Epoxy resin-based prepreg with high temperature resistance and low dielectric property and preparation method of epoxy resin-based prepreg

Abstract

The invention discloses an epoxy resin-based prepreg with high temperature resistance and low dielectric properties and a preparation method thereof. Researches show that by introducing proper groups, a resin matrix can be endowed with good high-temperature resistance, and the glass-transition temperature of an epoxy resin system can be synergistically improved. Moreover, regular and symmetrical groups are introduced into a molecular main chain through molecular structure design, so that the polarity and dipole moment of the molecular chain can be reduced, and the dielectric property of the material is improved. Besides, by reasonably controlling the raw material ratio and the modification process route, the high-temperature-resistant low-dielectric epoxy resin disclosed by the invention has a chemical adhesion effect, the viscosity of a prepreg resin system can be improved, and the fluidity and permeability of a resin matrix in the molding process of the prepreg are ensured.

Description

[0001] Cross-references to related applications This application is a divisional application of application CN202510635992.3 filed on May 16, 2025, entitled "A High-Temperature Resistant Low-Dielectric Epoxy Resin Prepreg and Its Preparation Method and Application", which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention belongs to the field of composite material technology, and in particular relates to an epoxy resin-based prepreg with both high temperature resistance and low dielectric properties and its preparation method. Background Technology

[0003] With the rapid development of high-tech fields such as high-frequency communication, the demand for high-temperature resistant, low-dielectric epoxy resin-based composite materials is increasing. In certain special applications, traditional epoxy prepregs suffer from poor high-temperature resistance and insufficient dielectric properties, leading to softening and decomposition at high temperatures, resulting in performance degradation, signal delay, and energy loss, making it difficult to meet the stringent material requirements of high-tech industries. Therefore, developing epoxy resin-based prepregs that combine high-temperature resistance and low dielectric properties has become a current research hotspot.

[0004] Chinese invention patent application CN104726045A achieves a product temperature resistance of 250℃ by using a matrix epoxy resin containing heat-resistant groups such as aromatic rings, alicyclic rings, and heterocyclic rings on the molecular chain. However, the epoxy resin prepared by this method has a high dielectric property due to the addition of alumina filler. Furthermore, Chinese invention patent application CN119217811A improves the dielectric and heat resistance of the material by introducing cage-type polysilsesquioxane resin (POSS) in combination with a specific ratio of dicyclopentadiene phenol-modified epoxy resin and inorganic fillers such as silica powder. However, the addition of a large amount of filler makes it difficult to disperse evenly, resulting in poor film-forming properties of the resin system and making it difficult to meet the process characteristics required for prepreg preparation.

[0005] Therefore, there is an urgent need to develop an epoxy resin-based prepreg that is resistant to high temperatures, has low dielectric properties, and can meet the requirements of prepreg preparation processes. Summary of the Invention

[0006] To address at least some of the technical problems in the prior art, the present invention provides an epoxy resin-based prepreg with both high-temperature resistance and low dielectric properties, and a method for preparing the same. Specifically, the present invention includes the following:

[0007] In a first aspect, the present invention provides an epoxy resin-based prepreg that combines high temperature resistance and low dielectric properties, which is prepared from raw materials comprising: 0.05-1 parts by weight of a first catalyst, 1-200 parts by weight of epoxy resin, 1-200 parts by weight of a diisocyanate compound, 0.05-1 parts by weight of a second catalyst, 1-20 parts by weight of a hydroxyl-terminated polyphenylene ether, 1-100 parts by weight of a liquid epoxy resin and 1-20 parts by weight of a latent curing system, wherein the diisocyanate compound contains a naphthalene ring, biphenyl, or p-phenylene structure.

[0008] In some embodiments, the epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to the present invention, wherein the first catalyst comprises at least one of imidazole, imidazole derivatives, Lewis acids and base complexes.

