A nano-silver powder filler enhanced conductive paste composition and a preparation method thereof

Abstract

The application relates to the technical field of conductive paste, and discloses a nano-silver powder filler reinforced conductive paste composition and a preparation method thereof, which comprises the following raw materials in parts by mass: nano-silver powder 50-70 parts, composite silver nanowires 10-20 parts, solvent 110-150 parts, binder 80-100 parts, curing agent 5-10 parts and accelerator 1-2 parts. The composite silver nanowires can reduce the overall resistance and improve the conductive performance, the porous nano-zinc oxide contained in the composite silver nanowires is coated on the surface of the silver nanowires, can block the contact of oxygen / moisture molecules with the silver nanowires, and the carboxyl-polyethylene glycol-carboxyl long-chain molecular structure on the surface of the composite silver nanowires can block the sedimentation of the modified silver nanowires, improve the dispersion stability of the modified silver nanowires in the conductive paste, and enhance the conductive performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of conductive paste, in particular to a kind of nano silver powder filler enhanced conductive paste composition and preparation method thereof. BACKGROUND

[0002] Conductive paste is a kind of mixed paste composed of high-purity silver particles, binder, solvent and additives, which can be cured into a film on the surface of a substrate (such as plastic, ceramic, glass or flexible film), forming a highly conductive and strongly adhered conductive coating, and is widely used in chip bonding, flexible electronics, radar, solar cells and flexible electronic terminals.

[0003] As an electronic material, conductive paste is increasingly widely used in the field of electrical conduction. To improve the conductivity of existing conductive paste, nano silver powder and silver nanowires are added. However, nano silver particles and silver nanowires are prone to agglomeration, affecting the interface between raw materials. Meanwhile, conductive paste uses resin raw materials, which may cause poor interface between organic and inorganic raw materials, resulting in sedimentation of conductive paste and affecting the conductivity of conductive paste, thereby limiting the use efficiency of conductive paste composition.

[0004] Based on the above statement, the present application provides a kind of nano silver powder filler enhanced conductive paste composition and preparation method thereof. SUMMARY

[0005] The present application provides a kind of nano silver powder filler enhanced conductive paste composition and preparation method thereof, which solves the problem of poor interface between organic and inorganic raw materials in conductive paste.

[0006] Technical scheme of the present application:

[0007] A kind of nano silver powder filler enhanced conductive paste composition, comprising the following mass parts of raw materials:

[0008] Nano silver powder 50-70 parts, composite silver nanowire 10-20 parts, solvent 110-150 parts, binder 80-100 parts, curing agent 5-10 parts, and promoter 1-2 parts;

[0009] The composite silver nanowire is coated on the surface of modified silver nanowire by carboxyl-polyethylene glycol-carboxyl and hydroxypropyl methyl cellulose.

[0010] The modified silver nanowire is obtained by depositing porous nano zinc oxide on the surface of silver nanowire modified by polydopamine, and then modifying the surface with amino silane and mixing with aniline and graphene oxide.

[0011] A kind of nano silver powder filler enhanced conductive paste composition and preparation method thereof, comprising the following preparation steps:

[0012] Composite silver nanowires, silver nanopowder, solvent, and binder are mixed and stirred at 500-600 r / min for 5-10 min to obtain a mixture. A curing agent and an accelerator are added to the mixture and stirred at 500-600 r / min for 15-20 min to obtain a conductive paste composition.

[0013] Furthermore, the solvent is selected from any one of butyl acetate, ethanol, and n-butanol;

[0014] Furthermore, the adhesive is bisphenol A epoxy resin with an epoxy equivalent of 180-200.

[0015] Furthermore, the curing agent is selected from any one of hexamethylphthalic anhydride, dicarboxylic anhydride, and maleic anhydride;

[0016] Furthermore, the accelerator is selected from any one of 2-methylimidazole, 1-benzyl-2-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole.

[0017] Furthermore, the composite silver nanowires are specifically prepared by the following steps:

[0018] A1. Add silver nanowires to Tris-HCl buffer solution, stir until homogeneous, add dopamine, stir to react, filter, wash and dry to obtain polydopamine-modified silver nanowires.

[0019] A2. Add polydopamine-modified silver nanowires and porous zinc oxide nanowires to deionized water, stir, filter, wash, and dry to obtain silver nanowires coated with porous zinc oxide nanowires.

[0020] A3. Add the porous zinc oxide-coated silver nanowires to ethanol and deionized water, stir until homogeneous, add γ-aminopropyltriethoxysilane, stir until the reaction is complete, cool to room temperature, filter, wash and dry to obtain aminated porous zinc oxide-coated silver nanowires.

[0021] A4. Add aniline, graphene oxide and acetic acid solution to deionized water, stir evenly, add ammonium persulfate and silver nanowires coated with aminated porous zinc oxide nanowires, stir to react, filter, wash and dry to obtain modified silver nanowires.

