An epoxy resin composite material with excellent electrical performance and a preparation method and application thereof

Abstract

The application discloses an epoxy resin composite material with superior electrical performance and a preparation method and application thereof, and relates to the field of organic materials. The epoxy resin composite material comprises epoxy resin, a curing agent and silicon powder in a mass ratio of 1:1:3, the epoxy resin is one or more of epoxy resins in HE-8329, EP-1511A and TH-909 brands, the curing agent is one or more of curing agents in HH-8329, EP-1511B and TH-909 brands, and the curing process of the epoxy resin composite material is as follows: vacuumizing for 2h-5h and then curing. The added epoxy resin, the curing agent and the silicon powder component and the content can improve the electrical performance and the heat conduction performance of the epoxy resin composite material as a whole, the comprehensive performance is superior, the sample is vacuumized in the sample preparation process, the defects such as bubbles in the sample can be effectively improved, and therefore the electrical performance and the heat conduction performance are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic materials, in particular to an epoxy resin composite material with superior electrical performance and a preparation method and application thereof. BACKGROUND

[0002] Epoxy resin is a macromolecular polymer, which is a thermosetting resin. Epoxy resin is widely used in the electrical industry, rail transit, new energy and other fields due to its excellent mechanical properties, electrical performance and low cost. Epoxy resin is mainly cured by epoxy resin, curing agent, additive and filler in a certain proportion. Silicon powder (filler) is one of the important components of epoxy resin, which is mainly used to reduce shrinkage, reduce cost and improve performance.

[0003] The existing epoxy resin composite material has the problems of insufficient electrical performance or poor thermal conductivity, and the overall comprehensive performance is insufficient, which limits the application field of the material. SUMMARY

[0004] The present application provides an epoxy resin composite material with superior electrical performance and a preparation method and application thereof, so as to provide an epoxy resin composite material with superior electrical performance and thermal conductivity.

[0005] In order to solve the above technical problems, one of the purposes of the present application is to provide an epoxy resin composite material with superior electrical performance, which comprises epoxy resin, curing agent and silicon powder with a mass ratio of 1:1:3. The epoxy resin is one or more of epoxy resins with HE-8329, EP-1511A and TH-909 brand. The curing agent is one or more of curing agents with HH-8329, EP-1511B and TH-909 brand. The curing process of the epoxy resin composite material is as follows: vacuumizing for 2h-5h and then curing.

[0006] By adopting the above scheme, the electrical performance and thermal conductivity of the epoxy resin composite material can be improved as a whole by adding the components and contents of epoxy resin, curing agent and silicon powder. The comprehensive performance is superior. The sample preparation process is vacuumized, which can effectively improve the defects such as bubbles in the sample, so as to improve the electrical performance and thermal conductivity.

[0007] As a preferred scheme, the curing temperature in the curing process is 60℃-150℃, and the curing time is 10h-15h.

[0008] As a preferred scheme, the epoxy resin is an epoxy resin with HE-8329 brand, and the curing agent is a curing agent with HH-8329 brand. The curing process is as follows: vacuumizing for 2h-5h and then curing at a temperature of 135℃-145℃ for 11h-13h.

[0009] As a preferred solution, the epoxy resin is the epoxy resin in EP-1511A brand, the curing agent is the curing agent in EP-1511A brand, and the curing process is: after vacuumizing for 2-5 hours, curing at 55-65 DEG C for 1.5-2.5 hours, curing at 85-95 DEG C for 2.5-3.5 hours, curing at 125-135 DEG C for 4.5-5.5 hours, and curing at 145-155 DEG C for 1.5-2.5 hours.

[0010] As a preferred solution, the epoxy resin is the epoxy resin in TH-909 brand, the curing agent is the curing agent in TH-909 brand, and the curing process is: after vacuumizing for 2-5 hours, curing at 85-95 DEG C for 3.5-4.5 hours, curing at 105-115 DEG C for 2.5-3.5 hours, and curing at 125-135 DEG C for 5.5-6.5 hours.

[0011] By using the above solution, since the content of the silicon micro powder is high, the fluidity of the system may decrease, the curing difficulty is reduced by using multi-level temperature rising reaction in the curing process, and thus the electrical performance and the thermal conductivity of the epoxy resin composite material are improved as a whole.

[0012] As a preferred solution, the mesh number of the silicon micro powder is 300-400 mesh.