[0009] In some embodiments, the epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to the present invention includes at least one of bisphenol A glycidyl ether, bisphenol F glycidyl ether, bisphenol AD ​​glycidyl ether, liquid phenolic epoxy resin, and alicyclic epoxy resin.

[0010] In some embodiments, the epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to the present invention, wherein the diisocyanate compound includes at least one of 1,5-naphthalene diisocyanate, dimethyl biphenyl diisocyanate, and terephthalic diisocyanate.

[0011] In some embodiments, the epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to the present invention, wherein the second catalyst comprises at least one of triphenylphosphine and tetramethylammonium hydroxide.

[0012] In some embodiments, the epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to the present invention, wherein the latent curing system includes at least one of dicyandiamide, modified dicyandiamide, and urea derivatives.

[0013] In some embodiments, the epoxy resin-based prepreg according to the present invention, which combines high temperature resistance and low dielectric properties, further comprises fibers.

[0014] In some embodiments, the epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to the present invention, wherein the fibers include at least one of alkali-free glass fibers, high-strength glass fibers, and quartz fibers.

[0015] A second aspect of the present invention provides a method for preparing an epoxy resin-based prepreg that combines high temperature resistance and low dielectric properties, comprising the following steps: (1) In the presence of a first catalyst, epoxy resin and diisocyanate compound containing aromatic groups are reacted at 120-160℃ for 2-4 h, and double-terminated hydroxyl polyphenylene ether is added. In the presence of a second catalyst, the reaction is continued for 1-3 h to obtain high temperature resistant low dielectric epoxy resin, wherein the molar ratio of epoxy resin to diisocyanate compound is (3-6):1. (2) Mix the high-temperature resistant low-dielectric epoxy resin with liquid epoxy resin and latent curing system to obtain a resin system for prepreg, wherein the liquid epoxy resin is 20-50 parts by weight relative to 100 parts by weight of the high-temperature resistant low-dielectric epoxy resin, and the latent curing system is 6-12 parts by weight. (3) The prepreg is prepared into a film using a resin system and then compounded with fibers to obtain the high-temperature resistant, low-dielectric epoxy resin prepreg.

[0016] In some embodiments, according to the preparation method of the present invention, in step (1), the amount of the first catalyst is 0.1-1% of the sum of the mass of the epoxy resin and the diisocyanate compound, the amount of the second catalyst is 0.1-1% of the sum of the mass of the epoxy resin and the diisocyanate compound, and the amount of the hydroxyl-terminated polyphenylene ether is 5-15% of the sum of the mass of the epoxy resin and the diisocyanate compound.

[0017] A third aspect of the present invention provides the application of an epoxy resin-based prepreg, which combines high temperature resistance and low dielectric properties according to the first aspect of the present invention, in high-frequency communication equipment.

[0018] This invention has discovered that diisocyanates containing naphthalene rings, biphenyl, or p-phenyl groups can impart excellent high-temperature resistance to the resin matrix, while polyphenylene ether can synergistically increase the glass transition temperature of the epoxy resin system. Furthermore, this invention, through molecular structure design, introduces regular and symmetrical naphthalene rings, biphenyl, or p-phenyl groups into the molecular backbone, reducing the polarity and dipole moment of the molecular chain, thereby improving the dielectric properties of the material and achieving a synergistic effect with polyphenylene ether to enhance the dielectric properties of epoxy resin.

[0019] Furthermore, by rationally controlling the raw material ratio and modification process route, this invention uses diisocyanate containing aromatic groups as a linear chain extender for epoxy resin. This increases the distance between rigid crosslinking points in the cured crosslinking network, imparting toughness to the resin system and increasing the initial viscosity of the resin matrix. Furthermore, the introduction of polyphenylene ether segments improves the flexibility of the resin matrix and increases the viscosity of the resin system. Therefore, the high-temperature resistant, low-dielectric epoxy resin of this invention has a chemically tackifying effect, which can increase the viscosity of the prepreg resin system and ensure the fluidity and permeability of the resin matrix during the molding process. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] Preparation method One aspect of the present invention provides a method for preparing a high-temperature resistant, low-dielectric epoxy resin prepreg.

