High loft carbon carbon thermal insulation mat and method of making

Abstract

The application provides a high-loft carbon-carbon thermal insulation hard felt and a preparation method thereof, and relates to the technical field of carbon fiber thermal insulation felt.The preparation method comprises the following steps: (a) a shaped carbon fiber net is first subjected to double-side glue spraying through a double-net clamping type glue spraying equipment, then the excess glue on the carbon fiber net is removed to control the glue content, then part of the solvent on the carbon fiber net is removed through a radiation type drying device, then the remaining solvent on the carbon fiber net is removed through a hot air penetration type oven, and meanwhile, the glue is cross-linked and solidified, so that a reinforced carbon fiber net is obtained; and (b) the reinforced carbon fiber net is sequentially subjected to layering hot pressing and carbonization treatment, so that a carbon-carbon thermal insulation hard felt is obtained.The application solves the technical problem that the existing carbon-carbon thermal insulation hard felt has many heat transfer channels, so that the thermal insulation performance is poor, and achieves the technical effect that the heat transfer channels are greatly reduced, the porosity is improved, the thermal conductivity is effectively reduced, and the thermal insulation performance of the carbon-carbon thermal insulation hard felt is improved.

Description

Technical Field

[0001] This invention relates to the technical field of carbon fiber insulation felt, and in particular to a high-loft carbon fiber insulation rigid felt and its preparation method. Background Technology

[0002] Currently, the density of carbon carbon insulation rigid felt is generally around 0.18 g / cm³. 3 -0.21g / cm 3 The thermal conductivity of carbon-carbon insulating felt is between 0.2 and 0.4. The insulation performance of carbon-carbon insulating felt is mainly reflected in its thermal conductivity; the lower the thermal conductivity, the better the insulation performance. There are two main ways to reduce the thermal conductivity of carbon-carbon insulating felt: one is to reduce the density of the carbon-carbon insulating felt, and the other is to reduce the number of heat transfer channels in the carbon-carbon insulating felt.

[0003] Most existing carbon-carbon thermal insulation rigid felts are made of pre-oxidized integral felt, and their reinforcement method is integral needle punching. This results in a large number of fibers distributed in the Z direction inside the carbon-carbon rigid felt, which increases the heat transfer channels inside the carbon-carbon thermal insulation rigid felt and affects the actual thermal insulation performance of the carbon-carbon thermal insulation rigid felt.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One of the objectives of this invention is to provide a method for preparing a high-loft carbon-carbon thermal insulation rigid felt, which can solve the technical problem that existing carbon-carbon thermal insulation rigid felts have poor thermal insulation performance due to the large number of heat transfer channels.

[0006] The second objective of this invention is to provide a high-loft carbon-carbon thermal insulation felt with low thermal conductivity and excellent thermal insulation performance.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0008] Firstly, a method for preparing a high-loft carbon-carbon thermal insulation rigid felt includes the following steps:

[0009] (a) The shaped carbon fiber mesh is first coated with glue on both sides through a double-mesh clamping glue coating equipment, and then the excess glue on the carbon fiber mesh is removed to control the glue content. Then, it is dried by a radiation drying device to remove some of the solvent on the carbon fiber mesh. After that, it is dried by a hot air penetration oven to remove the remaining solvent on the carbon fiber mesh, while the glue is cross-linked and cured to obtain a reinforced carbon fiber mesh.

[0010] (b) The reinforced carbon fiber mesh obtained in step (a) is sequentially subjected to layup hot pressing and carbonization treatment to obtain the carbon-carbon thermal insulation felt.

[0011] Furthermore, the dual-net clamping coating equipment applies coating to the upper and lower surfaces of the shaped carbon fiber mesh through a coat hanger-type solution dispensing device and a flipping mechanism.

[0012] The shaped carbon fiber mesh is fed into a double-mesh clamping adhesive coating equipment by a transmission pressure roller under the action of the front and rear conveying rollers at a speed ratio not exceeding 5%.

[0013] Furthermore, the resin used in the coating process includes phenolic resin.

[0014] Furthermore, the method for removing excess adhesive from the carbon fiber mesh includes removing excess adhesive using a vacuum suction device.

[0015] Furthermore, the temperature of the radiant drying device is 60℃-80℃.

[0016] Furthermore, the temperature program of the hot air penetration oven is to raise the temperature from 80°C to 180°C, hold it at that temperature, and then lower it to 60°C.

[0017] Furthermore, the shaping method includes heat setting;

[0018] The temperature for hot-setting is 180℃-220℃.

[0019] Secondly, a carbon-carbon thermal insulation rigid felt prepared by any of the above-described preparation methods.

