A highly dispersible conductive silver powder paste composition and its preparation method

Abstract

This invention relates to the field of conductive paste technology, and more particularly to a highly dispersible conductive silver powder paste composition and its preparation method. The aforementioned highly dispersible conductive silver powder paste composition is characterized by comprising, by weight, the following components: 10-20 parts of aqueous epoxy resin, 1-5 parts of aqueous acrylic resin, 10-20 parts of bisphenol A epoxy resin, 1-5 parts of activated graphene, 50-70 parts of flake silver powder, 5-15 parts of dopamine hydrochloride, 1-2 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 1-2 parts of dispersant, 1-2 parts of curing agent, and 0.1-0.5 parts of curing accelerator. This invention utilizes the high thermal conductivity of graphene to effectively disperse localized heat, and its chemical inertness delays the oxidation of silver powder at high temperatures. The epoxy resin and acrylic resin composite system forms a thermally stable cross-linked structure, resulting in reduced microcracks after curing, a coefficient of thermal expansion matching the substrate, and reduced interfacial stress caused by thermal shock.

Description

Technical Field

[0001] This invention relates to the field of conductive paste technology, and in particular to a highly dispersible conductive silver powder paste composition and its preparation method. Background Technology

[0002] Conductive paste, as a basic electronic material with specific functions, is widely used in electronic circuit fields such as printed circuit boards, solar cells, surface mount technology, RFID radio frequency antennas, touch screen circuits, and flexible printed circuits (FPCs). Currently, conductive silver paste is one of the key raw materials in electronic circuit production, which determines the final application performance of conductive silver paste.

[0003] Conductive silver paste is a core material in electronic circuit manufacturing, and its performance directly affects the reliability of products such as printed circuit boards, solar cells, and flexible electronics. While current technology has achieved basic functional applications, insufficient storage stability remains a concern. Silver paste is prone to sedimentation and stratification during long-term storage, leading to uneven distribution of conductive particles. Traditional dispersion systems cannot effectively suppress silver powder agglomeration, and the paste viscosity fluctuates significantly over time, affecting printing accuracy and batch consistency.

[0004] Existing conductive agents (such as graphene and carbon nanotubes) require high addition amounts to form a conductive network, but excessive addition can damage the rheological properties of the paste, resulting in high contact resistance between silver particles and large surface roughness of the cured conductive film, leading to increased signal transmission loss. Simultaneously, the interfacial adhesion between the silver paste and the substrate is insufficient, making it prone to peeling, especially under bending or thermal shock conditions. Some resin systems exhibit poor compatibility with silver powder, forming microcracks after curing, further reducing mechanical strength.

[0005] With the rapid innovation and development of the electronic information industry, the conductive silver paste industry is also developing at a rapid pace. Various industries have increasingly higher requirements for the performance of pastes, and have put forward extremely detailed requirements for the performance of conductive silver paste. How to improve the storage stability of silver paste, improve the interfacial bonding force after curing, and enhance the thermal stability have become technical problems that need to be solved. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a highly dispersible conductive silver powder paste composition and its preparation method.

[0007] A highly dispersible conductive silver powder paste composition, wherein the raw materials, by weight, include: 10-20 parts of waterborne epoxy resin, 1-5 parts of waterborne acrylic resin, 10-20 parts of bisphenol A epoxy resin, 1-5 parts of activated graphene, 50-70 parts of flake silver powder, 5-15 parts of dopamine hydrochloride, 1-2 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 1-2 parts of dispersant, 1-2 parts of curing agent, and 0.1-0.5 parts of curing accelerator.

[0008] Preferably, the waterborne epoxy resin has an epoxy equivalent of 700-750 g / eq and a solid content of 40-60%.

[0009] Preferably, the solid content of the waterborne acrylic resin is 55-65%.

[0010] Preferably, the curing agent is a polyamide-based curing agent.

[0011] Preferably, the curing accelerator is an amine-based curing accelerator.

[0012] More preferably, the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0013] Preferably, the activated graphene is prepared by the following steps: dispersing spherical silver powder and dispersant in water, adding graphene oxide while stirring, stirring for 1-3 hours, adding hydroiodic acid and ultrasonically treating for 1-4 hours, filtering, washing, and vacuum drying.

[0014] More preferably, the mass ratio of spherical silver powder, dispersant, graphene oxide, and hydroiodic acid is 5-10:1-2:1-3:1-2.

[0015] More preferably, the ultrasonic frequency is 70-90kHz and the ultrasonic temperature is 50-70℃.

