A high-tg modified high-modulus bismaleimide resin composition, a preparation method thereof, a prepreg and application thereof

Abstract

The present application relates to a kind of high Tg modified high modulus bismaleimide resin composition and its preparation method, prepreg and application, the bismaleimide resin composition includes: 5-10 parts of bisphenol A double allyl ether, 50-80 parts of bismaleimide resin, 5-20 parts of cyanate resin, 5-15 parts of epoxy resin;The molecular main chain of the bismaleimide resin includes aromatic ring or biphenyl structure;The epoxy resin includes multiple continuous aromatic heterocyclic epoxy resin, phenol biphenyl type epoxy resin or triphenylmethane type epoxy resin.Aiming at the problem that the Tg of existing conventional bismaleimide prepreg system is generally limited to below 350 DEG C, due to the establishment of bismale-imide-triazine-oxazoline ketone full interpenetrating polymer network, the crosslinking density reaches the extreme, the glass transition temperature of system is stably jumped to above 387 DEG C (the physical extreme deduction is more than 390 DEG C), thereby having the ability of long-term safe bearing under the harsh thermodynamic environment of more than 350 DEG C.

Description

Technical Field

[0001] This invention relates to carbon fiber reinforced bismaleimide resin formulation systems, and more particularly to a high Tg modified high modulus bismaleimide resin composition, its preparation method, prepreg, and applications. Background Technology

[0002] Bismaleimide (BMI)-based carbon fiber composites are widely used in aerospace high-temperature structural components due to their excellent mechanical strength, modulus, and high-temperature resistance. However, the glass transition temperature (Tg) of conventional BMI prepreg systems is generally below 350°C, making them unsuitable for use in extreme environments above 350°C. Current applications exceeding 350°C often rely on expensive polyimide (PI) systems. However, polyimide systems typically contain solvents, and the curing process requires significant venting, which can easily lead to defects such as pores within the cured components, posing a significant risk to the long-term safe operation of high-temperature structural components. Therefore, if the Tg of BMI prepreg could be increased to the same level as polyimide (Tg > 380°C), it would not only meet the extreme operating requirements above 350°C but also completely eliminate the internal defects caused by curing venting in polyimide prepregs, significantly reducing component manufacturing costs.

[0003] U.S. Patent Application Publication No. WO2025123873A1 discloses a modified bismaleimide prepolymer. By using a naphthalene-containing modifier to modify the bismaleimide resin, the resulting modified bismaleimide prepolymer, due to the presence of two or more naphthalene rings in its structure, exhibits a low coefficient of thermal expansion, excellent high-temperature modulus retention, and extremely high heat resistance in its cured product. Furthermore, by rationally combining the above-mentioned modified bismaleimide prepolymer with other raw material components, a resin composition with a low coefficient of thermal expansion, excellent high-temperature modulus retention, and extremely high heat resistance can be prepared without adding a large proportion of inorganic fillers, avoiding the dispersibility and processability problems caused by adding large amounts of inorganic fillers. However, this formulation system is used for semiconductor packaging thin film materials, which are not composite material systems. Its formulation is generally solid, requiring the addition of various organic solvents during film preparation, and cannot be directly used as a semi-solid resin for prepreg applications.

[0004] Chinese patent CN107523055B discloses a high-temperature resistant alkynyl monomaleimide-modified bismaleimide resin and its preparation method. The high-temperature resistant alkynyl monomaleimide-modified bismaleimide resin is prepared from bismaleimide, m-ethynylphenylmaleimide resin, diallylphenyl compound, organic toughening agent, and inorganic filler modifier. The method includes: 1. Weighing; 2. Preparing a bismaleimide prepolymer; 3. Preparing an alkynyl-modified bismaleimide resin; 4. Adding the organic toughening agent and inorganic filler modifier to the alkynyl-modified bismaleimide resin and stirring evenly to obtain the high-temperature resistant alkynyl monomaleimide-modified bismaleimide resin. This method only increases the network density by modifying the bismaleimide resin to increase the crosslinking density of the bismaleimide double bond reaction; the Tg and modulus still need further improvement. Summary of the Invention

