Hot-press-formed non-woven thermal insulation fabric and preparation method therefor

Abstract

The present application relates to the technical field of non-woven materials, and specifically discloses a hot-press-formed non-woven thermal insulation fabric and a preparation method therefor. The hot-press-formed non-woven thermal insulation fabric is obtained by stacking a plurality of fabric units and then edge-sealing the stacked structure, each fabric unit is formed by vertically stacking two base fabrics, a plurality of spaced protrusions are provided on each base fabric, and the protrusions on the two base fabrics in each fabric unit face each other. Each base fabric is made of the following raw materials in parts by weight: 90-110 parts of aramid fiber; and 4-8 parts of modified bamboo fiber. The modified bamboo fiber is prepared by the following steps: S1, dispersing a carbon nanotube raw material in deionized water, adding a bamboo fiber slurry and mixing, then adding an N-methylmorpholine aqueous solution and uniformly mixing, and performing viscose spinning to obtain a fiber substrate; and S2, immersing the fiber substrate in a borax solution for treatment, taking out the fiber substrate, and then drying to obtain the modified bamboo fiber. The hot-press-formed non-woven thermal insulation fabric of the present application maintains excellent thermal insulation stability under sharp and frequent temperature fluctuations.

Description

A thermoforming nonwoven thermal insulation fabric and its preparation method Technical Field

[0001] This application relates to the field of nonwoven materials technology, and more specifically, to a hot-pressed nonwoven thermal insulation fabric and its preparation method. Background Technology

[0002] Nonwoven fabrics are fabrics formed without spinning or weaving. They are made by orienting or randomly arranging short or long textile fibers to form a web structure, which is then reinforced by mechanical, thermal bonding, or chemical methods. They are a new type of fiber product with a soft, breathable, and planar structure, formed directly from polymer chips, short fibers, or filaments through various web forming methods and consolidation techniques. Due to their lightweight, softness, and breathability, they are widely used in many fields.

[0003] Currently, the commonly used methods to improve the thermal insulation performance of nonwoven materials mainly involve enhancing the thermal insulation effect through material selection and multi-layer composite structure design. High-quality thermal insulation materials should have low thermal conductivity, meaning that the material itself does not easily conduct heat. Materials such as polyester, nylon, and polypropylene can be selected, as these materials have good thermal insulation performance. Multi-layer composite structure design increases the thickness of the thermal insulation material, because a thicker insulation layer can provide a longer heat transfer path, thereby reducing the rate of heat loss and thus improving the thermal insulation performance.

[0004] Regarding the aforementioned technologies, the inventors believe that the stable and excellent thermal insulation performance of nonwoven fabrics requires tight connections between their internal structures. However, in practical applications, due to the influence of drastic and frequent temperature changes, the structure of nonwoven fabrics inevitably becomes loose. When the looseness of the structure is severe, it will lead to a significant reduction in the thermal insulation performance of the nonwoven fabric, thereby significantly reducing its service life.

[0005] Therefore, there is an urgent need to propose a solution to address the aforementioned technical problems. Summary of the Invention

[0006] In order to improve the thermal insulation performance stability of nonwoven fabrics under the influence of drastic and frequent temperature changes, this application provides a hot-pressed nonwoven thermal insulation fabric and its preparation method.

[0007] In a first aspect, this application provides a thermoformed nonwoven thermal insulation fabric, employing the following technical solution: A thermoformed nonwoven thermal insulation fabric is obtained by stacking and sealing multiple fabric units, wherein each fabric unit is formed by stacking two base fabrics one on top of the other, the base fabrics having multiple spaced protrusions, and the protrusions on the two base fabrics in the fabric unit being arranged opposite each other; the base fabrics are made of the following raw materials in parts by weight: 90-110 parts of aramid fiber; 4-8 parts of modified bamboo fiber; the modified bamboo fiber is prepared by the following steps: S1, dispersing carbon nanotube raw materials in deionized water, adding bamboo fiber slurry and mixing, then adding N-methylmorpholine aqueous solution and mixing evenly, and obtaining a fiber substrate by viscose spinning; S2, immersing the fiber substrate obtained in step S1 in a borax solution for treatment, removing it and drying it to obtain modified bamboo fiber.

