Halogen-free flame-retardant copper-clad plate substrate material and preparation method thereof

Abstract

The invention discloses a halogen-free flame-retardant copper-clad plate substrate material and a preparation method thereof, and relates to the technical field of copper-clad plates. The halogen-free flame-retardant copper-clad plate substrate material prepared by the invention is prepared by hot-pressing a copper foil on an insulating substrate by using a self-made adhesive; the self-made adhesive comprises an epoxy resin composition, dicyandiamide serving as a curing agent and 2-methylimidazole serving as an accelerant; the insulating substrate comprises bisphenol A epoxy resin, a phenolic resin curing agent, aluminum hydroxide, an accelerant 2-methylimidazole and glass fiber cloth; the self-made adhesive with higher crosslinking density enhances the viscosity and enhances the overall mechanical strength of the material, and the phenolic resin curing agent with flame retardant property is introduced into the insulating substrate to form stronger intramolecular and intermolecular hydrogen bonds, thereby further enhancing the heat resistance and flame retardancy and enhancing the heat resistance and flame retardancy of the insulating substrate. And the bonding strength of the insulating substrate and the copper foil can be improved, and the stripping resistance is improved.

Description

Technical Field

[0001] This invention relates to the field of copper clad laminate technology, specifically to a halogen-free flame-retardant copper clad laminate substrate material and its preparation method. Background Technology

[0002] Copper clad laminate (CCL) is a fundamental material for electronic products. It is made by impregnating reinforcing materials with resin, covering them with copper foil, and then hot-pressing them together. Research on flame retardancy of CCL, which is indispensable for electronic products, is also crucial. Flame retardant modification of CCL usually involves adding flame-retardant halogens to the resin matrix. However, halogen-containing compounds can easily cause environmental pollution and harm people's health when used as flame retardants. Therefore, developing a halogen-free CCL substrate material is a hot research topic.

[0003] Epoxy resin is widely used in the packaging materials of electronic appliances such as semiconductors, integrated circuits, and copper-clad laminates. The limiting oxygen index of ordinary epoxy resin is only about 19.5, which is a flammable substance. Therefore, the copper-clad laminate substrate material prepared from it has potential hazards. How to improve the flame retardancy of epoxy resin has become a key concern. Therefore, this invention studies and prepares a halogen-free flame-retardant copper-clad laminate substrate material with excellent heat resistance and flame retardancy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a halogen-free flame-retardant copper clad laminate substrate material with excellent heat resistance and flame retardancy and its preparation method.

[0005] To address the aforementioned technical problems, the present invention proposes a technical solution: a halogen-free flame-retardant copper-clad laminate substrate material, which is prepared by hot-pressing copper foil onto an insulating substrate using a self-made adhesive; the self-made adhesive comprises an epoxy resin composition, a curing agent dicyandiamide, and an accelerator 2-methylimidazole; the insulating substrate comprises bisphenol A epoxy resin, a phenolic resin curing agent, aluminum hydroxide, an accelerator 2-methylimidazole, and glass fiber cloth.

[0006] Preferably, the epoxy resin composition includes naphthyl epoxy resin, phenyl epoxy resin, and crosslinked furan epoxy resin.

[0007] Preferably, the naphthyl epoxy resin is prepared by reacting di-terminated aminonaphthalene with epoxy resin; the phenyl epoxy resin is prepared by reacting N-(4-anilinophenyl)maleimide with epoxy resin; the crosslinked furan epoxy resin is prepared by reacting N,N-bis(dithiocarboxyl)ethylenediamine with furan epoxy resin; and the di-terminated aminonaphthalene is prepared by reacting 2,7-dihydroxynaphthalene with p-nitrochlorobenzene followed by amination.

[0008] Preferably, the phenolic resin curing agent is prepared by reacting melamine, poly(p-methoxyphenol) carbamate, and aldehyde ethoxyaniline; the poly(p-methoxyphenol) carbamate is prepared by reacting bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol), and isocyanate; and the aldehyde ethoxyaniline is prepared by reacting 3-methyl-N,N-dihydroxyethylaniline with acrylonitrile and then aldehyde-modifying it with N,N-dimethylformamide.

[0009] Preferably, the preparation method of the halogen-free flame-retardant copper-clad laminate substrate material includes the following specific steps: S1. Heat the bisphenol A epoxy resin to 50~60℃ and preheat for 20~40min. Add 0.18~0.22 times the mass of the bisphenol A epoxy resin with di-terminated aminonaphthalene. Stir at 400~800rpm for 10~20min. Heat to 75~85℃ and keep warm for 2~3h. Then continue to heat to 145~155℃ and react for 3~4h. Cool to room temperature to obtain naphthyl epoxy resin. S2. Under a nitrogen atmosphere, N-(4-anilinophenyl)maleimide, bisphenol A epoxy resin and N-methylpyrrolidone are mixed in a mass ratio of 1:1 to 2:3. The mixture is heated to 120 to 140°C, stirred and dissolved, and kept at this temperature for 1 to 2 hours. The temperature is then raised to 145 to 155°C and kept at this temperature for 2 to 3 hours. The temperature is then raised to 175 to 185°C and kept at this temperature for 2 to 3 hours. The temperature is then raised to 195 to 205°C and kept at this temperature for 2 to 3 hours. The mixture is then cooled to room temperature to obtain phenyl epoxy resin. S3. Under a nitrogen atmosphere, N,N-bis(dithiocarboxy)ethylenediamine, furan epoxy resin, N-methylpyrrolidone and accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed in a mass ratio of 1:1~2:3:0.02. After stirring and dissolving, the mixture was transferred to a vacuum drying oven and degassed under vacuum at 30~40℃ for 20~40 min. The temperature was then raised to 75~85℃ and held for 2~3 h. The temperature was then raised to 115~125℃ and reacted for 2~3 h. The temperature was then raised to 145~155℃ and reacted for 4~5 h. The mixture was then cooled to room temperature to obtain crosslinked furan epoxy resin. S4. Mix naphthyl epoxy resin, phenyl epoxy resin and crosslinked furan epoxy resin in a mass ratio of 1:1:1~5, heat to 145~155℃, stir evenly to obtain an epoxy resin composition. Mix the epoxy resin composition and curing agent dicyandiamide, heat to 145~155℃, react for 30~40 min, add accelerator 2-methylimidazole and solvent butanone, stir evenly to obtain a self-made adhesive. S5. A mixture of poly(p-methoxyphenol) urethane, aldehyde ethoxyaniline, oxalic acid (1.8-2.2% by mass) and deionized water in a mass ratio of 100:7-10:10-20:100 is prepared. The mixture is heated to 100-105°C and reacted for 1-2 hours. After cooling to room temperature, the pH is adjusted to 6-7 with triethylamine. Then, 0.3-0.6 times the mass of aldehyde ethoxyaniline and 0.1-0.3 times the mass of melamine are added to the mixture. The mixture is heated to 100-105°C and reacted for 3-4 hours. After vacuum dehydration, a phenolic resin curing agent is obtained. S6. Bisphenol A epoxy resin, phenolic resin curing agent, aluminum hydroxide and accelerator 2-methylimidazole are mixed in a mass ratio of 100:2~3:1:0.2~0.3, heated to 40~60℃, stirred at 1000~2000rpm for 6~10h, degassed and filtered to obtain resin solution. Glass fiber cloth is impregnated in 0.6 times its mass of resin solution for 6~8h, then transferred to drying channel and heated at 150~250℃ for 2~4min to obtain insulating substrate. S7. Coat the surface of the insulating substrate with a self-made adhesive, the mass ratio of the insulating substrate to the self-made adhesive being 30~40:1. Lay copper foil together and cure at 170~180℃ and 10~30MPa for 60~90 minutes. After cooling, cut to obtain a halogen-free flame-retardant copper-clad laminate substrate material with a thickness of 0.8~2.2mm.

