Low-temperature conductive silver paste and preparation method thereof
By combining silver nanosheet reinforcements with silver nanoparticles and modifying their surfaces, a low-temperature conductive silver paste was prepared, solving the problem of silver particle bonding at low temperatures and achieving high conductivity and stability, making it suitable for flexible electronic applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DONGGUAN JIAYU ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2025-10-21
- Publication Date
- 2026-05-12
AI Technical Summary
Existing low-temperature conductive silver pastes have difficulty achieving effective connections between silver particles at low temperatures, which limits their application on flexible substrates.
A composite conductive filler was formed by combining silver nanosheets and silver nanoparticles through evaporation self-assembly technology, and then surface-modified with 3,4-dimethoxyphenylethylamine. The low-temperature conductive silver paste was prepared by combining acrylic resin, solvent and additives.
Effective connections between silver particles were achieved at low temperatures, improving conductivity and adhesion, and enhancing the uniformity and stability of the conductive network, making it suitable for flexible electronics applications.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of conductive silver paste technology, specifically to a low-temperature conductive silver paste and its preparation method. Background Technology
[0002] Low-temperature conductive silver paste arose from the urgent need in electronics manufacturing for both low-temperature processes and flexible substrates, and its development can be traced back to the rise of flexible electronics technology in the late 20th century. Traditional high-temperature conductive silver pastes have curing temperatures exceeding 600°C, relying on high-temperature sintering to achieve metallurgical bonding between silver particles. However, this process places extremely high demands on the temperature resistance of the substrate, limiting its application on flexible substrates such as plastics, paper, and fabrics. With the rise of emerging fields such as wearable devices, foldable screen phones, and printed electronics, the market urgently needs a conductive material that can cure at low temperatures or even room temperature to be compatible with heat-sensitive substrates and reduce energy consumption. The research and development of low-temperature conductive silver paste thus began, with its core breakthrough lying in achieving effective bonding between silver particles at low temperatures through chemical modification or physical regulation.
[0003] Low-temperature conductive silver paste is mainly composed of silver powder, resin matrix, solvent, and additives. Among them, silver powder, as the conductive core, exists in the form of tiny particles. By optimizing its morphology, size, and dispersion process, dispersion is effectively promoted to form a uniform conductive network. By rationally selecting the resin matrix, controlling the volatility of the solvent, and adding appropriate additives, high-efficiency conductivity at low temperatures is achieved, thereby meeting the needs of low-temperature processing conductive materials in fields such as flexible electronics. Summary of the Invention
[0004] The purpose of this invention is to provide a low-temperature conductive silver paste and its preparation method to solve the problems existing in the prior art.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-temperature conductive silver paste, comprising the following components: acrylic resin, composite conductive filler, solvent and additives; the composite conductive filler is prepared by compounding silver nanosheet reinforcement with silver nanoparticles with a particle size of 15-20 nm and then surface-modifying with 3,4-dimethoxyphenylethylamine; the silver nanosheet reinforcement is mainly composed of silver nanosheets with a diameter of 300-600 nm and a thickness of 10-40 nm, and is formed by overlapping and interlacing single-walled carbon nanotubes with a diameter of 1-5 nm and a length of 20-50 μm on its surface and in the gaps through evaporation self-assembly technology.
[0006] Furthermore, the solvent is one or a combination of two of ethyl acetate and cyclohexanone.
[0007] Furthermore, the additive is one or more combinations of KH560, polyvinylpyrrolidone, and sodium dodecyl sulfonate.
[0008] Furthermore, a method for preparing a low-temperature conductive silver paste includes the following preparation steps:
[0009] (1) At room temperature, pretreated carbon nanotubes and accelerators were mixed in deionized water and ultrasonically stirred for 20 min to obtain carbon nanotube dispersion; silver nanosheets were added to carbon nanotube dispersion and stirred at room temperature for 10 min, then heated to 55-65℃ for evaporation self-assembly for 55-65 min, and the evaporation self-assembly was repeated several times to obtain silver nanosheet reinforcement.
