A compounded toughening aid, composition, composite, insulating member, and method

Abstract

The application discloses a compounded toughening aid, a composition, a composite material, an insulating component and a method. The compounded toughening aid is compounded by a reactive long-chain polyether toughening agent and a polydopamine liquid polysulfide rubber coating liquid; the toughening impact-resistant epoxy resin composition contains, by weight, 100 parts of epoxy resin, 70-100 parts of an acid anhydride curing agent, 1-15 parts of the compounded toughening aid and 0.125-1.25 parts of an accelerator; and the composite material is compounded by the resin and glass fibers. The polydopamine is used to coat the polysulfide rubber, the agglomeration tendency of the polysulfide rubber is reduced, the reaction rate in the processing window period is delayed, and the viscosity is prevented from sharply increasing; the polyether toughening agent reduces the initial viscosity of the system and synergistically toughens. The application greatly improves the elongation at break and impact resistance of the resin and the composite material under the premise of maintaining low viscosity, long processing window period and unchanged insulating heat resistance, and meets the pouring demand of insulating pull rods.

Description

Technical Field

[0001] This invention belongs to the field of electrical composite technology, specifically relating to a compound toughening agent, composition, composite material, insulating component and method. Background Technology

[0002] Epoxy resin, as a typical thermosetting polymer material, has long been widely used in the field of electrical equipment manufacturing due to its excellent electrical insulation properties, mechanical strength, and good dimensional stability. Especially in applications requiring integrated casting and defect-free internal insulation and support structures such as dry-type reactors, instrument transformers, bushings, and insulating tie rods, epoxy resin plays an irreplaceable role. Among these, the insulating tie rod is a key component in ultra-high voltage gas-insulated metal-enclosed switchgear (GIS) circuit breakers. Its main structure is made of glass fiber reinforced epoxy resin composite, and its primary function is to transmit the movement of the operating mechanism from the grounding side to the high-potential side to achieve electrical connection switching. In actual service, the insulating tie rod must withstand extremely high instantaneous tensile or compressive loads during breaking operations, and is repeatedly subjected to mechanical load impacts and inrush current disturbances during frequent closing operations. Therefore, the impact resistance and toughness of the insulating tie rod material are key indicators determining its operational stability. Operational experience and research indicate that insulating tie rods made of fiber-reinforced epoxy resin composites typically have a high margin in insulation performance. Their main failure mode stems from mechanical fatigue caused by frequent switching operations. Under frequent mechanical impacts and load shocks, the material is prone to cracking or producing localized debris, leading to damage to the integrity of the insulation structure and subsequently internal breakdown discharge. Alternatively, under the influence of a strong electric field, debris adheres to the tie rod surface, forming a conductive path and ultimately causing surface flashover failure. Therefore, improving the toughness and overall impact resistance of the epoxy resin matrix has become a core issue that urgently needs to be addressed to ensure the long-term reliable operation of circuit breakers.

[0003] However, the molding process of insulating tie rods places extremely stringent processing requirements on the epoxy resin formulation system. Unlike ordinary cast parts, insulating tie rods employ an integrated vacuum casting process, requiring the epoxy resin to be fully impregnated in a mold containing dense glass fibers, and ensuring that premature curing does not occur during the high-temperature impregnation process. Integrated vacuum casting requires continuous injection to thoroughly remove air bubbles from the resin and between the fibers, a process that typically takes 2-3 hours. This necessitates that the matching epoxy resin formulation system possess both extremely low initial viscosity and an extremely long processing window. In existing epoxy resin formulation designs, to meet the aforementioned requirements of low viscosity and a long processing window, it is often necessary to sacrifice the toughness parameters of the formulation system, resulting in higher brittleness in the cured product and composite material, objectively increasing the failure risk of the insulating tie rod under frequent impact conditions.

[0004] To improve the brittleness of epoxy resins, existing technologies often employ modification by adding rubber-based toughening agents or elastomer particles. Among these, flexible segmental polymers such as liquid polysulfide rubber exhibit excellent toughening potential among reactive toughening agents. However, directly introducing such liquid rubbers into epoxy resin casting systems can lead to serious process defects: Firstly, liquid polysulfide rubber itself has extremely high viscosity and limited compatibility with the epoxy resin matrix, making it prone to agglomeration after mixing, resulting in an uneven cross-linking network. Secondly, and more critically, the active groups (such as thiol groups) contained in this type of rubber readily react with epoxy groups under high-temperature casting conditions, resulting in partial cross-linking during the impregnation stage. This causes the system viscosity to rise sharply within the processing window, even leading to gelation. This dramatic increase in viscosity prevents the adhesive from further diffusing and impregnating within the glass fiber layer, ultimately resulting in insufficient adhesive, numerous internal pores, and defects in the cast product.

[0005] Therefore, traditional toughening methods cannot simultaneously achieve both toughening effect and system processing performance. How to effectively improve the toughness and impact resistance of epoxy resin formulations while maintaining their low viscosity, long processing window, and excellent insulation and heat resistance is a major technical bottleneck in this field. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of insufficient toughness and impact resistance of existing epoxy resin formulations, and the problems that the introduction of toughening materials will lead to increased system viscosity and shortened processing window.

[0007] The objective of this invention is achieved through the following technical solution: A compound toughening agent includes a polydopamine-encapsulated liquid polysulfide rubber and a reactive long-chain polyether toughening agent; the polydopamine-encapsulated liquid polysulfide rubber has a polydopamine coating structure.

[0008] Preferably, the mass ratio of the polydopamine-encapsulated liquid polysulfide rubber to the reactive long-chain polyether toughening agent is 1:1.5 to 1:3.

[0009] Preferably, the liquid polysulfide rubber is a low molecular weight liquid polysulfide rubber with a molecular weight of 1000 to 4000.

[0010] Preferably, the reactive long-chain polyether toughening agent is selected from at least one of polyether polyols, polyether amines, or long-chain polyethers containing terminal active groups. Among existing commercial toughening agents, at least one of QS-N, QS-210B, and QS-VA3 can be selected.

[0011] Based on the same inventive concept, the present invention also provides a toughened and impact-resistant epoxy resin composition, wherein the composition comprises, by weight, 100 parts epoxy resin, 70-100 parts acid anhydride curing agent, 1-15 parts of the compounded toughening additive, and 0.125-1.25 parts accelerator.

[0012] Preferably, the compound toughening agent is used in amounts of 2.5 to 12.5 parts.

[0013] Preferably, the anhydride curing agent is a reversible covalent anhydride system curing agent.

[0014] Preferably, the curing agent of the reversible covalent anhydride system is methyl nadic anhydride, and the addition amount is 80-90 parts by weight; the addition amount of the compound toughening agent is 5-10 parts by weight; and the addition amount of the accelerator is 0.25-0.75 parts by weight.

[0015] Preferably, the amount of methylnadic anhydride added is 85 parts by weight; the amount of the compound toughening agent added is 7.5 parts by weight; and the amount of the accelerator added is 0.25 parts by weight.

[0016] Preferably, the epoxy resin is bisphenol A type epoxy resin E-51 or CLP-128.

[0017] Preferably, the promoter is 1,2-dimethylimidazole or 2-propylimidazole.

