Low shrinkage epoxy resin conductive paste and preparation method thereof

Abstract

This application provides a low-shrinkage epoxy resin conductive paste and its preparation method. The preparation method includes: weighing and obtaining multiple raw material components according to a preset ratio; wherein, the multiple raw material components include 80wt% silver powder, 16wt% alicyclic epoxy resin, 2wt% diluent, 1.1wt% curing agent, 0.3wt% dispersant, and 0.6wt% coupling agent; mixing the multiple raw material components uniformly according to a preset shear force at a preset ambient temperature to obtain a raw material mixture; grinding the raw material mixture at least three times using a three-roll mill. The resulting epoxy resin conductive paste can be stored for a long time at room temperature and dried rapidly at low temperature, while controlling the volume shrinkage during its curing process, thereby improving the adhesion between the epoxy resin conductive paste and the substrate and other coatings, and improving the stability of the conductive circuit.

Description

Technical Field

[0001] This application relates to the technical field of conductive materials, specifically to a low-shrinkage epoxy resin conductive paste and its preparation method. The prepared epoxy resin conductive paste can be applied to the technical field of chip packaging. Background Technology

[0002] Epoxy resin is widely used in the preparation of conductive pastes due to its excellent adhesion, heat resistance, and good insulation properties, serving as an important component of binders and organic carriers. In conductive paste systems, epoxy resin mainly forms a three-dimensional network structure through a cross-linking reaction with the curing agent, thereby fixing the silver powder particles in the matrix. During sintering, volume shrinkage further strengthens the contact between the silver powder particles, reducing contact resistance and improving conductivity.

[0003] In existing technologies, bisphenol A type epoxy resin is the most widely used resin in conductive pastes. Its structure contains two benzene rings and one epoxy group, exhibiting high reactivity and crosslinking density. However, this structural characteristic also leads to a large volume shrinkage rate during curing. Studies have shown that the curing shrinkage rate of the resin directly affects the spacing between silver powder particles, thus significantly impacting the conductivity of the conductive paste. When the volume shrinkage rate is too large, the contact points between silver powder particles may be excessively compressed, leading to localized stress concentration and even displacement or detachment of silver powder particles, thereby affecting the adhesion between the silver paste and the substrate and the stability of the conductive pathway.

[0004] In addition, the high shrinkage rate of bisphenol A epoxy resin may also cause stress cracking or microcracks inside the silver paste coating. Especially during high-temperature curing or long-term service, these problems will further weaken the mechanical properties and electrical reliability of the silver paste. Summary of the Invention

[0005] The purpose of this application is to overcome the shortcomings and deficiencies in the prior art and to provide a low-shrinkage epoxy resin conductive paste and its preparation method.

[0006] The first aspect of this application provides a method for preparing a low-shrinkage epoxy resin conductive paste, comprising:

[0007] Weigh and obtain various raw material components according to a preset ratio; wherein, the various raw material components include 80wt% silver powder, 16wt% alicyclic epoxy resin, 2wt% diluent, 1.1wt% curing agent, 0.3wt% dispersant and 0.6wt% coupling agent.

[0008] At a preset ambient temperature, the various raw material components are mixed evenly according to a preset shear force to obtain a raw material mixture;

[0009] The raw material mixture is ground at least three times using a three-roll mill to obtain an epoxy resin conductive paste.

[0010] In one embodiment, the average particle size of the silver powder is below 10.00µm.

[0011] In one embodiment, small-particle-size flake silver powder is added to the silver powder.

[0012] As one implementation method, the curing agent is selected through the following steps:

[0013] Construct an evaluation table for various cationic curing agents to assess their curing behavior, bond strength, thermal stability, and storage stability under the same or different heating conditions;

[0014] Based on the application requirements of the epoxy resin conductive paste, the corresponding cationic curing agent is obtained from the curing agent evaluation table as the curing agent in the raw material components.

[0015] As one implementation method, the step of obtaining the corresponding cationic curing agent as the curing agent in the raw material component includes:

[0016] If the epoxy resin conductive paste is used to bond materials with low heat resistance requirements, AE-100 cationic curing agent is used as the curing agent in the raw material components.

[0017] If the epoxy resin conductive paste is used for bonding metal and plastic, AE-400 cationic curing agent is used as the curing agent in the raw material components;

[0018] If the epoxy resin conductive paste is used for bonding in high-precision, confined spaces, AE-700 cationic curing agent is used as the curing agent in the raw material components.

