An epoxy resin material for high-pressure conduits and its preparation method

Abstract

This invention relates to the field of polymer compound technology and discloses an epoxy resin material for high-pressure conduits and its preparation method. The preparation method comprises the following raw materials, by mass parts: 65-70 parts of bisphenol A type epoxy resin; 55-60 parts of curing agent; 0.1-0.2 parts of imidazole accelerator; 10-15 parts of reactive diluent; and 8-15 parts of epoxy-based silica. The diluent is N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:(4-5); the curing agent is polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of (2-3):(2-3):(5-6). The epoxy resin material prepared by this application has excellent electrical and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of polymer compound technology, and discloses an epoxy resin material for high-pressure conduits and its preparation method. Background Technology

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

[0003] In summary, solving the above problems and developing a high-thermal-stability, high-strength, low-viscosity epoxy resin material for high-pressure conduits and its preparation method is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide an epoxy resin material for high-pressure conduits and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an epoxy resin material for high-pressure conduits, comprising the following raw materials, in parts by mass:

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

[0007] 55-60 parts of curing agent;

[0008] Imidazole accelerator 0.1~0.2 parts;

[0009] 10-15 parts of reactive diluent;

[0010] 8-15 parts of epoxy-based silica;

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

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

[0013] In a more optimized manner, 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℃ for 2~3h, cooling, removing solvent under reduced pressure, and drying to obtain the polybenzimidazole curing agent.

[0014] In a more optimized manner, the polybenzimidazole curing agent comprises the following raw materials, in parts by mass: 20-30 parts methyltetrahydrophthalic anhydride, 2-4 parts hydroxylated polybenzimidazole, and 0.01-0.05 parts 4-dimethylaminopyridine.

[0015] In a more optimized manner, the preparation of the hydroxylated polybenzimidazole includes the following steps: adding polybenzimidazole to N,N-dimethylformamide, stirring evenly under nitrogen protection, adding sodium hydride, stirring at room temperature for 20-24 h, cooling to 0°C, adding 1-bromo-4-chlorobutane, stirring for 12-15 h, adding excess ice water to precipitate, taking the precipitate, washing, and drying to obtain chlorobutylated polybenzimidazole;

[0016] Chloroprene-modified polybenzimidazole was added to N-methylpyrrolidone and stirred until homogeneous under nitrogen protection. N-methyl-2-hydroxyethylamine was then added and stirred at room temperature for 0.5-1 h. The mixture was then heated to 80-100℃ and stirred for 20-30 h. Excess water was added to precipitate the mixture. The precipitate was washed and dried to obtain hydroxylated polybenzimidazole.

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

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

[0019] In a more optimized manner, the preparation of the polyethylene glycol curing agent includes the following steps:

[0020] Polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride were added to tetrahydrofuran (the amount of tetrahydrofuran added was 5 to 8 times the mass of methyltetrahydrophthalic anhydride), and 4-dimethylaminopyridine was added (the amount of 4-dimethylaminopyridine added was 0.1 to 0.3 wt% of methyltetrahydrophthalic anhydride). The mixture was heated at 60 to 65 °C for 2 to 3 hours to remove the solvent, thereby obtaining modified polyethylene glycol monomethacrylate.

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

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

[0023] A more optimized method for preparing the above-mentioned epoxy resin material for high-pressure conduits is as follows: take bisphenol A type epoxy resin, curing agent, imidazole accelerator, and reactive diluent, stir evenly, and obtain epoxy resin material.

[0024] In a more optimized manner, the epoxy resin material curing process is as follows: vacuum degassing, curing at 60~80℃ for 0.5~1 hours, curing at 100~120℃ for 1~2 hours, and curing at 130~150℃ for 1~2 hours.

[0025] A more optimized preparation method for epoxy-based silica is as follows: Take silane coupling agent KH560, add it to a mixed solution of ethanol and water (volume ratio of ethanol to water 1:1), stir evenly, heat to 60~70℃, add silica, keep warm and stir for 4~6h, filter and dry to obtain epoxy-based silica; the mass ratio of silane coupling agent KH560 to silica is (0.5~1):10; this inorganic filler has good compatibility, can relieve thermal stress, reduce the coefficient of linear expansion, 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 this application has good wettability to paper substrate, effectively ensuring electrical and mechanical properties.