[0018] Based on the same inventive concept, the present invention also provides a fiber-reinforced epoxy resin composite, comprising the toughened and impact-resistant epoxy resin composition and glass fiber.

[0019] Based on the same inventive concept, the present invention also provides a method for preparing a compound toughening agent, comprising the following steps: A rubber dispersion was prepared by dispersing liquid polysulfide rubber in an aqueous solution containing a weakly alkaline buffer solution. Dopamine or dopamine salt is added to the rubber dispersion and mixed to obtain a mixture; An alkaline regulator was added to the mixture to adjust the pH of the system to 8-9, and the reaction was stirred to obtain a reaction solution. The reaction solution is centrifuged and the lower precipitate is collected. Deionized water is added to the precipitate to redisperse it. The centrifugation-dispersion operation is repeated multiple times to obtain the separated precipitate. The separated precipitate was freeze-dried to prepare polydopamine-encapsulated liquid polysulfide rubber particles. The polydopamine-encapsulated liquid polysulfide rubber particles were added to a reactive long-chain polyether toughening agent and mixed by high-speed stirring to obtain the compound toughening agent.

[0020] Preferably, the weakly alkaline buffer is a Tris buffer. The concentration of the Tris buffer is 0.04–0.08 mol / L.

[0021] Preferably, the dopamine salt comprises dopamine hydrochloride.

[0022] Preferably, the concentration of the Tris buffer solution is 0.04–0.08 mol / L. More preferably, the concentration of the Tris buffer solution is 0.06 mol / L.

[0023] Preferably, the stirring speed is 500-900 rpm, and more preferably 700 rpm.

[0024] Preferably, the number of centrifugation-dispersion cycles is 8 to 12, and more preferably 10.

[0025] Based on the same inventive concept, the present invention also provides a method for preparing the aforementioned toughened and impact-resistant epoxy resin composition, comprising the following steps: Weigh out the acid anhydride curing agent, compound toughening agent and accelerator according to the ratio, mix them in a vacuum environment and prepare a primary mixture. Epoxy resin is incorporated into the primary mixture and stirred thoroughly under vacuum to obtain a secondary mixture; the secondary mixture is then subjected to segmented curing treatment to obtain the toughened and impact-resistant epoxy resin composition.

[0026] Preferably, the ambient temperature for preparing the primary mixture is 50℃~60℃, and the vacuum degree is less than 10. - ¹ Pa.

[0027] Preferably, the segmented curing is performed sequentially at 105°C for 3 hours, 135°C for 3 hours, and 165°C for 3 hours.

[0028] Based on the same inventive concept, the present invention also provides a method for preparing fiber-reinforced epoxy resin composite, wherein a glass fiber layer is laid and compacted inside a mold cavity; a secondary mixture prepared according to the preparation method of the toughened and impact-resistant epoxy resin composition is injected into the pre-laid glass fiber mold and the resin is continuously injected; after the injection process is completed, segmented curing is performed to obtain the fiber-reinforced epoxy resin composite.

[0029] Preferably, the thickness-to-density ratio of the glass fiber in the mold is 1.1 to 1.4.

[0030] Preferably, the thickness-to-density ratio of the glass fiber is 1.3.

[0031] Based on the same inventive concept, the present invention also provides an ultra-high voltage insulation component, the insulation component comprising the fiber-reinforced epoxy resin composite material described above.

[0032] Preferably, the ultra-high voltage insulating component is an insulating tie rod for an ultra-high voltage GIS circuit breaker.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves a perfect balance between significantly improved epoxy resin toughness and stable processing performance by introducing the core technical feature of polydopamine-encapsulated liquid polysulfide rubber and reactive long-chain polyether toughening agent, resulting in significant and logically closed-loop beneficial technical effects.

[0034] Firstly, addressing the technical pain points of liquid polysulfide rubber—its excellent toughening effect but extremely high viscosity and tendency to agglomerate, and the fact that its thiol groups readily react with epoxy groups at high temperatures, leading to a dramatic increase in system viscosity and a severely shortened processing window—this invention employs the technical feature of encapsulating liquid polysulfide rubber with polydopamine. The principle is that polydopamine polymerizes on the surface of polysulfide rubber to form an encapsulation layer. This layer constitutes a physical barrier, effectively isolating the direct contact between thiol groups and epoxy groups, thereby significantly slowing down the reaction rate at high temperatures. Simultaneously, the encapsulation process transforms the high-viscosity liquid rubber into a uniform solid particle structure, breaking the original intermolecular entanglement and agglomeration tendency. The technical effect of this feature is that it fully preserves the highly efficient toughening properties of polysulfide rubber's long-chain flexible segments in absorbing impact energy, while completely solving the problems of premature crosslinking and viscosity spikes within the impregnation window caused by directly introducing polysulfide rubber. This ensures rapid diffusion and full impregnation of the adhesive solution in glass fibers, avoiding fatal defects such as insufficient adhesive and porosity in cast products.

[0035] Secondly, to address the potential initial viscosity fluctuations and limited toughening dimension caused by simply introducing encapsulated polysulfide rubber, this invention incorporates a reactive long-chain polyether toughening agent. The principle is that the hydroxyl groups in the long-chain polyether can directly participate in the curing and crosslinking reaction of the epoxy resin, introducing flexible chain segments into the crosslinking network through chemical bonding. Furthermore, the liquid polyether itself possesses excellent dilution and viscosity-reducing effects. This technical feature produces a dual effect: on the one hand, the reactive polyether further enhances the flexibility and impact resistance of the crosslinking network through chemical bonding, achieving synergistic toughening with the polysulfide rubber; on the other hand, its significant viscosity-reducing effect precisely offsets the viscosity increase caused by the introduction of encapsulated particles, resulting in a high degree of overlap between the initial viscosity and viscosity-temperature curves of the compounded system and the original control group without the added toughening agent, ensuring that the original insulating tie rod injection process requires no modification.

[0036] Finally, by optimizing the mass ratio of polydopamine-encapsulated liquid polysulfide rubber to reactive long-chain polyether toughening agent to 1:1.5–1:3, the optimal balance between toughening synergy and viscosity adjustment was achieved. The comprehensive technical effect of this feature is that, while maintaining low viscosity, a long processing window, and completely unchanged insulation and heat resistance properties, the elongation at break and impact strength of the cured product are significantly improved. This high toughness is effectively transferred to the fiber-reinforced epoxy resin composite material as a whole, significantly reducing the risk of mechanical fatigue and flashover failure in the insulating tie rod under frequent breaking conditions, thus achieving a logical closed loop of performance improvement and process adaptation. Attached Figure Description

[0037] Figure 1 This is a SEM image of the crosslinked network of the toughened and impact-resistant epoxy resin composition of Example 3 of the present invention; Figure 2 This is a SEM image of the crosslinked network of the toughened and impact-resistant epoxy resin composition of Example 4 of the present invention; Figure 3 This is a SEM image of the epoxy resin crosslinking network in Comparative Example 1. Figure 4 This is a SEM image of the epoxy resin crosslinking network in Comparative Example 2; Figure 5 This is a SEM image of the epoxy resin crosslinking network in Comparative Example 3. Detailed Implementation

[0038] The technical solution will be further described below with reference to the accompanying drawings and specific embodiments to aid in understanding the content of the present invention. In the following embodiments, the 'thickness-to-density ratio' refers to the ratio of the natural total thickness of the laid reinforcing fiber layer to the designed thickness of the mold cavity, and is calculated as: single-layer fiber cloth thickness × number of layers laid / mold cavity thickness. In the present invention, by controlling the thickness-to-density ratio between 1.1 and 1.4, the laid fiber layer is subjected to moderate physical compression within the mold cavity during mold closing or vacuum bag sealing. This pre-set compression state is beneficial in two ways: firstly, it helps to tightly compact the fiber layer and eliminate excess air between layers, preventing air bubbles or glue gaps during subsequent glue injection; secondly, it can effectively improve the density of the fiber layer and the fiber volume content of the final product, thereby ensuring the mechanical strength of the insulating component.