[0020] Furthermore, the density of the carbon-carbon thermal insulation felt is 0.08 g / cm³. 3 -0.16g / cm 3 ;

[0021] The porosity of the carbon-carbon thermal insulation felt is 91.12%-95.56%;

[0022] The bulkiness of the carbon-carbon thermal insulation felt is 6.25 cm. 3 / g-12.5cm 3 / g.

[0023] Furthermore, the thermal conductivity of the carbon-carbon insulating rigid felt is 0.05-0.1.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] The present invention provides a method for preparing high-loft carbon-carbon thermal insulation rigid felt. Through a specific composite reinforcement process, the high loft and high porosity of the carbon fiber mesh are achieved. Specifically, a double-mesh clamping resin coating device is first used to coat the shaped carbon fiber mesh with resin solution. This allows for double-sided quantitative resin coating of the carbon fiber mesh under extremely low tension, avoiding uneven dispersion of the resin solution in the thick fiber mesh. Residual resin is then removed from the carbon fiber mesh to control the resin content, thereby controlling the weight and density of the final product. Finally, a radiation drying device is used for pre-drying to remove some of the solvent from the carbon fiber mesh. The radiation drying device enables rapid and uniform drying of the resin solution in the fiber mesh, quickly removing some of the solvent and reducing resin migration, thus maintaining the resin's position within the fiber. The carbon fiber mesh is uniformly distributed within the fiber mesh, and then completely dried using a hot air penetration oven. Simultaneously, it is heated to a sufficient temperature to completely cross-link and cure the adhesive (resin). The hot air penetration oven completely removes any remaining solvent from the fiber mesh. The hot air penetration further loosens the arrangement of the fibers, and the temperature of the hot air causes the resin remaining at the fiber interlacing points to cross-link and cure, thus strengthening the overall carbon fiber mesh. In summary, through the synergistic effect of each step, the resulting carbon fiber mesh (mesh core) possesses high bulk and high porosity, along with certain strength and durability. In the subsequent hot-pressing and lamination stage, by controlling the compression ratio and the proportion of phenolic resin to the fiber mesh, the carbon fiber insulation felt product can achieve low density, high porosity, and high insulation performance.

[0026] The high-loft carbon-carbon thermal insulation felt provided by this invention has low density, high porosity, and low thermal conductivity, thus exhibiting excellent thermal insulation performance. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a first cross-sectional view of a hanger-type solution dispensing device provided in one embodiment of the present invention;

[0029] Figure 2 This is a second cross-sectional view of a hanger-type solution dispensing device provided in one embodiment of the present invention;

[0030] Figure 3 A schematic diagram of the composite reinforcement process provided in one embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the first resin solution coating zone provided in one embodiment of the present invention.

[0032] Icons: 1-Resin solution inlet pipe; 2-Gas inlet; 3-Solution channel; 100-Network laying device; 200-Drive curtain; 300-Hot ironing roller; 400-First resin solution coating zone; 401-Metal support roller; 402-First drive pressure roller; 403-Hanger-type solution distribution device; 404-Clamping curtain; 500-Drive roller; 600-Second resin solution coating zone; 601-Second drive pressure roller; 700-Vacuum liquid suction device; 800-Radiation drying device; 900-Hot air penetration oven. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] According to a first aspect of the present invention, a method for preparing a high-loft carbon-carbon thermal insulation rigid felt is provided, comprising the following steps:

[0035] (a) The shaped carbon fiber mesh is first coated with glue on both sides through a double-mesh clamping glue coating equipment, and then the excess glue on the carbon fiber mesh is removed to control the glue content. Then, it is dried by a radiation drying device to remove some of the solvent on the carbon fiber mesh. After that, it is dried by a hot air penetration oven to remove the remaining solvent on the carbon fiber mesh, while the glue is cross-linked and cured to obtain a reinforced carbon fiber mesh.

[0036] (b) The reinforced carbon fiber mesh obtained in step (a) is sequentially subjected to layup hot pressing and carbonization treatment to obtain carbon carbon thermal insulation felt.

