A high heat-resistant copper-clad laminate and its preparation process

Abstract

The present invention provides a high heat-resistant copper-clad laminate and a preparation process thereof, belonging to the technical field of copper-clad laminates; the preparation process thereof comprises the following steps: pretreating a polyimide film; preparing a mixed glue solution; preparing a semi-cured sheet; and hot pressing and curing. The present invention first uses m-diethynylbenzene and methylphenyldichlorosilane as raw materials to react and prepare a silicon-containing resin, and then uses isosorbide bis(terephthalate), bisphenol A and dibenzoate as raw materials to react and prepare a modifier under the catalysis of 4-dimethylaminopyridine. When the modifier is used to modify the silicon-containing resin to prepare a modified silicon-containing resin, the modifier can improve the thermal conductivity of the silicon-containing resin, which is helpful for the uniform distribution of heat and further improves the heat resistance of the silicon-containing resin. Therefore, after the modified silicon-containing resin is added to the modified glue solution, the heat resistance of the modified glue solution can be effectively improved, thereby achieving the effect of improving the heat resistance of the copper-clad laminate.

Description

Technical Field

[0001] The present invention relates to the technical field of copper clad laminates, and in particular to a high-heat-resistant copper clad laminate and a preparation process thereof. Background Art

[0002] Copper clad laminate refers to a copper clad laminate material made of a composite pressing of copper foil, adhesive and insulating film material. After the prepared copper clad laminate is subjected to subsequent welding, etching, punching and other process treatments, it is widely used in printed circuit boards in computers, mobile phones, medical and health equipment, aerospace and navigation and other fields. Copper clad laminates can be divided into rigid copper clad laminates and flexible copper clad laminates according to their mechanical rigidity. The film materials used for rigid copper clad laminates are mostly wood pulp paper, multi-layer glass fiber cloth, etc., while flexible copper clad laminates mostly use flexible films such as polyethylene terephthalate film, polyesterimide film and polyimide film as reinforcement materials. Since flexible copper clad laminates have the characteristics of high wiring density, light weight and good bendability compared to rigid boards, their applications are becoming more and more extensive.

[0003] Although existing polyimide films have advantages such as low thermal shrinkage and good dimensional stability, they have poor adhesion to copper foil and insufficient heat resistance and flame retardancy, and cannot meet the requirements of high welding temperatures.

[0004] Therefore, it is necessary to propose a high-heat-resistant copper clad laminate with good flame retardancy and a preparation process thereof to meet high-temperature welding requirements. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a high heat-resistant copper clad laminate and a preparation process thereof.

[0006] A preparation process for a high heat-resistant copper-clad laminate comprises the following steps:

[0007] S1: Pretreatment of polyimide film

[0008] The thermosetting polyimide film is placed in a 5% sodium hydroxide aqueous solution at 50-60° C., soaked for 3-5 minutes, taken out and dried to obtain a pretreated polyimide film;

[0009] S2: Preparation of mixed glue

[0010] The modified silicone resin liquid, the modified adhesive liquid and the composite flame retardant material are stirred and mixed uniformly to obtain a mixed adhesive liquid;

[0011] S3: Preparing prepreg

[0012] Apply the mixed adhesive solution on the surface of the pretreated polyimide film, and bake at 80-90°C and 130-150°C for 10-12 hours and 1-2 hours, respectively, to obtain a prepreg;

[0013] S4: Hot pressing curing

[0014] Several sheets of the above-mentioned prepregs are stacked together, cut, and then coated with copper foil on one or both sides, and then subjected to hot pressing and curing treatment to obtain a high heat-resistant copper-clad laminate;

[0015] The mixed adhesive solution comprises, by weight, 20-30 parts of a modified silicone resin solution, 45-55 parts of a modified adhesive solution, and 30-40 parts of a composite flame retardant material;

[0016] The raw material components required for the modified silicone resin liquid include, by weight: 10-12 parts of isosorbide bis(terephthalate), 1-2 parts of bisphenol A, 16-20 parts of dibenzoate, 0.01-0.03 parts of 4-dimethylaminopyridine, 30-40 parts of silicone resin, and 55-75 parts of N,N-dimethylformamide;

[0017] The raw material components required for the modified adhesive solution include, by weight, 16-20 parts of 2,4-toluene diisocyanate, 21-23 parts of isophorone diisocyanate, 34-42 parts of bisphenol A dianhydride, 45-50 parts of diphenyl ether dianhydride, 20-30 parts of terminal hydroxyl polydimethylsiloxane and 60-70 parts of N,N′-dimethylacetamide.