[0005] This invention aims to provide a high-Tg modified high-modulus bismaleimide resin composition, its preparation method, prepreg, and application, solving the problems of insufficient heat resistance upper limit and low high-temperature mechanical retention rate of bismaleimide resin systems in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high Tg modified high modulus bismaleimide resin composition comprises the following raw materials in parts by weight: 5-10 parts bisphenol A dielyl ether, 50-80 parts bismaleimide resin, 5-20 parts cyanate ester resin, and 5-15 parts epoxy resin. The main molecular chain of the bismaleimide resin contains an aromatic ring or a biphenyl structure. The epoxy resin includes multiple continuous aromatic heterocyclic epoxy resins, phenol-biphenyl type epoxy resins, or triphenylmethane type epoxy resins.

[0007] This invention is the first to propose a specific quaternary resin composition formulation that combines ultra-high Tg and high toughness. The ingenuity of the formulation design lies in breaking with convention by using bisphenol A dielyl ether (DABPA) as a multi-effect additive that combines the latent curing properties of the Claisen rearrangement with the pure physical dilution effect; at the same time, it is necessary to use a special high-rigidity epoxy resin containing multiple aromatic heterocycles, biphenyl structures, or triphenylmethane (TPM) structures, rather than commercially available ordinary epoxy resins.

[0008] Preferably, a high-Tg modified high-modulus bismaleimide resin composition comprises the following raw materials in parts by weight: 5-7 parts bisphenol A dielyl ether, 50-70 parts bismaleimide resin, 5-10 parts cyanate ester resin, and 5-7 parts epoxy resin. This high-Tg modified high-modulus bismaleimide resin composition within this range of parts by weight exhibits higher room temperature flexural strength and 350°C flexural strength, room temperature flexural modulus and 350°C flexural modulus, and a moderate viscosity range.

[0009] The ratio of cyanate ester and epoxy resin used in this invention is also a preferred ratio. Exceeding or missing these ratios will affect the overall effect (see Comparative Examples 1, 2 and 6, 7 of this application).

[0010] According to embodiments of the present invention, the present invention can be further optimized, and the optimized technical solution is as follows: The cyanate resin includes one or more of bisphenol A cyanate, bisphenol F cyanate, bisphenol M cyanate, dicyclopentadiene cyanate, and bisphenol E cyanate.

[0011] In one preferred embodiment, the bismaleimide resin is selected from one or more of BMI-1000, BMI-2300, BMI-4000, BMI-5100, BMI-600, and BMI-700.

[0012] In one preferred embodiment, the phenol-biphenyl type epoxy resin is selected from one or more of Jinan Shengquan SQXN-321, SQXN-322, SQXN-323, and SQXN-324.

[0013] In one preferred embodiment, the triphenylmethane-type epoxy resin is selected from one or more of Jinan Shengquan SQTN-331, SQTN-332, and SQTN-333.

[0014] This invention also discloses a method for preparing the high Tg modified high modulus bismaleimide resin composition, comprising the following steps: S1. Disperse 5-10 parts of bisphenol A dielyl ether evenly and heat to 100-120℃, then add 5-15 parts of epoxy resin and 5-20 parts of cyanate ester resin, and continue stirring to fully dissolve the solid resin to obtain a mixture. S2. Cool the mixture in step S1 to 70-80℃, then add 50-80 parts of bismaleimide resin and mix thoroughly to obtain the final product.

[0015] This invention explicitly proposes a stepwise, stepped temperature control process under non-solvent conditions. The first step is strictly limited to pre-dissolving the cyanate ester resin and epoxy resin at 100-120℃. The second step requires cooling to 70-80℃ before mixing with highly reactive bismaleimide powder to ensure the resin has a long processing life and effectively delays gelation.

