Epoxy resin composition, preparation method and application

Abstract

The invention discloses an epoxy resin composition, a preparation method and application, and relates to epoxy resin, a preparation method and application. The invention aims to solve the problem of unreasonable processing period of the existing epoxy resin composition for preparing the prepreg. The epoxy resin composition consists of a component A and a component B, the component A consists of liquid epoxy resin I and solid epoxy resin; the component B consists of liquid epoxy resin II, a curing agent and an accelerant; the preparation method comprises the following steps: heating to melt the solid epoxy resin, adding the liquid epoxy resin I, and uniformly stirring to obtain the component A; mixing liquid epoxy resin II, a curing agent and an accelerant, grinding, heating and uniformly mixing to obtain a component B; and uniformly stirring and mixing the component A and the component B at 55-85 DEG C. The resin composition provided by the invention has good manufacturability and laying property, and a prepreg composite material prepared from the resin composition shows excellent mechanical properties and heat resistance, is suitable for the engineering fields of automobiles and the like, and meets the requirements of light weight and high strength.

Description

Technical Field

[0001] The invention relates to an epoxy resin, a preparation method and application. Background Art

[0002] In the field of engineering, whether it is a large space shuttle or a tiny mechanical part, lightweighting is a common challenge. As the key load-bearing part of the car, the car body directly affects the safety space of the occupants. At the same time, the introduction of automobile energy-saving and emission reduction regulations has further strengthened the importance of lightweight design of the car body. The use of lightweight and high-strength materials has become one of the important strategies for lightweighting the car body. As a representative of lightweight materials, carbon fiber composite materials have become a strong candidate material due to their excellent properties such as low density, high specific strength, high specific modulus, fatigue resistance, corrosion resistance, excellent thermal stability and chemical stability.

[0003] Prepreg is a material that has a certain storage period at room temperature by continuously impregnating reinforcing fibers or fiber fabrics under accurate control of the resin matrix. The pre-impregnation of resin greatly reduces the processing steps in the production process of the final product. It has a high degree of automation and can form complex-shaped components in one go, and has broad application prospects. Carbon fiber has gradually replaced traditional glass fiber as the main prepreg reinforcement due to its excellent mechanical properties and stability.

[0004] Hot-melt prepregs require that the resin system has a low viscosity when melted at high temperature and requires a sufficiently long processing period to completely wet the fibers; and during storage or transportation at room temperature, the resin system in the hot-melt prepreg needs to have a certain viscosity without causing glue flow.

[0005] Therefore, how to create a new epoxy resin composition, prepreg and preparation method thereof, extend the processing period of the epoxy resin matrix, meet the requirements of continuous process production, and meet the requirements that the product has good mechanical properties after the resin is cured, has become a key improvement goal that needs to be urgently solved in the current industry.

[0006] In the prior art, epoxy resin compositions often have high viscosity when melted at high temperature and the viscosity increases too quickly, resulting in a short processing period, which is not conducive to complete impregnation of fibers, resulting in poor impregnation phenomena such as pitting, dry yarn and twisting, affecting the overall performance of the prepreg. In addition, there are also problems such as low viscosity at room temperature leading to glue flow and poor dimensional stability. The prepared prepreg has obvious bending and deformation after the release paper is peeled off, which is not conducive to storage and transportation, and affects the mechanical properties of the final cured product. Summary of the invention

[0007] In order to solve the problem of unreasonable processing time of the existing epoxy resin composition for preparing prepreg, the present invention provides an epoxy resin composition, a preparation method and application.

[0008] The epoxy resin composition of the present invention is composed of component A and component B; the mass ratio of component A to component B is 100:(20-40);

[0009] The component A is composed of liquid epoxy resin I and solid epoxy resin; the liquid epoxy resin I is 20 to 50 parts and the solid epoxy resin is 40 to 80 parts in the component A;

[0010] The B component is composed of liquid epoxy resin II, curing agent and accelerator; the B component contains 60-90 parts of liquid epoxy resin II, 2-10 parts of curing agent and 1-5 parts of accelerator;

[0011] The softening point of the solid epoxy resin is 55-95°C; the softening points of the liquid epoxy resin I and the liquid epoxy resin II are lower than 25°C.

