Ultra-fine copper foil wire with diameter of 0.02mm to 0.05mm

Abstract

The application discloses an ultra-fine copper foil wire with a diameter of 0.02mm to 0.05mm, and belongs to the technical field of composite wire processing, which is used to solve the technical problem that the corrosion resistance, mechanical strength, electromagnetic shielding performance and insulation strength of the existing ultra-fine copper foil wire need to be further improved. The application comprises a copper foil wire core, a fluorine-containing anticorrosion layer and an outer protective layer. The insulation layer comprises the fluorine-containing anticorrosion layer and the outer protective layer. The fluorine-containing anticorrosion layer is obtained by melting and coating a fluorine-enhanced modified resin on the outside of the copper foil wire core and then solidifying. The application optimizes the material composition of the fluorine-containing anticorrosion layer and the outer protective layer. The fluorine-containing anticorrosion layer and the outer protective layer cooperate with each other, so that the mechanical strength and corrosion resistance of the composite wire are improved, and the electromagnetic shielding performance and insulation strength of the composite wire are also improved.

Description

Technical Field

[0001] This invention relates to the field of composite conductor processing technology, specifically to ultrafine copper foil composite conductors with diameters of 0.02 mm to 0.05 mm. Background Technology

[0002] Ultrafine copper foil wire is a type of wire material that uses ultrafine copper foil wire as the conductive core. Through a specific composite process, the copper foil wire is combined with an insulation layer and a protective sheath. Ultrafine copper foil wire not only retains the advantages of traditional copper foil wire, but also further improves the miniaturization and integration level of the wire.

[0003] The prior art, a Chinese invention patent with publication number CN107170535A, discloses an ultra-fine sheathed core wire and its manufacturing equipment, including a sheath and a core. The cross-section of the wire is circular, the cross-section of the core is circular, and the cross-section of the sheath is annular. The sheath wraps around the outside of the core. The core is made of a conductive material composed of a mixture of carbon black particles and polyaniline. The sheath is made of a polymer insulating material. The outside of the sheath is also provided with wear-resistant grooves, which are wrapped around the outside of the sheath from top to bottom.

[0004] In existing technologies, flexible electronic products such as flexible displays and flexible sensors require conductors with extremely high flexibility and miniaturization. Ultrafine copper foil wires, with their excellent flexibility and miniaturization characteristics, have become ideal connecting wire materials for these products. However, traditional ultrafine copper foil composite wires, which use copper as the main material, are easily corroded by external forces and have low mechanical strength. During use, they are prone to breakage due to external forces. At the same time, in highly integrated circuit environments, signal transmission is easily affected by electromagnetic interference. Traditional composite wires often improve electromagnetic shielding performance by adding conductive particles to the material, sacrificing the insulation resistance of the outer insulation layer. As a result, the insulation performance of composite wires needs further improvement.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide an ultra-fine copper foil wire composite conductor with a diameter of 0.02 mm to 0.05 mm, which solves the technical problems of poor corrosion resistance and mechanical strength of existing ultra-fine copper foil wire composite conductors, as well as the need to further improve the electromagnetic shielding performance and insulation strength of composite conductors.

[0007] The objective of this invention can be achieved through the following technical solution: an ultra-fine copper foil wire composite conductor with a diameter of 0.02 mm to 0.05 mm, comprising a copper foil wire core, a fluorinated anti-corrosion layer, and an outer protective layer. The insulation layer comprises a fluorinated anti-corrosion layer and an outer protective layer. The fluorinated anti-corrosion layer is obtained by melting and coating a fluorine-reinforced modified resin onto the outside of the copper foil wire core and then curing it. The outer surface of the fluorinated anti-corrosion layer is provided with several grooves arranged parallel to the copper foil wire core. The outer protective layer is obtained by melting and coating a composite polyethylene onto the outside of the fluorinated anti-corrosion layer and then curing it.

[0008] The composite polyethylene is composed of 100 parts by weight of a polyethylene mixture and 10-15 parts by weight of epoxy resin, wherein the polyethylene mixture is composed of 100 parts by weight of low-density polyethylene, 30-40 parts by weight of modified polyethylene and 12-16 parts by weight of modified graphite.

[0009] Furthermore, the fluorine-reinforced modified resin is obtained by the following steps:

[0010] A1. Add butyl acrylate, perfluorooctyl acrylate, vinyl-terminated silicone oil, oleylamine and toluene to a nitrogen-protected reactor and stir. Raise the reactor temperature to 75-85℃, add an initiator to the reactor, keep the reaction at this temperature for 6-8 hours, and then perform post-treatment to obtain a fluorinated resin.

[0011] The synthesis reaction formula for fluorinated resins is as follows:

[0012]

[0013] In the formula:

[0014] The synthesis reaction principle of fluorinated resins is as follows:

[0015] Under the action of an initiator, free radical polymerization is initiated using the olefin double bonds on butyl acrylate, perfluorooctyl acrylate, terminal vinyl silicone oil, and oleylamine molecules as active reaction sites to form polyolefin segments crosslinked with polysiloxane segments. Furthermore, the polyolefin segments are modified with fluorinated branches, alkane branches, and octylamine branches to prepare a fluorinated resin.

[0016] A2. Add fluorinated resin and epoxy resin to the reactor and stir. Raise the temperature of the reactor to 190-200℃ and melt and stir for 30-50 minutes to obtain fluorinated reinforced modified resin.

[0017] Further, in step A1, the ratio of butyl acrylate, perfluorooctyl acrylate, vinyl-terminated silicone oil, oleylamine, toluene, and initiator is 60-70g:15-18g:10-12g:17-19g:500mL:0.8-1.2g, and the initiator is azobisisobutyronitrile. The post-treatment includes: after the reaction is complete, raising the temperature of the reaction vessel to 80-90℃, removing the solvent under reduced pressure to obtain a fluorinated resin; in step A2, the weight ratio of the fluorinated resin to the epoxy resin is 7:2-3, and the epoxy resin is bisphenol A type epoxy resin E-51.

[0018] Furthermore, modified polyethylene is obtained through the following steps:

[0019] B1. After uniformly mixing low-density polyethylene powder, tea polyphenols, glycidyl methacrylate and initiator, add them to a mixer at a temperature of 185-195℃, set the speed of the mixer to 50-60 r / min, and mix for 10-15 min to obtain a mixture.