[0019] A second aspect of this application provides a low-shrinkage epoxy resin conductive paste, which is prepared by a variety of raw material components; the variety of raw material components includes 80 wt% silver powder, 16 wt% alicyclic epoxy resin, 2 wt% diluent, 1.1 wt% curing agent, 0.3 wt% dispersant and 0.6 wt% coupling agent.

[0020] In one embodiment, the average particle size of the silver powder is below 10.00µm.

[0021] In one embodiment, small-particle-size flake silver powder is added to the silver powder.

[0022] As one implementation method, the curing agent is selected through the following steps:

[0023] Construct an evaluation table for various cationic curing agents to assess their curing behavior, bond strength, thermal stability, and storage stability under the same or different heating conditions;

[0024] Based on the application requirements of the epoxy resin conductive paste, the corresponding cationic curing agent is obtained from the curing agent evaluation table as the curing agent in the raw material components.

[0025] As one implementation method, the step of obtaining the corresponding cationic curing agent as the curing agent in the raw material component includes:

[0026] If the epoxy resin conductive paste is used to bond materials with low heat resistance requirements, AE-100 cationic curing agent is used as the curing agent in the raw material components.

[0027] If the epoxy resin conductive paste is used for bonding metal and plastic, AE-400 cationic curing agent is used as the curing agent in the raw material components;

[0028] If the epoxy resin conductive paste is used for bonding in high-precision, confined spaces, AE-700 cationic curing agent is used as the curing agent in the raw material components.

[0029] Compared with related technologies, the epoxy resin conductive paste prepared by this application using alicyclic epoxy resin can be stored for a long time at room temperature and dried rapidly at low temperature. At the same time, the volume shrinkage during its curing process is controlled, thereby improving the adhesion between the epoxy resin conductive paste and the substrate and other coatings, and improving the stability of the conductive circuit. Therefore, the epoxy resin conductive paste prepared by this application can be applied to the field of chip packaging technology.

[0030] To provide a clearer understanding of this application, the specific embodiments of this application will be described below in conjunction with the accompanying drawings. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating a method for preparing epoxy resin conductive paste according to an embodiment of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0033] It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0034] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. The singular forms "a," "the," and "the" used in this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. The word "if" as used herein can be interpreted as "when," "when," or "in response to determination."

[0035] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0036] Please see Figure 1 This is a flowchart of a method for preparing epoxy resin conductive paste according to the first embodiment of this application. The method includes:

[0037] S1: Weigh and obtain various raw material components according to the preset proportions; wherein, the various raw material components include 80wt% silver powder, 16wt% alicyclic epoxy resin, 2wt% diluent, 1.1wt% curing agent, 0.3wt% dispersant and 0.6wt% coupling agent;

[0038] S2: Under a preset ambient temperature and according to a preset shear force, the various raw material components are mixed evenly to obtain a raw material mixture;

[0039] It should be noted that excessively high temperatures may cause the resin or curing agent to react prematurely, shortening the pot life; while excessive shear force will damage the sheet-like structure of the silver powder and affect the formation of conductive paths. Therefore, in this embodiment, the preset ambient temperature is ≤50℃, and the preset shear force is set by the user, who can adjust the shear force according to the actual mixing situation.

[0040] S3: Grind the raw material mixture at least three times using a three-roll mill to obtain an epoxy resin conductive paste.

[0041] The above mixing process can effectively improve the dispersion uniformity of silver powder in epoxy resin conductive paste, thereby enhancing its conductivity and adhesion strength, and providing a reliable guarantee for subsequent printing, curing and application.

[0042] The alicyclic epoxy resin used in this remarkable application is a significant branch of epoxy resins. As a matrix material, alicyclic epoxy resins offer significant advantages in electronic packaging, bonding, and composite materials, exhibiting superior overall performance compared to other types of epoxy resins in numerous applications. Firstly, alicyclic epoxy resins exhibit low volume shrinkage during curing, typically only 1-2%, a characteristic far superior to aromatic epoxy resins and other thermosetting resins. This effectively reduces problems such as cracking, bubbling, or interfacial delamination caused by shrinkage stress during curing, thereby improving the overall stability and reliability of the material. Secondly, the molecular structure of alicyclic epoxy resins is primarily composed of saturated carbon chains and lacks aromatic rings, resulting in excellent heat resistance and dimensional stability. Furthermore, it maintains good mechanical properties even at high temperatures, making it suitable for applications requiring high thermal stability. In addition, alicyclic epoxy resins typically have low dielectric constants and dielectric losses, making them promising for applications in high-frequency electronic devices and insulating materials. Compared to aromatic epoxy resins, alicyclic epoxy resins exhibit superior resistance to yellowing under ultraviolet light irradiation, effectively extending the material's lifespan. In terms of adhesion, alicyclic epoxy resins exhibit excellent wettability and adhesion to various substrates (such as metals, ceramics, and glass), achieving high-strength and durable bonding. Furthermore, due to their mild curing reaction and low heat release, they are suitable for encapsulation and bonding processes of heat-sensitive materials. In electronic materials such as epoxy conductive pastes, alicyclic epoxy resins, when used as the matrix resin, are well-compatible with silver powder and other functional fillers, contributing to the formation of a uniform conductive network and thus improving conductivity.