[0010] Preferably, in step S1 above, the preparation method of the di-terminated aminonaphthalene is as follows: 2,7-dihydroxynaphthalene, p-nitrochlorobenzene, anhydrous potassium carbonate, toluene, and N,N-dimethylformamide are mixed in a mass ratio of 8:15~16:13~14:15:150, heated to 135~145℃, reacted for 8~9 hours, then heated to 150~152℃, reacted for 1~2 hours, filtered while hot, and allowed to stand for 8~10 hours. The precipitate is then filtered... Then, ferric chloride, activated carbon, and ethylene glycol methyl ether are added. The mass ratio of 2,7-dihydroxynaphthalene, ferric chloride, activated carbon, and ethylene glycol methyl ether is 8:3:10~20:150. The mixture is transferred to a nitrogen atmosphere, heated to 100~110℃, and reacted for 6~8 hours. The mixture is filtered while hot and rotary evaporated. The precipitate is obtained by precipitating with deionized water, washing with anhydrous ethanol and deionized water 3~5 times in sequence, and drying in an oven at 60~70℃ to obtain diaminonaphthalene.

[0011] Preferably, in step S3 above, the preparation method of furan epoxy resin is as follows: furfuryl alcohol resin and bisphenol A epoxy resin are mixed at a mass ratio of 3~6:1, heated to 130~150℃, and reacted for 4~6 hours to obtain furan epoxy resin.

[0012] Preferably, in step S4 above, the mass ratio of the epoxy resin composition to the curing agent dicyandiamide, the accelerator 2-methylimidazole, and the solvent methyl ethyl ketone is 100:1:0.2:200.

[0013] Preferably, in step S5 above, the preparation method of aldehyde ethoxyaniline is as follows: 3-methyl-N,N-dihydroxyethylaniline, hydroquinone, and a sodium methoxide solution with a mass fraction of 22-30% are mixed at a mass ratio of 200:4-6:25. After stirring evenly, acrylonitrile (8-10 times the mass of hydroquinone) is added dropwise at a rate of 1-3 ml / min. The temperature is adjusted to 10-20°C, and the reaction is maintained at this temperature for 40-60 min. Then, acrylonitrile (8-10 times the mass of hydroquinone) is added dropwise again at a rate of 1-3 ml / min. The temperature is lowered to 6-8°C, and the reaction continues for 1.5-2.5 h. Finally, acrylonitrile (8-10 times the mass of hydroquinone) is added dropwise again at a rate of 1-3 ml / min, and the temperature is lowered to 2-4°C. Continue the reaction for 3-4 hours, adjust the pH to 5-6 with hydrochloric acid, add 50-100 times the mass of hydroquinone in hot water at 60-70°C, stir evenly, raise the temperature to room temperature, stir at 200-400 rpm for 1-2 hours, filter, add 21-23 times the mass of hydroquinone in N,N-dimethylformamide, cool to 8-12°C, add 30-40 times the mass of hydroquinone in phosphorus oxychloride, raise the temperature to 85-90°C, keep the reaction at this temperature for 6-8 hours, cool to room temperature, add 50-100 times the mass of hydroquinone in water, hydrolyze for 60-80 minutes, let stand and separate into layers, and obtain aldehyde ethoxyaniline.

[0014] Preferably, in step S5 above, the preparation method of poly(p-methoxyphenol) carbamate is as follows: under a nitrogen atmosphere, bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol) and N,N-dimethylformamide are mixed in a mass ratio of 26~28:30:500~600, heated to 80~90°C, stirred and dissolved, then cooled to 60~70°C, and 0.02~0.04 times the mass of poly(p-methoxyphenol) catalyst dibutyltin dilaurate is added. The mixture is kept at this temperature and 3.2~3.4 times the mass of poly(p-methoxyphenol) diphenylmethane diisocyanate is added. The mixture is heated to 75~85°C and reacted for 4~8 hours to obtain poly(p-methoxyphenol) carbamate.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: The halogen-free flame-retardant copper-clad laminate substrate material prepared by the present invention is obtained by hot pressing copper foil onto an insulating substrate using a self-made adhesive; the self-made adhesive includes an epoxy resin composition, a curing agent dicyandiamide, and an accelerator 2-methylimidazole; the insulating substrate includes bisphenol A epoxy resin, a phenolic resin curing agent, aluminum hydroxide, an accelerator 2-methylimidazole, and glass fiber cloth. The epoxy resin composition includes naphthyl epoxy resin, phenyl epoxy resin, and crosslinked furan epoxy resin. The naphthyl epoxy resin is prepared by reacting di-terminated aminonaphthalene with epoxy resin. The phenyl epoxy resin is prepared by reacting N-(4-anilinophenyl)maleimide with epoxy resin. The crosslinked furan epoxy resin is prepared by reacting N,N-bis(dithiocarboxyl)ethylenediamine with furan epoxy resin. The di-terminated aminonaphthalene is prepared by reacting 2,7-dihydroxynaphthalene with p-nitrochlorobenzene and then amination. This composition enhances the heat resistance and flame retardancy of the material. The ternary epoxy composition not only increases the crosslinking density of the self-made adhesive, thus enhancing its adhesion, but also improves the overall mechanical strength of the material.