[0020] B2. Transfer the mixture to a flat vulcanizing machine. Raise the temperature of the flat vulcanizing machine to 190-200℃ and the pressure to 9-10MPa. Hold the mixture under heat and pressure for 5-10 minutes. The post-processing yields modified polyethylene.

[0021] The synthesis reaction mechanism of modified polyethylene is as follows:

[0022] Using tea polyphenols as antioxidants, low-density polyethylene powder, glycidyl methacrylate, and an initiator were mixed evenly. The olefin double bonds on glycidyl methacrylate were used as active reaction sites. After vulcanization treatment, the glycidyl methacrylate and low-density polyethylene molecular chains were cross-linked and bonded. A large number of epoxy groups were modified on the polyethylene molecular chains to prepare modified polyethylene.

[0023] Further, in step B1, the weight ratio of the low-density polyethylene powder, tea polyphenols, glycidyl methacrylate, and initiator is 100:1:5-7:0.5, and the initiator is benzoyl peroxide; in step B2, the post-treatment includes: after vulcanization, cooling and discharging the material, pulverizing, adding the powder and xylene at a concentration of 1g:200mL to the reaction vessel and stirring, raising the temperature of the reaction vessel to reflux, keeping it warm and stirring until the system is dissolved, lowering the temperature of the reaction vessel to room temperature, adding petroleum ether to the reaction vessel, a large amount of solid precipitates, filtering, transferring the filter cake to a drying oven at a temperature of 60-70℃, drying to constant weight, and obtaining modified polyethylene.

[0024] Furthermore, modified graphite is obtained through the following steps:

[0025] C1. Add flake graphite powder and modifier to the reaction vessel, stir at room temperature for 30-40 minutes, and then perform post-treatment to obtain activated graphite powder;

[0026] C2. Place the activated graphite powder into a tube furnace under a nitrogen atmosphere, raise the temperature of the tube furnace to 300-350℃, hold for 10-20 minutes, cool down and discharge to obtain expanded graphite.

[0027] C3. Add expanded graphite, iron pentacarbonyl, and kerosene to a high-pressure reactor under nitrogen protection and stir in a closed manner. Raise the temperature of the high-pressure reactor to 260-280℃ and keep it at that temperature for 90-120 minutes. The post-treatment yields supported expanded graphite.

[0028] The synthesis reaction mechanism of supported expanded graphite is as follows:

[0029] Flake graphite powder is mixed with a modifier and stirred at room temperature. The oxidizing substances in the modifier attack the carbon atoms of graphite, forming carbon-oxygen bonds, increasing the active sites on the graphite surface, and changing the surface properties of graphite, thus providing conditions for subsequent high-temperature expansion. The carbon atoms on the graphite surface are further oxidized by hydrogen peroxide to form more carbon-oxygen bonds and carboxyl functional groups, resulting in activated graphite powder. At high temperature, water vapor, carbon dioxide and other oxidation products between graphite layers escape rapidly, generating huge internal pressure. At the same time, the carbon atoms between graphite layers rearrange at high temperature to form a more porous structure, causing the graphite to expand rapidly at high temperature, forming expanded graphite. At high temperature, iron pentacarbonyl decomposes to produce iron atoms or iron nanoparticles and carbon monoxide. The iron atoms or iron nanoparticles produced are adsorbed on the expanded graphite to form supported expanded graphite.

[0030] C4. Add supported expanded graphite, modified nano silica, tetraethyl orthosilicate, and anhydrous ethanol to a reaction vessel, ultrasonically disperse for 30-50 min, stir, raise the temperature of the reaction vessel to 50-60℃, add catalyst to the reaction vessel, keep the reaction at this temperature for 60-90 min, and then perform post-treatment to obtain modified graphite.

[0031] The synthesis reaction mechanism of modified graphite is as follows:

[0032] Under alkaline conditions, the siloxane bonds in modified nano-silica and tetraethyl orthosilicate molecules hydrolyze to generate silanol groups, which then undergo condensation reactions with the active oxygen-containing groups on the surface of supported expanded graphite, thereby coating the surface of supported expanded graphite with a layer of nano-silica and a polysiloxane coating layer to prepare modified graphite.

[0033] Further, in step C1, the ratio of the flake graphite powder to the modifier is 1g:8-12mL. The modifier is obtained by uniformly mixing potassium permanganate and 80-90wt% sulfuric acid at a ratio of 1g:7mL. The post-treatment includes: after the reaction is complete, filtering until no liquid drips, adding the filter cake and 20-30wt% hydrogen peroxide at a ratio of 1g:8-10mL to the reaction vessel and stirring, raising the temperature of the reaction vessel to 75-85℃, stirring for 60-80min, lowering the temperature of the reaction vessel to room temperature, filtering, washing the filter cake with purified water until neutral, drying it, transferring the filter cake to a drying oven at 70-80℃, and vacuum drying to constant weight to obtain activated graphite powder; in step C3, the ratio of the expanded graphite, iron pentacarbonyl, and kerosene is 7g:1g: 500 mL, the post-treatment includes: after the reaction is complete, the pressure of the high-pressure reactor is reduced to room temperature, centrifuged, the solid is washed 5 times with acetone and then dried under vacuum, the filter cake is transferred to a drying oven at a temperature of 60-70℃ and vacuum dried to constant weight to obtain supported expanded graphite; in step C4, the ratio of the amount of supported expanded graphite, modified nano silica, tetraethyl orthosilicate, anhydrous ethanol and catalyst is 10g:4g:3g:100mL:10mL, the catalyst is 0.3-0.5mol / L sodium hydroxide solution, the post-treatment includes: after the reaction is complete, the temperature of the reactor is reduced to room temperature, filtered, the filter cake is washed with purified water until neutral and then dried under vacuum, the filter cake is placed in a drying oven at a temperature of 70-80℃ and vacuum dried to constant weight to obtain modified graphite.

[0034] Furthermore, the modified nano-silica is obtained by the following steps:

[0035] D1. Add nano-silica, anhydrous ethanol and 3-aminopropyltriethoxysilane to a reaction vessel and stir. Raise the temperature of the reaction vessel to 50-60℃, add a catalyst to the reaction vessel, keep the temperature for 50-60 min, and then process to obtain activated silica powder.

[0036] D2. Add activated silica powder and toluene to a nitrogen-protected reactor and stir. At room temperature, add propyltriethoxysilane isocyanate to the reactor and stir for 40-50 minutes. After post-treatment, modified nano silica is obtained.

