A low-dielectric copper clad laminate reinforced with alumina filler and its preparation method

Abstract

This invention relates to the field of copper clad laminate (CCL) manufacturing technology, specifically to a low-dielectric CCL reinforced with alumina filler and its preparation method. By selecting the composition and ratio of the resin solution, this invention enables the CCL to possess excellent dielectric properties, thermal conductivity, heat resistance, and flame retardancy. Its key features include: the resin solution contains spherical Al2O3 filler with high heat resistance, which increases the heat resistance of the CCL; the spherical particle morphology also meets the requirements of high filling rate and high packing density. Furthermore, this invention treats the filler: first, the spherical Al2O3 is modified, and then the modified Al2O3 is further modified with hyperbranched cyclotriphosphazene, allowing the three flame-retardant elements Al, P, and N to work synergistically, thereby exhibiting superior flame-retardant properties; in addition, the addition of cyanate ester resin and bisphenol A type epoxy resin can effectively reduce the dielectric constant and dielectric loss of the CCL.

Description

Technical Field

[0001] This invention relates to the field of copper clad laminate manufacturing technology, specifically to a low-dielectric copper clad laminate reinforced with alumina filler and its preparation method. Background Technology

[0002] Miniaturization is one of the main development directions of modern electronic and photonic devices. The intense heat generated by these components cannot be dissipated, leading to decreased device performance and even reduced lifespan. Therefore, with the miniaturization and centralization of devices, flame retardancy has become increasingly urgent. Currently, flame-retardant copper-clad laminates are also an important area of ​​development. The flame-retardant capability of these laminates depends on the flame-retardant properties of the resin, and the key technology lies in solving the flame-retardant properties of the resin dielectric layer. However, currently, the resin dielectric layer has a high C and H content, and some even contain O, resulting in poor fire resistance and flame retardancy. It is impossible to simultaneously achieve low dielectric constant and low dielectric loss while ensuring good heat resistance and flame retardancy.

[0003] To overcome the shortcomings of the prior art, the present invention provides an alumina-filled reinforced low-dielectric copper clad laminate and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an alumina-filled reinforced low-dielectric copper clad laminate and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] An alumina-filled reinforced low-dielectric copper-clad laminate and its preparation method, comprising the following steps:

[0007] Step 1: Mix filler, resin, solvent, silane coupling agent, surfactant, curing agent, and accelerator under high-speed stirring to obtain resin solution. The stirring speed is 800-1500 rpm.

[0008] Step 2: Arrange electronic-grade glass fibers in the resin solution and impregnate both sides, bake at 150℃-200℃ for 6-10 minutes, and then cool to obtain a semi-cured sheet;

[0009] Step 3: Stack the prepreg sheets, and cover both sides of the stacked prepreg sheets with a layer of copper foil to obtain the board material;

[0010] Step 4: Press the stacked boards, then insulate them to obtain precast panels.

[0011] Step 5: Cut the precast board to obtain a low-dielectric copper clad laminate reinforced with alumina filler.

[0012] In a more optimized manner, in step one, the resin is a cyanate ester resin and a bisphenol A type epoxy resin, the solvent is acetone and toluene, the surfactant is a fluorocarbon surfactant, the curing agent is a phenolic resin, and the accelerator is dimethylimidazole.

[0013] In a more optimized manner, the preparation steps of the filler in step one are as follows:

[0014] S1: Preparation of branched polymer: Under a nitrogen atmosphere, hexachlorocyclotriphosphazene and 4,4'-diaminodiphenylmethane were added to anhydrous toluene. After the solid was completely dissolved, triethylamine was added. The mixture was stirred at 70-80℃ for 10-12 h. After the reaction was completed, the mixture was cooled to room temperature. The reactants were then washed with ethanol and dried under vacuum at 45-55℃ for 8-10 h to obtain the branched polymer.

[0015] S2: Preparation of modified Al2O3: A mixture of spherical Al2O3 and aqueous ethanol solution was ultrasonically dispersed for 15-25 min to prepare dispersion A. Then, a mixture of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and aqueous ethanol solution was ultrasonically dispersed for 15-25 min to prepare dispersion B. Dispersion B was added dropwise to dispersion A and kept at 70-80℃ for 12-14 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3.

