Surface-modified copper nanopowder, method of making and use thereof

Abstract

The present application relates to a kind of surface modification nano copper powder and preparation method and application, surface modification nano copper powder includes nano copper powder, and surface modifier is uniformly distributed on the outer surface of nano copper powder matrix, the chemical bond between the nano copper powder and the surface modifier is combined, and the surface modifier is azide compound.Nano copper powder dispersion liquid is added to surface modifier solution while stirring, and after stirring to mix evenly, continue stirring, so that complexation reaction of azide functional group of nano copper powder and surface modifier occurs and forms coordination bond, after reaction, its solid material is obtained by centrifugation or filtration;The above solid material is freeze-dried, and sealed storage is obtained, and the surface modification nano copper powder finished product is obtained;The surface modifier is azide compound.Compared with prior art, the present application can simultaneously have excellent antioxidant and dispersibility and other advantages.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of nano metal powder, in particular to surface-modified nano copper powder and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of AI (artificial intelligence) and the demand for huge computing power, high-performance computing chips are more integrated, and interconnections are multi-layer stacked, especially the interconnections of HBM (high bandwidth memory) and high-density Z-direction PCB (printed circuit) boards, which put forward higher requirements on the size and performance of conductive materials. Copper powder is an important conductive material for electronic interconnection at present, and the copper powder used at present is mainly micron powder, which cannot meet the demand of high-density interconnection. High-purity nano copper powder has the advantages of low sintering temperature, low softening temperature, high specific surface, high electrical conductivity and thermal conductivity, and is a key material for the development of the next generation of electronic interconnection. However, nano metal, especially nano copper powder, is easy to oxidize and agglomerate, which seriously affects its actual application. Therefore, it is necessary to solve the problems of oxidation and dispersion of high-purity nano copper powder. High-purity nano copper powder is a new type of low-melting-point and high-conductivity electronic interconnection key material, which can meet the demand of the electronic industry for high-performance conductive materials under complex working conditions.

[0003] Patent No. CN101011747A discloses a method for manufacturing copper powder and copper powder. Under the protection of the colloid, water-soluble copper salt is added to prepare copper powder with a purity of 99.9% and a particle size distribution of 0.2-1 mu m by mixing cuprous oxide with a reducing agent. However, the size is still large; the preparation method of nano copper powder disclosed in patent Nos. CN102896322A and CN101608077A controls the size to be 20-100 nm and 20-70 nm, but the purity is low; and the particle size of the copper powder of the nano copper paste disclosed in patent No. CN111975011A is a bimodal distribution (large particles of 120-200 nm and small particles of 5-20 nm), resulting in a high sintering temperature (260-300 DEG C). Nano copper powder is easy to oxidize and has poor dispersibility (i.e. easy to agglomerate). Research shows that high-purity nano metal has excellent anti-oxidation properties. The surface-modified flaky nano copper disclosed in patent No. CN106479599A is surface-modified by using stearic acid, stearate, oleic acid and DDP, etc. The size of the flaky nano copper powder is 10-20 nm, but the types of additives are too many and complex, and only the flaky sample is mentioned, and the spherical powder with a larger surface area and higher modification difficulty is not mentioned. In addition, there is no nano copper powder modification with specific functional group organic matter at present, so it is urgent to obtain nano copper powder with excellent anti-oxidation properties and dispersibility and a preparation method thereof. SUMMARY

[0004] The present application aims to overcome the defects of the prior art and provides a surface-modified nano-copper powder, a preparation method and an application, which can simultaneously have excellent oxidation resistance and dispersibility.

[0005] The object of the present application can be achieved by the following technical solutions.

[0006] One of the technical solutions of the present application is to provide a surface-modified nano-copper powder, which comprises nano-copper powder and a surface modifier uniformly distributed on the outer surface of the nano-copper powder matrix, wherein the nano-copper powder and the surface modifier are combined by a chemical bond, and the surface modifier is an azide compound.

[0007] Further, the azide compound is a non-acidic organic compound containing an azide functional group, including ethyl azidoacetate, azido-PEG4-amine, 3-azidopropylamine, and azido-PEG-amine.

[0008] Further, the original particle size of the nano-copper powder is 5-500 nm, and the purity is greater than 99.99%.

[0009] Further, the original particle size of the nano-copper powder is 10-200 nm.

[0010] Further, the particle size of the surface-modified nano-copper powder is smaller than the original particle size of the nano-copper powder, and the particle size of the surface-modified nano-copper powder is 5-200 nm, preferably 5-100 nm, and more preferably 5-50 nm.

[0011] Further, the preparation method of the nano-copper powder includes liquid phase reduction method, atomization method, electrodeposition method and physical vapor deposition method, and the liquid phase reduction method is preferred.

[0012] Further, the preparation process of the liquid phase reduction method is as follows: drop the sodium hydroxide-ethylene glycol solution into the polyvinylpyrrolidone-copper salt-ethylene glycol solution, control the pH at 8-11, mix uniformly to obtain a precursor solution; place it in a high-pressure reaction kettle, heat to 120-140℃, the stirring speed is 300-800 r / min, the hydrogen pressure is 1-5 MPa, and the reaction is carried out for 1-10 h to obtain an ethylene glycol solution containing nano-copper powder, and the solid material obtained by centrifugal separation is nano-copper powder. Ethylene glycol as an organic solvent can be replaced by other common organic solvents.

[0013] Further, the prepared nano-copper powder is washed with anhydrous ethanol or acetone.

[0014] Further, the concentration of the alkali metal organic solution is 0.1-0.5 mol / L, the mass ratio of polyvinylpyrrolidone, copper salt and ethylene glycol in the polyvinylpyrrolidone-copper salt-ethylene glycol solution is 10-30:0.1-0.5:20-60, and the copper salt is copper sulfate pentahydrate.

