Preparation method of high-frequency heat-resistant epoxy resin-based copper-clad plate

Abstract

The invention belongs to the technical field of production of high-frequency heat-resistant epoxy resin-based copper-clad plates, and particularly relates to a preparation method of a high-frequency heat-resistant epoxy resin-based copper-clad plate, which comprises the following steps: synthesizing a dynamic network prepolymer, mixing cucurbituril [8] (CB [8]) and a carboxylic acid functionalized ferrocene derivative, and self-assembling in a buffer solution to obtain the high-frequency heat-resistant epoxy resin-based copper-clad plate. The preparation method comprises the following steps: carrying out polymerization on a host-guest compound to form a dynamic reversible host-guest compound, and then carrying out prepolymerization on the host-guest compound and a tetrafunctional maleimide monomer under UV illumination to form a rigid host network and retain the reversible characteristic of a dynamic bond. Through double-network design, namely, fluorine-containing epoxy resin and maleimide form a rigid main network, a dynamic polyrotaxane network (reversible bond) realizes high-temperature stress dissipation so as to effectively improve the TG temperature and realize high heat resistance, and secondly, GO aerogel and perfluoropolyether are filled to form a porous low-dielectric structure, so that the dielectric constant of the composite material is reduced, and the composite material has good heat resistance. And the transmission loss and the signal attenuation are effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of the production of high-frequency heat-resistant epoxy resin-based copper clad laminates, and particularly relates to a preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate. Background Art

[0002] A high-frequency heat-resistant epoxy resin-based copper clad laminate is an electronic material that uses epoxy resin as a base material and electroplates a copper thin film on its surface through a copper cladding process. It has excellent electrical conductivity and heat resistance, and can provide stable signal transmission in a high-frequency environment and ensure reliability in a high-temperature environment.

[0003] However, there are still two defects in the existing epoxy resin-based copper clad laminates. One is the problem of signal attenuation and transmission loss at high frequencies. The other is that it is prone to thermal decomposition and failure at high temperatures, leading to the failure of the entire circuit.

[0004] In view of this, the present invention provides a preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate. Summary of the Invention

[0005] To achieve the above object, the present invention provides the following technical solution: A preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate, comprising the following steps:

[0006] S1: Synthesis of dynamic network prepolymer;

[0007] Mix cucurbit[8] (CB[8]) with a carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH), self-assemble in a buffer solution to form a dynamic reversible host-guest complex, and then pre-polymerize the host-guest complex with a tetrafunctional maleimide monomer under UV light irradiation to form a rigid main network, retaining the reversible characteristics of the dynamic bonds;

[0008] Apply a gradient electric field of 0→5 kV / mm on the surface of the copper foil to make the dynamic network prepolymer gradient-distribute along the electric field direction. Mix the fluorinated epoxy resin with the dynamic network prepolymer, and achieve chemical bonding through a phase transfer catalytic reaction (tetraethylammonium chloride as a catalyst) to form a double network structure;

[0009] S2: Preparation of nano-aerogel reinforcing phase;

[0010] Mix a graphene oxide (GO) dispersion with carbon nanofibers (CNF), freeze-dry and then treat with supercritical CO2 to obtain a three-dimensional porous aerogel with a porosity > 90% and a pore size of 10 - 50 nm. Aminate the aerogel skeleton with 3-aminopropyltriethoxysilane to enhance the interfacial bonding strength with the resin. Inject low-viscosity perfluoropolyether into the aerogel pores in a vacuum chamber, preheat at 60 °C and then raise the temperature to 120 °C for curing for 2 hours to form a "pore-PFPE" double low-dielectric system;

[0011] S3: Composite structure forming and lamination;

[0012] Using an electric field-assisted 3D printing technique, alternately stack gradient resin layers and GO aerogel sheets (with a thickness of 10 μm), where the thickness of each resin layer is 50 μm and the spacing between aerogel layers is 200 μm, to form a vertical heat conduction path. Pre-cure at 80 °C for 1 hour to initially crosslink the dynamic network and fix the gradient structure. Stack the composite sheet with copper foil and place it in a vacuum hot press for stepwise temperature increase curing and then annealing.