[0039] Example 1 Example 1 This embodiment provides a compound toughening agent, including polydopamine-encapsulated liquid polysulfide rubber and a reactive long-chain polyether toughening agent; the polydopamine-encapsulated liquid polysulfide rubber has a polydopamine coating structure.

[0040] The mass ratio of the polydopamine-encapsulated liquid polysulfide rubber to the reactive long-chain polyether toughening agent is 1:1.5 to 1:3.

[0041] The compound toughening agent is obtained by mixing polydopamine-modified liquid polysulfide rubber with a reactive long-chain polyether toughening agent, and is a black suspension, wherein: Reactive long-chain polyether toughening agents can be used directly in commercially available systems to reduce system viscosity and impart flexibility and toughness to the crosslinked network.

[0042] The steps for polydopamine-coated polysulfide rubber are as follows: Liquid polysulfide rubber with a molecular weight of 1000-4000 is introduced into dopamine hydrochloride under the action of 0.06 mol / L Tris buffer. After stirring evenly, sodium hydroxide is added to adjust the environment to weak alkalinity (8-9). After stirring at 700 rpm, centrifugation-dispersion cycle is performed to ensure that unreacted dopamine hydrochloride is removed. After freeze-drying, polydopamine-coated polysulfide rubber particles are obtained.

[0043] The reactive long-chain polyether toughening agents include QS-N, QS-210B and QS-VA3.

[0044] The low molecular weight liquid polysulfide rubber is designated as JLY-121 or JLY-124.

[0045] Based on the same inventive concept, the present invention also provides a method for preparing a compound toughening agent, comprising the following steps: A rubber dispersion was prepared by dispersing liquid polysulfide rubber in an aqueous solution containing Tris buffer. Dopamine hydrochloride was added to the rubber dispersion and mixed well to obtain a mixture; An alkaline regulator was added to the mixture to adjust the pH of the system to 8-9, and the reaction was stirred to obtain a reaction solution. The reaction solution is centrifuged and the lower precipitate is collected. Deionized water is added to the precipitate to redisperse it. The centrifugation-dispersion operation is repeated multiple times to obtain the separated precipitate. The separated precipitate was freeze-dried to prepare polydopamine-encapsulated liquid polysulfide rubber particles. The polydopamine-encapsulated liquid polysulfide rubber particles were added to a reactive long-chain polyether toughening agent and mixed by high-speed stirring to obtain the compound toughening agent.

[0046] The adsorption and reactivity of polysulfide rubber were adjusted by encapsulating it with polydopamine under alkaline conditions. Using deionized water as the solvent, Tris as the buffer solution, and dopamine hydrochloride as the modifying filler, the pH of the solution was adjusted to 8-9 (preferably 8.5) with sodium hydroxide. Polymerization modification with dopamine hydrochloride was carried out at 700 rpm. After 8-10 (preferably 10) centrifugation-dispersion cycles, the lower precipitate was freeze-dried to obtain a black polydopamine-encapsulated liquid polysulfide rubber powder. The polydopamine-encapsulated liquid polysulfide rubber powder was then stirred with a long-chain polyether toughening agent at high speed to obtain a black suspension of the compound toughening agent.

[0047] A typical implementation process is as follows: (1) Pour the corresponding proportion of polysulfide rubber into deionized water, prepare the corresponding Tris buffer solution, add the corresponding proportion of dopamine hydrochloride after mixing, stir evenly and then add sodium hydroxide particles, adjust the pH of the solution to 8.5 and stir at 700 rpm for 24 hours to ensure the polymerization and encapsulation of dopamine hydrochloride.

[0048] (2) After centrifuging the solution at 12000 rpm for 10 min, take the lower precipitate and add deionized water again. Stir at 700 rpm to make up one cycle. Perform 10 cycles in total. Freeze-dry the obtained lower precipitate.

[0049] (3) The black powder obtained by freeze-drying is poured into the liquid of reactive long-chain polyether diluent according to the mass ratio, and stirred rapidly at 8000 rpm for 20 min until it reaches a suspension state. The compound toughening agent is obtained.

[0050] The purpose of the compound toughening agent described in this invention is to introduce liquid polysulfide rubber with good toughening effect into the epoxy resin crosslinking system, ensuring that it still has good toughening effect, stable temperature-range viscosity-temperature characteristics, and a stable processing window after introduction, so as to meet the needs of the casting process of insulating tie rods. Based on this, this invention uses dopamine hydrochloride to encapsulate the polysulfide rubber particles. On the one hand, this reduces the agglomeration of polysulfide rubber dispersed in epoxy resin. On the other hand, it reduces the main technical difficulties caused by the rapid increase in viscosity and the increase in injection defects due to the compression processing window caused by the reaction between polysulfide rubber and epoxy resin curing agent (anhydride). This improves the processability of epoxy resin while retaining the toughening effect of polysulfide rubber.

[0051] The main functions of adding reactive long-chain polyether toughening agents in compounding include reducing the initial viscosity of the epoxy resin system after the introduction of polysulfide rubber, adjusting the viscosity-temperature curve trend to be as close as possible to the control group of epoxy resin formulation system without added toughening agents, and ensuring that the original insulating tie rod injection process remains unchanged. Preliminary tests show that reactive long-chain polyether toughening agents can further improve the toughness of epoxy resin, while non-reactive diluents will lead to a decrease in toughness and tensile strength.

[0052] In summary, this invention addresses the specific process requirements of adhesive injection for insulating tie rods and the objective difficulty of improving the brittleness of existing epoxy resin formulations. It designs a compound toughening system that balances toughening requirements and processing technology, improves the dispersion performance of polysulfide rubber in epoxy resin, slows down the reaction rate, and significantly improves the elongation at break and impact resistance of epoxy resin and fiber-reinforced epoxy resin composites using this additive. It has significant technical advantages and application value.

[0053] Example 2 Based on the same inventive concept, this invention also provides a toughened and impact-resistant epoxy resin composition, belonging to an epoxy resin formulation system prepared by compounding toughening additives, using the following curing mixing system in parts by weight, the components and proportions of which include: 100 parts epoxy resin; 70-100 parts of acid anhydride curing agent; The compound toughening agent is added in a ratio of 1-15 parts; Accelerator 0.125–1.25 parts; Preferably, the addition ratio of the compound toughening agent is 5 to 10 parts, wherein the mass ratio of the long-chain polyether diluent to the polydopamine-coated polysulfide rubber is 1:2.

[0054] Preferably, the epoxy resin includes bisphenol A type epoxy resin E-51 or CLP-128.

