Toughened epoxy resin for carbon fiber epoxy prepreg and preparation method thereof

Abstract

The invention provides toughened epoxy resin for a carbon fiber epoxy prepreg and a preparation method of the toughened epoxy resin, and relates to the technical field of high polymer material preparation. The preparation method comprises the steps of aminating phenyl polymethylsiloxane, modifying epoxy resin and preparing toughened epoxy resin. And aminating phenyl polymethylsiloxane: mixing phenyl trimethoxy silane, 3-aminopropyltriethoxysilane and a diluent, dropwise adding a catalyst, and adjusting the pH value after a reaction to obtain the amino-containing phenyl polymethylsiloxane. The epoxy resin is modified, wherein phenyl polymethylsiloxane containing amino groups and polyhedral oligomeric silsesquioxane are used as modifiers. And preparing toughened epoxy resin: mixing the modified epoxy resin, solid epoxy resin, a diluent, a curing agent and a flame retardant. The toughened epoxy resin prepared by the invention maintains a high glass transition temperature while toughening, and optimizes the interlaminar shear strength and flexural modulus of the carbon fiber epoxy prepreg.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer material preparation, and particularly relates to a toughened epoxy resin for carbon fiber epoxy prepreg and a preparation method thereof. BACKGROUND

[0002] Carbon fiber epoxy prepreg exhibits excellent specific strength and specific stiffness characteristics, and has fatigue resistance far exceeding that of conventional materials, can withstand a large amount of cyclic stress without damage, and is widely used in various fields such as aerospace, rail transportation and construction industry. However, the cured traditional epoxy resin has high brittleness, which leads to insufficient interlaminar toughness of the composite material, and easy interfacial debonding and crack propagation under dynamic load. The existing toughening technology mainly realizes through the addition of rubber elastomer or thermoplastic resin, but often leads to a significant decrease in glass transition temperature (Tg) of the system and damage to thermal stability. In actual application, especially for structures that may bear dynamic load or accidental impact, such as some parts in aerospace, collision parts of automobiles, etc., the low toughness of the epoxy resin limits the overall performance and safety of the material.

[0003] The technology disclosed in Publication No. CN117069987B introduces nano-aluminum oxide fiber to reinforce the system, and through the synergistic mechanism of the nano-aluminum oxide fiber and the mixed resin matrix, the thermal conductivity and mechanical strength of the prepreg material are synergistically optimized, which is particularly suitable for fields with strict requirements on thermal management efficiency and load capacity; the technology optimizes the thermal conductivity and mechanical strength of the carbon fiber epoxy prepreg, but does not improve the toughness of the material.

[0004] The technology disclosed in Publication No. CN118421244B is based on the innovative molecular architecture design concept, adopts the topology structure regulation technology of branched epoxy resin, and combines the solvent-free green forming process, so that the glass transition temperature of the epoxy adhesive is broken through to Tg>280℃, meeting the needs of extreme high temperature and flame retardant scenes; the technology not only improves the glass transition temperature of the carbon fiber epoxy prepreg, but also is environmentally friendly, but does not improve the toughness of the material.

[0005] The epoxy resin for carbon fiber epoxy prepreg prepared by the existing technology has the following technical defects: poor impact toughness and mechanical properties, and low glass transition temperature. SUMMARY

[0006] In combination with the deficiencies of the existing technology, the present application aims to provide a toughened epoxy resin for carbon fiber epoxy prepreg and a preparation method thereof, and to achieve the following application purposes: to produce an epoxy resin with good impact toughness and mechanical properties and high glass transition temperature.

[0007] To achieve the above application purposes, the present application provides the following technical solutions: A method for preparing a toughened epoxy resin for carbon fiber epoxy prepreg comprises the following steps: Step 1, aminophenyl polymethylsiloxane phenyl trimethoxysilane, 3-amino propyl triethoxysilane and diluent are added into a reaction kettle, the temperature is raised to 40-60℃, stirring is carried out at a speed of 200-300 rpm for 10-15 min; the temperature is raised to 60-80℃, stirring is carried out at a speed of 300-500 rpm, a catalyst is added dropwise, the dropwise adding time is 1-2 h, after the dropwise adding is completed, the reaction is continued for 2-4 h; the pH value is adjusted to 6-7, and the amino-containing phenyl polymethylsiloxane is obtained by distillation under reduced pressure.

