some of these embodiments, the average particle size of the micron-sized copper particles is 1 μm to 10 μm.

[0091] The present application will be further described in detail below with reference to specific embodiments.

[0092] Unless otherwise specified, the raw materials used in the following specific embodiments and comparative examples are all commercially available products; the instruments used are all commercially available products; and the processes used are all conventionally selected by those skilled in the art unless otherwise specified.

[0093] Example 1

[0094] This embodiment provides a micron-sized copper particle. Please refer to [link / reference]. Figure 1 , Figure 1 The image shows the morphology of the micron-sized copper particles obtained in this embodiment. The copper powder particles are spherical, well dispersed, without agglomeration, with smooth surfaces and an average particle size of approximately 1.37 μm.

[0095] The preparation method of micron-sized copper particles includes the following steps:

[0096] Weigh out 17g of copper chloride dihydrate, 8.5g of piperidine (first particle size regulator), 1.2g of sodium dihydrogen phosphate (second particle size regulator), 1g of diethylene glycol, and 4g of sodium dodecylbenzenesulfonate. Add 900mL of water and 100mL of ethanol. Stir at 40℃ for 60min under a nitrogen atmosphere to prepare system A. The molar ratio of the second particle size regulator to the first particle size regulator is 1:10.

[0097] Weigh 19g of sodium borohydride and dissolve it in 200mL of water. Stir the solution at 40℃ for 10min under a nitrogen atmosphere to prepare system B.

[0098] System B was added to the first mixture, and the reaction was continued at 45°C for 10 hours under a nitrogen atmosphere, after which the reaction was stopped.

[0099] The reduced product was centrifuged, and the solid components were washed with water and ethanol. After washing, the product was placed in a vacuum drying oven and dried at 80°C for 12 hours to prepare micron-sized copper particles.

[0100] Example 2

[0101] This embodiment provides a micron-sized copper particle with an average particle size of approximately 2.2 μm.

[0102] The preparation method of the micron-sized copper particles in this embodiment is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 1:5.

[0103] Example 3

[0104] This embodiment provides a micron-sized copper particle with an average particle size of approximately 2.5 μm.

[0105] The preparation method of the micron-sized copper particles in this embodiment is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 3:10.

[0106] Example 4

[0107] This embodiment provides a micron-sized copper particle with an average particle size of approximately 4.3 μm.

[0108] The preparation method of the micron-sized copper particles in this embodiment is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 2:5.

[0109] Example 5

[0110] This embodiment provides a micron-sized copper particle with an average particle size of approximately 6.1 μm.

[0111] The preparation method of the micron-sized copper particles in this embodiment is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 1:2.

[0112] Example 6

[0113] This embodiment provides a micron-sized copper particle with an average particle size of approximately 6.8 μm.

[0114] The preparation method of the micron-sized copper particles in this embodiment is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 3:5.

[0115] Example 7

[0116] This embodiment provides a micron-sized copper particle with an average particle size of approximately 7.9 μm.

[0117] The preparation method of the micron-sized copper particles in this embodiment is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 4:5.

[0118] Example 8

[0119] This embodiment provides a micron-sized copper particle with an average particle size of approximately 9.2 μm.

[0120] The preparation method of the micron-sized copper particles in this embodiment is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 1:1.

[0121] Comparative Example 1

[0122] This comparative example provides micron-sized copper particles with an average particle size of approximately 0.3 μm.

[0123] The preparation method of the micron-sized copper particles in this comparative example is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 0.8:10.

[0124] Comparative Example 2

[0125] This comparative example provides micron-sized copper particles with an average particle size greater than 10 μm.

[0126] The preparation method of the micron-sized copper particles in this comparative example is basically the same as that in Example 1, except that: when preparing system A, the total molar amount of the second particle size regulator and the first particle size regulator is kept constant, and the molar ratio of the second particle size regulator and the first particle size regulator is adjusted to 1.2:1.

[0127] Comparative Example 3

[0128] This comparative example provides micron-sized copper particles with an average particle size of approximately 2.37 μm.

[0129] In the preparation method of the micron-sized copper particles in this comparative example, the concentration of the surface smoothing agent is 0.008 mol / L, and the specific process is as follows:

[0130] Weigh 68g of copper chloride, 28g of potassium hydroxide, 12g of succinic acid, 0.8g of tetraethylene glycol and 22g of polyethylene glycol, add 500mL of water, and stir for 60min under a nitrogen atmosphere to obtain system A;

[0131] Weigh 60g of sodium borohydride and dissolve it in 400mL of water. Stir for 10min under a nitrogen atmosphere to obtain system B.

[0132] Mix system A and system B, and stir at 50°C for 8 hours under nitrogen atmosphere;

[0133] The reduced product was centrifuged, and the solid components were washed with water and ethanol. After washing, the product was placed in a vacuum drying oven and dried at 80°C for 12 hours to prepare micron-sized copper particles.

[0134] Comparative Example 4

[0135] This comparative example provides micron-sized copper particles with an average particle size of approximately 4.27 μm.

[0136] In the preparation method of the micron-sized copper particles in this comparative example, the concentration of the surface smoother is 1.2 mol / L, and the specific process is as follows:

[0137] Weigh 150g copper sulfate, 120g ethylenediamine, 46g formic acid, 266g sodium pyrophosphate and 7g polyvinyl alcohol, add 1000mL water, and stir for 60min under nitrogen atmosphere to obtain system A;

[0138] Weigh 300g of 50wt% hydrazine hydrate and dissolve it in 1000mL of water. Stir the solution under a nitrogen atmosphere for 10min to obtain system B.