[0018] Furthermore, the preparation steps of the modified silicone-containing resin liquid are as follows:

[0019] Isosorbide bis(terephthalate), bisphenol A and dibenzoate are added into a reactor, heated and stirred at 150-160° C. for 8-10 minutes to obtain a mixed reaction liquid;

[0020] Add 4-dimethylaminopyridine to the mixed reaction solution, continue heating at 150-160°C for 20-30 minutes, then raise the temperature to 180-190°C and distill under reduced pressure for 40-50 minutes to remove phenol, then raise the temperature to 250-270°C and heat the reaction for 2-3 hours to obtain a crude product;

[0021] The crude product is dissolved in chloroform, and methanol is added for alcohol precipitation, followed by centrifugal separation, washing and drying to obtain a modifier;

[0022] The above-mentioned modifier and silicon-containing resin are added to N,N-dimethylformamide, heated and stirred at 60-70° C. to fully dissolve, and then the N,N-dimethylformamide is removed by rotary evaporation to obtain a modified silicon-containing resin liquid.

[0023] Furthermore, the preparation steps of the silicone resin are as follows:

[0024] Dissolve m-diethynylbenzene and methylphenyldichlorosilane in tetrahydrofuran at a solid-liquid ratio of 1 g: (20-30) mL to obtain a m-diethynylbenzene solution and a methylphenyldichlorosilane solution;

[0025] The above m-diethynylbenzene solution was added to ethylmagnesium bromide, and the mixture was heated under reflux at 60-70°C for 2-3 hours under the protection of nitrogen, and then naturally cooled to room temperature to obtain intermediate A;

[0026] Add the above-mentioned methylphenyldichlorosilane solution to the above-mentioned intermediate A, continue heating and reflux reaction at 60-70°C for 2-3 hours, and naturally cool to room temperature to obtain intermediate B;

[0027] The intermediate B is placed in an ice-water bath at 3-5°C, and acetic acid-toluene solution and hydrochloric acid aqueous solution are added. The intermediate B is then transferred to a centrifuge for centrifugation. The upper organic phase is separated and washed, and the solvent is removed by reduced pressure distillation to obtain a silicon-containing resin.

[0028] Furthermore, the preparation steps of the modified glue are as follows:

[0029] Add bisphenol A dianhydride and diphenyl ether dianhydride to N,N′-dimethylacetamide, heat and stir to mix at 70-80° C. and keep warm to obtain a mixed solution;

[0030] Add 2,4-toluene diisocyanate and isophorone diisocyanate to the above mixed solution, keep warm and stir for 1-2 hours, then raise the temperature to 110-120°C, continue stirring and reacting for 1-2 hours, and naturally cool to room temperature to obtain a matrix glue solution;

[0031] Add the hydroxy-terminated polydimethylsiloxane to the above-mentioned base adhesive, heat and stir at 60-80° C. for 2-4 hours, and naturally cool to room temperature to obtain a modified adhesive.

[0032] Furthermore, the preparation steps of the composite flame retardant material are as follows:

[0033] S3.1: Add tromethamine to 70% ethanol at a solid-liquid ratio of 1 g:(10-12) mL. Heat and stir at 60-70°C until completely dissolved to obtain a tromethamine solution.

[0034] S3.2: Add halloysite nanotubes to the above-mentioned tromosite solution at a solid-liquid ratio of 1 g: (30-40) mL, ultrasonicate for 30-40 minutes, and disperse uniformly to obtain a halloysite nanotube dispersion.

[0035] S3.3: Add phytic acid to the halloysite nanotube dispersion, heat and stir at 60-80° C. for 2-4 hours, centrifuge, wash and dry the precipitate to obtain a composite flame retardant material.

[0036] Furthermore, the volume ratio of ethylmagnesium bromide, m-diethynylbenzene solution and methylphenyldichlorosilane solution is 1:(1.8-2.2):(1.9-2.3).

[0037] Furthermore, the acetic acid-toluene solution is prepared by mixing acetic acid and toluene in a volume ratio of 1:(4-6), and the molar ratio of acetic acid to m-diethynylbenzene is (2-3):1.

[0038] Furthermore, the concentration of the hydrochloric acid aqueous solution is 10%, and the volume ratio of the hydrochloric acid aqueous solution to the acetic acid-toluene solution is 1:(3-5).

[0039] Furthermore, the molar ratio of phytic acid to trombopag is 1:(1.1-1.3).

[0040] A high-heat-resistant copper-clad laminate is prepared by any of the above-mentioned processes for preparing a high-heat-resistant copper-clad laminate.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention first prepares a silicone resin by reacting m-diethynylbenzene and methylphenyldichlorosilane as raw materials, and then uses isosorbide bis(terephthalate), bisphenol A and dibenzoate as raw materials to react under the catalysis of 4-dimethylaminopyridine to prepare a modifier. When the silicone resin is modified by the modifier to prepare a modified silicone resin, the isosorbide bis(terephthalate), bisphenol A and dibenzoate in the modifier form a complex cross-linked structure through an esterification reaction, thereby increasing the glass transition temperature of the silicone resin. The ester bond and cross-linked structure in the modifier can reduce the thermal decomposition of the silicone resin at high temperatures, and the benzene ring and ester group in the modifier can improve the thermal conductivity of the silicone resin, contribute to the uniform distribution of heat, and further improve the heat resistance of the silicone resin. Therefore, after the modified silicone resin is added to the modified adhesive, the heat resistance of the modified adhesive can be effectively improved, thereby achieving the effect of improving the heat resistance of the copper clad laminate.

