aerogel complex

Abstract

This invention relates to an aerogel composite that maintains excellent thermal insulation properties even when subjected to compression deformation due to pressure applied by various causes when applied as a thermal insulation material to batteries, electronic devices, automobiles, industrial equipment, or structures.

Description

[Technical Field]

[0001] Mutual citation with related applications (etc.) This application claims priority rights under Korean Patent Application No. 10-2023-0083943 dated June 29, 2023, Korean Patent Application No. 10-2023-0097729 dated July 26, 2023, and U.S. Patent Applications No. 18 / 386,103 and No. 18 / 386,108 dated November 1, 2023, and all content disclosed in the relevant Korean patent applications is incorporated herein by reference.

[0002] This invention relates to aerogel composites and their applications as thermal insulation materials. [Background technology]

[0003] Aerogel is a highly porous material with a porosity of approximately 90.0% to 99.9% and a pore size in the range of 1 nm to 100 nm, resulting in a high specific surface area (≥500 m²). 2 Aerogel is a substance that possesses excellent properties such as being ultralight, ultra-thermal, and ultra-low dielectric. Therefore, in addition to research and development of aerogel materials, active research and application studies are being conducted on its use as a transparent thermal insulation material, an environmentally friendly high-temperature thermal insulation material, an ultra-low dielectric thin film for highly integrated devices, a catalyst and catalyst support, an electrode for supercapacitors, and an electrode material for seawater desalination.

[0004] The greatest advantages of aerogel are its super-insulation properties, exhibiting a thermal conductivity of less than 0.300 W / m·K, which is lower than conventional organic insulation materials such as expanded polystyrene, and its ability to overcome the fatal weaknesses of organic insulation materials: their vulnerability to fire and the generation of harmful gases during a fire.

[0005] Generally, aerogels are manufactured by producing a hydrogel from a silica precursor such as water glass or alkoxysilane (TEOS, TMOS, MTMS, etc.), and then removing the liquid component inside the hydrogel without destroying its microstructure.

[0006] In particular, hydrophobic silica aerogel blankets, which have hydrophobic silica aerogel formed on fibers, are functional thermal insulation materials that prevent corrosion due to moisture and are widely used in construction and industrial sites. They can also be useful as thermal insulation, heat retention, or fire-resistant materials for aircraft, ships, automobiles, batteries, and other applications. However, when such silica aerogel blankets are applied to the aforementioned applications, there is a problem in that the thermal insulation performance is significantly reduced due to a pressurized environment caused by continuous thermal expansion from adjacent equipment, or due to the collapse of the aerogel structure caused by significant pressure from the surroundings during the installation of the aerogel insulation material. [Overview of the project] [Problems that the invention aims to solve]

[0007] One objective of the present invention is to provide an aerogel composite that can maintain a constant level of thermal insulation without a significant decrease in performance, even when exposed to a pressurized environment.

[0008] However, the technical problems that this invention aims to solve are not limited to those mentioned above. Other problems not mentioned should be clearly understood by those with ordinary knowledge in this industry from the following description. [Means for solving the problem]

[0009] According to one embodiment of the present invention, an aerogel composite comprising a fibrous substrate and an aerogel containing one or more pores, wherein when a pressure of 3 bar, 9 bar, or 24 bar is applied horizontally (laterally) to the cross-section of the aerogel composite to compress it, the thermal transmittance after compression is 1.8 times or less compared to the thermal transmittance before compression, and the thermal transmittance of the aerogel composite before and after compression can satisfy the following equation 3.

[0010] [Formula 3] {(Thermal transmittance before and after compression (a)) - (Average thermal transmittance before and after compression (b))} = (Average thermal transmittance before and after compression (b)) × A

[0011] In the formula 3, the heat transfer coefficient (a) before and after compression means the heat transfer coefficient obtained after compressing the aerogel composite in the horizontal direction (lateral direction) with respect to the cross-section of the aerogel composite at 0 bar, 3 bar, 9 bar, or 24 bar. The average value (b) of the heat transfer coefficient before and after compression means the average value of the heat transfer coefficient of the uncompressed aerogel composite and the heat transfer coefficient obtained after compressing the aerogel composite in the horizontal direction (lateral direction) with compression values of 3 bar, 9 bar, and 24 bar. A is a rational number from -0.25 to +0.25.

[0012] When applying compressions of 3 bar, 9 bar, and 24 bar in the horizontal direction (lateral direction) with respect to the cross-section of the aerogel composite, the heat transfer coefficient after compression can be more than 1 times and less than or equal to 1.8 times that before compression.

[0013] When applying a compression of 3 bar in the horizontal direction (lateral direction) with respect to the cross-section of the aerogel composite, the heat transfer coefficient after compression can be less than or equal to 1.45 times that before compression.