[0027] In this solution, by limiting the components and content of the diluent, including the compounding of high molecular weight N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and low molecular weight ethylene glycol diglycidyl ether, the viscosity of the epoxy material is effectively reduced, its wettability to the paper substrate is improved, partial discharge is reduced, and electrical properties are enhanced. Specifically, N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane provides crosslinking density, promoting the formation of a three-dimensional network structure and enhancing the integrity of the crosslinking network while diluting it; while ethylene glycol diglycidyl ether effectively balances viscosity and promotes improved wettability; simultaneously, the flexible chain segments effectively toughen the epoxy resin, suppressing its brittleness and improving stress concentration. Thus, the combination of these two components, while reducing viscosity, compensates for the performance shortcomings of traditional diluents through their multifunctional groups and rigid-flexible synergistic structure, achieving high wettability, high crosslinking degree, and improved 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 this scheme, acid anhydride is used as the main curing agent, and polybenzimidazole curing agent and polyethylene glycol curing agent are combined to effectively form a uniform curing network, improve the toughness and interfacial bonding of the material, further improve the crack resistance, and promote the improvement of the mechanical and electrical properties of epoxy resin materials.

[0029] Anhydride curing agents can effectively ensure high Tg, low shrinkage, and excellent electrical insulation, but they do not solve the problem of excessive brittleness, which easily leads to microcracks. Furthermore, anhydride curing requires accelerators to improve curing energy. Therefore, polyethylene glycol curing agents are introduced, utilizing their flexible chain segments as elastic microregions to effectively suppress microcrack formation. Polybenzimidazole is used to further improve the curing performance of anhydrides. A gradient curing process is achieved using these three agents, effectively ensuring the uniformity of the cross-linked network and suppressing curing stress and microcracks.

[0030] Meanwhile, the properties of polybenzimidazole itself contribute to improved electrical performance and can form π-π stacking with paper-based fibers, enhancing interfacial interactions; while the fluorine groups in the polyethylene glycol curing agent can further optimize electrical performance. It is important to note that the relevant proportions need to be limited. Excessive addition of benzimidazole curing agent will lead to reduced toughness and excessively high viscosity; excessive addition of polyethylene glycol curing agent will dilute the crosslinking point density due to the long-chain structure, resulting in a loose cured network and decreased performance.

[0031] In summary, this solution effectively achieves a uniform cross-linked network by limiting the curing agent, improving curing stress and microcrack defects, significantly reducing the risk of partial discharge, and improving crack resistance; thereby improving electrical and mechanical properties and ensuring applicability. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that there are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary examples include: bisphenol A type epoxy resin (base resin EPON828); imidazole accelerator (1-methylimidazolium); polybenzimidazole (Celazole PBI U-60); N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane (CAS: 28768-32-3); silica (N-03, Yamei Nano); polyethylene glycol monomethacrylate (Hongde Yuexin).

[0034] Unless otherwise specified, all figures below are parts by weight or 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 (volume ratio of ethanol to water 1:1), stir evenly, heat to 60℃, 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 and stirred evenly under nitrogen protection. 0.1 parts of sodium hydride were added and stirred at room temperature for 24 h. After cooling to 0°C, 0.06 parts of 1-bromo-4-chlorobutane were added and reacted for 15 h. Excess ice water was added to precipitate the product. The precipitate was washed and dried at room temperature for 24 h to obtain chlorobutylated polybenzimidazole.

[0037] 0.6 parts of chlorobutylated polybenzimidazole were added to 20 parts of N-methylpyrrolidone and stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added and stirred continuously for 1 hour. The mixture was stirred at 95°C for 30 hours. Excess water was added to precipitate the precipitate. 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 to dissolve, heat at 65°C for 3 hours, cool, remove solvent under reduced pressure and dry to obtain polybenzimidazole curing agent;

[0039] S3: Polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride were added to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of methyltetrahydrophthalic anhydride), and 4-dimethylaminopyridine was added (the amount of 4-dimethylaminopyridine added was 0.1wt% of methyltetrahydrophthalic anhydride). The mixture was heated at 65°C for 3 hours to remove the solvent, and the modified polyethylene glycol monomethacrylate was obtained.

[0040] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)benzylthiophenol were added sequentially to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of modified polyethylene glycol monomethacrylate), and a photoinitiator (photoinitiator 1024, the amount added was 0.5% of the mass of modified polyethylene glycol monomethacrylate) was added. The reaction was carried out under ultraviolet light for 1 hour, and the product was washed and dried to obtain polyethylene glycol curing agent.

