Epoxy resin containing imide unit and preparation method thereof

Abstract

In response to the current problems that epoxy resins are brittle after curing and easily cause the heat resistance of the resin cured product to decrease or induce phase separation after toughening, the present invention provides a method for preparing a new epoxy resin containing imide units, aiming to achieve good compatibility between imide and epoxy resin at the molecular level, and utilizing the chemical advantages of high rigidity, high strength, and high heat resistance of the imide unit to solve the scientific problems of epoxy resin being brittle after curing and the easy decline in thermal performance caused by toughening from the source of the problem. The invention uses commercial dibasic acid anhydride as the basic monomer unit, and prepares a bisimide diphenol compound by combining it with a variety of active monomers, and then reacts it with epoxy halopropane to obtain a new epoxy resin containing imide units. The new epoxy resin developed by the present invention has good solubility, outstanding heat resistance, excellent processability, good impact toughness after curing, can meet the requirements of advanced resin-based composite materials, and is expected to further promote and deepen the application of epoxy resin in high-precision and cutting-edge technology fields such as aerospace.

Description

Technical Field

[0001] The present invention belongs to the field of synthesis of high-performance resins, and in particular relates to an epoxy resin whose main molecular chain contains imide units and has both high impact resistance and high heat resistance, and a preparation method thereof. Background Art

[0002] Epoxy (EP) resins are widely recognized as the most widely used and strategically important thermoset material due to their high mechanical strength, excellent chemical resistance, high heat resistance, outstanding electrical insulation, and strong adhesion. They are currently used as a matrix resin in anti-corrosion coatings, adhesives, semiconductor packaging materials, electrical insulation materials, and high-performance composites. Due to their unique chemical structure, EP resins play a vital role in industries such as transportation, construction, electronics, insulation, and aerospace. In 2019, China consumed over 1.6 million tons of EP resin, accounting for approximately 51.0% of global EP resin consumption. Western Europe, the United States, and South Korea accounted for 10.3%, 8.2%, and 5.7% of global EP resin consumption, respectively. EP resins have undoubtedly become an indispensable foundational material across various industrial sectors.

[0003] However, cured EP resins, similar to traditional thermosetting resins, exhibit a highly cross-linked molecular backbone, low plastic deformation, and significant brittleness. Furthermore, the volumetric shrinkage of the resin after curing generates internal stresses in the material, resulting in poor resistance to crack initiation and crack propagation, hindering its further application in high-performance composites. Currently, to address the prominent brittleness and poor crack propagation resistance of cured EP resins, scholars at home and abroad have conducted extensive toughening research. Key strategies include toughening with rubber (Res), thermoplastic polymers (TPs), liquid crystal polymers (LCPs), block copolymers (BCPs), nanomaterials (NMs), hyperbranched polymers (HBPs), bio-based materials (BBMs), and topological structures (TSs). The corresponding toughening mechanisms primarily involve stress dissipation through the construction of interpenetrating polymer networks (IPNs) or semi-penetrating polymer networks (SIPNs).

[0004] Compared with EP resin, polyimide (PI) is a special engineering plastic with excellent comprehensive performance. It has higher heat resistance, outstanding impact toughness, excellent mechanical strength, good dielectric properties, etc. Therefore, it is widely used as a high-performance resin matrix in high-tech fields such as aerospace, electronic packaging, weapons and equipment, and microelectronics. Since the 1990s, domestic and foreign scholars have tried to use PI to toughen and modify the cured EP resin, and have made certain progress. Sue et al. from Texas A&M University in the United States used polyetherimide (PEI) with a molecular weight of 10 kg / mol to compound with EP resin, and increased the critical stress intensity factor (K) of EP resin.IC ) from 0.70MPa·m before toughening 1 / 2 Increased to 1.67MPa·m 1 / 2 , and the modification effect is significant [Sue, H.-J.; et al. Polymer, 2023, 270, 125763.]. Unfortunately, due to the higher molecular weight and greater chain polarity of the PEI used compared to EP resin, the PEI toughening phase and the EP resin phase undergo obvious phase separation during the curing process, and a "double glass transition" behavior occurs [Sue, H.-J.; et al. Polymer, 2023, 270, 125763.]. This shows that using PI to toughen EP resin is feasible, but the inevitable phase separation causes the EP resin to form a phase structure of "phase inversion" and "co-continuous" models after curing, which destroys the homogeneity of the resin, resulting in a decrease in its long-term performance, creep resistance, and solvent resistance. To avoid phase separation, Qiu Zhiming et al. [Qiu, Z.; et al. J. Mater. Sci. 2016, 51, 10833.] from South China University of Technology directly compounded amino-terminated polyamic acid (PAA, average degree of polymerization n=1) with EP resin. By utilizing the ring-opening reaction of the active amino groups in the PAA molecular chain with the epoxy groups, they constructed an interpenetrating network structure between PI and EP, improving the compatibility between the PI and EP phases and the fracture toughness of the EP resin after curing. However, although the amino-terminated PAA has a theoretical degree of polymerization of 1, its composition is actually a mixture with a wide molecular weight distribution index. As a result, the final cured resin does not achieve complete compatibility between PI and EP resin at the molecular level. Furthermore, because the bonding strength of PI is lower than that of epoxy, the resulting cured resin exhibits poor tensile shear strength and thermal oxidative stability. Inspired by the research of Qiu Zhiming and others, the inventors envisioned whether it would be possible to address the problem at its source and directly introduce imide units into the molecular backbone of EP resins. This would mean developing an epoxy resin whose molecular backbone contains imide units, thereby achieving hybridization and complete compatibility between the PI phase and the EP resin phase at the molecular scale. This would not only improve the impact toughness and thermal properties of the cured EP resin, but also fully utilize the inherent advantages of the imide units, such as high strength, high rigidity, and high polarity, to give the EP resin better comprehensive physical properties, thereby expanding the product types and application range of EP resins.

