Carbon / carbon article and method of making same

Abstract

The invention provides a carbon / carbon product and a preparation method thereof.The preparation method comprises the following steps that carbon fibers, first resin, a dispersing agent and a solvent are mixed, and carbon fiber slurry is obtained; carrying out molding and curing treatment on the carbon fiber slurry to obtain bundled fibers; mixing the bundled fibers, a carbonaceous filler, second resin and a reinforcing agent to obtain a mixture; the reinforcing agent comprises one or more of short carbon fibers and silicon carbide powder; and sequentially carrying out compression molding, carbonization, densification and graphitization treatment on the mixture to obtain the carbon / carbon product. According to the preparation method, cluster fibers are adopted to replace carbon fibers to serve as a fiber network framework, and meanwhile, the carbon filler and the specific type of reinforcing agent have the synergistic effect, so that the prepared carbon / carbon product has better mechanical properties such as bending strength, tensile strength, compressive strength and shear strength; the process for preparing the carbon fiber preform in the traditional carbon / carbon product preparation process is not needed, the process is simple, the process period can be shortened, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of carbon composite materials technology, and in particular to carbon / carbon products and their preparation methods. Background Technology

[0002] Carbon / carbon products possess excellent properties such as high strength, high modulus, high temperature resistance, and corrosion resistance, and are widely used in key areas such as photovoltaic thermal field components and semiconductor manufacturing fixtures. Traditional manufacturing processes for carbon / carbon products mainly employ a flat-plate needle punching method to prepare carbon fiber preforms, followed by densification processes such as chemical vapor deposition and liquid phase impregnation. However, this process suffers from long production cycles and low production efficiency, significantly hindering industrial-scale production. Summary of the Invention

[0003] Therefore, it is necessary to provide a carbon / carbon product and its preparation method that can shorten the production cycle and improve production efficiency.

[0004] One aspect of the present invention provides a method for preparing carbon / carbon products, comprising the following steps:

[0005] Carbon fiber, first resin, dispersant and solvent are mixed to obtain carbon fiber slurry;

[0006] The carbon fiber slurry is subjected to molding and curing treatment to obtain bundled fibers;

[0007] The bundled fibers, carbon filler, second resin, and reinforcing agent are mixed to obtain a mixture; the reinforcing agent includes one or more of chopped carbon fibers and silicon carbide powder.

[0008] The mixture is subjected to molding, carbonization, densification and graphitization processes in sequence to obtain carbon / carbon products.

[0009] The above-mentioned method for preparing carbon / carbon products involves mixing carbon fibers, a first resin, a dispersant, and a solvent to obtain a carbon fiber slurry. The carbon fiber slurry is then molded and cured to form bundled fibers. Inside the bundled fibers, multiple carbon fibers are cured and oriented. Simultaneously, the bundled fibers, carbonaceous filler, a second resin, and a specific type of reinforcing agent are mixed to obtain a mixture, which is then sequentially subjected to compression molding, carbonization, densification, and graphitization to obtain the carbon / carbon product. In this carbon / carbon product, the bundled fibers serve as the fiber network skeleton, which can conduct and disperse the load on the local carbon / carbon product, preventing excessive concentration of local loads or stress. Meanwhile, the carbonaceous filler and the specific type of reinforcing agent are bonded and distributed on the fiber network skeleton by the second resin, thereby giving the carbon / carbon product superior mechanical properties such as flexural strength, compressive strength, tensile strength, and shear strength.

[0010] Furthermore, unlike traditional carbon / carbon product manufacturing methods that require the preparation of carbon fiber preforms to provide good strength, the aforementioned method uses bundled fibers instead of carbon fibers as the fiber network skeleton. Simultaneously, it employs carbonaceous fillers and specific types of reinforcing agents to work synergistically, resulting in carbon / carbon products with superior mechanical properties such as flexural strength, compressive strength, tensile strength, and shear strength. Therefore, this method eliminates the need for the traditional carbon / carbon product manufacturing process of preparing carbon fiber preforms, omitting the complex processes of carbon fiber preform layup, needle punching, stitching, or other weaving steps. Moreover, the method is simpler, shortening the production cycle and thus improving production efficiency.

[0011] In some implementations, one or more of the following conditions are met:

[0012] (1) The carbon fiber is obtained by opening and loosening the waste of carbon fiber preform;

[0013] (2) The length of the carbon fiber is 4mm~11mm;

[0014] (3) The width of the carbon fiber is 0.1mm~0.5mm;

[0015] (4) The aspect ratio of the carbon fiber is (8~110):1.

