Epoxy pouring sealant as well as preparation method and application thereof

Abstract

The invention discloses an epoxy pouring sealant as well as a preparation method and application thereof. The epoxy pouring sealant comprises a first composition and a second composition, the first composition comprises a mixed curing agent, silicon oxide microspheres and a silane coupling agent, the mixed curing agent comprises an end-capping reagent and polyamino aromatic amine, the end-capping reagent comprises a compound shown in the formula 1, and R1-R5 are independently hydrogen or C1-C5 substituted or unsubstituted branched or linear alkyl; r6 is a substituted or unsubstituted aryl group of C6-C10, a cycloalkyl group of C3-C8, and a substituted or unsubstituted branched or linear alkyl group of C1-C12; the second composition comprises epoxy resin, silicon oxide microspheres and a silane coupling agent. Therefore, the cured epoxy resin can be ensured to have high Tg and lower high-temperature storage modulus.

Description

Technical Field

[0001] The present application relates to the field of packaging materials, and in particular to epoxy potting adhesives, preparation methods, and applications thereof. Background Art

[0002] With the rapid growth of the new energy vehicle market, demand for power devices, core components of the three-electric system of new energy vehicles, is also increasing. However, due to the large losses, the operating temperature of power devices is relatively high, which places higher reliability requirements on the packaging materials, which must have higher high-temperature resistance. When the packaging material is applied to the operating temperature of the device, on the one hand, it needs to maintain thermodynamic stability. Therefore, the packaging material is required to have a high glass transition temperature (Tg) to ensure that the packaging material does not transform from the glass state to the rubber state within the operating temperature range. On the other hand, to reduce the thermal stress on the device, the packaging material should have a lower storage modulus at higher temperatures so that it can absorb and dissipate more energy, thereby avoiding package failure or device damage due to thermal stress.

[0003] However, current packaging materials used for power devices still need to be improved. Summary of the Invention

[0004] The present application aims to alleviate or solve at least one of the above-mentioned problems to at least some extent.

[0005] In one aspect of the present application, an epoxy potting compound is provided. In some embodiments of the present application, the epoxy potting compound includes a first composition and a second composition, wherein the first composition includes a mixed curing agent, silica microspheres, and a silane coupling agent, the mixed curing agent includes a capping agent and a polyamino aromatic amine, and the capping agent includes a compound represented by Formula 1. wherein R1 to R5 are each independently hydrogen or a C1 to C5 substituted or unsubstituted, branched or linear alkyl group; R6 is a C6 to C 10 Substituted or unsubstituted aryl, C3~C8 cycloalkyl, C1~C 12 The second composition comprises an epoxy resin, silica microspheres, and a silane coupling agent. The polyamino aromatic amine thus makes the cross-linked network of the epoxy resin obtained after curing more complex, thereby increasing the cross-linking density. Furthermore, the benzene rings in the aromatic amine also impart a rich rigid structure to the cross-linked network. These two factors work together to ensure that the cured epoxy resin has a high Tg (glass transition temperature). Aromatic amines containing secondary amines (-NH-) can terminate the epoxy chains, thereby reducing the cross-linking density of the resin system. Furthermore, the terminated epoxy resin chains can also serve as flexible branches, which together result in a lower high-temperature storage modulus.

[0006] In some embodiments of the present application, the molar ratio of active hydrogen in the first composition to epoxy group in the second composition is 0.85-1.1.

[0007] In some embodiments of the present application, the molar ratio of active hydrogen in the first composition to epoxy group in the second composition is 0.9-1.

[0008] In some embodiments of the present application, R6 is cyclohexyl, phenyl, benzyl or methyl.

[0009] In some embodiments of the present application, the end-capping agent satisfies one of the following conditions: R1-R5 is hydrogen; R1 is ethyl and R2-R5 is hydrogen; R1 is methylmercapto and R2-R5 is hydrogen; R3 is ethyl and R1, R2, R4, R5 is hydrogen; R1, R5 is isopropyl and R2, R3, R4 is hydrogen; R3 is propyl and R1, R2, R4, R5 is hydrogen; R1, R5 is ethyl and R2, R3, R4 is hydrogen.

[0010] In some embodiments of the present application, the mixed curing agent comprises an end-capping agent with a weight percentage of 16.3%-24% and a polyamine-based aromatic amine with a weight percentage of 76%-82%; and / or, the polyamine-based aromatic amine comprises one or more of diethyltoluene diamine, 4'4 methylene bis(2,6-diethyl aniline).

[0011] In some embodiments of the present application, the epoxy potting compound satisfies at least one of the following conditions: the Dv50 particle size of the silica microspheres in the first composition and the silica microspheres in the second composition is independently 1-100 μm; the silane coupling agent in the first composition and the silane coupling agent in the second composition independently comprises one or more of KH560 silane coupling agent, KH570 silane coupling agent and KH590 silane coupling agent; the epoxy resin comprises one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, triglycidyl ether p-aminophenol, phenolic epoxy resin.

[0012] In some embodiments of the present application, the first composition further comprises a first auxiliary agent, and optionally, the first auxiliary agent comprises a defoaming agent and a leveling agent; the second composition further comprises a second auxiliary agent, and optionally, the second auxiliary agent comprises a toughening agent, a defoaming agent and a leveling agent.

[0013] In some embodiments of the present application, the first composition comprises: 11% to 21.5% of mixed curing agent by weight percentage; 77% to 87.55% of silica microspheres by weight percentage; 1.15% to 1.35% of silane coupling agent by weight percentage; 0.01% to 0.1% of first additive by weight percentage; and the second composition comprises: 12.7% to 15% of epoxy resin by weight percentage; 81% to 84% of silica microspheres by weight percentage; 1.2% to 1.4% of silane coupling agent by weight percentage; 1.54% to 1.98% of second additive by weight percentage.

[0014] In some embodiments of the present application, the first composition comprises: 11% to 21.5% of mixed curing agent by weight percentage; 77% to 87.55% of silica microspheres by weight percentage; 1.15% to 1.35% of silane coupling agent by weight percentage; 0.005% to 0.05% of defoaming agent by weight percentage; 0.005% to 0.05% of leveling agent by weight percentage; and the second composition comprises: 12.7% to 15% of epoxy resin by weight percentage; 81% to 84% of silica microspheres by weight percentage; 1.2% to 1.4% of silane coupling agent by weight percentage; 0.02% to 0.04% of defoaming agent by weight percentage; 0.02% to 0.04% of leveling agent by weight percentage; and 1.5% to 1.9% of toughening agent by weight percentage.

