Mixed glue, carbon-carbon thermal insulation hard felt and preparation method thereof

Abstract

The invention provides mixed glue, a carbon-carbon heat preservation hard felt and a preparation method thereof, and particularly relates to the technical field of heat preservation plates. The mixed glue comprises high-viscosity phenolic resin, surface modified graphite, orientation-improved carbon nanotubes, carbon fibers and a water-soluble resin solution, wherein the viscosity of the high-viscosity phenolic resin is greater than 10,000 mPa. S. In the mixed glue provided by the invention, the high-viscosity phenolic resin forms a low-porosity bonding layer between the matrix felt layers through the synergistic effect of the high rheological property and the water-soluble resin, so that the bonding force is remarkably improved, and the density is not increased. The surface modified graphite and the oriented carbon nanotubes construct a three-dimensional heat conduction-mechanical network: the graphite optimizes the interfacial compatibility, and the carbon nanotubes provide oriented enhancement and cooperate with the carbon fibers to inhibit crack propagation, so that the heat conduction stability is ensured. The water-soluble resin enhances the wettability to the carbon cloth / graphite paper, and the anchoring effect of the phenolic resin is combined, so that the attachment layer is kept in a low-stress state at high temperature, and the problems of swelling and layering are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation panels, and in particular to a mixed adhesive, a carbon-carbon thermal insulation hard felt and a preparation method thereof. Background Art

[0002] At present, the interlayer bonding of carbon-carbon thermal insulation felt mainly relies on resin bonding. However, in the subsequent processing, after the resin is carbonized, its interlayer bonding layer is prone to form a porous structure, resulting in a significant reduction in the interlayer bonding strength. During use, this weak interface bonding is prone to cause delamination, which seriously affects the service life and performance stability of carbon-carbon thermal insulation felt.

[0003] In the prior art, the main methods to improve the interlayer bonding strength of carbon-carbon thermal insulation felt include: increasing the density of the base felt and increasing the amount of resin. Although these two methods can extend the service life of the felt and enhance the interlayer bonding strength to a certain extent, they will also significantly increase the overall density of the material. This change will directly affect the key performance indicators of carbon-carbon thermal insulation felt, especially the thermal conductivity, thereby reducing its actual application effect.

[0004] In addition, carbon-carbon thermal insulation hard felt usually needs to be attached with functional materials such as carbon cloth and graphite paper during use. However, it is difficult to ensure that these attached materials remain in a stable bonding state during subsequent processing or service by relying solely on resin bonding, and interface failure problems such as bulging, delamination, and shedding are very likely to occur, further limiting the reliability and application scope of the material.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] One of the purposes of the present invention is to provide a mixed glue, aiming to solve at least one of the above-mentioned technical problems in the prior art.

[0007] A second object of the present invention is to provide a carbon-carbon thermal insulation hard felt.

[0008] The third object of the present invention is to provide a method for preparing a carbon-carbon thermal insulation hard felt.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] The first aspect of the present invention provides a mixed glue, comprising a high-viscosity phenolic resin, surface-modified graphite, carbon nanotubes with improved orientation, carbon fibers and a water-soluble resin solution;

[0011] Wherein, the viscosity of the high-viscosity phenolic resin is greater than 10000 mPa.s.

[0012] Furthermore, the mass ratio of the high-viscosity phenolic resin, the surface-modified graphite, the carbon nanotubes with improved orientation, the carbon fiber, and the water-soluble resin solution is 20-30:2-5:5-10:2-5:1-5; wherein, the mass concentration of the water-soluble resin solution is 45-55 wt%.

[0013] Furthermore, the preparation method of the surface-modified graphite is: soaking graphite powder in a silanol solution and reacting for 30-60 min, and then obtaining the surface-modified graphite through solid-liquid separation and drying.

[0014] Preferably, the pH of the silanol solution is 4-5.

[0015] Preferably, the silanol solution includes a silane coupling agent and an alcohol solution.

[0016] Preferably, the silane coupling agent includes an amino silane and / or an epoxy silane.

[0017] Preferably, the alcohol solution includes an ethanol solution.

[0018] Preferably, in the ethanol solution, the volume concentration of ethanol is 95-99%, and the balance is deionized water.

[0019] Furthermore, the method of solid-liquid separation includes filtration or centrifugal separation.

[0020] Preferably, the drying temperature is 80-120 °C, and the time is 1-2 h.

