CN-121991626-A - Preparation method of heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive

Abstract

The invention relates to a preparation method of heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive, and relates to the technical field of conductive adhesive. The method comprises the steps of stirring, mixing and stirring flame retardant, low-smog, low-shrinkage rate, self-repairing polyurethane, carbon nano tube dispersion liquid, epoxy resin dispersion, diethylenetriamine, 2-ethyl-4-methylimidazole and acetone to obtain a mixture A, adding an antioxidant, conductive silver powder and a coupling agent into the mixture A to obtain a mixture B, and defoaming the mixture B in vacuum for 10min to obtain the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive, wherein the self-repairing rate of the obtained conductive adhesive is more than 90%, the mass loss rate is lower than 5.72%, the volume resistivity is lower than 4.35 multiplied by 10 ‑5 omega cm, and the conductive adhesive has good heat resistance, high dispersibility, self-repairing and high adhesiveness.

Inventors

• DUAN BAORONG
• XU KE
• DUAN XUCHAO
• Shang Changjian
• WANG QUANJIE
• WANG SHUNPING
• YANG CHENGYU
• LI MINGYU
• Pan Xinrui
• CAO JINYAN
• WANG YANQING
• SONG YUEHAI
• FENG LIANXIANG
• WENG YONGGEN
• SUN LIBO
• NIU RUIYI

Assignees

• 烟台大学
• 长盈新材料(烟台)有限公司

Dates

Publication Date

20260508

Application Date

20260403

Claims (10)

