High heat flux resistant flexible thermal insulation material and method of making same

Abstract

The application relates to a high-heat-flow-resistant flexible heat insulation material and a preparation method thereof, and relates to the field of heat insulation materials. The application adopts a coating combined with a calendering method to prepare an organic silicon compound of a mixed special functional additive on the surface of a high-temperature-resistant fiber cloth to form a hot surface layer flexible composite material. The hot surface layer material has large deformation capacity and high bearing capacity, can take away part of heat through ablation under high heat flow / high temperature, reduces the heat entering the material interior, improves the heat insulation effect, and has good waterproof performance. The special functional additive has high temperature resistance and low thermal conductivity, and can form a pinning effect to produce a thermal blocking effect on external heating. The inner layer is designed as a multi-layer flexible heat insulation material with high temperature resistance and different components, and the heat insulation effect can be further improved. Several layers are combined to obtain the high-heat-flow-resistant flexible heat insulation material through integrated forming.

Description

Technical Field

[0001] This invention relates to a high heat flux resistant flexible thermal insulation material and its preparation, belonging to the field of thermal protection materials. Background Technology

[0002] Spacecraft have become a hot research and development area for countries around the world. High flight speeds result in intense friction with the surrounding air, generating heat that causes a rapid increase in surface temperature. To ensure the safe operation of spacecraft, thermal protection of their surfaces is essential. Flexible thermal insulation materials can be made into large shapes, do not suffer from thermal stress, and are easier to install, offering unparalleled advantages for thermal insulation of large areas and complex shapes.

[0003] Ceramic fiber flexible thermal insulation materials were first used in the thermal protection system (TPS) of near-space vehicles. The surface temperature of a spacecraft varies in different heat flux density zones. Flexible thermal insulation materials are mainly used for thermal insulation in lower temperature zones (such as the leeward side and hatches). An early application of flexible thermal insulation materials was on the leeward side of the US Space Shuttle. Typical examples include FRSI (Flexible Resulable Surface Insulation), mainly composed of quartz fiber cloth, felt, and yarn, with a maximum operating temperature generally not exceeding 815℃; AFRSI (Advanced Flexible Resulable Surface Insulation) uses aluminosilicate fiber cloth and yarn, with an operating temperature reaching 1037℃ and a room temperature thermal conductivity of approximately 0.033 W / (m·K); and CFBI (Composite Flexible Blanket Insulation) uses SiC fiber yarn and fabric, and employs a multi-layer structure composed of an aluminized polyimide reflective film, with a room temperature thermal conductivity of ~0.035 W / (m·K). The CRI (Conformal Resulable Insulation) was developed by Boeing and has a maximum operating temperature of 1200°C. Its high-temperature and low-temperature surfaces use Nextel 440 aluminosilicate fiber cloth and quartz fiber cloth, respectively. The middle layer is mainly composed of ceramic fibers such as alumina, silicon oxide, and boron oxide, and is made using a sewing process.

[0004] Domestic researchers, including Zhang Hongbo, have developed a flexible thermal insulation material. This material is constructed by sequentially layering glass fiber cotton and fiber cloth, then stitching glass fiber sutures through each layer to create a quilt-like structure. It achieves a long-term operating temperature of 600℃ and a short-term operating temperature of 800–1000℃, with performance comparable to similar foreign materials. Li Zhenyu used organosilicon as the matrix material and fumed SiO2 as the matrix reinforcement material, adding hydrophobic SiO2 aerogel thermal insulation filler. He also prepared a ZnO / organosilicon reflective layer and a glass fiber cloth / organosilicon structural layer, forming a novel flexible multilayer thermal insulation structure. This new flexible multilayer thermal insulation structure effectively improves the total thermal resistance of the insulation material, exhibiting good thermal insulation performance with a thermal conductivity of 0.257 W / (m·K) at 250℃. Xue Yunjia et al. sequentially laid out silicon-aluminum ceramic fiber cloth and flexible quartz cotton core, then mechanically sewed them together using silicon-aluminum ceramic fiber thread. The stitches were lockstitches with a stitch spacing of 10 mm, and then the edges were overlocked with ceramic fiber thread to obtain a test sample with dimensions of 100 mm × 80 mm × 15 mm. Wu Wenjun et al. introduced nanoporous structures and multi-layer reflective screens into flexible thermal insulation felt, designing a flexible nano-thermal insulation material with a multi-layer reflective structure. Feng Junzong et al. used tetraethyl orthosilicate (TEOS) as raw material, prepared a sol using an acid-base catalytic two-step method, impregnated flexible fiber felt, and then prepared a flexible thermal insulation composite material through supercritical drying. Sun Xiankai et al. prepared a stitched layered flexible thermal insulation material using alumina fiber paper and graphite paper. Sun Shichao et al. prepared a flexible thermal insulation material with an operating temperature exceeding 1000℃ using alumina fiber and graphite foil. Guo Jianye et al. wrapped fiber cloth around fiber felt and sewed it together to form a fiber preform; they then coated the fiber cloth at the edge of the fiber preform with silicone rubber to prepare a cuttable, high-temperature resistant, flexible heat-insulating and sealing material. Chen Zhaofeng et al. laminated sepiolite felt and fiberglass felt to prepare a lightweight sepiolite / fiberglass sound and heat insulation felt.