[0016] In one preferred embodiment, step S1 uses a high-speed disperser for dispersion, and the stirring time in step S1 is 30-60 minutes.

[0017] In one preferred embodiment, step S2 uses a high-speed disperser for dispersion, and the time for thorough mixing in step S2 is 30-60 minutes.

[0018] The cooling rate in step S2 is 3-5℃ / min.

[0019] The present invention also discloses a prepreg prepared using the aforementioned high Tg modified high modulus bismaleimide resin composition.

[0020] The specific preparation method of prepreg includes the following steps: (1) The high Tg modified high modulus bismaleimide resin composition is melted into the coating tank. The melted high Tg modified high modulus bismaleimide resin composition is evenly coated onto the release paper through the gap between a pair of rollers of the coating machine to form two layers of resin film.

[0021] (2) The carbon fiber is sandwiched between the upper and lower resin films and heated and pressurized under the action of the heating plate and rollers, so that the resin penetrates into the fiber network. Finally, the release paper is peeled off and covered with PE film to obtain carbon fiber prepreg.

[0022] Preferably, the carbon fiber is T800 grade unidirectional carbon fiber; more preferably, it is Zhongfu Shenying SYT55S type 12K.

[0023] Preferably, the melting temperature in step (1) is 60-80℃.

[0024] Preferably, in step (1), the weight of the resin film is controlled to be 60-70g by adjusting the roller speed and roller gap.

[0025] Preferably, the heating temperature in step (2) is 90-110℃.

[0026] Preferably, the pressure applied in step (2) is 0.2-0.8 MPa.

[0027] Preferably, the resin content in the carbon fiber prepreg in step (2) is 30-40%, and more preferably 30-35%.

[0028] Preferably, the viscosity range of the prepreg is 20,000-35,000 cps, which is suitable for prepreg production.

[0029] The core of this invention lies not only in providing a modified quaternary formulation system that breaks through the limits of existing materials, but also in providing a matching solvent-free temperature-controlled molding process: locking the molding parameters of the above-mentioned resin system and T800 grade carbon fiber at a dynamic heating and pressurization temperature of 90-110℃. Since pure addition crosslinking does not release small molecules, combined with the excellent initial low viscosity advantage of this invention, a high-quality unidirectional prepreg with stable resin content and completely zero internal porosity is successfully prepared.

[0030] The present invention also discloses the application of the high Tg modified high modulus bismaleimide resin composition and the prepreg in aerospace heat-resistant structural components.

[0031] The specific steps in the fabrication method of the structural component include: The prepreg is heated to 200-300℃ and kept at that temperature using an autoclave curing process to obtain laminate.

[0032] The autoclave curing process involves starting at room temperature and increasing the temperature at 1-3℃ / min to 100-200℃, holding at 4-8 bar pressure for 1-3 hours, and then increasing the temperature at 1-3℃ / min to 200-300℃.

[0033] After heating to 200-300℃, the holding time is 3-5 hours.

[0034] Compared with the US patent with publication number WO2025123873A1, the test results of that patent, except for a lower Tg, show that the modulus tested in this invention is the composite material modulus, which is significantly higher than the modulus in the US patent with publication number WO2025123873A1. The energy storage modulus in DMA remains extremely stable up to 370°C, consistently around 80 GPa, and the room temperature flexural modulus is as high as around 140 GPa. A possible reason is that the flame retardant used in this design affects the mechanical properties (semiconductor packaging film materials typically require flame retardant properties), and the wide range of functional raw materials selected, such as epoxy resins, interact with other components, affecting the overall Tg and modulus.

[0035] The epoxy resin, cyanate ester resin, and bismaleimide resin selected in this invention have a significant impact on mechanical properties or Tg. The formulation results of some types of resins other than those in this invention show significant differences. Although some materials may theoretically have no impact on the results, it was found in the experiment that the effect was significantly worse than that of the resin types selected in this invention.