[0016] S3: Preparation of filler: N,N-dimethylformamide solution, triethylamine, branched polymer prepared in S1 and modified Al2O3 prepared in S2 are mixed and heated to 130-150℃ under nitrogen protection for 6-8 hours. After the reaction is completed, the mixture is washed with anhydrous ethanol and dried.

[0017] In a more optimized manner, in step one, by weight, there are 40-60 parts filler, 60-80 parts cyanate ester resin, 40-50 parts bisphenol A type epoxy resin, 10-40 parts solvent, 0.5-3.0 parts silane coupling agent, 0.05-0.1 parts surfactant, 3-9 parts curing agent, and 0.05-0.50 parts accelerator.

[0018] Ideally, in step two, the adhesive content of the prepared semi-cured sheet is 50wt%-70wt%.

[0019] In a more optimized manner, in step four, the pressing temperature is 150℃-220℃, and the pressing pressure per unit area is 1Mpa-3Mpa.

[0020] In a more optimized manner, in step four, the heat preservation temperature is 180℃-220℃, the heat preservation time is 60min-90min, and the pressure per unit area during the heat preservation stage is 2Mpa-4Mpa.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0022] By employing the above-mentioned technical solutions, the addition of cyanate ester resin and bisphenol A type epoxy resin is beneficial for preparing copper-clad laminates with low dielectric constants, giving the copper-clad laminates excellent dielectric properties. However, these resins have extremely low thermal conductivity, which cannot meet the requirements of rapid heat transfer. The addition of spherical Al2O3 filler can meet the requirements of high thermal conductivity, and the spherical particle morphology can also meet the requirements of high filling rate and high packing density. The preparation of filler in this invention is based on the modification of spherical Al2O3 to obtain modified Al2O3 with epoxy groups, and then the addition of branched polymers to introduce a phosphorus-nitrogen flame retardant system on the surface of the modified spherical Al2O3, so that the three flame retardant elements Al, P, and N work synergistically to exert highly efficient flame retardant performance. The main reaction principle is as follows: On the one hand, phosphorus generates chemically stable compounds such as ammonium metaphosphate during combustion, providing the matrix with certain physical protection and barrier effects; on the other hand, nitrogen-containing structures release non-flammable gases such as N, NH3, and CO2 during thermal decomposition, diluting the oxygen concentration in the air to achieve flame retardancy. Therefore, the synergistic effect of the three can effectively improve the flame retardancy efficiency of the polymer matrix. In addition, the branched polymer has a typical core-shell structure, which can disperse spherical Al2O3 particles into a porous three-dimensional structure, avoiding particle collisions and aggregation, and giving the filler good dispersibility and stability. Therefore, the copper-clad laminate prepared by impregnation with the resin solution has good dielectric properties, heat resistance, and flame retardancy. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Spherical Al2O3, with a particle size of 2-50μm, was purchased from Jiangsu Lianrui New Materials Co., Ltd.; cyanate ester resin, TA1000S, was purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.; bisphenol A epoxy resin, YQ-Z020, was purchased from Lingshou Yuanquan Chemical Building Materials Store; phenolic resin curing agent, CA-t-31, was purchased from Henan Chiao Trading Co., Ltd.; silane coupling agent, Si-69, was purchased from Shandong Huachen New Materials Co., Ltd.; fluorocarbon surfactant, FS8600, was purchased from Jinan Jinbang Environmental Protection Technology Co., Ltd.; copper foil, KX-0250, with a thickness of 50μm, was purchased from Dongguan Kaishi Packaging Materials Co., Ltd.

[0025] Example 1

[0026] Step 1: Preparation of packing material

[0027] S1: Preparation of branched polymer: Under a nitrogen atmosphere, 4.09 g of hexachlorocyclotriphosphazene and 24.09 g of 4,4'-diaminodiphenylmethane were added to 130 mL of anhydrous toluene. After the solids were completely dissolved, 1.34 mL of triethylamine was added. The mixture was stirred at 80 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature. The reactants were then washed with ethanol and dried under vacuum at 55 °C for 10 h to obtain the branched polymer.

