Preparation process of high-oxidation-resistance circuit board

Abstract

The application provides a preparation process of a high-oxidation-resistance circuit board, and belongs to the technical field of printed circuit boards; the process comprises the following steps: pretreating a copper foil; performing surface oxidation-resistance treatment; preparing a composite board; and preparing a high-oxidation-resistance circuit board.The formaldehyde resin is generated through the addition condensation reaction of the chlormequin diterpene polyphenol in the Taraxacum mongolicum Hand.-Mazz and formaldehyde under the catalysis of ammonia water, meanwhile, the zinc sulfate heptahydrate is converted into zinc oxide nanoparticles through "zinc-ammonia complex-zinc hydroxide-zinc oxide", and the zinc oxide nanoparticles are driven to form zinc oxide composite microspheres through surface tension and the force between zinc oxide and formaldehyde resin, and the zinc oxide composite microspheres are added into the protective layer resin, so that the oxidation resistance of the protective layer resin and the oxidation resistance of the circuit board are effectively improved, in addition, the uniform dispersion of the zinc oxide nanoparticles is facilitated, and the local oxidation of the protective layer in the use process is prevented.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit boards, in particular to a preparation process of high-oxidation-resistant circuit board. BACKGROUND

[0002] With the rapid development of electronic technology, the performance and quality of circuit boards, as the core components of electronic devices, directly affect the reliability and stability of electronic devices. Among the many types of circuit boards, the demand for high-oxidation-resistant circuit boards is increasing. The use environment of electronic devices is becoming increasingly complex, including high temperature, high humidity, high corrosion and other harsh conditions, which puts higher requirements on the oxidation resistance of circuit boards.

[0003] Most of the circuit boards on the market are prone to surface oxidation, metal layer corrosion and other problems when facing oxidation environment, thereby reducing the conductivity and service life of the circuit board. For example, in some high-temperature and high-humidity environments, the copper foil and other metal parts on the circuit board will gradually be oxidized, resulting in increased circuit resistance and unstable signal transmission. Some existing oxidation-resistant treatment methods, such as coating an oxidation-resistant agent and electroplating, can improve the oxidation resistance of the circuit board to some extent, but the electroplating process may generate wastewater, waste gas and other pollutants, causing great pressure on the environment, and the coating method may result in poor local oxidation resistance due to the unevenness of the coating.

[0004] Therefore, a preparation process of high-oxidation-resistant circuit board with uniform resistance is needed to prolong the service life of the circuit board. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a preparation process of high-oxidation-resistant circuit board.

[0006] A preparation process of high-oxidation-resistant circuit board, comprising the following steps:

[0007] S1: pretreating copper foil

[0008] The copper foil is immersed in anhydrous ethanol and ultrasonically cleaned for 3-5 min, then taken out and ultrasonically cleaned with deionized water for 3-5 min to obtain pretreated copper foil.

[0009] S2: surface oxidation-resistant treatment

[0010] The pretreated copper foil is immersed in an oxidation-resistant treatment agent and placed in a rotary evaporator, the water bath temperature is set to 25-35℃, and the surface is plated for 20-30 min, then taken out, cleaned with deionized water, and baked at 100-110℃ for 10-20 min to obtain oxidation-resistant treated copper foil.

[0011] S3: preparing a composite board

[0012] The glass fiber cloth is immersed in the epoxy resin solution, dried to form a substrate layer, then the substrate layer is attached to one side of the above antioxidant treated copper foil to form a conductive layer, and then a protective layer resin is coated on the other side of the antioxidant treated copper foil, dried and cured to form a protective layer, thereby obtaining a composite board with a structure of "substrate layer-conductive layer-protective layer";

[0013] S4: preparing a high-oxidation-resistant circuit board

[0014] The above composite board is subjected to post-treatment to obtain a high-oxidation-resistant circuit board.

[0015] Further, the preparation steps of the antioxidant treatment agent are as follows:

[0016] Alkyl benzimidazole and polyvinyl alcohol are added to deionized water, fully stirred and dissolved to obtain A liquid;

[0017] Gallic acid and triethanolamine are added to the above A liquid, continuously stirred and fully dissolved to obtain B liquid;

[0018] Octylphenol polyoxyethylene ether is added to the above B liquid, fully mixed and uniform, then defoamed to obtain an antioxidant treatment agent.