[0015] In another aspect of the present application, a method for preparing the epoxy pouring sealant described above is provided. In some embodiments of the present application, the method for preparing the epoxy pouring sealant described above comprises: mixing monoamine-based aromatic amine and maleimide to obtain an end-capping agent by heating reaction, wherein the monoamine-based aromatic amine comprises a compound shown in Formula 2, and the maleimide comprises a compound shown in Formula 3,

[0016] wherein R1 to R5 are each independently hydrogen or C1 to C5 substituted or unsubstituted, branched or straight-chain alkyl; and R6 is C6 to C 10 substituted or unsubstituted aryl, C3 to C8 cycloalkyl, C1 to C 12 substituted or unsubstituted, branched or straight-chain alkyl; mixing the end-capping agent, polyamine-based aromatic amine, silica microspheres and silane coupling agent to obtain a first composition; and mixing epoxy resin, silica microspheres and silane coupling agent to obtain a second composition. The epoxy pouring sealant prepared by the above method has a relatively high glass transition temperature after curing, and has a relatively low storage modulus after curing at a relatively high temperature, thereby avoiding encapsulation failure or device damage caused by thermal stress.

[0017] In some embodiments of the present application, the temperature of the heating reaction is 60-85℃, and / or the time of the heating reaction is 10-30 minutes.

[0018] In some embodiments of the present application, the method for preparing the aforementioned epoxy potting adhesive satisfies at least one of the following conditions: the monoamine-based aromatic amine includes one or more of 2-ethylaniline, 2-methylmercaptobenzene, 4-ethylaniline, 2,6-diisopropylaniline, p-propylaniline, and 2,6-diethylaniline; the maleimide includes one or more of N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide, and N-methylmaleimide.

[0019] In some embodiments of the present application, the end-capping agent is mixed with the polyamine-based aromatic amine to obtain a mixture, and the mixture is mixed with the silica microspheres, the silane coupling agent, and the first auxiliary agent to obtain the first composition; the epoxy resin, the silica microspheres, the silane coupling agent, and the second auxiliary agent are mixed to obtain the second composition.

[0020] In yet another aspect of the present application, the present application provides the use of the aforementioned epoxy potting adhesive in a power device. The epoxy potting adhesive can be used to package the power device, and the packaging effect is good. Moreover, at the working temperature of the power device, packaging failure or damage of the power device caused by thermal stress can be at least to some extent avoided. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The raw materials of the end-capping agent and the FTIR (Fourier Transform Infrared Spectroscopy) diagram of the end-capping agent in Example 1 are shown. DETAILED DESCRIPTION

[0022] The embodiments of the present application are described in detail below, and the embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0023] At present, epoxy resin is widely used as a plastic packaging material on the market. In order to increase the Tg (glass transition temperature) of the cured epoxy resin, the approaches of increasing the crosslinking density and introducing rigid structures can be used to achieve, however, this will also increase the storage modulus of the cured material. In order to reduce the storage modulus of the cured epoxy resin, the epoxy resin with flexible chains (such as hyperbranched epoxy resin, silicone-modified epoxy resin, polyurethane-modified epoxy resin, etc.), toughening rubber, and curing agents with flexible chains are often used for improvement, however, these materials are not conducive to the improvement of the Tg of the cured epoxy resin. Therefore, it is necessary to find a balance between the Tg and the storage modulus, and to develop a potting adhesive product which still has a low high-temperature storage modulus while ensuring that the Tg of the cured epoxy resin is not reduced.

[0024] In one aspect, the present application provides an epoxy potting compound. In some embodiments of the present application, the epoxy potting compound comprises a first composition and a second composition. The first and second compositions react after mixing and can be stored separately before use. Separate storage refers to storing the first and second compositions in different containers. When the epoxy potting compound is needed for packaging, the first and second compositions can be mixed.

[0025] In some embodiments of the present application, the first composition includes a mixed curing agent, silica microspheres, and a silane coupling agent, wherein the mixed curing agent may include a capping agent and a polyamino aromatic amine. In some embodiments of the present application, the second composition includes an epoxy resin, silica microspheres, and a silane coupling agent. The capping agent includes a compound shown in Formula 1, wherein R1 to R5 are each independently hydrogen or a C1 to C5 substituted or unsubstituted, branched or linear alkyl group; R6 is a C6 to C 10 Substituted or unsubstituted aryl, C3~C8 cycloalkyl, C1~C 12 a substituted or unsubstituted, branched or straight-chain alkyl group.

[0026] Therefore, polyamino aromatic amines bring high cross-linking density to epoxy resins, and aromatic amines provide epoxy resins with a rigid structure. The two together ensure the high Tg (glass transition temperature) of the epoxy potting compound after curing. Aromatic amines with secondary amines (-NH-) can act as end-capping terminals, providing flexible long chains for epoxy resins and reducing the modulus of epoxy resins after curing.

[0027] "C1-C5 substituted or unsubstituted, branched or linear alkyl group" refers to a branched or straight-chain alkyl group having 1, 2, 3, 4 or 5 carbon atoms. One or more hydrogen atoms in the alkyl group may be substituted by a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or other substituents, or may be unsubstituted.

[0028] "C6~C 10 The term "substituted or unsubstituted aryl group" refers to a structure containing a benzene ring and having 6, 7, 8, 9 or 10 carbon atoms. One or more hydrogen atoms of the aryl group may be substituted by a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or other substituents, or may be unsubstituted.

[0029] The number of carbon atoms in the "C3-C8 cycloalkyl group" can be 3, 4, 5, 6, 7 or 8, and it contains a cyclic structure.

[0030] “C1~C 12The "substituted or unsubstituted, branched or straight-chain alkyl group having 1 to 12 carbon atoms" refers to a branched or straight-chain alkyl group having 1 to 12 carbon atoms (for example, 1, 2, 4, 6, 8, 10, or 12), in which one or more hydrogen atoms can be substituted with a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or the like, or other substituent, or can not be substituted.

[0031] In some embodiments of the present application, R6 is a cyclohexyl group, a phenyl group, a benzyl group, or a methyl group.

[0032] In some embodiments of the present application, R1 to R5 in formula 1 are hydrogen.

[0033] In some embodiments of the present application, R1 to R5 in formula 1 are hydrogen.

