Flexible graphite gasket and method of manufacturing

Abstract

The present application relates to the technical field of grounding material, in particular to a flexible graphite grounding carbon fiber curing material and method, which comprises the following raw materials by weight: carbon fiber matrix 45-55 parts, flake graphite 15-20 parts, oxygen inhibitor 2-4 parts, toughening agent 2-4 parts, adhesive 20-25 parts, additive 4-7 parts, and functional modifier 3-5 parts. The present application takes T700 type carbon fiber as the matrix, which provides strong mechanical support for the material with high tensile strength, and is matched with flake graphite with fixed carbon content of 99%, which greatly improves the electrical conductivity of the material. The synergistic effect of the additive and the functional modifier added simultaneously effectively solves the technical pain points that the traditional material is difficult to balance the electrical conductivity, folding resistance and strength, and the product has remarkable salt mist stability, freezing resistance and temperature change resistance stability.

Description

Technical Field

[0001] This invention relates to the field of grounding materials technology, specifically to a flexible graphite grounding carbon fiber curing material and method. Background Technology

[0002] The grounding systems of 35kV and above substations, wind power, photovoltaic and other new energy sources have put forward stringent requirements on the flexibility, corrosion resistance, high conductivity and mechanical properties of materials. Flexible graphite grounding materials have become the mainstream choice due to their light weight, corrosion resistance and good grounding effect. However, the formulation design of traditional flexible graphite grounding materials is unreasonable, the component synergy is poor and the preparation process lacks specificity, resulting in many technical defects in the materials. It is difficult to balance and coordinate the conductivity, flexural strength and strength of the products, and the products have poor salt spray stability, which limits the efficiency of the products. At the same time, the performance stability of the products is further reduced under freezing and temperature change conditions. Based on this, the present invention provides a carbon fiber curing material and method for flexible graphite grounding. Summary of the Invention

[0003] In view of the deficiencies of the prior art, the purpose of this invention is to provide a carbon fiber curing material and method for flexible graphite grounding, so as to solve the problems mentioned in the background art.

[0004] The present invention solves the technical problem by adopting the following technical solution: This invention provides a flexible graphite grounding carbon fiber cured material, comprising the following raw materials in parts by weight: 45-55 parts carbon fiber matrix, 15-20 parts flake graphite, 2-4 parts antioxidant, 2-4 parts toughening agent, 20-25 parts adhesive, 4-7 parts synergist, and 3-5 parts functional modifier.

[0005] Preferably, the flexible graphite grounding carbon fiber curing material comprises the following raw materials in parts by weight: The composition includes 47.5 parts carbon fiber matrix, 17.5 parts flake graphite, 3 parts antioxidant, 3 parts toughening agent, 22.5 parts adhesive, 5.5 parts synergist, and 4 parts functional modifier.

[0006] Preferably, the carbon fiber matrix is ​​a T700 type carbon fiber bundle with a single filament diameter of 7-10 μm and a tensile strength ≥4900 MPa; The antioxidant is diphenylisodecyl phosphite; the toughening agent is carboxyl-terminated butadiene-acrylonitrile rubber with a number average molecular weight of 3000-5000. Flake graphite has a fixed carbon content of ≥99% and a particle size of 200-300 mesh; The adhesive is prepared by mixing 20-30 parts of phenolic resin, 20-25 parts of epoxy resin E-51, 2-4 parts of silane coupling agent KH-550, 8-12 parts of anhydrous ethanol, and 1-3 parts of dibutyl phthalate according to the weight ratio. The mixing temperature is 65℃, the mixing speed is 1000-1500 r / min, and the mixing time is 30 min to obtain the adhesive.

[0007] Preferably, the preparation method of the additive is as follows: S11: Stir carbon nanotubes thoroughly in a sufficient amount of sulfuric acid solution with a mass fraction of 20-30%, then wash with water, filter, and dry; mix 5-8 parts of dried carbon nanotubes, 2-4 parts of nano lanthanum oxide, 7-11 parts of sodium lignosulfonate solution with a mass fraction of 5-8%, and 2-3 parts of nano silica sol thoroughly to obtain carbon nanotube solution. S12: Heat-treat montmorillonite at 110-120℃ for 10-15 min, then raise the temperature to 300-320℃ at a rate of 3-5℃ / min, hold for 35-45 min, then cool to 60℃ at a rate of 5-8℃ / min, and hold to obtain heat-treated montmorillonite. Mix 3-5 parts of wollastonite, 2-4 parts of nano-titanium oxide and 1-3 parts of 2-5% yttrium nitrate solution and add them to 4-7 parts of 5-8% sodium citrate solution and stir until homogeneous to obtain wollastonite solution. S13: Mix the heat-treated montmorillonite and wollastonite liquid in a weight ratio of (5-7):3 and ball mill them at a speed of 1000-1500 r / min for 2 hours. After ball milling, filter and dry to obtain montmorillonite-wollastonite modifier. S14: The montmorillonite-wollastonite modifier and carbon nanotube liquid are ultrasonically treated at a weight ratio of 3:(5-7), with an ultrasonic power of 350-400W for 1 hour. After ultrasonic treatment, the mixture is filtered and dried to obtain the modifier.

[0008] Preferably, the wollastonite is acicular wollastonite with a particle size of 1-3 μm; the nano-titanium dioxide is anatase type with a particle size of 20-50 nm.

[0009] Preferably, the montmorillonite is sodium-based montmorillonite with a particle size of 2-3 μm; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-15 nm and a length of 6-8 μm.

[0010] Preferably, the preparation method of the functional modifier is as follows: S101: 5-8 parts of sheet graphene, 3-5 parts of nickel oxide and 2-3 parts of neodymium powder are blended and sintered for 1 hour at a sintering temperature of 350-370℃. After sintering, a sintered graphene body is obtained. S102: Mix 3-5 parts of β-cyclodextrin, 2-4 parts of sodium dodecylbenzenesulfonate solution (8% by mass), 2-4 parts of graphene sintered body, and 5-8 parts of chitosan solution (2-5% by mass) evenly to obtain a functional blending liquid. S103: The whisker support agent and functional blending liquid are ball-milled at a weight ratio of (8-10):5, with a ball milling speed of 1000-1500 r / min for 2 hours. After ball milling, the mixture is filtered and dried to obtain the functional modifier.