[0028] S2: Preparation of modified Al2O3: 4.08 g of spherical Al2O3 and an aqueous ethanol solution were ultrasonically dispersed for 25 min to prepare dispersion A. Then, 1.79 mL of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and an aqueous ethanol solution were ultrasonically dispersed for 25 min to prepare dispersion B. Dispersion B was added dropwise to dispersion A and kept at 80 °C for 14 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3.

[0029] S3: Preparation of filler: 180 mL of N,N-dimethylformamide solution, 2.0 mL of triethylamine, the branched polymer prepared in S1 and the modified Al2O3 prepared in S2 were mixed and heated to 150 °C under nitrogen protection for 8 h. After the reaction, the mixture was washed with anhydrous ethanol and dried.

[0030] Step 2: Preparation of Resin Solution

[0031] By weight, 60 parts filler, 80 parts cyanate ester resin, 50 parts bisphenol A epoxy resin, 40 parts solvent, 3.0 parts silane coupling agent, 0.15 parts surfactant, 9 parts curing agent, 0.50 parts accelerator, and 30 parts flame retardant were mixed under high-speed stirring to obtain a resin solution at a stirring rate of 1500 rpm.

[0032] Step 3: Preparation of Prepreg

[0033] Electronic-grade glass fibers are arranged in the resin solution and impregnated on both sides. Then, they are baked at 200°C for 10 minutes and cooled to obtain a semi-cured sheet with a resin content of 70 wt%.

[0034] Step 4: Preparation of the board material

[0035] Two prepreg sheets are stacked together, and a layer of copper foil is applied to both sides of the stacked prepreg sheets to obtain the board material.

[0036] Step 5: Preparation of Precast Slabs

[0037] The stacked boards are pressed at a temperature of 220℃ and a pressure of 3 MPa per unit area. After pressing, the boards are kept at 220℃ for 90 minutes with a pressure of 4 MPa per unit area to obtain the precast boards.

[0038] Step 6: Cut the precast board to obtain a low-dielectric copper-clad laminate reinforced with alumina filler.

[0039] Example 2

[0040] Step 1: Preparation of packing material

[0041] S1: Preparation of branched polymer: Under a nitrogen atmosphere, 4.09 g of hexachlorocyclotriphosphazene and 24.09 g of 4,4'-diaminodiphenylmethane were added to 130 mL of anhydrous toluene. After the solids were completely dissolved, 1.34 mL of triethylamine was added. The mixture was stirred at 75 °C for 11 h. After the reaction was completed, it was cooled to room temperature. The reactants were then washed with ethanol and dried under vacuum at 50 °C for 9 h to obtain the branched polymer.

[0042] S2: Preparation of modified Al2O3: 4.08 g of spherical Al2O3 and an aqueous ethanol solution were ultrasonically dispersed for 20 min to prepare dispersion A. Then, 1.79 mL of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and an aqueous ethanol solution were ultrasonically dispersed for 20 min to prepare dispersion B. Dispersion B was added dropwise to dispersion A and kept at 75 °C for 13 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3.

[0043] S3: Preparation of filler: 180 mL of N,N-dimethylformamide solution, 2.0 mL of triethylamine, the branched polymer prepared in S1 and the modified Al2O3 prepared in S2 were mixed and heated to 140 °C under nitrogen protection for 7 h. After the reaction, the mixture was washed with anhydrous ethanol and dried.

[0044] Step 2: Preparation of Resin Solution

[0045] By weight, 60 parts filler, 80 parts cyanate ester resin, 50 parts bisphenol A epoxy resin, 40 parts solvent, 3 parts silane coupling agent, 0.15 parts surfactant, 9 parts curing agent, 0.5 parts accelerator, and 30 parts flame retardant were mixed under high-speed stirring to obtain a resin solution at a stirring rate of 1150 rpm.

[0046] Step 3: Preparation of Prepreg

[0047] Electronic-grade glass fibers are arranged in the resin solution and impregnated on both sides. Then, they are baked at 175°C for 8 minutes and cooled to obtain a semi-cured sheet with a resin content of 70 wt%.

