Benzoxazine-containing amine curing agent, epoxy resin composition and use thereof

Abstract

The application discloses a benzoxazine-containing amine curing agent, which comprises repeated daidzein-based benzoxazine structural units and can be prepared through a Mannich reaction. The application also discloses an epoxy resin composition, which comprises an epoxy resin precursor, the above-mentioned benzoxazine-containing amine curing agent and a curing accelerator. After gradient curing, the epoxy resin composition obtains an epoxy resin cured product. Compared with an epoxy resin cured product prepared by using a commonly used curing agent (4,4-diaminodiphenyl methane), the epoxy resin cured product prepared by using the benzoxazine-containing amine curing agent has a higher limiting oxygen index and reaches a V-0 level, and has excellent flame-retardant performance. Meanwhile, in a combustion experiment, the epoxy resin cured product prepared by using the benzoxazine-containing amine curing agent has a small total smoke release amount, a small maximum smoke density and a low CO generation amount, has a low smoke and toxicity characteristic, and is suitable for application fields with high heat resistance, high strength and flame-retardant low smoke and toxicity requirements.

Description

Technical Field

[0001] This invention relates to the field of benzoxazine materials technology, specifically to an amine curing agent containing benzoxazine, an epoxy resin composition, and their applications. Background Technology

[0002] Epoxy resin is one of the most widely used thermosetting resins. Due to its high adhesion, excellent chemical resistance, superior mechanical properties, and ease of processing, it is widely used as a matrix for adhesives, coatings, and fiber composites in transportation, construction, and aerospace. However, traditional epoxy resins have poor flame retardancy and excessive smoke toxicity. Furthermore, when used as coatings or paints, they often cause large-scale bacterial growth and viral contamination due to bacterial contaminant adhesion.

[0003] Benzoxazine resin, as a novel thermosetting resin, is disclosed in Chinese patent document CN119060332A, which describes a halogen-free and phosphorus-free flame-retardant modified benzoxazine resin and its preparation method. The resin is obtained by blending and heating with one or more benzoxazine monomers and one or more aldehyde compounds as raw materials. The benzoxazine monomers are bisphenol-type, diamine-type, triphenol-type, or triamine-type benzoxazine monomers. Due to its near-zero curing yield, absence of small molecule byproducts during curing, excellent chemical resistance, thermal stability, and superior flame retardancy and low smoke toxicity, it is widely used in aerospace, electronic packaging, and rail transportation.

[0004] Genistein is a renewable compound found in soybeans and other legumes, making it environmentally friendly. Benzooxazine resins based on this renewable resource are also environmentally friendly. Genistein possesses a benzopyranone structure, exhibiting excellent char-forming properties, which can improve the thermomechanical properties of thermosetting resins. Furthermore, genistein possesses various biological activities, such as antibacterial and antioxidant properties, and is widely used in the pharmaceutical industry. Chinese patent document CN110894274A discloses a bio-based main-chain benzooxazine resin based on genistein and its preparation method. The preparation method includes: uniformly mixing genistein, furfurylamine, a diamine compound, and paraformaldehyde, followed by a Mannich polymerization reaction under heating conditions.

[0005] In recent years, epoxy resins have been widely used in flame retardancy and other applications due to their excellent properties. Inspired by this, domestic and foreign scholars have introduced benzoxazine resins into the crosslinking network of epoxy resins to prepare a series of novel materials with excellent flame retardant and low smoke toxicity properties. However, epoxy resins are prone to brittle fracture under high stress conditions, which limits their service life in some applications. Therefore, how to maintain the high strength of epoxy resins while further improving the flame retardant properties of cured epoxy resins is a key challenge in current technological development. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an amine curing agent containing benzoxazine. This amine curing agent contains daidzeinylbenzoxazine structural units and can be used in epoxy resin compositions, resulting in cured epoxy resin products with excellent flame retardant and low smoke toxicity properties.

[0007] An amine curing agent containing benzoxazine, comprising the following structural units:

[0008]

[0009] Where R is selected from For connection positions.

[0010] In this invention, the amine curing agent contains repeating daidzein benzoxazine structural units. Daidzein is a renewable compound found in soybeans and other legumes, making it environmentally friendly. Simultaneously, daidzein possesses a benzopyranone structure, exhibiting excellent char-forming properties, which can improve the flame-retardant performance of the resulting thermosetting resin. During the curing process, the benzoxazine rings in the curing agent undergo ring-opening polymerization to form a highly cross-linked network structure. This cross-linked structure endows the thermosetting resin with excellent thermal stability and mechanical properties.

