Composite thermal insulation hard felt and method for manufacturing the same

Abstract

The application discloses a composite thermal insulation hard felt and a preparation method thereof, and belongs to the field of thermal insulation materials. The composite thermal insulation hard felt comprises a carbon fiber felt body and a carbon-carbon composite sheet. The carbon-carbon composite sheet is attached to the surface of the carbon fiber felt body through an adhesive. The adhesive is made of components containing the following components by weight percentage: furan resin 20-25%; silicon modified phenolic resin 5-8%; graphite powder 5-8%; carbon powder 15-20%; silicon carbide powder 1-2%; dispersing agent 2-3%; carbonization aid 1-2%; and the balance is solvent. The application has the effect of improving the long-term effectiveness of the thermal insulation hard felt in an ultrahigh-temperature environment.

Description

Technical Field

[0001] This application relates to the field of thermal insulation materials, and in particular to a composite thermal insulation rigid felt and its preparation method. Background Technology

[0002] The temperature of the silicon carbide crystal pulling thermal environment can reach over 2300℃, making the insulation materials used crucial. Insulation materials not only ensure the safety and reliability of equipment operation but also significantly improve production efficiency and reduce costs. Currently, commonly used insulation materials mainly include traditional carbon fiber rigid insulation felt. Carbon fiber rigid insulation felt is generally manufactured through special processes including bonding, curing, shaping, carbonization, and high-temperature treatment. Due to its excellent thermal insulation properties, carbon fiber rigid insulation felt is widely used, thereby reducing heat loss and lowering operating power.

[0003] However, when used for a long time in ultra-high temperature environments, traditional carbon fiber insulation felt is easily eroded by high-temperature steam in the thermal field, which leads to damage to the carbon fiber insulation felt, uneven local temperature control in the thermal field, reduced insulation effect, and shortened life of the insulation felt. Summary of the Invention

[0004] To improve the long-term effectiveness of thermal insulation rigid felt in ultra-high temperature environments, this application provides a composite thermal insulation rigid felt and its preparation method.

[0005] Firstly, the composite thermal insulation rigid felt provided in this application adopts the following technical solution: A composite thermal insulation rigid felt includes a carbon fiber felt body and a carbon-carbon composite sheet, wherein the carbon-carbon composite sheet is attached to the surface of the carbon fiber felt body by an adhesive, the adhesive being made of components comprising the following weight percentages: 20-25% furan resin; Silicon-modified phenolic resin 5-8%; Graphite powder 5-8%; 15-20% toner; 1-2% silicon carbide powder; Dispersant 2-3%; Carbonization aid 1-2%; The remainder is solvent.

[0006] By adopting the above technical solution, the carbon-carbon composite sheet is a thin sheet formed from carbon-carbon composite materials. Due to the strong affinity between carbon atoms, it has good stability and can resist the erosion of high-temperature steam in the silicon carbide thermal field, thus protecting the carbon fiber felt.

[0007] The binder enables the carbon-carbon composite sheet to form a high degree of bonding with the carbon fiber felt, making it difficult to separate at high temperatures. Silicon-modified phenolic resin introduces organosilicon, resulting in excellent high-temperature resistance. This allows the phenolic resin and furan resin to form a stable cross-linked network. Graphite powder, carbon powder, and silicon carbide are incorporated into this cross-linked network, acting as fillers, lubricants, and dispersants. This strengthens the bond between the binder and the carbon-carbon composite sheet and the carbon fiber felt, while also resisting the erosion of high-temperature steam. This further improves the overall structural stability of the thermal insulation felt, ensuring its long-term stability even at ultra-high temperatures and extending its overall service life.

[0008] Optionally, the carbon-carbon composite sheet is made of carbon fiber cured with resin, with a thickness of 3±1 mm and a density of 1.5~1.8 g / cm³. 3 .

[0009] By adopting the above technical solution, the carbon-carbon composite sheet has high density, strong barrier ability against high-temperature gases, and high corrosion resistance.

[0010] Optionally, the silicon-modified phenolic resin is a long-chain silane coupling agent-modified phenolic resin. The long-chain silane coupling agent is formed by reacting a long-chain ester with an aminosilane coupling agent. The long-chain silane coupling agent is added during the synthesis of the phenolic resin to obtain the long-chain silane coupling agent-modified phenolic resin.