[0037] The present invention provides a method for preparing high-loft carbon-carbon thermal insulation rigid felt. Through a specific composite reinforcement process, the high loft and high porosity of the carbon fiber mesh are achieved. Specifically, a double-mesh clamping resin coating device is first used to coat the shaped carbon fiber mesh with resin solution. This allows for double-sided quantitative resin coating of the carbon fiber mesh under extremely low tension, avoiding uneven dispersion of the resin solution in the thick fiber mesh. Residual resin is then removed from the carbon fiber mesh to control the resin content, thereby controlling the weight and density of the final product. Finally, a radiation drying device is used for pre-drying to remove some of the solvent from the carbon fiber mesh. The radiation drying device enables rapid and uniform drying of the resin solution in the fiber mesh, quickly removing some of the solvent and reducing resin migration, thus maintaining the resin's position within the fiber. The carbon fiber mesh is uniformly distributed within the fiber mesh, and then completely dried using a hot air penetration oven. Simultaneously, it is heated to a sufficient temperature to completely cross-link and cure the adhesive (resin). The hot air penetration oven completely removes any remaining solvent from the fiber mesh. The hot air penetration further loosens the arrangement of the fibers, and the temperature of the hot air causes the resin remaining at the fiber interlacing points to cross-link and cure, thus strengthening the overall carbon fiber mesh. In summary, through the synergistic effect of each step, the resulting carbon fiber mesh (mesh core) possesses high bulk and high porosity, along with certain strength and durability. In the subsequent hot-pressing and lamination stage, by controlling the compression ratio and the proportion of phenolic resin to the fiber mesh, the carbon fiber insulation felt product can achieve low density, high porosity, and high insulation performance.

[0038] In a preferred embodiment, the double-net clamping coating equipment applies coating to the upper and lower surfaces of the shaped carbon fiber mesh using a coat hanger-type solution dispensing device and a flipping mechanism.

[0039] The double-net clamping resin coating equipment uses a coat hanger-type solution distribution device and a flipping mechanism to apply resin solution to the upper and lower surfaces of the fiber web, which helps to avoid uneven dispersion of the resin solution in the thick fiber web.

[0040] In this invention, the shaped carbon fiber mesh is fed into a double-mesh clamping adhesive coating device by a transmission pressure roller under the action of a speed ratio of no more than 5% between the front and rear conveying rollers.

[0041] The shaped carbon fiber mesh is fed into a coating equipment equipped with a coat hanger-type solution dispensing device by a transmission pressure roller under extremely low tension caused by a speed ratio of no more than 5% between the front and rear conveying rollers (this tension is controlled by the transmission speed difference, which is maintained at 0-5%).

[0042] The structure of the hanger-type solution dispensing device is shown in the figure. Figure 1 and Figure 2It includes a resin solution inlet pipe 1, a gas inlet 2, and a solution channel 3. The resin solution enters the distribution device through the resin solution inlet pipe 1, and the gas enters the distribution device through the gas inlet 2. In the distribution device, the resin solution is evenly pressed into each horizontally adjacent solution channel 3 by the gas pressure generated by the gas. Under the action of gravity, the resin solution is sprayed onto the surface of the carbon fiber mesh in a liquid flow, thereby achieving the purpose of resin coating.

[0043] In a preferred embodiment, the resin used for lamination includes, but is not limited to, phenolic resin.

[0044] In a preferred embodiment, the method for removing excess adhesive from the carbon fiber mesh includes, but is not limited to, removing excess adhesive by a vacuum suction device.

[0045] Removing excess adhesive using a vacuum liquid removal device makes it easier to control the resin content on the carbon fiber mesh, and thus better control the weight and density of the final product.

[0046] In this invention, the radiation drying device heats the inner and outer layers of the carbon fiber mesh simultaneously through infrared radiation, achieving rapid and uniform drying, which helps to reduce the migration of the resin solution.

[0047] In a preferred embodiment, the temperature of the radiant drying device can be 60°C-80°C, with typical but non-limiting temperatures such as 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, and 80°C. This temperature is more conducive to the rapid and uniform drying of the resin solution and to reducing the migration phenomenon of the resin solution, so that the resin is evenly distributed in the fiber web.

[0048] In a preferred embodiment, the temperature program of the hot air permeation oven can be to heat from 80°C to 180°C, hold at that temperature, and then cool down to 60°C.

[0049] The temperature of the hot air penetration oven can be gradually increased from 80℃ to 180℃ and maintained for a period of time, and then the temperature is gradually reduced to 60℃. This drying stage can not only completely dry the carbon fiber mesh to remove the solvent, but also when the temperature rises to 110℃, the phenolic resin begins to cure, and the phenolic resin molecules cross-link with each other, thereby completing the reinforcement of the fiber mesh.

[0050] In this invention, the carbon fiber mesh is shaped by means of heat setting, including but not limited to heat setting; wherein, the heat setting temperature can be 180℃-220℃, and typical but non-limiting temperatures are, for example, 180℃, 190℃, 200℃, 210℃, and 220℃, which are more conducive to further improving the shaping effect of the carbon fiber mesh.

[0051] A typical preparation method for a high-loft carbon-carbon thermal insulation rigid felt, the process of which is as follows: Figure 3 This includes the following steps:

[0052] Short carbon fiber: Use mixed short carbon wires with a length of 40mm-120mm. The mass proportion of short carbon wires with a chopped length of less than 60mm should be less than 50%, and the mass proportion of short carbon wires with a chopped length of more than 100mm should be not less than 10%. It is preferred to use short carbon wires with a length of 70mm-80mm.