[0037] The synthesis reaction mechanism of modified silica is as follows:

[0038] Activated silica powder with a large number of amino groups on its surface was prepared by coating nano-silica with 3-aminopropyltriethoxysilane. Under nitrogen protection, the isocyanate groups on propyltriethoxysilane reacted with the amino groups on the surface of the activated silica powder to prepare modified nano-silica of triethoxysilane-modified activated silica powder.

[0039] Further, in step D1, the ratio of nano-silica, anhydrous ethanol, 3-aminopropyltriethoxysilane, and catalyst is 5g:30mL:1g:5mL, and the catalyst is a 0.3-0.5mol / L sodium hydroxide solution. The post-treatment includes: after the reaction is complete, the temperature of the reaction vessel is lowered to room temperature, the mixture is filtered, the filter cake is washed with purified water until neutral, and then dried under vacuum. The filter cake is placed in a drying oven at a temperature of 70-80℃ and dried under vacuum until constant weight to obtain activated silica powder. In step D2, the ratio of activated silica powder, toluene, and propyltriethoxysilane is 5g:50mL:2g. The post-treatment includes: after the reaction is complete, the mixture is filtered, the filter cake is washed with toluene three times, and then dried under vacuum. The filter cake is transferred to a drying oven at a temperature of 70-80℃ and dried under vacuum until constant weight to obtain modified nano-silica.

[0040] Furthermore, the overall outer diameter of the conductor is 0.02mm-0.05mm, such as 0.02mm, 0.03mm, 0.04mm, and 0.05mm. It has good flexibility, good flexural strength, good tensile strength, and good conductivity.

[0041] The present invention has the following beneficial effects:

[0042] 1. The ultrafine copper foil composite conductor of the present invention uses fine copper foil wire as the conductor core, and forms a fluorinated anti-corrosion layer and an outer protective layer sequentially by thermal coating on its exterior. By optimizing the forming structure of the fluorinated anti-corrosion layer and the material composition of the fluorinated anti-corrosion layer and the outer protective layer, the contact area between the fluorinated anti-corrosion layer and the outer protective layer is increased, while ensuring close contact between the fluorinated anti-corrosion layer and the outer protective layer, thereby improving the mechanical strength and corrosion resistance of the material. By optimizing the preparation method of the raw materials of the outer protective layer, the electromagnetic shielding effectiveness of the composite conductor is improved, while the insulation strength of the composite conductor material is increased.

[0043] 2. In the preparation process of the ultrafine copper foil composite conductor of the present invention, perfluorooctyl acrylate is introduced into the fluorinated resin as a fluorinated monomer to improve the resin's weather resistance, chemical corrosion resistance, and thermal stability. At the same time, the addition of butyl acrylate and vinyl-terminated silicone oil can improve the resin's flexibility and processability, and increase the tensile strength of the composite conductor. By introducing bisphenol A epoxy resin, under high temperature conditions, the epoxy resin undergoes ring-opening condensation with active groups such as amino and hydroxyl groups to form cross-linked bonds and hydroxyl groups, thereby enhancing the cross-linking density and intermolecular forces of the resin, and further improving the tensile strength of the composite conductor. In addition, the high electronegativity and low polarizability of fluorine atoms give the fluorinated resin excellent insulation properties, thereby improving the volume resistivity of the composite conductor. The bisphenol A epoxy resin itself also has certain corrosion resistance and insulation properties, and its interaction with the fluorinated resin further improves its corrosion resistance and insulation strength.

[0044] 3. The ultrafine copper foil composite wire of the present invention uses modified graphite and modified polyethylene as reinforcing modifiers to strengthen low-density polyethylene. Under high temperature, the epoxy groups on the modified polyethylene molecules and the imino groups on the modified graphite molecules undergo ring-opening condensation, forming a cross-linked reinforcing network in the low-density polyethylene material to obtain a polyethylene mixture. Both graphite and polysiloxane have good chemical stability. The formation of the multiphase structure of the composite polyethylene and the interaction of each component form a protective layer outside the fluorinated anti-corrosion layer, further improving the corrosion resistance of the composite wire. Bisphenol A type epoxy resin is used to reinforce the polyethylene mixture to prepare composite polyethylene. The siloxane bonds in the composite polyethylene molecules are catalyzed by high temperature and water vapor. Under certain conditions, it decomposes into highly reactive silanol groups, which react with active groups such as hydroxyl and imino groups on the surface of the fluorinated anticorrosive layer or in the molecules of composite polyethylene to form cross-linked bonds, thereby increasing the degree of cross-linking of the material and thus improving its mechanical strength. In the preparation of modified graphite, metal particles are loaded onto the graphite to improve its conductivity. The loaded expanded graphite is modified by coating it with nano-silica particles and polysiloxane. While providing insulation protection for the loaded expanded graphite, the surface activity of the graphite allows it to be uniformly dispersed in the modified polyethylene, thereby forming a conductive network in the outer protective layer. This effectively reflects and absorbs electromagnetic waves, improving the electromagnetic shielding performance of the material while ensuring its insulation performance. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a three-dimensional structural diagram of the ultra-fine copper foil wire composite conductor of the present invention;

[0047] Figure 2 This is a schematic diagram of the cross-sectional structure of the ultra-fine copper foil composite conductor in this invention.

[0048] In the diagram: 100, copper foil wire core; 200, fluorine-containing anti-corrosion layer; 300, outer protective layer. Detailed Implementation

[0049] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In this application, the vinyl-terminated silicone oil is selected from divinyl-terminated polydimethylsiloxane from Greenlink (Jining) Chemical Technology Co., Ltd., with a viscosity (25℃): 100±10MPa·S and vinyl content (molar ratio): 2.60±0.20%; the low-density polyethylene powder is selected from Dongguan Weicai Plastic Raw Materials Co., Ltd., branded as Sinopec Maoming, with a density of 0.918g / cm³. 3 Melting point 122℃.

[0051] Example 1

[0052] This embodiment provides a method for preparing a fluorine-reinforced modified resin for ultrafine copper foil composite wires, comprising the following steps:

[0053] A1. Preparation of fluorinated resins

[0054] Weigh out 600g of butyl acrylate, 150g of perfluorooctyl acrylate, 100g of vinyl-terminated silicone oil, 170g of oleylamine, and 5L of toluene and add them to a nitrogen-protected reactor. Stir the reactor and raise the temperature to 75°C. Add 8g of azobisisobutyronitrile to the reactor and keep it at this temperature for 6 hours. After the reaction is complete, raise the temperature of the reactor to 80°C and remove the solvent under reduced pressure to obtain a fluorinated resin.