[0008] the diluent is propylene glycol methyl ether; the catalyst is glacial acetic acid; the pH value is adjusted by using triethylamine as the pH value adjusting agent; the mass ratio of the phenyl trimethoxysilane, 3-amino propyl triethoxysilane, diluent and catalyst is 10: (10-12): (10-20): (0.1-0.3).

[0009] Step 2, modified epoxy resin the amino-containing phenyl polymethylsiloxane and cage polysilsesquioxane are added into a reaction kettle, nitrogen is introduced, the temperature is raised to 40-60℃, stirring is carried out at a speed of 300-500 rpm for 20-30 min; a coupling agent is added, and the reaction is carried out for 1-3 h; the temperature is raised to 60-80℃, liquid epoxy resin and an accelerator are added, and the reaction is continued for 2-3 h, to obtain a modified epoxy resin.

[0010] the cage polysilsesquioxane is amino propyl heptyl cage polysilsesquioxane; the coupling agent is γ-glycidyl ether propyl trimethoxysilane; the liquid epoxy resin is bisphenol A type E51 epoxy resin; the accelerator is 2,4,6-tris (dimethylaminomethyl) phenol; the mass ratio of the amino-containing phenyl polymethylsiloxane, cage polysilsesquioxane, coupling agent, liquid epoxy resin and accelerator is (5-15): (10-20): (4-7): 100: (0.5-1.5).

[0011] Step 3, preparation of toughened epoxy resin the modified epoxy resin, solid epoxy resin, diluent, curing agent and flame retardant are added into a stirring machine, the vacuum degree is controlled to be 0.085-0.095 MPa, the temperature is raised to 65-80℃, stirring is carried out at a speed of 500-800 rpm for 30-50 min, to obtain a toughened epoxy resin.

[0012] The solid epoxy resin is bisphenol A type E-20 epoxy resin; The diluent is propylene glycol methyl ether; The curing agent is phthalic anhydride; The flame retardant is a combination of cyanuric acid melamine and aluminum hydroxide, and the mass ratio of cyanuric acid melamine to aluminum hydroxide is (7-15):(8-13).

[0013] The feeding mass ratio of the modified epoxy resin, the solid epoxy resin, the diluent, the curing agent and the flame retardant is 100:(20-30):(10-15):(30-40):(15-25).

[0014] Compared with the prior art, the toughened epoxy resin prepared by the present application for carbon fiber epoxy prepreg has the following beneficial effects: 1. The epoxy resin prepared by the present application has excellent impact toughness and mechanical properties, the tensile strength reaches 80 MPa, the bending strength is not less than 130 MPa, and the impact toughness is greater than 20.0 kJ / m²; 2. The epoxy resin prepared by the present application maintains the glass transition temperature (Tg) at 175-182℃ while being toughened; 3. The epoxy resin prepared by the present application optimizes the interlaminar shear strength and bending modulus of the carbon fiber epoxy prepreg, and the interlaminar shear strength of the carbon fiber epoxy prepreg produced by using the epoxy resin prepared by the present application as raw material is greater than 65.0 MPa, and the bending modulus is 24.5-28.0 GPa. DETAILED DESCRIPTION

[0015] The following preferred examples of the present application are only used to explain the present application, and are not used to limit the present application.

[0016] Example 1, a preparation method of a toughened epoxy resin for carbon fiber epoxy prepreg Step 1, aminophenyl polymethylsiloxane Phenyltrimethoxysilane, 3-aminopropyltriethoxysilane and propylene glycol methyl ether were added to a reaction kettle, nitrogen was introduced, the temperature was raised to 40℃, and stirring was carried out at a speed of 200 rpm for 15 min; the temperature was raised to 80℃, and stirring was carried out at a speed of 400 rpm, and ice acetic acid was added by peristaltic pump, the dropping time was 1 h, and after the dropping was completed, the reaction was continued for 3 h; cooled to below 50℃, the pH value was adjusted to 7 with 0.5% triethylamine aqueous solution, and then distilled under reduced pressure, washed and dried to obtain aminophenyl polymethylsiloxane.

