Extra-high-voltage direct-current epoxy insulating material and preparation method thereof

Abstract

The invention belongs to the technical field of polymer insulating materials, and particularly discloses an extra-high-voltage direct-current epoxy insulating material and a preparation method thereof. The core of the method is that fluorine-containing polyrotaxane is introduced into an epoxy crosslinking system as a modifier: (1) hydroxyl on the surface of a cyclic host molecule of the fluorine-containing polyrotaxane participates in crosslinking, so that the structural strength of the material is maintained, and the cracking resistance is remarkably improved; and (2) in the curing process, the fluorine element contained in the polyrotaxane is spontaneously enriched towards the surface layer of the material to form a superficial fluorine layer. Carriers in a fluorine layer barrier material body migrate to the surface under a direct-current normal electric field, the surface energy of the material is effectively reduced, adsorption and deposition of environmental impurity particles are inhibited, abnormal accumulation of surface charges is jointly prevented through dual mechanisms, the flashover risk caused by electric field distortion is avoided, and the service life of the material is prolonged. And the long-term insulation reliability in an extra-high voltage direct current operation environment is greatly improved. The problem of insulation failure caused by easy cracking of a basin-type insulator epoxy material and surface charge accumulation in a high-voltage direct-current GIS is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer insulation materials, and specifically discloses an ultra-high voltage direct current epoxy insulation material and a preparation method thereof. Background Art

[0002] In UHVDC gas-insulated switchgear (GIS), the pot insulator is a key component providing mechanical support and electrical isolation, making the long-term reliability of its epoxy material crucial. The harsh operating environment of UHVDC places dual core demands on epoxy materials: excellent crack resistance and superior surface withstand voltage. The former stems from the complex thermal-mechanical-electrical coupling fields experienced by insulators during long-term service, where the initiation and propagation of microcracks can easily lead to structural failure. The latter stems from the continuous accumulation of carriers (ions and space charge) within the material, driven by the normal electric field component, on the insulator surface under the action of a unipolar HVDC electric field. This, coupled with the adsorption of surface impurities, causes severe surface electric field distortion, significantly reducing the flashover voltage and becoming the primary cause of DC insulation failure. These two performance characteristics directly determine the mechanical integrity and electrical safety of the pot insulator and are the cornerstone of stable UHVDC system operation.

[0003] Currently, the mainstream approach to improving the surface withstand voltage performance of epoxy insulators focuses on surface modification techniques, such as surface fluorination, plasma modification, or spraying fluorine-containing coatings, aimed at reducing surface energy and inhibiting charge accumulation. However, these methods have significant limitations: drastic intervention in the modification process (especially fluorination or plasma treatment) can damage or even destroy the cross-linked network structure on the epoxy matrix surface, impairing insulator performance. More importantly, the resulting surface functional layer is primarily based on physical attachment or superficial reactions, lacking a strong chemical bond with the epoxy matrix. It is highly susceptible to degradation and flaking under long-term electro-thermal-mechanical stress and environmental aging, resulting in a short-lived and unreliable effect on suppressing charge accumulation, poor timeliness, and difficulty meeting the lifespan requirements of UHVDC equipment. Therefore, these surface modifications contribute insufficiently to improving the material's inherent crack resistance and are unable to synergistically address the dual mechanical and electrical challenges facing pot-type insulators. Summary of the Invention

[0004] One of the objectives of the present invention is to provide an ultra-high voltage direct current epoxy insulation material and a preparation method thereof. The active hydroxyl groups on the surface of the polyrotaxane are utilized to participate in cross-linking, becoming embedded components of the epoxy network. The unique mechanical interlocking structure can effectively dissipate stress by slip, significantly enhancing the material's crack resistance. At the same time, during the curing process, the fluorine elements on the polyrotaxane spontaneously migrate to the surface and enrich to form a shallow fluorine layer chemically bonded to the matrix, inhibiting the migration of carriers to the surface, reducing the surface energy of the insulator, and reducing the adsorption of impurity particles, thereby long-term and stably inhibiting surface charge accumulation and simultaneously improving the surface withstand voltage performance.