[0011] By adopting the above technical solution, the long-chain silane coupling agent introduces organosilicon into the phenolic resin, and at the same time, it also introduces aliphatic long carbon chains into the phenolic resin. By utilizing the flexibility of the aliphatic long carbon chains and their entanglement with the phenolic chain segments, a synergistic toughening crosslinking is formed. After curing, the stability between the interface of the carbon fiber felt and the interface of the carbon-carbon composite sheet is improved, thereby strengthening the adhesion, increasing the adhesion life, and thus improving the service life of the thermal insulation felt at ultra-high temperatures.

[0012] Optionally, the long-chain ester is selected from one or both of butyl dodecanoate and butyl tetradecanoate.

[0013] By adopting the above technical solution and selecting the above two long-chain esters, the flexible winding effect of long carbon chains can be utilized, and the polarity matching of molecular structure can be avoided due to excessively long aliphatic carbon chains. Therefore, the selection of butyl dodecanoate and butyl tetradecanoate can effectively improve the stability of thermal insulation felt.

[0014] Optionally, the aminosilane coupling agent is selected from one or both of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0015] Optionally, the molar ratio of the long-chain ester to the aminosilane coupling agent is 1:1.

[0016] Optionally, the dispersant is selected from one or more of diethylene glycol butyl ether, propylene glycol methyl ether, and triethylene glycol monobutyl ether.

[0017] By adopting the above technical solution, the above-mentioned dispersants can enable insoluble carbon powder, graphite powder and silicon carbide to be uniformly dispersed in the solvent, so as to play the filling role of carbon powder, graphite powder and silicon carbide.

[0018] Optionally, the carbonization aid is selected from cellulose and / or cellulose derivatives.

[0019] By adopting the above technical solution, cellulose can promote the high-temperature carbonization process, thereby promoting the formation of a dense cross-linked network structure and further improving the stability of the thermal insulation felt.

[0020] Optionally, the carbon fiber felt is made by coating carbon fiber soft felt with silicon-modified phenolic resin, and the mass ratio of the carbon fiber soft felt to the silicon-modified phenolic resin is 1:(1~1.5).

[0021] By adopting the above technical solution, silicon-modified phenolic resin is used to coat carbon fiber soft felt, enabling the structure of the carbon fiber felt to also withstand high temperatures, thereby improving the overall high-temperature stability of the thermal insulation hard felt.

[0022] Optionally, the carbon powder is amorphous and lacks a long-range ordered crystal structure. The graphite powder has a layered structure and exhibits a hexagonal crystal system.

[0023] Optionally, the solvent may be methanol or ethanol.

[0024] Secondly, the preparation method of the composite thermal insulation rigid felt provided in this application adopts the following technical solution: The solvent, furan resin and silicon-modified phenolic resin are mixed and stirred, then carbon powder, graphite powder and silicon carbide are added and mixed and stirred, and then dispersant and carbonization aid are added and mixed and stirred to obtain the binder. An adhesive is applied to the surface of the carbon-carbon composite sheet, and the carbon fiber soft felt is attached to the carbon-carbon composite sheet and baked to obtain a preliminary composite hard felt. The preliminary composite rigid felt is placed in an environment of not less than 2000℃ for vacuum high-temperature carbonization treatment to obtain composite thermal insulation rigid felt.

[0025] By adopting the above technical solution, after mixing the resin and solvent, toner, graphite powder, and silicon carbide are added. Toner is the main filler, which can increase the residual carbon content of the binder and enhance its adhesion at high temperatures. Graphite powder and silicon carbide also act as fillers, and graphite powder can increase the lubricity of the binder, allowing it to be better coated onto the surface of the carbon-carbon composite sheet. The high-temperature resistance of silicon carbide itself can enhance the high-temperature stability of the binder. Due to the insolubility of toner, graphite powder, and silicon carbide, a dispersant is added in a subsequent step to improve the dispersibility of toner, graphite powder, and silicon carbide.

[0026] After the carbon fiber soft felt is attached to the carbon-carbon composite sheet, it is baked to achieve preliminary shaping. The preliminary composite hard felt after preliminary shaping is carbonized at high temperature to form a carbon fiber felt body. At the same time, the carbon fiber felt body and the carbon-carbon composite sheet are tightly bonded, thereby resisting the erosion of high temperature steam and extending the service life of the thermal insulation hard felt.