[0043] 2. The present invention prepares a tromethamine solution by first dissolving tromethamine in an ethanol solution, then uniformly dispersing halloysite nanotubes in the tromethamine solution, and then adding phytic acid for in-situ reaction to prepare a composite flame retardant material, so that the reaction product of tromethamine and phytic acid is coated on the surface of the halloysite nanotubes. On the one hand, since the amino group of tromethamine reacts with the phosphate group of phytic acid to form a stable chemical bond, the surface properties of the halloysite nanotubes can be adjusted and their compatibility with the modified adhesive can be improved. On the other hand, since the product of the reaction of tromethamine and phytic acid can promote the formation of a carbon layer and effectively isolate oxygen and heat, coating it on the surface of the halloysite nanotubes can further improve the flame retardant properties of the halloysite nanotubes. Therefore, after the composite flame retardant material is added to the modified adhesive, the flame retardant properties of the modified adhesive can be effectively improved, thereby ensuring the safety and reliability of the copper clad laminate.

[0044] 3. The present invention first uses bisphenol A dianhydride, diphenyl ether dianhydride, 2,4-toluene diisocyanate and isophorone diisocyanate as raw materials to react to prepare a base glue with good bonding performance, and then uses terminal hydroxyl polydimethylsiloxane to modify the base glue. The terminal hydroxyl groups of the terminal hydroxyl polydimethylsiloxane react with the polar groups of the base glue to introduce hydrophobic groups into the base glue, thereby effectively reducing the water absorption rate of the base glue, preventing it from absorbing water and reducing the adhesion between the copper foil and the polyimide film, and achieving the effect of extending the service life of the copper clad laminate. DETAILED DESCRIPTION

[0045] The following describes in detail a high heat-resistant copper-clad laminate and its preparation process provided by the present invention in conjunction with specific embodiments. It is also noted that, in order to make the embodiments more detailed, the following embodiments are best and preferred embodiments, and those skilled in the art may also adopt other alternative methods for implementation of some known technologies.

[0046] Example 1

[0047] A preparation process for a high heat-resistant copper-clad laminate comprises the following steps:

[0048] Preparation of silicone-containing resin:

[0049] Dissolve m-diethynylbenzene and methylphenyldichlorosilane in tetrahydrofuran at a solid-liquid ratio of 1g:20mL respectively to obtain m-diethynylbenzene solution and methylphenyldichlorosilane solution for standby use. Then add the m-diethynylbenzene solution to ethylmagnesium bromide, and heat under reflux at 60°C for 2h under the protection of nitrogen, and naturally cool to room temperature to obtain intermediate A. Subsequently, add methylphenyldichlorosilane solution to intermediate A, and continue heating under reflux at 60°C for 2h, and naturally cool to room temperature to obtain intermediate B, wherein ethylmagnesium bromide and m-diethynylbenzene solution are 1g:20mL, respectively, to obtain m-diethynylbenzene solution and methylphenyldichlorosilane solution. The volume ratio of the solution and the methylphenyldichlorosilane solution is 1:1.8:1.9. Finally, the intermediate B is placed in a 3°C ice water bath, and an acetic acid-toluene solution and a hydrochloric acid aqueous solution are added. The intermediate B is then transferred to a centrifuge for centrifugation, and the upper organic phase is separated and washed. After the solvent is removed by distillation under reduced pressure, a silicone-containing resin is obtained, wherein the acetic acid-toluene solution is prepared by mixing acetic acid and toluene in a volume ratio of 1:4, and the molar ratio of acetic acid to m-diethynylbenzene is 2:1, the concentration of the hydrochloric acid aqueous solution is 10%, and the volume ratio of the hydrochloric acid aqueous solution to the acetic acid-toluene solution is 1:3;

[0050] Preparation of modified silicone resin liquid:

[0051] 10 parts of isosorbide bis(terephthalate), 1 part of bisphenol A and 16 parts of dibenzoate are added to a reactor, heated and stirred at 150° C. for 8 minutes to obtain a mixed reaction liquid, then 0.01 parts of 4-dimethylaminopyridine are added to the mixed reaction liquid, and the mixture is heated at 150° C. for 20 minutes, then the temperature is raised to 180° C., and the mixture is distilled under reduced pressure for 40 minutes to remove phenol, and then the temperature is raised to 250° C. and heated for reaction for 2 hours to obtain a crude product, which is then dissolved in chloroform and methanol is added for alcohol precipitation, followed by centrifugation, washing and drying to obtain a modifier, and finally the modifier and the above-mentioned 30 parts of silicon-containing resin are added to 55 parts of N,N-dimethylformamide, heated and stirred at 60° C. to fully dissolve, and then rotary evaporated to remove N,N-dimethylformamide to obtain a modified silicon-containing resin liquid;

[0052] Preparation of modified glue:

[0053] 34 parts of bisphenol A dianhydride and 45 parts of diphenyl ether dianhydride are added to 60 parts of N,N′-dimethylacetamide, heated and stirred at 70°C and kept warm to obtain a mixed solution, then 16 parts of 2,4-toluene diisocyanate and 21 parts of isophorone diisocyanate are added to the mixed solution, after keeping warm and stirring for 1 hour, the temperature is raised to 110°C, and the stirring reaction is continued for 1 hour. After naturally cooling to room temperature, a base adhesive solution is obtained. Finally, 20 parts of terminal hydroxyl polydimethylsiloxane are added to the base adhesive solution, heated and stirred at 60°C for 2 hours, and naturally cooled to room temperature to obtain a modified adhesive solution.