[0055] A2, Fluorine-reinforced modified resin

[0056] Fluorinated resin and bisphenol A type epoxy resin E-51 were added to a reaction vessel at a weight ratio of 7:2 and stirred. The temperature of the reaction vessel was raised to 190℃ and stirred for 30 minutes to obtain fluorine-reinforced modified resin.

[0057] Example 2

[0058] This embodiment provides a method for preparing a fluorine-reinforced modified resin for ultrafine copper foil composite wires, comprising the following steps:

[0059] A1. Preparation of fluorinated resins

[0060] Weigh out 650g of butyl acrylate, 165g of perfluorooctyl acrylate, 110g of vinyl-terminated silicone oil, 180g of oleylamine, and 5L of toluene and add them to a nitrogen-protected reactor. Stir the reactor and raise the temperature to 80°C. Add 10g of azobisisobutyronitrile to the reactor and keep it at this temperature for 7 hours. After the reaction is complete, raise the temperature of the reactor to 85°C and remove the solvent under reduced pressure to obtain a fluorinated resin.

[0061] A2, Fluorine-reinforced modified resin

[0062] Fluorinated resin and bisphenol A type epoxy resin E-51 were added to a reaction vessel at a weight ratio of 7:2.5 and stirred. The temperature of the reaction vessel was raised to 195℃ and stirred for 40 minutes to obtain fluorine-reinforced modified resin.

[0063] Example 3

[0064] This embodiment provides a method for preparing a fluorine-reinforced modified resin for ultrafine copper foil composite wires, comprising the following steps:

[0065] A1. Preparation of fluorinated resins

[0066] Weigh out 700g of butyl acrylate, 7180g of perfluorooctyl acrylate, 120g of vinyl-terminated silicone oil, 190g of oleylamine, and 5L of toluene and add them to a nitrogen-protected reactor. Stir the reactor and raise the temperature to 85°C. Add 12g of azobisisobutyronitrile to the reactor and keep it at this temperature for 8 hours. After the reaction is complete, raise the temperature of the reactor to 90°C and remove the solvent under reduced pressure to obtain a fluorinated resin.

[0067] A2, Fluorine-reinforced modified resin

[0068] Fluorinated resin and bisphenol A type epoxy resin E-51 were added to a reaction vessel at a weight ratio of 7:3 and stirred. The temperature of the reaction vessel was raised to 200℃ and stirred for 50 minutes to obtain fluorine-reinforced modified resin.

[0069] Example 4

[0070] This embodiment provides a method for preparing composite polyethylene for ultrafine copper foil wire composite conductors, including the following steps:

[0071] B1. Preparation of modified polyethylene

[0072] Low-density polyethylene powder, tea polyphenols, glycidyl methacrylate and benzoyl peroxide were added evenly in a weight ratio of 100:1:5:0.5 into a mixer at a temperature of 185℃. The mixer speed was set to 50 r / min and the mixture was mixed for 10 min to obtain the mixture.

[0073] The mixture was transferred to a flat vulcanizing machine, where the temperature was raised to 190°C and the pressure to 9 MPa. The mixture was kept at this temperature and pressure for 5 minutes, then cooled and discharged. The mixture was then pulverized. The powder and xylene were added to a reaction vessel at a ratio of 1 g to 200 mL and stirred. The temperature of the reaction vessel was raised to reflux and stirred until the system dissolved. The temperature of the reaction vessel was then lowered to room temperature. An equal volume of petroleum ether to xylene was added to the reaction vessel, resulting in the precipitation of a large amount of solid. The solid was filtered, and the filter cake was transferred to a drying oven at 60°C and dried to constant weight to obtain modified polyethylene.

[0074] B2. Preparation of expanded graphite

[0075] Potassium permanganate and 80wt% sulfuric acid were mixed evenly at a ratio of 1g:7mL to obtain the modifier;

[0076] Flake graphite powder and modifier were added to a reaction vessel at a ratio of 1 g: 8 mL and stirred at room temperature for 30 min. After the reaction was completed, the mixture was filtered until no liquid dripped. The filter cake and 20 wt% hydrogen peroxide were added to the reaction vessel at a ratio of 1 g: 8 mL and stirred. The temperature of the reaction vessel was raised to 75°C and stirred for 60 min. The temperature of the reaction vessel was lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried under vacuum. The filter cake was transferred to a drying oven at 70°C and dried under vacuum until constant weight to obtain activated graphite powder.

[0077] Activated graphite powder is placed in a tube furnace under a nitrogen atmosphere. The temperature of the tube furnace is raised to 300°C and held for 10 minutes. The powder is then cooled and discharged to obtain expanded graphite.

[0078] B3. Preparation of supported expanded graphite

[0079] Weigh out 70g of expanded graphite, 10g of iron pentacarbonyl, and 5L of kerosene and add them to a nitrogen-protected high-pressure reactor. Stir the mixture in a closed container. Raise the temperature of the high-pressure reactor to 260℃. During the heating process, control the pressure of the high-pressure reactor to be below 0.2MPa through the pressure relief valve. Keep the reactor at this temperature for 90 minutes. After the reaction is complete, reduce the pressure of the high-pressure reactor to room temperature, centrifuge, wash the solid with acetone five times, and then dry it. Transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain supported expanded graphite.

[0080] B4. Preparation of modified nano-silica

[0081] Weigh out 50g of nano-silica, 300mL of anhydrous ethanol and 10g of 3-aminopropyltriethoxysilane and add them to the reaction vessel and stir. Raise the temperature of the reaction vessel to 50℃ and add 50mL of 0.3mol / L sodium hydroxide solution to the reaction vessel. Keep the temperature for 50min. After the reaction is complete, lower the temperature of the reaction vessel to room temperature, filter, wash the filter cake with purified water until neutral and then dry it. Place the filter cake in a drying oven at 70℃ and vacuum dry it to constant weight to obtain activated silica powder.

[0082] Weigh 50g of activated silica powder and 500mL of toluene and add them to a nitrogen-protected reaction vessel and stir. At room temperature, add 20g of propyltriethoxysilane isocyanate to the reaction vessel and stir for 40min. After the reaction is complete, filter the mixture and wash the filter cake three times with toluene. Then dry the filter cake and transfer it to a drying oven at 70℃. Vacuum dry the cake to constant weight to obtain modified nano silica.

