Hot-melting bismaleimide resin matrix, prepreg, composite material and preparation method of hot-melting bismaleimide resin matrix

Abstract

The invention provides a hot-melt bismaleimide resin matrix, a prepreg, a composite material and a preparation method thereof, and the hot-melt bismaleimide resin matrix is characterized by comprising the following preparation raw materials by mass: 70-100 parts of a bismaleimide resin monomer, 50-65 parts of a process modifier, 20-35 parts of an active diluent, 10-15 parts of a toughening modifier, and 10-20 parts of a heat-resistant modifier; wherein the bismaleimide resin monomer is one or a mixture of two of a diphenylmethane diamine type bismaleimide monomer and a diphenyl ether diamine type bismaleimide monomer. The hot-melt bismaleimide resin prepreg prepared by the method is stable in resin content, uniform in resin distribution, low in volatile matter content and good in laying property; and the prepared double-horse-based prepreg is suitable for various composite material forming processes, and the application field of the prepreg is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a hot-melt bismaleimide resin matrix, a prepreg, a composite material and a preparation method thereof. Background Art

[0002] With the continuous development of aerospace weapons and equipment, further requirements are put forward for the temperature resistance and mechanical properties of structural composite materials. Carbon fiber / epoxy composite materials can no longer meet the high temperature resistance requirements. Bismaleimide resin has unique advantages such as excellent heat resistance, good mechanical properties and dimensional stability, and has become a key raw material for manufacturing high temperature resistant parts for aviation and aerospace. The Chinese patent document with publication number CN116426123A discloses a bismaleimide resin composition, a composite material and a preparation method thereof. The bismaleimide resin composition includes the following components in mass fractions: 100 parts of bismaleimide resin, 30-50 parts of allylphenoloxy resin, and 20-45 parts of diallyl bisphenol A; the raw materials for the preparation of allylphenoloxy resin include diallyl phenol, flexible side chain modified epoxy resin, and catalyst; the mass ratio of diallyl phenol: flexible side chain modified epoxy resin: catalyst is 1:0.4-0.5:0.05-0.15. In the bismaleimide resin composition, the bismaleimide resin reacts with the allyl group in the allyl phenoloxy resin and diallyl bisphenol A with the active C=C on the bismaleimide resin ring to generate a tough resin with a high cross-linking degree and a ring structure, thereby improving the toughness of the bismaleimide resin, and introducing a flexible segment into the bismaleimide resin through the allyl phenoloxy resin, further improving the toughness of the bismaleimide resin, and improving the impact resistance of the bismaleimide resin. However, the existing bismaleimide resin has the disadvantages of high melting point, poor solubility, high molding temperature, large brittleness of the cured product, and insufficient toughness and temperature resistance, which limits its application range.

[0003] There are two common prepreg molding methods, solution method and hot melt method. The solution method is a process in which the fabric is impregnated with a resin solution, the solvent in the solution is evaporated, and the prepreg reaches the B stage. However, the prepreg prepared by the solution method has problems such as difficult to accurately control the resin content, high volatile content, and environmental pollution.

[0004] Therefore, it is necessary to provide a bismaleimide resin with stronger toughness and temperature resistance, and it is necessary to provide a method for preparing a bismaleimide resin-based prepreg with low volatile content and capable of accurately controlling the resin content in the prepreg. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a hot-melt bismaleimide resin matrix, prepreg, composite material and preparation method thereof, aiming to overcome the problems of difficult to accurately control the resin content of the solution process, high volatile content, environmental pollution and the like.

[0006] In order to solve the above problems, the first aspect of the present invention provides a hot-melt bismaleimide resin matrix, the raw materials for preparing the matrix include the following components in parts by weight:

[0007] 70-100 parts of bismaleimide resin monomer, 50-65 parts of process modifier, 20-35 parts of active diluent, 10-15 parts of toughening modifier, 10-20 parts of heat-resistant modifier;

[0008] Wherein, the bismaleimide resin monomer is a mixture of one or both of diphenylmethane diamine type bismaleimide monomer and diphenyl ether diamine type bismaleimide monomer.

[0009] Preferably, the bismaleimide resin monomer is a mixture of diphenylmethane diamine type bismaleimide monomer and diphenyl ether diamine type bismaleimide monomer, wherein the mass percentage content of the diphenylmethane diamine type bismaleimide monomer is 50%-100%, and is not 100%.