[0036] Compared to Chinese Patent CN107523055B, this method uses different resin systems to interpenetrate and increase crosslinking density, lacking the dense advantage of crosslinking interpenetrating networks with different groups. Therefore, its Tg and modulus are still lower than those in this invention. Furthermore, its preparation process is harsh and complex, and it is questionable whether the resin state meets the semi-solid state required for prepreg preparation. The resin prepared in this invention has been precisely calculated and extensively experimented with to determine its formulation, which is beneficial for prepreg preparation.

[0037] The system of this invention achieves in-situ toughening by cleverly triggering the Claisen rearrangement of DABPA; simultaneously, it utilizes a rigid epoxy resin with strong polarity and a large aromatic ring as a chemically compatible interfacial bridge, effectively improving the physicochemical interlocking force between the high-rigidity multiphase resin mixture and the carbon fiber surface. This technology enables the material to possess ultra-high Tg while still maintaining excellent high-temperature interlaminar shear strength retention (approximately 60%).

[0038] This invention solves the application problem caused by the industry's forced use of expensive polyimides to withstand high temperatures of 350°C. It avoids the internal dry spots and micropore defects caused by the release of large amounts of highly polar solvents and small molecule byproducts during the high-temperature polycondensation molding stage of PI resin. It perfectly achieves the balance between molding processability and extreme service safety through a low-cost hot melt method with zero exhaust pure addition reaction.

[0039] When the curing thermal field rises above 200°C, the allyl group within the bisphenol A dielyl ether molecule undergoes a highly regioselective σ[3,3] monocyclic rearrangement (Claisen rearrangement) via a classic six-membered ring transition state, transforming into o-diallyl bisphenol A with active phenolic hydroxyl groups. This phase transition, triggered by a timed temperature field, not only exposes new catalytic sites, but the regenerated active double bonds undergo allylation and Ene addition with maleimide groups, which is the fundamental reason for endowing the microscopic rigid skeleton with compliant aliphatic chain segments.

[0040] The phenol-biphenyl type epoxy resin upon which the formulation relies has a molecular backbone design that largely removes the flexible aliphatic segments of ordinary bisphenol A type epoxy resins, replacing them with biphenyl aromatic heterocycles. Therefore, it possesses extremely excellent basic heat resistance, low dielectric constant, and flame retardant stability. Furthermore, the selected TPM (triphenylmethane) type epoxy resin, with its high functionality and large, rigid benzene ring structure in the side chains, significantly locks down polymer chain slippage at high temperatures.

[0041] The synergistic curing of bismaleimide resin (BMI), cyanate ester resin (CE), and epoxy resin (EP) is a non-linear superposition. During a specific thermosetting process, the cyanate ester resin undergoes homopolymerization to form a highly stable triazine network. Simultaneously, its cyanate ester groups readily undergo ring-opening copolymerization with the epoxy groups, directionally generating a five-membered oxazolinone ring structure with extremely stable structure and exceptionally high heat resistance. These newly generated heterocyclic groups directly constitute the physicochemical crosslinking core of the full interpenetrating network (Full-IPN), providing the underlying microscopic scientific support for achieving an extremely high macroscopic glass transition temperature above 387°C in this invention.

[0042] Compared with existing technologies, the beneficial effects of this invention are as follows: Bisphenol A diallyl ether, as a liquid active material, significantly lowers the melting point of the system, greatly improves the processability of the prepreg, and does not react with bismaleimide resin at lower temperatures, giving the prepreg an excellent long-term storage period. When the curing temperature rises above 200°C, bisphenol A diallyl ether undergoes a Claisen rearrangement to transform into o-diallylbisphenol A. At this time, its terminal olefin bond undergoes an allylation reaction and an ENE addition reaction with the unsaturated double bond in the bismaleimide resin, effectively increasing the network crosslink chain length and flexibility, and significantly improving the inherent brittleness of the bismaleimide resin.