[0014] When applying compressions of 3 bar, 9 bar, and 24 bar in the horizontal direction (lateral direction) with respect to the cross-section of the aerogel composite, the compression recovery rate represented by the following formula 1 can be 60% or more: [Formula 1] Compression recovery rate (%) = {(thickness of the cross-section of the aerogel composite after compression) / (thickness of the cross-section of the aerogel composite before compression)} × 100

[0015] The heat transfer coefficient obtained after compressing the aerogel composite in the horizontal direction (lateral direction) with pressures of 3 bar, 9 bar, and 24 bar can satisfy the following formula 4: [Formula 4] (heat transfer coefficient after compression (c) - average value of heat transfer coefficient after compression (d)) = (average value of heat transfer coefficient after compression (d)) × B

[0016] In equation 4 above, the thermal transmittance after compression (c) refers to the thermal transmittance obtained after compressing the aerogel composite with a pressure of 3 bar, 9 bar, or 24 bar in the horizontal direction (lateral direction) relative to the cross-section, and the average value of the thermal transmittance after compression (d) refers to the average value of the thermal transmittance obtained after compressing the aerogel composite by applying pressures of 3 bar, 9 bar, and 24 bar, respectively, in the horizontal direction (lateral direction) relative to the cross-section. The aforementioned B is a rational number between -0.25 and +0.25. For the aerogel composite, the rate of change (C) of the thermal transmittance after compression per unit applied pressure, expressed by the following equation 5, can be a rational number between -0.100 and +0.100: [Formula 5] C = (Heat transfer coefficient after compression at pressure x - Heat transfer coefficient after compression at pressure y) / (xy)

[0017] In equation 5 above, x and y are each independently one of the pressure values ​​(in bar) from 3 bar, 9 bar, and 24 bar, and are different pressure values ​​from each other.

[0018] The aerogel may contain pores with a pore diameter of 30 nm or less in an amount of 30% to 45% of the pore volume of the skeletal structure. The aerogel may also contain pores with a pore diameter of 0.1 nm to 30 nm in an amount of 30% to 45% of the pore volume of the skeletal structure.

[0019] The density of the aerogel composite is 0.05 to 0.50 g / cm³. 3 It is possible.

[0020] Another embodiment of the present invention relates to a thermal insulation member comprising an aerogel composite provided in the present invention.

[0021] The thermal insulation member may further include a support member located on at least one of the upper and lower surfaces of the aerogel composite. [Effects of the Invention]

[0022] The aerogel composite provided in this invention, when applied as an insulating material to batteries, electronic devices, automobiles, industrial equipment, or structures, maintains an excellent level of thermal insulation even when pressure is applied to the aerogel composite due to expansion of adjacent equipment or structures or other causes, resulting in compression deformation. Best Mode for Carrying Out the Invention

[0023] According to one embodiment of the present invention, an aerogel composite comprising a fibrous substrate and an aerogel having one or more pores, When the aerogel composite is compressed horizontally (laterally) at 3 bar, 9 bar, and 24 bar across its cross-section, the thermal transmittance after compression is 1.8 times or less compared to the thermal transmittance before compression. The aerogel composite having a thermal transmittance before and after compression that satisfies the following equation 3: [Formula 3] {(Thermal transmittance before and after compression (a)) - (Average thermal transmittance before and after compression (b))} = (Average thermal transmittance before and after compression (b)) × A

[0024] In Equation 3, the thermal transmittance before and after compression (a) refers to the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) at 0 bar, 3 bar, 9 bar, or 24 bar relative to the cross-section, and the average value of the thermal transmittance before and after compression (b) refers to the thermal transmittance of the unpressurized aerogel composite and the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) at compression values ​​of 3 bar, 9 bar, and 24 bar relative to the cross-section. The aforementioned A is a rational number between -0.25 and +0.25.

[0025] When the aerogel composite is compressed horizontally (laterally) at 3 bar, 9 bar, and 24 bar in the cross-section, the thermal transmittance after compression may be more than 1 and less than or equal to 1.8 times the thermal transmittance before compression.

[0026] When a compression of 3 bar is applied to the cross-section of the aerogel composite in the horizontal direction, the thermal transmittance after compression may be 1.45 times or less compared to the thermal transmittance before compression.

[0027] When compressions of 3 bar, 9 bar, and 24 bar are applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate expressed by the following formula 1 may be 60% or more: [Formula 1] Compression recovery rate (%) = {(thickness of the cross-section of the aerogel composite after compression) / (thickness of the cross-section of the aerogel composite before compression)} × 100

[0028] The thermal transmittance obtained after compressing the aerogel composite in the horizontal direction (lateral direction) with pressures of 3 bar, 9 bar, and 24 bar relative to its cross-section can satisfy the following equation 4: [Formula 4] (Compressed thermal transmittance (c) - Average thermal transmittance after compression (d)) = (Average thermal transmittance after compression (d)) × B

[0029] In equation 4 above, the thermal transmittance after compression (c) refers to the thermal transmittance obtained after compressing the aerogel composite with a pressure of 3 bar, 9 bar, or 24 bar in the horizontal direction (lateral direction) relative to the cross-section, and the average value of the thermal transmittance after compression (d) refers to the average value of the thermal transmittance obtained after compressing the aerogel composite by applying pressures of 3 bar, 9 bar, and 24 bar, respectively, in the horizontal direction (lateral direction) relative to the cross-section. The aforementioned B is a rational number between -0.25 and +0.25. For the aerogel composite, the rate of change (C) of the thermal transmittance after compression per unit applied pressure, expressed by the following equation 5, can be a rational number between -0.100 and +0.100: [Formula 5] C = (Heat transfer coefficient after compression at pressure x - Heat transfer coefficient after compression at pressure y) / (xy)

[0030] In equation 5 above, x and y are each independently one of the pressure values ​​(in bar) of 3 bar, 9 bar, or 24 bar, and are different pressure values ​​from each other.

