High-temperature-resistant high-insulation compounded epoxy pouring sealant, preparation method and application thereof

Abstract

This invention discloses a high-temperature resistant, high-insulation compounded epoxy potting compound, its preparation method, and its application. The compounded epoxy potting compound is prepared by compounding 4,4'-diaminodiphenyl sulfone (DDS) with diethyltoluene diamine (DETDA) with different reactivity and curing bisphenol A type epoxy resin E-51. A step-curing process is employed: the first stage initiates a preliminary crosslinking reaction; the second stage accelerates the ring-opening addition of amine and epoxy groups; the third stage allows for the full reaction of DDS to form a highly crosslinked network structure; and the fourth stage completes the curing reaction of the remaining epoxy groups. The compounded epoxy potting compound obtained by this invention exhibits good mechanical properties. Due to the synergistic optimization of DDS and DETDA, the processing temperature can be reduced from 105℃ to 64℃, while simultaneously exhibiting a high glass transition temperature (T0). g >200℃) and high volume resistivity (10 16 With excellent properties of Ω·cm, it is a high-temperature resistant and high-insulation potting compound.

Description

Technical Field

[0001] This application belongs to the field of epoxy resin potting compound technology, and particularly relates to a high-temperature resistant and high-insulation composite epoxy potting compound, its preparation method and application. Background Technology

[0002] As a "protective shell" for electronic components, potting compounds not only need to have good mechanical properties to isolate them from the external environment (such as moisture, dust and chemical corrosion), but also need to have good thermal stability and high electrical insulation properties to ensure the reliable operation of electronic components under high temperature and high pressure environments.

[0003] Epoxy resins are commonly used matrix materials in the electronic packaging field due to their excellent adhesion, mechanical properties, and processing flexibility. However, the final performance of epoxy potting compounds is highly dependent on the choice of curing agent and the cross-linked network structure formed. In existing high-performance potting systems, aromatic amine curing agents are commonly used:

[0004] (1) Aromatic amines with symmetrical structure (such as 4,4'-diaminodiphenyl sulfone, DDS): This type of curing agent can form a highly cross-linked rigid network with epoxy resin, giving the material an extremely high glass transition temperature (Tg) and excellent thermal stability. However, the disadvantages are high curing temperature, slow reaction rate, easy brittle fracture of the cured product, and high melt viscosity leading to poor processability.

[0005] (2) Steric hindered aromatic amines (such as diethyltoluene diamine, DETDA): can effectively reduce the curing temperature and process difficulty of the system, and the side groups of its molecular chain can effectively toughen the system. However, when DETDA is used alone, the thermal performance and modulus of the cured system are insufficient, which to some extent restricts its application in engineering.

[0006] To overcome the limitations of single-curing-agent systems in improving the performance of epoxy potting compounds, compound curing has become an important method for performance control. Therefore, developing a high-temperature resistant, high-insulation compound epoxy potting compound and its preparation method is a pressing technical problem in the field of electronic component packaging. Summary of the Invention

[0007] The purpose of this application is to provide a high-temperature resistant, high-insulation composite epoxy potting compound, its preparation method, and its application, in order to solve the above-mentioned technical problems.

[0008] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0009] This application provides a method for preparing a high-temperature resistant, high-insulation composite epoxy potting compound, comprising the following steps:

[0010] S1. Preparation of compounded epoxy resin adhesive: Place bisphenol A type epoxy resin E-51 in a 130°C oil bath, add 4,4'-diaminodiphenyl sulfone (DDS) curing agent and mechanically stir until completely dissolved; after cooling to 90°C, add diethyltoluenediamine (DETDA) curing agent, followed by nano alumina, defoamer, dispersant and leveling agent in sequence, and stir to form a homogeneous system;

[0011] For example, accurately weigh epoxy resin E-51 into a beaker, add the stoichiometric amount of DDS curing agent, heat it in a 130°C oil bath with mechanical stirring (300 rpm) for 15 minutes until the DDS is completely dissolved. Then, lower the temperature to 90°C, add the pre-defined molar ratio of DETDA curing agent according to the amount of DDS, followed by 3 wt.% nano-alumina, 1 wt.% defoamer, 1 wt.% dispersant, and 1 wt.% leveling agent. Continue stirring for 10 minutes to ensure that the two amine curing agents are fully dispersed in the resin and form a homogeneous system. Specific formulation quality examples are shown in Table 1.