[0010] Preferably, the process modifier is diallyl bisphenol A; the active diluent is a mixture of toluene and dipropylene phthalate, and the mass ratio of toluene to dipropylene phthalate is 1:0.4-1.6; the toughening modifier is a mixture of one or two of polyaryletherketone and polyimide; the heat-resistant modifier is a mixture of one or two of terminal maleimide branched polysiloxane and aromatic heterocyclic resin.

[0011] The second aspect of the present invention provides a method for preparing the above-mentioned hot-melt bismaleimide resin matrix, comprising the following steps:

[0012] S1: Weigh the bismaleimide resin monomer, the process modifier, the reactive diluent, the toughening modifier and the heat-resistant modifier according to their mass fractions;

[0013] S2: mixing the process modifier and the reactive diluent to obtain a mixture;

[0014] S3: adding the bismaleimide resin monomer and the toughening modifier to the mixture, heating, then cooling, removing toluene, and finally adding the heat-resistant modifier, and mixing to obtain the hot-melt bismaleimide resin matrix.

[0015] Preferably, in step S2, the process modifier and the reactive diluent are mixed at 30 to 50° C. for 20 to 30 minutes.

[0016] Preferably, step S3 specifically includes: adding the bismaleimide resin monomer and the toughening modifier to the mixture, heating to 120-150°C and keeping warm for 1-2 hours, then cooling to 90-110°C, then removing toluene in vacuo, and finally adding the heat-resistant modifier, and blending for 10-30 minutes to obtain the hot-melt bismaleimide resin matrix.

[0017] The third aspect of the present invention provides a hot-melt bismaleimide resin-based prepreg, comprising the hot-melt bismaleimide resin matrix and a reinforcing material.

[0018] A fourth aspect of the present invention provides a method for preparing the above-mentioned hot-melt bismaleimide resin-based prepreg, comprising the following steps:

[0019] A1: Melting the hot-melt bismaleimide resin matrix;

[0020] A2: Use the coating device of the hot melt prepreg machine to coat the molten hot melt bismaleimide resin matrix into a bismaleimide resin film, and control the surface density of the bismaleimide resin film by adjusting the roller gap and coating speed;

[0021] A3: Place reinforcing materials between the bismaleimide resin film layers, use the composite device of the hot melt prepreg machine, and hot-press the bismaleimide resin film and the reinforcing materials through a pressure roller to obtain a hot melt bismaleimide resin-based prepreg.

[0022] Preferably, step A1 specifically comprises: heating the bismaleimide resin at 70-110° C. for 0.5-2 h to melt the bismaleimide resin; in step A2, the surface density of the bismaleimide resin film is controlled at 30-200 g / m 2 , the coating temperature is 70-110°C, and the coating speed is controlled at 2-10 m / min; in step A3, the pressure roller temperature is controlled at 80-120°C, the pressure roller gap is controlled at 120-800 μm, and the dipping speed is controlled at 2-8 m / min.

[0023] A fifth aspect of the present invention provides a bismaleimide resin-based composite material, which is obtained by curing and molding the above-mentioned hot-melt bismaleimide resin-based prepreg.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The preparation method of the hot-melt bismaleimide resin matrix of the present invention adds an active diluent during the synthesis process of the bismaleimide resin, thereby reducing the viscosity of the bismaleimide resin, so that the bismaleimide resin meets the requirements of hot-melt coating at a relatively low temperature; at the same time, the addition of a toughening agent and a temperature-resistant agent improves the toughness and heat resistance of the bismaleimide resin.

[0026] The preparation method of the hot-melt bismaleimide resin-based prepreg of the present invention controls the content of resin in the prepreg by controlling the surface density of the bismaleimide resin film, so that the resin content in the prepreg is adjustable, and thus it is applicable to different composite material forming processes. The preparation process of the present invention is simple, the resin content in the obtained hot-melt prepreg is stable, the resin is evenly distributed, the volatile content is low, and the prepreg has good draping properties; and the prepared bismaleimide resin-based prepreg is applicable to a variety of composite material forming processes, expanding the application field of the prepreg. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The first aspect of the embodiment of the present invention provides a hot-melt bismaleimide resin matrix, the raw materials for preparing the hot-melt bismaleimide resin matrix include the following components in parts by weight:

[0029] 70-100 parts of bismaleimide resin monomer, 50-65 parts of process modifier, 20-35 parts of active diluent, 10-15 parts of toughening modifier, 10-20 parts of heat-resistant modifier;

[0030] Wherein, the bismaleimide resin monomer is a mixture of one or both of diphenylmethane diamine type bismaleimide monomer and diphenyl ether diamine type bismaleimide monomer.

