Anti-static circuit board and production process thereof

Abstract

The invention discloses an anti-static circuit board and a production process thereof, and belongs to the technical field of circuit boards, and the production process comprises the following steps: 1, obtaining polyaniline-based graphene composite powder through amidation and polymerization reaction; step 2, taking AgNO3 as a silver source, loading silver particles on the surface of the Fe3O4 nanowire, and then carrying out surface modification by using a KH-560 silane coupling agent to obtain a modified conductive Fe3O4 nanowire; 3, the polyaniline-based graphene composite powder, the modified conductive Fe3O4 nanowires and other auxiliary materials are subjected to ultrasonic mixing, and anti-static liquid is obtained; 4, etching an inner layer circuit, spraying an anti-static liquid on an outer layer base material, laminating, drilling, performing copper deposition, etching the circuit and performing resistance welding treatment to obtain an anti-static circuit board; according to the anti-static circuit board and the production process thereof, the anti-static performance, the efficient heat conduction performance and the electromagnetic shielding performance are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuit boards, and in particular relates to an anti-static circuit board and a production process thereof. Background Art

[0002] In modern electronic devices, multi-layer circuit boards are particularly sensitive to electrostatic discharge (ESD). These boards typically utilize a multi-layer structure consisting of an epoxy resin / glass fiber substrate and precision copper conductors. Their ESD protection performance directly impacts device reliability.

[0003] Chinese patent application publication number CN117082718A discloses an antistatic multilayer circuit board and its preparation method. The method involves first chlorinating graphene oxide and reacting it with a pyridyl hyperbranched polyamide to produce modified graphene. An acrylic epoxy resin and a silane coupling agent are then polymerized to produce a modified epoxy resin, which is then blended with a conductive filler to produce an antistatic resin. Tin oxide is then deposited on the surface of glass fiber to produce modified glass fiber cloth, which is then composited with the antistatic resin to form a copper-clad laminate substrate. Finally, the antistatic multilayer circuit board is produced through lamination, hot pressing, and circuit processing. The present invention, by modifying the graphene, acrylic epoxy resin, and glass fiber, produces a multilayer circuit board with excellent antistatic properties.

[0004] It is worth noting that static electricity accumulation not only causes transient high voltage to break down sensitive components, causing permanent failure of the devices, but the electrostatic adsorption effect it produces can also lead to dust accumulation, thereby hindering heat conduction and ultimately significantly reducing the reliability of the entire system. Summary of the Invention

[0005] The present invention provides an antistatic circuit board and a production process thereof. A uniformly dispersed PEI-GO dispersion is prepared by a covalent amidation reaction, and ammonium persulfate is used to initiate directional polymerization of aniline monomer on the PEI-GO surface, thereby achieving orderly arrangement of polyaniline molecular chains and improving the conductive stability of the material in a hot and humid environment. Silver particles are loaded on the surface of Fe3O4 nanowires by AgNO3, and then modified with a KH-560 silane coupling agent to prepare modified conductive Fe3O4 nanowires with excellent oxidation resistance. The nanowires not only exhibit enhanced thermal conductivity and wave absorption properties, but the KH-560 modification also ensures stable dispersion in an epoxy resin matrix, thereby achieving a long-lasting antistatic function.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A production process for an anti-static circuit board comprises the following steps: Step 1: The amino groups of PEI undergo covalent amidation reaction with the carboxyl groups on the surface of GO to form a uniform PEI-GO dispersion. In the acidic environment provided by AMPS, ammonium persulfate initiates the directional polymerization of aniline monomer on the surface of PEI-GO to obtain polyaniline-based graphene composite powder; Step 2: Using AgN03 as a silver source, silver particles are loaded on the surface of Fe3O4 nanowires to obtain silver particle-modified conductive nanowires, and then the surface is modified with KH-560 silane coupling agent to obtain modified conductive Fe3O4 nanowires; Step 3: Ultrasonic mixing of polyaniline-based graphene composite powder, modified conductive Fe3O4 nanowires, waterborne epoxy resin RJ-H530, N-methylpyrrolidone and fluorocarbon leveling agent to obtain an antistatic liquid; Step 4: Use a layered spraying process to spray the antistatic liquid on the surface of the outer circuit board substrate, solidify it to obtain an antistatic copper clad laminate, and laminate the inner circuit board with etched circuits, the prepreg and the antistatic copper clad laminate, press them, drill, deposit copper, etch, and solder resist to obtain an antistatic circuit board.