[0005] It should be noted that a large number of literature surveys have found that, to date, there has been no report on the synthesis method of EP resins containing imide units on the main chain of the molecule.

[0006] Currently, EP resin is very brittle after curing, and toughening easily causes the heat resistance of the resin cured product to decrease or induces phase separation, which limits the application of EP resin in some high-heat-resistant fields. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of existing epoxy resins and prepare a new epoxy resin whose molecular main chain contains imide units. By utilizing the inherent advantages of imide units such as high rigidity, strong polarity, high strength, and high heat resistance, the impact toughness and comprehensive physical properties of EP resin after curing are improved.

[0008] The present invention provides a novel epoxy resin containing an imide unit, wherein the molecular structure of the epoxy resin is represented by the following general formula (I):

[0009]

[0010] Wherein, the molar ratio of the dibasic acid anhydride part, the compound E part and the epihalogenated propane part in formula (I) is 1:2:2; R1 represents O or S;

[0011] R2 represents a residue in compound E, R2 is a substituted or unsubstituted phenylene group, or a structural fragment represented by formula (II):

[0012]

[0013] R* in formula (II) is a residue of a diphenol compound, and R* is connected to R1 in formula (I); the benzene ring is connected to the N atom; M1 is O or S, and Y is H, -CF3 or -CH3;

[0014] R3 represents a residue in a dibasic acid anhydride.

[0015] The novel epoxy resin containing an imide unit, wherein the dibasic acid anhydride portion corresponds to any one or a combination of the following acid anhydrides, has the following chemical structure:

[0016]

[0017] The novel epoxy resin containing imide units, the epihalohydrin is any one of epifluorohydrin, epichlorohydrin, epibromohydrin, and epiiodohydrin, or a combination thereof.

[0018] The novel epoxy resin containing imide units, wherein the aminophenols contained in the compound corresponding to the compound E are: p-aminophenol, o-aminophenol, m-aminophenol, 2-methyl-4-aminophenol, tetramethyl-p-aminophenol, 3-methyl-4-aminophenol, 2-methyl-3-aminophenol, 3-methyl-2-aminophenol, 4-amino-3-trifluoromethylphenol, 4-amino-2-trifluoromethylphenol, 3-amino-2-trifluoromethylphenol, 2-phenyl-4-aminophenol, 3-isopropyl-4-aminophenol, 2-phenyl-3-aminophenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-3-trifluoromethylphenol, 2-phenyl-3-aminophenol, 3-isopropyl ...4-amino-3-trifluoromethylphenol, 2-phenyl-3-aminophenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-3-trifluoromethylphenol, 4-amino-2-trifluoromethylphenol, 3-isopropyl-2-trifluoromethylphenol, 2-phenyl-4-aminophenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-3-trifluoromethylphenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-2-trifluoromethylphenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-2-trifluoromethylphenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-2-trifluoromethylphenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-2-trifluoromethylphenol, 3-isopropyl-2-trifluoromethylphenol, 4-amino-2-trifluoro any one or a combination thereof of 4-amino-3-trifluoromethylthiophenol, 4-amino-2-trifluoromethylthiophenol, 3-phenyl-2-aminophenol, 2-amino-3-trifluoromethylphenol, p-aminothiophenol, o-aminothiophenol, m-aminothiophenol, 2-methyl-4-aminothiophenol, 3-methyl-4-aminothiophenol, 2-methyl-3-aminothiophenol, 3-methyl-2-aminothiophenol, 4-amino-3-trifluoromethylthiophenol, 4-amino-2-trifluoromethylthiophenol, 3-amino-2-trifluoromethylthiophenol, tetramethyl-p-aminothiophenol, and 2-amino-3-trifluoromethylthiophenol.

[0019] The present invention also provides a method for preparing the novel epoxy resin containing imide units, which comprises the following steps:

[0020] Step (1): Add the dibasic acid anhydride to a three-necked flask equipped with a water separator and a condensing reflux device, add the carboxylic acid solvent under an argon atmosphere and start mechanical stirring, add compound E and cyclohexane in sequence and heat to reflux, reflux for 10 to 20 hours, then cool to 20 to 30° C., pour the reaction solution into distilled water to precipitate, filter, wash the filter cake with distilled water 2 to 3 times, and vacuum dry at 60 to 120° C. to obtain a powder product A;

[0021] The molar ratio of the dibasic acid anhydride to the compound E is 1:2.05-2.15;

[0022] The molar ratio of the compound E to the carboxylic acid solvent is 1:100-150;

[0023] The volume ratio of the cyclohexane to the carboxylic acid solvent is 1:3-8;

[0024] Step (2): adding the prepared powder product A, epoxyhalogenated propane, iodide and carbonate compound to a reactor in sequence, adding solvent L under an argon atmosphere, stirring, and heating the system to reflux; after reflux reaction for 10 to 15 hours, cooling to 20 to 30° C., filtering out insoluble matter, concentrating the filtrate to remove solvent L, and obtaining a novel epoxy resin containing an imide unit after recrystallization;

[0025] The molar ratio of the powder product A to the epihalohydrin is 1:5 to 15;

[0026] The molar ratio of the carbonate compound to the epihalopropane is 1 to 3:1;

[0027] The molar ratio of the epihalohydrin to the iodide is 1:0.1 to 0.8;

[0028] The mass fraction of the powder product A in the solvent L is 5% to 20%.