[0015] Further, the ultrasonic treatment time is 3-5 min, the centrifugal separation speed is 6500 r / min-9200 r / min, and the centrifugal separation time is 3-20 min.

[0016] Further, the molar ratio of the nano-copper powder to the surface modifier is 1:(1-8).

[0017] Further, the related parameters of the electrodeposition method are as follows: current is 2-8 A, voltage is 15-25 V, duty cycle is 10%-30%, and the power-on time is 1-10 min, so that the nano-copper powder with a purity of 99.99% and a size of 155-300 nm is obtained.

[0018] The second technical solution of the present application provides a preparation method of surface-modified nano-copper powder, comprising the following steps:

[0019] The nano-copper powder dispersion liquid is added into the surface modifier solution while stirring, and after uniform mixing, the stirring is continued to make the azide functional groups of the nano-copper powder and the surface modifier form complexation to form a coordination bond, and after the reaction is completed, the solid material is obtained by centrifugation or filtration;

[0020] The above solid material is subjected to freeze-drying treatment and sealed storage to obtain the surface-modified nano-copper powder finished product.

[0021] The surface modifier is an azide compound.

[0022] Further, the nano-copper powder dispersion liquid disperses the nano-copper powder into an organic solvent, and the organic solvent includes anhydrous ethanol or acetone.

[0023] Further, the concentration of the surface modifier is (3-20)×10 -5 mol / L, the solute is an azide compound, and the solvent is anhydrous ethanol.

[0024] Further, the molar ratio of the nano-copper powder in the nano-copper powder dispersion liquid to the surface modifier in the surface modifier solution is 1:(1-8).

[0025] Further, the reaction temperature of the azide functional groups of the nano-copper powder and the surface modifier is room temperature, and the reaction time is 0.5-6 h.

[0026] Further, the nano-copper powder is cleaned with anhydrous ethanol or acetone before use, and the cleaning method adopts ultrasonic and centrifugal methods commonly used in the art.

[0027] Further, the freeze-drying treatment temperature is-50--30℃, and the freeze-drying treatment time is 8-20 h.

[0028] Further, the sealed storage is by Ar, N2 or vacuum sealing.

[0029] Further, the solid substance is washed and then subjected to freeze-drying treatment, and the washing liquid includes anhydrous ethanol and water.

[0030] The third technical scheme of the present application provides an application of the surface-modified nano copper powder, and the surface-modified nano copper powder is used for preparing electronic interconnection paste and lubricating grease wear-resistant additives.

[0031] Further, the sealed storage is by Ar, N2 or vacuum sealing.

[0032] The third technical scheme of the present application provides an application of the surface-modified nano copper powder, and the surface-modified nano copper powder is used for preparing electronic interconnection paste and lubricating grease wear-resistant additives.

[0033] Compared with the prior art, the present application has the following advantages:

[0034] (1) The present application introduces azide compounds with excellent activity, and controls the distribution of the azide compounds on the surface of the copper powder, forms stable copper-azide functional group bonds, effectively reduces the problem of easy agglomeration of the nano copper powder itself caused by high free energy and high surface area, improves the purity of the copper particles by controlling the purity of the copper powder, and further reduces the oxidation of the copper powder surface.

[0035] (2) The present application uses azide compounds with different linking groups and containing azide functional groups as surface modifiers to modify the nano copper powder, controls the hydrophilic or lipophilic linking groups (and different types of azide compounds), and further obtains nano copper powder with excellent hydrophilic or lipophilic properties, while enhancing the oxidation resistance and anti-agglomeration performance of the nano copper powder, greatly improving the dispersibility of the nano copper powder in electronic interconnection paste and lubricating grease, and further improving the application efficiency of the electronic interconnection paste or grease.

[0036] (3) The preparation method of the surface-modified nano copper powder provided by the present application is simple in operation, short in process, low in cost and good in modification effect. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The infrared spectrum of the surface-modified nano copper powder product of Example 1 and the unmodified nano copper powder of Comparative Example 1 and ethyl azide acetate;

[0038] Figure 2 The TEM image of the surface-modified nano copper powder product of Example 1;

[0039] Figure 3 The TEM image of the surface-modified nano copper powder product of Example 2;

[0040] Figure 4 The infrared spectrogram of the surface-modified nano-copper powder product of Example 3, the unmodified nano-copper powder of Comparative Example 1 and azido-PEG-4;

[0041] Figure 5 The thermogravimetric analysis chart of the unmodified nano-copper powder of Comparative Example 1 and the surface-modified nano-copper powder product of Example 7;

[0042] Figure 6 The TEM chart of the unmodified nano-copper powder of Comparative Example 1;

[0043] Figure 7 The TEM chart of the unmodified nano-copper powder of Comparative Example 2;

[0044] Figure 8 The thermogravimetric analysis chart of the unmodified nano-copper powder of Comparative Example 3 and the surface-modified nano-copper powder product of Example 3;

[0045] Figure 9 The TEM chart of the unmodified nano-copper powder of Comparative Example 2.

[0046] Figure 10 The SEM chart of the unmodified nano-copper powder of Comparative Example 3. DETAILED DESCRIPTION

[0047] The present application will be described in detail below with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical solution of the present application, and gives a detailed implementation and specific operation process, but the protection scope of the present application is not limited to the following examples. All other examples obtained by those skilled in the art on the premise that no creative labor is done based on the given examples, all belong to the scope of protection of the present application.

[0048] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present application are conventional reagents, methods, instruments and equipment in the art.