[0024] In a preferred embodiment, the preparation method of the present invention includes the following steps: (1) In the presence of a first catalyst, epoxy resin is reacted with a diisocyanate compound containing aromatic groups at 120-160℃ (e.g., 120, 125, 130, 135, 140, 145, 150, 155, 160℃) for 2-4 h (e.g., 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4 h). Then, dihydroxyl-terminated polyphenylene ether is added, and in the presence of a second catalyst, the reaction is continued for 1-3 h (e.g., 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3 h). h), to obtain a high-temperature resistant, low-dielectric epoxy resin, wherein the molar ratio of the epoxy resin to the diisocyanate compound is (3-6):1, for example 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1; (2) The high-temperature resistant low-dielectric epoxy resin is mixed with liquid epoxy resin and latent curing system to obtain a resin system for prepreg, wherein the high-temperature resistant low-dielectric epoxy resin is 100 parts by weight, the liquid epoxy resin is 20-50 parts by weight, and the latent curing system is 6-12 parts by weight. (3) The prepreg is prepared into a film using a resin system and then compounded with fibers to obtain the high-temperature resistant, low-dielectric epoxy resin prepreg.

[0025] To improve the high-temperature resistance and dielectric properties of high-temperature resistant, low-dielectric epoxy resin prepreg, the molar ratio of epoxy resin to diisocyanate compound should not be too high or too low, and the amount of catalyst must be controlled within a suitable range. In this invention, the molar ratio of epoxy resin to diisocyanate compound is (3-6):1, for example, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, or any ratio within the above range. The amount of the first catalyst is 0.1-1% of the sum of the mass of the epoxy resin and diisocyanate compound, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. In a preferred embodiment, the molar ratio of epoxy resin to diisocyanate compound is 6:1, and the amount of the first catalyst is 1% of the sum of the mass of the epoxy resin and diisocyanate compound. In another preferred embodiment, the molar ratio of the epoxy resin to the diisocyanate compound is 4.5:1, and the amount of the first catalyst is 0.55% of the sum of the mass of the epoxy resin and the diisocyanate compound. In yet another preferred embodiment, the molar ratio of the epoxy resin to the diisocyanate compound is 3:1, and the amount of the first catalyst is 0.1% of the sum of the mass of the epoxy resin and the diisocyanate compound.

[0026] To improve the high-temperature resistance and dielectric properties of high-temperature resistant, low-dielectric epoxy resin prepreg, the amount of the bihydroxyl-terminated polyphenylene ether (BPE) should not be too high or too low, and the amount of catalyst should be controlled within a suitable range. If the amount of BPE is too high, the curing performance of the epoxy resin tends to deteriorate; if the amount of BPE is too low, the dielectric properties of the prepreg tend to deteriorate. In a preferred embodiment, the amount of the BPE is 5-15% of the sum of the mass of the epoxy resin and the diisocyanate compound, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or any value within the above range; and the amount of the second catalyst is 1% of the sum of the mass of the epoxy resin and the diisocyanate compound, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any value within the above range.

[0027] In one preferred embodiment, the amount of the hydroxyl-terminated polyphenylene ether is 15% of the sum of the mass of the epoxy resin and the diisocyanate compound, and the amount of the second catalyst is 1% of the sum of the mass of the epoxy resin and the diisocyanate compound. In another preferred embodiment, the amount of the hydroxyl-terminated polyphenylene ether is 10% of the sum of the mass of the epoxy resin and the diisocyanate compound, and the amount of the second catalyst is 0.55% of the sum of the mass of the epoxy resin and the diisocyanate compound. In yet another preferred embodiment, the amount of the hydroxyl-terminated polyphenylene ether is 5% of the sum of the mass of the epoxy resin and the diisocyanate compound, and the amount of the second catalyst is 0.1% of the sum of the mass of the epoxy resin and the diisocyanate compound.

