Epoxy resin material for high-pressure conduit and preparation method of epoxy resin material

Abstract

The invention relates to the technical field of high-molecular compounds, and discloses an epoxy resin material for a high-pressure conduit and a preparation method of the epoxy resin material. The preparation method comprises the following steps: preparing the following raw materials in parts by mass: 65-70 parts of bisphenol A epoxy resin; 55-60 parts of a curing agent; 0.1 to 0.2 part of an imidazole accelerant; 10 to 15 parts of a reactive diluent; and 8 to 15 parts of epoxy silicon dioxide. The diluent is prepared from N, N, N ', N'-tetraepoxypropyl-4, 4 '-diaminodiphenylmethane and ethylene glycol diglycidyl ether according to the mass ratio of 1 to (4 to 5); the curing agent comprises a polybenzimidazole curing agent, a polyethylene glycol curing agent and methyl tetrahydrophthalic anhydride in a mass ratio of (2-3): (2-3): (5-6). The epoxy resin material prepared by the invention has excellent electrical properties and mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of polymer compounds and discloses an epoxy resin material for a high-pressure conduit and a preparation method thereof. Background Art

[0002] High-voltage conduits are one of the key components of high-voltage electrical equipment. They are generally made by impregnating paper and aluminum foil with epoxy resin as glue, and then encapsulating the conductor in a specific way. At present, domestic conduits have been trial-produced for many years, but technical problems such as partial discharge and cracking have not been solved. Among them, epoxy resin material is a key component that affects its performance. There are the following problems: (1) Epoxy resin material has high viscosity and insufficient wettability, which easily leads to partial discharge; and insufficient wettability leads to poor interface performance, affecting mechanical properties; (2) Epoxy resin is a brittle material, and thermal stress cracking occurs during the curing process, which reduces the mechanical and electrical properties. The above defects make the product less practical and difficult to meet the stringent requirements of high-voltage electrical equipment.

[0003] In summary, it is of great significance to solve the above problems and develop an epoxy resin material for high-pressure catheters with high thermal stability, high strength, and low viscosity and a preparation method thereof. Summary of the Invention

[0004] The object of the present invention is to provide an epoxy resin material for high-pressure conduits and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: an epoxy resin material for high-pressure pipes, comprising the following raw materials, calculated by mass:

[0006] 65-70 parts of bisphenol A epoxy resin;

[0007] 55-60 parts of curing agent;

[0008] Imidazole accelerator 0.1~0.2 parts;

[0009] 10-15 parts of active diluent;

[0010] 8-15 parts of epoxy silica;

[0011] The curing agent comprises a polybenzimidazole curing agent, a polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of (2-3): (2-3): (5-6).

[0012] More optimally, the active diluent is N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:(4-5).

[0013] More optimally, the preparation of the polybenzimidazole curing agent includes the following steps: adding methyltetrahydrophthalic anhydride, hydroxylated polybenzimidazole and 4-dimethylaminopyridine to dimethyl sulfoxide, heating at 60-65° C. for 2-3 hours, removing the solvent under reduced pressure after cooling, and drying to obtain the polybenzimidazole curing agent.

[0014] More optimally, the polybenzimidazole curing agent comprises the following raw materials, calculated by weight: 20-30 parts of methyltetrahydrophthalic anhydride, 2-4 parts of hydroxylated polybenzimidazole, and 0.01-0.05 parts of 4-dimethylaminopyridine.

[0015] More optimally, the preparation of the hydroxylated polybenzimidazole comprises the following steps: adding polybenzimidazole to N,N-dimethylformamide, stirring uniformly under nitrogen protection, adding sodium hydride, stirring at room temperature for 20 to 24 hours, cooling to 0°C, adding 1-bromo-4-chlorobutane, stirring for 12 to 15 hours, adding excess ice water for precipitation, washing the precipitate, and drying to obtain chlorobutylated polybenzimidazole;

[0016] Add chlorobutylated polybenzimidazole to N-methylpyrrolidone, stir evenly under nitrogen protection, add N-methyl-2-hydroxyethylamine, stir at room temperature for 0.5-1 hour, heat to 80-100°C and stir for 20-30 hours, add excess water for precipitation, wash the precipitate, and dry to obtain hydroxylated polybenzimidazole.