[0031] The structural formula of the diphenylmethane diamine type bismaleic monomer is shown in the following formula I, and the structural formula of the diphenyl ether diamine type bismaleic monomer is shown in the following formula II.

[0032]

[0033] The present invention adopts two different bismaleimide resin monomers to prepare bismaleimide resin. The two bismaleimide monomers are bismaleimide monomers with good temperature resistance and high adoption rate in the current market. Among them, the temperature resistance of diphenylmethane diamine type bismaleimide monomer is higher than that of diphenylmethane diamine type bismaleimide monomer. The degree of homopolymerization of diphenylmethane diamine type bismaleimide monomer is improved, and the toughness is slightly higher than that of diphenylmethane diamine type bismaleimide monomer. The toughness and temperature resistance of the bismaleimide resin matrix can be adjusted by compounding the two bismaleimide resin monomers. The hot melt bismaleimide resin matrix of the present invention embodiment is added with an active diluent during the synthesis process of the bismaleimide resin, which reduces the viscosity of the bismaleimide resin, so that the bismaleimide resin meets the requirements of hot melt coating at a relatively low temperature; at the same time, the addition of a toughening agent and a temperature resistant agent improves the toughness and heat resistance of the bismaleimide resin.

[0034] In some embodiments, the bismaleimide resin monomer is a mixture of diphenylmethane diamine bismaleimide monomer and diphenyl ether diamine bismaleimide monomer, wherein the mass percentage content of diphenylmethane diamine bismaleimide monomer is 50%-100%, and is not 100%. When the mass percentage content of diphenylmethane diamine bismaleimide monomer is 50%-80%, as the proportion of diphenylmethane diamine bismaleimide monomer increases, the temperature resistance of the bismaleimide resin increases, and the toughness decreases slightly.

[0035] In some embodiments, the process modifier is diallyl bisphenol A; the active diluent is a mixture of toluene and dipropylene phthalate, and the mass ratio of toluene to dipropylene phthalate is 1:0.4-1.6; the toughening modifier is a mixture of one or two of polyaryletherketone and polyimide; the heat-resistant modifier is a mixture of one or two of terminal maleimide branched polysiloxane and aromatic heterocyclic resin. The process modifier uses diallyl bisphenol A (DABPA) to improve the stacking efficiency of the cured product of the bismaleimide resin system. Since DPA can undergo a cross-linking reaction with BMI / DABPA resin, when DPA is used as an active diluent to improve the processing performance of the BMI / DABPA resin system and reduce the viscosity of the resin system, the heat resistance of the resin can be taken into account. Among them, toluene plays the role of a solvent, the reaction system is carried out in a solvent, and the process conditions are relatively mild.

[0036] A second aspect of an embodiment of the present invention provides a method for preparing the above-mentioned hot-melt bismaleimide resin matrix, comprising the following steps:

[0037] S1: Weigh the bismaleimide resin monomer, the process modifier, the reactive diluent, the toughening modifier and the heat-resistant modifier according to their mass fractions;

[0038] S2: mixing the process modifier and the reactive diluent to obtain a mixture;

[0039] S3: adding the bismaleimide resin monomer and the toughening modifier to the mixture, heating, then cooling, removing toluene, and finally adding the heat-resistant modifier, and mixing to obtain the hot-melt bismaleimide resin matrix.

[0040] In some embodiments, in step S2, the process modifier and the reactive diluent are mixed at 30-50° C. for 20-30 min.

[0041] In some embodiments, step S3 specifically includes: adding the bismaleimide resin monomer and the toughening modifier to the mixture, heating to 120-150°C and keeping warm for 1-2 hours, then cooling to 90-110°C, then removing toluene in vacuo, and finally adding the heat-resistant modifier, and blending for 10-30 minutes to obtain the hot-melt bismaleimide resin matrix.