[0012] The preparation method of the epoxy resin composition is carried out according to the following steps:

[0013] 1. Preparation of component A: heat to melt the solid epoxy resin, then add the liquid epoxy resin I, stir and mix evenly to obtain component A;

[0014] 2. Preparation of component B: Mix and grind the liquid epoxy resin II, the curing agent and the accelerator, heat to 55-85°C, stir and mix evenly to obtain component B;

[0015] 3. Preparation of epoxy resin composition: Component A prepared in step 1 and component B prepared in step 2 are stirred and mixed at 55-85° C., and then cooled to obtain an epoxy resin composition.

[0016] The method for preparing epoxy resin prepreg using the above epoxy resin composition is carried out according to the following steps:

[0017] 1. Weigh the epoxy resin composition and carbon fiber;

[0018] 2. coating the epoxy resin composition with a film coating machine to obtain an epoxy resin film; the coating temperature of the film coating machine is 70 to 90° C., and the coating speed is 4 to 12 m / min;

[0019] 3. Laying the carbon fiber between two layers of epoxy resin films and performing hot pressing compounding to obtain carbon fiber prepreg.

[0020] The principles and beneficial effects of the present invention are:

[0021] The epoxy resin composition of the present invention is composed of component A and component B, wherein component A is composed of liquid epoxy resin I and solid epoxy resin, and component B is composed of epoxy resin II, curing agent and accelerator. The preparation of component A is a high softening point solid epoxy resin melt mixing process, and the preparation of component B is an auxiliary agent grinding process. The two-component design separates the preparation process, avoiding the problem of high viscosity of the glue and uneven components caused by adding solid epoxy resin and auxiliary agent at the same time. By selecting the type of resin, adjusting the resin ratio and the amount of auxiliary agent, the curing speed of the resin composition is adjusted, so that the coating process has a longer processing period, the quality of the obtained glue film is uniform, and it is suitable for the production of large quantities of prepregs.

[0022] In the present invention, the addition of high-softening-point solid epoxy resin makes the resin composition have a higher viscosity at room temperature, and the prepared prepreg does not flow during storage or transportation at room temperature, and the size and shape do not change significantly after peeling off the release paper, which is beneficial to subsequent paving processing and curing, and effectively improves the stability of storage and transportation of the prepreg and the quality of the final cured product.

[0023] The present invention selects solid epoxy resin with high thermal stability and multifunctional liquid epoxy resin as preparation raw materials. The solid epoxy resin used has excellent heat resistance, can maintain stable chemical structure and physical properties at high temperature, and has less loss of mechanical properties. The multifunctional liquid epoxy resin forms a high-density cross-linked network through intermolecular cross-linking reaction. The selected curing agent and accelerator promote the intermolecular cross-linking reaction, form a more compact and stable chemical structure, and improve the heat resistance of the cured product of the resin composition.

[0024] When the resin composition film of the present invention is composited with fibers, the viscosity of the resin adhesive is low at the selected composite temperature, and the fibers can be completely impregnated, thereby avoiding the problems of pitting and dry yarn in the prepreg. The resin and fibers have good wettability and high interface bonding strength, so that the final cured product has excellent mechanical strength and heat resistance.

[0025] The epoxy resin composition of the present invention has good processability and coating properties, and the cured product of the epoxy resin composition has excellent heat resistance and mechanical strength properties, and can meet the requirements of composite materials used in the automotive field and other fields for mechanics, heat resistance, lightness, and high strength. In addition, the prepreg and composite material raw materials provided by the present invention are simple and easy to obtain, low in cost, and suitable for rapid and large-scale production. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any reasonable combination of the specific implementation modes.

