Preparation method of rapid curing conductive adhesive for electronic packaging

Abstract

The invention relates to a preparation method of an adhesive, in particular to a preparation method of a rapid curing conductive adhesive for electronic packaging, which comprises the following steps: firstly, mixing and dispersing 20-35% of modified epoxy resin, 20-50% of modified conductive filler and 0.5-3% of silane coupling agent in a high-speed dispersion machine for 1 hour; adding 15-30% of a curing agent and 1-5% of a curing accelerator, and dispersing for 1 h; and finally, adding 0.3-1.5% of a thickening agent and a proper amount of a defoaming agent, and dispersing for 0.5 h to obtain the rapid curing conductive adhesive. The conductive adhesive is simple to synthesize, environment-friendly and harmless, can be cured within 6-8 seconds at 175-195 DEG C, is uniform in cured adhesive points, has no influence on an antenna and a base material, and has good conductivity, and the shear strength is greater than 50 MPa.

Description

Technical Field

[0001] This invention relates to a method for preparing conductive adhesive, specifically a method for preparing a rapid-curing conductive adhesive for electronic packaging. Background Technology

[0002] Conductive adhesives for microelectronic packaging are functional adhesives that can replace traditional metal solder, offering both adhesion and conductivity. As electronic products become increasingly miniaturized, flexible, and highly integrated, traditional soldering techniques face challenges such as thermal stress damage and limitations in fine-pitch packaging. Conductive adhesives, as a key material, embed conductive fillers into a polymer matrix to achieve mechanical bonding and electrical interconnection of electronic components, becoming an important solution in microelectronic packaging, flexible electronics, and 5G communications.

[0003] Compared to traditional metal welding techniques, conductive adhesives offer advantages such as miniaturization, precision, environmental friendliness, low-temperature operation, and flexibility, enabling the application of temperature-sensitive, low-cost circuit boards. The main components of conductive adhesives are resin, conductive fillers, and curing agents, with the addition of appropriate amounts of curing accelerators, silane coupling agents, defoamers, antioxidants, and other additives to further enhance their performance. Conductive adhesive technology is evolving towards higher conductivity, higher reliability, and multifunctionality. With the integration of nanotechnology, additive manufacturing, and other interdisciplinary fields, it will play a more central role in emerging fields such as three-dimensional heterogeneous integration and flexible hybrid electronics, driving continuous innovation in electronic packaging technology.

[0004] Currently, the curing parameters for conductive adhesives used in electronic packaging are 180~190 ℃ and 10~20 min. Long curing time will not only cause the substrate to deform and age, reduce the interfacial bonding force and degrade the performance, but also increase energy consumption and affect efficiency. Therefore, it is urgent to shorten the curing time of conductive adhesives and improve the production efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a fast-curing conductive adhesive for electronic packaging. This method selects amines or imidazoles as curing agents for the conductive adhesive, forming a three-dimensional network structure. The adhesive decomposes at high temperature, initiating the self-polymerization of epoxy groups or their reaction with hydroxyl groups, thereby enhancing conductivity and toughness. The fast-curing conductive adhesive cures within 6 to 8 seconds at 175 to 195 °C. The cured adhesive dots are uniform, have no impact on antennas or substrates, exhibit excellent conductivity, and have a shear strength greater than 50 MPa.

[0006] The objective of this invention is achieved through the following technical solution: A method for preparing a fast-curing conductive adhesive for electronic packaging is characterized by the following steps: First, 20-35% modified epoxy resin, 20-50% modified conductive filler, and 0.5-3% silane coupling agent are mixed and dispersed in a high-speed disperser for 1 hour; then, 15-30% curing agent and 1-5% curing accelerator are added and dispersed for 1 hour; finally, 0.3-1.5% thickener and an appropriate amount of defoamer are added and dispersed for 0.5 hours to obtain the fast-curing conductive adhesive.

[0007] The aforementioned fast-curing conductive adhesive for electronic packaging is characterized in that the modified conductive filler is one or more of modified spherical nickel powder, modified spherical copper powder, and modified spherical silver powder, with a particle size of 3-5 μm. The modified conductive filler is prepared by adding spherical nickel powder, spherical copper powder, and spherical silver powder to a mixed solution of 10% A-174 (3-(methacryloyloxy)propyltrimethoxysilane) and 10% dopamine hydrochloride, stirring at 800 r / min for 20 min at room temperature, filtering, washing 2-3 times with deionized water and anhydrous ethanol, and drying for 10 h to obtain the surface-modified conductive filler.