[0054] Preparation of composite flame retardant materials:

[0055] Adding tromethamine to a 70% ethanol solution at a solid-liquid ratio of 1 g:10 mL, heating and stirring at 60° C. until completely dissolved to obtain a tromethamine solution, then adding halloysite nanotubes to the tromethamine solution at a solid-liquid ratio of 1 g:30 mL, ultrasonically treating for 30 minutes, and uniformly dispersing to obtain a halloysite nanotube dispersion, finally adding phytic acid to the halloysite nanotube dispersion, heating and stirring at 60° C. for 2 hours, and after centrifugation, washing and drying the precipitate to obtain a composite flame retardant material, wherein the molar ratio of phytic acid to tromethamine is 1:1.1;

[0056] S1: Pretreatment of polyimide film

[0057] The thermosetting polyimide film was placed in a 5% sodium hydroxide aqueous solution at 50°C, kept warm for 3 minutes, taken out and dried to obtain a pretreated polyimide film;

[0058] S2: Preparation of mixed glue

[0059] 20 parts of the modified silicone resin liquid, 45 parts of the modified adhesive liquid and 30 parts of the composite flame retardant material were stirred and mixed to obtain a mixed adhesive liquid;

[0060] S3: Preparing prepreg

[0061] The mixed adhesive solution was applied to the surface of the pretreated polyimide film and baked at 80°C and 130°C for 10 hours and 1 hour, respectively, to obtain a prepreg.

[0062] S4: Hot pressing curing

[0063] Several of the above-mentioned prepregs are stacked together, cut, and then covered with copper foil on one side or both sides. After hot pressing and curing, a high heat-resistant copper-clad laminate is obtained.

[0064] Example 2

[0065] A preparation process for a high heat-resistant copper-clad laminate comprises the following steps:

[0066] Preparation of silicone-containing resin:

[0067] Dissolve m-diethynylbenzene and methylphenyldichlorosilane in tetrahydrofuran at a solid-liquid ratio of 1g:25mL respectively to obtain m-diethynylbenzene solution and methylphenyldichlorosilane solution for standby use. Then add the m-diethynylbenzene solution to ethylmagnesium bromide, and heat under reflux at 65°C for 2.5h under the protection of nitrogen, and naturally cool to room temperature to obtain intermediate A. Subsequently, add methylphenyldichlorosilane solution to intermediate A, and continue to heat under reflux at 65°C for 2.5h, and naturally cool to room temperature to obtain intermediate B, wherein ethylmagnesium bromide, m-diethynylbenzene The volume ratio of the benzene solution to the methylphenyldichlorosilane solution is 1:2:2.1. Finally, the intermediate B is placed in a 4°C ice-water bath, and an acetic acid-toluene solution and a hydrochloric acid aqueous solution are added. The intermediate B is then transferred to a centrifuge for centrifugation, and the upper organic phase is separated and washed. The solvent is removed by distillation under reduced pressure to obtain a silicone-containing resin, wherein the acetic acid-toluene solution is prepared by mixing acetic acid and toluene in a volume ratio of 1:5, and the molar ratio of acetic acid to m-diethynylbenzene is 2.5:1. The concentration of the hydrochloric acid aqueous solution is 10%, and the volume ratio of the hydrochloric acid aqueous solution to the acetic acid-toluene solution is 1:4.

[0068] Preparation of modified silicone resin liquid:

[0069] 11 parts of isosorbide bis(terephthalate), 1.5 parts of bisphenol A and 18 parts of dibenzoate are added to a reactor, heated and stirred at 155° C. for 9 minutes to obtain a mixed reaction liquid, then 0.02 parts of 4-dimethylaminopyridine are added to the mixed reaction liquid, and the mixture is heated at 155° C. for 25 minutes, then the temperature is raised to 185° C., and the mixture is distilled under reduced pressure for 45 minutes to remove phenol, and then the temperature is raised to 260° C. and heated for reaction for 2.5 hours to obtain a crude product, which is then dissolved in chloroform and methanol is added for alcohol precipitation, followed by centrifugation, washing and drying to obtain a modifier, and finally the modifier and the above-mentioned 35 parts of silicone-containing resin are added to 65 parts of N,N-dimethylformamide, heated and stirred at 65° C. to fully dissolve, and then rotary evaporated to remove N,N-dimethylformamide to obtain a modified silicone-containing resin liquid;

[0070] Preparation of modified glue:

[0071] 38 parts of bisphenol A dianhydride and 47 parts of diphenyl ether dianhydride are added to 65 parts of N,N′-dimethylacetamide, heated and stirred at 75° C. and kept warm to obtain a mixed solution, then 18 parts of 2,4-toluene diisocyanate and 22 parts of isophorone diisocyanate are added to the mixed solution, after keeping warm and stirring for 1.5 hours, the temperature is raised to 115° C., and the reaction is continued with stirring for 1.5 hours. After naturally cooling to room temperature, a base adhesive solution is obtained. Finally, 25 parts of terminal hydroxyl polydimethylsiloxane are added to the base adhesive solution, heated and stirred at 70° C. for 3 hours, and naturally cooled to room temperature to obtain a modified adhesive solution.