[0029] Furthermore, in the preparation method of the novel epoxy resin containing imide units, the compound E can be prepared by the following steps:

[0030] (S1): Add nitro compound D and solvent C into the reactor in sequence and stir to dissolve under nitrogen atmosphere;

[0031] The mass of the solvent C used to dissolve the nitro compound D is 2 to 4 times the mass of the nitro compound D;

[0032] A carbonate compound is added to the reaction system and the system is heated to 60-90° C. and stirred for 0.5-2.0 hours. Then, a diphenol compound previously dissolved in solvent C is dropwise added to the reaction system over 0.5-2 hours. After the addition is completed, the temperature of the reaction system is raised to 100-140° C., the reaction is continued for 10-25 hours, and then cooled to 10-30° C. The reaction solution is poured into distilled water to precipitate, filtered, and the filter cake is washed with distilled water 2-3 times and dried in a vacuum oven at 50-120° C. for 12-24 hours to obtain product H.

[0033] The molar ratio of the nitro compound D to the dihydric phenol compound is 1:0.7-1.5;

[0034] The molar ratio of the nitro compound D to the carbonate compound is 1:1 to 2.5;

[0035] The mass of the solvent C used to dissolve the dihydric phenol compound is 2 to 4 times the mass of the dihydric phenol compound;

[0036] (S2): dissolving the product H in a solvent J, adding a palladium-carbon catalyst and a phosphorus-containing stabilizer, and placing the reaction system in a high-pressure reactor at 20-60° C. in a hydrogen atmosphere for 15-20 hours. During the reaction, the hydrogen pressure is maintained at 5-35 bar;

[0037] The mass fraction of product H in the hydrogenation reduction system is 10%-20%;

[0038] The mass fraction of the phosphorus-containing stabilizer is 0.5%-2%;

[0039] The amount of palladium-carbon catalyst added is determined based on 1 mmol of nitro group corresponding to 20 to 50 mg of palladium-carbon catalyst;

[0040] After the reaction is completed, the catalyst is filtered off, the solvent J is removed by distillation under reduced pressure, and the product is washed with toluene 2 to 3 times and then dried in a vacuum oven at 50 to 100° C. for 12 to 24 hours to obtain a monophenol compound E.

[0041] Further, the nitro compound D is any one of p-nitrohalobenzene, 2-methyl-4-nitrohalobenzene, 3-methyl-4-nitrohalobenzene, 4-nitro-3-trifluoromethylhalobenzene, 4-nitro-2-trifluoromethylhalobenzene, or a combination thereof; the halogenated element is fluorine, chlorine, bromine, or iodine;

[0042] The method for preparing the novel epoxy resin containing imide units is characterized in that the solvent C is any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide, or a combination thereof;

[0043] The carbonate compound is any one of sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate, or a combination thereof;

[0044] The phosphorus-containing stabilizer is any one of triphenyl phosphite, triphenyl phosphate, triphenyl phosphine, triphenyl phosphine oxide, or a combination thereof;

[0045] The solvent J is any one of methanol, tetrahydrofuran, ethyl acetate, acetonitrile, dichloromethane, chloroform, isopropanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, or a combination thereof;

[0046] The iodide is any one of potassium iodide, sodium iodide, rubidium iodide, and cesium iodide, or a combination thereof;

[0047] The carboxylic acid solvent is any one of formic acid, acetic acid, propionic acid, trifluoroacetic acid, perfluoropropionic acid, trichloroacetic acid, trichloropropionic acid, and trifluoropropionic acid, or a combination thereof;

[0048] The solvent L is any one of acetone, methyl ethyl ketone, acetonitrile, diethyl ketone, and methyl propyl ketone, or a combination thereof;

[0049] Furthermore, in the preparation method of the novel epoxy resin containing imide units, the dihydric phenol compound is any one or a combination of the following compounds, and the chemical structure is as follows:

[0050]

[0051] The present invention also provides use of the epoxy resin containing imide units as described above or the epoxy resin containing imide units prepared by the method for preparing epoxy resin materials.

[0052] Beneficial effects

[0053] The technical solution provided by the present invention has the following beneficial effects:

[0054] The present invention introduces rigid and highly polar imide units into the main chain of EP resin molecules through targeted molecular structure design, develops a novel synthesis method for EP resin, realizes the hybridization of imide and EP resin at the molecular level, and utilizes the strong polarity and high rigidity of the imide units to improve the impact toughness of the cured EP resin.

[0055] The rigid imide unit has outstanding thermal and oxidative stability, and the introduction of EP resin can also achieve the regulation of heat resistance, so that the EP resin developed by this technology can meet the requirements of the resin matrix for advanced resin-based composite materials.

