Maleimide resin composition resistant to high temperature of 300 DEG C, preparation method and prepreg

Abstract

The invention relates to a maleimide resin composition resistant to a high temperature of 300 DEG C, a preparation method and a prepreg, and belongs to the technical field of manufacturing of hot-melt prepregs for structural composite materials. The maleimide resin can endow a maleimide system with a higher glass transition temperature, so that the designability of the maleimide resin resistant to the high temperature of 300 DEG C and the heat resistance and the high-temperature retention rate of a corresponding composite material are improved, and meanwhile, the thermoplastic resin is added for process regulation and control and dissolution thickening; the resin composition has the advantages of being resistant to the high temperature of 300 DEG C, good in manufacturability and the like, and is suitable for manufacturing of aerospace main bearing composite material parts.

Description

Technical Field

[0001] The present invention relates to a hot-melt high-temperature resistant maleimide resin composition, in particular to a 300°C high-temperature resistant maleimide resin composition, a preparation method and a hot-melt prepreg comprising the hot-melt high-temperature resistant maleimide resin; and belongs to the technical field of hot-melt prepreg manufacturing for structural composite materials. Background Art

[0002] Bismaleimide resin (BMI) and its hot-melt prepreg are widely used in the manufacture of composite components with temperature resistance requirements for aviation and aerospace main load-bearing structures due to its excellent high temperature resistance, radiation resistance, good mechanical properties and dimensional stability. At present, the research and development of bismaleimide resins is mainly focused on improving the temperature resistance level and improving the impact strength. The high-temperature resistant bismaleimide resins used in the main load-bearing structural parts of aerospace are generally used at a temperature of about 230℃ to 260℃. For example, the Institute of Aerospace Materials and Technology has developed a high-temperature resistant hot-melt bismaleimide resin 802 with a glass transition temperature of 308℃. The strength performance retention rate of its composite material at 230℃ can reach more than 70%. It is a relatively mature material system for the manufacture of aerospace main load-bearing structures. Its long-term use temperature is designed to be 230-250℃. The 625th Institute of Aviation has developed the QY260 series of bismaleimide resins, whose 260℃ (wet state) short beam shear strength retention rate is about 50%, and its long-term use temperature can reach 260℃. However, there are few studies or reports on the development of high-temperature resistant bismaleimide resins and their composite materials that meet the hot-melt prepreg process and can be used at temperatures of 300°C or higher. It is urgently needed to develop a bismaleimide resin system with higher temperature resistance and good process applicability based on the existing 230°C resistant bismaleimide resin to meet the high temperature resistance requirements of aerospace equipment, and to replace PMR-15 grade polyimide composite materials in certain application scenarios to achieve better process controllability.

[0003] Therefore, how to provide a maleimide resin composition that can withstand an operating temperature of 300°C or higher through technical optimization, effectively improve the temperature resistance level of the composite material while maintaining good processability of the material is a key technical issue in whether its application can be further expanded. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a maleimide resin composition resistant to high temperatures of 300°C. A new type of multifunctional maleimide monomer containing both maleimide and cyano is synthesized, and a thermoplastic resin is added to perform process control and dissolution thickening to meet the hot melt preparation process requirements and the curing process requirements in the composite material molding process. The resin composition has the advantages of resistance to high temperatures of 300°C and good processability, and is suitable for the manufacture of main load-bearing composite material components for aerospace.

[0005] Another object of the present invention is to provide a method for preparing a maleimide resin composition resistant to high temperatures of 300°C.

[0006] Another object of the present invention is to provide a prepreg and a composite material of a maleimide resin composition resistant to high temperatures of 300°C.

[0007] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0008] A 300°C high temperature resistant maleimide resin composition comprises the following components in parts by weight:

[0009]

[0010] The maleimide monomer is a maleimide monomer 2PH-BMI containing two cyano groups, and the chemical structure is shown below:

[0011]

[0012] In the above maleimide resin composition resistant to high temperature of 300° C., the average particle size of the maleimide monomer is ≤10 μm.

[0013] In the above maleimide resin composition resistant to high temperature of 300° C., the average particle size of the maleimide monomer is ≤6 μm.

[0014] In the above maleimide resin composition resistant to high temperature of 300° C., the process modifier is one or a combination of tetraallyl bisphenol A or phenolic cyanate.

