Aerogel heat insulation sheet, normal-temperature and normal-pressure preparation method and application of aerogel heat insulation sheet

Abstract

The invention belongs to the technical field of aerogel heat insulation materials, and particularly discloses an aerogel heat insulation sheet, a normal-temperature and normal-pressure preparation method and application of the aerogel heat insulation sheet, and the method comprises the steps that firstly, titanium dioxide and trimethylethoxysilane are mixed and stirred to be uniform, and mixed liquid is formed; then, mixing and stirring the mixed liquid and tetraethoxysilane to form composite sol; then, shower-coating the composite sol on a glass fiber base material to obtain aerogel-glass fiber composite gel; the composite gel is put into an alkaline silicon solution to be aged for 48 h, then pretreatment drying is conducted, then the composite gel is transferred into a drying oven to be dried, and finally the aerogel heat insulation sheet is obtained. And finally, testing the heat insulation performance of the product. The method has the advantages of easily available raw materials, simple process, low cost and the like, and the aerogel heat insulation sheet prepared by the method has excellent heat insulation performance, stable structure and good mechanical strength, and can be widely applied to the fields of building heat insulation, electronic equipment heat dissipation protection or industrial pipeline heat insulation and the like.

Description

Technical Field

[0001] This invention belongs to the technical field of aerogel insulation materials, and particularly relates to an aerogel insulation sheet, a method for its preparation at room temperature and pressure, and its application. Background Technology

[0002] Aerogels, as a novel lightweight material with a nanoscale porous network structure, have become one of the best-performing solid materials known to date due to their extremely high porosity and extremely low thermal conductivity. Their excellent thermal insulation properties, low density, and high-temperature resistance make them promising for a wide range of applications in building insulation, aerospace, electronic equipment heat dissipation, and industrial pipeline insulation. However, the large-scale production and practical application of aerogels have long been limited by the complexity of their preparation processes.

[0003] The core bottleneck in traditional aerogel preparation processes lies in the drying stage, which generally relies on supercritical drying technology. Supercritical drying requires operation under high temperature and high pressure conditions, placing extremely stringent demands on equipment. This not only requires a huge investment in specialized high-pressure containers but also results in extremely high energy consumption. During operation, temperature and pressure parameters must be precisely controlled; any slight deviation can lead to gel structure collapse or product spoilage, making the entire process cumbersome and with low tolerance for error. These factors collectively drive up production costs, severely restricting the large-scale industrial application of aerogels.

[0004] To overcome the limitations of supercritical drying, researchers have turned to developing room temperature and pressure drying technologies. However, existing room temperature and pressure preparation methods still have significant drawbacks. Some methods require the addition of expensive modifiers, such as specific silane compounds, to improve the structural stability of aerogels, which directly increases raw material costs. Other methods use large amounts of organic solvents as reaction media, which not only raises production costs but also introduces additional environmental treatment burdens and safety risks. Furthermore, many aerogels prepared at room temperature and pressure have undesirable microstructures, exhibiting loose network connections and insufficient mechanical strength, making them prone to cracking or breakage during routine handling, installation, or use, failing to meet the strength requirements of practical engineering projects. The control of process parameters is also extremely sensitive; even slight fluctuations in pH, stirring speed, and time can lead to product performance fluctuations, resulting in poor batch stability, low production efficiency, and an inability to meet the demands of continuous mass production.

[0005] At the application level, aerogel insulation materials also face the challenge of weak bonding with substrates. When aerogel is coated onto substrates such as glass fiber, poor interfacial compatibility and weak adhesion can easily lead to delamination under long-term thermal cycling or mechanical vibration. This not only weakens the overall insulation performance but may also cause localized material failure. Furthermore, the insulation performance of aerogels often gradually declines over time, primarily due to the slow collapse of their nanoporous structure under environmental influences, further affecting service life and reliability. Existing technologies have limited means to control the microstructure of aerogels, making it difficult to achieve synergistic optimization of insulation performance and structural stability while simplifying processes and reducing costs.

[0006] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0007] The purpose of this invention is to provide an aerogel insulation sheet, a method for its preparation at room temperature and pressure, and its application. This method has the advantages of readily available raw materials, simple process, no need for supercritical drying equipment, and low cost. The aerogel insulation sheet prepared by this method has excellent thermal insulation performance, stable structure, and good mechanical strength, and can be widely used in building insulation, heat dissipation protection of electronic equipment, or thermal insulation of industrial pipelines.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: a method for preparing aerogel insulation sheets at room temperature and pressure, comprising the following steps:

[0009] S1. Preparation of the mixed liquid: Take a set mass of trimethylethoxysilane, and add titanium dioxide at 1% of the mass of trimethylethoxysilane to the set mass of trimethylethoxysilane. Stir evenly to form a mixed liquid.