[0016] The phenolic resin curing agent is prepared by reacting melamine, poly(p-methoxyphenol) carbamate, and aldehyde ethoxyaniline. Poly(p-methoxyphenol) carbamate is prepared by reacting bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol), and isocyanate. Aldehyde ethoxyaniline is prepared by reacting 3-methyl-N,N-dihydroxyethylaniline with acrylonitrile and then aldehyde-modifying it with N,N-dimethylformamide. The introduction of the flame-retardant phenolic resin curing agent into the insulating substrate forms strong intramolecular and intermolecular hydrogen bonds, which further enhances the heat resistance and flame retardancy. At the same time, it can also improve the bonding strength between the insulating substrate and the copper foil and improve the peel resistance. Detailed Implementation

[0017] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those skilled in the art.

[0018] The bisphenol A epoxy resin in this invention has an epoxy value of 0.41~0.47 mol / 100g.

[0019] To more clearly illustrate the method provided by the present invention, the following embodiments are provided for detailed explanation. The test methods for various indicators of the halogen-free flame-retardant copper-clad laminate substrate materials prepared in the embodiments and comparative examples are as follows: Mechanical properties: The halogen-free flame-retardant copper-clad laminate substrate materials prepared in the examples and comparative examples were subjected to bending strength tests in accordance with GB / T4722.

[0020] Flame retardancy: The oxygen index of the halogen-free flame retardant copper clad laminate substrate materials prepared in the examples and comparative examples was determined in accordance with GB / T2406.

[0021] Heat resistance: The glass transition temperature of the halogen-free flame-retardant copper-clad laminate substrate materials prepared in the examples and comparative examples was tested using a thermal analyzer under a nitrogen atmosphere at a heating rate of 20°C / min. The decomposition temperature was also tested.

[0022] Peel strength: The resistivity of the halogen-free flame-retardant copper-clad laminate substrate materials prepared in the examples and comparative examples was tested in accordance with GB / T4722.