[0049] In the following examples, the molecular formula of ethyl azidoacetate is C4H7N3O2, the CAS number is 637-81-0, and the purity is ≥95%; the molecular formula of azido-PEG-4 amine is C10H22N4O4, the CAS number is 951671-92-4, and the purity is ≥95%; the molecular formula of polyvinylpyrrolidone K30 is (C6H9NO) n , the CAS number is 84057-81-8, and the 20% solution; the molecular formula of 3-azidopropylamine is C3H8N4, the CAS number is 88192-19-2, and the purity is ≥95%; the molecular formula of azido-PEG-amine is N3-PEG-NH2, the purity is ≥95%, and the MW is 2000 Da. All are purchased from Shanghai Aladdin Biochem Technology Co., Ltd.

[0050] A surface-modified nano-copper powder comprises nano-copper powder and a surface modifier uniformly distributed on the outer surface of the nano-copper powder matrix, the nano-copper powder and the surface modifier are combined by chemical bonds, and the surface modifier is an azide compound.

[0051] As one of the preferred embodiments, the azide compound is a non-acidic organic compound containing an azide functional group, including ethyl azide acetate, azido-PEG4-amine, 3-azido propylamine, and azido-PEG-amine.

[0052] As one of the preferred embodiments, the original particle size of the nano-copper powder is 5-500 nm, and the purity is greater than 99.99%.

[0053] As one of the preferred embodiments, the original particle size of the nano-copper powder is 10-200 nm.

[0054] As one of the preferred embodiments, the particle size of the surface-modified nano-copper powder is smaller than the original particle size of the nano-copper powder, and the particle size of the surface-modified nano-copper powder is 5-200 nm, preferably 5-100 nm, and more preferably 5-50 nm.

[0055] As one of the preferred embodiments, the preparation method of the nano-copper powder includes liquid phase reduction method, atomization method, electrodeposition method, and physical vapor deposition method, and the liquid phase reduction method is preferred.

[0056] As one of the preferred embodiments, the preparation process of the liquid phase reduction method is as follows: sodium hydroxide-ethylene glycol solution is added dropwise into polyvinylpyrrolidone-copper salt-ethylene glycol solution, the pH is controlled at 8-11, and the mixture is uniformly obtained to obtain a precursor solution; the precursor solution is placed in a high-pressure reaction kettle, heated to 120-140℃, the stirring speed is 300-800 r / min, the hydrogen pressure is 1-5 MPa, and the reaction is carried out for 1-10 h to obtain an ethylene glycol solution containing nano-copper powder, and the solid material obtained by centrifugal separation is nano-copper powder. Ethylene glycol as an organic solvent can be replaced by other common organic solvents.

[0057] As one of the preferred embodiments, the prepared nano-copper powder is washed with anhydrous ethanol.

[0058] As one of the preferred embodiments, the concentration of the alkali metal organic solution is 0.1-0.5 mol / L, the mass ratio of polyvinylpyrrolidone, copper salt, and ethylene glycol in the polyvinylpyrrolidone-copper salt-ethylene glycol solution is 10-30:0.1-0.5:20-60, and the copper salt is copper sulfate pentahydrate.

[0059] As one of the preferred embodiments, the ultrasonic treatment time is 3-5 min, the centrifugal separation speed is 6500 r / min-9200 r / min, and the centrifugal separation time is 3-20 min.

[0060] As one of the preferred embodiments, the molar ratio of the nano-copper powder to the surface modifier is 1:(1-8).

[0061] As one of the preferred embodiments, the relevant parameters of the electrodeposition method are as follows: the current is 2-8 A, the voltage is 15-25 V, the duty cycle is 10%-30%, and the power-on time is 1-10 min, to obtain nano-copper powder with a purity of 99.99% and a size of 155-300 nm.

[0062] A preparation method of surface-modified nano-copper powder comprises the following steps:

[0063] The nano-copper powder dispersion liquid is added into the surface modifier solution while stirring, and after stirring until uniform mixing, the stirring is continued to allow the azide functional groups of the nano-copper powder and the surface modifier to undergo complexation reaction to form coordination bonds, and after the reaction is completed, the solid material is obtained by centrifugation or filtration;

[0064] The above solid material is subjected to freeze-drying treatment and sealed for storage, to obtain the finished surface-modified nano-copper powder.

[0065] The surface modifier is an azide compound.

[0066] As one of the preferred embodiments, the nano-copper powder dispersion liquid disperses the nano-copper powder into an organic solvent, and the organic solvent includes anhydrous ethanol or acetone.

[0067] As one of the preferred embodiments, the concentration of the surface modifier is (3-20)×10 -5 mol / L, the solute is an azide compound, and the solvent is anhydrous ethanol.

[0068] As one of the preferred embodiments, the molar ratio of the nano-copper powder in the nano-copper powder dispersion liquid to the surface modifier in the surface modifier solution is 1:(1-8).

[0069] As one of the preferred embodiments, the reaction temperature of the azide functional groups of the nano-copper powder and the surface modifier is room temperature, and the reaction time is 0.5-6 h.

[0070] As one of the preferred embodiments, the nano-copper powder is cleaned with anhydrous ethanol or acetone before use, and the cleaning method uses ultrasonic and centrifugal methods commonly used in the field.

[0071] As one of the preferred embodiments, the freeze-drying treatment temperature is -50 to -30°C, and the freeze-drying treatment time is 8-20 h.

[0072] As one of the preferred embodiments, the sealed storage is by Ar, N2 or vacuum sealing.

[0073] As one of the preferred embodiments, the solid substance is washed and then subjected to freeze-drying treatment, and the washing liquid includes anhydrous ethanol, water.

[0074] The application of surface-modified nano-copper powder in the preparation of electronic interconnection paste and lubricating grease wear-resistant additive.