[0053] It should be noted that the present invention uses short carbon filaments of different lengths for mixing, which can give the fiber web, the mesh core and its carbon-carbon thermal insulation felt sufficient strength, processability and durability. In addition, to a certain extent, carbon filaments with a fiber length of <60mm can be replaced with carbon fiber preforms and soft felt edge materials that have been crushed and loosened, which helps to reduce production costs.

[0054] Opening: Short carbon wires of different lengths are placed in a mixing container and mechanically stirred to achieve preliminary mixing of short carbon wires of different lengths;

[0055] The pre-mixed carbon filaments are poured onto the drive curtain of the opening machine and fed into the multi-roller opening machine through the metal impurity remover to open and mix the chopped carbon filaments.

[0056] Airflow forming: After the fibers are opened by a multi-roller opener, they are sent into the cotton box by high-speed airflow. The opened fiber bundles are then lifted upward by the conveying nail curtain to the cotton leveling roller and the cotton dropping roller.

[0057] After being homogenized and metered by the cotton leveling roller, the fiber clumps are then peeled off by the cotton drop roller and transferred to the vibrating plate. The vibration of the vibrating plate causes the fiber clumps to fall and be evenly stacked on the conveyor curtain to form a continuous fiber clump.

[0058] After being precisely metered, the continuous fiber bundles are fed into the high-speed cylinder by the feed roller. The cylinder combs the fiber bundles at high speed to form a fiber web. The fiber web is adsorbed by the air curtain with negative pressure and stripped from the high-speed cylinder to form a highly disordered, isotropic, continuous carbon fiber web with a certain strength.

[0059] The carbon fiber mesh is fed into the reciprocating mesh laying machine via a conveyor curtain;

[0060] Composite reinforcement: After the carbon fiber mesh passes through the feeding curtain, annular curtain, reciprocating curtain, and output clamping roller of the reciprocating web laying machine (web laying device 100) in sequence, it is laid in a "Z" pattern according to the parameter settings. By setting the process parameters of the web laying machine's web laying layer number and web laying width, the thickness, areal density, and density can be increased to meet the product design requirements, with the highest areal weight reaching 3000 g / m². 2 ;

[0061] It should be noted that this invention combines air-laid web formation with a reciprocating web-laying machine. Building upon the isotropic mechanical strength of the air-laid carbon fiber web, the reciprocating web-laying machine further layers the resulting fiber web, increasing its thickness, areal density, and tensile strength. Furthermore, it reduces the difference in mechanical properties between the longitudinal and transverse directions of the fiber web, thereby improving the uniformity of carbon fiber monofilament distribution. This achieves the goal of uniform composite strength and density of the carbon-carbon insulation felt. Through air-laid web formation, this invention can produce web products with extremely high areal density, reaching up to 3000 g / m². 2 The process of processing carbon fiber mesh tires into finished products has been optimized, which helps to reduce production costs.

[0062] The laid carbon fiber mesh is fed into a pair of hot heat rollers 300 through the transmission curtain 200. The corresponding hot heat roller spacing is set according to the product thickness. The carbon fiber mesh is hot heat-set at 180℃-220℃. The output speed is set to 100%-110% of the carbon fiber mesh feeding speed. The required thickness of the product is initially controlled and the carbon fiber mesh is conveyed backward.

[0063] After heat setting, the carbon fiber mesh is fed into the first resin solution coating zone 400 equipped with a hanger-type solution dispensing device 403 via the first transmission pressure roller 402 under a speed ratio of no more than 5% between the front and rear conveyor rollers (i.e., under extremely low tension). Figure 4 ;

[0064] The viscosity of the phenolic resin solution is adjusted to 500cp-1000cp using a solvent and a fast-curing phenolic resin (the mass ratio of solvent to phenolic resin is 1:2). The phenolic resin solution is uniformly pressed into the solution channels 3 of each horizontal adjacent 100mm in the solution distribution device 403 under the action of air pressure (0.05Mpa-0.2Mpa). Under the action of gravity, the phenolic resin solution is poured onto the surface of the carbon fiber mesh in a liquid flow, thereby realizing one-time resin coating.

[0065] The carbon fiber mesh that has completed the first coating is lifted upward and rotated horizontally 180° under the drive of the traction roller, the clamping curtain 404 and the relatively small speed ratio of the front and rear traction rollers, and then sent into the second resin solution coating zone 600 for a second coating via the transmission roller 500.