[0034] In some embodiments of the present application, R1 to R5 in formula 1 are hydrogen.

[0035] In some embodiments of the present application, R1 to R5 in formula 1 are hydrogen.

[0036] In some embodiments of the present application, R1 to R5 in formula 1 are hydrogen.

[0037] In some embodiments of the present application, R1 to R5 in formula 1 are hydrogen.

[0038] In some embodiments of the present application, R1 to R5 in formula 1 are hydrogen.

[0039] In some embodiments of the present application, the molar ratio of the active hydrogen in the first composition to the epoxy group in the second composition can be 0.85 to 1.1, for example, the molar ratio of the active hydrogen in the first composition to the epoxy group in the second composition can be 0.85, 0.88, 0.92, 0.95, 0.98, 1.03, 1.05, 1.08, or 1.1. In this way, the molar ratio of the active hydrogen to the epoxy group is within a suitable range, which is conducive to further balancing the glass transition temperature and the storage modulus of the epoxy potting compound, so that the epoxy potting compound has more excellent performance.

[0040] In the present application, the active hydrogen refers to the hydrogen atom in the amine group.

[0041] In some embodiments of the present application, the molar ratio of active hydrogen in the first composition and epoxy groups in the second composition can be 0.9-1, for example, the ratio can be 0.9, 0.93, 0.96, 0.98 or 1. Thereby, the performance of the epoxy potting compound can be further improved.

[0042] In some embodiments of the present application, the mixed curing agent can include a blocking agent with a weight percentage of 16.3%-24% and a polyamine-based aromatic amine with a weight percentage of 76%-82%, for example, the weight percentage of the blocking agent in the mixed curing agent can be 16.3%, 17%, 19%, 22% or 24%, and the weight percentage of the polyamine-based aromatic amine can be 76%, 78%, 80% or 82%.

[0043] In some embodiments of the present application, the mixed curing agent can be composed of a blocking agent and a polyamine-based aromatic amine, for example, the mixed curing agent can be composed of 76%, 78%, 80% or 82% of the polyamine-based aromatic amine and the rest of the blocking agent.

[0044] In some other embodiments of the present application, in addition to the blocking agent and the polyamine-based aromatic amine, the mixed curing agent can also include a monoamine-based aromatic amine and / or a maleimide. In some embodiments, the mixed curing agent can be composed of a blocking agent with a weight percentage of 16.3%-23.8%, a polyamine-based aromatic amine with a weight percentage of 76%-82% and the rest of a monoamine-based aromatic amine or a maleimide. In some other embodiments, the mixed curing agent can be composed of a blocking agent with a weight percentage of 16.3%-23.8%, a polyamine-based aromatic amine with a weight percentage of 76%-82% and the rest of a monoamine-based aromatic amine and / or a maleimide.

[0045] In some embodiments of the present application, the polyamine-based aromatic amine can include one or more of diethyl toluene diamine (for example, 2,4-diamino-3,5-diethyl toluene 3,5-diethyl toluene-2,6-diamine ), 4'4 methylene bis (2,6-diethyl aniline) The above polyamine-based aromatic amine can make the crosslinking network of the cured epoxy resin more complex, improve the crosslinking density, and the benzene ring can endow the crosslinking network with rich rigid structure, thereby facilitating the improvement of the glass transition temperature of the cured epoxy potting compound.

[0046] In some embodiments of the present application, the Dv50 particle size of the silica microspheres in the first composition and the silica microspheres in the second composition can each independently be 1-100 pm, for example, the Dv50 particle size of the silica microspheres can be 1 pm, 5 pm, 10 pm, 50 pm, 80 pm, 100 pm, etc. The addition of silica microspheres with the above-mentioned particle size in the first composition and the second composition is beneficial to regulating the expansion coefficient of the epoxy potting compound and improving the mechanical strength after curing, thereby further improving the overall performance of the epoxy potting compound, so that it can be used for packaging power devices.

[0047] In some embodiments of the present application, the silane coupling agent in the first composition and the silane coupling agent in the second composition can each independently include one or more of KH560 silane coupling agent, KH570 silane coupling agent, and KH590 silane coupling agent. The above-mentioned silane coupling agent can improve the bonding strength of the epoxy potting compound, improve the dispersibility of fillers (such as silica microspheres) in the epoxy potting compound, and is beneficial to enhancing the mechanical strength of the epoxy potting compound after curing.

[0048] In some embodiments of the present application, the epoxy resin can include one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, triglycidyl ether p-aminophenol, and phenolic epoxy resin.

[0049] In some embodiments of the present application, the first composition further includes a first auxiliary agent. In some embodiments, the first auxiliary agent can include a defoaming agent (such as BYK-1799) and a leveling agent (such as BYK-9076).

[0050] In some embodiments of the present application, the first composition can include: a mixed curing agent with a weight percentage of 11-21.5% (for example, 11%, 13%, 15%, 18%, 20%, 21.5%, etc.); silica microspheres with a weight percentage of 77-87.55% (for example, 77%, 79%, 80%, 82%, 85%, 86%, 87.55%, etc.); a silane coupling agent with a weight percentage of 1.15-1.35% (for example, 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, etc.); and a first auxiliary agent with a weight percentage of 0.01-0.1% (for example, 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, etc.). The content of each component in the first composition within the appropriate range is beneficial to improving the uniformity and stability of the first composition.

[0051] In some embodiments of the present application, the first composition can include a mixed curing agent with a weight percentage of 11% to 21.5%; silica microspheres with a weight percentage of 77% to 87.55%; a silane coupling agent with a weight percentage of 1.15% to 1.35%; an antifoaming agent with a weight percentage of 0.005% to 0.05% (e.g., 0.005%, 0.008%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, etc.); and a leveling agent with a weight percentage of 0.005% to 0.05% (e.g., 0.005%, 0.008%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, etc.). Thus, the uniformity and stability of the first composition can be further improved.

[0052] In some embodiments of the present application, the second composition can include a second auxiliary agent in addition to the epoxy resin, the silica microspheres, and the silane coupling agent. In some embodiments, the second auxiliary agent can include a toughening agent with a core-shell structure, an antifoaming agent (e.g., BYK-1799), and a leveling agent (e.g., BYK-9076).

[0053] In some embodiments, the toughening agent can include one or more of a nano-particle with a core-shell structure, a nano-particle expanding agent, and hollow glass microbeads.