[0022] A5. Add hydroxypropyl methylcellulose to deionized water and stir until homogeneous. Add modified silver nanowires and stir. Add carboxyl-polyethylene glycol-carboxyl groups and stir at 60-70℃ for 20-30 minutes. After filtration, washing, and drying, composite silver nanowires are obtained.

[0023] Furthermore, during the A1 reaction described above, in the Tris-HCl buffer solution, dopamine can self-polymerize on the surface of silver nanowires to form polydopamine, thus forming polydopamine-modified silver nanowires. This allows the silver nanowires to carry a large number of phenolic hydroxyl groups, which is beneficial for adhering porous zinc oxide nanowires to the surface of the silver nanowires.

[0024] Furthermore, during the A2 reaction process described above, the polydopamine-modified silver nanowires exhibit excellent adhesion and contain a large number of phenolic hydroxyl groups, which enable them to adhere porous zinc oxide nanowires to the surface of the polydopamine-modified silver nanowires. This allows the porous zinc oxide nanowires to be uniformly deposited on the surface of the polydopamine-modified silver nanowires, resulting in silver nanowires coated with porous zinc oxide nanowires.

[0025] Furthermore, during the A3 reaction process described above, the silanol groups generated by the hydrolysis of aminosilane can chemically bond with the hydroxyl groups on the surface of the silver nanowires coated with porous zinc oxide, thereby grafting aminosilane onto the surface of the silver nanowires coated with porous zinc oxide to obtain aminated porous zinc oxide-coated silver nanowires.

[0026] Furthermore, in the A4 reaction process described above, using graphene oxide as a template, under the action of ammonium persulfate as an initiator, the aniline monomer reacts with the amino groups on the surface of the silver nanowires coated with aminated porous zinc oxide nanowires, forming branched and trunk-shaped polyaniline on the graphene oxide nanosheets. As polymerization continues, the branched and trunk-shaped structures cause the graphene oxide nanosheets to curl along the aminated porous zinc oxide nanowires coated with silver nanowires, forming a tubular structure with the aminated porous zinc oxide nanowires coated with silver nanowires as the core material and graphene-polyaniline as the shell, thus obtaining modified silver nanowires.

[0027] Furthermore, during the A5 reaction described above, hydroxypropyl methylcellulose exhibits excellent adhesion properties, adhering to the surface of the modified silver nanowires and imparting oxygen-containing functional groups to the modified silver nanowires. This is beneficial for the dispersion of the modified silver nanowires in the conductive paste. Moreover, the carboxyl groups contained in the carboxyl-polyethylene glycol-carboxyl group can be chemically bonded to the oxygen-containing functional groups of hydroxypropyl methylcellulose, allowing the carboxyl-polyethylene glycol-carboxyl group to be grafted onto the modified silver nanowires, resulting in composite silver nanowires.

[0028] Further, in step A1, the ratio of silver nanowires, Tris-HCl buffer, and dopamine is (1.2-1.7) g: (60-80) mL: (0.4-0.6) g.

[0029] Furthermore, in step A2, the ratio of polydopamine-modified silver nanowires, porous zinc oxide nanoparticles, and deionized water is (1-1.4) g:(0.2-0.4) g:(75-85) mL.

[0030] Further, in step A3, the ratio of the amount of porous zinc oxide-coated silver nanowires, ethanol, deionized water and γ-aminopropyltriethoxysilane is (1.2-1.4)g:(40-50)mL:(10-20)mL:(0.5-1)g.

[0031] Further, in step A4, the ratio of aniline, graphene oxide, acetic acid solution, deionized water, ammonium persulfate, and silver nanowires coated with aminated porous zinc oxide is (1.5-2.5)g:(2.5-3.5)g:(1-3)mL:(80-100)mL:(0.1-0.3)g:(1-1.4)g.

[0032] Further, in step A5, the ratio of hydroxypropyl methylcellulose, deionized water, modified silver nanowires and carboxyl-polyethylene glycol-carboxyl is (0.5-0.9)g:(45-55)mL:(1.3-1.7)g:(0.7-0.9)g.

[0033] Furthermore, the silver nanowires have a length of 10-20 μm and a diameter of 60-100 nm.

[0034] Furthermore, the graphene oxide sheets have a diameter of 0.5-1 μm and a thickness of 2.4-3.6 nm.