[0019] Further, the preparation steps of the protective layer resin are as follows:

[0020] The ceramic-based modifier is dissolved in N,N-dimethylformamide according to a solid-liquid ratio of 1g:(20-30)mL, then hydantoin epoxy resin is added, stirred and mixed for 2-3h, then zinc oxide composite microspheres are added, fully stirred and dispersed to obtain a mixed dispersion liquid;

[0021] The tetramethyl bisphenol F type cyanate is added to the above mixed dispersion liquid, heated and stirred at 100-120℃ for 3-4h, then vacuum defoamed to obtain a protective layer resin.

[0022] Further, the preparation steps of the ceramic-based modifier are as follows:

[0023] The tetraethyl orthosilicate is added to anhydrous ethanol according to a volume ratio of 1:(25-35), stirred at room temperature for 3-4h, fully dissolved to obtain a tetraethyl orthosilicate solution;

[0024] Diphenyl methane diisocyanate and triethylamine are added to the above tetraethyl orthosilicate solution, stirred for 4-6h, then zirconium n-propionate is added, continuously stirred for 10-12h, then placed in a vacuum drying oven for vacuum drying to obtain a ceramic-based modifier.

[0025] Further, the preparation steps of the zinc oxide composite microspheres are as follows:

[0026] Formaldehyde and polyethylene glycol are added into deionized water according to a solid-liquid ratio (7-8) g:1 g:(500-600) mL, and after stirring and mixing uniformly, ammonia water is added to adjust the pH to 9-10, to obtain a mixed solution;

[0027] Taraxacum officinale F.Bolos et Vigo root polyphenol and zinc sulfate heptahydrate are added into the above mixed solution according to a solid-liquid ratio 1 g:(0.6-0.8) g:(200-300) mL, and after stirring and mixing uniformly, a mixed reaction liquid is obtained.

[0028] The above mixed reaction liquid is transferred into a reaction kettle, heated at 160-180 DEG C for 5-6 h to perform continuous hydrothermal reaction, and after natural cooling to room temperature, centrifugation, washing and drying, and aging at 140-150 DEG C for 1-2 h, zinc oxide composite microspheres are obtained.

[0029] Further, the concentration of each component in the antioxidant treatment agent comprises: 1-1.5 g / L alkyl benzimidazole, 5.5-6.5 g / L polyvinyl alcohol, 5.8-6.2 g / L gallic acid, 5-6 g / L triethanolamine and 4.5-5.5 g / L octylphenol polyoxyethylene ether.

[0030] Further, the mass ratio of the hydantoin epoxy resin to the ceramic-based modifier is (10-12):1.

[0031] Further, the mass ratio of the zinc oxide composite microspheres to the hydantoin epoxy resin is 1:(8-10), and the mass ratio of the tetramethyl bisphenol F type cyanate to the hydantoin epoxy resin is (3-4):1.

[0032] Further, the volume ratio of the diphenyl methane diisocyanate solution to the tetraethyl orthosilicate solution is 1:(20-30), and the mass ratio of the triethylamine to the diphenyl methane diisocyanate is 1:(45-50).

[0033] Further, the mass ratio of the zirconium n-propionate to the diphenyl methane diisocyanate is (3.4-3.6):1.

[0034] Compared with the prior art, the beneficial effects of the present application are:

[0035] 1、The application is characterized in that the formaldehyde resin is generated by the addition condensation reaction of the polyphenol in the root of Taraxacum Kok-saghyz under the catalysis of ammonia water, at the same time, the zinc oxide nanoparticles are formed through the "zinc-ammonia complex-zinc hydroxide-zinc oxide" of the zinc sulfate heptahydrate, and the zinc oxide composite microspheres are formed through the "self-assembly" driven by the surface tension and the force between the zinc oxide and the formaldehyde resin, the zinc oxide composite microspheres are added into the protective layer resin, the zinc oxide can capture and neutralize the free radicals generated in the use process of the protective layer resin, so that the antioxidant performance of the protective layer resin and the circuit board can be effectively improved, in addition, due to the coating effect of the formaldehyde resin, the compatibility of the nano zinc oxide and the epoxy resin can be improved, which is beneficial to the uniform dispersion of the nano zinc oxide and prevents the local oxidation problem of the protective layer in the use process.