[0015] In the above maleimide resin composition resistant to high temperature of 300°C, the rheology control agent is a polyimide thermoplastic resin having a glass transition temperature of not less than 300°C.

[0016] In the above maleimide resin composition resistant to high temperature of 300° C., the multifunctional epoxy resin is one or a combination of p-aminophenol glycidylamine or m-aminophenol glycidylamine.

[0017] In the above-mentioned 300° C. high temperature resistant maleimide resin composition, the maleimide monomer is prepared by the following method:

[0018] (1) adding a solution of 4-amino-4-phenoxy-phthalonitrile 2PH in N,N-dimethylacetamide dropwise to a solution of maleic anhydride in toluene, controlling the dropping speed so that the temperature does not exceed 10° C.; after the dropping is complete, reacting at 20° C. to 30° C. for 120 to 180 minutes;

[0019] (2) adding p-toluenesulfonic acid to the above system, heating to 100° C. to 120° C. under nitrogen protection, and performing water separation reaction for 240 min to 300 min;

[0020] (3) Toluene is evaporated to remove the precipitated product, which is further washed with distilled water and vacuum dried to a constant weight to obtain a maleimide monomer 2PH-BMI.

[0021] In the above maleimide resin composition resistant to high temperature of 300° C., the molar ratio of the 4-amino-4-phenoxy-phthalonitrile 2PH, maleic anhydride and p-toluenesulfonic acid is 1:1.15-1.30:0.10-0.25.

[0022] In the above-mentioned 300°C high temperature resistant maleimide resin composition, the concentration of the N,N-dimethylacetamide solution of 4-amino-4-phenoxy-phthalonitrile 2PH is 1.5mol / L to 3.0mol / L; the concentration of the toluene solution of maleic anhydride is 0.4mol / L to 0.6mol / L.

[0023] In the above-mentioned 300° C. high temperature resistant maleimide resin composition, in the step (3), the maleimide monomer 2PH-BMI is obtained by vacuum drying at 80° C. to 120° C. to a constant weight and grinding.

[0024] The preparation method of the above-mentioned 300°C high temperature resistant maleimide resin composition comprises the following steps:

[0025] (1) In a double planetary stirred reactor, the process modifier, rheology control agent and multifunctional epoxy are heated to 100-130° C. and dissolved and mixed evenly;

[0026] (2) Cooling the material obtained in step (1) to below 60-90° C., then adding the maleimide monomer, mechanically stirring and mixing, and then cooling to room temperature to obtain a maleimide resin composition.

[0027] A hot-melt prepreg comprises the above-mentioned 300°C high-temperature resistant maleimide resin composition and reinforcing fibers; the mass percentage content of the hot-melt high-temperature resistant maleimide resin composition in the hot-melt prepreg is 30% to 50%; the reinforcing fibers are carbon fibers or glass fibers.

[0028] A fiber-reinforced composite material is obtained by curing and molding the hot-melt prepreg.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects:

[0030] (1) In the embodiments of the present invention, the maleimide monomer 2PH-BMI with higher intrinsic heat resistance is used. Since it contains three multifunctional reactive groups of two types, namely cyano and maleimide, it can give the maleimide system a higher glass transition temperature, thereby improving the designability of the 300°C high temperature resistant maleimide resin and the heat resistance and high temperature retention rate of the corresponding composite material.

[0031] (2) In the embodiment of the present invention, it is further preferred to use a process modifier that can participate in cross-linking tetraallyl bisphenol A or phenolic cyanate ester and is a low-viscosity liquid, which can take into account both the high temperature resistance and processability of the material; at the same time, it is preferred to use a soluble polyimide thermoplastic resin with a glass transition temperature of not less than 300°C, which gives the system better film-forming properties and ensures that the final system will not be affected by the overall high-temperature performance when subjected to a high temperature above 300°C due to the addition of the thermoplastic resin.