[0012]

[0013] S2. Vacuum degassing treatment: The adhesive solution is treated at -0.065 MPa and 90°C for 12–15 min until no more bubbles escape.

[0014] For example, the epoxy resin solution is transferred to a vacuum degassing device and treated at -0.065 MPa and 90°C for 12–15 minutes until no more bubbles escape from the solution.

[0015] S3, Stepped Curing: A four-stage stepped curing process is adopted: First stage: Initiating preliminary crosslinking and eliminating reaction bubbles; Second stage: Accelerating the ring-opening addition of amine and epoxy groups to form a medium crosslinking density;

[0016] The third stage: allowing DDS to fully react and constructing a highly cross-linked network structure; the fourth stage: completing the curing of residual epoxy groups and improving thermal stability.

[0017] For example, the curing process. The degassed epoxy resin is poured into a pre-treated and dried PTFE mold, with the pouring speed controlled to avoid introducing secondary air bubbles. The mold is then moved into an oven for a stepped curing process. The first stage: 90℃ / 1h, promotes further diffusion of the curing agent in the resin, initiates the initial cross-linking reaction, and eliminates air bubbles generated in the initial reaction; the second stage: 150℃ / 2h, accelerates the ring-opening addition of amine and epoxy groups, forming a moderate cross-linking density; the third stage: 190℃ / 3h, achieves full reaction of DDS, constructing a highly cross-linked network structure; the fourth stage: 230℃ / 2h, completes the curing reaction of residual epoxy groups and promotes the improvement of the thermal stability of the epoxy resin system. The curing reaction process is as follows: Figure 1 As shown.

[0018] In some embodiments of this application, in step S1, the mass ratio of DDS to DETDA is between 6:4 and 9:1.

[0019] In some embodiments of this application, in step S1, the alumina nanoparticles are 10 nanometers to 100 nanometers in size and are added in a mass percentage of 2 wt.% to 5 wt.%.

[0020] In some embodiments of this application, in step S1, the amount of defoamer, dispersant and leveling agent added is 1 wt. of the total system mass.

[0021] In some embodiments of this application, the specific curing parameters in step S3 are as follows:

[0022] The first stage of curing temperature and time is 90±10℃ and 0.5-2 hours;

[0023] The second stage of curing temperature and time is 150±20℃ and 1-3 hours;

[0024] The third stage of curing temperature and time is 190±20℃ and 2-4 hours;

[0025] The fourth stage of curing involves a temperature and time of 230±30℃ and 1-3 hours.

[0026] Secondly, this application also provides a high-temperature resistant, high-insulation composite epoxy potting compound prepared by the method described above.

[0027] In some embodiments of this application, the glass transition temperature T of the potting compound is... g At temperatures above 200°C, the volume resistivity is not less than 10. 16 Ω·cm.

[0028] In some embodiments of this application, the potting compound has a nanoscale microphase separation structure and its initial decomposition temperature Td5% > 400°C.

[0029] Thirdly, this application also provides the wide application of the high-temperature resistant and high-insulation compounded epoxy potting compound described above in the field of electronic component potting.

[0030] Compared with the prior art, the beneficial effects of the embodiments of this application are:

[0031] This application provides a high-temperature resistant, high-insulation composite epoxy potting compound, its preparation method, and its application. A composite epoxy potting compound is prepared by compounding 4,4'-diaminodiphenyl sulfone (DDS) with diethyltoluene diamine (DETDA) of different reactivity and curing bisphenol A type epoxy resin E-51. A step-curing process is performed simultaneously: the first stage initiates a preliminary crosslinking reaction; the second stage accelerates the ring-opening addition of amine and epoxy groups; the third stage allows for the full reaction of DDS to form a highly crosslinked network structure; and the fourth stage completes the curing reaction of the remaining epoxy groups. The composite epoxy potting compound obtained by this invention exhibits good mechanical properties. Due to the synergistic optimization of DDS and DETDA, the processing temperature is reduced from 105℃ to 64℃, while simultaneously exhibiting a high glass transition temperature (Tg>200℃) and high volume resistivity (10 Ω·cm). 16 With excellent properties of Ω·cm, it is a high-temperature resistant and high-insulation potting compound.