[0054] In some embodiments of the present application, the second composition can include an epoxy resin with a weight percentage of 12.7% to 15% (e.g., 12.7%, 13%, 13.5%, 14%, 14.5%, 15%, etc.); silica microspheres with a weight percentage of 81% to 84% (e.g., 81%, 81.5%, 82%, 82.5%, 83%, 83.5%, 84%, etc.); a silane coupling agent with a weight percentage of 1.2% to 1.4% (e.g., 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, etc.); and a second auxiliary agent with a weight percentage of 1.54% to 1.98% (e.g., 1.54%, 1.57%, 1.6%, 1.7%, 1.8%, 1.9%, 1.98%, etc.). Thus, the uniformity and stability of the second composition can be improved.

[0055] In some embodiments of the present application, the second composition comprises: 12.7% to 15% by weight of epoxy resin; 81% to 84% by weight of silica microspheres; 1.2% to 1.4% by weight of silane coupling agent; 0.02% to 0.04% (e.g. 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, etc.) by weight of defoaming agent; 0.02% to 0.04% (e.g. 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, etc.) by weight of leveling agent; 1.5% to 1.9% (e.g. 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, etc.) by weight of toughening agent. Thus, the uniformity and stability of the second composition can be further improved.

[0056] In some embodiments of the present application, the mass ratio of the first composition to the second composition can be 10:17 when the epoxy potting adhesive is used.

[0057] In some embodiments of the present application, color powder can also be added to the epoxy potting adhesive to make the epoxy potting adhesive have a desired color.

[0058] In some embodiments of the present application, the formula of the epoxy potting adhesive can be prepared into epoxy molding compound for other packaging forms.

[0059] In another aspect of the present application, the present application provides a method for preparing the epoxy potting adhesive described above. In some embodiments of the present application, the method for preparing the epoxy potting adhesive described above comprises the following steps:

[0060] S10: mixing the monoamine-based aromatic amine with the maleimide and performing a heating reaction to obtain an end-capping agent.

[0061] In some embodiments of the present application, the monoamine-based aromatic amine can comprise a compound shown in Formula 2.

[0062] wherein R1 to R5 are each independently hydrogen or a C1 to C5 substituted or unsubstituted, branched or straight alkyl group.

[0063] In some embodiments of the present application, the maleimide can comprise a compound shown in Formula 3.

[0064] wherein R6 is a C6 to C 10 substituted or unsubstituted aryl group, a C3 to C8 cycloalkyl group, a C1 to C 12 substituted or unsubstituted, branched or straight alkyl group.

[0065] The mono-amine aromatic amine and the maleimide can react to generate the capping agent shown in Formula 1 under the condition of heating. The capping agent has a secondary amine, which can cap the cross-linking polymerization reaction of the epoxy resin, thereby reducing the cross-linking density of the epoxy resin system. In addition, the capped epoxy resin chain can also serve as a flexible branch, thereby reducing the high-temperature storage modulus of the cured epoxy resin system.

[0066] In some embodiments of the present application, the mono-amine aromatic amine can include 2-ethylaniline 2-methylthioaniline 4-ethylaniline 2,6-diisopropylaniline p-propylaniline 2,6-diethylaniline one or more of them.

[0067] In some embodiments of the present application, the maleimide can include N-cyclohexylmaleimide

[0068] N-benzylmaleimide N-phenylmaleimide N-methylmaleimide one or more of them.

[0069] In some embodiments of the present application, the temperature of the heating reaction can be 60-85°C, for example, the temperature of the heating reaction can be 60°C, 65°C, 70°C, 75°C, 85°C, etc. At the above temperature, the mono-amine aromatic amine and the maleimide can react to generate the capping agent shown in Formula 1.

[0070] In some embodiments of the present application, the time of the heating reaction can be 10-30 min, for example, the time of the heating reaction can be 10 min, 15 min, 20 min, 25 min, 30 min, etc. In this way, the mono-amine aromatic amine and the maleimide can fully react, thereby facilitating the improvement of the utilization rate of raw materials and the amount of the capping agent.

[0071] In some embodiments of the present application, the addition amount of the mono-amine aromatic amine can be 4.3-5.5 parts by weight (for example, 4.3 parts by weight, 4.5 parts by weight, 4.8 parts by weight, 5 parts by weight, 5.3 parts by weight, 5.5 parts by weight, etc.), and the addition amount of the maleimide can be 12-20 parts by weight (for example, 12 parts by weight, 14 parts by weight, 15 parts by weight, 17 parts by weight, 20 parts by weight, etc.).

[0072] S20: mixing the capping agent with the poly-amine aromatic amine, the silica microspheres, and the silane coupling agent to obtain a first composition.

[0073] In some embodiments of the present application, the end-capping agent can be mixed with the polyamine-based aromatic amine to obtain a mixed curing agent, and then the mixed curing agent can be mixed with the silica microspheres and the silane coupling agent to obtain a first mixture.

[0074] In some embodiments of the present application, the end-capping agent can be mixed with the polyamine-based aromatic amine to obtain a mixed curing agent, and then the mixed curing agent can be mixed with the silica microspheres and the silane coupling agent to obtain a first mixture.

[0075] In some embodiments of the present application, the end-capping agent can be mixed with the polyamine-based aromatic amine to obtain a mixed curing agent, and then the mixed curing agent can be mixed with the silica microspheres and the silane coupling agent to obtain a first mixture.

[0076] The types and contents of the polyamine-based aromatic amine, the silica microspheres, the silane coupling agent, and the first additive have been described above, and will not be repeated here.

[0077] S30: mixing the epoxy resin, the silica microspheres, and the silane coupling agent to obtain a second composition.

[0078] In some embodiments of the present application, the epoxy resin, the silica microspheres, and the silane coupling agent can be mixed in a homogenizer.

[0079] In some embodiments of the present application, the epoxy resin, the silica microspheres, and the silane coupling agent can be mixed in a homogenizer.

[0080] In some embodiments of the present application, the epoxy resin, the silica microspheres, and the silane coupling agent can be mixed in a homogenizer.

[0081] The types and contents of the epoxy resin, the silica microspheres, the silane coupling agent, and the second additive have been described above, and will not be repeated here.

[0082] In some embodiments of the present application, the epoxy resin, the silica microspheres, and the silane coupling agent can be mixed in a homogenizer.

[0083] The epoxy potting adhesive prepared by the above method has simple preparation steps and low cost.