[0008] By adopting the above technical solution, the protrusions on the two base fabrics in the fabric unit are arranged opposite each other, so that a gap is formed between the base fabrics, which is an air layer. These air layers form multiple layered heat insulation spaces in the hot-pressed nonwoven insulation fabric. Since air is a very good poor conductor of heat, it can effectively slow down the convection and radiation transfer of heat, and build a highly efficient heat insulation barrier.

[0009] Aramid fiber is used as the main raw material in the base fabric. Because aramid fiber has high strength, high modulus and high temperature resistance, it can effectively insulate against external heat and cold and provide good heat insulation. Moreover, aramid fiber also has excellent mechanical properties, such as high strength, high modulus and good toughness. These properties enable aramid fiber to not only provide good heat insulation in the fabric, but also increase the durability and comfort of the fabric. Modified bamboo fiber has numerous micropores, which effectively isolate low-temperature air from the outside, forming a better insulation layer. The carbon nanotubes doped in it not only have excellent thermal conductivity but also excellent structural support and stabilization. Under the influence of drastic and frequent temperature changes, the modified bamboo fiber can improve the structural stability of thermoformed nonwoven insulation fabrics. At the same time, the treatment with borax solution coats the surface of the modified bamboo fiber with a layer of fluffy borax. In addition to protecting the stability of the bamboo-based material, it can also work with carbon nanotubes to play an excellent role in temperature change resistance and structural stability in the structural system of thermoformed nonwoven insulation fabrics. This significantly improves the thermal insulation performance stability of thermoformed nonwoven insulation fabrics under the influence of drastic and frequent temperature changes.

[0010] Preferably, in the preparation of the modified bamboo fiber, the weight percentage of carbon nanotubes in the fiber substrate is 3-5%.

[0011] By adopting the above technical solution, the carbon nanotubes at the above weight ratio can play an excellent and stable role in the hot-pressed nonwoven thermal insulation fabric. At the same time, the modified bamboo fiber with the weight ratio of carbon nanotubes also has uniform and numerous micropores, which makes the overall effect of the application of modified bamboo fiber better. Finally, the thermal insulation performance of the hot-pressed nonwoven thermal insulation fabric is more stable under the influence of drastic and frequent temperature changes.

[0012] Preferably, in the preparation of the modified bamboo fiber, the borax solution has a mass fraction of 6-10%.

[0013] By adopting the above technical solution, the borax solution of the above mass fraction can ensure that the surface of the modified bamboo fiber can be uniformly coated with a layer of fluffy borax after application, and the coating structure is relatively stable. During the application process, it can exert a better synergistic effect with carbon nanotubes, thereby making the application of modified bamboo fiber more effective.

[0014] Preferably, the aramid fiber is pretreated before application, including the following steps: immersing the aramid fiber in a dopamine solution, then removing it, washing and drying it, adding it to a Tris-HCl buffer solution, then adding aminated graphene oxide, stirring and reacting, and finally washing and drying it.

[0015] By adopting the above technical solution, during treatment in a dopamine solution, a polydopamine coating is deposited on the surface of aramid fibers by utilizing the oxidative self-polymerization of dopamine. This not only improves the interfacial properties of aramid fibers but also utilizes the secondary reaction properties of polydopamine to further form a graphene oxide coating after introducing aminated graphene oxide. As a result, the pretreated aramid fibers exhibit superior thermal insulation performance after application, and their stability under frequent temperature changes is significantly improved. Consequently, the resulting thermoformed nonwoven thermal insulation fabric is less prone to structural loosening under frequent temperature changes, resulting in significantly improved overall application stability.

[0016] Preferably, the concentration of the dopamine solution is 1.8-2.2 g / L.

[0017] Preferably, the amount of aminated graphene oxide is 1-3% of the weight of the aramid fiber.