[0016] In some implementations, one or more of the following conditions are met:

[0017] (1) The length of the bundled fiber is 15mm~25mm;

[0018] (2) The diameter of the bundled fibers is 0.5 mm to 1 mm;

[0019] (3) The aspect ratio of the bundled fibers is (15~50):1.

[0020] In some embodiments, the carbon fiber slurry comprises, by weight, 45 to 70 parts carbon fiber, 16 to 24 parts first resin, 14 to 24 parts solvent, and 0.5 to 3 parts dispersant.

[0021] In some embodiments, the carbon fiber slurry is subjected to a molding and curing process, including the following steps.

[0022] The carbon fiber slurry is extruded to obtain a preform of the bundled fiber, and the preform of the bundled fiber is thermo-cured to obtain the bundled fiber.

[0023] In some embodiments, the extrusion molding temperature is 90°C to 110°C, the thermosetting temperature is 130°C to 150°C, and the thermosetting time is 40 min to 60 min.

[0024] In some implementations, one or more of the following conditions are met:

[0025] (1) The filler includes one or more of carbon powder and graphite powder;

[0026] (2) The first resin includes at least one of phenolic resin, urea-formaldehyde resin, epoxy resin, polyurethane and polyimide;

[0027] (3) The second resin includes at least one of phenolic resin, urea-formaldehyde resin, epoxy resin, polyurethane and polyimide.

[0028] In some embodiments, the mixture comprises, by weight, 35 to 60 parts bundled fibers, 19 to 34 parts filler, 16 to 26 parts secondary resin, and 2 to 5 parts reinforcing agent.

[0029] In some implementations, one or more of the following conditions are met:

[0030] (1) The molding temperature is 200℃~250℃;

[0031] (2) The pressure of the molding process is 10MPa~15MPa;

[0032] (3) The molding time is 30 min to 50 min.

[0033] In another aspect, the present invention provides a carbon / carbon product prepared by the above-described preparation method, including carbon / carbon sheets.

[0034] The aforementioned carbon / carbon products possess superior flexural strength, compressive strength, tensile strength, and shear strength, meeting the application requirements of industrial fields such as photovoltaic thermal fields and semiconductor fixtures. Detailed Implementation

[0035] To facilitate understanding of the present invention, a more complete description will be given below with reference to relevant embodiments. Preferred embodiments of the invention are shown below. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the disclosure of the invention will be achieved.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] Carbon / carbon products possess excellent properties such as high strength, high modulus, high temperature resistance, and corrosion resistance. These superior properties rely to some extent on precisely woven and / or needle-punched carbon fiber preforms. These preforms, acting as a reinforcing phase, improve the flexural strength, compressive strength, tensile strength, and shear strength of carbon / carbon products. However, the preparation process of carbon fiber preforms is complex, and the price of carbon fiber raw materials is high, resulting in a high final production cost for carbon / carbon products.

[0038] The production process of carbon / carbon products generates a large amount of irregular carbon fiber preform waste, which is often treated as industrial waste and disposed of through landfill and / or incineration. This results in the waste of high-value carbon fiber resources and generates a significant amount of solid waste, contradicting the concepts of green manufacturing and a circular economy. Traditional methods for recycling waste carbon fiber preforms often involve downgrading, which involves pyrolysis and / or shearing and shredding the waste. However, downgrading still presents certain problems: Pyrolysis-derived waste carbon fibers undergo surface oxidation, creating defects that damage the original mechanical properties of the fibers. These surface defects also affect the interfacial bonding strength between the waste carbon fibers and the matrix, thus impacting the mechanical properties of the final carbon / carbon product. Shearing-shredded waste carbon fibers have significantly reduced length and aspect ratio. Directly using these fibers in carbon / carbon product manufacturing results in a scattered and disordered distribution within the matrix, failing to form a continuous and effective carbon fiber network. Furthermore, the uneven distribution of these disordered fibers within the matrix can lead to agglomeration, resulting in localized areas of excessively high or low carbon fiber content in the carbon / carbon product. This stress concentration can cause cracking or damage.

[0039] One aspect of the present invention provides a method for preparing carbon / carbon products, comprising the following steps:

[0040] Carbon fiber, first resin, dispersant and solvent are mixed to obtain carbon fiber slurry;

[0041] The carbon fiber slurry is subjected to molding and curing treatment to obtain bundled fibers;

[0042] The bundled fibers, carbon filler, second resin, and reinforcing agent are mixed to obtain a mixture; the reinforcing agent includes one or more of chopped carbon fibers and silicon carbide powder.

[0043] The mixture is subjected to molding, carbonization, densification and graphitization processes in sequence to obtain carbon / carbon products.