[0023] Example 1 The preparation method of the halogen-free flame-retardant copper-clad laminate substrate material in this embodiment is as follows: S1. Mix 2,7-dihydroxynaphthalene, p-nitrochlorobenzene, anhydrous potassium carbonate, toluene, and N,N-dimethylformamide in a mass ratio of 8:15:13:15:150, heat to 135°C, react for 8 hours, then heat to 150°C and react for 1 hour. Filter while hot and let stand for 8 hours. Add ferric chloride, activated carbon, and ethylene glycol methyl ether to the filtered precipitate. The mass ratio of 2,7-dihydroxynaphthalene, ferric chloride, activated carbon, and ethylene glycol methyl ether is 8:3:10:150. Transfer to a nitrogen atmosphere and heat... The mixture was heated to 100℃ and reacted for 6 hours. It was then filtered and rotary evaporated while hot. The precipitate was obtained by precipitating with deionized water and washed three times with anhydrous ethanol and deionized water. The precipitate was then dried in an oven at 60℃ to obtain diaminonaphthalene. Bisphenol A epoxy resin was heated to 50℃ and preheated for 20 minutes. Diaminonaphthalene was added at 0.18 times the mass of bisphenol A epoxy resin and stirred at 400 rpm for 10 minutes. The temperature was then raised to 75℃ and kept at that temperature for 2 hours. The temperature was then raised to 145℃ and reacted for 3 hours. The mixture was then cooled to room temperature to obtain naphthyl epoxy resin. S2. Under a nitrogen atmosphere, N-(4-anilinophenyl)maleimide, bisphenol A epoxy resin and N-methylpyrrolidone were mixed in a mass ratio of 1:1:3. The mixture was heated to 120°C, stirred and dissolved, and kept at this temperature for 1 hour. The temperature was then raised to 145°C and kept at this temperature for 2 hours. The temperature was then raised to 175°C and kept at this temperature for 2 hours. The temperature was then raised to 195°C and kept at this temperature for 2 hours. The mixture was then cooled to room temperature to obtain phenyl epoxy resin. S3. Furfuryl alcohol resin and bisphenol A epoxy resin were mixed at a mass ratio of 3:1, heated to 130℃, and reacted for 4 hours to obtain furan epoxy resin; under a nitrogen atmosphere, N,N-bis(dithiocarboxy)ethylenediamine, furan epoxy resin, N-methylpyrrolidone and accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed at a mass ratio of 1:1:3:0.02, stirred and dissolved, transferred to a vacuum drying oven, degassed under vacuum at 30℃ for 20 minutes, heated to 75℃, kept at that temperature for 2 hours, then heated to 115℃ and reacted for 2 hours, then heated to 145℃ and reacted for 4 hours, and finally cooled to room temperature to obtain crosslinked furan epoxy resin; S4. Naphthyl epoxy resin, phenyl epoxy resin and crosslinked furan epoxy resin are mixed in a mass ratio of 1:1:1, heated to 145℃, and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition and curing agent dicyandiamide are mixed, heated to 145℃, reacted for 30 min, and then accelerator 2-methylimidazole and solvent methyl ethyl ketone are added. The mass ratio of epoxy resin composition to curing agent dicyandiamide, accelerator 2-methylimidazole and solvent methyl ethyl ketone is 100:1:0.2:200. The mixture is stirred evenly to obtain a self-made adhesive. S5. Mix 3-methyl-N,N-dihydroxyethylaniline, hydroquinone, and a 22% sodium methoxide solution at a mass ratio of 200:4:25. After stirring until homogeneous, add acrylonitrile at a rate of 1 ml / min, which is 8 times the mass of hydroquinone. Adjust the temperature to 10°C and maintain the reaction for 40 min. Add acrylonitrile at a rate of 1 ml / min again, cool the temperature to 6°C, and continue the reaction for 1.5 h. Add acrylonitrile at a rate of 1 ml / min again, cool the temperature to 2°C, and continue the reaction for 3 h. Adjust the pH with hydrochloric acid. Add 50 times the mass of hydroquinone to 60°C hot water, stir well, then heat to room temperature and stir at 200 rpm for 1 hour. Filter, then add 21 times the mass of hydroquinone to N,N-dimethylformamide, cool to 8°C, add 30 times the mass of hydroquinone to phosphorus oxychloride, heat to 85°C, maintain the temperature for 6 hours, cool to room temperature, add 50 times the mass of hydroquinone to water, hydrolyze for 60 minutes, allow to stand and separate into layers, and obtain aldehyde ethoxyaniline; under a nitrogen atmosphere, bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol), and N, N-Dimethylformamide was mixed at a mass ratio of 26:30:500, heated to 80°C, stirred until dissolved, and then cooled to 60°C. Dibutyltin dilaurate catalyst (0.02 times the mass of poly(p-methoxyphenol)) was added, and the mixture was kept at this temperature. Diphenylmethane diisocyanate (3.2 times the mass of poly(p-methoxyphenol)) was then added, and the mixture was heated to 75°C and reacted for 4 hours to obtain poly(p-methoxyphenol) carbamate. Poly(p-methoxyphenol) carbamate and aldehyde ethoxybenzene were then... Amine, oxalic acid (1.8% by mass), and deionized water were mixed in a mass ratio of 100:7:10:100. The mixture was heated to 100°C and reacted for 1 hour. After cooling to room temperature, the pH was adjusted to 6 with triethylamine. Aldehyde ethoxyaniline (0.3 times the mass of poly(p-methoxyphenol)) and melamine (0.1 times the mass of poly(p-methoxyphenol)) were added. The mixture was heated to 100°C and reacted for 3 hours. After vacuum dehydration, a phenolic resin curing agent was obtained. S6. Bisphenol A epoxy resin, phenolic resin curing agent, aluminum hydroxide, and accelerator 2-methylimidazole are mixed in a mass ratio of 100:2:1:0.2, heated to 40℃, and stirred at 1000 rpm for 6 hours. After degassing and filtration, a resin solution is obtained. Fiberglass cloth is impregnated in 0.6 times its weight of the resin solution for 6 hours, then transferred to a drying channel and heated at 150℃ for 2 minutes to obtain an insulating substrate. S7. Coat the surface of the insulating substrate with a self-made adhesive, the mass ratio of the insulating substrate to the self-made adhesive is 30:1, stack copper foil, and cure by hot pressing at 170℃ and 10MPa for 60 minutes. After cooling, cut to obtain a halogen-free flame-retardant copper-clad laminate substrate material with a thickness of 0.8mm.

