Anti-cracking, high-temperature-resistant epoxy potting adhesive, preparation method and application thereof

Abstract

The application provides an anti-cracking and high-temperature-resistant epoxy pouring sealant as well as a preparation method and application thereof.The epoxy pouring sealant comprises components A and B according to mass fraction;the component A comprises 12-18% of epoxy resin, 25-45% of a first filler, 0.1-0.5% of a coupling agent and 0.1-0.5% of a first wet dispersing agent;the component B comprises 15-25% of a curing agent, 25-35% of a second filler, 0.1-0.6% of a catalyst, 0.1-0.5% of a second wet dispersing agent and 0.05-0.2% of carbon black;wherein the epoxy resin is composed of a difunctional alicyclic epoxy resin and a multifunctional alicyclic epoxy resin containing a flexible chain segment.The difunctional alicyclic epoxy resin and the multifunctional alicyclic epoxy resin containing a flexible chain segment synergistically act, the multifunctional alicyclic epoxy resin containing a flexible chain segment optimizes the problem that the crosslinking network rigidity of the difunctional alicyclic epoxy resin is large and the curing shrinkage is high, so that the epoxy pouring sealant has excellent high-temperature resistance and improved anti-cracking performance.

Description

Technical Field

[0001] This invention relates to the field of electronic component packaging composition technology, specifically to a crack-resistant, high-temperature resistant epoxy potting compound, its preparation method, and its application. Background Technology

[0002] With the rapid development of new energy vehicles and intelligent in-vehicle electronic equipment, higher requirements have been placed on the functionality and safety of in-vehicle electronic devices. Rectifier diodes, IGBT power modules, and other semiconductor devices, as core components of generator rectifiers, voltage converters, and motor controllers, undertake important functions such as AC to DC conversion, battery charging, high-to-low voltage conversion in circuits, and protection of power switching devices. Their operational stability directly determines the safety and lifespan of the entire vehicle's electrical equipment and even the vehicle itself. Compared to traditional consumer electronic components, automotive-grade power devices operate in more complex and demanding environments, facing long-term continuous high-temperature operation, alternating high and low temperature shocks, mechanical vibration, and corrosion from various substances in the environment. Therefore, higher technical requirements are placed on the continuous high-temperature resistance, anti-aging properties, insulation performance, and stability of the supporting encapsulation and potting materials.

[0003] Currently, most epoxy potting compounds on the market use bisphenol A type epoxy resin or a combination of multifunctional epoxy resins, prepared with anhydride or amine curing agents. While offering balanced basic performance and high cost-effectiveness, they exhibit significant technical shortcomings in high-end automotive devices such as automotive-grade high-power rectifier diodes. Firstly, conventional epoxy potting compounds suffer from high curing shrinkage during the curing process. During the cross-linking reaction stage, the tightly packed molecular chains easily lead to significant volume shrinkage, resulting in internal stress within the device. For miniaturized and precision automotive rectifier diodes, excessive curing stress can easily cause defects such as colloid cracking, delamination between the colloid and the leads or housing frame leading to moisture ingress, and chip breakage. Furthermore, under thermal cycling conditions, the high-shrinkage potting compound has poor thermal expansion matching with the semiconductor substrate; the shear stress generated by the difference in expansion and contraction continuously damages the encapsulation interface, leading to device failure. Secondly, the glass transition temperature (Tg) of existing conventional epoxy potting compounds is generally below 220℃, making it difficult to meet the ultra-high temperature requirements of automotive-grade electronic components in specific automotive equipment. High-power rectifier diodes can reach instantaneous junction temperatures exceeding 200°C under full load, while SiC-based rectifier devices can exceed 220°C in short-term peak junction temperatures. Low-Tg potting compounds are prone to high-temperature creep when operating under critical temperature conditions for extended periods. Repeated softening and hardening during thermal cycling accelerates the initiation and propagation of internal microcracks, significantly shortening device lifespan. Currently, there are no epoxy potting compounds on the market that simultaneously meet the requirements of a Tg higher than 220°C and also exhibit low shrinkage and crack resistance.

