A hot-melt bis-maleimide resin matrix, prepreg, composite material and preparation method thereof

Abstract

The present invention provides a hot-melt bis-maleimide resin matrix, prepreg, composite material and preparation method thereof. The hot-melt bis-maleimide resin matrix is characterized in that its preparation raw materials include the following components in parts by mass: 70-100 parts of bis-maleimide resin monomer, 50-65 parts of process modifier, 20-35 parts of reactive diluent, 10-15 parts of toughening modifier, and 10-20 parts of heat resistance modifier; wherein, the bis-maleimide resin monomer is one or a mixture of two of diphenylmethane diamine type bis-maleimide monomer and diphenyl ether diamine type bis-maleimide monomer. The hot-melt bis-maleimide resin prepreg prepared by this method has stable resin content, uniform resin distribution, low volatile content, and good drapability of the prepreg; and the prepared bis-maleimide based prepreg is applicable to a variety of composite material forming processes, expanding the application field of the prepreg.

Description

Technical Field

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

[0002] With the continuous development of aerospace weaponry and equipment, further requirements are put forward for the heat resistance and mechanical properties of structural composite materials. Carbon fiber / epoxy composite materials can no longer meet the high-temperature resistance requirements. Bis-maleimide 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 components in aviation and aerospace. Chinese patent document with publication number CN116426123A discloses a bis-maleimide resin composition, composite material and a preparation method thereof. The bis-maleimide resin composition comprises the following components in parts by mass: 100 parts of bis-maleimide resin, 30 - 50 parts of allyl phenoxy resin, and 20 - 45 parts of diallyl bisphenol A; the preparation raw materials of the allyl phenoxy resin include diallyl phenol, flexible side-chain modified epoxy resin, and a 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 this bis-maleimide resin composition, the allyl groups in the bis-maleimide resin react with the active C=C on the ring of the allyl phenoxy resin and diallyl bisphenol A to form a tough resin with a highly crosslinked ring structure, improving the toughness of the bis-maleimide resin. And by introducing flexible chain segments into the bis-maleimide resin through the allyl phenoxy resin, the toughness of the bis-maleimide resin is further improved, and at the same time, the impact resistance of the bis-maleimide resin is improved. However, the existing bis-maleimide resins currently have disadvantages such as high melting point, poor solubility, high molding temperature, large brittleness of the cured product, and insufficient toughness and heat resistance, which limit their application scope.

[0003] There are two common prepreg forming methods, the solution method and the hot-melt method. The solution method is a process in which the fabric is impregnated with a resin solution, and then the solvent is volatilized to make the prepreg reach 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 bis-maleimide resin with stronger toughness and heat resistance, and a preparation method of a bis-maleimide resin-based prepreg that can accurately control the resin content in the prepreg and has a low volatile content. Summary of the Invention

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

[0006] To solve the above problems, the first aspect of the present invention provides a hot-melt bis-maleimide resin matrix, and the raw materials for its preparation include the following components in parts by mass:

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

[0008] Among them, the bis-maleimide resin monomer is one or a mixture of two of diphenylmethane diamine type bis-maleimide monomer and diphenyl ether diamine type bis-maleimide monomer.

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

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

[0011] The second aspect of the present invention provides a preparation method of the above hot-melt bis-maleimide resin matrix, including the following steps:

[0012] S1: Weigh the bis-maleimide resin monomer, the process modifier, the reactive diluent, the toughening modifier and the heat-resistant modifier according to the parts by mass.

[0013] S2: Mix the process modifier and the reactive diluent to obtain a mixture.

[0014] S3: Add the bis-maleimide resin monomer and the toughening modifier into the mixture, heat, then cool down, remove toluene, and finally add the heat-resistant modifier, and mix to obtain the hot-melt bis-maleimide resin matrix.

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

[0016] Preferably, step S3 specifically includes: adding the bis-maleimide resin monomer and the toughening modifier into the mixture, heating up to 120-150°C and holding for 1-2 h, then cooling down to 90-110°C, then removing toluene under vacuum, and finally adding the heat-resistant modifier, and blending for 10-30 min to obtain the hot-melt bis-maleimide resin matrix.