[0036] 2、The application is characterized in that the tetraethyl orthosilicate is dissolved in anhydrous ethanol, then the diphenyl methane diisocyanate, triethylamine and zirconium n-propionate are added, the mixture is fully stirred and vacuum dried to prepare the ceramic-based modifier with good dispersibility, and the ceramic-based modifier is added into the hydantoin epoxy resin, so that the ceramic-based modifier can be uniformly dispersed in the hydantoin epoxy resin, and the silicon and zirconium elements in the ceramic-based modifier can cross-link with the hydroxyl and epoxy groups in the hydantoin epoxy resin to form a more complex three-dimensional network structure, so that the thermal stability of the hydantoin epoxy resin can be effectively improved, and the thermal stability of the protective layer is further improved.

[0037] 3、The application is characterized in that the antioxidant treatment agent is prepared by taking alkyl benzimidazole and polyvinyl alcohol as the film forming agent, taking gallic acid as the antioxidant, taking triethanolamine as the complexing agent, and cooperating with the surfactant octylphenol polyoxyethylene ether, after the copper foil is immersed in the antioxidant treatment agent, a stable complex film can be grown on the surface of the copper foil, the copper foil is isolated from the air, so that the copper foil is prevented from being oxidized by the air, in addition, the complex film grown on the surface of the copper foil can react with the functional groups in the protective layer resin, so that the adhesion between the resin and the surface of the copper foil is enhanced, and the protective layer is prevented from falling off. DETAILED DESCRIPTION

[0038] The preparation process of the high-antioxidant circuit board provided by the application is described in detail below. It should be noted that, in order to make the examples more detailed, the following examples are the best and preferred examples, and other alternative ways can also be used by those skilled in the art.

[0039] Example 1

[0040] The preparation process of the high-antioxidant circuit board comprises the following steps:

[0041] (1) Preparation of antioxidant treatment agent:

[0042] The alkyl benzimidazole and polyvinyl alcohol are added into deionized water, fully stirred and dissolved to obtain liquid A, then gallic acid and triethanolamine are added into liquid A, continuously stirred and fully dissolved to obtain liquid B, then octylphenol polyoxyethylene ether is added into liquid B, fully mixed and uniform, and then defoamed to obtain the antioxidant treatment agent, wherein the concentration of each component in the antioxidant treatment agent includes: 1 g / L alkyl benzimidazole, 5.5 g / L polyvinyl alcohol, 5.8 g / L gallic acid, 5 g / L triethanolamine and 4.5 g / L octylphenol polyoxyethylene ether;

[0043] (2) Preparation of ceramic-based modifier:

[0044] The tetraethyl orthosilicate is added into anhydrous ethanol at a volume ratio of 1:25, stirred at room temperature for 3 h, fully dissolved to obtain a tetraethyl orthosilicate solution, then diphenyl methane diisocyanate and triethylamine are added into the tetraethyl orthosilicate solution, stirred for 4 h, then zirconium n-propionate is added, continuously stirred for 10 h, and then placed in a vacuum drying box for vacuum drying to obtain the ceramic-based modifier, wherein the volume ratio of diphenyl methane diisocyanate to the tetraethyl orthosilicate solution is 1:20, the mass ratio of triethylamine to diphenyl methane diisocyanate is 1:45, and the mass ratio of zirconium n-propionate to diphenyl methane diisocyanate is 3.4:1;

[0045] (3) Preparation of zinc oxide composite microspheres:

[0046] The formaldehyde and polyethylene glycol are added into deionized water at a solid-liquid ratio of 7 g:1 g:500 mL, stirred and mixed uniformly, then ammonia water is added to adjust the pH to 9 to obtain a mixed solution, then the blue gel taraxacum mongolicum hendg root polyphenol and zinc sulfate heptahydrate are added into the mixed solution at a solid-liquid ratio of 1 g:0.6 g:200 mL, stirred and mixed uniformly to obtain a mixed reaction liquid, finally, the mixed reaction liquid is transferred into a reaction kettle, heated at 160℃ for 5 h for continuous hydrothermal reaction, naturally cooled to room temperature, and then centrifuged, washed and dried, and then aged at 140℃ for 1 h to obtain the zinc oxide composite microspheres;

[0047] (4) Preparation of protective layer resin:

[0048] The ceramic-based modifier is dissolved in N,N-dimethylformamide at a solid-liquid ratio of 1 g:20 mL, then the hydantoin epoxy resin is added, stirred and mixed for 2 h, then the zinc oxide composite microspheres are added, fully stirred and dispersed to obtain a mixed dispersion liquid, wherein the mass ratio of the hydantoin epoxy resin to the ceramic-based modifier is 10:1, and the mass ratio of the zinc oxide composite microspheres to the hydantoin epoxy resin is 1:8, then the tetramethyl bisphenol F type cyanate is added into the mixed dispersion liquid, heated and stirred at 100℃ for 3 h, and then vacuum defoamed to obtain the protective layer resin, wherein the mass ratio of the tetramethyl bisphenol F type cyanate to the hydantoin epoxy resin is 3:1;