[0007] Furthermore, in step 1, the mass ratio of the polyaniline-based graphene composite powder, the modified conductive Fe3O4 nanowires, the water-based epoxy resin RJ-H530, the N-methylpyrrolidone and the fluorocarbon leveling agent is 2.5-6:3-8:50-80:30-50:1-3.

[0008] Furthermore, the specific preparation method of the polyaniline-based graphene composite powder in step 1 is as follows: GO (graphene oxide) and 1 mol / L acetate buffer were added to a reactor and ultrasonically dispersed to form a uniform GO dispersion. The surface modifier PEI (polyethyleneimine) was then added dropwise at a stirring speed of 500-800 rpm in a water bath at 70-90°C. The mixture was allowed to react for 1-3 hours, washed by centrifugation until neutral, and then ultrasonically dispersed in deionized water to obtain a PEI-GO dispersion. Aniline monomer and the oxidant ammonium persulfate were separately dissolved in 1 mol / L AMPS (2-acrylamido-2-methylpropanesulfonic acid solution). The PEI-GO dispersion was first added to the aniline solution in an ice-water bath and mixed thoroughly. The ammonium persulfate solution was then added dropwise. The mixture was allowed to react for 6-8 hours and then allowed to stand. The product was demulsified with acetone, washed with anhydrous ethanol until neutral, and dried to obtain a polyaniline-based graphene composite powder.

[0009] Furthermore, the dosage ratio of GO, acetate buffer, polyethyleneimine, aniline, ammonium persulfate, AMPS, and PEI-GO dispersion was 0.5-1 g: 0.5-1 L: 0.25-0.5 g: 0.5-1 g: 2-3 g: 0.2-0.4 L: 0.05-0.2 L.

[0010] Furthermore, the modified conductive Fe3O4 nanowires in step 2 are prepared by the following steps: Silver particle-modified Fe3O4 nanowires are dispersed in anhydrous ethanol to form a stable suspension with a concentration of 0.1-20 mg / mL. Hydroxyl active sites are exposed on the surface of the nanowires. A KH-560 silane coupling agent is added at a volume ratio of 1:100-0.05 to the suspension for reaction. The reaction is carried out at a stirring speed of 200-500 rpm and a water bath heating condition of 70-90°C for 6-8 hours. After the reaction is completed, the product is centrifuged, filtered, washed, and dried to obtain modified conductive Fe3O4 nanowires.

[0011] Furthermore, silver particle-modified Fe3O4 nanowires were prepared by the following steps: The reducing agent glucose, the dispersant polyvinyl pyrrolidone and the deionized water were mixed evenly, and the pH value was adjusted to 11 with NaOH to prepare liquid A. AgNO3, Fe3O4 nanowires and deionized water were mixed evenly to prepare liquid B. Liquid A and liquid B were mixed in a volume ratio of 1:1 and added to a reactor, reacted at 70-80°C for 30-60 minutes, and the resulting product was centrifuged, filtered, washed and dried to obtain Fe3O4 nanowires modified with silver particles.

[0012] Furthermore, the dosage ratio of glucose, polyvinyl pyrrolidone and deionized water in solution A is 1-1.5 g: 0.3-0.5 g: 20-30 mL; the dosage ratio of AgNO3, Fe3O4 nanowires and deionized water in solution B is 0.4-0.6 g: 0.1-0.3 g: 10-30 mL.