[0004] To address the aforementioned issues, it is necessary to develop a novel automotive-grade epoxy potting compound that is crack-resistant and high-temperature resistant, in order to meet the high-performance material requirements of automotive electronic devices. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a crack-resistant, high-temperature-resistant epoxy potting compound, its preparation method, and its application, thus solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, a crack-resistant and high-temperature resistant epoxy potting compound is provided, comprising component A and component B by mass fraction, wherein the total mass of component A and component B is 100%. Component A comprises 12-18% epoxy resin, 25-45% first filler, 0.1-0.5% coupling agent and 0.1-0.5% first wetting and dispersing agent; Component B comprises 15-25% curing agent, 25-35% second filler, 0.1-0.6% catalyst, 0.1-0.5% second wetting and dispersing agent, and 0.05-0.2% carbon black; The epoxy resin is composed of a difunctional alicyclic epoxy resin and a multifunctional alicyclic epoxy resin containing flexible segments.

[0007] The epoxy resin of this invention is composed of a difunctional alicyclic epoxy resin and a polyfunctional alicyclic epoxy resin containing flexible segments. The difunctional alicyclic epoxy resin has a high glass transition temperature, which improves its high temperature resistance and anti-aging properties. Combined with the polyfunctional alicyclic epoxy resin containing flexible segments, the polycyclic epoxy functional groups can further increase the glass transition temperature. Ester bonds, ether bonds, and long alicyclic segments can reduce the rigidity of the crosslinking network of the epoxy potting compound and reduce the curing shrinkage rate, giving the epoxy potting compound excellent crack resistance and excellent high temperature resistance.

[0008] This invention limits the amount of polyfunctional alicyclic epoxy resin containing flexible segments in the epoxy resin. Too little amount results in insufficient crack resistance of the epoxy potting compound, while too much amount leads to excessive viscosity and poor potting workability. More preferably, the mass of the polyfunctional alicyclic epoxy resin containing flexible segments accounts for 10-50% of the total epoxy resin.

[0009] Preferably, the difunctional alicyclic epoxy resin is selected from at least one of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester and 3,4,3',4'-diepoxydicyclohexane; The multifunctional alicyclic epoxy resin containing flexible segments is selected from at least one of structural formula (I) and structural formula (II); .

[0010] Preferably, the curing agent is selected from at least one of methylhexahydrophthalic anhydride (MHHPA) and methylnadic anhydride (NA).

[0011] Preferably, the catalyst is selected from at least one of imidazole catalysts and organozinc catalysts.

[0012] Preferably, the imidazole catalyst is selected from at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, and 2,4-diamino-6-[2-(2-methyl-1-imidazole)ethyl]-1,3,5-triazine; The organozinc catalyst is selected from zinc isooctanoate and zinc acetylacetonate.

[0013] The catalyst provided by this invention provides imidazole catalysts, which can provide high glass transition temperatures but have high curing shrinkage rates, and organozinc catalysts, which can significantly reduce curing shrinkage rates but lower glass transition temperatures. To balance shrinkage resistance and high-temperature resistance, the catalyst is further preferably composed of imidazole catalysts and organozinc catalysts, with a mass ratio of imidazole catalyst to organozinc catalyst of 1 to 5:1. Through the synergistic effect of imidazole catalysts and organozinc catalysts, the epoxy potting compound can maintain both a high glass transition temperature and a low shrinkage rate, thereby achieving crack resistance and high-temperature resistance.

[0014] Preferably, the coupling agent is selected from at least one of γ-glycidyl ether propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and phenylaminopropyltrimethoxysilane; The first filler and the second filler are independently selected from at least one of angular silica and spherical silica; The first wetting and dispersing agent and the second wetting and dispersing agent are independently selected from at least one of DISPERBYK-118, DISPERBYK-102, and DISPERBYK-2152.