[0018] By adopting the above technical solution, the polydopamine coating formed by the dopamine solution of the above concentration can form a relatively uniform and complete coverage on the surface of aramid fibers after application. At the same time, after introducing aminated graphene oxide, it can also react relatively uniformly and form a uniform and stable graphene oxide coating. The above-mentioned weight of methylated graphene oxide can also achieve a relatively complete coverage. Thus, the pretreated aramid fibers exhibit better corresponding effects after application.

[0019] Preferably, the aramid fiber comprises the following components in parts by weight: 75-85 parts of meta-aramid fiber; and 15-25 parts of para-aramid fiber.

[0020] By adopting the above technical solution, meta-aramid fiber, officially known as "poly(m-phenylene isophthalamide)" fiber, commonly known as aramid 1313, has a linear zigzag molecular chain, a high glass transition temperature, and flexibility, making it perform well in textile processing. Para-aramid fiber, commonly known as aramid 1414, has excellent properties such as high strength, high modulus, high temperature resistance, and flame retardancy. Its molecular chain is linear, enabling it to withstand huge tensile forces without easily breaking. By using meta-aramid fiber and para-aramid fiber in the above weight proportions, not only can excellent thermal insulation effects be achieved, but they can also complement each other's advantages, ensuring that the final thermo-pressed nonwoven thermal insulation fabric has better application quality.

[0021] Secondly, this application provides a method for preparing a thermoformed nonwoven thermal insulation fabric, which adopts the following technical solution: A method for preparing a thermoformed nonwoven thermal insulation fabric includes the following steps: (1) preparing raw materials containing aramid fiber and modified bamboo fiber according to the ratio; (2) loosening the aramid fiber and modified bamboo fiber in step (1) by using an opening machine, and then arranging the fibers into a mesh structure by a carding process to obtain a formed fiber web; (3) after pre-wetting treatment, the formed fiber web in step (2) is reinforced by a forward and reverse hydroentangling process, and then dried to obtain a semi-finished fabric; (4) the semi-finished fabric in step (3) is thermoformed to obtain a base fabric, and then two base fabrics are stacked on top of each other to form a fabric unit, and multiple fabric units are stacked and then sealed to obtain a finished product.

[0022] By adopting the above technical solution, the overall operation is relatively simple, and it allows the raw materials to fully cooperate and form a stable structural bond, ultimately resulting in a product of better quality. The pre-wetting treatment aims to compact the loose structure of the fiber web, expel air, and ensure that the fiber web can efficiently absorb the energy of the water jet during the forward and reverse hydroentangling process, thereby enhancing the entanglement effect between fibers. The hot-pressing process not only makes the fabric surface smoother but also forms multiple spaced protrusions on the base fabric. Simultaneously, according to actual needs, an appropriate number of fabric units can be selected, stacked, and edge-sealed to obtain the finished product, resulting in strong overall applicability.

[0023] Preferably, in the hot pressing process of step (4), the hot pressing pressure is 15-20 MPa, the hot pressing temperature is 250-270°C, the hot pressing is performed twice, and the hot pressing time for each time is 15-18 seconds.

[0024] By adopting the above technical solutions, the choice of temperature affects the material's plastic deformation ability and shape retention ability, the choice of pressure affects the material's filling degree and molding density, and the choice of heat preservation time affects the material's feel and appearance. The control of the above parameters enables the fabric fibers to achieve structural optimization and performance upgrade during the process of forming special shapes, ultimately obtaining high-quality thermoformed nonwoven thermal insulation fabric.