[0048] Step 4: Preparation of the board material

[0049] Two prepreg sheets are stacked together, and a layer of copper foil is applied to both sides of the stacked prepreg sheets to obtain the board material.

[0050] Step 5: Preparation of Precast Slabs

[0051] The stacked boards are pressed at a temperature of 185℃ and a pressure of 2 MPa per unit area. After pressing, they are kept at 200℃ for 75 minutes with a pressure of 3 MPa per unit area to obtain the precast board.

[0052] Step 6: Cut the precast board to obtain a low-dielectric copper-clad laminate reinforced with alumina filler.

[0053] Example 3

[0054] Step 1: Preparation of packing material

[0055] S1: Preparation of branched polymer: Under a nitrogen atmosphere, 4.09 g of hexachlorocyclotriphosphazene and 24.09 g of 4,4'-diaminodiphenylmethane were added to 130 mL of anhydrous toluene. After the solids were completely dissolved, 1.34 mL of triethylamine was added. The mixture was stirred at 70 °C for 10 h. After the reaction was completed, it was cooled to room temperature. The reactants were then washed with ethanol and dried under vacuum at 45 °C for 8 h to obtain the branched polymer.

[0056] S2: Preparation of modified Al2O3: 4.08 g of spherical Al2O3 and an aqueous ethanol solution were ultrasonically dispersed for 15 min to prepare dispersion A. Then, 1.79 mL of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and an aqueous ethanol solution were ultrasonically dispersed for 15 min to prepare dispersion B. Dispersion B was added dropwise to dispersion A and kept at 70 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3.

[0057] S3: Preparation of filler: 180 mL of N,N-dimethylformamide solution, 2 mL of triethylamine, the branched polymer prepared in S1 and the modified Al2O3 prepared in S2 were mixed and heated to 130 °C under nitrogen protection for 6 h. After the reaction, the mixture was washed with anhydrous ethanol and dried.

[0058] Step 2: Preparation of Resin Solution

[0059] By weight, 60 parts filler, 80 parts cyanate ester resin, 50 parts bisphenol A epoxy resin, 40 parts solvent, 3 parts silane coupling agent, 0.15 parts surfactant, 9 parts curing agent, 0.5 parts accelerator, and 30 parts flame retardant were mixed under high-speed stirring at a stirring rate of 800 rpm to obtain a resin solution.

[0060] Step 3: Preparation of Prepreg

[0061] Electronic-grade glass fibers are arranged in the resin solution and impregnated on both sides. Then, they are baked at 150°C for 6 minutes and then cooled to obtain a semi-cured sheet with a resin content of 70 wt%.

[0062] Step 4: Preparation of the board material

[0063] Two prepreg sheets are stacked together, and a layer of copper foil is applied to both sides of the stacked prepreg sheets to obtain the board material.

[0064] Step 5: Preparation of Precast Slabs

[0065] The stacked boards are pressed at a temperature of 150℃ and a pressure of 1 MPa per unit area. After pressing, they are kept at 180℃ for 60 minutes with a pressure of 2 MPa per unit area to obtain the precast board.

[0066] Step 6: Cut the precast board to obtain a low-dielectric copper-clad laminate reinforced with alumina filler.

[0067] Example 4: The preparation of branched polymers is omitted from step one: filler preparation. The rest is the same as in Example 1. The specific steps are as follows:

[0068] Step 1: Preparation of packing material

[0069] Dispersion A was prepared by ultrasonically dispersing a mixture of 4.08 g spherical Al2O3 and an aqueous ethanol solution for 25 min. Then, dispersion B was prepared by ultrasonically dispersing a mixture of 1.79 mL γ-(2,3-epoxypropoxy)propyltrimethoxysilane and an aqueous ethanol solution for 25 min. Dispersion B was added dropwise to dispersion A and kept at 80 °C for 14 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3.

[0070] Step 2: Preparation of Resin Solution

[0071] By weight, 60 parts filler, 80 parts cyanate ester resin, 50 parts bisphenol A epoxy resin, 40 parts solvent, 3.0 parts silane coupling agent, 0.15 parts surfactant, 9 parts curing agent, 0.50 parts accelerator, and 30 parts flame retardant were mixed under high-speed stirring to obtain a resin solution at a stirring rate of 1500 rpm.

