Method for preparing high-dispersion ultrafine copper powder by using water-phase copper amine complex system
The preparation of highly dispersed ultrafine copper powder using an aqueous copper-amine complex system solves the problems of complex processes, high energy consumption, and uneven product quality in existing technologies, and realizes low-cost and high-efficiency preparation and application of ultrafine copper powder.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG JICHU NEW MATERIAL TECHNOLOGY CO LTD
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies for preparing ultrafine copper powder suffer from problems such as complex processes, high energy consumption, low production capacity, poor product dispersibility, uneven particle size, and poor crystallinity, making it difficult to meet the needs of large-scale applications.
An aqueous copper-amine complex system was adopted, in which copper salt and amine reagent formed a copper-amine complex, which was then reduced to cuprous oxide precursor and subjected to a secondary high-temperature reduction to generate ultrafine copper powder. By combining various dispersants and pH control, highly dispersed ultrafine copper powder with uniform particle size distribution was prepared.
The production process has been simplified, the controllability of the reaction process has been improved, and ultrafine copper powder with uniform particle size distribution, good dispersibility and high purity has been prepared, which is suitable for industrial mass production and reduces costs and environmental pollution.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of metallic materials technology, and specifically to a method for preparing highly dispersed ultrafine copper powder in an aqueous system. Background Technology
[0002] Ultrafine copper powder is a new type of functional material with special physicochemical properties. Due to the unique structural advantages given by its ultrafine size, it exhibits excellent electrical conductivity, thermal conductivity and high specific surface area, among other core physicochemical properties. Compared with precious metals such as silver and gold, it also has the significant advantage of low cost. These properties together lay the foundation for its application in many fields and have become one of the research focuses in the field of functional materials.
[0003] With its superior properties, ultrafine copper powder possesses extremely high application value and broad application prospects, and can be widely used in various fields such as civilian, industrial, and defense sectors, demonstrating an irreplaceable role in cutting-edge technology scenarios. In the field of electronics manufacturing, high-purity ultrafine copper powder is a core material for the production and packaging of semiconductors and high-density printed circuit boards (PCBs), directly determining the stability performance of electronic devices. In the field of transparent conductive materials, polymer coatings based on copper nanowires are expected to replace traditional indium tin oxide (ITO) films, providing new solutions for scenarios such as touch screen displays and transparent conductive electrodes. In the field of catalysis, copper nanoparticles can be used as commercial catalysts in reaction processes such as water vapor conversion and pollutant detoxification, contributing to the upgrading of environmental protection and chemical industries.
[0004] In the defense and high-end industrial sectors, ultrafine copper powder also holds significant value. For example, as an additive in automotive engine lubricating oil, it can effectively reduce starting current and increase cylinder pressure. Simultaneously, it forms a dense protective film on the surfaces of cylinder liners and piston rings, ensuring long-term safe operation of vehicles even under extreme conditions of lubrication system failure, thus possessing important military application significance. Furthermore, its cost advantage makes it a potential substitute for precious metals in applications such as high-efficiency catalysts, conductive slurries, conductive adhesives, and high-grade lubricating oils, significantly reducing the production costs of related products and further expanding its application market.
[0005] Since the low resistivity of ultrafine copper powder was first discovered in 1995, its performance optimization and application expansion have become a research hotspot in the field of electronic materials, and related preparation technologies have also been continuously developed. Currently, based on the preparation principle, the preparation methods of ultrafine copper powder mainly include three categories: physical methods, chemical methods, and external field-assisted methods. Each method achieves the synthesis of ultrafine copper powder based on different technical paths, providing multiple ideas for the large-scale preparation of materials.
[0006] However, existing preparation technologies still have many shortcomings, making it difficult to balance product performance and production efficiency: they generally suffer from complex process conditions, high energy consumption, and low production capacity, which restricts large-scale applications; at the same time, the prepared products have defects such as poor monodispersity, wide particle size distribution, insufficient size uniformity, and poor crystallinity, affecting the stability and consistency of material properties. In addition, the inherent contradiction between "particle size refinement" and "process capacity improvement" in traditional processes further limits the performance iteration and industrialization of ultrafine copper powder, becoming the core technological bottleneck for the current development of this field.