[0083] B5. Preparation of modified graphite

[0084] Weigh out 100g of supported expanded graphite, 40g of modified nano silica, 30g of tetraethyl orthosilicate, and 1000mL of anhydrous ethanol and add them to a reaction vessel. After ultrasonic dispersion for 30min, stir. Raise the temperature of the reaction vessel to 50℃, add 10mL of 0.3mol / L sodium hydroxide solution to the reaction vessel, and keep the reaction at this temperature for 60min. After the reaction is complete, lower the temperature of the reaction vessel to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Place the filter cake in a drying oven at 70℃ and vacuum dry it to constant weight to obtain modified graphite.

[0085] B6. Preparation of composite polyethylene

[0086] Weigh out 100 parts by weight of low-density polyethylene, 30 parts by weight of modified polyethylene and 12 parts by weight of modified graphite and add them to a twin-screw extruder. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are 190℃, 195℃, 195℃, 195℃, 195℃ and 200℃ respectively. The spindle speed of the twin-screw extruder is 15 r / min. After melt extrusion, the mixture is crushed to obtain a polyethylene mixture.

[0087] Weigh out 100 parts by weight of polyethylene mixture and 10 parts by weight of bisphenol A type epoxy resin E-51, add them to the reaction vessel and stir. Raise the temperature of the reaction vessel to 190℃ and melt and stir for 30 minutes to obtain composite polyethylene.

[0088] Example 5

[0089] This embodiment provides a method for preparing composite polyethylene for ultrafine copper foil wire composite conductors, including the following steps:

[0090] B1. Preparation of modified polyethylene

[0091] Low-density polyethylene powder, tea polyphenols, glycidyl methacrylate and benzoyl peroxide were uniformly added to a mixer at a temperature of 190℃ in a weight ratio of 100:1:6:0.5. The mixer speed was set to 55 r / min and the mixture was mixed for 13 min to obtain the mixture.

[0092] The mixture was transferred to a flat vulcanizing machine, where the temperature was raised to 195°C and the pressure to 9.5 MPa. The mixture was held at this temperature and pressure for 8 minutes, then cooled and discharged. The powder was pulverized, and the powder and xylene were added to a reaction vessel at a ratio of 1 g: 200 mL. The reaction vessel temperature was raised to reflux, and the mixture was stirred until dissolved. The reaction vessel temperature was lowered to room temperature, and petroleum ether of equal volume to xylene was added to the reaction vessel. A large amount of solid precipitated out. The solid was filtered, and the filter cake was transferred to a drying oven at 65°C and dried to constant weight to obtain modified polyethylene.

[0093] B2. Preparation of expanded graphite

[0094] Potassium permanganate and 80-90 wt% sulfuric acid were mixed evenly at a ratio of 1 g: 7 mL to obtain the modifier;

[0095] Flake graphite powder and modifier were added to a reaction vessel at a ratio of 1g:10mL and stirred at room temperature for 35min. After the reaction was completed, the mixture was filtered until no liquid dripped. The filter cake and 25wt% hydrogen peroxide were added to the reaction vessel at a ratio of 1g:9mL and stirred. The temperature of the reaction vessel was raised to 80℃ and stirred for 70min. The temperature of the reaction vessel was lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried under vacuum. The filter cake was transferred to a drying oven at 75℃ and vacuum dried to constant weight to obtain activated graphite powder.

[0096] Activated graphite powder is placed in a tube furnace under a nitrogen atmosphere. The temperature of the tube furnace is raised to 330°C and held for 15 minutes. The powder is then cooled and discharged to obtain expanded graphite.

[0097] B3. Preparation of supported expanded graphite

[0098] Weigh out 70g of expanded graphite, 10g of iron pentacarbonyl, and 5L of kerosene and add them to a nitrogen-protected high-pressure reactor. Stir the mixture in a closed container. Raise the temperature of the high-pressure reactor to 270℃. During the heating process, control the pressure of the high-pressure reactor to be below 0.2MPa through the pressure relief valve. Keep the reactor at this temperature for 105min. After the reaction is complete, reduce the pressure of the high-pressure reactor to room temperature, centrifuge, wash the solid with acetone 5 times, and then dry it. Transfer the filter cake to a drying oven at 65℃ and vacuum dry it to constant weight to obtain supported expanded graphite.

[0099] B4. Preparation of modified nano-silica

[0100] Weigh out 50g of nano-silica, 300mL of anhydrous ethanol and 10g of 3-aminopropyltriethoxysilane and add them to the reaction vessel and stir. Raise the temperature of the reaction vessel to 50-60℃, add 50mL of 0.4mol / L sodium hydroxide solution to the reaction vessel, keep the temperature for 55min, and after the reaction is complete, lower the temperature of the reaction vessel to room temperature, filter, wash the filter cake with purified water until neutral and then dry it. Place the filter cake in a drying oven at 75℃ and vacuum dry it to constant weight to obtain activated silica powder.

[0101] Weigh 50g of activated silica powder and 500mL of toluene and add them to a nitrogen-protected reaction vessel and stir. At room temperature, add 20g of propyltriethoxysilane isocyanate to the reaction vessel and stir for 45min. After the reaction is complete, filter the mixture and wash the filter cake three times with toluene. Then dry the filter cake and transfer it to a drying oven at 75℃. Vacuum dry the cake to constant weight to obtain modified nano silica.

[0102] B5. Preparation of modified graphite

[0103] Weigh out 100g of supported expanded graphite, 40g of modified nano silica, 30g of tetraethyl orthosilicate, and 1000mL of anhydrous ethanol and add them to a reaction vessel. After ultrasonic dispersion for 30-50min, stir. Raise the temperature of the reaction vessel to 50-60℃, add 10mL of 0.4mol / L sodium hydroxide solution to the reaction vessel, and keep the reaction at this temperature for 75min. After the reaction is complete, lower the temperature of the reaction vessel to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Place the filter cake in a drying oven at 75℃ and vacuum dry it to constant weight to obtain modified graphite.