[0005] To achieve the above object, the present invention adopts the following technical solution: a method for preparing an ultra-high voltage direct current epoxy insulation material, comprising the following steps: S1. Dissolve fluorinated cyclodextrin and polyethylene glycol diamine with a molecular weight of 3000-10000 g / mol in deionized water, respectively. Then slowly add the fluorinated cyclodextrin aqueous solution dropwise to the polyethylene glycol diamine aqueous solution. After vigorous stirring at 80-100° C., cool naturally to room temperature. The product is freeze-dried to obtain a fluorinated pseudopolyrotaxane. S2. Dissolve the fluorinated pseudopolyrotaxane in anhydrous N,N-dimethylamide, slowly dropwise add the end-capping agent 2,4-dinitrofluorobenzene, and fully stir the reaction at room temperature. After the reaction is completed, add excess acetone to precipitate the product, wash and dry to obtain the fluorinated polyrotaxane; S3. The fluorinated polyrotaxane is fully mixed with bisphenol A epoxy resin, curing agent and accelerator at 70-90°C and then degassed under vacuum. The mixture is then poured into a mold, and low-temperature pre-curing and high-temperature curing are performed in sequence. After cooling to room temperature, the mixture is demoulded to obtain a UHVDC epoxy insulation material.

[0006] As a further improvement of the preparation method of UHVDC epoxy insulation material: Preferably, in step S1, the mass ratio of fluorinated cyclodextrin to polyethylene glycol diamine is (2-5):1.

[0007] Preferably, in step S1, the concentration of fluorinated cyclodextrin in the fluorinated cyclodextrin aqueous solution is 0.06-0.13 g / mL, and the concentration of polyethylene glycol diamine in the polyethylene glycol diamine aqueous solution is 0.02-0.032 g / mL.

[0008] Preferably, in step S2, the concentration of the fluorinated pseudopolyrotaxane dissolved in anhydrous N,N-dimethylamide is 0.025-0.05 g / mL, and the mass ratio of the fluorinated pseudopolyrotaxane to the end-capping agent 2,4-dinitrofluorobenzene is 1:(1-1.5).

[0009] Preferably, in step S3, the mass ratio of the fluorinated polyrotaxane to the bisphenol A epoxy resin, the curing agent, and the accelerator is (3-12):100:(70-100):(0.3-0.6).

[0010] Preferably, the curing agent in step S3 is an acid anhydride curing agent.

[0011] Preferably, the curing agent in step S3 is one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride.

[0012] Preferably, the accelerator in step S3 is one of N,N-dimethylbenzylamine and 2,4,6-tris(dimethylaminomethyl)phenol.

[0013] Preferably, in step S3, the temperature of the low-temperature pre-curing is controlled at 70-90° C., and the curing time is 4-9 hours; the temperature of the high-temperature curing is controlled at 100-130° C., and the curing time is 10-20 hours.

[0014] A second object of the present invention is to provide an ultra-high voltage direct current epoxy insulation material prepared by any one of the methods for preparing the ultra-high voltage direct current epoxy insulation material.

[0015] The beneficial effects of the present invention compared to the prior art are: (1) This invention addresses two key technical challenges of existing UHVDC epoxy insulation materials: insufficient bulk cracking resistance and poor long-term surface charge suppression capability. It provides a customized molecular network design method. This design is based on the following technical principles: Molecular slip dissipation mechanism: Fluorinated polyrotaxane modifiers, chemically bonded and embedded in the cross-linked network, have a unique structure in which the cyclic main molecule is encased in the polymer spool, forming a natural molecular-scale "slip ring" unit. When the material is subjected to external or internal stress (thermal stress, mechanical stress), these slip ring structures can undergo reversible relative slip motion, dissipating energy through intramolecular friction and highly efficient conformational changes. This nanoscale slip dissipation mechanism can blunt crack tips, effectively preventing the initiation and propagation of microcracks, and significantly improving the toughness and resistance to environmental stress cracking of epoxy materials. Unlike simple toughening agent filling, this mechanism relies on the topological structural properties of the modifier itself, allowing it to maintain a high cross-link density (the hydroxyl groups of the polyrotaxane participate in the cross-linking reaction) while still providing excellent stress relaxation.