[0007] In summary, while current ultrafine copper powder preparation technology has made some progress, it still falls short of meeting practical application requirements in terms of low cost, ease of operation, high production capacity, and product performance uniformity. Therefore, developing a low-cost, easy-to-operate, high-capacity method for preparing ultrafine copper powder with small particle size, high dispersibility, uniform size, and excellent crystallinity has become a key issue urgently needing to be addressed by those skilled in the art. This is of great significance for promoting the industrial application of ultrafine copper powder and expanding its application scenarios in various fields. Based on this, this application aims to provide an optimized method for preparing ultrafine copper powder to address the shortcomings of existing technologies. Summary of the Invention
[0008] To address the problems of complex processes, high energy consumption, low production capacity, poor product dispersibility, uneven particle size, and poor crystallinity in the preparation of ultrafine copper powder in existing technologies, this invention provides a method and process for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system, thereby achieving large-scale preparation of low-cost, easily scalable, and high-performance ultrafine copper powder.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] This invention provides a method and process for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system, comprising the following steps:
[0011] (1) Mix the copper source and amine reagent evenly at 20℃-30℃, add deionized water and stir to dissolve to form a copper-amine complex solution; add a dispersant solution to the copper-amine complex solution and continue to stir and mix evenly to obtain a copper source-dispersant mixed solution;
[0012] (2) The copper source-dispersant mixed solution obtained in step (1) is mixed with an aqueous solution containing an alkaline solution and a reducing agent and then reacted to obtain a cuprous oxide precursor;
[0013] (3) The cuprous oxide precursor solution obtained in step (2) is transferred to an oil bath reaction apparatus and refluxed at 80℃-120℃ for 0.5~4h. During the reaction, the mixture is continuously stirred at 300~600rpm. The cuprous oxide is reduced twice to generate ultrafine copper powder. After the reaction is completed, the product is washed, centrifuged and dried to obtain highly dispersed ultrafine copper powder.
[0014] Furthermore, the particle size of the ultrafine copper powder obtained in step (3) is 100nm≤D≤500nm.
[0015] Furthermore, in step (1), the concentration of the copper-containing solution is 0.1~3 mol / L, the concentration of the alkaline solution is 0~10 mol / L, and the molar ratio of the reducing agent in the reducing agent solution to the copper ions in the copper-containing solution is 0.1~2.0:1.
[0016] The volume ratio of the copper-containing solution, dispersant solution, alkali-containing solution, and reducing agent solution is 80~120:30~60:20~40:40~60.
[0017] Furthermore, in step (3), the reaction temperature is 80~120℃, the reaction time is 0.5~4h, and the reaction is accompanied by stirring at a speed of 300~600rpm.
[0018] Furthermore, the copper source in step (1) includes one or more of copper sulfate pentahydrate, copper nitrate, copper chloride, copper formate tetrahydrate, and copper acetate monohydrate.
[0019] Furthermore, the amine reagent in step (1) includes one or more of isopropanolamine, isobutanolamine, triethanolamine, ethanolamine and propanolamine.
[0020] Furthermore, the dispersant in step (1) includes one or more of gelatin, gum arabic, polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and hexadecyltrimethyl-p-toluenesulfonate.
[0021] Furthermore, the alkaline solution in step (2) includes one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.
[0022] Furthermore, the reducing agent in step (2) includes one or more of the following: sodium borohydride, sodium hypophosphite, glucose, formaldehyde, hydrazine hydrate, hydrogen peroxide, L-ascorbic acid, lithium borohydride, thiourea dioxide, potassium borohydride, and ferrous citrate.
[0023] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:
[0024] 1. The preparation steps of the ultrafine copper powder according to the present invention are simple. Compared with the traditional process, the present invention simplifies the production process, and the reaction process is more controllable, milder, and reduces environmental pollution.
[0025] 2. This invention addresses the characteristics of aqueous systems by using two or more mixed dispersants in the reaction system. The resulting ultrafine copper powder has a smooth surface, uniform particle size distribution, high dispersibility, good morphological consistency, and a purity of over 99% with high tap density. This solves the problems of porosity, rough surface, wide particle size distribution, poor dispersibility, and large morphological differences that easily occur when using a single dispersant.