[0013] Preferably, as a preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate of the present invention, in the S1, cucurbit[8]uril (CB[8]) and carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH) are mixed in a molar ratio of 1:2;

[0014] The fluorinated epoxy resin is 3-(pentafluoroethyl)phenol condensate resin, which is mixed with the dynamic network prepolymer in a mass ratio of 6:4.

[0015] Preferably, as a preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate of the present invention, in the S1, the UV light irradiation condition is 365 nm, 50 mW / cm 2 。

[0016] Preferably, as a preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate of the present invention, in the S2, the concentration of the graphene oxide dispersion is 5 mg / mL, and the mass ratio of carbon nanofibers is 1 wt%;

[0017] The vacuum degree of the vacuum chamber is 10 -3 Pa.

[0018] Preferably, as a preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate of the present invention, the stepwise temperature increase curing and then annealing in the S3 include: Stage 1: 120 °C / 2 MPa / 1 h to promote resin flow and fill the interface; Stage 2: 180 °C / 5 MPa / 2 h to complete the dynamic network reorganization and maleimide crosslinking; Stage 3: 240 °C / 8 MPa / 1 h to ensure complete curing of the PFPE and resin interface; Anneal at 250 °C for 4 hours to release internal stress and optimize the molecular chain arrangement.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] Through a dual-network design, namely, a rigid main network is formed by a fluorinated epoxy resin and maleimide, and a dynamic polyrotaxane network (reversible bonds) realizes high-temperature stress dissipation, so as to effectively increase the TG temperature and achieve high heat resistance. Secondly, through the filling of GO aerogel and perfluoropolyether, a porous low-dielectric structure is formed, thereby reducing its dielectric constant and effectively reducing transmission loss and signal attenuation. Detailed implementation mode

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the attached solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0022] The present invention relates to a preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate, comprising the following steps:

[0023] S1: Synthesis of dynamic network prepolymer; Cucurbit[8] (CB[8]) and carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH) are mixed and self-assembled in a buffer solution to form a dynamic reversible host-guest complex. Then, the host-guest complex and a tetrafunctional maleimide monomer are pre-polymerized under UV light to form a rigid main network, retaining the reversible characteristics of the dynamic bonds; A gradient electric field of 0→5 kV / mm is applied on the surface of the copper foil to make the dynamic network prepolymer gradient-distribute along the electric field direction. The fluorinated epoxy resin and the dynamic network prepolymer are mixed, and chemical bonding is achieved through a phase transfer catalytic reaction (tetraethylammonium chloride as the catalyst) to form a dual-network structure;

[0024] S2: Preparation of nano-aerogel reinforcing phase; A dispersion of graphene oxide (GO) and carbon nanofibers (CNF) are mixed, freeze-dried and then treated with supercritical CO2 to obtain a three-dimensional porous aerogel with a porosity > 90% and a pore size of 10-50 nm. The aerogel skeleton is aminated with 3-aminopropyltriethoxysilane to enhance the interfacial bonding strength with the resin. In a vacuum chamber, low-viscosity perfluoropolyether is injected into the pores of the aerogel, preheated at 60 °C and then cured at 120 °C for 2 hours to form a "pore-PFPE" dual low-dielectric system;

[0025] S3: Molding and lamination of the composite structure; Using an electric field-assisted 3D printing technology, the gradient resin layer and GO aerogel sheets (thickness 10 μm) are alternately stacked (each resin layer has a thickness of 50 μm and the spacing between aerogel layers is 200 μm) to form a vertical heat conduction path. Pre-cure at 80 °C for 1 hour to preliminarily crosslink the dynamic network and fix the gradient structure. Stack the composite sheets and copper foil, and place them in a vacuum hot press for staged heating and curing and then annealing.