[0011] Preferably, the preparation method of the whisker support agent is as follows: S103a: Preheat aluminum borate whiskers at 135-145℃ for 1 hour to obtain preheated aluminum borate whiskers. Mix the preheated aluminum borate whiskers, sodium silicate solution with a mass fraction of 2-5% and glass microspheres in a weight ratio of (3-5):7:(1-2) to obtain whisker solution. S103b: Mix 3-5 parts of nano-zirconia, 2-4 parts of sodium alginate powder and 4-6 parts of nano-silicon carbide evenly to obtain the additive; The whisker solution and additives were mixed at a weight ratio of (7-9):4 and ball-milled at a speed of 1500-1600 r / min for 2 hours. After the ball milling was completed, the mixture was filtered and dried to obtain the whisker support agent.

[0012] Preferably, the aluminum borate whiskers have a particle size of 5-10 μm and an aspect ratio of 20-50:1; the glass microspheres have a density of 0.8-1.2 g / cm³. 3 The particle size is 10-50 μm; the particle size of nano-zirconia and nano-silicon carbide is 20-30 nm; the particle size of sheet graphene is 2-5 μm, the thickness is 1-5 nm, the number of layers is 4-6, and the specific surface area is 300-800 m². 2 / g.

[0013] This invention also provides a method for preparing a carbon fiber cured material for flexible graphite grounding, comprising the following steps: Step 1: Dry the carbon fiber matrix to a moisture content of ≤0.5%. After high-temperature calcination to remove impurities, the flake graphite is mixed with adhesive, additive, functional modifier, antioxidant and toughening agent and ultrasonically dispersed for 20-30 minutes at an ultrasonic power of 500-550W to obtain a cured slurry. Step 2: Carbon fiber weaving and impregnation. The carbon fiber matrix from Step 1 is plain-woven into a woven tape with a weaving density of 20-30 strands / cm and a fiber tension of 5-8N. The woven tape is then immersed in a curing slurry for 10-15 minutes to ensure uniform adhesive coating on the surface of the carbon fiber woven tape. After draining off excess slurry, a prepreg tape is obtained. Step 3: Gradient curing molding. The prepreg tape is placed in an inert gas protective atmosphere for gradient curing to obtain the initial cured material. The material is first heated to 100-110℃ for 15 minutes in a preheating section, then heated to 200-220℃ for 35 minutes in a curing section, with a pressure of 0.3-0.8MPa applied during the curing process. Finally, it is cooled to 30-40℃ in a cooling section at a rate of 5-7℃ / min to obtain the initial cured material. Step 4: Post-flexibility treatment. The pre-cured material is ultrasonically cleaned at 300-350W for 5-10 minutes to remove residual slurry impurities on the surface. Then, it is subjected to low-temperature stretching and flexibility treatment at a stretching rate of 2-3 mm / min to eliminate residual stress inside the material, thus obtaining the flexible graphite grounding carbon fiber cured material of the present invention.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses T700 carbon fiber as the matrix, whose high tensile strength provides solid mechanical support for the material. Combined with flake graphite with a fixed carbon content of ≥99%, the conductivity of the material is greatly improved. At the same time, the synergistic effect of the added additives and functional modifiers effectively solves the technical pain point of traditional materials that it is difficult to balance conductivity, flexural strength and strength. In addition, the product has significant effects on salt spray resistance, freeze resistance and temperature change resistance. 2. Carbon nanotubes are improved by acidification and activation with sulfuric acid solution. Then, a carbon nanotube liquid is prepared by blending and coordinating nano-lanthanum oxide, sodium lignosulfonate solution, and nano-silica sol to form an excellent conductive environment. At the same time, montmorillonite-wollastonite modifier is added to enhance the conductivity, flexural strength, and overall strength of the product system, while optimizing the product's performance stability. After high-temperature gradient heat treatment, the layered structure of montmorillonite is more stable. It is then blended and combined with nano-titanium oxide and wollastonite structures, which are interspersed in the system to further enhance the system's performance stability and optimize the product's salt spray resistance, freeze resistance, and temperature change resistance. 3. After preheating at 135-145℃, aluminum borate whiskers enhance their activity. Their excellent aspect ratio effectively strengthens the mechanical support properties of the loading agent. Combined with glass microspheres and sodium silicate solution, they further enhance the loading sites and improve the product's functionality. The additives formed by the compounding of nano-zirconia, nano-silicon carbide, and sodium alginate powder significantly strengthen the temperature resistance and corrosion resistance of the whisker loading agent. After the whisker liquid and additives are thoroughly mixed by high-speed ball milling, a uniform and dense composite structure is formed. This structure can serve as the core carrier for functional modifiers, efficiently loading functional components such as graphene sintered bodies, ensuring uniform dispersion and full utilization of functional components. It can also further improve the tensile strength, crack resistance, and dimensional stability of the cured material, while also helping to optimize the material's conductivity. In synergy with the additives, it further achieves a comprehensive balance of conductivity, flexibility, mechanical properties, and environmental stability of the cured material, making it suitable for the stringent requirements of 35kV and above substations, wind power, photovoltaic, and other new energy grounding systems. 4. The graphene sintered body in the functional blending liquid is made by sintering graphene with nickel oxide and neodymium powder. By blending the raw materials, the functionality of the product is enhanced and the performance coordination of the product is optimized. Through the mutual combination of raw materials, the product performance is further improved. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. 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.

[0016] This embodiment of a flexible graphite grounding carbon fiber curing material comprises the following raw materials in parts by weight: 45-55 parts carbon fiber matrix, 15-20 parts flake graphite, 2-4 parts antioxidant, 2-4 parts toughening agent, 20-25 parts adhesive, 4-7 parts synergist, and 3-5 parts functional modifier.

[0017] The flexible graphite grounding carbon fiber curing material of this embodiment includes the following raw materials in parts by weight: The composition includes 47.5 parts carbon fiber matrix, 17.5 parts flake graphite, 3 parts antioxidant, 3 parts toughening agent, 22.5 parts adhesive, 5.5 parts synergist, and 4 parts functional modifier.