[0010] S2. Preparation of composite sol: The mixed liquid obtained in step S1 is mixed with tetraethyl orthosilicate at a volume percentage ratio of 1:2 and stirred evenly to obtain composite sol.

[0011] S3. Gel molding: The composite sol obtained in step S2 is uniformly coated onto the glass fiber substrate and left to stand at room temperature. After the composite sol has completely gelled, an aerogel-glass fiber composite gel body is obtained.

[0012] S4. Aging treatment: The aerogel-glass fiber composite gel obtained in step S3 is placed in an alkaline silica solution and soaked for aging for 48 hours.

[0013] S5. Drying treatment: Place the aerogel-glass fiber composite gel after the aging treatment in step S4 into a microwave drying device and heat for 10 minutes; then transfer the gel-glass fiber composite gel after heating to an oven and dry at 80°C to obtain an aerogel heat insulation sheet.

[0014] S6. Performance Testing: Conduct thermal insulation performance tests on the dried aerogel insulation sheet to evaluate its thermal insulation effect.

[0015] Furthermore, in step S1, the stirring speed is 400-500 r / min, and the stirring time is 15-25 min.

[0016] Furthermore, in step S1, the titanium dioxide has a particle size of 50-100 nm and a purity of ≥99.5%.

[0017] Furthermore, in step S2, the pH value of tetraethyl orthosilicate is 5.5-6.0; the mixing speed is 400-500 r / min, and the mixing time is 20-30 min.

[0018] Furthermore, in step S3, the glass fiber substrate is silica glass fiber with a thickness of 1.5-1.7 mm and a surface density of 80-120 g / m²; the coating amount of the composite sol is 200-300 g / m², and the standing time at room temperature is 15-20 min.

[0019] Furthermore, in step S4, the alkaline silicon solution is a mixture of sodium silicate aqueous solution and sodium hydroxide aqueous solution, wherein the concentration of sodium silicate is 0.5-1.0 mol / L and the pH value of the alkaline silicon solution is 10-12; during the aging process, the solution temperature is maintained at 25-30℃, and the alkaline silicon solution is replaced every 12 hours.

[0020] Furthermore, in step S5, the heating power of the microwave drying device is 100-200W; the drying time in the oven is 2-4 hours, and ventilation is maintained inside the oven during the drying process.

[0021] Furthermore, in step S6, the thermal insulation performance test adopts the steady-state plate method, with a test temperature range of 25-200℃ and a test ambient humidity of 40-60% RH; the thermal insulation temperature of qualified products is ≥130℃.

[0022] The present invention also discloses an aerogel heat insulation sheet prepared according to the aforementioned method.

[0023] The present invention also discloses the application of the aforementioned aerogel insulation sheet in building insulation, heat dissipation protection of electronic equipment, or heat insulation of industrial pipelines.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. Significantly reduced production costs: This invention uses readily available silica sol, titanium dioxide, and glass fiber substrate as raw materials, eliminating the need for expensive chemical modifiers or organic solvents. The drying process combines microwave pretreatment with oven drying, replacing traditional supercritical drying. This eliminates the need to invest in expensive supercritical drying equipment, significantly reducing equipment costs and energy consumption. It also shortens the production cycle, further reducing production costs and laying the foundation for the large-scale application of aerogel insulation sheets.

[0026] 2. Excellent product performance: Through titanium dioxide modification and alkaline silicon solution aging treatment, the prepared aerogel insulation sheet has good thermal insulation temperature difference and excellent thermal insulation performance; at the same time, it has good structural stability and mechanical strength, is not easy to crack or delaminate, and can adapt to the use requirements of different application scenarios; the introduction of glass fiber substrate further improves the product's flexibility and impact resistance, making it easy to handle, install and use.

[0027] 3. Simple and easy-to-operate process: The preparation process of this invention is simple and the process parameters are easy to control. No complicated professional technology and operating experience are required. The entire production process can be completed at room temperature and pressure. Only conventional stirring, coating, aging, microwave heating and oven drying equipment are required. The equipment requirements are low, which makes it easy for existing enterprises to carry out technical transformation and large-scale production.

[0028] 4. Wide range of applications: The aerogel insulation sheet prepared by the method of this invention has excellent thermal insulation performance, good mechanical strength and stability, and can be widely used in many fields such as building exterior wall insulation, interior wall insulation, heat dissipation protection of electronic equipment, industrial pipeline insulation, and automotive parts insulation, with broad market application prospects.

[0029] 5. Environmentally friendly: The raw materials used in this invention are all environmentally friendly materials. The water-based polyurethane resin and silica sol are both water-based systems with no volatile organic pollutant emissions. No toxic or harmful chemical reagents are used in the production process, and the amount of wastewater and exhaust gas emissions is small, which is environmentally friendly and in line with the development trend of green production.