[0027] Specific implementation method 1: The epoxy resin composition of this implementation method is composed of component A and component B; the mass ratio of component A to component B is 100:(20-40);

[0028] The component A is composed of liquid epoxy resin I and solid epoxy resin; the liquid epoxy resin I is 20 to 50 parts and the solid epoxy resin is 40 to 80 parts in the component A;

[0029] The B component is composed of liquid epoxy resin II, curing agent and accelerator; the B component contains 60-90 parts of liquid epoxy resin II, 2-10 parts of curing agent and 1-5 parts of accelerator;

[0030] The softening point of the solid epoxy resin is 55-95°C; the softening points of the liquid epoxy resin I and the liquid epoxy resin II are lower than 25°C.

[0031] The epoxy resin composition of this embodiment is composed of component A and component B, wherein component A is composed of liquid epoxy resin I and solid epoxy resin, and component B is composed of epoxy resin II, curing agent and accelerator. The preparation of component A is a high softening point solid epoxy resin melt mixing process, and the preparation process of component B is an auxiliary agent grinding process. The two-component design separates the preparation process to avoid the problem of high viscosity of the glue and uneven components caused by the simultaneous addition of solid epoxy resin and auxiliary agent. By selecting the type of resin, adjusting the resin ratio and the amount of auxiliary agent, the curing speed of the resin composition is adjusted, so that the coating process has a longer processing period, and the obtained adhesive film has uniform quality, which is suitable for the production of large quantities of prepregs.

[0032] In this embodiment, the addition of high softening point solid epoxy resin makes the resin composition have a higher viscosity at room temperature, and the prepared prepreg does not flow during storage or transportation at room temperature, and the size and shape do not change significantly after peeling off the release paper, which is beneficial to subsequent paving processing and curing, and effectively improves the stability of storage and transportation of the prepreg and the quality of the final cured product.

[0033] This embodiment uses a solid epoxy resin with high thermal stability and a multifunctional liquid epoxy resin as preparation raw materials. The solid epoxy resin used has excellent heat resistance, can maintain a stable chemical structure and physical properties at high temperatures, and has a small loss in mechanical properties; the multifunctional liquid epoxy resin forms a high-density cross-linked network through intermolecular cross-linking reactions; the selected curing agent and accelerator promote the intermolecular cross-linking reaction, forming a more compact and stable chemical structure, thereby improving the heat resistance of the cured product of the resin composition.

[0034] When the resin composition film of this embodiment is composited with fibers, the viscosity of the resin adhesive is low at the selected composite temperature, and the fibers can be completely impregnated, thereby avoiding problems such as pitting and dry yarn in the prepreg. The resin and fibers have good wettability and high interface bonding strength, so that the final cured product has excellent mechanical strength and heat resistance properties.

[0035] The epoxy resin composition of this embodiment has good processability and coating properties, and the cured product of the epoxy resin composition has excellent heat resistance and mechanical strength properties, which can meet the requirements of composite materials used in the automotive field and other fields for mechanics, heat resistance, lightness, and high strength. In addition, the prepreg and composite material raw materials provided by this embodiment are simple and easy to obtain, low in cost, and suitable for rapid and large-scale production.

[0036] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that the curing agent is a dicyandiamide curing agent.

[0037] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that the liquid epoxy resin I is a liquid bisphenol A epoxy resin, a liquid alicyclic epoxy resin, a liquid aliphatic epoxy resin, a liquid bisphenol F epoxy resin, a liquid phenolic epoxy resin or a liquid glycidylamine epoxy resin.

[0038] Specific embodiment 4: This embodiment is different from any one of specific embodiments 1 to 3 in that the liquid epoxy resin II is a liquid bisphenol A epoxy resin, a liquid alicyclic epoxy resin, a liquid aliphatic epoxy resin, a liquid bisphenol F epoxy resin, a liquid phenolic epoxy resin or a liquid glycidylamine epoxy resin.

[0039] Specific implementation mode 5: This implementation mode is different from any one of specific implementation modes 1 to 4 in that: the accelerator is organic urea.

[0040] Specific embodiment 6: The preparation method of the epoxy resin composition of this embodiment is carried out according to the following steps:

[0041] 1. Preparation of component A: heat to melt the solid epoxy resin, then add the liquid epoxy resin I, stir and mix evenly to obtain component A;

[0042] 2. Preparation of component B: Mix and grind the liquid epoxy resin II, the curing agent and the accelerator, heat to 55-85°C, stir and mix evenly to obtain component B;

[0043] 3. Preparation of epoxy resin composition: Component A prepared in step 1 and component B prepared in step 2 are stirred and mixed at 55-85° C., and then cooled to obtain an epoxy resin composition.