[0016] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0017] S1. Stir the water-based epoxy resin and water-based acrylic resin evenly, add activated graphene and stir for 10-30 minutes to obtain the preform.

[0018] S2. Add the flake silver powder to Tris-HCl buffer solution with pH 8-9 and stir evenly. Add dopamine hydrochloride and sonicate for 1-3 hours. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 10-30 minutes. Add bisphenol A epoxy resin and stir at 70-90℃ for 1-2 hours. Filter, wash and vacuum dry to obtain composite silver powder.

[0019] S3. Add composite silver powder and dispersant to the preform and stir for 1-2 hours. Degas under vacuum, then add curing agent, curing accelerator and deionized water. Stir under vacuum until uniform.

[0020] Beneficial effects:

[0021] This invention employs a combination of activated graphene and composite silver powder. The graphene coating layer formed after the reduction of graphene oxide can effectively inhibit the sedimentation of silver powder. Its sheet structure reduces the migration of silver powder particles caused by gravity through van der Waals forces and hydrogen bonding. Meanwhile, the surface of the sheet-like silver powder modified with dopamine hydrochloride forms polar functional groups, which generate intermolecular forces with the aqueous resin system, further inhibiting delamination.

[0022] The oriented network of activated graphene and the sheet-like structure of composite silver powder form complementary conductive pathways. The high conductivity of graphene provides a fast electron transport channel, while the dopamine hydrochloride-epoxy resin interface layer of silver powder reduces contact resistance through a cross-linking reaction. During the curing process, the two permeate each other to form a dense conductive network, reducing energy loss in the signal transmission path.

[0023] This invention utilizes the chemical bonding between water-based resin and dopamine hydrochloride to modify silver powder, which significantly enhances the interfacial bonding force. The cross-linked network formed after curing significantly enhances the adhesion between the silver paste and the substrate. In particular, the flexibility of the resin can buffer stress and prevent peeling when bent.

[0024] This invention also utilizes the high thermal conductivity of graphene to effectively disperse local heat, its chemical inertness to delay the oxidation of silver powder at high temperatures, and the composite system of epoxy resin and acrylic resin to form a thermally stable cross-linked structure. After curing, microcracks are reduced, the coefficient of thermal expansion matches the substrate, and the interfacial stress caused by thermal shock is reduced. Attached Figure Description

[0025] Figure 1 The viscosity changes of the conductive silver powder paste compositions obtained in Example 5 and Comparative Examples 1-2 during 60 days at room temperature are shown in the graph.

[0026] Figure 2 The graph shows the sheet resistance change of the silver film obtained by placing the conductive silver powder paste compositions obtained in Example 5 and Comparative Examples 1-2 at room temperature for 60 days.

[0027] Figure 3 The graph shows a comparison of the tensile strength and high-temperature resistance days of silver films prepared using the conductive silver powder paste compositions obtained in Example 5 and Comparative Examples 1-2. Detailed Implementation

[0028] The present invention will be further explained below with reference to specific embodiments.

[0029] The Huntsman Araldite PZ3961-1 used below is a water-based epoxy resin sourced from Huntsman Corporation, USA. The water-based acrylic resin used below was purchased from Shanghai Shuaike Chemical Co., Ltd., model SK6535A. The epoxy resin E51 used below was sourced from Baling Petrochemical, China. The spherical silver powder used below was purchased from Jiangsu Jinzixuan Metal Technology Co., Ltd. The flake silver powder used below was purchased from Lingshou County Bohan Mineral Products Co., Ltd. The DVK-Disper 41000 used below was purchased from Chengdu Huidigao Chemical Products Co., Ltd. The polyamide curing agent 650 used below was purchased from Jinan Jibin Chemical Co., Ltd. The BYK-110 used below was sourced from BYK Chemical, Germany.

[0030] Example 1

[0031] A highly dispersible conductive silver powder paste composition, comprising the following raw materials: Huntsman Araldite PZ3961-1 10g, aqueous acrylic resin 1g, epoxy resin E51 10g, activated graphene 1g, flake silver powder 50g, dopamine hydrochloride 5g, γ-glycidyl etheroxypropyltrimethoxysilane 1g, DVK-Disper 41000 1g, polyamide curing agent 650 1g, and 2,4,6-tris(dimethylaminomethyl)phenol 0.1g.