[0017] The feeding mass ratio of the phenyl trimethoxysilane, 3-aminopropyl triethoxysilane, propylene glycol methyl ether and glacial acetic acid is 10:10:15:0.2.

[0018] Step 2, modifying the epoxy resin The amino-containing phenyl polymethylsiloxane and aminopropyl heptyl cage polysilsesquioxane are added to a reaction kettle, nitrogen is introduced, and the temperature is raised to 40℃. Stirring is carried out at a speed of 400 rpm for 20 min; γ-glycidyl ether propyl trimethoxysilane is added, and the reaction is carried out for 2 h; the temperature is raised to 60℃, and bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol are added, and the reaction is continued for 3 h to obtain a modified epoxy resin.

[0019] The feeding mass ratio of the amino-containing phenyl polymethylsiloxane, aminopropyl heptyl cage polysilsesquioxane, γ-glycidyl ether propyl trimethoxysilane, bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol is 10:15:4:100:0.8.

[0020] Step 3, preparing a toughened epoxy resin The modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant are added to a blender, the vacuum degree is controlled to be 0.085-0.095 MPa, the temperature is raised to 70℃, and stirring is carried out at a speed of 600 rpm for 30 min; a toughened epoxy resin is obtained. The flame retardant is a combination of melamine cyanurate and aluminum hydroxide, and the mass ratio of melamine cyanurate to aluminum hydroxide is 7:13.

[0021] The feeding mass ratio of the modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant is 100:20:10:30:20.

[0022] Example 2, a method for preparing a toughened epoxy resin for carbon fiber epoxy prepreg Step 1, aminating phenyl polymethylsiloxane Phenyl trimethoxysilane, 3-aminopropyl triethoxysilane and propylene glycol methyl ether are added to a reaction kettle, nitrogen is introduced, and the temperature is raised to 60℃. Stirring is carried out at a speed of 250 rpm for 15 min; the temperature is raised to 70℃, and stirring is carried out at a speed of 400 rpm. Glacial acetic acid is added dropwise using a peristaltic pump, the dropwise addition lasts for 2 h, and after the dropwise addition is completed, the reaction is continued for 2 h; the temperature is cooled to below 50℃, a 0.5% mass fraction triethylamine aqueous solution is used to adjust the pH value to 6, and a toughened epoxy resin is obtained by vacuum distillation, washing and drying.

[0023] The feeding mass ratio of the phenyl trimethoxysilane, 3-aminopropyl triethoxysilane, propylene glycol methyl ether and glacial acetic acid is 10:11:10:0.1.

[0024] Step 2, modifying the epoxy resin The amino-containing phenyl polymethylsiloxane and aminopropyl heptyl cage polysilsesquioxane were added to the reaction kettle, nitrogen was introduced, and the temperature was raised to 60°C. Stirring was carried out at a speed of 500 rpm for 30 min; γ-glycidyl ether propyl trimethoxysilane was added, and the reaction was carried out for 2 h; the temperature was raised to 70°C, and bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol were added, and the reaction was continued for 3 h to obtain a modified epoxy resin.

[0025] The feeding mass ratio of the amino-containing phenyl polymethylsiloxane, aminopropyl heptyl cage polysilsesquioxane, γ-glycidyl ether propyl trimethoxysilane, bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol is 5:20:6:100:1.

[0026] Step 3, preparing a toughened epoxy resin The modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant were added to the blender, the vacuum degree was controlled to be 0.085-0.095 MPa, the temperature was raised to 65°C, and stirring was carried out at a speed of 500 rpm for 40 min; a toughened epoxy resin was obtained. The flame retardant is a combination of melamine cyanurate and aluminum hydroxide, and the mass ratio of melamine cyanurate to aluminum hydroxide is 3:2.

[0027] The feeding mass ratio of the modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant is 100:25:15:30:25.