[0044] The above-mentioned method for preparing carbon / carbon products involves mixing carbon fibers, a first resin, a dispersant, and a solvent to obtain a carbon fiber slurry. The carbon fiber slurry is then molded and cured to form bundled fibers. Inside the bundled fibers, multiple carbon fibers are cured and oriented. Simultaneously, the bundled fibers, carbonaceous filler, a second resin, and a specific type of reinforcing agent are mixed to obtain a mixture, which is then sequentially subjected to compression molding, carbonization, densification, and graphitization to obtain the carbon / carbon product. In this carbon / carbon product, the bundled fibers serve as the fiber network skeleton, which can conduct and disperse the load on the local carbon / carbon product, preventing excessive concentration of local loads or stress. Meanwhile, the carbonaceous filler and the specific type of reinforcing agent are bonded and distributed on the fiber network skeleton by the second resin, thereby giving the carbon / carbon product superior mechanical properties such as flexural strength, compressive strength, tensile strength, and shear strength.

[0045] Furthermore, unlike traditional carbon / carbon product manufacturing methods that require the preparation of carbon fiber preforms to provide good strength, the aforementioned method uses bundled fibers instead of carbon fibers as the fiber network skeleton. Simultaneously, it employs carbonaceous fillers and specific types of reinforcing agents to work synergistically, resulting in carbon / carbon products with superior mechanical properties such as flexural strength, compressive strength, tensile strength, and shear strength. Therefore, this method eliminates the need for the traditional carbon / carbon product manufacturing process of preparing carbon fiber preforms, omitting the complex processes of carbon fiber preform layup, needle punching, stitching, or other weaving steps. Moreover, the method is simpler, shortening the production cycle and thus improving production efficiency.

[0046] In some embodiments, the length of the chopped carbon fiber is 1 mm to 5 mm. As an example, the length of the chopped carbon fiber can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or any two of the above values, such as 2 mm to 4 mm.

[0047] In some embodiments, the particle size of silicon carbide powder is 1 μm to 10 μm. As an example, the particle size of silicon carbide powder may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm or any two of the above values, for example, 3 μm to 7 μm.

[0048] The above-mentioned method for preparing carbon / carbon products uses chopped carbon fibers and / or silicon carbide powder as reinforcing agents, which can strengthen the matrix, fill microcracks, and synergistically enhance the bending strength, compressive strength, tensile strength and shear strength of carbon / carbon products with the fiber network formed by bundled fibers.

[0049] In some embodiments, the carbon fiber is obtained by opening up waste carbon fiber preforms.

[0050] Optionally, carbon fiber preform waste includes carbon fiber preform scraps.

[0051] Understandably, carbon fiber preform scrap comes from the carbon fiber preform scrap generated during the production of carbon / carbon composite materials.

[0052] Optionally, the carbon fiber preform scraps include at least one of carbon fiber mesh scraps, carbon fiber felt scraps, carbon fiber fabric scraps, and carbon fiber woven fabric scraps.

[0053] In some implementations, the opening process includes roll-tear opening and / or high-speed airflow opening.

[0054] Furthermore, the opening process includes the following steps: feeding the carbon fiber preform waste into a two-roller opener and / or an airflow opener for 5 to 15 minutes. As an example, the opening time is 5 minutes, 8 minutes, 10 minutes, 13 minutes, 15 minutes, or any two of the above values, such as 8 minutes to 10 minutes.

[0055] The carbon / carbon product preparation method described above, which uses an opening process instead of traditional pyrolysis and / or shearing and pulverizing to prepare carbon fibers, can retain the original length, intrinsic mechanical properties and surface condition of carbon fibers to a greater extent, and avoid irreversible damage to carbon fibers.

[0056] In some embodiments, the length of the carbon fiber is 4mm to 11mm. As an example, the length of the carbon fiber can be 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm or any two of the above values, for example, 5mm to 10mm.

[0057] In some implementations, the width of the carbon fiber is 0.1 mm to 0.5 mm.

[0058] In some implementations, the aspect ratio of the carbon fiber is (8~110):1.

[0059] The above-mentioned method for preparing carbon / carbon products utilizes carbon fibers obtained from carbon fiber preform waste through a loosening process to form bundled fibers as the reinforcing phase of carbon / carbon products. This method recycles and utilizes the carbon fiber preform waste, which is otherwise worthless and requires additional solid waste disposal costs, thereby reducing the production cost of carbon / carbon products.

[0060] In some implementations, the bundled fibers are in the form of strips.

[0061] In some embodiments, the length of the bundled fibers is 15mm to 25mm. As an example, the length of the bundled fibers may be 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm or any two of the above values, such as 18mm to 20mm.