[0104] B6. Preparation of composite polyethylene

[0105] Weigh out 100 parts by weight of low-density polyethylene, 35 parts by weight of modified polyethylene and 14 parts by weight of modified graphite and add them to a twin-screw extruder. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are 190℃, 195℃, 195℃, 195℃, 195℃ and 200℃ respectively. The spindle speed of the twin-screw extruder is 15 r / min. After melt extrusion, the mixture is crushed to obtain a polyethylene mixture.

[0106] Weigh out 100 parts by weight of polyethylene mixture and 13 parts by weight of bisphenol A type epoxy resin E-51, add them to the reaction vessel and stir. Raise the temperature of the reaction vessel to 195℃ and melt and stir for 40 minutes to obtain composite polyethylene.

[0107] Example 6

[0108] This embodiment provides a method for preparing composite polyethylene for ultrafine copper foil wire composite conductors, including the following steps:

[0109] B1. Preparation of modified polyethylene

[0110] Low-density polyethylene powder, tea polyphenols, glycidyl methacrylate and benzoyl peroxide were added evenly in a weight ratio of 100:1:7:0.5 into a mixer at a temperature of 195℃. The mixer speed was set to 60 r / min and the mixture was mixed for 15 min to obtain the mixture.

[0111] The mixture was transferred to a flat vulcanizing machine, where the temperature was raised to 200℃ and the pressure to 10MPa. The mixture was kept at this temperature and pressure for 10 minutes, then cooled and discharged. The mixture was then pulverized. The powder and xylene were added to a reaction vessel at a ratio of 1g:200mL and stirred. The temperature of the reaction vessel was raised to reflux and stirred until the system dissolved. The temperature of the reaction vessel was then lowered to room temperature. Petroleum ether of equal volume to xylene was added to the reaction vessel, resulting in the precipitation of a large amount of solid. The solid was filtered, and the filter cake was transferred to a drying oven at 70℃ and dried to constant weight to obtain modified polyethylene.

[0112] B2. Preparation of expanded graphite

[0113] Potassium permanganate and 90wt% sulfuric acid were mixed evenly at a ratio of 1g:7mL to obtain the modifier;

[0114] Flake graphite powder and modifier were added to a reaction vessel at a ratio of 1g:12mL and stirred at room temperature for 40min. After the reaction was completed, the mixture was filtered until no liquid dripped. The filter cake and 30wt% hydrogen peroxide were added to the reaction vessel at a ratio of 1g:10mL and stirred. The temperature of the reaction vessel was raised to 85℃ and stirred for 80min. The temperature of the reaction vessel was lowered to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried under vacuum. The filter cake was transferred to a drying oven at 80℃ and dried under vacuum until constant weight to obtain activated graphite powder.

[0115] Activated graphite powder is placed in a tube furnace under a nitrogen atmosphere. The temperature of the tube furnace is raised to 350°C and held for 20 minutes. The powder is then cooled and discharged to obtain expanded graphite.

[0116] B3. Preparation of supported expanded graphite

[0117] Weigh out 70g of expanded graphite, 10g of iron pentacarbonyl, and 5L of kerosene and add them to a nitrogen-protected high-pressure reactor. Stir the mixture in a closed container. Raise the temperature of the high-pressure reactor to 280℃. During the heating process, control the pressure of the high-pressure reactor to be below 0.2MPa through the pressure relief valve. Keep the reactor at this temperature for 120min. After the reaction is complete, reduce the pressure of the high-pressure reactor to room temperature, centrifuge, wash the solid with acetone 5 times, and then dry it. Transfer the filter cake to a drying oven at 70℃ and vacuum dry it to constant weight to obtain supported expanded graphite.

[0118] B4. Preparation of modified nano-silica

[0119] Weigh out 50g of nano-silica, 300mL of anhydrous ethanol and 10g of 3-aminopropyltriethoxysilane and add them to the reaction vessel and stir. Raise the temperature of the reaction vessel to 60℃ and add 50mL of 0.5mol / L sodium hydroxide solution to the reaction vessel. Keep the reaction vessel at this temperature for 60min. After the reaction is complete, lower the temperature of the reaction vessel to room temperature, filter the mixture, wash the filter cake with purified water until neutral and then dry it. Place the filter cake in a drying oven at 80℃ and vacuum dry it to constant weight to obtain activated silica powder.

[0120] Weigh 50g of activated silica powder and 500mL of toluene and add them to a nitrogen-protected reaction vessel and stir. At room temperature, add 20g of propyltriethoxysilane isocyanate to the reaction vessel and stir for 50min. After the reaction is complete, filter the mixture and wash the filter cake three times with toluene. Then dry the filter cake and transfer it to a drying oven at 80℃. Vacuum dry the cake to constant weight to obtain modified nano silica.

[0121] B5. Preparation of modified graphite

[0122] Weigh out 100g of supported expanded graphite, 40g of modified nano silica, 30g of tetraethyl orthosilicate, and 1000mL of anhydrous ethanol and add them to a reaction vessel. After ultrasonic dispersion for 50min, stir. Raise the temperature of the reaction vessel to 60℃, add 10mL of 0.5mol / L sodium hydroxide solution to the reaction vessel, and keep the reaction at this temperature for 90min. After the reaction is complete, lower the temperature of the reaction vessel to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Place the filter cake in a drying oven at 80℃ and vacuum dry it to constant weight to obtain modified graphite.

[0123] B6. Preparation of composite polyethylene

[0124] Weigh out 100 parts by weight of low-density polyethylene, 40 parts by weight of modified polyethylene and 16 parts by weight of modified graphite and add them to a twin-screw extruder. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are 190℃, 195℃, 195℃, 195℃, 195℃ and 200℃ respectively. The spindle speed of the twin-screw extruder is 15 r / min. After melt extrusion, the mixture is crushed to obtain a polyethylene mixture.

[0125] Weigh out 100 parts by weight of polyethylene mixture and 15 parts by weight of bisphenol A type epoxy resin E-51, add them to the reaction vessel and stir. Raise the temperature of the reaction vessel to 200℃ and melt and stir for 50 minutes to obtain composite polyethylene.

[0126] Example 7

[0127] Please see the appendix Figure 1-2 This embodiment provides a method for preparing ultrafine copper foil composite wires, including the following steps:

[0128] S1. The fluorine-reinforced modified resin prepared in Example 1 is added to a melting furnace at a temperature of 190°C and heated until the fluorine-reinforced modified resin melts to obtain a fluid fluorine-reinforced modified resin coating liquid.