[0017] More optimally, the chlorobutylated polybenzimidazole comprises the following raw materials, calculated by weight: 0.5-0.6 parts of polybenzimidazole, 20-30 parts of N,N-dimethylformamide, 0.1-0.15 parts of sodium hydride, and 0.05-0.06 parts of 1-bromo-4-chlorobutane;

[0018] The hydroxylated polybenzimidazole comprises the following raw materials, calculated by weight: 0.5-0.6 parts of chlorobutylated polybenzimidazole, 10-20 parts of N-methylpyrrolidone, and 1-2 parts of N-methyl-2-hydroxyethylamine.

[0019] More optimally, the preparation of the polyethylene glycol curing agent comprises the following steps:

[0020] Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran (the amount of tetrahydrofuran added is 5 to 8 times the mass of methyltetrahydrophthalic anhydride), add 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine added is 0.1 to 0.3 wt% of the methyltetrahydrophthalic anhydride), heat at 60 to 65°C for 2 to 3 hours, and remove the solvent to obtain modified polyethylene glycol monomethacrylate;

[0021] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol were sequentially added to tetrahydrofuran (the amount of tetrahydrofuran added was 5-8 times the mass of the modified polyethylene glycol monomethacrylate), and a photoinitiator (photoinitiator 1024) was added. The mixture was subjected to UV light click reaction for 1-2 hours, washed, and dried to obtain a polyethylene glycol curing agent.

[0022] More optimally, the molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:(1.5-2.5); the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is (4-4.5):1.

[0023] More optimally, the method for preparing the epoxy resin material for the high-pressure conduit is as follows: bisphenol A epoxy resin, curing agent, imidazole accelerator, and active diluent are mixed uniformly to obtain the epoxy resin material.

[0024] More optimally, the epoxy resin material curing process is: vacuum degassing, curing at 60-80°C for 0.5-1 hour, curing at 100-120°C for 1-2 hours, and curing at 130-150°C for 1-2 hours.

[0025] More optimally, the preparation steps of epoxy silica are as follows: take the silane coupling agent KH560, add it to a mixed solution of ethanol and water (the volume ratio of ethanol to water is 1:1), stir evenly, raise the temperature to 60-70°C, add silica, keep stirring for 4-6 hours, filter and dry to obtain epoxy silica; the mass ratio of the silane coupling agent KH560 to silica is (0.5-1):10; the inorganic filler has good compatibility, can relieve thermal stress, reduce the linear expansion coefficient, and reduce cracking caused by thermal stress.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are: the epoxy resin material prepared in the present application has good wettability for the paper base, effectively ensuring the electrical and mechanical properties.

[0027] The proposed solution limits the composition and content of the diluent, combining the higher molecular weight N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane with the lower molecular weight ethylene glycol diglycidyl ether. This effectively reduces the viscosity of the epoxy material, improves its wettability on the paper substrate, reduces partial discharge, and enhances electrical properties. The N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane provides crosslinking density, promoting the formation of a three-dimensional network structure, and enhancing the integrity of the crosslinked network while diluting the epoxy. The ethylene glycol diglycidyl ether effectively balances viscosity and promotes improved wettability. Furthermore, the flexible chain breaks provide toughening, inhibiting the brittleness of the epoxy resin and improving stress concentration. Together, the two diluents reduce viscosity while, through their multifunctional groups and rigid-flexible synergistic structure, addressing the performance shortcomings of traditional diluents, achieving high wettability and a high degree of crosslinking, and improving electrical and mechanical properties. However, the amount of both added needs to be controlled, otherwise it will lead to problems such as increased viscosity, excessive network cross-linking, and excessive rigidity, which will affect the overall performance.

[0028] In the scheme, acid anhydride is used as the main curing agent, and is compounded with polybenzimidazole curing agent and polyethylene glycol curing agent to synergistically and effectively form a uniform curing network, enhance the toughness and interfacial bonding strength of the material, further improve the anti-cracking performance, and promote the improvement of the mechanical properties and electrical properties of the epoxy resin material.

[0029] Anhydride curing agents effectively ensure high Tg, low shrinkage, and excellent electrical insulation, but they do not address the issue of excessive brittleness, which can easily lead to microcracking. Furthermore, anhydride curing requires a catalyst to improve the curing performance. Therefore, the introduction of polyethylene glycol curing agent utilizes its flexible chain breaks as elastic microdomains, effectively suppressing the formation of microcracking. Polybenzimidazole is also used to enhance the curing performance of the anhydride. The three components create a gradient curing process, effectively ensuring a uniform cross-linked network and suppressing curing stress and microcracking.