[0075] As one of the preferred embodiments, the sealed storage is by Ar, N2 or vacuum sealing.

[0076] The application of surface-modified nano-copper powder in the preparation of electronic interconnection paste and lubricating grease wear-resistant additive.

[0077] Example 1

[0078] The present application provides a kind of surface-modified nano-copper powder and preparation method, its preparation method includes the following steps:

[0079] (1) surface modifier organic solvent A preparation:

[0080] 18 μL of ethyl azidoacetate is placed in 20 ml of anhydrous ethanol, stirred for 10 min to obtain solution A.

[0081] (2) nano-copper powder preparation:

[0082] 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate are dissolved in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; sodium hydroxide is dissolved in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and 35 mL of the sodium hydroxide-ethylene glycol solution is added dropwise to the above polyvinylpyrrolidone-copper salt-ethylene glycol solution, and mixed uniformly to obtain a precursor solution. It is placed in a high-pressure reaction kettle, heated to 130℃, the stirring speed is 500 r / min, the hydrogen pressure is 2 MPa, and the reaction is carried out for 3 h to obtain an ethylene glycol solution containing nano-copper powder. Centrifugal separation is carried out, and the obtained solid substance is nano-copper powder, which is then washed with anhydrous ethanol 3 times. The prepared nano-copper powder has a copper purity of 99.99% and a particle size of 10-50 nm.

[0083] (3) surface modification treatment of nano-copper powder:

[0084] Put 0.2 g of the above-mentioned cleaned nano-copper powder into 200 mL of anhydrous ethanol to obtain a nano-copper powder dispersion (dispersion B), and then gradually add 200 mL of the dispersion B into solution A at a stirring rate of 300 r / min, wherein the molar ratio of the nano-copper powder and ethyl azidoacetate is 1:8; after stirring until uniform, continue stirring for 0.5 h to allow the complexation reaction between the nano-copper powder and the azido functional groups of the surface modifier to form coordination bonds, and then perform centrifugal separation at a speed of 9200 r / min for 10 min to obtain a solid surface-modified nano-copper powder semi-finished product.

[0085] (4) Storage of the surface-modified nano-copper powder finished product:

[0086] Clean the surface-modified nano-copper powder semi-finished product with anhydrous ethanol for 2 times, with ultrapure water for 1 time, freeze-dry at -40℃ for 20 h, and store in Ar to obtain the surface-modified nano-copper powder finished product.

[0087] Example 2

[0088] The present application provides a surface-modified nano-copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0089] (1) Preparation of the surface modifier organic solvent A:

[0090] Put 25 μL of ethyl azidoacetate into 20 mL of anhydrous ethanol, and stir for 10 min to obtain solution A.

[0091] (2) Preparation of the nano-copper powder:

[0092] Dissolve 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; dissolve sodium hydroxide in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and then add 35 mL of the sodium hydroxide-ethylene glycol solution dropwise into the above-mentioned polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. Place the precursor solution in a high-pressure reaction kettle, heat to 140℃, and stir at a speed of 500 r / min under a hydrogen pressure of 2 MPa for 3 h to obtain an ethylene glycol solution containing nano-copper powder, and then perform centrifugal separation to obtain a solid nano-copper powder, which is then cleaned with anhydrous ethanol for 3 times. The prepared nano-copper powder has a copper purity of 99.99% and a particle size of 30-50 nm.

[0093] (3) Surface modification treatment of the nano-copper powder:

[0094] Put 0.2 g of the above-mentioned cleaned nano-copper powder into 200 mL of acetone to obtain a nano-copper powder dispersion (dispersion B), and then gradually add 200 mL of the dispersion B into solution A at a stirring rate of 300 r / min, wherein the molar ratio of the nano-copper powder and ethyl azidoacetate is 1:5.53; after stirring until uniform, continue to stir for 2 h to allow the complexation reaction between the nano-copper powder and the azido functional groups of the surface modifier to form coordination bonds, and then perform centrifugal separation at a speed of 9200 r / min for 10 min to obtain a solid surface-modified nano-copper powder semi-finished product.

[0095] (4) Storage of the surface-modified nano-copper powder finished product:

[0096] Clean the surface-modified nano-copper powder semi-finished product with anhydrous ethanol for 2 times, clean with ultrapure water for 1 time, freeze-dry at -40℃ for 10 h, seal with N2, and obtain the surface-modified nano-copper powder finished product.

[0097] Example 3

[0098] The present application provides a surface-modified nano-copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0099] (1) Preparation of the surface modifier organic solvent A:

[0100] Put 60 μL of azido-PEG-4 amine into 20 mL of anhydrous ethanol, and stir for 10 min to obtain solution A.

[0101] (2) Preparation of the nano-copper powder:

[0102] Dissolve 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; dissolve sodium hydroxide in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and then add 35 mL of the sodium hydroxide-ethylene glycol solution to the above-mentioned polyvinylpyrrolidone-copper salt-ethylene glycol solution dropwise to obtain a precursor solution. Place the precursor solution in a high-pressure reaction kettle, heat to 130℃, and stir at a speed of 500 r / min under a hydrogen pressure of 2 MPa for 3 h to obtain an ethylene glycol solution containing nano-copper powder, and then perform centrifugal separation to obtain a solid nano-copper powder, and then clean the solution with anhydrous ethanol for 3 times. The prepared nano-copper powder has a copper purity of 99.99% and a particle size of 10-50 nm.