[0026] Specifically, take 1.0 - 2.0 g of cucurbit[8]uril (CB[8]), dissolve it in 100 - 200 mL of phosphate buffer solution (PBS) with pH = 8, ultrasonically disperse for 30 - 60 minutes, add 2.0 - 4.0 g of carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH), and magnetically stir for 4 - 5 hours to form a host-guest complex (CB[8]-Ferrocene). Mix 5.0 - 10.0 g of tetra-functional maleimide monomer (such as BMI-70) with the host-guest complex solution, add photoinitiator TPO (0.5 wt%), stir evenly, pour the mixture into a polytetrafluoroethylene mold, and place it in an ultraviolet curing box (wavelength 365 nm, intensity 50 mW / cm 2 ) and irradiate for 15 - 30 minutes to form a dynamic network prepolymer gel; take 6.0 - 12.0 g of fluorinated epoxy resin (such as FX-3F type) and mix it with 4.0 - 8.0 g of the dynamic network prepolymer gel, add phase transfer catalyst tetraethylammonium chloride (0.1 wt%), stir at 60 °C for 2 - 3 hours to form a uniform resin matrix. Install parallel electrode plates on the surface of a copper foil (thickness 18 μm) with an electrode spacing of 10 mm, and connect an adjustable high-voltage power supply. Coat the resin matrix on the copper foil (wet film thickness 100 μm), apply a gradient electric field (0 → 5 kV / mm, linearly varying along the length direction of the copper foil), and maintain the electric field for 30 minutes to make the dynamic network components migrate to the high-electric field region, forming a gradient structure with a dynamic network ratio of 30% → 5%; mix the graphene oxide (GO) dispersion (5 mg / mL) with 1 wt% carbon nanofibers (CNF), ultrasonically treat for 1 - 3 hours, inject the mixture into a mold, quickly freeze it in liquid nitrogen, and then transfer it to a freeze dryer (-50 °C, 24 h) to obtain a porous skeleton. Place the freeze-dried skeleton in a supercritical CO2 device (temperature 31 °C, pressure 7.4 MPa) and process for 6 hours to obtain a GO aerogel with a porosity > 90%. Immerse the GO aerogel in a 3-aminopropyltriethoxysilane ethanol solution (5% v / v) and react at 60 °C for 4 hours. After washing and drying, obtain an amino-functionalized aerogel; place the amino-functionalized aerogel in a vacuum impregnation tank, evacuate to 10 -3Inject low-viscosity perfluoropolyether (Krytox GPL 105), preheat at 60°C for 30 minutes, pressurize to 5 MPa and maintain for 2 hours. Transfer the impregnated aerogel to an oven and cure at 120°C for 2 hours to bond PFPE to the aerogel skeleton through hydrogen bonds. Use an electric field-assisted 3D printer with a nozzle temperature of 80°C and a printing speed of 5 mm / s to print the first layer of gradient resin matrix (thickness 50 μm) on the copper foil surface. Then lay a PFPE-filled GO aerogel sheet (thickness 10 μm) on the gradient resin matrix, and repeat the alternating stacking (resin layer 50 μm + aerogel layer 10 μm) until the total thickness is controlled within 400 - 500 μm. After that, preheat at 80°C for 1 hour to preliminarily crosslink the resin. Place the laminated structure and the copper foil in alignment in a stainless steel mold and perform three-stage hot pressing under a vacuum of ≤50 Pa to avoid bubble residues. The hot pressing parameters include: the first stage of hot pressing at 120°C / 2 MPa / 1 - 2 h; the second stage of hot pressing at 180°C / 5 MPa / 1 - 2 h; the third stage of hot pressing at 240°C / 8 MPa / 1 - 2 h. Place the laminated copper-clad laminate in a nitrogen-protected annealing furnace, anneal at 250°C for 4 - 5 hours with a heating rate of 2°C / min to eliminate internal stress, and then treat the surface of the copper-clad laminate with a plasma cleaner (power 200 W, Ar gas atmosphere) to improve the adhesion between the copper foil and the resin.

