An epoxy resin-based composite material and a preparation method and application thereof

Abstract

The application discloses an epoxy resin-based composite material and a preparation method and application thereof, and relates to the technical field of composite materials, in particular to an epoxy resin-based composite material, which comprises an epoxy resin precursor and heat-conducting insulating particles; wherein the epoxy resin precursor comprises an epoxy resin, a curing agent and an accelerator; the heat-conducting insulating particles are a mixture of non-metallic oxides and boron nitride, and the diameters of the non-metallic oxides and the boron nitride are different. The epoxy resin-based composite material has the advantages of high heat conductivity, low dielectric loss, simple processing technology, excellent high-frequency electrical insulation performance and the like; and the preparation process is simple, easy to operate, and the raw materials are easy to obtain, so that the energy consumption is low, the preparation cost is low, and the epoxy resin-based composite material has good economic benefits and market application potential.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology. Specifically, this invention relates to an epoxy resin-based composite material, its preparation method, and its application. Background Technology

[0002] In recent years, power electronic devices, primarily solid-state transformers, have been widely used in renewable energy grids. Their development towards higher voltage, higher frequency, and higher power density has led to a sharp increase in heat generation per unit volume, accelerating the failure of encapsulation insulation materials and significantly reducing equipment reliability. Epoxy resin, due to its excellent insulation properties, processing performance, and low cost, is commonly used as the encapsulation insulation material for solid-state transformers. However, epoxy resin has a low thermal conductivity of only about 0.2 W / (m·K), poor thermal conductivity, and poor electrical insulation performance at high frequencies, necessitating improved thermal conductivity for electronic equipment applications. Typically, this is achieved by adding high thermal conductivity fillers to epoxy resin. However, the addition of large amounts of high thermal conductivity fillers is usually accompanied by insulation defects and a significant increase in viscosity, affecting transformer service life and casting manufacturing processes. Therefore, preparing suitable high-frequency insulating epoxy composite materials while ensuring industrial production remains a significant challenge.

[0003] To improve the thermal conductivity and electrical insulation performance of epoxy resins at high frequencies, insulating fillers with high thermal conductivity are typically added to the epoxy resin matrix. For example, Bian et al., in "The synergistic effects of the micro-BN and nano-Al2O3 in micro-nano composites on enhancing the thermalconductivity for insulating epoxy resin" (Composites Science and Technology, 2018, 168, 420-428), used dopamine to modify 10 μm boron nitride and γ-aminopropyltriethoxysilane to modify 30 nm Al2O3. With a BN content of 22.5 wt% and an Al2O3 content of 7.5 wt%, the thermal conductivity was increased to 1.182 W / (m·K). The dielectric loss increased significantly with increasing filler content, and the breakdown time at high frequencies increased with increasing boron nitride content. Meanwhile, in their paper "Hydroxyl-group decreased dielectric loss coupled with 3D-BNnetwork enhanced high thermal conductivity epoxy composite for high voltage-high frequency conditions" (Composites Science and Technology, 2023, 234, 109934), Yao et al. induced boron nitride to self-assemble around the bubbles generated by the decomposition of ammonium bicarbonate, constructing a three-dimensional thermally conductive network skeleton using an ice template method. The composite material was then prepared by vacuum-assisted impregnation with epoxy resin. With a boron nitride content of 31.1 wt%, the thermal conductivity increased by 1.62 W / (m·K), and its dielectric loss was also reduced compared to epoxy resin, which is beneficial for reducing temperature rise at high frequencies and extending insulation life. However, the high price of boron nitride and the limited size of the skeleton prepared by the ice template method are not conducive to large-scale industrial production; further improvements are needed in its dielectric and electrical insulation properties at high frequencies.

[0004] Therefore, for the packaging insulation materials of high-frequency and high-voltage equipment, the pursuit of high thermal conductivity, low dielectric loss, and electrical insulation performance of epoxy resin-based materials, while also having a processing technology that can be industrially applied, has become an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an epoxy resin-based composite material with excellent thermal conductivity, dielectric properties and electrical insulation properties.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, embodiments of the present invention provide an epoxy resin-based composite material comprising the following components:

[0008] An epoxy resin precursor, wherein the epoxy resin precursor comprises epoxy resin, a curing agent, and an accelerator;

[0009] Thermally conductive insulating particles, wherein the thermally conductive insulating particles are a mixture of non-metallic oxides and boron nitride, and the non-metallic oxides and boron nitrides have different diameters.