[0010] (2) At room temperature, silver nanosheet reinforcement and silver nanoparticles were mixed in anhydrous methanol, and 3,4-dimethoxyphenylethylamine was added under stirring. The reaction was carried out for 2-3 hours, and the composite conductive filler was obtained after filtration, washing and drying.
[0011] (3) Mix the acrylic resin and solvent evenly, then add the composite conductive filler and additives, stir at 20-30℃ for 30-40 minutes to obtain low-temperature conductive silver paste.
[0012] Furthermore, the carbon nanotubes pretreated in step (1) are obtained by treatment with a mixed acid solution.
[0013] Furthermore, in step (1), the mass ratio of pretreated carbon nanotubes, promoter, deionized water, and silver nanosheets is 1:1:100:5-7.
[0014] Furthermore, the number of repetitions in step (1) is 3-5 times.
[0015] Furthermore, the promoter in step (1) is one or both of bacterial cellulose and sodium alginate.
[0016] Furthermore, in step (2), the mass ratio of silver nanosheet reinforcement, silver nanoparticles, anhydrous methanol, and 3,4-dimethoxyphenylethylamine is 5:1.8-2.4:30:3-5.
[0017] Furthermore, in step (3), the mass ratio of acrylic resin, solvent, additives and composite conductive filler is 10-12:20-26:1-2:60-70.
[0018] Compared with the prior art, the beneficial effects achieved by the present invention are:
[0019] This invention prepares low-temperature conductive silver paste using acrylic resin, composite conductive filler, solvent, and additives as raw materials. The conductive silver paste with acrylic resin as a carrier has low sheet resistance and can be cured into a film at low temperature, exhibiting good conductivity and adhesion. The composite conductive filler is formed by combining silver nanosheet reinforcement and silver nanoparticles. The combination of small-diameter silver nanoparticles helps to improve the density of the composite conductive filler and increase contact performance. The resulting conductive silver paste has high conductivity and stability.
[0020] The silver nanosheet reinforcement is formed by overlapping and interlacing one-dimensional carbon nanotubes on the surface and in the gaps of two-dimensional silver nanosheets through evaporation self-assembly technology. The carbon nanotubes have higher electrical conductivity and can fill the gaps between the silver nanosheets, ensuring high-speed electron transport. The bridges built between the silver nanosheets help improve the transmission efficiency of the three-dimensional conductive network, thereby improving the conductivity of the silver paste. Subsequently, the silver nanosheet reinforcement is compounded with silver nanoparticles to form a composite conductive filler. The composite conductive filler is surface modified with 3,4-dimethoxyphenylethylamine. The amino groups on the 3,4-dimethoxyphenylethylamine molecule can be adsorbed on the surface of the composite conductive filler through coordination. The presence of benzene rings and methoxy groups increases the steric hindrance between the fillers, overcoming the disadvantage of easy agglomeration, thereby effectively improving the dispersion stability. At the same time, the enhanced uniformity of the conductive network further enhances the conductivity of the conductive silver paste. Detailed Implementation
[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0022] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The testing methods for various indicators of a low-temperature conductive silver paste prepared in the following embodiments are as follows:
[0023] Volume resistivity test: The low-temperature conductive silver paste of the present invention was printed on a glass plate until the thickness was 5 μm. It was then surface dried for 120 min at 23°C and 50% relative humidity to obtain a low-temperature conductive silver film. The low-temperature conductive silver film was prepared into a circular sample with a diameter of 12 mm. Its resistance was tested using a resistance meter, and then the volume resistivity of the conductive silver paste was calculated.
