Inorganic powder modified epoxy resin prepreg and preparation method thereof

Abstract

The present application relates to the technical field of high-performance electronic materials, and particularly relates to an inorganic powder modified epoxy resin prepreg for high-frequency high-speed printed circuit board and a preparation method thereof. The prepreg is prepared by impregnating a low-dielectric glass fiber cloth with a resin glue solution and drying, wherein the resin glue solution comprises an epoxy resin composition, a curing agent and an inorganic powder; the inorganic powder is hollow mesoporous silica nanospheres modified by p-chlorophenyl urea loading and hyperbranched polymer grafting. Through functional powder structure design and resin system optimization, the prepreg realizes low dielectric loss, high heat resistance, excellent interfacial bonding strength and good process stability in a synergistic manner, and is suitable for the preparation of high-frequency high-speed copper-clad boards.

Description

Technical Field

[0001] This invention relates to the field of high-performance electronic materials technology, and in particular to a modified epoxy resin glass cloth prepreg for high-frequency and high-speed printed circuit boards (PCBs) and its preparation method. Background Technology

[0002] Currently, the rapid development of technologies such as 5G mobile communication, artificial intelligence, high-performance computing, and autonomous driving has placed higher demands on the transmission, integrity, and system stability of core software signals. As a key extrusion material for printed circuit boards, copper-clad laminates must simultaneously meet the requirements of extremely low dielectric constant and dielectric loss factor to support high-frequency and high-speed signal transmission, and possess high glass transition temperature, excellent thermal delamination time, and long-term thermal stability to adapt to high power density and harsh operating conditions. This places extremely stringent requirements on material design.

[0003] To address these needs, current approaches primarily involve resin system modification, the addition of inorganic fillers, and optimization of reinforcing materials. However, these approaches also face technological bottlenecks. Resin system modification typically introduces rigid materials, leading to deterioration of node performance. Improving with inorganic fillers can compromise dielectric properties due to the tendency of nanofillers to aggregate and disperse. Regarding reinforcing materials, the dielectric properties of ordinary E-glass fiber cloth are insufficient for high-frequency requirements, while low-dielectric glass fiber cloth is prone to interfacial mismatch with the resin surface energy, resulting in weak interfacial bonding.

[0004] Therefore, the field needs a material that can overcome the inherent contradictions between various properties in existing material systems, and a prepreg material that can synergistically achieve ultra-low dielectric loss, high heat resistance and reliability, excellent interfacial bonding strength and good processing stability. Summary of the Invention

[0005] To address the technical challenge of achieving low dielectric properties, high heat resistance, excellent interfacial bonding, and good process stability in existing copper-clad laminate materials for high-frequency printed circuit boards in a synergistic manner, this application aims to provide an inorganic powder-modified epoxy resin prepreg and its preparation method.

[0006] In a first aspect, this application provides a prepreg sheet made of inorganic powder modified epoxy resin, using the following technical solution: An inorganic powder-modified epoxy resin prepreg sheet is prepared by impregnating a reinforcing material with a resin solution and then drying it. The resin solution comprises the following components by weight: 80-120 parts of epoxy resin composition; 1-10 parts of curing agent; 15-35 parts of inorganic powder; The inorganic powder is a hollow mesoporous silica nanosphere that has undergone dual surface modification by loading with p-chlorophenylurea and grafting with hyperbranched polyesteramine.

[0007] By employing the above technical solution, hollow mesoporous silica nanospheres are loaded with p-chlorophenylurea and further surface-grafted with hyperbranched polyesteramine, achieving dual surface modification of the inorganic powder. This inorganic powder is also introduced into the resin solution, thereby improving the overall performance of the prepreg.

[0008] Optionally, the epoxy resin composition comprises a first epoxy resin component and a second epoxy resin component; wherein the first epoxy resin component is selected from one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, and biphenyl type epoxy resin; and the second epoxy resin component is selected from one of fluorocycloalicyclo epoxy resin, fluorinated biphenyl type epoxy resin, and fluorinated naphthalene cyclooxygenated epoxy resin.

[0009] Optionally, the first epoxy resin component is a bisphenol A type epoxy resin, and the second epoxy resin component is a fluorocycloalicyclode epoxy resin.