[0013] Furthermore, Fe3O4 nanowires are prepared by the following steps: Iron source FeSO4·7H2O, sulfur source Na2S2O3·5H2O and polyethylene glycol aqueous solution (the volume ratio of polyethylene glycol to deionized water is 1:3) are added to a reactor and stirred until FeSO4·7H2O and Na2S2O3·5H2O are dissolved. NaOH is added to adjust the pH value to 11, and the temperature is raised to 140-160°C at 5°C / min. The reaction is carried out for 28-42 hours, and the mixture is naturally cooled to room temperature. The product is centrifuged, filtered, washed, and freeze-dried to obtain Fe3O4 nanowires.

[0014] Furthermore, the usage ratio of FeSO4·7H2O, Na2S2O3·5H2O and polyethylene glycol aqueous solution is 1-2 g:0.5-1.5 g:10-30 mL.

[0015] Furthermore, the specific method of the layered spraying process in step 4 is as follows: First apply a thin layer of 5-8μm antistatic liquid on the surface of the outer circuit board substrate, let it stand at 25℃ for 3-5 minutes, and then apply antistatic liquid after leveling. The total thickness should be controlled at 12-15μm.

[0016] Beneficial effects of the present invention: 1. The PEI molecular chains of the present invention are grafted onto the GO surface through an amidation reaction to form a PEI-GO composite structure. The steric hindrance effect inhibits the aggregation of graphene sheets. The amino and imino groups on PEI impart polarity, which facilitates dispersion in the polar system of water-based epoxy resin and NMP. At the same time, during the polymerization process, the sulfonic acid group of AMPS promotes the dissolution of aniline, guiding the directional growth of polyaniline along the PEI-GO surface and preventing molecular aggregation.

[0017] 2. The present invention uses a glucose reduction method to achieve uniform loading of silver particles on the surface of Fe3O4 nanowires. The low-resistance silver particles construct an efficient static conductive channel, providing a path for rapid discharge of static charge, significantly improving the conductivity of the material. At the same time, the high thermal conductivity of the silver particles themselves can also effectively assist in heat dissipation.

[0018] 3. The one-dimensional linear structure of the Fe3O4 nanowires in the present invention can extend the scattering path of electromagnetic waves and enhance energy dissipation efficiency. In addition, the silver particles are uniformly loaded on its surface to form a continuous conductive network, which effectively dissipates electromagnetic energy through the conductivity loss mechanism, synergistically improving the absorption capacity of electromagnetic waves.

[0019] 4. The surface of PEI-modified GO has amino groups, which bind to the hydroxyl and epoxy groups on the surface of the modified conductive Fe3O nanowires through hydrogen bonds, effectively enhancing the interfacial compatibility; at the same time, when the composite powder is dispersed in an antistatic liquid, the sulfonic acid group dissociates in the polar medium to produce negatively charged SO3 - , modified OH on the surface of Fe3O4 nanowires - Partially dissociated in an aqueous system, it also forms a negatively charged surface. The repulsion of like charges inhibits aggregation and achieves stable dispersion. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1: This embodiment provides an anti-static circuit board, comprising the following steps: S1: 5g GO and 5L 1mol / L acetate buffer were added to a reactor and ultrasonically dispersed to form a uniform GO dispersion. 2.5g polyethyleneimine was added dropwise at 600rpm and 70℃ in a water bath. The mixture was reacted for 2h, washed by centrifugation until neutral, and then ultrasonically dispersed in deionized water to obtain a PEI-GO dispersion. 7g aniline and 23g ammonium persulfate were dissolved in 2L 1mol / L 2-acrylamido-2-methylpropanesulfonic acid solution (AMPS) respectively. In an ice-water bath, 1L of the PEI-GO dispersion was first added to the aniline solution and mixed. Then, the ammonium persulfate solution was added dropwise. The mixture was reacted for 6h and allowed to stand for 24h. The product was demulsified with acetone, washed with anhydrous ethanol until neutral, and dried to obtain a polyaniline-based graphene composite powder.

[0022] The oxygen-containing functional groups on the GO surface react with the amino groups of polyethyleneimine through covalent amidation to form PEI-GO. Under acidic conditions, the oxidant oxidizes aniline to initiate a polymerization reaction to form polyaniline.