[0017] The third aspect of the present invention provides a hot-melt bis-maleimide resin-based prepreg, which comprises the above-mentioned hot-melt bis-maleimide resin matrix and reinforcing material.

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

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

[0020] A2: Using the coating device of a hot-melt prepreg machine to coat the melted hot-melt bis-maleimide resin matrix into a bis-maleimide resin film, and controlling the areal density of the bis-maleimide resin film by adjusting the roller gap and coating speed;

[0021] A3: Placing the reinforcing material between the layers of the bis-maleimide resin film, and using the composite device of the hot-melt prepreg machine to thermocompression laminate the bis-maleimide resin film and the reinforcing material through a pressure roller to obtain the hot-melt bis-maleimide resin-based prepreg.

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

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

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

[0025] In the preparation method of the hot-melt bis-maleimide resin matrix of the present invention, an active diluent is added during the synthesis of the bis-maleimide resin, which reduces the viscosity of the bis-maleimide resin, enabling the bis-maleimide resin to meet the requirements of hot-melt coating at a lower temperature; meanwhile, the addition of a toughening agent and a heat-resistant agent improves the toughness and heat resistance of the bis-maleimide resin.

[0026] In the preparation method of the hot-melt bis-maleimide resin-based prepreg of the present invention, the resin content in the prepreg is controlled by controlling the areal density of the bis-maleimide resin film, so that the resin content in the prepreg is adjustable, thereby being applicable to different composite material molding processes. The preparation process of the present invention is simple, the resin content in the obtained hot-melt prepreg is stable, the resin distribution is uniform, the volatile content is low, and the laying property of the prepreg is good; moreover, the prepared bis-maleimide resin-based prepreg is applicable to a variety of composite material molding processes, expanding the application field of the prepreg. Detailed implementation manners

[0027] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The first aspect of the embodiments of the present invention provides a hot-melt bis-maleimide resin matrix, and its preparation raw materials include the following components in parts by mass:

[0029] 70-100 parts of bis-maleimide 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] Among them, the bis-maleimide resin monomer is one or a mixture of two of diphenylmethane diamine type bis-maleimide monomer and diphenyl ether diamine type bis-maleimide monomer.

[0031] Among them, the structural formula of the diphenylmethane diamine type bis-maleimide monomer is shown as formula Ⅰ below, and the structural formula of the diphenyl ether diamine type bis-maleimide monomer is shown as formula Ⅱ below.

[0032]

[0033] The present invention uses two different bis-maleimide resin monomers to prepare bis-maleimide resin. The two bis-maleimide monomers are bis-maleimide monomers with better heat resistance and higher adoption rate in the current market. Among them, the heat resistance of the diphenylmethane diamine type bis-maleimide monomer is higher than that of the diphenyl ether diamine type bis-maleimide monomer. The degree of homopolymerization of the diphenyl ether diamine type bis-maleimide monomer is improved, and the toughness is slightly higher than that of the diphenylmethane diamine type bis-maleimide monomer. By compounding the two bis-maleimide resin monomers, the toughness and heat resistance of the bis-maleimide resin matrix can be regulated. In the hot-melt bis-maleimide resin matrix of the embodiments of the present invention, an active diluent is added during the synthesis of the bis-maleimide resin, which reduces the viscosity of the bis-maleimide resin, enabling the bis-maleimide resin to meet the requirements of hot-melt coating film at a lower temperature; at the same time, the addition of a toughening agent and a heat-resistant agent improves the toughness and heat resistance of the bis-maleimide resin.

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

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

[0036] The second aspect of the embodiments of the present invention provides a preparation method of the above-mentioned hot-melt bismaleimide resin matrix, including 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 parts by mass;

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

[0039] S3: Add the bismaleimide resin monomer and the toughening modifier to the mixture, heat, then cool down, remove toluene, and finally add the heat-resistant modifier, and obtain the hot-melt bismaleimide resin matrix after mixing.