[0010] Further optionally, based on 100 parts by weight of the total epoxy resin composition, the bisphenol A type epoxy resin is 60-70 parts by weight and the fluorocycloaliphatic epoxy resin is 30-40 parts by weight.

[0011] By employing the above technical solution, the resin matrix is ​​synergistically constructed using the first and second epoxy resin components, maintaining good processability and mechanical properties while reducing the dielectric constant and dielectric loss of the material. Further, by selecting bisphenol A type epoxy resin and fluorocycloaliphatic epoxy resin for compounding, and controlling the ratio range of the two, it is possible to ensure that the resin system has a high glass transition temperature and good interfacial bonding after curing, while further improving high-frequency signal transmission performance.

[0012] Optionally, the inorganic powder is prepared by a method comprising the following steps: a) Hollow mesoporous silica nanospheres are placed in a 5-15 wt% solution of p-chlorophenylurea and treated with an ultrasonic frequency of 20-60 kHz for 20-60 min, and then dried at 60-90 °C to obtain p-chlorophenylurea-loaded silica powder. b) Place the powder obtained in step a) in the silane coupling agent hydrolysate and react at 70-85℃ for 1-3 hours; c) Add hyperbranched polyesteramine to the system of step b), and continue the grafting reaction at 70-85°C for 0.5-2 hours. After the reaction, separate and dry to obtain the inorganic powder.

[0013] Further optionally, the method for preparing the inorganic powder includes the following steps: a) Hollow mesoporous silica nanospheres were placed in a 10 wt% solution of p-chlorophenylurea, treated with an ultrasonic frequency of 40 kHz for 30 min, and then dried at 80 °C for 4 h to obtain p-chlorophenylurea-loaded silica powder. b) Place the powder obtained in step a) in the silane coupling agent hydrolysate and stir the reaction at 75°C under nitrogen protection for 2 hours. c) Add hyperbranched polyesteramine to the system in step b), and continue the grafting reaction at 75°C for 1 hour. After the reaction, separate and dry to obtain the inorganic powder.

[0014] By adopting the above technical solution, inorganic powders are subjected to chlorophenylurea loading, silane coupling agent treatment, and hyperbranched polyesteramine grafting steps to construct a surface structure with interfacial enhancement effect. Further optimization of the concentration of chlorophenylurea solution, ultrasonic treatment, and post-treatment parameters helps to make the modification reaction more complete, thereby improving the compatibility and dispersibility of inorganic powders with epoxy resin matrix, and providing better interfacial bonding and performance consistency for the final prepreg.

[0015] Optionally, the hollow mesoporous silica nanospheres in step a) have a particle size of 50-150 nm; the silane coupling agent in step b) is selected from at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, the amount of the silane coupling agent is 0.5%-5% of the mass of the hollow mesoporous silica nanospheres, and the pH value of the hydrolysate is 4-5; the amount of hyperbranched polyesteramine added in step c) is 5-20% of the weight of the hollow mesoporous silica nanospheres.

[0016] Further optionally, the hollow mesoporous silica nanospheres in step a) have a particle size of 80-120 nm.

[0017] Further optionally, the silane coupling agent in step b) is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0018] Further optionally, in step c), the amount of hyperbranched polyesteramine added is 15% of the weight of the hollow mesoporous silica nanospheres.

[0019] By employing the above technical solution, the particle size of hollow mesoporous silica nanospheres is limited to the range of 50-150 nm, which helps to control their dispersibility and filling effect while maintaining a high specific surface area to facilitate surface modification. Further optimizing the particle size of the hollow mesoporous silica nanospheres to the range of 80-120 nm facilitates more uniform surface treatment during subsequent loading and grafting processes. The silane coupling agent and the specific pH of the hydrolysate effectively promote the hydrolysis and bonding of silanes on the powder surface, providing a stable and activated interface for subsequent grafting of hyperbranched polyesteramine. Further limiting the amount of hyperbranched polyesteramine added helps to form a moderate and uniform polymer graft layer on the powder surface, thereby improving its dispersion stability and interfacial compatibility in the resin matrix, and synergistically enhancing the bonding between the powder and the numerical material.

[0020] Optionally, based on 100 parts by weight of the epoxy resin composition, the inorganic powder is 20-25 parts by weight.