[0030] In summary, compared with existing technologies, this invention uses tetraethyl orthosilicate and trimethylethoxysilane as main raw materials, titanium dioxide as a modifier, and glass fiber as a substrate. Through a process route of mixing, sol-gel, gelation, aging in alkaline silicon solution, microwave pretreatment combined with oven drying, aerogel insulation sheets are prepared. This achieves efficient preparation of aerogel insulation sheets at room temperature and pressure, solving the problems of high cost and poor stability of traditional supercritical drying processes, as well as insufficient structural strength of existing room temperature methods. It has advantages such as simplified process, reduced cost, improved stability, and enhanced mechanical strength. Attached Figure Description

[0031] Figure 1This is a schematic diagram of the preparation process of an aerogel insulation sheet prepared at room temperature and pressure according to the present invention.

[0032] Figure 2 This is a microscopic morphology image of the aerogel insulation sheet prepared based on the method of the present invention. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The basic implementation examples are as follows: Figure 1 The following is a method for preparing aerogel insulation sheets at room temperature and pressure, comprising the following steps:

[0036] S1. Preparation of the mixed liquid: Take a set mass of trimethylethoxysilane and add titanium dioxide at 1% of the mass of trimethylethoxysilane to the set mass of trimethylethoxysilane. Stir evenly at a stirring speed of 400-500 r / min for 15-25 min to form a mixed liquid. Specifically, trimethylethoxysilane is a silane coupling agent that can act as a silicon source during preparation and introduce hydrophobic groups, which helps reduce the surface tension during gel drying, thereby inhibiting the shrinkage and cracking of the gel skeleton. Titanium dioxide is an inorganic nanomaterial used as an additive in this method to regulate the microstructure and mechanical properties of the gel. Controlling the stirring speed within the range of 400-500 r / min provides sufficient shear force to ensure sufficient contact and uniform dispersion between trimethylethoxysilane and titanium dioxide, effectively preventing the agglomeration of titanium dioxide particles. If the stirring speed is too low, it may lead to insufficient mixing, affecting the dispersion of titanium dioxide; if the stirring speed is too high, it may introduce too much air or generate unnecessary turbulence, affecting the stability of the mixed liquid and even causing some components to volatilize. Setting the stirring time to 15-25 minutes ensures that titanium dioxide reaches a sufficient dissolved or dispersed state in trimethylethoxysilane, forming a stable mixed liquid. If the stirring time is too short, it may lead to incomplete mixing, resulting in uneven dispersion of titanium dioxide and affecting the uniformity of subsequent reactions; while if the stirring time is too long, it may cause unnecessary energy consumption and may even cause degradation or side reactions of some components, negatively impacting the quality of the mixed liquid. By adjusting the material ratio and precisely controlling the stirring speed and stirring time of the mixed liquid in step S1, it is possible to ensure that trimethylethoxysilane and titanium dioxide are fully and uniformly mixed, effectively avoiding the agglomeration of titanium dioxide caused by uneven mixing, thus ensuring the uniformity of the gel forming process, resulting in a more uniform microstructure and more stable thermal insulation performance in the final aerogel insulation sheet. In a preferred embodiment, the titanium dioxide has a particle size of 50-100 nm and a purity of ≥99.5%. Limiting the particle size to the 50-100 nm nanoscale range ensures excellent dispersibility in trimethylethoxysilane. Nanoscale titanium dioxide possesses a large specific surface area and surface energy, enabling better interaction with trimethylethoxysilane molecules, thus forming a stable and homogeneous liquid mixture and effectively preventing macroscopic agglomeration. Furthermore, titanium dioxide within this particle size range can act as an effective filler or reinforcing phase in the subsequent gelation process, uniformly distributing within the aerogel framework and positively impacting the microstructure and mechanical properties of the aerogel. Simultaneously, requiring a purity of ≥99.5% for the titanium dioxide minimizes the introduction of impurities. High-purity titanium dioxide avoids side reactions caused by impurities, ensuring a clear reaction pathway and pure products in subsequent steps between trimethylethoxysilane and tetraethyl orthosilicate.The presence of impurities can act as a defect source during the gelation process, affecting the uniformity and stability of the gel, and even leading to incomplete gel structure or abnormal pore structure. By strictly limiting the particle size and purity of titanium dioxide, the uniform dispersion of titanium dioxide in trimethylethoxysilane is ensured, effectively avoiding agglomeration and thus guaranteeing the stability and homogeneity of the mixed liquid.