[0024] Stability performance: The low-temperature conductive silver paste of the present invention was left to stand at room temperature for 1 day, 3 days and 5 days. The stability performance of the low-temperature conductive silver paste was evaluated by calculating the sedimentation percentage. Sedimentation percentage (%) = (volume of supernatant liquid × 100) / (volume of total silver paste). The higher the sedimentation percentage, the more stable the silver paste.
[0025] KH560 is a silane coupling agent, and SC8008 is an acrylic resin.
[0026] Example 1
[0027] (1) By mass fraction, at room temperature, 1 part of single-walled carbon nanotubes with a diameter of 1 nm and a length of 20 μm were added to 50 parts of mixed acid solution. The mixed acid solution was prepared by mixing 95 wt% concentrated sulfuric acid aqueous solution and 65 wt% concentrated nitric acid aqueous solution in a volume ratio of 3:1. After stirring and mixing at 50 rpm for 20 min, the mixture was ultrasonically stirred at 50 °C for 2 h with an ultrasonic power of 200 W. Then, it was poured into 500 parts of deionized water and centrifuged at 8000 rpm for 20 min. The precipitate was taken and diluted and centrifuged multiple times in the same way until the pH of the supernatant was 7. Then, it was filtered, the lower precipitate was taken, and dried at 70 °C for 14 h to obtain pretreated carbon nanotubes.
[0028] (2) By mass fraction, at room temperature, 1 part of pretreated carbon nanotubes and 1 part of bacterial cellulose with a diameter of 50 nm and a length of 20 μm were mixed in 100 parts of deionized water and ultrasonically stirred for 20 min with an ultrasonic power of 300 W to obtain a carbon nanotube dispersion.
[0029] (3) By mass fraction, at room temperature, 5 parts of silver nanosheets with a diameter of 300 nm and a thickness of 15 nm were added to the carbon nanotube dispersion and stirred at 150 rpm for 10 min. Then, the temperature was raised to 55 °C for evaporation and self-assembly for 55 min. After the self-assembly was completed, the solid was filtered and the second self-assembly was performed. The filtered solid was placed in 100 parts of carbon nanotube dispersion. The self-assembly parameters were the same as above. After repeating the self-assembly a total of 3 times, the silver nanosheet reinforcement was obtained.
[0030] (4) By mass fraction, at room temperature, 5 parts of silver nanosheet reinforcement and 1.8 parts of silver nanoparticles with a particle size of 10 nm were mixed in 30 parts of anhydrous methanol. 3 parts of 3,4-dimethoxyphenylethylamine were added while stirring at 500 rpm. The reaction was carried out for 2 h. The solid was filtered and washed 3 times with deionized water. The solid was dried at 60 °C for 8 h to obtain the composite conductive filler.
[0031] (5) By mass, 10 parts of acrylic resin of model SC8008 and 20 parts of ethyl acetate are mixed and stirred at 100 rpm for 15 min at 20°C. Then, 1 part of KH560 and 69 parts of composite conductive filler are added and stirred at 200 rpm for 30 min to obtain low-temperature conductive silver paste.
[0032] Example 2
[0033] (1) By mass fraction, 1 part of single-walled carbon nanotubes with a diameter of 2 nm and a length of 25 μm were added to 50 parts of mixed acid solution. The mixed acid solution was prepared by mixing 95 wt% concentrated sulfuric acid aqueous solution and 65 wt% concentrated nitric acid aqueous solution in a volume ratio of 3:1. After stirring and mixing at 50 rpm for 20 min, the mixture was ultrasonically stirred at 50 °C for 2 h with an ultrasonic power of 200 W. Then, it was poured into 500 parts of deionized water and centrifuged at 8000 rpm for 20 min. The precipitate was taken and diluted and centrifuged multiple times in the same way until the pH of the supernatant was 7. Then, it was filtered, the lower precipitate was taken, and dried at 70 °C for 14 h to obtain pretreated carbon nanotubes.
