FPC (Flexible Printed Circuit) inorganic liquid medicine and preparation process

Abstract

The invention relates to the technical field of high-temperature resistant coatings, and discloses an FPC (Flexible Printed Circuit) inorganic liquid medicine, which is prepared from the following components in parts by mass: 2 to 5 parts of sodium phosphomolybdate; 1-3 parts of hexafluorozirconic acid; 0.5 to 2 parts of a silane coupling agent, wherein the silane coupling agent is selected from gamma-aminopropyl triethoxy silane or gamma-methacryloyloxypropyl trimethoxy silane; 0.5-1 part of zinc chloride; 1-3 parts of a complexing agent; 0.1-0.3 part of nano-silver particles, wherein the particle size of the nano-silver particles is The total mass part of the components is 100 parts. By optimizing the formula of the coating, the high-temperature resistance and the oxidation resistance are improved, the coating is kept stable in a high-temperature environment, the thermal decomposition rate is reduced, the service life is prolonged, the mechanical strength of a film layer is enhanced through reasonable cross-linked molecules, and the problems of high-temperature cracks and falling off are effectively prevented. In addition, the oxidation rate of the coating is optimized, generation of copper oxide at high temperature is reduced, and the protection effect of a metal matrix is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature tolerance coatings, and specifically to an FPC inorganic potion and its preparation process. Background Art

[0002] The oxidation problem of metal materials in high-temperature environments has always been an important research direction in the engineering field. Especially in high-temperature application scenarios such as aviation, electronics, and industrial equipment, the high-temperature resistance performance of coatings directly affects the stability and lifespan of equipment. In order to enhance the thermal oxidation resistance of the metal surface, functional protective coatings are often used to reduce the erosion of the high-temperature environment on the metal substrate. However, with the continuous expansion of application scenarios, the requirements for the temperature resistance performance of coatings are also getting higher and higher.

[0003] Currently, the high-temperature resistant coatings on the market mainly rely on inorganic ceramic coatings or organosilicon-based resin coatings. Inorganic ceramic coatings exhibit good stability at high temperatures, but they are often brittle and difficult to adapt to the thermal expansion changes of the metal substrate, resulting in cracks or peeling during high-temperature use. The organosilicon-based coatings, although having good flexibility, have a limited temperature resistance limit and are prone to decomposition above 400 °C, leading to the failure of coating protection. In addition, although some coating technologies enhanced by nano metal particles have improved antioxidant performance, the agglomeration problem of nano particles still exists in high-temperature environments, limiting the uniformity and long-term stability of the coatings.

[0004] The existing technologies still have deficiencies in high-temperature tolerance. Especially during long-term high-temperature use of coatings, they are prone to thermal cracking and oxidation failure, resulting in a decline in the coating protection performance. This problem affects the application stability of coatings in high-temperature industrial environments. Therefore, developing a coating technology with both high-temperature stability and antioxidant ability has become an urgent technical problem to be solved. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technologies, the present invention provides an FPC inorganic potion and its preparation process, which solves the problem of easy thermal cracking and oxidation failure of coatings during long-term high-temperature use.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: An FPC inorganic potion, comprising components in the following mass fractions: 2 - 5 parts of sodium phosphomolybdate; 1 - 3 parts of zirconium fluoroacid; 0.5 - 2 parts of silane coupling agent, where the silane coupling agent is selected from γ-aminopropyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane; 0.5 - 1 part of zinc chloride; 1 - 3 parts of complexing agent, where the complexing agent is trisodium citrate; 0.1 - 0.3 part of nano silver particles with a particle size of 10 - 50 nm and surface-modified with carboxyl functional groups; 0.2 - 0.5 part of anionic surfactant; Add deionized water in excess to make the total mass fraction of each component 100 parts; Among them, the mass ratio of sodium phosphomolybdate to zirconium fluoride is 2:1 to 5:3.

[0007] Preferably, the sodium phosphomolybdate is hydrated sodium phosphomolybdate.

[0008] Preferably, the concentration of zirconium fluoride is 0.1 - 0.5 mol / L.

[0009] Preferably, the surface carboxyl functional groups of the silver nanoparticles are modified by the sodium citrate reduction method.

[0010] Preferably, the anionic surfactant is sodium dodecyl sulfate or sodium dodecylbenzenesulfonate.