[0005] Based on the above examples, the maximum operating temperature of ceramic fiber flexible thermal insulation materials is mostly no more than 1200℃. The main components are ceramic fiber cloth, yarn, cotton, felt, thread, fabric and a small amount of reflective material. The thermal surface layer is almost entirely made of ceramic fiber products, which can hardly resist the erosion of high heat flow and waterproofing. Some of them also have oxidation problems. Summary of the Invention

[0006] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a high heat flux resistant flexible thermal insulation material and its preparation method. It has high operating temperature, high heat flux resistance, no special requirements for the use environment, simple manufacturing process, simple and easy operation, and certain waterproof properties. It can also improve the reliability of long-term storage.

[0007] The technical solution provided in this application is as follows:

[0008] A high heat flux resistant flexible thermal insulation material includes a thermal surface layer flexible composite material and an inner thermal insulation material. The inner thermal insulation material has a bottom surface, a top surface, and multiple connecting surfaces connected to the edges of the bottom and top surfaces. The thermal surface layer flexible composite material covers the other surfaces of the inner thermal insulation material except for the bottom surface. The thermal surface layer flexible composite material includes a high-temperature resistant fiber cloth and a mixed slurry attached to the surface of the high-temperature resistant fiber cloth. The mixed slurry includes special functional additives and silicone rubber. The special functional additives are selected from gaseous nano-SiO2, gaseous Al2O3 powder, micron-sized SiC or ZrO2 powder.

[0009] The thickness of the flexible composite material of the thermal surface layer is 1-6 mm, and the thickness of the inner thermal insulation material is not less than 2 mm.

[0010] The high-temperature resistant fiber cloth has a single-sided margin of 5-40mm at the edge where the mixed slurry is attached; based on the total mass of the mixed slurry and the high-temperature resistant fiber cloth attached to the mixed slurry being 100%, the mass content of the high-temperature resistant fiber cloth attached to the mixed slurry is 15.25-63.74wt%, and the mass content of the mixed slurry is 36.26-84.75wt%.

[0011] The mass content of special functional additives in the mixed slurry is 0.08 to 8.5 wt%.

[0012] The high-temperature resistant fiber cloth is selected from fiber cloth containing alumina or silicon carbide fiber cloth.

[0013] The high-temperature resistant fiber cloth has a mixed slurry of equal thickness applied to both sides. The double-sided equal-thickness toughening treatment of the high-temperature resistant fiber cloth includes:

[0014] Design a double-layer positioning mold;

[0015] The double-layer positioning mold includes a first layer mold and a second layer mold arranged sequentially from the bottom. The upper surface of the first layer mold is provided with a groove, and the second layer mold is provided with a through hole facing the groove.

[0016] A mixed slurry is placed in the groove of the first mold, and then a high-temperature resistant fiber cloth is laid on the surface of the first mold. The second mold is then placed on the high-temperature resistant fiber cloth, with the edge of the high-temperature resistant fiber cloth located outside the first and second molds to protect the edge. The second mold is provided with a through hole facing the position where the mixed slurry is attached to the high-temperature resistant fiber cloth. The mixed slurry is poured into the upper surface of the high-temperature resistant fiber cloth through the through hole. After calendering and curing, a flexible composite material with a hot surface layer is obtained.

[0017] The inner insulation material includes ceramic fiber cloth, ceramic fiber cotton / felt / paper and continuous ceramic fiber yarn, which is used to sew together multiple layers of ceramic fiber cloth and multiple layers of ceramic fiber cotton / felt / paper.

[0018] In the inner insulation material, based on the mass percentage of each component as 100%, the content of ceramic fiber cloth is 17-62 wt%, the content of ceramic fiber cotton / felt / paper is 62.5-82 wt%, and the content of continuous ceramic fiber yarn is 1.7-5 wt%.

[0019] The ceramic fiber cloth is selected from fiber cloth containing alumina, silicon carbide fiber cloth or quartz fiber cloth; the ceramic fiber cloth must contain fiber cloth containing alumina or silicon carbide fiber cloth.

[0020] The alumina-containing fiber fabric is selected from Nextel 550 fiber containing about 73 wt% alumina, Nextel 610 fiber containing >99 wt% alumina, or Nextel 720 fiber containing about 85 wt% alumina.

[0021] The ceramic fiber cotton / felt / paper is selected from mullite fiber cotton / felt, zirconia fiber paper or quartz fiber cotton / felt; the ceramic fiber cotton / felt / paper must contain mullite fiber cotton / felt or zirconia fiber paper.

[0022] The continuous ceramic fiber yarn is selected from continuous alumina fiber yarn, continuous silicon carbide fiber yarn, or quartz fiber yarn.

[0023] The inner insulation material is laid in the following order from the hot surface layer to the cold surface layer: ceramic fiber cloth, ceramic fiber cotton / felt / paper and ceramic fiber cloth. The ceramic fiber cloth near the hot surface layer is made of fiber cloth containing alumina or silicon carbide fiber cloth, and the ceramic fiber cloth near the cold surface layer is made of fiber cloth containing alumina, silicon carbide fiber cloth or quartz fiber cloth.