[0043] In summary, alicyclic epoxy resins have significant advantages in terms of shrinkage, thermal stability, dielectric properties, and adhesive properties. Compared with other types of epoxy resins, they show broader application potential in high-end electronic packaging, precision bonding, and composite material preparation.

[0044] In one feasible embodiment, the average particle size of the silver powder is below 10.00 µm.

[0045] Silver powder, as a key conductive filler in epoxy resin conductive paste, has a significant impact on the conductivity, adhesion, and mechanical strength of the final product due to its particle size, shape, and content. Studies have shown that when the average particle size of silver powder is below 10.00µm, the particle distribution tends to be normal, resulting in a densely packed state, which is conducive to forming continuous conductive pathways and thus improving conductivity.

[0046] In one feasible embodiment, the silver powder contains small-particle-size flake silver powder with a particle size of less than 1.00µm.

[0047] When the particle size is further reduced to below 1.00µm, if the degree of flake formation is poor, the contact area between silver powder particles decreases, leading to a decline in conductivity. Therefore, in practical applications, a balance needs to be struck between particle size and degree of flake formation. For example, adding an appropriate amount of silver powder with a particle size of less than 1.00µm and good flake formation to large-particle-size silver powder (maximum particle size less than 10.00µm) can improve conductivity and enhance adhesion, achieving optimal performance. This composite particle size system not only increases the packing density of the silver powder but also enhances the continuity of the conductive network.

[0048] Furthermore, the shape of the silver powder also significantly affects its conductivity. Flake-shaped silver powder, due to its larger aspect ratio and lower packing density, can more effectively form conductive channels, thus exhibiting superior conductivity at the same content. In contrast, while spherical silver powder has a higher packing density, its fewer contact points and less continuous conductive path result in relatively weaker conductivity. Therefore, in the formulation design of epoxy resin conductive pastes, flake-shaped silver powder should be prioritized, and its degree of flake formation should be reasonably controlled according to actual needs.

[0049] It should be noted that the amount of silver powder added is another key factor affecting the performance of epoxy resin conductive paste. Appropriately increasing the silver powder content helps improve conductivity, but excessive addition may lead to increased system viscosity, affecting processing performance, and even causing silver powder agglomeration, thus reducing conductivity efficiency. Therefore, the particle size, shape, and dispersibility of the silver powder should be considered in the formulation design. This application optimizes the addition ratio of small-particle-size flake silver powder through experiments to achieve a balance between conductivity and processing performance.

[0050] In the formulation of single-component epoxy conductive paste using alicyclic epoxy resin as a carrier, cationic curing agents play a crucial role. Their main function is to initiate the ring-opening reaction of epoxy groups, thereby driving the resin system from a liquid to a solid state. Cationic curing agents are typically Lewis acid compounds, such as boron trifluoride amine complexes and organotin compounds. Under heating conditions, they release active cations. These cations act as initiators, attacking the oxygen atoms in the epoxy groups, initiating a chain reaction that causes cross-linking between epoxy resin molecules, ultimately forming a three-dimensional network structure. This process not only determines the initiation and progression of the curing reaction but also directly affects key performance indicators such as curing rate and shrinkage rate.

[0051] The curing rate is mainly affected by factors such as the type and dosage of the cationic curing agent and the reaction temperature. Higher activity of the cationic curing agent results in a stronger ability to initiate epoxy group reactions, thus significantly accelerating the curing process. For example, some highly efficient cationic curing agents can rapidly initiate reactions at lower temperatures, allowing epoxy resins to cure quickly. This is significant for applications requiring rapid curing, such as the preparation of low-temperature epoxy conductive pastes. Furthermore, the dosage of the curing agent is also closely related to the curing rate. Appropriately increasing the curing agent content can increase the number of active initiation sites in the reaction system, thereby accelerating the reaction rate. However, excessive addition may lead to an overly vigorous reaction, causing problems such as localized overheating or structural inhomogeneity, which is detrimental to performance optimization.