[0028] In this invention, the first catalyst comprises at least one selected from imidazole, imidazole derivatives, and Lewis acid-base complexes. In a preferred embodiment, the first catalyst is imidazole. In another preferred embodiment, the first catalyst is an imidazole derivative. In yet another preferred embodiment, the first catalyst is a Lewis acid.

[0029] In this invention, the epoxy resin includes at least one selected from bisphenol A glycidyl ether, bisphenol F glycidyl ether, bisphenol AD ​​glycidyl ether, liquid phenolic epoxy resin, and alicyclic epoxy resin. In a preferred embodiment, the epoxy resin is a bisphenol A glycidyl ether type epoxy resin. In another preferred embodiment, the epoxy resin is a bisphenol F glycidyl ether type epoxy resin and a bisphenol AD ​​glycidyl ether type epoxy resin. In yet another preferred embodiment, the epoxy resin is a liquid phenolic epoxy resin.

[0030] In this invention, the aromatic diisocyanate compound includes at least one selected from 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, and terephthalic diisocyanate. In a preferred embodiment, the diisocyanate compound is 1,5-naphthalene diisocyanate. In another preferred embodiment, the diisocyanate compound is 1,5-naphthalene diisocyanate and dimethylbiphenyl diisocyanate. In yet another preferred embodiment, the diisocyanate compound is terephthalic diisocyanate.

[0031] In this invention, the second catalyst comprises at least one of triphenylphosphine and tetramethylammonium hydroxide. In a preferred embodiment, the second catalyst is triphenylphosphine. In another preferred embodiment, the second catalyst is triphenylphosphine and tetramethylammonium hydroxide. In yet another preferred embodiment, the second catalyst is tetramethylammonium hydroxide.

[0032] In this invention, the latent curing system comprises at least one of dicyandiamide, modified dicyandiamide, and urea derivatives. In a preferred embodiment, the latent curing system is dicyandiamide. In another preferred embodiment, the latent curing system comprises dicyandiamide and modified dicyandiamide. In yet another preferred embodiment, the latent curing system is a urea derivative.

[0033] In this invention, the fiber comprises at least one selected from alkali-free glass fiber, high-strength glass fiber, and quartz fiber. In a preferred embodiment, the fiber is high-strength glass fiber. In another preferred embodiment, the fiber is alkali-free glass fiber. In a preferred embodiment, the fiber is quartz fiber.

[0034] The present invention has found that diisocyanate compounds containing naphthalene rings, biphenyl or p-phenyl groups and hydroxyl-terminated polyphenylene ethers can synergistically improve the temperature resistance of epoxy resin prepregs, and at the same time synergistically improve the dielectric properties of epoxy resin prepregs.

[0035] High-temperature resistant, low-dielectric epoxy resin prepreg In one aspect, the present invention provides a high-temperature resistant, low-dielectric epoxy resin prepreg obtained by the preparation method described in the present invention.

[0036] In this invention, the high-temperature resistant, low-dielectric epoxy resin prepreg is prepared from the following raw materials: 0.05-1 parts by weight of a first catalyst, 1-200 parts by weight of epoxy resin, 1-200 parts by weight of a diisocyanate compound, 0.05-1 parts by weight of a second catalyst, 1-20 parts by weight of a hydroxyl-terminated polyphenylene ether, 1-100 parts by weight of a liquid epoxy resin, and 1-20 parts by weight of a latent curing system.

[0037] In a preferred embodiment, the high-temperature resistant, low-dielectric epoxy resin prepreg is prepared from raw materials comprising: 0.1-1 parts by weight of a first catalyst, 1-100 parts by weight of epoxy resin, 1-100 parts by weight of a diisocyanate compound, 0.1-1 parts by weight of a second catalyst, 5-15 parts by weight of a hydroxyl-terminated polyphenylene ether, 20-50 parts by weight of a liquid epoxy resin, and 6-12 parts by weight of a latent curing system.