[0021] By adopting the above technical solution, the optimized content range can fully leverage the improving effect of inorganic fillers on dielectric and thermal properties, while avoiding the problems of decreased process performance and weakened interface caused by excessive filling.

[0022] Optionally, the curing agent is selected from at least one of dicyandiamide, sulfamic acid, substituted urea compounds, and imidazole derivatives; the weight of the curing agent is 1-10 parts based on 100 parts of the total weight of the epoxy resin composition.

[0023] Optionally, the curing agent is dicyandiamide; based on 100 parts by weight of the total epoxy resin composition, the dicyandiamide is 3-5 parts by weight.

[0024] By adopting the above technical solution, a range of curing agents is provided, and by further limiting the amount of curing agent, the cross-linking and curing reaction of the resin system can be fully carried out, avoiding incomplete curing due to insufficient amount or affecting the final performance of the material due to excessive amount.

[0025] Optionally, the resin adhesive further comprises a composite curing modifier selected from p-chlorophenylurea, 3-phenyl-1,1-dimethylurea, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea; the composite curing modifier is 0.5-2 parts by weight based on 100 parts of the total weight of the epoxy resin composition.

[0026] Optionally, the composite curing modifier is p-chlorophenylurea; based on 100 parts by weight of the total epoxy resin composition, the p-chlorophenylurea is 1.5 parts by weight.

[0027] By adopting the above technical solution, the introduction of composite curing regulators provides a more precise means of controlling the curing process of the resin system. The selected p-chlorophenylurea, as a regulator, can play a specific catalytic or retarding role in the curing system. Further limiting its dosage helps to effectively regulate the curing rate and reaction process without interfering with the main curing reaction, thereby optimizing the process window and improving the uniformity of the cured material. This achieves a good balance between the curing induction period and the reaction rate, and is also beneficial for obtaining prepreg materials with both good processability and excellent mechanical properties.

[0028] Optionally, the reinforcing material is selected from at least one of low dielectric constant glass fiber cloth, quartz fiber cloth, and aramid fiber cloth; wherein the low dielectric constant glass fiber cloth has a dielectric constant of not more than 4.0 and a thickness of 50-200 μm.

[0029] Further optionally, the reinforcing material is a low dielectric constant glass fiber cloth.

[0030] By adopting the above technical solutions, various types of reinforcing materials provide a variety of feasible structural support options for prepregs, helping to balance the mechanical properties, thermal stability, and joint performance of the materials. Further limiting the use to low-dielectric-constant glass fiber cloth and restricting the dielectric constant and thickness of this material can directly reduce the overall dielectric constant of the composite material, improving its applicability in high-frequency signal transmission. Simultaneously, the selected thickness range also facilitates good impregnation effects and dimensional stability of the prepreg during the lamination process.

[0031] Secondly, the application of inorganic powder-modified epoxy resin prepreg as described in the first aspect in the preparation of copper-clad laminates includes the following steps: (1) Lamination: The multilayer prepreg sheets are placed between two electrolytic copper foils and laminated to form a laminated structure; (2) Hot pressing curing: The laminated structure is placed in a hot press and cured at a pressure of 15-25 kg / cm². 2 Curing is carried out at a temperature of 180-220℃; (3) Post-processing: After curing, the copper-clad laminate is cooled and cut to obtain the copper-clad laminate.

[0032] Further, optionally, the preparation method includes the following steps: (1) Stacking: The 8 layers of prepreg are stacked between two electrolytic copper foils to form a symmetrical stacked structure; (2) Hot pressing curing: The symmetrical laminated structure is placed in a hot press and cured at a pressure of 20 kg / cm². 2 Curing is carried out at a temperature of 200℃; (3) Post-processing: After curing, the copper-clad laminate is cooled and cut to obtain the copper-clad laminate.

[0033] By adopting the above technical solution, the prepreg obtained by the present invention can be used for the preparation of high-frequency and high-speed copper-clad laminates. While maintaining excellent process adaptability, it has low dielectric loss, high heat resistance and excellent interface bonding, meeting the stringent requirements of PCB materials in current fields such as 5G communication and high-performance computing.