[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 up to 120 - 150 °C and holding for 1 - 2 h, then cooling down to 90 - 110 °C, then removing toluene under vacuum, and finally adding the heat-resistant modifier, and obtaining the hot-melt bismaleimide resin matrix after blending for 10 - 30 min.

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

[0043] The fourth aspect of the embodiments of the present invention provides a preparation method of the above-mentioned hot-melt bismaleimide resin-based prepreg, including the following steps:

[0044] A1: Melt the hot-melt bis-maleimide resin matrix;

[0045] A2: Using the film coating device of a hot-melt prepreg machine, coat the melted hot-melt bis-maleimide resin matrix into a bis-maleimide resin film, and control the areal density of the bis-maleimide resin film by adjusting the roller gap and film coating speed;

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

[0047] In the embodiment of the present invention, a two-step method is adopted to prepare the hot-melt prepreg. First, the film is prepared, and then the prepreg is prepared. Compared with the solution method, the hot-melt prepreg prepared by the two-step method has the following advantages: (1) The resin content of the prepreg is accurately controlled: the thickness of the resin film is controllable, and during the preparation process of the resin film, the film thickness is detected in real time by an on-line thickness gauge to ensure the consistency of the film thickness. And the resin film and the reinforcement are usually laminated in a "sandwich" structure, and the resin is melted and embedded into the reinforcement fibers at high temperature to form a prepreg. Therefore, 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, reducing volatile components and environmental pollution, which is beneficial to environmental protection and the health of operators. (3) Reduce the 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) Facilitate the control of the film quality: The technical indicators such as the gel time and viscosity of the viscous body or resin film prepared from the resin matrix material can be checked at any time to ensure the stable quality of the prepreg.

[0048] In some embodiments, step A1 specifically includes: heating the bis-maleimide resin at a temperature of 70 - 110°C for 0.5 - 2 h to melt the bis-maleimide resin; in step A2, the areal density of the bis-maleimide resin film is controlled to be 30 - 200 g / m 2 , the film coating temperature is 70 - 110°C, and the film covering speed is controlled at 2 - 10 m / min; in step A3, the temperature of the pressure roller is controlled at 80 - 120°C, the pressure roller gap 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. Among them, the fiber cloth can be a carbon fiber cloth, an organic fiber cloth, an inorganic fiber cloth, or a mixed woven cloth prepared from inorganic fibers and organic fibers.

[0049] The fifth aspect of the embodiment of the present invention provides a bis-maleimide resin matrix composite material, which is obtained after curing and forming using the above-mentioned hot-melt bis-maleimide resin matrix prepreg.

[0050] Example 1

[0051] The preparation method of the hot-melt bis-maleimide resin matrix in this embodiment includes the following steps:

[0052] S1: Weigh raw materials according to the ratio.

[0053] S2: Mix 50 kg of diallylbisphenol A process modifier and 30 kg of reactive diluent at 40 °C for 25 min, where the ratio of toluene and diallyl phthalate in the reactive diluent is 1:1.

[0054] S3: Add 40 kg of diphenylmethane diamine type bis-maleimide monomer (I), 40 kg of diphenyl ether diamine type bis-maleimide monomer (II), and 10 kg of phthalophenone-containing polyaryletherketone toughening modifier to the above solution. After heating up to 130 °C and holding for 1.5 h, cool down to 90 °C, remove toluene under vacuum, and add 15 kg of terminal maleimide-branched polysiloxane heat-resistant modifier. After blending for 20 min, a hot-melt bis-maleimide resin matrix is obtained.

[0055] The preparation method of the hot-melt bis-maleimide resin matrix prepreg in this embodiment includes the following steps:

[0056] A1: Preheat the bis-maleimide resin at 70 °C for 50 min to completely melt the bis-maleimide resin.