[0027] The present invention will be further described below in conjunction with specific embodiments:

[0028] Example 1:

[0029] Take 1.0 g of cucurbit[8]uril (CB[8]), dissolve it in 100 mL of phosphate buffer solution (PBS) with pH = 8, ultrasonically disperse for 30 minutes, add 2.0 g of carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH), and magnetically stir for 4 hours to form a host-guest complex (CB[8]-Ferrocene). Mix 5.0 g of tetra-functional maleimide monomer (such as BMI-70) with the host-guest complex solution, add a photoinitiator TPO (0.5 wt%), stir evenly, pour the mixture into a polytetrafluoroethylene mold, and place it in an ultraviolet curing box (wavelength 365 nm, intensity 50 mW / cm 2)Irradiate for 15 minutes to form a dynamic network prepolymer gel; take 6.0 g of fluorinated epoxy resin (such as FX-3F type) and mix it with 4.0 g of the dynamic network prepolymer gel, add the phase transfer catalyst tetraethylammonium chloride (0.1 wt%), stir at 60 °C for 2 hours to form a uniform resin matrix; install parallel electrode plates on the surface of a copper foil (with a thickness of 18 μm), with a spacing of 10 mm, and connect an adjustable high-voltage power supply. Coat the resin matrix on the copper foil (wet film thickness 100 μm), apply a gradient electric field (0 → 5 kV / mm, linearly varying along the length direction of the copper foil), and maintain the electric field for 30 minutes to make the dynamic network components migrate to the high-electric-field region, forming a gradient structure with a dynamic network proportion of 30% → 5%; mix the graphene oxide (GO) dispersion liquid (5 mg / mL) with 1 wt% carbon nanofibers (CNF), ultrasonically treat for 1 hour, inject the mixed liquid into a mold, quickly freeze it in liquid nitrogen, and then transfer it to a freeze dryer (-50 °C, 24 h) to obtain a porous skeleton. Place the freeze-dried skeleton in a supercritical CO2 device (temperature 31 °C, pressure 7.4 MPa) and process for 6 hours to obtain a GO aerogel with a porosity > 90%. Immerse the GO aerogel in a 3-aminopropyltriethoxysilane ethanol solution (5% v / v), react at 60 °C for 4 hours, wash and dry to obtain an aminated aerogel; place the aminated aerogel in a vacuum impregnation tank, evacuate to 10 -3 Pa, inject low-viscosity perfluoropolyether (Krytox GPL 105), preheat at 60 °C for 30 minutes, pressurize to 5 MPa and maintain for 2 hours. Transfer the impregnated aerogel to an oven and cure at 120 °C for 2 hours to make the PFPE bind to the aerogel skeleton through hydrogen bonds; use an electric field-assisted 3D printer with a nozzle temperature of 80 °C and a printing speed of 5 mm / s to print the first layer of the gradient resin matrix (thickness 50 μm) on the surface of the copper foil, and then lay a PFPE-filled GO aerogel sheet (thickness 10 μm) on the gradient resin matrix. Repeat the alternating stacking (resin layer 50 μm + aerogel layer 10 μm) until the total thickness is controlled within 400 μm, and then preheat at 80 °C for 1 hour to preliminarily crosslink the resin; place the laminated structure and the copper foil in alignment in a stainless steel mold and perform three-stage hot pressing with a vacuum degree ≤ 50 Pa to avoid residual bubbles. The hot pressing parameters include: the first-stage hot pressing at 120 °C / 2 MPa / 1 h; the second-stage hot pressing at 180 °C / 5 MPa / 1 h; the third-stage hot pressing at 240 °C / 8 MPa / 1 h; place the laminated copper clad laminate in a nitrogen-protected annealing furnace, anneal at 250 °C for 4 - 5 hours with a heating rate of 2 °C / min to eliminate internal stress, and then treat the surface of the copper clad laminate with a plasma cleaner (power 200 W, Ar gas atmosphere) to improve the adhesion between the copper foil and the resin, obtaining a high-frequency heat-resistant copper clad laminate.

[0030] Measure the dielectric constant (Dk) of the high-frequency heat-resistant copper clad laminate at 10 GHz using a vector network analyzer (such as Keysight N5221B).

[0031] Conduct a DMA (Dynamic Mechanical Analysis) test on the high-frequency heat-resistant copper clad laminate. The test parameters are: frequency 1 Hz, temperature range 25 - 400 °C, to confirm the Tg (glass transition temperature).