[0035] The present invention has the following beneficial effects:

[0036] (1) In the technical solution of the present invention, polydopamine is formed by self-polymerization on the surface of silver nanowires, forming polydopamine-modified silver nanowires, which have excellent adhesion and contain a large number of phenolic hydroxyl groups, which is beneficial to the adhesion of porous nano zinc oxide on the surface of silver nanowires and improves conductivity. Porous nano zinc oxide is uniformly deposited on the surface of polydopamine-modified silver nanowires. On the one hand, porous nano zinc oxide has a high specific surface area and porosity, providing more surface active sites and excellent conductivity. Combined with silver nanowires, it improves the conductivity of the conductive paste composition. On the other hand, porous nano zinc oxide coated on the surface of silver nanowires can block oxygen / water molecules from contacting the silver nanowires, avoiding the formation of oxides by silver nanowires with oxygen, which would reduce the conductivity of the silver paste composition. Moreover, as a carrier of porous nano zinc oxide, silver nanowires can improve the dispersibility of porous nano zinc oxide in the conductive paste composition and improve conductivity.

[0037] (2) In the technical solution of the present invention, graphene oxide nanosheets are used as templates. Silver nanowires coated with aminated porous zinc oxide and aniline monomers are polymerized on the graphene oxide nanosheets, which causes the graphene oxide nanosheets to curl along the aminated porous zinc oxide coated silver nanowires to form a tubular structure with the aminated porous zinc oxide coated silver nanowires as the core and graphene-polyaniline as the shell. On the one hand, the porous zinc oxide coated silver nanowires fill the carbon nanotube structure formed by graphene-polyaniline, forming an interconnected conductive path with the porous zinc oxide and silver nanowires, which allows electrons to be transported along the pore walls, reducing the overall resistance and improving the conductivity. In addition, the graphene oxide nanosheets and polyaniline have high conductivity, which enhances the conductivity. On the other hand, the graphene oxide nanosheets and polyaniline-derived carbon nanotubes coat the surface of the porous zinc oxide coated silver nanowires, further blocking oxygen and water molecules from contacting the silver nanowires and improving the conductivity.

[0038] (3) In the technical solution of the present invention, hydroxypropyl methylcellulose is adhered to the surface of modified silver nanowires, giving the modified silver nanowires excellent oxygen-containing functional groups, which is beneficial to the dispersibility of modified silver nanowires in conductive paste. Furthermore, the carboxyl-polyethylene glycol-carboxyl grafted onto the modified silver nanowires, with the long-chain molecular structure of carboxyl-polyethylene glycol-carboxyl, can prevent the sedimentation of modified silver nanowires and improve the stability of conductive paste. In addition, the modified silver nanowires modified with carboxyl-polyethylene glycol-carboxyl can be uniformly dispersed in conductive paste, improving the dispersion stability of modified silver nanowires in conductive paste and enhancing conductivity. Detailed Implementation

[0039] 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.

[0040] The raw materials used in the embodiments of this invention are shown below, and all reagents used are analytical grade.

[0041] The solvent is butyl acetate, the binder is selected from bisphenol A epoxy resin with an epoxy equivalent of 190, the curing agent is hexamethylphthalic anhydride, and the accelerator is 2-methylimidazole.

[0042] The silver nanowires are 15 μm long and 80 nm in diameter.

[0043] The graphene oxide sheet has a diameter of 0.6 μm and a thickness of 3 nm.

[0044] The nano-silver powder has a particle size of 50nm.

[0045] Porous nano zinc oxide is prepared by the following steps:

[0046] Zinc acetate was dissolved in methanol to prepare a zinc acetate methanol solution with a zinc ion concentration of 0.02 mol / L; potassium hydroxide was dissolved in methanol to prepare a potassium hydroxide methanol solution with a hydroxide ion concentration of 0.7 mol / L; the potassium hydroxide methanol solution was slowly added dropwise to the zinc acetate methanol solution stirred at 70℃, while maintaining a zinc ion to hydroxide ion molar ratio of 1:6. The mixture was stirred and evaporated at 50℃ until the volume of the reaction solution was concentrated to 30% of its original volume. The reaction vessel was then sealed and the reaction was continued at 50℃ for 3 hours. After the reaction was complete, the mixture was cooled and washed twice by centrifugation with methanol, and then dried in an oven at 80℃ to obtain porous nano zinc oxide.

[0047] The porous zinc oxide nanoparticles have a particle size of 30 nm and a pore size of 6 nm.

[0048] Example 1

[0049] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0050] 50 parts of nano silver powder, 10 parts of composite silver nanowires, 110 parts of butyl acetate, 80 parts of bisphenol A epoxy resin, 5 parts of hexamethylphthalic anhydride, and 1 part of 2-methylimidazole.

[0051] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0052] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 500 r / min for 5 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 500 r / min for 15 min to obtain a conductive paste composition.

[0053] The composite silver nanowires are prepared by the following steps:

[0054] A1. Add 1.2g of silver nanowires to 60mL of Tris-HCl buffer solution with pH 8.5, stir well, add 0.4g of dopamine, stir and react at 30℃ for 4h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain polydopamine modified silver nanowires.

