Silver graphene conductive coating solution and preparation method thereof

Abstract

The present invention discloses a silver-graphene conductive coating solution and a preparation method thereof. The ratio of the silver-graphene conductive coating solution is: 9 to 10 mg of silver nanoparticles, 2 to 3 mg of graphene, 7 to 9 mg of polyacrylamide and 3 to 5 mg of adipic acid per 1 mL of mixed solvent; the mixed solvent is prepared by mixing N-methylpyrrolidone and xylene in a mass ratio of 2:1. First, xylene and N-methyl-2-pyrrolidone are fully mixed to obtain a mixed solvent; then, silver nanoparticles, graphene, polyacrylamide and adipic acid are added to the obtained mixed solvent and magnetically stirred, followed by stirring and dispersing using an ultrasonic crusher. After uniform dispersion, the material is discharged to obtain the product, the silver-graphene conductive coating solution. The silver-graphene conductive coating solution product prepared by the present invention has excellent conductivity and good dispersion stability.

Description

1. Technical Field:

[0001] The invention belongs to the technical field of conductive coating solutions, is mainly applicable to the field of metal wires, and specifically relates to a silver graphene conductive coating solution and a preparation method thereof. 2. Background technology:

[0002] With the rapid development of modern society and science and technology, conductive coatings, as a new functional coating, are widely used in a variety of high-end manufacturing fields, including power transmission equipment, battery energy storage, new energy equipment, and aerospace. Conductive coatings are relatively simple to use, without harsh or complex conditions. They can be used to remove static charges from substrates, conduct current, and form a coating on the substrate surface, effectively improving the substrate's electron conduction efficiency. With excellent electrical conductivity, they are considered a key development area for powder coatings and hold broad market prospects.

[0003] Silver, currently the most conductive metal, can be made into silver nanoparticles, a nanomaterial with excellent properties and widespread application in various fields. High-purity silver nanoparticles possess excellent conductivity and low resistivity. When mixed in a solution, they not only maintain their excellent conductivity but also exhibit excellent dispersion stability. They can be evenly dispersed in an appropriate carrier to form a nanosilver coating, which can form a relatively stable conductive silver film on the surface of the substrate. Graphene is a two-dimensional material composed of carbon atoms in a honeycomb structure. Its carbon atoms form bonds through sp2 hybridization, with each carbon atom forming a σ bond with three adjacent carbon atoms, and the remaining p orbital alternates to form a conjugated π bond. Graphene's large π bond allows its π electrons to move freely, giving it excellent conductivity. Its electron mobility is approximately 140 times that of silicon, making it an excellent choice for preparing conductive coating solutions.

[0004] At present, the conductive agents in conductive coating solutions on the market are mainly divided into three categories: carbon, metal and metal oxide. However, there are common problems such as unstable coating solutions, excessive content of non-conductive substances and no obvious improvement in conductivity. 3. Summary of the invention:

[0005] The technical problem addressed by the present invention is that, given the existing processes for preparing conductive coating solutions based on carbon, metal, and metal oxides, which suffer from issues such as coating solution instability, excessive levels of non-conductive substances, and limited conductivity improvement, the present invention provides a novel silver-graphene conductive coating solution and its preparation method. This solution utilizes silver nanoparticles and graphene as conductive agents in the conductive coating solution, leveraging the excellent conductivity of silver metal and the conjugated π bonds of graphene to form a stable network-like conductive system. The resulting silver-graphene conductive coating solution exhibits excellent conductivity and good dispersion stability.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] The present invention provides a silver-graphene conductive coating solution. The silver-graphene conductive coating solution has the following proportions: 9-10 mg of silver nanoparticles, 2-3 mg of graphene, 7-9 mg of a binder polyacrylamide, and 3-5 mg of adipic acid per 1 mL of a mixed solvent; the mixed solvent is prepared by mixing N-methylpyrrolidone and xylene in a mass ratio of 2:1.