[0084] In another aspect of the present application, the application provides the use of the above-mentioned epoxy potting adhesive in power devices. The above-mentioned epoxy potting adhesive has a high glass transition temperature and a low high-temperature storage modulus after curing. When the epoxy potting adhesive is used to encapsulate power devices, the cured epoxy potting adhesive can maintain good stability at the working temperature of the device and is not prone to thermal stress, which is conducive to avoiding encapsulation failure or device damage caused by thermal stress.

[0085] In some embodiments of the present application, the power device can be a SiC module, an IGBT module, etc.

[0086] The present application will be described below by way of specific examples, and it will be understood by those skilled in the art that the specific examples below are for illustrative purposes only and do not limit the scope of the present application in any way. In addition, in the following examples, unless otherwise specified, the materials and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following examples, the conditions and methods known in the art can be used for processing.

[0087] Example 1

[0088] The manufacturing process of the epoxy pouring sealant is as follows: ① 2-ethylaniline and N-cyclohexylmaleimide are mixed and heated to react, the heating temperature is 80°C, and the heating time is 15 min. The reaction product is added to diethyltoluene diamine to mix uniformly to obtain a mixed curing agent; ② the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent, and leveling agent are mixed uniformly in a homogenizer to obtain a mixture; ③ bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, silica microspheres, silane coupling agent, defoaming agent, and leveling agent are mixed uniformly in a homogenizer to obtain a mixture; ④ the mixtures obtained in steps ② and ③ are mixed uniformly in a homogenizer under vacuum to obtain an epoxy pouring sealant with high Tg and low modulus after curing.

[0089] In step ①, the components and weight percentage contents are as follows: 2-ethylaniline: 4.54%; N-cyclohexylmaleimide resin: 13.64%; diethyltoluene diamine: 81.82%.

[0090] In step ②, the components and weight percentage contents are as follows: mixed curing agent: 11.23%; silica microspheres: 87.42%; silane coupling agent KH560: 1.296%; defoaming agent BYK-1799: 0.027%; leveling agent BYK-9076: 0.027%.

[0091] In step ③, the components and weight percentage contents are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl-p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent KH560: 1.22%; defoaming agent BYK-1799: 0.03%; leveling agent BYK-9076: 0.03%; toughening agent: 1.79%.

[0092] In step ④, the molar ratio of active hydrogen to epoxy groups in steps ② and ③ is 0.9.

[0093] Example 2

[0094] The manufacturing process of the epoxy potting adhesive is as follows: ① 2- ethylaniline and N-phenylmaleimide are mixed and heated to react, the heating temperature is 80℃, and the heating time is 15 min. The reaction product is added into diethyltoluene diamine to be uniformly mixed to obtain a mixed curing agent; ② the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent, and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ③ bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, silica microspheres, silane coupling agent, defoaming agent, and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ④ the mixtures obtained in steps ② and ③ are uniformly mixed in a homogenizer under vacuum to obtain the epoxy potting adhesive with high Tg and low modulus after curing.

[0095] In step ①, the components and weight percentage contents are as follows: 2- ethylaniline: 5.41%; N-phenylmaleimide resin: 18.02%; diethyltoluene diamine: 76.57%.

[0096] In step ②, the components and weight percentage contents are as follows: mixed curing agent: 13.43%; silica microspheres: 85.25%; silane coupling agent: 1.26%; defoaming agent: 0.03%; leveling agent: 0.03%.

[0097] In step ③, the components and weight percentage contents are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl-p- aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%; toughening agent: 1.79%.

[0098] In step ④, the molar ratio of active hydrogen to epoxy group in steps ② and ③ is ensured to be 1.

[0099] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p- aminophenol, toughening agent, silane coupling agent, defoaming agent, and leveling agent used in Example 2 are the same as those in Example 1.

[0100] Example 3

[0101] The preparation process of the epoxy potting adhesive is: ① heating and reacting p-propyl aniline and N-benzyl maleimide, the heating temperature is 80℃, and the heating time is 15 min. The reaction product is added into diethyl toluene diamine to be uniformly mixed to obtain a mixed curing agent; ② uniformly mixing the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent in a homogenizer to obtain a mixture; ③ uniformly mixing bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent in a homogenizer to obtain a mixture; ④ uniformly mixing the mixtures obtained in steps ② and ③ in a homogenizer under vacuum to obtain the potting adhesive with high Tg and low modulus after curing.

[0102] The components and weight percentage contents in step ① are as follows: p-propyl aniline: 4.76%; N-benzyl maleimide resin: 14.29%; diethyl toluene diamine: 80.95%.

[0103] The components and weight percentage contents in step ② are as follows: mixed curing agent: 11.39%; silica microspheres: 87.27%; silane coupling agent: 1.29%; defoaming agent: 0.025%; leveling agent: 0.025%.

[0104] The components and weight percentage contents in step ③ are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%; toughening agent: 1.79%.

[0105] In step ④, the molar ratio of active hydrogen and epoxy groups in steps ② and ③ is 0.9.

[0106] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, toughening agent, silane coupling agent, defoaming agent and leveling agent used in example 3 are the same as those in example 1.

[0107] Example 4

[0108] The preparation process of the epoxy potting adhesive in Example 4 is as follows: ① 2-ethylaniline and N-cyclohexyl maleimide are mixed and heated to react, the heating temperature is 80℃, and the heating time is 15 min. The reaction product is added into 4'4 methylene bis(2, 6-diethylaniline) and uniformly mixed to obtain a mixed curing agent; ② the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ③ bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ④ the mixtures obtained in steps ② and ③ are uniformly mixed in a homogenizer under vacuum to obtain the epoxy potting adhesive with high Tg and low modulus after curing.

[0109] The components and weight percentage in step ① are as follows: 2-ethylaniline: 4.35%; N-cyclohexyl maleimide resin: 17.39%; 4'4 methylene bis(2, 6-diethylaniline): 78.26%.

[0110] The components and weight percentage in step ② are as follows: mixed curing agent: 20.92%; silica microspheres: 77.88%; silane coupling agent: 1.15%; defoaming agent: 0.025%; leveling agent: 0.025%.

[0111] The components and weight percentage in step ③ are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl-p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%; toughening agent: 1.79%.

[0112] In step ④, the molar ratio of active hydrogen and epoxy groups in steps ② and ③ is 0.9.

[0113] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, toughening agent, silane coupling agent, defoaming agent and leveling agent used in Example 4 are the same as those in Example 1.