[0072] Preparation of composite flame retardant materials:

[0073] Adding tromethamine to a 70% ethanol solution at a solid-liquid ratio of 1 g:11 mL, heating and stirring at 65° C. until completely dissolved to obtain a tromethamine solution, then adding halloysite nanotubes to the tromethamine solution at a solid-liquid ratio of 1 g:35 mL, ultrasonically treating for 35 minutes, and uniformly dispersing to obtain a halloysite nanotube dispersion, finally adding phytic acid to the halloysite nanotube dispersion, heating and stirring at 70° C. for 3 hours, and after centrifugation, washing and drying the precipitate to obtain a composite flame retardant material, wherein the molar ratio of phytic acid to tromethamine is 1:1.2;

[0074] S1: Pretreatment of polyimide film

[0075] The thermosetting polyimide film was placed in a 5% sodium hydroxide aqueous solution at 55°C, kept warm for 4 minutes, taken out and dried to obtain a pretreated polyimide film;

[0076] S2: Preparation of mixed glue

[0077] 25 parts of the modified silicone resin liquid, 50 parts of the modified adhesive liquid and 35 parts of the composite flame retardant material were stirred and mixed to obtain a mixed adhesive liquid;

[0078] S3: Preparing prepreg

[0079] The mixed adhesive solution was applied to the surface of the pretreated polyimide film and baked at 85°C and 140°C for 11 hours and 1.5 hours, respectively, to obtain a prepreg.

[0080] S4: Hot pressing curing

[0081] Several of the above-mentioned prepregs are stacked together, cut, and then covered with copper foil on one side or both sides. After hot pressing and curing, a high heat-resistant copper-clad laminate is obtained.

[0082] Example 3

[0083] A preparation process for a high heat-resistant copper-clad laminate comprises the following steps:

[0084] Preparation of silicone-containing resin:

[0085] Dissolve m-diethynylbenzene and methylphenyldichlorosilane in tetrahydrofuran at a solid-liquid ratio of 1g:30mL respectively to obtain m-diethynylbenzene solution and methylphenyldichlorosilane solution for standby use. Then add the m-diethynylbenzene solution to ethylmagnesium bromide, and heat under reflux at 70°C for 3h under the protection of nitrogen, and naturally cool to room temperature to obtain intermediate A. Subsequently, add methylphenyldichlorosilane solution to intermediate A, and continue to heat under reflux at 70°C for 3h, and naturally cool to room temperature to obtain intermediate B, wherein ethylmagnesium bromide and m-diethynylbenzene solution are 1g:30mL, respectively, to obtain m-diethynylbenzene solution and methylphenyldichlorosilane solution. The volume ratio of the solution and the methylphenyldichlorosilane solution is 1:2.2:2.3. Finally, the intermediate B is placed in an ice-water bath at 5°C, and an acetic acid-toluene solution and a hydrochloric acid aqueous solution are added. The intermediate B is then transferred to a centrifuge for centrifugation, and the upper organic phase is separated and washed. After the solvent is removed by distillation under reduced pressure, a silicon-containing resin is obtained, wherein the acetic acid-toluene solution is prepared by mixing acetic acid and toluene in a volume ratio of 1:6, and the molar ratio of acetic acid to m-diethynylbenzene is 3:1, the concentration of the hydrochloric acid aqueous solution is 10%, and the volume ratio of the hydrochloric acid aqueous solution to the acetic acid-toluene solution is 1:5;

[0086] Preparation of modified silicone resin liquid:

[0087] 12 parts of isosorbide bis(terephthalate), 2 parts of bisphenol A and 20 parts of dibenzoate are added to a reactor, heated and stirred at 160° C. for 10 minutes to obtain a mixed reaction liquid, then 0.03 parts of 4-dimethylaminopyridine is added to the mixed reaction liquid, and the mixture is heated at 160° C. for 30 minutes, then the temperature is raised to 190° C., and the mixture is distilled under reduced pressure for 50 minutes to remove phenol, and then the temperature is raised to 270° C. and heated for reaction for 3 hours to obtain a crude product, which is then dissolved in chloroform and methanol is added for alcohol precipitation, followed by centrifugation, washing and drying to obtain a modifier, and finally the modifier and the above-mentioned 40 parts of silicone-containing resin are added to 75 parts of N,N-dimethylformamide, heated and stirred at 70° C. to fully dissolve, and then rotary evaporated to remove N,N-dimethylformamide to obtain a modified silicone-containing resin liquid;