[0055] A2. Add 1g of polydopamine-modified silver nanowires and 0.2g of porous zinc oxide nanowires to 75mL of deionized water, stir at 200r / min for 40min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain silver nanowires coated with porous zinc oxide nanowires.

[0056] A3. 1.2 g of porous zinc oxide-coated silver nanowires were added to 40 mL of ethanol and 10 mL of deionized water and stirred until homogeneous. 0.5 g of γ-aminopropyltriethoxysilane was added and stirred at 70 °C for 2 h. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70 °C for 10 min to obtain aminated porous zinc oxide-coated silver nanowires.

[0057] A4. Add 1.5g aniline, 2.5g graphene oxide and 1mL of 10% acetic acid solution to 80mL of deionized water, stir well, add 0.1g ammonium persulfate and 1g aminated porous zinc oxide-coated silver nanowires, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0058] A5. Add 0.5g of hydroxypropyl methylcellulose to 55mL of deionized water and stir well. Add 1.3g of modified silver nanowires and stir for 30min. Add 0.7g of carboxyl-polyethylene glycol-carboxyl and stir at 60℃ for 20min. After filtration, wash three times with deionized water and dry in an oven at 70℃ for 15min to obtain composite silver nanowires.

[0059] Example 2

[0060] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0061] 60 parts of nano silver powder, 15 parts of composite silver nanowires, 130 parts of butyl acetate, 90 parts of bisphenol A epoxy resin, 8 parts of hexamethylphthalic anhydride, and 1.5 parts of 2-methylimidazole;

[0062] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0063] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 550 r / min for 8 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 550 r / min for 18 min to obtain a conductive paste composition.

[0064] The composite silver nanowires are prepared by the following steps:

[0065] A1. Add 1.5g of silver nanowires to 70mL of Tris-HCl buffer solution with pH 8.5, stir well, add 0.5g of dopamine, stir and react at 30℃ for 4h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain polydopamine modified silver nanowires.

[0066] A2. Add 1.2g of polydopamine-modified silver nanowires and 0.3g of porous zinc oxide nanowires to 80mL of deionized water, stir at 200r / min for 40min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain silver nanowires coated with porous zinc oxide nanowires.

[0067] A3. 1.3 g of porous zinc oxide-coated silver nanowires were added to 45 mL of ethanol and 15 mL of deionized water and stirred until homogeneous. 0.7 g of γ-aminopropyltriethoxysilane was added and stirred at 70 °C for 2 h. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70 °C for 10 min to obtain aminated porous zinc oxide-coated silver nanowires.

[0068] A4. Add 2g aniline, 3g graphene oxide and 2mL of 10% acetic acid solution to 90mL of deionized water, stir well, add 0.2g ammonium persulfate and 1.2g ammonium oxide-coated silver nanowires, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0069] A5. Add 0.7g of hydroxypropyl methylcellulose to 50mL of deionized water and stir well. Add 1.5g of modified silver nanowires and stir for 30min. Add 0.8g of carboxyl-polyethylene glycol-carboxyl and stir at 65℃ for 25min. After filtration, wash three times with deionized water and dry in an oven at 70℃ for 15min to obtain composite silver nanowires.

[0070] Example 3

[0071] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0072] 70 parts of nano silver powder, 20 parts of composite silver nanowires, 150 parts of butyl acetate, 100 parts of bisphenol A epoxy resin, 10 parts of hexamethylphthalic anhydride, and 2 parts of 2-methylimidazole.

[0073] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0074] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 600 r / min for 10 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 600 r / min for 20 min to obtain a conductive paste composition.

[0075] The composite silver nanowires are prepared by the following steps:

[0076] A1. 1.7 g of silver nanowires were added to 80 mL of Tris-HCl buffer solution with pH 8.5 and stirred until homogeneous. 0.6 g of dopamine was added and the mixture was stirred at 30 °C for 4 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70 °C for 10 min to obtain polydopamine-modified silver nanowires.

[0077] A2. Add 1.4g of polydopamine-modified silver nanowires and 0.4g of porous zinc oxide nanowires to 85mL of deionized water, stir at 200r / min for 40min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain silver nanowires coated with porous zinc oxide nanowires.

[0078] A3. 1.4 g of porous zinc oxide-coated silver nanowires were added to 50 mL of ethanol and 20 mL of deionized water and stirred until homogeneous. 1 g of γ-aminopropyltriethoxysilane was added and the mixture was stirred at 70 °C for 2 h. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70 °C for 10 min to obtain aminated porous zinc oxide-coated silver nanowires.

[0079] A4. Add 2.5g aniline, 3.5g graphene oxide and 3mL of 10% acetic acid solution to 100mL deionized water, stir well, add 0.3g ammonium persulfate and 1.4g aminated porous zinc oxide-coated silver nanowires, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0080] A5. Add 0.9g of hydroxypropyl methylcellulose to 55mL of deionized water and stir until homogeneous. Add 1.7g of modified silver nanowires and stir for 30min. Add 0.9g of carboxyl-polyethylene glycol-carboxyl and stir at 70℃ for 30min. After filtration, wash three times with deionized water and dry in a 70℃ oven for 15min to obtain composite silver nanowires.