[0032] For example, when DDS / DETDA curing agents are compounded, and the DETDA content is not less than 20%, the processing temperature can be significantly reduced from 105℃ to below 65℃, and the activation energy of the system reaction can be effectively reduced, thus effectively lowering the curing temperature of the potting compound and reducing the curing time. AFM confirmed that this compounded system forms a nanoscale microphase separation structure, which allows the system to maintain a high glass transition temperature (>200℃) and excellent insulation properties (volume resistivity >10). 16 While possessing excellent thermal stability (initial decomposition temperature > 400℃) and good mechanical properties, ES8A2 was determined to be the optimal formulation, achieving the best comprehensive balance between processability, mechanical properties and temperature resistance, thus successfully developing a high-temperature resistant and high-insulation compound epoxy potting compound. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is the curing reaction formula for a high-temperature resistant, high-insulation compound epoxy potting compound.

[0035] Figure 2 The viscosity-temperature relationship for compounded epoxy potting compounds.

[0036] Figure 3 The AFM diagram for the compounded epoxy potting compound, where (a) ES 10 A0's 2D phase diagram, (b) ES 10 (c) 3D height map of A0, (d) 2D phase map of ES8A2, (e) 3D height map of ES8A2.

[0037] Figure 4 Thermogravimetric analysis of compounded epoxy potting compounds.

[0038] Figure 5 The tensile strength and tensile modulus of the compounded epoxy potting compound.

[0039] Figure 6 Stress-strain curves for compounded epoxy potting compounds. Detailed Implementation

[0040] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0041] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0043] To address the shortcomings of the prior art as pointed out in the background, this application provides a high-temperature resistant and high-insulation compounded epoxy potting compound, its preparation method, and its application. The compounding of DDS and DETDA can theoretically achieve complementary performance, but the differences in their reactivity and structure will result in an extremely complex curing process and micro-network structure.

[0044] The activation energy characteristics of this system can be attributed to the high activation energy imparted by the sulfone group in DDS: its electron-withdrawing effect inhibits the reaction by reducing the electron cloud density of the benzene ring; simultaneously, its diphenyl sulfone resonance structure effectively dissipates energy, thereby stabilizing the crosslinked network. As a sterically hindered aromatic amine, DETDA's sterically hindered groups can sometimes alter the electron cloud density of the reaction center through hyperconjugation or inductive effects. The electron-donating effect of the alkyl group in DETDA increases the electron cloud density of the nitrogen atom, thereby enhancing its nucleophilicity and reactivity. Therefore, increasing the DETDA content leads to a corresponding decrease in the activation energy.

[0045] Theoretically, the DDS / DETDA blend is not a simple physical mixture, but rather produces a positive synergistic effect at the level of chemical reaction kinetics. However, there are no reports on the use of DDS / DETDA blends to achieve synergistic optimization and fine-tuning the curing process of bisphenol A type epoxy resin E-51 to prepare high-temperature resistant, high-insulation potting compounds.

[0046] This invention uses epoxy resin E-51 as the base resin, blends DDS and DETDA in different proportions, and uses nano-alumina as a thermally conductive filler to study the effects of epoxy resin system processing performance, curing behavior, thermal properties, mechanical properties and electrical properties. It explores the synergistic optimization of the microstructure formed by the blended curing agent on the comprehensive performance of epoxy potting compound, and obtains a high-temperature resistant and high-insulation potting compound formulation and curing process.

[0047] This invention is achieved as follows: the formulation includes E-51 resin, DDS, DETDA, nano-alumina (20 nm), and defoamer (BYK-A530), dispersant (BYK-111), and leveling agent (BYK-110). Using a two-component aromatic amine as a compound curing agent, and adjusting the molar ratio of DDS to DETDA, epoxy potting compounds with different formulations were prepared.

[0048] To illustrate the technical solution described in this application, specific embodiments are provided below. Example 1

[0049] Step 1: Accurately weigh 100g of epoxy resin E-51 into a beaker, add 28.8g of DDS curing agent, heat in a 130℃ oil bath with mechanical stirring (300 rpm) for 15 min until the DDS is completely dissolved. Then lower the temperature to 90℃, add 2.3g of DETDA curing agent, followed by 3g of nano alumina, 1g of defoamer, 1g of dispersant, and 1g of leveling agent, and continue stirring for 10 min.

[0050] Step 2: Transfer the above epoxy resin solution to a vacuum degassing device and treat it at -0.065 MPa and 90℃ for 12–15 min until no visible bubbles escape from the inside of the solution.