[0024] Example 2 The preparation method of the halogen-free flame-retardant copper-clad laminate substrate material in this embodiment is as follows: S1. Mix 2,7-dihydroxynaphthalene, p-nitrochlorobenzene, anhydrous potassium carbonate, toluene, and N,N-dimethylformamide in a mass ratio of 8:15.5:13.5:15:150, heat to 140℃, react for 8.5 h, then heat to 151℃ and react for 1.5 h. Filter while hot and let stand for 9 h. Add ferric chloride, activated carbon, and ethylene glycol methyl ether to the filtered precipitate. The mass ratio of 2,7-dihydroxynaphthalene, ferric chloride, activated carbon, and ethylene glycol methyl ether is 8:3:15:150. Transfer to a nitrogen atmosphere. The temperature was raised to 105℃ and reacted for 7 hours. The mixture was filtered while hot and rotary evaporated. The precipitate was precipitated with deionized water and washed four times with anhydrous ethanol and deionized water. The precipitate was then dried in an oven at 65℃ to obtain diaminonaphthalene. Bisphenol A epoxy resin was heated to 55℃ and preheated for 30 minutes. Diaminonaphthalene was added at 0.20 times its mass of bisphenol A epoxy resin and stirred at 600 rpm for 15 minutes. The temperature was raised to 80℃ and held for 2.5 hours. The temperature was then raised to 150℃ and reacted for 3.5 hours. The mixture was then cooled to room temperature to obtain naphthyl epoxy resin. S2. Under a nitrogen atmosphere, N-(4-anilinophenyl)maleimide, bisphenol A epoxy resin and N-methylpyrrolidone were mixed in a mass ratio of 1:1.5:3. The mixture was heated to 130°C, stirred and dissolved, and kept at this temperature for 1.5 h. The temperature was then raised to 150°C and kept at this temperature for 2.5 h. The temperature was then raised to 180°C and kept at this temperature for 2.5 h. The temperature was then raised to 200°C and kept at this temperature for 2.5 h. The mixture was then cooled to room temperature to obtain phenyl epoxy resin. S3. Furfuryl alcohol resin and bisphenol A epoxy resin were mixed at a mass ratio of 4.5:1, heated to 140℃, and reacted for 5 hours to obtain furan epoxy resin; under a nitrogen atmosphere, N,N-bis(dithiocarboxy)ethylenediamine, furan epoxy resin, N-methylpyrrolidone, and accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed at a mass ratio of 1:1.5:3:0.02, stirred and dissolved, transferred to a vacuum drying oven, degassed under vacuum at 35℃ for 30 minutes, heated to 80℃, held for 2.5 hours, then heated to 120℃ and reacted for 2.5 hours, then heated to 150℃ and reacted for 4.5 hours, and finally cooled to room temperature to obtain crosslinked furan epoxy resin; S4. Naphthyl epoxy resin, phenyl epoxy resin and crosslinked furan epoxy resin are mixed in a mass ratio of 1:1:3, heated to 150℃, and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition and curing agent dicyandiamide are mixed, heated to 150℃, reacted for 35 min, and then accelerator 2-methylimidazole and solvent methyl ethyl ketone are added. The mass ratio of epoxy resin composition to curing agent dicyandiamide, accelerator 2-methylimidazole and solvent methyl ethyl ketone is 100:1:0.2:200. The mixture is stirred evenly to obtain a self-made adhesive. S5. Mix 3-methyl-N,N-dihydroxyethylaniline, hydroquinone, and a 26% sodium methoxide solution at a mass ratio of 200:5:25. After stirring thoroughly, add acrylonitrile (9 times the mass of hydroquinone) dropwise at a rate of 2 ml / min. Adjust the temperature to 15°C and maintain the reaction for 50 min. Add acrylonitrile (9 times the mass of hydroquinone) dropwise again at a rate of 2 ml / min. Cool the temperature to 7°C and continue the reaction for 2 h. Add acrylonitrile (9 times the mass of hydroquinone) dropwise again at a rate of 2 ml / min. Cool the temperature to 3°C and continue the reaction for 3.5 h. Adjust the pH to 5.5 with hydrochloric acid. Add 80 times the mass of hydroquinone to 65°C hot water, stir until homogeneous, then heat to room temperature and stir at 200-400 rpm for 1.5 hours. Filter, then add 22 times the mass of hydroquinone to N,N-dimethylformamide, cool to 8-12°C, add 35 times the mass of hydroquinone to phosphorus oxychloride, heat to 88°C, maintain the temperature for 6-8 hours, cool to room temperature, add 80 times the mass of hydroquinone to water, hydrolyze for 70 minutes, allow to stand and separate into layers, and obtain aldehyde ethoxyaniline; under a nitrogen atmosphere, bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol), and N, N-Dimethylformamide was mixed at a mass ratio of 27:30:550, heated to 85°C, stirred until dissolved, and then cooled to 65°C. Dibutyltin dilaurate catalyst (0.03 times the mass of poly(p-methoxyphenol)) was added, and the mixture was kept at this temperature. Diphenylmethane diisocyanate (3.3 times the mass of poly(p-methoxyphenol)) was then added, and the mixture was heated to 80°C and reacted for 6 hours to obtain poly(p-methoxyphenol) carbamate. Poly(p-methoxyphenol) carbamate, aldehyde ethoxyaniline, and other components were then added. Oxalic acid with a mass fraction of 2% and deionized water were mixed in a mass ratio of 100:8.5:15:100, heated to 103℃, reacted for 1.5 h, cooled to room temperature, and the pH was adjusted to 6.5 with triethylamine. Aldehyde ethoxyaniline (0.5 times the mass of poly(p-methoxyphenol)) and melamine (0.2 times the mass of poly(p-methoxyphenol)) were added, heated to 103℃, reacted for 3.5 h, and dehydrated under vacuum to obtain a phenolic resin curing agent. S6. Bisphenol A epoxy resin, phenolic resin curing agent, aluminum hydroxide, and accelerator 2-methylimidazole are mixed in a mass ratio of 100:2.5:1:0.25. The mixture is heated to 50°C and stirred at 1500 rpm for 8 hours. After degassing and filtration, a resin solution is obtained. Fiberglass cloth is impregnated in 0.6 times its weight of the resin solution for 7 hours. After impregnation, the mixture is transferred to a drying channel and heated at 200°C for 3 minutes to obtain an insulating substrate. S7. Coat the surface of the insulating substrate with a self-made adhesive, the mass ratio of the insulating substrate to the self-made adhesive is 35:1, stack copper foil, and cure by hot pressing at 175℃ and 20MPa for 80 minutes. After cooling, cut to obtain a halogen-free flame-retardant copper-clad laminate substrate material with a thickness of 1.6mm.