[0034] (2) By mass fraction, at room temperature, 1 part of pretreated carbon nanotubes, 0.3 parts of sodium alginate aqueous solution with a concentration of 3 mg / mL, and 0.7 parts of bacterial cellulose with a diameter of 50 nm and a length of 20 μm were mixed in 100 parts of deionized water and ultrasonically stirred for 20 min with an ultrasonic power of 300 W to obtain a carbon nanotube dispersion.
[0035] (3) By mass fraction, at room temperature, 5.5 parts of silver nanosheets with a diameter of 400 nm and a thickness of 20 nm were added to 100 parts of carbon nanotube dispersion and stirred at 150 rpm for 10 min. Then, the temperature was raised to 57 °C for evaporation and self-assembly for 55 min. After the self-assembly was completed, the solid was filtered and the second self-assembly was performed. The filtered solid was placed in 100 parts of carbon nanotube dispersion. The self-assembly parameters were the same as above. After repeating the self-assembly a total of 3 times, the silver nanosheet reinforcement was obtained.
[0036] (4) By mass fraction, at room temperature, 5 parts of silver nanosheet reinforcement and 1.9 parts of silver nanoparticles with a particle size of 10 nm were mixed in 30 parts of anhydrous methanol, and 3.5 parts of 3,4-dimethoxyphenylethylamine were added under stirring speed of 500 rpm. The reaction was carried out for 2 h, the solid was filtered and washed 3 times with deionized water, and dried at 60 °C for 8 h to obtain composite conductive filler;
[0037] (5) By mass, 10.5 parts of acrylic resin of model SC8008, 11 parts of ethyl acetate and 11 parts of cyclohexanone are mixed and stirred at 100 rpm for 15 min at 23°C. Then, 0.3 parts of sodium dodecyl sulfonate, 1 part of KH560 and 66.2 parts of composite conductive filler are added and stirred at 200 rpm for 30 min to obtain low temperature conductive silver paste.
[0038] Example 3
[0039] (1) By mass fraction, 1 part of single-walled carbon nanotubes with a diameter of 3 nm and a length of 35 μm were added to 50 parts of mixed acid solution. The mixed acid solution was prepared by mixing 95 wt% concentrated sulfuric acid aqueous solution and 65 wt% concentrated nitric acid aqueous solution in a volume ratio of 3:1. After stirring and mixing at 50 rpm for 20 min, the mixture was ultrasonically stirred at 50 °C for 2 h with an ultrasonic power of 200 W. Then, it was poured into 500 parts of deionized water and centrifuged at 8000 rpm for 20 min. The precipitate was taken and diluted and centrifuged multiple times in the same way until the pH of the supernatant was 7. Then, it was filtered, the lower precipitate was taken, and dried at 70 °C for 14 h to obtain pretreated carbon nanotubes.
[0040] (2) By mass fraction, at room temperature, 1 part of pretreated carbon nanotubes, 0.3 parts of sodium alginate aqueous solution with a concentration of 3 mg / mL, and 0.7 parts of bacterial cellulose with a diameter of 50 nm and a length of 20 μm were mixed in 100 parts of deionized water and ultrasonically stirred for 20 min with an ultrasonic power of 300 W to obtain a carbon nanotube dispersion.
[0041] (3) By mass fraction, at room temperature, 6 parts of silver nanosheets with a diameter of 450 nm and a thickness of 25 nm were added to 100 parts of carbon nanotube dispersion and stirred at 150 rpm for 10 min. Then, the temperature was raised to 60 °C for evaporation and self-assembly for 60 min. After the self-assembly was completed, the solid was filtered and the second self-assembly was performed. The filtered solid was placed in 100 parts of carbon nanotube dispersion. The self-assembly parameters were the same as above. After repeating the self-assembly a total of 4 times, the silver nanosheet reinforcement was obtained.