[0013] As a preferred solution, the vacuumizing time in the curing process is 2-3 hours.

[0014] In order to solve the above technical problem, a second object of the present application provides a preparation method of an epoxy resin composite material with superior electrical performance, which comprises the following steps: mixing an epoxy resin and a curing agent according to a proportion, adding silicon micro powder, stirring uniformly, vacuumizing, and then curing to obtain an epoxy resin composite material.

[0015] In order to solve the above technical problem, a third object of the present application provides an application of an epoxy resin composite material with superior electrical performance in the fields of electric power, energy, high-speed rail and manufacturing industry.

[0016] Compared with the prior art, the embodiment of the present application has the following beneficial effects:

[0017] 1. The added epoxy resin, curing agent and silicon micro powder components and contents can improve the electrical performance and thermal conductivity of the epoxy resin composite material as a whole, and the comprehensive performance is superior.

[0018] 2. Due to the high content of the silicon powder in the application, the fluidity of the system may decrease, and the curing difficulty is reduced by using multi-level temperature rising reaction during the curing process, thereby improving the electrical performance and thermal conductivity of the epoxy resin composite as a whole. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 : Photos of samples after the electrothermal aging test of Example 1 and Comparative Examples 1-2 of the application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the application will be described clearly and completely in the embodiments of the application combined with the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0021] Table 1-Source and model of raw materials in the embodiments and comparative examples of the application

[0022]

[0023]

[0024] Example 1-6

[0025] An epoxy resin composite material with superior electrical performance, the components and contents of which are shown in Table 2 below, includes epoxy resin, silicon powder and curing agent, the epoxy resin includes epoxy resin B, D or E, the curing agent includes curing agent B, D or E, and the silicon powder has a mesh size of 400 mesh; the preparation method is as follows: the epoxy resin and the curing agent are mixed in a certain proportion, then the silicon powder is added, and after stirring uniformly, vacuum is extracted for 2-3 h, and then curing is performed according to different curing processes to obtain the epoxy resin composite material.

[0026] Table 2-Components, contents and process parameters of the epoxy resin composite material in Examples 1-6 of the application

[0027]

[0028]

[0029] Comparative Example 1

[0030] An epoxy resin composite material with superior electrical performance, the preparation method of which has the same steps and reagents and process parameters as those of Example 1, and the difference lies in that the content of the silicon powder is 20 kg.

[0031] Comparative Example 2

[0032] An epoxy resin composite material with superior electrical performance, wherein the preparation method, each step and reagent and process parameter used in each step are the same as those of Example 1, except that the content of the silicon micro powder is 10 kg.

[0033] Comparative Example 3

[0034] An epoxy resin composite material with superior electrical performance, wherein the preparation method, each step and reagent and process parameter used in each step are the same as those of Example 1, except that the epoxy resin B is replaced by epoxy resin A, the curing agent B is replaced by curing agent A, and the curing process is (120℃, 4h) + (140℃, 8h).

[0035] Comparative Example 4

[0036] An epoxy resin composite material with superior electrical performance, wherein the preparation method, each step and reagent and process parameter used in each step are the same as those of Example 1, except that the epoxy resin B is replaced by epoxy resin A, and the curing agent B is replaced by curing agent A.

[0037] Comparative Example 5

[0038] An epoxy resin composite material with superior electrical performance, wherein the preparation method, each step and reagent and process parameter used in each step are the same as those of Example 1, except that the epoxy resin B is replaced by epoxy resin C, the curing agent B is replaced by curing agent C, and the curing process is (60℃, 2h) + (90℃, 3h) + (130℃, 5h) + (150℃, 2h).

[0039] Comparative Example 6

[0040] An epoxy resin composite material with superior electrical performance, wherein the preparation method, each step and reagent and process parameter used in each step are the same as those of Example 1, except that the epoxy resin B is replaced by epoxy resin C, and the curing agent B is replaced by curing agent C.

[0041] Comparative Example 7

[0042] An epoxy resin composite material with superior electrical performance, wherein the preparation method, each step and reagent and process parameter used in each step are the same as those of Example 1, except that the vacuumizing time before curing is 1h.

[0043] Comparative Example 8

[0044] An epoxy resin composite material with superior electrical performance, wherein the preparation method, each step and reagent and process parameter used in each step are the same as those of Example 1, except that the vacuumizing before curing is not performed.