[0025] Example 3 The preparation method of the halogen-free flame-retardant copper-clad laminate substrate material in this embodiment is as follows: S1. Mix 2,7-dihydroxynaphthalene, p-nitrochlorobenzene, anhydrous potassium carbonate, toluene, and N,N-dimethylformamide in a mass ratio of 8:16:14:15:150, heat to 145℃, react for 9 hours, then heat to 152℃ and react for 2 hours. Filter while hot and let stand for 10 hours. Add ferric chloride, activated carbon, and ethylene glycol methyl ether to the filtered precipitate. The mass ratio of 2,7-dihydroxynaphthalene, ferric chloride, activated carbon, and ethylene glycol methyl ether is 8:3:20:150. Transfer to a nitrogen atmosphere and heat... The mixture was heated to 110℃ and reacted for 8 hours. It was then filtered and rotary evaporated while hot. The precipitate was obtained by precipitating with deionized water and washed five times with anhydrous ethanol and deionized water. It was then dried in an oven at 70℃ to obtain diaminonaphthalene. Bisphenol A epoxy resin was heated to 60℃ and preheated for 40 minutes. Diaminonaphthalene was added at 0.22 times the mass of bisphenol A epoxy resin. The mixture was stirred at 800 rpm for 20 minutes. The temperature was then raised to 85℃ and kept at that temperature for 3 hours. The temperature was then raised to 155℃ and reacted for 4 hours. The mixture was then cooled to room temperature to obtain naphthyl epoxy resin. S2. Under a nitrogen atmosphere, N-(4-anilinophenyl)maleimide, bisphenol A epoxy resin and N-methylpyrrolidone were mixed in a mass ratio of 1:2:3. The mixture was heated to 140°C, stirred and dissolved, and kept at this temperature for 2 hours. The temperature was then raised to 155°C and kept at this temperature for 3 hours. The temperature was then raised to 185°C and kept at this temperature for 3 hours. The temperature was then raised to 205°C and kept at this temperature for 3 hours. The mixture was then cooled to room temperature to obtain phenyl epoxy resin. S3. Furfuryl alcohol resin and bisphenol A epoxy resin were mixed at a mass ratio of 6:1, heated to 150℃, and reacted for 6 hours to obtain furan epoxy resin; under a nitrogen atmosphere, N,N-bis(dithiocarboxy)ethylenediamine, furan epoxy resin, N-methylpyrrolidone and accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed at a mass ratio of 1:2:3:0.02, stirred and dissolved, transferred to a vacuum drying oven, degassed under vacuum at 40℃ for 40 minutes, heated to 85℃, kept at that temperature for 3 hours, then heated to 125℃ and reacted for 3 hours, then heated to 155℃ and reacted for 5 hours, and finally cooled to room temperature to obtain crosslinked furan epoxy resin; S4. Naphthyl epoxy resin, phenyl epoxy resin and crosslinked furan epoxy resin are mixed in a mass ratio of 1:1:5, heated to 155℃, and stirred evenly to obtain an epoxy resin composition. The epoxy resin composition and curing agent dicyandiamide are mixed, heated to 155℃, reacted for 40 min, and then accelerator 2-methylimidazole and solvent methyl ethyl ketone are added. The mass ratio of epoxy resin composition to curing agent dicyandiamide, accelerator 2-methylimidazole and solvent methyl ethyl ketone is 100:1:0.2:200. The mixture is stirred evenly to obtain a self-made adhesive. S5. Mix 3-methyl-N,N-dihydroxyethylaniline, hydroquinone, and 30% sodium methoxide solution at a mass ratio of 200:6:25. After stirring until homogeneous, add 10 times the mass of hydroquinone (acrylonitrile) dropwise at a rate of 3 ml / min. Adjust the temperature to 20°C and maintain the reaction temperature for 60 min. Add 10 times the mass of hydroquinone (acrylonitrile) dropwise again at a rate of 3 ml / min. Cool the temperature to 8°C and continue the reaction for 2.5 h. Add 10 times the mass of hydroquinone (acrylonitrile) dropwise again at a rate of 3 ml / min. Cool the temperature to 4°C and continue the reaction for 4 h. Adjust the pH with hydrochloric acid. Add 100 times the mass of hydroquinone in 70°C hot water, stir until homogeneous, then heat to room temperature and stir at 400 rpm for 2 hours. Filter, then add 23 times the mass of hydroquinone in N,N-dimethylformamide, cool to 12°C, add 40 times the mass of hydroquinone in phosphorus oxychloride, heat to 90°C, maintain the temperature for 8 hours, cool to room temperature, add 100 times the mass of hydroquinone in water, hydrolyze for 80 minutes, allow to stand and separate into layers, and obtain aldehyde ethoxyaniline; under a nitrogen atmosphere, bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol), and N, N-Dimethylformamide was mixed at a mass ratio of 28:30:600, heated to 90°C, stirred until dissolved, and then cooled to 70°C. Dibutyltin dilaurate catalyst (0.04 times the mass of poly(p-methoxyphenol)) was added, and the mixture was kept at this temperature. Diphenylmethane diisocyanate (3.4 times the mass of poly(p-methoxyphenol)) was then added, and the mixture was heated to 85°C and reacted for 8 hours to obtain poly(p-methoxyphenol) urethane. Poly(p-methoxyphenol) urethane and aldehyde ethoxybenzene were then... Amine, oxalic acid (2.2% by mass), and deionized water were mixed in a mass ratio of 100:10:20:100. The mixture was heated to 105°C and reacted for 2 hours. After cooling to room temperature, the pH was adjusted to 7 with triethylamine. Aldehyde ethoxyaniline (0.6 times the mass of poly(p-methoxyphenol)) and melamine (0.3 times the mass of poly(p-methoxyphenol)) were added. The mixture was heated to 105°C and reacted for 4 hours. After vacuum dehydration, a phenolic resin curing agent was obtained. S6. Bisphenol A epoxy resin, phenolic resin curing agent, aluminum hydroxide, and accelerator 2-methylimidazole are mixed in a mass ratio of 100:3:1:0.3, heated to 60℃, and stirred at 2000 rpm for 10 hours. After degassing and filtration, a resin solution is obtained. Fiberglass cloth is impregnated in 0.6 times its weight of the resin solution for 8 hours, then transferred to a drying channel and heated at 250℃ for 4 minutes to obtain an insulating substrate. S7. Coat the surface of the insulating substrate with a self-made adhesive, the mass ratio of the insulating substrate to the self-made adhesive is 40:1, stack copper foil, and cure by hot pressing at 180℃ and 30MPa for 90min. After cooling, cut to obtain a halogen-free flame-retardant copper-clad laminate substrate material with a thickness of 2.2mm.

[0026] Comparative Example 1 The preparation method of Comparative Example 1 is the same as that of Example 2. The difference between this halogen-free flame-retardant copper-clad laminate substrate material and that of Example 2 is that the epoxy resin composition only includes naphthyl epoxy resin and phenyl epoxy resin.

[0027] Comparative Example 2 The preparation method of Comparative Example 2 is the same as that of Example 2. The difference between this halogen-free flame-retardant copper-clad laminate substrate material and that of Example 2 is that the epoxy resin composition includes only phenyl epoxy resin and crosslinked furan epoxy resin.

[0028] Comparative Example 3 The preparation method of Comparative Example 3 is the same as that of Example 2. The difference between this halogen-free flame-retardant copper-clad laminate substrate material and that of Example 2 is that the epoxy resin composition includes only naphthyl epoxy resin and crosslinked furan epoxy resin.

[0029] Comparative Example 4 The preparation method of Comparative Example 4 is the same as that of Example 2. The difference between this halogen-free flame-retardant copper-clad laminate substrate material and Example 2 is that the phenolic resin curing agent is prepared by reacting melamine, poly(p-methoxyphenol) carbamate, and formaldehyde.

[0030] Comparative Example 5 The preparation method of Comparative Example 5 is the same as that of Example 2. The difference between this halogen-free flame-retardant copper-clad laminate substrate material and that of Example 2 is that the phenolic resin curing agent is prepared by reacting melamine, phenol and aldehyde ethoxyaniline.