[0023] S2: Add 10 g of FeSO4·7H2O, 5 g of Na2S2O3·5H2O and 100 mL of polyethylene glycol aqueous solution (the volume ratio of polyethylene glycol to deionized water is 1:3) into the reactor and stir until FeSO4·7H2O and Na2S2O3·5H2O are dissolved. Then add NaOH to adjust the pH to 11, heat to 140°C at 5°C / min, react for 28 h, and naturally cool to room temperature. The product is centrifuged and filtered, washed three times with anhydrous ethanol, and freeze-dried to obtain Fe3O4 nanowires.

[0024] S3: 15 g glucose, 5 g polyvinyl pyrrolidone, and 300 mL deionized water were added to a reactor, and the pH value was adjusted to 11 with NaOH to prepare liquid A. 6 g AgNO3, 3 g Fe3O4 nanowires, and 100 mL deionized water were added to the reactor to prepare liquid B. Liquid A and liquid B were mixed in a volume ratio of 1:1 and added to the reactor. The mixture was reacted at 70°C for 30 min. The resulting precipitate was washed three times with deionized water and anhydrous ethanol, respectively, and dried to obtain silver particle-modified Fe3O4 nanowires.

[0025] S4: 1 g of silver particle-modified Fe3O4 nanowires was dispersed in 100 mL of anhydrous ethanol to form a stable suspension. Hydroxyl active sites were exposed on the surface of the nanowires. 5 mL of KH-560 silane coupling agent was added for condensation reaction. The reaction was heated in a water bath at 200 rpm and 80°C for 6 h. The product was centrifuged and filtered, washed three times with anhydrous ethanol, and dried to obtain modified conductive Fe3O4 nanowires.

[0026] S5: 2.5 g of polyaniline-based graphene composite powder, 5 g of modified conductive Fe3O4 nanowires, 60 g of waterborne epoxy resin RJ-H530, 45 g of N-methylpyrrolidone and 2 g of fluorocarbon leveling agent were ultrasonically mixed to obtain an antistatic liquid.

[0027] S6: Use acetone and ethanol to ultrasonically clean the circuit board substrate, and then use the layered spraying process to spray the anti-static liquid. First apply a thin layer of 6μm, let it stand at 25℃ for 3 minutes to level it, and then apply it again. The total thickness is controlled at 12μm. It is cured at 70℃ for 30 minutes to form an anti-static copper clad laminate.

[0028] S7: After the inner layer circuit board with etched circuits, prepreg and antistatic copper clad laminate are stacked, pressed, drilled, copper deposited, etched and solder resisted to obtain an antistatic circuit board.

[0029] Embodiment 2: This embodiment provides an anti-static circuit board, comprising the following steps: S1: 6g GO and 6L 1mol / L acetate buffer were added to a reactor and ultrasonically dispersed to form a uniform GO dispersion. 3g polyethyleneimine was added dropwise at 600rpm and 80℃ in a water bath. The mixture was reacted for 1h, washed by centrifugation until neutral, and then ultrasonically dispersed in deionized water to obtain a PEI-GO dispersion. 8g aniline and 25g ammonium persulfate were dissolved in 3L 1mol / L 2-acrylamido-2-methylpropanesulfonic acid solution (AMPS) respectively. In an ice-water bath, 1.5L of the PEI-GO dispersion was first added to the aniline solution and mixed thoroughly. Then, the ammonium persulfate solution was added dropwise. The mixture was reacted for 7h and allowed to stand for 36h. The product was demulsified with acetone, washed with anhydrous ethanol until neutral, and dried to obtain a polyaniline-based graphene composite powder.