[0008] The aforementioned fast-curing conductive adhesive for electronic packaging is characterized in that the epoxy resin is obtained by modification with a thermoplastic polymer, wherein the epoxy resin is one or more of bisphenol A type 127, 128, 114, 115, 116, 134, 1818 and bisphenol F type 150, 151, 161, 162, 165, 170, 175, 1020, preferably bisphenol F type epoxy resin; the thermoplastic polymer is a toughening agent such as polysulfone, polyethersulfone, or polyetherimide; the specific preparation method is as follows: at room temperature, the thermoplastic polymer is dissolved in dichloromethane at a mass ratio of 1:10. After complete dissolution, 20 parts of epoxy resin are added, and the mixture is stirred in an oil bath at 60 ℃ for 3 h to fully mix and evaporate most of the solvent. The product is then transferred to a vacuum drying oven at 120 ℃ and placed for 5 h to completely remove residual solvent. After the sample is removed, it is stored in a cool, dry place for later use to obtain the thermoplastic polymer-modified epoxy resin.

[0009] The fast-curing conductive adhesive for electronic packaging is characterized in that the silane coupling agent is one or more of the following: A-187 (3-(2,3-epoxypropoxy)propyltrimethoxysilane), A-1871 (3-(2,3-epoxypropoxy)propyltriethoxysilane), A-1872 (3-(2,3-epoxypropoxy)propylmethyldiethoxysilane), A-186 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane), and A-1861 (2-(3,4-epoxycyclohexyl)ethyltriethoxysilane).

[0010] The fast-curing conductive adhesive for electronic packaging is characterized in that the curing agent is one or more of 2-undecylimidazole, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazole, dicyandiamide, polyamide, diaminodiphenyl sulfone, and triethanolamine.

[0011] The fast-curing conductive adhesive used in electronic packaging is characterized in that the curing accelerator is one or more of zinc acetylacetonate, copper acetylacetonate, and nano-alumina.

[0012] The fast-curing conductive adhesive for electronic packaging is characterized in that the thickener is nano-SiO2, in which nano-SiO2 also has an anti-settling effect.

[0013] The fast-curing conductive adhesive used in electronic packaging is characterized in that the dispersing device is an integrated dispersing and milling machine with a rotation speed of 400~1000 r / min.

[0014] The fast-curing conductive adhesive for electronic packaging is characterized by curing within 6-8 seconds at 175-195 ℃, producing uniform adhesive dots after curing, having no impact on antennas or substrates, exhibiting excellent conductivity, and having a shear strength greater than 50 MPa.

[0015] The advantages and effects of this invention are: This invention relates to a fast-curing conductive adhesive for electronic packaging. Amines or imidazoles are chosen as curing agents because primary and secondary amines in these compounds can provide active hydrogen atoms (-NH2 or -NH-) to attack the oxygen atoms of the epoxy groups, forming hydroxyl groups through ring-opening and generating new CN bonds, gradually forming a three-dimensional network structure. This structure can decompose at high temperatures, initiating the self-polymerization of epoxy groups or reactions with hydroxyl groups. Conductive particles are modified to enhance conductivity; epoxy resin is modified to enhance toughness. This fast-curing conductive adhesive for electronic packaging cures within 6-8 seconds at 175-195 °C. The cured adhesive dots are uniform, have no impact on antennas or substrates, exhibit excellent conductivity, and have a shear strength greater than 50 MPa.

[0016] It has the following characteristics: 1. The fast-curing conductive adhesive provided by this invention for electronic packaging has advantages such as miniaturization, precision, greenness, low temperature operation, and flexibility compared to traditional metal welding technology, enabling the application of some temperature-sensitive and low-cost circuit boards.

[0017] 2. The fast-curing conductive adhesive provided by this invention for electronic packaging enables mechanical bonding and electrical interconnection of electronic components.

[0018] 3. The fast-curing conductive adhesive for electronic packaging provided by this invention has greatly improved toughness by modifying the epoxy resin with thermoplastic polymer.

[0019] 4. The fast-curing conductive adhesive provided by this invention for electronic packaging has uniform adhesive dots after curing, has no impact on antennas or substrates, and has excellent conductivity. Detailed Implementation

[0020] The present invention will be further described in detail below through embodiments. Example 1

[0021] In this embodiment, the preparation method of the fast-curing conductive adhesive used in electronic packaging is as follows: 1. Preparation of modified conductive particles: Specifically, 200 g of spherical nickel powder with a particle size of 3-5 μm is added to a mixed solution of 10% A-174 (3-(methacryloyloxy)propyltrimethoxysilane) and 10% dopamine hydrochloride. The mixture is stirred at 800 r / min for 20 min at room temperature, filtered, washed 2-3 times with deionized water and anhydrous ethanol, and dried for 10 h to obtain surface-modified nickel powder.