[0038] In a preferred embodiment, the high-temperature resistant, low-dielectric epoxy resin prepreg is prepared from raw materials comprising: 1-100 parts by weight of epoxy resin, 1-100 parts by weight of diisocyanate compound, 5-15 parts by weight of hydroxyl-terminated polyphenylene ether, 20-50 parts by weight of liquid epoxy resin and 6-12 parts by weight of latent curing system.

[0039] In this invention, the glass transition temperature, interlaminar shear strength, dielectric constant and dielectric loss of the high-temperature resistant low-dielectric epoxy resin prepreg can be determined using methods and apparatus known in the art, and there are no particular limitations thereto.

[0040] In a preferred embodiment, the high-temperature resistant, low-dielectric epoxy resin prepreg of the present invention has a glass transition temperature of 173-180°C.

[0041] In a preferred embodiment, the high-temperature resistant, low-dielectric epoxy resin prepreg of the present invention has an interlaminar shear strength of 60-70 MPa (25°C).

[0042] In a preferred embodiment, the high-temperature resistant, low-dielectric epoxy resin prepreg of the present invention has an interlaminar shear strength of 53-63 MPa (100°C).

[0043] In a preferred embodiment, the high-temperature resistant, low-dielectric epoxy resin prepreg of the present invention has a dielectric constant of 3.5-4.3.

[0044] In a preferred embodiment, the high-temperature resistant, low-dielectric epoxy resin prepreg of the present invention has a dielectric loss of 0.009-0.011.

[0045] application One aspect of the present invention provides the application of the high-temperature resistant, low-dielectric epoxy resin prepreg described herein in high-frequency communication equipment. Examples of such high-frequency communication equipment include, but are not limited to, satellite antennas, radar equipment, spaceborne communication equipment, solar panels, flight control equipment, navigation equipment, filters, etc.

[0046] Example 1 The following shows the preparation process and performance testing of high-temperature resistant, low-dielectric epoxy resin prepreg.

[0047] Bisphenol A glycidyl ether epoxy resin and 1,5-naphthalene diisocyanate were placed in a reactor at 120°C at a molar ratio of 6:1 and reacted for 4 hours under the action of an imidazole catalyst. Then, dihydroxyl-terminated polyphenylene ether was added, and the reaction was continued for 3 hours under the action of a triphenylphosphine catalyst to prepare a high-temperature resistant, low-dielectric epoxy resin. Specifically, relative to 100 parts by weight of the sum of the masses of bisphenol A glycidyl ether epoxy resin and 1,5-naphthalene diisocyanate, the amount of imidazole catalyst was 1 part by weight, the amount of dihydroxyl-terminated polyphenylene ether was 15 parts by weight, and the amount of triphenylphosphine catalyst was 1 part by weight.

[0048] To 100 parts by weight of the high-temperature resistant, low-dielectric epoxy resin obtained in the above steps, 50 parts by weight of bisphenol A glycidyl ether type epoxy resin and 12 parts by weight of dicyandiamide curing system were added and mixed evenly to prepare a prepreg resin system with excellent processability. The resin system was coated using a film-coating machine, and then laminated with high-strength glass fiber using a laminating machine to prepare a high-temperature resistant, low-dielectric epoxy resin prepreg. The glass transition temperature (DMA), interlaminar shear strength, and dielectric properties of the composite material were tested, and the results are shown in Table 1.

[0049] Example 2 The following shows the preparation process and performance testing of high-temperature resistant, low-dielectric epoxy resin prepreg.