[0016] Controllable directional surface enrichment: During the curing and crosslinking process of epoxy resin, the fluorine-containing groups carried by the polyrotaxane are driven by the interfacial energy gradient (low surface energy characteristics), spontaneously and directionally migrate and preferentially accumulate in the surface area of ​​the material. Crucially, this enrichment process occurs simultaneously with the participation of the polyrotaxane in the epoxy crosslinking reaction through the hydroxyl groups. This means that the resulting surface fluorine-rich layer is not a simple physical coating or adsorption layer, but is firmly bonded to the epoxy matrix crosslinking network through chemical bonds. This bonding method ensures excellent interfacial adhesion and long-term stability between the fluorine layer and the substrate.

[0017] Charge suppression mechanism: This fluorine-containing layer alters the superficial energy level structure of the material, significantly hindering the migration of charge carriers to the surface caused by the normal electric field. This is a key factor in improving the surface withstand voltage of the insulator. Furthermore, the superficial fluorine-containing layer imparts an extremely low critical surface tension to the material surface, significantly reducing the tendency of suspended impurity particles in the environment to adsorb on the insulator surface. This significantly inhibits surface carrier accumulation, thus avoiding the electric field distortion caused by the generation of additional field strength, which can lead to the premature occurrence of surface flashover.

[0018] (2) Traditional technologies rely on post-treatment modifications of the surface, such as surface fluorination, plasma treatment, or spraying of fluorine-containing coatings. Although these methods can improve surface properties (such as reducing surface energy) in the short term, they have fundamental flaws: on the one hand, their intense treatment processes (such as high-energy particle bombardment and strong chemical reactions) can damage or even destroy the cross-linked network structure of the epoxy matrix surface, potentially weakening the bulk insulation and mechanical properties of the material; on the other hand, more critically, the surface functional layer formed is mainly based on physical adsorption or superficial physical and chemical reactions, and lacks a strong chemical bond with the epoxy matrix. Under the effects of electrical, thermal, and mechanical stress cycles and environmental aging during long-term operation, it is very easy to degrade, peel off, or fail.

[0019] (3) The present invention provides a UHVDC epoxy insulating material and a preparation method thereof having the following advantages: a fluorinated polyrotaxane is introduced into the epoxy cross-linked network through chemical bonding, thereby achieving synergistic bulk modification. The modifier significantly enhances the material's crack resistance toughness through the mobility of its molecular slip ring structure; at the same time, a chemically bonded superficial fluorine layer is spontaneously formed during the curing process, which can effectively block bulk charge migration, reduce surface energy, inhibit dirt adsorption, and stably inhibit surface charge accumulation. The present invention overcomes the shortcomings of traditional surface treatments, such as high destructiveness, poor timeliness, and inability to achieve synergistic improvements, and enables the insulating material to have both excellent crack resistance and insulation strength in UHVDC environments. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] Example 1 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material, and the specific steps are as follows: S1. Dissolve 20 g of fluorinated cyclodextrin and 4 g of polyethylene glycol diamine (molecular weight, 6000 g / mol) in 200 mL of deionized water, then slowly add the fluorinated cyclodextrin aqueous solution dropwise to the polyethylene glycol diamine aqueous solution. Stir vigorously at 80°C for 2 h, then naturally cool to room temperature, and freeze-dry for 24 h to obtain a fluorinated pseudopolyrotaxane. Among them, the molecular structure of fluorinated cyclodextrin is as follows: ; S2. Dissolve 15 g of the fluorinated pseudopolyrotaxane in 300 mL of anhydrous N,N-dimethylformamide, slowly add dropwise 15 g of the end-capping agent 2,4-dinitrofluorobenzene, and stir the mixture at room temperature. After the reaction is complete, add excess acetone to precipitate the product, wash, and dry to obtain the fluorinated polyrotaxane. S3. The above-mentioned fluorinated polyrotaxane (5g) is fully mixed with bisphenol A epoxy resin (100g), methyltetrahydrophthalic anhydride curing agent (88.9g), and N,N-dimethylbenzylamine accelerator (0.5g) at 80°C and then degassed in vacuo. The mixture is then poured into a mold and subjected to low-temperature pre-curing and high-temperature curing in sequence. The low-temperature pre-curing temperature is 80°C and the time is 7h; the high-temperature curing temperature is 110°C and the time is 16h. After curing is completed, the mixture is naturally cooled to room temperature and demolded to obtain ultra-high voltage DC epoxy insulation material 1.