[0052] Meanwhile, cationic curing agents also significantly affect the volume shrinkage rate during the curing process. During curing, the resin system undergoes volume shrinkage as epoxy groups react and cross-linking structures form. This shrinkage behavior is particularly critical in precision materials such as epoxy conductive pastes, as excessive shrinkage can lead to changes in the spacing between silver powder particles, thus affecting the stability and electrical properties of the conductive network. Cationic curing agents can control the degree of shrinkage to some extent by regulating the reaction rate and cross-linking density. For example, some low-activity or delayed-type cationic curing agents can slowly release active ions over a longer period, making the curing process gentler, thereby reducing the volume shrinkage rate and improving the dimensional stability and electrical conductivity of the material. Furthermore, some specially designed cationic curing agents can form a more uniform cross-linking structure with resin molecules, reducing local stress concentration and further suppressing the adverse effects of shrinkage.

[0053] Therefore, cationic curing agents not only determine the initiation and rate of reaction during epoxy resin curing, but also have a profound impact on the structure and properties of the cured product. By rationally selecting the type of curing agent and controlling its dosage, the curing rate and shrinkage rate can be effectively regulated, thereby meeting the performance requirements of different application scenarios. This is particularly valuable in the development of low-temperature curing, low-shrinkage epoxy resin conductive pastes.

[0054] In summary, in one feasible embodiment, the curing agent is selected through the following steps:

[0055] S01: Construct a curing agent evaluation table to assess the curing behavior, bond strength, thermal stability, and storage stability of various cationic curing agents under the same or different heating conditions;

[0056] The curing agent evaluation table is constructed based on experimental results of various cationic curing agents. During the experiments, the cationic curing agents typically undergo a ring-opening reaction with epoxy groups under specific conditions via photoinitiation or thermal initiation, thereby achieving resin curing. Ideally, a cationic curing agent should exhibit good storage stability at low temperatures, avoiding unexpected reactions with epoxy resins at room temperature, while being rapidly activated and completing the curing reaction upon heating.

[0057] S02: Based on the application requirements of the epoxy resin conductive paste, obtain the corresponding cationic curing agent from the curing agent evaluation table as the curing agent in the raw material components.

[0058] By comparing the curing behavior, bond strength, thermal stability, and storage stability of different cationic curing agents under the same or different heating conditions, their applicability can be systematically evaluated, and the optimal type and dosage of curing agent can be determined accordingly. This provides a scientific basis and technical support for the development of high-performance single-component epoxy resin adhesives.

[0059] In a feasible embodiment, S02: the step of obtaining the corresponding cationic curing agent as the curing agent in the raw material component includes:

[0060] S021: If the epoxy resin conductive paste is used to bond materials with low heat resistance requirements, AE-100 cationic curing agent shall be used as the curing agent in the raw material components.

[0061] S022: If the epoxy resin conductive paste is used for bonding metal and plastic, AE-400 cationic curing agent is used as the curing agent in the raw material components.

[0062] S023: If the epoxy resin conductive paste is used for bonding in high-precision, confined spaces, AE-700 cationic curing agent shall be used as the curing agent in the raw material components.

[0063] Specifically, taking the "AE-100," "AE-400," and "AE-700" series of one-component epoxy resin adhesives developed by Ajinomoto Fine Chemicals Co., Ltd. as examples, an evaluation table of corresponding curing agents was constructed through experiments. AE-100 can achieve rapid curing at 60°C while maintaining a long shelf life, indicating good inertness at low temperatures and high reactivity after heating. In contrast, AE-400, while maintaining similar curing performance, incorporates a rubber elastic component, resulting in higher peel strength in bonding different materials such as metals and plastics. This demonstrates that the type of cationic curing agent not only affects curing efficiency but also significantly impacts the mechanical properties of the adhesive interface. Furthermore, AE-700 uses a fully liquid formulation; its curing agent is completely miscible with the epoxy resin at the molecular level but does not react at room temperature. This indicates that the selected cationic curing agent has extremely high thermal responsiveness, enabling rapid initiation of the curing process under heating conditions, thus demonstrating advantages in applications requiring high impregnation performance, such as motor winding seals.

[0064] A second aspect of this application provides a low-shrinkage epoxy resin conductive paste, which is prepared by a variety of raw material components; the variety of raw material components includes 80 wt% silver powder, 16 wt% alicyclic epoxy resin, 2 wt% diluent, 1.1 wt% curing agent, 0.3 wt% dispersant and 0.6 wt% coupling agent.