[0056] Furthermore, the technical solution proposed in this invention not only improves the impact toughness of cured EP resin and enhances its thermal properties by leveraging the strong polarity and high heat resistance of the imide moiety, but also allows for the introduction of substituents such as methyl, phenyl, trifluoromethyl, and isopropyl into the EP resin molecular structure, as well as the introduction of twisted non-coplanar moieties or bulky substituents into the imide moiety, enabling flexible regulation of the EP resin's crystallinity, solubility, hygroscopicity, weatherability, melt viscosity, processability, and manufacturability. This technical approach proposed in this invention can provide diverse design ideas and raw material foundations for the molecular structure design and preparation of new EP resins, helping to promote and further deepen the widespread application of EP resins in extreme environments such as aerospace. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a schematic diagram of the synthetic route of phenolic compounds containing nitro groups;

[0058] Figure 2 This is a schematic diagram of the synthetic route of phenolic compounds containing amino groups;

[0059] Figure 3 This is a schematic diagram of the synthetic route of diphenolic compounds containing imide moieties;

[0060] Figure 4 Schematic diagram of the preparation route of epoxy resin containing imide unit;

[0061] Figure 5 This is a real photo of epoxy resin containing imide units;

[0062] Figure 6 is the H NMR spectrum of the epoxy resin prepared in Example 10 in CDCl3;

[0063] Figure 7 is the carbon NMR spectrum of the epoxy resin prepared in Example 10 in DMSO-d6;

[0064] Figure 8 is a high-resolution mass spectrum of the epoxy resin prepared in Example 10;

[0065] Figure 9 This is the thermogravimetric curve of the epoxy resin prepared in Example 8 in a nitrogen atmosphere;

[0066] Figure 10 The DSC curve of the epoxy resin prepared in Example 6 is shown in FIG. m =183℃. DETAILED DESCRIPTION

[0067] The present invention is described in detail by the following examples. It should be understood that the following examples are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered by the scope of protection of the present invention, and all compositions based on the core substance of the present invention as the main component are within the scope of protection of the present invention.

[0068] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or prepared by known methods.

[0069] Example 1

[0070] 20.20 g of p-bromonitrobenzene was dissolved in 50.00 g of N-methylpyrrolidone and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 10.60 g of sodium carbonate was added to the solution and heated with stirring at 75°C for 1 h. Then, 7.01 g of hydroquinone dissolved in 28.04 g of N-methylpyrrolidone was dropped into the three-necked flask. After complete addition, the system temperature was raised to 120°C, maintained at this temperature for 12 h, and then cooled to 20°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered off with suction, and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain product H with a yield of 91.9%. 23.12 g of product H was dissolved in 230 g of tetrahydrofuran, 5 g of palladium-carbon catalyst and 2.6 mL of triphenylphosphite were added, and the reaction system was placed in an autoclave and reacted at 20°C in a hydrogen atmosphere for 18 hours. The hydrogen pressure was maintained at 12 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 80°C for 12 hours to obtain monophenol compound E. 22.21 g of 6FDA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux device. 450 g of acetic acid was added under an argon atmosphere and mechanical stirring was started. 15.09 g of monophenol compound E and 150 mL of cyclohexane were added in sequence, and the system was heated to reflux. After reflux for 16 hours, the reaction mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 95%. 8.107g of product A, 9.68g of anhydrous potassium carbonate, 4.98g of potassium iodide, and 6.97g of epibromopropane were added to a three-necked flask. Under argon protection, 405g of acetone was added and mechanical stirring was started. The system was heated to reflux. After reflux for 16 hours, the reaction mixture was cooled to 25°C, the insoluble matter was filtered off, and the acetone was removed by vacuum distillation. After recrystallization, a new epoxy resin containing imide units was obtained with a yield of 89.7%.

[0071] Example 2

[0072] 21.60 g of 2-bromo-4-nitrotoluene was dissolved in 60.00 g of N,N-dimethylformamide and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 32.60 g of cesium carbonate was added to the solution and heated with stirring at 85°C for 0.75 h. Then, 14.15 g of 4,4'-dihydroxydiphenyl ether dissolved in 56.60 g of N,N-dimethylformamide was dropped into the three-necked flask. After complete addition, the system temperature was raised to 115°C, maintained at this temperature for 16 h, and then cooled to 25°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 75°C for 18 h to obtain product H with a yield of 89.6%. 32.82 g of product H was dissolved in 328 g of tetrahydrofuran, 5 g of palladium-carbon catalyst and 3.7 mL of triphenylphosphite were added, and the reaction system was placed in an autoclave and reacted at 30°C under a hydrogen atmosphere for 14 h. The hydrogen pressure was maintained at 10 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 85°C for 16 h to obtain monophenol compound E. 14.71 g of a-BPDA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 450 g of acetic acid was added under argon atmosphere with mechanical stirring. 29.42 g of monophenol compound E and 150 mL of cyclohexane were added in sequence, and the system was heated to reflux. After 16 hours of reflux, the reaction mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 97.1%. 8.46g of product A, 9.68g of anhydrous potassium carbonate, 4.5g of sodium iodide, and 4.63g of epichlorohydrin were added to a three-necked flask. Under argon protection, 423g of acetonitrile was added and mechanical stirring was started. The system was heated to reflux. After reflux for 17 hours, the reaction mixture was cooled to 25°C, the insoluble matter was filtered off, and the acetonitrile was removed by vacuum distillation. After recrystallization, a new epoxy resin containing imide units was obtained with a yield of 92.0%.