[0026] 3. This invention abandons the traditional one-step synthesis method of directly reducing copper ions to copper and adopts a unique three-step method to prepare ultrafine copper powder. The method involves three steps: forming a copper-amine complex with copper salt and amine reagent, reducing the copper-amine complex ions to cuprous oxide precursor, and high-temperature secondary reduction of cuprous oxide to generate ultrafine copper powder. The particle size distribution of ultrafine copper powder is controlled by dynamic pH regulation, resulting in higher production capacity per unit volume, which is more conducive to industrial mass production. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the process for preparing ultrafine copper powder according to the present invention;
[0028] Figure 2 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 1 at low magnification.
[0029] Figure 3 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 1 at high magnification. It can be seen from the image that the copper particles have a smooth surface, good dispersibility, and are mostly regular spherical with a particle size distribution of about 450 nm.
[0030] Figure 4 The image shows the XRD characterization results of the ultrafine copper powder prepared in Example 1.
[0031] Figure 5 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 2 at low magnification.
[0032] Figure 6 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 2 at high magnification. It can be seen from the image that the copper particles have a smooth surface, good dispersibility, and are mostly regular spherical with a particle size distribution of about 250 nm.
[0033] Figure 7 The image shows the XRD characterization results of the ultrafine copper powder prepared in Example 2.
[0034] Figure 8The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 1. It can be seen that the copper powder obtained without adding amine reagent to the reaction system has a large difference in morphology and uneven particle size distribution.
[0035] Figure 9 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 2. It can be seen that when an alkaline solution is added to the system and the pH of the system is low, the copper powder has poor dispersibility.
[0036] Figure 10 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 3. It can be seen that when an alkaline solution is added to the system and the pH of the system is high, the surface of the copper powder is not smooth and the particle size distribution is uneven.
[0037] Figure 11 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 4. It can be seen that the copper powder obtained when polyvinylpyrrolidone (PVP) is used as a dispersant has pores and uneven particle size distribution.
[0038] Figure 12 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 5. It can be seen that the copper powder obtained when polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) are used as dispersants has pores, large particle size and uneven particle size distribution.
[0039] Figure 13 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 6. It can be seen that the copper powder obtained by using copper acetate monohydrate as the copper source and polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants has large differences in morphology and uneven particle size distribution.
[0040] Figure 14 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 7. It can be seen that when no amine reagent is added to the reaction system, the copper powder obtained by using copper formate monohydrate as the copper source and polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants has large differences in morphology and uneven particle size distribution.
[0041] Figure 15 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 8. It can be seen that without adding amine reagents to the reaction system, the copper powder obtained by using copper sulfate pentahydrate as the copper source and polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants has large differences in morphology and uneven particle size distribution. Detailed Implementation
[0042] This invention provides a method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system (process schematic diagram shown). Figure 1 The above includes the following steps:
[0043] (1) Mix the copper source and amine reagent evenly at 20℃-30℃, add deionized water and stir to dissolve to form a copper-amine complex solution; add a dispersant solution to the copper-amine complex solution and continue to stir and mix evenly to obtain a copper source-dispersant mixed solution;
[0044] (2) The copper source-dispersant mixed solution obtained in step (1) is mixed with an aqueous solution containing an alkaline solution and a reducing agent and then reacted to obtain a cuprous oxide precursor;
[0045] (3) The cuprous oxide precursor solution obtained in step (2) is transferred to an oil bath reaction apparatus and refluxed at 80℃-120℃ for 0.5~4h. During the reaction, the mixture is continuously stirred at 300~600rpm. The cuprous oxide is reduced twice to generate ultrafine copper powder. After the reaction is completed, the product is washed, centrifuged and dried to obtain highly dispersed ultrafine copper powder.
[0046] In this invention, the particle size of the ultrafine copper powder obtained in step (3) is 100nm≤D≤500nm, preferably 200nm≤D≤500nm, and more preferably 250nm≤D≤450nm.
[0047] In this invention, in step (1), the molar ratio of copper source to amine reagent is 0.1~2.0:1; the concentration of copper-containing solution is 0.1~3 mol / L; and the concentration of dispersant solution is 0.001-1 mol / L.