[0065] In one feasible embodiment, the average particle size of the silver powder is below 10.00 µm.

[0066] In one feasible embodiment, small-particle-size flake silver powder is added to the silver powder.

[0067] In one feasible embodiment, the curing agent is selected through the following steps:

[0068] Construct an evaluation table for various cationic curing agents to assess their curing behavior, bond strength, thermal stability, and storage stability under the same or different heating conditions;

[0069] Based on the application requirements of the epoxy resin conductive paste, the corresponding cationic curing agent is obtained from the curing agent evaluation table as the curing agent in the raw material components.

[0070] In one feasible embodiment, the step of obtaining the corresponding cationic curing agent as the curing agent in the raw material component includes:

[0071] If the epoxy resin conductive paste is used to bond materials with low heat resistance requirements, AE-100 cationic curing agent is used as the curing agent in the raw material components.

[0072] If the epoxy resin conductive paste is used for bonding metal and plastic, AE-400 cationic curing agent is used as the curing agent in the raw material components;

[0073] If the epoxy resin conductive paste is used for bonding in high-precision, confined spaces, AE-700 cationic curing agent is used as the curing agent in the raw material components.

[0074] The conductivity of epoxy resin conductive paste is a crucial indicator for evaluating its performance in flexible electronics, printed circuits, and other related applications. To accurately assess the conductivity of the epoxy resin conductive paste prepared in this application, a resistivity test method was used for quantitative analysis. According to relevant research, the formula for calculating resistivity ρ (in Ω·cm) is ρ = R × W × H / L, where R is the measured resistance (Ω), W is the width of the conductive line (cm), H is the thickness of the line (cm), and L is the length of the line (cm). In practical testing, the sheet resistance (in mΩ / □) of the conductive block is often measured using a four-probe tester, and the film thickness (in µm) is measured using a film thickness meter. The conductivity is then calculated using the formula ρ = R × D, where R is the sheet resistance and D is the film thickness.

[0075] In addition, the conductivity of the silver paste under different curing conditions needs to be monitored during the testing process. In the experiment, the silver paste was printed onto a PET substrate and cured at 135°C for 3 minutes, followed by conductivity testing. The test results showed that the conductivity of the silver paste is not only affected by the silver powder content, but also closely related to the type of resin.

[0076] In practical applications, the conductivity of epoxy resin conductive paste can also be affected by environmental factors, such as temperature and humidity. Therefore, standardization of test conditions is crucial to ensuring the comparability and repeatability of test results. In this study, all tests were conducted under a standard environment of 25°C to ensure the accuracy and consistency of the test results.

[0077] Besides conductivity, the adhesion of the epoxy resin conductive paste prepared in this application can be tested through methods such as pull-out tests. The adhesion of the epoxy resin conductive paste is of great significance in fields such as flexible electronic devices, touch screens, and conductive circuit printing. The quality of adhesion directly affects the stability, conductivity, and service life of the epoxy resin conductive paste in practical applications. For example, the adhesion of the epoxy resin conductive paste to ITO / PET conductive films is evaluated using the cross-cut adhesion test (according to GB9286-98 standard). The test results are classified into grades from 5B to 0B, where 5B indicates no peeling and the best adhesion, while 0B indicates complete peeling and the worst adhesion. Pull-out tests further verify its adhesion strength, simulating external force peeling conditions that may be encountered in practical applications, thereby providing a more comprehensive evaluation of its adhesion performance.