[0073] Example 3

[0074] 22.50 g of 4-trifluoromethylbromobenzene was dissolved in 50.00 g of N,N-dimethylacetamide and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 13.82 g of potassium carbonate was added to the solution and heated with stirring at 75°C for 0.5 h. Then, 17.52 g of 4,4'-thiobisthiophenol dissolved in 70.04 g of N,N-dimethylacetamide was dropped into the three-necked flask. After complete addition, the system temperature was raised to 105°C, maintained at this temperature for 12 h, and then cooled to 30°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 85°C for 18 hours to obtain product H with a yield of 91.2%. 38.5 g of product H was dissolved in 385 g of tetrahydrofuran, 5 g of palladium-carbon catalyst and 4.3 mL of triphenylphosphite were added, and the reaction system was placed in an autoclave and reacted at 40°C in a hydrogen atmosphere for 17 hours. The hydrogen pressure was maintained at 12 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 75°C for 14 hours to obtain monophenol compound E. 15.50 g of ODPA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 450 g of acetic acid was added under an argon atmosphere with mechanical stirring. 18.13 g of monophenol compound E and 150 mL of cyclohexane were added in sequence, and the system was heated to reflux. After 17 hours of reflux, the reaction mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 97.9%. 9.67g of product A, 9.68g of anhydrous potassium carbonate, 4.5g of sodium iodide, and 4.63g of epichlorohydrin were added to a three-necked flask. Under argon protection, 483.5g of acetonitrile was added and mechanical stirring was started. The system was heated to reflux. After reflux for 17 hours, the reaction mixture was cooled to 25°C, the insoluble matter was filtered off, the acetonitrile was removed by vacuum distillation, and the new epoxy resin containing imide units was obtained after recrystallization with a yield of 92.0%.

[0075] Example 4

[0076] 20.20 g of p-bromonitrobenzene was dissolved in 80.80 g of N-methylpyrrolidone and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 21.2 g of sodium carbonate was added to the solution and heated with stirring at 75°C for 1 h. Then, 15.02 g of hydroquinone dissolved in 30.04 g of N-methylpyrrolidone was dropped into the three-necked flask. After complete addition, the system temperature was raised to 120°C, maintained at this temperature for 12 h, and then cooled to 20°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered off with suction, and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain product H with a yield of 91.9%. 23.12 g of product H was dissolved in 230 g of tetrahydrofuran, 10 g of palladium-carbon catalyst and 1.3 mL of triphenylphosphite were added, and the reaction system was placed in an autoclave and reacted at 50°C in a hydrogen atmosphere for 18 hours. The hydrogen pressure was maintained at 12 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 80°C for 12 hours to obtain monophenol compound E. 22.21 g of 6FDA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 675 g of acetic acid was added under an argon atmosphere and mechanical stirring was initiated. 25.15 g of monophenol compound E and 84.4 mL of cyclohexane were added in sequence, and the system was heated to reflux. After 16 hours of reflux, the reaction mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 95%. 8.107g of product A, 17.97g of anhydrous potassium carbonate, 11.62g of potassium iodide, and 20.91g of epibromopropane were added to a three-necked flask. Under argon protection, 81g of acetone was added and mechanical stirring was started. The system was heated to reflux. After reflux for 16 hours, the mixture was cooled to 25°C, the insoluble matter was filtered off, the acetone was removed by vacuum distillation, and the new epoxy resin containing imide units was obtained after recrystallization with a yield of 89.7%.

[0077] Example 5

[0078] 21.60 g of 2-bromo-4-nitrotoluene was dissolved in 86.4 g of N,N-dimethylformamide and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 65.2 g of cesium carbonate was added to the solution and heated with stirring at 85°C for 0.75 h. Then, 28.30 g of 4,4'-dihydroxydiphenyl ether dissolved in 56.60 g of N,N-dimethylformamide was dropped into the three-necked flask. After complete addition, the system temperature was raised to 115°C, maintained at this temperature for 16 h, and then cooled to 25°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 75°C for 18 hours to obtain product H with a yield of 89.6%. 32.82 g of product H was dissolved in 164 g of tetrahydrofuran, 10 g of palladium-carbon catalyst and 1.8 mL of triphenylphosphite were added, and the reaction system was placed in an autoclave and reacted at 40°C in a hydrogen atmosphere for 14 hours. The hydrogen pressure was maintained at 10 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 85°C for 16 hours to obtain monophenol compound E. 14.71 g of a-BPDA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 675 g of acetic acid was added under argon atmosphere with mechanical stirring. 49.03 g of monophenol compound E and 84.4 mL of cyclohexane were added in sequence, and the system was heated to reflux. After 16 hours of reflux, the reaction mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered Product A with a yield of 97.1%. 8.46g of Product A, 17.97g of anhydrous potassium carbonate, 10.5g of sodium iodide, and 13.89g of epichlorohydrin were added to a three-necked flask. Under argon protection, 84.6g of acetonitrile was added and mechanical stirring was initiated. The system was heated to reflux. After reflux for 17 hours, the mixture was cooled to 25°C, the insoluble matter was filtered off, the acetonitrile was removed by vacuum distillation, and the novel epoxy resin containing imide units was obtained after recrystallization with a yield of 92.0%.

[0079] Example 6

[0080] 22.50 g of 4-trifluoromethylbromobenzene was dissolved in 90 g of N,N-dimethylacetamide and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 27.64 g of potassium carbonate was added to the solution and heated with stirring at 75°C for 0.5 h. Then, 35.04 g of 4,4'-thiobisthiophenol dissolved in 70.08 g of N,N-dimethylacetamide was dropped into the three-necked flask. After complete addition, the system temperature was raised to 105°C, maintained at this temperature for 12 h, and then cooled to 30°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 85°C for 18 hours to obtain product H with a yield of 91.2%. 38.5 g of product H was dissolved in 192.5 g of tetrahydrofuran, 10 g of palladium-carbon catalyst and 2.1 mL of triphenylphosphite were added, and the reaction system was placed in an autoclave and reacted at 60°C in a hydrogen atmosphere for 17 hours. The hydrogen pressure was maintained at 12 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 75°C for 14 hours to obtain monophenol compound E. 26.00 g of BPADA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 675 g of acetic acid was added under an argon atmosphere with mechanical stirring. 30.21 g of monophenol compound E and 84.4 mL of cyclohexane were added in sequence, and the system was heated to reflux. After 17 hours of reflux, the reaction mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 97.9%. 9.67g of product A, 17.97g of anhydrous potassium carbonate, 10.5g of sodium iodide, and 13.89g of epichlorohydrin were added to a three-necked flask. Under argon protection, 96.6g of acetonitrile was added and mechanical stirring was started. The system was heated to reflux. After reflux for 17 hours, the mixture was cooled to 25°C, the insoluble matter was filtered off, the acetonitrile was removed by vacuum distillation, and the new epoxy resin containing imide units was obtained after recrystallization with a yield of 92.0%.