[0044] The epoxy resin composition of this embodiment is composed of component A and component B, wherein component A is composed of liquid epoxy resin I and solid epoxy resin, and component B is composed of epoxy resin II, curing agent and accelerator. The preparation of component A is a high softening point solid epoxy resin melt mixing process, and the preparation process of component B is an auxiliary agent grinding process. The two-component design separates the preparation process to avoid the problem of high viscosity of the glue and uneven components caused by the simultaneous addition of solid epoxy resin and auxiliary agent. By selecting the type of resin, adjusting the resin ratio and the amount of auxiliary agent, the curing speed of the resin composition is adjusted, so that the coating process has a longer processing period, and the obtained adhesive film has uniform quality, which is suitable for the production of large quantities of prepregs.

[0045] In this embodiment, the addition of high softening point solid epoxy resin makes the resin composition have a higher viscosity at room temperature, and the prepared prepreg does not flow during storage or transportation at room temperature, and the size and shape do not change significantly after peeling off the release paper, which is beneficial to subsequent paving processing and curing, and effectively improves the stability of storage and transportation of the prepreg and the quality of the final cured product.

[0046] This embodiment uses a solid epoxy resin with high thermal stability and a multifunctional liquid epoxy resin as preparation raw materials. The solid epoxy resin used has excellent heat resistance, can maintain a stable chemical structure and physical properties at high temperatures, and has a small loss in mechanical properties; the multifunctional liquid epoxy resin forms a high-density cross-linked network through intermolecular cross-linking reactions; the selected curing agent and accelerator promote the intermolecular cross-linking reaction, forming a more compact and stable chemical structure, thereby improving the heat resistance of the cured product of the resin composition.

[0047] When the resin composition film of this embodiment is composited with fibers, the viscosity of the resin adhesive is low at the selected composite temperature, and the fibers can be completely impregnated, thereby avoiding problems such as pitting and dry yarn in the prepreg. The resin and fibers have good wettability and high interface bonding strength, so that the final cured product has excellent mechanical strength and heat resistance properties.

[0048] The epoxy resin composition of this embodiment has good processability and coating properties, and the cured product of the epoxy resin composition has excellent heat resistance and mechanical strength properties, which can meet the requirements of composite materials used in the automotive field and other fields for mechanics, heat resistance, lightness, and high strength. In addition, the prepreg and composite material raw materials provided by this embodiment are simple and easy to obtain, low in cost, and suitable for rapid and large-scale production.

[0049] Specific embodiment 7: The method for preparing epoxy resin prepreg using epoxy resin composition in this embodiment is carried out according to the following steps:

[0050] 1. Weigh the epoxy resin composition and carbon fiber;

[0051] 2. coating the epoxy resin composition with a film coating machine to obtain an epoxy resin film; the coating temperature of the film coating machine is 70 to 90° C., and the coating speed is 4 to 12 m / min;

[0052] 3. Laying the carbon fiber between two layers of epoxy resin films and performing hot pressing compounding to obtain carbon fiber prepreg.

[0053] The epoxy resin composition of this embodiment is composed of component A and component B, wherein component A is composed of liquid epoxy resin I and solid epoxy resin, and component B is composed of epoxy resin II, curing agent and accelerator. The preparation of component A is a high softening point solid epoxy resin melt mixing process, and the preparation process of component B is an auxiliary agent grinding process. The two-component design separates the preparation process to avoid the problem of high viscosity of the glue and uneven components caused by the simultaneous addition of solid epoxy resin and auxiliary agent. By selecting the type of resin, adjusting the resin ratio and the amount of auxiliary agent, the curing speed of the resin composition is adjusted, so that the coating process has a longer processing period, and the obtained adhesive film has uniform quality, which is suitable for the production of large quantities of prepregs.

