CN-121331536-B - Low-temperature conductive silver paste and preparation method thereof

Abstract

The invention discloses low-temperature conductive silver paste and a preparation method thereof, and relates to the technical field of conductive silver paste. The invention takes a two-dimensional silver nano sheet as a main body, and enables one-dimensional carbon nano tubes to overlap and penetrate in the surface and gaps of the silver nano sheet to form a silver nano sheet reinforcement body through an evaporation self-assembly technology, the carbon nano tube has higher conductivity, the gaps of the silver nano sheet can be filled to achieve the effect of improving the conductivity of silver paste, then, the silver nano sheet reinforcement body and silver nano particles are compounded to form a composite conductive filler, 3, 4-dimethoxy phenethylamine is used for carrying out surface modification on the composite conductive filler, amino groups on 3, 4-dimethoxy phenethylamine molecules can be adsorbed on the surface of the composite conductive filler through coordination, and the existence of benzene rings and methoxy groups increases the steric hindrance among the fillers, so that the dispersion stability is effectively improved, and the conductive property of the conductive silver paste is further enhanced through the uniformity enhancement of a conductive network. The conductive silver paste prepared by the invention has the effects of high conductivity and stability.

Inventors

• ZHANG YE
• WANG HONGGE
• LI ZHOU

Assignees

• 东莞市嘉煜电子材料有限公司

Dates

Publication Date

20260512

Application Date

20251021

Claims (1)

1. 1. The preparation method of the low-temperature conductive silver paste is characterized by comprising the following preparation steps: (1) Adding silver nano-sheets into the carbon nano-tube dispersion liquid, stirring for 10min at room temperature, then heating to 55-65 ℃ for evaporation self-assembly for 55-65min, and repeating the evaporation self-assembly for several times to obtain a silver nano-sheet reinforcement; (2) Mixing the silver nano-sheet reinforcement and silver nano-particles in anhydrous methanol at room temperature, adding 3, 4-dimethoxy phenethylamine under stirring, reacting for 2-3h, filtering, washing and drying to obtain composite conductive filler; (3) Uniformly mixing acrylic resin and a solvent, then adding a composite conductive filler and an auxiliary agent, and stirring for 30-40min at 20-30 ℃ to prepare low-temperature conductive silver paste; the pretreatment of the carbon nanotubes in the step (1) is carried out by treating the carbon nanotubes with a mixed acid solution; The mass ratio of the pretreated carbon nano tube, the accelerator, the deionized water and the silver nano sheet in the step (1) is 1:1:100:5-7; the repetition number in the step (1) is 3-5 times; the promoter in the step (1) is one or two of bacterial cellulose and sodium alginate; The mass ratio of the silver nano-sheet reinforcement to the silver nano-particles to the anhydrous methanol to the 3, 4-dimethoxy phenethylamine in the step (2) is 5:1.8-2.4:30:3-5; In the step (3), the mass ratio of the acrylic resin to the solvent to the auxiliary agent to the composite conductive filler is 10-12:20-26:1-2:60-70.

Description

Low-temperature conductive silver paste and preparation method thereof Technical Field The invention relates to the technical field of conductive silver paste, in particular to low-temperature conductive silver paste and a preparation method thereof. Background The low-temperature conductive silver paste is produced in the dual urgent demands of electronic manufacturing on low-temperature processes and flexible substrates, and the development process can be traced to the rise of flexible electronic technology at the end of the 20 th century. The curing temperature of the traditional high-temperature conductive silver paste is higher than 600 ℃, and metallurgical bonding among silver particles is realized by high-temperature sintering, but the process has extremely high requirements on the temperature resistance of the base material, and limits the application of the process to flexible base materials such as plastics, paper, fabrics and the like. With the rising of the emerging fields of wearable equipment, folding screen mobile phones, printed electronics and the like, a conductive material capable of being cured at low temperature and even at room temperature is urgently needed in the market, so that a thermosensitive substrate is compatible, energy consumption is reduced, development of low-temperature conductive silver paste is developed, and the core breakthrough of the development is that effective connection among silver particles is realized at low temperature through chemical modification or physical regulation. The low-temperature conductive silver paste mainly comprises silver powder, a resin matrix, a solvent and an additive. The silver powder is used as a conductive core and exists in a form of tiny particles, the dispersion is effectively promoted to form a uniform conductive network through optimizing the morphology, the size and the dispersion process, the resin matrix is reasonably selected, the volatility of the solvent is controlled, and a proper amount of auxiliary agent is added, so that the high-efficiency conductivity at a lower temperature is realized, and the requirements of the fields of flexible electronics and the like on the low-temperature processing conductive material are met. Disclosure of Invention The invention aims to provide low-temperature conductive silver paste and a preparation method thereof, which are used for solving the problems in the prior art. The low-temperature conductive silver paste comprises acrylic resin, a composite conductive filler, a solvent and an auxiliary agent, wherein the composite conductive filler is prepared by compounding a silver nano-sheet reinforcement and silver nano-particles with the particle size of 15-20nm and then carrying out surface modification by 3, 4-dimethoxy phenethylamine, the silver nano-sheet reinforcement is formed by taking silver nano-sheets with the sheet diameter of 300-600nm and the thickness of 10-40nm as a main body, and single-wall carbon nano-tubes with the tube diameter of 1-5nm and the length of 20-50 mu m are formed by overlapping and inserting in the surfaces and gaps of the silver nano-sheet reinforcement through an evaporation self-assembly technology. Further, the solvent is one or two of ethyl acetate and cyclohexanone. Further, the auxiliary agent is one or a combination of more of KH560, polyvinylpyrrolidone and sodium dodecyl sulfonate. Further, the preparation method of the low-temperature conductive silver paste comprises the following preparation steps: (1) Adding silver nano-sheets into the carbon nano-tube dispersion liquid, stirring for 10min at room temperature, then heating to 55-65 ℃ for evaporation self-assembly for 55-65min, and repeating the evaporation self-assembly for several times to obtain a silver nano-sheet reinforcement; (2) Mixing the silver nano-sheet reinforcement and silver nano-particles in anhydrous methanol at room temperature, adding 3, 4-dimethoxy phenethylamine under stirring, reacting for 2-3h, filtering, washing and drying to obtain composite conductive filler; (3) Mixing acrylic resin and solvent uniformly, adding composite conductive filler and auxiliary agent, stirring for 30-40min at 20-30 ℃ to obtain the low-temperature conductive silver paste. Further, the pretreatment of the carbon nanotubes in the step (1) is performed by treating the carbon nanotubes with a mixed acid solution. Further, the mass ratio of the pretreated carbon nano tube, the accelerator, the deionized water and the silver nano sheet in the step (1) is 1:1:100:5-7. Further, the repetition number in the step (1) is 3-5. Further, the promoter in the step (1) is one or two of bacterial cellulose and sodium alginate. Further, in the step (2), the mass ratio of the silver nano-sheet reinforcement to the silver nano-particles to the anhydrous methanol to the 3, 4-dimethoxy phenethylamine is 5:1.8-2.4:30:3-5. Further, in the step (3), the mass ratio of the acrylic resin to the solvent to the auxiliary ag