[0081] Comparative Example 1

[0082] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0083] 70 parts of nano silver powder, 20 parts of composite silver nanowires, 150 parts of butyl acetate, 100 parts of bisphenol A epoxy resin, 10 parts of hexamethylphthalic anhydride, and 2 parts of 2-methylimidazole.

[0084] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0085] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 600 r / min for 10 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 600 r / min for 20 min to obtain a conductive paste composition.

[0086] The composite silver nanowires are prepared by the following steps:

[0087] A1. Add 1.4g of silver nanowires and 0.4g of porous nano zinc oxide to 85mL of deionized water, stir at 200r / min for 40min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain a mixture;

[0088] A2. Add 1.4g of the mixture to 50mL of ethanol and 20mL of deionized water, stir well, add 1g of γ-aminopropyltriethoxysilane, stir and react at 70℃ for 2h, cool to room temperature, filter, wash 3 times with ethanol and 3 times with deionized water, dry in an oven at 70℃ for 10min to obtain the aminated mixture.

[0089] A3. Add 2.5g aniline, 3.5g graphene oxide and 3mL of 10% acetic acid solution to 100mL deionized water, stir well, add 0.3g ammonium persulfate and 1.4g ammonium oxide mixture, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0090] A4. Add 0.9g of hydroxypropyl methylcellulose to 55mL of deionized water and stir until homogeneous. Add 1.7g of modified silver nanowires and stir for 30min. Add 0.9g of carboxyl-polyethylene glycol-carboxyl and stir at 70℃ for 30min. After filtration, wash three times with deionized water and dry in a 70℃ oven for 15min to obtain composite silver nanowires.

[0091] Comparative Example 2

[0092] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0093] 70 parts of nano silver powder, 20 parts of composite silver nanowires, 150 parts of butyl acetate, 100 parts of bisphenol A epoxy resin, 10 parts of hexamethylphthalic anhydride, and 2 parts of 2-methylimidazole.

[0094] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0095] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 600 r / min for 10 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 600 r / min for 20 min to obtain a conductive paste composition.

[0096] The composite silver nanowires are prepared by the following steps:

[0097] A1. 1.7 g of silver nanowires were added to 80 mL of Tris-HCl buffer solution with pH 8.5 and stirred until homogeneous. 0.6 g of dopamine was added and the mixture was stirred at 30 °C for 4 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70 °C for 10 min to obtain polydopamine-modified silver nanowires.

[0098] A2. 1.4 g of polydopamine-modified silver nanowires were added to 50 mL of ethanol and 20 mL of deionized water and stirred until homogeneous. 1 g of γ-aminopropyltriethoxysilane was added and the mixture was stirred at 70 °C for 2 h. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70 °C for 10 min to obtain amino-modified polydopamine-modified silver nanowires.

[0099] A3. Add 2.5g aniline, 3.5g graphene oxide and 3mL of 10% acetic acid solution to 100mL deionized water, stir well, add 0.3g ammonium persulfate and 1.4g ammonium polydopamine modified silver nanowires, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0100] A4. Add 0.9g of hydroxypropyl methylcellulose to 55mL of deionized water and stir until homogeneous. Add 1.7g of modified silver nanowires and stir for 30min. Add 0.9g of carboxyl-polyethylene glycol-carboxyl and stir at 70℃ for 30min. After filtration, wash three times with deionized water and dry in a 70℃ oven for 15min to obtain composite silver nanowires.

[0101] Comparative Example 3

[0102] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0103] 70 parts of nano silver powder, 20 parts of composite silver nanowires, 150 parts of butyl acetate, 100 parts of bisphenol A epoxy resin, 10 parts of hexamethylphthalic anhydride, and 2 parts of 2-methylimidazole.

[0104] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0105] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 600 r / min for 10 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 600 r / min for 20 min to obtain a conductive paste composition.

[0106] The composite silver nanowires are prepared by the following steps:

[0107] A1. 1.7 g of silver nanowires were added to 80 mL of Tris-HCl buffer solution with pH 8.5 and stirred until homogeneous. 0.6 g of dopamine was added and the mixture was stirred at 30 °C for 4 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70 °C for 10 min to obtain polydopamine-modified silver nanowires.

[0108] A2. Add 1.4g of polydopamine-modified silver nanowires and 0.4g of porous zinc oxide nanowires to 85mL of deionized water, stir at 200r / min for 40min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain silver nanowires coated with porous zinc oxide nanowires.