[0032] Example 2:

[0033] Take 1.5 g of cucurbit[8] (CB[8]), dissolve it in 150 mL of phosphate buffer solution (PBS) with pH = 8, ultrasonically disperse for 45 minutes, add 3 g of carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH), and stir magnetically for 4 hours to form a host-guest complex (CB[8]-Ferrocene). Mix 7 g of tetra-functional maleimide monomer (such as BMI-70) with the host-guest complex solution, add photoinitiator TPO (0.5 wt%), stir evenly, pour the mixture into a polytetrafluoroethylene mold, and place it in an ultraviolet curing box (wavelength 365 nm, intensity 50 mW / cm 2 ) and irradiate for 20 minutes to form a dynamic network prepolymer gel; take 8 g of fluorinated epoxy resin (such as FX-3F type) and mix it with 6 g of the dynamic network prepolymer gel, add phase transfer catalyst tetraethylammonium chloride (0.1 wt%), stir at 60 °C for 3 hours to form a uniform resin matrix. Install parallel electrode plates on the surface of a copper foil (thickness 18 μm) with a spacing of 10 mm, and connect an adjustable high-voltage power supply. Coat the resin matrix on the copper foil (wet film thickness 100 μm), apply a gradient electric field (0 → 5 kV / mm, linearly varying along the length direction of the copper foil), and maintain the electric field for 30 minutes to make the dynamic network components migrate to the high-electric-field region, forming a gradient structure with a dynamic network ratio of 30% → 5%; mix the graphene oxide (GO) dispersion (5 mg / mL) with 1 wt% carbon nanofibers (CNF), ultrasonically treat for 1 - 3 hours, inject the mixture into a mold, quickly freeze it in liquid nitrogen, and then transfer it to a freeze dryer (-50 °C, 24 h) to obtain a porous skeleton. Place the freeze-dried skeleton in a supercritical CO2 device (temperature 31 °C, pressure 7.4 MPa) and process for 6 hours to obtain a GO aerogel with a porosity > 90%. Immerse the GO aerogel in a 3-aminopropyltriethoxysilane ethanol solution (5% v / v), react at 60 °C for 4 hours, wash and dry to obtain an aminated aerogel; place the aminated aerogel in a vacuum impregnation tank, evacuate to 10 -3Inject Pa with low-viscosity perfluoropolyether (Krytox GPL105), preheat at 60 °C for 30 minutes, pressurize to 5 MPa and maintain for 2 hours, transfer the impregnated aerogel to an oven, cure at 120 °C for 2 hours to bind PFPE to the aerogel skeleton through hydrogen bonds; use an electric field-assisted 3D printer with a nozzle temperature of 80 °C and a printing speed of 5 mm / s to print the first layer of gradient resin matrix (thickness 50 μm) on the copper foil surface, then lay a PFPE-filled GO aerogel sheet (thickness 10 μm) on the gradient resin matrix, and repeat the alternating stacking (resin layer 50 μm + aerogel layer 10 μm) until the total thickness is controlled at 400 μm, then preheat at 80 °C for 1 hour to preliminarily crosslink the resin; place the laminated structure and the copper foil in alignment in a stainless steel mold and perform three-stage hot pressing with a vacuum degree ≤ 50 Pa to avoid residual bubbles. The hot pressing parameters include: the first-stage hot pressing at 120 °C / 2 MPa / 1.5 h; the second-stage hot pressing at 180 °C / 5 MPa / 1.5 h; the third-stage hot pressing at 240 °C / 8 MPa / 1.5 h; place the laminated copper clad laminate in a nitrogen-protected annealing furnace, anneal at 250 °C for 4 hours with a heating rate of 2 °C / min to eliminate internal stress, and then treat the surface of the copper clad laminate with a plasma cleaner (power 200 W, Ar gas atmosphere) to improve the adhesion between the copper foil and the resin, obtaining a high-frequency heat-resistant copper clad laminate.

[0034] Use a vector network analyzer (such as Keysight N5221B) to measure the dielectric constant (Dk) of the high-frequency heat-resistant copper clad laminate at 10 GHz.

[0035] Conduct DMA (dynamic mechanical analysis) tests on the high-frequency heat-resistant copper clad laminate. The test parameters are: frequency 1 Hz, temperature range 25 - 400 °C, to confirm the Tg (glass transition temperature).