[0011] The present invention also provides a method for preparing the above-mentioned amine curing agent. The method for preparing the amine curing agent is simple, easy to operate, and the reaction conditions are controllable. It is easy to implement and suitable for large-scale production.

[0012] A method for preparing an amine curing agent containing benzoxazine includes the following steps:

[0013] A benzoxazine-containing amine curing agent was prepared by mixing polyethylene polyamine, organic solvent, daidzein and paraformaldehyde and then reacting them via the Mannich reaction.

[0014] In this invention, the daidzein mentioned above is 7,4'-dihydroxyisoflavone, and its structure is shown below.

[0015]

[0016] The amino group of polyethylene polyamine attacks the carbonyl group of paraformaldehyde, undergoing a nucleophilic addition reaction to give an imine ion intermediate. The imine ion acts as an electrophile to attack the phenolic hydroxyl group of daidzein, thus giving an amine curing agent.

[0017] Preferably, the polyethylene polyamine is one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0018] Preferably, the organic solvent is at least one selected from dichloromethane, trichloromethane, N,N-dimethylformamide, dioxane, and anhydrous ethanol.

[0019] Preferably, the molar ratio of the polyethylene polyamine, daidzein, and paraformaldehyde is 1:1 to 1.3:4 to 4.8.

[0020] Preferably, the Mannich reaction temperature is 90–150°C and the reaction time is 8–24 h.

[0021] The present invention also provides an epoxy resin composition comprising an epoxy resin precursor, the above-mentioned benzoxazine-containing amine curing agent and curing accelerator.

[0022] The epoxy resin composition of this invention comprises an epoxy resin precursor, the aforementioned benzoxazine-containing amine curing agent, and a curing accelerator. After gradient curing, an epoxy resin cured product with excellent flame retardant and low smoke toxicity properties can be obtained. Since the amine curing agent contains a benzoxazine structure, the benzoxazine itself can be cured by heating. During the curing process, the benzoxazine ring undergoes a ring-opening polymerization reaction to form a highly cross-linked network structure, which can further improve the cross-linking density and thermodynamic properties of the cured epoxy resin product.

[0023] Preferably, the epoxy resin precursor is selected from any of the following structures:

[0024]

[0025] Where X, Y, and Z are each independently selected from any of the following structures:

[0026]

[0027] R1, R2, R3, and R4 are each independently selected from hydrogen, C1-C6 alkyl groups, C1-C6 alkoxy groups, phenyl groups, phenoxy groups, or C3-C7 cycloalkyl groups. For connection positions.

[0028] In this invention, the epoxy resin precursor used may be bisphenol A diglycidyl ether, diglycidyl terephthalate, p-phenylenediamine tetraglycidylamine, bisphenol A glycidyl ether, bisphenol S glycidyl ether, bisphenol S diglycidyl ether, bisphenol A epoxy resin, naphthylphenylenediamine tetraglycidylamine, bisphenol F glycidyl ether, etc.

[0029] Preferably, the ratio of the epoxy equivalent value in the epoxy resin precursor to the active hydrogen equivalent value of the benzoxazine-containing amine curing agent is 10:1 to 10.

[0030] Preferably, the curing accelerator is at least one selected from tertiary amines, tertiary amine salts, quaternary ammonium salts, imidazole compounds, organophosphorus compounds, acetylacetone metal salts, carboxylic acid metal salts, and boron trifluoride amine complexes.

[0031] In this invention, the curing accelerator may be triethanolamine, dodecylamine, zinc acetylacetone, triphenylphosphine, tetrabutylammonium iodide, 2-methylimidazole, dimethylphenylamine, 2-methylimidazole, boron trifluoride ethylamine, hexadecyl dimethyl benzylammonium, manganese naphthenate, etc.

[0032] Preferably, the mass of the curing accelerator is 0.05% to 0.5% of the total mass of the epoxy resin precursor and the benzoxazine-containing amine curing agent.

[0033] The present invention also provides a method for preparing the above-mentioned epoxy resin composition, comprising the following steps: mixing an epoxy resin precursor and an amine curing agent containing benzoxazine evenly, heating, and adding a curing accelerator to obtain the composition.