[0109] A3. Add 2.5g aniline, 3.5g graphene oxide and 3mL of 10% acetic acid solution to 100mL of deionized water, stir well, add 0.3g ammonium persulfate and 1.4g porous zinc oxide-coated silver nanowires, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0110] A4. Add 0.9g of hydroxypropyl methylcellulose to 55mL of deionized water and stir until homogeneous. Add 1.7g of modified silver nanowires and stir for 30min. Add 0.9g of carboxyl-polyethylene glycol-carboxyl and stir at 70℃ for 30min. After filtration, wash three times with deionized water and dry in a 70℃ oven for 15min to obtain composite silver nanowires.

[0111] Comparative Example 4

[0112] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0113] 70 parts of nano silver powder, 20 parts of composite silver nanowires, 150 parts of butyl acetate, 100 parts of bisphenol A epoxy resin, 10 parts of hexamethylphthalic anhydride, and 2 parts of 2-methylimidazole.

[0114] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0115] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 600 r / min for 10 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 600 r / min for 20 min to obtain a conductive paste composition.

[0116] The composite silver nanowires are prepared by the following steps:

[0117] A1. 1.7 g of silver nanowires were added to 80 mL of Tris-HCl buffer solution with pH 8.5 and stirred until homogeneous. 0.6 g of dopamine was added and the mixture was stirred at 30 °C for 4 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70 °C for 10 min to obtain polydopamine-modified silver nanowires.

[0118] A2. Add 1.4g of polydopamine-modified silver nanowires and 0.4g of porous zinc oxide nanowires to 85mL of deionized water, stir at 200r / min for 40min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain silver nanowires coated with porous zinc oxide nanowires.

[0119] A3. 1.4 g of porous zinc oxide-coated silver nanowires were added to 50 mL of ethanol and 20 mL of deionized water and stirred until homogeneous. 1 g of γ-aminopropyltriethoxysilane was added and the mixture was stirred at 70 °C for 2 h. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70 °C for 10 min to obtain aminated porous zinc oxide-coated silver nanowires.

[0120] A4. Add 6g of aniline and 3mL of 10% acetic acid solution to 100mL of deionized water, stir well, add 0.3g of ammonium persulfate and 1.4g of aminated porous zinc oxide nano-coated silver nanowires, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0121] A5. Add 0.9g of hydroxypropyl methylcellulose to 55mL of deionized water and stir until homogeneous. Add 1.7g of modified silver nanowires and stir for 30min. Add 0.9g of carboxyl-polyethylene glycol-carboxyl and stir at 70℃ for 30min. After filtration, wash three times with deionized water and dry in a 70℃ oven for 15min to obtain composite silver nanowires.

[0122] Comparative Example 5

[0123] A conductive paste composition reinforced with nano-silver powder filler, comprising the following raw materials in parts by weight:

[0124] 70 parts of nano silver powder, 20 parts of composite silver nanowires, 150 parts of butyl acetate, 100 parts of bisphenol A epoxy resin, 10 parts of hexamethylphthalic anhydride, and 2 parts of 2-methylimidazole.

[0125] A method for preparing a conductive paste composition reinforced with nano-silver powder filler includes the following preparation steps:

[0126] Composite silver nanowires, silver nanopowder, butyl acetate, and bisphenol A epoxy resin were mixed and stirred at 600 r / min for 10 min to obtain a mixture. Hexamethylphthalic anhydride and 2-methylimidazole were added to the mixture and stirred at 600 r / min for 20 min to obtain a conductive paste composition.

[0127] The composite silver nanowires are prepared by the following steps:

[0128] A1. 1.7 g of silver nanowires were added to 80 mL of Tris-HCl buffer solution with pH 8.5 and stirred until homogeneous. 0.6 g of dopamine was added and the mixture was stirred at 30 °C for 4 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 70 °C for 10 min to obtain polydopamine-modified silver nanowires.

[0129] A2. Add 1.4g of polydopamine-modified silver nanowires and 0.4g of porous zinc oxide nanowires to 85mL of deionized water, stir at 200r / min for 40min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain silver nanowires coated with porous zinc oxide nanowires.

[0130] A3. 1.4 g of porous zinc oxide-coated silver nanowires were added to 50 mL of ethanol and 20 mL of deionized water and stirred until homogeneous. 1 g of γ-aminopropyltriethoxysilane was added and the mixture was stirred at 70 °C for 2 h. After cooling to room temperature, the mixture was filtered, washed three times with ethanol and three times with deionized water, and dried in an oven at 70 °C for 10 min to obtain aminated porous zinc oxide-coated silver nanowires.

[0131] A4. Add 2.5g aniline, 3.5g graphene oxide and 3mL of 10% acetic acid solution to 100mL deionized water, stir well, add 0.3g ammonium persulfate and 1.4g aminated porous zinc oxide-coated silver nanowires, stir and react at 2℃ for 1h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain modified silver nanowires;

[0132] A5. Add 1.8g of hydroxypropyl methylcellulose to 55mL of deionized water, stir well, add 1.7g of modified silver nanowires, stir for 30min, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 15min to obtain composite silver nanowires.