[0114] Example 5

[0115] The preparation process of the epoxy potting adhesive is as follows: ①p-Propyl aniline is mixed with N-cyclohexyl maleimide and heated to react, the heating temperature is 80℃, and the heating time is 15 min. The reaction product is added into diethyl toluene diamine to be uniformly mixed to obtain a mixed curing agent; ②the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ③bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ④the mixtures obtained in steps ② and ③ are uniformly mixed in a homogenizer under vacuum to obtain the epoxy potting adhesive with high Tg and low modulus after curing.

[0116] The components and weight percentage of step ① are as follows: 2,6-diisopropyl aniline: 4.76%; N-cyclohexyl maleimide resin: 14.29%; diethyl toluene diamine: 80.95%.

[0117] The components and weight percentage of step ② are as follows: mixed curing agent: 11.52%; silica microspheres: 87.13%; silane coupling agent: 1.29%; defoaming agent: 0.03%; leveling agent: 0.03%.

[0118] The components and weight percentage of step ③ are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%; toughening agent: 1.79%.

[0119] In step ④, the molar ratio of active hydrogen and epoxy groups in steps ② and ③ is 0.9.

[0120] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, toughening agent, silane coupling agent, defoaming agent and leveling agent used in example 5 are the same as those in example 1.

[0121] Example 6

[0122] The preparation process of the epoxy potting adhesive is as follows: ①2-ethylaniline and N-methyl maleimide are mixed and heated to react, the heating temperature is 80℃, and the heating time is 15 min. The reaction product is added into diethyltoluene diamine to be uniformly mixed to obtain a mixed curing agent; ②the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ③bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ④the mixtures obtained in steps ② and ③ are uniformly mixed in a homogenizer under vacuum to obtain the epoxy potting adhesive with high Tg and low modulus after curing.

[0123] In step ①, the components and weight percentage contents are as follows: 2-ethylaniline: 5.66%; N-methyl maleimide resin: 14.15%; diethyltoluene diamine: 80.19%.

[0124] In step ②, the components and weight percentage contents are as follows: mixed curing agent: 13.40%; silica microspheres: 85.28%; silane coupling agent: 1.26%; defoaming agent: 0.03%; leveling agent: 0.03%.

[0125] In step ③, the components and weight percentage contents are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl-p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%; toughening agent: 1.79%.

[0126] In step ④, the molar ratio of active hydrogen and epoxy groups in steps ② and ③ is ensured to be 1.03.

[0127] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, toughening agent, silane coupling agent, defoaming agent and leveling agent used in example 6 are the same as those in example 1.

[0128] Example 7

[0129] The preparation process of the epoxy potting adhesive is as follows: ①2-ethyl aniline and N-cyclohexyl maleimide are mixed and heated to react, the heating temperature is 80℃, and the heating time is 15 min. The reaction product is added into diethyl toluene diamine to be uniformly mixed to obtain a mixed curing agent; ②the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ③bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ④the mixtures obtained in steps ② and ③ are uniformly mixed in a homogenizer under vacuum to obtain the epoxy potting adhesive with high Tg and low modulus after curing.

[0130] In step ①, the components and weight percentage contents are as follows: 2-ethyl aniline: 4.54%; N-cyclohexyl maleimide resin: 13.64%; diethyl toluene diamine: 81.82%.

[0131] In step ②, the components and weight percentage contents are as follows: mixed curing agent: 10.61%; silica microspheres: 88.03%; silane coupling agent KH560: 1.304%; defoaming agent BYK-1799: 0.028%; leveling agent BYK-9076: 0.028%.

[0132] In step ③, the components and weight percentage contents are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl-p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent KH560: 1.22%; defoaming agent BYK-1799: 0.03%; leveling agent BYK-9076: 0.03%; toughening agent: 1.79%.

[0133] In step ④, the molar ratio of active hydrogen to epoxy group in steps ② and ③ is 0.85.

[0134] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, toughening agent, silane coupling agent, defoaming agent and leveling agent used in example 7 are the same as those in example 1.

[0135] Example 8

[0136] The preparation process of the epoxy potting adhesive is as follows: ①2-ethyl aniline and N-cyclohexyl maleimide are mixed and heated to react, the heating temperature is 80℃, and the heating time is 15 min. The reaction product is added into diethyl toluene diamine to be uniformly mixed to obtain a mixed curing agent; ②the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ③bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent are uniformly mixed in a homogenizer to obtain a mixture; ④the mixtures obtained in steps ② and ③ are uniformly mixed in a homogenizer under vacuum to obtain the epoxy potting adhesive with high Tg and low modulus after curing.

[0137] In step ①, the components and weight percentage contents are as follows: 2-ethyl aniline: 4.54%; N-cyclohexyl maleimide resin: 13.64%; diethyl toluene diamine: 81.82%.

[0138] In step ②, the components and weight percentage contents are as follows: mixed curing agent: 13.73%; silica microspheres: 84.96%; silane coupling agent KH560: 1.26%; defoaming agent BYK-1799: 0.025%; leveling agent BYK-9076: 0.025%.

[0139] In step ③, the components and weight percentage contents are as follows: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl-p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent KH560: 1.22%; defoaming agent BYK-1799: 0.03%; leveling agent BYK-9076: 0.03%; toughening agent: 1.79%.

[0140] In step ④, the molar ratio of active hydrogen to epoxy group in steps ② and ③ is 1.1.

[0141] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl-p-aminophenol, toughening agent, silane coupling agent, defoaming agent and leveling agent used in example 8 are the same as those in example 1.

[0142] Comparative example 1

[0143] The preparation process of the potting adhesive is: ①mixing 4'4 methylene bis (2, 6 diethyl aniline) and diethyl toluene diamine uniformly to obtain a mixed curing agent; ②mixing the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent uniformly in a homogenizer to obtain a mixture; ③mixing bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent uniformly in a homogenizer to obtain a mixture; ④mixing the mixtures obtained in steps ② and ③ uniformly in a homogenizer under vacuum to obtain the potting adhesive.

[0144] The components and weight percentage in step ① are: diethyl toluene diamine: 50%; 4'4 methylene bis (2, 6 diethyl aniline): 50%.

[0145] The components and weight percentage in step ② are: mixed curing agent: 11.67%; silica microspheres: 86.98%; silane coupling agent: 1.29%; defoaming agent: 0.03%; leveling agent: 0.03%.

[0146] The components and weight percentage in step ③ are: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%; toughening agent: 1.79%.