[0042] (4) By mass fraction, at room temperature, 5 parts of silver nanosheet reinforcement and 2.1 parts of silver nanoparticles with a particle size of 15 nm were mixed in 30 parts of anhydrous methanol, and 4 parts of 3,4-dimethoxyphenylethylamine were added under stirring speed of 500 rpm. The reaction was carried out for 2.5 h, the solid was filtered and washed 3 times with deionized water, and dried at 60 °C for 8 h to obtain the composite conductive filler.
[0043] (5) By mass, 11 parts of acrylic resin of model SC8008, 11.5 parts of ethyl acetate and 11.5 parts of cyclohexanone are mixed and stirred at 100 rpm for 15 min at 25°C. Then, 0.4 parts of polyvinylpyrrolidone, 1.1 parts of KH560 and 64.5 parts of composite conductive filler are added and stirred at 200 rpm for 35 min to obtain low-temperature conductive silver paste.
[0044] Example 4
[0045] (1) By mass fraction, 1 part of single-walled carbon nanotubes with a diameter of 4 nm and a length of 40 μm were added to 50 parts of mixed acid solution. The mixed acid solution was prepared by mixing 95 wt% concentrated sulfuric acid aqueous solution and 65 wt% concentrated nitric acid aqueous solution in a volume ratio of 3:1. After stirring and mixing at 50 rpm for 20 min, the mixture was ultrasonically stirred at 50 °C for 2 h with an ultrasonic power of 200 W. Then, it was poured into 500 parts of deionized water and centrifuged at 8000 rpm for 20 min. The precipitate was taken and diluted and centrifuged multiple times in the same way until the pH of the supernatant was 7. Then, it was filtered, the lower precipitate was taken, and dried at 70 °C for 14 h to obtain pretreated carbon nanotubes.
[0046] (2) By mass fraction, at room temperature, 1 part of pretreated carbon nanotubes and 1 part of bacterial cellulose with a diameter of 50 nm and a length of 20 μm were mixed in 100 parts of deionized water and ultrasonically stirred for 20 min with an ultrasonic power of 300 W to obtain a carbon nanotube dispersion.
[0047] (3) By mass fraction, at room temperature, 6.5 parts of silver nanosheets with a diameter of 500 nm and a thickness of 30 nm were added to the carbon nanotube dispersion and stirred at 150 rpm for 10 min. Then, the temperature was raised to 62 °C for evaporation and self-assembly for 60 min. After the self-assembly was completed, the solid was filtered and the second self-assembly was performed. The filtered solid was placed in 100 parts of carbon nanotube dispersion. The self-assembly parameters were the same as above. After repeating the self-assembly for a total of 4 times, the silver nanosheet reinforcement was obtained.
[0048] (4) By mass fraction, at room temperature, 5 parts of silver nanosheet reinforcement and 2.2 parts of silver nanoparticles with a particle size of 15 nm were mixed in 30 parts of anhydrous methanol, and 4.5 parts of 3,4-dimethoxyphenylethylamine were added under stirring speed of 500 rpm. The reaction was carried out for 2.5 h, the solid was filtered and washed 3 times with deionized water, and dried at 60 °C for 8 h to obtain the composite conductive filler.
[0049] (5) By mass, 11.5 parts of acrylic resin of model SC8008 and 24.5 parts of cyclohexanone are mixed and stirred at 100 rpm for 15 min at 27°C. Then, 0.4 parts of sodium dodecyl sulfonate, 1.3 parts of KH560 and 62.3 parts of composite conductive filler are added and stirred at 200 rpm for 35 min to obtain low-temperature conductive silver paste.
[0050] Example 5
[0051] (1) By mass fraction, 1 part of single-walled carbon nanotubes with a diameter of 5 nm and a length of 50 μm were added to 50 parts of mixed acid solution. The mixed acid solution was prepared by mixing 95 wt% concentrated sulfuric acid aqueous solution and 65 wt% concentrated nitric acid aqueous solution in a volume ratio of 3:1. After stirring and mixing at 50 rpm for 20 min, the mixture was ultrasonically stirred at 50 °C for 2 h with an ultrasonic power of 200 W. Then, it was poured into 500 parts of deionized water and centrifuged at 8000 rpm for 20 min. The precipitate was taken and diluted and centrifuged multiple times in the same way until the pH of the supernatant was 7. Then, it was filtered, the lower precipitate was taken, and dried at 70 °C for 14 h to obtain pretreated carbon nanotubes.