[0133] The performance of the conductive paste compositions prepared in Examples 1-3 and Comparative Examples 1-5 was then tested.

[0134] The substrate (polyester film) was ultrasonically cleaned with ethanol for 10 minutes, dried, and then coated with the conductive paste composition prepared above, with a coating amount of 45 g / m. 2 The sample was cured at 100℃ for 100 minutes in an electric thermostatic drying oven. Then, resistivity tests were performed under constant temperature and humidity (25±2℃, 50%RH) conditions. The resistivity test was conducted using a four-probe resistance meter to measure the sheet resistance of the cured slurry electrode. Each sample was tested 5 times, and the average value was recorded.

[0135] System stability test: The conductive paste composition prepared above was placed for 1 day, 7 days and 30 days to observe the stability of the conductive paste composition. The specific evaluation criteria are as follows:

[0136] Good: Precipitation thickness ≤ 0.5 mm, no obvious boundary at the interface after inversion; small viscosity fluctuation (Δη ≤ ±5%), good retention of conductivity (resistivity increase ≤ 5%).

[0137] Poor: Precipitation thickness ≤1mm, interface boundary height after inversion ≤2mm; viscosity fluctuation is controllable (Δη≤±10%), conductivity performance remains normal (resistivity increase ≤10%).

[0138] Poor: The sediment thickness is ≤2mm, visible stratification appears after inversion, and the interface boundary height is ≤5mm; the viscosity increases or decreases significantly (Δη≤±15%), and the conductivity is poorly maintained (resistivity increases by ≤20%).

[0139] Extremely poor performance: precipitation thickness > 2 mm, visible stratification after inversion, interface boundary height > 5 mm; viscosity increases or decreases sharply (Δη > ±15%), and conductivity is poorly maintained (resistivity increases by > 20%).

[0140] The specific test results are shown in Table 1 below.

[0141] Table 1 Performance testing of conductive paste compositions prepared in Examples 1-3 and Comparative Examples 1-5

[0142]

[0143] As can be seen from the data in Table 1, the conductive paste compositions prepared in Examples 1-3 have high stability and conductivity.

[0144] In Comparative Example 1, when polydopamine-modified silver nanowires were replaced with composite silver nanowires prepared from silver nanowires and added to the conductive paste composition, the conductivity decreased. This demonstrates that polydopamine is formed by self-polymerization on the surface of silver nanowires. Polydopamine-modified silver nanowires have excellent adhesion and contain a large number of phenolic hydroxyl groups, which are beneficial for adhering porous nano-zinc oxide to the surface of silver nanowires and improving conductivity.

[0145] In Comparative Example 2, when the porous zinc oxide-coated silver nanowires were replaced with polydopamine-modified silver nanowires, the composite silver nanowires prepared were added to the conductive paste composition. The conductivity of the composite silver nanowires decreased, which proved that the porous zinc oxide was uniformly deposited on the surface of the polydopamine-modified silver nanowires. The composite silver nanowires improved the conductivity of the conductive paste composition and could block oxygen / water molecules from contacting the silver nanowires.

[0146] In Comparative Example 3, replacing the silver nanowires coated with aminated porous zinc oxide nanowires with composite silver nanowires prepared by adding them to the conductive paste composition resulted in a decrease in conductivity. This demonstrates that the grafting of aminosilane onto the surface of the silver nanowires coated with porous zinc oxide nanowires causes graphene oxide and polyaniline to curl along the aminated porous zinc oxide nanowires coated with silver nanowires, forming a tubular structure with the aminated porous zinc oxide nanowires coated with silver nanowires as the core and graphene-polyaniline as the shell. This reduces the overall resistance and improves conductivity.

[0147] In Comparative Example 4, when the composite silver nanowires prepared by replacing graphene oxide with aniline by an equal mass were added to the conductive paste composition, their conductivity decreased. This demonstrates that the graphene oxide nanosheets curl along the silver nanowires coated with aminated porous zinc oxide nanowires. The silver nanowires coated with porous zinc oxide nanowires fill the carbon nanotube structure formed by graphene-polyaniline, forming interconnected conductive pathways with the porous zinc oxide nanowires and silver nanowires, thereby improving conductivity. Furthermore, they can further block oxygen and water molecules from contacting the silver nanowires, thus improving conductivity.

[0148] In Comparative Example 5, when the composite silver nanowires prepared by replacing the carboxyl-polyethylene glycol-carboxyl group with hydroxypropyl methylcellulose by mass were added to the conductive paste composition, their stability and conductivity decreased. This demonstrates that the long-chain molecular structure of the carboxyl-polyethylene glycol-carboxyl group can prevent the sedimentation of the modified silver nanowires and improve the stability of the conductive paste. Furthermore, the modified silver nanowires modified by the carboxyl-polyethylene glycol-carboxyl group can be uniformly dispersed in the conductive paste, improving the dispersion stability of the modified silver nanowires in the conductive paste and enhancing the conductivity.