[0050] Bisphenol F glycidyl ether type epoxy resin and bisphenol AD ​​glycidyl ether type epoxy resin were placed in a reactor at 140℃ with 1,5-naphthalene diisocyanate and dimethylbiphenyl diisocyanate at a molar ratio of 4.5:1 and reacted for 3 h under the action of an imidazole derivative catalyst. Then, a hydroxyl-terminated polyphenylene ether was added, and the reaction was continued for 2 h under the action of a triphenylphosphine and tetramethylammonium hydroxide catalyst to prepare a high-temperature resistant, low-dielectric epoxy resin. Specifically, relative to 100 parts by weight of the sum of the mass of bisphenol F glycidyl ether type epoxy resin and bisphenol AD ​​glycidyl ether type epoxy resin with 1,5-naphthalene diisocyanate and dimethylbiphenyl diisocyanate, the amount of imidazole derivative catalyst was 0.55 parts by weight, the amount of hydroxyl-terminated polyphenylene ether was 10 parts by weight, and the amount of triphenylphosphine and tetramethylammonium hydroxide catalyst was 0.55 parts by weight.

[0051] To 100 parts by weight of the high-temperature resistant, low-dielectric epoxy resin obtained in the above steps, 35 parts by weight of bisphenol A glycidyl ether epoxy resin and bisphenol F glycidyl ether epoxy resin, and 9 parts by weight of dicyandiamide and modified dicyandiamide curing system were added and mixed evenly to prepare a prepreg resin system with excellent processability. The resin system was coated using a film-forming machine, and then laminated with alkali-free glass fiber using a laminating machine to prepare a high-temperature resistant, low-dielectric epoxy resin prepreg. The glass transition temperature (DMA), interlaminar shear strength, and dielectric properties of the composite material were tested, and the results are shown in Table 1.

[0052] Example 3 The following shows the preparation process and performance testing of high-temperature resistant, low-dielectric epoxy resin prepreg.

[0053] Liquid phenolic epoxy resin and terephthalic diisocyanate were placed in a reactor at 160°C at a molar ratio of 3:1 and reacted for 2 hours under the action of a Lewis acid catalyst. Then, hydroxyl-terminated polyphenylene ether was added, and the reaction was continued for 1 hour under the action of a tetramethylammonium hydroxide catalyst to prepare a high-temperature resistant, low-dielectric epoxy resin. Specifically, relative to 100 parts by weight of the sum of the masses of liquid phenolic epoxy resin and terephthalic diisocyanate, the amount of Lewis acid catalyst was 0.1 parts by weight, the amount of hydroxyl-terminated polyphenylene ether was 5 parts by weight, and the amount of tetramethylammonium hydroxide catalyst was 0.1 parts by weight.

[0054] To 100 parts by weight of the high-temperature resistant, low-dielectric epoxy resin obtained in the above steps, 20 parts by weight of liquid phenolic epoxy resin and 6 parts by weight of urea derivative curing system were added and mixed evenly to prepare a prepreg resin system with excellent processability. The resin system was coated using a film-forming machine, and then laminated with quartz fiber using a composite machine to prepare a high-temperature resistant, low-dielectric epoxy resin prepreg. The glass transition temperature (DMA), interlaminar shear strength, and dielectric properties of the composite material were tested separately, and the results are shown in Table 1.

[0055] Comparative Example 1 The following shows the preparation process and performance testing of the modified epoxy resin-based prepreg.

[0056] Bisphenol A glycidyl ether epoxy resin and 1,5-naphthalene diisocyanate were placed in a reactor at 120°C at a molar ratio of 6:1 and reacted for 4 hours under the action of an imidazole catalyst to prepare a modified epoxy resin. The amount of imidazole catalyst used was 1 part by weight relative to 100 parts by weight of the sum of the masses of bisphenol A glycidyl ether epoxy resin and 1,5-naphthalene diisocyanate.