[0054] In this embodiment, the addition of high softening point solid epoxy resin makes the resin composition have a higher viscosity at room temperature, and the prepared prepreg does not flow during storage or transportation at room temperature, and the size and shape do not change significantly after peeling off the release paper, which is beneficial to subsequent paving processing and curing, and effectively improves the stability of storage and transportation of the prepreg and the quality of the final cured product.

[0055] This embodiment uses a solid epoxy resin with high thermal stability and a multifunctional liquid epoxy resin as preparation raw materials. The solid epoxy resin used has excellent heat resistance, can maintain a stable chemical structure and physical properties at high temperatures, and has a small loss in mechanical properties; the multifunctional liquid epoxy resin forms a high-density cross-linked network through intermolecular cross-linking reactions; the selected curing agent and accelerator promote the intermolecular cross-linking reaction, forming a more compact and stable chemical structure, thereby improving the heat resistance of the cured product of the resin composition.

[0056] When the resin composition film of this embodiment is composited with fibers, the viscosity of the resin adhesive is low at the selected composite temperature, and the fibers can be completely impregnated, thereby avoiding problems such as pitting and dry yarn in the prepreg. The resin and fibers have good wettability and high interface bonding strength, so that the final cured product has excellent mechanical strength and heat resistance properties.

[0057] The epoxy resin composition of this embodiment has good processability and coating properties, and the cured product of the epoxy resin composition has excellent heat resistance and mechanical strength properties, which can meet the requirements of composite materials used in the automotive field and other fields for mechanics, heat resistance, lightness, and high strength. In addition, the prepreg and composite material raw materials provided by this embodiment are simple and easy to obtain, low in cost, and suitable for rapid and large-scale production.

[0058] Specific implementation eight: This implementation differs from specific implementation seven in that: in step one, the mass ratio of the epoxy resin to the carbon fiber is 30-45:55-70.

[0059] Specific embodiment 9: This embodiment is different from specific embodiment 7 in that: the surface density of the epoxy resin film in step 2 is 20-200g / m 2 .

[0060] Specific embodiment ten: This embodiment differs from specific embodiment seven in that: during the hot pressing and laminating in step three, the temperature of the pressing roller is 90-120° C., and the laminating speed is 4-12 m / min.

[0061] Example 1

[0062] The preparation method of the epoxy resin composition of this embodiment is carried out according to the following steps:

[0063] 1. Preparation of component A: Weigh 30 parts of glycidylamine type liquid epoxy resin and 70 parts of solid phenolic epoxy resin, heat to melt the solid phenolic epoxy resin, then add the glycidylamine type liquid epoxy resin, stir and mix well to obtain component A;

[0064] The softening point of the glycidylamine type liquid epoxy resin is 16°C;

[0065] The softening point of the solid phenolic epoxy resin is 85°C;

[0066] 2. Preparation of component B: 70 parts of glycidylamine type liquid epoxy resin, 5 parts of dicyandiamide type curing agent and 3 parts of organic urea are mixed and ground, heated to 70°C, and stirred to mix evenly to obtain component B;

[0067] The softening point of the glycidylamine type liquid epoxy resin is 16°C;

[0068] 3. Preparation of epoxy resin composition: Component A prepared in step 1 and component B prepared in step 2 are stirred and mixed at 80° C., and then cooled to obtain epoxy resin composition;

[0069] The mass ratio of component A to component B is 100:30;

[0070] The method for preparing epoxy resin prepreg using the above epoxy resin composition is carried out according to the following steps:

[0071] 1. Weighing an epoxy resin composition and carbon fiber; the mass ratio of the epoxy resin to the carbon fiber is 40:60; the carbon fiber is T700 grade carbon fiber;

[0072] 2. The epoxy resin composition is coated with a film coating machine to obtain an epoxy resin film; the coating temperature of the film coating machine is 75°C and the coating speed is 8m / min; the surface density of the epoxy resin film is 150g / m 2 ;

[0073] 3. The carbon fiber is laid between two layers of epoxy resin films and hot-pressed to obtain a carbon fiber prepreg; the temperature of the pressing roller during the hot-pressing is 115° C. and the compounding speed is 4 m / min.