[0043] The selected cyanate ester resin undergoes triazine self-polymerization at high temperatures, forming a triazine ring structure with extremely high rigidity and high Tg. Simultaneously, the double / triple bonds within the cyanate ester react synergistically with the bismaleimide resin to generate a high-rigidity epoxy resin with a bismaleimide-triazine (BT) resin structure ratio. This resin not only undergoes self-ring-opening crosslinking catalyzed by the tertiary amine groups in the bismaleimide and cyanate ester but also reacts with the cyanate ester to generate a heat-resistant oxazolinone ring.

[0044] This invention utilizes the self-curing of bismaleimide resin, cyanate ester resin, and epoxy resin, along with deep copolymerization (such as BT structures and oxazolinones), to ultimately form an extremely complex and dense interpenetrating polymer network (IPN) within the system. This unique structure enables the system to form a highly cross-linked rigid framework after complete thermoaddition reaction. The glass transition temperature (Tg) of the cured product breaks through the 380℃ limit, allowing it to withstand high temperatures of 350℃ for extended periods and exhibiting superior high modulus and high strength compared to single-component systems. Attached Figure Description

[0045] Figure 1 This is a macroscopic image of the high Tg, high modulus modified bismaleimide resin composition prepared in Example 1.

[0046] Figure 2 The image shows a physical sample of a unidirectional prepreg with a 33% resin content, prepared by combining the resin composition of Example 1 with Zhongfu Shenying SYT55S type 12K carbon fiber.

[0047] Figure 3 The DMA thermomechanical analysis curve of the standard composite laminate prepared by the prepreg in Example 1 (due to the influence of the temperature measuring instrument's maximum limit of 400°C, the intersection of the storage modulus tangents is shown as 387°C, while the actual theoretical extrapolation value exceeds 390°C). Detailed Implementation

[0048] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0049] Example 1

[0050] This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts BMI-1000: 50 copies Bisphenol A cyanate: 5 parts SQXN-321: 5 copies The weighed bisphenol A dielyl ether was heated to 100°C in a high-speed disperser, bisphenol A cyanate and SQXN-321 were added, and the mixture was kept at this temperature for 30 minutes to dissolve completely. The temperature was then lowered to 70°C, BMI-1000 was added, and the mixture was thoroughly mixed for 30 minutes before being discharged.

[0051] The main performance tests of the resin composition are shown in Table 2.

[0052] The prepreg preparation process is as follows: The above-mentioned resin composition was melted at 70°C into a coating tank, and a resin film with a basis weight controlled at 67g was coated onto the release paper using a coating machine. Next, T800 grade unidirectional carbon fiber (Zhongfu Shenying SYT55S type 12K) was sandwiched between two layers of this resin film, and heated and pressurized under the action of the heating plate and rollers (100°C) of the prepreg machine, so that the resin could deeply penetrate into the fiber network. Finally, the release paper was peeled off and covered with a PE film to obtain a carbon fiber unidirectional prepreg with a resin content precisely controlled at 33%.

[0053] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0054] Example 2

[0055] This invention relates to an ultra-high Tg bismaleimide resin composition and prepreg, and a method for preparing the same, comprising the following raw materials by weight: Bisphenol A dielyl ether: 10 parts BMI-2300: 80 units Bisphenol F cyanate: 20 parts SQTN-331: 15 copies The weighed bisphenol A diallyl ether was heated to 120°C in a high-speed disperser, bisphenol F cyanate and SQTN-331 were added, and the mixture was kept at this temperature for 60 minutes to dissolve completely. The temperature was then lowered to 80°C, BMI-2300 was added, and the mixture was thoroughly mixed for 60 minutes before being discharged.

[0056] The main performance tests of the resin composition are shown in Table 2.