[0049] S1: Pretreatment of copper foil

[0050] The copper foil is immersed in anhydrous ethanol and ultrasonically cleaned for 3 min, and after being taken out, it is ultrasonically cleaned with deionized water for 3 min to obtain a pretreated copper foil;

[0051] S2: Surface antioxidant treatment

[0052] The pretreated copper foil is immersed in an antioxidant treatment agent, and then placed in a rotary evaporator, with a water bath temperature of 25℃, and rotary evaporation is performed for 20 min to form a surface film. After being taken out, it is cleaned with deionized water and baked at 100℃ for 10 min to obtain an antioxidant-treated copper foil;

[0053] S3: Preparation of composite board

[0054] The glass fiber cloth is immersed in an epoxy resin solution, dried to form a substrate layer, and then attached to one side of the antioxidant-treated copper foil to form a conductive layer. A protective layer of resin is then applied to the other side of the antioxidant-treated copper foil, and after drying and curing, a protective layer is formed, resulting in a composite board with a "substrate layer-conductive layer-protective layer" structure;

[0055] S4: Preparation of high-oxidation-resistant circuit board

[0056] The composite board is subjected to post-treatment to obtain a high-oxidation-resistant circuit board.

[0057] Example 2

[0058] A process for preparing a high-oxidation-resistant circuit board, comprising the following steps:

[0059] (1) Preparation of antioxidant treatment agent:

[0060] Alkyl benzimidazole and polyvinyl alcohol are added to deionized water and thoroughly stirred and dissolved to obtain A liquid. Gallic acid and triethanolamine are then added to the A liquid and continue to be stirred and thoroughly dissolved to obtain B liquid. Octylphenol polyoxyethylene ether is then added to the B liquid and thoroughly mixed and degassed to obtain an antioxidant treatment agent. The concentrations of the components in the antioxidant treatment agent include 1.3 g / L alkyl benzimidazole, 6 g / L polyvinyl alcohol, 6 g / L gallic acid, 5.5 g / L triethanolamine, and 5 g / L octylphenol polyoxyethylene ether;

[0061] (2) Preparation of ceramic-based modifier:

[0062] The tetraethyl orthosilicate is added into anhydrous ethanol at a volume ratio of 1:30, stirred at room temperature for 3.5 hours, fully dissolved to obtain a tetraethyl orthosilicate solution, then the diphenyl methane diisocyanate and triethylamine are added into the tetraethyl orthosilicate solution, stirred for 5 hours, then the zirconium n-propionate is added, continue to stir for 11 hours, then placed in a vacuum drying box for vacuum drying to obtain the ceramic-based modifier, wherein the volume ratio of the diphenyl methane diisocyanate to the tetraethyl orthosilicate solution is 1:25, the mass ratio of the triethylamine to the diphenyl methane diisocyanate is 1:48, and the mass ratio of the zirconium n-propionate to the diphenyl methane diisocyanate is 3.5:1;

[0063] (3) Preparation of zinc oxide composite microspheres:

[0064] The formaldehyde and polyethylene glycol are added into the deionized water at a solid-liquid ratio of 7.5g:1g:550mL, stirred and mixed uniformly, then the ammonia water is added to adjust the pH to 9.5 to obtain a mixed solution, then the blue gel taraxacum root polyphenol and zinc sulfate heptahydrate are added into the mixed solution at a solid-liquid ratio of 1g:0.7g:250mL, stirred and mixed uniformly to obtain a mixed reaction liquid, finally, the mixed reaction liquid is transferred into a reaction kettle, heated at 170℃ for 5.5 hours for continuous hydrothermal reaction, naturally cooled to room temperature, then centrifuged, washed and dried, and then aged at 145℃ for 1.5 hours to obtain the zinc oxide composite microspheres;

[0065] (4) Preparation of protective layer resin:

[0066] The ceramic-based modifier is dissolved in N,N-dimethylformamide at a solid-liquid ratio of 1g:25mL, then the hytrel epoxy resin is added, stirred and mixed for 2.5 hours, then the zinc oxide composite microspheres are added, fully stirred and dispersed to obtain a mixed dispersion liquid, wherein the mass ratio of the hytrel epoxy resin to the ceramic-based modifier is 11:1, and the mass ratio of the zinc oxide composite microspheres to the hytrel epoxy resin is 1:9, then the tetramethyl bisphenol F type cyanate is added into the mixed dispersion liquid, heated and stirred at 110℃ for 3.5 hours, then vacuum degassed to obtain the protective layer resin, wherein the mass ratio of the tetramethyl bisphenol F type cyanate to the hytrel epoxy resin is 3.5:1;

[0067] S1: Pretreatment of copper foil

[0068] The copper foil is immersed into anhydrous ethanol, ultrasonically cleaned for 4 minutes, then taken out and ultrasonically cleaned with deionized water for 4 minutes to obtain the pretreated copper foil;

[0069] S2: Surface antioxidant treatment

[0070] Subsequently, the pretreated copper foil is immersed in the anti-oxidation treatment agent, and is placed in a rotary evaporator, with a water bath temperature of 30℃, and is subjected to surface film plating for 25 minutes. After being taken out, the copper foil is cleaned with deionized water, and is baked at 105℃ for 15 minutes to obtain an anti-oxidation treated copper foil.

[0071] S3: Preparation of a composite board

[0072] The glass fiber cloth is immersed in an epoxy resin solution, dried, and then forms a substrate layer. The substrate layer is attached to one side of the anti-oxidation treated copper foil to form a conductive layer. A protective layer resin is coated on the other side of the anti-oxidation treated copper foil, and after drying and curing, a protective layer is formed. A composite board with a "substrate layer-conductive layer-protective layer" structure is obtained.

[0073] S4: Preparation of a high-oxidation-resistant circuit board

[0074] The composite board is subjected to post-treatment to obtain a high-oxidation-resistant circuit board.

[0075] Example 3

[0076] A process for preparing a high-oxidation-resistant circuit board includes the following steps:

[0077] (1) Preparation of an anti-oxidation treatment agent:

[0078] Alkyl benzimidazole and polyvinyl alcohol are added to deionized water, and are fully stirred and dissolved to obtain liquid A. Gallic acid and triethanolamine are then added to liquid A, and are continuously stirred and fully dissolved to obtain liquid B. Octylphenol polyoxyethylene ether is then added to liquid B, and is fully mixed and degassed to obtain an anti-oxidation treatment agent. The concentrations of the components in the anti-oxidation treatment agent include: 1.5 g / L alkyl benzimidazole, 6.5 g / L polyvinyl alcohol, 6.2 g / L gallic acid, 6 g / L triethanolamine, and 5.5 g / L octylphenol polyoxyethylene ether.

[0079] (2) Preparation of a ceramic-based modifier:

[0080] Tetraethyl orthosilicate is added to anhydrous ethanol at a volume ratio of 1:35, and is stirred at room temperature for 4 hours to fully dissolve, to obtain a tetraethyl orthosilicate solution. Diphenyl methane diisocyanate and triethylamine are then added to the tetraethyl orthosilicate solution, and are stirred for 6 hours. Zirconium n-propionate is then added, and is continuously stirred for 12 hours. The mixture is then placed in a vacuum drying oven for vacuum drying to obtain a ceramic-based modifier. The volume ratio of diphenyl methane diisocyanate to the tetraethyl orthosilicate solution is 1:30, the mass ratio of triethylamine to diphenyl methane diisocyanate is 1:50, and the mass ratio of zirconium n-propionate to diphenyl methane diisocyanate is 3.6:1.

[0081] (3) Preparation of zinc oxide composite microspheres:

[0082] Formaldehyde and polyethylene glycol were added into deionized water according to a solid-liquid ratio of 8 g: 1 g: 600 mL, and after stirring and mixing uniformly, ammonia water was added to adjust the pH to 10 to obtain a mixed solution, then the blue gel taraxacum mongolicum hand.-muller polyphenol and zinc sulfate heptahydrate were added into the mixed solution according to a solid-liquid ratio of 1 g: 0.8 g: 300 mL, and after stirring and mixing uniformly, a mixed reaction liquid was obtained, finally, the mixed reaction liquid was transferred into a reaction kettle, and a continuous hydrothermal reaction was carried out at 180 °C for 6 h, and after natural cooling to room temperature, centrifugation, washing and drying, and then curing at 150 °C for 2 h, zinc oxide composite microspheres were obtained;

[0083] (4) Preparation of protective layer resin:

[0084] The ceramic-based modifier was dissolved in N,N-dimethylformamide according to a solid-liquid ratio of 1 g: 30 mL, and then the hydantoin epoxy resin was added, and after stirring and mixing for 3 h, the zinc oxide composite microspheres were added and fully stirred and dispersed to obtain a mixed dispersion liquid, wherein the mass ratio of the hydantoin epoxy resin to the ceramic-based modifier was 12: 1, and the mass ratio of the zinc oxide composite microspheres to the hydantoin epoxy resin was 1: 10, then the tetramethyl bisphenol F type cyanate was added into the mixed dispersion liquid, and after heating and stirring at 120 °C for 4 h and vacuum degassing, the protective layer resin was obtained, wherein the mass ratio of the tetramethyl bisphenol F type cyanate to the hydantoin epoxy resin was 4: 1;

[0085] S1: Pretreatment of copper foil

[0086] The above pretreated copper foil was immersed in anhydrous ethanol and ultrasonically cleaned for 5 min, and after taking it out, it was ultrasonically cleaned with deionized water for 5 min to obtain the pretreated copper foil;

[0087] S2: Surface antioxidant treatment

[0088] The copper foil was immersed in the antioxidant treatment agent, and then placed in a rotary evaporator, and the water bath temperature was set to 35 °C, and the surface was coated for 30 min, and then taken out and cleaned with deionized water, and then baked at 110 °C for 20 min to obtain the antioxidant treated copper foil;

[0089] S3: Preparation of composite board

[0090] The glass fiber cloth was immersed in the epoxy resin solution, dried to form a substrate layer, and then attached to one side of the above antioxidant treated copper foil to form a conductive layer, and then the protective layer resin was coated on the other side of the antioxidant treated copper foil, and after drying and curing, a protective layer was formed, and a composite board with a structure of "substrate layer-conductive layer-protective layer" was obtained;

[0091] S4: Preparation of high-oxidation-resistant circuit board

[0092] The above composite board was subjected to post-treatment to obtain a high-oxidation-resistant circuit board.

[0093] Comparative Example 1

[0094] The difference between Comparative Example 1 and Example 1 is that step (3) is removed, and the zinc oxide composite microspheres in step (4) are removed.

[0095] Comparative Example 2

[0096] The difference between Comparative Example 2 and Example 1 is that the formaldehyde, polyethylene glycol, ammonia water and blue glue taraxacum root polyphenol in step (3) are removed, i.e. the zinc sulfate heptahydrate is directly dissolved in deionized water to carry out hydrothermal reaction to prepare nano zinc oxide, and the zinc oxide composite microspheres in step (4) are replaced by an equal amount of nano zinc oxide.

[0097] Comparative Example 3

[0098] The difference between Comparative Example 3 and Example 1 is that step (2) is removed, and the ceramic-based modifier in step (4) is removed.

[0099] Comparative Example 4

[0100] The difference between Comparative Example 4 and Example 1 is that step S2 is removed, i.e. the surface of the pretreated copper foil is not subjected to antioxidant treatment.

[0101] Performance test:

[0102] 1. The protective layer of the circuit board prepared in Examples 1-3 and Comparative Examples 1-2 was subjected to ultraviolet lamp weathering artificial aging test according to the GB / T 23987-2009 standard, the irradiation temperature was 60℃, the irradiation time was 72h, and the performance of the protective layer before and after aging was evaluated according to the GB / T 1776-2008 standard, and the results are shown in Table 1.

[0103] Table 1: Comparison of antioxidant performance test of protective layer prepared in Examples 1-3 and Comparative Examples 1-2

[0104]

[0105] As shown in Table 1, when no zinc oxide composite microspheres are added in Comparative Example 1, the light loss rate of the prepared protective layer of the circuit board after the artificial aging test is about 36.2%, which is much larger than that of Example 1. When the zinc oxide composite microspheres are replaced by nano zinc oxide in Comparative Example 2, the light loss rate of the prepared protective layer of the circuit board after the artificial aging test is not large compared with Example 1, but local excessive light loss phenomenon occurs. It can be seen that, by the addition condensation reaction of the methanol resin generated by the addition condensation reaction of the chlorogenic taraxacum root polyphenol and formaldehyde under the catalysis of ammonia, and the zinc sulfate heptahydrate, the zinc oxide nanoparticles are formed through the "zinc-ammonia complex-zinc hydroxide-zinc oxide", and the zinc oxide composite microspheres are formed through the "self-assembly" driven by the surface tension and the interaction force between the zinc oxide and the formaldehyde resin. The zinc oxide composite microspheres are added into the protective layer resin. Since the zinc oxide can capture and neutralize the free radicals generated in the use process of the protective layer resin, the antioxidant performance of the protective layer resin can be effectively improved, and the antioxidant performance of the circuit board is improved. In addition, due to the coating effect of the formaldehyde resin, the compatibility of the nano zinc oxide and the epoxy resin is improved, which is beneficial to the uniform dispersion of the nano zinc oxide, and prevents the local oxidation problem of the protective layer in the use process.