[0008] According to the above-mentioned silver-graphene conductive coating solution, the average particle size of the silver nanoparticles is 7 μm.

[0009] According to the above-mentioned silver graphene conductive coating solution, the tap density of the graphene is less than 0.1 g / cm 3 , with a specific surface area of ​​530 to 580 m 2 / g, particle size <10.0 μm, pH 6.0-8.0; in the graphene, the mass fraction of carbon is ≥98%, the mass fraction of water is <1.0%, the mass fraction of chlorine is <1.0%, and the mass fraction of sulfur is <0.1%.

[0010] According to the above-mentioned silver graphene conductive coating solution, the polyacrylamide is cationic, has a molecular weight of 8 to 10 million, and an ionicity of 30 to 35%.

[0011] According to the above-mentioned silver graphene conductive coating solution, the mass fraction of the adipic acid is ≥98%.

[0012] According to the above-mentioned silver graphene conductive coating solution, the mass fraction of the xylene is ≥99%, and the concentration of water is ≤50 ppm.

[0013] According to the above-mentioned silver graphene conductive coating solution, the mass fraction of the N-methyl-2-pyrrolidone is ≥99%, the density (20° C.) is 1.025-1.029 g / mL, and the mass fraction of water is ≤0.05%.

[0014] In addition, a method for preparing a silver graphene conductive coating solution is provided, the preparation method comprising the following steps:

[0015] a. First, weigh xylene and N-methyl-2-pyrrolidone and mix them thoroughly to obtain a mixed solvent;

[0016] b. Then, the weighed silver nanoparticles, graphene, polyacrylamide and adipic acid are added to the obtained mixed solvent and magnetically stirred. After magnetic stirring, an ultrasonic crusher is used to stir and disperse the mixture. After uniform dispersion, the mixture is discharged to obtain a silver graphene conductive coating solution.

[0017] According to the above-mentioned method for preparing the silver graphene conductive coating solution, the magnetic stirring in step b is carried out at room temperature, with a rotation speed of 1500 r / min and a stirring time of 10 h.

[0018] According to the above-mentioned preparation method of the silver graphene conductive coating solution, when using an ultrasonic crusher for stirring and dispersing in step b, at room temperature, the power of the ultrasonic crusher is adjusted to 35-45%, and ultrasonic crushing is performed for 1 hour; each ultrasonication is performed for 5 minutes and then stopped for 10 minutes.

[0019] The positive beneficial effects of the present invention are:

[0020] 1. The present invention utilizes silver nanoparticles and graphene as conductive agents in a conductive coating solution. Leveraging the excellent conductivity of silver metal and the conjugated π bonds of graphene, a stable network-like conductive system is formed on the surface of the copper conductor. Consequently, the resulting product exhibits excellent conductivity and good dispersion stability.

[0021] A 5-meter silver-graphene copper composite wire coated with the silver-graphene conductive coating solution of the present invention was used for performance testing. The sample was evenly divided into five sections, each 1 meter long. The test results are detailed in Table 1.

[0022] Table 1 Comparison of electrical conductivity of copper wire before and after plating

[0023]

[0024] It can be seen from the data in Table 1 that the conductivity of the copper wire is significantly improved after being coated with the silver graphene conductive coating solution of the present invention.

[0025] 2. The technical solution of the present invention has a simple operation process, does not require harsh production conditions, and the coating solution preparation process is convenient. The surface coating of the coated copper wire is firm and can stably and significantly improve its conductivity. The conductivity is greater than 105%, which is 7% higher than that of copper wire. 4. Description of the accompanying drawings:

[0026] Figure 1 One of the scanning electron microscope (SEM) morphology images of the coating on the surface of a copper wire coated with the silver graphene conductive coating solution of the present invention;

[0027] Figure 2 The second scanning electron microscope (SEM) morphology image of the copper wire surface coated with the silver graphene conductive coating solution of the present invention;

[0028] Depend on Figure 1 and Figure 2 It can be seen that the silver graphene conductive coating solution of the present invention is stable and the coating surface is relatively smooth.