[0074] The gram weight of the prepreg prepared in Example 1 is 357-364 g / m 2 The resin content is about 33.5% and the thickness is 0.22-0.24mm; the mechanical properties of the composite material prepared by the prepreg were tested, and the 0° tensile strength of the composite material reached 1805.41MPa, and the 0° unidirectional bending modulus was 109.52GPa, showing good mechanical properties.

[0075] Example 2

[0076] The preparation method of the epoxy resin composition of this embodiment is carried out according to the following steps:

[0077] 1. Preparation of component A: Weigh 30 parts of glycidylamine type liquid epoxy resin and 70 parts of solid phenolic epoxy resin, heat to melt the solid phenolic epoxy resin, then add the glycidylamine type liquid epoxy resin, stir and mix well to obtain component A;

[0078] The softening point of the glycidylamine type liquid epoxy resin is 12°C;

[0079] The softening point of the solid phenolic epoxy resin is 83°C;

[0080] 2. Preparation of component B: 80 parts of glycidylamine type liquid epoxy resin, 8 parts of dicyandiamide type curing agent and 4 parts of organic urea are mixed and ground, heated to 75° C., and stirred to mix evenly to obtain component B;

[0081] The softening point of the glycidylamine type liquid epoxy resin is 12°C;

[0082] 3. Preparation of epoxy resin composition: Component A prepared in step 1 and component B prepared in step 2 are stirred and mixed at 80° C., and then cooled to obtain epoxy resin composition;

[0083] The mass ratio of component A to component B is 100:25;

[0084] The method for preparing epoxy resin prepreg using the above epoxy resin composition is carried out according to the following steps:

[0085] 1. Weighing an epoxy resin composition and carbon fiber; the mass ratio of the epoxy resin to the carbon fiber is 40:60; the carbon fiber is T700 grade carbon fiber;

[0086] 2. The epoxy resin composition is coated with a film coating machine to obtain an epoxy resin film; the coating temperature of the film coating machine is 75°C and the coating speed is 8m / min; the surface density of the epoxy resin film is 158g / m 2 ;

[0087] 3. The carbon fiber is laid between two layers of epoxy resin films and hot-pressed to obtain a carbon fiber prepreg; during the hot-pressing, the temperature of the pressing roller is 120° C. and the laminating speed is 4 m / min.

[0088] The weight of the prepreg prepared in Example 2 is 358-362 g / m 2 The resin content is about 32.2% and the thickness is 0.22-0.24mm; the mechanical properties of the composite material prepared by the prepreg were tested, and the 0° tensile strength of the composite material reached 1780MPa, and the 0° unidirectional bending modulus was 108GPa, showing good mechanical properties.

[0089] Example 3

[0090] The preparation method of the epoxy resin composition of this embodiment is carried out according to the following steps:

[0091] 1. Preparation of component A: Take 40 parts of glycidylamine type liquid epoxy resin and 60 parts of solid o-cresol epoxy resin, heat to melt the solid o-cresol epoxy resin, then add the glycidylamine type liquid epoxy resin, stir and mix well to obtain component A;

[0092] The softening point of the glycidylamine type liquid epoxy resin is 18°C;

[0093] The softening point of the solid o-cresol epoxy resin is 89°C;

[0094] 2. Preparation of component B: 65 parts of bisphenol A liquid epoxy resin, 5 parts of dicyandiamide curing agent and 2 parts of organic urea are mixed and ground, heated to 75° C., and stirred to mix evenly to obtain component B;

[0095] The softening point of the bisphenol A type liquid epoxy resin is 17°C;

[0096] 3. Preparation of epoxy resin composition: Component A prepared in step 1 and component B prepared in step 2 are stirred and mixed at 80° C., and then cooled to obtain epoxy resin composition;

[0097] The mass ratio of component A to component B is 100:35;

[0098] The method for preparing epoxy resin prepreg using the above epoxy resin composition is carried out according to the following steps:

[0099] 1. Weighing an epoxy resin composition and carbon fiber; the mass ratio of the epoxy resin to the carbon fiber is 40:60; the carbon fiber is T700 grade carbon fiber;

[0100] 2. The epoxy resin composition is coated with a film coating machine to obtain an epoxy resin film; the coating temperature of the film coating machine is 75°C and the coating speed is 8m / min; the surface density of the epoxy resin film is 155g / m 2 ;

[0101] 3. The carbon fiber is laid between two layers of epoxy resin films and hot-pressed to obtain a carbon fiber prepreg; during the hot-pressing, the temperature of the pressing roller is 115° C. and the laminating speed is 5 m / min.