[0048] In this invention, in step (2), the concentration of the alkaline solution is 0 to 15 mol / L; the molar ratio of the reducing agent in the reducing agent solution to the copper ions in the copper-containing solution is 0.1 to 2.0:1.
[0049] The volume ratio of the copper-containing solution, dispersant solution, alkali-containing solution, and reducing agent solution is 60~120:20~60:20~60:30~80.
[0050] In this invention, in step (3), the reaction temperature is 80~120℃; the reaction time is 0.5~4h; the reaction is accompanied by stirring, and the stirring speed is 300~600rpm.
[0051] In this invention, after the reaction in step (3) is completed, the highly dispersible ultrafine copper powder obtained by the reaction is dried at a temperature of 50~80℃ and for a time of 12~48h. The drying method is spray drying, freeze drying, vacuum drying or drying under an inert atmosphere.
[0052] In this invention, the copper source in step (1) includes one or more of copper sulfate pentahydrate, copper nitrate, copper chloride, copper formate tetrahydrate, and copper acetate monohydrate.
[0053] In this invention, the amine reagent in step (1) includes one or more of isopropanolamine, isobutanolamine, triethanolamine, ethanolamine and propanolamine.
[0054] In this invention, the dispersant in step (1) includes one or more of gelatin, gum arabic, polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide and hexadecyltrimethyl-p-toluenesulfonate.
[0055] In this invention, the alkaline solution in step (2) includes one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.
[0056] In this invention, the reducing agent in step (2) includes one or more of sodium borohydride, sodium hypophosphite, glucose, formaldehyde, hydrazine hydrate, hydrogen peroxide, L-ascorbic acid, lithium borohydride, thiourea dioxide, potassium borohydride, and ferrous citrate.
[0057] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0058] Example 1
[0059] 10g of copper formate tetrahydrate was mixed thoroughly with 8mL of isobutanolamine and stirred at 500rpm to obtain a complex of copper formate and isobutanolamine. 90mL of water was added to the complex, and the mixture was sonicated at 120W for 5min, followed by stirring at 500rpm for 10min to obtain an aqueous solution of the copper formate and isobutanolamine complex. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium chloride (CTAC) as dispersants, 4g of PVP and 2g of CTAC were dissolved in 40mL of water to obtain a PVP / CTAC mixed solution. This PVP / CTAC mixed solution was added to the aqueous solution of the copper formate and isobutanolamine complex and stirred at 500rpm for 10min to obtain a copper source-dispersant mixture. 15g of ascorbic acid was dissolved in 50mL of water to obtain an ascorbic acid solution, which was then added to the above solution to obtain a cuprous oxide precursor solution. The cuprous oxide precursor solution was heated to 100℃ and mechanically stirred at 500 rpm, then refluxed at 100℃ for 2 hours to obtain copper nanoparticles with a size of approximately 450 nm. After repeatedly washing the copper nanoparticles 3-5 times with pure water and ethanol, the washed copper powder particles were centrifuged and placed in a vacuum oven at 65℃ for 24 hours to obtain highly dispersible ultrafine copper powder.
[0060] The results are as follows Figure 2-4 The above, Figure 2 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 1 at low magnification. Figure 3 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 1 at high magnification. It can be seen from the image that the copper particles have a smooth surface, good dispersibility, and are mostly regular spherical with a particle size distribution of about 450 nm. Figure 4 The image shows the XRD characterization results of the ultrafine copper powder prepared in Example 1.