[0066] The second resin solution coating zone 600 has the same configuration as the first resin solution coating zone, but the overall position of the coat hanger-type solution dispensing device in the second resin solution coating zone 600 is offset by 50mm along the product width direction.

[0067] It should be noted that the adjacent distance, air pressure, and relative offset distance of the solution channels inside the hanger-type solution distribution device can be adjusted according to the actual product width, thickness, and basis weight. At the same time, metal support rollers 401 with polytetrafluoroethylene coating can be used to support the carbon fiber mesh in the glue coating area.

[0068] After the second coating (i.e. double coating), the carbon fiber mesh is held by the clamping curtain and driven forward by the second transmission pressure roller 601, so that the surface of the fiber mesh is smoothed by the fibers brought out by the transmission, and the phenolic resin solution is accelerated to flow and level and be conveyed forward to the vacuum liquid suction device 700.

[0069] After the carbon fiber mesh is removed by a vacuum liquid removal device 700, it is then dried. The drying process consists of two parts: pre-drying and main drying.

[0070] The pre-drying section uses a radiation drying device 800 to dry the carbon fiber mesh and remove some of the solvent. The inner and outer layers of the carbon fiber mesh are heated simultaneously by infrared radiation to reduce the migration of the phenolic resin solution. The temperature of this stage is set to 60℃-80℃.

[0071] The main drying section uses a hot air penetration oven 900 to dry the carbon fiber mesh and remove the remaining solvent. The temperature program in this stage starts from 80℃, gradually increases to 180℃ and maintains it for a period of time, and then gradually decreases to 60℃. This not only dries the carbon fiber mesh completely, but also allows the (fast-curing) phenolic resin to begin to cure when the temperature rises to 110℃. The phenolic resin molecules cross-link with each other, which strengthens the overall carbon fiber mesh.

[0072] Cutting and material preparation: Cut the reinforced carbon fiber mesh according to the specifications and dimensions of the product blank, and prepare the required number of mesh sheets for carbon carbon insulation felt based on weight and thickness.

[0073] Lamination and hot pressing: Phenolic resin is sprayed onto the cut carbon fiber mesh (mesh) according to the order requirements. After spraying evenly on the surface of each mesh, the mesh is laid up and sent into a hot press for hot pressing. The mesh is hot pressed with a small compression ratio to achieve bonding between the meshes and complete the production of the curing felt.

[0074] Carbonization treatment: The cured felt is placed in a carbonization furnace for carbonization treatment, so that the phenolic resin in the cured felt is carbonized in a high-temperature environment;

[0075] After carbonization, the cured felt becomes carbon felt;

[0076] High-temperature treatment: The carbon felt is placed in a high-temperature furnace and treated at 2300℃ to obtain carbon-carbon thermal insulation hard felt.

[0077] In summary, this invention, through the combination of phenolic resin solution, double-net clamping coating equipment, radiant drying device, and hot air penetration oven, imparts a certain strength to the mesh while retaining its high bulkiness, high porosity, and high specific surface area, and enables the mesh thickness to reach over 20mm. The manufacturing process of this invention reduces the needle-punching process required in traditional carbon-carbon insulating felt preparation, improving production efficiency, enabling quantitative control of resin usage, and reducing production costs. Since the needle-punching composite step is eliminated, the number of Z-axis through-distributed carbon filaments within the carbon-carbon insulating felt is reduced, significantly decreasing heat transfer channels and thus improving the insulation performance of the carbon-carbon insulating felt.

[0078] In summary, through the synergistic coordination of each step and its parameters, the preparation method of this invention can produce materials with a density as low as 0.08 g / cm³. 3 The carbon-carbon thermal insulation felt can increase the porosity of the carbon-carbon thermal insulation felt, effectively reduce the thermal conductivity of the carbon-carbon thermal insulation felt, and thus significantly improve the thermal insulation performance of the carbon-carbon thermal insulation felt.

[0079] According to a second aspect of the present invention, a carbon-carbon thermal insulation rigid felt prepared by any of the above-described preparation methods is provided.

[0080] The high-loft carbon-carbon thermal insulation felt provided by this invention has low density, high porosity, and low thermal conductivity, thus exhibiting excellent thermal insulation performance.

[0081] In this invention, the density of the carbon-carbon thermal insulation felt can be 0.08 g / cm³. 3 -0.16g / cm 3 The porosity of carbon-carbon thermal insulation rigid felt can be 91.12%-95.56%; the bulkiness of carbon-carbon thermal insulation rigid felt can be 6.25cm. 3 / g-12.5cm 3 / g.

[0082] In a preferred embodiment, the thermal conductivity of the carbon-carbon insulating felt can be 0.05-0.1.