[0106] 2. The thermal stability of the protective layer of the circuit board prepared in Examples 1-3 and Comparative Example 3 was tested by a thermal gravimetric analyzer. 5 mg of the protective layer was placed in a crucible, nitrogen was used as the protective gas, the temperature range was 30-500°C, the temperature rising rate was 5°C, the temperature at which the mass loss rate of each protective layer was 5% was tested, and the results are shown in Table 2.

[0107] Table 2: Comparison of the thermal stability test results of the protective layer of Examples 1-3 and Comparative Example 3

[0108]

[0109] As shown in Table 2, when no ceramic-based modifier is added in Comparative Example 3, the temperature at which the mass loss rate of the protective layer of the prepared circuit board is 5% under nitrogen is 395°C, which is lower than that of Example 1. It can be seen that, by dissolving the tetraethyl orthosilicate in anhydrous ethanol, then adding diphenyl methane diisocyanate, triethylamine and zirconium n-propionate, fully stirring and mixing and vacuum drying, a ceramic-based modifier with good dispersibility is prepared. After the ceramic-based modifier is added into the hydantoin epoxy resin, it can not only be uniformly dispersed in the hydantoin epoxy resin, but also can form a more complex three-dimensional network structure through the crosslinking reaction between the silicon and zirconium elements in the ceramic-based modifier and the hydroxyl and epoxy groups in the hydantoin epoxy resin, thereby effectively improving the thermal stability of the hydantoin epoxy resin, and further improving the thermal stability of the protective layer.

[0110] Test 3:

[0111] The anti-oxidation treated copper foils prepared in Examples 1-3 and the pre-treated copper foil in Comparative Example 4 were placed in an environment with a temperature of 40°C and a humidity of 70% for 72 hours, and the surface was observed for corrosion spot phenomenon. The results are shown in Table 3.

[0112] Test 4:

[0113] The adhesion of the protective layer prepared in Examples 1-3 and Comparative Example 4 was determined by a cross-hatch adhesion tester according to GB / T 9286-1998. The results are shown in Table 3.

[0114] Table 3: Comparison of the anti-oxidation performance of copper foils and the adhesion test results of protective layers of Examples 1-3 and Comparative Example 4

[0115]

[0116] As shown in Table 3, the surface of the pre-treated copper foil in Comparative Example 4 appeared corrosion spots after being placed in an environment with a temperature of 40°C and a humidity of 70% for 72 hours, while the surface of the anti-oxidation treated copper foil prepared in Example 1 did not appear corrosion spots. Therefore, by using alkyl benzimidazole and polyvinyl alcohol as film formers, gallic acid as an antioxidant, triethanolamine as a complexing agent, and an octylphenol polyoxyethylene ether surfactant to prepare an anti-oxidation treatment agent, and then immersing the pre-treated copper foil in the anti-oxidation treatment agent, a stable complex film can be grown on the surface of the copper foil, which can isolate the copper foil from air and prevent the copper foil from being oxidized by air. In addition, the adhesion of the protective layer prepared in Comparative Example 4 to the copper foil was level 2, which was worse than that of Example 1. Therefore, the complex film grown on the surface of the copper foil can react with the functional groups in the protective layer resin, thereby enhancing the bonding force between the resin and the surface of the copper foil and preventing the protective layer from falling off.