[0034] In summary, this application includes at least one of the following beneficial technical effects: 1. By designing and introducing inorganic powders, the compatibility and dispersion stability of the powders and resin matrix are significantly improved, and the agglomeration of nanoparticles is effectively suppressed. This reduces the dielectric constant and dielectric loss while improving the interfacial bonding strength of the material. 2. The blending system of bisphenol A epoxy resin and fluorocycloaliphatic epoxy resin is adopted, which synergistically reduces the polarity and water absorption of the resin system, giving the prepreg excellent dielectric properties and high-frequency signal transmission stability. 3. By optimizing the proportions and process parameters of each group, a comprehensive improvement was achieved in the prepreg's performance in terms of low dielectric loss, high glass transition temperature, excellent thermal delamination time, and good process adaptability, making it suitable for the preparation of high-performance copper-clad laminates in fields such as high-frequency and high-speed PCBs. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to comparative examples and embodiments.

[0036] The raw materials used in the preparation examples and embodiments are all commercially available products. Specific information about some of the raw materials is as follows: Bisphenol A type epoxy resin, EEW=185-195 g / eq; Fluorocycloaliphatic epoxy resin, viscosity 8000-16000 mPa·s, epoxy value 0.14-0.16, fluorine content 37-45wt%; Hollow mesoporous silica nanospheres, with a particle size of 80-120 nm, were provided by CAS Science & Technology Co., Ltd. Hyperbranched polyesteramine (HBPA), product number N103, molecular weight 1900-2200, amino number 12-16 mol, provided by Wuhan Hyperbranched Resin Technology Co., Ltd. Dicyandiamide, CAS 461-58-5, content ≥99%; p-Chlorophenylurea, CAS 140-38-5, content ≥98%; Low dielectric fiber cloth, dielectric constant 3.7, elongation at break 4.6%, melting point 1700℃; Methyl isobutyl ketone (MIBK), CAS 493-52-7, purity ≥99%.

[0037] Preparation Example 1 1. Take 100g of hollow mesoporous silica nanospheres with a particle size of 80-120nm, add them to 500mL of 10wt% p-chlorophenylurea acetone solution, sonicate at 40 kHz for 30 minutes, and dry the resulting mixture under reduced pressure at 80℃ for 4 hours to obtain p-chlorophenylurea-loaded silica powder. 2. Mix ethanol and deionized water at a mass ratio of 85:10, add 5 parts of KH-792 type silane coupling agent, add acetic acid to adjust the pH of the system to 4.5, let stand for 30 minutes to hydrolyze, and obtain hydrolysate; 3. Add the silica powder obtained in step 1 to the hydrolysate obtained in step 2, stir and react at 75°C under nitrogen protection for 2 hours, add 15g of hyperbranched polyesteramine to the system, and continue to react at 75°C for 1 hour. After the reaction is completed, centrifuge the mixture and wash it three times with ethanol. Dry the obtained solid in a vacuum oven at 80°C for 6 hours to obtain functionalized hollow mesoporous silica nanosphere powder.

[0038] Preparation Example 2 The difference from Preparation Example 1 is that the hollow mesoporous silica nanospheres have a particle size of 50-80 nm, an 8 wt% p-chlorophenylurea acetone solution is used, the amount of hyperbranched polyesteramine added is 10 g, and the silane coupling agent used is KH-550 type silane coupling agent.

[0039] Preparation Example 3 The difference from Preparation Example 1 is that a 15 wt% p-chlorophenylurea-toluene mixed solution (p-chlorophenylurea to toluene mass ratio of 1:1) was used for loading treatment, ultrasonication for 1 hour, and reflux stirring at 85°C for 2 hours followed by drying. The amount of hyperbranched polyesteramine added was 20 g, the reaction temperature was 78°C, and the reaction time was 45 minutes.

[0040] Preparation Example 4 The difference from Preparation Example 1 is that the hollow mesoporous silica nanospheres have a particle size of 120-150 nm, the concentration of the p-chlorophenylurea acetone solution is 12 wt%, the silane coupling agent is KH-560, the hydrolysis pH is adjusted to 4.0, the amount of hyperbranched polyesteramine added is 12 g, and a heat treatment step of 80°C for 1 hour is added in the post-reaction stage.