[0083] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0084] Example 1

[0085] A method for preparing a high-loft carbon-carbon thermal insulation rigid felt includes the following steps:

[0086] (a) Short carbon fiber: Short carbon wire with a length of 40mm-120mm is used. The mass proportion of short carbon wire with a chopped length of less than 60mm is less than 50%, and the mass proportion of short carbon wire with a chopped length of more than 100mm is not less than 10%.

[0087] (b) Opening: Place the short carbon wires of different lengths into a mixing container and achieve preliminary mixing of the short carbon wires of different lengths by mechanical stirring;

[0088] The carbon filaments that have completed the initial mixing are poured onto the drive curtain of the opening machine. After being processed by the metal impurity remover, they are fed into the multi-roller opening machine to loosen and mix the chopped carbon filaments.

[0089] (c) Airflow forming: After the fibers are opened by a multi-roller opener, they are sent into the cotton box by high-speed airflow. The opened fiber bundles are then lifted upward by the conveying nail curtain to the cotton leveling roller and the cotton dropping roller.

[0090] After being homogenized and metered by the cotton leveling roller, the fiber clumps are then peeled off by the cotton drop roller and transferred to the vibrating plate. The vibration of the vibrating plate causes the fiber clumps to fall and be evenly stacked on the conveyor curtain to form a continuous fiber clump.

[0091] After being precisely metered, the continuous fiber bundles are fed into the high-speed cylinder by the feed roller. The cylinder combs the fiber bundles at high speed to form a fiber web. The fiber web is adsorbed by the air curtain with negative pressure and stripped from the high-speed cylinder to form a highly disordered, isotropic, continuous carbon fiber web with a certain strength.

[0092] The carbon fiber mesh is fed into the reciprocating mesh laying machine via a conveyor curtain;

[0093] (d) Composite reinforcement: After the carbon fiber mesh passes through the feeding curtain, annular curtain, reciprocating curtain and output clamping roller of the reciprocating mesh laying machine (mesh laying device 100) in sequence, it is laid in a "Z" shape according to the parameter setting value. By setting the process parameters of the number of mesh laying layers and the mesh laying width of the mesh laying machine, the thickness, surface density and density are increased to meet the requirements of the product design.

[0094] The laid carbon fiber mesh is fed into a pair of hot heat rollers 300 through the transmission curtain 200. The spacing between the hot heat rollers is set according to the product thickness. The carbon fiber mesh is hot heat-set at 200℃. The output speed is set to 105% of the carbon fiber mesh feeding speed. The required thickness of the product is initially controlled and the carbon fiber mesh is conveyed backward.

[0095] After the heat setting is completed, the carbon fiber mesh is fed into the first resin solution coating zone 400 with a hanger-type solution distribution device 403 through the first transmission pressure roller 402 under the action of the front and rear conveying rollers with a speed ratio of no more than 5% (i.e. under extremely low tension).

[0096] The viscosity of the phenolic resin solution is adjusted to 800cp using a solvent and a fast-curing phenolic resin (the mass ratio of solvent to phenolic resin is 1:2). The phenolic resin solution is uniformly pressed into the solution channels 3 of each horizontal adjacent 100mm in the solution distribution device 403 under the action of air pressure (0.1Mpa). Under the action of gravity, the phenolic resin solution is sprayed onto the surface of the carbon fiber mesh in a liquid flow, thereby realizing one-time resin coating.

[0097] The carbon fiber mesh that has completed the first coating is lifted upward and rotated horizontally 180° under the drive of the traction roller, the clamping curtain 404 and the relatively small speed ratio of the front and rear traction rollers, and then sent into the second resin solution coating zone 600 for a second coating via the transmission roller 500.

[0098] The second resin solution coating zone 600 has the same configuration as the first resin solution coating zone, but the overall position of the coat hanger-type solution dispensing device in the second resin solution coating zone 600 is offset by 50mm along the product width direction.

[0099] In the coating zone, metal support rollers 401 with a polytetrafluoroethylene coating are used to support the carbon fiber mesh.

[0100] After the second coating (i.e. double coating), the carbon fiber mesh is held by the clamping curtain and driven forward by the second transmission pressure roller 601, so that the surface of the fiber mesh is smoothed by the fibers brought out by the transmission, and the phenolic resin solution is accelerated to flow and level and be conveyed forward to the vacuum liquid suction device 700.

[0101] After the carbon fiber mesh is removed by a vacuum liquid removal device 700, it is then dried. The drying process consists of two parts: pre-drying and main drying.

[0102] The pre-drying section uses a radiation drying device 800 to dry the carbon fiber mesh and remove some of the solvent. The inner and outer layers of the carbon fiber mesh are heated simultaneously by infrared radiation to reduce the migration of the phenolic resin solution. The temperature of this stage is set to 70°C.