[0024] A method for preparing a high heat flux resistant flexible thermal insulation material includes:

[0025] Step 1: Cut and weigh the required raw materials;

[0026] Based on density and composition requirements, calculate the mass of each component, and cut and weigh them to obtain the raw materials. The cutting dimensions of the ceramic fiber cotton / felt / paper are determined according to the finished product dimensions; the dimensions of the high-temperature resistant fiber cloth require allowance for edge binding, with a single-sided allowance of 4–50 mm.

[0027] Step 2: Preparation of flexible composite material for the thermal surface layer

[0028] Special functional additives are first introduced into silicone rubber to form a mixed slurry. According to the preset thickness, a corresponding double-layer positioning mold is selected. Through filling, scraping, and calendering, the high-temperature resistant ceramic fiber cloth is subjected to double-sided equal-thickness toughening treatment. After curing, a flexible composite material with a hot surface layer is obtained.

[0029] The third step: layering treatment;

[0030] The layering sequence from the hot surface to the cold surface is as follows: ceramic fiber cloth (one of Nextel 550, Nextel 610, Nextel 720, and silicon carbide fiber cloth), ceramic fiber cotton / felt / paper, ceramic fiber cloth (one of Nextel 550, Nextel 610, Nextel 720, silicon carbide fiber cloth, and quartz fiber cloth), to obtain multi-layer raw materials.

[0031] The fourth step: stitching;

[0032] Use ceramic fiber yarn to pass through the multi-layer raw materials obtained in the third step and stitch them in a "plate" shape to stitch the multi-layer raw materials into a whole, obtaining the inner thermal insulation material. The overall strength of the material can be achieved by designing different sewing densities of fiber yarns and adjusting the number of strands of a single bundle of fiber yarns.

[0033] The fifth step: integration treatment;

[0034] Perform a surrounding stitching and wrapping treatment on the hot surface layer flexible composite material obtained in the second step and the inner thermal insulation material obtained in the fourth step to produce any one of the above-mentioned high heat flux resistant flexible thermal insulation materials.

[0035] During the preparation process of the hot surface layer flexible composite material, after the high temperature resistant fiber cloth is toughened on both sides, the upper surface is covered and pressed with a flat metal plate, and the metal plate pressure ≥ 125 Pa; cure at room temperature, and the curing time is 4 - 10 days. When the weight change within 24 hours < 0.1%, it can be demolded for use.

[0036] The "plate" shape stitching mentioned in the stitching step is achieved through the following steps: the one-way stitch is sewn in a continuous "zigzag" shape, sewn from the upper and lower surfaces respectively, and the two surfaces are combined to form a "plate" shape.

[0037] This application uses a method of coating combined with calendering to prepare an organosilicon compound with a mixed special functional additive on the surface of a high temperature resistant fiber cloth to form a hot surface layer flexible composite material. This hot surface layer material has a large deformation ability and a high bearing capacity, and can also带走部分热量,减少进入材料内部的热量,提高隔热效果,并具有良好的防水性能;特种功能添加物耐高温、低热导率,还可形成钉扎作用,对外部加热产生热阻塞的效应;内层设计成耐高温、不同组分的多层柔性隔热材料,可进一步提高隔热效果;将几层组合起来,通过一体化成型,得到耐高热流柔性隔热材料。

[0038] In this patent, the heating surface layer is designed as a flexible composite material with uniform, controllable, adjustable thickness and high flexibility. Utilizing the thermal decomposition characteristics of polymer composite materials, the generated pyrolysis gas flows to the heated surface through the pores within the heat-insulating structure. During the pyrolysis process and as the pyrolysis gas flows to the high-temperature area of ​​the heated surface layer, it absorbs external heating and creates a thermal blockage effect. The internal design incorporates a multi-layered heat insulation structure to further enhance the insulation effect. This material has high operating temperatures, withstands high heat flux, has no special environmental requirements, is simple to manufacture, easy to use, and possesses a certain degree of water resistance, thus improving the reliability of long-term storage.

[0039] In summary, this application includes at least the following beneficial technical effects:

[0040] (1) Multi-layer structure design and material selection

[0041] The material employs a multi-layer structure, primarily consisting of a heating surface layer and an insulating inner layer. The heating surface layer is designed as a flexible composite material, using high-temperature resistant fiber cloth (such as alumina fiber and silicon carbide fiber cloth) as the skeleton material, special functional additives as fillers, and composited with silicone rubber to form the flexible composite material. This layer utilizes the thermal decomposition properties of silicone rubber, generating pyrolysis gases that flow through the pores of the fiber cloth structure to the heated surface. During the pyrolysis process and as the pyrolysis gases flow to the high-temperature areas of the heated surface, they absorb external heat and create a thermal blocking effect. The high-temperature resistant, low-thermal-conductivity, and low-density special functional additive fillers not only act as a pinning agent, forming thermal blockage, but also reduce the density of the heating surface composite material. This heating surface composite material exhibits a large deformation range, high load-bearing capacity, good fatigue performance, and waterproof properties. Another notable characteristic of this material is that it exhibits low stiffness under low stress, but possesses considerable strength and stiffness under high stress. The inner layer is designed as a multi-layered flexible thermal insulation material, which is resistant to high temperatures, has low density, and a loose structure, resulting in low thermal conductivity. Its thermal insulation performance is superior to that of relatively dense hot-surface flexible thermal insulation composite materials. When used as an inner layer, it can improve the thermal insulation effect.