[0057] To 100 parts by weight of the modified epoxy resin obtained in the above steps, 50 parts by weight of bisphenol A glycidyl ether type epoxy resin and 12 parts by weight of dicyandiamide curing system were added and mixed evenly to prepare a prepreg resin system with excellent processability. The resin system was coated using a film-coating machine, and then laminated with high-strength glass fiber using a laminating machine to prepare a modified epoxy resin-based prepreg. The glass transition temperature (DMA), interlaminar shear strength, and dielectric properties of the composite material were tested, and the results are shown in Table 1.

[0058] Comparative Example 2 The following shows the preparation process and performance testing of the modified epoxy resin-based prepreg.

[0059] Bisphenol A glycidyl ether type epoxy resin and dihydroxyl-terminated polyphenylene ether were placed in a reactor at 120°C and reacted for 3 hours under the action of triphenylphosphine catalyst to prepare modified epoxy resin. Specifically, the amount of dihydroxyl-terminated polyphenylene ether was 15 parts by weight relative to 100 parts by weight of bisphenol A glycidyl ether type epoxy resin, and the amount of triphenylphosphine catalyst was 1 part by weight.

[0060] To 100 parts by weight of the modified epoxy resin obtained in the above steps, 50 parts by weight of bisphenol A glycidyl ether type epoxy resin and 12 parts by weight of dicyandiamide curing system were added and mixed evenly to prepare a prepreg resin system with excellent processability. The resin system was coated using a film-coating machine, and then laminated with high-strength glass fiber using a laminating machine to prepare a modified epoxy resin-based prepreg. The glass transition temperature (DMA), interlaminar shear strength, and dielectric properties of the composite material were tested, and the results are shown in Table 1.

[0061] Comparative Example 3 The following shows the preparation process and performance testing of the modified epoxy resin-based prepreg.

[0062] Bisphenol A glycidyl ether epoxy resin and liquefied diphenylmethane diisocyanate were placed in a reactor at 120°C at a molar ratio of 6:1 and reacted for 4 hours under the action of an imidazole catalyst. Then, dihydroxyl-terminated polyphenylene ether was added, and the reaction was continued for 3 hours under the action of a triphenylphosphine catalyst to prepare a high-temperature resistant, low-dielectric epoxy resin. Specifically, relative to 100 parts by weight of the sum of the masses of bisphenol A glycidyl ether epoxy resin and liquefied diphenylmethane diisocyanate, the amount of imidazole catalyst was 1 part by weight, the amount of dihydroxyl-terminated polyphenylene ether was 15 parts by weight, and the amount of triphenylphosphine catalyst was 1 part by weight.

[0063] To 100 parts by weight of the modified epoxy resin obtained in the above steps, 50 parts by weight of bisphenol A glycidyl ether type epoxy resin and 12 parts by weight of dicyandiamide curing system were added and mixed evenly to prepare a prepreg resin system with excellent processability. The resin system was coated using a film-coating machine, and then laminated with high-strength glass fiber using a laminating machine to prepare a modified epoxy resin-based prepreg. The glass transition temperature (DMA), interlaminar shear strength, and dielectric properties of the composite material were tested, and the results are shown in Table 1.

[0064] Compared with the comparative example, the high-temperature resistant and low-dielectric epoxy resin composite material prepared in the example has a glass transition temperature >170℃, an interlaminar shear strength retention rate >80% at 100℃, can be used for a long time in an environment of 100℃, a dielectric constant ≤4.3, and a dielectric loss ≤0.011, exhibiting excellent high-temperature resistance and dielectric properties. In Comparative Example 1, the composite material prepared using 1,5-naphthalene diisocyanate-modified epoxy resin achieved a glass transition temperature of 165°C, but its dielectric constant was only 4.7, failing to meet the technical requirements for low dielectric properties. Comparative Example 2, using hydroxyl-terminated polyphenylene ether-modified epoxy resin, achieved a dielectric constant of 4.5, but its glass transition temperature was only 159°C, failing to meet the technical requirements for high-temperature resistance and low dielectric properties. Comparative Example 3, using liquefied diphenylmethane diisocyanate and hydroxyl-terminated polyphenylene ether-modified epoxy resin, achieved a glass transition temperature of 168°C and a dielectric constant of 4.4, but its heat resistance and dielectric properties were still not as good as the composite material prepared in Example 1. This invention ultimately solves the technical problem of traditional epoxy prepregs being unable to simultaneously achieve high-temperature resistance and low dielectric properties, broadening the application of epoxy prepregs in composite materials fields such as high-frequency communication equipment.

