A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet irradiation

Abstract

The present invention discloses a method for improving the surface flashover performance of epoxy resin in vacuum using ultraviolet radiation. A solid epoxy resin material is placed in an ultraviolet-irradiated vacuum chamber and surface-treated using deuterium lamp irradiation to improve the surface flashover performance of the solid epoxy resin material in vacuum. This method does not generate harmful gases and only alters the surface properties of the solid epoxy resin material, without significantly affecting the bulk properties of the material. Therefore, it has significant application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of high voltage and insulation, and particularly relates to a method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation. Background Art

[0002] Solid insulating media play an insulating and supporting role in modern power equipment and need to have sufficient dielectric strength and mechanical strength. Epoxy resin has been widely used in power equipment due to its good electrical properties and excellent mechanical properties. In addition, with the development of power equipment, vacuum environments have been widely used in power equipment due to their high insulation strength, light weight, and low cost. However, the surface flashover phenomenon occurring at the interface between vacuum and solid insulating materials seriously affects the reliability and stability of power equipment. The current status of surface flashover of epoxy resin in vacuum threatens the safe operation of power equipment and seriously restricts the development of high performance, miniaturization, and lightweight modern power equipment. Therefore, there is an urgent need to propose a method to increase the surface flashover voltage of epoxy resin in vacuum, improve the performance of various vacuum devices, and ensure the stable operation of key power equipment.

[0003] The generally accepted process of surface flashover development in academia consists of three main stages: ① the initial stage—the generation of initial electrons; ② the development stage—the formation of electron multiplication; and ③ the flashover stage—the formation of a through-gas discharge channel. Numerous methods have been proposed to improve the surface flashover voltage of insulating materials. These include improving the surface flashover performance of samples by modifying surface roughness, such as through coating and polishing; chemical surface treatments, such as surface fluorination, oxyfluorination, and ozone oxidation, to increase surface conductivity and shallow trap density, accelerate charge dissipation, suppress electron multiplication, and thus enhance surface flashover performance; and modifications to bulk material properties, such as micro- and nanoparticle doping. However, all of these treatment methods have limitations. For example, surface treatments using ozone oxidation, fluorination, and oxyfluorination can endanger the health of operators and use gases that are harmful to the environment. Bulk modification by doping with micro- and nanoparticles can improve the flashover performance of materials to a certain extent, but it also alters bulk properties, such as dielectric strength. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation to overcome the defects of the above-mentioned prior art. The method of the present invention does not produce harmful gases, and only changes the surface properties of the solid epoxy resin material, and does not have a significant impact on the bulk properties of the material. Therefore, it has important application value.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for improving the surface flashover performance of epoxy resin in vacuum based on ultraviolet irradiation, wherein a solid epoxy resin material is placed in an ultraviolet irradiation vacuum chamber and the surface of the solid epoxy resin material is treated by deuterium lamp irradiation to improve the surface flashover performance of the solid epoxy resin material in vacuum.

[0007] Furthermore, the method specifically includes the following steps:

[0008] S1: Preparation of solid epoxy resin material;

[0009] S2: The solid epoxy resin material prepared in S1 is ultrasonically cleaned with anhydrous ethanol and then dried at a constant temperature;

[0010] S3: placing the solid epoxy resin material obtained in S2 in a vacuum chamber of an ultraviolet irradiation system, and performing surface treatment on the solid epoxy resin material by irradiating with a deuterium lamp.

[0011] Furthermore, the S1 specifically includes:

[0012] 1) Clean the mold, spray the release agent and preheat it;

[0013] 2) stirring the liquid epoxy resin at a constant speed for 60 to 70 minutes at a temperature of 110 to 120° C., a rotation speed of 150 rad / min, and an air pressure of less than 100 Pa;

[0014] 3) adding the accelerator to the curing agent, followed by preheating and degassing to obtain a mixture A;

[0015] 3) lowering the temperature of the liquid epoxy resin obtained in step 2) to 100° C., adding mixture A, maintaining the temperature at 80-100° C., the air pressure at less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10-15 minutes to obtain mixture B;

[0016] 4) The mixture B obtained in step 3) is poured into the mold preheated in step 1) for curing, and then naturally cooled to room temperature to obtain a sample of a solid epoxy resin material.

[0017] Furthermore, in step 1), the preheating temperature is 100-120° C., and the preheating time is 2 hours.