[0072] Step 3: Preparation of Prepreg

[0073] Electronic-grade glass fibers are arranged in the resin solution and impregnated on both sides. Then, they are baked at 200°C for 10 minutes and cooled to obtain a semi-cured sheet with a resin content of 70 wt%.

[0074] Step 4: Preparation of the board material

[0075] Two prepreg sheets are stacked together, and a layer of copper foil is applied to both sides of the stacked prepreg sheets to obtain the board material.

[0076] Step 5: Preparation of Precast Slabs

[0077] The stacked boards are pressed at a temperature of 220℃ and a pressure of 3 MPa per unit area. After pressing, the boards are kept at 220℃ for 90 minutes with a pressure of 4 MPa per unit area to obtain the precast boards.

[0078] Step 6: Cut the precast board to obtain a low-dielectric copper-clad laminate reinforced with alumina filler.

[0079] Example 5: In step two, the amount of filler used in the preparation of the resin solution is halved, while the rest is the same as in Example 1. The specific steps are as follows:

[0080] Step 1: Preparation of packing material

[0081] S1: Preparation of branched polymer: Under a nitrogen atmosphere, 4.09 g of hexachlorocyclotriphosphazene and 24.09 g of 4,4'-diaminodiphenylmethane were added to 130 mL of anhydrous toluene. After the solids were completely dissolved, 1.34 mL of triethylamine was added. The mixture was stirred at 80 °C for 12 h. After the reaction was completed, it was cooled to room temperature. The reactants were then washed with ethanol and dried under vacuum at 55 °C for 10 h to obtain the branched polymer.

[0082] S2: Preparation of modified Al2O3: 4.08 g of spherical Al2O3 and an aqueous ethanol solution were ultrasonically dispersed for 25 min to prepare dispersion A. Then, 1.79 mL of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and an aqueous ethanol solution were ultrasonically dispersed for 25 min to prepare dispersion B. Dispersion B was added dropwise to dispersion A and kept at 80 °C for 14 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3.

[0083] S3: Preparation of filler: 180 mL of N,N-dimethylformamide solution, 2.0 mL of triethylamine, the branched polymer prepared in S1 and the modified Al2O3 prepared in S2 were mixed and heated to 150 °C under nitrogen protection for 8 h. After the reaction, the mixture was washed with anhydrous ethanol and dried.

[0084] Step 2: Preparation of Resin Solution

[0085] By weight, 30 parts filler, 80 parts cyanate ester resin, 50 parts bisphenol A epoxy resin, 40 parts solvent, 3.0 parts silane coupling agent, 0.15 parts surfactant, 9 parts curing agent, 0.50 parts accelerator, and 15 parts flame retardant were mixed under high-speed stirring to obtain a resin solution at a stirring rate of 1500 rpm.

[0086] Step 3: Preparation of Prepreg

[0087] Electronic-grade glass fibers are arranged in the resin solution and impregnated on both sides. Then, they are baked at 200°C for 10 minutes and cooled to obtain a semi-cured sheet with a resin content of 70 wt%.

[0088] Step 4: Preparation of the board material

[0089] Two prepreg sheets are stacked together, and a layer of copper foil is applied to both sides of the stacked prepreg sheets to obtain the board material.

[0090] Step 5: Preparation of Precast Slabs

[0091] The stacked boards are pressed at a temperature of 220℃ and a pressure of 3 MPa per unit area. After pressing, the boards are kept at 220℃ for 90 minutes with a pressure of 4 MPa per unit area to obtain the precast boards.

[0092] Step 6: Cut the precast board to obtain a low-dielectric copper-clad laminate reinforced with alumina filler.