[0018] The carbon fiber matrix in this embodiment is T700 type carbon fiber bundle, with a single filament diameter of 7-10μm and a tensile strength ≥4900MPa; The antioxidant is diphenylisodecyl phosphite; the toughening agent is carboxyl-terminated butadiene-acrylonitrile rubber with a number average molecular weight of 3000-5000. Flake graphite has a fixed carbon content of ≥99% and a particle size of 200-300 mesh; The adhesive is prepared by mixing 20-30 parts of phenolic resin, 20-25 parts of epoxy resin E-51, 2-4 parts of silane coupling agent KH-550, 8-12 parts of anhydrous ethanol, and 1-3 parts of dibutyl phthalate according to the weight ratio. The mixing temperature is 65℃, the mixing speed is 1000-1500 r / min, and the mixing time is 30 min to obtain the adhesive.

[0019] The preparation method of the additive in this embodiment is as follows: S11: Stir carbon nanotubes thoroughly in a sufficient amount of sulfuric acid solution with a mass fraction of 20-30%, then wash with water, filter, and dry; mix 5-8 parts of dried carbon nanotubes, 2-4 parts of nano lanthanum oxide, 7-11 parts of sodium lignosulfonate solution with a mass fraction of 5-8%, and 2-3 parts of nano silica sol thoroughly to obtain carbon nanotube solution. S12: Heat-treat montmorillonite at 110-120℃ for 10-15 min, then raise the temperature to 300-320℃ at a rate of 3-5℃ / min, hold for 35-45 min, then cool to 60℃ at a rate of 5-8℃ / min, and hold to obtain heat-treated montmorillonite. Mix 3-5 parts of wollastonite, 2-4 parts of nano-titanium oxide and 1-3 parts of 2-5% yttrium nitrate solution and add them to 4-7 parts of 5-8% sodium citrate solution and stir until homogeneous to obtain wollastonite solution. S13: Mix the heat-treated montmorillonite and wollastonite liquid in a weight ratio of (5-7):3 and ball mill them at a speed of 1000-1500 r / min for 2 hours. After ball milling, filter and dry to obtain montmorillonite-wollastonite modifier. S14: The montmorillonite-wollastonite modifier and carbon nanotube liquid are ultrasonically treated at a weight ratio of 3:(5-7), with an ultrasonic power of 350-400W for 1 hour. After ultrasonic treatment, the mixture is filtered and dried to obtain the modifier.

[0020] In this embodiment, the wollastonite is acicular wollastonite with a particle size of 1-3 μm; the nano-titanium dioxide is anatase type with a particle size of 20-50 nm.

[0021] In this embodiment, the montmorillonite is sodium-based montmorillonite with a particle size of 2-3 μm; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-15 nm and a length of 6-8 μm.

[0022] The preparation method of the functional modifier in this embodiment is as follows: S101: 5-8 parts of sheet graphene, 3-5 parts of nickel oxide and 2-3 parts of neodymium powder are blended and sintered for 1 hour at a sintering temperature of 350-370℃. After sintering, a sintered graphene body is obtained. S102: Mix 3-5 parts of β-cyclodextrin, 2-4 parts of sodium dodecylbenzenesulfonate solution (8% by mass), 2-4 parts of graphene sintered body, and 5-8 parts of chitosan solution (2-5% by mass) evenly to obtain a functional blending liquid. S103: The whisker support agent and functional blending liquid are ball-milled at a weight ratio of (8-10):5, with a ball milling speed of 1000-1500 r / min for 2 hours. After ball milling, the mixture is filtered and dried to obtain the functional modifier.

[0023] The preparation method of the whisker support agent in this embodiment is as follows: S103a: Preheat aluminum borate whiskers at 135-145℃ for 1 hour to obtain preheated aluminum borate whiskers. Mix the preheated aluminum borate whiskers, sodium silicate solution with a mass fraction of 2-5% and glass microspheres in a weight ratio of (3-5):7:(1-2) to obtain whisker solution. S103b: Mix 3-5 parts of nano-zirconia, 2-4 parts of sodium alginate powder and 4-6 parts of nano-silicon carbide evenly to obtain the additive; The whisker solution and additives were mixed at a weight ratio of (7-9):4 and ball-milled at a speed of 1500-1600 r / min for 2 hours. After the ball milling was completed, the mixture was filtered and dried to obtain the whisker support agent.

[0024] In this embodiment, the aluminum borate whiskers have a particle size of 5-10 μm and an aspect ratio of 20-50:1; the glass microspheres have a density of 0.8-1.2 g / cm³. 3 The particle size is 10-50 μm; the particle size of nano-zirconia and nano-silicon carbide is 20-30 nm; the particle size of sheet graphene is 2-5 μm, the thickness is 1-5 nm, the number of layers is 4-6, and the specific surface area is 300-800 m². 2 / g.

[0025] This embodiment describes a method for preparing a flexible graphite grounding carbon fiber cured material, comprising the following steps: Step 1: Dry the carbon fiber matrix to a moisture content of ≤0.5%. After high-temperature calcination to remove impurities, the flake graphite is mixed with adhesive, additive, functional modifier, antioxidant and toughening agent and ultrasonically dispersed for 20-30 minutes at an ultrasonic power of 500-550W to obtain a cured slurry. Step 2: Carbon fiber weaving and impregnation. The carbon fiber matrix from Step 1 is plain-woven into a woven tape with a weaving density of 20-30 strands / cm and a fiber tension of 5-8N. The woven tape is then immersed in a curing slurry for 10-15 minutes to ensure uniform adhesive coating on the surface of the carbon fiber woven tape. After draining off excess slurry, a prepreg tape is obtained. Step 3: Gradient curing molding. The prepreg tape is placed in an inert gas protective atmosphere for gradient curing to obtain the initial cured material. The material is first heated to 100-110℃ for 15 minutes in a preheating section, then heated to 200-220℃ for 35 minutes in a curing section, with a pressure of 0.3-0.8MPa applied during the curing process. Finally, it is cooled to 30-40℃ in a cooling section at a rate of 5-7℃ / min to obtain the initial cured material. Step 4: Post-flexibility treatment. The pre-cured material is ultrasonically cleaned at 300-350W for 5-10 minutes to remove residual slurry impurities on the surface. Then, it is subjected to low-temperature stretching and flexibility treatment at a stretching rate of 2-3 mm / min to eliminate residual stress inside the material, thus obtaining the flexible graphite grounding carbon fiber cured material of the present invention.