[0018] Furthermore, in step 3), the preheating temperature is 60° C. and the degassing time is 15 min;

[0019] In step 3), the curing agent is methyltetrahydrophthalic anhydride, the accelerator is BDMA, and the mass ratio of the liquid epoxy resin, the curing agent and the accelerator is 100:80:0.6.

[0020] Furthermore, the curing procedure in step 4) is specifically as follows: treating at 80° C. for 2 h, and then treating at 140° C. for 14 h.

[0021] Furthermore, the ultrasonic cleaning time of anhydrous ethanol in S2 is 20 minutes, and the constant temperature drying temperature is 40-70° C. and the time is 6-14 hours.

[0022] Furthermore, the pressure in the vacuum chamber of S3 is 1×10 -3 Pa, temperature 20℃.

[0023] Furthermore, the wavelength of the deuterium lamp in S3 is 254 nm.

[0024] Furthermore, the irradiation time in S3 is 2-24 hours.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The present invention uses ultraviolet radiation to modify the surface of a solid epoxy resin material. Through ultraviolet radiation treatment, the surface chemical structure of the solid epoxy resin material is changed, the surface polar oxygen-containing groups are increased and their electron binding effect is enhanced, and electron emission is suppressed, thereby improving the vacuum surface flashover characteristics of the solid epoxy resin material.

[0027] Specifically, the surface of the solid epoxy resin material is treated by a high-intensity deuterium lamp. Since the deuterium lamp with a wavelength of 254nm emits high-energy ultraviolet light, it will destroy the chemical bonds with low bond energy on the surface of the solid epoxy resin material, forming broken bonds. The broken bonds on the surface of the sample react with the oxygen and water vapor in the cavity to generate new chemical bonds. Therefore, the surface chemical structure and water contact angle of the treated solid epoxy resin material change, specifically, the surface C=O content increases and the surface water contact angle increases. This change leads to the improvement of the surface flashover performance of the solid epoxy resin material under vacuum.

[0028] Furthermore, when the UV irradiation wavelength is 254 nm and the treatment time is 12 h, 1×10 -5 Pa, the AC surface flashover voltage of the epoxy resin sample before and after treatment was compared, and its flashover voltage increased by 21.83%.

[0029] In summary, the present invention can significantly improve the AC surface flashover voltage of epoxy resin insulation materials under vacuum, with a short processing time and obvious improvement effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1Schematic diagram of finger-type electrodes, where (a) is a top view and (b) is a front view;

[0032] Figure 2 The relationship between the flashover voltage and irradiation time is shown in the figure with the irradiation wavelength of 254, the sample diameter of 50mm, and the thickness of 1-2mm;

[0033] Figure 3 These are the infrared spectrum test graphs of epoxy resin samples after ultraviolet irradiation treatment for different lengths of time, where (a) is the infrared spectrum graph of each sample with an irradiation time of 0-12h, and (b) is the infrared spectrum graph of each sample with an irradiation time of 14-24h. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0037] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0038] 1) Clean the mold, spray the mold release agent, and preheat it in a 100-120℃ oven for 2 hours.

[0039] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 110-120°C, the rotation speed at 150 rad / min, the air pressure at less than 100 Pa, and stir at a constant speed for 60-70 minutes;

[0040] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0041] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 80-100° C., the air pressure at less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10-15 minutes to obtain mixture B;

[0042] 4) The obtained mixture B was poured into a mold preheated at 100-120°C for curing. The curing procedure was 80°C / 2h, 140°C / 14h, and then naturally cooled to room temperature to obtain specimens with a thickness of 1-2 mm and a diameter of 50 mm and 100 mm, respectively.

[0043] S2. The solid epoxy resin material prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 40 to 70 ° C for 6 to 14 h;

[0044] S3. Place the solid epoxy resin material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 - 3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0045] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform surface ultraviolet irradiation treatment on the solid epoxy resin material sample for 2-24h;

[0046] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0047] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1, three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0048] The present invention is further described in detail below with reference to specific embodiments:

[0049] Comparative Example

[0050] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0051] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0052] 1) Clean the mold, spray the mold release agent, and preheat it in a 100℃ oven for 2 hours.

[0053] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 110°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0054] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0055] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 80° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0056] 4) The obtained mixture B was poured into a mold preheated at 100°C for curing at a curing temperature of 80°C for 2 h and 140°C for 14 h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0057] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 40 ° C for 14 h;

[0058] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0059] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform UV irradiation on the surface of the sample, the irradiation time is 0h;

[0060] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0061] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0062] Example 1

[0063] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0064] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0065] 1) Clean the mold, spray the mold release agent, and preheat it in a 120℃ oven for 2 hours.