[0021] Furthermore, the preparation method of the carbon nanotubes with improved orientation is: preliminarily dispersing the dispersion liquid of carbon nanotubes through the first ultrasonic wave; then re-dispersing through the second ultrasonic wave, then improving the orientation through the third ultrasonic wave, and finally removing the solvent to obtain the carbon nanotubes with improved orientation;

[0022] wherein, the frequency of the second ultrasonic wave is 20-100 kHz, and the power is 100-720 W;

[0023] The frequency of the third ultrasonic wave is greater than 500 kHz, and the power is 50-300 W.

[0024] Preferably, a ultrasonic generator is used for the second ultrasonic wave and the third ultrasonic wave.

[0025] Preferably, a ultrasonic cleaner is used for the first ultrasonic wave.

[0026] Preferably, the dispersion liquid of carbon nanotubes includes carbon nanotubes, a solvent, and a dispersant.

[0027] Preferably, the solvent includes water and / or ethanol.

[0028] Further, the length of the carbon fiber is 1 to 10 mm.

[0029] Preferably, the aspect ratio of the carbon fiber is 1000 to 10000:3 to 7.

[0030] Preferably, the water-soluble resin is WL-8405 water-soluble resin.

[0031] In a second aspect of the present invention, there is provided a carbon-carbon heat-insulating hard felt, comprising a plurality of carbon-carbon heat-insulating hard felt layers, and a mixed glue located between the carbon-carbon heat-insulating hard felt layers and / or on the surface of the carbon-carbon heat-insulating hard felt layers;

[0032] Wherein, the mixed glue is the mixed glue described in the first aspect.

[0033] In a third aspect of the present invention, there is provided a method for preparing the carbon-carbon heat-insulating hard felt, coating a mixed glue between and / or on the surface of the carbon-carbon heat-insulating hard felt layers, and then stacking the carbon-carbon heat-insulating hard felt layers layer by layer and performing hot pressing to obtain the carbon-carbon heat-insulating hard felt.

[0034] Further, the hot pressing is performed using a hot press.

[0035] Preferably, the process of the hot pressing is as follows: keeping warm at the first hot pressing temperature for 20 to 40 min, then raising the temperature to the second hot pressing temperature and keeping warm for 2 to 4 h; finally, lowering the temperature to below 90 °C and taking the carbon-carbon heat-insulating hard felt out of the hot press.

[0036] Preferably, the first hot pressing temperature is 100 to 120 °C.

[0037] Preferably, the second hot pressing temperature is 150 to 170 °C.

[0038] Further, at the first hot pressing temperature, the pressure of the hot press is 0.7 to 0.9 MPa.

[0039] Preferably, at the second hot pressing temperature, the pressure of the hot press is 1.8 to 2.2 MPa.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] Due to its high rheological properties, the high-viscosity phenolic resin in the hybrid adhesive provided by the present invention can fully fill the pores between the matrix felt layers. Combining with the wetting and penetration effects of the water-soluble resin solution, a bonding layer with a low porosity is formed, thereby effectively suppressing the generation of hole defects during carbonization without increasing the density of the matrix felt, and directionally enhancing the interlayer bonding force. At the same time, the surface-modified graphite and the orientation-regulated carbon nanotubes in the hybrid adhesive jointly construct a three-dimensional gradient thermal-conductive and mechanical network. The surface-modified graphite reduces the interlayer thermal stress by optimizing the interfacial compatibility, while the orientation-arranged carbon nanotubes provide directional reinforcement along the interlayer direction and cooperate with carbon fibers to inhibit crack propagation. These effects jointly ensure the stability of key properties such as the thermal conductivity of the matrix felt. In addition, the water-soluble resin solution in the hybrid adhesive improves the wettability of adhering materials such as carbon cloth and graphite paper. Combining with the strong anchoring effect of the high-viscosity phenolic resin, the surface adhering layer maintains a low interfacial stress state during high-temperature carbonization and subsequent service, completely avoiding failure phenomena such as bulging and delamination.

[0042] Due to the advantages of the above-mentioned hybrid adhesive, the carbon-carbon thermal insulation hard felt provided by the present invention significantly improves the interlayer bonding strength and surface adhesion performance of the carbon-carbon thermal insulation hard felt. Through the composite reinforcement mechanism of the hybrid adhesive, the carbon-carbon thermal insulation hard felt can still maintain high interfacial integrity under cyclic thermal shock, significantly extending its service life.