[0081] Example 7

[0082] 20.20 g of p-bromonitrobenzene was dissolved in 40.4 g of N-methylpyrrolidone and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 10.70 g of sodium carbonate was added to the solution and heated with stirring at 75°C for 1 h. Then, 11.01 g of hydroquinone dissolved in 30.00 g of N-methylpyrrolidone was dropped into the three-necked flask. After complete addition, the system temperature was raised to 120°C, maintained at this temperature for 12 h, and then cooled to 20°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain product H with a yield of 91.9%. 23.12 g of product H was dissolved in 230 g of tetrahydrofuran, 7.5 g of palladium-carbon catalyst and 2.2 mL of triphenylphosphine oxide were added, and the reaction system was placed in an autoclave and reacted at 50°C in a hydrogen atmosphere for 18 hours. The hydrogen pressure was maintained at 12 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 80°C for 12 hours to obtain monophenol compound E. 22.21 g of 6FDA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux device. 500 g of acetic acid was added under an argon atmosphere and mechanical stirring was started. 22.13 g of monophenol compound E and 100 mL of cyclohexane were added in sequence, and the system was heated to reflux. After reflux for 16 hours, the mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 95%. 8.107g of product A, 12.13g of anhydrous potassium carbonate, 6.73g of potassium iodide, and 14.52g of epibromopropane were added to a three-necked flask. Under argon protection, 300g of acetone was added and mechanical stirring was started. The system was heated to reflux. After reflux for 16 hours, the mixture was cooled to 25°C, the insoluble matter was filtered off, the acetone was removed by vacuum distillation, and the new epoxy resin containing imide units was obtained after recrystallization with a yield of 89.7%.

[0083] Example 8

[0084] 21.60 g of 2-bromo-4-nitrotoluene was dissolved in 43.20 g of N,N-dimethylformamide and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 34.25 g of cesium carbonate was added to the solution and heated with stirring at 85°C for 0.75 h. Then, 20.17 g of 4,4'-dihydroxydiphenyl ether dissolved in 45.00 g of N,N-dimethylformamide was dropped into the three-necked flask. After complete addition, the system temperature was raised to 115°C, maintained at this temperature for 16 h, and then cooled to 25°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 75°C for 18 h to obtain product H with a yield of 89.6%. 32.82 g of product H was dissolved in 300 g of tetrahydrofuran, 7.9 g of palladium-carbon catalyst and 2.7 mL of triphenylphosphine oxide were added, and the reaction system was placed in an autoclave and reacted at 30°C in a hydrogen atmosphere for 14 h. The hydrogen pressure was maintained at 10 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 85°C for 16 h to obtain monophenol compound E. 14.71 g of a-BPDA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 600 g of acetic acid was added under argon atmosphere with mechanical stirring. 37.16 g of monophenol compound E and 110 mL of cyclohexane were added in sequence, and the system was heated to reflux. After reflux for 16 hours, the reaction mixture was slowly cooled to 25°C. The precipitate was then filtered and washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain a powdered product A with a yield of 97.1%. Under argon, 8.46g of product A, 13.66g of anhydrous potassium carbonate, 7.30g of sodium iodide, and 10.20g of epichlorohydrin were added to 260g of acetonitrile with mechanical stirring. The system was heated to reflux. After reflux for 17 hours, the reaction mixture was cooled to 25°C, the insoluble matter was filtered off, and the acetonitrile was removed by vacuum distillation. After recrystallization, a new epoxy resin containing imide units was obtained with a yield of 92.0%.