[0015] According to a second aspect of the present invention, a method for preparing a crack-resistant and high-temperature resistant epoxy potting compound is provided, comprising the following steps: Preparation of Component A: Epoxy resin, coupling agent and first wetting and dispersing agent are premixed, then the first filler is added, and the mixture is stirred at 40~50℃ and degassed under vacuum to obtain Component A; Preparation of component B: The curing agent, the second wetting and dispersing agent, the catalyst and carbon black are premixed, and then the second filler is added. The mixture is stirred at 40~50℃ and degassed under vacuum to obtain component B.

[0016] According to a third aspect of the present invention, an epoxy potting compound or an epoxy potting compound prepared according to the above preparation method is provided as an encapsulating adhesive for use in automotive electronic components.

[0017] This invention provides a crack-resistant, high-temperature-resistant epoxy potting compound, its preparation method, and its application. It possesses the following beneficial effects: (1) The present solution provides a crack-resistant and high-temperature resistant epoxy potting compound. Through the synergistic effect of difunctional alicyclic epoxy resin and multifunctional alicyclic epoxy resin containing flexible segments, the multifunctional alicyclic epoxy resin containing flexible segments optimizes the problem of high rigidity and high curing shrinkage of the crosslinking network of difunctional alicyclic epoxy resin, so that the epoxy potting compound can improve crack resistance while having excellent high temperature resistance.

[0018] (2) The present solution provides a crack-resistant and high-temperature resistant epoxy potting compound. The epoxy resin is selected from difunctional alicyclic epoxy resin and polyfunctional alicyclic epoxy resin containing flexible segments, so that the epoxy potting compound has a high glass transition temperature and crack resistance, while ensuring the low viscosity of the epoxy potting compound so that it has excellent potting workability.

[0019] (3) The present solution provides a crack-resistant and high-temperature resistant epoxy potting compound. The catalyst is selected from a mixture of imidazole catalyst and organozinc catalyst. The imidazole catalyst can ensure a high glass transition temperature but has a high curing shrinkage rate. The organozinc catalyst can significantly reduce the curing shrinkage rate but reduce the glass transition temperature, thereby further improving the crack resistance and increasing the glass transition temperature. Attached Figure Description

[0020] Figure 1 Fourier transform infrared spectrum of a multifunctional alicyclic epoxy resin containing flexible segments according to structural formula (I) of the present invention. Figure 2The images show the epoxy potting compounds prepared in Examples 1-12 and Comparative Examples 1-4 of this invention after being stored at 225°C for 72 hours. In the images, A represents the epoxy potting compound of Example 1, B represents the epoxy potting compound of Example 2, C represents the epoxy potting compound of Example 3, D represents the epoxy potting compound of Example 4, E represents the epoxy potting compound of Example 5, F represents the epoxy potting compound of Example 6, G represents the epoxy potting compound of Example 7, H represents the epoxy potting compound of Example 8, I represents the epoxy potting compound of Example 9, J represents the epoxy potting compound of Example 10, K represents the epoxy potting compound of Example 11, L represents the epoxy potting compound of Example 12, M represents the epoxy potting compound of Comparative Example 1, N represents the epoxy potting compound of Comparative Example 2, O represents the epoxy potting compound of Comparative Example 3, and P represents the epoxy potting compound of Comparative Example 4. Detailed Implementation

[0021] To better illustrate the content of this invention, the following description is provided in conjunction with specific embodiments.