[0057] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0058] Example 3

[0059] This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 7.5 parts BMI-4000: 35 samples; BMI-600: 20 samples; BMI-700: 10 samples Bisphenol M cyanate: 3.5 parts; Bicycloisoprene cyanate: 3.5 parts; Bisphenol E cyanate: 3.5 parts SQXN-323: 5 copies; SQTN-333: 5 copies The weighed bisphenol A diallyl ether was heated to 110°C in a high-speed disperser. Bisphenol M cyanate, bicycloisoprene cyanate, bisphenol E cyanate, SQXN-323 and SQTN-333 were added and kept at this temperature for 45 minutes to dissolve completely. The temperature was then lowered to 75°C, and BMI-4000, BMI-600 and BMI-700 were added. The mixture was thoroughly mixed for 45 minutes and then discharged.

[0060] The main performance tests of the resin composition are shown in Table 2.

[0061] The prepreg prepared from the above bismaleimide resin composition was cured in an autoclave (heating from room temperature to 200°C at a rate of 2°C / min, holding at 6 bar for 2 hours, then heating to 250°C at a rate of 2°C / min and holding for 4 hours). The main properties of the resulting laminate are shown in Table 2.

[0062] Comparative Example 1 (without epoxy resin and cyanate ester modification) This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts BMI-1000: 50 copies The weighed bisphenol A dielyl ether was heated to 100°C in a high-speed disperser, bisphenol A cyanate and SQXN-321 were added, and the mixture was kept at this temperature for 30 minutes to dissolve completely. The temperature was then lowered to 70°C, BMI-1000 was added, and the mixture was thoroughly mixed for 30 minutes before being discharged.

[0063] The main performance tests of the resin composition are shown in Table 2.

[0064] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0065] Comparative Example 2 (lacking cyanate ester component) This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts; BMI-1000: 50 copies; SQXN-321: 5 copies.

[0066] The weighed bisphenol A dielyl ether was heated to 100°C in a high-speed disperser, SQXN-321 was added, and the mixture was kept at this temperature for 30 minutes to dissolve completely. The temperature was then lowered to 70°C, BMI-1000 was added, and the mixture was thoroughly mixed for 30 minutes before being discharged.

[0067] The main performance tests of the resin composition are shown in Table 2.

[0068] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0069] Comparative Example 3 (without epoxy resin component) This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts; BMI-1000: 50 copies; Bisphenol A cyanate: 5 parts.

[0070] The weighed bisphenol A dielyl ether was heated to 100°C in a high-speed disperser, bisphenol A cyanate was added, and the mixture was kept at this temperature for 30 minutes to dissolve completely. The temperature was then lowered to 70°C, BMI-1000 was added, and the mixture was thoroughly mixed for 30 minutes before being discharged.

[0071] The main performance tests of the resin composition are shown in Table 2.

[0072] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0073] Comparative Example 4 (using conventional toluene-based bismaleimide resin instead) This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts; BMI-7000 (Conventional Toluene-based Dimethyl Benzyl): 50 parts; Bisphenol A cyanate: 5 parts; SQXN-321: 5 copies.

[0074] The preparation process is the same as in Example 1.

[0075] The main performance tests of the resin composition are shown in Table 2.

[0076] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0077] Comparative Example 5 (replacing phenolic cyanate ester) This invention relates to a high Tg, high modulus modified bismaleimide resin composition and a method for preparing a prepreg, which consists of the following raw materials by weight: bisphenol A dielyl ether: 5 parts; BMI-1000: 50 copies; Phenolic cyanate: 5 parts; SQXN-321: 5 copies.

[0078] The preparation process is the same as in Example 1.

[0079] The main performance tests of the resin composition are shown in Table 2.

[0080] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0081] Comparative Example 6 (replacing with conventional tetrafunctional epoxy resin) This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts; BMI-1000: 50 copies; Bisphenol A cyanate: 5 parts; MF-4101H (Zhenzhengfeng tetrafunctional group epoxy): 5 parts.