[0030] S2: Add 15g FeSO4·7H2O, 10g Na2S2O3·5H2O and 200mL polyethylene glycol aqueous solution (the volume ratio of polyethylene glycol to deionized water is 1:3) into the reactor and stir until FeSO4·7H2O and Na2S2O3·5H2O are dissolved. Then add NaOH to adjust the pH to 11, heat to 150℃ at 5℃ / min, react for 28h, and cool naturally to room temperature. The product is centrifuged and filtered, washed three times with anhydrous ethanol, and freeze-dried to obtain Fe3O4 nanowires.

[0031] S3: 10 g glucose, 3 g polyvinyl pyrrolidone, and 200 mL deionized water were added to a reactor, and the pH value was adjusted to 11 with NaOH to prepare liquid A. 4 g AgNO3, 1 g Fe3O4 nanowires, and 100 mL deionized water were added to the reactor to prepare liquid B. Liquid A and liquid B were mixed in a volume ratio of 1:1 and added to the reactor. The mixture was reacted at 75°C for 45 min. The resulting precipitate was washed three times with deionized water and anhydrous ethanol, respectively, and dried to obtain silver particle-modified Fe3O4 nanowires.

[0032] S4: 1 g of silver particle-modified Fe3O4 nanowires was dispersed in 500 mL of anhydrous ethanol to form a stable suspension. Hydroxyl active sites were exposed on the surface of the nanowires. 12 mL of KH-560 silane coupling agent was added for condensation reaction. The reaction was heated in a water bath at 200 rpm and 80°C for 7 h. The product was centrifuged and filtered, washed three times with anhydrous ethanol, and dried to obtain modified conductive Fe3O4 nanowires.

[0033] S5: 4 g of polyaniline-based graphene composite powder, 3 g of modified conductive Fe3O4 nanowires, 50 g of waterborne epoxy resin RJ-H530, 30 g of N-methylpyrrolidone and 1 g of fluorocarbon leveling agent were ultrasonically mixed to obtain an antistatic liquid.

[0034] S6: Use acetone and ethanol to ultrasonically clean the circuit board substrate, and then use the layered spraying process to spray the anti-static liquid. First apply a thin layer of 7μm, let it stand at 25℃ for 4 minutes to level it, and then apply it again. The total thickness is controlled at 13μm. It is cured at 50℃ for 40 minutes to form an anti-static copper clad laminate.

[0035] S7: After the inner layer circuit board with etched circuits, prepreg and antistatic copper clad laminate are stacked, pressed, drilled, copper deposited, etched and solder resisted to obtain an antistatic circuit board.

[0036] Embodiment 3: This embodiment provides an anti-static circuit board, comprising the following steps: S1: 10g GO and 10L 1mol / L acetate buffer were added to a reactor and ultrasonically dispersed to form a uniform GO dispersion. 5g polyethyleneimine was added dropwise at 600rpm and 90℃ in a water bath. The mixture was reacted for 3h, washed by centrifugation until neutral, and then ultrasonically dispersed in deionized water to obtain a PEI-GO dispersion. 10g aniline and 30g ammonium persulfate were dissolved in 4L 1mol / L 2-acrylamido-2-methylpropanesulfonic acid solution (AMPS) respectively. In an ice-water bath, 2.5L of the PEI-GO dispersion was first added to the aniline solution and mixed thoroughly. Then, the ammonium persulfate solution was added dropwise. The mixture was reacted for 8h and allowed to stand for 42h. The product was demulsified with acetone, washed with anhydrous ethanol until neutral, and dried to obtain a polyaniline-based graphene composite powder.

[0037] S2: Add 20 g of FeSO4·7H2O, 15 g of Na2S2O3·5H2O and 300 mL of polyethylene glycol aqueous solution (the volume ratio of polyethylene glycol to deionized water is 1:3) into the reactor and stir until the FeSO4·7H2O and Na2S2O3·5H2O are dissolved. Then, add NaOH to adjust the pH to 11. The temperature is raised to 160°C at 5°C / min, and the reaction is carried out for 28 h. The reaction is then naturally cooled to room temperature. The product is centrifuged and filtered, washed three times with anhydrous ethanol, and freeze-dried to obtain Fe3O4 nanowires.