[0147] The molar ratio of active hydrogen and epoxy groups in steps ② and ③ should be 0.9.

[0148] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, toughening agent, silane coupling agent, defoaming agent and leveling agent used in Comparative Example 1 are the same as those in Example 1.

[0149] Comparative Example 2

[0150] The preparation process of the potting adhesive is: ①mixing N-benzyl maleimide into diethyl toluene diamine to obtain a mixed curing agent; ②mixing the mixed curing agent, silica microspheres, silane coupling agent, defoaming agent and leveling agent uniformly in a homogenizer to obtain a mixture; ③mixing bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, silica microspheres, silane coupling agent, defoaming agent and leveling agent uniformly in a homogenizer to obtain a mixture; ④mixing the mixtures obtained in steps ② and ③ uniformly in a homogenizer under vacuum to obtain the potting adhesive.

[0151] The components and weight percentage in step ① are: N-benzyl maleimide: 35%; diethyl toluene diamine: 65%.

[0152] Step 2: Each component and weight percentage: mixed curing agent: 16.2%; silica microspheres: 82.53%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%.

[0153] Step 3: Each component and weight percentage: bisphenol A epoxy resin: 4.17%; bisphenol F epoxy resin: 1.19%; trisglycidyl p-aminophenol: 8.94%; silica microspheres: 82.63%; silane coupling agent: 1.22%; defoaming agent: 0.03%; leveling agent: 0.03%; toughening agent: 1.79%.

[0154] Step 4: Ensure that the molar ratio of active hydrogen to epoxy groups in steps 2 and 3 is 0.9.

[0155] The bisphenol A epoxy resin, bisphenol F epoxy resin, trisglycidyl p-aminophenol, toughening agent, silane coupling agent, defoaming agent, and leveling agent used in Comparative Example 2 are the same as in Example 1.

[0156] Figure 1 is the FTIR spectrum of the raw material and the epoxy capping agent of Example 1, the peak at 1604 cm -1 is the stretching vibration peak of C=C bond, the peak at 1697 cm -1 is the stretching vibration peak of C=O, the peak at 3087 cm -1 is the stretching vibration peak of C-H bond on C=C bond. In the FTIR spectrum of the N-cyclohexyl maleimide raw material, the C=C, C=O, and C-H stretching vibration peaks on the carbon-carbon double bond can be observed. After mixing with 2-ethylamine and reacting, the C=C and C-H stretching vibration peaks on the double bond disappear in the product, while the C=O bond still exists, which indicates that an addition reaction occurs between the raw materials, the C=C double bond is opened by the amine group, and the product is an aromatic amine with a secondary amine of formula I, which can be used as a capping agent during curing.

[0157] The product generated by the reaction of the monoamine aromatic amine in Examples 2-8 with maleimide also has a characteristic peak of -NH-, and the product is an aromatic amine with a secondary amine, which can be used as a capping agent.

[0158] Thermodynamic property testing of cured epoxy potting adhesive in each example and comparative example: tested according to GB / T 40396-2021 "Polymer-based composite glass transition temperature test method-dynamic mechanical analysis method".

[0159] The test results are shown in Table 1 below:

[0160] Table 1 Performance test results of examples and comparative examples

[0161] Experiment No. Tg (°C) 175 °C storage modulus (MPa) Example 1 210.13 7813 Example 2 201.13 7505 Example 3 204.33 7403 Example 4 202.15 6215 Example 5 206.85 6524 Example 6 203.5 7003 Example 7 206.24 7307 Example 8 201.21 6314 Comparative Example 1 199.56 11182 Comparative Example 2 189.52 7721

[0162] From the test results of Examples 1-8, Comparative Examples 1 and 2, and Table 1, it can be seen that, compared to Comparative Examples 1 and 2, the samples prepared according to Examples 1-8 have lower high-temperature storage modulus (at 175°C) while maintaining the Tg. This is because the secondary amine in the aromatic amine acts as an end-capping agent to cap the epoxy resin during curing, reducing the crosslinking density; in addition, the capped epoxy resin chain can act as a flexible branch, both of which contribute to the reduction of high-temperature storage modulus. The benzene ring in the aromatic amine can increase the rigidity of the molecular chain, maintaining the Tg.

[0163] Compared to Example 2, Example 1 has a higher content of diethyltoluene diamine, resulting in higher crosslinking density and rigidity of the overall resin after curing, which makes the Tg and high-temperature storage modulus of Example 1 higher. However, the N-cyclohexyl maleimide in Example 1 is more flexible than the N-phenyl maleimide in Example 2, so the high-temperature modulus does not increase significantly.

[0164] Example 3 uses the reaction product of p-propyl aniline and N-benzyl maleimide as an end-capping agent, and the sample also has a lower high-temperature storage modulus while maintaining a high Tg.

[0165] Compared to Example 1, Example 4 uses 4'4 methylene bis(2,6-diethyl aniline) instead of diethyltoluene diamine, and also reduces the content of N-cyclohexyl maleimide, both of which contribute to the reduction of the Tg and high-temperature storage modulus of the sample, but the Tg can still be maintained above 200°C.

[0166] Example 5 uses the reaction product of 2,6-diisopropyl aniline and N-cyclohexyl maleimide as an end-capping agent, and has a relatively lower Tg and high-temperature storage modulus compared to Example 1, which has a lower content of diethyltoluene diamine.

[0167] Example 6 uses the reaction product of 2-ethyl aniline and N-methyl maleimide as an end-capping agent, and the rigidity of N-methyl maleimide is relatively weak, so the high-temperature storage modulus of the final sample is reduced.

[0168] Example 7 has a lower content of active hydrogen compared to Example 1, resulting in a slight reduction in crosslinking density, but the overall sample can still maintain a high Tg and relatively low high-temperature storage modulus.

[0169] Example 8 has an increased content of active hydrogen compared to Example 1, and the amount of active hydrogen exceeds that of the epoxy groups, resulting in a portion of the active hydrogen not being reacted, which slightly reduces the crosslinking density, but the overall sample can still maintain a high Tg and relatively low high-temperature storage modulus.

[0170] Comparative Example 1 did not use a capping agent, only diethyltoluene diamine and 2,6-diisopropylaniline were used as curing agents, the sample had high crosslinking density and rigidity, and the final high temperature storage modulus was large, which was not conducive to use at high temperature.