[0139] Mix system A and system B, and stir at 50°C for 8 hours under nitrogen atmosphere;

[0140] The reduced product was centrifuged, and the solid components were washed with water and ethanol. After washing, the product was placed in a vacuum drying oven and dried at 80°C for 12 hours to prepare micron-sized copper particles.

[0141] Comparative Example 5

[0142] This comparative example provides micron-sized copper particles with an average particle size of approximately 4.27 μm.

[0143] The preparation method of the micron-sized copper particles in this comparative example is basically the same as that in Example 5, except that the surfactant concentration is 0.008 mol / L.

[0144] Comparative Example 6

[0145] This comparative example provides micron-sized copper particles with an average particle size of approximately 5.87 μm.

[0146] The preparation method of the micron-sized copper particles in this comparative example is basically the same as that in Example 5, except that the surfactant concentration is 1.2 mol / L.

[0147] Comparative Example 7

[0148] This comparative example provides micron-sized copper particles with an average particle size of approximately 1.53 μm.

[0149] The preparation method of the micron-sized copper particles in this comparative example is basically the same as that in Example 1, except that no surfactant or surface smoother is added.

[0150] Please see Figures 1-17 , Figures 1-8 The morphology images of the micron-sized copper particles obtained in Examples 1-8 are shown in sequence. Figure 9 This is a topographic image of the surface profile of the micron-sized copper particles obtained in Example 3 of this application. Figure 10 This is a scatter plot showing the corresponding particle size of micron-sized copper particles and the molar ratio of the first and second particle size modifiers in the reaction system. Figures 11-17 The morphology images of the micron-sized copper particles obtained in Examples 1 to 7 are shown in the figures above. As can be seen from the figures, Figure 13 The surface of the micron-sized copper particles has obvious irregular protrusions; Figure 14 The surface of the micron-sized copper particles has needle-like protrusions; Figure 15 The micron-sized copper particles are irregularly shaped; Figure 16 The micron-sized copper particles are polyhedral in shape and exhibit a bimodal particle size distribution. Figure 17 The micron-sized copper particles are irregularly shaped and have numerous protrusions on their surface. Examples 1-8 correspond to... Figures 1-8 The copper powder particles obtained are all spherical particles with smooth surfaces, and the particles are well dispersed without agglomeration. This indicates that the preparation method of micron copper particles in this application can obtain micron copper particles with regular morphology and relatively controllable particle size in the range of 1μm to 10μm.

[0151] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing micron-sized copper particles, characterized in that, Includes the following steps: System A is prepared by mixing a copper source, a first particle size modifier, a second particle size modifier, a surface smoother, a surfactant, and a first solvent. The reducing agent is mixed with the second solvent to prepare system B; System A and system B are mixed and subjected to a reduction reaction, followed by solid-liquid separation to obtain the micron-sized copper particles. Wherein, the molar ratio of the first particle size regulator and the second particle size regulator is (1~10):1; The first solvent includes water and alcohol solvents, and the second solvent includes water; The first particle size modifier includes at least one of ammonia, ethylamine, ethylenediamine, triethylamine, pyridine, piperidine, benzyltrimethylammonium hydroxide, and triethylenediamine; The second particle size regulator includes at least one of ammonium sulfate, ammonium chloride, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, succinic acid, tartaric acid, benzoic acid, phthalic acid, pyromellitic acid, and pyromellitic acid.

2. The method for preparing micron-sized copper particles according to claim 1, characterized in that, The first particle size modifier includes piperidine, and the second particle size modifier includes sodium dihydrogen phosphate; and / or The first particle size modifier comprises ethylamine, and the second particle size modifier comprises ammonium sulfate; and / or The first particle size modifier includes triethylenediamine, and the second particle size modifier includes ammonium dihydrogen phosphate.

3. The method for preparing micron-sized copper particles according to claim 1, characterized in that, The reducing agent includes at least one of sodium borohydride, potassium borohydride, sodium hypophosphite, and hydrazine hydrate; and / or The surfactant comprises at least one of sodium stearate, sodium dodecylbenzene sulfonate, tetrabutylammonium bromide, n-octyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, sodium carboxymethyl cellulose, and sodium alginate; and / or The surface smoothing agent includes at least one of ethylene glycol ethyl ether, ethylene glycol butyl ether, ethyl ether, diethyl ether, diethylene glycol methyl ethyl ether, vinyl isobutyl ether, vinyl ethyl ether, and butyl ethyl ether.

4. The method for preparing micron-sized copper particles according to claim 1, characterized in that, In system A, the concentration of the copper source is 0.1 mol / L to 2.5 mol / L.

5. The method for preparing micron-sized copper particles according to any one of claims 1 to 4, characterized in that, In system A, the concentration of the surfactant is 0.01 mol / L to 1 mol / L.

6. The method for preparing micron-sized copper particles according to any one of claims 1 to 4, characterized in that, In system A, the concentration of the surface smoothing agent is 0.01 mol / L to 1 mol / L.

7. The method for preparing micron-sized copper particles according to any one of claims 1 to 4, characterized in that, The molar ratio of the copper source to the reducing agent is 1:(0.5~6).

8. The method for preparing micron-sized copper particles according to any one of claims 1 to 4, characterized in that, When preparing system A, the molar ratio of the copper source to the sum of the first particle size modifier and the second particle size modifier is 1:(0.5~1.2).

9. The method for preparing micron-sized copper particles according to any one of claims 1 to 4, characterized in that, The conditions for the reduction reaction include reacting at 40℃~100℃ for 0.5 h~20 h.

10. A micron-sized copper particle, characterized in that, The micron-sized copper particles are prepared using the preparation method described in any one of claims 1 to 9; the micron-sized copper particles are spherical or near-spherical.

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