[0026] Example 1. This embodiment of a flexible graphite grounding carbon fiber curing material comprises the following raw materials in parts by weight: The composition includes 45 parts carbon fiber matrix, 15 parts flake graphite, 2 parts antioxidant, 2 parts toughening agent, 20 parts adhesive, 4 parts enhancer, and 3 parts functional modifier.

[0027] The carbon fiber matrix in this embodiment is T700 type carbon fiber bundle with a single filament diameter of 7μm and a tensile strength ≥4900MPa; The antioxidant is diphenylisodecyl phosphite; the toughening agent is carboxyl-terminated butadiene-acrylonitrile rubber with a number average molecular weight of 3000. Flake graphite has a fixed carbon content of ≥99% and a particle size of 200 mesh; The adhesive is prepared by mixing 20 parts of phenolic resin, 20 parts of epoxy resin E-51, 2 parts of silane coupling agent KH-550, 8 parts of anhydrous ethanol, and 1 part of dibutyl phthalate according to the weight ratio. The mixing temperature is 65℃, the mixing speed is 1000r / min, and the mixing time is 30min to obtain the adhesive.

[0028] The preparation method of the additive in this embodiment is as follows: S11: Stir the carbon nanotubes thoroughly in a sufficient amount of 20% sulfuric acid solution, then wash with water, filter and dry; mix 5 parts of dried carbon nanotubes, 2 parts of nano lanthanum oxide, 7 parts of 5% sodium lignosulfonate solution and 2 parts of nano silica sol thoroughly to obtain carbon nanotube liquid. S12: The montmorillonite was heat-treated at 110℃ for 10 min, then heated to 300℃ at a rate of 3℃ / min and held for 35 min, and then cooled to 60℃ at a rate of 5℃ / min and held to obtain the heat-treated montmorillonite. Three parts of wollastonite, two parts of nano-titanium oxide, and one part of 2% yttrium nitrate solution were mixed and added to four parts of 5% sodium citrate solution and stirred until homogeneous to obtain wollastonite solution. S13: Heat-treated montmorillonite and wollastonite liquid were mixed at a weight ratio of 5:3 and ball-milled at a speed of 1000 r / min for 2 hours. After ball milling, the mixture was filtered and dried to obtain montmorillonite-wollastonite modifier. S14: The montmorillonite-wollastonite modifier and carbon nanotube liquid were ultrasonically treated at a weight ratio of 3:5. The ultrasonic power was 350W and the ultrasonic treatment lasted for 1 hour. After ultrasonic treatment, the mixture was filtered and dried to obtain the modifier.

[0029] In this embodiment, the wollastonite is acicular wollastonite with a particle size of 1 μm; the nano-titanium dioxide is anatase type with a particle size of 20 nm.

[0030] In this embodiment, the montmorillonite is sodium-based montmorillonite with a particle size of 2 μm; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10 nm and a length of 6 μm.

[0031] The preparation method of the functional modifier in this embodiment is as follows: S101: 5 parts of sheet graphene, 3 parts of nickel oxide and 2 parts of neodymium powder are mixed and sintered for 1 hour at a sintering temperature of 350℃. After sintering, a sintered graphene body is obtained. S102: Mix 3 parts of β-cyclodextrin, 2 parts of sodium dodecylbenzenesulfonate solution (8% by mass), 2 parts of graphene sintered body, and 5 parts of chitosan solution (2% by mass) evenly to obtain a functional blending liquid. S103: The whisker support agent and the functional blending liquid were ball-milled at a weight ratio of 8:5 at a speed of 1000 r / min for 2 hours. After the ball milling was completed, the mixture was filtered and dried to obtain the functional modifier.

[0032] The preparation method of the whisker support agent in this embodiment is as follows: S103a: Preheat aluminum borate whiskers at 135℃ for 1 hour to obtain preheated aluminum borate whiskers. Mix the preheated aluminum borate whiskers, 2% sodium silicate solution and glass microspheres at a weight ratio of 3:7:1 to obtain whisker solution. S103b: 3 parts nano zirconium oxide, 2 parts sodium alginate powder and 4 parts nano silicon carbide are mixed evenly to obtain the additive; The whisker solution and additives were mixed at a weight ratio of 7:4 and ball-milled at a speed of 1500 r / min for 2 hours. After ball milling, the mixture was filtered and dried to obtain the whisker support agent.

[0033] The aluminum borate whiskers in this embodiment have a particle size of 5 μm and an aspect ratio of 20:1; the glass microspheres have a density of 0.8 g / cm³. 3 The particle size is 10 μm; the particle size of nano-zirconia and nano-silicon carbide is 20 nm; the sheet-like graphene has a sheet diameter of 2 μm, a thickness of 1 nm, 4 layers, and a specific surface area of ​​300 m². 2 / g.

[0034] This embodiment describes a method for preparing a flexible graphite grounding carbon fiber cured material, comprising the following steps: Step 1: Dry the carbon fiber matrix to a moisture content of ≤0.5%. After high-temperature calcination to remove impurities, the flake graphite is mixed with adhesive, additive, functional modifier, antioxidant and toughening agent and ultrasonically dispersed for 20 minutes at an ultrasonic power of 500W to obtain a cured slurry. Step 2: Carbon fiber weaving and impregnation. The carbon fiber matrix from Step 1 is plain-woven into a woven tape with a weaving density of 20 strands / cm and a fiber tension of 5N. The woven tape is then immersed in the curing slurry for 10 minutes to ensure uniform adhesive coating on the surface of the carbon fiber woven tape. After draining off excess slurry, a prepreg tape is obtained. Step 3: Gradient curing molding. The prepreg tape is placed in an inert gas protective atmosphere for gradient curing to obtain the initial cured material. The material is first heated to 100℃ for 15 minutes in a preheating section, then heated to 200℃ for 35 minutes in a curing section, with a pressure of 0.3MPa applied during the curing process. Finally, it is cooled to 30℃ in a cooling section at a cooling rate of 5℃ / min to obtain the initial cured material. Step 4: Post-flexibility treatment. The pre-cured material is ultrasonically cleaned with 300W for 5 minutes to remove residual slurry impurities on the surface. Then, it is subjected to low-temperature stretching and flexibility treatment at a stretching rate of 2mm / min to eliminate residual stress inside the material, thus obtaining the flexible graphite grounding carbon fiber curing material of the present invention.