[0078] In the fields of materials science and electronic manufacturing, epoxy conductive paste, as a key bonding material, is widely used in the conductive circuit printing and packaging processes of electronic devices. Its performance not only affects the conductivity and stability of electronic devices but also directly relates to their long-term reliability. Among these factors, the shrinkage behavior of epoxy conductive paste during curing is a significant influence on its structural stability and interfacial bonding strength. Therefore, measuring the shrinkage rate of epoxy conductive paste after curing is crucial for optimizing its formulation design and process parameters. In recent years, low-shrinkage epoxy resins have been widely used as matrix materials for epoxy conductive pastes due to their advantages such as small volume changes and good thermal stability during curing. By introducing low-shrinkage epoxy resins, the volume shrinkage of silver paste during curing can be effectively reduced, thereby reducing defects such as cracks and voids caused by shrinkage stress and improving the bonding strength between the silver paste and the substrate. To verify the application effect of low-shrinkage epoxy resins, researchers typically use thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dimensional measurements to systematically evaluate the volume changes of silver paste samples before and after curing. Experimental results show that, under the same curing conditions, epoxy conductive paste using low-shrinkage epoxy resin as the matrix exhibits a significantly lower shrinkage rate than traditional epoxy resin systems, and its conductivity and mechanical properties are significantly improved. Furthermore, low-shrinkage epoxy resin can effectively improve the dimensional stability of silver paste at high temperatures and reduce interfacial stress generated during thermal cycling, thereby enhancing the durability and reliability of electronic devices. Therefore, measuring the shrinkage rate of cured epoxy conductive paste is not only an important means of evaluating material properties but also provides a scientific basis for further optimizing the application of low-shrinkage epoxy resin. Through systematic research and experimental verification, the application of low-shrinkage epoxy resin in epoxy conductive paste demonstrates promising prospects and provides a new direction for the development of high-performance electronic materials.

[0079] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0080] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for preparing a low-shrinkage epoxy resin conductive paste, characterized in that, include: Weigh and obtain various raw material components according to a preset ratio; wherein, the various raw material components include 80wt% silver powder, 16wt% alicyclic epoxy resin, 2wt% diluent, 1.1wt% curing agent, 0.3wt% dispersant and 0.6wt% coupling agent. At a preset ambient temperature, the various raw material components are mixed evenly according to a preset shear force to obtain a raw material mixture; The raw material mixture is ground at least three times using a three-roll mill to obtain an epoxy resin conductive paste.

2. The method for preparing low-shrinkage epoxy resin conductive paste according to claim 1, characterized in that, The average particle size of the silver powder is below 10.00µm.

3. The method for preparing low-shrinkage epoxy resin conductive paste according to claim 2, characterized in that, The silver powder contains small-particle-size flake silver powder.

4. The method for preparing low-shrinkage epoxy resin conductive paste according to claim 1, characterized in that, The curing agent is selected through the following steps: Construct an evaluation table for various cationic curing agents to assess their curing behavior, bond strength, thermal stability, and storage stability under the same or different heating conditions; Based on the application requirements of the epoxy resin conductive paste, the corresponding cationic curing agent is obtained from the curing agent evaluation table as the curing agent in the raw material components.

5. The method for preparing low-shrinkage epoxy resin conductive paste according to claim 4, characterized in that, The step of obtaining the corresponding cationic curing agent as the curing agent in the raw material component includes: If the epoxy resin conductive paste is used to bond materials with low heat resistance requirements, AE-100 cationic curing agent is used as the curing agent in the raw material components. If the epoxy resin conductive paste is used for bonding metal and plastic, AE-400 cationic curing agent is used as the curing agent in the raw material components; If the epoxy resin conductive paste is used for bonding in high-precision, confined spaces, AE-700 cationic curing agent is used as the curing agent in the raw material components.

6. A low-shrinkage epoxy resin conductive paste, characterized in that, It is prepared by means of a variety of raw material components; the variety of raw material components includes 80 wt% silver powder, 16 wt% alicyclic epoxy resin, 2 wt% diluent, 1.1 wt% curing agent, 0.3 wt% dispersant and 0.6 wt% coupling agent.

7. The low-shrinkage epoxy resin conductive paste according to claim 6, characterized in that, The average particle size of the silver powder is below 10.00µm.

8. The low-shrinkage epoxy resin conductive paste according to claim 7, characterized in that, The silver powder contains small-particle-size flake silver powder.

9. The low-shrinkage epoxy resin conductive paste according to claim 6, characterized in that, The curing agent is selected through the following steps: Construct an evaluation table for various cationic curing agents to assess their curing behavior, bond strength, thermal stability, and storage stability under the same or different heating conditions; Based on the application requirements of the epoxy resin conductive paste, the corresponding cationic curing agent is obtained from the curing agent evaluation table as the curing agent in the raw material components.

10. The low-shrinkage epoxy resin conductive paste according to claim 9, characterized in that, The step of obtaining the corresponding cationic curing agent as the curing agent in the raw material component includes: If the epoxy resin conductive paste is used to bond materials with low heat resistance requirements, AE-100 cationic curing agent is used as the curing agent in the raw material components. If the epoxy resin conductive paste is used for bonding metal and plastic, AE-400 cationic curing agent is used as the curing agent in the raw material components; If the epoxy resin conductive paste is used for bonding in high-precision, confined spaces, AE-700 cationic curing agent is used as the curing agent in the raw material components.

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