[0032] Activated graphene was prepared by the following steps: 5g of spherical silver powder and 1g of BYK-110 were dispersed in 30g of water, and 1g of graphene oxide was added while stirring. The mixture was stirred at 1000r / min for 1h, 1g of hydroiodic acid was added, and the mixture was ultrasonically treated for 1h at a frequency of 70kHz and a temperature of 50℃. The mixture was then filtered, washed, and vacuum dried.

[0033] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0034] S1. Add Huntsman Araldite PZ3961-1 and water-based acrylic resin to a mixer and stir until homogeneous. Add activated graphene and stir at 100 r / min for 10 min to obtain the preform.

[0035] S2. Add the flake silver powder to 150g of Tris-HCl buffer solution with a pH of 8-9 and stir until homogeneous. Add dopamine hydrochloride and sonicate for 1h at a frequency of 70kHz. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 10min. Add epoxy resin E51 and stir at 70℃ for 1h at a stirring speed of 100r / min. Filter, wash, and vacuum dry to obtain composite silver powder.

[0036] S3. Add composite silver powder and DVK-Disper 41000 to the preform and stir for 1 hour, then vacuum degas. Add polyamide curing agent 650, 2,4,6-tris(dimethylaminomethyl)phenol and 5g of deionized water and stir evenly under vacuum.

[0037] Example 2

[0038] A highly dispersible conductive silver powder paste composition, comprising the following raw materials: Huntsman Araldite PZ3961-1 20g, waterborne acrylic resin 5g, epoxy resin E51 20g, activated graphene 5g, flake silver powder 70g, dopamine hydrochloride 15g, γ-glycidyl etheroxypropyltrimethoxysilane 2g, DVK-Disper 41000 2g, polyamide curing agent 650 2g, and 2,4,6-tris(dimethylaminomethyl)phenol 0.5g.

[0039] Activated graphene was prepared by the following steps: 10g of spherical silver powder and 2g of BYK-110 were dispersed in 60g of water, and 3g of graphene oxide was added while stirring. The mixture was stirred at 2000r / min for 3h, and 2g of hydroiodic acid was added. The mixture was then sonicated for 4h at a frequency of 90kHz and a temperature of 70℃. The mixture was then filtered, washed, and vacuum dried.

[0040] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0041] S1. Add Huntsman Araldite PZ3961-1 and water-based acrylic resin to a mixer and stir until homogeneous. Add activated graphene and stir at 500 r / min for 30 min to obtain the preform.

[0042] S2. Add the flake silver powder to 300g of Tris-HCl buffer solution with pH 8-9 and stir until homogeneous. Add dopamine hydrochloride and sonicate for 3h at a frequency of 90kHz. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 30min. Add epoxy resin E51 and stir at 90℃ for 2h at a stirring speed of 400r / min. Filter, wash, and vacuum dry to obtain composite silver powder.

[0043] S3. Add composite silver powder and DVK-Disper 41000 to the preform and stir for 2 hours, then vacuum degas. Add polyamide curing agent 650, 2,4,6-tris(dimethylaminomethyl)phenol and 12g of deionized water and stir evenly under vacuum.

[0044] Example 3

[0045] A highly dispersible conductive silver powder paste composition, comprising the following raw materials: Huntsman Araldite PZ3961-1 12g, waterborne acrylic resin 4g, epoxy resin E51 12g, activated graphene 4g, flake silver powder 55g, dopamine hydrochloride 12g, γ-glycidyl etheroxypropyltrimethoxysilane 1.2g, DVK-Disper 41000 1.8g, polyamide curing agent 650 1.3g, and 2,4,6-tris(dimethylaminomethyl)phenol 0.4g.

[0046] Activated graphene was prepared by the following steps: 7g of spherical silver powder and 1.7g of BYK-110 were dispersed in 40g of water, and 2.5g of graphene oxide was added while stirring. The mixture was stirred at 1200r / min for 2.5h, and 1.3g of hydroiodic acid was added. The mixture was then sonicated for 3h at a frequency of 75kHz and a temperature of 65℃. The mixture was then filtered, washed, and vacuum dried.

[0047] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0048] S1. Add Huntsman Araldite PZ3961-1 and water-based acrylic resin to a mixer and stir until homogeneous. Add activated graphene and stir at 200 r / min for 25 min to obtain the preform.

[0049] S2. Add the flake silver powder to 200g of Tris-HCl buffer solution with a pH of 8-9 and stir until homogeneous. Add dopamine hydrochloride and sonicate for 2.5h at a frequency of 75kHz. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 25min. Add epoxy resin E51 and stir at 75℃ for 100min at a stirring speed of 200r / min. Filter, wash, and vacuum dry to obtain composite silver powder.