[0031] The aerogel may contain pores with a pore diameter of 30 nm or less, accounting for 30% to 40% of the pore volume of the skeletal structure.

[0032] The density of the aerogel composite is 0.05 to 0.50 g / cm³. 3 It is possible.

[0033] Another embodiment of the present invention relates to a thermal insulation member comprising an aerogel composite provided in the present invention.

[0034] The thermal insulation member may further include a support member located on at least one of the upper and lower surfaces of the aerogel composite. [Modes for carrying out the invention]

[0035] The present invention will be described in more detail below to aid in understanding the invention. In this regard, terms and words used herein and in the claims should not be interpreted only in their ordinary or dictionary sense, but should be interpreted in a sense and concept that is consistent with the technical idea of ​​the present invention, based on the principle that inventors can appropriately define the concepts of terms in order to best describe their invention.

[0036] According to one embodiment of the present invention, the present invention relates to an aerogel composite comprising a fibrous substrate and an aerogel having one or more pores.

[0037] The aforementioned "aerogel" refers to a three-dimensional network structure in which multiple aerogel particles, each approximately 2 to 20 nm in size, are aggregated or bound together to form multiple open pores.

[0038] The aerogel may be an inorganic silica aerogel formed from a silicon alkoxide compound or water glass as a precursor. The aerogel may consist of silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof. The aerogel may have at least some of the SiO2 on the surface of the SiO2 network structure having a Si-O-SiO2(CH3), Si-O-SiO(CH3)2, or Si-O-Si(CH3)3 bond structure. The manufacturing process of the aerogel is described in detail below.

[0039] The aforementioned "aerogel particles" are individual solid units of particles that form an aerogel, and can be in the form of powder, beads, microparticles, granules, pellets, aggregates, fibers, flakes, etc., and their form can be spherical, hemispherical, circular, semicircular, polygonal, hexahedron, rod-shaped, polyhedron, amorphous, etc. The average particle size of the aerogel particles may be approximately 10 to 2,000 nm, 10 to 1,500 nm, or 10 to 1,000, but is not limited thereto. The average particle size may be measured by any means known to those skilled in the art, such as scanning electron microscopy, dynamic light scattering, optical microscopy, or size exclusion methods, but is not limited thereto.

[0040] The aerogel may have a skeletal structure that includes mesopores, but may also include micropores or macropores in addition to the mesopores. Here, "mesopores" are pores with an average pore diameter in the range of approximately 2 nm to approximately 50 nm, "macropores" are pores with an average pore diameter exceeding approximately 50 nm, and "micropores" are pores with an average pore diameter of less than approximately 2 nm. The aerogel may contain at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% mesopores of the pore volume of the skeletal structure. In one specific example, the aerogel may contain mesopores. In one specific example, the aerogel may contain both mesopores and micropores. The size of the pores can be measured by any means known to those skilled in the art, such as gas adsorption experiments, mercury infiltration, capillary flow porometry, or positron annihilation lifetime spectroscopy (PALS), but is not limited to these.

[0041] In aerogels, pores with a diameter of 30 nm or less are not destroyed or undergo only minimal destruction even when the aerogel is compressed under high pressure (for example, at pressures of 37 bar or less, 33 bar or less, or 30 bar or less). By ensuring that a certain proportion of pores with a diameter of 30 nm or less are included in the aerogel, the thermal transmittance of the aerogel composite can be maintained within a certain range even under a pressurized environment compared to before pressurization.

[0042] More specifically, the aerogel may contain pores with a pore diameter of 30 nm or less, preferably 0.1 nm to 30 nm, in amounts of 25% or more, 26% or more, 27% or more, 28% or more, 29% or more, 30% or more, or 31% or more of the pore volume of the skeletal structure, and may contain 50% or less, 49% or less, 48% or less, 47% or less, 46% or less, 45% or less, 44% or less, 43% or less, 41% or less, or 40% or less, preferably 25% to 45%, 25% to 40%, 30% to 45%, or 30% to 40%. The aerogel may contain pores with a pore diameter of 30 nm or less in amounts of 30% to 45% of the pore volume of the skeletal structure. The aerogel may contain pores with a pore diameter of 30 nm or less in amounts of 37.5% to 38.5% of the pore volume of the skeletal structure. The aerogel may contain pores with a pore diameter of 0.1 nm to 30 nm, accounting for 30% to 45% of the pore volume of the skeletal structure.

[0043] Furthermore, the aerogel may contain pores with a pore diameter exceeding 30 nm in amounts of 50% or more, 51% or more, 52% or more, 53% or more, 54% or more, 55% or more, 56% or more, 57% or more, 58% or more, 59% or more, or 60% or more of the pore volume of the skeletal structure, and may contain 75% or less, 74% or less, 73% or less, 72% or less, 71% or less, 70% or less, or 69% or less, preferably 55% or more and 75% or less, 60% or more and 75% or less, 55% or more and 70% or less, or 60% or more and 70% or less.

[0044] The porosity of the aerogel may be 80% or more, 85% or more, 88% or more, 89% or more, 90% or more, 91% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more, preferably 80% or more and 99.9% or less, but is not limited to these values.