[0061] Example 2
[0062] 10g of copper formate tetrahydrate and 8mL of isobutanolamine were mixed evenly and stirred at 500rpm to obtain a complex of copper formate and isobutanolamine. 90mL of water was added to the complex, and the mixture was sonicated at 120W for 5min, followed by stirring at 500rpm for 10min to obtain an aqueous solution of the copper formate and isobutanolamine complex. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium chloride (CTAC) as dispersants, 4g of PVP and 2g of CTAC were dissolved in 40mL of water to obtain a PVP / CTAC mixed solution. This PVP / CTAC mixed solution was added to the aqueous solution of the copper formate and isobutanolamine complex and stirred at 500rpm for 10min to obtain a copper source-dispersant mixture. 6g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was then added to the copper source-dispersant mixture and stirred at 500rpm for 5min. 15g of ascorbic acid was dissolved in 50mL of water to obtain an ascorbic acid solution. This ascorbic acid solution was then added to the above solution to obtain a cuprous oxide precursor solution. The cuprous oxide precursor solution was heated to 100℃ and mechanically stirred at 500rpm. The mixture was then refluxed at 100℃ for 2 hours to obtain copper nanoparticles with a size of approximately 250nm. After repeatedly washing the copper nanoparticles with pure water and ethanol 3-5 times, the washed copper powder particles were centrifuged and placed in a vacuum oven at 65℃ for 24 hours to obtain highly dispersible ultrafine copper powder.
[0063] The results are as described in 5-7. Figure 5 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 2 at low magnification. Figure 6 The image shows the SEM morphology of the ultrafine copper powder prepared in Example 2 at high magnification. It can be seen from the image that the copper particles have a smooth surface, good dispersibility, and are mostly regular spherical with a particle size distribution of about 250 nm. Figure 7 The image shows the XRD characterization results of the ultrafine copper powder prepared in Example 2.
[0064] Comparative Example 1
[0065] 10g of copper formate tetrahydrate was added to 50mL of water and sonicated for 5min at 120W. The mixture was then stirred for 10min at 60℃ and 500rpm to obtain an aqueous copper formate solution. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium chloride (CTAC) as dispersants, 4g of PVP and 2g of CTAC were dissolved in 20mL of water to obtain a PVP / CTAC mixed solution. This PVP / CTAC mixed solution was added to the copper formate aqueous solution and stirred for 10min at 500rpm to obtain a copper source-dispersant mixture. 6g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was added to the copper source-dispersant mixture and stirred for 5min at 500rpm. 15g of ascorbic acid was dissolved in 50mL of water to obtain an ascorbic acid solution, which was added to the above solution to obtain a cuprous oxide precursor solution. The cuprous oxide precursor solution was heated to 100°C and mechanically stirred at 500 rpm. The mixture was then refluxed at 100°C for 2 hours. After repeatedly washing the nano-copper particles with pure water and ethanol 3-5 times, the washed copper powder particles were centrifuged and placed in a vacuum oven at 65°C for 24 hours to obtain highly dispersible ultrafine copper powder.
[0066] The results are as follows Figure 8 As shown, Figure 8 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 1. It can be seen that the copper powder obtained without adding amine reagent to the reaction system has a large difference in morphology and uneven particle size distribution.
[0067] Comparative Example 2
[0068] 10g of copper formate tetrahydrate was mixed thoroughly with 8mL of isobutanolamine and stirred at 500rpm to obtain a complex of copper formate and isobutanolamine. 90mL of water was added to the complex, and the mixture was sonicated at 120W for 5 minutes, followed by stirring at 500rpm for 10 minutes to obtain an aqueous solution of the copper formate and isobutanolamine complex. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium chloride (CTAC) as dispersants, 4g of PVP and 2g of CTAC were dissolved in 40mL of water to obtain a PVP / CTAC mixed solution. This PVP / CTAC mixed solution was added to the aqueous solution of the copper formate and isobutanolamine complex and stirred at 500rpm for 10 minutes to obtain a copper source-dispersant mixture. 3g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was then added to the copper source-dispersant mixture and stirred at 500rpm for 5 minutes. Dissolve 15g of ascorbic acid in 50mL of water to obtain an ascorbic acid solution. Add this ascorbic acid solution to the above solution to obtain a cuprous oxide precursor solution. Heat the cuprous oxide precursor solution to 100℃ and mechanically stir at 500rpm. Reflux the solution at 100℃ for 2 hours. Wash the nano-copper particles repeatedly with pure water and ethanol 3-5 times. Then, vacuum dry the washed copper powder particles by centrifugation and place them in a vacuum oven at 65℃ for 24 hours to obtain highly dispersible ultrafine copper powder.
[0069] The results are as follows Figure 9 The above, Figure 9 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 2. It can be seen that when an alkaline solution is added to the system and the pH of the system is low, the copper powder has poor dispersibility.