[0031] Comparative Example 6 The preparation method of Comparative Example 6 is the same as that of Example 2. The difference between this halogen-free flame-retardant copper-clad laminate substrate material and that of Example 2 is that the phenolic resin curing agent is prepared by reacting melamine, phenol and formaldehyde.

[0032] Comparative Example 7 The preparation method of Comparative Example 7 is the same as that of Example 2. The difference between this halogen-free flame-retardant copper-clad laminate substrate material and that of Example 2 is that it is prepared by hot pressing copper foil onto an insulating substrate.

[0033] Example of effect Table 1 below presents the performance analysis results of the halogen-free flame-retardant copper-clad laminate substrate materials prepared using Examples 1 to 3 and Comparative Examples 1 to 5 of the present invention: By comparing the experimental data of the examples and comparative examples in Table 1, it can be clearly found that the halogen-free flame-retardant copper-clad laminate substrate materials prepared using Examples 1, 2, and 3 have superior mechanical properties, flame retardancy, heat resistance, and peel strength.

[0034] A comparison of the experimental data from Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 reveals that the di-terminated aminonaphthalene is prepared by reacting 2,7-dihydroxynaphthalene with p-nitrochlorobenzene and then amination, which enhances the heat resistance and flame retardancy of the material. The ternary epoxy composition not only increases the crosslinking density of the self-made adhesive, thus enhancing its adhesion, but also improves the overall mechanical strength of the material.

[0035] A comparison of the experimental data from Examples 1, 2, and 3 and Comparative Examples 4, 5, 6, and 7 reveals that the introduction of a flame-retardant phenolic resin curing agent into the insulating substrate forms strong intramolecular and intermolecular hydrogen bonds, further enhancing heat resistance and flame retardancy. Simultaneously, it also improves the bonding strength between the insulating substrate and the copper foil, and enhances peel resistance.

[0036] Obviously, the above embodiments are merely examples to clearly illustrate the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, these obvious variations or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A halogen-free flame-retardant copper-clad laminate substrate material, characterized in that, It is made by hot pressing copper foil onto an insulating substrate using a homemade adhesive; the homemade adhesive includes an epoxy resin composition, a curing agent dicyandiamide, and an accelerator 2-methylimidazole; the insulating substrate includes bisphenol A epoxy resin, a phenolic resin curing agent, aluminum hydroxide, an accelerator 2-methylimidazole, and glass fiber cloth.

2. The halogen-free flame-retardant copper-clad laminate substrate material according to claim 1, characterized in that, The epoxy resin composition includes naphthyl epoxy resin, phenyl epoxy resin, and crosslinked furan epoxy resin.

3. The halogen-free flame-retardant copper-clad laminate substrate material according to claim 2, characterized in that, The naphthyl epoxy resin is prepared by reacting di-terminated aminonaphthalene with epoxy resin; the phenyl epoxy resin is prepared by reacting N-(4-anilinophenyl)maleimide with epoxy resin; the crosslinked furan epoxy resin is prepared by reacting N,N-bis(dithiocarboxyl)ethylenediamine with furan epoxy resin; and the di-terminated aminonaphthalene is prepared by reacting 2,7-dihydroxynaphthalene with p-nitrochlorobenzene and then amination.

4. The halogen-free flame-retardant copper-clad laminate substrate material according to claim 1, characterized in that, The phenolic resin curing agent is prepared by reacting melamine, poly(p-methoxyphenol) carbamate, and aldehyde ethoxyaniline; the poly(p-methoxyphenol) carbamate is prepared by reacting bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol), and isocyanate; the aldehyde ethoxyaniline is prepared by reacting 3-methyl-N,N-dihydroxyethylaniline with acrylonitrile, followed by aldehyde aldehyde formation with N,N-dimethylformamide.

5. The method for preparing a halogen-free flame-retardant copper-clad laminate substrate material according to claim 1, characterized in that, The specific steps include the following: S1. Heat the bisphenol A epoxy resin to 50~60℃ and preheat for 20~40min. Add 0.18~0.22 times the mass of the bisphenol A epoxy resin with di-terminated aminonaphthalene. Stir at 400~800rpm for 10~20min. Heat to 75~85℃ and keep warm for 2~3h. Then continue to heat to 145~155℃ and react for 3~4h. Cool to room temperature to obtain naphthyl epoxy resin. S2. Under a nitrogen atmosphere, N-(4-anilinophenyl)maleimide, bisphenol A epoxy resin and N-methylpyrrolidone are mixed in a mass ratio of 1:1 to 2:

3. The mixture is heated to 120 to 140°C, stirred and dissolved, and kept at this temperature for 1 to 2 hours. The temperature is then raised to 145 to 155°C and kept at this temperature for 2 to 3 hours. The temperature is then raised to 175 to 185°C and kept at this temperature for 2 to 3 hours. The temperature is then raised to 195 to 205°C and kept at this temperature for 2 to 3 hours. The mixture is then cooled to room temperature to obtain phenyl epoxy resin. S3. Under a nitrogen atmosphere, N,N-bis(dithiocarboxy)ethylenediamine, furan epoxy resin, N-methylpyrrolidone and accelerator 2,4,6-tris(dimethylaminomethyl)phenol were mixed in a mass ratio of 1:1~2:3:0.