[0065] Table 1. Properties of composite materials in different embodiments and comparative examples Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An epoxy resin-based prepreg possessing both high-temperature resistance and low dielectric properties, characterized in that, It is prepared from the following raw materials: 0.05-1 parts by weight of a first catalyst, 1-200 parts by weight of epoxy resin, 1-200 parts by weight of a diisocyanate compound, 0.05-1 parts by weight of a second catalyst, 1-20 parts by weight of a hydroxyl-terminated polyphenylene ether, 1-100 parts by weight of a liquid epoxy resin and 1-20 parts by weight of a latent curing system, wherein the diisocyanate compound contains a naphthalene ring, biphenyl or p-phenylene structure.

2. The epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to claim 1, characterized in that, The first catalyst includes at least one of imidazole, imidazole derivatives, Lewis acids, and base complexes.

3. The epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to claim 1, characterized in that, The epoxy resin includes at least one of bisphenol A glycidyl ether, bisphenol F glycidyl ether, bisphenol AD ​​glycidyl ether, liquid phenolic epoxy resin, and alicyclic epoxy resin.

4. The epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to claim 1, characterized in that, The diisocyanate compounds include at least one of 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, and terephthalic diisocyanate.

5. The epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to claim 1, characterized in that, The second catalyst includes at least one of triphenylphosphine and tetramethylammonium hydroxide.

6. The epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to claim 1, characterized in that, The latent curing system includes at least one of dicyandiamide, modified dicyandiamide, and urea derivatives.

7. The epoxy resin-based prepreg with both high temperature resistance and low dielectric properties according to claim 1, characterized in that, The epoxy resin-based prepreg further includes fibers; Preferably, the fiber comprises at least one of alkali-free glass fiber, high-strength glass fiber, and quartz fiber.

8. A method for preparing an epoxy resin-based prepreg possessing both high-temperature resistance and low dielectric properties, characterized in that, Includes the following steps: (1) In the presence of a first catalyst, epoxy resin and diisocyanate compound containing aromatic groups are reacted at 120-160℃ for 2-4 h, and double-terminated hydroxyl polyphenylene ether is added. In the presence of a second catalyst, the reaction is continued for 1-3 h to obtain high temperature resistant low dielectric epoxy resin, wherein the molar ratio of epoxy resin to diisocyanate compound is (3-6):

1. (2) Mix the high-temperature resistant low-dielectric epoxy resin with liquid epoxy resin and latent curing system to obtain a resin system for prepreg, wherein the liquid epoxy resin is 20-50 parts by weight relative to 100 parts by weight of the high-temperature resistant low-dielectric epoxy resin, and the latent curing system is 6-12 parts by weight. (3) The prepreg is prepared into a film using a resin system and then compounded with fibers to obtain the high-temperature resistant, low-dielectric epoxy resin prepreg.

9. The preparation method according to claim 8, characterized in that, In step (1), the amount of the first catalyst is 0.1-1% of the sum of the mass of the epoxy resin and the diisocyanate compound, the amount of the second catalyst is 0.1-1% of the sum of the mass of the epoxy resin and the diisocyanate compound, and the amount of the double-hydroxyl-terminated polyphenylene ether is 5-15% of the sum of the mass of the epoxy resin and the diisocyanate compound.

10. The application of the epoxy resin-based prepreg with both high temperature resistance and low dielectric properties as described in any one of claims 1-7 in high-frequency communication equipment.

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