[0070] Comparative Example 3
[0071] 10g of copper formate tetrahydrate and 8mL of isobutanolamine were mixed evenly and stirred at 500rpm to obtain a complex of copper formate and isobutanolamine. 90mL of water was added to the complex, and the mixture was sonicated at 120W for 5min, followed by stirring at 500rpm for 10min to obtain an aqueous solution of the copper formate and isobutanolamine complex. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium chloride (CTAC) as dispersants, 4g of PVP and 2g of CTAC were dissolved in 40mL of water to obtain a PVP / CTAC mixed solution. This PVP / CTAC mixed solution was added to the aqueous solution of the copper formate and isobutanolamine complex and stirred at 500rpm for 10min to obtain a copper source-dispersant mixture. 9g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was then added to the copper source-dispersant mixture and stirred at 500rpm for 5min. Dissolve 15g of ascorbic acid in 50mL of water to obtain an ascorbic acid solution. Add this ascorbic acid solution to the above solution to obtain a cuprous oxide precursor solution. Heat the cuprous oxide precursor solution to 100℃ and mechanically stir at 500rpm. Reflux the solution at 100℃ for 2 hours. Wash the nano-copper particles repeatedly with pure water and ethanol 3-5 times. Then, vacuum dry the washed copper powder particles by centrifugation and place them in a vacuum oven at 65℃ for 24 hours to obtain highly dispersible ultrafine copper powder.
[0072] The results are as follows Figure 10 The above, Figure 10 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 3. It can be seen that when an alkaline solution is added to the system and the pH of the system is high, the surface of the copper powder obtained is not smooth and the particle size distribution is uneven.
[0073] Comparative Example 4
[0074] 10g of copper formate tetrahydrate was mixed thoroughly with 8mL of isobutanolamine and stirred at 500rpm to obtain a complex of copper formate and isobutanolamine. 90mL of water was added to the complex, and the mixture was sonicated at 120W for 5 minutes, followed by stirring at 500rpm for 10 minutes to obtain an aqueous solution of the copper formate and isobutanolamine complex. Using polyvinylpyrrolidone (PVP) as a dispersant, 4g of PVP was dissolved in 40mL of water to obtain a PVP solution. This PVP solution was added to the aqueous solution of the copper formate and isobutanolamine complex and stirred at 500rpm for 10 minutes to obtain a copper source-dispersant mixture. 6g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was added to the copper source-dispersant mixture and stirred at 500rpm for 5 minutes. 15g of ascorbic acid was dissolved in 50mL of water to obtain an ascorbic acid solution, which was added to the above solution to obtain a cuprous oxide precursor solution. The cuprous oxide precursor solution was heated to 100°C and mechanically stirred at 500 rpm. The mixture was then refluxed at 100°C for 2 hours. After repeatedly washing the nano-copper particles with pure water and ethanol 3-5 times, the washed copper powder particles were centrifuged and placed in a vacuum oven at 65°C for 24 hours to obtain highly dispersible ultrafine copper powder.
[0075] The results are as follows Figure 11 The above, Figure 11 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 4. It can be seen that the copper powder obtained when polyvinylpyrrolidone (PVP) is used as a dispersant has pores and uneven particle size distribution.
[0076] Comparative Example 5
[0077] 10g of copper formate tetrahydrate was mixed thoroughly with 8mL of isobutanolamine and stirred at 500rpm to obtain a complex of copper formate and isobutanolamine. 90mL of water was added to the complex, and the mixture was sonicated at 120W for 5 minutes, followed by stirring at 500rpm for 10 minutes to obtain an aqueous solution of the copper formate and isobutanolamine complex. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants, 4g of PVP and 2g of CTAB were dissolved in 40mL of water to obtain a PVP / CTAB mixed solution. This PVP / CTAB mixed solution was added to the aqueous solution of the copper formate and isobutanolamine complex and stirred at 500rpm for 10 minutes to obtain a copper source-dispersant mixture. 6g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was then added to the copper source-dispersant mixture and stirred at 500rpm for 5 minutes. Dissolve 15g of ascorbic acid in 50mL of water to obtain an ascorbic acid solution. Add this ascorbic acid solution to the above solution to obtain a cuprous oxide precursor solution. Heat the cuprous oxide precursor solution to 100℃ and mechanically stir at 500rpm. Reflux the solution at 100℃ for 2 hours. Wash the nano-copper particles repeatedly with pure water and ethanol 3-5 times. Then, vacuum dry the washed copper powder particles by centrifugation and place them in a vacuum oven at 65℃ for 24 hours to obtain highly dispersible ultrafine copper powder.