[0055] Preferably, the promoter comprises 1,2-dimethylimidazole.

[0056] Preferably, the curing agent is methyl nadic anhydride, and the amount added is 85 parts.

[0057] A typical implementation process is as follows: (1) Prepare the anhydride curing agent, compound toughening agent and accelerator according to the ratio described above, and mix them thoroughly in a water bath at a vacuum environment of 60°C in a ratio of 85:7.5:0.5 to make a primary mixture.

[0058] (2) Mix epoxy resin and primary mixture at a ratio of 100:93 at 85°C to obtain secondary mixture. In a vacuum environment, inject the secondary mixture from the bottom of the mold upwards. After injection, let stand for 2-3 hours, heat to 105°C and cure for 3 hours, then at 135°C and cure for 3 hours, and finally at 165°C and cure for 3 hours. Take out the sample.

[0059] This invention significantly improves the elongation at break and impact resistance of epoxy resin without affecting its electrical, insulating, and processing properties, and enhances its long-term stability. It is applicable to fields such as epoxy resin casting for insulating tie rods and has a wide range of applications.

[0060] Example 3 Based on the same inventive concept, this embodiment provides a method for preparing the toughened and impact-resistant epoxy resin composition described in Example 2, the method comprising the following steps: Prepare epoxy resin, acid anhydride curing agent, compound toughening agent and accelerator according to the proportions described in Example 2; Anhydride curing agent, compound toughening agent and accelerator are mixed in a vacuum environment at 70°C to form a primary mixture; The epoxy resin and the primary mixture are mixed in a vacuum environment using a dispensing machine to obtain the secondary mixture; The secondary mixture is injected into the mold from below, and after segmented curing, the toughened and impact-resistant epoxy resin composition is obtained.

[0061] Preferably, the vacuum environment includes mixing within a vacuum casting machine.

[0062] In this embodiment, the selected compound toughening agent is a suspension formed by high-speed stirring of liquid polysulfide rubber coated with polydopamine and reactive long-chain polyether toughening agent. The modification method of liquid polysulfide rubber coated with polydopamine is to polymerize dopamine hydrochloride and encapsulate it to form black particles. The preferred polysulfide rubber is liquid low molecular weight polysulfide rubber JLY-121, JLY-124, etc.

[0063] The reactive long-chain polyether toughening agent is QS-N, QS-210B, or QS-VA3.

[0064] The mass ratio of reactive long-chain polyether toughening agent to polydopamine-encapsulated liquid polysulfide rubber in the compound toughening agent is 1.5:1 to 3:1, preferably 2:1. The content of the compound toughening agent is 1% to 15% of the epoxy resin, preferably 5% to 10%. It should be noted that this scheme does not disregard other technical parameters of the epoxy resin, but rather aims to improve its insulation and heat resistance properties as much as possible while ensuring the stability of the system's viscosity-temperature profile and processing window.

[0065] A typical but non-limiting method for preparing a toughened and impact-resistant epoxy resin composition includes the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0066] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0067] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was removed and dissolved in deionized water to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0068] (4) Pour 20g of polydopamine-coated polysulfide rubber into 40mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent. (The density of the toughening agent is 1.05g / cm3, which was calculated based on the mass ratio at the time.) (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form component B. In a vacuum environment at 85°C, inject epoxy resin (component A) and component B into the mold in a ratio of 100:93.

[0069] (6) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours. Take out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0070] This invention primarily targets epoxy resin formulations for insulating tie rods. It addresses the inherent brittleness of epoxy resins used in insulating tie rods and the demanding operational environment requiring tens of thousands of live-line breaking cycles. The invention was developed while retaining the original formulation's low viscosity and long processing window. The polysulfide rubber, which offers the best toughening effect, is modified to reduce agglomeration and slow down the reaction rate during the injection molding window, eliminating complex filtration and reaction conditions. After using compound toughening additives, the epoxy resin formulation exhibits minimal viscosity variation across the temperature range, allowing for continued production while maintaining the original injection molding process. The finished epoxy resin exhibits significantly improved toughness and impact resistance, enhancing its fracture toughness and long-term performance.

[0071] Example 4 This embodiment provides a method for preparing a toughened and impact-resistant epoxy resin composition, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0072] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir, add 3 g of dopamine hydrochloride, mix and stir at 700 rpm, add NaOH powder to adjust the pH to 8.5, and stir the resulting solution at 700 rpm for 24 h.

[0073] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0074] (4) Pour 20g of polydopamine-coated polysulfide rubber into 40mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0075] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B. In a vacuum environment at 85°C, inject epoxy resin (material A) and material B in a ratio of 100:90.5 into the mold.

[0076] (6) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours before taking out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0077] Example 5 This embodiment provides a method for preparing a toughened and impact-resistant epoxy resin composition, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0078] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0079] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0080] (4) Pour 20g of polydopamine-coated polysulfide rubber into 40mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0081] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:10:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form component B. In a vacuum environment at 85°C, inject epoxy resin (component A) and component B in a ratio of 100:95.5 into the mold.

[0082] (6) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours before taking out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0083] Example 6 This embodiment provides a method for preparing a toughened and impact-resistant epoxy resin composition, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0084] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0085] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0086] (4) Pour 20g of polydopamine-coated polysulfide rubber into 60mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0087] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B. In a vacuum environment at 85°C, inject epoxy resin (material A) and material B into the mold in a ratio of 100:93.

[0088] (6) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours before taking out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0089] Example 7 This embodiment provides a method for preparing a toughened and impact-resistant epoxy resin composition, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0090] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0091] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0092] (4) Pour 20g of polysulfide rubber coated with acid anhydride curing agent polydopamine into 60mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain compound toughening agent.

[0093] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B. In a vacuum environment at 85°C, inject epoxy resin (material A) and material B in a ratio of 100:90.5 into the mold.

[0094] (6) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours before taking out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0095] Example 8 This embodiment provides a method for preparing a toughened and impact-resistant epoxy resin composition, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0096] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0097] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0098] (4) Pour 20g of polydopamine-coated polysulfide rubber into 60mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0099] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:10:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form component B. In a vacuum environment at 85°C, inject epoxy resin (component A) and component B in a ratio of 100:95.5 into the mold.

[0100] (6) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours before taking out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0101] Example 9 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: Prepare epoxy resin, acid anhydride curing agent, compound toughening agent and accelerator according to the proportions described in Example 3.

[0102] Anhydride curing agent, compound toughening agent and accelerator are mixed in a vacuum environment at 50°C to form a primary mixture; The epoxy resin and the primary mixture are injected into a vacuum environment using a dispensing machine to obtain a secondary mixture. The secondary mixture is injected into the mold through the injection port at the bottom of the mold. The mold is pre-laid with glass fiber cloth of equal area and certain thickness. During the injection process, an 85°C vacuum environment is maintained. The flow rate of the glue at the top of the mold is detected. The injection is completed when the flow rate at the injection port is consistent and there are no air bubbles inside. After segmented curing, the fiber-reinforced epoxy resin composite material of the compound toughening agent system is obtained.

[0103] In this embodiment, the raw materials, proportions, and preferred conditions are all the same as those described in Example 3, wherein the glass fiber cloth is alkali-free glass fiber cloth, and the fiber laying thickness-to-density ratio is 1.1 to 1.4, preferably 1.3.