[0027] Optionally, under the protection of an inert gas, the aminosilane coupling agent, long-chain ester, and organic solvent are mixed and heated to 80-90°C to react. After the reaction is completed, the solvent is removed by negative pressure distillation to obtain the long-chain silane coupling agent. The long-chain silane coupling agent and ethanol solution were mixed, the pH was adjusted to weakly alkaline, and hydrolysis was performed to obtain a hydrolyzed mixture. Phenol and a portion of the catalyst solution are mixed and heated to 60–70°C for 20–40 min. Then, a portion of formaldehyde is added and heated to 85–90°C for 1–1.5 h. The remaining catalyst solution and formaldehyde are then added, and the hydrolysis mixture is added dropwise to the reaction solution. The reaction continues for 1–2 h. The pH is then adjusted to neutral, and the mixture is dehydrated under vacuum to obtain silicon-modified phenolic resin.

[0028] By adopting the above technical solution, the ester group of the long-chain ester reacts and bonds with the amino group in the aminosilane coupling agent to form a long-chain silane coupling agent. The long-chain silane coupling agent is then grafted during the synthesis of phenolic resin to achieve silicon modification of phenolic resin and improve the high-temperature stability of phenolic resin.

[0029] Optionally, the organic solvent is a high-boiling-point alcohol, preferably n-butanol.

[0030] Optionally, the molar ratio of formaldehyde to phenol is 1:(1.2 to 1.4).

[0031] Optionally, the mass ratio of the long-chain silane coupling agent to phenol is (0.2-0.25):1.

[0032] Optionally, the catalyst solution is a NaOH solution, wherein the molar ratio of NaOH to phenol is (0.02-0.03):1.

[0033] Optionally, the method for preparing the carbon-carbon composite sheet includes the following steps: Short carbon fibers are formed by airflow and then needle-punched to form a carbon fiber mesh. The carbon fiber mesh is then placed in a mold, and furan resin is added to the mold. After pressing the mold, it is pre-cured at 170-180℃ for 2-3 hours, then demolded, and placed in a vacuum furnace at 2000-2200℃ for 4-5 hours to finally obtain a carbon-carbon composite sheet.

[0034] In summary, this application has the following beneficial effects: 1. This application incorporates a carbon-carbon composite sheet on top of a carbon fiber felt body. The carbon-carbon composite sheet is a thin sheet formed from carbon-carbon composite materials. Due to the strong affinity between carbon atoms, it exhibits excellent stability and can resist the erosion of high-temperature steam in a silicon carbide thermal field, protecting the carbon fiber felt body. The binder enables the carbon-carbon composite sheet to achieve high bonding with the carbon fiber felt body, making it difficult to separate at high temperatures. Silicon-modified phenolic resin introduces organosilicon, resulting in excellent high-temperature resistance. This allows the phenolic resin and furan resin to form a stable cross-linked network. Graphite powder, carbon powder, and silicon carbide are incorporated into the cross-linked network, acting as fillers, lubricants, and dispersants, strengthening the adhesion between the binder and the carbon-carbon composite sheet and the carbon fiber felt body. This further improves the overall structural stability of the thermal insulation felt, enabling it to remain stable for extended periods even at ultra-high temperatures, thus extending its overall service life.

[0035] 2. The silicon-modified phenolic resin of this application is a phenolic resin modified with a long-chain silane coupling agent. The long-chain silane coupling agent introduces organosilicon into the phenolic resin, and at the same time introduces aliphatic long carbon chains into the phenolic resin. The flexible characteristics of aliphatic long carbon chains are used to form synergistic toughening crosslinking with phenolic chain segments. After curing, the stability between the interface of carbon fiber felt and the interface of carbon-carbon composite sheet is improved, thereby strengthening the adhesion and improving the adhesion life, and thus improving the service life of thermal insulation felt at ultra-high temperature. Attached Figure Description

[0036] Figure 1 This is a cross-sectional structural diagram of the composite thermal insulation rigid felt of Embodiment 1 of this application.

[0037] Explanation of reference numerals in the attached figures: 1. Carbon fiber felt; 2. Carbon-carbon composite sheet. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0039] Preparation Example 1 A method for preparing silicone-modified phenolic resin includes the following steps: Weigh out 331.5g of aminosilane coupling agent, 384g of long-chain ester, and 300g of organic solvent. The aminosilane coupling agent is specifically 3-aminopropyltriethoxysilane; the long-chain ester is specifically butyl dodecanoate; and the organic solvent is specifically n-butanol.