[0034] The present invention also provides an epoxy resin cured product, which is obtained by gradient curing of the above-mentioned epoxy resin composition.

[0035] The epoxy resin composition of this invention is subjected to gradient curing to obtain a cured epoxy resin product. After testing, the cured epoxy resin product obtained by this invention has higher strength and thermal stability compared with the cured epoxy resin product prepared by a commonly used curing agent (4,4-diaminodiphenylmethane). Furthermore, the cured epoxy resin product obtained by this invention has a higher limiting oxygen index and reaches the V-0 level, exhibiting excellent flame retardant properties. At the same time, the cured epoxy resin product obtained by this invention has low total smoke release, low maximum smoke density, and low CO generation in combustion experiments, exhibiting low smoke toxicity.

[0036] Preferably, the gradient curing starts at 120°C and ends at 200°C.

[0037] More preferably, the gradient curing is performed by curing at 120°C for 2 hours, then at 140°C for 2 hours, then at 160°C for 2 hours, then at 180°C for 2 hours, and finally at 200°C for 2 hours.

[0038] Preferably, the limiting oxygen index of the epoxy resin cured product is 30% to 35%, and the flame retardant performance reaches V-0 level.

[0039] The limiting oxygen index (LOI) is used to evaluate the flammability of cured epoxy resins, determining how easily they burn when exposed to a flame in air. A higher LIO indicates better flame retardant properties. In this invention, an epoxy resin cured product is prepared by mixing and curing an amine curing agent containing benzoxazine with an epoxy resin precursor. This cured epoxy resin exhibits a high LIO and reaches a V-0 rating, demonstrating excellent flame retardant properties.

[0040] Preferably, the maximum smoke density of the epoxy resin cured product is 50-70 MJ / m³. 3 The CO generation rate is 0.06–0.08 g / g.

[0041] The epoxy resin cured product prepared in this invention exhibits low total smoke release, low maximum smoke density, and low CO generation in combustion experiments, thus possessing low smoke toxicity characteristics.

[0042] Preferably, the glass transition temperature of the epoxy resin cured product is 170–280°C.

[0043] In this invention, compared with epoxy resin cured products prepared by commonly used curing agent (4,4-diaminodiphenylmethane), the glass transition temperature of the epoxy resin cured product obtained by this invention is within the above-mentioned range, indicating that the epoxy resin cured product has a high crosslinking density and excellent thermodynamic properties.

[0044] This invention also provides applications of the above-mentioned epoxy resin cured products in the fields of composite materials and electronic packaging materials. The epoxy resin cured products obtained by this invention possess flame-retardant and low-smoke-toxicity properties, making them suitable for applications requiring high heat resistance, high strength, flame retardancy, and low smoke toxicity.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] (1) The present invention obtains a series of amine curing agents containing benzopyranone, benzoxazine and imino structures through the Mannich reaction. The preparation method is simple, the reaction conditions are controllable and easy to implement, and it is suitable for large-scale industrial production.

[0047] (2) The epoxy resin composition of the present invention comprises an epoxy resin precursor, the above-mentioned benzoxazine-containing amine curing agent and curing accelerator. After gradient curing, an epoxy resin cured product with excellent flame retardant and low smoke toxicity properties can be obtained. Since the amine curing agent contains a benzoxazine structure, the benzoxazine itself can be cured by heating. During the curing process, the benzoxazine ring undergoes a ring-opening polymerization reaction to form a highly cross-linked network structure, which can further improve the cross-linking density and thermodynamic properties of the epoxy resin cured product. Attached Figure Description

[0048] Figure 1 This is the hydrogen spectrum of the amine curing agent containing benzoxazine prepared in Example 1 of the present invention.

[0049] Figure 2 The image shows the infrared spectrum of the amine curing agent containing benzoxazine prepared in Example 1 of this invention. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited to the following embodiments.

[0051] All raw materials used in this invention are commercially available.

[0052] The performance test experiments of the embodiments and comparative examples of this invention are as follows:

[0053] (1) Glass transition temperature: The test was conducted on a TA Q800 dynamic mechanical property tester in tensile mode. The heating rate was set to 3℃ / min, the temperature scan range was from 50℃ to 350℃, and the test frequency was 1Hz.

[0054] (2) Tensile strength: The tensile strength was measured by a Zwick / Roell Z030 universal testing machine at a test temperature of 25°C and a tensile rate of 2 mm / min. The final performance data was the average of five tests.