[0103] (3) Surface modification treatment of the nano-copper powder:

[0104] The 0.2 g of the above cleaned nano-copper powder is placed in 200 mL of anhydrous ethanol to obtain a nano-copper powder dispersion (dispersion B), and 300 mL of the dispersion B is gradually added to the solution A at a stirring rate of 300 r / min, wherein the molar ratio of the nano-copper powder and the azido-PEG-4 amine is 1:4.77; after stirring until uniform, the stirring is continued for 1 h to allow the complexation reaction of the nano-copper powder and the azido functional groups of the surface modifier to form coordination bonds, and after the reaction is completed, centrifugal separation is performed at a speed of 8000 r / min for 15 min to obtain a solid surface-modified nano-copper powder semi-finished product.

[0105] (4) Storage of the surface-modified nano-copper powder finished product:

[0106] The surface-modified nano-copper powder semi-finished product is cleaned with anhydrous ethanol for 2 times, cleaned with ultrapure water for 1 time, freeze-dried at -40℃ for 8 h, sealed with Ar, and stored to obtain the surface-modified nano-copper powder finished product.

[0107] Example 4

[0108] The present application provides a surface-modified nano-copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0109] (1) Preparation of the surface modifier organic solvent A:

[0110] 25 μL of 3-azidopropylamine is placed in 20 mL of anhydrous ethanol and stirred for 10 min to obtain the solution A.

[0111] (2) Preparation of the nano-copper powder:

[0112] 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate are dissolved in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; sodium hydroxide is dissolved in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and 35 mL of the sodium hydroxide-ethylene glycol solution is added dropwise into the above polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. The precursor solution is placed in a high-pressure reaction kettle, heated to 130℃, and stirred at a speed of 500 r / min, and the hydrogen pressure is 1.5 MPa, and the reaction is carried out for 3 h to obtain an ethylene glycol solution containing nano-copper powder, and the obtained solid material is nano-copper powder, which is then cleaned with anhydrous ethanol for 3 times. The prepared nano-copper powder has a copper purity of 99.99% and a particle size of 30-100 nm.

[0113] (3) Surface modification treatment of the nano-copper powder:

[0114] Put 0.2 g of the above-mentioned cleaned nano-copper powder into 200 mL of anhydrous ethanol to obtain a nano-copper powder dispersion (dispersion B), and take 300 mL of the dispersion B and gradually add it into solution A at a stirring rate of 300 r / min, wherein the molar ratio of the nano-copper powder and 3-azido-propylamine is 1:5.6; after stirring until uniform, continue stirring for 1 h to allow the complexation reaction of the nano-copper powder and the azido functional groups of the surface modifier to form coordination bonds, and after the reaction is completed, centrifugal separation is performed at a speed of 8000 r / min for 15 min to obtain a solid surface-modified nano-copper powder semi-finished product.

[0115] (4) Storage of the surface-modified nano-copper powder finished product:

[0116] Clean the surface-modified nano-copper powder semi-finished product with anhydrous ethanol for 2 times, clean it with ultrapure water for 1 time, freeze-dry at -40℃ for 10 h, seal with Ar, and obtain the surface-modified nano-copper powder finished product.

[0117] It is measured that the surface-modified nano-copper powder finished product has excellent dispersibility, no oxidation on the surface, and a particle size of 15-25 nm.

[0118] Example 5

[0119] The present application provides a surface-modified nano-copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0120] (1) Preparation of the surface modifier organic solvent A:

[0121] Put 25 μL of azido-PEG-amine into 20 mL of anhydrous ethanol and stir for 10 min to obtain solution A.

[0122] (2) Preparation of the nano-copper powder:

[0123] Dissolve 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; dissolve sodium hydroxide in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and take 35 mL of the sodium hydroxide-ethylene glycol solution and drop it into the above-mentioned polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. Place it in a high-pressure reaction kettle, heat to 130℃, the stirring speed is 500 r / min, the hydrogen pressure is 1.5 MPa, and the reaction is carried out for 3.5 h to obtain an ethylene glycol solution containing nano-copper powder, and the obtained solid material is nano-copper powder after centrifugal separation, and then the solution is cleaned with anhydrous ethanol for 3 times. The prepared nano-copper powder has a copper purity of 99.99% and a particle size of 30-100 nm.

[0124] (3) Surface modification treatment of the nano-copper powder:

[0125] 0.2 g of the above-mentioned washed nanometer copper powder was placed in 200 mL of anhydrous ethanol to obtain a nanometer copper powder dispersion (dispersion B), and 300 mL of the dispersion B was gradually added to solution A while stirring at a rate of 300 r / min, wherein the molar ratio of nanometer copper powder and 3-azidopropylamine was 1:5.6; after stirring until uniform, the stirring was continued for 1 h to allow the complexation reaction between the nanometer copper powder and the azide functional groups of the surface modifier to form coordination bonds, and after the reaction was completed, centrifugal separation was performed at a speed of 8000 r / min for 15 min to obtain a solid surface-modified nanometer copper powder semi-finished product.

[0126] (4) Storage of the surface-modified nanometer copper powder finished product:

[0127] The surface-modified nanometer copper powder semi-finished product was washed twice with anhydrous ethanol and once with ultrapure water, and was freeze-dried at -40℃ for 10 h, sealed with Ar, and stored to obtain the surface-modified nanometer copper powder finished product.

[0128] It was measured that the surface-modified nanometer copper powder finished product had excellent dispersibility, no oxidation on the surface, and a particle size of 15-25 nm.

[0129] Example 6

[0130] The present application provides a surface-modified nanometer copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0131] (1) Preparation of surface modifier organic solvent A:

[0132] 25 μL of 3-azidopropylamine was placed in 20 mL of anhydrous ethanol and stirred for 10 min to obtain solution A.