[0051] Step 3: Pour the degassed epoxy resin solution into the pre-treated and dried PTFE mold and perform a stepped curing process. First stage: 90℃ / 1 h to initiate the initial crosslinking reaction; Second stage: 150℃ / 2 h to accelerate the ring-opening addition of amine and epoxy groups; Third stage: 190℃ / 3 h to achieve complete DDS reaction; Fourth stage: 230℃ / 2 h to complete the curing reaction of the residual epoxy groups. The resulting epoxy potting compound T... d5% The temperature is 398.6℃, and the volume resistivity is 1.09×10⁻⁶. 16 Ω·cm, tensile strength is 45.77MPa. Example 2

[0052] Step 1: Accurately weigh 100g of epoxy resin E-51 into a beaker, add 25.6g of DDS curing agent, heat in a 130℃ oil bath with mechanical stirring (300 rpm) for 12 min until the DDS is completely dissolved. Then lower the temperature to 95℃, add 4.6g of DETDA curing agent, followed by 3g of nano alumina, 1g of defoamer, 1g of dispersant, and 1g of leveling agent, and continue stirring for 10 min.

[0053] Step 2: Same as step 2 in Example 1.

[0054] Step 3: Pour the degassed epoxy resin solution into the pre-treated and dried PTFE mold and perform a stepped curing process. First stage: 95℃ / 1 h to initiate the initial crosslinking reaction; Second stage: 150℃ / 2.5 h to accelerate the ring-opening addition of amine and epoxy groups; Third stage: 190℃ / 3 h to achieve complete DDS reaction; Fourth stage: 220℃ / 2 h to complete the curing reaction of residual epoxy groups. The resulting epoxy potting compound T... d5% Its temperature is 405.7℃, and its volume resistivity is 1.90×10⁻⁶. 16 Ω·cm, tensile strength is 54.43MPa. Example 3

[0055] Step 1: Accurately weigh 100g of epoxy resin E-51 into a beaker, add 22.4g of DDS curing agent, heat in a 130℃ oil bath with mechanical stirring (300 rpm) for 12 minutes until the DDS is completely dissolved. Then lower the temperature to 95℃, add 6.9g of DETDA curing agent, followed by 3g of nano alumina, 0.8g of defoamer, 1g of dispersant, and 1.2g of leveling agent, and continue stirring for 10 minutes.

[0056] Step 2: Same as step 2 in Example 1.

[0057] Step 3: Pour the degassed epoxy resin solution into the pre-treated and dried PTFE mold and perform a stepped curing process. First stage: 90℃ / 1 h to initiate the initial crosslinking reaction; Second stage: 150℃ / 2.5 h to accelerate the ring-opening addition of amine and epoxy groups; Third stage: 195℃ / 3 h to achieve complete reaction of DDS; Fourth stage: 220℃ / 2.5 h to complete the curing reaction of residual epoxy groups. The resulting epoxy potting compound T... d5% The temperature is 402.3℃, and the volume resistivity is 1.48×10⁻⁶. 16 Ω·cm, tensile strength is 54.27MPa. Example 4

[0058] Step 1: Accurately weigh 100g of epoxy resin E-51 into a beaker, add 19.2g of DDS curing agent, heat in a 130℃ oil bath with mechanical stirring (300 rpm) for 12 min until the DDS is completely dissolved. Then lower the temperature to 95℃, add 9.2g of DETDA curing agent, followed by 3g of nano alumina, 1g of defoamer, 1.2g of dispersant, and 1g of leveling agent, and continue stirring for 10 min.

[0059] Step 2: Same as step 2 in Example 1.

[0060] Step 3: Pour the degassed epoxy resin solution into the pre-treated and dried PTFE mold and perform a stepped curing process. First stage: 95℃ / 1 h to initiate the initial crosslinking reaction; Second stage: 155℃ / 2.5 h to accelerate the ring-opening addition of amine and epoxy groups; Third stage: 195℃ / 3 h to achieve complete DDS reaction; Fourth stage: 220℃ / 2 h to complete the curing reaction of residual epoxy groups. The resulting epoxy potting compound T... d5% The temperature is 388.5℃, and the volume resistivity is 1.06×10⁻⁶. 16 Ω·cm, tensile strength is 41.38MPa.