[0104] A typical but non-limiting method for preparing fiber-reinforced epoxy resin composites includes the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0105] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0106] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0107] (4) Pour 20g of polydopamine-coated polysulfide rubber into 40mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0108] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0109] Fiberglass cloth is laid into the mold at a thickness-to-density ratio of 1.3. The mold containing the fiberglass is then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold is then covered. Epoxy resin (component A) and component B are mixed at a ratio of 100:93 and injected into the mold under vacuum at 85°C.

[0110] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, let the sample stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours before removing the sample. Cut the sample to the shape required for standard testing and test it according to national standards.

[0111] This embodiment corresponds to the glue injection process of the insulating tie rod, and is used to verify that, under the premise that the glue injection process conditions of the insulating tie rod remain unchanged, the optimized epoxy resin formulation system is reflected in the fiber-reinforced epoxy resin composite material.

[0112] Example 10 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0113] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir, add 3 g of dopamine hydrochloride, mix and stir at 700 rpm, add NaOH powder to adjust the pH to 8.5, and stir the resulting solution at 700 rpm for 24 h.

[0114] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0115] (4) Pour 20g of polydopamine-coated polysulfide rubber into 40mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0116] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0117] Fiberglass cloth is laid into the mold at a thickness-to-density ratio of 1.2. The mold containing the fiberglass is then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold is then covered. Epoxy resin (component A) and component B are mixed at a ratio of 100:93 and injected into the mold under vacuum at 85°C.

[0118] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, let it stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Take out the sample. Cut the sample to the shape required for standard testing and test it according to the national standard.

[0119] Example 11 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0120] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0121] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0122] (4) Pour 20g of polydopamine-coated polysulfide rubber into 40mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0123] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0124] Fiberglass cloth is laid into the mold at a thickness-to-density ratio of 1.2. The mold containing the fiberglass is then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold is then covered. Epoxy resin (component A) and component B are mixed at a ratio of 100:93 and injected into the mold under vacuum at 85°C.

[0125] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, allow the sample to stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Remove the sample and cut it into the shape required for standard testing. Test according to national standards.

[0126] Example 12 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0127] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0128] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0129] (4) Pour 20g of polydopamine-coated polysulfide rubber into 60mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0130] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0131] Fiberglass cloth is laid into the mold at a thickness-to-density ratio of 1.2. The mold containing the fiberglass is then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold is then covered. Epoxy resin (component A) and component B are mixed at a ratio of 100:93 and injected into the mold under vacuum at 85°C.

[0132] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, let it stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Take out the sample. Cut the sample to the shape required for standard testing and test it according to the national standard.

[0133] Example 13 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0134] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0135] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0136] (4) Pour 20g of polydopamine-coated polysulfide rubber into 60mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0137] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0138] Fiberglass cloth was laid into the mold at a thickness-to-density ratio of 1.2. The mold containing the fiberglass cloth was then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold was then covered. Under a vacuum environment at 85°C, epoxy resin (component A) and component B were mixed at a ratio of 100:90.5 and injected into the mold.

[0139] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, allow the sample to stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Remove the sample and cut it into the shape required for standard testing. Test according to national standards.

[0140] This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: Example 14 (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0141] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0142] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0143] (4) Pour 20g of polydopamine-coated polysulfide rubber into 60mL of QS-VA3 liquid long-chain polyether toughening agent and stir at 12000rpm for 20min to obtain the compound toughening agent.

[0144] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:10:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0145] Fiberglass cloth was laid into the mold at a thickness-to-density ratio of 1.2. The mold containing the fiberglass cloth was then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold was then covered. Under a vacuum environment at 85°C, epoxy resin (component A) and component B were mixed at a ratio of 100:95.5 and injected into the mold.

[0146] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, allow the sample to stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Remove the sample and cut it into the shape required for standard testing. Test according to national standards.

[0147] Example 15 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: (1) Mix 20g of JLY-121 polysulfide rubber with a molecular weight of 1000 with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0148] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0149] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0150] (4) Pour 20g of polydopamine-coated polysulfide rubber into 28.6mL of QS-VA3 liquid long-chain polyether toughening agent. The toughening agent has a density of 1.05g / cm³, corresponding to a mass of 30g. The mass ratio of polysulfide rubber to polyether is 1:1.5. Stir at 12000rpm for 20min to obtain the compound toughening agent.

[0151] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 70:2.5:0.125 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0152] Fiberglass cloth is laid into the mold at a thickness-to-density ratio of 1.1. The mold containing the fiberglass is then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold is then covered. Epoxy resin (component A) and component B are mixed at a ratio of 100:72.625 and injected into the mold under vacuum at 85°C.

[0153] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, let it stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Take out the sample. Cut the sample to the shape required for standard testing and test it according to the national standard.

[0154] Example 16 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: (1) Mix 20g of liquid polysulfide rubber with a molecular weight of 2500 with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0155] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0156] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0157] (4) Pour 20g of polydopamine-coated polysulfide rubber into 42.9mL of QS-VA3 liquid long-chain polyether toughening agent. The toughening agent has a density of 1.05g / cm³, corresponding to a mass of 45g. The mass ratio of polysulfide rubber to polyether is 1:2.25. Stir at 12000rpm for 20min to obtain the compound toughening agent.

[0158] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 80:5:0.25 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0159] Fiberglass cloth is laid into the mold at a thickness-to-density ratio of 1.25. The mold containing the fiberglass is then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold is then covered. Epoxy resin (component A) and component B are mixed at a ratio of 100:93.125 and injected into the mold under vacuum at 85°C.

[0160] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, let it stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Take out the sample. Cut the sample to the shape required for standard testing and test it according to the national standard.

[0161] Example 17 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites, the method comprising the following steps: (1) Mix 20g of JLY-124 polysulfide rubber with a molecular weight of 4000 with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0162] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0163] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-coated polysulfide rubber.

[0164] (4) Pour 20g of polydopamine-coated polysulfide rubber into 57.1mL of QS-VA3 liquid long-chain polyether toughening agent. The toughening agent has a density of 1.05g / cm³, corresponding to a mass of 60g. The mass ratio of polysulfide rubber to polyether is 1:3. Stir at 12000rpm for 20min to obtain the compound toughening agent.

[0165] (5) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 90:12.5:1.25 and stir at 700 rpm in a vacuum environment at 50°C to form material B.

[0166] Fiberglass cloth is laid into the mold at a thickness-to-density ratio of 1.4. The mold containing the fiberglass is then placed in an oven at 85°C and dried for 2 hours to remove moisture from the fiberglass. The mold is then covered. Epoxy resin (component A) and component B are mixed at a ratio of 100:113.75 and injected into the mold under vacuum at 85°C.

[0167] (6) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, let it stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Take out the sample. Cut the sample to the shape required for standard testing and test it according to the national standard.