[0062] In some implementations, the diameter of the bundled fibers is 0.5 mm to 1 mm.

[0063] In some implementations, the aspect ratio of the bundled fibers is (15~50):1.

[0064] In some embodiments, the carbon fiber slurry comprises, by weight, 45 to 70 parts carbon fiber, 16 to 24 parts first resin, 14 to 24 parts solvent, and 0.5 to 3 parts dispersant.

[0065] As an example, the mass fraction of carbon fiber can be 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, or any two of the above values, such as 55 parts to 60 parts.

[0066] As an example, the mass fraction of the first resin can be 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, or any two of the above values, for example, 20 parts to 22 parts.

[0067] As an example, the mass fraction of the solvent can be 14, 16, 18, 20, 22, 24 parts or any two of the above values, for example, 18 to 20 parts.

[0068] As an example, the mass fraction of the dispersant can be 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, or any two of the above values, such as 1.5 parts to 2 parts.

[0069] In some embodiments, the carbon fiber slurry comprises, by weight, 45 to 60 parts carbon fiber, 20 to 22 parts first resin, 18 to 20 parts solvent, and 1.5 to 2 parts dispersant. Further, the carbon fiber slurry comprises, by weight, 55 to 60 parts carbon fiber, 20 to 22 parts first resin, 18 to 20 parts solvent, and 1.5 to 2 parts dispersant.

[0070] In some embodiments, the solvent includes organic solvents and inorganic solvents.

[0071] Alternatively, the organic solvent may include anhydrous ethanol.

[0072] Optionally, the inorganic solvent includes deionized water.

[0073] In some embodiments, the dispersant includes at least one of sodium dodecylbenzenesulfonate, sodium fatty alcohol ether sulfate, sodium secondary alkyl sulfonate, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, and polymethyl methacrylate.

[0074] In some embodiments, the carbon fiber, the first resin, the dispersant, and the solvent are mixed, including the following steps:

[0075] Carbon fiber, a first resin, a dispersant, and a solvent are added to a high-speed mixer at a stirring speed of 400 rpm to 1000 rpm for 20 min to 45 min to obtain a carbon fiber slurry. As an example, the stirring speed can be 400 rpm, 600 rpm, 800 rpm, 1000 rpm, or any two of the above values, such as 600 rpm to 800 rpm. As an example, the stirring time can be 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, or any two of the above values, such as 30 min to 35 min.

[0076] In some embodiments, the carbon fiber slurry undergoes a molding and curing process, including the following steps.

[0077] Carbon fiber slurry is extruded to obtain a preform of bundled fibers, and the preform of bundled fibers is thermo-cured to obtain bundled fibers.

[0078] In some embodiments, the extrusion molding temperature is 90°C to 110°C. For example, the extrusion molding temperature can be 90°C, 95°C, 100°C, 105°C, 110°C, or any two of the above values, such as 100°C to 110°C. The thermosetting temperature is 130°C to 150°C. For example, the thermosetting temperature can be 130°C, 135°C, 140°C, 145°C, 150°C, or any two of the above values, such as 135°C to 140°C. The thermosetting time is 40 min to 60 min. For example, the thermosetting time can be 40 min, 45 min, 50 min, 55 min, 60 min, or any two of the above values, such as 45 min to 50 min.

[0079] In some embodiments, extrusion molding includes the following steps: feeding carbon fiber slurry into a twin-screw granulator and / or a bundled fiber forming machine to obtain a preform of bundled fibers; the extrusion speed of the preform of bundled fibers is 500 mm / min to 1000 mm / min.

[0080] In some embodiments, the filler includes one or more of carbon powder and graphite powder.

[0081] In some embodiments, the particle size of the graphite powder is 10 μm to 40 μm. As an example, the particle size of the graphite powder may be 10 μm, 20 μm, 30 μm, 40 μm, or any two of the above values, such as 20 μm to 30 μm.

[0082] In some embodiments, the particle size of the toner is 10 μm to 30 μm. As an example, the particle size of the toner may be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or any two of the above values, such as 15 μm to 25 μm.

[0083] In some embodiments, the first resin includes at least one of phenolic resin, urea-formaldehyde resin, epoxy resin, polyurethane, and polyimide.

[0084] In some embodiments, the solid content of the first resin is 70% to 90%. As an example, the solid content of the first resin may be 70%, 75%, 80%, 85%, 90%, or any two of the above values, for example, 75% to 85%.

[0085] In some embodiments, the second resin includes at least one of phenolic resin, urea-formaldehyde resin, epoxy resin, polyurethane, and polyimide.