[0082] The preparation process is the same as in Example 1.

[0083] The main performance tests of the resin composition are shown in Table 2.

[0084] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0085] Comparative Example 7 (increasing the proportion of cyanate ester) This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts BMI-1000: 50 copies Bisphenol A cyanate: 30 parts SQXN-321: 5 copies The preparation process is the same as in Example 1.

[0086] The main performance tests of the resin composition are shown in Table 2.

[0087] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0088] Comparative Example 8 (increased epoxy resin ratio) This invention relates to a high-Tg, high-modulus modified bismaleimide resin composition and a method for preparing a prepreg, comprising the following raw materials by weight: Bisphenol A dielyl ether: 5 parts BMI-1000: 50 copies Bisphenol A cyanate: 5 parts SQXN-321: 20 copies The weighed bisphenol A dielyl ether was heated to 100°C in a high-speed disperser, bisphenol A cyanate and SQXN-321 were added, and the mixture was kept at this temperature for 30 minutes to dissolve completely. The temperature was then lowered to 70°C, BMI-1000 was added, and the mixture was thoroughly mixed for 30 minutes before being discharged.

[0089] The main performance tests of the resin composition are shown in Table 2.

[0090] The prepreg prepared by the above bismaleimide resin composition was cured in an autoclave (starting from room temperature, the temperature was increased to 200℃ at 2℃ / min and held at 6 bar for 2 hours, and then increased to 250℃ at 2℃ / min and held for 4 hours) to obtain the main properties of the laminate, as shown in Table 2.

[0091] Table 1. Ingredients of Examples and Comparative Examples Table 2. Performance Comparison of Resin Compositions or Laminates in Examples and Comparative Examples The data from Examples 1-3 showed minimal differences, and the glass transition temperature (Tg) of the system remained remarkably stable above 380°C. Even under the extreme testing environment of 350°C, the data retention rates for flexural strength, modulus, and interlaminar shear strength were approximately 50%, 50%, and 60%, respectively, demonstrating extremely rare and exceptional thermodynamic stability. In comparison: In Comparative Example 1, without the addition of cyanate ester and epoxy resin modification, the Tg decreased significantly, the flexural modulus also decreased, and all mechanical properties at high temperatures decreased. In addition, the overall viscosity of the resin increased significantly, increasing the difficulty of prepreg production. In Comparative Example 2, after removing the cyanate ester core network, the Tg of the system collapsed and decreased significantly, the flexural modulus at room temperature deteriorated greatly, and the flexural strength and retention rate at extremely high temperatures decreased extremely significantly. In Comparative Example 3, after removing the special epoxy resin that acts as a phase interface bridge, not only did the conventional properties decline similarly to Comparative Example 1, but the material also underwent layer-by-layer debonding at 350℃, and the interlaminar shear strength and retention rate showed a devastating decrease. In Comparative Example 4, after replacing the specific rigid bismaleimide with ordinary toluene-type bismaleimide, the main chain rigidity was lost, the Tg plummeted, and the matrix was lost at high temperatures. The load-bearing capacity of this invention is demonstrated by the following comparisons: Comparative Example 5, which forcibly replaced the highly reactive phenolic cyanate ester with a cyanate ester, caused severe kinetic imbalance and microphase separation during the curing reaction. While exhibiting a high Tg, the interlayer shear capacity essentially collapsed at high temperatures. Comparative Example 6, which blindly adopted a commercially available tetrafunctional epoxy, induced a violent ring-opening preemptive reaction before reaching the reaction window. This resulted in a significant reduction in gel time, uncontrolled processing viscosity, and a precipitous drop in Tg and all high- and low-temperature mechanical properties. Comparative Example 7, which increased the cyanate ester ratio, showed a significant decrease in all mechanical properties, including a slight decrease in Tg. Comparative Example 8, which increased the epoxy resin ratio, showed a significant decrease in all mechanical properties and Tg, except for a slight decrease in interlayer shear capacity. These comparisons fully verify the highly irreplaceable nature of the specific quaternary component system in achieving full interpenetrating network synergy in this invention.