[0088] Preparation of modified glue:

[0089] 42 parts of bisphenol A dianhydride and 50 parts of diphenyl ether dianhydride are added to 70 parts of N,N′-dimethylacetamide, heated and stirred at 80° C. and kept warm to obtain a mixed solution, then 20 parts of 2,4-toluene diisocyanate and 23 parts of isophorone diisocyanate are added to the mixed solution, after keeping warm and stirring for 2 hours, the temperature is raised to 120° C., and the reaction is continued with stirring for 2 hours. After naturally cooling to room temperature, a base adhesive solution is obtained. Finally, 30 parts of hydroxyl-terminated polydimethylsiloxane are added to the base adhesive solution, heated and stirred at 80° C. for 4 hours, and naturally cooled to room temperature to obtain a modified adhesive solution.

[0090] Preparation of composite flame retardant materials:

[0091] Triamcinol was added to a 70% ethanol solution at a solid-liquid ratio of 1 g:12 mL, heated and stirred at 70° C. until completely dissolved to obtain a triamcinol solution, and then halloysite nanotubes were added to the triamcinol solution at a solid-liquid ratio of 1 g:40 mL. The mixture was ultrasonically treated for 40 minutes and uniformly dispersed to obtain a halloysite nanotube dispersion. Finally, phytic acid was added to the halloysite nanotube dispersion, heated and stirred at 80° C. for 4 hours, and after centrifugation, the precipitate was washed and dried to obtain a composite flame retardant material, wherein the molar ratio of phytic acid to triamcinol was 1:1.3.

[0092] S1: Pretreatment of polyimide film

[0093] The thermosetting polyimide film was placed in a 5% sodium hydroxide aqueous solution at 60°C, kept warm for 5 minutes, taken out and dried to obtain a pretreated polyimide film;

[0094] S2: Preparation of mixed glue

[0095] 30 parts of the modified silicone resin liquid, 55 parts of the modified adhesive liquid and 40 parts of the composite flame retardant material were stirred and mixed to obtain a mixed adhesive liquid;

[0096] S3: Preparing prepreg

[0097] The mixed adhesive solution was applied to the surface of the pretreated polyimide film and baked at 90°C and 150°C for 12 hours and 2 hours, respectively, to obtain a prepreg.

[0098] S4: Hot pressing curing

[0099] Several of the above-mentioned prepregs are stacked together, cut, and then covered with copper foil on one side or both sides. After hot pressing and curing, a high heat-resistant copper-clad laminate is obtained.

[0100] Performance testing:

[0101] 1. The heat resistance (solder immersion resistance, 288°C) and peel strength of the high heat-resistant copper clad laminates prepared in Examples 1-3 were tested according to GB / T4723-1992. The results are shown in Table 1.

[0102] 2. The flame retardant properties of the high heat-resistant copper clad laminates prepared in Examples 1-3 were tested according to the GB / T2406.2 oxygen index method. The results are shown in Table 1.

[0103] 3. The water absorption of the high heat-resistant copper clad laminates prepared in Examples 1-3 was tested according to IPC-TM-650 2.6.2.1. The results are shown in Table 1.

[0104] Table 1: Summary of performance test results of Examples 1-3

[0105]

[0106] Comparative Example 1

[0107] The difference between Comparative Example 1 and Example 1 is that the modified silicone resin liquid in the mixed glue solution is removed, and then the performance test is carried out according to the performance test method in Example 1. The results are shown in Table 2 below.

[0108] Table 2: Comparative Example 1 and Example 1 Performance Test Results Comparison

[0109]

[0110] As can be seen from Table 2, the copper clad laminate prepared in Comparative Example 1 without adding the modified silicone-containing resin liquid has a solder immersion resistance time in a 288°C solder liquid of about 38 minutes, which is lower than that in Example 1. It can be seen that the silicone-containing resin is first prepared by reacting m-diethynylbenzene and methylphenyldichlorosilane as raw materials, and then isosorbide bis(terephthalate), bisphenol A and dibenzoate as raw materials, and reacting under the catalysis of 4-dimethylaminopyridine to prepare the modifier. When the silicone-containing resin is modified by the modifier to prepare the modified silicone-containing resin, the modifier can improve the thermal conductivity of the silicone-containing resin, contribute to the uniform distribution of heat, and further improve the heat resistance of the silicone-containing resin. Therefore, after the modified silicone-containing resin is added to the modified glue, the heat resistance of the modified glue can be effectively improved, thereby achieving the effect of improving the heat resistance of the copper clad laminate.

[0111] Comparative Example 2

[0112] The difference between Comparative Example 2 and Example 1 is that the composite flame retardant material in the mixed glue solution is removed, and then the performance test is performed according to the performance test method in Example 1. The results are shown in Table 3 below.

[0113] Comparative Example 3

[0114] The difference between Comparative Example 3 and Example 1 is that the composite flame retardant material in the mixed glue is replaced with an equal amount of halloysite nanotubes, and then the performance test is carried out according to the performance test method in Example 1. The results are shown in Table 3 below.