[0040] The aminosilane coupling agent, long-chain ester, and organic solvent were placed in a reaction vessel and mixed. Nitrogen gas was introduced for protection, and the mixture was heated to 80°C and refluxed for 4 hours. After the reaction was completed, the solvent was removed by negative pressure distillation to obtain the long-chain silane coupling agent.

[0041] Weigh out 403g of long-chain silane coupling agent, 400g of ethanol solution, 376g of phenol, 283g of formaldehyde solution, and 320g of catalyst solution. The concentration of the ethanol solution is 90wt%; the concentration of the formaldehyde solution is 35wt%; and the catalyst solution is a 1wt% NaOH solution.

[0042] The long-chain silane coupling agent and ethanol solution were mixed in a reaction vessel, and NaOH was added to adjust the pH to 8.5. The mixture was hydrolyzed at room temperature for 3 hours to obtain a hydrolyzed mixture.

[0043] Phenol and 50 wt% of the total catalyst solution were placed in a reaction vessel and mixed. The mixture was heated to 60°C and reacted for 40 min. Then, 40 wt% of the total formaldehyde solution was added, and the mixture was heated to 85°C and reacted for 1 h. The remaining catalyst solution and the remaining formaldehyde solution were then added. The hydrolysis mixture was then added dropwise to the reaction solution, and the reaction was continued for 1 h. Acetic acid was then added to adjust the pH to 7. Water and ethanol were removed by vacuum to obtain silicon-modified phenolic resin.

[0044] Preparation Example 2 A method for preparing silicone-modified phenolic resin includes the following steps: Weigh out 331.5g of aminosilane coupling agent, 384g of long-chain ester, and 300g of organic solvent. The aminosilane coupling agent is specifically 3-aminopropyltriethoxysilane; the long-chain ester is specifically butyl dodecanoate; and the organic solvent is specifically n-butanol.

[0045] The aminosilane coupling agent, long-chain ester, and organic solvent were placed in a reaction vessel and mixed. Nitrogen gas was introduced for protection, and the mixture was heated to 80°C and refluxed for 4 hours. After the reaction was completed, the solvent was removed by negative pressure distillation to obtain the long-chain silane coupling agent.

[0046] Weigh out 403g of long-chain silane coupling agent, 400g of ethanol solution, 470g of phenol, 306g of formaldehyde solution, and 600g of catalyst solution. The concentration of the ethanol solution is 90wt%; the concentration of the formaldehyde solution is 35wt%; and the catalyst solution is a 1wt% NaOH solution.

[0047] The long-chain silane coupling agent and ethanol solution were mixed in a reaction vessel, and NaOH was added to adjust the pH to 8.5. The mixture was hydrolyzed at room temperature for 3 hours to obtain a hydrolyzed mixture.

[0048] Phenol and 50 wt% of the total catalyst solution were placed in a reaction vessel and mixed. The mixture was heated to 70°C and reacted for 20 min. Then, 40 wt% of the total formaldehyde solution was added, and the mixture was heated to 90°C and reacted for 1.5 h. The remaining catalyst solution and the remaining formaldehyde solution were then added. The hydrolysis mixture was then added dropwise to the reaction solution, and the reaction was continued for 2 h. Acetic acid was added to adjust the pH to 7, and water and ethanol were removed under vacuum to obtain silicon-modified phenolic resin.

[0049] Preparation Example 3 Preparation method of silicon-modified phenolic resin The difference between this preparation example and Preparation Example 1 is that the long-chain ester is specifically butyl octadecyl acetate.

[0050] Preparation Example 4 A method for preparing silicone-modified phenolic resin includes the following steps: Weigh out 221g of aminosilane coupling agent, 200g of ethanol solution, 376g of phenol, 283g of formaldehyde solution, and 320g of catalyst solution. Specifically, the aminosilane coupling agent is 3-aminopropyltriethoxysilane; the ethanol solution concentration is 90wt%; the formaldehyde solution concentration is 35wt%; and the catalyst solution is a 1wt% NaOH solution.

[0051] The aminosilane coupling agent and ethanol solution were mixed in a reaction vessel, and NaOH was added to adjust the pH to 8.5. The mixture was hydrolyzed at room temperature for 3 hours to obtain a hydrolyzed mixture.

[0052] Phenol and 50 wt% of the total catalyst solution were placed in a reaction vessel and mixed. The mixture was heated to 60°C and reacted for 40 min. Then, 40 wt% of the total formaldehyde solution was added, and the mixture was heated to 85°C and reacted for 1 h. The remaining catalyst solution and the remaining formaldehyde solution were then added. The hydrolysis mixture was then added dropwise to the reaction solution, and the reaction was continued for 1 h. Acetic acid was then added to adjust the pH to 7. Water and ethanol were removed by vacuum to obtain silicon-modified phenolic resin.