[0042] A third aspect of the embodiments of the present invention provides a hot-melt bismaleimide resin-based prepreg, comprising the hot-melt bismaleimide resin matrix and a reinforcing material.

[0043] A fourth aspect of the embodiments of the present invention provides a method for preparing the above-mentioned hot-melt bismaleimide resin-based prepreg, comprising the following steps:

[0044] A1: Melting the hot-melt bismaleimide resin matrix;

[0045] A2: Use the coating device of the hot melt prepreg machine to coat the molten hot melt bismaleimide resin matrix into a bismaleimide resin film, and control the surface density of the bismaleimide resin film by adjusting the roller gap and coating speed;

[0046] A3: Place reinforcing materials between the bismaleimide resin film layers, use the composite device of the hot melt prepreg machine, and hot-press the bismaleimide resin film and the reinforcing materials through a pressure roller to obtain a hot melt bismaleimide resin-based prepreg.

[0047] The embodiment of the present invention adopts a two-step method to prepare hot melt prepreg, first preparing the film and then preparing the prepreg. Compared with the solution method, the hot melt prepreg prepared by the two-step method has the following advantages: (1) Precise control of the resin content of the prepreg: The thickness of the resin film is controllable, and the thickness of the film is constantly detected by an online thickness gauge during the preparation of the resin film to ensure the consistency of the film thickness, and the resin film and the reinforcement are usually overlapped in a "sandwich" structure, and the resin is melted and embedded into the reinforcement fiber at a high temperature to form a prepreg, so that the resin content in the prepreg can be accurately controlled. (2) Reduce environmental pollution: The hot melt method does not use solvents during the preparation process, which reduces volatiles and environmental pollution, and is beneficial to environmental protection and the health of operators. (3) Reduce porosity: The composite material prepared by the hot melt method has a lower porosity, thereby improving the product quality and mechanical properties of the composite material. (4) Convenient control of the quality of the film: The viscous body or resin film prepared by the resin matrix material can be checked at any time for its gel time, viscosity and other technical indicators to ensure the stability of the quality of the prepreg.

[0048] In some embodiments, step A1 specifically includes: heating the bismaleimide resin at 70-110° C. for 0.5-2 h to melt the bismaleimide resin; in step A2, the surface density of the bismaleimide resin film is controlled at 30-200 g / m 2 , the coating temperature is 70-110°C, and the coating speed is controlled at 2-10 m / min; in step A3, the temperature of the pressing roller is controlled at 80-120°C, the gap between the pressing rollers is controlled at 120-800 μm, and the impregnation speed is controlled at 2-8 m / min. The reinforcing material is a fiber cloth or a unidirectional cloth. The fiber cloth can be a carbon fiber cloth, an organic fiber cloth, an inorganic fiber cloth, or a mixed cloth prepared from inorganic fibers and organic fibers.

[0049] A fifth aspect of the embodiments of the present invention provides a bismaleimide resin-based composite material, which is obtained by curing and molding the above-mentioned hot-melt bismaleimide resin-based prepreg.

[0050] Example 1

[0051] The preparation method of the hot-melt bismaleimide resin matrix of this embodiment comprises the following steps:

[0052] S1: weigh the raw materials according to the ratio;

[0053] S2: 50 kg of diallyl bisphenol A process modifier and 30 kg of active diluent were mixed at 40°C for 25 min, wherein the ratio of toluene to diallyl phthalate in the active diluent was 1:1;

[0054] S3: Add 40kg of diphenylmethane diamine type bismaleimide monomer (I), 40kg of diphenyl ether diamine type bismaleimide monomer (II) and 10kg of polyaryletherketone toughening modifier containing phenolphthalein side groups to the above solution, heat to 130°C and keep warm for 1.5h, then cool to 90°C, remove toluene in vacuo and add 15kg of terminal maleimide branched polysiloxane heat-resistant modifier, and mix for 20min to obtain a hot-melt bismaleimide resin matrix.

[0055] The preparation method of the hot-melt bismaleimide resin-based prepreg of this embodiment comprises the following steps:

[0056] A1: Preheat the bismaleimide resin at 70℃ for 50min to completely melt the bismaleimide resin;

[0057] A2: Use the coating device of the hot melt prepreg machine to coat the BMI resin into a film with uniform thickness, and adjust the film surface density to (60±4) g / m by adjusting the roller gap and coating speed. 2 , the coating temperature is 90℃, and the coating speed is controlled at 3m / min;

[0058] A3: Using the composite device of the hot melt prepreg machine, with the rollers heated, a layer of adhesive film is placed on the top and bottom, and T800-6K grade carbon fiber twill cloth is placed in the middle, and the prepreg is obtained by hot pressing and compounding. The roller temperature is controlled at 105°C, the roller gap is 400μm, and the impregnation speed is controlled at 4m / min.