[0025] In summary, this application has the following beneficial effects: 1. By incorporating modified bamboo fiber into aramid fiber, this application utilizes the structural support and stabilizing effect of modified bamboo fiber, combined with the structural characteristics of the numerous fine pores in modified bamboo fiber, to form a better insulation layer. This improves the structural stability of the thermoformed nonwoven insulation fabric under the influence of drastic and frequent temperature changes. 2. By pretreating the aramid fiber before application, and through the combination of polydopamine coating and graphene oxide coating formed on its surface, the pretreated aramid fiber exhibits superior insulation performance after application. The resulting thermoformed nonwoven insulation fabric is less prone to significant structural loosening under frequent temperature changes, and its overall application stability is significantly improved. Detailed Implementation

[0026] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0027] Unless otherwise specified, all raw materials used in the preparation examples, embodiments, and comparative examples of this application are commercially available: meta-aramid fibers and para-aramid fibers were purchased from DuPont, USA; carbon nanotubes were purchased from Suzhou Kaifa New Material Technology Co., Ltd. (CNTs-006-2H hydroxylated multi-walled carbon nanotubes); bamboo fiber pulp was purchased from Shaowu Bamboo Pulp Factory in Fujian Province; N-methylmorpholine aqueous solution was purchased from Shanghai Baishun Biotechnology Co., Ltd. (N-methylmorpholine-N-oxide 7529-22-8 50% aqueous solution, 100ML specification); dopamine solution was obtained by mixing sodium carbonate-sodium bicarbonate buffer solution (pH=8.5) with dopamine hydrochloride, which was purchased from Sigma (dopamine hydrochloride, catalog number H8502-100G); aminated graphene oxide was purchased from Dihedron (Shanghai) Technology Co., Ltd. (model GP89A-D).

[0028] Preparation Example of Raw Materials and / or Intermediates Preparation Example 1 A modified bamboo fiber is prepared by the following steps: S1. Carbon nanotube raw material is dispersed in deionized water, and bamboo fiber slurry with 8 times the weight of carbon nanotube raw material is added and mixed. Then, N-methylmorpholine aqueous solution with 1 / 10 the weight of bamboo fiber slurry is added and mixed evenly. The mixture is then spun with viscose to obtain a fiber substrate; S2. The fiber substrate obtained in step S1 is immersed in borax solution and treated at 25°C for 30 min. After being removed and dried, the modified bamboo fiber is obtained.

[0029] Note: In the above operation, the carbon nanotubes in the fiber substrate account for 3-5% by weight; the borax solution has a mass fraction of 6-10%; and the modified bamboo fiber has a diameter of 0.05 mm and a length of 6 cm.

[0030] Preparation Example 2: A modified bamboo fiber, which differs from Preparation Example 1 in that the carbon nanotubes in the fiber matrix account for 3-5% by weight.

[0031] Preparation Example 3: A modified bamboo fiber, which differs from Preparation Example 1 in that the carbon nanotubes in the fiber matrix account for 3-5% by weight.

[0032] Preparation Example 4: A modified bamboo fiber, which differs from Preparation Example 1 in that the borax solution has a mass fraction of 6-10%.

[0033] Preparation Example 5: A modified bamboo fiber, which differs from Preparation Example 1 in that the borax solution has a mass fraction of 6-10%.

[0034] Preparation Example 6 A modified bamboo fiber, which differs from Preparation Example 1 in that it is prepared by the following steps: S1, carbon nanotube raw material is dispersed in deionized water, bamboo fiber slurry with 8 times the weight of carbon nanotube raw material is added and mixed, and then N-methylmorpholine aqueous solution with 1 / 10 the weight of bamboo fiber slurry is added and mixed evenly, and modified bamboo fiber is obtained by viscose spinning.

[0035] Preparation Example 7: A modified bamboo fiber, differing from Preparation Example 1, is prepared through the following steps: S1: Take bamboo fiber slurry, add one-tenth the weight of N-methylmorpholine aqueous solution to the bamboo fiber slurry, mix thoroughly, and obtain a fiber substrate by viscose spinning; S2: Immerse the fiber substrate obtained in step S1 in a borax solution at 25°C for 30 minutes, remove and dry to obtain modified bamboo fiber. Examples