[0042] (2) A method for realizing flexible composite materials with high flexibility, controllable thickness and adjustable hot surface layer.

[0043] Special functional additives are first introduced into silicone rubber to form a mixed slurry, which toughens the high-temperature resistant fiber cloth skeleton. Through filling, coating, and calendering methods, using a two-layer positioning with a fixed-height mold, double-sided toughening of silicone rubber, and integrated pressure molding, a flexible hot-surface composite material with high flexibility, uniform and controllable thickness is prepared.

[0044] (3) Multi-layer composite integrated molding method.

[0045] The inner layer is a multi-layer flexible heat insulation material layer, which is composed of loose fiber cotton. The dimensional stability of the material is poor. Without other treatments, it is prone to displacement and shedding during use, resulting in unstable performance. The design adopts combined sewing / locating of the inner layer to form a "dish" - shaped stitching, which plays a role in positioning and stabilizing the size, and then stitches with the bottom surface around the heat - resistant layer to form an integrated structure.

[0046] (4) The flexible heat insulation material of this application has a service temperature ≥ 1450 °C (passed the 1MW / m , , , , , , , 3 , , , ,

[0051] , ,

[0050] ,

[0056] , 2 ,

[0049] ,

[0055] ,

[0048] ,

[0054] ,

[0047] ,

[0053] ,

[0052] heat flux test), room - temperature thermal conductivity < 0.045W / (m·K), density < 0.46g / cm 3 . After the material passes the 1MW / m 2 heat flux test, the material remains intact and meets the requirements of heat insulation and protection. The preparation method of this material is simple and easy to implement, and at the same time has the advantages of controllable and adjustable quality, short preparation cycle, convenient installation, and waterproof, etc. It is one of the important directions for the development of thermal protection. Specific embodiments

[0047] The following embodiments are used to further illustrate this embodiment.

[0048] The inner - layer heat - insulation material has a bottom surface, a top surface, and a plurality of connecting surfaces connecting the edges of the bottom surface and the top surface. Among them, the shapes and sizes of the bottom surface and the top surface are the same and face each other. The shapes of the bottom surface and the top surface can be various shapes such as rectangle, square, triangle, etc. The bottom surface is used to connect to the surface of the aircraft. The following embodiments take the inner - layer heat - insulation layer with a square - shaped bottom surface as a quadrangular prism shape as an example, and the heat - resistant layer flexible composite material covers other surfaces of the inner - layer heat - insulation material except the bottom surface.

[0049] The high - heat - flux - resistant flexible heat - insulation material described in this invention mainly consists of a high - heat - flux - resistant heat - resistant layer and an insulating inner layer. The specific preparation steps are as follows:

[0050] (1) Cut and weigh fiber cloth, fiber paper, etc. according to the size, and weigh fiber cotton felt, functional additive powder, fiber yarn, and silicone rubber, etc. according to the proportion;

[0051] (2) Mix the functional additive powder and silicone rubber evenly to form a slurry;

[0052] (3) Double - side toughen the heat - resistant layer fiber cloth with the designed size, and obtain the heat - resistant layer flexible composite material after curing;

[0053] (4) Synchronously carry out the sewing of the internal heat - insulation material layer;

[0054] (5) Integrally sew the heat - resistant layer flexible composite material and the internal heat - insulation material layer.

[0055] Example 1:

[0056] A high heat flux resistant flexible thermal insulation material includes a thermal surface layer flexible composite material and an inner thermal insulation material. The thermal surface layer flexible composite material has a thickness of 1.83 mm and a mass of 143.02 g, and the inner thermal insulation material has a thickness of 20 mm and a mass of 162.0 g.

[0057] The flexible composite material for the hot surface layer includes 32.4g of silicon carbide fiber cloth with a size of 300mm×300mm, special functional additives (including 2.5g of fumed alumina powder and 0.3g of micron-sized silicon carbide powder) and 88.2g of silicone rubber.

[0058] The preparation steps of the hot-surface flexible composite material include: introducing fumed alumina and micron-sized silicon carbide powder into silicone rubber to form a mixed slurry; then, double-sided toughening of a 300mm×300mm silicon carbide fiber cloth by filling and coating (double-sided toughening is performed on a 250mm×250mm area in the middle of the silicon carbide fiber cloth, with a 50mm margin, i.e., 25mm on each side; the mass of the 250mm×250mm area in the middle of the silicon carbide fiber cloth is 134.02g based on the area). The total thickness of the double-layer positioning mold is 1.8mm (the thickness of the silicon carbide fiber cloth is 0.43mm). A 2kg 300mm×300mm stainless steel plate is used for pressing, followed by room temperature curing for 6 days. After curing, a hot-surface flexible composite material with a thickness of 1.83mm and a mass of 143.02g is obtained.