[0086] In some embodiments, the solid content of the second resin is 70% to 90%. As an example, the solid content of the second resin may be 70%, 75%, 80%, 85%, 90%, or any two of the above values, for example, 75% to 85%.

[0087] In some embodiments, bundled fibers, fillers, a second resin, and reinforcing agents are fed into a high-speed mixer at a stirring speed of 800 r / min to 1200 r / min for a stirring time of 10 min to 35 min to obtain a mixture. As an example, the stirring speed can be 800 r / min, 900 r / min, 1000 r / min, 1100 r / min, 1200 r / min, or any two of the above values, for example, 900 r / min to 1100 r / min. As an example, the stirring time can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, or any two of the above values, for example, 20 min to 25 min.

[0088] In some embodiments, the mixture comprises, by weight, 35 to 60 parts bundled fibers, 19 to 34 parts filler, 16 to 26 parts secondary resin, and 2 to 5 parts reinforcing agent.

[0089] As an example, the mass fraction of the bundled fibers can be 35, 40, 45, 50, 55, 60, or any two of the above values, for example, 45 to 50.

[0090] As an example, the mass fraction of the filler can be 19 parts, 22 parts, 25 parts, 28 parts, 31 parts, 34 parts, or any two of the above values ​​within the range, such as 25 parts to 28 parts.

[0091] As an example, the mass fraction of the second resin can be 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, or any two of the above values, for example, 20 parts to 22 parts.

[0092] As an example, the mass fraction of the reinforcing agent can be 2 parts, 3 parts, 4 parts, 5 parts, or any two of the above values, such as 3 to 4 parts.

[0093] In some embodiments, the mixture comprises, by weight, 45 to 50 parts bundled fibers, 25 to 28 parts filler, 20 to 22 parts secondary resin, and 3 to 4 parts reinforcing agent.

[0094] In some embodiments, the molding temperature is 200°C to 250°C. As an example, the molding temperature may be 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, or any two of the above values, such as 220°C to 230°C.

[0095] In some embodiments, the compression molding pressure is 10 MPa to 15 MPa. As an example, the compression molding pressure may be 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, or any two of the above values, for example, 12 MPa to 14 MPa.

[0096] In some embodiments, the molding time is 30 min to 50 min. As an example, the molding time can be 30 min, 35 min, 40 min, 45 min, 50 min, or any two of the above values, such as 35 min to 40 min.

[0097] The above-mentioned method for preparing carbon / carbon products uses bundled fibers of a specific composition as prefabricated units for carbon / carbon products. These fibers can be uniformly filled in a molding die and rapidly molded at a specific temperature, further compressing the traditional production cycle of carbon / carbon products and thus achieving the goal of short-cycle production of carbon / carbon products.

[0098] In some embodiments, the carbonization temperature is 800℃~1050℃, the carbonization time is 0.5h~2h, and the carbonization atmosphere is nitrogen.

[0099] In some embodiments, the densification process includes vapor deposition densification and / or liquid phase impregnation densification.

[0100] Understandably, compression molding yields carbon / carbon product green bodies.

[0101] Furthermore, the density of the carbon / carbon product green body is 1.3 g / cm³. 3 ~1.4g / cm 3 The density of carbon / carbon product green bodies after densification treatment is 1.5 g / cm³. 3 ~1.6g / cm 3 .

[0102] In some embodiments, the temperature for vapor deposition densification is 1000°C to 1150°C, and the time for vapor deposition densification is 240h to 480h.

[0103] In some implementations, the pressure for vapor deposition densification is 1 kPa to 5 kPa.

[0104] In some implementations, the carbon source gas for vapor-phase deposition densification includes methane.

[0105] In some embodiments, the impregnating liquid for liquid-phase impregnation and densification includes at least one of furan resin, epoxy resin, phenolic resin, and bitumen.

[0106] In some embodiments, the viscosity of the impregnation solution is 1000 mPa·s to 3000 mPa·s.

[0107] In some embodiments, the impregnation temperature for liquid phase impregnation densification is 30°C to 40°C.

[0108] In some embodiments, the impregnation time for liquid phase impregnation densification is 4 h to 8 h.

[0109] In some embodiments, the impregnation pressure for liquid phase impregnation densification is 1 MPa to 3 MPa.

[0110] In some embodiments, the impregnation curing temperature for liquid phase impregnation densification is 150-240°C.

[0111] In some embodiments, the impregnation carbonization temperature for liquid phase impregnation densification is 800°C to 1050°C.

[0112] In some embodiments, the liquid phase impregnation and densification time is 160h to 200h.