[0041] Example 1

[0042] 1. In a reaction vessel, add 60 parts of bisphenol A type epoxy resin and 30 parts of methyl isobutyl ketone, and stir at 300 rpm at room temperature until the resin is completely dissolved to form a homogeneous solution A. 2. Slowly add 40 parts of fluorocyclohexane epoxy resin to solution A, and stir the mixture continuously at 60°C for 2 hours to obtain a homogeneous and transparent blended resin solution B; 3. Add 25 parts of the functionalized powder obtained in Preparation Example 1 to the blended resin solution B, first perform shear dispersion treatment at 5000 rpm for 20 minutes, then perform ultrasonic dispersion, and ultrasonic treatment at 800 W and 20 kHz for 30 minutes until the D90 particle size of the particles in the slurry is ≤200 nm, to obtain nanocomposite colloid C. 4. After the composite adhesive C cools to room temperature, add 4 parts of dicyandiamide and mix at 200 rpm for 40 minutes to ensure full dispersion. Finally, filter the adhesive through a 10 μm filter to remove agglomerates and impurities to obtain the resin adhesive.

[0043] Example 2

[0044] The difference between this embodiment and Example 1 is that the amount of functionalized powder obtained in Example 1 added is 35 parts.

[0045] Example 3

[0046] The difference between this embodiment and Embodiment 1 is that the amount of bisphenol A type epoxy resin added is 70 parts by weight, the amount of fluorocycloaliphatic epoxy resin added is 30 parts by weight, and 1.5 parts by weight of p-chlorophenylurea is added as a composite curing modifier in step 4.

[0047] Example 4

[0048] The difference between this embodiment and Embodiment 1 is that the amount of functionalized hollow mesoporous silica nanopowder added is 15 parts by weight, and 1.0 part by weight of hyperbranched polyesteramine is added as a dispersion stabilizing agent in step 3.

[0049] Example 5

[0050] The difference between this embodiment and Example 1 is that the functionalized hollow mesoporous silica nanospheres used were prepared according to the method of Preparation Example 2.

[0051] Example 6

[0052] The difference between this embodiment and Example 1 is that the functionalized hollow mesoporous silica nanospheres used were prepared according to the method of Preparation Example 3.

[0053] Example 7

[0054] The difference between this embodiment and Example 1 is that the functionalized hollow mesoporous silica nanospheres used were prepared according to the method of Preparation Example 4.

[0055] Comparative Example 1 The difference between this comparative example and Example 1 is that the filler used is ordinary hollow mesoporous silica nanospheres without any treatment.

[0056] Comparative Example 2 The difference between this comparative example and Example 1 is that the filler used is only treated with KH-792 silane coupling agent for conventional surface treatment, without infiltration of p-chlorophenylurea or grafting of hyperbranched polyesteramine.

[0057] Comparative Example 3 The difference between this comparative example and Example 1 is that the resin matrix is ​​entirely made of bisphenol A type epoxy resin (i.e., without the addition of fluorocycloaliphatic epoxy resin), while the other components and processes are the same as in Example 1.

[0058] Example 8

[0059] To verify the comprehensive performance of the inorganic powder-modified epoxy resin prepregs provided by each scheme, the resin solutions prepared in the above embodiments and comparative examples were coated, cured, and then laminated with low-dielectric glass fiber cloth to form prepregs. These prepregs were then laminated to form copper-clad laminates. The preparation methods are as follows: 1. Stacking: The 8 prepreg sheets obtained in each embodiment and comparative example are stacked with 2 electrolytic copper foils, adopting a symmetrical structure of copper foil (1 sheet) - prepreg sheet (8 sheets) - copper foil (1 sheet); 2. Place the assembled structure in a vacuum hot press at a pressure of 20 kg / cm². 2 The resin is heated in stages at 200℃ and kept at that temperature for 90 minutes to fully cure it and form a strong bond with the copper foil. 3. After curing, cool to room temperature and cut to obtain copper-clad laminate.