[0022] All raw materials used in this invention were purchased from the market, and their specific sources are as follows: Epoxy resin 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester TTA21P, manufacturer: Jiangsu Taiter New Material Technology Co., Ltd. Epoxy resin 3,4,3',4'-diepoxydicyclohexane TTA800, manufacturer: Jiangsu Taiter New Material Technology Co., Ltd. Epoxy Resin (II) Tetrafunctional Alicyclic Epoxy Resin EPOLEAD, Manufacturer: Daicel Co., Ltd. Catalyst imidazole adduct PN-40, manufacturer: Ajinomoto Fine Chemicals Co., Ltd., Japan; Catalyst Zinc Isooctanoate LK-4, Manufacturer: Shandong Lanyue New Material Technology Co., Ltd. Catalyst: Zinc acetylacetonate; Manufacturer: Nantong Huachunte Biotechnology Co., Ltd. Curing agent: Methylhexahydrophthalic anhydride; Manufacturer: Puyang Huicheng Electronic Materials Co., Ltd. Curing agent: methyl nadic anhydride; Manufacturer: Puyang Huicheng Electronic Materials Co., Ltd. Filler: Silicon dioxide RST-H2, Manufacturer: Lianyungang Lisite Electronic Materials Co., Ltd. Coupling agent CG-560, manufacturer: Jiangxi Chenguang New Materials Co., Ltd.; Wetting and dispersing agent DISPERBYK-102, manufacturer: BYK Additives (Shanghai) Co., Ltd. Carbon black N700, manufacturer: Suzhou Baohua Carbon Black Co., Ltd.; Methylcyclohexane; Shandong Xuchen Chemical Technology Co., Ltd.; p-Toluenesulfonic acid: Shanghai Ebi Chemical Reagent Co., Ltd.; Dicyclopentadiene, Manufacturer: Sinopec Shanghai Petrochemical Co., Ltd. Nadic anhydride, manufacturer: Puyang Huicheng Electronic Materials Co., Ltd.; tert-butyl hydrogen peroxide solution TBHP-70W, manufacturer: Jiangsu Qiangsheng Functional Chemical Co., Ltd. Sodium carbonate, manufacturer: Shandong Haihua Co., Ltd.

[0023] The synthesis process of the multifunctional alicyclic epoxy resin containing flexible segments according to structural formula (I) of the present invention is as follows:

[0024] The specific preparation method is as follows: a. A 500 mL flask was equipped with a condenser and a mechanical stirrer. 50 mL of methylcyclohexane solvent, 1.7 g of p-toluenesulfonic acid were added sequentially with stirring to dissolve, followed by 31 g of ethylene glycol. 66.1 g of dicyclopentadiene was then added dropwise at room temperature. The mixture was then heated to 85 °C and refluxed, with stirring for 4 h.

[0025] b. Add 41g of Nadic anhydride, reflux at 85℃, and stir for 4 hours.

[0026] c. Stop stirring and place in an ice bath. Add 64g of tert-butyl hydrogen peroxide solution dropwise and stir the reaction for 10h.

[0027] d. The reaction mixture was repeatedly washed with 5% sodium carbonate solution and deionized water until neutral, then the organic phase was washed five times with 100 ml of methylcyclohexane solvent. Finally, the solvent and water were removed by vacuum distillation, yielding 97.7 g of a pale yellow liquid product (theoretically 145.5 g), with a yield of 67.1%. The prepared product was analyzed by Fourier transform infrared spectroscopy as follows: Figure 1As shown, the FT-IR characteristic peaks are: 2933 (CH stretching vibration of saturated alicyclic rings), 1722 cm⁻¹ (strong absorption peak of C=O in ester carbonyl group), 1434 (in-plane bending vibration of methylene-CH₂- group), 1261 (CO stretching vibration of ester bond), 1180 (COC stretching vibration of aliphatic ether), 1007 (cage-like structure of polycyclic and five- or six-membered alicyclic rings), 912 (characteristic fingerprint peak of three-membered epoxy ring), and 777 cm⁻¹ (out-of-plane bending vibration of C-C bonds in the saturated dicyclopentadiene fused ring skeleton). Therefore, the polyfunctional alicyclic epoxy resin containing flexible segments in structural formula (I) contains three epoxy functional groups, providing a high crosslinking density. Furthermore, the epoxy groups are connected to the norbornene bridging ring and the five- or six-membered fused rings, thus exhibiting a high glass transition temperature and high-temperature resistance. Simultaneously, structural formula (I) contains ester and ether bonds, providing high toughness and low curing shrinkage, which can effectively improve the crack resistance of the cured product.