[0011] An FPC inorganic chemical solution preparation process includes the following steps: S1. Dissolve sodium phosphomolybdate, zirconium fluoride, and zinc chloride in deionized water, magnetically stir for 30 - 60 min until completely dissolved, and add 0.1 - 0.5 mol / L dilute nitric acid to adjust the pH to 4.5 - 5.5; S2. Add trisodium citrate to the solution in step S1, stir for 10 - 20 min, and control the temperature at 25 - 35 °C; S3. Add γ-aminopropyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane, continue to stir for 10 - 30 min, and maintain the pH at 4.5 - 5.5; S4. Add an anionic surfactant, stir for 30 - 60 min, and control the solution temperature at 25 - 35 °C; S5. Under nitrogen protection, add silver nanoparticles with surface-modified carboxyl functional groups to the mixed solution, perform ultrasonic dispersion treatment for 5 - 15 min, the ultrasonic frequency is 20 - 40 kHz, and the power density is 50 - 100 W / cm 2 , and control the temperature at 20 - 30 °C; S6: Perform vacuum degassing treatment on the solution, the vacuum degree is -0.08 to -0.1 MPa, then filter with a 0.2 - 0.45 μm microporous filter membrane, fill with nitrogen until the oxygen content in the container ≤ 1%, and store it sealed in a light-proof container made of brown glass or polypropylene, and the storage temperature is 5 - 25 °C Preferably, the rotation speed of the magnetic stirring in step S1 is 500 - 800 rpm.

[0012] Preferably, the power density of the ultrasonic dispersion in step S5 is 70 - 90 W / cm 2 .

[0013] Preferably, the duration of the vacuum degassing treatment in step S6 is 5 - 10 min.

[0014] Preferably, the light-shielding container is made of polypropylene, and the inner wall is coated with an anti-oxidation film layer.

[0015] The present invention provides an FPC inorganic potion and a preparation process. It has the following beneficial effects: 1. The present invention adopts the technology of finely controlling the dispersion of silver nanoparticles in the coating formulation, achieving the technical effect of maintaining good structural stability at high temperatures. Compared with the traditional formulations used in the prior art, it solves the deficiency that the coating is prone to oxidation and deterioration at high temperatures, and extends the service life of the product.

[0016] 2. The potion formulation of the present invention optimizes the molecular structure of high-temperature tolerance. Through reasonable cross-linked molecular design, the coating is not prone to cracks and peeling in a high-temperature environment, solving the problems of thermal cracks and peeling that easily occur in the coating in traditional technologies, and improving the mechanical stability of the coating.

[0017] 3. The present invention adds an efficient heat stabilizer to the coating, significantly reducing the pyrolysis rate of the film layer at extremely high temperatures, achieving the technical effect of reducing the rates of thermal decomposition and oxidation reactions. Compared with the formulations without enhanced design in the prior art, it solves the problems of poor high-temperature resistance and insufficient antioxidant capacity of the coating.

[0018] 4. The present invention adopts a multi-component formulation, controls the oxidation rate of the coating, and shows a lower proportion of copper oxide formation in a high-temperature environment. Compared with the formulations with too fast oxidation reactions in traditional technologies, it solves the problem of increased oxidation of the coating at high temperatures, providing a more reliable coating solution for high-temperature applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Please refer to the attached Figure 1 , the embodiments of the present invention provide an FPC inorganic potion and a preparation process, aiming to improve the corrosion resistance and conductivity of the copper surface by forming a stable protective film, and at the same time improve the welding reliability. Specifically, it includes: Sodium phosphomolybdate (NaPMo 12 O 40) 2 - 5 parts, sodium phosphomolybdate is a strong oxidizing polyacid salt, which can react with copper ions (Cu 2+ ) on the copper surface to form a copper phosphomolybdate protective film (NaPMo 12 O 40 ). This protective film has good corrosion resistance and can effectively inhibit the oxidation of the copper surface. At the same time, the presence of phosphomolybdate can improve the hydrophilicity of the copper surface, making the subsequent coating easier to adhere.

[0022] 1 - 3 parts of fluozirconic acid (H2ZrF6), fluozirconic acid is an inorganic fluoride, which can undergo hydrolysis reaction on the copper surface to form a nano - zirconia (ZrO2) protective layer: H2ZrF6 + H2O → ZrO2 + 6HF This layer has a dense structure, high chemical stability and mechanical strength, which can further enhance the antioxidant ability of copper and improve the resistance to welding thermal shock performance. In addition, the ZrO2 layer can also play a physical barrier role, reducing the possibility of electrochemical corrosion on the copper surface.

[0023] 0.5 - 2 parts of silane coupling agent (SiO3 2- ), γ - aminopropyltriethoxysilane (KH - 550) or γ - methacryloxypropyltrimethoxysilane (KH - 570) is selected. This type of silane coupling agent can undergo hydrolysis and condensation on the copper surface to form Si - O - Cu covalent bonds, enhancing the adhesion of the inorganic protective layer. At the same time, the silane coupling agent can also improve the dispersion of nano - silver particles, making them evenly distributed in the protective film.

[0024] 0.5 - 1 part of zinc chloride (ZnCl2), zinc chloride is a weak complexing agent, which can promote the densification of the protective film by providing Zn 2+ ions. At the same time, Zn 2+ can act synergistically with sodium phosphomolybdate to improve the corrosion resistance of the copper surface. In addition, Zn 2+ can adjust the oxidation - reduction potential of the copper surface and reduce the occurrence of self - corrosion phenomenon.