[0045] The aerogel composite has a structure in which at least a portion of a plurality of aerogel particles are dispersed, preferably bound, on the surface of a fiber-containing substrate, and at the same time, at least a portion of the plurality of aerogel particles are dispersed, preferably located, in the spaces between the fibers dispersed within the substrate. Examples of the substrate may include discrete fibers, films, sheets, nets, fibers, porous materials, foams, nonwoven fabrics, or laminates of two or more layers thereof. Depending on the application, the surface may also have surface roughness or a patterned surface.

[0046] The aforementioned fiber base materials include polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate (e.g., rayon, nylon), cotton (e.g., Lycra® manufactured by DuPont), carbon (e.g., graphite), polyacrylonitrile (PAN), PAN oxide, non-carbonized heat-treated PAN (e.g., those made of SGL carbon), glass fiber materials (S-glass, 901 glass, 902 glass, 475 glass, E-glass, etc.), silica-based fibers, such as quartz (e.g., Quacara manufactured by Saint-Gobain). Artzel®, Q-Fiber® felt (manufactured by Johns Manville), Saffil® (manufactured by Safil), Durablanket® (manufactured by Uniflac), and other silica fibers, Duraback® (manufactured by Carborundum), polyaramid fibers such as Kevlar®, Nomex®, Sontera® (manufactured by DuPont), CONEX (manufactured by Teijin), and polyolefins such as Tyvek® (manufactured by DuPont). (manufactured by DSM), Dyneema (registered trademark) (manufactured by DSM), Spectra (registered trademark) (manufactured by Honeywell), other polypropylene fibers, e.g., Typar (registered trademark), Xavan (registered trademark) (both manufactured by DuPont), fluoropolymers, e.g., PTFE under the trademark name Teflon (registered trademark) (manufactured by DuPont), Gore-tex (registered trademark) (manufactured by WLGORE), silicon carbide fibers, e.g., NICALCON (manufactured by COI Ceramics), ceramic fibers, e.g., NEXTEL (manufactured by 3M), Aqua The materials may include lyl polymers, wool, silk, hemp, leather, suede fibers, PBO fibers, Zylon® (manufactured by Toyobo Co., Ltd.), liquid crystal materials such as VECTAN (manufactured by Hoechst), Cambrelle fibers (manufactured by DuPont), polyurethane, polyamide, wool fibers, boron, aluminum, iron, stainless steel fibers, or other thermoplastic resins such as PEEK, PES, PET, PEK, and PPS, but are not limited to those containing spaces or voids that facilitate the insertion of aerogel and can further improve thermal insulation performance.

[0047] The thickness of the fiber substrate can be, but is not limited to, 0.5 to 20 mm.

[0048] In the aerogel composite, the fiber substrate and the aerogel may be mixed from the upper surface to the lower surface, but are not limited to this.

[0049] Also, at least a part of the upper surface or the lower surface of the aerogel composite, preferably the surface, may have an overall flat shape. Here, the "flat shape" means that no concavities and convexities are formed by an intentional embossing or coating process. Forming the upper and lower surfaces of the aerogel composite flat can improve the ease of work when laminating a support member such as a sheet on the surfaces of the upper and lower surfaces later, and can increase the adhesion retention rate of the support member. Also, even when the aerogel composite itself is directly applied as a heat insulating member without a support member, it is preferable because the frictional force with the surface of adjacent devices can be reduced.

[0050] The aerogel composite has excellent elasticity, flexibility, and strength. Even when the aerogel composite is compressed and deformed under a pressurized environment, it has excellent elastic resilience, and its heat insulation property can be maintained at a high level.

[0051] The density of the aerogel composite can be, but is not limited to, 0.05 to 0.50 g / cm 3 , 0.05 to 0.35 g / cm 3 , 0.05 to 0.30 g / cm 3 , 0.10 to 0.30 g / cm 3 , or 0.15 to 0.30 g / cm 3 . The density of the aerogel composite can be 0.05 to 0.35 g / cm 3 . The density of the aerogel composite can be 0.10 to 0.30 g / cm 3 . The density of the aerogel composite can be 0.15 to 0.30 g / cm 3 . The density of the aerogel composite can be 0.200 to 0.205 g / cm 3 .

[0052] With respect to the cross-section of the aerogel composite, the bar in the horizontal direction (lateral direction) is 1 bar or more, 2 bar or more, 3 bar or more, 4 bar or more, 5 bar or more, 6 bar or more, 7 bar or more, 8 bar or more, 9 bar or more, 10 bar or more, 15 bar or more, 20 bar or more, 25 bar or more, 30 bar or more, 35 bar or more, or 40 bar or more, and 50 bar or less, 45 bar or less, 40 bar or less, 35 bar or less, 35 bar or less, 25 bar or less, 20 bar or less, 15 bar or less, 10 bar or less, or 9 bar or less. When applying pressure of 8 bar or less, 7 bar or less, 6 bar or less, 5 bar or less, 4 bar or less, 3 bar or less, or 2 bar or less, the compression recovery rate may be 45% or more, 50% or more, 55% or more, 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more.