[0059] The inner insulation material includes 22.5g of silicon carbide fiber cloth in size 250mm×250mm, 126.2g of mullite asbestos felt in size 200mm×200mm, 8.1g of quartz cloth in size 200mm×200mm, and 4.8g of silicon carbide continuous fiber yarn.

[0060] The preparation steps of the inner insulation material include: laying silicon carbide fiber cloth, mullite fiber cotton felt and quartz fiber cloth in sequence from the hot surface layer to the cold surface layer, and sewing them together to obtain an inner insulation material with a thickness of 20 mm and a weight of 162.0 g.

[0061] Finally, the flexible composite material of the hot surface layer and the inner thermal insulation material layer (silicon carbide fiber cloth layer close to the hot surface layer) are integrated and sewn together with 4.8g of continuous silicon carbide fiber yarn to obtain a flexible thermal insulation material with high heat flux resistance.

[0062] The material density at this point is 0.36 g / cm³. 3 The room temperature thermal conductivity is 0.045 W / (m·K), and the hydrophobic angle of the hot surface layer is 103°.

[0063] Example 2:

[0064] A high heat flux resistant flexible thermal insulation material includes a thermal surface layer flexible composite material and an inner thermal insulation material. The thermal surface layer flexible composite material has a thickness of 1.82 mm and a weight of 126.1 g, and the inner thermal insulation material has a thickness of 20 mm and a weight of 197.7 g.

[0065] The flexible composite material for the hot surface layer includes 33.3g of Nextel 720 alumina fiber cloth with a size of 300mm×300mm, special functional additives (including 1.5g of fumed alumina powder, 1.0g of fumed silica powder, 0.1g of micron-sized silicon carbide powder, and 0.2g of micron-sized zirconium oxide powder) and 90g of silicone rubber.

[0066] The preparation steps of the hot-surface flexible composite material include: introducing fumed alumina and silica, micronized zirconium oxide and silicon carbide powders into silicone rubber to form a mixed slurry; then, double-sided toughening of a 300mm×300mm Nextel 720 alumina fiber cloth by filling and coating (double-sided toughening is performed on a 250mm×250mm area in the middle of the Nextel 720 alumina fiber cloth, with a 50mm margin, i.e., 25mm on each side; based on area, the mass of the 250mm×250mm area in the middle of the Nextel 720 alumina fiber cloth is 116.85g). The total thickness of the double-layer positioning mold is 1.8mm (the thickness of the Nextel 720 alumina fiber cloth is 0.29mm); a 2kg 300mm×300mm stainless steel plate is used for pressing; and then it is cured at room temperature for 6 days. After curing, a hot-surface flexible composite material with a thickness of 1.82mm and a mass of 126.1g is obtained.

[0067] The inner insulation material includes 23.1g of Nextel 720 alumina fiber cloth with a size of ~250mm×250mm, 162g of zirconium oxide fiber paper with a size of ~200mm×200mm, 4.7g of Nextel 720 alumina continuous yarn, 4.5g of quartz fiber continuous yarn, and 8.1g of quartz fiber cloth.

[0068] The preparation steps of the inner insulation material include: laying Nextel 720 alumina fiber cloth, zirconium oxide fiber paper and quartz fiber cloth in sequence from the hot surface layer to the cold surface layer, and sewing them together with continuous quartz fiber yarn to obtain an inner insulation material with a thickness of 20 mm and a weight of 197.7 g.

[0069] Finally, the flexible composite material of the hot surface layer and the inner thermal insulation material layer (Nextel 720 alumina fiber cloth layer near the hot surface layer) are stitched together with 4.7g Nextel 720 alumina continuous yarn to obtain a flexible thermal insulation material with high heat flux resistance.

[0070] The material density at this point is 0.46 g / cm³. 3 The thermal conductivity at room temperature is 0.040 W / (m·K), and the hydrophobic angle of the hot-surface layer is 103°. The material undergoes a 1MW / m... 2 After a 20-second test, the thermal surface fiber cloth remained intact, with a back temperature of 32℃; after 1MW / m 2 After a 150s test, the heat-resistant fiber cloth remained intact, with a back temperature of 45℃.

[0071] Example 3:

[0072] A high heat flux resistant flexible thermal insulation material includes a thermal surface layer flexible composite material and an inner thermal insulation material. The thermal surface layer flexible composite material has a thickness of 1.79 mm and a weight of 129.05 g, and the inner thermal insulation material has a thickness of 19.5 mm and a weight of 137.8 g.

[0073] The flexible composite material for the hot surface layer includes 33.3g of Nextel 610 alumina fiber cloth with a size of ~300mm×300mm, special functional additives (including 2.0g of fumed alumina powder, 0.5g of fumed silica powder, and 0.25g of micron-sized silicon carbide powder) and 93g of silicone rubber.