[0030] At the same time, the polybenzimidazole itself helps improve electrical properties and can form π-π stacking with paper-based fibers, enhancing interfacial interactions. The fluorine groups in the polyethylene glycol curing agent further optimize electrical properties. It's important to note that the relevant ratios need to be limited. Excessive amounts of benzimidazole curing agent can lead to reduced toughness and excessive viscosity. Excessive amounts of polyethylene glycol curing agent can dilute the crosslinking density due to the long chain structure, resulting in a loose cured network and reduced performance.

[0031] In summary, this solution effectively achieves a uniform cross-linked network through the limitation of the curing agent, improves curing stress and microcrack defects, significantly reduces the risk of partial discharge, and improves anti-cracking performance; thereby improving electrical and mechanical properties and ensuring applicability. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0033] It should be noted that the raw materials involved in the present invention are purchased from manufacturers without any special restrictions, and illustratively include: bisphenol A epoxy resin (base resin EPON828); imidazole accelerator (1-methylimidazole); polybenzimidazole (Celazole PBI U-60); N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane (CAS: 28768-32-3); silicon dioxide (N-03, Yamei Nano); polyethylene glycol monomethacrylate (Hongde Yuexin);

[0034] Unless otherwise specified, the following are parts by mass and mass ratios;

[0035] The preparation steps of epoxy silica are as follows: take 1 part of silane coupling agent KH560, add it to 50 parts of a mixed solution of ethanol and water (ethanol to water volume ratio of 1:1), stir evenly, heat to 60°C, add 10 parts of silica, keep warm and stir for 6 hours, filter and dry to obtain epoxy silica;

[0036] Example 1: S1: 0.5 parts of polybenzimidazole were added to 30 parts of N,N-dimethylformamide, stirred uniformly under nitrogen protection, 0.1 parts of sodium hydride were added, and the mixture was stirred at room temperature for 24 hours. The mixture was cooled to 0°C, 0.06 parts of 1-bromo-4-chlorobutane were added, and the mixture was reacted for 15 hours. Excess ice water was added for precipitation, and the precipitate was washed and dried at room temperature for 24 hours to obtain chlorobutylated polybenzimidazole.

[0037] 0.6 parts of chlorobutylated polybenzimidazole was added to 20 parts of N-methylpyrrolidone, and the mixture was stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added, and the mixture was stirred for 1 hour. The mixture was stirred at 95°C for 30 hours, and excess water was added for precipitation. The precipitate was washed and dried at 55°C for 24 hours to obtain hydroxylated polybenzimidazole.

[0038] S2: Add 30 parts of methyltetrahydrophthalic anhydride, 3 parts of hydroxylated polybenzimidazole and 0.03 parts of 4-dimethylaminopyridine to 100 parts of dimethyl sulfoxide, stir and dissolve, heat at 65°C for 3 hours, cool, remove the solvent under reduced pressure, and dry to obtain a polybenzimidazole curing agent;

[0039] S3: Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran (the amount of tetrahydrofuran added is 5 times the mass of methyltetrahydrophthalic anhydride), add 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine added is 0.1 wt% of the methyltetrahydrophthalic anhydride), heat at 65°C for 3 h, remove the solvent, and obtain modified polyethylene glycol monomethacrylate;

[0040] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol were sequentially added to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of the modified polyethylene glycol monomethacrylate), and a photoinitiator (photoinitiator 1024, the amount of which was 0.5% of the mass of the modified polyethylene glycol monomethacrylate) was added. The mixture was subjected to UV light click reaction for 1 hour, washed, and dried to obtain a polyethylene glycol curing agent.

[0041] The molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:2; the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is 4:1;

[0042] S4: mixing polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of 3:3:6 to obtain a curing agent;

[0043] S5: Mix N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:4 to obtain a reactive diluent;

[0044] S6: 65 parts of bisphenol A epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silicon dioxide were mixed uniformly to obtain an epoxy resin material.

[0045] Example 2: S1: 0.5 parts of polybenzimidazole were added to 30 parts of N,N-dimethylformamide, stirred uniformly under nitrogen protection, 0.1 parts of sodium hydride were added, and the mixture was stirred at room temperature for 24 hours. The mixture was cooled to 0°C, 0.05 parts of 1-bromo-4-chlorobutane were added, and the mixture was reacted for 15 hours. Excess ice water was added for precipitation, and the precipitate was washed and dried at room temperature for 24 hours to obtain chlorobutylated polybenzimidazole.