[0103] The main drying section uses a hot air penetration oven 900 to dry the carbon fiber mesh and remove the remaining solvent. The temperature program in this stage starts from 80℃, gradually increases to 180℃ and maintains it for a period of time, and then gradually decreases to 60℃. This not only dries the carbon fiber mesh completely, but also allows the (fast-curing) phenolic resin to begin to cure when the temperature rises to 110℃. The phenolic resin molecules cross-link with each other, which strengthens the overall carbon fiber mesh.

[0104] (e) Cutting and material preparation: Cut the reinforced carbon fiber mesh according to the specifications and dimensions of the product blank, and prepare the required number of mesh pieces for carbon carbon insulation felt based on weight and thickness.

[0105] (f) Lamination and hot pressing: The cut carbon fiber mesh (mesh) is sprayed with phenolic resin according to the order requirements. After spraying evenly on the surface of each mesh, the mesh is laid up and sent into a hot press for hot pressing. The mesh is hot pressed with a small compression ratio to achieve bonding between the meshes and complete the production of the curing felt.

[0106] (g) Carbonization treatment: The cured felt is placed in a carbonization furnace for carbonization treatment, so that the phenolic resin in the cured felt is carbonized in a high-temperature environment.

[0107] After carbonization, the cured felt becomes carbon felt;

[0108] (h) High temperature treatment: The carbon felt is placed in a high temperature furnace and treated at 2300℃ to obtain carbon-carbon thermal insulation hard felt.

[0109] Example 2

[0110] The difference between this embodiment and Embodiment 1 is that the hanger-type solution dispensing device is replaced with an impregnation tank in this embodiment;

[0111] The remaining steps and process parameters are the same as in Example 1, resulting in carbon-carbon thermal insulation hard felt.

[0112] Compared with Example 1, the drawback of this example is that the impregnation tank adopts a saturated impregnation method, which uses more resin, resulting in higher production costs, and it is also impossible to accurately control the resin content in the product.

[0113] Example 3

[0114] The difference between this embodiment and Embodiment 1 is that in this embodiment, phenolic resin is replaced with asphalt in the resin coating area;

[0115] The remaining steps and process parameters are the same as in Example 1, resulting in carbon-carbon thermal insulation hard felt.

[0116] Compared with Example 1, the drawbacks of this example are that, due to the poor fluidity of the asphalt, the coating equipment needs to be heated, and the asphalt is prone to uneven distribution after coating; at the same time, the asphalt has a poor wetting effect on the carbon fiber mesh, and the product is prone to delamination after coating; in addition, the asphalt has a high impurity content, resulting in high ash content in the produced product.

[0117] Example 4

[0118] The difference between this embodiment and Embodiment 1 is that the vacuum liquid suction device is replaced with a liquid rolling roller in this embodiment;

[0119] The remaining steps and process parameters are the same as in Example 1, resulting in carbon-carbon thermal insulation hard felt.

[0120] Compared with Example 1, the drawback of this example is that a certain roller pressure is required to obtain a better residual adhesive removal effect, which can easily cause changes in product thickness; at the same time, during the residual adhesive removal process, the roller pressure can easily cause wrinkles on the product surface; in addition, the surface of the roller is prone to sticking to the resin-containing fiber web, resulting in fuzzing on the product surface.

[0121] Comparative Example 1

[0122] The difference between this comparative example and Example 1 is that the radiant drying device is replaced with a contact metal drying cylinder in this comparative example.

[0123] The remaining steps and process parameters are the same as in Example 1, resulting in carbon-carbon thermal insulation hard felt.

[0124] Compared with Example 1, the shortcomings of this comparative example are that the resin will migrate, resulting in uneven resin distribution, which leads to production abnormalities in subsequent production and processing; the surface of the drying cylinder has a certain curvature, which can easily cause damage to the internal structure of the fiber web; and wrinkles are easily generated on the product surface.

[0125] Comparative Example 2

[0126] The difference between this comparative example and Example 1 is that the step of removing the residual adhesive on the carbon fiber mesh was not performed in this comparative example; that is, the carbon fiber mesh after the second coating was directly dried.

[0127] The remaining steps and process parameters are the same as in Example 1, resulting in carbon-carbon thermal insulation hard felt.

[0128] Compared with Example 1, the drawback of this comparative example is that it not only reduces the drying efficiency, but also easily causes resin migration during the drying process, resulting in uneven resin distribution and affecting the yield of subsequent processing. At the same time, due to the excessive resin content in the mesh, there is more residual carbon in the hard felt after carbonization, which leads to an increase in the overall product density, which increases production costs and reduces the product's heat insulation performance.