[0037] S2. Preparation of the composite sol: The mixed liquid obtained in step S1 is mixed with tetraethyl orthosilicate at a volume ratio of 1:2 and stirred evenly to obtain the composite sol. Specifically, tetraethyl orthosilicate is a commonly used silicon source that forms a silica network structure through hydrolysis and condensation reactions, serving as a major precursor for the aerogel framework. The composite sol refers to a homogeneous colloidal solution formed by mixing trimethylethoxysilane, titanium dioxide, and tetraethyl orthosilicate, which undergoes a gelation reaction under specific conditions to form a solid gel. As a preferred embodiment, the pH value of tetraethyl orthosilicate, the mixing speed, and the stirring time are precisely controlled; wherein, the pH value of tetraethyl orthosilicate is 5.5-6.0; the mixing speed is 400-500 r / min, and the stirring time is 20-30 min. As a silicon source precursor, the hydrolysis and condensation reactions of tetraethyl orthosilicate are extremely sensitive to pH values. Maintaining the pH value within a weakly acidic to near-neutral range of 5.5-6.0 effectively optimizes the rates of hydrolysis and condensation reactions, promoting the formation of uniformly structured and stable silica sol particles. This avoids reaction runaway or byproduct formation due to excessively high or low pH values, thus providing a high-quality sol foundation for subsequent gelation. Simultaneously, using a stirring speed of 400-500 rpm during mixing ensures that the liquid mixture obtained in step S1 is fully and rapidly dispersed and uniformly mixed with tetraethyl orthosilicate, preventing localized high or low concentrations and ensuring synchronous reaction throughout the system. This stirring speed can be achieved using a mechanical stirrer or magnetic stirrer with speed adjustment. Continuing to stir for 20-30 minutes ensures sufficient time for the hydrolysis and condensation reactions of tetraethyl orthosilicate, allowing for the full formation and cross-linking of silanol groups, ultimately resulting in a stable and uniform composite sol, laying a solid foundation for subsequent gel formation.

[0038] S3. Gel Forming: The composite sol obtained in step S2 is uniformly coated onto a glass fiber substrate and allowed to stand at room temperature until the composite sol completely gels, resulting in an aerogel-glass fiber composite gel. In a preferred embodiment, the glass fiber substrate is silica glass fiber with a thickness of 1.5-1.7 mm and an areal density of 80-120 g / m². The coating amount of the composite sol is 200-300 g / m², and the standing time at room temperature is 15-20 minutes. Silica glass fiber is chosen as the substrate because it possesses excellent high-temperature resistance, chemical stability, and mechanical strength, providing a stable supporting framework for the aerogel and ensuring structural integrity during subsequent high-temperature treatment and practical applications, effectively avoiding performance degradation of the substrate under high-temperature or corrosive environments. Limiting the thickness of the glass fiber substrate to 1.5-1.7 mm aims to balance the overall thickness of the composite material, its mechanical strength, and the filling space of the aerogel. A substrate that is too thin may lack sufficient mechanical strength to support the gel structure; a substrate that is too thick may increase product weight and reduce the volume fraction of the aerogel, affecting the thermal insulation effect. This thickness range helps to form a composite structure with good mechanical and thermal insulation properties. Meanwhile, controlling the areal density of the glass fiber substrate at 80-120 g / m² ensures that the substrate has suitable porosity and fiber distribution. A lower areal density may result in an overly loose substrate structure, which is not conducive to the uniform penetration of the sol and the stable adhesion of the gel; while an excessively high areal density may result in excessively small pores in the substrate, hindering the full wetting of the sol and affecting the composite effect. This areal density range helps to achieve uniform distribution and full gelation of the sol within the substrate, thereby forming a dense and uniform composite gel. Furthermore, controlling the coating amount of the composite sol at 200-300 g / m² ensures that the glass fiber substrate can be fully wetted and filled, while avoiding waste due to excessive sol or drying difficulties due to an excessively thick gel layer. An appropriate coating amount ensures that the sol penetrates evenly into every corner of the substrate, forming a continuous and defect-free gel layer. This maximizes the thermal insulation performance of the aerogel and enhances its adhesion to the substrate. Based on this, a settling time of 15-20 minutes at room temperature is provided to allow sufficient time for the composite sol to complete the gelation reaction on the glass fiber substrate. Within this time range, the sol can fully cross-link to form a stable three-dimensional network structure, thus transforming into a wet gel with a certain strength. Too short a settling time may lead to incomplete gelation and a fragile gel structure; too long a settling time may lead to excessive gel shrinkage or surface drying, affecting subsequent processing. This settling time helps to form a uniform and stable aerogel-glass fiber composite gel.