[0028] Example 3, a method for preparing a toughened epoxy resin for carbon fiber epoxy prepreg Step 1, aminating phenyl polymethylsiloxane Phenyl trimethoxysilane, 3-aminopropyl triethoxysilane and propylene glycol methyl ether were added to the reaction kettle, nitrogen was introduced, the temperature was raised to 50°C, and stirring was carried out at a speed of 300 rpm for 10 min; the temperature was raised to 75°C, and stirring was carried out at a speed of 300 rpm. Glacial acetic acid was added dropwise using a peristaltic pump, the dropwise addition lasted for 1.5 h, and after the dropwise addition was completed, the reaction was continued for 4 h; cooled to below 50°C, the pH value was adjusted to 6 using a 1.0% mass fraction triethylamine aqueous solution, and a toughened epoxy resin was obtained by vacuum distillation, washing and drying.

[0029] The feeding mass ratio of the phenyl trimethoxysilane, 3-aminopropyl triethoxysilane, propylene glycol methyl ether and glacial acetic acid is 10:12:20:0.3.

[0030] Step 2, modifying the epoxy resin The amino-containing phenyl polymethylsiloxane and aminopropyl heptyl cage polysilsesquioxane are added to a reaction kettle, nitrogen is introduced, and the temperature is raised to 50℃. Stirring is carried out at a speed of 300 rpm for 25 min; γ-glycidyl ether propyl trimethoxysilane is added, and the reaction is carried out for 3 h; the temperature is raised to 60℃, and bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol are added, and the reaction is continued for 2 h to obtain a modified epoxy resin.

[0031] The feeding mass ratio of the amino-containing phenyl polymethylsiloxane, aminopropyl heptyl cage polysilsesquioxane, γ-glycidyl ether propyl trimethoxysilane, bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol is 15:10:5:100:0.5.

[0032] Step 3, preparing a toughened epoxy resin The modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant are added to a blender, the vacuum degree is controlled to be 0.085-0.095 MPa, the temperature is raised to 80℃, and stirring is carried out at a speed of 700 rpm for 50 min; a toughened epoxy resin is obtained. The flame retardant is a combination of melamine cyanurate and aluminum hydroxide, and the mass ratio of melamine cyanurate to aluminum hydroxide is 7:8.

[0033] The feeding mass ratio of the modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant is 100:30:10:40:15.

[0034] Example 4, a method for preparing a toughened epoxy resin for carbon fiber epoxy prepreg Step 1, aminating phenyl polymethylsiloxane Phenyl trimethoxysilane, 3-aminopropyl triethoxysilane and propylene glycol methyl ether are added to a reaction kettle, nitrogen is introduced, and the temperature is raised to 45℃. Stirring is carried out at a speed of 250 rpm for 15 min; the temperature is raised to 60℃, and stirring is carried out at a speed of 500 rpm. Glacial acetic acid is added dropwise using a peristaltic pump, the dropwise addition lasts for 2 h, and after the dropwise addition is completed, the reaction is continued for 2 h; the temperature is cooled to below 50℃, a 1.0% mass fraction triethylamine aqueous solution is used to adjust the pH value to 7, and a toughened epoxy resin is obtained by vacuum distillation, washing and drying.

[0035] The feeding mass ratio of the phenyl trimethoxysilane, 3-aminopropyl triethoxysilane, propylene glycol methyl ether and glacial acetic acid is 10:11:15:0.15.

[0036] Step 2, modifying the epoxy resin The amino-containing phenyl polymethylsiloxane and aminopropyl heptyl cage polysilsesquioxane are added into a reaction kettle, nitrogen is introduced, the temperature is raised to 60°C, and stirring is carried out at a speed of 400 rpm for 30 min; γ-glycidoxypropyl trimethoxysilane is added, and the reaction is carried out for 1 h; the temperature is raised to 80°C, bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol are added, and the reaction is continued for 2 h to obtain a modified epoxy resin.

[0037] The feeding mass ratio of the amino-containing phenyl polymethylsiloxane, aminopropyl heptyl cage polysilsesquioxane, γ-glycidoxypropyl trimethoxysilane, bisphenol A type E51 epoxy resin and 2,4,6-tris(dimethylaminomethyl) phenol is 8:15:7:100:1.5.