[0113] In some embodiments, the graphitization temperature is 1750℃~1850℃, the graphitization time is 4h~10h, and the graphitization atmosphere is argon.

[0114] The above-mentioned method for preparing carbon / carbon products involves bundled fibers of a specific composition that, after molding, densification, pyrolysis, and other treatments, can bond tightly with the matrix of the carbon / carbon product. This allows external loads to be effectively transferred to the bundled fibers through the matrix-bundled fiber interface, thereby maximizing the high strength characteristics of the carbon fibers in the bundled fibers.

[0115] In another aspect, the present invention provides a carbon / carbon product prepared by the above-described method for preparing carbon / carbon products, including carbon / carbon sheets.

[0116] The aforementioned carbon / carbon products possess superior flexural strength, compressive strength, tensile strength, and shear strength, meeting the application requirements of industrial fields such as photovoltaic thermal fields and semiconductor fixtures.

[0117] The following are specific examples.

[0118] Example 1

[0119] S1. Opening treatment. The scraps of carbon fiber preforms are fed into a two-roller opener for 10 minutes to obtain carbon fibers with a length of 5mm to 8mm (width of 0.2 to 0.4mm, length-to-width ratio of (12.5 to 40): 1).

[0120] S2. Preparation of carbon fiber slurry. According to the mass proportions, 60 parts of carbon fiber, 20 parts of phenolic resin (model: Shandong Shengquan TA-02 phenolic resin, solid content: 80wt%, with the mass of phenolic resin as 20 parts, the same below), 18 parts of anhydrous ethanol and 2 parts of sodium dodecylbenzenesulfonate are added to a high-speed mixer and mixed for 30 minutes at a speed of 800 r / min to obtain carbon fiber slurry.

[0121] S3. Bundled Fiber Molding and Curing. Carbon fiber slurry is fed into a twin-screw granulator, with an extrusion temperature of 90℃ and an extrusion speed of 800mm / min to obtain a bundled fiber preform. The bundled fiber preform is cut into strips with a length of 20mm and then placed in a 140℃ oven for heat curing for 45min to obtain bundled fibers (diameter of 0.5mm and aspect ratio of 40:1).

[0122] S4. Preparation of the mixture. Weigh 50 parts of bundled fiber, 25 parts of graphite powder, 20 parts of phenolic resin and 3 parts of silicon carbide powder, and put them into a high-speed mixer and mix for 20 minutes at a speed of 1000 r / min to obtain the mixture.

[0123] S5. Compression molding process. The mixture is placed into a mold for compression molding at a temperature of 220℃, a pressure of 12MPa, and a time of 40min. After cooling to room temperature (20℃±5℃), the mixture is demolded to obtain a carbon / carbon sheet green body.

[0124] S6. Carbonization treatment. Place the carbon / carbon sheet green blank in a nitrogen atmosphere at 900℃ and keep it for 1.5 hours.

[0125] S7. Densification treatment. The carbon / carbon sheet blank after carbonization treatment is placed in a furan resin impregnation solution with a viscosity of 2000 mPa·s. The impregnation temperature for liquid phase impregnation and densification is 36℃, the impregnation time is 5h, the impregnation pressure is 2MPa, the impregnation curing temperature is 200℃, the impregnation carbonization temperature is 900℃, and the liquid phase impregnation and densification time is 192h.

[0126] S8. Graphitization treatment. The carbon / carbon sheet green blank after the densification treatment is placed in an argon atmosphere at 1800℃ and kept for 4 hours.

[0127] Example 2

[0128] S1. Opening treatment. The scraps of carbon fiber preforms are fed into a high-speed airflow opening machine for 8 minutes to open the carbon fibers with a length of 7mm~10mm.

[0129] S2. Preparation of carbon fiber slurry. Weigh 55 parts of carbon fiber, 22 parts of phenolic resin (solid content of 80%, model: Shandong Shengquan TA-02 phenolic resin), 20 parts of anhydrous ethanol and 1.5 parts of polyvinyl alcohol, and mix them in a high-speed mixer for 35 minutes at a speed of 600 r / min to obtain carbon fiber slurry.

[0130] S3. Bundled Fiber Molding and Curing. The carbon fiber slurry is fed into a bundled fiber molding machine. The bundling temperature is 100℃ and the speed is 900mm / min to obtain a bundled fiber preform. Then, it is placed in a 135℃ oven for heat curing for 50 minutes. After curing, it is cut into strips with a length of 18mm to obtain bundled fibers (diameter of 0.6mm and aspect ratio of 30:1).