[0025] 1 - 3 parts of complexing agent (trisodium citrate), trisodium citrate is a commonly used metal ion complexing agent, which can effectively control the coordination state of metal ions such as Cu 2+ , Zr 4+ , Zn 2+ etc., prevent precipitation formation, and improve the stability of the solution. In addition, citrate can also participate in the surface modification of silver nanoparticles, improve their dispersion, and enhance the antioxidant ability.

[0026] 0.1 - 0.3 parts of silver nanoparticles (AgNPs), with a particle size of 10 - 50 nm. The surface of the silver nanoparticles is modified with carboxyl functional groups (-COOH), which can bind to copper phosphomolybdate and ZrO2 film through electrostatic interaction, enabling the silver particles to be uniformly dispersed in the protective layer. The silver particles themselves have excellent electrical conductivity, which can provide low-resistance contact during the welding process. At the same time, their antibacterial property can inhibit surface organic contamination and improve the long-term reliability of the PCB.

[0027] An anionic surfactant (0.2 - 0.5 parts), selected from sodium dodecyl sulfate (SDS) or sodium dodecylbenzenesulfonate (SDBS), whose main functions are: Promote the stable dispersion of silver nanoparticles and prevent aggregation; Improve the wettability of the potion on the copper surface and enable the protective film to be deposited uniformly.

[0028] Deionized water (the balance); As a solvent, it ensures the uniform distribution of the potion components and avoids the influence of ionic impurities in the solution on the formation quality of the protective film.

[0029] The preparation of the inorganic potion adopts the following steps to ensure the full dissolution and uniform dispersion of each component and to ensure the long-term stability of the potion: S1: Dissolve the main salts and adjust the pH Dissolve sodium phosphomolybdate, zirconium fluoride, and zinc chloride in deionized water in sequence, and stir magnetically for 30 - 60 min until completely dissolved. At the same time, adjust the pH to 4.5 - 5.5 with 0.1 - 0.5 mol / L dilute nitric acid.

[0030] Control the pH range to ensure that sodium phosphomolybdate and zirconium fluoride do not undergo excessive hydrolysis or precipitation; A low pH environment helps to form a denser copper phosphomolybdate and ZrO2 layer and improve the corrosion resistance of the protective film.

[0031] S2: Complex metal ions Add trisodium citrate and stir for 10 - 20 min, controlling the temperature at 25 - 35 °C to stabilize the complex state of the metal ions.

[0032] The complexing agent can prevent the premature precipitation of metal ions and ensure the uniform formation of the protective film; Improve the storage stability of the potion and prevent the precipitation of components after long-term storage.

[0033] S3: Add a silane coupling agent Continue to stir for 10 - 30 min, maintaining the pH at 4.5 - 5.5 to hydrolyze the silane and form chemical bonds with the copper surface.

[0034] The hydrolysis of silane molecules forms a -Si-OH structure, which undergoes a condensation reaction with the -OH groups on the copper surface to form a strong Si-O-Cu bond; Enhance the bonding strength of the inorganic protective layer and improve wear and corrosion resistance.

[0035] S4: Add a surfactant Stir for 30 - 60 min, and control the solution temperature at 25 - 35 °C to stabilize the dispersion state of the silver nanoparticles.

[0036] The surfactant reduces the surface tension of the silver particles and prevents particle agglomeration; Enhance the wetting ability of the potion on the copper surface and make the protective layer more uniform.

[0037] S5: Ultrasonic dispersion of silver nanoparticles Under nitrogen protection, add silver nanoparticles modified with carboxyl functional groups to the mixed solution, and perform ultrasonic dispersion treatment for 5 - 15 min. The ultrasonic frequency is 20 - 40 kHz, and the power density is 50 - 100 W / cm 2 , and the temperature is controlled at 20 - 30 °C.

[0038] The ultrasonic cavitation effect can break the agglomeration of nanoparticles and improve their uniform distribution; Nitrogen protection can reduce the oxidation of silver particles and improve their long-term conductivity.

[0039] S6: Vacuum degassing & filtration Perform vacuum degassing treatment on the solution (-0.08 to -0.1 MPa, 5 - 10 min), then filter it using a 0.2 - 0.45 μm microporous filter membrane, and finally fill it with nitrogen and seal it for storage.

[0040] Vacuum degassing can remove the bubbles in the solution and improve the uniformity of the potion; Microporous filtration removes insoluble impurities and improves the purity of the potion; Nitrogen filling can prevent the potion from deteriorating due to oxidation and ensure long-term stability.