[0029] Figure 3Silver element distribution diagram of the coating of the silver graphene conductive coating solution of the present invention coated on the surface of the copper wire;

[0030] Figure 4 Carbon element distribution diagram of the coating on the surface of a copper wire coated with the silver graphene conductive coating solution of the present invention.

[0031] Depend on Figure 3 and Figure 4 It can be seen from the element scanning spectrum that the silver and carbon elements in the coating are distributed relatively evenly, without a large number of agglomeration defects; it can form a continuous and stable conductive network and improve the transmission rate of electrons. V. Specific implementation methods:

[0032] The present invention is further described below with reference to the following examples, but the scope of protection of the technical solution of the present invention is not limited thereto.

[0033] In the following examples, the average particle size of the silver nanoparticles used is 7 μm; the tap density of graphene is less than 0.1 g / cm 3 , with a specific surface area of ​​530 to 580 m 2 / g, particle size <10.0μm, pH 6.0-8.0; in the graphene, the mass fraction of carbon is ≥98%, the mass fraction of water is <1.0%, the mass fraction of chlorine is <1.0%, and the mass fraction of sulfur is <0.1%; the polyacrylamide is cationic, with a molecular weight of 8 to 10 million and an ionicity of 30 to 35%; the mass fraction of adipic acid is ≥98%; the mass fraction of xylene is ≥99%, and the concentration of water is ≤50ppm; the mass fraction of N-methyl-2-pyrrolidone is ≥99%, the density (20°C) is 1.025 to 1.029g / mL, and the mass fraction of water is ≤0.05%.

[0034] Example 1:

[0035] The silver-graphene conductive coating solution of the present invention has a ratio of: 27 mg of silver nanoparticles, 6.75 mg of graphene, 21 mg of binder polyacrylamide, and 9 mg of adipic acid are added to 3 mL of a mixed solvent; the 3 mL of mixed solvent is prepared by mixing N-methylpyrrolidone and xylene in a mass ratio of 2:1.

[0036] The prepared coating solution was poured into the filling tank, and a copper wire with a diameter of 0.2 mm was coated by a machine. The coating thickness of the silver-graphene copper composite wire was about 3 to 4 μm. The conductivity of the silver-graphene composite wire after coating is shown in Table 2.

[0037] Example 2:

[0038] The silver-graphene conductive coating solution of the present invention has a ratio of: 90 mg of silver nanoparticles, 27 mg of graphene, 81 mg of binder polyacrylamide, and 36 mg of adipic acid are added to 9 mL of a mixed solvent; the 9 mL of mixed solvent is prepared by mixing N-methylpyrrolidone and xylene in a mass ratio of 2:1.

[0039] The prepared coating solution was poured into the filling tank, and a copper wire with a diameter of 0.2 mm was coated by a machine. The coating thickness of the silver-graphene copper composite wire was about 3 to 4 μm. The conductivity of the silver-graphene composite wire after coating is shown in Table 2.

[0040] Example 3:

[0041] The silver-graphene conductive coating liquid of the present invention has the following proportions: 10 g of silver nanoparticles, 3 g of graphene, 8 g of a binder polyacrylamide, and 4 g of adipic acid are added to 1 L of a mixed solvent; the 1 L of mixed solvent is prepared by mixing N-methylpyrrolidone and xylene in a mass ratio of 2:1.

[0042] The prepared coating solution was poured into the filling tank, and a copper wire with a diameter of 0.2 mm was coated by a machine. The coating thickness of the silver-graphene copper composite wire was about 3 to 4 μm. The conductivity of the silver-graphene composite wire after coating is shown in Table 2.