[0035] Example 2. This embodiment of a flexible graphite grounding carbon fiber curing material comprises the following raw materials in parts by weight: The composition includes 55 parts carbon fiber matrix, 20 parts flake graphite, 4 parts antioxidant, 4 parts toughening agent, 25 parts adhesive, 7 parts enhancer, and 5 parts functional modifier.

[0036] The carbon fiber matrix in this embodiment is T700 type carbon fiber bundle with a single filament diameter of 10μm and a tensile strength ≥4900MPa; The antioxidant is diphenylisodecyl phosphite; the toughening agent is carboxyl-terminated butadiene-acrylonitrile rubber with a number average molecular weight of 5000. Flake graphite has a fixed carbon content of ≥99% and a particle size of 300 mesh; The adhesive is prepared by mixing 30 parts of phenolic resin, 25 parts of epoxy resin E-51, 4 parts of silane coupling agent KH-550, 12 parts of anhydrous ethanol, and 3 parts of dibutyl phthalate according to the weight ratio. The mixing temperature is 65℃, the mixing speed is 1500 r / min, and the mixing time is 30 min to obtain the adhesive.

[0037] The preparation method of the additive in this embodiment is as follows: S11: Stir the carbon nanotubes thoroughly in a sufficient amount of 30% sulfuric acid solution, then wash with water, filter and dry; mix 8 parts of dried carbon nanotubes, 4 parts of nano lanthanum oxide, 11 parts of 8% sodium lignosulfonate solution and 3 parts of nano silica sol thoroughly to obtain carbon nanotube liquid. S12: The montmorillonite was heat-treated at 120℃ for 15 min, then heated to 320℃ at a rate of 5℃ / min and held for 45 min, and then cooled to 60℃ at a rate of 8℃ / min and held to obtain the heat-treated montmorillonite. Five parts of wollastonite, four parts of nano-titanium oxide and three parts of 5% yttrium nitrate solution were mixed and added to seven parts of 8% sodium citrate solution and stirred evenly to obtain wollastonite solution. S13: Heat-treated montmorillonite and wollastonite liquid were mixed at a weight ratio of 7:3 and ball-milled at a speed of 1500 r / min for 2 hours. After ball milling, the mixture was filtered and dried to obtain montmorillonite-wollastonite modifier. S14: The montmorillonite-wollastonite modifier and carbon nanotube liquid were ultrasonically treated at a weight ratio of 3:7. The ultrasonic power was 400W and the ultrasonic treatment lasted for 1 hour. After ultrasonic treatment, the mixture was filtered and dried to obtain the modifier.

[0038] In this embodiment, the wollastonite is acicular wollastonite with a particle size of 3 μm; the nano-titanium dioxide is anatase type with a particle size of 50 nm.

[0039] In this embodiment, the montmorillonite is sodium-based montmorillonite with a particle size of 3 μm; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 15 nm and a length of 8 μm.

[0040] The preparation method of the functional modifier in this embodiment is as follows: S101: 8 parts of sheet graphene, 5 parts of nickel oxide and 3 parts of neodymium powder are mixed and sintered for 1 hour at a sintering temperature of 370℃. After sintering, a sintered graphene body is obtained. S102: Mix 5 parts of β-cyclodextrin, 4 parts of sodium dodecylbenzenesulfonate solution with a mass fraction of 8%, 4 parts of graphene sintered body and 8 parts of chitosan solution with a mass fraction of 5% evenly to obtain a functional blending liquid. S103: The whisker support agent and the functional blending liquid were ball-milled at a weight ratio of 10:5 at a speed of 1500 r / min for 2 hours. After the ball milling was completed, the mixture was filtered and dried to obtain the functional modifier.

[0041] The preparation method of the whisker support agent in this embodiment is as follows: S103a: Preheat aluminum borate whiskers at 145℃ for 1 hour to obtain preheated aluminum borate whiskers. Mix the preheated aluminum borate whiskers, 5% sodium silicate solution and glass microspheres at a weight ratio of 5:7:2 to obtain whisker solution. S103b: 5 parts of nano-zirconia, 4 parts of sodium alginate powder and 6 parts of nano-silicon carbide are mixed evenly to obtain the additive; The whisker solution and additives were mixed at a weight ratio of 9:4 and ball-milled at a speed of 1600 r / min for 2 hours. After ball milling, the mixture was filtered and dried to obtain the whisker support agent.

[0042] The aluminum borate whiskers in this embodiment have a particle size of 10 μm and an aspect ratio of 50:1; the glass microspheres have a density of 1.2 g / cm³. 3 The particle size is 50 μm; the particle size of nano-zirconia and nano-silicon carbide is 30 nm; the sheet-like graphene has a sheet diameter of 5 μm, a thickness of 5 nm, 6 layers, and a specific surface area of ​​800 m². 2 / g.