[0022] Example 2 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, except that: in step S1, 13 g of fluorinated cyclodextrin and 3.2 g of polyethylene glycol diamine (molecular weight 3000 g / mol) are separately dissolved in 100 mL of deionized water; in step S2, the fluorinated pseudopolyrotaxane (12 g) is dissolved in 300 mL of anhydrous N,N-dimethylformamide, and 18 g of a capping agent, 2,4-dinitrofluorobenzene, is slowly added dropwise.

[0023] Finally, the ultra-high voltage direct current epoxy insulation material 2 is obtained.

[0024] Example 3 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, except that: in step S1, 12 g of fluorinated cyclodextrin and 6 g of polyethylene glycol diamine (molecular weight 10,000 g / mol) are separately dissolved in 200 mL of deionized water; in step S2, 7.5 g of the fluorinated pseudopolyrotaxane is dissolved in 300 mL of anhydrous N,N-dimethylformamide, and 9 g of a capping agent, 2,4-dinitrofluorobenzene, is slowly added dropwise.

[0025] Finally, the ultra-high voltage direct current epoxy insulation material 3 is obtained.

[0026] Example 4 This embodiment provides a method for preparing an ultra-high voltage direct current (UHVDC) epoxy insulation material. The specific steps are similar to those of Example 1, except that: in step S3, the fluorinated polyrotaxane (3 g) is thoroughly mixed with a bisphenol A epoxy resin (100 g), a methyltetrahydrophthalic anhydride curing agent (70 g), and an N,N-dimethylbenzylamine accelerator (0.3 g) at 80°C and then degassed under vacuum; ultimately, ultra-high voltage direct current (UHVDC) epoxy insulation material 4 is obtained.

[0027] Example 5 This embodiment provides a method for preparing an ultra-high voltage direct current (UHVDC) epoxy insulation material. The specific steps are similar to those of Example 1, except that: in step S3, the fluorinated polyrotaxane (12 g) is thoroughly mixed with a bisphenol A epoxy resin (100 g), a methyltetrahydrophthalic anhydride curing agent (100 g), and an N,N-dimethylbenzylamine accelerator (0.6 g) at 80°C and then degassed under vacuum; ultimately, an ultra-high voltage direct current (UHVDC) epoxy insulation material 5 is prepared.

[0028] Example 6 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, with the only difference being that in step S3, the low-temperature pre-curing temperature is 90°C for 4 hours, and the high-temperature curing temperature is 130°C for 10 hours. Finally, ultra-high voltage direct current epoxy insulation material 6 is obtained.

[0029] Example 7 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, with the only difference being that in step S3, the low-temperature pre-curing temperature is 70°C for 9 hours, and the high-temperature curing temperature is 100°C for 20 hours. Finally, ultra-high voltage direct current epoxy insulation material 7 is obtained.

[0030] Comparative Example 1 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, except that: Steps S1 and S2 are not performed, and bisphenol A epoxy resin (100 g), a curing agent (methyltetrahydrophthalic anhydride, 88.9 g), and an accelerator (N,N-dimethylbenzylamine, 0.5 g) are directly mixed thoroughly at 60° C. and then vacuum degassed. The mixture is then poured into a mold and subjected to low-temperature pre-curing and high-temperature curing, respectively. The low-temperature pre-curing temperature is 80° C. for 7 hours, and the high-temperature curing temperature is 110° C. for 16 hours. After curing is completed, the mixture is naturally cooled to room temperature and demolded, thereby producing ordinary epoxy insulation material 1.

[0031] Comparative Example 2 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, with the only difference being that β-cyclodextrin is used instead of fluorinated cyclodextrin in step S1, and step S2 is performed to obtain a common polyrotaxane; and then step S3 is performed to obtain a common epoxy insulation material 2.