[0053] Blank preparation example The preparation method of phenolic resin includes the following steps: Weigh out 376g of phenol, 283g of formaldehyde solution, and 320g of catalyst solution. The concentration of the ethanol solution is 90wt%; the concentration of the formaldehyde solution is 35wt%; and the catalyst solution is a 1wt% NaOH solution.

[0054] Phenol and 50 wt% of the total catalyst solution were placed in a reaction vessel and mixed. The mixture was heated to 60°C and reacted for 40 min. Then, 40 wt% of the total formaldehyde solution was added, and the mixture was heated to 85°C and reacted for 1 h. The remaining catalyst solution and the remaining formaldehyde solution were then added, and the reaction was continued for 1 h. Acetic acid was then added to adjust the pH to 7. Water and ethanol were removed under vacuum to obtain phenolic resin.

[0055] Preliminary Example 1 The preparation method of carbon-carbon composite sheets includes the following steps: Short-cut carbon fibers are air-formed into a web and then needle-punched to form a carbon fiber mesh. This mesh is then placed in a mold, which is filled with resin at a mass ratio of 1:1.5 (specifically, Shiyi F14 furan resin). After pressing into the mold, the mixture is pre-cured at 170℃ for 3 hours, then demolded and carbonized in a vacuum furnace at 2000℃ for 5 hours. Finally, a carbon-carbon composite sheet is obtained, with a thickness of 3±1 mm and a density of 1.5 g / cm³. 3 .

[0056] Preliminary Example 2 The preparation method of carbon-carbon composite sheets includes the following steps: Short-cut carbon fibers are air-laid into a web and then needle-punched to form a carbon fiber mesh. This mesh is then placed in a mold, which is filled with resin at a mass ratio of 1:1.7 (specifically, Shiyi F14 furan resin). After pressing into the mold, the mixture is pre-cured at 180℃ for 2 hours, then demolded and carbonized in a vacuum furnace at 2100℃ for 4 hours. The final product is a carbon-carbon composite sheet with a thickness of 3±1 mm and a density of 1.8 g / cm³. 3 .

[0057] Example 1 like Figure 1 As shown, the composite thermal insulation rigid felt includes a carbon fiber felt body 1 and a carbon-carbon composite sheet 2. The carbon-carbon composite sheet 2 is attached to the surface of the carbon fiber felt body 1 by an adhesive, and the carbon-carbon composite sheet 2 is located on the side of the carbon fiber felt body 1 facing the thermal field.

[0058] The preparation method of composite thermal insulation rigid felt includes the following steps: Carbon fiber soft felt is made by needle punching short carbon fibers into a web through airflow. The cut carbon fiber soft felt is coated with the silicon-modified phenolic resin prepared in Preparation Example 1. The mass ratio of carbon fiber soft felt to silicon-modified phenolic resin is 1:1 to obtain carbon fiber felt body.

[0059] Weigh out 2 kg of furan resin, 0.5 kg of silicon-modified phenolic resin, 0.5 kg of graphite powder, 1.5 kg of carbon powder, 0.1 kg of silicon carbide powder, 0.2 kg of dispersant, 0.1 kg of carbonization aid, and 5.1 kg of solvent. Specifically, the furan resin is Shiyi F14 furan resin; the silicon-modified phenolic resin was prepared in Preparation Example 1; the dispersant is diethylene glycol butyl ether; the carbonization aid is cellulose; and the solvent is a 95 wt% ethanol solution.

[0060] First, the solvent, furan resin and silicon-modified phenolic resin are placed in a mixing tank and mixed for 5 minutes. Then, carbon powder, graphite powder and silicon carbide are added and mixed for 3 minutes. Finally, dispersant and carbonization aid are added and mixed for 1 hour to obtain the binder.

[0061] The adhesive was applied to the surface of the carbon-carbon composite sheet prepared in Preliminary Example 1, with a coating amount of 1.1 kg / m². 2 The carbon fiber soft felt was attached to the carbon-carbon composite sheet and baked at 160℃ for 2 hours to obtain a preliminary composite hard felt.