[0168] Example 18 This embodiment provides a method for preparing fiber-reinforced epoxy resin composites. JLY-124 liquid polysulfide rubber with a molecular weight of 4000 is encapsulated with polydopamine and freeze-dried. 20g of the encapsulated particles are then added to 57.1mL of QS-VA3 liquid long-chain polyether toughening agent (corresponding to 60g) and stirred at high speed to obtain a compound toughening agent. A mixture of anhydride curing agent, compound toughening agent, and accelerator at a mass ratio of 100:12.5:1.25 is prepared under vacuum at 50°C to form component B. Epoxy resin (component A) and component B are injected into a mold lined with alkali-free glass fiber cloth of a thickness-to-density ratio of 1.4 under vacuum at 85°C at a ratio of 100:113.75. After injection and confirmation of no air bubbles, the mixture is sequentially cured at 105°C for 3 hours, 135°C for 3 hours, and 165°C for 3 hours to obtain the fiber-reinforced epoxy resin composite. Samples are then cut and tested for performance.

[0169] Example 19 Based on the same inventive concept, this embodiment provides a fiber-reinforced epoxy resin composite, comprising the toughened and impact-resistant epoxy resin composition and glass fiber.

[0170] Example 20 Based on the same inventive concept, this invention also provides an ultra-high voltage insulation component, which is prepared by the method described above for the fiber-reinforced epoxy resin composite. The fiber-reinforced epoxy resin composite of this invention employs an integrated vacuum casting molding process. Specifically, a custom mold is designed according to the actual structural dimensions of the ultra-high voltage insulation component (such as an insulating tie rod). After a glass fiber layer is pre-laid and compacted inside the mold cavity, a secondary mixed adhesive is directly injected and cured in situ. Therefore, the final product obtained by this method after curing in the mold and demolding directly constitutes the ultra-high voltage insulation component itself, whose macroscopic shape and dimensions meet service requirements, without requiring additional secondary machining of the molded composite material.

[0171] Preferably, the ultra-high voltage insulation component includes an insulating tie rod for an ultra-high voltage GIS circuit breaker. In manufacturing the insulating tie rod, glass fiber is laid in a slender tubular mold according to the axial force requirements of the tie rod. After resin injection, it is cured in sections, ultimately forming a finished insulating tie rod with high toughness, impact resistance, and no internal defects.

[0172] Ultra-high voltage (UHV) insulating tie rods must withstand extremely high instantaneous tensile or compressive loads during switch-off operations and are repeatedly subjected to mechanical impacts during frequent closing operations. In the composite system of this invention, continuous glass fiber, as a reinforcing skeleton, provides extremely high axial tensile and flexural strength; while the epoxy resin matrix modified with the toughening additives of this invention exhibits significantly improved elongation at break and impact strength. The high-toughness matrix and high-strength fiber form a synergistic effect: when the tie rod is subjected to mechanical impact or load disturbance, the flexible cross-linked network and polysulfide rubber particles can effectively absorb impact energy, inducing crazes or shear bands, thereby preventing the initiation and rapid propagation of cracks. This completely overcomes the fatal defects of traditional pure epoxy resin systems, which are brittle and prone to debris and cracks due to mechanical fatigue during tens of thousands of live-line switching operations, ensuring the structural integrity and mechanical stability of insulating components during long-term service.

[0173] In ultra-high voltage and strong electric field environments, insulating components not only need to possess high intrinsic insulation performance, but also must be free of internal pores or defects to prevent partial discharge. Firstly, the epoxy resin system, glass fiber, and compounded toughening agents selected in this invention all possess excellent dielectric properties, resulting in a composite material with extremely high dielectric strength (up to 50 kV / mm and above) and volume resistivity (10¹⁰). 6 (Ohm·cm level), with a large insulation margin. Secondly, and more importantly, this invention slows down the reaction rate by encapsulating polysulfide rubber with polydopamine, and combined with the viscosity-reducing effect of reactive long-chain polyethers, allows the resin solution to maintain an extremely low initial viscosity while possessing a processing window of 2-3 hours. This process characteristic ensures that the high-viscosity resin solution can completely expel air bubbles and fully impregnate the dense glass fiber layer under vacuum, eliminating defects such as insufficient resin and porosity inside the casting body. The dense and defect-free internal structure avoids internal breakdown discharge caused by localized electric field concentration, while the high-toughness surface is less prone to mechanical debris adhesion, thus effectively preventing surface flashover faults.

[0174] In summary, the fiber-reinforced epoxy resin composite of the present invention achieves a simultaneous leap in mechanical impact resistance and electrical insulation performance through the deep coupling of 'high-strength fiber + high-toughness insulating matrix + defect-free vacuum casting molding', making it an ideal material and molding solution for ultra-high voltage insulation components.

[0175] Comparative Example 1 (1) Untreated JLY-121 polysulfide rubber was used directly as a toughening agent.

[0176] (2) Mix the acid anhydride curing agent, toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form component B. In a vacuum environment at 85°C, mix epoxy resin (component A) and component B in a ratio of 100:93 and inject the adhesive in a vacuum environment at 85°C.

[0177] (3) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours. Take out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0178] Comparative Example 2 (1) Long-chain polyether toughening agent QS-VA3 was used directly as a toughening agent for later use.

[0179] (2) Mix the acid anhydride curing agent, toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form component B. In a vacuum environment at 85°C, mix epoxy resin (component A) and component B in a ratio of 100:93 and inject the adhesive in a vacuum environment at 85°C.

[0180] (3) After the adhesive is applied, let it stand for 2-3 hours, then cure it at 105℃ for 3 hours, then at 135℃ for 3 hours, and finally at 165℃ for 3 hours before taking out the sample. Cut the sample to the shape required for standard testing and test it according to the national standard.

[0181] Comparative Example 3 (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0182] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution. Mix and stir the solution obtained in step (1). Add 3 g of dopamine hydrochloride. After mixing, stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0183] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-encapsulated polysulfide rubber as a compound toughening agent.

[0184] (4) Mix the acid anhydride curing agent, compound toughening agent and accelerator in a ratio of 85:7.5:0.5 and stir at 700 rpm in a vacuum environment at 50°C to form component B. In a vacuum environment at 85°C, mix epoxy resin (component A) and component B in a ratio of 100:93 and inject the adhesive in a vacuum environment at 85°C.

[0185] (5) After the adhesive is applied, let it stand for 2-3 hours, then heat it to 105℃ and cure it for 3 hours, then heat it to 135℃ and cure it for 3 hours, and finally heat it to 165℃ and cure it for 3 hours before taking out the sample. Cut the sample into the shape required for standard testing and test it according to the national standard.

[0186] Comparative Example 4 (1) Untreated JLY-121 polysulfide rubber was used directly as a toughening agent.

[0187] (2) Mix the anhydride curing agent, toughening agent, and accelerator in a ratio of 85:5:0.5, and stir at 700 rpm under vacuum at 50°C to form component B. Lay the fiberglass cloth into the mold at a thickness-to-density ratio of 1.3. Place the mold containing the fiberglass into an oven at 85°C and dry for 2 hours to remove the moisture contained in the fiberglass. Cover the mold. Under vacuum at 85°C, inject epoxy resin (component A) and component B into the mold in a ratio of 100:93.

[0188] (3) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, let the sample stand in a vacuum environment for 2-3 hours, then cure it at 105℃ for 3 hours, then at 135℃ for 3 hours, and finally at 165℃ for 3 hours. Cut the sample into the shape required for standard testing and test it according to national standards.

[0189] Comparative Example 5 (1) Long-chain polyether toughening agent QS-VA3 was used directly as a toughening agent for later use.