[0074] The preparation steps of the hot-surface flexible composite material include: introducing fumed alumina powder, fumed silica powder, and micron-sized silicon carbide powder into silicone rubber to form a mixed slurry; then, double-sided toughening of a 300mm×300mm Nextel 610 alumina fiber cloth by filling and coating (double-sided toughening of the middle 250mm×250mm area of ​​the Nextel 610 alumina fiber cloth, with a 50mm margin, i.e., 25mm on each side; based on area, the mass of the middle 250mm×250mm area of ​​the Nextel 610 alumina fiber cloth is 107.6g). The total thickness of the double-layer positioning mold is 1.8mm (the thickness of the Nextel 610 alumina fiber cloth is 0.29mm); a 2kg 300mm×300mm stainless steel plate is used for pressing; and then it is cured at room temperature for 6 days. After curing, a hot-surface flexible composite material with a thickness of 1.79mm and a mass of 129.05g is obtained.

[0075] The inner insulation material includes 23.1g of Nextel 610 alumina fiber cloth with a size of ~250mm×250mm, 72g of zirconium oxide fiber paper with a size of ~200mm×200mm, 20g of quartz fiber cotton felt with a size of ~200mm×200mm, 4.7g of quartz fiber continuous yarn, and 18g of quartz fiber cloth with a size of ~300mm×300mm.

[0076] The preparation steps of the inner insulation material include: laying Nextel 610 alumina fiber cloth, zirconium oxide fiber paper, quartz fiber cotton felt and quartz fiber cloth in sequence from the hot surface layer to the cold surface layer, and sewing them together to obtain an inner insulation material with a thickness of 19.5 mm and a weight of 137.8 g.

[0077] Finally, the flexible composite material of the hot surface layer and the inner thermal insulation material layer (Nextel 610 alumina fiber cloth layer near the hot surface layer) are integrated and sewn together with 3.7g Nextel 610 alumina fiber continuous yarn to obtain a flexible thermal insulation material with high heat flux resistance.

[0078] The material density at this point is 0.35 g / cm³. 3 The thermal conductivity at room temperature is 0.043 W / (m·K), and the hydrophobic angle of the hot-surface layer is 105°. The material undergoes a 1MW / m... 2 After a 20-second test, the thermal surface fiber cloth remained intact, with a back temperature of 32℃; after 1MW / m 2 After a 40-second test, the heat-resistant fiber cloth remained intact, with a back temperature of 47°C.

[0079] Example 4:

[0080] A high heat flux resistant flexible thermal insulation material includes a thermal surface layer flexible composite material and an inner thermal insulation material. The thermal surface layer flexible composite material has a thickness of 1.01 mm and a weight of 70.9 g, and the inner thermal insulation material has a thickness of 19.5 mm and a weight of 243.3 g.

[0081] The flexible composite material for the hot surface layer includes 33.3g of Nextel 720 alumina fiber cloth with a size of ~300mm×300mm, special functional additives (including 1.5g of fumed alumina powder, 1.0g of fumed silica powder, 0.1g of micron-sized silicon carbide powder, and 0.2g of micron-sized zirconium oxide powder) and 34.8g of silicone rubber.

[0082] The preparation steps of the hot-surface flexible composite material include: introducing fumed alumina, fumed silica, micron-sized silicon carbide, and micron-sized zirconium oxide powders into silicone rubber to form a mixed slurry; then, double-sided toughening of a 300mm×300mm Nextel 720 alumina fiber cloth by filling and coating (double-sided toughening of the middle 250mm×250mm area of ​​the Nextel 720 alumina fiber cloth, with a 50mm margin, i.e., 25mm on each side; based on area, the mass of the middle 250mm×250mm area of ​​the Nextel 720 alumina fiber cloth is 60.65g). The total thickness of the double-layer positioning mold is 0.8mm (the thickness of the Nextel 720 alumina fiber cloth is 0.29mm); a 2kg 300mm×300mm stainless steel plate is used for pressing; and then it is cured at room temperature for 5 days. After curing, a hot-surface flexible composite material with a thickness of 1.01mm and a mass of 70.9g is obtained.

[0083] The inner insulation material includes 23.1g of Nextel 720 alumina fiber cloth with a size of ~250mm×250mm, 162g of zirconium oxide fiber paper with a size of ~200mm×200mm, 36g of quartz fiber cotton felt with a size of ~200mm×200mm, 4.2g of quartz fiber continuous yarn, and 18.0g of quartz fiber cloth with a size of ~300mm×300mm.

[0084] The preparation steps of the inner insulation material include: laying Nextel 720 alumina fiber cloth, zirconium oxide fiber paper, quartz fiber cotton felt and quartz fiber cloth in sequence from the hot surface layer to the cold surface layer, and sewing them together to obtain an inner insulation material with a thickness of 19.5 mm and a weight of 243.3 g.

[0085] Finally, the flexible composite material of the hot surface layer and the inner thermal insulation material layer (Nextel 720 alumina fiber cloth near the hot surface layer) are stitched together with 4.7g Nextel 720 alumina fiber continuous yarn to obtain a flexible thermal insulation material with high heat flux resistance.

[0086] The material density at this point is 0.41 g / cm³. 3 The thermal conductivity at room temperature is 0.039 W / (m·K), and the hydrophobic angle of the hot surface layer is 91°. The material undergoes a 1MW / m... 2 After a 20-second test, the thermal surface fiber cloth remained intact, with a back temperature of 28℃; after 1MW / m 2 After a 150s test, the heat-resistant fiber cloth remained intact, with a back temperature of 55℃.