[0117] The above examples are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A process for preparing a highly anti-oxidation circuit board, characterized in that: The steps include: S1: Pre-treatment of copper foil The copper foil was immersed in anhydrous ethanol and ultrasonically cleaned for 3-5 minutes. After being taken out, the copper foil was ultrasonically cleaned for 3-5 minutes with deionized water to obtain a pretreated copper foil. S2: Surface antioxidant treatment The pretreated copper foil is immersed in an antioxidant treatment agent, and then placed in a rotary evaporator, with the water bath temperature set at 25-35°C, and rotary evaporated for 20-30 minutes to perform surface coating. After being taken out, it is washed with deionized water and then baked at 100-110°C for 10-20 minutes to obtain an antioxidant treated copper foil; S3: Preparation of composite panels The glass fiber cloth is impregnated in an epoxy resin solution and dried to form a base layer. The base layer is then attached to one side of the anti-oxidation treated copper foil to form a conductive layer. A protective layer resin is then coated on the other side of the anti-oxidation treated copper foil and dried and cured to form a protective layer, thereby obtaining a composite sheet with a "base layer-conductive layer-protective layer" structure. The preparation steps of the protective layer resin are as follows: Dissolve the ceramic-based modifier in N,N-dimethylformamide at a solid-liquid ratio of 1g: (20-30)mL, then add hydantoin epoxy resin, stir and mix for 2-3h, then add zinc oxide composite microspheres, stir and disperse thoroughly to obtain a mixed dispersion; Add tetramethyl bisphenol F cyanate to the above mixed dispersion, heat and stir at 100-120°C for 3-4 hours, and then perform vacuum degassing to obtain a protective layer resin; The preparation steps of zinc oxide composite microspheres are as follows: Add formaldehyde and polyethylene glycol to deionized water at a solid-liquid ratio of (7-8) g:1 g:(500-600) mL, stir and mix thoroughly, then add ammonia water to adjust the pH to 9-10 to obtain a mixed solution; Add green dandelion root polyphenols and zinc sulfate heptahydrate to the mixed solution at a solid-liquid ratio of 1 g: (0.6-0.8) g: (200-300) mL, and stir to mix evenly to obtain a mixed reaction solution; The mixed reaction liquid was transferred to a reactor, heated at 160-180°C for 5-6 hours to carry out a continuous hydrothermal reaction, cooled naturally to room temperature, centrifuged, washed and dried, and then aged at 140-150°C for 1-2 hours to obtain zinc oxide composite microspheres; S4: Preparation of high oxidation resistance circuit boards The composite board is post-processed to obtain a highly anti-oxidation circuit board.

2. The process for preparing a highly anti-oxidation circuit board according to claim 1, characterized in that: The preparation steps of the antioxidant treatment agent are as follows: Add alkylbenzimidazole and polyvinyl alcohol into deionized water and stir thoroughly to dissolve to obtain solution A; Add gallic acid and triethanolamine to the above solution A, continue stirring and fully dissolve to obtain solution B; Octylphenol polyoxyethylene ether was added to the above solution B, mixed thoroughly, and then degassed to obtain an antioxidant treatment agent.

3. The process for preparing a highly anti-oxidation circuit board according to claim 2, wherein: The preparation steps of the ceramic-based modifier are as follows: Add tetraethyl orthosilicate to anhydrous ethanol at a volume ratio of 1:(25-35), stir at room temperature for 3-4 hours to fully dissolve, and obtain a tetraethyl orthosilicate solution; Add diphenylmethane diisocyanate and triethylamine to the above tetraethyl orthosilicate solution, stir for 4-6 hours, then add zirconium orthopropionate, continue stirring for 10-12 hours, and then place in a vacuum drying oven for vacuum drying to obtain a ceramic-based modifier.

4. The process for preparing a highly anti-oxidation circuit board according to claim 2, wherein: The concentrations of the components in the antioxidant treatment agent include: 1-1.5 g / L alkylbenzimidazole, 5.5-6.5 g / L polyvinyl alcohol, 5.8-6.2 g / L gallic acid, 5-6 g / L triethanolamine and 4.5-5.5 g / L octylphenol polyoxyethylene ether.

5. The process for preparing a highly anti-oxidation circuit board according to claim 1, characterized in that: The mass ratio of hydantoin epoxy resin to ceramic-based modifier is (10-12):

1.

6. The process for preparing a highly anti-oxidation circuit board according to claim 1, characterized in that: The mass ratio of zinc oxide composite microspheres to hydantoin epoxy resin is 1:(8-10), and the mass ratio of tetramethyl bisphenol F cyanate to hydantoin epoxy resin is (3-4):

1.

7. The process for preparing a highly anti-oxidation circuit board according to claim 3, characterized in that: The volume ratio of diphenylmethane diisocyanate to tetraethyl orthosilicate solution is 1:(20-30), and the mass ratio of triethylamine to diphenylmethane diisocyanate is 1:(45-50).

8. The process for preparing a highly anti-oxidation circuit board according to claim 3, characterized in that: The mass ratio of zirconium n-propionate to diphenylmethane diisocyanate is (3.4-3.6):1.

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