[0149] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0150] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A conductive paste composition reinforced with nano-silver powder filler, characterized in that, The raw materials include the following parts by weight: 50-70 parts of nano silver powder, 10-20 parts of composite silver nanowires, 110-150 parts of solvent, 80-100 parts of binder, 5-10 parts of curing agent, and 1-2 parts of accelerator; Among them, the composite silver nanowires are obtained by coating the surface of modified silver nanowires with carboxyl-polyethylene glycol-carboxyl and hydroxypropyl methylcellulose; Modified silver nanowires are obtained by depositing porous zinc oxide nanowires on the surface of polydopamine-modified silver nanowires, followed by surface modification with aminosilane, and then reacting them with aniline and graphene oxide. The composite silver nanowires are specifically prepared by the following steps: A1. Add silver nanowires to Tris-HCl buffer solution, stir until homogeneous, add dopamine, stir to react, filter, wash, and dry to obtain polydopamine-modified silver nanowires. A2. Add polydopamine-modified silver nanowires and porous zinc oxide nanowires to deionized water, stir, filter, wash, and dry to obtain silver nanowires coated with porous zinc oxide nanowires. A3. Add the porous zinc oxide-coated silver nanowires to ethanol and deionized water, stir until homogeneous, add γ-aminopropyltriethoxysilane, stir until the reaction is complete, cool to room temperature, filter, wash and dry to obtain aminated porous zinc oxide-coated silver nanowires. A4. Add aniline, graphene oxide and acetic acid solution to deionized water, stir evenly, add ammonium persulfate and silver nanowires coated with aminated porous zinc oxide nanowires, stir to react, filter, wash and dry to obtain modified silver nanowires. A5. Add hydroxypropyl methylcellulose to deionized water and stir until homogeneous. Add modified silver nanowires and stir. Add carboxyl-polyethylene glycol-carboxyl groups and stir at 60-70℃ for 20-30 minutes. After filtration, washing, and drying, composite silver nanowires are obtained.

2. The conductive paste composition reinforced with nano-silver powder filler according to claim 1, characterized in that, In step A1, the ratio of silver nanowires, Tris-HCl buffer solution, and dopamine is (1.2-1.7)g:(60-80)mL:(0.4-0.6)g.

3. The conductive paste composition reinforced with nano-silver powder filler according to claim 1, characterized in that, In step A2, the ratio of polydopamine-modified silver nanowires, porous zinc oxide nanoparticles, and deionized water is (1-1.4)g:(0.2-0.4)g:(75-85)mL.

4. The conductive paste composition reinforced with nano-silver powder filler according to claim 1, characterized in that, In step A3, the ratio of the porous zinc oxide-coated silver nanowires, ethanol, deionized water and γ-aminopropyltriethoxysilane is (1.2-1.4)g:(40-50)mL:(10-20)mL:(0.5-1)g.

5. The conductive paste composition reinforced with nano-silver powder filler according to claim 1, characterized in that, In step A4, the ratio of the amounts of aniline, graphene oxide, acetic acid solution, deionized water, ammonium persulfate, and aminated porous zinc oxide coated silver nanowires is (1.5-2.5)g:(2.5-3.5)g:(1-3)mL:(80-100)mL:(0.1-0.3)g:(1-1.4)g.

6. The conductive paste composition reinforced with nano-silver powder filler according to claim 1, characterized in that, In step A5, the ratio of hydroxypropyl methylcellulose, deionized water, modified silver nanowires, and carboxyl-polyethylene glycol-carboxyl groups is (0.5-0.9)g:(45-55)mL:(1.3-1.7)g:(0.7-0.9)g.

7. The conductive paste composition reinforced with nano-silver powder filler according to claim 1, characterized in that, The solvent includes any one of butyl acetate, ethanol, and n-butanol; The adhesive is bisphenol A epoxy resin with an epoxy equivalent of 180-200.

8. The conductive paste composition reinforced with nano-silver powder filler according to claim 1, characterized in that, The curing agent is selected from either hexamethylphthalic anhydride or maleic anhydride; The accelerator is selected from any one of 2-methylimidazole, 1-benzyl-2-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole.

9. A method for preparing a conductive paste composition reinforced with nano-silver powder filler according to any one of claims 1-8, characterized in that, The preparation steps include the following: Composite silver nanowires, silver nanopowder, solvent, and binder are mixed and stirred at 500-600 r / min for 5-10 min to obtain a mixture. A curing agent and an accelerator are added to the mixture and stirred at 500-600 r / min for 15-20 min to obtain a conductive paste composition.

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