[0115] Table 3: Comparative Example 2-3 and Example 1 Performance Test Results Comparison

[0116]

[0117] As can be seen from Table 3, the limiting oxygen index of the copper clad laminate obtained in Comparative Example 2 when no composite flame retardant material is added is about 25.1%, while in Comparative Example 3, after the composite flame retardant material is replaced with an equal amount of halloysite nanotubes, the limiting oxygen index of the copper clad laminate obtained is about 30.4%, which is higher than that of Comparative Example 2, but still lower than that of Example 1. It can be seen that by first dissolving trombopag in an ethanol solution to prepare a trombopag solution, then uniformly dispersing the halloysite nanotubes in the trombopag solution, and then adding phytic acid for in-situ reaction to prepare a composite flame retardant material, the reaction product of trombopag and phytic acid contains Coated on the surface of the halloysite nanotubes, on the one hand, since the amino group of tropol reacts with the phosphate group of phytic acid to form a stable chemical bond, the surface properties of the halloysite nanotubes can be adjusted and their compatibility with the modified adhesive can be improved. On the other hand, since the product of the reaction between tropol and phytic acid can promote the formation of a carbon layer and effectively isolate oxygen and heat, coating it on the surface of the halloysite nanotubes can further improve the flame retardant properties of the halloysite nanotubes. Therefore, after the composite flame retardant material is added to the modified adhesive, the flame retardant properties of the modified adhesive can be effectively improved, thereby ensuring the safety and reliability of the copper clad laminate.

[0118] Comparative Example 4

[0119] The difference between Comparative Example 4 and Example 1 is that the modified adhesive in the mixed adhesive is removed, and then the performance test is performed according to the performance test method in Example 1. The results are shown in Table 4 below.

[0120] Comparative Example 5

[0121] The difference between this comparative example 5 and Example 1 is that the modified adhesive in the mixed adhesive is replaced with an equal amount of base adhesive, and then the performance test is carried out according to the performance test method in Example 1. The results are shown in Table 4 below.

[0122] Table 4: Comparative Example 4-5 and Example 1 Performance Test Results Comparison

[0123]

[0124] As can be seen from Table 4, after the modified glue in the mixed glue is removed in Comparative Example 4, the peel strength of the copper clad laminate obtained is about 1.65 N / mm, which is lower than that in Example 1. It can be seen that the base glue with good bonding performance is first prepared by reacting bisphenol A dianhydride, diphenyl ether dianhydride, 2,4-toluene diisocyanate and isophorone diisocyanate as raw materials, and then coating the base glue on the surface of the polyimide film, which can effectively improve the bonding performance between the polyimide film and the copper foil;

[0125] In Comparative Example 5, after the modified glue was replaced with an equal amount of base glue, the water absorption rate of the prepared copper clad laminate was about 1.08%, which was higher than that in Example 1. It can be seen that by modifying the base glue with terminal hydroxyl polydimethylsiloxane, the hydrophobic group was introduced into the base glue through the reaction of the terminal hydroxyl group of the terminal hydroxyl polydimethylsiloxane with the polar group of the base glue, thereby effectively reducing the water absorption rate of the base glue, preventing its water absorption from reducing the adhesion between the copper foil and the polyimide film, and achieving the effect of extending the service life of the copper clad laminate.

[0126] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A process for preparing a high heat-resistant copper-clad laminate, characterized in that: The steps include: S1: Pretreatment of polyimide film, The thermosetting polyimide film is placed in a 5% sodium hydroxide aqueous solution at 50-60° C., and after being kept warm and soaked for 3-5 minutes, taken out and dried to obtain a pretreated polyimide film; S2: prepare mixed glue solution, The modified silicone-containing resin liquid, the modified adhesive liquid and the composite flame retardant material are stirred and mixed uniformly to obtain a mixed adhesive liquid; S3: Preparing a prepreg, The mixed adhesive is applied to the surface of the pretreated polyimide film, and baked at 80-90°C and 130-150°C for 10-12h and 1-2h, respectively, to obtain a prepreg; S4: hot pressing curing, Several prepregs are stacked together, cut, and then covered with copper foil on one or both sides, and subjected to heat-pressing curing to obtain a high heat-resistant copper-clad laminate; The mixed adhesive solution includes, by weight: 20-30 parts of modified silicone resin solution, 45-55 parts of modified adhesive solution and 30-40 parts of composite flame retardant material; The raw material components required for the modified silicone-containing resin liquid include, by weight: 10-12 parts of isosorbide bis(terephthalate), 1-2 parts of bisphenol A, 16-20 parts of dibenzoate, 0.01-0.03 parts of 4-dimethylaminopyridine, 30-40 parts of silicone-containing resin and 55-75 parts of N,N-dimethylformamide; The raw material components required for the modified adhesive solution include, by weight: 16-20 parts of 2,4-toluene diisocyanate, 21-23 parts of isophorone diisocyanate, 34-42 parts of bisphenol A dianhydride, 45-50 parts of diphenyl ether dianhydride, 20-30 parts of terminal hydroxyl polydimethylsiloxane and 60-70 parts of N,N′-dimethylacetamide.