[0010] This invention provides an epoxy resin-based composite material prepared by using epoxy resin as the polymer matrix and thermally conductive and insulating particles composed of non-metallic oxides and boron nitride of different diameters as the dispersed phase. This material has advantages such as low cost, high thermal conductivity, low dielectric loss, simple processing technology, and excellent high-frequency electrical insulation performance.

[0011] In some embodiments, the non-metallic oxide is either silicon dioxide or aluminum oxide;

[0012] Preferably, the silicon dioxide is spherical with a diameter of 5 μm; the aluminum oxide is spherical with a diameter of 5 μm.

[0013] In some embodiments, the boron nitride is in the form of a sheet with an in-plane diameter of 25 μm.

[0014] In some embodiments, the mass ratio of the non-metallic oxide to the boron nitride in the thermally conductive insulating particles is (2-4):1.

[0015] In some embodiments, the mass ratio of the epoxy resin precursor to the thermally conductive insulating particles is (0.8–2):1.

[0016] In some embodiments, the mass ratio of the epoxy resin, the curing agent and the accelerator in the epoxy resin precursor is 100:(80-90):(1-2).

[0017] Secondly, embodiments of the present invention also provide a method for preparing epoxy resin-based composite materials as described in the first aspect, comprising the following steps:

[0018] S1, epoxy resin, curing agent and accelerator are stirred and mixed to obtain epoxy resin precursor;

[0019] S2, add thermally conductive and insulating particles to the epoxy resin precursor, stir and mix to obtain an epoxy resin-based composite material suspension.

[0020] S3, the epoxy resin-based composite material suspension is subjected to gradient curing to obtain the epoxy resin-based composite material.

[0021] The preparation method in this invention is simple and easy to implement, uses readily available raw materials, has low energy consumption, and low preparation cost. It solves the problems of complex preparation process and high cost when epoxy resin is used as a material in high voltage external insulation and power electronic equipment. Moreover, the epoxy resin-based composite material obtained has excellent thermal conductivity, dielectric properties, and electrical insulation properties.

[0022] In some embodiments, in steps S1 and / or S2, the stirring and mixing are carried out in a vacuum environment, the stirring and mixing time is 30 to 60 minutes, and the stirring speed is 1500 to 2000 r / min.

[0023] In some embodiments, in step S3, the gradient curing process is as follows: the epoxy resin-based composite material suspension is first pre-cured at 80-100°C for 1-3 hours, and then cured at 120-150°C for 5-10 hours.

[0024] Thirdly, embodiments of the present invention also propose the application of epoxy resin-based composite materials as described in the first aspect in the preparation of encapsulation insulating materials. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the preparation method of epoxy resin-based composite material according to an embodiment of the present invention.

[0026] Figure 2 SEM image of the epoxy resin-based composite material obtained in Example 1 of this invention.

[0027] Figure 3 The thermal conductivity is given by the epoxy resin-based composite materials prepared in Examples 1 and 2 and Comparative Example 1 of the present invention.

[0028] Figure 4 The graph shows the relationship between dielectric loss and frequency for the epoxy resin-based composite materials prepared in Examples 1 and 2 and Comparative Examples 1 and 2 of this invention.

[0029] Figure 5 The breakdown time of the epoxy resin-based composite materials prepared in Examples 1 and 2 and Comparative Examples 1 and 2 of the present invention under high frequency and high voltage is given. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0031] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0032] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0033] In this article, the words “contain” and “include” and their various variations mean that other elements or wholes may be included but not specifically described.

[0034] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone.

[0035] In a first aspect, embodiments of the present invention provide an epoxy resin-based composite material, comprising an epoxy resin precursor and thermally conductive insulating particles; wherein the epoxy resin precursor comprises epoxy resin, a curing agent, and an accelerator; the thermally conductive insulating particles are a mixture of non-metallic oxides and boron nitride, and the non-metallic oxides and boron nitride have different diameters.