[0036] Example 1 A thermoformed nonwoven thermal insulation fabric is obtained by stacking and sealing multiple fabric units. Each fabric unit is formed by stacking two base fabrics on top of each other. Multiple square protrusions are evenly arranged on the base fabrics, and the protrusions on the two base fabrics in the fabric unit are arranged opposite each other. The composition and corresponding weight of the base fabrics are shown in Table 1. The composition and corresponding weight of the aramid fiber are shown in Table 2. The thermoformed nonwoven thermal insulation fabric is prepared by the following steps: (1) Prepare raw materials containing aramid fiber and modified bamboo fiber according to the ratio; (2) After loosening the aramid fiber and modified bamboo fiber in step (1) by opening machine, arrange the fibers into a mesh structure by carding process to obtain the formed fiber web; (3) After pre-wetting treatment, the formed fiber web in step (2) is reinforced by forward and reverse hydroentangling process and dried to obtain semi-finished fabric. (4) The semi-finished fabric in step (3) is hot-pressed to obtain a base fabric. The two base fabrics are then stacked on top of each other to form a fabric unit. Multiple fabric units are stacked and then sealed to obtain the finished product.

[0037] Note: In the above operation, the hot pressing pressure was 17.5 MPa, the hot pressing temperature was 260℃, the hot pressing was performed twice, and the hot pressing time for each time was 16.5 seconds; three fabric units were selected, and the weight of the resulting hot-pressed nonwoven thermal insulation fabric was 260 g / m². 2 The modified bamboo fiber was obtained from Preparation Example 1.

[0038] Examples 2-3: A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the components of the base fabric and their corresponding weights are shown in Table 1.

[0039] Table 1. Components and weight percentages (kg / part) of the base fabrics in Examples 1-3. Examples 4-5: A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the composition of the aramid fiber and its corresponding weight are shown in Table 2. Table 2: Composition of aramid fiber and its weight parts (kg / part) in Examples 1, 4, and 5. Example 6: A thermoforming nonwoven thermal insulation fabric, which differs from Example 1 in that the thermoforming process involves a thermoforming pressure of 15 MPa, a thermoforming temperature of 250°C, two thermoforming cycles, and a thermoforming time of 15 seconds for each cycle.

[0040] Example 7: A thermoforming nonwoven thermal insulation fabric, which differs from Example 1 in that the thermoforming process involves a thermoforming pressure of 20 MPa, a thermoforming temperature of 270°C, two thermoforming cycles, and a thermoforming time of 18 seconds for each cycle.

[0041] Example 8: A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the modified bamboo fiber is obtained from Preparation Example 2.

[0042] Example 9 A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the modified bamboo fiber is obtained from Preparation Example 3.

[0043] Example 10: A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the modified bamboo fiber is obtained from Preparation Example 4.

[0044] Example 11 A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the modified bamboo fiber is obtained from Preparation Example 5.

[0045] Example 12 A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the aramid fiber is pretreated before application, including the following steps: The aramid fiber is immersed in 8 times its volume of dopamine solution and treated at 25°C for 24 hours. After being taken out, washed and dried, it is added to Tris-HCl buffer solution, and then aminated graphene oxide is added. After stirring and reacting at 30°C for 15 hours, it is washed and dried to obtain the final product.

[0046] Note: In the above operation, the concentration of dopamine solution is 2 g / L; the amount of aminated graphene oxide used is 2% of the weight of aramid fiber.

[0047] Example 13: A thermoformed nonwoven thermal insulation fabric, which differs from Example 12 in that the concentration of the dopamine solution is 1.8 g / L.

[0048] Example 14: A thermoformed nonwoven thermal insulation fabric, which differs from Example 12 in that the concentration of the dopamine solution is 2.2 g / L.

[0049] Example 15: A thermoformed nonwoven thermal insulation fabric, which differs from Example 12 in that the amount of aminated graphene oxide used is 1% of the weight of the aramid fiber.

[0050] Example 16: A thermoformed nonwoven thermal insulation fabric, which differs from Example 12 in that the amount of aminated graphene oxide used is 3% of the weight of the aramid fiber.