[0032] (3) In the embodiment of the present invention, one or a combination of p-aminophenol glycidylamine or m-aminophenol glycidylamine is further preferred. The above-mentioned epoxy resin can well dissolve the high-temperature resistant polyimide thermoplastic resin used as the rheology control agent, play a role in rheology control, and the multifunctional epoxy can participate in the cross-linking of maleimide without affecting the temperature resistance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is an infrared spectrum of the maleimide monomer 2PH-BMI in an embodiment of the present invention;

[0034] Figure 2 The DSC spectrum of the maleimide monomer 2PH-BMI in the embodiment of the present invention (heating rate 10°C / min);

[0035] Figure 3 This is the H NMR spectrum of the maleimide monomer 2PH-BMI in the example of the present invention (using DMSO as the solvent). DETAILED DESCRIPTION

[0036] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0037] The 300°C high temperature resistant maleimide resin composition of the present invention comprises the following components in parts by weight:

[0038] Maleimide monomer: 100 parts;

[0039] Process modifier: 40-80 parts;

[0040] Rheology control agent: 5-40 parts;

[0041] Multifunctional epoxy resin: 2-15 parts

[0042] The chemical structure of the maleimide monomer is shown in formula (I), which is a maleimide monomer 2PH-BMI containing two cyano groups:

[0043]

[0044] In an optional embodiment, the average particle size of the maleimide monomer is ≤10 μm, preferably ≤6 μm. Ultrafine maleimide monomer is advantageous for adding in the form of slurry during subsequent preparation to achieve more uniform dispersion without affecting the processability and paving properties of the material.

[0045] In an optional embodiment, the maleimide monomer 2PH-BMI contains two types of three multifunctional reactive groups, namely cyano and maleimide, which can give the maleimide system a higher glass transition temperature, thereby improving the heat resistance of the corresponding composite material.

[0046] In an optional embodiment, the process modifier is one or a combination of tetraallyl bisphenol A or phenolic cyanate. The above process modifiers are liquid at room temperature and contain multifunctional reactive groups that react with maleimide monomers, which can take into account the high temperature resistance and processability of the material;

[0047] In an optional embodiment, the rheology control agent is a polyimide thermoplastic resin having a glass transition temperature of not less than 300°C, preferably commercially available P84 (glass transition temperature 365°C) or 5218 (glass transition temperature 335°C) polyimide resin. Since the glass transition temperatures of the two rheology control agents are greater than 300°C, the addition of thermoplastic resin will not affect the overall high temperature performance of the final system when subjected to high temperatures above 300°C.

[0048] In an optional embodiment, the multifunctional epoxy resin is one or a combination of p-aminophenol glycidylamine or m-aminophenol glycidylamine. This is mainly because the above-mentioned epoxy resin can dissolve the high-temperature resistant polyimide thermoplastic resin mentioned in the rheology control agent well, play a role in rheology control, and the multifunctional epoxy can participate in the cross-linking of maleimide without affecting the temperature resistance of the system. Other epoxy resins such as bisphenol A epoxy, bisphenol F epoxy, diphenylmethane tetraglycidylamine, etc. cannot dissolve the above-mentioned thermoplastic resin and cannot play a role in rheology control.

[0049] The hot-melt high temperature resistant maleimide resin composition of the present invention is prepared according to the following method:

[0050] S1. Preparation of novel maleimide monomer 2PH-BMI

[0051] (1) Add the N,N-dimethylacetamide solution of 4-amino-4-phenoxy-phthalonitrile (2PH) dropwise to the toluene solution of maleic anhydride, and control the dropping speed so that the temperature does not exceed 10°C; after the dropwise addition is completed, react at a temperature of 20°C to 30°C for 120-180 minutes;

[0052] (2) Add p-toluenesulfonic acid to the above system, heat to 100°C to 120°C under nitrogen protection, and carry out water separation reaction at this temperature for 240min to 300min;

[0053] (3) After the reaction is completed, the toluene is evaporated to remove the product, which is further washed with distilled water, vacuum dried at 80°C to 120°C to constant weight, and cryogenically ground to obtain 2PH-BMI maleimide monomer.

[0054] In an optional embodiment, the molar ratio of 4-amino-4-phenoxy-phthalonitrile 2PH, maleic anhydride and p-toluenesulfonic acid is 1:1.15-1.30:0.10-0.25.

[0055] In an optional embodiment, the concentration of the N,N-dimethylacetamide solution of 4-amino-4-phenoxy-phthalonitrile 2PH is 1.5 mol / L to 3.0 mol / L; the concentration of the toluene solution of maleic anhydride is 0.4 mol / L to 0.6 mol / L.

[0056] The following is the synthesis process of 2PH-BMI maleimide monomer:

[0057]

[0058] S2. Preparation of hot-melt high temperature resistant maleimide resin composition

[0059] (1) In a double planetary stirred reactor, the process modifier, rheology control agent and multifunctional epoxy are heated to 100-130°C and dissolved and mixed evenly;

[0060] (2) The material obtained in step (1) is cooled to below 60-90° C., and then maleimide monomer is added, mechanically stirred / dispersed and mixed uniformly, and then cooled to room temperature to obtain a resin composition.