[0052] (2) By mass fraction, at room temperature, 1 part of pretreated carbon nanotubes, 0.3 parts of sodium alginate aqueous solution with a concentration of 3 mg / mL, and 0.7 parts of bacterial cellulose with a diameter of 50 nm and a length of 20 μm were mixed in 100 parts of deionized water and ultrasonically stirred for 20 min with an ultrasonic power of 300 W to obtain a carbon nanotube dispersion.
[0053] (3) By mass fraction, at room temperature, 7 parts of silver nanosheets with a diameter of 600 nm and a thickness of 40 nm were added to 100 parts of carbon nanotube dispersion and stirred at 150 rpm for 10 min. Then, the temperature was raised to 65 °C for evaporation and self-assembly for 65 min. After the self-assembly was completed, the solid was filtered and the second self-assembly was performed. The filtered solid was placed in 100 parts of carbon nanotube dispersion. The self-assembly parameters were the same as above. After repeating the self-assembly a total of 5 times, the silver nanosheet reinforcement was obtained.
[0054] (4) By mass fraction, at room temperature, 5 parts of silver nanosheet reinforcement and 2.4 parts of silver nanoparticles with a particle size of 20 nm were mixed in 30 parts of anhydrous methanol. 5 parts of 3,4-dimethoxyphenylethylamine were added while stirring at 500 rpm. The reaction was carried out for 3 h. The solid was filtered and washed 3 times with deionized water. The solid was dried at 60 °C for 8 h to obtain the composite conductive filler.
[0055] (5) By mass, 12 parts of acrylic resin of model SC8008, 13 parts of ethyl acetate and 13 parts of cyclohexanone are mixed and stirred at 100 rpm for 15 min at 30°C. Then, 0.5 parts of polyvinylpyrrolidone, 1.5 parts of KH560 and 60 parts of composite conductive filler are added and stirred at 200 rpm for 40 min to obtain low-temperature conductive silver paste.
[0056] Comparative Example 1
[0057] The difference between Comparative Example 1 and Example 3 is that step (1) is omitted, and step (2) is changed to: by mass parts, at room temperature, 1 part of carbon nanotubes, 0.3 parts of sodium alginate aqueous solution with a concentration of 3 mg / mL, and 0.7 parts of bacterial cellulose with a diameter of 50 nm and a length of 20 μm are mixed in 100 parts of deionized water, and ultrasonically stirred for 20 min at an ultrasonic power of 300 W to obtain a carbon nanotube dispersion; the remaining steps are the same as in Example 3.
[0058] Comparative Example 2
[0059] The difference between Comparative Example 2 and Example 3 is that step (3) is different. Step (3) is changed to: by mass, at room temperature, 6 parts of silver nanosheets with a diameter of 450 nm and a thickness of 25 nm are added to 100 parts of carbon nanotube dispersion and stirred at 150 rpm for 10 min to obtain silver nanosheet-carbon nanotube composite material; Step (4) is changed to: by mass, at room temperature, 5 parts of silver nanosheet-carbon nanotube composite material and 2.1 parts of silver nanoparticles with a particle size of 15 nm are mixed in 30 parts of anhydrous methanol, and 4 parts of 3,4-dimethoxyphenylethylamine are added at a stirring speed of 500 rpm. The reaction is carried out for 2.5 h, the solid is filtered, washed 3 times with deionized water, and dried at 60 °C for 8 h to obtain composite conductive filler; the remaining steps are the same as in Example 3.