[0129] S2. The composite polyethylene prepared in Example 4 is added to a melting furnace at a temperature of 190°C and heated until the composite polyethylene melts to obtain a fluid composite polyethylene coating liquid.

[0130] S3. Select copper foil wire with a diameter of 0.02 mm as copper foil wire core 100, heat it to 500℃, keep it at that temperature for 2 minutes, pass it through a melting furnace containing fluorine-enhanced modified resin coating liquid, and then pass it through a forming hole. After water cooling and curing, a fluorine-containing anti-corrosion layer 200 with a thickness of 0.008 mm is formed on the surface of the copper foil wire core 100. The fluorine-containing anti-corrosion layer 200 is provided with several grooves arranged parallel to the copper foil wire core 100 to obtain a composite conductor blank.

[0131] S4. The composite conductor blank is passed through a melting furnace containing composite polyethylene coating liquid without drying, and then through a forming hole. After cooling and solidification, an outer protective layer 300 with a thickness of 0.015mm is formed on the surface of the composite conductor blank, resulting in a composite conductor with an insulation layer covering the conductor core.

[0132] Example 8

[0133] Please see the appendix Figure 1-2 This embodiment provides a method for preparing ultrafine copper foil composite wires, including the following steps:

[0134] S1. The fluorine-reinforced modified resin prepared in Example 2 is added to a melting furnace at a temperature of 195°C and heated until the fluorine-reinforced modified resin melts to obtain a fluid fluorine-reinforced modified resin coating liquid.

[0135] S2. The composite polyethylene prepared in Example 5 is added to a melting furnace at a temperature of 195°C and heated until the composite polyethylene melts to obtain a fluid composite polyethylene coating liquid.

[0136] S3. Select copper foil wire with a diameter of 0.03 mm as copper foil wire core 100, heat it to 600℃, keep it at that temperature for 2.5 min, pass it through a melting furnace containing fluorine-enhanced modified resin coating liquid, then pass it through a forming hole, and cool it down with water to solidify it. A fluorine-containing anti-corrosion layer 200 with a thickness of 0.010 mm is formed on the surface of the copper foil wire core 100, and the fluorine-containing anti-corrosion layer 200 is provided with several grooves arranged parallel to the copper foil wire core 100 to obtain a composite conductor blank.

[0137] S4. The composite conductor blank is passed through a melting furnace containing a composite polyethylene coating liquid without drying, and then through a forming hole. After cooling and solidification, an outer protective layer 300 with a thickness of 0.017 mm is formed on the surface of the composite conductor blank, resulting in a composite conductor with an insulation layer covering the conductor core.

[0138] Example 9

[0139] Please see the appendix Figure 1-2 This embodiment provides a method for preparing ultrafine copper foil composite wires, including the following steps:

[0140] S1. The fluorine-reinforced modified resin prepared in Example 3 is added to a melting furnace at a temperature of 200°C and heated until the fluorine-reinforced modified resin melts to obtain a fluid fluorine-reinforced modified resin coating liquid.

[0141] S2. The composite polyethylene prepared in Example 6 is added to a melting furnace at a temperature of 200°C and heated until the composite polyethylene melts to obtain a fluid composite polyethylene coating liquid.

[0142] S3. Select copper foil wire with a diameter of 0.05 mm as copper foil wire core 100, heat it to 700℃, keep it at that temperature for 3 minutes, pass it through a melting furnace containing fluorine-enhanced modified resin coating liquid, then pass it through a forming hole, and cool it down with water to solidify it. A fluorine-containing anti-corrosion layer 200 with a thickness of 0.012 mm is formed on the surface of the copper foil wire core 100, and the fluorine-containing anti-corrosion layer 200 is provided with several grooves arranged parallel to the copper foil wire core 100 to obtain a composite conductor blank.

[0143] S4. The composite conductor blank is passed through a melting furnace containing a composite polyethylene coating liquid without drying, and then through a forming hole. After cooling and solidification, an outer protective layer 300 with a thickness of 0.018 mm is formed on the surface of the composite conductor blank, resulting in a composite conductor with an insulation layer covering the conductor core.

[0144] Comparative Example 1

[0145] The difference between this comparative example and Example 9 is that in Example 3, bisphenol A epoxy resin was not added in step A2 when preparing the fluorinated reinforced resin.

[0146] Comparative Example 2

[0147] The difference between this comparative example and Example 9 is that in Example 6, when preparing the composite polyethylene, no modified polyethylene was added in step B6 when preparing the polyethylene mixture.

[0148] Comparative Example 3

[0149] The difference between this comparative example and Example 9 is that in Example 6, step B5 was omitted when preparing the composite polyethylene, and the modified graphite in step B6 was replaced with the supported expanded graphite in step B3.

[0150] Comparative Example 4

[0151] The difference between this comparative example and Example 9 is that in Example 6, step B3 was omitted when preparing the composite polyethylene, and the expanded graphite in step B2 was used instead of the supported expanded graphite in step B6.

[0152] Performance testing:

[0153] The tensile strength, elongation at break, maximum bending degree, and volume resistivity at 20°C of the composite conductors prepared in Examples 7-9 and Comparative Examples 1-4 were determined in accordance with the standard GB / T 11016.2-2009 "Plastic Insulation and Rubber Insulation Telephone Cords Part 2: Polyvinyl Chloride Insulated Telephone Cords".

[0154] The shielding effectiveness of the composite conductors prepared in Examples 7-9 and Comparative Examples 1-4 was determined in accordance with the standard GB / T 30842-2014 "Requirements and Measurement Methods for Electromagnetic Shielding Effectiveness in High Voltage Laboratories". The specific test results are shown in Table 1 below.

[0155] Table 1 - Performance Test Data of Samples

[0156]

[0157] Data Analysis:

[0158] Comparative analysis of the data in the table above shows that the composite conductor prepared by this invention has a tensile strength of 32.5 MPa, an elongation at break of 375%, a maximum bending radius of 15 mm, a shielding effectiveness of 37.2 dB, and a volume resistivity of 1.71 × 10⁻⁶. 17 The Ω·m values ​​are superior to those of the comparative example, which fully demonstrates that this application improves the mechanical strength and corrosion resistance of the composite conductor by optimizing the material composition of the fluorinated anti-corrosion layer and the outer protective layer, and by the cooperation between the fluorinated anti-corrosion layer and the outer protective layer. At the same time, it also improves the electromagnetic shielding effectiveness and insulation strength of the composite conductor.