[0043] The preparation method of the carbon-carbon thermal insulation hard felt provided by the present invention combines the interlayer / surface coating of the hybrid adhesive with the hot pressing process, significantly shortening the preparation cycle and reducing energy consumption. By directionally enhancing the interlayer bonding force and surface adhesion stability through the hybrid adhesive and coating process, while avoiding the increase in the density of the matrix felt, it ensures that key performance indicators such as the thermal conductivity are not affected by deterioration. The fluidity and densification effects of the hybrid adhesive during the hot pressing process can effectively eliminate interfacial defects such as holes and cracks, improving the overall structural uniformity and service life of the hard felt. Detailed Embodiments

[0044] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0045] In the following text, the terms "including", "having" and their cognates that can be used in various embodiments of the present invention are only intended to represent specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be construed as first excluding the existence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components, or combinations of the foregoing items.

[0046] The first aspect of the present invention provides a hybrid adhesive, comprising a high-viscosity phenolic resin, surface-modified graphite, carbon nanotubes with improved orientation, carbon fibers, and a water-soluble resin solution;

[0047] Among them, the viscosity of the high-viscosity phenolic resin > 10000 mPa·s.

[0048] Due to its high rheological properties, the high-viscosity phenolic resin in the hybrid adhesive provided by the present invention can fully fill the pores between the matrix felt layers. Combining with the wetting and penetration effects of the water-soluble resin solution, a bonding layer with a low porosity is formed, thereby effectively suppressing the generation of pore defects during carbonization without increasing the density of the matrix felt and directionally enhancing the interlayer bonding force. At the same time, the surface-modified graphite and the orientation-regulated carbon nanotubes in the hybrid adhesive jointly construct a three-dimensional gradient thermal-conductive and mechanical network. The surface-modified graphite reduces the interlayer thermal stress by optimizing the interfacial compatibility, while the orientation-arranged carbon nanotubes provide directional reinforcement along the interlayer direction and cooperate with the carbon fibers to inhibit crack propagation. These effects jointly ensure the stability of key properties such as the thermal conductivity of the matrix felt. In addition, the water-soluble resin solution in the hybrid adhesive improves the wettability of adherend materials such as carbon cloth and graphite paper. Combining with the strong anchoring effect of the high-viscosity phenolic resin, the surface adherend layer maintains a low interfacial stress state during high-temperature carbonization and subsequent service, completely avoiding failure phenomena such as bulging and delamination.

[0049] Specifically, the viscosity of the high-viscosity phenolic resin > 10000 mPa·s can accurately fill the 10 - 100 μm-level interlayer pores, reduce the porosity of the substrate, and improve the strength and heat insulation performance of the matrix material.

[0050] During the specific use process, if the viscosity of the high-viscosity phenolic resin is less than 10000 mPa·s, the resin is left standing in an environment of 0°C - 10°C for 48 h for treatment.

[0051] The surface of the surface-modified graphite can form chemical bonds to improve the interfacial bonding with the matrix material. On this basis, as a solid filler, the surface-modified graphite can fill the voids between the carbon fibers, increase the interlayer contact area, and further improve the interlayer bonding force. At the same time, the uniform distribution of the surface-modified graphite can also improve the coating effect of the hybrid adhesive, avoiding poor interlayer bonding caused by uneven hybrid adhesive, thereby optimizing the structural performance of the matrix material as a whole.

[0052] Carbon nanotubes themselves have high thermal conductivity, but when they are dispersed in the matrix material, the thermal conductivity of the overall material can be reduced through interface thermal resistance and scattering effects. By regulating the arrangement and dispersion state of carbon nanotubes, a complex heat conduction path can be formed, thereby reducing heat transfer. In particular, carbon nanotubes with improved arrangement can effectively improve the thermal insulation performance of carbon-carbon thermal insulation felt. Secondly, carbon nanotubes also have high aspect ratio and high strength characteristics, which can effectively transfer interlayer stress. When external loads are applied, carbon nanotubes transfer stress from one layer to another like a "bridge", reducing stress concentration and thus enhancing interlayer bonding. In addition, the active functional groups on the surface of carbon nanotubes (such as carboxyl and amino groups) can react chemically with the matrix material to form stable chemical bonds, further enhancing the interface bonding force. In the case of uniform dispersion, the van der Waals force between carbon nanotubes and the matrix can also improve the interface bonding strength to a certain extent.

[0053] Compared with surface-modified graphite, carbon fiber has coarser powder particles and higher hardness. When carbon fiber is fully mixed with high-viscosity phenolic resin, the resin layer formed after carbonization treatment is not only harder, but also has a stronger bond with the upper and lower substrates.

[0054] During the high-temperature treatment process, the water-soluble resin will first undergo a carbonization reaction and gradually transform into a stable carbon structure. This carbonized structure can be tightly bonded to the matrix material, thereby significantly improving the bonding strength between layers at the microscopic level and enhancing the thermal stability of the matrix material.