[0022] 2. Preparation of modified epoxy resin: Specifically, 10 g of polysulfone was dissolved in 100 g of dichloromethane at room temperature. After complete dissolution, 200 g of 170 epoxy resin was added, and the mixture was stirred in a 60 ℃ oil bath for 3 h to ensure thorough mixing and evaporate most of the solvent. The product was then transferred to a 120 ℃ vacuum drying oven and left for 5 h to completely remove residual solvent. The sample was then stored in a cool, dry place for later use to obtain the thermoplastic polymer-modified epoxy resin.

[0023] 3. Preparation of a fast-curing conductive adhesive for electronic packaging: First, 100 g of modified epoxy resin, 250 g of modified nickel powder, and 2.5 g of silane coupling agent 1871 are mixed and dispersed in a high-speed disperser for 1 h; then 75 g of dicyandiamide and 5 g of nano-alumina are added and dispersed for 1 h; finally, 1.5 g of nano-SiO2 and an appropriate amount of defoamer are added and dispersed for 0.5 h to obtain a fast-curing conductive adhesive. The speed of the high-speed disperser is 400 r / min.

[0024] 4. The prepared fast-curing conductive adhesive for electronic packaging cures at 195 ℃ for 8 s. The cured adhesive dots are uniform and have no impact on the antenna or substrate. It has excellent conductivity, and the shear force test range is between 50.0 and 80.0 MPa, meeting industry requirements. Example 2

[0025] In this embodiment, the preparation method of the fast-curing conductive adhesive used in electronic packaging is as follows: 1. Preparation of modified conductive particles: Specifically, 200 g of spherical nickel powder with a particle size of 3-5 μm was added to a mixed solution of 10% A-174 (3-(methacryloyloxy)propyltrimethoxysilane) and 10% dopamine hydrochloride. The mixture was stirred at 800 r / min for 20 min at room temperature, filtered, washed 2-3 times with deionized water and anhydrous ethanol, and dried for 10 h to obtain surface-modified nickel powder.

[0026] 2. Preparation of modified epoxy resin: Specifically, 10 g of polyethersulfone was dissolved in 100 g of dichloromethane at room temperature. After complete dissolution, 200 g of 150 epoxy resin was added, and the mixture was stirred in a 60 ℃ oil bath for 3 h to ensure thorough mixing and evaporate most of the solvent. The product was then transferred to a 120 ℃ vacuum drying oven and left for 5 h to completely remove residual solvent. The sample was then stored in a cool, dry place for later use to obtain the epoxy resin modified with the thermoplastic polymer.

[0027] 3. Preparation of a fast-curing conductive adhesive for electronic packaging: First, 175 g of modified epoxy resin, 100 g of modified nickel powder, and 15 g of silane coupling agent 187 are mixed and dispersed in a high-speed disperser for 1 h; then, 150 g of dicyandiamide and 25 g of dicyandiamide curing accelerator are added and dispersed for 10 h; finally, 1.5 g of nano-SiO2 and an appropriate amount of defoamer are added and dispersed for 0.5 h to obtain the fast-curing conductive adhesive. The speed of the high-speed disperser is 1000 r / min.

[0028] 4. The prepared fast-curing conductive adhesive for electronic packaging cures at 190 ℃ for 7 seconds. The cured adhesive dots are uniform, have no impact on antennas or substrates, exhibit excellent conductivity, and the shear force test range is between 50.0 and 70.0 MPa, meeting industry requirements. Example 3

[0029] In this embodiment, the preparation method of the fast-curing conductive adhesive used in electronic packaging is as follows: 1. Preparation of modified conductive particles: Specifically, 200 g of spherical nickel powder with a particle size of 3-5 μm was added to a mixed solution of 10% A-174 (3-(methacryloyloxy)propyltrimethoxysilane) and 10% dopamine hydrochloride. The mixture was stirred at 800 r / min for 20 min at room temperature, filtered, washed 2-3 times with deionized water and anhydrous ethanol, and dried for 10 h to obtain surface-modified nickel powder.