[0133] (2) Preparation of nanometer copper powder:

[0134] 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate were dissolved in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; sodium hydroxide was dissolved in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and 35 mL of the sodium hydroxide-ethylene glycol solution was added dropwise to the above-mentioned polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. The precursor solution was placed in a high-pressure reaction kettle, heated to 120℃, and stirred at a speed of 500 r / min under a hydrogen pressure of 1.5 MPa for 3 h to obtain an ethylene glycol solution containing nanometer copper powder, and the solid material obtained after centrifugal separation was nanometer copper powder, which was then washed with anhydrous ethanol three times. The nanometer copper powder prepared had a copper purity of 99.99% and a particle size of 8-50 nm.

[0135] (3) Surface modification treatment of nanometer copper powder:

[0136] 0.2 g of the above-mentioned cleaned nano-copper powder was placed in 200 mL of anhydrous ethanol to obtain a nano-copper powder dispersion (dispersion B), and 300 mL of the dispersion B was gradually added to solution A while stirring at a rate of 300 r / min, wherein the molar ratio of the nano-copper powder and 3-azido-propylamine was 1:5.6; after stirring until uniform, the stirring was continued for 1 h to allow the complexation reaction between the nano-copper powder and the azido functional groups of the surface modifier to form coordination bonds, and after the reaction was completed, centrifugal separation was performed at a speed of 6500 r / min for 20 min to obtain a solid surface-modified nano-copper powder semi-finished product.

[0137] (4) Storage of the surface-modified nano-copper powder finished product:

[0138] The surface-modified nano-copper powder semi-finished product was cleaned with anhydrous ethanol for 2 times, cleaned with ultrapure water for 1 time, freeze-dried at -40℃ for 10 h, sealed with Ar, and stored to obtain the surface-modified nano-copper powder finished product.

[0139] It was measured that the surface-modified nano-copper powder finished product had excellent dispersibility, no oxidation on the surface, and a particle size of 5-25 nm.

[0140] Example 7

[0141] The present application provides a surface-modified nano-copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0142] (1) Preparation of the surface modifier organic solvent A:

[0143] 250 μL of ethyl azidoacetate was placed in 20 mL of anhydrous ethanol and stirred for 10 min to obtain solution A.

[0144] (2) Preparation of the nano-copper powder:

[0145] 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate were dissolved in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; sodium hydroxide was dissolved in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and 35 mL of the sodium hydroxide-ethylene glycol solution was added dropwise to the above-mentioned polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. The precursor solution was placed in a high-pressure reaction kettle, heated to 130℃, and stirred at a speed of 500 r / min under a hydrogen pressure of 2 MPa for 3 h to obtain an ethylene glycol solution containing nano-copper powder, and the obtained solid material was nano-copper powder after centrifugal separation, and the solution was then cleaned with anhydrous ethanol for 3 times. The prepared nano-copper powder had a copper purity of 99.99% and a particle size of 10-50 nm.

[0146] (3) Surface modification treatment of the nano-copper powder:

[0147] The 0.2 g of the above-mentioned cleaned nano-copper powder is placed in 200 mL of anhydrous ethanol to obtain a nano-copper powder dispersion (dispersion B), and 100 mL of the dispersion B is gradually added to the solution A at a stirring rate of 300 r / min, wherein the molar ratio of the nano-copper powder and the ethyl azidoacetate is 1:1; after stirring until uniform mixing, the stirring is continued for 0.5 h to allow the complexation reaction of the nano-copper powder and the azido functional group of the surface modifier to form a coordination bond, and after the reaction is completed, centrifugal separation is performed at a speed of 8500 r / min for 10 min to obtain a solid surface-modified nano-copper powder semi-finished product.

[0148] (4) Surface-modified nano-copper powder finished product storage:

[0149] The surface-modified nano-copper powder semi-finished product is washed with anhydrous ethanol for 2 times, washed with ultrapure water for 1 time, freeze-dried at -40℃ for 10 h, sealed with Ar, and the surface-modified nano-copper powder finished product is obtained.

[0150] Example 8

[0151] The present application provides a surface-modified nano-copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0152] (1) Preparation of surface modifier organic solvent A:

[0153] 8 μL of ethyl azidoacetate is placed in 20 mL of anhydrous ethanol and stirred for 10 min to obtain solution A.

[0154] (2) Preparation of nano-copper powder:

[0155] Nano-copper powder with a purity of 99.99% and a particle size of 52-103 nm is purchased from Shanghai Mao Gu Nano Technology Co., Ltd., and the nano-copper powder is washed with anhydrous ethanol for 3 times.

[0156] (3) Surface modification treatment of nano-copper powder:

[0157] The 0.2 g of the above-mentioned cleaned nano-copper powder is placed in 200 mL of anhydrous ethanol to obtain a nano-copper powder dispersion (dispersion B), and 100 mL of the dispersion B is gradually added to the solution A at a stirring rate of 300 r / min, wherein the molar ratio of the nano-copper powder and the ethyl azidoacetate is 1:1; after stirring until uniform mixing, the stirring is continued for 0.5 h to allow the complexation reaction of the nano-copper powder and the azido functional group of the surface modifier to form a coordination bond, and after the reaction is completed, centrifugal separation is performed at a speed of 8500 r / min for 10 min to obtain a solid surface-modified nano-copper powder semi-finished product.

[0158] (4) Surface-modified nano-copper powder finished product storage:

[0159] The surface-modified nano-copper powder semi-product is washed twice with anhydrous ethanol and once with ultrapure water, and is subjected to freeze-drying treatment at -40°C for 10 h, and is stored in Ar.

[0160] The surface-modified nano-copper powder product has good dispersibility, and the copper powder has a particle size of 43-85 nm.