[0038] Step 3, preparing a toughened epoxy resin The modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant are added into a blender, the vacuum degree is controlled to be 0.085-0.095 MPa, the temperature is raised to 65°C, and stirring is carried out at a speed of 800 rpm for 30 min; a toughened epoxy resin is obtained. The flame retardant is a combination of melamine cyanurate and aluminum hydroxide, and the mass ratio of melamine cyanurate to aluminum hydroxide is 12:13.

[0039] The feeding mass ratio of the modified epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride and flame retardant is 100:25:15:35:25.

[0040] Comparative Example 1, a method for preparing an epoxy resin for carbon fiber epoxy prepreg The bisphenol A type E51 epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride, melamine cyanurate and aluminum hydroxide are added into a blender, the vacuum degree is controlled to be 0.085-0.095 MPa, the temperature is raised to 65°C, and stirring is carried out at a speed of 800 rpm for 30 min; an epoxy resin for carbon fiber epoxy prepreg is obtained.

[0041] The feeding mass ratio of the bisphenol A type E51 epoxy resin, bisphenol A type E-20 epoxy resin, propylene glycol methyl ether, phthalic anhydride, melamine cyanurate and aluminum hydroxide is 100:30:15:40:12:15.

[0042] Example 5 Preparation method of carbon fiber epoxy prepreg Step 1, film forming The epoxy resin was coated on release paper with a coating machine, the coating thickness was 0.3 mm, and pre-baking was performed at a temperature of 100℃ for 5 min to obtain a film.

[0043] Step 2, composite carbon fiber The film and carbon fiber were combined by a hot press composite machine, the temperature was set to 80℃, the pressure was 1.0 MPa, and hot pressing was performed for 5 min; winding was performed to obtain a carbon fiber epoxy prepreg.

[0044] Performance test: (1) The epoxy resins prepared in Examples 1-4 and Comparative Example 1 were respectively tested for performance.

[0045] Test method: The epoxy resin was cured, and after curing, the tensile strength, bending strength and impact toughness were tested according to "GB / T 2567-2021 Resin Casting Performance Test Method", and the glass transition temperature was tested according to "GB / T 19466.2-2004 Plastics Differential Scanning Calorimetry (DSC) Part 2: Determination of Glass Transition Temperature"; the test results are shown in Table 1.

[0046] The curing method of the epoxy resin is as follows: the epoxy resin is placed in a hot press tank, heated to 120℃ at a heating rate of 2℃ / min, the pressure is kept at 0.6 MPa, and the pressure is kept for 1.5 h; then heated to 180℃ at a heating rate of 1.5℃ / min, the pressure is increased to 1.2 MPa, and the second pressure is kept for 2 h; naturally cooled to below 60℃, and demolded.

[0047] Table 1 Performance test results of epoxy resin Item Tensile strength (MPa) Flexural strength (MPa) Impact toughness (kJ / m²) Glass transition temperature (°C) Example 1 85 135 25.6 178 Example 2 88 142 27.3 180 Example 3 82 130 23.8 175 Example 4 92 150 30.1 182 Comparative Example 1 70 115 15.4 165 As can be seen from Table 1, the tensile strength of Examples 1-4 is 82-92 MPa, the bending strength is 130-150 MPa, the impact toughness is 23.8-30.1 kJ / m², and the glass transition temperature is 175-182℃; compared with the epoxy resin prepared in Comparative Example 1, the performance is obviously improved.

[0048] (II) The toughened epoxy resins of Examples 1-4 were used to prepare carbon fiber epoxy prepreg according to the method of Example 5, and the carbon fiber epoxy prepreg was cured. After curing, the interlaminar shear strength was tested according to GB / T 1450.1-2005, the flexural modulus was tested according to GB / T 3356-2014, and the oxygen index was tested according to GB / T 8924-2005. The test results are shown in Table 2.

[0049] The curing method of the carbon fiber epoxy prepreg was as follows: the prepreg was added to a hot press tank, heated to 100℃ at a heating rate of 2℃ / min, pressurized to 0.6 MPa, and held for 2 h. Then, the temperature was raised to 150℃ at a heating rate of 2℃ / min, the pressure was raised to 1.0 MPa, and the second holding was performed for 1 h. The mold was demolded after natural cooling to below 60℃.