[0190] (2) Mix the anhydride curing agent, toughening agent, and accelerator in a ratio of 85:7.5:0.5, and stir at 700 rpm under vacuum at 50°C to form component B. Lay the fiberglass cloth into the mold at a thickness-to-density ratio of 1.3. Place the mold containing the fiberglass into an oven at 85°C and dry for 2 hours to remove the moisture contained in the fiberglass. Cover the mold. Under vacuum at 85°C, inject epoxy resin (component A) and component B into the mold in a ratio of 100:93.

[0191] (3) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, allow the sample to stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Remove the sample and cut it into the shape required for standard testing. Test according to national standards.

[0192] Comparative Example 6 (1) Mix 20g of JLY-121 polysulfide rubber with 400mL of deionized water and stir at 12000rpm for 10min using a high-speed mixer for later use.

[0193] (2) Add Tris to 100 mL of deionized water to prepare a 0.06 mol / L buffer solution, mix it with the solution obtained in step (1) and stir. Add 3 g of dopamine hydrochloride, mix and stir at 700 rpm. Add NaOH powder to adjust the pH to 8.5. Stir the resulting solution at 700 rpm for 24 h.

[0194] (3) The obtained solution was centrifuged at 12000 rpm for 10 min. Each time, the precipitate was taken off and redissolved to 500 mL as one cycle. A total of 10 cycles were performed. The obtained powder was freeze-dried for 24 h to obtain polydopamine-encapsulated polysulfide rubber as a compound toughening agent.

[0195] (4) Mix the anhydride curing agent, compound toughening agent, and accelerator in a ratio of 85:7.5:0.5, and stir at 700 rpm under vacuum at 50°C to form component B. Lay the fiberglass cloth into the mold at a thickness-to-density ratio of 1.3. Place the mold containing the fiberglass into an oven at 85°C and dry for 2 hours to remove the moisture contained in the fiberglass. Cover the mold. Under vacuum at 85°C, inject epoxy resin (component A) and component B into the mold in a ratio of 100:93.

[0196] (5) Monitor the flow rate of epoxy resin at the bottom injection port and the top outlet. Stop injection when the flow rates are consistent and there are no air bubbles inside. After injection, allow the sample to stand in a vacuum environment for 2-3 hours, then heat to 105℃ for 3 hours, then heat to 135℃ for 3 hours, and finally heat to 165℃ for 3 hours. Remove the sample and cut it into the shape required for standard testing. Test according to national standards.

[0197] Table 1 Comparison of key technical parameters of materials (without glass fiber reinforcement) prepared in Examples 3-8 and Comparative Examples 1-3 of the present invention

[0198] Table 2 Comparison of key technical parameters of materials (with glass fiber reinforcement) obtained in Examples 9-18 and Comparative Examples 4-7 of the present invention

[0199] Table 3. Comparison of the viscosity of the mixture at room temperature, 85°C, and after standing for 3 hours for the materials prepared in Examples 3-8 and Comparative Examples 1-4 of this invention.

[0200] The main reason for the lack of data in Comparative Example 4 in Table 2 is that the epoxy resin viscosity is too high to penetrate the entire glass fiber, resulting in improper curing, and therefore no technical parameters are available.

[0201] The impact strength of Comparative Examples 1-7 and Examples 9-18 in Tables 1 and 2 was not measured because the impact strength of the fiber-reinforced materials exceeded the range of the experimental equipment, and the laboratory equipment could not penetrate them.

[0202] As shown in Table 1, comparing Examples 3, 4, and 5, the mechanical properties of the materials (tensile strength, elongation at break, flexural strength, impact strength, etc.) showed a significant improvement compared to Comparative Example 1 (the traditional technical route without any additives). This demonstrates that the epoxy resin material modified with compound toughening additives can significantly improve the toughness of the cured epoxy resin without changing the insulation performance, providing greater margin for electrical equipment manufacturing. Comparing Examples 6, 7, and 8, the reduction in the content of polysulfide rubber in the compound toughening additives significantly affects the final improvement in the mechanical properties of the cured epoxy resin. This demonstrates that polysulfide rubber has superior toughening and impact resistance compared to traditional long-chain polyether toughening agents. This conclusion is reflected in the parameter differences between Comparative Examples 2 and 3. The main reason for the significant increase in viscosity after prolonged standing in Example 8 is that the curing agent, exceeding the stoichiometric ratio of the chemical reaction, still triggered a small amount of crosslinking, leading to an increase in system viscosity. As shown in Tables 1 and 2, Examples 9-18, compared to Examples 3-8, demonstrate that using epoxy resin based on compound toughening agents as fiber-reinforced epoxy resin composites can further improve the flexural strength and elongation at break of the material, as well as its toughness and impact resistance; while the tensile strength is mainly provided by high-strength alkali-free fiber cloth, so the change is not significant. Comparing Comparative Examples 2 and 3 with Example 3, it is demonstrated that, under the same additive content, liquid polysulfide rubber acting on epoxy resin can have superior toughening properties, significantly better than the compound toughening epoxy resin formulation system. However, based on Comparative Example 4, after introducing untreated liquid polysulfide rubber, the epoxy resin cured within the 85°C vacuum impregnation window, and the epoxy resin could not fill the entire mold cavity, exhibiting a significant defect, making Comparative Example 4 unmeasurable. Comparative Example 6, using liquid long-chain toughening agent epoxy resin for injection molding, shows a certain improvement compared to Comparative Example 1, but the improvement is significantly weaker than that of Example 9, demonstrating that the compound toughening agent has a superior toughening effect. Comparative Example 7 had defects during the glue injection process, and its product technical parameters were significantly lower than those of Example 9, thus it had no practical application value.

[0203] Table 3 shows the advantages of the compound toughening additive in terms of viscosity and processing window. Examples 3-8 show significant improvements in initial viscosity and viscosity changes during the processing window compared to Comparative Example 2, demonstrating that the polydopamine modification scheme can effectively reduce the initial viscosity of epoxy resin at room temperature and during the processing window after the introduction of liquid polysulfide rubber, ensuring the smooth progress of the impregnation process. At the same time, the polydopamine-coated granular polysulfide rubber can effectively alleviate the curing reaction with epoxy resin during the processing window, providing time for impregnation and full impregnation after the introduction of glass fiber. Therefore, this compound toughening additive modification scheme can ensure the toughening and impact resistance of polysulfide rubber as much as possible, while ensuring that the entire epoxy resin formulation system can meet the casting requirements of the insulating tie rod.

[0204] Figure 1 The SEM morphology of the crosslinked network of the toughened and impact-resistant epoxy resin composition prepared in Example 3 is shown. The main purpose of introducing the long-chain polyether toughening agent in this invention is to improve the compatibility between the toughening agent and the resin, and to ensure that the viscosity of the toughened and impact-resistant epoxy resin composition with added compound toughening additives and the epoxy resin system without added compound toughening additives remains as consistent as possible throughout the entire processing window. This reduces the problem of rapid viscosity increase of the mixture after adding polydopamine-coated polysulfide rubber particles, thereby ensuring that the overall processing technology of the insulating tie rod remains unchanged. The molding, injection, and compounding processes can be carried out entirely by referring to the existing equipment process flow, which meets the needs of electrical equipment design and manufacturing.