[0046] 0.5 parts of chlorobutylated polybenzimidazole was added to 20 parts of N-methylpyrrolidone, and the mixture was stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added, and the mixture was stirred for 1 hour. The mixture was stirred at 95°C for 30 hours, and excess water was added for precipitation. The precipitate was washed and dried at 55°C for 24 hours to obtain hydroxylated polybenzimidazole.

[0047] S2: Add 20 parts of methyltetrahydrophthalic anhydride, 2 parts of hydroxylated polybenzimidazole and 0.03 parts of 4-dimethylaminopyridine to 100 parts of dimethyl sulfoxide, stir and dissolve, heat at 65°C for 3 hours, cool, remove the solvent under reduced pressure, and dry to obtain a polybenzimidazole curing agent;

[0048] S3: Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran (the amount of tetrahydrofuran added is 5 times the mass of methyltetrahydrophthalic anhydride), add 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine added is 0.1 wt% of the methyltetrahydrophthalic anhydride), heat at 65°C for 3 h, remove the solvent, and obtain modified polyethylene glycol monomethacrylate;

[0049] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol were sequentially added to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of the modified polyethylene glycol monomethacrylate), and a photoinitiator (photoinitiator 1024, the amount of which was 0.5% of the mass of the modified polyethylene glycol monomethacrylate) was added. The mixture was subjected to UV light click reaction for 1 hour, washed, and dried to obtain a polyethylene glycol curing agent.

[0050] The molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:2; the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is 4:1;

[0051] S4: mixing polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of 2:3:6 to obtain a curing agent;

[0052] S5: Mix N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:4 to obtain a reactive diluent;

[0053] S6: 70 parts of bisphenol A epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 15 parts of reactive diluent, and 10 parts of epoxy silicon dioxide were mixed uniformly to obtain an epoxy resin material.

[0054] Example 3: S1: 0.6 parts of polybenzimidazole were added to 30 parts of N,N-dimethylformamide, stirred uniformly under nitrogen protection, 0.15 parts of sodium hydride were added, and the mixture was stirred at room temperature for 24 hours. The mixture was cooled to 0°C, 0.06 parts of 1-bromo-4-chlorobutane were added, and the mixture was reacted for 15 hours. Excess ice water was added for precipitation, and the precipitate was washed and dried at room temperature for 24 hours to obtain chlorobutylated polybenzimidazole;

[0055] 0.6 parts of chlorobutylated polybenzimidazole was added to 20 parts of N-methylpyrrolidone, and the mixture was stirred evenly under nitrogen protection. 2 parts of N-methyl-2-hydroxyethylamine was added, and the mixture was stirred for 1 hour. The mixture was stirred at 95°C for 30 hours, and excess water was added for precipitation. The precipitate was washed and dried at 55°C for 24 hours to obtain hydroxylated polybenzimidazole.

[0056] S2: Add 30 parts of methyltetrahydrophthalic anhydride, 4 parts of hydroxylated polybenzimidazole and 0.03 parts of 4-dimethylaminopyridine to 100 parts of dimethyl sulfoxide, stir and dissolve, heat at 65°C for 3 hours, cool, remove the solvent under reduced pressure, and dry to obtain a polybenzimidazole curing agent;

[0057] S3: Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran (the amount of tetrahydrofuran added is 5 times the mass of methyltetrahydrophthalic anhydride), add 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine added is 0.1 wt% of the methyltetrahydrophthalic anhydride), heat at 65°C for 3 h, remove the solvent, and obtain modified polyethylene glycol monomethacrylate;

[0058] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol were sequentially added to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of the modified polyethylene glycol monomethacrylate), and a photoinitiator (photoinitiator 1024, the amount of which was 0.5% of the mass of the modified polyethylene glycol monomethacrylate) was added. The mixture was subjected to UV light click reaction for 1 hour, washed, and dried to obtain a polyethylene glycol curing agent.

[0059] The molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:2; the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is 4:1;

[0060] S4: mixing polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of 2:2:5 to obtain a curing agent;

[0061] S5: Mix N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:4 to obtain a reactive diluent;

[0062] S6: 65 parts of bisphenol A epoxy resin, 55 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silicon dioxide were mixed uniformly to obtain an epoxy resin material.