[0161] Example 9

[0162] The present application provides a surface-modified nano-copper powder and a preparation method thereof, and the preparation method comprises the following steps:

[0163] (1) Preparation of a surface modifier organic solvent A:

[0164] 50 μL of ethyl azidoacetate is placed in 20 ml of anhydrous ethanol, and is stirred for 10 min to obtain solution A.

[0165] (2) Preparation of nano-copper powder:

[0166] 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate are dissolved in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; sodium hydroxide is dissolved in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and 35 mL of the sodium hydroxide-ethylene glycol solution is added dropwise into the polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. The precursor solution is placed in a high-pressure reaction kettle, and is heated to 130°C, with a stirring speed of 500 r / min and a hydrogen pressure of 2 MPa, and is reacted for 3 h to obtain an ethylene glycol solution containing nano-copper powder. The nano-copper powder is obtained by centrifugal separation of the solid material, and the nano-copper powder is washed with anhydrous ethanol three times. The prepared nano-copper powder has a copper purity of 99.99% and a particle size of 10-50 nm.

[0167] (3) Surface modification treatment of the nano-copper powder:

[0168] 0.2 g of the nano-copper powder after washing is placed in 200 mL of anhydrous ethanol to obtain a nano-copper powder dispersion (dispersion B), and 150 mL of the dispersion B is added into solution A with stirring at a rate of 300 r / min, with a molar ratio of the nano-copper powder to ethyl azidoacetate being 1:3. After stirring until uniform, the stirring is continued for 0.5 h, so that the nano-copper powder and the azido functional groups of the surface modifier form a complexation reaction to form a coordination bond. After the reaction is completed, centrifugal separation is performed at a speed of 8500 r / min for 10 min, and the surface-modified nano-copper powder semi-product is obtained.

[0169] (4) Preservation of the surface-modified nano-copper powder product:

[0170] The surface-modified nanometer copper powder semi-product is washed twice with anhydrous ethanol and once with ultrapure water, and is subjected to freeze-drying treatment at -40°C for 10 h, and is stored in Ar atmosphere to obtain the surface-modified nanometer copper powder product.

[0171] Comparative Example 1

[0172] The present comparative example provides a non-modified nanometer copper powder and a preparation method thereof, which comprises the following steps:

[0173] (1) Preparation of nanometer copper powder:

[0174] 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate are dissolved in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; sodium hydroxide is dissolved in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and 35 mL of the sodium hydroxide-ethylene glycol solution is added dropwise into the above polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. The precursor solution is placed in a high-pressure reaction kettle, heated to 130°C, stirred at a speed of 500 r / min, and reacted for 3 h under a hydrogen pressure of 2 MPa to obtain an ethylene glycol solution containing nanometer copper powder. The nanometer copper powder is obtained by centrifugal separation, and the solution is washed with anhydrous ethanol for 3 times. The prepared nanometer copper powder has a copper purity of 99.99% and a particle size of 10-50 nm.

[0175] (2) The washed nanometer copper powder is washed twice with anhydrous ethanol and once with ultrapure water, and is subjected to freeze-drying treatment at -40°C for 10 h, and is stored in Ar atmosphere to obtain the non-modified nanometer copper powder.

[0176] Comparative Example 2

[0177] The present comparative example provides a non-modified nanometer copper powder and a preparation method thereof, which comprises the following steps:

[0178] (1) Preparation of nanometer copper powder:

[0179] 10 g of polyvinylpyrrolidone K30 and 0.3 g of copper sulfate pentahydrate are dissolved in 40 g of ethylene glycol to obtain a polyvinylpyrrolidone-copper salt-ethylene glycol solution; sodium hydroxide is dissolved in ethylene glycol to obtain a 0.1 mol / L sodium hydroxide-ethylene glycol solution, and 35 mL of the sodium hydroxide-ethylene glycol solution is added dropwise into the above polyvinylpyrrolidone-copper salt-ethylene glycol solution to obtain a precursor solution. The precursor solution is placed in a high-pressure reaction kettle, heated to 130°C, stirred at a speed of 500 r / min, and reacted for 3 h under a hydrogen pressure of 2 MPa to obtain an ethylene glycol solution containing nanometer copper powder. The nanometer copper powder is obtained by centrifugal separation, and the solution is washed with anhydrous ethanol for 3 times. The prepared nanometer copper powder has a copper purity of 99.99% and a particle size of 10-50 nm.

[0180] (2) The washed nano-copper powder is washed twice with anhydrous ethanol, washed once with ultrapure water, freeze-dried at -40°C for 10h, sealed with Ar, and an unmodified nano-copper powder is obtained.

[0181] Comparative Example 3

[0182] The present comparative example provides an unmodified nano-copper powder and a preparation method thereof, which comprises the following steps:

[0183] (1) Preparation of nano-copper powder:

[0184] The nano-copper powder is prepared by electrodeposition method, the current is 5A, the voltage is 20V, the duty cycle is 20%, the power-on time is 5min, the purity of the obtained nano-copper powder is 99.99%, and the size is 155-300nm.

[0185] (2) The washed nano-copper powder is washed twice with anhydrous ethanol, washed once with ultrapure water, freeze-dried at -40°C for 10h, sealed with Ar, and an unmodified nano-copper powder is obtained.

[0186] The surface modified nano-copper powder product obtained in Example 1 and the unmodified nano-copper powder of Comparative Example 1 are subjected to infrared spectrum analysis, and the results are shown in Table 1. Figure 1 As shown in Table 1, compared with the unmodified nano-copper powder, the modified surface modified nano-copper powder product has a clear peak at 3400cm -1 , indicating that the copper atoms on the surface of the copper powder have linked with ethyl azidoacetate to form stable bonds.