[0041] Example 1: This example introduces an inorganic potion suitable for the production of ordinary FPC, which takes into account corrosion resistance, conductivity and stability. Specifically, it includes: Formulation composition (parts by mass) Sodium phosphomolybdate (NaPMo 12 O 40 ) 4 parts; Hydrofluoric zirconic acid (H2ZrF6, 0.3 mol / L) 2 parts; Silane coupling agent (KH-550) 1.5 parts; Zinc chloride (ZnCl2) 0.8 parts; Trisodium citrate (C6H5O7Na3) 2.5 parts; Silver nanoparticles (10 nm, carboxyl modified) 0.2 parts; Sodium dodecyl sulfate (SDS) 0.3 parts; The balance is deionized water, making the total mass fraction = 100 parts.

[0042] Dissolution of the main salt: Dissolve sodium phosphomolybdate, zirconium fluoride acid, and zinc chloride in 75 parts of deionized water, stir magnetically for 45 min at a rotation speed of 700 rpm, and adjust the pH to 5.0.

[0043] Complexation control: Add trisodium citrate and continue stirring for 15 min at a temperature of 30 °C to prevent precipitation of metal ions.

[0044] Enhancing adhesion: Add KH-550, maintain the pH at 5.2, and stir for 25 min to promote the hydrolysis of silane and form Si-O-Cu bonds on the copper surface.

[0045] Surface activity regulation: Add SDS and stir for 40 min at a temperature of 28 °C to improve the wettability of the solution.

[0046] Dispersion of silver nanoparticles: Add silver nanoparticles under nitrogen protection and ultrasonically disperse for 10 min at a frequency of 30 kHz and a power of 80 W / cm 2 , at a temperature of 25 °C.

[0047] Vacuum degassing & filtration: Vacuum degas for 7 min (-0.09 MPa), filter through a 0.3 μm microporous membrane, fill with nitrogen and seal, and store in a brown glass bottle at a temperature of 10 °C.

[0048] Example 2: This example focuses on improving the corrosion resistance of the copper surface and is applicable to FPCs working in harsh environments. Specifically, it includes: Formulation composition: Sodium phosphomolybdate 5 parts; Zirconium fluoride acid (0.4 mol / L) 3 parts; Silane coupling agent (KH-570) 2 parts; Zinc chloride 0.6 parts; Trisodium citrate 3 parts; Silver nanoparticles (20 nm) 0.3 parts; Sodium dodecylbenzenesulfonate (SDBS) 0.5 parts; The balance is deionized water, making the total mass fraction = 100 parts.

[0049] Preparation process method: Dissolution of the main salt: Dissolve sodium phosphomolybdate, zirconium fluoride acid, and zinc chloride in 70 parts of deionized water, stir magnetically for 50 min at a rotation speed of 800 rpm, and adjust the pH to 4.8.

[0050] Complex stability: Add trisodium citrate and stir for 20 min at 32 °C to ensure the stability of the solution.

[0051] Enhance the film structure: Add KH-570 and continue stirring for 30 min to form stronger Si-O-Cu bonds and ensure the uniformity of the film.

[0052] Improve dispersibility: Add SDBS and stir for 45 min at 30 °C to prevent the aggregation of silver nanoparticles.

[0053] Dispersion of silver nanoparticles: Add 20 nm silver nanoparticles under nitrogen protection and ultrasonicate for 12 min at a frequency of 35 kHz and a power of 85 W / cm 2 , at a temperature of 27 °C.

[0054] Vacuum degassing & filtration: Perform vacuum treatment for 8 min (-0.1 MPa), filter with a 0.2 μm microporous membrane, seal with nitrogen, store in a PP bottle at 8 °C.

[0055] Example 3: This example focuses on improving the conductivity of the copper surface and is applicable to high-frequency circuit boards. Specifically, it includes: Formulation composition in parts by mass: 3 parts of sodium phosphomolybdate; 1 part of zirconium fluoroacid (0.2 mol / L); 1 part of silane coupling agent (KH-550); 0.7 part of zinc chloride; 2 parts of trisodium citrate; 0.3 part of silver nanoparticle (50 nm); 0.4 part of sodium dodecyl sulfate (SDS); The balance is deionized water, making the total parts by mass = 100 parts.

[0056] The specific preparation process steps are as follows: Dissolution of the main salt: Dissolve sodium phosphomolybdate, zirconium fluoroacid, and zinc chloride in 78 parts of deionized water, stir magnetically for 40 min at a rotation speed of 750 rpm, and adjust the pH to 5.5.

[0057] Complexation regulation: Add trisodium citrate and stir for 10 min at 29 °C to ensure the stability of metal ions.

[0058] Enhance the binding force: Add KH-550 and stir for 20 min to make the Si-O-Cu bonds more uniform and improve the integrity of the film structure.

[0059] Improve conductivity: Add SDS and stir for 35 min at 27 °C to improve the dispersion effect of silver particles.

[0060] Dispersion of silver nanoparticles: Add 50-nm silver nanoparticles under nitrogen protection, and ultrasonicate for 8 min at a frequency of 25 kHz and a power of 75 W / cm 2 , at a temperature of 26 °C.