[0053] The "compression recovery rate" refers to the percentage of the thickness of the cross-section of the aerogel composite after a predetermined time has elapsed since compression relative to the thickness of the cross-section of the aerogel composite before compression, as shown in Formula 1 below. Here, the predetermined time may be, but is not limited to, 1 second or more, 5 seconds or more, 10 seconds or more, 30 seconds or more, 1 minute or more, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 1 hour or more, 2 hours or more, 4 hours or more, 6 hours or more, 8 hours or more, 10 hours or more, 12 hours or more, 24 hours or more, 48 hours or more, or 96 hours or more.

[0054] [Formula 1] Compression recovery rate (%) = {(thickness of the cross-section of the aerogel composite after compression) / (thickness of the cross-section of the aerogel composite before compression)} × 100

[0055] The aforementioned "pressure" value refers to the pressure applied per unit area of ​​the aerogel composite when pressure is applied horizontally (laterally) to the cross-section of the aerogel composite using a press machine or the like. When pressure is applied horizontally (laterally) to the cross-section of the aerogel composite using a press machine including a cylinder, the aforementioned effective pressure value may mean the product of the cross-sectional area of ​​the cylinder and the set pressure value divided by the area of ​​the specimen, as shown in Equation 2 below. However, it is not limited to this and may be calculated differently depending on the equipment or the manufacturer.

[0056] [Formula 2] Actual pressure value = (radius of the cylinder inner diameter of the press equipment (cm) × radius of the cylinder inner diameter of the press equipment (cm) × 3.14 × set pressure value) / (area of ​​the test piece (cm) 2 ))

[0057] In the above equation 2, the unit of the radius of the cylinder's inner diameter may be, for example, cm, and the unit of the area of ​​the specimen may be, for example, cm 2 The set pressure value can be in bar or kgf, but is not limited to these. The duration for which pressure is applied to the aerogel composite is not particularly limited, but may be, for example, 1 second or more, 5 seconds or more, 10 seconds or more, 30 seconds or more, 1 minute or more, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 1 hour or more, or 2 hours or more, and 24 hours or less, 12 hours or less, 10 hours or less, 8 hours or less, 6 hours or less, 4 hours or less, 2 hours or less, 1 hour or less, 50 minutes or less, 40 minutes or less, 30 minutes or less, 20 minutes or less, 10 minutes or less, 5 minutes or less, 1 minute or less, 30 seconds or less, or 5 seconds or less.

[0058] Applying pressure to the aerogel composite in the lateral direction means applying pressure horizontally to the cross-section of the aerogel composite, and more specifically, it means applying pressure to the aerogel composite in the direction from the top surface to the bottom surface or from the bottom surface to the top surface, that is, in the thickness direction.

[0059] When a pressure of 3 bar or more is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate may be 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more.

[0060] When a pressure of 5 bar or more, 10 bar or more, 15 bar or more, 20 bar or more, 25 bar or more, 30 bar or more, or 35 bar or more is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate may be 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more.

[0061] The compression recovery rate when a pressure of 3 bar is applied horizontally (laterally) to the cross-section of the aerogel composite may be 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more, preferably 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more, more preferably 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more.

[0062] When a pressure of 9 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rates are 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more, and 98%. It may be 60% or more, or 99% or more, preferably 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more, more preferably 70% or more, 72% or more, 74% or more, 76% or more, or 78% or more.

[0063] When a pressure of 15 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate is 55% or more, 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more. It may be % or more, 98% or more, or 99% or more, preferably 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more, more preferably 70% or more, 72% or more, 74% or more, or 76% or more.

[0064] When a pressure of 24 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate is 55% or more, 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more. It may be % or more, 98% or more, or 99% or more, preferably 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more, more preferably 70% or more, 72% or more, 74% or more, or 76% or more.

[0065] When a pressure of 30 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate is 53% or more, 55% or more, 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more. It may be % or more, 98% or more, or 99% or more, preferably 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more, more preferably 68% or more, 70% or more, 72% or more, 74% or more, or 76% or more.

[0066] When a pressure of 33 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate is 53% or more, 55% or more, 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, 96% or more, 97% or more. It may be % or more, 98% or more, or 99% or more, preferably 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more, more preferably 68% or more, 70% or more, 72% or more, 74% or more, or 76% or more.

[0067] When a pressure of 37 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the compression recovery rate is 50% or more, 55% or more, 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, 92% or more, 94% or more, 95% or more, and 96% or more. It may be 97% or more, 98% or more, or 99% or more, preferably 55% or more, 60% or more, 62% or more, 64% or more, 66% or more, 68% or more, 70% or more, 72% or more, 74% or more, 76% or more, 78% or more, 80% or more, 82% or more, 84% or more, 86% or more, 88% or more, 90% or more, or 92% or more, more preferably 55% or more, 60% or more, or 62% or more.

[0068] The thickness of the aerogel composite before compression is 20 mm or less, 15 mm or less, 14 mm or less, 13 mm or less, 12 mm or less, 11 mm or less, 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less, and 0.5 mm or more, 1 mm or more, or 2 mm or more, and can be appropriately adjusted by adjusting the thickness of the substrate and the amount of aerogel sol impregnated into the substrate depending on the application of the aerogel composite.