[0038] S3: 12 g of glucose, 4 g of polyvinylpyrrolidone, and 250 mL of deionized water were added to a reactor, and the pH value was adjusted to 11 with NaOH to prepare liquid A. 5 g of AgNO3, 1.6 g of Fe3O4 nanowires, and 100 mL of deionized water were added to the reactor to prepare liquid B. Liquid A and liquid B were mixed in a volume ratio of 1:1 and added to the reactor. The mixture was reacted at 80°C for 60 min. The resulting precipitate was washed three times with deionized water and anhydrous ethanol, respectively, and dried to obtain silver particle-modified Fe3O4 nanowires.

[0039] S4: 1 g of silver particle-modified Fe3O4 nanowires was dispersed in 1000 mL of anhydrous ethanol to form a stable suspension. Hydroxyl active sites were exposed on the surface of the nanowires. 10 mL of KH-560 silane coupling agent was added for condensation reaction. The reaction was carried out at a stirring speed of 200 rpm and heating in an 80°C water bath for 8 h. The product was centrifuged and filtered, washed three times with anhydrous ethanol, and dried to obtain modified conductive Fe3O4 nanowires.

[0040] S5: 6 g of polyaniline-based graphene composite powder, 8 g of modified conductive Fe3O4 nanowires, 80 g of waterborne epoxy resin RJ-H530, 50 g of N-methylpyrrolidone and 3 g of fluorocarbon leveling agent were ultrasonically mixed to obtain an antistatic liquid.

[0041] S6: Use acetone and ethanol to ultrasonically clean the circuit board substrate, and then use the layered spraying process to spray the anti-static liquid. First apply a thin layer of 8μm, let it stand at 25℃ for 5 minutes to level it, and then apply it again. The total thickness is controlled at 15μm. It is cured at 60℃ for 50 minutes to form an anti-static copper clad laminate.

[0042] S7: After the inner layer circuit board with etched circuits, prepreg and antistatic copper clad laminate are stacked, pressed, drilled, copper deposited, etched and solder resisted to obtain an antistatic circuit board.

[0043] The SY-1080 prepreg was used in the examples, and the other raw materials were all commercially available products. Lamination, drilling, copper plating, etching, and solder resist were all performed using existing technologies, and the drilling, copper plating, etching, and solder resist process conditions were the same in Examples 1 to 3.

[0044] Comparative Example 1: The difference from Example 1 is that step S3 is omitted, and the Fe3O4 nanowires in step S2 are directly treated in the manner of step S4 to prepare modified Fe3O4 nanowires, and the modified conductive Fe3O4 nanowires in step S5 are replaced to prepare an antistatic liquid. The other steps remain unchanged to obtain an antistatic circuit board.

[0045] Comparative Example 2: The difference from Example 1 is that step S4 is omitted, and the modified conductive Fe3O4 nanowires in step S5 are replaced by the silver particle-modified Fe3O4 nanowires prepared in step S3 to prepare an antistatic liquid. The other steps remain unchanged to obtain an antistatic circuit board.

[0046] Comparative Example 3: The difference from Example 1 is that the synthesis of Fe3O4 nanowires in step S2 is omitted, and commercial Fe3O4 particles are used instead to prepare modified conductive Fe3O4 nanoparticles, and the modified conductive Fe3O4 nanowires in step S5 are replaced to prepare an antistatic liquid. The other steps remain unchanged to obtain an antistatic circuit board.

[0047] Performance Testing: The antistatic circuit boards of Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests: surface resistance was measured according to GB / T 1410-2006; thermal conductivity was tested according to ASTM D 5470; and absorption and reflectivity were measured using a bow reflection test system and an Agilent N5224A vector network analyzer in the 2-18 GHz frequency range and at 25±1°C, using the national military standard GJB 2038-94. The antistatic liquids were placed in separate transparent glass bottles, sealed, and allowed to stand for one week. The state of the antistatic liquids was then observed to evaluate their dispersion stability. The results are shown in Table 1.