[0055] (3) Limiting oxygen index: The test was conducted on a 5801 digital oxygen index analyzer according to the standard ASTM D2863-97. The sample was placed in a glass chimney, and a mixed environment of nitrogen and oxygen was established by the airflow at the bottom of the chimney. The upper part of the sample was ignited, and the oxygen concentration in the flow decreased until the flame stopped burning.

[0056] (4) UL-94 Vertical Burning Test: The test was conducted on a CZF-3 instrument according to the requirements of ASTM D3801. Two 10-second ignition tests were performed, and the time for each sample to extinguish was recorded.

[0057] (5) Cone Calorimetry Test: The heat release of the material was analyzed using a cone calorimeter (CCT), with a heat flux of 35 kW / m². 2 The samples were evaluated according to ISO 5660-1 standard, with each sample group measured three times. Gaseous toxicity (including CO, CO2, etc.) was analyzed according to EN ISO 5659-2.

[0058] (6) Smoke density test: The FTT0064 smoke density chamber was used in accordance with ISO 5659-2 standard.

[0059] Example 1

[0060] (1) Gentamicin (0.01 mol, 2.542 g), diethylenetriamine (0.01 mol, 1.032 g), and paraformaldehyde (0.04 mol, 1.201 g) were placed in a single-necked flask with a magnetic stirrer and dissolved in 50 mL of chloroform at 50 °C. The mixture was heated under reflux at 100 °C for 14 hours. After the reaction was completed, the mixture was allowed to cool at room temperature and then poured into a beaker containing 200 mL of deionized water to obtain a pale yellow precipitate. After filtration, the precipitate was washed 2-3 times with deionized water and dried at 60 °C to obtain benzoxazine-containing amine curing agent 1. The 1H NMR spectrum of the obtained benzoxazine-containing amine curing agent 1 is shown below. Figure 1 As shown, its structural formula is as follows:

[0061]

[0062] The average value of n is 14.81.

[0063] Infrared spectrum of amine curing agent containing benzoxazine 1 is as follows Figure 2 As shown, at 1627cm -1 The absorption peak at 1497 cm⁻¹ is the C=C=O stretching vibration of daidzein. -1 The peak at 1234 cm⁻¹ is the stretching vibration absorption peak of the trisubstituted benzene ring. -1 and 1043cm -1 The absorption peaks at 935 cm⁻¹ represent the symmetric and asymmetric stretching vibrations of the COC on the oxazine ring. -1 The peak at this location is a characteristic peak of the oxazine ring structure. Figure 1 As can be seen from point 2, amine curing agent 1 was successfully prepared.

[0064] (2) The obtained amine curing agent 1 containing benzoxazine and bisphenol A diglycidyl ether were mixed evenly at a ratio of 1:1 between active hydrogen and epoxy group. The mixture was then heated to 80°C in a forced-air oven for mixing. Triethanolamine of 0.05% of the total mass of the mixture was added for pre-curing. Finally, the mixture was cured at 120°C for 2 hours, then at 140°C for 2 hours, then at 160°C for 2 hours, then at 180°C for 2 hours, and finally at 200°C for 2 hours to obtain the epoxy resin cured product.

[0065] Performance testing:

[0066] The glass transition temperature (Tg) is 272℃, the tensile strength is 72MPa, the limiting oxygen index (LOI) is 30.2%, the UL-94 vertical burning test achieved a V-0 rating, and the peak heat release rate (PHRR) is 89MJ / m. 2 The total heat release (THR) is 46 KW / m². 2 The total smoke emission (TSP) was 2.15 m³. 2The CO generation was 0.076 g / g, the CO2 generation was 1.42 g / g, and the maximum smoke density (Ds) was... max The value is 62 MJ / m 3 .

[0067] Example 2

[0068] (1) Gentamicin (0.01 mol, 2.542 g), triethylenetetramine (0.01 mol, 1.462 g), and paraformaldehyde (0.04 mol, 1.201 g) were placed in a single-necked flask with a magnetic stirrer and dissolved in 50 mL of DMF at 60 °C. The mixture was heated under reflux at 120 °C for 10 hours. After the reaction was completed, the mixture was allowed to cool at room temperature and then poured into a beaker containing 200 mL of deionized water to obtain a pale yellow precipitate. After filtration, the precipitate was washed 2-3 times with deionized water and dried at 60 °C to obtain amine curing agent 2 containing benzoxazine, the structural formula of which is as follows:

[0069]

[0070] The average value of n is 12.49.