[0069] With respect to the cross-section of the aerogel composite, the bar in the horizontal direction (lateral direction) is 1 bar or more, 2 bar or more, 3 bar or more, 4 bar or more, 5 bar or more, 6 bar or more, 7 bar or more, 8 bar or more, 9 bar or more, 10 bar or more, 15 bar or more, 20 bar or more, 25 bar or more, 30 bar or more, 35 bar or more, or 40 bar or more, and 50 bar or less, 45 bar or less, 40 bar or less, 35 bar or less, 35 bar or less, 30 bar or less, 20 bar or less, 15 bar or less, 10 bar or less, 9 bar or less, 8 bar or less, 7 bar or less, 6 bar or less, 5 bar When applying pressures of 4 bar or less, 3 bar or less, or 2 bar or less, the thermal transmittance after compression may be 3 times or less, 2.9 times or less, 2.8 times or less, 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less, and may be 1 time or more or more than 1 time.

[0070] The aforementioned "thermal transmittance" refers to the rate at which heat is transferred from one layer of air to another through a solid object, and is calculated as 1 m³ per unit time. 2The thermal conductivity of an object is the value obtained by dividing the thermal conductivity of an object by its thickness. The amount of heat transferred by an object is affected by its thermal conductivity and thickness; the greater the thermal conductivity and the thinner the thickness, the greater the amount of heat transferred. Therefore, to have excellent thermal insulation performance, the thermal conductivity should be low and the thickness should be large. However, when pressure is applied to an elastic object such as an aerogel composite, the thermal conductivity and thickness may change after pressurization. In other words, unless it is a perfectly elastic material, the thickness can only decrease after pressurization, but if the thermal conductivity does not change, the decrease in thickness will increase the total amount of heat transferred. In other words, the thermal insulation performance can only decrease. Therefore, whether or not thermal insulation performance is maintained after pressurization cannot be confirmed simply by the thermal conductivity after pressurization alone, but can be confirmed by the thermal transmittance which takes into account both the thermal conductivity after pressurization and the thickness after pressurization. Even if the thermal conductivity decreases or is maintained after pressurization, if the thickness decreases significantly after pressurization, the thermal transmittance and total amount of heat transferred can only increase significantly.

[0071] Since the thermal conductivity and thickness of the aerogel composite do not change significantly even after pressurization, the rate of increase in thermal transmittance is not high compared to before pressurization, and the thermal insulation performance can be maintained at an excellent level without a significant decrease due to pressurization.

[0072] The aforementioned "thermal transmittance after compression" refers to the ratio of thermal conductivity to the thickness of the cross-section of the aerogel composite after a predetermined time has elapsed following compression by applying a specific level of pressure horizontally (laterally) to the cross-section of the aerogel composite. Here, the predetermined time may be, but is not limited to, 1 second or more, 5 seconds or more, 10 seconds or more, 30 seconds or more, 1 minute or more, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, 2 hours or more, 4 hours or more, 6 hours or more, 8 hours or more, 10 hours or more, 12 hours or more, 24 hours or more, 48 hours or more, or 96 hours or more.

[0073] The duration for which pressure is applied to the aerogel composite is not particularly limited, but may be, for example, 1 second or more, 5 seconds or more, 10 seconds or more, 30 seconds or more, 1 minute or more, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 1 hour or more, or 2 hours or more, and 24 hours or less, 12 hours or less, 10 hours or less, 8 hours or less, 6 hours or less, 4 hours or less, 2 hours or less, 1 hour or less, 50 minutes or less, 40 minutes or less, 30 minutes or less, 20 minutes or less, 10 minutes or less, 5 minutes or less, 1 minute or less, 30 seconds or less, or 5 seconds or less.

[0074] When a pressure of 3 bar or more, 5 bar or more, 10 bar or more, 15 bar or more, 20 bar or more, 25 bar or more, 30 bar or more, or 35 bar or more is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be 3 times or less, 2.9 times or less, 2.8 times or less, 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less compared to the thermal transmittance before compression.

[0075] When pressure is applied to the cross-section of the aerogel composite in the horizontal direction (lateral direction) at any one pressure value between 3 bar and 33 bar, the thermal transmittance after compression may be 2.0 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less compared to the thermal transmittance before compression.

[0076] When pressure is applied to the cross-section of the aerogel composite in the horizontal direction (lateral direction) at any one pressure value between 3 bar and 24 bar, the thermal transmittance after compression may be 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less compared to the thermal transmittance before compression.

[0077] When pressure is applied to the cross-section of the aerogel composite at any one of the pressure values ​​from 3 bar to 9 bar in the horizontal direction, the thermal transmittance after compression may be 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.45 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less compared to the thermal transmittance before compression.

[0078] When pressure is applied to the cross-section of the aerogel composite at any one pressure value between 9 bar and 33 bar in the horizontal direction, the thermal transmittance after compression may be 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less compared to the thermal transmittance before compression.

[0079] When pressure is applied to the cross-section of the aerogel composite at any one of the pressure values ​​from 15 bar to 33 bar in the horizontal direction, the thermal transmittance after compression may be 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, or 1.05 times or less compared to the thermal transmittance before compression.

[0080] When pressure is applied to the cross-section of the aerogel composite at any one of the pressure values ​​from 15 bar to 30 bar in the horizontal direction, the thermal transmittance after compression may be 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, or 1.05 times or less compared to the thermal transmittance before compression.