[0055] Furthermore, the mass ratio of the high-viscosity phenolic resin, the surface-modified graphite, the carbon nanotubes with improved orientation, the carbon fibers and the water-soluble resin solution is 20-30:2-5:5-10:2-5:1-5; wherein the mass concentration of the water-soluble resin solution is 45-55wt%.

[0056] Typically but not limiting, the mass fraction of the high viscosity phenolic resin can be, for example, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts or 30 parts; the mass fraction of the surface modified graphite can be, for example, 2 parts, 3 parts, 4 parts or 5 parts; the mass fraction of the carbon nanotubes with improved orientation can be, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts; the mass fraction of the carbon fiber can be, for example, 2 parts, 3 parts, 4 parts or 5 parts; the mass fraction of the water-soluble resin solution can be, for example, 1 part, 2 parts, 3 parts, 4 parts or 5 parts. The above mass fractions are all within the range of 20-30:2-5:5-10:2-5:1-5.

[0057] Typically but not restrictively, the mass concentration of the water-soluble resin solution can be, for example, 45 wt%, 47 wt%, 49 wt%, 51 wt%, 52 wt%, 53 wt%, 55 wt%, or any value within the range of 45 wt% to 55 wt%.

[0058] Further, the method for preparing the surface-modified graphite is as follows: Immerse graphite powder in a silanol solution and react for 30 to 60 minutes, and then obtain the surface-modified graphite through solid-liquid separation and drying.

[0059] Preferably, the pH of the silanol solution is 4 to 5. If the pH does not meet the requirements, an appropriate amount of acetic acid can be added for adjustment.

[0060] Preferably, the silanol solution includes a silane coupling agent and an alcohol solution.

[0061] A silane coupling agent is an organic-inorganic hybrid molecule with the general formula Y-Si-(OR)3, where Y is an organic functional group (such as an amino group, an epoxy group, etc.) that can chemically react with the resin; and OR is a hydrolyzable alkoxy group that hydrolyzes to form silanol (Si-OH), which then undergoes a condensation reaction with the hydroxyl group (-OH) on the surface of inorganic materials (such as graphite powder, carbon fiber, carbon fiber powder) to form a stable Si-O-Si bond. Through this treatment, a strong chemical bonding can be formed between the surface-modified graphite powder and the matrix material, thereby significantly improving the adhesion.

[0062] Preferably, the silane coupling agent includes an amino silane and / or an epoxy silane.

[0063] Preferably, the alcohol solution includes an ethanol solution.

[0064] Preferably, in the ethanol solution, the volume concentration of ethanol is 95 to 99%, and the balance is deionized water.

[0065] Typically but not restrictively, in the ethanol solution, the volume concentration of ethanol can be, for example, 95%, 96%, 97%, 98%, 99%, or any value within the range of 95% to 99%. The balance is made up to 100% of the volume with deionized water.

[0066] Further, the method of solid-liquid separation includes filtration or centrifugal separation.

[0067] Preferably, the drying temperature is 80 to 120 °C and the time is 1 to 2 hours.

[0068] Typically but not restrictively, the drying temperature may be, for example, 80°C, 90°C, 100°C, 110°C, 120°C, or any temperature within the range of 80°C to 120°C; the drying time may be, for example, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, or any time within the range of 1 hour to 2 hours.

[0069] Furthermore, the preparation method of the carbon nanotubes with improved alignment is: preliminarily dispersing the dispersion of carbon nanotubes by a first ultrasound; then dispersing again by a second ultrasound, then improving the alignment by a third ultrasound, and finally removing the solvent to obtain the carbon nanotubes with improved alignment;

[0070] Wherein, the frequency of the second ultrasound is 20-100kHz, and the power is 100-720W;

[0071] The third ultrasound has a frequency greater than 500kHz and a power of 50-300W.

[0072] Typically but not limiting, the frequency of the second ultrasound may be, for example, 20kHz, 30kHz, 40kHz, 50kHz, 60kHz, 70kHz, 80kHz, 90kHz or 100kHz, or any value within the range of 20kHz to 100kHz; the power of the second ultrasound may be, for example, 100W, 200W, 300W, 400W, 500W, 600W or 720W, or any value within the range of 100W to 720W. Typically but not limiting, the frequency of the third ultrasound may be, for example, 550kHz, 600kHz, 700kHz, 800kHz, 900kHz, 1MHz, 1.2MHz, 1.5MHz, 2MHz, 3MHz, 4MHz or higher, as long as it is greater than 500kHz; the power of the third ultrasound may be, for example, 50W, 100W, 150W, 200W, 250W or 300W, or any value within the range of 50W to 300W. Preferably, the second ultrasound and the third ultrasound are performed using an ultrasound generator.