[0043] This embodiment describes a method for preparing a flexible graphite grounding carbon fiber cured material, comprising the following steps: Step 1: Dry the carbon fiber matrix to a moisture content of ≤0.5%. After high-temperature calcination to remove impurities, the flake graphite is mixed with adhesive, additive, functional modifier, antioxidant and toughening agent and ultrasonically dispersed for 20-30 minutes at an ultrasonic power of 500-550W to obtain a cured slurry. Step 2: Carbon fiber weaving and impregnation. The carbon fiber matrix from Step 1 is plain-woven into a woven tape with a weaving density of 30 strands / cm and a fiber tension of 8N. The woven tape is then immersed in the curing slurry for 15 minutes to ensure that the carbon fiber woven tape is evenly coated with slurry. After draining off the excess slurry, a prepreg tape is obtained. Step 3: Gradient curing molding. The prepreg tape is placed in an inert gas protective atmosphere for gradient curing to obtain the initial cured material. The material is first heated to 110℃ for 15 minutes in a preheating section and then heated to 220℃ for 35 minutes in a curing section. During the curing process, a pressure of 0.8MPa is applied. Finally, the material is cooled to 40℃ in a cooling section at a rate of 7℃ / min to obtain the initial cured material. Step 4: Post-flexibility treatment. The pre-cured material is ultrasonically cleaned with 350W for 10 minutes to remove residual slurry impurities on the surface. Then, it is subjected to low-temperature stretching and flexibility treatment at a stretching rate of 3mm / min to eliminate residual stress inside the material, thus obtaining the flexible graphite grounding carbon fiber curing material of the present invention.

[0044] Example 3. This embodiment of a flexible graphite grounding carbon fiber curing material comprises the following raw materials in parts by weight: The composition includes 50 parts carbon fiber matrix, 17.5 parts flake graphite, 3 parts antioxidant, 3 parts toughening agent, 22.5 parts adhesive, 5.5 parts synergist, and 4 parts functional modifier.

[0045] In this embodiment, the carbon fiber matrix is ​​a T700 type carbon fiber bundle with a single filament diameter of 8.5μm and a tensile strength ≥4900MPa; The antioxidant is diphenylisodecyl phosphite; the toughening agent is carboxyl-terminated butadiene-acrylonitrile rubber with a number average molecular weight of 4000. Flake graphite has a fixed carbon content of ≥99% and a particle size of 200 mesh; The adhesive is prepared by mixing 25 parts of phenolic resin, 22.5 parts of epoxy resin E-51, 3 parts of silane coupling agent KH-550, 10 parts of anhydrous ethanol, and 2 parts of dibutyl phthalate according to the weight ratio. The mixing temperature is 65℃, the mixing speed is 1250 r / min, and the mixing time is 30 min to obtain the adhesive.

[0046] The preparation method of the additive in this embodiment is as follows: S11: Stir the carbon nanotubes thoroughly in a sufficient amount of 25% sulfuric acid solution, then wash with water, filter and dry; mix 6.5 parts of dried carbon nanotubes, 3 parts of nano lanthanum oxide, 9 parts of 6.5% sodium lignosulfonate solution and 2.5 parts of nano silica sol thoroughly to obtain carbon nanotube liquid. S12: Montmorillonite was heat-treated at 115℃ for 12.5 min, then heated to 310℃ at a rate of 4℃ / min and held for 40 min, then cooled to 60℃ at a rate of 6.5℃ / min and held to obtain heat-treated montmorillonite. Four parts of wollastonite, three parts of nano-titanium oxide, and two parts of 3.5% yttrium nitrate solution were mixed and added to 5.5 parts of 6.5% sodium citrate solution and stirred until homogeneous to obtain wollastonite solution. S13: Heat-treated montmorillonite and wollastonite liquid were mixed at a weight ratio of 6:3 and ball-milled at a speed of 1250 r / min for 2 h. After ball milling, the mixture was filtered and dried to obtain montmorillonite-wollastonite modifier. S14: The montmorillonite-wollastonite modifier and carbon nanotube liquid were ultrasonically treated at a weight ratio of 3:6. The ultrasonic power was 370W, and the ultrasonic treatment lasted for 1 hour. After ultrasonic treatment, the mixture was filtered and dried to obtain the modifier.

[0047] In this embodiment, the wollastonite is acicular wollastonite with a particle size of 2 μm; the nano-titanium dioxide is anatase type with a particle size of 25 nm.

[0048] In this embodiment, the montmorillonite is sodium-based montmorillonite with a particle size of 2.5 μm; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 12.5 nm and a length of 7 μm.

[0049] The preparation method of the functional modifier in this embodiment is as follows: S101: 6.5 parts of sheet graphene, 4 parts of nickel oxide and 2.5 parts of neodymium powder were mixed and sintered for 1 hour at a sintering temperature of 360℃. After sintering, a sintered graphene body was obtained. S102: Mix 4 parts of β-cyclodextrin, 3 parts of sodium dodecylbenzenesulfonate solution with a mass fraction of 8%, 3 parts of graphene sintered body and 6.5 parts of chitosan solution with a mass fraction of 3.5% evenly to obtain a functional blending liquid; S103: The whisker support agent and the functional blending liquid were ball-milled at a weight ratio of 9:5 at a speed of 1250 r / min for 2 hours. After the ball milling was completed, the mixture was filtered and dried to obtain the functional modifier.

[0050] The preparation method of the whisker support agent in this embodiment is as follows: S103a: Preheat aluminum borate whiskers at 140℃ for 1 hour to obtain preheated aluminum borate whiskers. Mix the preheated aluminum borate whiskers, sodium silicate solution with a mass fraction of 2-5% and glass microspheres at a weight ratio of 4:7:1.5 to obtain whisker solution. S103b: 4 parts of nano-zirconia, 3 parts of sodium alginate powder and 5 parts of nano-silicon carbide are mixed evenly to obtain the additive; The whisker solution and additives were mixed at a weight ratio of 8:4 and ball-milled at a speed of 1550 r / min for 2 hours. After ball milling, the mixture was filtered and dried to obtain the whisker support agent.

[0051] The aluminum borate whiskers in this embodiment have a particle size of 7.5 μm and an aspect ratio of 35:1; the density of the glass microspheres is 1.0 g / cm³. 3 The particle size is 30 μm; the particle size of nano-zirconia and nano-silicon carbide is 25 nm; the sheet-like graphene has a sheet size of 3.5 μm, a thickness of 3 nm, 5 layers, and a specific surface area of ​​500 m².2 / g.