[0085] Example 9

[0086] 22.50 g of 4-trifluoromethylbromobenzene was dissolved in 45.00 g of N,N-dimethylacetamide and added to a three-necked flask equipped with a reflux condenser. The mixture was stirred and dissolved under a nitrogen atmosphere. Subsequently, 14.73 g of potassium carbonate was added to the solution and heated with stirring at 75°C for 0.5 h. Then, 25.36 g of 4,4'-thiobisthiophenol dissolved in 55.23 g of N,N-dimethylacetamide was dropped into the three-necked flask. After complete addition, the system temperature was raised to 105°C, maintained at this temperature for 12 h, and then cooled to 30°C. The reaction solution was poured into distilled water to precipitate the precipitate, which was then filtered and the filter cake was washed 2-3 times with distilled water. The filter cake was dried in a vacuum oven at 85°C for 18 h to obtain product H with a yield of 91.2%. 38.5 g of product H was dissolved in 225 g of tetrahydrofuran, 7.3 g of palladium-carbon catalyst and 2.7 mL of triphenylphosphite were added, and the reaction system was placed in an autoclave and reacted at 20°C in a hydrogen atmosphere for 17 h. The hydrogen pressure was maintained at 12 bar during the reaction. After the reaction, the catalyst was filtered off, the tetrahydrofuran solvent was removed by vacuum distillation, and the product was washed 2-3 times with toluene and dried in a vacuum oven at 75°C for 14 h to obtain monophenol compound E. 15.50 g of a-ODPA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 550 g of acetic acid was added under argon atmosphere and mechanical stirring was initiated. 22.42 g of monophenol compound E and 100 mL of cyclohexane were added in sequence, and the system was heated to reflux. After 17 hours of reflux, the reaction mixture was slowly cooled to 25°C. The reaction mixture was poured into distilled water to precipitate the precipitate, filtered, and the filter cake washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 97.9%. 9.67g of product A, 10.36g of anhydrous potassium carbonate, 7.20g of sodium iodide, and 11.83g of epichlorohydrin were added to a three-necked flask. Under argon protection, 320.5g of acetonitrile was added and mechanical stirring was started. The system was heated to reflux. After reflux for 17 hours, the reaction mixture was cooled to 25°C, the insoluble matter was filtered off, the acetonitrile was removed by vacuum distillation, and recrystallization was performed to obtain a novel epoxy resin containing imide units with a yield of 92.0%.

[0087] Example 10

[0088] 11.10g of 6FDA was added all at once to a three-necked flask equipped with a water separator and a condenser reflux apparatus. 200g of acetic acid was added under an argon atmosphere and mechanical stirring was started. 5.45g of p-aminophenol and 50mL of cyclohexane were added sequentially and the system was heated to reflux. After reflux reaction for 18 hours, the mixture was slowly cooled to 25°C. The reaction solution was poured into distilled water to precipitate, filtered, and the filter cake was washed three times with distilled water. The filter cake was dried in a vacuum oven at 80°C for 24 hours to obtain powdered product A with a yield of 96.9%. 9.67 g of product A, 20.72 g of anhydrous potassium carbonate, 12.45 g of potassium iodide, and 20.70 g of epichlorohydrin were added to a three-necked flask. Under argon protection, 300 g of acetone was added and mechanical stirring was started. The system was heated to reflux. After reflux reaction for 17 hours, it was cooled to 25°C, the insoluble matter was filtered off, and the acetone was removed by vacuum distillation. After recrystallization, a new epoxy resin containing imide units was obtained with a yield of 91.7%.

[0089] Example 11

[0090] The mechanical and thermal properties of the cured EP resin prepared in the present invention are shown in Table 1, which are compared with those of some commercial brands or cured EP resins reported by some research groups.

[0091] Table 1. Comparison of impact properties (critical stress intensity factor) and thermal properties of EP resins prepared in the present invention and cured products of other brands of EP resins:

[0092]

[0093]

[0094] As shown in the table above, the resin material provided by the present invention exhibits a significantly improved critical stress intensity factor (K IC ), up to 2.03MPa·m 1 / 2 The elongation at break exceeds 6%, while the glass transition temperature and the 5% thermal decomposition temperature do not decrease, and even show a slight increase. This shows that the technical solution claimed in the present invention has significant advantages in improving the impact toughness of EP resin.

[0095] The above embodiments illustrate exemplary implementations of the present invention. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. An epoxy resin containing an imide unit, characterized in that: The molecular structure of the epoxy resin is represented by the following general formula (I): Formula (I) Wherein, the molar ratio of the dibasic acid anhydride part, the compound E part and the epihalogenated propane part in formula (I) is 1:2:2; R1 represents O or S; R2 represents a residue in compound E, R2 is a substituted or unsubstituted phenylene group, or is the following structural fragment represented by formula (II): Formula (II), Wherein, R* in formula (II) is a residue in a diphenol compound, and R* is connected to R1 in formula (I); M1 is O or S, Y is H, -CF3 or -CH3; and R3 represents a residue in a dibasic acid anhydride.

2. The epoxy resin containing imide units according to claim 1, characterized in that: The dibasic acid anhydride portion corresponds to any one or a combination of the following acid anhydrides, and the chemical structure is as follows: 。 3. The epoxy resin containing imide units according to claim 1, characterized in that: The epihalohydrin is any one of epifluorohydrin, epichlorohydrin, epibromohydrin, and epiiodohydrin, or a combination thereof.

4. An epoxy resin containing imide units according to any one of claims 1 to 3, characterized in that: The aminophenols contained in the compounds corresponding to the compound E part are: p-aminophenol, o-aminophenol, m-aminophenol, 2-methyl-4-aminophenol, tetramethyl-p-aminophenol, 3-methyl-4-aminophenol, 2-methyl-3-aminophenol, 3-methyl-2-aminophenol, 4-amino-3-trifluoromethylphenol, 4-amino-2-trifluoromethylphenol, 3-amino-2-trifluoromethylphenol, 2-phenyl-4-aminophenol, 3-isopropyl-4-aminophenol, 2-phenyl-3-aminophenol, 3-isopropyl-2-aminophenol, 3-phenyl-4-aminophenol, 3-phenyl-2-aminophenol, 2-amino-3-trifluoromethylphenol, p-aminothiophenol, o-aminothiophenol, m-aminothiophenol, 2-methyl-4-aminothiophenol, 3-methyl-4-aminothiophenol, 2-methyl-3-aminothiophenol, 3-methyl-2-aminothiophenol, 4-amino-3-trifluoromethylthiophenol, 4-amino-2-trifluoromethylthiophenol, 3-amino-2-trifluoromethylthiophenol, tetramethyl-p-aminothiophenol, 2-amino-3-trifluoromethylthiophenol or any combination thereof.