[0071] (2) The obtained amine curing agent 2 containing benzoxazine and tetramethylbisphenol A diglycidyl ether were mixed evenly at a ratio of 1:1 between active hydrogen and epoxy group. The mixture was then heated to 90°C in a forced-air oven for mixing. 0.1% of the total mass of the mixture was added for pre-curing with dodecylamine. Finally, the mixture was cured at 120°C for 2 hours, then at 140°C for 2 hours, then at 160°C for 2 hours, then at 180°C for 2 hours, and finally at 200°C for 2 hours to obtain the epoxy resin cured product.

[0072] Performance testing:

[0073] The glass transition temperature (Tg) is 275℃, the tensile strength is 82MPa, the limiting oxygen index (LOI) is 31.3%, the UL-94 vertical burning test achieves V-0 rating, and the peak heat release rate (PHRR) is 78MJ / m. 2 The total heat release (THR) is 41 KW / m². 2 The total smoke emission (TSP) was 1.83 m³. 2 The CO generation was 0.069 g / g, the CO2 generation was 1.31 g / g, and the maximum smoke density (Ds) was... max ) is 58 MJ / m 3 .

[0074] Example 3

[0075] (1) Gentamicin (0.01 mol, 2.542 g), tetraethylenepentamine (0.01 mol, 1.893 g), and paraformaldehyde (0.04 mol, 1.201 g) were placed in a single-necked flask with a magnetic stirrer and dissolved in 50 mL of dioxane at 60 °C. The mixture was heated under reflux at 110 °C for 12 hours. After the reaction was completed, the mixture was allowed to cool at room temperature and then poured into a beaker containing 200 mL of deionized water to obtain a yellow precipitate. After filtration, the precipitate was washed 2-3 times with deionized water and dried at 60 °C to obtain amine curing agent 3 containing benzoxazine, the structural formula of which is as follows:

[0076]

[0077] The average value of n is 13.83.

[0078] (2) The obtained amine curing agent 3 containing benzoxazine and 4,4'-dihydroxybenzophenone diglycidyl ether were mixed evenly at a ratio of 2:3 for active hydrogen and epoxy group. The mixture was then heated to 100°C in a forced-air oven for mixing. 0.05% of zinc acetylacetone by mass of the mixture was added for pre-curing. Finally, the mixture was cured at 120°C for 2 hours, then at 140°C for 2 hours, then at 160°C for 2 hours, then at 180°C for 2 hours, and finally at 200°C for 2 hours to obtain the epoxy resin cured product.

[0079] Performance testing:

[0080] The glass transition temperature (Tg) is 265℃, the tensile strength is 81MPa, the limiting oxygen index (LOI) is 32.6%, the UL-94 vertical burning test achieves V-0 rating, and the peak heat release rate (PHRR) is 72MJ / m. 2 The total heat release (THR) is 38 KW / m². 2 The total smoke emission (TSP) was 1.26 m³. 2 The CO generation was 0.063 g / g, the CO2 generation was 1.24 g / g, and the maximum smoke density (Ds) was... max ) is 54 MJ / m 3 .

[0081] Example 4

[0082] (1) Gentamicin (0.01 mol, 2.542 g), pentaethylenehexamine (0.01 mol, 2.324 g), and paraformaldehyde (0.04 mol, 1.201 g) were placed in a single-necked flask with a magnetic stirrer and dissolved in 50 mL of DMF at 60 °C. The mixture was heated under reflux at 130 °C for 15 hours. After the reaction was completed, the mixture was allowed to cool at room temperature and then poured into a beaker containing 200 mL of deionized water to obtain a yellow precipitate. After filtration, the precipitate was washed 2-3 times with deionized water and dried at 60 °C to obtain amine curing agent 4 containing benzoxazine, the structural formula of which is as follows:

[0083]

[0084] The average value of n is 15.46.

[0085] (2) The obtained amine curing agent 4 containing benzoxazine and tetraethyl bisphenol F diglycidyl ether were mixed evenly at a ratio of active hydrogen to epoxy group of 1:2. The mixture was then heated to 90°C in a forced-air oven for mixing. 0.1% of the total mass of the mixture was added for pre-curing. Finally, the mixture was cured at 120°C for 2 hours, then at 140°C for 2 hours, then at 160°C for 2 hours, then at 180°C for 2 hours, and finally at 200°C for 2 hours to obtain the epoxy resin cured product.