[0059] Composite material autoclave curing molding process of this embodiment:

[0060] The hot melt prepreg is cut into rectangles by a slitting machine, and the composite blank is prepared by paving; then the surface of the blank is coated with a porous isolation film, a suction felt, and a vacuum bag, and finally placed in a hot press at a temperature not greater than 60°C, and then evacuated, the absolute vacuum degree of the vacuum system is ≤25kPa, and the vacuum degree is maintained for 20min without change; then the temperature is increased to 90°C at a heating rate of 120°C / h, and kept warm for 1h; then the temperature is increased to 120°C at a heating rate of 60°C / h, and kept warm for 0.5h; then the temperature is increased to 180°C at a heating rate of 60°C / h, and the pressure system is 0.6MPa until the curing is completed; then the temperature is increased to 200°C at a heating rate of 60°C / h, and kept warm for 4h; after the curing is completed, the temperature is naturally lowered, and the temperature out of the tank is not greater than 60°C. Finally, the test plate is post-processed, and the post-processing temperature is 230°C and the insulation time is 3h.

[0061] Example 2

[0062] The preparation method of the hot-melt bismaleimide resin matrix of this embodiment comprises the following steps:

[0063] S1: weigh the raw materials according to the ratio;

[0064] S2: 55 kg of diallyl bisphenol A process modifier and 25 kg of active diluent were mixed at 45°C for 20 min, wherein the ratio of toluene to diallyl phthalate in the active diluent was 1:1.2;

[0065] S3: Add 54kg of diphenylmethane diamine type bismaleimide monomer (I), 36kg of diphenyl ether diamine type bismaleimide monomer (II) and 12kg of polyaryletherketone toughening modifier containing phenolphthalein side groups to the above solution, heat to 140°C and keep warm for 1.2h, then cool to 90°C, remove toluene in vacuo and add 15kg of terminal maleimide branched polysiloxane heat-resistant modifier, and blend for 25min to obtain a hot-melt bismaleimide resin matrix.

[0066] The preparation method of the hot-melt bismaleimide resin-based prepreg of this embodiment comprises the following steps:

[0067] A1: Preheat the bismaleimide resin at 90°C for 30 minutes to completely melt the modified bismaleimide resin.

[0068] A2: Use the coating device of the hot melt prepreg machine to coat the modified BMI resin into a film with uniform thickness, and adjust the film surface density to (30±4) g / m by adjusting the roller gap and coating speed. 2 , the coating temperature is 100℃ and the coating speed is controlled at 5m / min.

[0069] A3: The carbon fiber yarn is passed through a porcelain eyelet, a universal comb and a yarn spreading device to spread the carbon fiber yarn so that the carbon fiber surface density is 100g / m2 ;

[0070] A4: Using the composite device of the hot melt prepreg machine, with the rollers heated, a layer of adhesive film is placed on the top and bottom, and a carbon fiber unidirectional cloth is placed in the middle, and the prepreg is obtained by hot pressing and compounding. The roller temperature is controlled at 110°C, the roller gap is controlled at 240μm, and the impregnation speed is controlled at 4m / min.

[0071] The net size forming process of the composite material in this embodiment:

[0072] According to the shape of the net size forming mold, the prepreg is cut and cut by a slitting machine, and the composite blank is prepared by draping. Then the composite blank with the mold is placed on the press; then the temperature is raised to 90℃ at a heating rate of 90℃ / h and kept warm for 1.5h; then the temperature is raised to 120℃ at a heating rate of 30℃ / h and kept warm for 0.5h; then the temperature is raised to 180℃ at a heating rate of 45℃ / h, and the pressure applied to the composite material is calculated to be 0.6MPa until the curing is completed; then the temperature is raised to 200℃ at a heating rate of 60℃ / h and kept warm for 4h; after the curing is completed, the temperature is naturally lowered, and the test plate is taken out when the temperature is not greater than 60℃. Finally, the test plate is post-processed, and the post-processing temperature is 250℃ and the insulation time is 4h.