[0052] This embodiment describes a method for preparing a flexible graphite grounding carbon fiber cured material, comprising the following steps: Step 1: Dry the carbon fiber matrix to a moisture content of ≤0.5%. After high-temperature calcination to remove impurities, the flake graphite is mixed with adhesive, additive, functional modifier, antioxidant and toughening agent and ultrasonically dispersed for 25 minutes at an ultrasonic power of 525W to obtain a cured slurry. Step 2: Carbon fiber weaving and impregnation. The carbon fiber matrix from Step 1 is plain-woven into a woven tape with a weaving density of 25 strands / cm and a fiber tension of 6.5N. The woven tape is then immersed in the curing slurry for 12 minutes to ensure uniform adhesive coating on the surface of the carbon fiber woven tape. After draining off excess slurry, a prepreg tape is obtained. Step 3: Gradient curing molding. The prepreg tape is placed in an inert gas protective atmosphere for gradient curing to obtain the initial cured material. The material is first heated to 105℃ for 15 minutes in a preheating section, then heated to 210℃ for 35 minutes in a curing section, with a pressure of 0.5MPa applied during the curing process. Finally, it is cooled to 35℃ in a cooling section at a rate of 6℃ / min to obtain the initial cured material. Step 4: Post-flexibility treatment. The pre-cured material is ultrasonically cleaned at 325W for 7.5 minutes to remove residual slurry impurities on the surface. Then, it is subjected to low-temperature stretching and flexibility treatment at a stretching rate of 2.5mm / min to eliminate residual stress inside the material, thus obtaining the flexible graphite grounding carbon fiber cured material of the present invention.

[0053] Comparative Example 1. Unlike Example 3, no additives were added.

[0054] Comparative Example 2. Unlike Example 3, the montmorillonite-wollastonite modifier was not used in the preparation of the modifier.

[0055] Comparative Example 3. Unlike Example 3, no heat-treated montmorillonite was added in the preparation of the montmorillonite-wollastonite modifier.

[0056] Comparative Example 4. Unlike Example 3, no wollastonite or nano-titanium oxide was added to the wollastonite liquid.

[0057] Comparative Example 5. Unlike Example 3, carbon nanotube liquid treatment was not used in the preparation of the additive.

[0058] Comparative Example 6. Unlike Example 3, no functional modifier was added.

[0059] Comparative Example 7. Unlike Example 3, no functional blending liquid was added in the preparation method of the functional modifier.

[0060] Comparative Example 8. Unlike Example 3, no graphene sintered body was added to the functional blending liquid.

[0061] Comparative Example 9. Unlike Example 3, nickel oxide and neodymium powder were not added in the preparation method of the graphene sintered body.

[0062] Comparative Example 10. Unlike Example 3, the preparation method of the functional modifier did not include a whisker support agent.

[0063] Comparative Example 11. Unlike Example 3, no additives were added during the preparation of the whisker support agent.

[0064] Comparative Example 12. Unlike Example 3, nano-zirconia and nano-silicon carbide were not added during the preparation of the additive.

[0065] Comparative Example 13. Unlike Example 3, whisker solution was not added during the preparation of the whisker support agent.

[0066] The conductivity, flexural strength, and strength of the products from Examples 1-3 and Comparative Examples 1-13 were tested, as well as their salt spray resistance, freeze resistance, and temperature change stability (the products were placed at -10℃ for 12 hours, then at 50℃ for 12 hours, and finally at 75℃ for 12 hours, which constituted one cycle, and the cycle was repeated 10 times). The test results are as follows. As can be seen from Comparative Examples 1-13 and Examples 1-3; The product in Example 3 has excellent conductivity, flexural strength, and performance coordination. It also exhibits significant resistance to salt spray, freezing, and temperature changes. Without the addition of either the additive or the functional modifier, the product's performance deteriorates significantly, especially in terms of freeze resistance and temperature change stability. By using the synergistic combination of the additive and the functional modifier, the product's performance is significantly enhanced. In the preparation of the additive, the montmorillonite-wollastonite modifier was not used for treatment; in the preparation of the montmorillonite-wollastonite modifier, heat-treated montmorillonite was not added; wollastonite and nano-titanium oxide were not added to the wollastonite liquid; and carbon nanotube liquid treatment was not used in the preparation of the additive. The performance of the products tended to deteriorate. The additives prepared by different methods showed the most significant performance effects. The preparation methods of functional modifiers do not include functional blending liquid, nor do they include graphene sintered body. Furthermore, the preparation methods of graphene sintered body do not include nickel oxide and neodymium powder. The preparation methods of functional modifiers do not include whisker support agents, nor do they include additives. The preparation methods of additives do not include nano-zirconia and nano-silicon carbide, nor do they include whisker liquid. All of these methods tend to deteriorate the performance of the products. Therefore, only the whisker support agent prepared by the method of this invention, combined with the functional blending liquid of this invention, exhibits the most significant synergistic effect on product performance. Using other methods as substitutes is not as effective as the preparation method of this invention. Simultaneously, only the graphene sintered body raw material of this invention produces excellent product performance; using other raw materials as substitutes yields unsatisfactory results.

[0067] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0068] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flexible graphite grounding carbon fiber curing material, characterized in that, Including the following parts by weight of raw materials: 45-55 parts carbon fiber matrix, 15-20 parts flake graphite, 2-4 parts antioxidant, 2-4 parts toughening agent, 20-25 parts adhesive, 4-7 parts synergist, and 3-5 parts functional modifier.

2. The flexible graphite grounding carbon fiber curing material according to claim 1, characterized in that, The flexible graphite grounding carbon fiber cured material comprises the following raw materials in parts by weight: The composition includes 47.5 parts carbon fiber matrix, 17.5 parts flake graphite, 3 parts antioxidant, 3 parts toughening agent, 22.5 parts adhesive, 5.5 parts synergist, and 4 parts functional modifier.

3. The flexible graphite grounding carbon fiber curing material according to claim 1, characterized in that, The carbon fiber matrix is ​​a T700 type carbon fiber bundle with a single filament diameter of 7-10μm and a tensile strength of ≥4900MPa; The antioxidant is diphenylisodecyl phosphite; the toughening agent is carboxyl-terminated butadiene-acrylonitrile rubber with a number average molecular weight of 3000-5000. Flake graphite has a fixed carbon content of ≥99% and a particle size of 200-300 mesh; The adhesive is prepared by mixing 20-30 parts of phenolic resin, 20-25 parts of epoxy resin E-51, 2-4 parts of silane coupling agent KH-550, 8-12 parts of anhydrous ethanol, and 1-3 parts of dibutyl phthalate according to the weight ratio. The mixing temperature is 65℃, the mixing speed is 1000-1500 r / min, and the mixing time is 30 min to obtain the adhesive.