5. A method for preparing the epoxy resin containing imide units according to claims 1-4, characterized in that The specific steps are as follows: Step (1): Add dibasic acid anhydride to a reactor, add carboxylic acid solvent under argon atmosphere, stir, add compound E and cyclohexane in sequence, and heat to reflux. After reflux reaction for 10 to 20 hours, cool to 20 to 30 °C, pour the reaction solution into distilled water to precipitate, filter, wash the filter cake with distilled water 2 to 3 times, and vacuum dry at 60 to 120 °C to obtain powder product A; The molar ratio of the dibasic acid anhydride to compound E is 1:2.05-2.15; The molar ratio of the compound E to the carboxylic acid solvent is 1:100-150; The volume ratio of the cyclohexane to the carboxylic acid solvent is 1:3-8; Step (2): The obtained powder product A, epihalogenated propylene oxide, iodide and carbonate compound were added to the reactor in sequence, and solvent L was added under argon atmosphere, stirred, and the system was heated to reflux; after reflux reaction for 10-15 hours, the mixture was cooled to 20-30 ° C, the insoluble matter was filtered out, the filtrate was concentrated to remove solvent L, and the epoxy resin containing imide units was obtained after recrystallization; The molar ratio of the powder product A to the epihalohydrin is 1:5-15; The molar ratio of the carbonate compound to the epihalogenated propane is 1 to 3:1; The molar ratio of the epihalohydrin to the iodide is 1:0.1-0.8; The mass fraction of the powder product A in the solvent L is 5% to 20%.

6. The method for preparing an epoxy resin containing an imide unit according to claim 5, wherein The compound E can be prepared by the following steps: (S1): adding a nitro compound D and a solvent C into a reactor, stirring and dissolving them under a nitrogen atmosphere; the mass of the solvent C used to dissolve the nitro compound D is 2 to 4 times the mass of the nitro compound D; A carbonate compound is added to the reaction system and the system is heated to 60-90°C and stirred for 0.5-2.0 h. Then, a diphenol compound previously dissolved in solvent C is added dropwise to the reaction system over 0.5-2 h. After the addition is completed, the temperature of the reaction system is raised to 100-140°C, the reaction is continued for 10-25 h, and then cooled to 10-30°C. The reaction solution is poured into distilled water to precipitate, which is filtered with suction. The filter cake is washed with distilled water 2-3 times and dried in a vacuum oven at 50-120°C for 12-24 h to obtain product H. The molar ratio of the nitro compound D to the dihydric phenol compound is 1:0.7-1.5; The molar ratio of the nitro compound D to the carbonate compound is 1:1 to 2.5; The mass of the solvent C used to dissolve the dihydric phenol compound is 2 to 4 times the mass of the dihydric phenol compound; (S2): dissolving the obtained product H in solvent J, adding a palladium-carbon catalyst and a phosphorus-containing stabilizer, and placing the reaction system in a high-pressure reactor at 20-60 °C in a hydrogen atmosphere for 15-20 h. During the reaction, the hydrogen pressure is maintained at 5-35 bar. The mass fraction of product H in the hydrogenation reduction system is 10%-20%; The mass fraction of the phosphorus-containing stabilizer is 0.5%-2%; The amount of the palladium-carbon catalyst added is determined based on 1 mmol of nitro group corresponding to 20-50 mg of palladium-carbon catalyst; After the reaction, the catalyst was filtered off, the solvent J was removed by distillation under reduced pressure, and the product was washed with toluene 2-3 times and dried in a vacuum oven at 50-100°C for 12-24 h to obtain a monophenol compound E.

7. The method for preparing an epoxy resin containing an imide unit according to claim 5 or 6, wherein: The nitro compound D is any one of p-nitrohalobenzene, 2-methyl-4-nitrohalobenzene, 3-methyl-4-nitrohalobenzene, 4-nitro-3-trifluoromethylhalobenzene, and 4-nitro-2-trifluoromethylhalobenzene, or a combination thereof; the halogenated element is fluorine, chlorine, bromine, or iodine.

8. The method for preparing an epoxy resin containing an imide unit according to claim 5 or 6, characterized in that: The solvent C is any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide, or a combination thereof; The carbonate compound is any one of sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate, or a combination thereof; The phosphorus-containing stabilizer is any one of triphenyl phosphite, triphenyl phosphate, triphenyl phosphine, triphenyl phosphine oxide, or a combination thereof; The solvent J is any one of methanol, tetrahydrofuran, ethyl acetate, acetonitrile, dichloromethane, chloroform, isopropanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, or a combination thereof; The iodide is any one of potassium iodide, sodium iodide, rubidium iodide, and cesium iodide, or a combination thereof; The carboxylic acid solvent is any one of formic acid, acetic acid, propionic acid, trifluoroacetic acid, perfluoropropionic acid, trichloroacetic acid, trichloropropionic acid, and trifluoropropionic acid, or a combination thereof; The solvent L is any one of acetone, methyl ethyl ketone, acetonitrile, diethyl ketone, and methyl propyl ketone, or a combination thereof.

9. The method for preparing an epoxy resin containing an imide unit according to claim 5 or 6, characterized in that The dihydric phenol compound is any one of the following compounds or a combination thereof, and the chemical structural formula is as follows: 。 10. Use of the epoxy resin containing imide units according to any one of claims 1 to 4 or the epoxy resin containing imide units prepared by the method according to any one of claims 5 to 9 in preparing epoxy resin materials.

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