[0061] The present invention also provides a hot melt prepreg, comprising the above-mentioned 300°C high temperature resistant maleimide resin composition and reinforcing fiber; the mass percentage content of the hot melt high temperature resistant maleimide resin composition in the hot melt prepreg is 30% to 50%. The reinforcing fiber is preferably carbon fiber or glass fiber;

[0062] The present invention also provides a fiber-reinforced composite material, which is obtained by curing and molding the hot-melt prepreg.

[0063] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0064] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0065] The preparation methods of maleimide monomer, hot-melt high-temperature resistant maleimide resin composition, glass transition temperature of hot-melt high-temperature resistant maleimide resin cured product, and 0° flexural strength and 0° interlaminar shear strength of composite materials in the following embodiments are as follows:

[0066] (1) Maleimide monomer

[0067] Maleimide monomer (self-made).

[0068] (2) Process modifier

[0069] Tetraallyl bisphenol A (Institute of Chemistry, Chinese Academy of Sciences);

[0070] Phenolic cyanate ester (Yangzhou Tianqi).

[0071] (3) Rheology control agent

[0072] Polyimide P84 (Evonik);

[0073] Polyimide 5218 (Huntsman).

[0074] (4) Multifunctional epoxy resin

[0075] p-Aminophenol glycidylamine MY-510 (Huntsman);

[0076] m-Aminophenol glycidylamine MY-610 (Huntsman).

[0077] (5) Synthesis of maleimide monomer 2PH-BMI

[0078] (a) Add maleic anhydride solution (0.175 mol, 17.16 g, 355 ml toluene) to a 1000 ml three-necked flask, and then add 2PH solution (0.14 mol, 32.9 g, 70 ml DMAC) dropwise, and control the dropping speed so that the temperature does not exceed 10°C; after the addition is complete, react at 25°C for 3 hours; (b) Add 0.028 mol p-toluenesulfonic acid (5.33 g) to the above system, heat to about 110°C, the solution is a dark brown transparent solution, heat to boiling and separate water, separate water and react for 5 hours before cooling; (c) After the reaction is completed, evaporate to remove toluene, and a product is precipitated. The precipitate is further washed with distilled water, and vacuum dried at 100°C to constant weight to obtain 2PH-BMI maleimide monomer. 2PH-BMI molecular formula: C 19 H9N3O3, the positions of various hydrogen species in the nuclear magnetic resonance analysis are consistent with the theoretical values, the hydrogen spectrum has no impurity peaks, and the number ratio of hydrogen protons at different positions in the 2P-BMI monomer is consistent with the area ratio in the corresponding hydrogen spectrum, indicating that the maleimide monomer of the target molecular structure has been synthesized. The maleimide monomer 2PH-BMI synthesized in this step is used in the following Examples 1 to 3.

[0079] like Figure 1 The infrared spectrum of maleimide monomer 2PH-BMI in the embodiment of the present invention is shown in FIG. 1706 cm -1 , C=O absorption peak on the imine ring; 1683cm -1 , NH deformation vibration absorption peak; 1510cm -1 , absorption peak of skeleton vibration of benzene ring; 1398cm -1 , O=CN absorption peak on the imine ring; 692cm -1 , deformation vibration absorption peak of C=CH on the imine ring; 2231cm -1 , -CN group stretching vibration absorption peak.

[0080] like Figure 2 The DSC spectrum of the maleimide monomer 2PH-BMI in the embodiment of the present invention is shown (heating rate 10°C / min); it can be seen from the figure that the melting point of the maleimide monomer 2PH-BMI is 217.6°C.

[0081] like Figure 3 The figure shows the H NMR spectrum of the maleimide monomer 2PH-BMI in the embodiment of the present invention (using DMSO as solvent). It can be seen from the H NMR spectrum that the H spectrum and proportion of the maleimide monomer 2PH-BMI have a good correspondence.

[0082] (6) Preparation of hot-melt high temperature resistant maleimide resin composition

[0083] In a double planetary stirring reactor, the process modifier, rheology control agent and multifunctional epoxy are heated to 100-130° C. and dissolved and mixed evenly; the above-obtained materials are cooled to below 60-90° C., and then maleimide monomer is added, mechanically stirred / dispersed and mixed evenly, and then cooled to room temperature to obtain the resin composition.