[0036] Example 3:

[0037] Take 2.0 g of cucurbit[8]uril (CB[8]), dissolve it in 200 mL of phosphate buffer solution (PBS) with pH = 8, ultrasonically disperse for 60 minutes, add 4.0 g of carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH), magnetically stir for 5 hours to form a host-guest complex (CB[8]-Ferrocene), mix 10.0 g of tetrafunctional maleimide monomer (such as BMI-70) with the host-guest complex solution, add a photoinitiator TPO (0.5 wt%), stir evenly, pour the mixture into a polytetrafluoroethylene mold, and place it in an ultraviolet curing box (wavelength 365 nm, intensity 50 mW / cm 2) Irradiate for 30 minutes to form a dynamic network prepolymer gel; take 12.0 g of fluorinated epoxy resin (such as FX-3F type) and mix it with 8.0 g of the dynamic network prepolymer gel, add a phase transfer catalyst tetraethylammonium chloride (0.1 wt%), stir at 60 °C for 3 hours to form a uniform resin matrix. Install parallel electrode plates on the surface of a copper foil (thickness 18 μm) with a spacing of 10 mm, and connect an adjustable high-voltage power supply. Coating the resin matrix on the copper foil (wet film thickness 100 μm), apply a gradient electric field (0→5 kV / mm, linearly varying along the length direction of the copper foil), and maintain the electric field for 30 minutes to make the dynamic network components migrate to the high-electric-field region, forming a gradient structure with a dynamic network proportion of 30%→5%; mix a graphene oxide (GO) dispersion (5 mg / mL) with 1 wt% carbon nanofibers (CNF), ultrasonically treat for 3 hours, inject the mixture into a mold, place it in liquid nitrogen for rapid freezing, and then transfer it to a freeze dryer (-50 °C, 24 h) to obtain a porous skeleton. Place the freeze-dried skeleton in a supercritical CO2 device (temperature 31 °C, pressure 7.4 MPa) for 6 hours to obtain a GO aerogel with a porosity > 90%. Immerse the GO aerogel in a 3-aminopropyltriethoxysilane ethanol solution (5% v / v), react at 60 °C for 4 hours, wash and dry to obtain an aminated aerogel; place the aminated aerogel in a vacuum impregnation tank, evacuate to 10 -3 Pa, inject a low-viscosity perfluoropolyether (Krytox GPL 105), preheat at 60 °C for 30 minutes, pressurize to 5 MPa and maintain for 2 hours. Transfer the impregnated aerogel to an oven and cure at 120 °C for 2 hours to make the PFPE bind to the aerogel skeleton through hydrogen bonds; use an electric field-assisted 3D printer with a nozzle temperature of 80 °C and a printing speed of 5 mm / s to print the first layer of the gradient resin matrix (thickness 50 μm) on the surface of the copper foil, and then lay a GO aerogel sheet filled with PFPE (thickness 10 μm) on the gradient resin matrix, and repeat the alternating stacking (resin layer 50 μm + aerogel layer 10 μm) until the total thickness is controlled at 500 μm, and then preheat at 80 °C for 1 hour to preliminarily crosslink the resin; place the laminated structure and the copper foil in alignment in a stainless steel mold and perform three-stage hot pressing with a vacuum degree ≤ 50 Pa to avoid air bubble residues. The hot pressing parameters include: the first-stage hot pressing at 120 °C / 2 MPa / 2 h; the second-stage hot pressing at 180 °C / 5 MPa / 2 h; the third-stage hot pressing at 240 °C / 8 MPa / 2 h; place the laminated copper clad laminate in a nitrogen-protected annealing furnace, anneal at 250 °C for 4 - 5 hours with a heating rate of 2 °C / min to eliminate internal stress, and then treat the surface of the copper clad laminate with a plasma cleaner (power 200 W, Ar gas atmosphere) to improve the adhesion between the copper foil and the resin, obtaining a high-frequency heat-resistant copper clad laminate.

[0038] Measure the dielectric constant (Dk) of the high-frequency heat-resistant copper clad laminate at 10 GHz using a vector network analyzer (such as Keysight N5221B).