[0061] Performance Evaluation

[0062] (1) Viscosity-temperature relationship of compounded epoxy potting compound

[0063] Viscosity reflects the difficulty of applying potting compounds and is a primary performance consideration. The viscosity of a compound system changes with temperature, such as... Figure 2 As shown in the figure, the viscosity of all compounded epoxy potting compounds decreases with increasing temperature, consistent with the general laws of polymer rheology. With increasing DETDA dosage, the viscosity of the system at the same temperature shows a regular decrease. For example, at 60℃, the viscosities of the three potting compounds ES8A2, ES7A3, and ES6A4 are all between 2000 and 4000 mPa·s, while the viscosities of the other two groups are significantly higher, resulting in poor processing performance at around 60℃. This demonstrates that the introduction of DETDA, especially when its content reaches a certain level, can significantly improve the processing performance of epoxy potting compounds at moderate temperatures. The improvement in processing performance is mainly attributed to two aspects: firstly, DETDA, as a low-viscosity liquid, can act as an effective diluent, significantly reducing the overall viscosity of the system; secondly, when the proportion of DETDA in the formulation is increased to 20% or more, it can effectively plasticize the crystalline solid DDS, transforming the entire curing agent system from a "solid-liquid suspension" to a "liquid-liquid solution."

[0064] (2) Correlation between microstructure and performance of compounded epoxy potting compound

[0065] The synergistic effect of the DDS / DETDA compound system is related to its microstructure. AFM was used to characterize the microphase structure of typical formulation samples in multiple dimensions. Figure 3 For ES 10 2D phase diagram and 3D height diagram of A0 and ES8A2.

[0066] In ES 10 In the 2D phase diagram of the A0 system ( Figure 3 (a) shows a clearly uniform dark field, with a few bright spots representing aluminum oxide. (3D height map) Figure 3 (b) is also consistent with the phase diagram conclusion. This result shows that the viscoelasticity of the sample is highly consistent within the scanning region, with no nanoscale modulus fluctuations, confirming that it forms a homogeneous network structure without microphase separation.

[0067] 2D phase diagram of the ES8A2 system ( Figure 3 (c) The image exhibits a clear contrast between light and dark areas, a typical characteristic of microphase separation morphology. The dark and bright areas intertwine and intertwine, forming a bicontinuous structure. Specifically, the bright areas are high-modulus DDS rigid enrichment regions, while the dark areas are low-modulus DETDA flexible enrichment regions, such as... Figure 3As shown in (d), the high-modulus bright region and the low-modulus dark region exhibit varying heights. This structure is formed primarily due to two reasons: First, DDS and DETDA differ in molecular structure and polarity, resulting in limited compatibility in epoxy resins and a tendency for thermodynamic phase separation. Second, their reactivity differs; DETDA is more reactive and readily reacts with some epoxy groups in the initial stages of the reaction, while DDS reacts during the high-temperature curing stage to form a highly cross-linked network. This difference in reaction gradually strengthens phase separation during curing, ultimately forming the microphase-separated structure shown in the figure.

[0068] In the ES8A2 system, microphase separation creates suitable phase region sizes, and the interfacial bonding between the two phases optimizes its performance. In this structure, the DDS acts as a supporting framework maintaining rigidity and heat resistance, while an appropriate amount of DETDA is effectively interwoven within the DDS network, forming a bicontinuous interpenetrating network. This type of rigid-flexible structure maintains high T... g While possessing high modulus, it can effectively dissipate energy through a flexible phase, preventing or slowing down material fracture and significantly improving the fracture toughness of the material.

[0069] (3) Thermogravimetric analysis of compounded epoxy potting compound

[0070] Thermogravimetric analysis (TGA) is a key method for evaluating the thermal stability of materials. Figure 4 The TGA and DTG curves of the compounded epoxy potting compound system are shown, and the relevant thermogravimetric data obtained based on these curves are listed in Table 2.

[0071]

[0072] Figure 4 It can be seen that all compounded epoxy potting compounds undergo one-step decomposition, and T d5% T d10% T max All temperatures were above 400℃. The addition of DETDA did not significantly affect the thermal decomposition temperature of the original system. This is mainly because although DETDA contains flexible groups, it is essentially still an aromatic ring. At the same time, as shown in the AFM results, the system formed a nanoscale microphase separation structure. The highly cross-linked and thermally stable rigid phase formed by DDS constitutes a continuous framework, which encapsulates the thermally less stable DETDA phase. This structure slows down the diffusion of small molecule volatiles during the thermal decomposition of the DETDA phase, acting as a nanoscale physical barrier. Furthermore, its phase interface may also hinder heat transfer.