[0171] Comparative Example 2 did not use a capping agent, and N-benzyl maleimide was used to reduce the modulus, the Tg of the sample was low, which was not conducive to use at high temperature.

[0172] In the description of the present specification, the description referring to the terms "some embodiments", "other embodiments", and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments are contained in at least one embodiment of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0173] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. An epoxy potting compound, characterized in that: The invention comprises a first composition and a second composition, wherein the first composition comprises a mixed curing agent, silica microspheres and a silane coupling agent, the mixed curing agent comprises a capping agent and a polyamino aromatic amine, and the capping agent comprises a compound represented by Formula 1. wherein R1 to R5 are each independently hydrogen or a C1 to C5 substituted or unsubstituted, branched or linear alkyl group; R6 is a C6 to C 10 Substituted or unsubstituted aryl, C3~C8 cycloalkyl, C1~C 12 a substituted or unsubstituted, branched or linear alkyl group; The second composition includes epoxy resin, silica microspheres and a silane coupling agent.

2. The epoxy potting compound according to claim 1, wherein: The molar ratio of active hydrogen in the first composition to epoxy groups in the second composition is 0.85 to 1.

1.

3. The epoxy potting compound according to claim 2, wherein: The molar ratio of active hydrogen in the first composition to epoxy groups in the second composition is 0.9-1.

4. The epoxy potting compound according to any one of claims 1 to 3, characterized in that: R6 is cyclohexyl, phenyl, benzyl or methyl.

5. The epoxy potting compound according to any one of claims 1 to 4, characterized in that: The end-capping agent satisfies one of the following conditions: R1 to R5 are hydrogen; R1 is ethyl, R2 to R5 are hydrogen; R1 is methylmercapto, R2 to R5 are hydrogen; R3 is ethyl, R1, R2, R4, and R5 are hydrogen; R1 and R5 are isopropyl, R2, R3, and R4 are hydrogen; R3 is propyl, R1, R2, R4, and R5 are hydrogen; R1 and R5 are ethyl groups, and R2, R3 and R4 are hydrogen atoms.

6. The epoxy potting compound according to any one of claims 1 to 5, characterized in that: The mixed curing agent comprises a capping agent with a weight percentage of 16.3% to 24% and a polyamino aromatic amine with a weight percentage of 76% to 82%; And / or, the polyamino aromatic amine includes one or more of diethyltoluenediamine and 4'4-methylenebis(2,6-diethylaniline).

7. The epoxy potting compound according to any one of claims 1 to 6, characterized in that: At least one of the following conditions is met: The silica microspheres in the first composition and the silica microspheres in the second composition each independently have a Dv50 particle size of 1 μm to 100 μm; The silane coupling agent in the first composition and the silane coupling agent in the second composition each independently include one or more of KH560 silane coupling agent, KH570 silane coupling agent and KH590 silane coupling agent; The epoxy resin includes one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, triglycidyl ether p-aminophenol, and novolac epoxy resin.

8. The epoxy potting compound according to any one of claims 1 to 7, characterized in that: The first composition further includes a first auxiliary agent, and optionally, the first auxiliary agent includes a defoaming agent and a leveling agent; The second composition further includes a second auxiliary agent. Optionally, the second auxiliary agent includes a toughening agent, a defoaming agent and a leveling agent.

9. The epoxy potting compound according to claim 8, characterized in that: The first composition comprises: A mixed curing agent with a weight percentage of 11% to 21.5%; Silicon oxide microspheres with a weight percentage of 77% to 87.55%; A silane coupling agent having a weight percentage of 1.15% to 1.35%; The weight percentage content is 0.01% to 0.1% of the first auxiliary agent; The second composition comprises: 12.7% to 15% by weight of epoxy resin; 81% to 84% by weight of silicon oxide microspheres; A silane coupling agent having a weight percentage of 1.2% to 1.4%; The weight percentage of the second auxiliary agent is 1.54% to 1.98%.

10. The epoxy potting compound according to claim 8, wherein: The first composition comprises: A mixed curing agent with a weight percentage of 11% to 21.5%; Silicon oxide microspheres with a weight percentage of 77% to 87.55%; A silane coupling agent having a weight percentage of 1.15% to 1.35%; A defoaming agent having a weight percentage of 0.005% to 0.05%; A leveling agent with a weight percentage of 0.005% to 0.05%; The second composition comprises: 12.7% to 15% by weight of epoxy resin; 81% to 84% by weight of silicon oxide microspheres; A silane coupling agent having a weight percentage of 1.2% to 1.4%; A defoaming agent having a weight percentage of 0.02% to 0.04%; A leveling agent with a weight percentage of 0.02% to 0.04%; The weight percentage of the toughening agent is 1.5% to 1.9%.

11. A method for preparing the epoxy potting compound according to any one of claims 1 to 10, characterized in that: include: A monoamino aromatic amine and maleimide are mixed and heated to react to obtain a capping agent, wherein the monoamino aromatic amine includes a compound shown in Formula 2, and the maleimide includes a compound shown in Formula 3. wherein R1 to R5 are each independently hydrogen or a C1 to C5 substituted or unsubstituted, branched or linear alkyl group; R6 is a C6 to C 10 Substituted or unsubstituted aryl, C3~C8 cycloalkyl, C1~C 12 a substituted or unsubstituted, branched or linear alkyl group; mixing the end-capping agent with polyamino aromatic amine, silica microspheres and a silane coupling agent to obtain a first composition; The epoxy resin, silica microspheres and silane coupling agent are mixed to obtain a second composition.

12. The method according to claim 11, characterized in that The temperature of the heating reaction is 60° C. to 85° C., and / or the time of the heating reaction is 10 min to 30 min.

13. The method according to claim 11 or 12, characterized in that At least one of the following conditions is met: The monoamino aromatic amine includes one or more of 2-ethylaniline, 2-methylmercaptoaniline, 4-ethylaniline, 2,6-diisopropylaniline, p-propylaniline, and 2,6-diethylaniline; The maleimide includes one or more of N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide, and N-methylmaleimide.

14. The method according to any one of claims 11 to 13, characterized in that The end-capping agent is mixed with the polyamino aromatic amine, and the obtained mixture is then mixed with silica microspheres, a silane coupling agent and a first auxiliary agent to obtain the first composition; The epoxy resin, silicon oxide microspheres, silane coupling agent and second auxiliary agent are mixed to obtain the second composition.

15. Use of the epoxy potting compound according to any one of claims 1 to 10 in power devices.

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