[0048] Table 1 Performance test results of various anti-static circuit boards As can be seen from Table 1, the surface resistance of Examples 1 to 3 is stable at 10 5 Ω, significantly better than 10 of Comparative Examples 1-3 6 -10 7 Ω, indicating that the antistatic performance of Examples 1 to 3 is more significant. Comparative Example 1 did not undergo silver particle modification and relied solely on Fe3O4 nanowires, resulting in a decrease in electron transfer efficiency and an increase in surface resistance to 10 6 Ω, in Comparative Example 2, the nanowires agglomerated, the conductive path was discontinuous, and the resistance increased because the silane coupling agent modification was not performed. In Comparative Example 3, commercial Fe3O4 particles were used instead of synthetic nanowires. The granular morphology made it difficult to form a long-range continuous conductive network, further deteriorating the conductive performance.

[0049] The thermal conductivity of Examples 1 to 3 (24-31 W / m·K) is better than that of Comparative Examples 1-3 (19-22 W / m·K). Since Comparative Example 1 is not modified with silver particles, the material system lacks a silver metal phase with high thermal conductivity. Since Comparative Example 2 is not modified with a silane coupling agent, the nanowires are unevenly dispersed, resulting in significant interfacial thermal resistance. Comparative Example 3 uses commercial Fe3O4 particles instead of one-dimensional nanowires, and its smaller contact area and larger interfacial thermal resistance further reduce the thermal conductivity efficiency.

[0050] Example 1 exhibits excellent electromagnetic wave absorption performance, with a minimum reflection loss of -30.5 dB, which is significantly better than -25.5 dB in Comparative Example 3. This difference is mainly due to the fact that Comparative Example 3 uses commercial Fe3O4 particles instead of nanowires, resulting in the material being unable to construct an effective electromagnetic wave transmission channel, thereby significantly reducing the absorption performance.

[0051] The antistatic liquids of Example 1 and Comparative Example 1 remained stable without precipitation after standing for one week, while Comparative Examples 2 and 3 showed obvious stratification. Since Comparative Example 2 was not modified by silane coupling, the nanowires agglomerated and settled, eventually forming obvious precipitation. Although Comparative Example 3 was surface treated, the commercial Fe3O4 particles had irregular morphology and high surface roughness, which increased the contact area and friction resistance between the particles.

[0052] It should be noted that, in this document, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0053] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A production process for an anti-static circuit board, the production process comprising: The inner layer circuit board with etched circuits, the prepreg and the antistatic copper clad laminate are laminated, pressed, drilled, copper deposited, etched and solder resisted. The antistatic copper clad laminate is prepared by the following steps: Step 1: The amino groups of PEI undergo covalent amidation reaction with the carboxyl groups on the surface of GO to form a uniform PEI-GO dispersion. In the acidic environment provided by AMPS, ammonium persulfate initiates the directional polymerization of aniline monomer on the surface of PEI-GO to obtain polyaniline-based graphene composite powder; Step 2: Using AgN03 as a silver source, silver particles are loaded on the surface of Fe3O4 nanowires to obtain silver particle-modified conductive nanowires, and then the surface is modified with KH-560 silane coupling agent to obtain modified conductive Fe3O4 nanowires; Step 3: Ultrasonic mixing of polyaniline-based graphene composite powder, modified conductive Fe3O4 nanowires, waterborne epoxy resin RJ-H530, N-methylpyrrolidone and fluorocarbon leveling agent to obtain an antistatic liquid; Step 4: Use a layered spraying process to spray the antistatic liquid on the surface of the outer circuit board substrate and solidify it to obtain an antistatic copper clad laminate.

2. The production process of an anti-static circuit board according to claim 1, characterized in that: The mass ratio of the polyaniline-based graphene composite powder, modified conductive Fe3O4 nanowires, water-based epoxy resin RJ-H530, N-methylpyrrolidone and fluorocarbon leveling agent is 2.5-6:3-8:50-80:30-50:1-3.