[0060] The resulting copper-clad laminate will undergo the following key performance tests: 1. Dielectric loss Df and dielectric constant Dk: Tested according to IPC TM-650 2.5.5.13 test method; 2. Glass transition temperature Tg: Tested according to IPC TM-650 2.4.24.1 (TMA method); 3. Thermal delamination time (T-260 / T-288): According to IPC TM-650 2.4.24.1, the time for material delamination at 260℃ and 288℃ is determined; 4. Copper foil peel strength: Tested according to IPC TM-650 2.4.8 test method.

[0061] The performance tests of copper-clad laminates prepared using the prepregs obtained in Examples 1-7 and Comparative Examples 1-3 are shown in Table 1 below: Table 1

[0062] Example 1, as the basic formulation, combines a functionalized powder with a bisphenol A / fluorocycloaliphatic epoxy resin blend system using a specific surface treatment. This results in good and balanced overall performance in terms of dielectric properties, heat resistance, and interfacial bonding. The p-chlorophenylurea loaded in the functionalized powder and the grafted hyperbranched polyesteramine effectively improve the dispersibility and interfacial compatibility of the filler in the resin, thereby contributing to lower dielectric loss and higher peel strength.

[0063] Example 2 further increased the amount of functionalized powder added compared to Example 1. The results showed that while maintaining excellent heat resistance, the dielectric constant and loss factor were further reduced, and the interfacial bonding strength was slightly improved, indicating that appropriately increasing the proportion of functionalized filler helps to enhance the dielectric properties and interfacial bonding effect of the system.

[0064] Example 3 adjusted the resin matrix ratio, increasing the proportion of bisphenol A epoxy resin and introducing p-chlorophenylurea as a composite curing modifier. This approach showed superior performance in terms of glass transition temperature while maintaining good delamination resistance and interfacial bonding, indicating that controlling the polarity of the resin system and its curing behavior has a positive impact on improving the thermal stability of the material.

[0065] Example 4 reduced the amount of functionalized powder but added hyperbranched polyesteramine as a dispersion stabilizer. This measure effectively improved the process stability of the resin solution. However, due to the reduced loading of functionalized filler, the dielectric properties and heat resistance of the final cured material were somewhat weakened compared to other examples with high filler ratios, but its key performance indicators were still significantly better than the comparative examples.

[0066] Examples 5-7 show functionalized powders prepared using different methods. The powder used in Example 6 exhibits the best dielectric properties and high interfacial bonding strength, demonstrating that the uniformity of the powder surface treatment and the functional group grafting efficiency have a crucial impact on the dielectric and interfacial properties of the final composite material. Examples 5 and 7 also show superior stability and compatibility compared to the comparative examples in different performance dimensions.

[0067] Comparative Example 1 uses untreated ordinary powder, which has significantly higher dielectric loss, poorer heat resistance and interfacial bonding, and obvious sedimentation during the process. This indicates that unmodified powder is difficult to disperse effectively in resin and form a good bond with the matrix.

[0068] Comparative Example 2 only used conventional silane coupling agents to treat the powder, without loading p-chlorophenylurea or grafting with hyperbranched polymers. Although its performance was better than Comparative Example 1, it was still significantly lower than the examples, especially in terms of dielectric loss and interface strength, indicating that a single surface treatment method cannot achieve a synergistic improvement in dielectric, interface, and process stability.

[0069] Comparative Example 3 used only bisphenol A type epoxy resin without introducing fluorocycloalicylic epoxy resin. This scheme showed the weakest performance in terms of dielectric properties, heat resistance, and interfacial bonding, indicating that the introduction of fluorocycloalicylic epoxy resin plays an irreplaceable role in reducing system polarity and improving high-frequency dielectric properties and thermal stability.

[0070] In summary, this application achieves high dispersion of powder in resin, significantly enhanced interfacial bonding, effective optimization of dielectric properties, and comprehensive improvement of process stability by precisely controlling the surface characteristics of functionalized powder, the polarity of the resin matrix and the curing system, as well as the ratio between functional components. The performance differences among the various embodiments further confirm the crucial influence of the synergistic effect and ratio balance of the components in the material design on the final product performance.

[0071] Of course, the above description is only a specific embodiment of this application and is not intended to limit the scope of the invention. All equivalent changes or modifications made in accordance with the features and principles described in the claims of this invention should be included in the scope of the claims of this invention.