[0057] A2: Use the film coating device of the hot-melt prepreg machine to coat the bis-maleimide resin into a film with a uniform thickness, and adjust the areal density of the film to (60 ± 4) g / m 2 , the film coating temperature is 90 °C, and the film laminating speed is controlled at 3 m / min.

[0058] A3: Use the composite device of the hot-melt prepreg machine. Under the condition of heating the pressure roller, place a film on each of the upper and lower sides, place a T800-6K grade carbon fiber twill cloth in the middle, and perform hot pressing and compounding to obtain the prepreg. The temperature of the pressure roller is controlled at 105 °C, the gap of the pressure roller is 400 μm, and the impregnation speed is controlled at 4 m / min.

[0059] The hot press autoclave curing and forming process of the composite material in this embodiment:

[0060] The hot-melt prepreg is cut into rectangles by a slitter, and a composite blank is prepared by a laying method; then a porous separator film, a bleed felt, and a vacuum bag are coated on the surface of the blank, and finally it is placed in a autoclave at a temperature not higher than 60 °C, and then evacuated. The absolute vacuum degree of the vacuum system is ≤25 kPa, and the vacuum degree remains unchanged for 20 min; then it is heated to 90 °C at a heating rate of 120 °C / h and held for 1 h; then it is heated to 120 °C at a heating rate of 60 °C / h and held for 0.5 h; then it is heated to 180 °C at a heating rate of 60 °C / h, and the pressure system is 0.6 MPa until the curing is completed; then it is heated to 200 °C at a heating rate of 60 °C / h and held for 4 h; after curing, it is cooled naturally, and the out-of-autoclave temperature is not higher than 60 °C. Finally, the test plate is post-treated, the post-treatment temperature is 230 °C, and the holding time is 3 h.

[0061] Example 2

[0062] The preparation method of the hot-melt bis-maleimide resin matrix in this example includes the following steps:

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

[0064] S2: Mix 55 kg of diallylbisphenol A process modifier and 25 kg of reactive diluent at 45 °C for 20 min, and the ratio of toluene and diallyl phthalate in the reactive diluent is 1:1.2;

[0065] S3: Add 54 kg of diphenylmethane diamine type bis-maleimide monomer (I), 36 kg of diphenyl ether diamine type bis-maleimide monomer (II), and 12 kg of phthalophenone side group-containing polyaryletherketone toughening modifier to the above solution, heat up to 140 °C and hold for 1.2 h, then cool down to 90 °C, remove toluene under vacuum and add 15 kg of terminal maleimide-branched polysiloxane heat-resistant modifier, and obtain the hot-melt bis-maleimide resin matrix after blending for 25 min.

[0066] The preparation method of the hot-melt bis-maleimide resin matrix prepreg in this example includes the following steps:

[0067] A1: Preheat the bis-maleimide resin at 90 °C for 30 min to completely melt the modified bis-maleimide resin.

[0068] A2: Using the coating device of a hot-melt prepreg machine, coat the modified bis-maleimide resin into a film with a uniform thickness, and adjust the areal density of the film to (30 ± 4) g / m 2 , the coating temperature is 100 °C, and the film laminating speed is controlled at 5 m / min.

[0069] A3: Pass the carbon fiber yarn through porcelain eye bars, a universal comb, and a yarn spreading device to spread the carbon fiber yarn, so that the areal density of the carbon fiber is 100 g / m2 ;

[0070] A4: The composite device using a hot melt prepreg machine. With the pressure rollers heated, one layer of adhesive film is placed on each of the upper and lower sides, and a unidirectional carbon fiber fabric is in the middle. The prepreg is obtained through hot pressing and compounding. The temperature of the pressure rollers is controlled at 110°C, the gap between the pressure rollers is controlled at 240 μm, and the impregnation speed is controlled at 4 m / 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 typed by a slitter, and a composite material blank is prepared by the laying method. Then the composite material blank with the mold is placed on a press; then it is heated to 90°C at a heating rate of 90°C / h and held for 1.5 h; then it is heated to 120°C at a heating rate of 30°C / h and held for 0.5 h; then it is heated to 180°C at a heating rate of 45°C / h, and the pressure applied to the composite material is calculated to be 0.6 MPa until the curing is completed; then it is heated to 200°C at a heating rate of 60°C / h and held for 4 h; after the curing is completed, it is cooled naturally, and the test plate is taken out when the temperature is not higher than 60°C. Finally, the test plate is post-treated, the post-treatment temperature is 250°C, and the holding time is 4 h.