[0087] Example 5:

[0088] A high heat flux resistant flexible thermal insulation material includes a thermal surface layer flexible composite material and an inner thermal insulation material. The thermal surface layer flexible composite material has a thickness of 1.19 mm and a weight of 68.95 g, and the inner thermal insulation material has a thickness of 15.80 mm and a weight of 122.10 g.

[0089] The flexible composite material for the hot surface layer includes 25.2g of Nextel 550 alumina fiber cloth with a size of ~300mm×300mm, special functional additives (including 0.2g of fumed silica powder and 0.05g of micron-sized silicon carbide powder) and 43.5g of silicone rubber.

[0090] The preparation steps of the hot-surface flexible composite material include: introducing fumed silica powder and micron-sized silicon carbide powder into silicone rubber to form a mixed slurry; then, double-sided toughening of a 300mm×300mm Nextel 550 alumina fiber cloth by filling and coating (double-sided toughening is performed on a 250mm×250mm area in the middle of the Nextel 550 alumina fiber cloth, with a 50mm margin, i.e., 25mm on each side; based on area, the mass of the 250mm×250mm area in the middle of the Nextel 550 alumina fiber cloth is 61.95g). The total thickness of the double-layer positioning mold is 1.0mm (the thickness of the Nextel 550 alumina fiber cloth is 0.27mm); a 2kg 300mm×300mm stainless steel plate is used for pressing; and then it is cured at room temperature for 5 days. After curing, a hot-surface flexible composite material with a thickness of 1.19mm and a mass of 68.95g is obtained.

[0091] The inner insulation material includes 17.5g of Nextel 550 alumina fiber cloth with a size of ~250mm×250mm, 11.2g of Nextel 550 alumina fiber cloth with a size of ~200mm×200mm, 90g of zirconium oxide fiber paper with a size of ~200mm×200mm, and 3.4g of Nextel 550 alumina fiber continuous yarn.

[0092] The preparation steps of the inner insulation material include: laying Nextel 550 alumina fiber cloth, zirconium oxide fiber paper and Nextel 550 alumina fiber cloth in sequence from the hot surface layer to the cold surface layer, and sewing them together to obtain an inner insulation material with a thickness of 15.80 mm and a weight of 122.10 g.

[0093] Finally, the flexible composite material of the hot surface layer and the inner thermal insulation material layer (Nextel 550 alumina fiber cloth near the hot surface layer) are stitched together with 3.4g Nextel 550 alumina fiber continuous yarn to obtain a flexible thermal insulation material with high heat flux resistance.

[0094] The material density at this point is 0.31 g / cm³. 3 The room temperature thermal conductivity is 0.042 W / (m·K), and the hydrophobic angle of the hot surface is 93°.

[0095] Example 6

[0096] The only difference from Example 2 is that the types of special functional additives remain the same, and the proportions of each additive are the same. The total amount of special functional additives changes from 2.8g in Example 2 to 4.6g. The total amount of special functional additives and silicone rubber is the same, and the mass of silicone rubber changes to 88.2g.

[0097] The material density at this point is 0.46 g / cm³. 3 The thermal conductivity at room temperature is 0.040 W / (m·K), and the hydrophobic angle of the hot-surface layer is 58°. The material undergoes a 1MW / m... 2 After a 20-second test, the thermal surface fiber cloth remained intact, with a back temperature of 33℃; after 1MW / m 2 After a 150s test, the heat-resistant fiber cloth remained intact, with a back temperature of 42℃.

[0098] Example 7

[0099] The only difference from Example 2 is that the types of special functional additives remain the same, and the proportions of each additive are the same. The total amount of special functional additives changes from 2.8g in Example 2 to 1.01g. The total amount of special functional additives and silicone rubber is the same, and the mass of silicone rubber changes to 91.79g.

[0100] The material density at this point is 0.46 g / cm³. 3 The thermal conductivity at room temperature is 0.040 W / (m·K), and the hydrophobic angle of the hot surface layer is 112°. The material undergoes a 1MW / m... 2 After a 20-second test, the thermal surface fiber cloth remained intact, with a back temperature of 31℃; after 1MW / m 2 After 150 seconds of testing, the hot surface fiber cloth was damaged, and the sample was damaged with no back temperature data.

[0101] Examples 1-5 illustrate that in the technical solution of the thermal insulation material defined in this application, the flexible thermal insulation material has an operating temperature ≥1450℃ (all passed 1MW / m). 2 Thermal flux test), room temperature thermal conductivity <0.045 W / (m·K), density <0.46 g / cm³ 3 The material was processed at 1MW / m 2 After the heat flow test, the material remained intact and met the heat insulation requirements.

[0102] In Examples 2, 6, and 7, the only difference is the ratio of special functional additives to silicone rubber. It can be seen that within the range of special functional additives and silicone rubber content defined in this application, when the flexible composite material of the hot-surface layer is heated, the silicone rubber decomposes to produce pyrolysis gas. The flow of pyrolysis gas carries away some heat and forms thermal blockage. Simultaneously, the ceramic particles with a certain density distribution formed by the special functional additives on the surface of the high-temperature resistant fiber cloth act as anchoring agents, slowing down the flow of high heat flux. Therefore, the thermal insulation material has good flexibility and good high heat flux resistance. As the silicone rubber content increases, the flexibility of the flexible composite material of the hot-surface layer increases, but the content of special functional additives decreases to the point that the density of the formed ceramic particles is insufficient to provide an anchoring effect, resulting in a decrease in high heat flux resistance. Conversely, a decrease in silicone rubber content reduces the flexibility of the flexible composite material of the hot-surface layer, while an increase in the content of special functional additives increases the interface between the functional additives and silicone rubber, causing the layer to lose its hydrophobicity.