[0051] Comparative Example 1: A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that modified bamboo fiber is not used in the composition of the base fabric.

[0052] Comparative Example 2: A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the modified bamboo fiber was obtained from Preparation Example 6.

[0053] Comparative Example 3: A thermoformed nonwoven thermal insulation fabric, which differs from Example 1 in that the modified bamboo fiber was obtained from Preparation Example 7.

[0054] Performance testing test samples: The hot-pressed nonwoven thermal insulation fabrics obtained in Examples 1-16 were used as test samples 1-16, and the hot-pressed nonwoven thermal insulation fabrics obtained in Comparative Examples 1-3 were used as control samples 1-3.

[0055] Test Method: ASTM D7984 is a standard test method for measuring the thermal conductivity of fabrics, particularly suitable for evaluating their insulation performance. ASTM D7984 employs a modified transient planar heat source method (MTPS), applying a momentary constant heat source to the sample surface via a single-sided thermal sensor; the test duration is typically 1-3 seconds. When performing ASTM D7984 testing, a C-Therm TCi thermal conductivity meter is used. This method allows for rapid, non-destructive measurement of the fabric's heat dissipation rate. The heat dissipation rate refers to the rate at which heat is transferred through a material; it reflects the material's ability to conduct heat. A higher heat dissipation rate indicates poorer insulation performance.

[0056] The hot-pressed nonwoven insulation fabric was tested according to the above method, and the heat dissipation rate was recorded as the initial value A. Then, the hot-pressed nonwoven insulation fabric was placed in a high and low temperature alternating test chamber with an initial temperature of 25℃. The temperature was first increased to 65℃ at 2℃ / min, then decreased to -10℃ at 1.5℃ / min, and then increased to 25℃ at 1℃ / min, which was recorded as 1 cycle. After 20 cycles, the above test was performed in the same way, and the heat dissipation rate was recorded as the termination value B. Finally, the insulation performance loss rate was calculated as follows: insulation performance loss rate = (termination value B - initial value A) / initial value A. The larger the insulation performance loss rate, the more likely the structure of the hot-pressed nonwoven insulation fabric is to become loose under the influence of drastic and frequent temperature changes, and the poorer the structural stability.

[0057] After performing the above tests on test samples 1-16 and control samples 1-3 in sequence, the corresponding results are recorded in Table 3.

[0058] Table 3 Test results of test samples 1-16 and control samples 1-3 As can be seen from Examples 1-3 and Comparative Examples 1-3, and Table 2, the use of modified bamboo fiber in this application significantly reduces the thermal insulation performance loss rate of the final thermo-pressed nonwoven insulation fabric after the above tests. This indicates that under the influence of drastic and frequent temperature changes, modified bamboo fiber provides excellent structural support and stability, thereby ensuring the fabric's excellent thermal insulation performance. Furthermore, while using only carbon nanotubes or borax solution in the preparation of modified bamboo fiber can improve the stability of thermal insulation performance, the improvement effect is limited, and the sum of their individual effects is far less than the superior effect of their combination. Therefore, the layer of fluffy borax coating on the surface of the modified bamboo fiber can exert an excellent synergistic effect with carbon nanotubes in the structural system of the thermo-pressed nonwoven insulation fabric, significantly improving the thermal insulation performance stability of the thermo-pressed nonwoven insulation fabric under the influence of drastic and frequent temperature changes.

[0059] As can be seen from Examples 1 and 4-5 and Table 2, the combined use of meta-aramid fibers and para-aramid fibers can both produce high-performance and stable thermoformed nonwoven thermal insulation fabrics.

[0060] Combining Examples 1 and 6-7 with Table 2, it can be seen that in the hot pressing process of step (4), controlling the hot pressing pressure to be 15-20 MPa, the hot pressing temperature to be 250-270℃, the number of hot pressing cycles to be 2, and the hot pressing time for each cycle to be 15-18 seconds, can all result in a high-quality hot-pressed nonwoven thermal insulation fabric.