[0073] Preferably, the first ultrasound is performed using an ultrasonic cleaning machine.

[0074] Preferably, the carbon nanotube dispersion comprises carbon nanotubes, a solvent and a dispersant.

[0075] Preferably, the solvent comprises water and / or ethanol.

[0076] Furthermore, the length of the carbon fiber is 1 to 10 mm.

[0077] Typically but not restrictively, the length of the carbon fiber can be, for example, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm, or can also be any value within the range of 1 mm to 10 mm.

[0078] Preferably, the aspect ratio of the carbon fiber is (1000 - 10000):(3 - 7).

[0079] Typically but not restrictively, the aspect ratio of the carbon fiber can be, for example, 1000:3, 1000:4, 1000:5, 1000:6, 1000:7, 2000:3, 2000:4, 2000:5, 2000:6, 2000:7, 3000:3, 3000:4, 3000:5, 3000:6, 3000:7, 4000:3, 4000:4, 4000:5, 4000:6, 4000:7, 5000:3, 5000:4, 5000:5, 5000:6, 5000:7, 6000:3, 6000:4, 6000:5, 6000:6, 6000:7, 7000:3, 7000:4, 7000:5, 7000:6, 7000:7, 8000:3, 8000:4, 8000:5, 8000:6, 8000:7, 9000:3, 9000:4, 9000:5, 9000:6, 9000:7, 10000:3, 10000:4, 10000:5, 10000:6 or 10000:7, or can also be any value within the range of (1000 - 10000):(3 - 7).

[0080] Preferably, the water-soluble resin is 8405 water-soluble resin.

[0081] The second aspect of the present invention provides a carbon-carbon heat-insulating hard felt, comprising a plurality of carbon-carbon heat-insulating hard felt layers, and a mixed glue located between the carbon-carbon heat-insulating hard felt layers and / or on the surface of the carbon-carbon heat-insulating hard felt layers;

[0082] wherein, the mixed glue is the mixed glue described in the first aspect.

[0083] For the carbon-carbon heat-insulating hard felt provided by the present invention, in view of the advantages of the above-mentioned mixed glue, the interlayer bonding strength and surface adhesion performance of the carbon-carbon heat-insulating hard felt are significantly improved. Through the composite strengthening mechanism of the mixed glue, the carbon-carbon heat-insulating hard felt can still maintain high interface integrity under cyclic thermal shock, and the service life is significantly prolonged.

[0084] The third aspect of the present invention provides a preparation method of the carbon-carbon heat-insulating hard felt described above. A mixed glue is coated between the carbon-carbon heat-insulating hard felt layers and / or on the surface, and then the carbon-carbon heat-insulating hard felt layers are stacked layer by layer and hot-pressed to obtain the carbon-carbon heat-insulating hard felt.

[0085] The preparation method of the carbon-carbon heat-insulating rigid felt provided by the present invention combines interlayer / surface coating of a mixed adhesive with a hot pressing process, significantly shortening the preparation cycle and reducing energy consumption. By using the mixed adhesive and the coating process, the interlayer bonding force and the surface adhesion stability are enhanced directionally, while avoiding the increase in the density of the matrix felt, ensuring that key performance indicators such as the thermal conductivity are not deteriorated. During the hot pressing process, the fluidity and densification effect of the mixed adhesive can effectively eliminate interface defects such as pores and cracks, improving the overall structural uniformity and service life of the rigid felt.

[0086] Further, the hot pressing is carried out using a hot press.

[0087] Preferably, the process of the hot pressing is as follows: keep warm at the first hot pressing temperature for 20 - 40 minutes, then raise the temperature to the second hot pressing temperature and keep warm for 2 - 4 hours; finally, lower the temperature to below 90 °C, and take the carbon-carbon heat-insulating rigid felt out of the hot press.

[0088] Preferably, the first hot pressing temperature is 100 - 120 °C.

[0089] Typical but non-limiting, the first hot pressing temperature can be, for example, 100 °C, 110 °C, 120 °C, or any temperature within the range of 100 °C - 120 °C.

[0090] Preferably, the second hot pressing temperature is 150 - 170 °C.

[0091] Typical but non-limiting, the second hot pressing temperature can be, for example, 150 °C, 160 °C, 170 °C, or any temperature within the range of 150 °C - 170 °C.

[0092] Further, at the first hot pressing temperature, the pressure of the hot press is 0.7 - 0.9 MPa.