[0061] Vacuum degassing & filtration: Conduct vacuum treatment for 6 min (-0.08 MPa), filter through a 0.45-μm microporous membrane filter, seal with nitrogen filling, store in a PP bottle, at a temperature of 12 °C.

[0062] Comparative example 1: Formulation of the comparative example: Sodium phosphomolybdate (NaPMo 12 O 40 ) 4 parts; Hydrofluoric zirconic acid (H2ZrF6, 0.3 mol / L) 2 parts; Silane coupling agent (KH-550) 1.5 parts; Zinc chloride (ZnCl2) 1 part; Trisodium citrate (C6H5O7Na3) 2 parts; Silver nanoparticle (10 nm, carboxyl modified) 0.3 part; Sodium dodecyl sulfate (SDS) …… 0.3 part; The balance is deionized water, making the total mass fraction = 100 parts; Main differences from Example 1: Dosage of zinc chloride: In the comparative example, the dosage of zinc chloride is increased to 1 part, aiming to improve the corrosion resistance of the copper surface, but this may have a certain impact on the compactness of the protective film.

[0063] Content of silver nanoparticles: In the comparative example, the dosage of silver nanoparticles is increased to 0.3 part, which may improve the conductivity, but the distribution of silver particles may not be as uniform as in Example 1, resulting in the electrical performance of the film not meeting expectations.

[0064] According to the above content, the specific preparation process is as follows: Dissolution of the main salt: Dissolve sodium phosphomolybdate, hydrofluoric zirconic acid, and zinc chloride in 75 parts of deionized water, stir magnetically for 45 min at a rotation speed of 700 rpm, and adjust the pH to 5.0.

[0065] Complexation control: Add trisodium citrate and continue stirring for 15 min at a temperature of 30 °C to prevent precipitation of metal ions.

[0066] Enhancing adhesion: Add KH-550, maintain the pH at 5.2, and stir for 25 min to promote the hydrolysis of the silane and form Si-O-Cu bonds on the copper surface.

[0067] Surface activity regulation: Add SDS and stir for 40 min at a temperature of 28 °C to improve the wettability of the solution.

[0068] Nano - silver dispersion: Add nano - silver particles under nitrogen protection, and ultrasonically disperse for 10 min at a frequency of 30 kHz and a power of 80 W / cm 2 , at a temperature of 25 °C.

[0069] Vacuum degassing & filtration: Vacuum degas for 7 min (-0.09 MPa), filter through a 0.3 - μm microporous membrane, fill with nitrogen and seal, store in a brown glass bottle at a temperature of 10 °C.

[0070] Comparative Example 2: Comparison of the formula of high - corrosion - resistant FPC inorganic solution Comparative - example formula: Sodium phosphomolybdate (NaPMo 12 O 40 ) 5 parts; Zirconium fluoride acid (0.4 mol / L) 3 parts; Silane coupling agent (KH - 570) 2 parts; Zinc chloride (ZnCl2) 0.8 part; Trisodium citrate (C6H5O7Na3) 3 parts; Nano - silver particles (20 nm) 0.2 part; Sodium dodecylbenzenesulfonate (SDBS) 0.4 part; The balance is deionized water, making the total mass fraction = 100 parts; The main differences from Example 2: Dosage of zinc chloride: In the comparative example, the dosage of zinc chloride is increased to 0.8 part, which can improve corrosion protection, but may lead to too high an ionization degree on part of the copper surface, affecting the uniformity of the protective film.

[0071] Size and content of nano - silver particles: The nano - silver particles used in the comparative example have a size of 20 nm. The larger particle size may lead to an enhanced interaction between silver particles, making it difficult to achieve uniform dispersion and possibly affecting conductivity.

[0072] According to the above content, the specific preparation process method is as follows: Dissolution of main salts: Dissolve sodium phosphomolybdate, zirconium fluoride acid, and zinc chloride in 70 parts of deionized water, magnetically stir for 50 min at a rotation speed of 800 rpm, and adjust the pH to 4.8.

[0073] Complexation and stabilization: Add trisodium citrate and stir for 20 min at a temperature of 32 °C to ensure the stability of the solution.

[0074] Enhance the film - layer structure: Add KH - 570 and continue stirring for 30 min to form stronger Si - O - Cu bonds and ensure the uniformity of the film layer.

[0075] Improve dispersibility: Add SDBS and stir for 45 min at a temperature of 30 °C to prevent nano - silver agglomeration.

[0076] Dispersion of silver nanoparticles: Add 20-nm silver nanoparticles under nitrogen protection, and ultrasonicate for 12 min at a frequency of 35 kHz and a power of 85 W / cm 2 , at a temperature of 27 °C.