[0103] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

[0104] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

Claims

1. A flexible thermal insulation material resistant to high heat flux, characterized in that: It includes a flexible composite material for the thermal surface layer and an inner thermal insulation material. The inner thermal insulation material has a bottom surface, a top surface, and multiple connecting surfaces connected to the edges of the bottom and top surfaces. The flexible composite material for the thermal surface layer covers the other surfaces of the inner thermal insulation material except for the bottom surface. The flexible composite material with a hot surface layer includes a high-temperature resistant fiber cloth and a mixed slurry attached to the surface of the high-temperature resistant fiber cloth. The mixed slurry includes special functional additives and silicone rubber. The special functional additives are selected from gaseous nano-SiO2, gaseous Al2O3 powder, micron-sized SiC or ZrO2 powder. The high-temperature resistant fiber cloth has a mixed slurry of equal thickness applied to both sides. The double-sided equal-thickness toughening treatment of the high-temperature resistant fiber cloth includes: Design a double-layer positioning mold; The double-layer positioning mold includes a first layer mold and a second layer mold arranged sequentially from bottom to top. The upper surface of the first layer mold is provided with a groove, and the second layer mold is provided with a through hole facing the groove. A mixed slurry is placed in the groove of the first mold, and then a high-temperature resistant fiber cloth is laid on the surface of the first mold. The second mold is then placed on the high-temperature resistant fiber cloth. The edge of the high-temperature resistant fiber cloth is located outside the first and second molds to protect the edge of the high-temperature resistant fiber cloth. The second mold is provided with a through hole facing the position where the mixed slurry is attached to the high-temperature resistant fiber cloth. The mixed slurry is poured into the upper surface of the high-temperature resistant fiber cloth through the through hole. After calendering and curing, a hot-surface flexible composite material is obtained. The thickness of the flexible composite material of the thermal surface layer is 1-6mm, and the thickness of the inner thermal insulation material is not less than 2mm; The mass content of special functional additives in the mixed slurry is 0.08~8.5 wt%. The high-temperature resistant fiber cloth is selected from fiber cloth containing alumina or silicon carbide fiber cloth.

2. The high heat flux resistant flexible thermal insulation material according to claim 1, characterized in that: The high-temperature resistant fiber cloth has a single-sided edge with a width of 4-50mm at the edge where the mixed slurry is attached; based on the total mass of the mixed slurry and the high-temperature resistant fiber cloth with the mixed slurry attached as 100%, the mass content of the high-temperature resistant fiber cloth with the mixed slurry attached is 15.25-63.74wt%, and the mass content of the mixed slurry is 36.26-84.75wt%.

3. The high heat flux resistant flexible thermal insulation material according to claim 1, characterized in that: The inner insulation material includes ceramic fiber cloth, ceramic fiber cotton / felt / paper and continuous ceramic fiber yarn, which is used to sew together multiple layers of ceramic fiber cloth and multiple layers of ceramic fiber cotton / felt / paper.

4. The high heat flux resistant flexible thermal insulation material according to claim 3, characterized in that: Ceramic fiber cloth must contain fiber cloth with alumina or silicon carbide components; Ceramic fiber cotton / felt / paper must contain mullite fiber cotton / felt or zirconium oxide fiber paper; Continuous ceramic fiber yarn is selected from continuous alumina fiber yarn, continuous silicon carbide fiber yarn, or quartz fiber yarn.

5. The high heat flux resistant flexible thermal insulation material according to claim 3, characterized in that: The inner insulation material is laid in the following order from the hot surface layer to the cold surface layer: ceramic fiber cloth, ceramic fiber cotton / felt / paper and ceramic fiber cloth. The ceramic fiber cloth near the hot surface layer is made of fiber cloth containing alumina or silicon carbide fiber cloth, and the ceramic fiber cloth near the cold surface layer is made of fiber cloth containing alumina, silicon carbide fiber cloth or quartz fiber cloth.

6. A method for preparing a flexible thermal insulation material resistant to high heat flux, characterized in that: include S1: Mix the special functional additives with silicone rubber evenly to form a mixed slurry; S2: Based on the preset thickness of the hot surface flexible composite material, select a double-layer positioning mold of appropriate thickness, perform double-sided equal-thickness toughening treatment on the high-temperature resistant fiber cloth, and obtain the hot surface flexible composite material after curing. S3: Lay out and sew ceramic fiber cloth, ceramic fiber cotton / felt / paper to obtain inner insulation material; S4: The flexible composite material of the hot surface layer and the inner thermal insulation material are stitched together on all four sides to obtain a high heat flux resistant flexible thermal insulation material as described in any one of claims 1-5.