[0032] Comparative Example 3 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those in Example 1, except that: in step S1, the molecular weight of polyethylene glycol diamine is 20,000 g / mol; Finally, ordinary epoxy insulation material 3 is obtained.

[0033] Comparative Example 4 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, with the only difference being that the amount of fluorinated polyrotaxane added in step S3 is 20 g; and finally, ordinary epoxy insulation material 4 is obtained.

[0034] Comparative Example 5 This embodiment provides a method for preparing an ultra-high voltage direct current epoxy insulation material. The specific steps are similar to those of Example 1, with the only difference being that in step S3, the low-temperature pre-curing temperature is 100°C for 3 hours, and the high-temperature curing temperature is 150°C for 9 hours; and finally, ordinary epoxy insulation material 5 is obtained.

[0035] The epoxy insulation samples prepared in the above examples and comparative examples were subjected to impact strength testing, surface flashover testing, and withstand voltage testing. The impact strength test was conducted in accordance with the national standard GB / T 1043.1-2008. The surface flashover test was conducted in accordance with the national standard, using finger-type electrodes with a spacing of 20 mm and room temperature. The surface flashover voltage was increased at a constant rate of 1 kV / s until surface flashover occurred. The surface withstand voltage test was conducted for a long period of time at a voltage 0.9 times the surface flashover voltage until surface flashover occurred.

[0036] Table 1 Performance test of epoxy insulation samples prepared in Examples 1-7 and Comparative Examples 1-5 ; As can be seen from Examples 1-7 in Table 1, by changing the amount of fluorinated cyclodextrin, the molecular weight of polyethylene glycol diamine, the addition ratio of fluorinated polyrotaxane, the type of curing agent and accelerator, the curing temperature and time and other variables, the preparation methods provided in this application can effectively achieve a synergistic improvement in its crack resistance and surface withstand voltage performance to meet the requirements of ultra-high voltage direct current application scenarios. The mechanism for improving crack resistance is that the surface of the fluorinated polyrotaxane structure is rich in hydroxyl groups, which can participate in the curing process together with the resin and curing agent to form a cross-linked network, which is beneficial to increase the cross-linking density and maintain the overall rigidity of the network; on the basis of the high strength of the network, the special mechanical structure of the polyrotaxane is used to improve the material's crack resistance. When the insulator is subjected to stress shock during production, installation and operation, the stress is transferred to the polyrotaxane through the high-strength network. The polyrotaxane undergoes slip motion to relax the stress, hindering the development of cracks caused by chemical bond breakage, thereby achieving a significant improvement in crack resistance. The mechanism for improving the surface voltage resistance performance is that: during the curing process, due to the suitable temperature and duration, the fluorine-containing groups introduced on the surface of the polyrotaxane gradually migrate to the surface until the curing is completed, and a fluorine-containing layer is formed on the shallow surface of the material; on the one hand, this fluorine-containing layer changes the energy level structure of the shallow layer, hinders the electrons migrating from the body, and reduces the surface charge content; on the other hand, it increases the surface energy of the material, making it difficult for impurity particles to be adsorbed; under the synergistic effect, the accumulation of surface charge of the insulating material is improved, the degree of electric field distortion is suppressed, and the surface voltage resistance time is improved.

[0037] It can be seen from Example 1 and Comparative Example 1 that the impact strength and surface withstand voltage time of ordinary epoxy insulating materials that do not introduce a fluorinated polyrotaxane structure are difficult to meet the requirements of the UHVDC scenario. It can be seen from Example 1 and Comparative Example 2 that although the impact strength is improved by introducing non-fluorinated polyrotaxane, its insulation strength is still difficult to meet the requirements. It can be seen from Example 1 and Comparative Example 3 that the fluorinated polyrotaxane structure uses a chain polyethylene glycol diamine with a higher molecular weight, and its impact strength is not significantly improved, and the surface withstand voltage time is reduced. This may be because the overly long chain molecules produce too high a steric hindrance and provide too strong a network motion ability. It can be seen from Example 1 and Comparative Example 4 that an excessively high addition ratio of fluorinated polyrotaxane will cause the deterioration of impact strength and surface withstand voltage time. This may be because the excess fluorinated polyrotaxane structure destroys the epoxy cross-linked network structure. It can be seen from Example 1 and Comparative Example 5 that inappropriate curing temperature and time cannot effectively make the fluorinated structure aggregate to the shallow surface layer of the material during the curing process, so that its surface withstand voltage time is not significantly improved.