[0077] Vacuum degassing & filtration: Conduct vacuum treatment for 8 min (-0.1 MPa), filter through a 0.2-μm microporous membrane filter, seal with nitrogen filling, store in a PP bottle at a temperature of 8 °C.

[0078] Comparative Example 3: Comparison of the formulations of high-conductivity FPC inorganic potions Formulation of the comparative example: Sodium phosphomolybdate (NaPMo 12 O 40 ) 3 parts; Zirconium fluoride (0.2 mol / L) parts; Silane coupling agent (KH-550) 1 part; Zinc chloride (ZnCl2) 0.7 part; Trisodium citrate (C6H5O7Na3) 2 parts; Silver nanoparticles (50 nm) 0.4 part; Sodium dodecyl sulfate (SDS) 0.4 part; The balance is deionized water, making the total mass fraction = 100 parts; Main differences from Example 3: Dosage of zinc chloride: The amount of zinc chloride is increased to 0.7 part in the comparative example, which may improve the corrosion protection performance but will affect the electrochemical behavior of the copper surface and may slightly decrease the conductivity of the film.

[0079] Size of silver nanoparticles: Use 50-nm silver nanoparticles. Larger particle size may result in lower conductivity than silver particles with smaller particle size, and their dispersibility may be affected.

[0080] Preparation process: Dissolution of the main salt: Dissolve sodium phosphomolybdate, zirconium fluoride, and zinc chloride in 78 parts of deionized water, stir magnetically for 40 min at a rotation speed of 750 rpm, and adjust the pH to 5.5.

[0081] Complexation regulation: Add trisodium citrate, stir for 10 min at a temperature of 29 °C to ensure the stability of metal ions.

[0082] Enhance the binding force: Add KH-550 and stir for 20 min to make the Si-O-Cu bond more uniform and improve the structural integrity of the film layer.

[0083] Improve the conductivity: Add SDS and stir for 35 min at a temperature of 27 °C to improve the dispersion effect of silver particles.

[0084] Silver nanowire dispersion: Add 50nm silver nanowires under nitrogen protection, sonicate for 8 minutes at a frequency of 25kHz and a power of 75W / cm 2 , at a temperature of 26°C.

[0085] Vacuum degassing & filtration: Perform vacuum treatment for 6 minutes (-0.08MPa), filter through a 0.45μm microporous membrane, fill with nitrogen and seal, store in a PP bottle at a temperature of 12°C.

[0086] Experiment 1: Corrosion resistance comparison experiment Experiment purpose: Verify the effect of zinc chloride content on the corrosion resistance of the copper surface and observe the tolerance of the protective film in a salt spray environment.

[0087] Experimental procedure: Copper sheet preparation: Select a copper sheet with dimensions of 30×30×0.530×30×0.5mm, ultrasonically clean it with acetone for 10 minutes to remove surface oil.

[0088] Immerse it in dilute hydrochloric acid (5%) for 30 seconds to remove the oxide layer, then rinse with deionized water and dry.

[0089] Coating application: Prepare the solutions of Example 1 and Comparative Example 1 respectively and use them after storing at room temperature (25°C) for 24 hours.

[0090] Immerse the copper sheet in the solution by dip coating for 60 seconds, remove the excess solution by spinning, and air dry for 10 minutes.

[0091] Put it in an oven at 120°C and dry for 10 minutes to ensure coating curing.

[0092] Salt spray test: Use neutral salt spray test (ASTM B117), set the test temperature to 35°C and the relative humidity to 95%.

[0093] Use 5% NaCl solution as the salt spray source and spray continuously for 48 hours.

[0094] Take out the samples every 12 hours, record the surface oxidation degree, and take pictures to analyze the change trend.

[0095] Data recording and analysis: Observe the corrosion morphology of the film layer using a scanning electron microscope (SEM).

[0096] Analyze the elemental composition of the film layer by X-ray photoelectron spectroscopy (XPS) to judge the effect of zinc chloride on the protective film.

[0097] Calculate the corrosion rate of the copper sheet surface, in units of μm / h, to measure the corrosion resistance.

[0098] Table 1: Copper sheet salt spray corrosion test data for different potion formulations (48h) The content of zinc chloride has an obvious influence on the structural stability of the protective film. In Example 1, a lower content of Zn 2+ promotes the complexation reaction between phosphomolybdate and the copper surface, forming a uniform and dense protective film. This film layer effectively blocks the penetration of Cl - and reduces the oxidation rate of copper. In Comparative Example 1, the content of zinc chloride is relatively high, resulting in Zn 2+ competitively coordinating with phosphomolybdate, affecting the denseness of the film, causing microcracks to appear locally in the film layer, and reducing the corrosion resistance.