[0028] The epoxy resins of structural formulas (III) and (IV) in this application are flexible alicyclic epoxy resins disclosed in Chinese Patent CN118480015A, wherein the epoxy resin of structural formula (III) is: ; The epoxy resin of structural formula (IV) is:

[0029] The following detailed description, in conjunction with specific embodiments, illustrates a crack-resistant, high-temperature-resistant epoxy potting compound, its preparation method, and its applications.

[0030] Example 1 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 30.1% filler of type RST-H2, 14.1% epoxy resin of type TTA21P, 3.0% epoxy resin of structural formula (I), 0.2% coupling agent of type CG-560, and 0.2% wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.9% filler of type RST-H2, 21.85% curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% catalyst of type PN-40, 0.1% catalyst of zinc acetylacetonate, 0.2% wetting and dispersing agent of type DISPERBYK-102, and 0.05% carbon black of type N700; The specific preparation method is as follows: Preparation of component A: TTA21P, epoxy resin with structural formula (Ⅰ), coupling agent with model number CG-560 and wetting and dispersing agent with model number DISPERBYK-102 were premixed, and then filler with model number RST-H2 was added. The mixture was stirred at 45°C and degassed under vacuum to obtain component A. Preparation of Component B: Methylhexahydrophthalic anhydride (MHHPA), wetting and dispersing agent DISPERBYK-102, catalyst PN-40, zinc acetylacetonate, and carbon black N700 were premixed, and then filler RST-H2 was added. The mixture was stirred at 45°C and degassed under vacuum to obtain Component B.

[0031] Example 2 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 30.1% of filler of type RST-H2, 11.1% of epoxy resin of type TTA21P, 6.0% of epoxy resin of structural formula (I), 0.2% of coupling agent of type CG-560, and 0.2% of wetting and dispersing agent of type DISPERBYK-102. Component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% of catalyst of type PN-40, 0.1% of catalyst of zinc acetylacetonate, 0.2% of wetting and dispersing agent of type DISPERBYK-102, and 0.05% of carbon black of type N700.

[0032] Example 3 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 30.1% of filler of type RST-H2, 8.1% of epoxy resin of type TTA21P, 9.0% of epoxy resin of structural formula (I), 0.2% of coupling agent of type CG-560, and 0.2% of wetting and dispersing agent of type DISPERBYK-102. Component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% of catalyst of type PN-40, 0.1% of catalyst of zinc acetylacetonate, 0.2% of wetting and dispersing agent of type DISPERBYK-102, and 0.05% of carbon black of type N700.

[0033] Example 4 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 30.1% filler of type RST-H2, 14.1% epoxy resin of type TTA21P, 3.0% epoxy resin of structural formula (II), 0.2% coupling agent of type CG-560, and 0.2% wetting and dispersing agent of type DISPERBYK-102. Component B comprises 29.9% filler of type RST-H2, 21.85% curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% catalyst of type PN-40, 0.1% catalyst of zinc acetylacetonate, 0.2% wetting and dispersing agent of type DISPERBYK-102, and 0.05% carbon black of type N700.

[0034] Example 5 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 30.1% of filler of type RST-H2, 11.1% of epoxy resin of type TTA21P, 6.0% of epoxy resin of structural formula (II), 0.2% of coupling agent of type CG-560, and 0.2% of wetting and dispersing agent of type DISPERBYK-102. Component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% of catalyst of type PN-40, 0.1% of catalyst of zinc acetylacetonate, 0.2% of wetting and dispersing agent of type DISPERBYK-102, and 0.05% of carbon black of type N700.