[0073] Example 3

[0074] The preparation method of the hot melt bis - maleimide resin matrix in this embodiment includes the following steps:

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

[0076] S2: Mix 50 kg of diallylbisphenol A process modifier and 30 kg of reactive diluent at 45°C for 20 min. The ratio of toluene and diallyl phthalate in the reactive diluent is 1:0.8;

[0077] S3: Add 60 kg of diphenylmethane diamine type bis - maleimide monomer (Ⅰ), 40 kg of diphenyl ether diamine type bis - maleimide monomer (Ⅱ), and 10 kg of polyimide toughening modifier to the above solution. Heat it up to 140°C and hold for 1.2 h, then cool it down to 95°C, remove toluene under vacuum, and add 15 kg of terminal maleimide - branched polysiloxane heat - resistant modifier. After blending for 25 min, the hot melt bis - maleimide resin matrix is obtained.

[0078] The preparation method of the hot melt bis - maleimide resin - based prepreg in this embodiment includes the following steps:

[0079] A1: Preheat the bis - maleimide resin at 80°C for 50 min to make the bis - maleimide resin completely molten;

[0080] A2: The film coating device of the hot-melt prepreg machine is used to coat the bismaleimide resin into a film with uniform thickness, and by adjusting the roller gap and the film coating speed, the areal density of the film is adjusted to be (50±4) g / m 2 , the film coating temperature is 90 °C, and the film laminating speed is controlled at 3 m / min;

[0081] A3: The composite device of the hot-melt prepreg machine is used. Under the condition of heating the pressure roller, one layer of film is placed on each of the upper and lower sides, and the T800-6K grade carbon fiber twill cloth is placed in the middle. The prepreg is obtained by hot pressing and compounding. The temperature of the pressure roller is controlled at 105 °C, the gap of the pressure roller is 380 μm, and the impregnation speed is controlled at 4 m / min.

[0082] The composite material molding and curing process of this embodiment:

[0083] The hot-melt prepreg is cut into rectangles by a slitter, and the composite material blank is prepared by the laying method; then the composite material blank is placed on the press; then it is heated to 80 °C at a heating rate of 120 °C / h and kept warm for 2 h; then it is heated to 120 °C at a heating rate of 60 °C / h and kept warm for 0.5 h; then it is heated to 180 °C at a heating rate of 60 °C / h, and the pressure applied to the composite material is calculated to be 1.0 MPa until the curing is completed; then it is heated to 200 °C at a heating rate of 60 °C / h and kept warm for 4 h; after the curing is completed, it is cooled naturally, and the test plate is taken out when the temperature is not higher than 60 °C. Finally, the test plate is post-treated, the post-treatment temperature is 230 °C, and the holding time is 4 h.

[0084] Example 4

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

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

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

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

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

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

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

[0092] A3: The composite device of the hot melt prepreg machine is used. Under the condition of heating the pressure roller, one layer of film is placed on each of the upper and lower sides, and a carbon fiber unidirectional cloth is in the middle. The prepreg is obtained by hot pressing and compounding. The temperature of the pressure roller is controlled at 110°C, the gap of the pressure roller is controlled at 180 μm, and the impregnation speed is controlled at 4 m / min.