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

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

[0043] S5: Mix N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether at a mass ratio of 1:4 to obtain an active diluent;

[0044] S6: Mix 65 parts of bisphenol A type epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silica evenly to obtain epoxy resin material.

[0045] Example 2: 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 stirred at room temperature for 24 h. After cooling to 0°C, 0.05 parts of 1-bromo-4-chlorobutane were added and reacted for 15 h. Excess ice water was added to precipitate the product. The precipitate was washed and dried at room temperature for 24 h to obtain chlorobutylated polybenzimidazole.

[0046] 0.5 parts of chlorobutylated polybenzimidazole were added to 20 parts of N-methylpyrrolidone and stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added and stirred continuously for 1 hour. The mixture was stirred at 95°C for 30 hours. Excess water was added to precipitate the precipitate. 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 to dissolve, heat at 65°C for 3 hours, cool, remove solvent under reduced pressure and dry to obtain polybenzimidazole curing agent;

[0048] S3: Polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride were added to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of methyltetrahydrophthalic anhydride), and 4-dimethylaminopyridine was added (the amount of 4-dimethylaminopyridine added was 0.1wt% of methyltetrahydrophthalic anhydride). The mixture was heated at 65°C for 3 hours to remove the solvent, and the modified polyethylene glycol monomethacrylate was obtained.

[0049] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)benzylthiophenol were added sequentially to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of modified polyethylene glycol monomethacrylate), and a photoinitiator (photoinitiator 1024, the amount added was 0.5% of the mass of modified polyethylene glycol monomethacrylate) was added. The reaction was carried out under ultraviolet light for 1 hour, and the product was washed and dried to obtain polyethylene glycol curing agent.

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

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

[0052] S5: Mix N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether at a mass ratio of 1:4 to obtain an active diluent;

[0053] S6: Mix 70 parts of bisphenol A type epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 15 parts of reactive diluent, and 10 parts of epoxy silica evenly to obtain epoxy resin material.

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

[0055] 0.6 parts of chlorobutylated polybenzimidazole were added to 20 parts of N-methylpyrrolidone and stirred evenly under nitrogen protection. 2 parts of N-methyl-2-hydroxyethylamine were added and stirred continuously for 1 hour. The mixture was stirred at 95°C for 30 hours. Excess water was added to precipitate the mixture. 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 to dissolve, heat at 65°C for 3 hours, cool, remove solvent under reduced pressure and dry to obtain polybenzimidazole curing agent;

[0057] S3: Polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride were added to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of methyltetrahydrophthalic anhydride), and 4-dimethylaminopyridine was added (the amount of 4-dimethylaminopyridine added was 0.1wt% of methyltetrahydrophthalic anhydride). The mixture was heated at 65°C for 3 hours to remove the solvent, and the modified polyethylene glycol monomethacrylate was obtained.

[0058] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)benzylthiophenol were added sequentially to tetrahydrofuran (the amount of tetrahydrofuran added was 5 times the mass of modified polyethylene glycol monomethacrylate), and a photoinitiator (photoinitiator 1024, the amount added was 0.5% of the mass of modified polyethylene glycol monomethacrylate) was added. The reaction was carried out under ultraviolet light for 1 hour, and the product was washed and dried to obtain polyethylene glycol curing agent.

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

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

[0061] S5: Mix N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether at a mass ratio of 1:4 to obtain an active diluent;

[0062] S6: Mix 65 parts of bisphenol A type epoxy resin, 55 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silica evenly to obtain epoxy resin material.

[0063] Comparative Example 1 (the proportions of polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride were changed, and the remaining steps were the same as in 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 stirred at room temperature for 24 h. After cooling to 0°C, 0.06 parts of 1-bromo-4-chlorobutane were added and reacted for 15 h. Excess ice water was added to precipitate the product. The precipitate was washed and dried at room temperature for 24 h to obtain chlorobutylated polybenzimidazole.

[0064] 0.6 parts of chlorobutylated polybenzimidazole were added to 20 parts of N-methylpyrrolidone and stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added and stirred continuously for 1 hour. The mixture was stirred at 95°C for 30 hours. Excess water was added to precipitate the precipitate. 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 to dissolve, heat at 65°C for 3 hours, cool, remove solvent under reduced pressure and dry to obtain polybenzimidazole curing agent;

[0066] S3: Polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride were added to tetrahydrofuran, 4-dimethylaminopyridine was added, and the mixture was heated at 65°C for 3 hours to remove the solvent, thereby obtaining modified polyethylene glycol monomethacrylate.