[0084] (7) Preparation of fiber-reinforced composite materials

[0085] The preparation of fiber reinforced composite materials can be done by pre-forming resin and fiber into prepreg and then performing layering and curing. The mass percentage content of the hot melt high temperature resistant maleimide resin composition in the hot melt prepreg is 30% to 50%. The reinforcing fiber is carbon fiber or glass fiber.

[0086] The present invention takes prepreg as an example, uses a coating device to coat the hot-melt high-temperature resistant maleimide resin composition prepared in (6) above onto release paper to make a resin film, and then laminates the film on both sides of unidirectionally paralleled carbon fibers (such as Toray T800H-12K), and uses a hot roller to heat and pressurize at a temperature of 100° C. to fully impregnate the resin composition with the carbon fibers (resin content 34%) to obtain a hot-melt prepreg. The prepreg is cured in an autoclave at 250° C. for 5 hours to obtain a fiber-reinforced composite material.

[0087] (8) Performance testing of cured resins and composite materials

[0088] The hot-melt high-temperature resistant maleimide resin composition and the fiber-reinforced composite material are cured according to the procedure of 125°C / 1h+185°C / 2h+250°C5h;

[0089] The glass transition temperature of the cured resin is tested according to ASTM D 7028;

[0090] The bending properties of fiber reinforced composite materials are tested according to GB / 3356 standard;

[0091] The 0° interlaminar shear strength of fiber reinforced composite materials was tested according to JC / T 773 standard.

[0092] Example 1

[0093] (1) In a double planetary stirred reactor, a process modifier (50 parts of tetraallyl bisphenol A), a rheology control agent (20 parts of P84 thermoplastic resin) and a multifunctional epoxy (5 parts of p-aminophenol glycidylamine) were heated to 130° C. and dissolved and mixed uniformly;

[0094] (2) The material obtained in step (1) is cooled to 75° C., and then the maleimide monomer synthesized above (100 parts of 2PH-BMI maleimide monomer) is added, mechanically stirred / dispersed and mixed evenly, and then cooled to room temperature to obtain a hot-melt high-temperature resistant maleimide resin composition.

[0095] The glass transition temperature of the cured resin is 420°C;

[0096] The reinforcing fiber used in the hot-melt prepreg is T800H-12K carbon fiber with a resin content of 34%;

[0097] The 0° flexural strength of the fiber-reinforced composite material is 1800MPa, and the 0° flexural strength at 300°C is 1350MPa;

[0098] The 0° interlaminar shear strength of the fiber-reinforced composite material is 105MPa, and the 0° interlaminar shear strength at 300°C is 74MPa;

[0099] Example 2

[0100] (1) In a double planetary stirred reactor, a process modifier (80 parts of tetraallyl bisphenol A), a rheology control agent (40 parts of P84 thermoplastic resin) and a multifunctional epoxy (15 parts of p-aminophenol glycidylamine) were heated to 100° C. and dissolved and mixed uniformly;

[0101] (2) The material obtained in step (1) is cooled to 60° C., and then the maleimide monomer synthesized above (100 parts of 2PH-BMI maleimide monomer) is added, mechanically stirred / dispersed and mixed evenly, and then cooled to room temperature to obtain a hot-melt high-temperature resistant maleimide resin composition.

[0102] The glass transition temperature of the cured resin is 390°C;

[0103] The reinforcing fiber used in the hot-melt prepreg is T800H-12K carbon fiber with a resin content of 34%;

[0104] The 0° flexural strength of the fiber-reinforced composite material is 1750MPa, and the 0° flexural strength at 300°C is 1150MPa;

[0105] The 0° interlaminar shear strength of the fiber-reinforced composite material is 103MPa, and the 0° interlaminar shear strength at 300°C is 63MPa;

[0106] Example 3

[0107] (1) In a double planetary stirred reactor, a process modifier (60 parts of phenolic cyanate ester), a rheology control agent (30 parts of P84 thermoplastic resin) and a multifunctional epoxy (10 parts of m-aminophenol glycidylamine) were heated to 120° C. and dissolved and mixed uniformly;

[0108] (2) The material obtained in step (1) is cooled to 90° C., and then the maleimide monomer synthesized above (100 parts of 2PH-BMI maleimide monomer) is added, mechanically stirred / dispersed and mixed evenly, and then cooled to room temperature to obtain a hot-melt high-temperature resistant maleimide resin composition.