[0063] Comparative Example 1 (the addition ratio of the polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride was changed, and the remaining method steps were consistent with Example 1): S1: 0.5 parts of polybenzimidazole were added to 30 parts of N,N-dimethylformamide, and stirred evenly under nitrogen protection. 0.1 parts of sodium hydride were added, and the mixture was stirred at room temperature for 24 hours. The mixture was cooled to 0°C, and 0.06 parts of 1-bromo-4-chlorobutane were added. The mixture was reacted for 15 hours, and excess ice water was added for precipitation. The precipitate was washed and dried at room temperature for 24 hours to obtain chlorobutylated polybenzimidazole.

[0064] 0.6 parts of chlorobutylated polybenzimidazole was added to 20 parts of N-methylpyrrolidone, and the mixture was stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added, and the mixture was stirred for 1 hour. The mixture was stirred at 95°C for 30 hours, and excess water was added for precipitation. The precipitate was washed and dried at 55°C for 24 hours to obtain hydroxylated polybenzimidazole.

[0065] S2: Add 30 parts of methyltetrahydrophthalic anhydride, 3 parts of hydroxylated polybenzimidazole and 0.03 parts of 4-dimethylaminopyridine to 100 parts of dimethyl sulfoxide, stir and dissolve, heat at 65°C for 3 hours, cool, remove the solvent under reduced pressure, and dry to obtain a polybenzimidazole curing agent;

[0066] S3: Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran, add 4-dimethylaminopyridine, heat at 65°C for 3 hours, remove the solvent, and obtain modified polyethylene glycol monomethacrylate;

[0067] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol were sequentially added to tetrahydrofuran, a photoinitiator was added, and the mixture was subjected to UV light click reaction for 1 hour, followed by washing and drying to obtain a polyethylene glycol curing agent;

[0068] The molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:2; the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is 4:1;

[0069] S4: mixing polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of 1:4:7 to obtain a curing agent;

[0070] S5: Mix N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:4 to obtain a reactive diluent;

[0071] S6: 65 parts of bisphenol A epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silicon dioxide were mixed uniformly to obtain an epoxy resin material.

[0072] Comparative Example 2 (the addition ratio of the polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride was changed, and the remaining method steps were consistent with Example 1): S1: 0.5 parts of polybenzimidazole were added to 30 parts of N,N-dimethylformamide, and stirred evenly under nitrogen protection. 0.1 parts of sodium hydride were added, and the mixture was stirred at room temperature for 24 hours. The mixture was cooled to 0°C, and 0.06 parts of 1-bromo-4-chlorobutane were added. The mixture was reacted for 15 hours, and excess ice water was added for precipitation. The precipitate was washed and dried at room temperature for 24 hours to obtain chlorobutylated polybenzimidazole.

[0073] 0.6 parts of chlorobutylated polybenzimidazole was added to 20 parts of N-methylpyrrolidone, and the mixture was stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added, and the mixture was stirred for 1 hour. The mixture was stirred at 95°C for 30 hours, and excess water was added for precipitation. The precipitate was washed and dried at 55°C for 24 hours to obtain hydroxylated polybenzimidazole.

[0074] S2: Add 30 parts of methyltetrahydrophthalic anhydride, 3 parts of hydroxylated polybenzimidazole and 0.03 parts of 4-dimethylaminopyridine to 100 parts of dimethyl sulfoxide, stir and dissolve, heat at 65°C for 3 hours, cool, remove the solvent under reduced pressure, and dry to obtain a polybenzimidazole curing agent;

[0075] S3: Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran, add 4-dimethylaminopyridine, heat at 65°C for 3 hours, remove the solvent, and obtain modified polyethylene glycol monomethacrylate;

[0076] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol were sequentially added to tetrahydrofuran, a photoinitiator was added, and the mixture was subjected to UV light click reaction for 1 hour, followed by washing and drying to obtain a polyethylene glycol curing agent;

[0077] The molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:2; the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is 4:1;

[0078] S4: mixing polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of 4:3:5 to obtain a curing agent;

[0079] S5: Mix N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:4 to obtain a reactive diluent;

[0080] S6: 65 parts of bisphenol A epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silicon dioxide were mixed uniformly to obtain an epoxy resin material.