[0035] Example 6 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 30.1% of filler of type RST-H2, 8.1% of epoxy resin of type TTA21P, 9.0% of epoxy resin of structural formula (II), 0.2% of coupling agent of type CG-560 and 0.2% of wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% of catalyst of type PN-40, 0.1% of catalyst of zinc acetylacetonate, 0.2% of wetting and dispersing agent of type DISPERBYK-102 and 0.05% of carbon black of type N700.

[0036] Example 7 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 30.1% of filler of type RST-H2, 11.1% of epoxy resin of type TTA21P, 6.0% of epoxy resin of structural formula (I), 0.2% of coupling agent of type CG-560 and 0.2% of wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methyl nadic anhydride NA, 0.3% of catalyst of type PN-40, 0.1% of catalyst of zinc acetylacetonate, 0.2% of wetting and dispersing agent of type DISPERBYK-102 and 0.05% of carbon black of type N700.

[0037] Example 8 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 30.1% of filler of type RST-H2, 11.1% of epoxy resin of type TTA21P, 6.0% of epoxy resin of structural formula (I), 0.2% of coupling agent of type CG-560 and 0.2% of wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.2% of catalyst of type PN-40, 0.2% of catalyst of type zinc acetylacetonate, 0.2% of wetting and dispersing agent of type DISPERBYK-102 and 0.05% of carbon black of type N700.

[0038] Example 9 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 30.1% of filler of type RST-H2, 11.1% of epoxy resin of type TTA21P, 6.0% of epoxy resin of structural formula (I), 0.2% of coupling agent of type CG-560 and 0.2% of wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% of catalyst of type PN-40, 0.1% of catalyst of type zinc isooctanoate, 0.2% of wetting and dispersing agent of type DISPERBYK-102 and 0.05% of carbon black of type N700.

[0039] Example 10 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 39.3% RST-H2 filler, 7.9% TTA21P epoxy resin, 1.0% TTA800 epoxy resin, 4.0% epoxy resin with structural formula (I), 0.2% CG-560 coupling agent, and 0.2% DISPERBYK-102 wetting and dispersing agent. Component B comprises 29.2% RST-H2 filler, 17.5% methylhexahydrophthalic anhydride (MHHPA) curing agent, 0.3% PN-40 catalyst, 0.1% zinc acetylacetonate catalyst, 0.2% DISPERBYK-102 wetting and dispersing agent, and 0.05% N700 carbon black.

[0040] Example 11 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 39.3% filler of type RST-H2, 5.9% epoxy resin of type TTA21P, 3.0% epoxy resin of type TTA800, 4.0% epoxy resin of structural formula (I), 0.2% coupling agent of type CG-560, and 0.2% wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.2% filler of type RST-H2, 17.5% curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% catalyst of type PN-40, 0.1% catalyst of zinc acetylacetonate, 0.2% wetting and dispersing agent of type DISPERBYK-102, and 0.05% carbon black of type N700.

[0041] Example 12 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 39.3% filler of type RST-H2, 5.9% epoxy resin of type TTA21P, 3.0% epoxy resin of type TTA800, 4.0% epoxy resin of structural formula (II), 0.2% coupling agent of type CG-560 and 0.2% wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.2% filler of type RST-H2, 17.5% curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% catalyst of type PN-40, 0.1% catalyst of zinc acetylacetonate, 0.2% wetting and dispersing agent of type DISPERBYK-102 and 0.05% carbon black of type N700.

[0042] Comparative Example 1 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 30.1% of filler (RST-H2), 10.2% of epoxy resin (TTA21P), 6.90% of bisphenol A epoxy resin 328D, 0.2% of coupling agent (CG-560), and 0.2% of wetting and dispersing agent (DISPERBYK-102). Component B comprises 29.9% of filler (RST-H2), 21.80% of curing agent (methylhexahydrophthalic anhydride MHHPA), 0.4% of catalyst (PN-40), 0.2% of wetting and dispersing agent (DISPERBYK-102), and 0.1% of carbon black (N700).