[0036] This invention provides an epoxy resin-based composite material prepared by combining an epoxy resin precursor with thermally conductive and insulating particles. This not only improves the thermal conductivity of the epoxy resin-based composite material but also reduces its dielectric loss at high frequencies and enhances its insulation performance. Furthermore, the epoxy resin-based composite material in this invention requires no special reagents, is widely available and inexpensive, and poses minimal harm to the environment and human health, making it highly practical and valuable for application.

[0037] In some embodiments, the non-metallic oxide is either silicon dioxide or aluminum oxide;

[0038] Preferably, the silicon dioxide is spherical with a diameter of 5 μm; the aluminum oxide is spherical with a diameter of 5 μm.

[0039] In some embodiments, boron nitride is in the form of a sheet with an in-plane diameter of 25 μm.

[0040] It should be noted that the non-metallic oxides (silicon dioxide or aluminum oxide) and boron nitride used in the embodiments of the present invention have not undergone any modification and are directly purchased.

[0041] Using a mixture of silica / alumina and boron nitride with different diameters as a thermally conductive and insulating filler helps to reduce the viscosity of epoxy resin-based composites, improve their electrical insulation properties, reduce the production cost of epoxy resin-based composites, effectively utilize their thermal conductivity, and improve their dielectric properties.

[0042] In some embodiments, the mass ratio of non-metallic oxide to boron nitride in the thermally conductive insulating particles is (2-4):1, for example, it can be 2:1, 2.5:1, 2.8:1, 3:1, 3.2:1 or 4:1, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The inventors have discovered that flake-shaped boron nitride has higher thermal conductivity and a larger specific surface area, which easily increases the viscosity of epoxy resin-based composite materials, leading to increased processing difficulty and defects. Spherical silica / alumina, on the other hand, is inexpensive, has higher thermal conductivity than epoxy resin, and exhibits stable and excellent electrical insulation properties. Therefore, in this embodiment of the invention, the two are compounded as thermally conductive insulating particles, and the mass ratio of silica / alumina to boron nitride is controlled at (2-4):1, which can improve the thermal conductivity and electrical insulation properties of epoxy resin-based composite materials and reduce processing difficulty and production costs.

[0043] In some embodiments, the mass ratio of epoxy resin precursor to thermally conductive insulating particles is (0.8 to 2):1, for example, it can be 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0044] In some embodiments, the mass ratio of epoxy resin, curing agent and accelerator in the epoxy resin precursor is 100:(80-90):(1-2), for example, it can be 100:80:1, 100:80:1.5, 100:80:2, 100:85:1, 100:90:1 or 100:90:2, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0045] It should be noted that the epoxy resin used in the embodiments of the present invention is a thermosetting resin, specifically referring to a class of polymers containing two or more epoxy groups in their molecules, which are condensation products of epichlorohydrin and bisphenol A or polyols. Due to the chemical reactivity of epoxy groups, various compounds containing active hydrogen can be used to open their rings, thereby curing and crosslinking to form a network structure, thus obtaining the epoxy resin precursor.

[0046] Furthermore, the epoxy resin used in the embodiments of the present invention is not particularly limited, and those skilled in the art can select it according to actual needs. For example, the epoxy resin can be one or a combination of two or more of the following: bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol S type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, etc., which are liquid at temperatures below 40°C. However, considering the performance of epoxy resin-based composite materials, the embodiments of the present invention preferably use bisphenol A type epoxy resin that is liquid at temperatures below 40°C.

[0047] And / or, the curing agent, which is not particularly limited in the embodiments of the present invention, can be some curing agents commonly used in the art. For example, one or a combination of two or more of diaminodiphenyl sulfone, 4,4'-dihydroxybiphenyl, 4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, or methylhexahydrophthalic anhydride. In the embodiments of the present invention, methylhexahydrophthalic anhydride in a liquid state below 40°C is preferred.

[0048] And / or, the accelerator, which is not particularly limited in the embodiments of the present invention, can be some commonly used accelerators in the art, such as tertiary amines and their salts, or imidazole compounds, etc. The tertiary amines and their salts can be 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, etc.; the imidazole compounds can be 2-methylimidazole, N-vinylimidazole, etc. In the embodiments of the present invention, 2,4,6-tris(dimethylaminomethyl)phenol in a liquid state below 40°C is preferred.