[0062] The preliminary composite rigid felt was placed in a vacuum high-temperature furnace, and the temperature was raised to 500℃ in 7 hours, then to 1000℃ in 4 hours, then to 2000℃ in 4 hours, and held at 2000℃ for 5 hours to achieve carbonization treatment, thus obtaining the composite thermal insulation rigid felt.

[0063] Example 2 The difference between this embodiment and Embodiment 1 lies in the different preparation methods of the composite thermal insulation felt, specifically the different amounts of raw materials used in the adhesive and the different carbon-carbon composite sheets.

[0064] The composition of the mixture includes 2.5 kg of furan resin, 0.8 kg of silicon-modified phenolic resin, 0.8 kg of graphite powder, 2 kg of carbon powder, 0.2 kg of silicon carbide powder, 0.3 kg of dispersant, 0.2 kg of carbonization aid, and 3.2 kg of solvent. Specifically, the furan resin is Shiyi F14 furan resin; the silicon-modified phenolic resin was prepared according to Preparation Example 2; the dispersant is diethylene glycol butyl ether; the carbonization aid is cellulose; and the solvent is a 95 wt% ethanol solution.

[0065] Furthermore, the mass ratio of carbon fiber soft felt to silicon-modified phenolic resin is 1:1.5.

[0066] The carbon-carbon composite sheet was prepared from Preliminary Example 2.

[0067] Example 3 The difference between this embodiment and Embodiment 1 lies in the different preparation methods of the composite thermal insulation felt, specifically the different amounts of raw materials used in the adhesive.

[0068] The mixture consisted of 2.2 kg of furan resin, 0.6 kg of silicon-modified phenolic resin, 0.7 kg of graphite powder, 1.6 kg of carbon powder, 0.15 kg of silicon carbide powder, 0.24 kg of dispersant, 0.17 kg of carbonization aid, and 4.34 kg of solvent. Specifically, the furan resin was Shiyi F14 furan resin; the silicon-modified phenolic resin was prepared according to Preparation Example 1; the dispersant was diethylene glycol butyl ether; the carbonization aid was cellulose; and the solvent was a 95 wt% ethanol solution.

[0069] Example 4 The difference between this embodiment and Example 1 lies in the different preparation methods of the composite thermal insulation felt. Specifically, the silicon-modified phenolic resin is prepared by Example 3.

[0070] Example 5 The difference between this embodiment and Example 1 lies in the different preparation methods of the composite thermal insulation felt. Specifically, the silicon-modified phenolic resin is prepared by Example 4.

[0071] Comparative Example 1 Preparation method of thermal insulation rigid felt Carbon fiber soft felt is made by needle punching short carbon fiber airflow web. The cut carbon fiber soft felt is coated with phenolic resin prepared in the blank preparation example. The mass ratio of carbon fiber soft felt to phenolic resin is 1:1. Then it is baked at 160℃ for 2 hours to obtain preliminary hard felt.

[0072] The preliminary hard felt is placed in a vacuum high-temperature furnace, first heated to 500℃ for 7 hours, then heated to 1000℃ for 4 hours, then heated to 2000℃ for 4 hours, and held at 2000℃ for 5 hours to achieve carbonization treatment and obtain thermal insulation hard felt.

[0073] Comparative Example 2 The difference between this comparative example and Example 1 lies in the different preparation methods of the composite thermal insulation felt, specifically the different raw materials of the adhesive and the different carbon fiber felt body.

[0074] The preparation method of composite thermal insulation rigid felt includes the following steps: The coating agent was prepared by mixing 2 kg of silicon-modified phenolic resin, 0.5 kg of graphite powder, 1.5 kg of carbon powder, 0.1 kg of silicon carbide powder, and 0.2 kg of dispersant obtained in Preparation Example 1 for 0.5 h.

[0075] Carbon fiber felt is made by needle punching short carbon fibers into a web through airflow. The cut carbon fiber felt is then coated with a coating agent at a mass ratio of 1:1 to obtain the carbon fiber felt body.

[0076] Weigh out 2 kg of furan resin, 0.5 kg of silicon-modified phenolic resin, 0.1 kg of carbonization aid, and 5.1 kg of solvent. Specifically, the furan resin is Shiyi F14 furan resin; the silicon-modified phenolic resin is prepared from Preparation Example 1; the dispersant is diethylene glycol butyl ether; the carbonization aid is cellulose; and the solvent is a 95 wt% ethanol solution.

[0077] First, the solvent, furan resin and silicone-modified phenolic resin are placed in a mixing tank and mixed for 5 minutes. Then, carbonization aid is added and mixed for 0.5 hours to obtain the binder.