[0060] Comparative Example 3
[0061] The difference between Comparative Example 3 and Example 3 is that step (4) is different. Step (4) is changed to: by mass parts, at room temperature, 5 parts of silver nanosheet reinforcement and 2.1 parts of silver nanoparticles with a particle size of 15 nm are mixed in 30 parts of anhydrous methanol, stirred at a stirring speed of 500 rpm for 2.5 h, filtered to obtain solid, washed 3 times with deionized water, and dried at 60 °C for 8 h to obtain composite conductive filler; the remaining steps are the same as in Example 3.
[0062] Example of effect
[0063] Table 1 below shows the performance analysis results of a low-temperature conductive silver paste using Examples 1 to 5 and Comparative Examples 1 to 3 of the present invention.
[0064] Table 1
[0065]
[0066] A comparison of the experimental data on volume resistivity of the embodiments and comparative examples reveals that the present invention first uses two-dimensional silver nanosheets as the main body, and then uses evaporation self-assembly technology to allow one-dimensional carbon nanotubes to overlap and interweave on the surface and in the gaps to form a silver nanosheet reinforcement. The higher conductivity of the carbon nanotubes ensures high-speed electron transport, acts as a bridge between the silver nanosheets, and effectively improves the transmission efficiency of the three-dimensional conductive network. The combination of conductive materials of different sizes and shapes can improve the density of the composite conductive filler, increase contact performance, and achieve the effect of improving the conductivity of the silver paste. Furthermore, the benzene ring and methyl ring on the 3,4-dimethoxyphenethylamine molecule... The presence of oxygen groups increases the steric hindrance between the composite conductive fillers, overcoming their tendency to agglomerate, thereby effectively improving the dispersion performance and enhancing the uniformity of the conductive network, which in turn further enhances the conductivity of the conductive silver paste. A comparison of the stability experimental data from the examples and comparative examples reveals that this invention utilizes the coordination of the amino groups on the 3,4-dimethoxyphenethylamine molecule to adsorb onto the surface of the composite conductive filler, successfully modifying the filler surface. The presence of benzene rings and methoxy groups increases the steric hindrance between the fillers, effectively improving the dispersion stability of the fillers and reducing the possibility of stratification.
[0067] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.
Claims
1. A method for preparing a low-temperature conductive silver paste, characterized in that, The preparation steps include the following: (1) At room temperature, pretreated carbon nanotubes and accelerators were mixed in deionized water and ultrasonically stirred for 20 min to obtain carbon nanotube dispersion; silver nanosheets were added to carbon nanotube dispersion and stirred at room temperature for 10 min, then heated to 55-65℃ for evaporation self-assembly for 55-65 min, and the evaporation self-assembly was repeated several times to obtain silver nanosheet reinforcement. (2) At room temperature, silver nanosheet reinforcement and silver nanoparticles were mixed in anhydrous methanol, and 3,4-dimethoxyphenylethylamine was added under stirring. The reaction was carried out for 2-3 hours, and the composite conductive filler was obtained after filtration, washing and drying. (3) Mix the acrylic resin and solvent evenly, then add the composite conductive filler and additives, stir at 20-30℃ for 30-40 min to obtain low-temperature conductive silver paste; The carbon nanotubes in step (1) are pretreated using a mixed acid solution. In step (1), the mass ratio of pretreated carbon nanotubes, accelerator, deionized water, and silver nanosheets is 1:1:100:5-7. The number of repetitions in step (1) is 3-5 times; The accelerator in step (1) is one or two of bacterial cellulose and sodium alginate; In step (2), the mass ratio of silver nanosheet reinforcement, silver nanoparticles, anhydrous methanol, and 3,4-dimethoxyphenylethylamine is 5:1.8-2.4:30:3-5. In step (3), the mass ratio of acrylic resin, solvent, additives and composite conductive filler is 10-12:20-26:1-2:60-70.