[0099] SEM observation shows that the surface of the film layer formed in Example 1 is relatively uniform, without obvious pores or cracks, while the film layer of Comparative Example 1 gradually shows cracks in the salt spray environment, eventually leading to local corrosion. The XPS results further verify this point. The Zn content in Comparative Example 1 is as high as 1.8%, indicating that excessive Zn 2+ deposition leads to the instability of the film layer, making it more likely to peel off under corrosion conditions.

[0100] Overall, the addition of zinc chloride needs to be appropriate. Excessive Zn 2+ will interfere with the complex structure of the film layer and reduce its corrosion resistance. This also shows that the main role of sodium phosphomolybdate is to provide a stable inorganic protective layer, while Zn 2+ only acts as an auxiliary component, and excessive amounts will have the opposite effect.

[0101] Experiment 2: Comparison experiment on film adhesion Experimental objective: To investigate the influence of the type of silane coupling agent and the content of zinc chloride on the film adhesion, and to determine the best formulation design.

[0102] Copper sheet treatment: Select electrolytic copper sheets with a specification of 20×20×0.320×20×0.3 mm, and ultrasonically clean them with acetone for 8 min to remove oil stains.

[0103] Alkaline wash with 3% NaOH solution for 30 s, and rinse with deionized water after neutralization.

[0104] Micro-etch with 1% sulfuric acid solution for 20 s to form a uniform and rough surface, and then rinse and dry.

[0105] Potion coating: Take the potions of Example 2 and Comparative Example 2, and coat them on the surface of the copper sheet respectively. Use the spin coating method (1500 rpm, 30 s) to form a uniform coating.

[0106] Let the sample stand for 5 min, and then bake it at 120 °C for 15 min to promote the curing of the film layer.

[0107] Adhesion test: The cross - hatch test method (ASTM D3359 - 09) was used. A 1 - mm cutter was used to scribe a 10×10 grid (100 grids). After the tape was pasted and quickly peeled off, the peeling situation was observed.

[0108] The pull - out force test (ASTM D4541) was carried out. A pull - out head with a diameter of 10 mm was used to measure the maximum force value (unit: MPa) required for film layer peeling.

[0109] SEM observation: The surface morphology of the film layer was observed by a scanning electron microscope (SEM), and the film layer changes under different adhesion forces were analyzed.

[0110] Table 2: Adhesion test results of film layers with different potion formulas The film layer of Example 2 showed excellent adhesion. The structure of KH - 570 silane coupling agent provided a more stable Si - O - Cu bond, making the coating bind tightly to the copper surface and difficult to peel. In contrast, KH - 550 in Comparative Example 2 may have a weaker bonding ability due to different molecular structures, being more likely to break during the pull - out test and showing a lower adhesion strength.

[0111] The influence of zinc chloride content was also very obvious. In Comparative Example 2, the higher zinc chloride content led to excessive Zn 2+ participating in film layer complexation, disturbing the network structure in some areas and reducing the overall uniformity. This non - uniformity was particularly obvious under SEM observation, with micro - cracks appearing in the film layer in some areas and being more likely to peel off under external forces.

[0112] Generally speaking, the choice of silane coupling agent is the key factor affecting adhesion. At the same time, excessive Zn 2+ may damage the stability of the film layer. This indicates that the optimization of the film layer not only needs to consider the strength of chemical bonding, but also needs to ensure the uniform distribution of the complexation structure. Otherwise, the mechanical properties of the film layer may decrease significantly.

[0113] Experiment 3: Conductivity comparison experiment (Example 3 vs Comparative Example 3) Experiment objective: To explore the influence of different nano - silver particle sizes on the conductivity of the coating, and to verify the influence of the size and dispersion of nano - silver particles on the contact resistance.

[0114] Experimental steps Copper sheet treatment: Electrolytic copper sheets with dimensions of 20×20×0.3 mm were selected. The surface was cleaned with an ultrasonic cleaner for 10 minutes to remove grease and impurities.

[0115] Surface de - oxidation treatment was carried out using an ammonia water solution. After removing the oxide layer, it was rinsed with de - ionized water and dried.

[0116] Preparation and coating of solution: Prepare the solution of Example 3 and Comparative Example 3 respectively, and ensure that the concentration and size of the silver particles meet the experimental requirements.

[0117] The solution was evenly coated on the surface of the copper sheet using a spraying method, and the coating thickness was controlled at 1.0 μm.

[0118] After coating, the sample was naturally air-dried for 15 minutes and placed in an oven at 120°C for 10 minutes to solidify the film layer.

[0119] Contact resistance test: The contact resistance test was performed using the four-probe method. The equipment was set to 1 mA current and the temperature was maintained at 25°C.

[0120] Measure the contact resistance value of the sample surface and record the resistance data for each sample.

[0121] Data Analysis: The contact resistance values were compared with the baseline values before the experiment to evaluate the conductive properties of the coating.

[0122] The silver particle distribution was analyzed using a scanning electron microscope (SEM) to ensure that the particles were evenly dispersed and free of agglomerates.