[0131] S4. Preparation of the mixture. Weigh 45 parts of bundled fiber, 28 parts of carbon powder, 22 parts of phenolic resin and 4 parts of 3mm short-cut carbon fiber, and put them into a high-speed mixer and mix for 25 minutes at a speed of 1100 r / min to obtain the mixture.

[0132] S5. Compression molding process. The mixture is placed into a mold for compression molding at a temperature of 230℃, a pressure of 14MPa, and a time of 35min. After cooling to room temperature (20℃±5℃), the mixture is demolded to obtain a carbon / carbon sheet green blank.

[0133] S6. Carbonization treatment. Place the carbon / carbon sheet green blank in a nitrogen atmosphere at 900℃ and keep it for 1.5 hours.

[0134] S7. Densification treatment. Methane was used as the carbon source gas to perform vapor phase deposition densification treatment on the carbon / carbon sheet green blank after carbonization. The vapor phase deposition densification temperature was 1100℃, the pressure was 3kPa, and the time was 240h.

[0135] S8. Graphitization treatment. The carbon / carbon sheet green blank after the densification treatment is placed in an argon atmosphere at 1800℃ for 4 hours.

[0136] Example 3

[0137] The preparation method of Example 3 is basically the same as that of Example 1, except that: S2, the specific composition of the carbon fiber slurry in the preparation of carbon fiber slurry;

[0138] That is, the carbon fiber slurry includes 70 parts carbon fiber, 24 parts phenolic resin, 24 parts anhydrous ethanol, and 3 parts sodium dodecylbenzene sulfonate.

[0139] Example 4

[0140] The preparation method of Example 4 is basically the same as that of Example 1, except that the specific composition of the carbon fiber slurry is different.

[0141] That is, the carbon fiber slurry includes 45 parts carbon fiber, 16 parts phenolic resin, 14 parts anhydrous ethanol, and 0.5 parts sodium dodecylbenzene sulfonate.

[0142] Example 5

[0143] The preparation method of Example 5 is basically the same as that of Example 1, except for the specific composition of the mixture;

[0144] The mixture consists of 35 parts bundled fibers, 34 parts graphite powder, 26 parts phenolic resin, and 5 parts silicon carbide powder.

[0145] Example 6

[0146] The preparation method of Example 6 is basically the same as that of Example 1, except for the specific composition of the mixture;

[0147] The mixture consists of 60 parts bundled fibers, 19 parts graphite powder, 16 parts phenolic resin, and 2 parts silicon carbide powder.

[0148] Example 7

[0149] The preparation method of Example 7 is basically the same as that of Example 1, except that the length of the bundled fiber is 25 mm.

[0150] Comparative Example 1

[0151] The process employs conventional flat-plate needle drilling and vapor deposition, specifically including the following steps:

[0152] S1. A 10mm thick carbon fiber preform was prepared from T700 carbon fiber using a flat needle punching process, with a needle punching density of 50 needles / cm. 2 .

[0153] S2. The carbon fiber preform obtained by flat needle punching is densified by chemical vapor deposition, with methane as the carbon source gas, a deposition temperature of 1100℃, a pressure of 5kPa, and a time of 480h.

[0154] S3. After densification, graphitization treatment is carried out. The high-temperature treatment temperature is 1800℃ and the time is 4 hours.

[0155] Comparative Example 2

[0156] The preparation method of Comparative Example 2 is basically the same as that of Example 1, except that the reinforcing agent in the mixture is omitted.

[0157] That is, S4, preparing the mixture. Weigh 50 parts of bundled fiber, 25 parts of graphite powder, and 25 parts of phenolic resin, and mix them in a high-speed mixer to obtain the mixture.

[0158] Comparative Example 3

[0159] The preparation method of Comparative Example 3 is basically the same as that of Example 1, except that the steps of preparing carbon fiber slurry and forming and curing bundled fibers are omitted.

[0160] 45 parts of carbon fiber, 20 parts of graphite powder, 25 parts of phenolic resin and 10 parts of silicon carbide were weighed and mixed to obtain a mixture.

[0161] Compared with the volume of the same mass mixture in Example 1, the volume of Comparative Example 3 is 3 times that of the mixture in Example 1, which makes it impossible to carry out effective filler molding and corresponding subsequent processing.

[0162] Comparative Example 4

[0163] The preparation method of Comparative Example 4 is basically the same as that of Example 1, except that the opening treatment is replaced by shearing treatment.

[0164] That is, the carbon fiber preform scraps are sheared. After shearing, the carbon fibers are agglomerated and contain small pieces of carbon fiber preform scraps. This can easily cause blockage during the preparation of bundled fibers, making continuous production difficult. Therefore, the carbon fibers obtained by shearing cannot be used for slurry preparation and subsequent processing.