[0030] 2. Preparation of modified epoxy resin: Specifically, 10 g of polysulfone was dissolved in 100 g of dichloromethane at room temperature. After complete dissolution, 200 g of 128 epoxy resin was added, and the mixture was stirred in a 60 ℃ oil bath for 3 h to ensure thorough mixing and evaporate most of the solvent. The product was then transferred to a 150 ℃ vacuum drying oven and left for 5 h to completely remove residual solvent. The sample was then stored in a cool, dry place for later use to obtain the thermoplastic polymer-modified epoxy resin.

[0031] 3. Preparation of a fast-curing conductive adhesive for electronic packaging: First, 150 g of modified epoxy resin, 200 g of modified nickel powder, and 3 g of silane coupling agent 1871 are mixed and dispersed in a high-speed disperser for 1 h; then 100 g of 1-(2-cyanoethyl)-2-ethyl-4-methylimidazolium and 15 g of nano-alumina are added and dispersed for 1 h; finally, 3 g of nano-SiO2 and an appropriate amount of defoamer are added and dispersed for 0.5 h to obtain the fast-curing conductive adhesive. The speed of the high-speed disperser is 900 r / min.

[0032] 4. The prepared fast-curing conductive adhesive for electronic packaging cures at 185 ℃ for 8 s. The cured adhesive dots are uniform and have no impact on the antenna or substrate. It has excellent conductivity, and the shear force test range is between 50.0 and 90.0 MPa, which meets industry requirements. Example 4

[0033] In this embodiment, the preparation method of the fast-curing conductive adhesive used in electronic packaging is as follows: 1. Preparation of modified conductive particles: Specifically, 200 g of spherical silver powder with a particle size of 3-5 μm was added to a mixed solution of 10% A-174 (3-(methacryloyloxy)propyltrimethoxysilane) and 10% dopamine hydrochloride. The mixture was stirred at 800 r / min for 20 min at room temperature, filtered, washed 2-3 times with deionized water and anhydrous ethanol, and dried for 10 h to obtain surface-modified silver powder.

[0034] 2. Preparation of modified epoxy resin: Specifically, 10 g of polyetherimide was dissolved in 100 g of dichloromethane at room temperature. After complete dissolution, 200 g of 170 epoxy resin was added, and the mixture was stirred in a 60 ℃ oil bath for 3 h to ensure thorough mixing and evaporate most of the solvent. The product was then transferred to a 120 ℃ vacuum drying oven and left for 5 h to completely remove residual solvent. The sample was then stored in a cool, dry place for later use to obtain the thermoplastic polymer-modified epoxy resin.

[0035] 3. Preparation of a fast-curing conductive adhesive for electronic packaging: First, 125 g of modified epoxy resin, 200 g of modified silver powder, and 3 g of silane coupling agent 1871 are mixed and dispersed in a high-speed disperser for 1 h; then 120 g of 2-ethyl-4-methylimidazole and 20 g of nano-alumina are added and dispersed for 1 h; finally, 5 g of nano-SiO2 and an appropriate amount of defoamer are added and dispersed for 0.5 h to obtain the fast-curing conductive adhesive. The speed of the high-speed disperser is 500 r / min.

[0036] 4. The prepared fast-curing conductive adhesive for electronic packaging cures at 185 ℃ for 8 s. The cured adhesive dots are uniform and have no impact on the antenna or substrate. It has excellent conductivity and the shear force test range is between 60.0 and 80.0 MPa, meeting industry requirements. Example 5

[0037] In this embodiment, the preparation method of the fast-curing conductive adhesive used in electronic packaging is as follows: 1. Preparation of modified conductive particles: Specifically, 200 g of spherical nickel powder with a particle size of 3-5 μm was added to a mixed solution of 10% A-174 (3-(methacryloyloxy)propyltrimethoxysilane) and 10% dopamine hydrochloride. The mixture was stirred at 800 r / min for 20 min at room temperature, filtered, washed 2-3 times with deionized water and anhydrous ethanol, and dried for 10 h to obtain surface-modified nickel powder.

[0038] 2. Preparation of modified epoxy resin: Specifically, 10 g of polyetherimide was dissolved in 100 g of dichloromethane at room temperature. After complete dissolution, 200 g of 128 epoxy resin was added, and the mixture was stirred in a 60 ℃ oil bath for 3 h to ensure thorough mixing and evaporate most of the solvent. The product was then transferred to a 120 ℃ vacuum drying oven and left for 5 h to completely remove residual solvent. The sample was then removed and stored in a cool, dry place for later use to obtain the thermoplastic polymer-modified epoxy resin.