[0039] Conduct a DMA (Dynamic Mechanical Analysis) test on the high-frequency heat-resistant copper clad laminate. The test parameters are: frequency 1 Hz, temperature range 25 - 400 °C, to confirm the Tg (glass transition temperature).

[0040] The preparation method of the prior art is as follows: Weigh 10 - 50 parts of epoxy resin (such as bisphenol A type epoxy resin or DCPD type epoxy resin), 3 - 20 parts of curing agent (such as DDS or dicyandiamide), 10 - 30 parts of inorganic filler (talc powder / silica powder), and 10 - 60 parts of flame retardant (aluminum hydroxide / phosphorus-based flame retardant) according to the formula, add them to a solvent (acetone / butanone), and mechanically stir at 60 - 80 °C for 2 hours to form a uniform resin glue solution. Control the solid content at 50 - 70%. Immerse an alkali-free glass fiber cloth (model 1035 or 2116) into the resin glue solution, control the impregnation time at 1 - 2 minutes to ensure a resin content of 40 - 70%, pre-cure in an oven at 150 - 170 °C for 4 - 7 minutes to form a prepreg (resin flow 15 - 35%). Stack 6 - 8 prepregs, cover both sides with 18 - 35 μm copper foil, place them in a stainless steel mold, and in a vacuum press at 170 - 220 °C, pressure 2 - 8 MPa, time 120 - 180 minutes, raise the temperature in stages to eliminate internal stress, and finally anneal at 150 - 200 °C for 1 - 2 hours to improve dimensional stability.

[0041] Prepare Comparative Example 1 and Comparative Example 2 using the above preparation method of the prior art as follows:

[0042] Comparative Example 1:

[0043] Weigh 10 parts of epoxy resin (such as bisphenol A type epoxy resin or DCPD type epoxy resin), 3 parts of curing agent (such as DDS or dicyandiamide), 10 parts of inorganic filler (talc powder / silica powder), and 10 parts of flame retardant (aluminum hydroxide / phosphorus-based flame retardant) according to the formula, add them to a solvent (acetone / butanone), and mechanically stir at 60 °C for 2 hours to form a uniform resin glue solution with a solid content of 53%. Immerse an alkali-free glass fiber cloth (model 1035) into the resin glue solution, control the impregnation time at 1 minute with a resin content of 42%, pre-cure in an oven at 150 °C for 4 minutes to form a prepreg (resin flow 18%). Stack 6 prepregs, cover both sides with 18 μm copper foil, place them in a stainless steel mold, and in a vacuum press at 170 °C, pressure 2 MPa, time 120 minutes, raise the temperature in stages to eliminate internal stress, and finally anneal at 150 °C for 1 hour.

[0044] Measure the dielectric constant (Dk) of the high-frequency heat-resistant copper clad laminate at 10 GHz using a vector network analyzer (such as Keysight N5221B);

[0045] Conduct a DMA (Dynamic Mechanical Analysis) test on the high-frequency heat-resistant copper clad laminate. The test parameters are: frequency 1 Hz, temperature range 25 - 400 °C, and confirm the Tg (glass transition temperature).

[0046] Comparative Example 2:

[0047] Weigh 50 parts of epoxy resin (such as bisphenol A epoxy resin or DCPD epoxy resin), 20 parts of curing agent (such as DDS or dicyandiamide), 30 parts of inorganic filler (talc powder / silica powder), and 60 parts of flame retardant (aluminum hydroxide / phosphorus-based flame retardant) according to the formula. Add them to a solvent (acetone / butanone), and mechanically stir at 80 °C for 2 hours to form a uniform resin glue solution. Control the solid content at 64%. Immerse the E-glass fiber cloth (model 2116) in the resin glue solution, control the impregnation time at 2 minutes, ensure the resin content is 64%, and pre-cure in an oven at 170 °C for 7 minutes to form a prepreg (resin flow 31%). Stack 8 prepregs, cover both sides with 18 μm copper foil, place them in a stainless steel mold, and in a vacuum press at 220 °C, pressure 2 MPa, and time 180 minutes, gradually increase the temperature in stages to eliminate internal stress, and finally anneal at 200 °C for 2 hours.