[0050] S3. Add composite silver powder and DVK-Disper 41000 to the preform and stir for 100 minutes, then vacuum degas. Add polyamide curing agent 650, 2,4,6-tris(dimethylaminomethyl)phenol and 6g of deionized water and stir evenly under vacuum.

[0051] Example 4

[0052] A highly dispersible conductive silver powder paste composition, comprising the following raw materials: Huntsman Araldite PZ3961-1 18g, waterborne acrylic resin 2g, epoxy resin E51 18g, activated graphene 2g, flake silver powder 65g, dopamine hydrochloride 8g, γ-glycidyl etheroxypropyltrimethoxysilane 1.8g, DVK-Disper 41000 1.2g, polyamide curing agent 650 1.7g, and 2,4,6-tris(dimethylaminomethyl)phenol 0.2g.

[0053] Activated graphene was prepared by the following steps: 9g of spherical silver powder and 1.3g of BYK-110 were dispersed in 50g of water, and 1.5g of graphene oxide was added while stirring. The mixture was stirred at 1800r / min for 1.5h, and 1.7g of hydroiodic acid was added. The mixture was then sonicated for 2h at a frequency of 85kHz and a temperature of 55℃. The mixture was then filtered, washed, and vacuum dried.

[0054] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0055] S1. Add Huntsman Araldite PZ3961-1 and water-based acrylic resin to a mixer and stir until homogeneous. Add activated graphene and stir at 400 r / min for 15 min to obtain the preform.

[0056] S2. Add the flake silver powder to 240g of Tris-HCl buffer solution with a pH of 8-9 and stir until homogeneous. Add dopamine hydrochloride and sonicate for 1.5h at a frequency of 85kHz. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 15min. Add epoxy resin E51 and stir at 85℃ for 80min at a stirring speed of 300r / min. Filter, wash, and vacuum dry to obtain composite silver powder.

[0057] S3. Add composite silver powder and DVK-Disper 41000 to the preform and stir for 80 minutes, then vacuum degas. Add polyamide curing agent 650, 2,4,6-tris(dimethylaminomethyl)phenol and 10g deionized water and stir evenly under vacuum.

[0058] Example 5

[0059] A highly dispersible conductive silver powder paste composition, comprising the following raw materials: Huntsman Araldite PZ3961-1 15g, waterborne acrylic resin 3g, epoxy resin E51 15g, activated graphene 3g, flake silver powder 60g, dopamine hydrochloride 10g, γ-glycidyl etheroxypropyltrimethoxysilane 1.5g, DVK-Disper 41000 1.5g, polyamide curing agent 650 1.5g, and 2,4,6-tris(dimethylaminomethyl)phenol 0.3g.

[0060] Activated graphene was prepared by the following steps: 8g of spherical silver powder and 1.5g of BYK-110 were dispersed in 45g of water, and 2g of graphene oxide was added while stirring. The mixture was stirred at 1500r / min for 2h, and 1.5g of hydroiodic acid was added. The mixture was then sonicated for 2.5h at a frequency of 80kHz and a temperature of 60℃. The mixture was then filtered, washed, and vacuum dried.

[0061] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0062] S1. Add Huntsman Araldite PZ3961-1 and water-based acrylic resin to a mixer and stir until homogeneous. Add activated graphene and stir at 300 r / min for 30 min to obtain the preform.

[0063] S2. Add the flake silver powder to 220g of Tris-HCl buffer solution with a pH of 8-9 and stir until homogeneous. Add dopamine hydrochloride and sonicate for 2h at a frequency of 80kHz. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 20min. Add epoxy resin E51 and stir at 80℃ for 90min at a stirring speed of 250r / min. Filter, wash, and vacuum dry to obtain composite silver powder.

[0064] S3. Add composite silver powder and DVK-Disper 41000 to the preform and stir for 90 minutes, then vacuum degas. Add polyamide curing agent 650, 2,4,6-tris(dimethylaminomethyl)phenol and 8g of deionized water and stir evenly under vacuum.

[0065] Comparative Example 1

[0066] A highly dispersible conductive silver powder paste composition, comprising the following raw materials: Huntsman Araldite PZ3961-1 15g, waterborne acrylic resin 3g, epoxy resin E51 15g, activated graphene 3g, flake silver powder 60g, dopamine hydrochloride 10g, γ-glycidyl etheroxypropyltrimethoxysilane 1.5g, DVK-Disper 41000 1.5g, polyamide curing agent 650 1.5g, and 2,4,6-tris(dimethylaminomethyl)phenol 0.3g.