[0066] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0067] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0068] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 100° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0069] 4) The obtained mixture B was poured into a mold preheated at 120°C for curing at a curing schedule of 80°C / 2h and 140°C / 14h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0070] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 70 ° C for 6 h;

[0071] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0072] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform UV irradiation on the surface of the sample for 2 h;

[0073] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0074] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0075] Example 2

[0076] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0077] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0078] 1) Clean the mold, spray the mold release agent, and preheat it in a 105℃ oven for 2 hours.

[0079] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 115°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0080] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0081] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 82° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0082] 4) The obtained mixture B was poured into a mold preheated at 105°C for curing at a curing schedule of 80°C / 2h and 140°C / 14h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0083] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 50 ℃ for 12 h;

[0084] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0085] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform UV irradiation treatment on the surface of the sample for 4 h;

[0086] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0087] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0088] Example 3

[0089] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0090] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0091] 1) Clean the mold, spray the mold release agent, and preheat it in a 110℃ oven for 2 hours.

[0092] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 118°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0093] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0094] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 85° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0095] 4) The obtained mixture B was poured into a mold preheated at 110°C for curing at 80°C for 2 h and 140°C for 14 h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0096] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 60 ° C for 10 h;

[0097] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0098] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3Pa, turn on the high-energy deuterium lamp and perform ultraviolet irradiation treatment on the surface of the sample for 6 hours;

[0099] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0100] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0101] Example 4

[0102] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0103] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0104] 1) Clean the mold, spray the mold release agent, and preheat it in a 115℃ oven for 2 hours.

[0105] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 115°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0106] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0107] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 90° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0108] 4) The obtained mixture B was poured into a mold preheated at 115°C for curing at 80°C for 2 h and 140°C for 14 h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0109] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 55 ° C for 8 h;

[0110] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0111] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform UV irradiation treatment on the surface of the sample for 8 h;

[0112] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0113] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0114] Example 5

[0115] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0116] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0117] 1) Clean the mold, spray the mold release agent, and preheat it in a 100℃ oven for 2 hours.

[0118] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0119] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0120] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 95° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0121] 4) The obtained mixture B was poured into a mold preheated at 100°C for curing at a curing temperature of 80°C for 2 h and 140°C for 14 h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0122] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 65 ° C for 10 h;

[0123] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0124] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform ultraviolet irradiation treatment on the surface of the sample for 10 h;

[0125] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0126] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0127] Example 6

[0128] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0129] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0130] 1) Clean the mold, spray the mold release agent, and preheat it in a 120℃ oven for 2 hours.

[0131] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0132] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0133] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 95° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0134] 4) The obtained mixture B was poured into a mold preheated at 120°C for curing at a curing schedule of 80°C / 2h and 140°C / 14h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0135] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 40 ° C for 14 h;

[0136] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0137] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3Pa, turn on the high-energy deuterium lamp and perform UV irradiation treatment on the surface of the sample for 12 h;

[0138] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0139] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0140] Example 7

[0141] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0142] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0143] 1) Clean the mold, spray the mold release agent, and preheat it in a 115℃ oven for 2 hours.

[0144] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0145] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0146] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 100° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0147] 4) The obtained mixture B was poured into a mold preheated at 100-120°C for curing. The curing procedure was 80°C / 2h, 140°C / 14h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2mm and a diameter of 50mm.

[0148] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 70 ° C for 14 h;

[0149] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0150] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform surface ultraviolet irradiation treatment on the sample for 14 h;

[0151] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0152] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0153] Example 8

[0154] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0155] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0156] 1) Clean the mold, spray the mold release agent, and preheat it in a 120℃ oven for 2 hours.

[0157] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0158] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0159] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 80° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0160] 4) The obtained mixture B was poured into a mold preheated at 120°C for curing at a curing schedule of 80°C / 2h and 140°C / 14h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0161] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 40 ° C for 6 h;

[0162] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0163] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform surface ultraviolet irradiation treatment on the sample for 16 h;

[0164] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0165] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm.-1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0166] Example 9

[0167] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0168] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0169] 1) Clean the mold, spray the mold release agent, and preheat it in a 120℃ oven for 2 hours.

[0170] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0171] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0172] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 80° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0173] 4) The obtained mixture B was poured into a mold preheated at 100-120°C for curing. The curing procedure was 80°C / 2h, 140°C / 14h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2mm and a diameter of 50mm.