[0102] The weight of the prepreg prepared in Example 3 is 359-363 g / m 2 The resin content is about 33.5% and the thickness is 0.22-0.24mm; the mechanical properties of the composite material prepared by the prepreg were tested, and the 0° tensile strength of the composite material reached 1790MPa, and the 0° unidirectional bending modulus was 107GPa, showing good mechanical properties.

Claims

1. An epoxy resin composition, characterized in that: The epoxy resin composition consists of component A and component B; the mass ratio of component A to component B is 100:(20-40); The component A is composed of liquid epoxy resin I and solid epoxy resin; the liquid epoxy resin I is 20 to 50 parts and the solid epoxy resin is 40 to 80 parts in the component A; The B component is composed of liquid epoxy resin II, curing agent and accelerator; the B component contains 60-90 parts of liquid epoxy resin II, 2-10 parts of curing agent and 1-5 parts of accelerator; The softening point of the solid epoxy resin is 55-95°C; the softening points of the liquid epoxy resin I and the liquid epoxy resin II are lower than 25°C.

2. The epoxy resin composition according to claim 1, characterized in that: The curing agent is a dicyandiamide curing agent.

3. The epoxy resin composition according to claim 1, characterized in that: The liquid epoxy resin I is a liquid bisphenol A epoxy resin, a liquid alicyclic epoxy resin, a liquid aliphatic epoxy resin, a liquid bisphenol F epoxy resin, a liquid phenolic epoxy resin or a liquid glycidylamine epoxy resin.

4. The epoxy resin composition according to claim 1, characterized in that: The liquid epoxy resin II is a liquid bisphenol A epoxy resin, a liquid alicyclic epoxy resin, a liquid aliphatic epoxy resin, a liquid bisphenol F epoxy resin, a liquid phenolic epoxy resin or a liquid glycidylamine epoxy resin.

5. The epoxy resin composition according to claim 1, characterized in that: The accelerator is organic urea.

6. The method for preparing the epoxy resin composition according to claim 1, wherein: The preparation method of the epoxy resin composition is carried out according to the following steps:

1. Preparation of component A: heat to melt the solid epoxy resin, then add the liquid epoxy resin I, stir and mix evenly to obtain component A; 2. Preparation of component B: Mix and grind the liquid epoxy resin II, the curing agent and the accelerator, heat to 55-85°C, stir and mix evenly to obtain component B; 3. Preparation of epoxy resin composition: Component A prepared in step 1 and component B prepared in step 2 are stirred and mixed at 55-85° C., and then cooled to obtain an epoxy resin composition.

7. The use of the epoxy resin composition according to claim 1, characterized in that: Using the epoxy resin composition to prepare epoxy resin prepreg; The method for preparing epoxy resin prepreg using epoxy resin composition is carried out according to the following steps:

1. Weigh the epoxy resin composition and carbon fiber; 2. coating the epoxy resin composition with a film coating machine to obtain an epoxy resin film; the coating temperature of the film coating machine is 70 to 90° C., and the coating speed is 4 to 12 m / min; 3. Laying the carbon fiber between two layers of epoxy resin films and performing hot pressing compounding to obtain carbon fiber prepreg.

8. The use according to claim 7, characterized in that: In step 1, the mass ratio of the epoxy resin to the carbon fiber is 30-45:55-70.

9. The use according to claim 7, characterized in that: Step 2: The surface density of the epoxy resin film is 20-200 g / m 2 .

10. The use according to claim 7, characterized in that: In step 3, during the hot pressing and laminating, the temperature of the pressing roller is 90-120° C., and the laminating speed is 4-12 m / min.