1. 1. The preparation method of the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive is characterized by comprising the following steps of: The method comprises the steps of (1) stirring, mixing and uniformly stirring 20-25 parts of flame-retardant, low-smoke, low-shrinkage, self-repairing polyurethane, 3-7 parts of carbon nano tube dispersion liquid, 3-8 parts of epoxy resin dispersion, 3.0-3.2 parts of diethylenetriamine, 0.8-1 part of 2-ethyl-4-methylimidazole and 16-22 parts of acetone to obtain a mixture A, (2) adding 0.2-0.6 part of antioxidant, 55-65 parts of conductive silver powder and 0.3-1.8 parts of coupling agent into the mixture A, stirring uniformly to obtain a mixture B, (3) defoaming the mixture B for 10min under the vacuum degree of < -0.095MPa to obtain the heat-resistant, high-dispersibility, self-repairing and high-adhesion conductive adhesive; the preparation method of the flame-retardant, low-smoke, low-shrinkage and self-repairing polyurethane comprises the following steps: (1) Taking polypropylene glycol 28 g with the number average molecular weight of 2000 g/mol, isophorone diisocyanate 16.36 g and dibutyltin dilaurate 0.2-0.3 g, adding the mixture into a 500 mL three-neck flask, heating to 70-80 ℃ under the protection of nitrogen, and stirring and reacting for 1-2 hours at the rotating speed of 300 r/min to obtain a polyurethane prepolymer; (2) Adding 1.2g g of 2, 2-dimethylol butyric acid, 1.1-1.5 g of 2, 2-dithiodiethanol and 4.12-5.38 g of nitrogen-phosphorus intumescent flame retardant into the polyurethane prepolymer, reacting for 1-1.5 h at 60-75 ℃, adding 2.1-2.7 g of triethylamine, continuing to react for 0.5-1 h, cooling to room temperature, adding 70 mL of deionized water, shearing and emulsifying for 0.5 h at a high speed at a rotating speed of 2000 r/min, adding 7-8 g of epoxy resin E and 3-5 g of softener, stirring for 0.25-0.5 h at 500 r/min, dispersing uniformly, and distilling under reduced pressure until the solid content is 70%, thereby obtaining the flame retardant, low-smoke and low-shrinkage self-repairing polyurethane.
2. 2. The preparation method of the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive is characterized in that 0.3-0.5 g of chloroplatinic acid and 7-9 g of isopropanol are added into a four-neck flask, the temperature is raised to 70-80 ℃, 2.1 g g of hydrogen-terminated silicone oil and 25-31 g of allyl epoxy polyether are slowly added dropwise, the dropwise adding time is 1h, the pH of a glacial acetic acid regulating system is 5-6, the reaction is carried out for 3-5 hours at 90-100 ℃ to obtain an intermediate A, 400-12 g of polyetheramine D and 1.1-2.2 g of ethylboric acid are added into the intermediate A, the pH of the system is maintained to 5-6, the reaction is carried out for 2-5 hours at 70-90 ℃, and the softener is obtained after cooling.
3. 3. The method for preparing the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive according to claim 1, wherein the method for preparing the epoxy resin dispersion is characterized in that 3-5 g of hexagonal boron nitride is added into 20 g furfuryl alcohol glycidyl ether, uniformly dispersed hexagonal boron nitride dispersion liquid is obtained by ultrasonic treatment in ice water bath for 1-2 hours, 100-120 g of epoxy resin E is added, and stirring is carried out for 0.5-1.0 hour at 500-1000 r/min, so that the epoxy resin dispersion is obtained.
4. 4. The method for preparing a heat-resistant, highly dispersible, self-repairing, highly adhesive conductive paste according to claim 3, wherein the hexagonal boron nitride has a particle size of 100 nm.
5. 5. The method for preparing the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive according to claim 1, wherein the method for preparing the nitrogen-phosphorus intumescent flame retardant is as follows: (1) Adding 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide of 21.6 g and maleic anhydride of 9.8 g into a four-necked flask by taking 100 mL tetrahydrofuran as a solvent, stirring and reacting for 3-6 h in a 50 ℃ oil bath pot, and drying by a vacuum oven to obtain an intermediate B; (2) Adding 13.3 g diisopropanolamine and 0.43 g p-toluenesulfonic acid into the intermediate B, adding toluene until immersing reactants, heating in an oil bath at 100 ℃ for reaction for 3-6 h, and vacuum drying at 70-85 ℃ until the weight is constant to obtain an intermediate C; (3) Adding 60.9 g of tetrakis (hydroxymethyl) phosphonium sulfate into the product obtained in the step (2), reacting for 1-2 h, and vacuum drying at 70-85 ℃ to constant weight to obtain a tetrakis (hydroxymethyl) phosphonium sulfate modified flame retardant; (4) Adding 4.6-5.2 g of diethyl thiophosphoryl chloride into the tetrakis (hydroxymethyl) phosphonium sulfate modified flame retardant obtained in the step (3), stirring and reacting for 1-2 hours at 70-80 ℃, adding 5.2-5.8 g of zirconium sulfate, 0.21-0.35 g of aspartic acid, 0.13-0.32 g of 1H-indole-2-carboxamide and 5-8 g of water, reacting for 0.25-0.5 hours at 45-65 ℃, and vacuum drying to constant weight to obtain the nitrogen-phosphorus intumescent flame retardant with a branched structure.
6. 6. The method for preparing the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive according to claim 1, wherein the conductive silver powder consists of flake silver powder and spherical silver powder according to a weight ratio of 3:1-4:1.
7. 7. The preparation method of the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive according to claim 1, which is characterized in that 1g carbon nanotubes, 0.2-0.3 g of ultra-long carbon nanotubes and 1.1-1.5 g of dispersing agent are added into 65 g deionized water, the carbon nanotubes are completely wetted by stirring at 500-1000 r/min, 1.5-2.7 g of p-hydroxybenzaldehyde is added, the mixture is further dispersed by an ultrasonic cell pulverizer, the output power is 600-700W, the ultrasonic dispersion time is 10-50 min, and the dispersion is subjected to centrifugal treatment at the rotating speed of 1000-1200 r/min for 10-30 min, so that the carbon nanotube dispersion is obtained.
8. 8. The method for preparing the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive according to claim 7, wherein the dispersing agent is prepared by mixing sodium glycocholate, glycerol, dodecyl dimethyl betaine and aminoacetic acid according to a weight ratio of 4:1:0.2-0.5:0.3-0.35.
9. 9. The method for preparing the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive according to claim 1, wherein the coupling agent is any one of KH550 and KH560 or a mixture of the two in any proportion.
10. 10. The method for preparing the heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive according to claim 1, wherein the antioxidant is any one or a mixture of any two of benzotriazole and antioxidant 1010 in any proportion.