[0039] S4. Aging Treatment: The aerogel-glass fiber composite gel obtained in step S3 is placed in an alkaline silica solution and soaked for aging for 48 hours. As a preferred embodiment, the alkaline silica solution is a mixture of sodium silicate aqueous solution and sodium hydroxide aqueous solution, wherein the concentration of sodium silicate is 0.5-1.0 mol / L and the pH value of the alkaline silica solution is 10-12. During the aging process, the solution temperature is maintained at 25-30℃, and the alkaline silica solution is replaced every 12 hours. Specifically, the aging treatment aims to enhance the skeletal strength of the gel by promoting further condensation reactions and cross-linking of silanol groups within the gel network, thereby effectively resisting the destructive effect of capillary forces during subsequent drying and reducing gel shrinkage. A mixture of sodium silicate and sodium hydroxide aqueous solutions is used as the alkaline silicon solution. The sodium hydroxide solution provides the necessary alkaline environment to catalyze the condensation reaction of silanol groups, while simultaneously promoting the dissolution and redeposition of the silicon framework. The sodium silicate solution acts as an additional soluble silicon source, replenishing silicon under alkaline conditions and allowing it to deposit at weak points or cross-linking points in the gel framework, further thickening the framework and strengthening the gel structure. The concentration of sodium silicate is controlled within the range of 0.5-1.0 mol / L to provide an appropriate amount of silicon source. If the concentration is too low, insufficient silicon replenishment will result in poor strengthening; if the concentration is too high, excessive silicon deposition may occur in the gel pores, clogging the channels and affecting the porosity and thermal insulation performance of the aerogel. The pH value of the alkaline silicon solution is maintained at 10-12. Within this pH range, the condensation reaction rate of silanol groups is moderate, and the dissolution and redeposition processes of the silicon framework can proceed in balance, effectively strengthening the gel while avoiding excessive dissolution or collapse of the gel structure due to excessive alkalinity. Maintaining the solution temperature at 25-30℃ (room temperature or slightly above room temperature) during the aging process helps maintain suitable reaction kinetics. At this temperature, the condensation rate of silanol groups and the deposition rate of silicon are stable and controllable, avoiding rapid changes in the gel structure or uneven strengthening that can occur with high temperatures, and also preventing excessively slow reaction rates and prolonged treatment time caused by low temperatures. Furthermore, replacing the alkaline silicon solution every 12 hours ensures the continued effectiveness of the aging process. During prolonged aging, the active silicon source in the solution is consumed, and reaction byproducts may accumulate, leading to a decrease in solution activity. Regularly replacing the alkaline silicon solution with fresh one continuously provides a sufficient source of active silicon and a stable alkaline environment, thus ensuring that the gel is fully and uniformly strengthened throughout the 48-hour immersion process.

[0040] S5. Drying Treatment: Place the aerogel-glass fiber composite gel after the aging treatment in step S4 into a microwave drying device and heat for 10 minutes. Then, transfer the heated gel-glass fiber composite gel to an oven and dry it at 80°C to obtain an aerogel insulation sheet. As a preferred embodiment, a low-temperature setting (100-200W) is selected during the heating treatment in the microwave drying device; the oven drying time is 2-4 hours, and ventilation is maintained inside the oven during the drying process. Specifically, setting the heating power of the microwave drying device within the range of 100-200W ensures that the aerogel-glass fiber composite gel receives adequate energy input during the initial drying stage. Microwave drying is a technology that utilizes microwave energy to cause rapid vibration of water molecules within the material, generating heat and thus achieving rapid drying. Heating power is a key parameter in microwave drying, directly affecting the drying rate and drying uniformity. Lower power (e.g., 100W) is suitable for heat-sensitive or large-sized gels to avoid excessive internal stress; higher power (e.g., 200W) can improve drying efficiency and shorten the initial drying time. This power range is designed to balance drying efficiency with gel structure protection, avoiding gel skeleton collapse due to excessive power or insufficient drying due to insufficient power. Based on this, the drying time is controlled at 2-4 hours in an 80°C oven. Oven drying is a subsequent deep drying process designed to thoroughly remove residual solvent from the gel and stabilize the aerogel structure. Shorter times (e.g., 2 hours) may be suitable for cases with low initial solvent content or good microwave pre-drying effects; longer times (e.g., 4 hours) ensure more thorough solvent removal, especially for thicker gels or cases with significant solvent residue. Precise control of drying time helps avoid under-drying or over-drying, thus preserving the aerogel's porous structure and thermal insulation properties. Simultaneously, ventilation is maintained within the oven during the drying process. Ventilation is crucial in oven drying, helping to promptly remove solvent vapors evaporated within the oven, maintaining low humidity, thereby accelerating the drying process and preventing solvent vapors from condensing on the gel surface. Maintaining ventilation within the oven can be achieved in various ways, such as using an oven with an exhaust fan or installing appropriate vents on the oven door to ensure airflow. Ventilation can promptly remove evaporated water vapor or organic solvent vapor, reducing the relative humidity inside the oven and thus maintaining the drying driving force, preventing "moisture backflow" from negatively impacting the drying effect. Simultaneously, ventilation helps to even out the temperature inside the oven, avoiding localized overheating or overhumidification, and further protecting the microstructure of the aerogel.