[0092] Compared to Comparative Example 1 (without epoxy resin and cyanate modification), Comparative Example 2 (lacking cyanate component) showed a 15°C increase in Tg. Comparative Example 3 (lacking epoxy resin component) showed an 8°C increase in Tg compared to Comparative Example 1 (without epoxy resin and cyanate modification). However, Example 1 (with both epoxy resin and cyanate modification) showed a 68°C increase in Tg compared to Comparative Example 1 (without epoxy resin and cyanate modification). This demonstrates that, based on the basic components, the Tg increase resulting from the simultaneous addition of epoxy resin and cyanate modification in Example 1 is significantly greater than the sum of the increases from adding epoxy resin alone and adding cyanate alone, proving a synergistic effect between the addition of epoxy resin and cyanate modification, which significantly improved Tg.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-Tg modified high-modulus bismaleimide resin composition, characterized in that, The raw materials include the following parts by weight: 5-10 parts bisphenol A dielyl ether, 50-80 parts bismaleimide resin, 5-20 parts cyanate ester resin, and 5-15 parts epoxy resin. The main molecular chain of the bismaleimide resin contains an aromatic ring or a biphenyl structure. The epoxy resin includes multiple continuous aromatic heterocyclic epoxy resins, phenol-biphenyl type epoxy resins, or triphenylmethane type epoxy resins.

2. The high Tg modified high modulus bismaleimide resin composition according to claim 1, characterized in that, The cyanate resin includes one or more of bisphenol A cyanate, bisphenol F cyanate, bisphenol M cyanate, dicyclopentadiene cyanate, and bisphenol E cyanate.

3. The high Tg modified high modulus bismaleimide resin composition according to claim 1, characterized in that, The bismaleimide resin is selected from one or more of BMI-1000, BMI-2300, BMI-4000, BMI-5100, BMI-600, and BMI-700.

4. The high Tg modified high modulus bismaleimide resin composition according to claim 1, characterized in that, The phenol-biphenyl type epoxy resin is selected from one or more of Jinan Shengquan SQXN-321, SQXN-322, SQXN-323, and SQXN-324.

5. The high Tg modified high modulus bismaleimide resin composition according to claim 2, characterized in that, The triphenylmethane-type epoxy resin is selected from one or more of Jinan Shengquan SQTN-331, SQTN-332, and SQTN-333.

6. A method for preparing the high Tg modified high modulus bismaleimide resin composition according to any one of claims 1-5, characterized in that... Includes the following steps: S1. Disperse 5-10 parts of bisphenol A dielyl ether evenly and heat to 100-120℃, then add 5-15 parts of epoxy resin and 5-20 parts of cyanate ester resin, and continue stirring to fully dissolve the solid resin to obtain a mixture. S2. Cool the mixture in step S1 to 70-80℃, then add 50-80 parts of bismaleimide resin and mix thoroughly to obtain the final product.

7. The method for preparing the high Tg modified high modulus bismaleimide resin composition according to claim 6, characterized in that, Step S1 uses a high-speed disperser for dispersion, and the stirring time in step S1 is 30-60 minutes.

8. The method for preparing the high Tg modified high modulus bismaleimide resin composition according to claim 6, characterized in that, Step S2 uses a high-speed disperser for dispersion, and the time for thorough mixing in step S2 is 30-60 minutes.

9. A prepreg, characterized in that, It was prepared using the high Tg modified high modulus bismaleimide resin composition according to any one of claims 1-5.

10. The application of a high Tg modified high modulus bismaleimide resin composition according to any one of claims 1-5, and the prepreg according to claim 9, in aerospace heat-resistant structural components.

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