[0093] Typical but non-limiting, at the first hot pressing temperature, the pressure of the hot press can be, for example, 0.7 MPa, 0.8 MPa, 0.9 MPa, or any pressure within the range of 0.7 - 0.9 MPa.

[0094] Preferably, at the second hot pressing temperature, the pressure of the hot press is 1.8 - 2.2 MPa.

[0095] Typical but non-limiting, at the second hot pressing temperature, the pressure of the hot press can be, for example, 1.8 MPa, 2.0 MPa, 2.2 MPa, or any pressure within the range of 1.8 - 2.2 MPa.

[0096] The present invention will be further illustrated by specific examples and comparative examples below. However, it should be understood that these examples are only for more detailed description and should not be construed as limiting the present invention in any way. For the raw materials used in the examples and comparative examples of the present invention, unless otherwise specified, they are carried out under conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, unless the manufacturer is specified, are all conventional products that can be obtained by purchasing on the market.

[0097] Example 1

[0098] This example provides a mixed glue, and the mass ratio of high-viscosity phenolic resin (viscosity is 15000 mPa·s), surface-modified graphite, carbon nanotubes with improved orientation, carbon fiber (1 - 10 mm, 3000:5) and water-soluble resin (WL-8405) solution is 25:3:8:3:3; wherein, the mass concentration of the water-soluble resin solution is 50 wt%.

[0099] Among them, the preparation method of the surface-modified graphite is as follows: Add aminosilane into an ethanol aqueous solution with a volume concentration of 95% to form an aminosilane solution (volume concentration is 9%), and the pH is 4.6. Immerse the graphite in the aminosilane solution and stir for 40 minutes to ensure that the solution evenly covers the surface of the graphite. Filter the treated graphite powder to remove the excess solution. Dry it at 100 °C for 1.5 hours to obtain the surface-modified graphite.

[0100] The preparation method of the carbon nanotubes with improved orientation is as follows: Disperse the carbon nanotubes in ethanol, and add a dispersant to improve the dispersion effect to obtain a carbon nanotube dispersion. Use an ultrasonic cleaner to preliminarily disperse the carbon nanotube dispersion to ensure that the carbon nanotubes are evenly dispersed. Then use an ultrasonic generator to place the carbon nanotube dispersion in an ultrasonic field, adjust the frequency to 60 kHz and the power to 500 W to ensure that the sound field is uniform. Turn on the ultrasonic wave so that the carbon nanotubes are evenly dispersed under the action of the acoustic radiation force and acoustic streaming effect in the sound field, and then adjust the frequency of the ultrasonic wave to 600 kHz and the power to 200 W to control the alignment direction of the carbon nanotubes. Under the action of the ultrasonic wave, the carbon nanotubes will gradually align along the sound field direction. Finally, evaporate the solvent to fix the alignment structure to obtain the carbon nanotubes with improved orientation.

[0101] Example 2

[0102] This example provides a mixed glue, and the mass ratio of high-viscosity phenolic resin (viscosity is 15000 mPa·s), surface-modified graphite, carbon nanotubes with improved orientation, carbon fiber (1 - 10 mm, 3000:5) and water-soluble resin (WL-8405) solution is 20:4:8:4:5.

[0103] The preparation methods and parameters of other raw materials are the same as those in Example 1 and will not be elaborated here.

[0104] Example 3

[0105] This example provides a hybrid glue, which consists of high-viscosity phenolic resin (viscosity of 15000 mPa·s), surface-modified graphite, carbon nanotubes with improved orientation, carbon fiber (1 - 10 mm, 3000:5), and water-soluble resin (WL-8405) solution in a mass ratio of 23:5:10:5:5.

[0106] The preparation methods and parameters of other raw materials are the same as those in Example 1 and will not be elaborated here.

[0107] Example 4

[0108] This example provides a hybrid glue, which consists of high-viscosity phenolic resin (viscosity of 15000 mPa·s), surface-modified graphite, carbon nanotubes with improved orientation, carbon fiber (1 - 10 mm, 3000:5), and water-soluble resin (WL-8405) solution in a mass ratio of 30:2:5:2:1.

[0109] The preparation methods and parameters of other raw materials are the same as those in Example 1 and will not be elaborated here.

[0110] Example 5

[0111] This example provides a hybrid glue. The difference from Example 1 is that the concentration of the water-soluble resin solution is 45 wt%, and the other raw materials and ratios are the same as those in Example 1 and will not be elaborated here.

[0112] Example 6

[0113] This example provides a hybrid glue. The difference from Example 1 is that the concentration of the water-soluble resin solution is 55 wt%, and the other raw materials and ratios are the same as those in Example 1 and will not be elaborated here.