[0073] Example 3

[0074] The preparation method of the hot-melt bismaleimide resin matrix of this embodiment comprises the following steps:

[0075] S1: weigh the raw materials according to the ratio;

[0076] S2: 50 kg of diallyl bisphenol A process modifier and 30 kg of active diluent were mixed at 45°C for 20 min, wherein the ratio of toluene to diallyl phthalate in the active diluent was 1:0.8;

[0077] S3: Add 60kg of diphenylmethane diamine type bismaleimide monomer (I), 40kg of diphenyl ether diamine type bismaleimide monomer (II) and 10kg of polyimide toughening modifier to the above solution, heat to 140°C and keep warm for 1.2h, then cool to 95°C, remove toluene in vacuo and add 15kg of terminal maleimide branched polysiloxane heat-resistant modifier, and blend for 25min to obtain a hot-melt bismaleimide resin matrix.

[0078] The preparation method of the hot-melt bismaleimide resin-based prepreg of this embodiment comprises the following steps:

[0079] A1: Preheat the bismaleimide resin at 80℃ for 50min to completely melt the bismaleimide resin;

[0080] A2: Use the coating device of the hot melt prepreg machine to coat the BMI resin into a film with uniform thickness, and adjust the film surface density to (50±4) g / m by adjusting the roller gap and coating speed. 2 , the coating temperature is 90℃, and the coating speed is controlled at 3m / min;

[0081] A3: Using the composite device of the hot melt prepreg machine, with the rollers heated, a layer of adhesive film is placed on the top and bottom, and T800-6K grade carbon fiber twill cloth is placed in the middle, and the prepreg is obtained by hot pressing and compounding. The roller temperature is controlled at 105°C, the roller gap is 380μm, and the impregnation speed is controlled at 4m / min.

[0082] Composite material compression molding and curing process of this embodiment:

[0083] The hot melt prepreg is cut into rectangles by a slitting machine, and a composite blank is prepared by draping; then the composite blank is placed on a press; then the temperature is raised to 80°C at a heating rate of 120°C / h and kept at this temperature for 2h; then the temperature is raised to 120°C at a heating rate of 60°C / h and kept at this temperature for 0.5h; then the temperature is raised to 180°C at a heating rate of 60°C / h, and the pressure applied to the composite material is calculated to be 1.0MPa until the curing is completed; then the temperature is raised to 200°C at a heating rate of 60°C / h and kept at this temperature for 4h; after the curing is completed, the temperature is naturally lowered, and the test plate is taken out when the temperature is not greater than 60°C. Finally, the test plate is post-processed at a post-processing temperature of 230°C and a holding time of 4h.

[0084] Example 4

[0085] The preparation method of the hot-melt bismaleimide resin matrix of this embodiment comprises the following steps:

[0086] S1: Weigh the raw materials according to the ratio.

[0087] S2: Mix 60 kg of diallyl bisphenol A process modifier and 35 kg of toluene active diluent at 50 °C for 15 min;

[0088] S3: Add 70kg of diphenylmethane diamine type bismaleimide monomer (I), 30kg of diphenyl ether diamine type bismaleimide monomer (II) and 12kg of polyimide toughening modifier to the above solution, heat to 140°C and keep warm for 1.2h, then cool to 95°C, remove toluene in vacuo and add 15kg of terminal maleimide branched polysiloxane heat-resistant modifier, and blend for 25min to obtain a hot-melt bismaleimide resin matrix.

[0089] The preparation method of the hot-melt bismaleimide resin-based prepreg of this embodiment comprises the following steps:

[0090] A1: Preheat the bismaleimide resin at 80℃ for 50min to completely melt the bismaleimide resin;

[0091] A2: Use the coating device of the hot melt prepreg machine to coat the BMI resin into a film with uniform thickness, and adjust the film surface density to (20±3) g / m by adjusting the roller gap and coating speed. 2 The coating temperature is 95°C and the coating speed is controlled at 5m / min. The carbon fiber yarn is passed through a porcelain eye strip, a universal comb and a yarn spreading device to spread the carbon fiber yarn so that the carbon fiber surface density is 55g / m 2 ;

[0092] A3: Using the composite device of the hot melt prepreg machine, with the rollers heated, a layer of adhesive film is placed on the top and bottom, and a carbon fiber unidirectional cloth is placed in the middle, and the prepreg is obtained by hot pressing and compounding. The roller temperature is controlled at 110°C, the roller gap is controlled at 180μm, and the impregnation speed is controlled at 4m / min.