3. The production process of an anti-static circuit board according to claim 2, characterized in that: The specific preparation method of the polyaniline-based graphene composite powder is as follows: GO and 1 mol / L acetate buffer were added to a reactor and ultrasonically dispersed to form a GO dispersion. PEI was added dropwise at 500-800 rpm and 70-90°C in a water bath, reacted for 1-3 hours, centrifuged and washed until neutral, and then ultrasonically dispersed in deionized water to obtain a PEI-GO dispersion. Aniline and ammonium persulfate were respectively dissolved in 1 mol / L AMPS. In an ice-water bath, the PEI-GO dispersion was first added to the aniline solution and mixed, and then the ammonium persulfate solution was added dropwise. The mixture was reacted for 6-8 hours and allowed to stand. The product was demulsified with acetone, washed with anhydrous ethanol until neutral, and dried to obtain a polyaniline-based graphene composite powder.

4. The production process of an anti-static circuit board according to claim 3, characterized in that: The dosage ratio of the GO, acetate buffer, polyethyleneimine, aniline, ammonium persulfate, AMPS and PEI-GO dispersion is 0.5-1 g: 0.5-1 L: 0.25-0.5 g: 0.5-1 g: 2-3 g: 0.2-0.4 L: 0.05-0.2 L.

5. The production process of an anti-static circuit board according to claim 2, characterized in that: The specific preparation method of the modified conductive Fe3O4 nanowires is as follows: Silver particle-modified Fe3O4 nanowires were dispersed in anhydrous ethanol to form a suspension with a concentration of 0.1-20 mg / mL, and a KH-560 silane coupling agent was added at a volume ratio of 1:100-0.05 to the suspension for reaction at 200-500 rpm and 70-90°C in a water bath for 6-8 hours. The product was centrifuged, filtered, washed, and dried to obtain modified conductive Fe3O4 nanowires.

6. The production process of an anti-static circuit board according to claim 5, characterized in that: The specific preparation method of the silver particle modified Fe3O4 nanowires is as follows: Glucose, polyvinyl pyrrolidone and deionized water were mixed and the pH value was adjusted to 11 with NaOH to prepare liquid A. AgNO3, Fe3O4 nanowires and deionized water were mixed to prepare liquid B. Liquid A and liquid B were mixed in a volume ratio of 1:1 and added to a reactor. The mixture was reacted at 70-80°C for 30-60 minutes. The product was centrifuged, filtered, washed and dried to obtain Fe3O4 nanowires modified with silver particles.

7. The production process of an anti-static circuit board according to claim 6, characterized in that: The dosage ratio of glucose, polyvinyl pyrrolidone and deionized water in the solution A is 1-1.5 g: 0.3-0.5 g: 20-30 mL; the dosage ratio of AgNO3, Fe3O4 nanowires and deionized water in the solution B is 0.4-0.6 g: 0.1-0.3 g: 10-30 mL.

8. The production process of an anti-static circuit board according to claim 6, characterized in that: The specific preparation method of Fe3O4 nanowires is as follows: FeSO4·7H2O, Na2S2O3·5H2O and polyethylene glycol aqueous solution (the volume ratio of polyethylene glycol to deionized water is 1:3) are added to a reactor, and NaOH is added to adjust the pH value to 11. The temperature is raised to 140-160°C at 5°C / min and the reaction is carried out for 28-42 hours. The product is centrifuged, filtered, washed, and freeze-dried to obtain Fe3O4 nanowires. The usage ratio of the FeSO4·7H2O, Na2S2O3·5H2O and polyethylene glycol aqueous solution is 1-2g:0.5-1.5g:10-30mL.

9. The production process of an anti-static circuit board according to claim 1, characterized in that: The specific method of the layered spraying process is as follows: First apply a thin layer of 5-8μm antistatic liquid on the surface of the outer circuit board substrate, let it stand at 25℃ for 3-5 minutes, and then apply antistatic liquid after leveling. The total thickness should be controlled at 12-15μm.

10. An anti-static circuit board, characterized in that: It is prepared by the production process described in any one of claims 1 to 9.

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