[0114] Example 7

[0115] This example provides a hybrid glue. The difference from Example 2 is that high-viscosity phenolic resin with a viscosity of 12000 mPa·s is used to replace high-viscosity phenolic resin with a viscosity of 15000 mPa·s, and the other raw materials and ratios are the same as those in Example 2 and will not be elaborated here.

[0116] Example 8

[0117] This example provides a hybrid glue. The difference from Example 1 is that the concentration of the water-soluble resin solution is 30 wt%, and the other raw materials and ratios are the same as those in Example 1 and will not be elaborated here.

[0118] Example 9

[0119] This embodiment provides a hybrid glue, which is different from that of Embodiment 1 in that the concentration of the water-soluble resin solution is 60 wt%, and the other raw materials and ratios are the same as those of Embodiment 1, which will not be elaborated here.

[0120] Comparative Example 1

[0121] This comparative example provides a hybrid glue, which is different from that of Embodiment 2 in that graphite is directly used to replace the surface-modified graphite; carbon nanotubes are used to replace the carbon nanotubes with improved orientation. The other ratios and raw materials are the same as those of Embodiment 2, which will not be elaborated here.

[0122] Comparative Example 2

[0123] This comparative example provides a hybrid glue, which is different from that of Embodiment 2 in that graphite is directly used to replace the surface-modified graphite, and the other ratios and raw materials are the same as those of Embodiment 2, which will not be elaborated here.

[0124] Comparative Example 3

[0125] This comparative example provides a hybrid glue, which is different from that of Embodiment 2 in that carbon nanotubes are used to replace the carbon nanotubes with improved orientation, and the other ratios and raw materials are the same as those of Embodiment 2, which will not be elaborated here.

[0126] Comparative Example 4

[0127] This comparative example provides a hybrid glue, which is different from that of Embodiment 2 in that carbon fiber is not used, and the other ratios and raw materials are the same as those of Embodiment 2, which will not be elaborated here.

[0128] Comparative Example 5

[0129] This comparative example provides a hybrid glue, which is different from that of Embodiment 2 in that the water-soluble resin solution is not used, and the other ratios and raw materials are the same as those of Embodiment 2, which will not be elaborated here.

[0130] Comparative Example 6

[0131] This comparative example provides a hybrid glue, which is different from that of Embodiment 2 in that phenolic resin (viscosity of 7000 mPa·s) is used to replace the high-viscosity phenolic resin, and the other ratios and raw materials are the same as those of Embodiment 2, which will not be elaborated here.

[0132] Examples 10 - 18 and Comparative Examples 7 - 12

[0133] These examples and comparative examples provide a carbon-carbon heat-insulating rigid felt, and the PAN (polyacrylonitrile)-based carbon fiber cloth is cut into the same specification. The hybrid glues provided in Examples 1 - 9 and Comparative Examples 1 - 6 are respectively and evenly brushed on the PAN (polyacrylonitrile)-based carbon fiber cloth with a roller, and the PAN (polyacrylonitrile)-based carbon fiber cloth of the same number of layers is laminated and bonded into a whole. When brushing the glue, it is confirmed that the surface of the rigid felt is flat without protrusions.

[0134] After applying the glue, the material is hot-pressed on a hot press. The hot-pressing temperature is maintained at 110°C for 30 minutes, then continues to rise to 160°C and is kept constant for 3 hours. The pressure of the press is 0.8 MPa at 110°C and 2 MPa at 160°C.

[0135] After the pressing is completed, the temperature of the press is reduced to below 90°C, and the material can be removed from the press. The treatment is completed to obtain a carbon-carbon heat-insulating hard felt.

[0136] Comparative Example 13

[0137] This comparative example provides a carbon-carbon heat-insulating hard felt. The PAN (polyacrylonitrile)-based carbon fiber cloth is cut into the same specifications as those in the above-mentioned examples and comparative examples. Conventional phenolic resin (viscosity < 7500 mPa·s) is evenly brushed on the PAN (polyacrylonitrile)-based carbon fiber cloth with a roller. The PAN (polyacrylonitrile)-based carbon fiber cloth of the same number of layers is laminated and bonded into a whole. When brushing the glue, it is confirmed that the surface of the hard felt is flat without protrusions.

[0138] Test Example

[0139] The carbon-carbon heat-insulating hard felts obtained in Examples 10 - 18 and Comparative Examples 7 - 13 are subjected to performance tests, specifically including density, thermal conductivity, and interlayer bonding strength.