[0081] Comparative Example 3 (the addition ratio of N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether was changed, and the remaining method steps were consistent with Example 1): S1: 0.5 parts of polybenzimidazole were added to 30 parts of N,N-dimethylformamide, and stirred evenly under nitrogen protection. 0.1 parts of sodium hydride were added, and the mixture was stirred at room temperature for 24 hours. The mixture was cooled to 0°C, 0.06 parts of 1-bromo-4-chlorobutane were added, and the reaction was carried out for 15 hours. Excess ice water was added for precipitation, and the precipitate was washed and dried at room temperature for 24 hours to obtain chlorobutylated polybenzimidazole.

[0082] 0.6 parts of chlorobutylated polybenzimidazole was added to 20 parts of N-methylpyrrolidone, and the mixture was stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added, and the mixture was stirred for 1 hour. The mixture was stirred at 95°C for 30 hours, and excess water was added for precipitation. The precipitate was washed and dried at 55°C for 24 hours to obtain hydroxylated polybenzimidazole.

[0083] S2: Add 30 parts of methyltetrahydrophthalic anhydride, 3 parts of hydroxylated polybenzimidazole and 0.03 parts of 4-dimethylaminopyridine to 100 parts of dimethyl sulfoxide, stir and dissolve, heat at 65°C for 3 hours, cool, remove the solvent under reduced pressure, and dry to obtain a polybenzimidazole curing agent;

[0084] S3: Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran, add 4-dimethylaminopyridine, heat at 65°C for 3 hours, remove the solvent, and obtain modified polyethylene glycol monomethacrylate;

[0085] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol were sequentially added to tetrahydrofuran, a photoinitiator was added, and the mixture was subjected to UV light click reaction for 1 hour, followed by washing and drying to obtain a polyethylene glycol curing agent;

[0086] The molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:2; the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is 4:1;

[0087] S4: mixing polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of 3:3:6 to obtain a curing agent;

[0088] S5: Mix N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:3 to obtain a reactive diluent;

[0089] S6: 65 parts of bisphenol A epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silicon dioxide were mixed uniformly to obtain an epoxy resin material.

[0090] Comparative Example 4 (the curing agent preparation method was changed, and the remaining steps were the same as those in Example 1): S1: 30 parts of methyltetrahydrophthalic anhydride and 3 parts of polybenzimidazole were mixed to obtain a mixture A;

[0091] S2: polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride are mixed in a molar ratio of 1:2 to obtain a mixture B;

[0092] S3: Mix 30 parts of methyltetrahydrophthalic anhydride and 3 parts of mixture B to obtain mixture C;

[0093] S4: Mix mixture A, mixture C, and methyltetrahydrophthalic anhydride in a mass ratio of 3:3:6 to obtain a curing agent;

[0094] S5: Mix N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:4 to obtain a reactive diluent;

[0095] S6: 65 parts of bisphenol A epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silicon dioxide were mixed uniformly to obtain an epoxy resin material.

[0096] Performance test: Vacuum-dried insulating paper (cellulose crepe paper, with a fiber diameter of approximately 300 μm) was impregnated with the epoxy resin materials prepared in Examples 1-3 and Comparative Examples 1-4 under vacuum at 50°C for 12 h. The paper was then heated and cured for vacuum degassing. The paper was then cured at 80°C for 0.5 h, 120°C for 2 h, and 150°C for 2 h. The sample was dried to obtain a 0.5 mm sample and its electrical properties were tested. The tensile strength was tested using a universal testing machine HZ1003 at a tensile rate of 2 mm / min. See Table 1 for details.

[0097] Table 1:

[0098] Conclusion: From Table 1, changing the addition ratio of polybenzimidazole curing agent, polyethylene glycol curing agent, and phthalic anhydride will lead to significant changes in performance, and the increase in viscosity will lead to unstable electrical strength, affecting use; changing the addition ratio of N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether will also lead to significant changes in performance, which is due to changes in cross-linking degree, so the addition ratio needs to be strictly controlled; Comparative Example 4 simply mixes the raw materials to obtain the curing agent, and the performance is significantly reduced after addition, which is due to the influence of compatibility. This shows the significance of prior modification; In summary, the epoxy resin material prepared by this scheme has the advantages of high strength and low viscosity, good electrical properties, and can be used for high-voltage catheters.