[0067] Activated graphene was prepared by the following steps: 1.5g BYK-110 was dispersed in 45g water, and 2g graphene oxide was added while stirring. The mixture was stirred at 1500r / min for 2h, 1.5g hydroiodic acid was added, and the mixture was ultrasonically treated for 2.5h at a frequency of 80kHz and a temperature of 60℃. The mixture was then filtered, washed, and vacuum dried. 8g spherical silver powder was added and mixed evenly.

[0068] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0069] S1. Add Huntsman Araldite PZ3961-1 and water-based acrylic resin to a mixer and stir until homogeneous. Add activated graphene and stir at 300 r / min for 30 min to obtain the preform.

[0070] S2. Add the flake silver powder to 220g of Tris-HCl buffer solution with a pH of 8-9 and stir until homogeneous. Add dopamine hydrochloride and sonicate for 2h at a frequency of 80kHz. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 20min. Add epoxy resin E51 and stir at 80℃ for 90min at a stirring speed of 250r / min. Filter, wash, and vacuum dry to obtain composite silver powder.

[0071] S3. Add composite silver powder and DVK-Disper 41000 to the preform and stir for 90 minutes, then vacuum degas. Add polyamide curing agent 650, 2,4,6-tris(dimethylaminomethyl)phenol and 8g of deionized water and stir evenly under vacuum.

[0072] Comparative Example 2

[0073] A highly dispersible conductive silver powder paste composition, comprising the following raw materials: Huntsman Araldite PZ3961-1 30g, aqueous acrylic resin 3g, activated graphene 3g, flake silver powder 60g, dopamine hydrochloride 10g, γ-glycidyl etheroxypropyltrimethoxysilane 1.5g, DVK-Disper 41000 1.5g, polyamide curing agent 650 1.5g, and 2,4,6-tris(dimethylaminomethyl)phenol 0.3g.

[0074] Activated graphene was prepared by the following steps: 8g of spherical silver powder and 1.5g of BYK-110 were dispersed in 45g of water, and 2g of graphene oxide was added while stirring. The mixture was stirred at 1500r / min for 2h, and 1.5g of hydroiodic acid was added. The mixture was then sonicated for 2.5h at a frequency of 80kHz and a temperature of 60℃. The mixture was then filtered, washed, and vacuum dried.

[0075] The preparation method of the above-mentioned highly dispersed conductive silver powder paste composition includes the following steps:

[0076] S1. Add Huntsman Araldite PZ3961-1 and water-based acrylic resin to a mixer and stir until homogeneous. Add activated graphene and stir at 300 r / min for 30 min to obtain the preform.

[0077] S2. Add the flake silver powder to 220g of Tris-HCl buffer with pH 8-9 and stir well. Add dopamine hydrochloride and sonicate for 2h at a frequency of 80kHz. Add γ-glycidoxypropyltrimethoxysilane and continue sonicating for 20min. Filter, wash and vacuum dry to obtain composite silver powder.

[0078] S3. Add composite silver powder and DVK-Disper 41000 to the preform and stir for 90 minutes, then vacuum degas. Add polyamide curing agent 650, 2,4,6-tris(dimethylaminomethyl)phenol and 8g of deionized water and stir evenly under vacuum.

[0079] The conductive silver powder paste compositions obtained in Example 5 and Comparative Examples 1-2 were placed at room temperature for 60 days (the day of placement is day 0). Samples were taken on day 0, day 1, day 14, day 28 and day 60 to measure the viscosity of each group (average value of 10 rpm test for 2 min). On the day of sampling, the silver film was coated on the surface of a flat glass using screen printing technology with a film thickness of 25±5 μm. The sheet resistance of each group of silver films was tested using a four-probe tester.

[0080] like Figure 1 and Figure 2As shown, the conductive silver powder paste composition obtained in Example 5 showed no significant change in viscosity and sheet resistance during room temperature storage, while the conductive silver powder paste compositions obtained in Comparative Examples 1-2 showed a rapid increase in viscosity and sheet resistance during room temperature storage. This confirms that the conductive silver powder paste composition obtained in this invention has long-term storage stability, can effectively inhibit silver powder agglomeration, and the paste viscosity does not fluctuate easily over time, effectively ensuring printing accuracy and batch consistency.