[0043] Comparative Example 2 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 16.1% of epoxy resin of type TTA21P, 30.1% of filler of type RST-H2, 0.2% of coupling agent of type CG-560 and 0.2% of wetting and dispersing agent of type DISPERBYK-102; component B comprises 22.8% of curing agent of type methylhexahydrophthalic anhydride, 29.9% of filler of type RST-H2, 0.4% of catalyst of type PN-40, 0.2% of wetting and dispersing agent of type DISPERBYK-102 and 0.1% of carbon black of type N700.

[0044] Comparative Example 3 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 30.1% of filler (RST-H2), 14.9% of epoxy resin (TTA21P), 3% of core-shell toughening agent (S0703), 0.2% of coupling agent (CG-560), and 0.2% of wetting and dispersing agent (DISPERBYK-102). Component B comprises 29.9% of filler (RST-H2), 21.0% of curing agent (methylhexahydrophthalic anhydride MHHPA), 0.4% of catalyst (PN-40), 0.2% of wetting and dispersing agent (DISPERBYK-102), and 0.1% of carbon black (N700).

[0045] Comparative Example 4 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B, wherein component A comprises 30.1% filler of type RST-H2, 17.1% epoxy resin of structural formula (III), 0.2% coupling agent of type CG-560, and 0.2% wetting and dispersing agent of type DISPERBYK-102; component B comprises 29.9% filler of type RST-H2, 21.85% curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% catalyst of type PN-40, 0.1% catalyst of zinc acetylacetonate, 0.2% wetting and dispersing agent of type DISPERBYK-102, and 0.05% carbon black of type N700.

[0046] Comparative Example 5 A crack-resistant and high-temperature resistant epoxy potting compound, by mass fraction, comprises component A and component B. Component A comprises 30.1% of filler of type RST-H2, 17.1% of epoxy resin of structural formula (IV), 0.2% of coupling agent of type CG-560, and 0.2% of wetting and dispersing agent of type DISPERBYK-102. Component B comprises 29.9% of filler of type RST-H2, 21.85% of curing agent of type methylhexahydrophthalic anhydride MHHPA, 0.3% of catalyst of type PN-40, 0.1% of catalyst of zinc acetylacetonate, 0.2% of wetting and dispersing agent of type DISPERBYK-102, and 0.05% of carbon black of type N700.

[0047] To clearly compare the dosages of each embodiment and comparative example, the specific dosages are shown in Tables 1-3.

[0048] Table 1

[0049] Table 2

[0050] Table 3

[0051] The performance of the crack-resistant and high-temperature-resistant epoxy potting compounds prepared in Examples 1 to 12 and Comparative Examples 1 to 5 was tested, and the test methods are as follows: 1) Viscosity test: The viscosity was tested according to the method in GB / T 22314-2008; 2) Curing shrinkage test: The curing shrinkage test shall be conducted in accordance with the method of ISO 3521:1997; 3) Glass transition temperature (Tg) test: The glass transition temperature was tested according to the method in GB / T22567-2008; 4) Aging and Cracking Test: The cracking of epoxy-encapsulated devices stored at 225℃ for 72 hours was tested according to GB / T 2423.2-2008. Figure 2 As shown.

[0052] The data obtained from the tests conducted using the methods described above are shown in Tables 4-6.

[0053] Table 4

[0054] Table 5

[0055] Table 6

[0056] According to the test results in Tables 4 to 6, the present invention uses a combination of a polyfunctional alicyclic epoxy resin with flexible segments and a difunctional alicyclic epoxy resin, and uses imidazole and organozinc catalysts in a certain proportion to significantly reduce the curing shrinkage rate of epoxy potting compound and has a high glass transition temperature. When applied to the packaging of automotive electronic components such as rectifier diodes and power modules, it has excellent crack resistance and high temperature resistance.