[0061] As can be seen from Examples 1 and 8-11 and Table 2, the modified bamboo fibers prepared in this application can all be combined with aramid fibers to finally produce hot-pressed nonwoven thermal insulation fabrics that can maintain stable thermal insulation performance under frequent temperature changes.

[0062] As can be seen from Examples 1 and 12-16 and Table 2, by pretreating the aramid fibers before application, and through the combination of the polydopamine coating and graphene oxide coating formed on their surface, the pretreated aramid fibers exhibit better thermal insulation performance after application. The thermal insulation performance loss rate of the obtained hot-pressed nonwoven thermal insulation fabric is further significantly reduced after the above tests, indicating that the thermal insulation stability of the fabric is further improved.

[0063] 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 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 thermoformed nonwoven thermal insulation fabric, characterized in that, It is obtained by stacking multiple fabric units and then sealing the edges. The fabric unit is formed by stacking two base fabrics one on top of the other. The base fabrics are provided with multiple spaced protrusions, and the protrusions on the two base fabrics in the fabric unit are arranged opposite each other. The base fabric is made from the following raw materials in parts by weight: 90-110 parts of aramid fiber; 4-8 parts modified bamboo fiber; The modified bamboo fiber was prepared through the following steps: S1. Disperse carbon nanotube raw materials in deionized water, add bamboo fiber slurry and mix, then add N-methylmorpholine aqueous solution and mix evenly, and obtain fiber substrate by viscose spinning; S2. The fiber substrate obtained in step S1 is immersed in a borax solution for treatment, then removed and dried to obtain modified bamboo fiber.

2. The thermoformed nonwoven thermal insulation fabric according to claim 1, characterized in that: In the preparation of the modified bamboo fiber, the weight percentage of carbon nanotubes in the fiber substrate is 3-5%.

3. The hot-pressed nonwoven thermal insulation fabric according to claim 1, characterized in that: In the preparation of the modified bamboo fiber, the borax solution has a mass fraction of 6-10%.

4. The hot-pressed nonwoven thermal insulation fabric according to claim 1, characterized in that: The aramid fibers undergo pretreatment before application, including the following steps: Aramid fibers were immersed in a dopamine solution for treatment, then removed, washed and dried, and then added to a Tris-HCl buffer solution. Aminated graphene oxide was then added, and after stirring and reacting, the fibers were washed and dried to obtain the final product.

5. The thermoformed nonwoven thermal insulation fabric according to claim 4, characterized in that: The concentration of the dopamine solution is 1.8-2.2 g / L.

6. The hot-pressed nonwoven thermal insulation fabric according to claim 4, characterized in that: The amount of aminated graphene oxide used is 1-3% of the weight of the aramid fiber.

7. The hot-pressed nonwoven thermal insulation fabric according to claim 1, characterized in that: The aramid fiber comprises the following components in parts by weight: 75-85 parts of meta-aramid fiber; 15-25 parts of para-aramid fiber.

8. The method for preparing the hot-pressed nonwoven thermal insulation fabric according to claim 1, characterized in that: Includes the following steps: (1) Prepare raw materials containing aramid fiber and modified bamboo fiber according to the formula; (2) After the aramid fiber and modified bamboo fiber in step (1) are loosened by an opening machine, the fibers are arranged into a mesh structure by a carding process to obtain a shaped fiber web. (3) After the fiber web formed in step (2) is pre-wetted, it is reinforced by the forward and reverse hydroentangling process and then dried to obtain a semi-finished fabric. (4) The semi-finished fabric in step (3) is hot-pressed to obtain a base fabric. The two base fabrics are then stacked on top of each other to form a fabric unit. Multiple fabric units are stacked and then sealed to obtain the finished product.

9. The method for preparing the hot-pressed nonwoven thermal insulation fabric according to claim 8, characterized in that: In step (4) hot pressing, the hot pressing pressure is 15-20 MPa, the hot pressing temperature is 250-270℃, the hot pressing is performed twice, and the hot pressing time is 15-18 seconds each time.

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