[0045] Performance detection test

[0046] 1. Main test instruments: DWGH0600 program oven, Guangzhou Wanhe Test Instrument Co., Ltd.; JA5003 electronic balance, Shanghai Shangtian Precision Instrument Co., Ltd.; 6517B high resistance meter, USA KETHLEY; 2830 / 2831 high-precision liquid and solid insulating material analyzer, Switzerland TETTEX Company; NDHN-6 / 600V electric tracking resistance tester, Guilin Electrical Science Research Institute Co., Ltd.; HVM-3020F high-power measuring microscope, Guangdong Yuanxinghengzhun Precision Instrument Co., Ltd.

[0047] 2. Sample preparation: refer to GB / T 15022.2-2017 “Resin-based active composite for electrical insulation Part 2 Test methods” to prepare the sample.

[0048] 3. Porosity test: refer to GB / T 7019-2014 “Test methods for fiber cement products”, the measurement principle is: after the sample is treated in a 50℃±2℃ oven for 24h, immediately weigh it, which is m1; immerse the sample in deionized water at 23℃±2℃ to saturate, weigh the sample after wiping off the surface water, which is m3; immerse the sample in water and weigh it in water, which is m2; porosity K = V 孔 *100 / V 样 = (m3-m1)*100 / (m3-m2), the results are shown in Table 3.

[0049] 4. Thermal conductivity analysis: refer to GB / T 10295-2008 “Determination of thermal resistance and related properties of thermal insulations Steady-state heat flow meter method”, the temperature is selected as 50℃, the results are shown in Table 3.

[0050] 5. Surface resistivity: refer to GB / T 31838.3-2019 “Solid insulating materials-Dielectric and resistive properties-Part 3: Resistive properties (DC method)-Surface resistance and surface resistivity”, use a three-electrode system in 23℃±2℃ air, direct current voltage 500V and electrochemical 1min, the results are shown in Table 3.

[0051] 6. Relative permittivity and dielectric loss factor: refer to GB / T 1409-2006 “Recommended methods for measuring the permittivity and loss factor of electrical insulating materials at power frequencies, audio frequencies and radio frequencies (including wavelengths of 1 meter and longer)”, select frequency 50Hz, test in 23℃±2℃ air, the results are shown in Table 3.

[0052] 7. Electric-thermal combined aging test: refer to IEC 60343-1991 “Recommended test methods for determining the relative surface discharge breakdown resistance of solid insulating materials”, select 4#, 5# and 6# samples for electric-thermal combined aging performance test, including the following test contents:

[0053] ① Test sample and quantity: Φ100 mm x 0.5 mm x 2 mm x 0.2 mm, 10 pieces each (5 pieces for performance test before aging, 5 pieces for aging test);

[0054] ② Test conditions: temperature: 120 C ± 2 C, voltage: 10 kV, aging time: 1000 h, electrode selection: reference IEC60343 electrode, wherein the upper electrode (high electrode) is Φ6 mm x 0.2 mm, the edge is chamfered R1, the lower electrode (ground electrode) is a flat plate electrode, 5 independent electrode systems are required for each material;

[0055] ③ Aging procedure: install the test sample in the electrode holder, install the electrode holder in the electric heating aging oven, raise the temperature, when the temperature reaches 120 C ± 2 C and stabilizes for 1 h (the temperature inside and outside the test sample is balanced); when the temperature stabilizes for 1 h, apply voltage to the specified value (10 kV, ± 3%), during which the voltage and current changes at the interface of the voltage resistance instrument are closely observed and the timing is started; when the test sample breaks down or flashes, the time should be recorded in time, and whether the damaged test sample is breakdown or not should be checked, if it is breakdown, the high voltage of the test sample should be removed and the test should be continued until 5 test samples are damaged, if it is flash, the surface of the test sample should be cleaned;

[0056] ④ When the specified aging time 1000 h is reached without breakdown, the following performances of the aged test sample should be tested: appearance inspection, volume resistivity, surface resistivity, power frequency dielectric loss and dielectric constant, the results are shown in Tables 4-5.