[0129] Comparative Example 3

[0130] The difference between this comparative example and Example 1 is that no radiant drying device was used in this comparative example. That is, after the carbon fiber mesh removes the excess adhesive, the solvent is completely dried directly through a hot air penetration oven.

[0131] The remaining steps and process parameters are the same as in Example 1, resulting in carbon-carbon thermal insulation hard felt.

[0132] Compared with Example 1, the drawback of this comparative example is that, due to the large resin content in the mesh, resin migration is prone to occur during direct drying, resulting in uneven resin distribution. It is also prone to bursting during the curing process and delamination after carbonization, leading to a reduction in production yield.

[0133] Comparative Example 4

[0134] The difference between this comparative example and Example 1 is that the hot air penetration oven is replaced with a jet convection oven in this comparative example.

[0135] The remaining steps and process parameters are the same as in Example 1, resulting in carbon-carbon thermal insulation hard felt.

[0136] Compared with Example 1, the shortcomings of this comparative example are that the jet convection oven uses a single-layer or multi-layer flat drying chamber, which results in relatively large migration of the resin during the drying process; at the same time, the drying efficiency of the jet convection oven for thick fiber webs is relatively low, affecting production efficiency; in addition, the drying uniformity of the jet convection oven is relatively poor, which easily leads to inconsistent drying effects of the fiber web, with the outer layer being over-dried while the inner layer does not meet the process requirements.

[0137] In summary, the preparation method of this invention combines phenolic resin solution, double-net clamping coating equipment, radiant drying device, and hot air penetration oven. This approach imparts a certain strength to the mesh while retaining its high bulkiness, high porosity, and high specific surface area, and allows for a mesh thickness of over 20mm. This invention effectively improves production efficiency, allows for quantitative control of resin usage, thus reducing production costs. Furthermore, it reduces the number of Z-axis through-distributed carbon filaments within the carbon-carbon insulating felt, significantly decreasing heat transfer channels and effectively enhancing the insulation performance of the carbon-carbon insulating felt.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high-loft carbon-carbon thermal insulation rigid felt, characterized in that, Includes the following steps: (a) After the carbon fiber mesh passes through the feeding curtain, annular curtain, reciprocating curtain and output clamping roller of the reciprocating web laying machine in sequence, it is laid in a "Z" shape according to the parameter setting value. By setting the process parameters of the web laying machine, the thickness, surface density and density are increased to meet the requirements of the product design. The laid-up carbon fiber mesh is heat-set to obtain the shaped carbon fiber mesh. The temperature for heat setting is 180℃-220℃; The output speed during the heat setting process is 100%-110% of the carbon fiber mesh feeding speed; The shaped carbon fiber mesh is first coated with adhesive on both sides using a double-mesh clamping adhesive coating equipment, and then the excess adhesive on the carbon fiber mesh is removed to control the adhesive content. Then, it is dried by a radiation drying device to remove some of the solvent from the carbon fiber mesh. After that, it is dried by a hot air penetration oven to remove the remaining solvent from the carbon fiber mesh, while the adhesive undergoes cross-linking and curing to obtain a reinforced carbon fiber mesh. The dual-net clamping coating equipment applies coating to the upper and lower surfaces of the shaped carbon fiber mesh through a coat hanger-type solution dispensing device and a flipping mechanism. The shaped carbon fiber mesh is fed into a double-mesh clamping adhesive coating equipment by a transmission pressure roller under the action of a speed ratio of no more than 5% between the front and rear conveying rollers. The resin used in the coating process includes phenolic resin; The method for removing excess adhesive from the carbon fiber mesh includes removing excess adhesive using a vacuum liquid suction device; (b) The reinforced carbon fiber mesh obtained in step (a) is sequentially subjected to layup hot pressing and carbonization treatment to obtain the carbon-carbon thermal insulation felt.

2. The preparation method according to claim 1, characterized in that, The temperature of the radiant drying device is 60℃-80℃.

3. The preparation method according to claim 2, characterized in that, The temperature program of the hot air penetration oven is to raise the temperature from 80°C to 180°C, hold it at that temperature, and then lower it to 60°C.

4. A carbon-carbon thermal insulation rigid felt prepared by the preparation method according to any one of claims 1-3.

5. The carbon-carbon thermal insulation rigid felt according to claim 4, characterized in that, The density of the carbon-carbon thermal insulation rigid felt is 0.08 g / cm³-0.16 g / cm³; The porosity of the carbon-carbon thermal insulation felt is 91.12%-95.56%; The bulkiness of the carbon-carbon thermal insulation felt is 6.25 cm. 3 / g-12.5cm 3 / g.

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