[0205] Figure 2 The SEM morphology of the crosslinked network of the toughened impact-resistant epoxy resin composition of Example 4 of the present invention is shown. Its structure is uniform and dense, and the polydopamine-encapsulated polysulfide rubber particles, acting as the toughening phase, are uniformly dispersed in the epoxy resin matrix without significant agglomeration. This uniform crosslinked network and good dispersion of the toughening phase are the microstructural basis for the excellent impact toughness of the epoxy resin system of Example 4—the uniform crosslinked network ensures the strength of the matrix, while the dispersed toughening phase effectively absorbs impact energy and avoids stress concentration. In contrast, Comparative Example 1 ( Figure 3 The epoxy resin crosslinking network of Comparative Example 2 is relatively loose, lacking the introduction of toughening phase, and exhibits a single epoxy resin crosslinking morphology, resulting in low impact toughness; Figure 4 In the cross-linked network of Comparative Example 3, polysulfide rubber particles are aggregated, and the bonding between the particles and the matrix is ​​not tight, causing local defects, reducing impact strength and affecting processing stability; Figure 5 In the cross-linked network of the particle, the toughening phase has poor dispersion and insufficient compatibility between the particles and the matrix, exhibiting a "particle-matrix" separation trend. This results in limited improvement in impact toughness and large viscosity variations within the processing window. Figure 2 and Figure 3-5The comparison clearly shows that the present invention uses polydopamine to coat polysulfide rubber particles (to improve the compatibility between the toughening phase and the matrix) and long-chain polyether toughening agent (to optimize the crosslinking network structure), making the crosslinking network of the examples more uniform and dense, and the toughening phase more evenly dispersed. In contrast, the comparative examples, which did not use the toughening additives or coating process of the present invention, have problems such as looseness, agglomeration, or poor compatibility. This verifies the technical effect of the present invention in "toughening and impact resistance".

[0206] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention.

Claims

1. A compound toughening agent, characterized in that, It includes polydopamine-encapsulated liquid polysulfide rubber and a reactive long-chain polyether toughening agent; the polydopamine-encapsulated liquid polysulfide rubber has a polydopamine coating structure.

2. The compound toughening agent according to claim 1, characterized in that, The mass ratio of the polydopamine-encapsulated liquid polysulfide rubber to the reactive long-chain polyether toughening agent is 1:1.5 to 1:

3.

3. The compound toughening agent according to claim 1, characterized in that, The liquid polysulfide rubber is a low molecular weight liquid polysulfide rubber with a molecular weight of 1000 to 4000.

4. The compound toughening agent according to claim 1, characterized in that, The reactive long-chain polyether toughening agent is selected from at least one of polyether polyols, polyether amines, or long-chain polyethers containing terminal active groups.

5. A toughened and impact-resistant epoxy resin composition, characterized in that, The composition comprises, by weight, 100 parts epoxy resin, 70-100 parts acid anhydride curing agent, 1-15 parts compound toughening agent as described in any one of claims 1-4, and 0.125-1.25 parts accelerator.

6. The toughened impact-resistant epoxy resin composition according to claim 5, characterized in that, The anhydride curing agent is methyl nadic anhydride, and the addition amount is 80-90 parts by weight; the addition amount of the compound toughening agent is 5-10 parts by weight; and the addition amount of the accelerator is 0.25-0.75 parts by weight.

7. The toughened impact-resistant epoxy resin composition according to claim 5, characterized in that, The epoxy resin is a bisphenol A type epoxy resin.

8. The toughened impact-resistant epoxy resin composition according to claim 5, characterized in that, The promoter is 1,2-dimethylimidazole or 2-propylimidazole.

9. A fiber-reinforced epoxy resin composite material, characterized in that, It includes the toughened and impact-resistant epoxy resin composition according to any one of claims 5 to 8 and glass fiber.

10. A method for preparing a compound toughening agent, characterized in that, Includes the following steps: A rubber dispersion was prepared by dispersing liquid polysulfide rubber in an aqueous solution containing a weakly alkaline buffer solution. Dopamine or dopamine salt is added to the rubber dispersion and mixed to obtain a mixture; An alkaline regulator was added to the mixture to adjust the pH of the system to 8-9, and the reaction was stirred to obtain a reaction solution. The reaction solution is centrifuged and the lower precipitate is collected. Deionized water is added to the precipitate to redisperse it. The centrifugation-dispersion operation is repeated multiple times to obtain the separated precipitate. The separated precipitate was freeze-dried to prepare polydopamine-encapsulated liquid polysulfide rubber particles. The polydopamine-encapsulated liquid polysulfide rubber particles are added to a reactive long-chain polyether toughening agent and mixed by high-speed stirring to obtain the compound toughening agent as described in any one of claims 1 to 4.

11. The method for preparing the compound toughening agent according to claim 10, characterized in that, The weakly alkaline buffer solution is a Tris buffer solution.

12. The method for preparing the compound toughening agent according to claim 11, characterized in that, The concentration of the Tris buffer solution is 0.04–0.08 mol / L.

13. The method for preparing the compound toughening agent according to claim 11, characterized in that, The dopamine salt includes dopamine hydrochloride.

14. The method for preparing the compound toughening agent according to claim 10, characterized in that, The stirring speed is 500–900 rpm.

15. The method for preparing the compound toughening agent according to claim 10, characterized in that, The number of cycles for centrifugation-dispersion is 8 to 12.

16. A method for preparing a toughened impact-resistant epoxy resin composition according to any one of claims 5 to 8, characterized in that, Includes the following steps: Weigh out the acid anhydride curing agent, compound toughening agent and accelerator according to the ratio, mix them in a vacuum environment and prepare a primary mixture. Epoxy resin is incorporated into the primary mixture, and the mixture is thoroughly stirred under vacuum to obtain a secondary mixture; The secondary mixture is subjected to segmented curing treatment to obtain the toughened and impact-resistant epoxy resin composition.

17. The method for preparing the toughened and impact-resistant epoxy resin composition according to claim 16, characterized in that, The ambient temperature for preparing the primary mixture is 50℃~60℃, and the vacuum degree is less than 10. - ¹ Pa.

18. The method for preparing the toughened and impact-resistant epoxy resin composition according to claim 16, characterized in that, The segmented curing process involves curing at 105℃ for 3 hours, at 135℃ for 3 hours, and at 165℃ for 3 hours in sequence.

19. A method for preparing a fiber-reinforced epoxy resin composite, characterized in that, The secondary mixture prepared according to any one of claims 16 to 18 is injected into a mold with a pre-laid glass fiber layer; after the injection process is completed, the segmented curing is performed to obtain the fiber-reinforced epoxy resin composite of claim 9.

20. The method for preparing the fiber-reinforced epoxy resin composite according to claim 19, characterized in that, The thickness-to-density ratio of the glass fiber layer laid in the mold is 1.1 to 1.

4.

21. The method for preparing the fiber-reinforced epoxy resin composite according to claim 20, characterized in that, The thickness-to-density ratio of the glass fiber layer laid in the mold is 1.

3.

22. An ultra-high voltage insulation component, characterized in that, Includes the fiber-reinforced epoxy resin composite as described in claim 9.

23. The ultra-high voltage insulating component according to claim 22, characterized in that, The ultra-high voltage insulating component is an insulating tie rod for ultra-high voltage GIS circuit breakers.

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