[0099] Performance test 2: Referring to GB / T19466.2, the Tg of Examples 1 to 3 were all greater than or equal to 130°C, proving that they have good stability in high temperature environments.

[0100] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An epoxy resin material for high-pressure conduits, characterized by: Including the following raw materials, calculated by mass: 65-70 parts of epoxy resin; 55-60 parts of curing agent; Imidazole accelerator 0.1~0.2 parts; 10-15 parts of active diluent; 8-15 parts of epoxy silica; The diluent includes N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:(4-5).

2. The epoxy resin material for high-pressure conduits according to claim 1, characterized in that: The curing agent includes a polybenzimidazole curing agent, a polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of (2-3): (2-3): (5-6).

3. The epoxy resin material for high-pressure conduits according to claim 2, characterized in that: The preparation of the polybenzimidazole curing agent comprises the following steps: adding methyltetrahydrophthalic anhydride and hydroxylated polybenzimidazole to dimethyl sulfoxide, adding 4-dimethylaminopyridine, reacting at 60-65° C. for 2-3 hours, and removing the solvent to obtain the polybenzimidazole curing agent.

4. The epoxy resin material for high-pressure conduits according to claim 3, characterized in that: The polybenzimidazole curing agent comprises the following raw materials, calculated by mass: 20-30 parts of methyltetrahydrophthalic anhydride, 2-4 parts of hydroxylated polybenzimidazole, and 0.01-0.05 parts of 4-dimethylaminopyridine.

5. The epoxy resin material for high-pressure conduits according to claim 3, characterized in that: The preparation of the hydroxylated polybenzimidazole comprises the following steps: Add polybenzimidazole to N,N-dimethylformamide, stir evenly under nitrogen protection, add sodium hydride, stir at room temperature for 20-24 hours, add 1-bromo-4-chlorobutane under ice bath, stir for 12-15 hours, precipitate, wash, and dry to obtain chlorobutylated polybenzimidazole; Add chlorobutylated polybenzimidazole to N-methylpyrrolidone, stir evenly under nitrogen protection, add N-methyl-2-hydroxyethylamine, stir at room temperature for 0.5-1 hour, heat to 80-100°C and stir for 20-30 hours, add excess water for precipitation, wash the precipitate, and dry to obtain hydroxylated polybenzimidazole.

6. The epoxy resin material for high-pressure conduits according to claim 5, characterized in that: The chlorobutylated polybenzimidazole comprises the following raw materials, calculated by mass: 0.5-0.6 parts of polybenzimidazole, 20-30 parts of N,N-dimethylformamide, 0.1-0.15 parts of sodium hydride, and 0.05-0.06 parts of 1-bromo-4-chlorobutane; The hydroxylated polybenzimidazole comprises the following raw materials, calculated by weight: 0.5-0.6 parts of chlorobutylated polybenzimidazole, 10-20 parts of N-methylpyrrolidone, and 1-2 parts of N-methyl-2-hydroxyethylamine.

7. The epoxy resin material for high-pressure conduits according to claim 2, characterized in that: The preparation of the polyethylene glycol curing agent comprises the following steps: Add polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride to tetrahydrofuran, add 4-dimethylaminopyridine, heat at 60-65°C for 2-3 hours, remove the solvent, and obtain modified polyethylene glycol monomethacrylate; Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)thiophenol are sequentially added to tetrahydrofuran, a photoinitiator is added, ultraviolet light click reaction is performed for 1 to 2 hours, and the mixture is washed and dried to obtain a polyethylene glycol curing agent.

8. The epoxy resin material for high-pressure conduits according to claim 7, characterized in that: The molar ratio of the polyethylene glycol monomethacrylate to methyltetrahydrophthalic anhydride is 1:(1.5-2.5); the mass ratio of the modified polyethylene glycol monomethacrylate to 3-(trifluoromethyl)thiophenol is (4-4.5):

1.

9. The epoxy resin material for high-pressure conduits according to claim 1, characterized in that: The curing process of the epoxy resin material is: curing at 60-80° C. for 0.5-1 hour, curing at 100-120° C. for 1-2 hours, and curing at 130-150° C. for 1-2 hours.

10. The method for preparing an epoxy resin material for a high-pressure pipe according to any one of claims 1 to 9, characterized in that: The following steps are involved: Take bisphenol A epoxy resin, curing agent, imidazole accelerator, active diluent and epoxy silicon dioxide, stir evenly to obtain epoxy resin material.

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