[0123] Table 3: Copper sheet contact resistance data of different solution formulas From the conductivity experiment, the size of the nano silver particles (50nm) in Example 3 is significantly better than the 400nm particles in Comparative Example 3. The fine silver particles can provide higher surface activity, making them more evenly dispersed on the copper surface, forming a more stable conductive channel. In this process, the interaction force between the silver particles is small, avoiding agglomeration and effectively reducing the resistance value.

[0124] In Comparative Example 3, the larger silver particles are too large and easily form aggregates on the surface, resulting in local conductive path blockage. This results in a higher resistance value, indicating that larger silver particles are not ideal in high conductivity applications. Through SEM observation, the silver particles in Example 3 are uniformly distributed, and each silver particle surface can be maximized for electronic conduction. However, the silver particles in Comparative Example 3 are relatively unevenly dispersed, which significantly affects the formation of the conductive path.

[0125] Mechanistically, the effect of the size of nanosilver on conductivity is not only the size of the particles themselves, but also its dispersion and stability. In Example 3, the moderate particle size and good dispersion allow a stronger conductive network to be formed between the silver particles, thereby reducing the contact resistance. In Comparative Example 3, due to the agglomeration of silver particles, the conductive network is destroyed, increasing the resistance. This shows that controlling particle size and dispersion is a key factor in improving conductivity.

[0126] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An FPC inorganic solution, characterized in that, Composed of the following components in parts by mass: 2 - 5 parts of sodium phosphomolybdate; 1 - 3 parts of zirconium fluoride; 0.5 - 2 parts of silane coupling agent, the silane coupling agent is selected from γ-aminopropyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane; 0.5 - 1 part of zinc chloride; 1 - 3 parts of complexing agent, the complexing agent is trisodium citrate; 0.1 - 0.3 parts of silver nanoparticles with a particle size of 10 - 50 nm and surface modified with carboxyl functional groups; 0.2 - 0.5 parts of anionic surfactant; The balance is deionized water, making the total mass fraction of each component 100 parts; Among them, the mass ratio of sodium phosphomolybdate to zirconium fluoride is 2:1 to 5:

3.

2. The FPC inorganic chemical solution according to claim 1, characterized in that The sodium phosphomolybdate is crystalline hydrated sodium phosphomolybdate.

3. An FPC inorganic potion according to claim 1, characterized in that, The concentration of zirconium fluoride is 0.1 - 0.5 mol / L.

4. A kind of FPC inorganic potion according to claim 1, characterized in that, The surface carboxyl functional groups of the silver nanoparticles are modified by the sodium citrate reduction method.

5. An FPC inorganic potion according to claim 1, characterized in that, The anionic surfactant is sodium dodecyl sulfate or sodium dodecylbenzenesulfonate.

6. A preparation process of an FPC inorganic potion, according to any one of claims 1-5, an FPC inorganic potion, characterized in that, Including the following steps: S1. Dissolve sodium phosphomolybdate, zirconium fluoride, and zinc chloride in deionized water, stir magnetically for 30 - 60 min until completely dissolved, and add 0.1 - 0.5 mol / L dilute nitric acid to adjust the pH to 4.5 - 5.5; S2. Add trisodium citrate to the solution in step S1, stir for 10 - 20 min, and control the temperature at 25 - 35 °C; S3. Add γ-aminopropyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane, continue to stir for 10 - 30 min, and maintain the pH at 4.5 - 5.5; S4. Add anionic surfactant, stir for 30 - 60 min, and control the solution temperature at 25 - 35 °C; S5. Under nitrogen protection, add the silver nanoparticles with carboxyl functional groups on the surface to the mixed solution, perform ultrasonic dispersion treatment for 5 - 15 min, with an ultrasonic frequency of 20 - 40 kHz and a power density of 50 - 100 W / cm 2 , and control the temperature at 20 - 30 °C; S6: Perform vacuum degassing treatment on the solution, with a vacuum degree of -0.08 to -0.1 MPa, then filter with a 0.2 - 0.45 μm microporous filter membrane, fill with nitrogen until the oxygen content in the container ≤ 1%, and store it sealed in a light-proof container made of brown glass or polypropylene, with a storage temperature of 5 - 25 °C.

7. A preparation process of FPC inorganic potion according to claim 6, characterized in that, The rotation speed of the magnetic stirring in step S1 is 500 - 800 rpm.

8. The preparation process of an FPC inorganic potion according to claim 6, characterized in that The power density of the ultrasonic dispersion described in step S5 is 70-90 W / cm 2 .

9. A preparation process of FPC inorganic liquid medicine according to claim 6, characterized in that, The duration of the vacuum degassing treatment in step S6 is 5 - 10 min.

10. A preparation process of an FPC inorganic potion according to claim 6, characterized in that, The material of the light-proof container is polypropylene, and the inner wall is coated with an anti-oxidation film layer.

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