[0038] Those skilled in the art will appreciate that the foregoing descriptions are merely specific embodiments of the present invention, and not exhaustive. It should be noted that numerous variations and modifications are possible for those skilled in the art, and all such variations and modifications that do not exceed the scope of the claims should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an ultra-high voltage direct current epoxy insulation material, characterized in that: The following steps are involved: S1. Dissolve fluorinated cyclodextrin and polyethylene glycol diamine with a molecular weight of 3000-10000 g / mol in deionized water, respectively. Then slowly add the fluorinated cyclodextrin aqueous solution dropwise to the polyethylene glycol diamine aqueous solution. After vigorous stirring at 80-100° C., cool naturally to room temperature. The product is freeze-dried to obtain a fluorinated pseudopolyrotaxane. S2. Dissolve the fluorinated pseudopolyrotaxane in anhydrous N,N-dimethylamide, slowly dropwise add the end-capping agent 2,4-dinitrofluorobenzene, and fully stir the reaction at room temperature. After the reaction is completed, add excess acetone to precipitate the product, wash and dry to obtain the fluorinated polyrotaxane; S3. The fluorinated polyrotaxane is fully mixed with bisphenol A epoxy resin, curing agent and accelerator at 70-90°C and then degassed under vacuum. The mixture is then poured into a mold, and low-temperature pre-curing and high-temperature curing are performed in sequence. After cooling to room temperature, the mixture is demoulded to obtain a UHVDC epoxy insulation material.

2. The method for preparing a UHVDC epoxy insulation material according to claim 1, characterized in that: The mass ratio of fluorinated cyclodextrin to polyethylene glycol diamine in step S1 is (2-5):

1.

3. The method for preparing a UHVDC epoxy insulation material according to claim 1 or 2, characterized in that: In step S1, the concentration of fluorinated cyclodextrin in the fluorinated cyclodextrin aqueous solution is 0.06-0.13 g / mL, and the concentration of polyethylene glycol diamine in the polyethylene glycol diamine aqueous solution is 0.02-0.032 g / mL.

4. The method for preparing a UHVDC epoxy insulation material according to claim 1 or 2, characterized in that: In step S2, the concentration of the fluorinated pseudopolyrotaxane dissolved in anhydrous N,N-dimethylamide is 0.025-0.05 g / mL, and the mass ratio of the fluorinated pseudopolyrotaxane to the end-capping agent 2,4-dinitrofluorobenzene is 1:(1-1.5).

5. The method for preparing a UHVDC epoxy insulation material according to claim 1, characterized in that: In step S3, the mass ratio of the fluorinated polyrotaxane to the bisphenol A epoxy resin, the curing agent, and the accelerator is (3-12):100:(70-100):(0.3-0.6).

6. The method for preparing a UHVDC epoxy insulation material according to claim 1, characterized in that: The curing agent in step S3 is an acid anhydride curing agent.

7. The method for preparing a UHVDC epoxy insulation material according to claim 1, characterized in that: In step S3, the curing agent is one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride.

8. The method for preparing a UHVDC epoxy insulation material according to claim 1, characterized in that: In step S3, the accelerator is one of N,N-dimethylbenzylamine and 2,4,6-tris(dimethylaminomethyl)phenol.

9. The method for preparing a UHVDC epoxy insulation material according to claim 1, characterized in that: In step S3, the temperature of the low-temperature pre-curing is controlled at 70-90° C., and the curing time is 4-9 hours; the temperature of the high-temperature curing is controlled at 100-130° C., and the curing time is 10-20 hours.

10. An ultra-high voltage direct current epoxy insulation material produced by the method for producing an ultra-high voltage direct current epoxy insulation material according to any one of claims 1 to 9.