[0081] When pressure is applied to the cross-section of the aerogel composite at any one of the pressure values ​​from 24 bar to 33 bar in the horizontal direction (lateral direction), the thermal transmittance after compression may be 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less compared to the thermal transmittance before compression.

[0082] When pressure is applied to the cross-section of the aerogel composite at any one of the pressure values ​​from 24 bar to 30 bar in the horizontal direction (lateral direction), the thermal transmittance after compression may be 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less compared to the thermal transmittance before compression.

[0083] When pressure is applied to the cross-section of the aerogel composite at any one of the pressure values ​​from 30 bar to 33 bar in the horizontal direction (lateral direction), the thermal transmittance after compression may be 3 times or less, 2.9 times or less, 2.8 times or less, 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less compared to the thermal transmittance before compression.

[0084] When pressure is applied to the cross-section of the aerogel composite with a pressure value of 3 bar in the horizontal direction, the thermal transmittance after compression may be 1.45 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less compared to the thermal transmittance before compression, and preferably 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less.

[0085] When a compression of 3 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be 1.45 times or less than the thermal transmittance before compression. When a compression of 3 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be the same as the thermal transmittance before compression, or 1.45 times or less than the thermal transmittance before compression. When a compression of 3 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be greater than the thermal transmittance before compression, and 1.45 times or less than the thermal transmittance before compression.

[0086] When a pressure of 9 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be 1.85 or less, 1.8 or less, 1.7 or less, 1.6 or less, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, 1.05 or less, 1.04 or less, 1.03 or less, 1.02 or less, or 1.01 or less compared to the thermal transmittance before compression, and preferably 1.6 or less, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, or 1.1 or less, 1.05 or less, 1.04 or less, 1.03 or less, 1.02 or less, or 1.01 or less.

[0087] When a compression of 9 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be 1.85 times or less than the thermal transmittance before compression. When a compression of 9 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be the same as the thermal transmittance before compression, or 1.85 times or less than the thermal transmittance before compression. When a compression of 9 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be greater than the thermal transmittance before compression, and 1.85 times or less than the thermal transmittance before compression.

[0088] When a pressure of 15 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression is 2.35 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, and 1.03 times or less compared to the thermal transmittance before compression. It may be less than or equal to 1.02 times, or less than or equal to 1.01 times, preferably less than or equal to 2 times, 1.9 times, 1.8 times, 1.7 times, 1.6 times, 1.5 times, 1.4 times, 1.3 times, 1.2 times, 1.1 times, or less than or equal to 1.05 times, and more preferably less than or equal to 1.7 times, 1.6 times, 1.5 times, 1.4 times, 1.3 times, 1.2 times, or less than or equal to 1.1 times.

[0089] When a compression of 15 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be 2.35 times or less than the thermal transmittance before compression. When a compression of 15 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be the same as the thermal transmittance before compression, or 2.35 times or less than the thermal transmittance before compression. When a compression of 15 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be greater than the thermal transmittance before compression, and 2.35 times or less than the thermal transmittance before compression.

[0090] When a pressure of 24 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression is 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, 1.04 times or less, and 1.03 times. The following can be 1.02 times or less, or 1.01 times or less, preferably 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, or 1.05 times or less, and more preferably 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less.

[0091] When a compression of 24 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be 2.7 times or less than the thermal transmittance before compression. When a compression of 24 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be the same as the thermal transmittance before compression, or 2.7 times or less than the thermal transmittance before compression. When a compression of 24 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be greater than the thermal transmittance before compression, and 2.7 times or less than the thermal transmittance before compression.

[0092] When a pressure of 30 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression is 3 times or less, 2.9 times or less, 2.8 times or less, 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, and 1.0 It may be 4 times or less, 1.03 times or less, 1.02 times or less, or 1.01 times or less, preferably 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, or 1.05 times or less, more preferably 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less.

[0093] When a compression of 30 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be three times or less than the thermal transmittance before compression. When a compression of 30 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be the same as the thermal transmittance before compression, or three times or less than the thermal transmittance before compression. When a compression of 30 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be greater than the thermal transmittance before compression, and three times or less than the thermal transmittance before compression.

[0094] When a pressure of 33 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression is 3 times or less, 2.9 times or less, 2.8 times or less, 2.7 times or less, 2.6 times or less, 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less, 1.05 times or less, and 1.04 times. The following can be 1.03 times or less, 1.02 times or less, or 1.01 times or less, preferably 2.3 times or less, 2.2 times or less, 2.1 times or less, 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less, and more preferably 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, or 1.2 times or less.

[0095] When a compression of 33 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be three times or less than the thermal transmittance before compression. When a compression of 33 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be the same as the thermal transmittance before compression, or three times or less than the thermal transmittance before compression. When a compression of 33 bar is applied horizontally (laterally) to the cross-section of the aerogel composite, the thermal transmittance after compression may be greater than the thermal transmittance before compression, and three times or less than the thermal transmittance before compression.

[0096] When the aerogel composite is compressed by applying at least one of the following pressures in the lateral direction: 3 bar, 9 bar, and 24 bar, the thermal transmittance after compression may be the same as or 1.8 times or less the thermal transmittance before compression.

[0097] When the aerogel composite is compressed laterally by 3 bar, 9 bar, and 24 bar, the thermal transmittance after compression may be the same as or 1.8 times or less the thermal transmittance before compression.