[0049] Secondly, such as Figure 1 As shown, this embodiment of the invention also proposes a method for preparing the epoxy resin-based composite material as described in the first aspect, comprising the following steps:

[0050] S1, epoxy resin, curing agent and accelerator are stirred and mixed to obtain epoxy resin precursor;

[0051] S2, add thermally conductive and insulating particles to the epoxy resin precursor, stir and mix to obtain an epoxy resin-based composite material suspension.

[0052] S3, the epoxy resin-based composite material suspension is subjected to gradient curing to obtain the epoxy resin-based composite material.

[0053] The preparation method of the epoxy resin-based composite material in the embodiments of the present invention is simple, easy to implement, has a reasonable raw material formula, is easy to promote, and has strong practicality. It can improve the thermal conductivity and reduce the dielectric loss of the epoxy resin-based composite material, and at the same time improve the high-frequency electrical insulation performance of the epoxy resin-based composite material.

[0054] In some embodiments, in steps S1 and / or S2, the stirring and mixing are carried out in a vacuum environment, and the stirring and mixing time is 30 to 60 minutes, for example, 30 minutes, 40 minutes, 45 minutes, 50 minutes or 60 minutes, but not limited to the listed values, and other unlisted values ​​within this range are also applicable; the stirring speed is 1500 to 2000 r / min, for example, 1500 r / min, 1750 r / min, 1800 r / min or 2000 r / min, but not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0055] In some embodiments, in step S3, the gradient curing process involves pre-curing the epoxy resin-based composite material suspension at 80–100°C (non-limiting examples: 80°C, 85°C, 90°C, 100°C, etc.) for 1–3 hours (non-limiting examples: 1 hour, 1.5 hours, 1.8 hours, 2 hours, 2.5 hours, 3 hours, etc.), and then curing it at 120–150°C (non-limiting examples: 120°C, 125°C, 130°C, 140°C, 150°C, etc.) for 5–10 hours (non-limiting examples: 5 hours, 6 hours, 7.5 hours, 8 hours, 9 hours, 10 hours, etc.). The inventors have found that by employing gradient curing, the epoxy resin can be cured more thoroughly, and the cross-linking reaction can be carried out more completely, which is beneficial for improving the insulation performance of the epoxy resin-based composite material.

[0056] The epoxy resin-based composite material in this embodiment of the invention can be cured at a lower temperature, thereby reducing production energy consumption and saving production costs.

[0057] Thirdly, embodiments of the present invention also propose the application of epoxy resin-based composite materials as described in the first aspect in the preparation of encapsulation insulating materials.

[0058] The following are non-limiting embodiments and comparative examples of the present invention. It should be noted that the schemes in the comparative examples are not prior art, but are only set up for comparison with the schemes in the embodiments, and are not intended to limit the present invention. Unless otherwise stated, all raw materials used in the embodiments and comparative examples are conventional commercially available products, or can be prepared by known methods.

[0059] Example 1

[0060] This embodiment provides an epoxy resin-based composite material comprising the following components: bisphenol A type epoxy resin, methyl hexahydrophthalic anhydride, 2,4,6-tris(dimethylaminomethyl)phenol, 5μm spherical alumina, and 25μm sheet-like boron nitride.

[0061] The preparation method of this epoxy resin-based composite material includes the following steps:

[0062] S1, 10.0g of bisphenol A type epoxy resin, 8g of curing agent methyl hexahydrophthalic anhydride and 0.1g of accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed under vacuum at room temperature at a stirring speed of 1500r / min for 30min to obtain epoxy resin precursor;

[0063] S2, add 13.5g of 5μm spherical alumina and 4.5g of 25μm flake boron nitride to the epoxy resin precursor obtained in step S1, and mix under vacuum at 1500r / min for 30min at room temperature to obtain an epoxy resin-based composite material suspension.