[0187] Figure 2 The TEM image of the surface modified nano-copper powder product of Example 1 is shown in Figure 1, which shows that the specific surface area of the copper powder is reduced due to the linking of azido functional groups on the surface of the copper powder, the agglomeration effect is reduced, no agglomerated large particles are formed, and the particle size is 10-30nm.

[0188] Figure 3 The TEM image of the surface modified nano-copper powder product of Example 2 is shown in Figure 2, which shows that the specific surface area of the copper powder is reduced due to the linking of azido functional groups on the surface of the copper powder, the agglomeration effect is reduced, no agglomerated large particles are formed, and the particle size is 10-20nm.

[0189] The surface modified nano-copper powder product obtained in Example 3, the unmodified nano-copper powder of Comparative Example 1 and azido-PEG-4 are subjected to infrared spectrum analysis, and the results are shown in Table 2. Figure 4 As shown in Table 2, compared with the unmodified nano-copper powder, the surface modified nano-copper powder product has a clear peak at 3400cm -1The obvious peak appeared, which indicated that the copper atoms on the surface of the copper powder linked with the azido-PEG-4 amine to form stable bonding. The surface-modified copper powder product after modification by the azido-PEG-4 amine had certain anti-oxidation and anti-aggregation abilities.

[0190] The unmodified copper powder of Comparative Example 1 and the surface-modified copper powder product of Example 7 were subjected to thermogravimetric analysis, and the results are shown in Figure 5 The surface-modified copper powder product of Example 7 had a smaller weight loss with the increase of temperature than the original copper powder, which indicated that the copper powder modified by the azido compound had the same anti-oxidation property.

[0191] The unmodified copper powder of Comparative Example 1 was photographed by a transmission electron microscope, and the TEM image is shown in Figure 6 It can be seen from Figure 6 that the particle size of the unmodified copper powder was 10-50 nm.

[0192] Figure 7 The TEM image of the unmodified copper powder of Comparative Example 2 can be seen that the original copper powder without surface modification was aggregated with each other, which resulted in poor dispersibility and the existence of overlapping of the particles, and thus the size of the copper powder was also large, and the copper powder particles were 41-85 nm, which was greater than 40 nm.

[0193] The unmodified copper powder of Comparative Example 3 and the surface-modified copper powder product of Example 3 were subjected to thermogravimetric analysis, and the results are shown in Figure 8 The surface-modified copper powder product had a smaller weight loss with the increase of temperature than the original copper powder, which indicated that the copper powder modified by the azido compound had the same anti-oxidation property. Therefore, the surface-modified copper powder after modification by the azido-PEG-4 amine had certain anti-oxidation and anti-aggregation abilities.

[0194] Figure 9 The TEM image of the unmodified copper powder of Comparative Example 2 can be seen that the particle size of the unmodified copper powder of Comparative Example 2 was greater than 40 nm.

[0195] Figure 10 The SEM image of the unmodified electrodeposited copper powder can be seen that the copper powder particles were aggregated with each other, especially the small particles.

[0196] Although the present application has been described in detail by the general description, specific embodiments and experiments above, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application are within the scope of the present application.

Claims

1. A surface-modified nano-copper powder, characterized in that: The invention comprises nano copper powder and a surface modifier uniformly distributed on the outer surface of the nano copper powder matrix, wherein the nano copper powder and the surface modifier are chemically bonded, and the surface modifier is an azide compound; The azide compound is a non-acidic organic compound containing an azide functional group, and the non-acidic organic compound containing an azide functional group is one of ethyl azidoacetate, azido-PEG4-amine, 3-azidopropylamine, and azido-PEG-amine.

2. A surface-modified nano copper powder according to claim 1, characterized in that, The original particle size of the nano copper powder is 5-500 nm, and the purity is greater than 99.99%.

3. A surface-modified nano copper powder according to claim 1, characterized in that, The molar ratio of the nano copper powder to the surface modifier is 1:(1-8).

4. A surface-modified nano copper powder according to claim 1, characterized in that, The particle size of the surface-modified nano-copper powder is smaller than the original particle size of the nano-copper powder, and the particle size of the surface-modified nano-copper powder is 5-200 nm.

5. The method for preparing a surface-modified nano copper powder as claimed in any one of claims 1 to 4, wherein: The following steps are involved: Adding the nano-copper powder dispersion to the surface modifier solution while stirring, stirring until the mixture is uniform and then continuing to stir to allow the nano-copper powder and the azide functional group of the surface modifier to undergo a complex reaction to form a coordination bond, and after the reaction is completed, centrifuging or filtering to obtain the solid material; The solid matter is freeze-dried and sealed to obtain a surface-modified nano-copper powder product; The surface modifier is an azide compound.

6. The method for preparing a surface-modified nano-copper powder according to claim 5, wherein: The nano copper powder dispersion is used to disperse the nano copper powder into an organic solvent, wherein the organic solvent includes anhydrous ethanol or acetone; The concentration of the surface modifier is (3-20)×10 -5 mol / L, the solute is azide compound, and the solvent is anhydrous ethanol.

7. The method for preparing a surface-modified nano-copper powder according to claim 5, wherein: The molar ratio of the nano-copper powder in the nano-copper powder dispersion to the surface modifier in the surface modifier solution is 1:(1-8).

8. The method for preparing a surface-modified nano-copper powder according to claim 5, wherein: The reaction temperature of the nano copper powder and the azide functional group of the surface modifier is room temperature, and the reaction time is 0.5 to 6 hours.

9. The use of a surface-modified nano copper powder as described in any one of claims 1 to 4, characterized in that: The surface-modified nano copper powder is used for preparing electronic interconnection slurry and lubricating grease wear-resistant additive.

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