[0073] (4) Mechanical properties of compounded epoxy potting compound

[0074] Figure 5 and Figure 6 To assess the overall tensile properties of the compounded epoxy potting compound system. Figure 5It is evident that all systems possess high modulus and strength, but the peak values ​​appear at ES8A2 and ES7A3, indicating that their changes are not monotonically dependent on composition, but rather exhibit a synergistic optimization effect. In the ES8A2 and ES7A3 systems, the strong interfacial interactions of the microphase-separated structures can induce and terminate microcracks, thereby activating multiple energy-dissipating processes, increasing fracture elongation and fracture energy, ultimately manifesting as an increase in the area under the stress-strain curve and enhanced toughness. Figure 6 As shown.

[0075] The ES8A2 and ES7A3 systems exhibit a balance of high strength, high modulus, and high toughness, demonstrating the optimization of the mechanical properties of potting compounds by the microphase separation structure.

[0076] (5) Electrical insulation properties of the compounded epoxy potting compound system

[0077] As a "protective shell" for electronic devices, excellent electrical insulation performance is one of the most fundamental functional requirements of potting compounds. Volume resistivity characterizes a material's ability to resist conductivity and is a key indicator for evaluating insulation performance. Its formula (1) is as follows:

[0078] (1)

[0079] In the formula: —Volume resistivity, Ω·cm; —Volume resistivity, Ω; —Electrode area, cm 2 ; —Sample thickness, cm.

[0080] Table 3 shows the volume resistivity of the compound epoxy potting compound system, which exhibits excellent insulation properties, with all volume resistivity below 10. 16 The system achieves an Ω·cm level, meeting the insulation requirements of high-performance epoxy potting compounds. The excellent insulation properties are mainly due to three factors: First, the E-51 resin, DDS, and DETDA curing agents, and the resulting three-dimensional cross-linked network are intrinsically insulating, resulting in very few mobile electrons and forming the basis for its high resistivity. Second, the microphase separation structure, with its strong interfacial bonding and interpenetrating network, makes the original structure more compact, effectively suppressing the migration of ions and other impurities, preventing the formation of through-conductive pathways. Furthermore, the aromatic rings in the DDS and DETDA molecules contain large π bonds, which effectively bind electrons and inhibit electron flow, further enhancing the insulation properties of the potting compound. Based on these properties of the compounded epoxy potting compound, ES8A2 was determined to be the optimal formulation, achieving the best overall balance.

[0081]

[0082] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for preparing a high-temperature-resistant and high-insulation compounded epoxy potting adhesive, characterized in that, Includes the following steps: S1. Preparation of compounded epoxy resin adhesive: Place bisphenol A type epoxy resin E-51 in a 130°C oil bath, add 4,4'-diaminodiphenyl sulfone (DDS) curing agent and mechanically stir until completely dissolved; after cooling to 90°C, add diethyltoluenediamine (DETDA) curing agent, followed by nano alumina, defoamer, dispersant and leveling agent in sequence, and stir to form a homogeneous system; S2. Vacuum degassing treatment: The adhesive solution is treated at -0.065 MPa and 90°C for 12-15 minutes until no more bubbles escape. S3, Stepped Curing: A four-stage stepped curing process is adopted: First stage: Initiating preliminary crosslinking and eliminating reaction bubbles; Second stage: Accelerating the ring-opening addition of amine and epoxy groups to form a medium crosslinking density; The third stage: allowing DDS to fully react and constructing a highly cross-linked network structure; the fourth stage: completing the curing of residual epoxy groups and improving thermal stability. In step S1, the mass ratio of DDS to DETDA is between 5.57:1 and 3.25:1; In step S1, the alumina nanoparticles are 10 to 100 nanometers in size, and their mass percentage is 2 wt.% to 5 wt.%. The specific curing parameters in step S3 are as follows: The first stage of curing is at 90±10℃ for 0.5-2 hours; the second stage is at 150±20℃ for 1-3 hours; the third stage is at 190±20℃ for 2-4 hours; and the fourth stage is at 230±30℃ for 1-3 hours.

2. The method of claim 1, wherein: In step S1, the amount of defoamer, dispersant, and leveling agent added is 1 wt.% of the total system mass.

3. A high-temperature resistant, high-insulation composite epoxy potting compound prepared by the method of claim 1 or 2.

4. The potting compound according to claim 3, characterized in that: The glass transition temperature Tg of the potting adhesive is 80-120°C g >200°C, the volume resistivity is not less than 10 16 Ω·cm.

5. The potting compound according to claim 4, characterized in that: The potting adhesive has a nano-scale microphase separation structure, and its initial decomposition temperature T d5% >400°C.

6. The application of the high-temperature resistant and high-insulation compound epoxy potting compound according to claim 3 in the field of electronic component potting.

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