4. The flexible graphite grounding carbon fiber curing material according to claim 3, characterized in that, The preparation method of the additive is as follows: S11: Stir carbon nanotubes thoroughly in a sufficient amount of sulfuric acid solution with a mass fraction of 20-30%, then wash with water, filter, and dry; mix 5-8 parts of dried carbon nanotubes, 2-4 parts of nano lanthanum oxide, 7-11 parts of sodium lignosulfonate solution with a mass fraction of 5-8%, and 2-3 parts of nano silica sol thoroughly to obtain carbon nanotube solution. S12: Heat-treat montmorillonite at 110-120℃ for 10-15 min, then raise the temperature to 300-320℃ at a rate of 3-5℃ / min, hold for 35-45 min, then cool to 60℃ at a rate of 5-8℃ / min, and hold to obtain heat-treated montmorillonite. Mix 3-5 parts of wollastonite, 2-4 parts of nano-titanium oxide and 1-3 parts of 2-5% yttrium nitrate solution and add them to 4-7 parts of 5-8% sodium citrate solution and stir until homogeneous to obtain wollastonite solution. S13: Mix the heat-treated montmorillonite and wollastonite liquid in a weight ratio of (5-7):3 and ball mill them at a speed of 1000-1500 r / min for 2 hours. After ball milling, filter and dry to obtain montmorillonite-wollastonite modifier. S14: The montmorillonite-wollastonite modifier and carbon nanotube liquid are ultrasonically treated at a weight ratio of 3:(5-7), with an ultrasonic power of 350-400W for 1 hour. After ultrasonic treatment, the mixture is filtered and dried to obtain the modifier.

5. The flexible graphite grounding carbon fiber curing material according to claim 4, characterized in that, The wollastonite is acicular wollastonite with a particle size of 1-3 μm; the nano-titanium dioxide is anatase type with a particle size of 20-50 nm.

6. The flexible graphite grounding carbon fiber curing material according to claim 4, characterized in that, The montmorillonite is sodium-based montmorillonite with a particle size of 2-3 μm; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-15 nm and a length of 6-8 μm.

7. The flexible graphite grounding carbon fiber curing material according to claim 5, characterized in that, The preparation method of the functional modifier is as follows: S101: 5-8 parts of sheet graphene, 3-5 parts of nickel oxide and 2-3 parts of neodymium powder are blended and sintered for 1 hour at a sintering temperature of 350-370℃. After sintering, a sintered graphene body is obtained. S102: Mix 3-5 parts of β-cyclodextrin, 2-4 parts of sodium dodecylbenzenesulfonate solution (8% by mass), 2-4 parts of graphene sintered body, and 5-8 parts of chitosan solution (2-5% by mass) evenly to obtain a functional blending liquid. S103: The whisker support agent and functional blending liquid are ball-milled at a weight ratio of (8-10):5, with a ball milling speed of 1000-1500 r / min for 2 hours. After ball milling, the mixture is filtered and dried to obtain the functional modifier.

8. The flexible graphite grounding carbon fiber curing material according to claim 7, characterized in that, The preparation method of the whisker support agent is as follows: S103a: Preheat aluminum borate whiskers at 135-145℃ for 1 hour to obtain preheated aluminum borate whiskers. Mix the preheated aluminum borate whiskers, sodium silicate solution with a mass fraction of 2-5% and glass microspheres in a weight ratio of (3-5):7:(1-2) to obtain whisker solution. S103b: Mix 3-5 parts of nano-zirconia, 2-4 parts of sodium alginate powder and 4-6 parts of nano-silicon carbide evenly to obtain the additive; The whisker solution and additives were mixed at a weight ratio of (7-9):4 and ball-milled at a speed of 1500-1600 r / min for 2 hours. After the ball milling was completed, the mixture was filtered and dried to obtain the whisker support agent.

9. A flexible graphite grounding carbon fiber curing material according to claim 8, characterized in that, The aluminum borate whiskers have a particle size of 5-10 μm and an aspect ratio of 20-50:1; the glass microspheres have a density of 0.8-1.2 g / cm³. 3 The particle size is 10-50 μm; the particle size of nano-zirconia and nano-silicon carbide is 20-30 nm; the particle size of sheet graphene is 2-5 μm, the thickness is 1-5 nm, the number of layers is 4-6, and the specific surface area is 300-800 m². 2 / g.

10. A method for preparing a flexible graphite grounding carbon fiber cured material as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Dry the carbon fiber matrix to a moisture content of ≤0.5%. After high-temperature calcination to remove impurities, the flake graphite is mixed with adhesive, additive, functional modifier, antioxidant and toughening agent and ultrasonically dispersed for 20-30 minutes at an ultrasonic power of 500-550W to obtain a cured slurry. Step 2: Carbon fiber weaving and impregnation. The carbon fiber matrix from Step 1 is plain-woven into a woven tape with a weaving density of 20-30 strands / cm and a fiber tension of 5-8N. The woven tape is then immersed in a curing slurry for 10-15 minutes to ensure uniform adhesive coating on the surface of the carbon fiber woven tape. After draining off excess slurry, a prepreg tape is obtained. Step 3: Gradient curing molding. The prepreg tape is placed in an inert gas protective atmosphere for gradient curing to obtain the initial cured material. The material is first heated to 100-110℃ for 15 minutes in a preheating section, then heated to 200-220℃ for 35 minutes in a curing section, with a pressure of 0.3-0.8MPa applied during the curing process. Finally, it is cooled to 30-40℃ in a cooling section at a rate of 5-7℃ / min to obtain the initial cured material. Step 4: Post-flexibility treatment. The pre-cured material is ultrasonically cleaned at 300-350W for 5-10 minutes to remove residual slurry impurities on the surface. Then, it is subjected to low-temperature stretching and flexibility treatment at a stretching rate of 2-3 mm / min to eliminate residual stress inside the material, thus obtaining the flexible graphite grounding carbon fiber cured material of the present invention.

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