[0086] Performance testing:

[0087] The glass transition temperature (Tg) is 274℃, the tensile strength is 90MPa, the limiting oxygen index (LOI) is 30.8%, the UL-94 vertical burning test achieves V-0 rating, and the peak heat release rate (PHRR) is 63MJ / m. 2 The total heat release (THR) is 33 KW / m². 2 The total smoke emission (TSP) was 1.93 m³. 2 The CO generation was 0.072 g / g, the CO2 generation was 1.37 g / g, and the maximum smoke density (Ds) was... max ) is 60MJ / m 3 .

[0088] Comparative Example 1

[0089] The preparation method is the same as in Example 1, except that the amine curing agent 1 containing benzoxazine is replaced with the common curing agent 4,4-diaminodiphenylmethane, and the 4,4-diaminodiphenylmethane and bisphenol A diglycidyl ether are mixed evenly at a ratio of active hydrogen to epoxy group of 1:1.

[0090] Performance testing:

[0091] The glass transition temperature (Tg) is 168℃, the tensile strength is 70MPa, the limiting oxygen index (LOI) is 19.1%, the UL-94 vertical burning test achieves V-2 rating, and the peak heat release rate (PHRR) is 450MJ / m. 2 The total heat release (THR) is 176 KW / m². 2 The total smoke emission (TSP) was 15.6 m³. 2 The CO generation was 0.28 g / g, the CO2 generation was 4.86 g / g, and the maximum smoke density (Ds) was... max The value is 218 MJ / m 3 .

[0092] The above description is merely a preferred embodiment of the present invention and is 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 amine curing agent containing benzoxazine, characterized in that, Includes the following structural units: ; Where R is selected from , , or " " is the connection position; The epoxy resin composition composed of the benzoxazine-containing amine curing agent is cured to obtain a cured epoxy resin product. The limiting oxygen index of the cured epoxy resin product is 30%~35%, and the flame retardant performance reaches V-0 level. The maximum smoke density of the cured epoxy resin product is 50~70 MJ / m³. 3 The CO generation rate is 0.06~0.08 g / g.

2. The method for preparing the amine curing agent containing benzoxazine according to claim 1, characterized in that, Includes the following steps: A benzoxazine-containing amine curing agent was prepared by mixing polyethylene polyamine, organic solvent, daidzein and paraformaldehyde and then reacting them via the Mannich reaction.

3. The method for preparing the amine curing agent containing benzoxazine according to claim 2, characterized in that, The polyethylene polyamine is one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

4. The method for preparing the amine curing agent containing benzoxazine according to claim 2, characterized in that, The molar ratio of the polyethylene polyamine, daidzein, and paraformaldehyde is 1:1~1.3:4~4.

8.

5. The method for preparing the amine curing agent containing benzoxazine according to claim 2, characterized in that, The Mannich reaction temperature is 90~150 ℃, and the reaction time is 8~24 h.

6. An epoxy resin composition comprising an epoxy resin precursor, a benzoxazine-containing amine curing agent as described in claim 1, and a curing accelerator, wherein the ratio of the epoxy equivalent value in the epoxy resin precursor to the active hydrogen equivalent value in the benzoxazine-containing amine curing agent is 10:1 to 10.

7. The epoxy resin composition according to claim 6, characterized in that, The epoxy resin precursor is selected from any of the following structures: ， Where X, Y, and Z are each independently selected from any of the following structures: ， R1, R2, R3, and R4 are each independently selected from hydrogen, C1-C6 alkyl groups, C1-C6 alkoxy groups, phenyl groups, phenoxy groups, or C3-C7 cycloalkyl groups. " is the connection position; The curing accelerator is at least one of tertiary amines, tertiary amine salts, quaternary ammonium salts, imidazole compounds, organophosphorus compounds, metal acetylacetone salts, metal carboxylic acid salts, and boron trifluoride amine complexes.

8. A cured epoxy resin product, characterized in that, The cured product is obtained by gradient curing of the epoxy resin composition according to claim 6 or 7, wherein the gradient curing starts at 120 °C and ends at 200 °C.

9. The application of the epoxy resin cured product according to claim 8 in the fields of composite materials and electronic packaging materials.

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