[0093] Composite material compression molding and curing process of this embodiment:

[0094] The hot melt prepreg is cut into rectangles by a slitting machine, and a composite blank is prepared by draping; then the composite blank is placed on a press; then the temperature is raised to 80°C at a heating rate of 120°C / h and kept at this temperature for 2h; then the temperature is raised to 120°C at a heating rate of 60°C / h and kept at this temperature for 0.5h; then the temperature is raised to 180°C at a heating rate of 60°C / h, and the pressure applied to the composite material is calculated to be 1.0MPa until the curing is completed; then the temperature is raised to 200°C at a heating rate of 60°C / h and kept at this temperature for 4h; after the curing is completed, the temperature is naturally lowered, and the test plate is taken out when the temperature is not greater than 60°C. Finally, the test plate is post-processed at a post-processing temperature of 230°C and a holding time of 4h.

[0095] Example 5

[0096] The preparation method of the hot-melt bismaleimide resin matrix of this embodiment comprises the following steps:

[0097] S1: weigh the raw materials according to the ratio;

[0098] S2: 50 kg of diallyl bisphenol A process modifier and 25 kg of active diluent were mixed at 45°C for 20 min, wherein the ratio of toluene to diallyl phthalate in the active diluent was 1:1;

[0099] S3: Add 72kg of diphenylmethane diamine type bismaleimide monomer (I), 8kg of diphenyl ether diamine type bismaleimide monomer (II) and 10kg of polyimide toughening modifier to the above solution, heat to 150°C and keep warm for 1h, then cool to 95°C, remove toluene in vacuo and add 15kg of terminal maleimide branched polysiloxane heat-resistant modifier, and blend for 25min to obtain a hot-melt bismaleimide resin matrix.

[0100] The preparation method of the hot-melt bismaleimide resin-based prepreg of this embodiment comprises the following steps:

[0101] A1: Preheat the bismaleimide resin at 80°C for 50 minutes to completely melt the bismaleimide resin.

[0102] A2: Use the coating device of the hot melt prepreg machine to coat the BMI resin into a film with uniform thickness, and adjust the film surface density to (50±4) g / m by adjusting the roller gap and coating speed. 2 , the coating temperature is 90℃ and the coating speed is controlled at 3m / min.

[0103] A3: Using the composite device of the hot melt prepreg machine, with the rollers heated, a layer of adhesive film is placed on the top and bottom, and T800-6K grade carbon fiber twill cloth is placed in the middle, and the prepreg is obtained by hot pressing and compounding. The roller temperature is controlled at 105°C, the roller gap is 380μm, and the impregnation speed is controlled at 4m / min.

[0104] Composite material compression molding and curing process of this embodiment:

[0105] The hot melt prepreg is cut into rectangles by a slitting machine, and a composite blank is prepared by draping; then the composite blank is placed on a press; then the temperature is raised to 90°C at a heating rate of 120°C / h and kept warm for 1.5h; then the temperature is raised to 120°C at a heating rate of 60°C / h and kept warm for 0.5h; then the temperature is raised to 180°C at a heating rate of 60°C / h, and the pressure applied to the composite material is calculated to be 0.8MPa until the curing is completed; then the temperature is raised to 200°C at a heating rate of 60°C / h and kept warm for 4h; after the curing is completed, the temperature is naturally lowered, and the test plate is taken out when the temperature is not greater than 60°C. Finally, the test plate is post-processed, and the post-processing temperature is 230°C and the insulation time is 4h.

[0106] Comparative Example 1

[0107] The difference between this comparative example and Example 1 is that in step S3, a single diphenylmethane diamine type bismaleic acid monomer is used as a monomer of the bismaleic acid resin matrix, and no diphenyl ether diamine type bismaleic acid monomer is added.

[0108] Comparative Example 2

[0109] The difference between this comparative example and Example 1 is that in step S3, a single diphenyl ether diamine type bismaleic acid monomer is used as a monomer of the bismaleic acid resin matrix, and no diphenylmethane diamine type bismaleic acid monomer is added.