[0078] The adhesive was applied to the surface of the carbon-carbon composite sheet prepared in Preliminary Example 1, with a coating amount of 1.1 kg / m². 2 The carbon fiber soft felt was attached to the carbon-carbon composite sheet and baked at 160℃ for 2 hours to obtain a preliminary composite hard felt.

[0079] The preliminary composite rigid felt was placed in a vacuum high-temperature furnace, and the temperature was raised to 500℃ in 7 hours, then to 1000℃ in 4 hours, then to 2000℃ in 4 hours, and held at 2000℃ for 5 hours to achieve carbonization treatment, thus obtaining the composite thermal insulation rigid felt.

[0080] Comparative Example 3 The difference between this comparative example and Example 1 lies in the different preparation methods of the composite thermal insulation felt. Specifically, the silicon-modified phenolic resin is replaced with an equal amount of phenolic resin prepared from the blank preparation example.

[0081] Performance testing Thermal insulation test: The finished products obtained in Examples 1-5 and Comparative Examples 1-3 were cut into test specimens. The thermal conductivity was tested at 1500℃ according to GB / T22588-2008 "Measuring thermal diffusivity or thermal conductivity by flash method". The results are shown in Table 1.

[0082] Thermal insulation durability test: The finished products obtained from Examples 1-5 and Comparative Examples 1-3 were placed in the same silicon carbide growth furnace for three months. During this period, the daily maximum operating temperature of the silicon carbide growth furnace reached 2400℃. After three months, the finished products were taken out and cut into test samples. Finally, the thermal conductivity was tested, and the results are shown in Table 1.

[0083] Structural stability: In the above heat insulation durability test, after three months, when the finished product is taken out and cut into test samples, observe whether there is any powder shedding during the cutting process, and press the finished product to observe whether it is brittle.

[0084] Table 1 As can be seen from the test results in Table 1, after three months of use, the composite thermal insulation felt of Examples 1-3 still maintains a low thermal conductivity, that is, it has good thermal insulation continuity, and has structural characteristics of no obvious powder shedding and not being easily broken. This indicates that the composite thermal insulation felt can resist the erosion of high-temperature steam in the environment when used under continuous high temperature in the silicon carbide thermal field, and has good durability.

[0085] The thermal conductivity of the finished product in Comparative Example 1 increased significantly after three months of use, its thermal insulation performance decreased, and its structural stability was poor. Compared with Example 1, this shows that the carbon-carbon composite sheet can play a barrier and protection role for the carbon fiber felt, thereby improving the overall structural stability of the composite thermal insulation felt, reducing the structural damage of the composite thermal insulation felt due to high-temperature steam erosion, and maintaining good thermal insulation performance.

[0086] The finished product of Comparative Example 2 also showed a decrease in thermal insulation and poor structural stability after three months of use. Compared with Example 1, this shows that the adhesive filled with graphite powder, carbon powder and silicon carbide powder between the carbon fiber felt and the carbon-carbon composite sheet can effectively enhance the bonding force between the carbon fiber felt and the carbon-carbon composite sheet, and has a certain high temperature resistance, further reducing the erosion of the internal structure by high temperature steam, thereby improving the thermal insulation and structural stability of the composite thermal insulation felt.

[0087] The finished product of Comparative Example 3 also showed a decrease in thermal insulation after three months of use and poor structural stability. Compared with Example 1, this shows that silicone-modified phenolic resin can improve the bonding ability and high temperature resistance of ordinary phenolic resin, thereby improving the thermal insulation and stability of composite thermal insulation felt.

[0088] The thermal insulation properties of the finished products in Examples 4 and 5 decreased slightly after three months of use, but the thermal conductivity remained below 0.40 W / km. This indicates that the addition of long-chain esters can improve the high-temperature resistance of the adhesive. In addition, the choice of the chain length of the long-chain esters also affects the thermal insulation properties.

[0089] In addition, the finished products obtained in Example 1 and Comparative Example 1 were used as insulation materials for two silicon carbide growth furnaces, respectively. The two silicon carbide growth furnaces maintained the same usage frequency and produced the same batch of products for three months. After three months of use, the energy consumption of the two silicon carbide growth furnaces was statistically analyzed. The final results showed that the silicon carbide growth furnace using the finished product of Example 1 as insulation material had 15.3% lower energy consumption than the silicon carbide growth furnace using the finished product of Comparative Example 1. This indicates that the finished product of Example 1 can resist the erosion of high-temperature gases in the thermal field, maintain the structural stability of the composite insulation felt, thereby maintaining its thermal insulation performance, reducing heat dissipation, and saving energy.