[0140] The process of the interlayer bonding test: Samples are taken from the corresponding test specimens. The size of the specimens is 50 * 20 * 50 mm. The specimens are placed on a universal testing machine, and the upper and lower fixtures respectively clamp the upper and lower ends of the specimens. Then the universal testing machine is started for tensile testing, and the measured result is the interlayer bonding strength of the corresponding felt body.

[0141] The data obtained from the performance tests are shown in Table 1 below.

[0142] Table 1

[0143]

[0144]

[0145] Finally, it should be noted that the above-described embodiments are only specific embodiments of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that any person skilled in the technical field of the present invention can still modify the technical solutions described in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims described.

Claims

1. A hybrid glue, characterized in that, It includes high-viscosity phenolic resin, surface-modified graphite, carbon nanotubes with improved orientation, carbon fiber and water-soluble resin solution; Among them, the viscosity of the high-viscosity phenolic resin > 10,000 mPa·s.

2. The hybrid glue according to claim 1, wherein The mass ratio of the high-viscosity phenolic resin, the surface-modified graphite, the carbon nanotubes with improved orientation, the carbon fiber and the water-soluble resin solution is 20-30:2-5:5-10:2-5:1-5; Among them, the mass concentration of the water-soluble resin solution is 45-55 wt%.

3. The hybrid glue according to claim 1, characterized in that, The preparation method of the surface-modified graphite is: soaking graphite powder in a silanol solution and reacting for 30-60 min, and then obtaining the surface-modified graphite through solid-liquid separation and drying; Preferably, the pH of the silanol solution is 4-5; Preferably, the silanol solution includes a silane coupling agent and an alcohol solution; Preferably, the silane coupling agent includes an amino silane and / or an epoxy silane; Preferably, the alcohol solution includes an ethanol solution; Preferably, in the ethanol solution, the volume concentration of ethanol is 95-99%, and the balance is deionized water.

4. The hybrid glue according to claim 3, characterized in that, The method of solid-liquid separation includes filtration or centrifugal separation; Preferably, the drying temperature is 80-120 °C and the time is 1-2 h.

5. The hybrid glue according to any one of claims 1 to 4, characterized in that The preparation method of the carbon nanotubes with improved orientation is: preliminarily dispersing the dispersion of carbon nanotubes through the first ultrasonic wave; then re-dispersing through the second ultrasonic wave, and then improving the orientation through the third ultrasonic wave, and finally removing the solvent to obtain the carbon nanotubes with improved orientation; Among them, the frequency of the second ultrasonic wave is 20-100 kHz and the power is 100-720 W; The frequency of the third ultrasonic wave is greater than 500 kHz and the power is 50-300 W; Preferably, a ultrasonic wave generator is used for the second ultrasonic wave and the third ultrasonic wave; Preferably, a ultrasonic wave cleaner is used for the first ultrasonic wave; Preferably, the dispersion of carbon nanotubes includes carbon nanotubes, a solvent and a dispersant; Preferably, the solvent includes water and / or ethanol.

6. The hybrid glue according to any one of claims 1 to 4, characterized in that, The length of the carbon fiber is 1-10 mm; Preferably, the aspect ratio of the carbon fiber is (1000-10000):(3-7); Preferably, the water-soluble resin is WL-8405 water-soluble resin.

7. A carbon-carbon heat-insulating hard felt, characterized in that, It includes several carbon-carbon heat-insulating hard felt layers, and a mixed glue located between the carbon-carbon heat-insulating hard felt layers and / or on the surface of the carbon-carbon heat-insulating hard felt layers; Among them, the mixed glue is the mixed glue according to any one of claims 1-6.

8. A method for preparing the carbon-carbon heat-insulating rigid felt according to claim 7, characterized in that, Coat the mixed glue between and / or on the surface of the carbon-carbon heat-insulating hard felt layers, and then stack the carbon-carbon heat-insulating hard felt layers layer by layer and perform hot pressing to obtain the carbon-carbon heat-insulating hard felt.

9. The preparation method according to claim 8, characterized in that, Use a hot press for the hot pressing; Preferably, the process of the hot pressing is: keep warm at the first hot pressing temperature for 20-40 min, then raise the temperature to the second hot pressing temperature and keep warm for 2-4 h; finally, cool down to below 90 °C and take out the hot press to obtain the carbon-carbon heat-insulating hard felt; Preferably, the first hot pressing temperature is 100-120 °C; Preferably, the second hot pressing temperature is 150-170 °C.

10. The preparation method according to claim 9, characterized in that, At the first hot pressing temperature, the pressure of the hot press is 0.7-0.9 MPa; Preferably, at the second hot pressing temperature, the pressure of the hot press is 1.8 - 2.2 MPa.

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