[0078] result Figure 12 The above, Figure 12 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 5. It can be seen that the copper powder obtained by using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants has pores, large particle size, and uneven particle size distribution.
[0079] Comparative Example 6
[0080] 10g of copper acetate monohydrate and 8mL of isobutanolamine were mixed evenly and stirred at 500rpm to obtain a complex of copper acetate and isobutanolamine. 90mL of water was added to the complex, and the mixture was sonicated at 120W for 5min, followed by stirring at 500rpm for 10min to obtain an aqueous solution of the copper acetate-isobutanolamine complex. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants, 4g of PVP and 2g of CTAB were dissolved in 40mL of water to obtain a PVP / CTAB mixed solution. This PVP / CTAB mixed solution was added to the aqueous solution of the copper acetate-isobutanolamine complex and stirred at 500rpm for 10min to obtain a copper source-dispersant mixture. 6g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was then added to the copper source-dispersant mixture and stirred at 500rpm for 5min. Dissolve 15g of ascorbic acid in 50mL of water to obtain an ascorbic acid solution. Add this ascorbic acid solution to the above solution to obtain a cuprous oxide precursor solution. Heat the cuprous oxide precursor solution to 100℃ and mechanically stir at 500rpm. Reflux the solution at 100℃ for 2 hours. Wash the nano-copper particles repeatedly with pure water and ethanol 3-5 times. Then, vacuum dry the washed copper powder particles by centrifugation and place them in a vacuum oven at 65℃ for 24 hours to obtain highly dispersible ultrafine copper powder.
[0081] The results are as follows Figure 13 The above, Figure 13 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 6. It can be seen that the copper powder obtained by using copper acetate monohydrate as the copper source and polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants has large differences in morphology and uneven particle size distribution.
[0082] Comparative Example 7
[0083] 10g of copper acetate monohydrate was added to 100mL of water and sonicated for 5 minutes in a 120W ultrasonic system. The mixture was then stirred at 100℃ and 500rpm for 10 minutes to obtain an aqueous solution of copper acetate. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants, 4g of PVP and 2g of CTAB were dissolved in 40mL of water to obtain a PVP / CTAB mixed solution. This PVP / CTAB mixed solution was added to the copper acetate aqueous solution and stirred at 500rpm for 10 minutes to obtain a copper source-dispersant mixture. 6g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was then added to the copper source-dispersant mixture and stirred at 500rpm for 5 minutes. 15g of ascorbic acid was dissolved in 50mL of water to obtain an ascorbic acid solution, which was then added to the above solution to obtain a cuprous oxide precursor solution. The cuprous oxide precursor solution was heated to 100°C and mechanically stirred at 500 rpm. The mixture was then refluxed at 100°C for 2 hours. After repeatedly washing the nano-copper particles with pure water and ethanol 3-5 times, the washed copper powder particles were centrifuged and placed in a vacuum oven at 65°C for 24 hours to obtain highly dispersible ultrafine copper powder.
[0084] The results are as follows Figure 14 The above, Figure 14 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 7. It can be seen that without adding amine reagents to the reaction system, the copper powder obtained by using copper formate monohydrate as the copper source and polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants has large differences in morphology and uneven particle size distribution.