Claims

1. An inorganic powder-modified epoxy resin prepreg sheet, prepared by impregnating reinforcing materials with resin adhesive followed by drying, characterized in that... The resin solution comprises the following components by weight: 80-120 parts of epoxy resin composition; 1-10 parts of curing agent; 15-35 parts of inorganic powder; The inorganic powder is a hollow mesoporous silica nanosphere that has undergone dual surface modification by loading with p-chlorophenylurea and grafting with hyperbranched polyesteramine.

2. The inorganic powder-modified epoxy resin prepreg sheet according to claim 1, characterized in that, The epoxy resin composition comprises a first epoxy resin component and a second epoxy resin component; wherein the first epoxy resin component is selected from one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, and biphenyl type epoxy resin; and the second epoxy resin component is selected from one of fluorocycloalicyclo epoxy resin, fluorinated biphenyl type epoxy resin, and fluorinated naphthalene cyclooxygenated epoxy resin.

3. The inorganic powder-modified epoxy resin prepreg sheet according to claim 2, characterized in that, Based on 100 parts by weight of the total epoxy resin composition, the bisphenol A type epoxy resin is 60-70 parts by weight, and the fluorocycloaliphatic epoxy resin is 30-40 parts by weight.

4. The inorganic powder modified epoxy resin prepreg sheet according to claim 1, characterized in that, The inorganic powder is prepared by a method comprising the following steps: a) Hollow mesoporous silica nanospheres are placed in a 5-15 wt% solution of p-chlorophenylurea and treated with an ultrasonic frequency of 20-60 kHz for 20-60 min, and then dried at 60-90 °C to obtain p-chlorophenylurea-loaded silica powder. b) Place the powder obtained in step a) in the silane coupling agent hydrolysate and react at 70-85℃ for 1-3 hours; c) Add hyperbranched polyesteramine to the system of step b), and continue the grafting reaction at 70-85°C for 0.5-2 hours. After the reaction, separate and dry to obtain the inorganic powder.

5. The inorganic powder-modified epoxy resin prepreg sheet according to claim 4, characterized in that, In step a), the hollow mesoporous silica nanospheres have a particle size of 50-150 nm; in step b), the silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and the amount of the silane coupling agent is 0.5%-5% of the mass of the hollow mesoporous silica nanospheres, and the pH value of the hydrolysate is 4-5; in step c), the amount of hyperbranched polyesteramine added is 5-20% of the weight of the hollow mesoporous silica nanospheres.

6. The inorganic powder-modified epoxy resin prepreg sheet according to claim 5, characterized in that, Based on a total weight of 100 parts of the epoxy resin composition, the inorganic powder comprises 20-25 parts by weight.

7. The inorganic powder modified epoxy resin prepreg sheet according to claim 1, characterized in that, The curing agent is selected from at least one of dicyandiamide, sulfamic acid, substituted urea compounds, and imidazole derivatives; the curing agent is 1-10 parts by weight based on 100 parts of the total weight of the epoxy resin composition.

8. The inorganic powder modified epoxy resin prepreg sheet according to claim 7, characterized in that, The resin adhesive further comprises a composite curing modifier, which is selected from one of p-chlorophenylurea, 3-phenyl-1,1-dimethylurea, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea; based on 100 parts by weight of the total epoxy resin composition, the composite curing modifier is 0.5-2 parts by weight.

9. The inorganic powder-modified epoxy resin prepreg sheet according to claim 1, characterized in that, The reinforcing material is selected from one of low dielectric constant glass fiber cloth, quartz fiber cloth, and aramid fiber cloth; wherein the low dielectric constant glass fiber cloth has a dielectric constant of not more than 4.0 and a thickness of 50-200 μm.

10. The application of an inorganic powder-modified epoxy resin prepreg as described in any one of claims 1-9 in the preparation of copper-clad laminates, characterized in that, The method for preparing the copper-clad laminate includes the following steps: (1) Lamination: The multilayer prepreg sheets are placed between two electrolytic copper foils and laminated to form a laminated structure; (2) Hot pressing curing: The laminated structure is placed in a hot press and cured at a pressure of 15-25 kg / cm². 2 Curing is carried out at a temperature of 180-220℃; (3) Post-processing: After curing, the copper-clad laminate is cooled and cut to obtain the copper-clad laminate.

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