[0041] S6. Performance Testing: The thermal insulation performance of the dried aerogel insulation sheet is tested to evaluate its insulation effect. As a preferred implementation method, the thermal insulation performance test adopts the steady-state plate method, with a test temperature range of 25-200℃ and an ambient humidity of 40-60%RH; the insulation temperature of qualified products is ≥130℃. Specifically, the steady-state plate method is a standard method widely used in measuring the thermal conductivity of materials. Its basic principle is to apply a constant temperature difference across the sample, and after the heat flow reaches a steady state, measure the heat flow and temperature difference through the sample to calculate the thermal conductivity or insulation performance of the material. This method provides accurate and repeatable insulation performance data and is a reliable means of evaluating the efficiency of insulation materials. The test temperature range is set at 25-200℃ to simulate the typical operating temperature environment that aerogel insulation sheets may face in practical applications. 25℃ represents a normal temperature environment, while 200℃ covers medium- and high-temperature insulation requirements, such as in building insulation, electronic equipment heat dissipation, or industrial pipeline insulation. By conducting tests within this broad temperature range, the performance stability of the thermal insulation sheet under different temperature conditions can be comprehensively evaluated. The ambient humidity is controlled within the range of 40-60% RH (relative humidity) to ensure the accuracy and comparability of the test results. Humidity is one of the important environmental factors affecting the thermal insulation performance of porous materials, especially aerogel materials. In practical applications, fluctuations in ambient humidity may cause the material to absorb moisture, thus affecting its thermal conductivity. Therefore, testing under standard humidity conditions can eliminate the interference of humidity on the test results and more accurately reflect the inherent thermal insulation capacity of the material. A thermal insulation temperature ≥130℃ is used as the criterion for qualified products. This means that only when the aerogel thermal insulation sheet can effectively isolate the high temperature on the heat source side, ensuring that the temperature on the other side reaches at least 130℃, is it considered a product that meets the performance requirements. This indicator directly reflects the product's high-temperature thermal insulation capability and is a key parameter for measuring its suitability for high-temperature thermal insulation applications. Thus, through the above technical solution, a standardized and quantitative performance evaluation process has been introduced after the aerogel thermal insulation sheet is prepared. The steady-state flat plate method is used for thermal insulation performance testing, providing accurate and reliable data on thermal conductivity or insulation effect. Testing is conducted over a wide temperature range of 25-200℃ and in a controlled humidity environment of 40-60% RH, ensuring a comprehensive evaluation of the product's thermal insulation performance under various practical conditions and eliminating the interference of environmental factors on the test results. Furthermore, a clear criterion of a qualified product's insulation temperature ≥130℃ is established, allowing for accurate screening of the prepared aerogel insulation sheets and ensuring their stable performance to meet medium- and high-temperature insulation requirements. This significantly improves the product's quality control level and application reliability.

[0042] This invention also discloses an aerogel insulation sheet prepared according to the aforementioned method. The aerogel insulation sheet prepared by this method exhibits excellent thermal insulation performance, structural stability, and good mechanical strength, and can be widely used in building insulation, heat dissipation protection for electronic equipment, or thermal insulation of industrial pipelines.

[0043] This invention also discloses the application of the aforementioned aerogel insulation sheet in building insulation, heat dissipation protection of electronic equipment, or thermal insulation of industrial pipelines. Specifically, the application of the aerogel insulation sheet in building insulation refers to using it as an insulation layer for building structures (such as walls, roofs, and floors) to reduce heat transfer. In implementation, the aerogel insulation sheet can be integrated into composite insulation boards, used as an additional insulation layer for interior and exterior walls, or as a filling material for roofs or floors. Installation methods include adhesive fixing, mechanical anchoring, or lamination with other building materials. This application effectively improves the overall thermal insulation performance of buildings and reduces energy consumption. The application of the aerogel insulation sheet in heat dissipation protection of electronic equipment refers to using it to provide thermal isolation or auxiliary heat dissipation for heat-sensitive components inside electronic equipment. In specific implementation, the aerogel insulation sheet can be cut into specific shapes according to the internal structure and hotspot distribution of the electronic equipment, used as a thermal interface material to fill between the heating element and the heat sink, or used as a thermal barrier to isolate different temperature zones. Its thinness and flexibility allow it to fit within the compact internal space of electronic devices, providing effective thermal management. The application of aerogel insulation sheets in industrial pipeline insulation refers to wrapping or covering the outside of industrial pipelines with these sheets to reduce heat loss or absorption by the fluids inside the pipeline (such as high-temperature steam, low-temperature liquids, etc.). In practice, aerogel insulation sheets can be fabricated into prefabricated shells, flexible felts, or rolls, and directly wound or installed on the pipeline surface. Its excellent temperature resistance and chemical stability enable it to withstand harsh industrial environments and ensure the efficient operation of pipeline systems.