[0174] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 70 ° C for 6 h;

[0175] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0176] S4. Wait until the vacuum chamber pressure stabilizes to 1×10-3 Pa, turn on the high-energy deuterium lamp and perform ultraviolet irradiation treatment on the surface of the sample for 18 h;

[0177] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0178] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0179] Example 10

[0180] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0181] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0182] 1) Clean the mold, spray the mold release agent, and preheat it in a 110℃ oven for 2 hours.

[0183] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 110°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0184] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0185] 3) Lowering the temperature of the epoxy resin to 100°C, adding mixture A, maintaining the temperature at 100°C, the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0186] 4) The obtained mixture B was poured into a mold preheated at 110°C for curing at 80°C for 2 h and 140°C for 14 h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0187] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 70 ° C for 14 h;

[0188] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0189] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform ultraviolet irradiation treatment on the surface of the sample for 20 h;

[0190] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0191] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0192] Example 11

[0193] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0194] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0195] 1) Clean the mold, spray the mold release agent, and preheat it in a 105℃ oven for 2 hours.

[0196] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0197] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0198] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 100° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0199] 4) The obtained mixture B was poured into a mold preheated at 105°C for curing at a curing schedule of 80°C / 2h and 140°C / 14h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0200] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 50 ° C for 10 h;

[0201] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0202] S4. Wait until the vacuum chamber pressure stabilizes to 1×10 -3 Pa, turn on the high-energy deuterium lamp and perform surface ultraviolet irradiation treatment on the sample for 22 h;

[0203] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0204] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm.-1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0205] Example 12

[0206] A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, comprising the following steps:

[0207] S1. Prepare solid epoxy resin material, the specific steps are as follows:

[0208] 1) Clean the mold, spray the mold release agent, and preheat it in a 115℃ oven for 2 hours.

[0209] 2) Add liquid epoxy resin into a three-necked flask, maintain the temperature at 120°C, the rotation speed at 150 rad / min, the air pressure less than 100 Pa, and stir at a constant speed for 60 minutes;

[0210] 3) The accelerator was added to the curing agent in proportion, and the mixture was placed in a beaker, preheated in a 60°C oven, and degassed for 15 minutes to obtain a mixture A; wherein the curing agent was methyltetrahydrophthalic anhydride, the accelerator was BDMA, and the mass ratio of the liquid epoxy resin, the curing agent, and the accelerator was 100:80:0.6.

[0211] 3) Lowering the temperature of the liquid epoxy resin to 100° C., adding mixture A, maintaining the temperature at 100° C., the air pressure less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10 minutes to obtain mixture B;

[0212] 4) The obtained mixture B was poured into a mold preheated at 115°C for curing at 80°C for 2 h and 140°C for 14 h, and then naturally cooled to room temperature to obtain a sample with a thickness of 1-2 mm and a diameter of 50 mm.

[0213] S2. The solid epoxy resin prepared in S1 was ultrasonically cleaned with anhydrous ethanol and then dried in a constant temperature blast drying oven; wherein the ultrasonic cleaning time of anhydrous ethanol was 20 min, and the constant temperature drying temperature was 70 ° C for 14 h;

[0214] S3. Place the material obtained in S2 in the vacuum chamber of the UV irradiation system (pressure is 1×10 -3 Pa, temperature 20 ° C), using a D2Plus high-intensity deuterium lamp produced by Heraus. This deuterium lamp can stably output a wavelength of 254 nm.

[0215] S4. Wait until the vacuum chamber pressure stabilizes to 1×10-3 Pa, turn on the high-energy deuterium lamp and perform UV irradiation on the surface of the sample for 24 h;

[0216] S5. After irradiation, turn off the deuterium lamp, open the vacuum chamber, and remove the sample whose surface has been irradiated with the UV beam;

[0217] S6. Place the sample in S5 into the flashover test chamber with an air pressure of 1×10 -5 Pa, temperature is 20℃; select Figure 1 The finger electrodes shown were made of stainless steel, with a 10mm radius and a 6±0.05mm inter-electrode spacing. The power supply was AC, with a step-by-step voltage increase at a rate of 1kV / s. The interval between flashovers was 2 minutes, and the test was repeated eight times for each sample. Infrared spectroscopy was also performed on the samples, with a wavenumber of 3500cm. -1 ~500cm -1 , three points of each sample were tested and the average value was taken; then the water contact angle test was performed on the sample, deionized water was selected as the test liquid, five different positions of each sample surface were selected for testing, and the average value was taken as the water contact angle of the sample.