[0093] Example 6: In step two, the amount of filler used in the preparation of the resin solution is increased by half, while the rest is the same as in Example 1. The specific steps are as follows:

[0094] Step 1: Preparation of packing material

[0095] S1: Preparation of branched polymer: Under a nitrogen atmosphere, 4.09 g of hexachlorocyclotriphosphazene and 24.09 g of 4,4'-diaminodiphenylmethane were added to 130 mL of anhydrous toluene. After the solids were completely dissolved, 1.34 mL of triethylamine was added. The mixture was stirred at 80 °C for 12 h. After the reaction was completed, it was cooled to room temperature. The reactants were then washed with ethanol and dried under vacuum at 55 °C for 10 h to obtain the branched polymer.

[0096] S2: Preparation of modified Al2O3: 4.08 g of spherical Al2O3 and an aqueous ethanol solution were ultrasonically dispersed for 25 min to prepare dispersion A. Then, 1.79 mL of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and an aqueous ethanol solution were ultrasonically dispersed for 25 min to prepare dispersion B. Dispersion B was added dropwise to dispersion A and kept at 80 °C for 14 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3.

[0097] S3: Preparation of filler: 180 mL of N,N-dimethylformamide solution, 2.0 mL of triethylamine, the branched polymer prepared in S1 and the modified Al2O3 prepared in S2 were mixed and heated to 150 °C under nitrogen protection for 8 h. After the reaction, the mixture was washed with anhydrous ethanol and dried.

[0098] Step 2: Preparation of Resin Solution

[0099] By weight, 90 parts filler, 80 parts cyanate ester resin, 50 parts bisphenol A epoxy resin, 40 parts solvent, 3.0 parts silane coupling agent, 0.15 parts surfactant, 9 parts curing agent, 0.50 parts accelerator, and 15 parts flame retardant were mixed under high-speed stirring to obtain a resin solution at a stirring rate of 1500 rpm.

[0100] Step 3: Preparation of Prepreg

[0101] Electronic-grade glass fibers are arranged in the resin solution and impregnated on both sides. Then, they are baked at 200°C for 10 minutes and cooled to obtain a semi-cured sheet with a resin content of 70 wt%.

[0102] Step 4: Preparation of the board material

[0103] Two prepreg sheets are stacked together, and a layer of copper foil is applied to both sides of the stacked prepreg sheets to obtain the board material.

[0104] Step 5: Preparation of Precast Slabs

[0105] The stacked boards are pressed at a temperature of 220℃ and a pressure of 3 MPa per unit area. After pressing, the boards are kept at 220℃ for 90 minutes with a pressure of 4 MPa per unit area to obtain the precast boards.

[0106] Step 6: Cut the precast board to obtain a low-dielectric copper-clad laminate reinforced with alumina filler.

[0107] Testing and experimentation:

[0108] The copper-clad laminates prepared in Examples 1 to 6 were subjected to performance tests. The limiting oxygen index (LOI) is the volume fraction of oxygen at which a polymer can just sustain combustion in a mixture of oxygen and nitrogen; it is an index characterizing the combustion behavior of a material. It is expressed as the volume percentage of oxygen. A high LOI indicates that the material is not easily combustible, while a low LOI indicates that the material is easily combustible. The dielectric constant D of the copper-clad laminate was then tested using the parallel plate capacitance method. K and dielectric loss factor D f， The resonant frequencies of all these frequencies are 10 GHz. The data obtained are shown below:

[0109] LOI / (L / min) Dielectric constant (F / m) Dielectric loss Example 1 25.3 2.9 0.0032 Example 2 25.1 3.0 0.0034 Example 3 24.9 3.1 0.0036 Example 4 20.5 Example 5 23.5 Example 6 26.7

[0110] Conclusions: The reaction amounts in Examples 1, 2, and 3 were similar, with adjustments only made to the reaction conditions. Data shows that Example 1 had a relatively high LOI value, indicating that the copper-clad laminate material prepared by this invention has good flame-retardant properties. The copper-clad laminate exhibited low dielectric constant and dielectric loss when tested using the parallel plate capacitance method, indicating that the copper-clad laminate material prepared by this invention has good dielectric properties. Example 4 removed the branched polymer, the main reactant in the filler preparation, and used only modified Al2O3 as the main component of the filler. Compared to Example 1, the flame-retardant effect was poor, not as good as the synergistic effect produced by the three flame-retardant elements Al, P, and N. Example 5 reduced the filler amount by half based on Example 1, and the experimental data showed a decrease in LOI values. Example 6 increased the filler amount by half based on Example 1, and the experimental data showed an improvement in LOI value and flame-retardant properties of the copper-clad laminate.