[0093] The composite material molding and curing process of this embodiment:

[0094] The hot melt prepreg is cut into rectangles by a slitter, and the composite material blank is prepared by the laying method; then the composite material blank is placed on a press; then it is heated to 80°C at a heating rate of 120°C / h and kept warm for 2 h; then it is heated to 120°C at a heating rate of 60°C / h and kept warm for 0.5 h; then it is heated to 180°C at a heating rate of 60°C / h, and by calculation, the pressure applied to the composite material is 1.0 MPa until the curing is completed; then it is heated to 200°C at a heating rate of 60°C / h and kept warm for 4 h; after the curing is completed, it is cooled naturally, and the test plate is taken out when the temperature is not higher than 60°C. Finally, the test plate is post-treated, the post-treatment temperature is 230°C, and the holding time is 4 h.

[0095] Example 5

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

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

[0098] S2: 50 kg of diallylbisphenol A process modifier and 25 kg of reactive diluent are mixed at 45°C for 20 min, and the ratio of toluene and diallyl phthalate in the reactive diluent is 1:1;

[0099] S3: 72 kg of diphenylmethane diamine type bismaleimide monomer (I), 8 kg of diphenyl ether diamine type bismaleimide monomer (II) and 10 kg of polyimide toughening modifier are added to the above solution. After heating and rising to 150°C and keeping warm for 1 h, it is cooled to 95°C, toluene is removed under vacuum, and 15 kg of terminal maleimide branched polysiloxane heat-resistant modifier is added. After blending for 25 min, the hot melt bismaleimide resin matrix is obtained.

[0100] The preparation method of the hot-melt bis-maleimide resin-based prepreg in this embodiment includes the following steps:

[0101] A1: Preheat the bis-maleimide resin at 80 °C for 50 min to completely melt the bis-maleimide resin.

[0102] A2: Using the film coating device of the hot-melt prepreg machine, coat the bis-maleimide resin into a film with a uniform thickness, and adjust the areal density of the film to (50 ± 4) g / m 2 , the film coating temperature is 90 °C, and the film laminating speed is controlled at 3 m / min.

[0103] A3: Using the composite device of the hot-melt prepreg machine, place a film on each of the upper and lower sides and place a T800-6K grade carbon fiber twill fabric in the middle under the condition of heating the pressure roller, and obtain the prepreg by hot pressing and composite, the temperature of the pressure roller is controlled at 105 °C, the gap of the pressure roller is 380 μm, and the impregnation speed is controlled at 4 m / min.

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

[0105] Cut the hot-melt prepreg into rectangles by a slitter, and prepare the composite material blank by the laying method; then place the composite material blank on the press; then heat it to 90 °C at a heating rate of 120 °C / h and keep it warm for 1.5 h; then heat it to 120 °C at a heating rate of 60 °C / h and keep it warm for 0.5 h; then heat it to 180 °C at a heating rate of 60 °C / h, and make the pressure applied to the composite material be 0.8 MPa through calculation until the curing is completed; then heat it to 200 °C at a heating rate of 60 °C / h and keep it warm for 4 h; after the curing is completed, cool it naturally, and take out the test plate when the temperature is not higher than 60 °C. Finally, perform post-treatment on the test plate, the post-treatment temperature is 230 °C, and the holding time is 4 h.

[0106] Comparative Example 1

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

[0110] Table 1 Tensile strength test of hot-melt bis-maleimide resin composite material

[0111]

[0112] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or alterations derived therefrom still fall within the protection scope of the present 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 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%; 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 maleimide-terminated branched polysiloxane.

2. A method for preparing a hot-melt bismaleimide resin matrix as claimed in claim 1, 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.

3. The method for preparing a hot-melt bismaleimide resin matrix according to claim 2, 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.

4. The method for preparing a hot-melt bismaleimide resin matrix according to claim 2, 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.

5. A hot melt bismaleimide resin-based prepreg, characterized in that: It comprises the hot-melt bismaleimide resin matrix and reinforcing material as described in claim 1.

6. A method for preparing a hot-melt bismaleimide resin-based prepreg as claimed in claim 5, 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.

7. The method for preparing a hot-melt bismaleimide resin-based prepreg according to claim 6, 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.

8. A bismaleimide resin-based composite material, characterized in that: The hot-melt bismaleimide resin-based prepreg as claimed in claim 5 is cured and molded to obtain the same.

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