[0110] Table 1 Tensile strength test of hot melt bismaleimide resin composites

[0111]

[0112] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A hot melt bismaleimide resin matrix, characterized in that: The raw materials for its preparation include the following components in parts by weight: 70-100 parts of bismaleimide resin monomer, 50-65 parts of process modifier, 20-35 parts of active diluent, 10-15 parts of toughening modifier, 10-20 parts of heat-resistant modifier; Wherein, the bismaleimide resin monomer is a mixture of one or both of diphenylmethane diamine type bismaleimide monomer and diphenyl ether diamine type bismaleimide monomer.

2. The hot-melt bismaleimide resin matrix according to claim 1, characterized in that: The bismaleimide resin monomer is a mixture of diphenylmethane diamine type bismaleimide monomer and diphenyl ether diamine type bismaleimide monomer, wherein the mass percentage content of the diphenylmethane diamine type bismaleimide monomer is 50%-100%, and is not 100%.

3. The hot-melt bismaleimide resin matrix according to claim 1, characterized in that: The process modifier is diallyl bisphenol A; The active diluent is a mixture of toluene and dipropylene phthalate, and the mass ratio of toluene to dipropylene phthalate is 1:0.4-1.6; The toughening modifier is one of polyaryletherketone and polyimide or a mixture of the two; The heat-resistant modifier is one of maleimide-terminated branched polysiloxane and aromatic heterocyclic resin or a mixture of both.

4. A method for preparing a hot-melt bismaleimide resin matrix as claimed in any one of claims 1 to 3, characterized in that: The steps include: S1: Weigh the bismaleimide resin monomer, the process modifier, the reactive diluent, the toughening modifier and the heat-resistant modifier according to their mass fractions; S2: mixing the process modifier and the reactive diluent to obtain a mixture; S3: adding the bismaleimide resin monomer and the toughening modifier to the mixture, heating, then cooling, removing toluene, and finally adding the heat-resistant modifier, and mixing to obtain the hot-melt bismaleimide resin matrix.

5. The method for preparing a hot-melt bismaleimide resin matrix according to claim 4, characterized in that: In step S2, the process modifier and the reactive diluent are mixed at 30 to 50° C. for 20 to 30 minutes.

6. The method for preparing a hot-melt bismaleimide resin matrix according to claim 4, characterized in that: Step S3 specifically includes: adding the bismaleimide resin monomer and the toughening modifier to the mixture, heating to 120-150°C and keeping warm for 1-2 hours, then cooling to 90-110°C, then removing toluene in vacuo, and finally adding the heat-resistant modifier, and blending for 10-30 minutes to obtain the hot-melt bismaleimide resin matrix.

7. A hot melt bismaleimide resin-based prepreg, characterized in that: The invention comprises a hot-melt bismaleimide resin matrix and a reinforcing material as described in any one of claims 1 to 3.

8. A method for preparing a hot-melt bismaleimide resin-based prepreg as claimed in claim 7, characterized in that: The steps include: A1: Melting the hot-melt bismaleimide resin matrix; A2: Use the coating device of the hot melt prepreg machine to coat the molten hot melt bismaleimide resin matrix into a bismaleimide resin film, and control the surface density of the bismaleimide resin film by adjusting the roller gap and coating speed; A3: Place reinforcing materials between the bismaleimide resin film layers, use the composite device of the hot melt prepreg machine, and hot-press the bismaleimide resin film and the reinforcing materials through a pressure roller to obtain a hot melt bismaleimide resin-based prepreg.

9. The method for preparing a hot-melt bismaleimide resin-based prepreg according to claim 8, characterized in that: Step A1 specifically comprises: heating the bismaleimide resin at a temperature of 70 to 110° C. for 0.5 to 2 hours to melt the bismaleimide resin; In step A2, the surface density of the bismaleimide resin film is controlled at 30 to 200 g / m 2 , the coating temperature is 70~110℃, and the coating speed is controlled at 2~10m / min; In step A3, the temperature of the pressing roller is controlled at 80-120° C., the gap between the pressing rollers is controlled at 120-800 μm, and the impregnation speed is controlled at 2-8 m / min.

10. A bismaleimide resin-based composite material, characterized in that: The hot-melt bismaleimide resin-based prepreg as claimed in claim 7 is cured and molded to obtain the same.

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