[0048] Measure the dielectric constant (Dk) of the high-frequency heat-resistant copper clad laminate at 10 GHz using a vector network analyzer (such as Keysight N5221B);

[0049] Conduct a DMA (Dynamic Mechanical Analysis) test on the high-frequency heat-resistant copper clad laminate. The test parameters are: frequency 1 Hz, temperature range 25 - 400 °C, and confirm the Tg (glass transition temperature).

[0050] The test results are as follows:

[0051] Dielectric constant / 10 GHz Glass transition temperature Example 1 2.3 335℃ Example 2 2.5 320℃ Example 3 2.2 350℃ Comparative Example 1 3.9 215℃ Comparative Example 2 3.6 260℃

[0052] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a high-frequency heat-resistant epoxy resin-based copper clad laminate, characterized in that, It includes the following steps: S1: Synthesis of dynamic network prepolymer; Mix cucurbit[8]uril (CB[8]) with carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH), self-assemble in a buffer solution to form a dynamic reversible host-guest complex, and then pre-polymerize the host-guest complex with a tetrafunctional maleimide monomer under UV light to form a rigid main network, retaining the reversible characteristics of the dynamic bonds; Apply a gradient electric field of 0→5 kV / mm on the surface of the copper foil to make the dynamic network prepolymer distribute in a gradient along the electric field direction. Mix the fluorinated epoxy resin with the dynamic network prepolymer and achieve chemical bonding through a phase transfer catalytic reaction (tetraethylammonium chloride as the catalyst) to form a double network structure; S2: Preparation of nano-aerogel reinforcing phase; Mix the graphene oxide (GO) dispersion with carbon nanofibers (CNF), freeze-dry and then treat with supercritical CO2 to obtain a three-dimensional porous aerogel with a porosity > 90% and a pore size of 10 - 50 nm. Aminate the aerogel skeleton with 3-aminopropyltriethoxysilane to enhance the interfacial bonding strength with the resin. Inject low-viscosity perfluoropolyether into the aerogel pores in a vacuum chamber, preheat at 60 °C and then raise the temperature to 120 °C and cure for 2 hours to form a "pore-PFPE" double low-dielectric system; S3: Molding and lamination of the composite structure; Adopt an electric field-assisted 3D printing technology to alternately stack gradient resin layers and GO aerogel sheets (thickness 10 μm) (each resin layer thickness is 50 μm, and the spacing between aerogel layers is 200 μm) to form a vertical heat conduction path. Pre-cure at 80 °C for 1 hour to initially crosslink the dynamic network and fix the gradient structure. Stack the composite sheets with the copper foil and place them in a vacuum hot press to cure and anneal in stages by raising the temperature.

2. The preparation method of the high-frequency heat-resistant epoxy resin-based copper clad laminate according to claim 1, characterized in that: In the S1, the mixing of cucurbit[8]uril (CB[8]) and carboxylic acid-functionalized ferrocene derivative (Ferrocene-COOH) is carried out in a molar ratio of 1:2; The fluorinated epoxy resin is 3-(pentafluoroethyl)phenol condensate resin, and it is mixed with the dynamic network prepolymer in a mass ratio of 6:

4.

3. The preparation method of the high-frequency heat-resistant epoxy resin-based copper clad laminate according to claim 1, wherein: The UV light condition in S1 is 365 nm, 50 mW / cm 2 .

4. The preparation method of the high-frequency heat-resistant epoxy resin-based copper clad laminate according to claim 1, wherein: In the S2, the concentration of the graphene oxide dispersion is 5 mg / mL, and the mass ratio of carbon nanofibers is 1 wt%; The vacuum degree of the vacuum chamber is 10 -3 Pa.

5. The preparation method of the high-frequency heat-resistant epoxy resin-based copper clad laminate according to claim 1, wherein: The annealing after curing in stages in the S3 includes Stage 1: 120 °C / 2 MPa / 1 h to promote the resin to flow and fill the interface; Stage 2: 180 °C / 5 MPa / 2 h to complete the dynamic network reorganization and maleimide crosslinking; Stage 3: 240 °C / 8 MPa / 1 h to ensure complete curing of the PFPE and resin interface; Anneal at 250 °C for 4 hours to release internal stress and optimize the molecular chain arrangement.