[0159] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A composite conductor of ultrafine copper foil wire with a diameter of 0.02 mm to 0.05 mm, comprising a copper foil wire core (100) and an insulating layer covering the copper foil wire core (100), characterized in that, The insulating layer includes a fluorinated anti-corrosion layer (200) and an outer protective layer (300). The fluorinated anti-corrosion layer (200) is obtained by melting and coating a copper foil wire core (100) with a fluorinated reinforced modified resin and then curing it. The outer surface of the fluorinated anti-corrosion layer (200) is provided with a plurality of grooves arranged parallel to the copper foil wire core (100). The outer protective layer (300) is obtained by melting and coating a composite polyethylene layer (200) with a fluorinated anti-corrosion layer (200) and then curing it. The composite polyethylene is composed of 100 parts by weight of polyethylene mixture and 10-15 parts by weight of epoxy resin, wherein the polyethylene mixture is composed of 100 parts by weight of low-density polyethylene, 30-40 parts by weight of modified polyethylene and 12-16 parts by weight of modified graphite. Fluorine-reinforced modified resin is obtained by the following steps: A1. Add butyl acrylate, perfluorooctyl acrylate, vinyl-terminated silicone oil, oleylamine and toluene to a nitrogen-protected reactor and stir. Raise the reactor temperature to 75-85℃, add an initiator to the reactor, keep the reaction at this temperature for 6-8 hours, and then perform post-treatment to obtain a fluorinated resin. A2. Add fluorinated resin and epoxy resin to the reaction vessel and stir. Raise the temperature of the reaction vessel to 190-200℃ and melt and stir for 30-50 minutes to obtain fluorinated reinforced modified resin. Modified polyethylene is obtained by the following steps: B1. After uniformly mixing low-density polyethylene powder, tea polyphenols, glycidyl methacrylate and initiator, add them to a mixer at a temperature of 185-195℃, set the speed of the mixer to 50-60 r / min, and mix for 10-15 min to obtain a mixture. B2. Transfer the mixture to a flat vulcanizing machine. Raise the temperature of the flat vulcanizing machine to 190-200℃ and the pressure to 9-10MPa. Hold the mixture under heat and pressure for 5-10 minutes. The post-processing yields modified polyethylene.

2. The ultrafine copper foil composite conductor with a diameter of 0.02 mm to 0.05 mm according to claim 1, characterized in that, In step A1, the ratio of butyl acrylate, perfluorooctyl acrylate, vinyl-terminated silicone oil, oleylamine, toluene, and initiator is 60-70g:15-18g:10-12g:17-19g:500mL:0.8-1.2g, and the initiator is azobisisobutyronitrile; in step A2, the weight ratio of fluorinated resin and epoxy resin is 7:2-3, and the epoxy resin is bisphenol A type epoxy resin E-51.

3. The ultrafine copper foil composite conductor with a diameter of 0.02 mm to 0.05 mm according to claim 1, characterized in that, In step B1, the weight ratio of the low-density polyethylene powder, tea polyphenols, glycidyl methacrylate, and initiator is 100:1:5-7:0.5, and the initiator is benzoyl peroxide.

4. The ultrafine copper foil composite conductor with a diameter of 0.02 mm to 0.05 mm according to claim 1, characterized in that, Modified graphite is obtained by the following steps: C1. Add flake graphite powder and modifier to the reaction vessel, stir at room temperature for 30-40 minutes, and then perform post-treatment to obtain activated graphite powder; C2. Place the activated graphite powder into a tube furnace under a nitrogen atmosphere, raise the temperature of the tube furnace to 300-350℃, hold for 10-20 minutes, cool down and discharge to obtain expanded graphite. C3. Add expanded graphite, iron pentacarbonyl, and kerosene to a high-pressure reactor under nitrogen protection and stir in a closed manner. Raise the temperature of the high-pressure reactor to 260-280℃ and keep it at that temperature for 90-120 minutes. The post-treatment yields supported expanded graphite. C4. Add supported expanded graphite, modified nano silica, tetraethyl orthosilicate, and anhydrous ethanol to a reaction vessel, ultrasonically disperse for 30-50 min, stir, raise the temperature of the reaction vessel to 50-60℃, add catalyst to the reaction vessel, keep the reaction at this temperature for 60-90 min, and then perform post-treatment to obtain modified graphite.

5. The ultrafine copper foil composite conductor with a diameter of 0.02 mm to 0.05 mm according to claim 4, characterized in that, In step C1, the ratio of flake graphite powder to modifier is 1g:8-12mL, and the modifier is obtained by mixing potassium permanganate and 80-90wt% sulfuric acid at a ratio of 1g:7mL. In step C3, the ratio of expanded graphite, iron pentacarbonyl, and kerosene is 7g:1g:500mL. In step C4, the ratio of supported expanded graphite, modified nano-silica, tetraethyl orthosilicate, anhydrous ethanol, and catalyst is 10g:4g:3g:100mL:10mL, and the catalyst is a 0.3-0.5mol / L sodium hydroxide solution.

6. The ultrafine copper foil composite conductor with a diameter of 0.02 mm to 0.05 mm according to claim 4, characterized in that, Modified nano-silica is obtained by the following steps: D1. Add nano-silica, anhydrous ethanol and 3-aminopropyltriethoxysilane to a reaction vessel and stir. Raise the temperature of the reaction vessel to 50-60℃, add a catalyst to the reaction vessel, keep the temperature for 50-60 min, and then process to obtain activated silica powder. D2. Add activated silica powder and toluene to a nitrogen-protected reactor and stir. At room temperature, add propyltriethoxysilane isocyanate to the reactor and stir for 40-50 minutes. After post-treatment, modified nano silica is obtained.

7. The ultrafine copper foil composite conductor with a diameter of 0.02 mm to 0.05 mm according to claim 6, characterized in that, In step D1, the ratio of nano-silica, anhydrous ethanol, 3-aminopropyltriethoxysilane, and catalyst is 5g:30mL:1g:5mL, and the catalyst is a 0.3-0.5mol / L sodium hydroxide solution; in step D2, the ratio of activated silica powder, toluene, and propyltriethoxysilane isocyanate is 5g:50mL:2g.

8. The ultrafine copper foil composite conductor with a diameter of 0.02 mm to 0.05 mm according to claim 1, characterized in that, The overall outer diameter of the conductor is 0.02mm-0.05mm.

Images