[0044] This embodiment will further illustrate the present invention in conjunction with specific implementation parameters, and its specific implementation process is as follows:

[0045] Example 1:

[0046] This embodiment 11 includes the following steps:

[0047] (1) Preparation of mixed liquid: Weigh 300g of trimethylethoxysilane, add 3g of titanium dioxide (particle size 70nm, purity 99.8%), and stir at 500r / min for 20min to obtain a uniformly dispersed mixed liquid.

[0048] (2) Preparation of composite sol: Take 100 mL of the mixed liquid obtained in step (1) and mix it with 200 mL of tetraethyl orthosilicate (solid content 25 wt%, pH value 5.5) in a volume percentage ratio of 1:2. Stir at a stirring speed of 500 r / min for 5 min to obtain a uniform and stable composite sol.

[0049] (3) Gel molding: The composite sol is uniformly coated onto the glass fiber substrate (silica glass fiber substrate, thickness 1.62mm) at a coating amount of 250g / m². After standing at room temperature for 15 min, the composite sol is completely gelled to obtain an aerogel-glass fiber composite gel.

[0050] (4) Aging treatment: The composite gel is placed in an alkaline silicon solution and soaked and aged at room temperature for 48 hours. The alkaline silicon solution is replaced every 12 hours.

[0051] (5) Drying treatment: The aged composite gel was placed in a microwave drying device and heated at a low temperature of 150W for 10 min; then the sample was transferred to an 80℃ oven and dried for 2 h to obtain an aerogel heat insulation sheet.

[0052] (6) Performance test: The thermal insulation performance of the aerogel insulation sheet was tested using the steady-state plate method. The test temperature range was 25-200℃ and the test environment humidity was 50% RH. At the same time, its bulk density and porosity were tested.

[0053] The product performance test results of the aerogel insulation sheet obtained in this embodiment are shown in Table 1.

[0054] <![CDATA[Core density (kg / m 3 )]]> 401.28 Cold surface temperature (°C) 249.55 Peak temperature difference (°C) 145.75

[0055] Table 1

[0056] Example 2:

[0057] This embodiment 2 includes the following steps:

[0058] (1) Preparation of mixed liquid: Weigh 300g of trimethylethoxysilane, add 15g of titanium dioxide (particle size 70nm, purity 99.8%), and stir at 500r / min for 20min to obtain a uniformly dispersed mixed liquid.

[0059] (2) Preparation of composite sol: Take 100 mL of the mixed liquid obtained in step (1) and mix it with 200 mL of tetraethyl orthosilicate (solid content 25 wt%, pH value 5.5) at a volume percentage ratio of 1:2. Stir at a stirring speed of 500 r / min for 5 min to obtain a uniform and stable composite sol.

[0060] (3) Gel molding: The composite sol is uniformly coated onto the glass fiber substrate (silica glass fiber substrate, thickness 1.62mm) at a coating amount of 250g / m². After standing at room temperature for 15 min, the composite sol is completely gelled to obtain an aerogel-glass fiber composite gel.

[0061] (4) Aging treatment: The composite gel is placed in an alkaline silicon solution and soaked and aged at room temperature for 48 hours. The alkaline silicon solution is replaced every 12 hours.

[0062] (5) Drying treatment: The aged composite gel was placed in a microwave drying device and heated at a low temperature of 150W for 10 min; then the sample was transferred to an 80℃ oven and dried for 2 h to obtain an aerogel heat insulation sheet.

[0063] (6) Performance test: The thermal insulation performance of the aerogel insulation sheet was tested using the steady-state plate method. The test temperature range was 25-200℃ and the test environment humidity was 50% RH. At the same time, its bulk density and porosity were tested.

[0064] The product performance test results of the aerogel insulation sheet obtained in this embodiment are shown in Table 2.

[0065] Core density (kg / m3) 435.32 Cold surface temperature (°C) 268 Peak temperature difference (°C) 135.55

[0066] Table 2

[0067] Example 3

[0068] This embodiment 3 includes the following steps:

[0069] (1) Preparation of mixed liquid: Weigh 300g of trimethylethoxysilane, add 30g of titanium dioxide (particle size 70nm, purity 99.8%), and stir at 500r / min for 20min to obtain a uniformly dispersed mixed liquid.

[0070] (2) Preparation of composite sol: Take 100 mL of the mixed liquid obtained in step (1) and mix it with 200 mL of tetraethyl orthosilicate (solid content 25 wt%, pH value 5.5) in a volume percentage ratio of 1:2. Stir at a stirring speed of 500 r / min for 5 min to obtain a uniform and stable composite sol.

[0071] (3) Gel molding: The composite sol is uniformly coated onto the glass fiber substrate (silica glass fiber substrate, thickness 1.62mm) at a coating amount of 250g / m². After standing at room temperature for 15min, the composite sol is completely gelled to obtain an aerogel-glass fiber composite gel.