[0057] According to the comparison of the examples and Comparative Examples 1-3, it can be seen that using only a single difunctional alicyclic epoxy resin, or a combination of difunctional alicyclic epoxy resin and ordinary bisphenol A epoxy resin, or even adding a toughening agent to a single difunctional alicyclic epoxy resin, although the glass transition temperature is increased, the aging cracking performance is significantly reduced. As can be seen from the comparison of the examples and Comparative Examples 4-5, using only difunctional alicyclic epoxy resins containing long flexible segments significantly reduces the glass transition temperature, resulting in insufficient aging and cracking performance. Using only high-viscosity polyfunctional alicyclic epoxy resins containing flexible segments severely reduces potting workability, making it unsuitable for application conditions.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A crack-resistant, high-temperature resistant epoxy potting compound, characterized in that: By mass fraction, it includes component A and component B, wherein the total mass of components A and B is 100%; Component A comprises 12-18% epoxy resin, 25-45% first filler, 0.1-0.5% coupling agent and 0.1-0.5% first wetting and dispersing agent; Component B comprises 15-25% curing agent, 25-35% second filler, 0.1-0.6% catalyst, 0.1-0.5% second wetting and dispersing agent, and 0.05-0.2% carbon black; The epoxy resin is composed of a difunctional alicyclic epoxy resin and a multifunctional alicyclic epoxy resin containing flexible segments. The mass percentage of the polyfunctional alicyclic epoxy resin containing flexible segments is 10-50% of the total epoxy resin. The difunctional alicyclic epoxy resin is selected from at least one of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester and 3,4,3',4'-diepoxydicyclohexane; The multifunctional alicyclic epoxy resin containing flexible segments is selected from at least one of structural formula (I) and structural formula (II); 。 2. The crack-resistant and high-temperature resistant epoxy potting compound according to claim 1, characterized in that: The curing agent is selected from at least one of methylhexahydrophthalic anhydride and methylnadic anhydride.

3. The crack-resistant and high-temperature resistant epoxy potting compound according to claim 1, characterized in that: The catalyst is selected from at least one of imidazole catalysts and organozinc catalysts.

4. The crack-resistant and high-temperature resistant epoxy potting compound according to claim 3, characterized in that: The imidazole catalyst is selected from at least one of 2-methylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenyl-4-methylimidazolium, and 2,4-diamino-6-[2-(2-methyl-1-imidazolium)ethyl]-1,3,5-triazine; The organozinc catalyst is selected from zinc isooctanoate and zinc acetylacetonate.

5. The crack-resistant and high-temperature resistant epoxy potting compound according to claim 3, characterized in that: The catalyst is composed of an imidazole catalyst and an organozinc catalyst, wherein the mass ratio of the imidazole catalyst to the organozinc catalyst is 1 to 5:

1.

6. The crack-resistant and high-temperature resistant epoxy potting compound according to claim 1, characterized in that: The coupling agent is selected from at least one of γ-glycidyl ether propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and phenylaminopropyltrimethoxysilane; The first filler and the second filler are independently selected from at least one of angular silica and spherical silica; The first wetting and dispersing agent and the second wetting and dispersing agent are independently selected from at least one of DISPERBYK-118, DISPERBYK-102, and DISPERBYK-2152.

7. A method for preparing the crack-resistant, high-temperature-resistant epoxy potting compound according to any one of claims 1 to 6, characterized in that: Includes the following steps: Preparation of Component A: Epoxy resin, coupling agent and first wetting and dispersing agent are premixed, then the first filler is added, and the mixture is stirred at 40~50℃ and degassed under vacuum to obtain Component A; Preparation of component B: The curing agent, the second wetting and dispersing agent, the catalyst and carbon black are premixed, and then the second filler is added. The mixture is stirred at 40~50℃ and degassed under vacuum to obtain component B.

8. The application of an epoxy potting compound according to any one of claims 1 to 6 or an epoxy potting compound prepared according to the method of claim 7 as an encapsulating adhesive in automotive electronic components.

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