2. The process for preparing a high heat-resistant copper-clad laminate according to claim 1, characterized in that: The preparation steps of the modified silicone-containing resin liquid are as follows: Add isosorbide bis(terephthalate), bisphenol A and dibenzoate into a reactor, heat and stir at 150-160° C. for 8-10 minutes to obtain a mixed reaction liquid; Add 4-dimethylaminopyridine to the mixed reaction liquid, continue heating at 150-160°C for 20-30 min, then raise the temperature to 180-190°C, distill under reduced pressure for 40-50 min to remove phenol, then raise the temperature to 250-270°C, and heat to react for 2-3 h to obtain a crude product; The crude product is dissolved in chloroform, and methanol is added for alcohol precipitation, and the modified agent is obtained by centrifugal separation, washing and drying; The above-mentioned modifier and silicon-containing resin are added to N,N-dimethylformamide, heated and stirred at 60-70° C. to fully dissolve, and then the N,N-dimethylformamide is removed by rotary evaporation to obtain a modified silicon-containing resin liquid.

3. The process for preparing a high heat-resistant copper-clad laminate according to claim 2, characterized in that: The preparation steps of silicone resin are as follows: Dissolve m-diethynylbenzene and methylphenyldichlorosilane in tetrahydrofuran at a solid-liquid ratio of 1 g: (20-30) mL to obtain a m-diethynylbenzene solution and a methylphenyldichlorosilane solution; The above m-diethynylbenzene solution was added to ethylmagnesium bromide, and the mixture was heated to reflux at 60-70°C for 2-3 hours under the protection of nitrogen, and then naturally cooled to room temperature to obtain intermediate A; Add the above-mentioned methylphenyldichlorosilane solution to the above-mentioned intermediate A, continue heating and reflux reaction at 60-70° C. for 2-3 hours, and naturally cool to room temperature to obtain intermediate B; The intermediate B is placed in an ice-water bath at 3-5°C, and acetic acid-toluene solution and hydrochloric acid aqueous solution are added, then transferred to a centrifuge for centrifugation, and the upper organic phase is separated and washed, and the solvent is removed by reduced pressure distillation to obtain a silicon-containing resin.

4. The process for preparing a high heat-resistant copper-clad laminate according to claim 1, characterized in that: The preparation steps of the modified glue solution are as follows: Add bisphenol A dianhydride and diphenyl ether dianhydride into N,N′-dimethylacetamide, heat and stir to mix at 70-80° C. and keep warm to obtain a mixed solution; Add 2,4-toluene diisocyanate and isophorone diisocyanate to the mixed solution, keep warm and stir for 1-2 hours, then raise the temperature to 110-120°C, continue stirring and reacting for 1-2 hours, and naturally cool to room temperature to obtain a matrix glue solution; Add terminal hydroxyl polydimethylsiloxane to the above-mentioned base adhesive solution, heat and stir at 60-80° C. for 2-4 hours, and naturally cool to room temperature to obtain a modified adhesive solution.

5. The process for preparing a high heat-resistant copper-clad laminate according to claim 1, characterized in that: The preparation steps of the composite flame retardant material are as follows: Add tromethamine to 70% ethanol solution at a solid-liquid ratio of 1 g: (10-12) mL, heat and stir at 60-70° C. until completely dissolved, to obtain a tromethamine solution; Add halloysite nanotubes to the above-mentioned tromethamine solution at a solid-liquid ratio of 1 g: (30-40) mL, perform ultrasonic treatment for 30-40 min, and obtain a halloysite nanotube dispersion after uniform dispersion; Add phytic acid to the halloysite nanotube dispersion, heat and stir at 60-80° C. for 2-4 hours, and wash and dry the precipitate after centrifugal separation to obtain a composite flame retardant material.

6. The process for preparing a high heat-resistant copper-clad laminate according to claim 3, characterized in that: The volume ratio of ethylmagnesium bromide, m-diethynylbenzene solution and methylphenyldichlorosilane solution is 1:(1.8-2.2):(1.9-2.3).

7. The process for preparing a high heat-resistant copper-clad laminate according to claim 3, characterized in that: The acetic acid-toluene solution is prepared by mixing acetic acid and toluene in a volume ratio of 1:(4-6), and the molar ratio of acetic acid to m-diethynylbenzene is (2-3):

1.

8. The process for preparing a high heat-resistant copper-clad laminate according to claim 3, characterized in that: The concentration of the hydrochloric acid aqueous solution is 10%, and the volume ratio of the hydrochloric acid aqueous solution to the acetic acid-toluene solution is 1:(3-5).

9. The process for preparing a high heat-resistant copper-clad laminate according to claim 5, characterized in that: The molar ratio of phytic acid to tromethamine is 1:(1.1-1.3).

10. A high heat-resistant copper-clad laminate, characterized in that: It is prepared by the preparation process of a high heat-resistant copper-clad laminate as described in any one of claims 1 to 9.

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