[0085] Comparative Example 8
[0086] 10g of copper sulfate pentahydrate was added to 50mL of water and sonicated for 5min at 120W. The mixture was then stirred for 10min at 60℃ and 500rpm to obtain an aqueous copper sulfate solution. Using polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants, 4g of PVP and 2g of CTAB were dissolved in 20mL of water to obtain a PVP / CTAB mixed solution. This PVP / CTAB mixed solution was added to the copper sulfate aqueous solution and stirred for 10min at 500rpm to obtain a copper source-dispersant mixture. 6g of sodium hydroxide was dissolved in 30mL of water to obtain a sodium hydroxide solution, which was then added to the copper source-dispersant mixture and stirred for 5min at 500rpm. 15g of ascorbic acid was dissolved in 50mL of water to obtain an ascorbic acid solution, which was then added to the above solution to obtain a cuprous oxide precursor solution. The cuprous oxide precursor solution was heated to 100°C and mechanically stirred at 500 rpm. The mixture was then refluxed at 100°C for 2 hours. After repeatedly washing the nano-copper particles with pure water and ethanol 3-5 times, the washed copper powder particles were centrifuged and placed in a vacuum oven at 65°C for 24 hours to obtain highly dispersible ultrafine copper powder.
[0087] The results are as follows Figure 15 The above, Figure 15 The image shows the SEM morphology of the ultrafine copper powder prepared in Comparative Example 8. It can be seen that without adding amine reagents to the reaction system, the copper powder obtained by using copper sulfate pentahydrate as the copper source and polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as dispersants has large differences in morphology and uneven particle size distribution.
Claims
1. A method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system, characterized in that, Includes the following steps: (1) Mix the copper source and amine reagent evenly, add deionized water and stir to dissolve to form a copper-amine complex solution; add a dispersant solution to the copper-amine complex solution and continue to stir and mix evenly to obtain a copper source-dispersant mixed solution; (2) The copper source-dispersant mixed solution obtained in step (1) and the aqueous solution of reducing agent are mixed and reacted to obtain cuprous oxide precursor; (3) The cuprous oxide precursor solution obtained in step (2) is transferred to an oil bath reaction apparatus and refluxed at 80℃-120℃ for 0.5~4h. During the reaction, the mixture is continuously stirred at 300~600rpm. The cuprous oxide is reduced twice to generate ultrafine copper powder. After the reaction is completed, the product is washed, centrifuged and dried to obtain highly dispersed ultrafine copper powder.
2. The method and process for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system according to claim 1, characterized in that, The copper source in step (1) includes one or more of copper sulfate pentahydrate, copper nitrate, copper chloride, copper formate tetrahydrate, and copper acetate monohydrate.
3. The method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system according to claim 1, characterized in that, The amine reagent in step (1) includes one or more of isopropanolamine, isobutanolamine, triethanolamine, ethanolamine and propanolamine.
4. The method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system according to claim 1, characterized in that, The dispersant in step (1) includes one or more of gelatin, gum arabic, polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide and hexadecyltrimethyl-p-toluenesulfonate.
5. The method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system according to claim 1, characterized in that, In step (2), the copper source-dispersant mixed solution and the reducing agent aqueous solution are mixed and then mixed with an alkaline solution; the alkaline solution includes one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.
6. The method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system according to claim 5, characterized in that, The reducing agent in step (2) includes one or more of sodium borohydride, sodium hypophosphite, glucose, formaldehyde, hydrazine hydrate, hydrogen peroxide, L-ascorbic acid, lithium borohydride, thiourea dioxide, potassium borohydride, and ferrous citrate.
7. The method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system according to claim 1, characterized in that, In steps (1) and (2), the molar ratio of copper source to amine reagent is 0.1~2.0:1, the concentration of copper-containing solution is 0.1~3 mol / L, the concentration of dispersant solution is 0.001-1 mol / L, and the molar ratio of reducing agent in reducing agent solution to copper ions in copper-containing solution is 0.1~2.0:1; the volume ratio of copper-containing solution, dispersant solution and reducing agent solution is 80~120:30~60:40~60.
8. The method for preparing highly dispersed ultrafine copper powder using an aqueous copper-amine complex system according to claim 7, characterized in that, The concentration of the alkaline solution is 0~10mol / L, and the volume ratio of the copper-containing solution, dispersant solution, alkaline solution and reducing agent solution is 80~120:30~60:20~40:40~60.
9. The preparation method according to claim 1, characterized in that, In step (3), the reaction temperature is 80-120℃, the reaction time is 0.5-4h, and the reaction is accompanied by stirring at a speed of 300-600rpm.
10. Copper particles obtained by the preparation method according to any one of claims 1 to 9.