[0067] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)benzylthiophenol were added sequentially to tetrahydrofuran, a photoinitiator was added, and the reaction was carried out under ultraviolet light for 1 hour. After washing and drying, polyethylene glycol curing agent was obtained.

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

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

[0070] S5: Mix N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether at a mass ratio of 1:4 to obtain an active diluent;

[0071] S6: Mix 65 parts of bisphenol A type epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silica evenly to obtain epoxy resin material.

[0072] Comparative Example 2 (the proportions of polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride were changed, and the remaining steps were the same as in 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 stirred at room temperature for 24 h. After cooling to 0°C, 0.06 parts of 1-bromo-4-chlorobutane were added and reacted for 15 h. Excess ice water was added to precipitate the product. The precipitate was washed and dried at room temperature for 24 h to obtain chlorobutylated polybenzimidazole.

[0073] 0.6 parts of chlorobutylated polybenzimidazole were added to 20 parts of N-methylpyrrolidone and stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added and stirred continuously for 1 hour. The mixture was stirred at 95°C for 30 hours. Excess water was added to precipitate the precipitate. 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 to dissolve, heat at 65°C for 3 hours, cool, remove solvent under reduced pressure and dry to obtain polybenzimidazole curing agent;

[0075] S3: Polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride were added to tetrahydrofuran, 4-dimethylaminopyridine was added, and the mixture was heated at 65°C for 3 hours to remove the solvent, thereby obtaining modified polyethylene glycol monomethacrylate.

[0076] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)benzylthiophenol were added sequentially to tetrahydrofuran, a photoinitiator was added, and the reaction was carried out under ultraviolet light for 1 hour. After washing and drying, polyethylene glycol curing agent was obtained.

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

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

[0079] S5: Mix N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether at a mass ratio of 1:4 to obtain an active diluent;

[0080] S6: Mix 65 parts of bisphenol A type epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silica evenly to obtain epoxy resin material.

[0081] Comparative Example 3 (the addition ratio of N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether was changed, and the remaining steps were the same as in Example 1): S1: 0.5 parts of polybenzimidazole were added to 30 parts of N,N-dimethylformamide, stirred evenly under nitrogen protection, 0.1 parts of sodium hydride were added, stirred at room temperature for 24 h, cooled to 0 °C, 0.06 parts of 1-bromo-4-chlorobutane were added, reacted for 15 h, excess ice water was added to precipitate, the precipitate was washed, and dried at room temperature for 24 h to obtain chlorobutylated polybenzimidazole;

[0082] 0.6 parts of chlorobutylated polybenzimidazole were added to 20 parts of N-methylpyrrolidone and stirred evenly under nitrogen protection. 1 part of N-methyl-2-hydroxyethylamine was added and stirred continuously for 1 hour. The mixture was stirred at 95°C for 30 hours. Excess water was added to precipitate the precipitate. 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 to dissolve, heat at 65°C for 3 hours, cool, remove solvent under reduced pressure and dry to obtain polybenzimidazole curing agent;

[0084] S3: Polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride were added to tetrahydrofuran, 4-dimethylaminopyridine was added, and the mixture was heated at 65°C for 3 hours to remove the solvent, thereby obtaining modified polyethylene glycol monomethacrylate.

[0085] Modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)benzylthiophenol were added sequentially to tetrahydrofuran, a photoinitiator was added, and the reaction was carried out under ultraviolet light for 1 hour. After washing and drying, polyethylene glycol curing agent was obtained.

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

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

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

[0089] S6: Mix 65 parts of bisphenol A type epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silica evenly to obtain epoxy resin material.

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

[0091] S2: Mix polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride in a molar ratio of 1:2 to obtain 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'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether at a mass ratio of 1:4 to obtain an active diluent;

[0095] S6: Mix 65 parts of bisphenol A type epoxy resin, 60 parts of curing agent, 0.1 parts of 1-methylimidazole, 12 parts of reactive diluent, and 10 parts of epoxy silica evenly to obtain epoxy resin material.