[0057] Table 3-Performance test results of epoxy resin composite materials in the examples and comparative examples of the present application

[0058]

[0059]

[0060] According to the performance test results of Examples 1-3 and Comparative Examples 1-2 in Table 3, the increase of the content of silicon powder helps to improve the relative permittivity and thermal conductivity of the epoxy resin composite material, the thermal conductivity increases with the increase of the content of silicon powder in the epoxy resin system, and also changes with the change of the curing system, at the same time, the increase of the content of silicon powder can effectively reduce the dielectric loss factor, but the surface resistivity slightly decreases, the present application ensures that the surface resistivity is above 3 x 10 15 Ω, at the same time, the dielectric loss factor of the epoxy resin composite material is improved to 1.45 x 10 -2 Below, the thermal conductivity is above 0.5, and the porosity is below 0.3, the overall performance of the epoxy resin composite material is improved.

[0061] Based on the performance results of Examples 1-5 and Comparative Examples 3-6 in Table 3, it can be seen that the product obtained by epoxy resin A has an excessively high dielectric loss factor, while the product obtained by epoxy resin C does not meet the requirements for dielectric loss factor and thermal conductivity. By adding epoxy resins B, D or E, this application can obtain epoxy resin composite materials with lower dielectric loss factor and superior thermal conductivity.

[0062] Based on the performance test results of Example 1 and Comparative Examples 7-8 in Table 3, it can be seen that the porosity decreases with the increase of vacuum time during epoxy resin curing. Resins cured without vacuum generally have higher porosity, which leads to a decrease in the thermal conductivity of the product. Among them, the resins of Example 2 and Comparative Example 5 have lower porosity because their initial curing temperature during sample preparation is lower, which can eliminate some air bubbles. The surface resistivity decreases with increasing porosity, while the dielectric loss factor increases with increasing porosity because the air in the air bubbles affects the overall relative dielectric constant of the resin.

[0063] Table 4 - Aging failure time of epoxy resin composite materials in Examples 1 and 6 and Comparative Examples 1-2 of this application

[0064] Test item 1000h failure sample ratio Failure time Example 1 60％ 366h-790h Comparative Example 1 80％ 220h-834h Comparative Example 2 100％ 211h-854h

[0065] Table 5 - Performance test results before and after electrothermal aging of Example 1 and Comparative Examples 1-2 of this application

[0066]

[0067] As shown in Tables 4-5, under the same combined electrothermal aging conditions, the higher the silica powder content, the stronger the composite material's resistance to electrical stress. Under 1000h of treatment, the epoxy resin in Comparative Example 2, with the lowest silica powder content, destroyed 5 pieces, while in Example 1, with the highest content, only 3 pieces were destroyed. Furthermore, compared to Comparative Example 1, Example 1 maintained a high level of electrical performance after 1000h of electrothermal aging. Simultaneously, combined with... Figure 1 It can be seen that there is obvious white precipitate around the electrode of the Comparative Example 2 sample under electrical stress, and there is a ring of obvious black material. The Comparative Example 1 sample has less white precipitate and less black material than the 4# sample. The sample of Example 1 has even less white precipitate and black material. The more silica powder, the more effective it is to increase the epoxy resin system's resistance to electrothermal combined aging, and the better its resistance to electrothermal aging.

[0068] The above-described specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above-described specific embodiments are merely examples of the present application and are not intended to limit the protection scope of the present application. It is particularly pointed out that any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An epoxy resin composite material with superior electrical properties, characterized in that, It includes epoxy resin, curing agent and silica powder in a mass ratio of 1:1:3, wherein the silica powder has a mesh size of 300-400 mesh; The epoxy resin is the epoxy resin of grade HE-8329, the curing agent is the curing agent of grade HH-8329, and the curing process is: vacuuming for 2-5 hours and then curing at 135℃-145℃ for 11-13 hours. Alternatively, the epoxy resin is epoxy resin of grade EP-1511A, the curing agent is curing agent of grade EP-1511B, and the curing process is as follows: after vacuuming for 2 hours, cure at 80°C for 6 hours, cure at 100°C for 2 hours, cure at 130°C for 2 hours, and cure at 150°C for 2 hours.

2. A method for preparing an epoxy resin composite material with superior electrical properties as described in claim 1, characterized in that, The process includes the following steps: mixing epoxy resin and curing agent in a certain proportion, adding silica powder, stirring evenly, vacuuming, and then curing to obtain epoxy resin composite material.

3. The application of an epoxy resin composite material with superior electrical properties as described in claim 1 in the fields of power, energy, high-speed rail, and manufacturing.

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