[0090] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A composite thermal insulation rigid felt, characterized in that: It includes a carbon fiber felt body and a carbon-carbon composite sheet, wherein the carbon-carbon composite sheet is attached to the surface of the carbon fiber felt body by an adhesive, the adhesive being made of components comprising the following weight percentages: Furan resin 20-25%; Silicon-modified phenolic resin 5-8%; Graphite powder 5-8%; 15-20% toner; 1-2% silicon carbide powder; Dispersant 2-3%; Carbonization aid 1~2%; The remainder is solvent; The silicon-modified phenolic resin is a long-chain silane coupling agent modified phenolic resin. The long-chain silane coupling agent is formed by reacting a long-chain ester with an aminosilane coupling agent. The long-chain silane coupling agent is added during the synthesis of phenolic resin to obtain the long-chain silane coupling agent modified phenolic resin. The long-chain ester is selected from one or both of butyl dodecanoate and butyl tetradecanoate.

2. The composite thermal insulation rigid felt according to claim 1, characterized in that: The carbon-carbon composite sheet is made of carbon fiber cured with resin, with a carbon fiber to resin mass ratio of 1:(1.5~1.7), a thickness of 3±1mm, and a density of 1.5~1.8g / cm³. 3 .

3. The composite thermal insulation rigid felt according to claim 1, characterized in that: The dispersant is selected from one or more of diethylene glycol butyl ether, propylene glycol methyl ether, and triethylene glycol monobutyl ether.

4. The composite thermal insulation rigid felt according to claim 1, characterized in that: The carbonization aid is selected from cellulose and / or cellulose derivatives.

5. The composite thermal insulation rigid felt according to claim 1, characterized in that: The carbon fiber felt is made by coating carbon fiber soft felt with silicon-modified phenolic resin, and the mass ratio of the carbon fiber soft felt to the silicon-modified phenolic resin is 1:(1~1.5).

6. A method for preparing a composite thermal insulation rigid felt according to any one of claims 1-5, characterized in that: Includes the following steps: The solvent, furan resin and silicon-modified phenolic resin are mixed and stirred, then carbon powder, graphite powder and silicon carbide are added and mixed and stirred, and then dispersant and carbonization aid are added and mixed and stirred to obtain the binder. An adhesive is applied to the surface of the carbon-carbon composite sheet, and the carbon fiber soft felt is attached to the carbon-carbon composite sheet and baked to obtain a preliminary composite hard felt. The preliminary composite rigid felt is placed in an environment of not less than 2000℃ for vacuum high-temperature carbonization treatment to obtain composite thermal insulation rigid felt.

7. The method for preparing a composite thermal insulation rigid felt according to claim 6, characterized in that: The preparation method of the silicon-modified phenolic resin includes the following steps: Under the protection of an inert gas, an aminosilane coupling agent, a long-chain ester, and an organic solvent are mixed and heated to 80-90°C to react. After the reaction is completed, the solvent is removed by negative pressure distillation to obtain the long-chain silane coupling agent. The long-chain silane coupling agent and ethanol solution were mixed, the pH was adjusted to weakly alkaline, and hydrolysis was performed to obtain a hydrolyzed mixture. Phenol and a portion of the catalyst solution are mixed and heated to 60-70℃ for 20-40 minutes. Then, a portion of formaldehyde is added and heated to 85-90℃ for 1-1.5 hours. The remaining catalyst solution and formaldehyde are then added, and the hydrolysis mixture is added dropwise to the reaction solution. The reaction continues for 1-2 hours. The pH is then adjusted to neutral, and the mixture is dehydrated under vacuum to obtain silicon-modified phenolic resin.

8. The method for preparing a composite thermal insulation rigid felt according to claim 6, characterized in that: The method for preparing the carbon-carbon composite sheet includes the following steps: Short carbon fibers are formed by airflow and then needle-punched to form a carbon fiber mesh. The carbon fiber mesh is then placed in a mold, resin is added to the mold, the mold is pressed together, and it is pre-cured at 170~180℃ for 2~3 hours. After demolding, it is placed in a vacuum furnace at 2000~2100℃ for 4~5 hours to finally obtain a carbon-carbon composite sheet.

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