[0218] By using the method of the present invention, the AC surface flashover performance of the epoxy sample after 254nm ultraviolet irradiation in a vacuum environment shows that the flashover voltage first increases and then decreases with the increase of treatment time, and the optimal treatment time is 12h.

[0219] Attachment Figure 2 The AC surface flashover voltage of epoxy samples increased first and then decreased with increasing irradiation time. When the irradiation time was 12 h, the AC flashover voltage increased by 21.83% compared with the unirradiated samples.

[0220] Attachment Figure 3 As shown in the figure, the infrared spectrum test results show that when the irradiation time is 0-12h, the C=O and CO contents on the sample surface increase, and the CC and CH contents decrease. When the irradiation time exceeds 12h, the C=O, CO, CC, and CH contents on the sample surface decrease.

[0221] Table 1 shows the changes in water contact angle on the sample surface during irradiation time 0-24h.

[0222] Irradiation time (h) Water contact angle (°) 0 100.55 2 94.28 4 87.88 6 85.53 8 80 10 75.45 12 69.1 14 78.90 16 82.03 18 89.82 20 93.58 22 97.42 24 97.57

[0223] As shown in Table 1, as the irradiation time increases, the water contact angle on the epoxy sample surface first decreases and then increases. When the irradiation time is 12 h, the water contact angle is the smallest.

[0224] Experimental results show that the number of surface oxygen-containing functional groups on samples treated with UV irradiation initially increases and then decreases, while the surface water contact angle initially decreases and then increases. The modification effect is most pronounced at 12 hours of irradiation. At this time, the sample has the highest number of surface oxygen-containing functional groups and the lowest water contact angle. A smaller water contact angle indicates a higher content of C=O and CO introduced by irradiation, indicating a higher number of oxygen-containing polar groups on the sample surface. The introduction of oxygen-containing polar groups can enhance electron binding and suppress electron emission, significantly increasing the AC surface flashover voltage of epoxy resin materials under vacuum.

[0225] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art may still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation, characterized in that: The solid epoxy resin material is placed in an ultraviolet irradiation vacuum chamber, and the surface of the solid epoxy resin material is treated by deuterium lamp irradiation to improve the surface flashover performance of the solid epoxy resin material in vacuum. The method specifically includes the following steps: S1: Preparation of solid epoxy resin material; specifically including: 1) Clean the mold, spray the release agent and preheat it; 2) stirring the liquid epoxy resin at a constant speed for 60 to 70 minutes at a temperature of 110 to 120° C., a rotation speed of 150 rad / min, and an air pressure of less than 100 Pa; 3) adding the accelerator to the curing agent, followed by preheating and degassing to obtain a mixture A; 4) lowering the temperature of the liquid epoxy resin obtained in step 2) to 100° C., adding mixture A, maintaining the temperature at 80-100° C., the air pressure at less than 100 Pa, the rotation speed at 150 rad / min, and stirring uniformly for 10-15 minutes to obtain mixture B; 5) pouring the mixture B obtained in step 4) into the mold preheated in step 1) for curing, and then naturally cooling to room temperature to obtain a sample of a solid epoxy resin material; S2: The solid epoxy resin material prepared in S1 is ultrasonically cleaned with anhydrous ethanol and then dried at a constant temperature; S3: The solid epoxy resin material obtained in S2 is placed in a vacuum chamber of an ultraviolet irradiation system, and the surface of the solid epoxy resin material is treated by irradiation with a deuterium lamp. The pressure in the vacuum chamber is 1×10 -3 Pa, temperature 20℃, irradiation time 2-24h.

2. The method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation according to claim 1, characterized in that: In step 1), the preheating temperature is 100-120° C. and the preheating time is 2 h.

3. The method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation according to claim 1, characterized in that: In step 3), the preheating temperature is 60° C. and the degassing time is 15 min; In step 3), the curing agent is methyltetrahydrophthalic anhydride, the accelerator is BDMA, and the mass ratio of the liquid epoxy resin, the curing agent and the accelerator is 100:80:0.

6.

4. The method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation according to claim 1, characterized in that: The curing procedure in step 4) is specifically as follows: treating at 80° C. for 2 h, and then treating at 140° C. for 14 h.

5. The method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation according to claim 1, characterized in that: The ultrasonic cleaning time of anhydrous ethanol in S2 is 20 minutes, and the constant temperature drying temperature is 40-70° C. and the time is 6-14 hours.

6. The method for improving the vacuum surface flashover performance of epoxy resin based on ultraviolet radiation according to claim 1, characterized in that: The wavelength of the deuterium lamp in S3 is 254 nm.

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