[0109] The glass transition temperature of the cured resin is 360°C;

[0110] The reinforcing fiber used in the hot-melt prepreg is T800H-12K carbon fiber with a resin content of 34%;

[0111] The 0° flexural strength of the fiber-reinforced composite material is 1600MPa, and the 0° flexural strength at 300°C is 1180MPa;

[0112] The 0° interlaminar shear strength of the fiber reinforced composite material is 105MPa, and the 0° interlaminar shear strength at 300°C is 56MPa.

[0113] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0114] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A 300°C high temperature resistant maleimide resin composition, characterized in that: Contains the following components by mass: The maleimide monomer is a maleimide monomer 2PH-BMI containing two cyano groups, and the chemical structure is as follows:

2. The 300°C high temperature resistant maleimide resin composition according to claim 1, characterized in that: The average particle size of the maleimide monomer is ≤10 μm.

3. The 300°C high temperature resistant maleimide resin composition according to claim 2, characterized in that: The average particle size of the maleimide monomer is ≤6 μm.

4. The 300°C high temperature resistant maleimide resin composition according to claim 1, characterized in that: The process modifier is one or a combination of tetraallyl bisphenol A or phenolic cyanate.

5. The 300°C high temperature resistant maleimide resin composition according to claim 1, characterized in that: The rheology control agent is a polyimide thermoplastic resin with a glass transition temperature of not less than 300°C.

6. The 300°C high temperature resistant maleimide resin composition according to claim 1, characterized in that: The multifunctional epoxy resin is one or a combination of p-aminophenol glycidylamine and m-aminophenol glycidylamine.

7. The 300°C high temperature resistant maleimide resin composition according to claim 1, characterized in that: The maleimide monomer is prepared by the following method: (1) adding a solution of 4-amino-4-phenoxy-phthalonitrile 2PH in N,N-dimethylacetamide dropwise to a solution of maleic anhydride in toluene, controlling the dropping speed so that the temperature does not exceed 10° C.; after the dropping is complete, reacting at 20° C. to 30° C. for 120 to 180 minutes; (2) adding p-toluenesulfonic acid to the above system, heating to 100° C. to 120° C. under nitrogen protection, and performing water separation reaction for 240 min to 300 min; (3) Toluene is evaporated to remove the precipitated product, which is further washed with distilled water and vacuum dried to a constant weight to obtain a maleimide monomer 2PH-BMI.

8. The 300°C high temperature resistant maleimide resin composition according to claim 7, characterized in that: The molar ratio of the 4-amino-4-phenoxy-phthalonitrile 2PH, maleic anhydride and p-toluenesulfonic acid is 1:1.15-1.30:0.10-0.

25.

9. The 300°C high temperature resistant maleimide resin composition according to claim 7, characterized in that: The concentration of the N,N-dimethylacetamide solution of 4-amino-4-phenoxy-phthalonitrile 2PH is 1.5 mol / L to 3.0 mol / L; the concentration of the toluene solution of maleic anhydride is 0.4 mol / L to 0.6 mol / L.

10. The 300°C high temperature resistant maleimide resin composition according to claim 7, characterized in that: In the step (3), the maleimide monomer 2PH-BMI is obtained by vacuum drying at 80° C. to 120° C. to a constant weight and grinding.

11. The method for preparing the 300°C high temperature resistant maleimide resin composition according to any one of claims 1 to 10, characterized in that: The steps include: (1) In a double planetary stirred reactor, the process modifier, rheology control agent and multifunctional epoxy are heated to 100-130° C. and dissolved and mixed evenly; (2) Cooling the material obtained in step (1) to below 60-90° C., then adding the maleimide monomer, mechanically stirring and mixing, and then cooling to room temperature to obtain a maleimide resin composition.

12. A hot melt prepreg, characterized in that: It comprises the 300°C high temperature resistant maleimide resin composition as claimed in any one of claims 1 to 10 and reinforcing fibers; the mass percentage content of the hot melt high temperature resistant maleimide resin composition in the hot melt prepreg is 30% to 50%; and the reinforcing fibers are carbon fibers or glass fibers.

13. A fiber-reinforced composite material, characterized in that: The hot-melt prepreg according to claim 12 is cured and formed.

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