[0043] The preparation method of the silver-graphene conductive coating solution described in Examples 1-3 of the present invention has the following detailed steps:

[0044] a. First, weigh xylene and N-methyl-2-pyrrolidone and mix them in proportion and fully mix to obtain a mixed solvent;

[0045] b. Then, the weighed silver nanoparticles, graphene, polyacrylamide and adipic acid are added to the obtained mixed solvent, and magnetic stirring is performed at room temperature, the magnetic stirring speed is 1500 r / min, and the stirring time is 10 hours; after magnetic stirring, stirring and dispersing are performed using an ultrasonic crusher, the power of the ultrasonic crusher is set to 40%, and ultrasonication is performed for 5 minutes, and then stopped for 10 minutes. After the ultrasonication is accumulated for 1 hour, the material is discharged to obtain the product silver graphene conductive coating solution.

[0046] The conductivity of the silver graphene conductive coating solution prepared in Examples 1-3 of the present invention was determined by the following method:

[0047] The resistance was measured using a TX-1000A intelligent metal conductor resistivity meter, and the resistivity of the sample was calculated according to the formula ρ = R*S / L. The conductivity was then calculated according to the conductivity (% IACS) = 0.017241 / ρ*100%.

[0048] Where R: resistance value of the product, Ω; ρ: resistivity, Ω·mm 2 The test results of the silver graphene conductive coating solutions prepared in Examples 1-3 of the present invention are shown in Table 2.

[0049] Table 2 Conductivity performance test results of the products prepared in Examples 1-3 of the present invention

[0050]

[0051] It can be seen from the data in Table 2 that the silver graphene conductive coating solution prepared by the technical solution of the present invention has excellent conductivity and good dispersion stability.

Claims

1. A silver graphene conductive coating solution, characterized in that The silver-graphene conductive coating solution has a ratio of 9-10 mg of silver nanoparticles, 2-3 mg of graphene, 7-9 mg of polyacrylamide (a binder), and 3-5 mg of adipic acid per 1 mL of a mixed solvent; the mixed solvent is prepared by mixing N-methylpyrrolidone and xylene in a mass ratio of 2:

1. The average particle size of the silver nanoparticles is 7 μm; the tap density of the graphene is less than 0.1 g / cm 3 , with a specific surface area of ​​530 to 580 m 2 / g, particle size <10.0 μm, pH 6.0-8.0; in the graphene, the mass fraction of carbon is ≥98%, the mass fraction of water is <1.0%, the mass fraction of chlorine is <1.0%, and the mass fraction of sulfur is <0.1%; the polyacrylamide is cationic, with a molecular weight of 8 to 10 million and an ionicity of 30 to 35%; The silver graphene conductive coating solution is used for coating copper wires; The preparation method of the silver-graphene conductive coating solution comprises the following steps: a. First, weigh xylene and N-methyl-2-pyrrolidone and mix them thoroughly to obtain a mixed solvent; b. Then, the weighed silver nanoparticles, graphene, polyacrylamide and adipic acid are added to the obtained mixed solvent and magnetically stirred. After magnetic stirring, an ultrasonic crusher is used to stir and disperse the mixture. After uniform dispersion, the mixture is discharged to obtain a silver graphene conductive coating solution.

2. The silver graphene conductive coating solution according to claim 1, characterized in that: The mass fraction of the adipic acid is ≥98%.

3. The silver graphene conductive coating solution according to claim 1, characterized in that: The mass fraction of the xylene is ≥99%, and the concentration of water is ≤50ppm.

4. The silver graphene conductive coating solution according to claim 1, characterized in that: The mass fraction of the N-methyl-2-pyrrolidone is ≥99%, the density (20° C.) is 1.025-1.029 g / mL, and the mass fraction of water is ≤0.05%.

5. The silver graphene conductive coating solution according to claim 1, characterized in that: The magnetic stirring in step b is carried out at room temperature, with a rotation speed of 1500 r / min and a stirring time of 10 h.

6. The silver graphene conductive coating solution according to claim 1, characterized in that: When stirring and dispersing with an ultrasonic crusher in step b, the power of the ultrasonic crusher is adjusted to 35-45% at room temperature, and ultrasonic crushing is performed for 1 hour; ultrasonication is performed for 5 minutes and then stopped for 10 minutes.

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