[0111] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended 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 make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a low-dielectric copper-clad laminate reinforced with alumina filler, characterized in that: Includes the following steps: Step 1: Mix filler, resin, solvent, silane coupling agent, surfactant, curing agent, and accelerator under high-speed stirring to obtain resin solution. The stirring speed is 800-1500 rpm. Step 2: Arrange electronic-grade glass fibers in the resin solution and impregnate both sides, bake at 150℃-200℃ for 6-10 minutes, and then cool to obtain a semi-cured sheet; Step 3: Stack the prepreg sheets, and cover both sides of the stacked prepreg sheets with a layer of copper foil to obtain the board material; Step 4: Press the stacked boards, then insulate them to obtain precast panels. Step 5: Cut the precast board to obtain a low-dielectric copper clad laminate reinforced with alumina filler; The preparation steps of the filler are as follows: S1: Preparation of branched polymer: Under a nitrogen atmosphere, hexachlorocyclotriphosphazene and 4,4'-diaminodiphenylmethane were added to anhydrous toluene. After the solid was completely dissolved, triethylamine was added. The mixture was stirred at 70-80℃ for 10-12 h. After the reaction was completed, the mixture was cooled to room temperature. The reactants were then washed with ethanol and dried under vacuum at 45-55℃ for 8-10 h to obtain the branched polymer. S2: Preparation of modified Al2O3: A mixture of spherical Al2O3 and aqueous ethanol solution was ultrasonically dispersed for 15-25 min to prepare dispersion A. Then, a mixture of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and aqueous ethanol solution was ultrasonically dispersed for 15-25 min to prepare dispersion B. Dispersion B was added dropwise to dispersion A and kept at 70-80℃ for 12-14 h. After the reaction was completed, the mixture was cooled to room temperature to obtain modified Al2O3. S3: Preparation of filler: N,N-dimethylformamide solution, triethylamine, branched polymer prepared in S1 and modified Al2O3 prepared in S2 are mixed and heated to 130-150℃ under nitrogen protection for 6-8 hours. After the reaction is completed, the mixture is washed with anhydrous ethanol and dried.

2. The method for preparing an alumina-filled reinforced low-dielectric copper clad laminate according to claim 1, characterized in that: In step one, the resin is a cyanate ester resin and a bisphenol A type epoxy resin, the solvent is acetone and toluene, the surfactant is a fluorocarbon surfactant, the curing agent is a phenolic resin, and the accelerator is dimethylimidazole.

3. The method for preparing an alumina-filled reinforced low-dielectric copper clad laminate according to claim 2, characterized in that: In step one, by weight, there are 40-60 parts filler, 60-80 parts cyanate ester resin, 40-50 parts bisphenol A epoxy resin, 10-40 parts solvent, 0.5-3.0 parts silane coupling agent, 0.05-0.1 parts surfactant, 3-9 parts curing agent, and 0.05-0.50 parts accelerator.

4. The method for preparing an alumina-filled reinforced low-dielectric copper clad laminate according to claim 1, characterized in that: In step two, the adhesive content of the prepared semi-cured sheet is 50wt%-70wt%.

5. The method for preparing an alumina-filled reinforced low-dielectric copper-clad laminate according to claim 1, characterized in that: In step four, the pressing temperature is 150℃-220℃, and the pressing pressure per unit area is 1Mpa-3Mpa.

6. The method for preparing an alumina-filled reinforced low-dielectric copper clad laminate according to claim 1, characterized in that: In step four, the heat preservation temperature is 180℃-220℃, the heat preservation time is 60min-90min, and the unit area pressure during the heat preservation stage is 2Mpa-4Mpa.

7. An alumina-filled reinforced low-dielectric copper-clad laminate is prepared by the method for preparing an alumina-filled reinforced low-dielectric copper-clad laminate according to any one of claims 1-6.