[0050] Table 2 Performance test results of carbon fiber epoxy prepreg Item Interlaminar shear strength (MPa) Flexural modulus (GPa) Oxygen index (%) Example 1 68.5 25.2 30.5 Example 2 70.2 26.8 31.0 Example 3 65.8 24.5 29.8 Example 4 73.2 28.0 32.0 Comparative Example 1 54.7 20.3 27.5 According to Table 2, the carbon fiber epoxy prepreg prepared using the epoxy resins of Examples 1-4 as raw materials had an interlaminar shear strength of 65.8-73.2 MPa, a flexural modulus of 24.5-28.0 GPa, and an oxygen index of 29.8-32.0%, and the related properties were better than those of the carbon fiber epoxy prepreg prepared using the epoxy resin of Comparative Example 1 as raw material.

[0051] It should be noted that the above examples are only more representative embodiments of the present application, and do not limit the scope of patent protection. Any person skilled in the art who is based on the technical scheme of the present application, within the framework of the claims of the present application, adjusts or equivalently replaces the technical scheme, should be considered to fall within the scope of patent protection of the present application.

Claims

1. A process for the preparation of a toughened epoxy resin for carbon fiber epoxy prepreg characterized by: The preparation method comprises the steps of aminophenyl polysiloxane, modified epoxy resin and toughened epoxy resin preparation; The aminophenyl polysiloxane is prepared by mixing phenyl trimethoxysilane, 3-aminopropyl triethoxysilane and a diluent, heating to 40-60 DEG C and stirring for 10-15 min; heating to 60-80 DEG C, adding a catalyst dropwise, dropwise adding for 1-2 h, and continuing to react for 2-4 h after dropwise adding is completed; The modified epoxy resin is prepared by using amino-containing phenyl polysiloxane and cage polysilsesquioxane as modifiers; The toughened epoxy resin is prepared by using modified epoxy resin, solid epoxy resin, diluent, curing agent and flame retardant as raw materials, and the reaction temperature is 65-80 DEG C and the reaction time is 30-50 min.

2. The preparation method of the toughened epoxy resin for carbon fiber epoxy prepreg according to claim 1, characterized in that: The modified epoxy resin is prepared by adding amino-containing phenyl polysiloxane and cage polysilsesquioxane into a reaction kettle, heating to 40-60 DEG C, stirring for 20-30 min, adding a coupling agent and reacting for 1-3 h, heating to 60-80 DEG C, adding liquid epoxy resin and an accelerator and continuing to react for 2-3 h.

3. The method of claim 1, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The aminophenyl polysiloxane is prepared by mixing phenyl trimethoxysilane, 3-aminopropyl triethoxysilane, diluent and catalyst, and the mass ratio of the raw materials is 10:(10-12):(10-20):(0.1-0.3).

4. The method of claim 1, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The modified epoxy resin is prepared by using amino-containing phenyl polysiloxane, cage polysilsesquioxane, coupling agent, liquid epoxy resin and accelerator as raw materials, and the mass ratio of the raw materials is (5-15):(10-20):(4-7):100:(0.5-1.5).

5. The method of claim 1, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The toughened epoxy resin is prepared by using modified epoxy resin, solid epoxy resin, diluent, curing agent and flame retardant as raw materials, and the mass ratio of the raw materials is 100:(20-30):(10-15):(30-40):(15-25).

6. The method of claim 1, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The pH value regulator used is triethylamine.

7. The method of claim 1, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The diluent is propylene glycol methyl ether; the catalyst is glacial acetic acid; the cage polysilsesquioxane is amino propyl heptyl cage polysilsesquioxane; the coupling agent is gamma-glycidyl ether oxygen propyl trimethoxysilane; and the accelerator is 2,4,6-tris(dimethylaminomethyl) phenol.

8. The method of claim 1, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The curing agent is phthalic anhydride; and the flame retardant is a combination of cyanuric acid melamine and aluminum hydroxide.

9. The method of claim 3, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The liquid epoxy resin is bisphenol A type E51 epoxy resin.

10. The method of claim 4, wherein the toughened epoxy resin for carbon fiber epoxy prepreg is characterized by: The solid epoxy resin is bisphenol A type E-20 epoxy resin.