Description

Preparation method of heat-resistant, high-dispersibility, self-repairing and high-adhesiveness conductive adhesive Technical Field The invention relates to the technical field of conductive adhesive, in particular to a preparation method of heat-resistant, high-dispersity, self-repairing and high-adhesiveness conductive adhesive. Background With the continuous development of electronic technology, especially in high-frequency, high-density, miniaturized electronic devices, conventional solder materials face many challenges. Although solder is widely used in electronic assembly, it is difficult to meet long-term stability and reliability requirements in certain specific application scenarios. Particularly in the application with high performance, vibration resistance and high frequency stability, the soldering tin is easy to generate fatigue failure, thermal stress problem, conductive performance decline and the like. The conductive adhesive is an adhesive which is cured or dried and has conductivity, and can connect various conductive materials together so as to form an electric path between the connected materials. In the electronics industry, conductive adhesives have become an indispensable key material. As a substitute for solder, conductive paste is becoming a core technology in high-performance electronic assembly due to its excellent conductivity, good temperature resistance and operational flexibility. The conductive adhesive can replace soldering tin in the traditional welding process, and can effectively solve the problems of thermal damage, welding defects and the like in the welding process. The conductive adhesive is generally composed of a conductive filler, an adhesive matrix, a solvent and an additive. Wherein, the filler is mainly silver, copper, gold, nickel and carbon materials, silver powder is the most commonly used at present, the adhesive matrix is commonly used with epoxy resin, silicon rubber, polyurethane, acrylic ester and the like, the epoxy resin is the main at present, and the solvent is commonly used with water, alcohols, ketones, esters and the like. The epoxy resin matrix has higher adhesiveness and heat resistance, and is mainly used for precise chip bonding, printed circuit board element bonding, rigid connection of metal electrodes and conductive connection in a high-temperature environment. However, in the fields of flexibility (toughness is required, such as reinforcement of a flexible circuit), high requirements on anti-vibration performance (such as an automobile sensor in a vibration environment), elastic compression and rebound (such as adhesion of an electromagnetic shielding gasket) and the like, the epoxy resin adhesive is difficult to meet the use requirement. Polyurethane glue has good folding endurance, but has the problems of insufficient heat resistance, lower adhesiveness than epoxy resin glue and the like. Therefore, in the field of flexible circuits for which toughness is sought, polyurethane adhesives are required to be further improved in heat resistance and adhesion. The invention patent CN119799117B is characterized in that a specific solvent is used for preliminarily disentangling the carbon nano tube to prepare a carbon nano tube dispersion liquid with uniform dispersion, polyaniline is added into the carbon nano tube dispersion liquid, the carbon nano tube/polyaniline composite is prepared through solvent evaporation or purification, and finally the composite is compounded with epoxy resin to obtain the carbon nano tube/polyaniline composite modified epoxy resin conductive coating. Compared with the traditional conductive paint, the conductive paint has more excellent mechanical property and electrical property, and can be better applied to the fields of aerospace, batteries, communication, new energy sources and the like. The patent solves the dispersion stability problem of the carbon nanotubes, but does not relate to the cracking condition of the epoxy resin composite material under the repeated stretching and bending conditions, and does not relate to the heat resistance and the combustion smoke performance of the composite material. The invention patent CN120173542B discloses a conductive adhesive, a preparation method and application thereof, wherein the conductive adhesive is prepared by stirring and reacting synthetic acrylic resin, epoxy resin, conductive filler, latent curing auxiliary agent, diluent and auxiliary agent. According to the invention, the latent curing auxiliary agent is added, so that the possibility of reaction of the acrylic resin and the epoxy resin at normal temperature is reduced, the storage stability of the conductive adhesive is improved, and meanwhile, the integral performance of the electronic product is improved, and the requirements of different application scenes are met. The preparation method has the advantages that the raw materials are directly and uniformly mixed, separation and storage are not needed, th