[0064] S3. Place the epoxy resin-based composite material suspension obtained in step S2 in a vacuum drying oven and remove air bubbles under vacuum at 40°C for 30 minutes. Then, pre-cure the epoxy resin-based composite material suspension at 100°C for 1 hour and then cure it at 120°C for 7 hours. After demolding, the epoxy resin-based composite material can be obtained.

[0065] like Figure 2 The image shown is a SEM image of the epoxy resin-based composite material prepared in this embodiment. As can be seen from the image, spherical alumina and plate-like boron nitride are loaded in the epoxy resin precursor. At the same time, the large-diameter plate-like boron nitride increases the contact area between the boron nitride and the small-diameter spherical alumina particles, which not only meets the requirements of low viscosity processing but also increases the thermal conductivity pathway within the epoxy resin, thereby improving the thermal conductivity of the epoxy resin-based composite material.

[0066] Example 2

[0067] This embodiment provides an epoxy resin-based composite material comprising the following components: bisphenol A type epoxy resin, methyl hexahydrophthalic anhydride, 2,4,6-tris(dimethylaminomethyl)phenol, 5μm spherical silica, and 25μm sheet-like boron nitride.

[0068] The preparation method of this epoxy resin-based composite material includes the following steps:

[0069] S1, 10.0g of bisphenol A type epoxy resin, 8g of curing agent methyl hexahydrophthalic anhydride and 0.1g of accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed under vacuum at room temperature at a stirring speed of 1500r / min for 30min to obtain epoxy resin precursor;

[0070] S2, add 13.5g of 5μm spherical silica and 4.5g of 25μm sheet boron nitride to the epoxy resin precursor obtained in step S1, and mix under vacuum at a stirring speed of 1500r / min for 30min at room temperature to obtain an epoxy resin-based composite material suspension.

[0071] S3. Place the epoxy resin-based composite material suspension obtained in step S2 in a vacuum drying oven and remove air bubbles under vacuum at 40°C for 30 minutes. Then, pre-cure the epoxy resin-based composite material suspension at 100°C for 1 hour and then cure it at 120°C for 7 hours. After demolding, the epoxy resin-based composite material can be obtained.

[0072] Comparative Example 1

[0073] This comparative example provides an epoxy resin material comprising the following components: bisphenol A type epoxy resin, methyl hexahydrophthalic anhydride, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0074] The preparation method of this epoxy resin material includes the following steps:

[0075] S1, 10.0g of bisphenol A type epoxy resin, 8g of curing agent methyl hexahydrophthalic anhydride and 0.1g of accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed under vacuum at room temperature at a stirring speed of 1500r / min for 30min to obtain epoxy resin precursor;

[0076] S2, the epoxy resin precursor obtained in step S1 is placed in a vacuum drying oven and vacuum-dried at 40°C for 30 minutes to remove air bubbles. Then, the epoxy resin precursor is pre-cured at 100°C for 1 hour and then cured at 120°C for 7 hours. After demolding, the epoxy resin material can be obtained.

[0077] Comparative Example 2

[0078] This comparative example provides an epoxy resin-based composite material comprising the following components: bisphenol A type epoxy resin, methyl hexahydrophthalic anhydride, 2,4,6-tris(dimethylaminomethyl)phenol, 40 μm spherical alumina, and 25 μm sheet-like boron nitride.

[0079] The preparation method of this epoxy resin-based composite material includes the following steps:

[0080] S1, 10.0g of bisphenol A type epoxy resin, 8g of curing agent methyl hexahydrophthalic anhydride and 0.1g of accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed under vacuum at room temperature at a stirring speed of 1500r / min for 30min to obtain epoxy resin precursor;

[0081] S2, add 13.5g of 40μm spherical alumina and 4.5g of 25μm lamellar boron nitride to the epoxy resin precursor obtained in step S1, and mix under vacuum at 1500r / min for 30min at room temperature to obtain an epoxy resin-based composite material suspension.

[0082] S3. Place the epoxy resin-based composite material suspension obtained in step S2 in a vacuum drying oven and remove air bubbles under vacuum at 40°C for 30 minutes. Then, pre-cure the epoxy resin-based composite material suspension at 100°C for 1 hour and then cure it at 120°C for 7 hours. After demolding, the epoxy resin-based composite material can be obtained.