[0165] The carbon / carbon sheets prepared in each embodiment and comparative example were subjected to mechanical property tests, including:

[0166] (1) Bending resistance test: in accordance with standard GB / T 40398-2021;

[0167] (2) Compression test: in accordance with standard GB / T 34559-2017;

[0168] (3) Tensile strength test: in accordance with standard GB / T 33501-2017;

[0169] (4) Shear test: in accordance with standard GB / T 40388-2021.

[0170] The test results are shown in Table 1.

[0171] Table 1

[0172]

[0173] As shown in Examples 1-7, Comparative Examples 1-4, and Table 1, the mechanical properties of Examples 1-7 are not significantly different from those of Comparative Example 1 prepared by the conventional method. This demonstrates that the carbon / carbon substrates prepared by this method have comparable mechanical properties to those prepared by conventional needle-punching combined with vapor deposition, meeting the application requirements of photovoltaic thermal fields and semiconductor fixtures. Furthermore, the raw material cost of Examples 1-7 is 40% of that of Comparative Example 1, and the production cycle of Examples 1-7 is approximately 18 days, significantly less than the 40 days of Comparative Example 1. This proves that this preparation method can significantly reduce the production cost of carbon / carbon substrates and shorten the production cycle. Comparative Example 2 demonstrates that the reinforcing agent is crucial for the preparation of carbon / carbon substrates with superior mechanical properties.

[0174] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0175] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing carbon / carbon products, characterized in that, Includes the following steps: Carbon fiber, first resin, dispersant and solvent are mixed to obtain carbon fiber slurry; The carbon fiber slurry is subjected to molding and curing treatment to obtain bundled fibers; The bundled fibers, carbon filler, second resin, and reinforcing agent are mixed to obtain a mixture; the reinforcing agent includes one or more of chopped carbon fibers and silicon carbide powder. The mixture is subjected to molding, carbonization, densification and graphitization processes in sequence to obtain carbon / carbon products.

2. The method for preparing carbon / carbon products as described in claim 1, characterized in that, One or more of the following conditions must be met: (1) The carbon fiber is obtained by opening and loosening the waste of carbon fiber preform; (2) The length of the carbon fiber is 4mm~11mm; (3) The width of the carbon fiber is 0.1mm~0.5mm; (4) The aspect ratio of the carbon fiber is (8~110):

1.

3. The method for preparing carbon / carbon products as described in claim 1, characterized in that, One or more of the following conditions must be met: (1) The length of the bundled fiber is 15mm~25mm; (2) The diameter of the bundled fibers is 0.5 mm to 1 mm; (3) The aspect ratio of the bundled fibers is (15~50):

1.

4. The method for preparing carbon / carbon products as described in claim 1, characterized in that, The carbon fiber slurry, by mass, comprises 45 to 70 parts carbon fiber, 16 to 24 parts first resin, 14 to 24 parts solvent, and 0.5 to 3 parts dispersant.

5. The method for preparing carbon / carbon products as described in claim 1, characterized in that, The carbon fiber slurry is subjected to molding and curing treatment, including the following steps: The carbon fiber slurry is extruded to obtain a bundled fiber preform, and the bundled fiber preform is thermo-cured to obtain the bundled fiber.

6. The method for preparing carbon / carbon products as described in claim 5, characterized in that, The extrusion molding temperature is 90℃~110℃, the thermosetting temperature is 130℃~150℃, and the thermosetting time is 40min~60min.

7. The method for preparing carbon / carbon products according to any one of claims 1 to 6, characterized in that, One or more of the following conditions must be met: (1) The carbonaceous filler includes one or more of carbon powder and graphite powder; (2) The first resin includes at least one of phenolic resin, urea-formaldehyde resin, epoxy resin, polyurethane and polyimide; (3) The second resin includes at least one of phenolic resin, urea-formaldehyde resin, epoxy resin, polyurethane and polyimide.

8. The method for preparing carbon / carbon products according to any one of claims 1 to 6, characterized in that, The mixture, by mass parts, comprises 35 to 60 parts bundled fibers, 19 to 34 parts carbonaceous filler, 16 to 26 parts secondary resin, and 2 to 5 parts reinforcing agent.

9. The method for preparing carbon / carbon products according to any one of claims 1 to 6, characterized in that, One or more of the following conditions must be met: (1) The molding temperature is 200℃~250℃; (2) The pressure of the molding process is 10MPa~15MPa; (3) The molding time is 30 min to 50 min.

10. A carbon / carbon product, characterized in that, The carbon / carbon sheet is prepared by the preparation method according to any one of claims 1 to 9.

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