[0081] The conductive silver powder paste compositions obtained in Example 5 and Comparative Examples 1-2 were coated onto the surface of flat glass using screen printing technology, with a film thickness of 25±5μm. The tensile strength of the silver film was tested using a welding method well-known to those skilled in the art (standard silver-plated copper sheet welding). The number of days that the resistivity and adhesion of each group of silver films did not decrease when placed in an environment with a temperature of 50°C and a humidity of 90% RH was also measured.

[0082] like Figure 3 As shown, the silver film prepared using the conductive silver powder paste composition obtained in Example 5 has the highest tensile strength and high temperature resistance days, which are superior to Comparative Examples 1-2 (P<0.05).

[0083] The reason for the above results is that this invention uses activated graphene and composite silver powder to form a three-dimensional spatial network structure. The graphene coating layer formed after the reduction of graphene oxide can effectively inhibit the sedimentation of spherical silver powder. Its sheet structure fixes the spherical silver powder through van der Waals forces and hydrogen bonds, reducing particle migration caused by gravity. Meanwhile, the surface of the sheet-like silver powder modified with dopamine hydrochloride forms polar functional groups, generating intermolecular forces with the aqueous resin system, further inhibiting delamination. The oriented network of activated graphene and the sheet-like structure of composite silver powder form complementary conductive pathways. The high conductivity of graphene provides a fast electron transport channel, while the dopamine hydrochloride-epoxy resin interface layer of silver powder reduces contact resistance through cross-linking reaction. During the curing process, the two permeate each other to form a dense conductive network, reducing energy loss in the signal transmission path. This invention utilizes the chemical bonding between aqueous resin and dopamine hydrochloride-modified silver powder to significantly improve interfacial bonding. The cross-linked network formed after curing significantly enhances the adhesion between the silver paste and the substrate. In particular, the flexibility of the resin can buffer stress and prevent peeling when bent.

[0084] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A highly dispersible conductive silver powder paste composition, characterized in that, The raw materials, by weight, include: 10-20 parts of waterborne epoxy resin, 1-5 parts of waterborne acrylic resin, 10-20 parts of bisphenol A epoxy resin, 1-5 parts of activated graphene, 50-70 parts of flake silver powder, 5-15 parts of dopamine hydrochloride, 1-2 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 1-2 parts of dispersant, 1-2 parts of curing agent, and 0.1-0.5 parts of curing accelerator. The following steps are used to prepare it: S1. Stir the water-based epoxy resin and water-based acrylic resin evenly, add activated graphene and stir for 10-30 minutes to obtain the preform. S2. Add the flake silver powder to Tris-HCl buffer solution with pH 8-9 and stir evenly. Add dopamine hydrochloride and sonicate for 1-3 hours. Add γ-glycidoxypropyltrimethoxysilane and continue sonication for 10-30 minutes. Add bisphenol A epoxy resin and stir at 70-90℃ for 1-2 hours. Filter, wash and vacuum dry to obtain composite silver powder. S3. Add composite silver powder and dispersant to the preform and stir for 1-2 hours. Degas under vacuum, add curing agent, curing accelerator and deionized water, and stir under vacuum until uniform. The activated graphene is prepared by the following steps: spherical silver powder and dispersant are dispersed in water, graphene oxide is added under stirring, stirred for 1-3 hours, hydroiodic acid is added and ultrasonically treated for 1-4 hours, filtered, washed, and vacuum dried. The mass ratio of spherical silver powder, dispersant, graphene oxide, and hydroiodic acid is 5-10:1-2:1-3:1-2.

2. The highly dispersible conductive silver powder paste composition according to claim 1, characterized in that, The epoxy equivalent of waterborne epoxy resin is 700-750 g / eq, and the solid content is 40-60%.

3. The highly dispersible conductive silver powder paste composition according to claim 1, characterized in that, The solid content of waterborne acrylic resin is 55-65%.

4. The highly dispersible conductive silver powder paste composition according to claim 1, characterized in that, The curing agent is a polyamide-based curing agent.

5. The highly dispersible conductive silver powder paste composition according to claim 1, characterized in that, The curing accelerator is an amine-based curing accelerator.

6. The highly dispersible conductive silver powder paste composition according to claim 1, characterized in that, The curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

7. The highly dispersible conductive silver powder paste composition according to claim 1, characterized in that, In the preparation of activated graphene, the ultrasonic frequency is 70-90kHz and the ultrasonic temperature is 50-70℃.

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