[0083] The thermal conductivity of the epoxy resin products prepared in Examples 1 and 2 and Comparative Example 1 of this invention was tested using the laser flare method, and the results are as follows: Figure 3 As shown. From Figure 3 As can be seen, compared to the epoxy resin product prepared in Comparative Example 1, which has a thermal conductivity of only 0.229 W / (m·K), the epoxy resin-based composite material prepared in Example 1 of this invention has a thermal conductivity as high as 1.009 W / (m·K), and the epoxy resin-based composite material prepared in Example 2 has a thermal conductivity of 0.732 W / (m·K), exhibiting higher thermal conductivity.

[0084] The dielectric properties of the epoxy resin products prepared in Examples 1 and 2 and Comparative Examples 1 and 2 of this invention were tested, and the relationship between dielectric loss and frequency is shown in the figure below. Figure 4 As shown. From Figure 4 As can be seen, at 20kHz, the dielectric losses of the epoxy resin products prepared in Comparative Examples 1 and 2 are 0.037 and 0.032, respectively. The dielectric loss of the epoxy resin-based composite material prepared in Example 1 of this invention is lower than that of Comparative Examples 1 and 2, at 0.031. The dielectric loss of the epoxy resin-based composite material prepared in Example 2 is even more significantly lower than that of Comparative Examples 1 and 2, at 0.024, indicating that the epoxy resin-based composite material prepared in the embodiments of this invention has a lower dielectric loss.

[0085] The breakdown time of the epoxy resin products prepared in Examples 1 and 2 and Comparative Examples 1 and 2 of this invention under high frequency and high voltage was tested, and the results are as follows: Figure 5 As shown. By Figure 5It can be seen that the epoxy resin products prepared in Comparative Examples 1 and 2 have breakdown times of only 16s and 13s under high frequency and high voltage, respectively, while the epoxy resin-based composite material prepared in Example 1 of this invention has a breakdown time of 24s under high frequency and high voltage, and the epoxy resin-based composite material prepared in Example 2 has a breakdown time of 45s under high frequency and high voltage, all of which show superior electrical insulation performance.

[0086] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0087] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An epoxy resin-based composite material, characterized in that, It includes the following components: An epoxy resin precursor, wherein the epoxy resin precursor comprises epoxy resin, a curing agent, and an accelerator; The thermally conductive insulating particles are a mixture of non-metallic oxide and boron nitride; wherein the non-metallic oxide is silicon dioxide; the silicon dioxide is spherical with a diameter of 5µm; the boron nitride is plate-shaped with an in-plane diameter of 25µm; and the mass ratio of the non-metallic oxide to the boron nitride in the thermally conductive insulating particles is (2-4):1; the mass ratio of the epoxy resin precursor to the thermally conductive insulating particles is (0.8-2):

1.

2. The epoxy resin-based composite material according to claim 1, characterized in that, In the epoxy resin precursor, the mass ratio of the epoxy resin, the curing agent and the accelerator is 100:(80-90):(1-2).

3. A method for preparing an epoxy resin-based composite material as described in claim 1 or 2, characterized in that, Includes the following steps: S1, epoxy resin, curing agent and accelerator are stirred and mixed to obtain epoxy resin precursor; S2, add thermally conductive and insulating particles to the epoxy resin precursor, stir and mix to obtain an epoxy resin-based composite material suspension. S3, the epoxy resin-based composite material suspension is subjected to gradient curing to obtain the epoxy resin-based composite material.

4. The method for preparing the epoxy resin-based composite material according to claim 3, characterized in that, In steps S1 and / or S2, the stirring and mixing are carried out in a vacuum environment, the stirring and mixing time is 30 to 60 minutes, and the stirring speed is 1500 to 2000 r / min.

5. The method for preparing the epoxy resin-based composite material according to claim 3, characterized in that, In step S3, the gradient curing process is as follows: the epoxy resin-based composite material suspension is first pre-cured at 80-100℃ for 1-3 hours, and then cured at 120-150℃ for 5-10 hours.

6. The application of an epoxy resin-based composite material as described in claim 1 or 2 in the preparation of encapsulating insulating materials.

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