[0096] Performance testing: Vacuum-dried insulating paper (cellulose crepe paper, fiber diameter approximately 300 μm) was taken, and epoxy resin materials prepared in Examples 1-3 and Comparative Examples 1-4 were used. The insulating paper was impregnated under vacuum at 50°C for 12 hours, then heated for curing and vacuum degassing, cured at 80°C for 0.5 hours, at 120°C for 2 hours, and at 150°C for 2 hours. After drying, 0.5 mm samples were obtained, and their electrical properties were tested. 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: Table 1 shows that changing the proportions of polybenzimidazole curing agent, polyethylene glycol curing agent, and phthalic anhydride leads to significant performance changes. Increased viscosity results in unstable electrical strength, affecting usability. Changing the proportions of N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether also leads to significant performance changes due to changes in crosslinking degree; therefore, the proportions must be strictly controlled. In Comparative Example 4, the curing agent obtained by simply mixing the raw materials resulted in a significant performance decrease after addition, due to compatibility issues, highlighting the importance of pre-modification. In summary, the epoxy resin material prepared by this method has the advantages of high strength, low viscosity, and good electrical properties, making it suitable for high-pressure conduits.

[0099] Performance Test 2: Referring to GB / T19466.2, the Tg of Examples 1 to 3 were all greater than or equal to 130℃, 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An epoxy resin material for high-pressure conduits, characterized in that: Includes the following raw materials, by mass parts: 65-70 parts epoxy resin; 55-60 parts of curing agent; Imidazole accelerator 0.1~0.2 parts; 10-15 parts of reactive diluent; 8-15 parts of epoxy-based silica; The diluent comprises N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane and ethylene glycol diglycidyl ether in a mass ratio of 1:(4~5). The curing agent comprises polybenzimidazole curing agent, polyethylene glycol curing agent, and methyltetrahydrophthalic anhydride in a mass ratio of (2~3):(2~3):(5~6); The preparation of the polybenzimidazole curing agent includes the following steps: adding methyltetrahydrophthalic anhydride and hydroxylated polybenzimidazole to dimethyl sulfoxide, adding 4-dimethylaminopyridine, reacting at 60~65℃ for 2~3h, removing the solvent, and obtaining the polybenzimidazole curing agent; The preparation of the hydroxylated polybenzimidazole includes the following steps: adding polybenzimidazole to N,N-dimethylformamide, stirring evenly under nitrogen protection, adding sodium hydride, stirring at room temperature for 20-24 h, adding 1-bromo-4-chlorobutane under ice bath, stirring for 12-15 h, precipitating, washing, and drying to obtain chlorobutylated polybenzimidazole; adding chlorobutylated polybenzimidazole to N-methylpyrrolidone, stirring evenly under nitrogen protection, adding N-methyl-2-hydroxyethylamine, stirring at room temperature for 0.5-1 h, heating to 80-100℃ and stirring for 20-30 h, adding excess water to precipitate, taking the precipitate, washing, and drying to obtain hydroxylated polybenzimidazole; The preparation of the polyethylene glycol curing agent includes the following steps: polyethylene glycol monomethacrylate and methyltetrahydrophthalic anhydride are added to tetrahydrofuran, 4-dimethylaminopyridine is added, and the mixture is heated at 60-65°C for 2-3 hours to remove the solvent, thereby obtaining modified polyethylene glycol monomethacrylate; modified polyethylene glycol monomethacrylate and 3-(trifluoromethyl)benzylthiophenol are added sequentially to tetrahydrofuran, a photoinitiator is added, and the mixture is subjected to ultraviolet light click reaction for 1-2 hours, followed by washing and drying to obtain the polyethylene glycol curing agent.

2. The epoxy resin material for high-pressure conduits according to claim 1, characterized in that: The polybenzimidazole curing agent comprises the following raw materials, in parts by weight: 20-30 parts methyltetrahydrophthalic anhydride, 2-4 parts hydroxylated polybenzimidazole, and 0.01-0.05 parts 4-dimethylaminopyridine.

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

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

1.

5. The epoxy resin material for high-pressure conduits according to claim 1, characterized in that: The curing process of the epoxy resin material is as follows: curing at 60~80℃ for 0.5~1 hours, curing at 100~120℃ for 1~2 hours, and curing at 130~150℃ for 1~2 hours.

6. A method for preparing an epoxy resin material for high-pressure conduits according to any one of claims 1 to 5, characterized in that: The following steps are involved: Take bisphenol A type epoxy resin, curing agent, imidazole accelerator, reactive diluent, and epoxy silica, and stir evenly to obtain epoxy resin material.

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