[0072] (4) Aging treatment: The composite gel is placed in an alkaline silicon solution and soaked and aged at room temperature for 48 hours. The alkaline silicon solution is replaced every 12 hours.

[0073] (5) Drying treatment: The aged composite gel was placed in a microwave drying device and heated at a low temperature of 150W for 10 minutes; then the sample was transferred to an 80℃ oven and dried for 2 hours to obtain an aerogel heat insulation sheet.

[0074] (6) Performance test: The thermal insulation performance of the aerogel insulation sheet was tested using the steady-state plate method. The test temperature range was 25-200℃ and the test environment humidity was 50% RH. At the same time, its bulk density and porosity were tested.

[0075] The product performance test results of the aerogel insulation sheet obtained in this embodiment are shown in Table 3.

[0076] <![CDATA[Core density (kg / m 3 )]]> 457.8 Cold surface temperature (°C) 282.43 Peak temperature difference (°C) 120.22

[0077] Table 3

[0078] In summary, the aerogel insulation sheet prepared by the method of this invention exhibits excellent thermal insulation performance. This method is simple, low-cost, and environmentally friendly, making it suitable for large-scale industrial production. The prepared aerogel insulation sheet can be widely used in various fields such as construction, electronics, and industry, demonstrating significant practical application value and market prospects.

[0079] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0080] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing aerogel insulation sheets at room temperature and pressure, characterized in that, Includes the following steps: S1. Preparation of the mixed liquid: Take a set mass of trimethylethoxysilane, and add titanium dioxide at 1% of the mass of trimethylethoxysilane to the set mass of trimethylethoxysilane. Stir evenly to form a mixed liquid. S2. Preparation of composite sol: The mixed liquid obtained in step S1 is mixed with tetraethyl orthosilicate at a volume percentage ratio of 1:2 and stirred evenly to obtain composite sol. S3. Gel molding: The composite sol obtained in step S2 is uniformly coated onto the glass fiber substrate and left to stand at room temperature. After the composite sol has completely gelled, an aerogel-glass fiber composite gel body is obtained. S4. Aging treatment: The aerogel-glass fiber composite gel obtained in step S3 is placed in an alkaline silica solution and soaked for aging for 48 hours. S5. Drying treatment: Place the aerogel-glass fiber composite gel after the aging treatment in step S4 into a microwave drying device and heat for 10 minutes; then transfer the gel-glass fiber composite gel after heating to an oven and dry at 80°C to obtain an aerogel heat insulation sheet. S6. Performance Testing: Conduct thermal insulation performance tests on the dried aerogel insulation sheet to evaluate its thermal insulation effect.

2. The method for preparing aerogel insulation sheets at room temperature and pressure according to claim 1, characterized in that: In step S1, the stirring speed is 400-500 r / min and the stirring time is 15-25 min.

3. The method for preparing aerogel insulation sheets at room temperature and pressure according to claim 1, characterized in that: In step S1, the titanium dioxide has a particle size of 50-100 nm and a purity of ≥99.5%.

4. The method for preparing aerogel insulation sheets at room temperature and pressure according to claim 1, characterized in that: In step S2, the pH value of the tetraethyl orthosilicate is 5.5-6.0; the mixing speed is 400-500 r / min, and the mixing time is 20-30 min.

5. The method for preparing aerogel insulation sheets at room temperature and pressure according to claim 1, characterized in that: In step S3, the glass fiber substrate is silica glass fiber with a thickness of 1.5-1.7 mm and a surface density of 80-120 g / m²; the coating amount of the composite sol is 200-300 g / m², and the standing time at room temperature is 15-20 min.

6. The method for preparing aerogel insulation sheets at room temperature and pressure according to claim 1, characterized in that: In step S4, the alkaline silicon solution is a mixture of sodium silicate aqueous solution and sodium hydroxide aqueous solution, wherein the concentration of sodium silicate is 0.5-1.0 mol / L and the pH value of the alkaline silicon solution is 10-12; the solution temperature is maintained at 25-30℃ during the aging process, and the alkaline silicon solution is replaced every 12 hours.

7. The method for preparing aerogel insulation sheets at room temperature and pressure according to claim 1, characterized in that: In step S5, the heating power of the microwave drying device is 100-200W; the drying time in the oven is 2-4 hours, and ventilation is maintained inside the oven during the drying process.

8. The method for preparing aerogel insulation sheets at room temperature and pressure according to claim 1, characterized in that: In step S6, the thermal insulation performance test adopts the steady-state plate method, the test temperature range is 25-200℃, and the test environment humidity is 40-60%RH; the thermal insulation temperature of qualified products is ≥130℃.

9. The aerogel insulation sheet prepared by the method according to any one of claims 1-8.

10. The application of the aerogel insulation sheet according to claim 9 in building insulation, heat dissipation protection of electronic equipment, or thermal insulation of industrial pipelines.

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