02. After stirring and dissolving, the mixture was transferred to a vacuum drying oven and degassed under vacuum at 30~40℃ for 20~40 min. The temperature was then raised to 75~85℃ and held for 2~3 h. The temperature was then raised to 115~125℃ and reacted for 2~3 h. The temperature was then raised to 145~155℃ and reacted for 4~5 h. The mixture was then cooled to room temperature to obtain crosslinked furan epoxy resin. S4. Mix naphthyl epoxy resin, phenyl epoxy resin and crosslinked furan epoxy resin in a mass ratio of 1:1:1~5, heat to 145~155℃, stir evenly to obtain an epoxy resin composition. Mix the epoxy resin composition and curing agent dicyandiamide, heat to 145~155℃, react for 30~40 min, add accelerator 2-methylimidazole and solvent butanone, stir evenly to obtain a self-made adhesive. S5. A mixture of poly(p-methoxyphenol) urethane, aldehyde ethoxyaniline, oxalic acid (1.8-2.2% by mass) and deionized water in a mass ratio of 100:7-10:10-20:100 is prepared. The mixture is heated to 100-105°C and reacted for 1-2 hours. After cooling to room temperature, the pH is adjusted to 6-7 with triethylamine. Then, 0.3-0.6 times the mass of aldehyde ethoxyaniline and 0.1-0.3 times the mass of melamine are added to the mixture. The mixture is heated to 100-105°C and reacted for 3-4 hours. After vacuum dehydration, a phenolic resin curing agent is obtained. S6. Bisphenol A epoxy resin, phenolic resin curing agent, aluminum hydroxide and accelerator 2-methylimidazole are mixed in a mass ratio of 100:2~3:1:0.2~0.3, heated to 40~60℃, stirred at 1000~2000rpm for 6~10h, degassed and filtered to obtain resin solution. Glass fiber cloth is impregnated in 0.6 times its mass of resin solution for 6~8h, then transferred to drying channel and heated at 150~250℃ for 2~4min to obtain insulating substrate. S7. Coat the surface of the insulating substrate with a self-made adhesive, the mass ratio of the insulating substrate to the self-made adhesive being 30~40:

1. Lay copper foil together and cure at 170~180℃ and 10~30MPa for 60~90 minutes. After cooling, cut to obtain a halogen-free flame-retardant copper-clad laminate substrate material with a thickness of 0.8~2.2mm.

6. The method for preparing a halogen-free flame-retardant copper-clad laminate substrate material according to claim 5, characterized in that, In step S1 above, the preparation method of diaminonaphthalene is as follows: 2,7-dihydroxynaphthalene, p-nitrochlorobenzene, anhydrous potassium carbonate, toluene, and N,N-dimethylformamide are mixed in a mass ratio of 8:15~16:13~14:15:150, heated to 135~145℃, reacted for 8~9 hours, then heated to 150~152℃, reacted for 1~2 hours, filtered while hot, and allowed to stand for 8~10 hours. The precipitate obtained by vacuum filtration is then added... Ferric chloride, activated carbon, and ethylene glycol methyl ether were added to the mixture. The mass ratio of 2,7-dihydroxynaphthalene, ferric chloride, activated carbon, and ethylene glycol methyl ether was 8:3:10~20:

150. The mixture was transferred to a nitrogen atmosphere, heated to 100~110℃, and reacted for 6~8 hours. The mixture was filtered while hot and rotary evaporated. The precipitate was obtained by precipitating with deionized water and washed 3~5 times with anhydrous ethanol and deionized water, respectively. The precipitate was then dried in an oven at 60~70℃ to obtain diaminonaphthalene.

7. The method for preparing a halogen-free flame-retardant copper-clad laminate substrate material according to claim 5, characterized in that, In step S3 above, the preparation method of furan epoxy resin is as follows: mix furfuryl alcohol resin and bisphenol A epoxy resin at a mass ratio of 3~6:1, heat to 130~150℃, and react for 4~6 hours to obtain furan epoxy resin.

8. The method for preparing a halogen-free flame-retardant copper-clad laminate substrate material according to claim 5, characterized in that, In step S4 above, the mass ratio of the epoxy resin composition to the curing agent dicyandiamide, the accelerator 2-methylimidazole, and the solvent methyl ethyl ketone is 100:1:0.2:

200.

9. The method for preparing a halogen-free flame-retardant copper-clad laminate substrate material according to claim 5, characterized in that, In step S5 above, the preparation method of aldehyde ethoxyaniline is as follows: 3-methyl-N,N-dihydroxyethylaniline, hydroquinone, and a 22-30% sodium methoxide solution are mixed at a mass ratio of 200:4-6:

25. After stirring evenly, 8-10 times the mass of hydroquinone (by weight) of acrylonitrile are added dropwise at a rate of 1-3 ml / min. The temperature is adjusted to 10-20°C, and the reaction is maintained at this temperature for 40-60 min. Then, 8-10 times the mass of hydroquinone (by weight) of acrylonitrile is added dropwise again at a rate of 1-3 ml / min. The temperature is lowered to 6-8°C, and the reaction continues for 1.5-2.5 h. Finally, 8-10 times the mass of hydroquinone (by weight) of acrylonitrile is added dropwise again at a rate of 1-3 ml / min, and the temperature is lowered to 2-4°C. Continue the reaction for 3-4 hours, adjust the pH to 5-6 with hydrochloric acid, add 50-100 times the mass of hydroquinone in hot water at 60-70°C, stir evenly, raise the temperature to room temperature, stir at 200-400 rpm for 1-2 hours, filter, add 21-23 times the mass of hydroquinone in N,N-dimethylformamide, cool to 8-12°C, add 30-40 times the mass of hydroquinone in phosphorus oxychloride, raise the temperature to 85-90°C, keep the reaction at this temperature for 6-8 hours, cool to room temperature, add 50-100 times the mass of hydroquinone in water, hydrolyze for 60-80 minutes, let stand and separate into layers, and obtain aldehyde ethoxyaniline.

10. The method for preparing a halogen-free flame-retardant copper-clad laminate substrate material according to claim 5, characterized in that, In step S5 above, the preparation method of poly(p-methoxyphenol) urethane is as follows: Under a nitrogen atmosphere, bis(4-hydroxyphenyl)phenylphosphine oxide, poly(p-methoxyphenol) and N,N-dimethylformamide are mixed in a mass ratio of 26~28:30:500~600, heated to 80~90℃, stirred and dissolved, then cooled to 60~70℃, and 0.02~0.04 times the mass of poly(p-methoxyphenol) catalyst dibutyltin dilaurate is added. The mixture is kept at this temperature and 3.2~3.4 times the mass of poly(p-methoxyphenol) diphenylmethane diisocyanate is added. The mixture is heated to 75~85℃ and reacted for 4~8 hours to obtain poly(p-methoxyphenol) urethane urethane.

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