[0039] 3. Preparation of a fast-curing conductive adhesive for electronic packaging: First, 160 g of modified epoxy resin, 180 g of modified nickel powder, and 12 g of silane coupling agent 187 are mixed and dispersed in a high-speed disperser for 1 h; then, 120 g of 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole and 20 g of nano-alumina are added and dispersed for 1 h; finally, 6 g of nano-SiO2 and an appropriate amount of defoamer are added and dispersed for 0.5 h to obtain the fast-curing conductive adhesive. The speed of the high-speed disperser is 800 r / min.

[0040] 4. The prepared fast-curing conductive adhesive for electronic packaging cures at 190 ℃ for 6 s. The cured adhesive dots are uniform and have no impact on the antenna or substrate. It has excellent conductivity, and the shear force test range is between 60.0 and 90.0 MPa, meeting industry requirements.

Claims

1. A method for preparing a rapid-curing conductive adhesive for electronic packaging, characterized in that, The method includes the following preparation steps: First, mix and disperse 20-35% modified epoxy resin, 20-50% modified conductive filler, and 0.5-3% silane coupling agent in a high-speed disperser for 1 hour; then add 15-30% curing agent and 1-5% curing accelerator and disperse for 1 hour; finally add 0.3-1.5% thickener and an appropriate amount of defoamer and disperse for 0.5 hours to obtain a fast-curing conductive adhesive.

2. A method for preparing a rapid-curing conductive adhesive for electronic packaging according to claim 1, characterized in that, The modified conductive filler is one or more combinations of modified spherical nickel powder, modified spherical copper powder, and modified spherical silver powder, with a particle size of 3~5 μm. The modified conductive filler is prepared by adding spherical nickel powder, spherical copper powder, and spherical silver powder to a mixed solution of 10% A-174 (3-(methacryloyloxy)propyltrimethoxysilane) and 10% dopamine hydrochloride, stirring at 800 r / min for 20 min at room temperature, filtering, washing with deionized water and anhydrous ethanol 2~3 times, and drying for 10 h to obtain the surface-modified conductive filler.

3. A method for preparing a rapid-curing conductive adhesive for electronic packaging according to claim 1, characterized in that, The epoxy resin is obtained by modification with a thermoplastic polymer, wherein the epoxy resin is one or more of bisphenol A type 127, 128, 114, 115, 116, 134, 1818 and bisphenol F type 150, 151, 161, 162, 165, 170, 175, 1020, preferably bisphenol F type epoxy resin; the thermoplastic polymer is polysulfone, polyethersulfone, or polyetherimide toughening agent; the specific preparation method is to dissolve the thermoplastic polymer in dichloromethane at a mass ratio of 1:10 at room temperature, add 20 parts of epoxy resin after complete dissolution, and stir in an oil bath at 60℃ for 3 h to mix thoroughly and evaporate most of the solvent; then transfer the product to a vacuum drying oven at 120℃ and place it for 5 h to completely remove residual solvent; after the sample is taken out, it is stored in a cool and dry place for later use to obtain the thermoplastic polymer modified epoxy resin.

4. A method for preparing a rapid-curing conductive adhesive for electronic packaging according to claim 1, characterized in that, The silane coupling agent is one or more of the following: A-187 (3-(2,3-epoxypropoxy)propyltrimethoxysilane), A-1871 (3-(2,3-epoxypropoxy)propyltriethoxysilane), A-1872 (3-(2,3-epoxypropoxy)propylmethyldiethoxysilane), A-186 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane), and A-1861 (2-(3,4-epoxycyclohexyl)ethyltriethoxysilane).

5. A method for preparing a rapid-curing conductive adhesive for electronic packaging according to claim 1, characterized in that, The curing agent is one or more of 2-undecylimidazole, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazole, dicyandiamide, polyamide, diaminodiphenyl sulfone, and triethanolamine.

6. A method for preparing a rapid-curing conductive adhesive for electronic packaging according to claim 1, characterized in that, The curing accelerator is one or more of zinc acetylacetonate, copper acetylacetonate, and nano-alumina.

7. A method for preparing a rapid-curing conductive adhesive for electronic packaging according to claim 1, characterized in that, The thickener is nano-SiO2, which also serves as an anti-settling agent in the system.

8. The feature of the anti-settlement function according to claim 1 is that, The dispersing device is an integrated dispersing and grinding mill with a rotation speed of 400~1000 r / min.

9. The feature of the anti-settlement function according to claim 1 is that, The curing process involves curing at 175~195 ℃ for 6~8 seconds, and the cured adhesive has a shear strength greater than 50 MPa.