[0098] When the aerogel composite is compressed laterally by 3 bar, 9 bar, and 24 bar, the thermal transmittance after compression may be greater than or 1.8 times the thermal transmittance before compression.

[0099] When the aerogel composite is compressed laterally by 3 bar, the thermal transmittance after compression is greater than or 1.1 times the thermal transmittance before compression; when compressed by 9 bar, the thermal transmittance after compression is 1.1 to 1.3 times the thermal transmittance before compression; and when compressed by 24 bar, the thermal transmittance after compression may be 1.25 to 1.35 times the thermal transmittance before compression, but is not limited to these cases.

[0100] As described above, when measuring the recovery rate and heat reflux rate after compression using press equipment, it is possible to prepare a single specimen from the aerogel composite and perform the measurements. However, if the width or length of the aerogel composite is smaller than the pressure-applying part of the measuring equipment, the measurement values ​​for the compression recovery rate and heat reflux rate can be considered substantially the same as those obtained from a single specimen, even if the aerogel composite is cut into two or more pieces and rearranged so that both the width and length are larger than the pressure-applying equipment.

[0101] The recovery rate after compression or the thermal transmittance after compression may have been measured on a rectangular aerogel composite specimen having dimensions of 20 cm × 20 cm. In this case, if the width or length of the fabricated aerogel composite is less than 20 cm, two or more specimens may be placed side by side, rearranged so that the size of each specimen is 20 cm × 20 cm, and then measured on such paper pieces.

[0102] The aerogel composite maintains an excellent level of thermal insulation performance without a significant decrease, because its thermal transmittance before and after compression remains within a specific range, regardless of the pressure (or compression) applied.

[0103] More specifically, the thermal transmittance obtained after compressing the aerogel composite with at least one pressure value between 0 and 24 bar satisfies the following equation 3: [Formula 3] {(Thermal transmittance before and after compression (a)) - (Average thermal transmittance before and after compression (b))} = (Average thermal transmittance before and after compression (b)) × A

[0104] In Equation 3, "thermal transmittance before and after compression (a)" means the thermal transmittance obtained after compressing the aerogel composite with at least one pressure value in the range of 0 to 24 bar in the horizontal direction (lateral direction) with respect to the cross-section of the aerogel composite. The thermal transmittance before and after compression (a) may mean the thermal transmittance obtained after compressing the aerogel composite by applying a pressure of 0 bar, 3 bar, 9 bar, or 24 bar. Here, a pressure of 0 bar means no pressurization (uncompressed), and therefore the thermal conductivity obtained after compressing with a pressure of 0 bar means the thermal transmittance of the aerogel composite without pressurization.

[0105] Furthermore, the "average value of thermal transmittance before and after compression (b)" refers to the average value of the thermal transmittance of the aerogel composite without pressurization (or compression) and the thermal transmittance obtained after compressing the aerogel composite with at least two pressure values ​​within the range of 0 bar to 24 bar in the horizontal direction (lateral direction) relative to the cross-section of the aerogel composite. It may also refer to the average value of the thermal transmittance obtained after applying pressure to the aerogel composite with at least two pressure values ​​from 0 bar, 3 bar, 9 bar, and 24 bar and compressing it.

[0106] The aforementioned A may be a rational number between -0.30 and +0.30, a rational number between -0.25 and +0.25, a rational number between -0.24 and +0.24, a rational number between -0.23 and +0.23, a rational number between -0.22 and +0.22, a rational number between -0.21 and +0.21, a rational number between -0.20 and +0.20, a rational number between -0.19 and +0.19, a rational number between -0.15 and +0.15, a rational number between -0.14 and +0.14, a rational number between -0.13 and +0.13, a rational number between -0.12 and +0.12, a rational number between -0.11 and +0.11, or a rational number between -0.10 and +0.10.

[0107] The thermal transmittance of an uncompressed (0 bar compressed) aerogel composite can satisfy equation 3 above. In this case, the average value of the thermal transmittance before and after compression (b) may represent the thermal transmittance of the uncompressed aerogel composite and the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at at least two pressure values ​​from 3 bar, 9 bar, and 24 bar.

[0108] The thermal transmittance obtained after compressing the aerogel composite at a pressure of 3 bar, 9 bar, or 24 bar may satisfy equation 3. In this case, the average value of the thermal transmittance before and after compression (b) may represent the thermal transmittance of the uncompressed (0 bar compressed) aerogel composite and the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at at least two pressure values ​​from 3 bar, 9 bar, and 24 bar.

[0109] The average value of the thermal transmittance before and after compression (b) refers to the average value of the thermal transmittance of the uncompressed (0 bar compressed) aerogel composite and the thermal transmittance obtained after compressing the aerogel composite by applying pressures of 3 bar, 9 bar, and 24 bar horizontally (laterally) to the cross-section of the aerogel composite, where A can be a rational number between -0.30 and +0.30, a rational number between -0.25 and +0.25, a rational number between -0.24 and +0.24, a rational number between -0.23 and +0.23, or -0.22 and +0.22.

[0110] The average value of the thermal transmittance before and after compression (b) refers to the average value of the thermal transmittance of the uncompressed (0 bar compressed) aerogel composite and the thermal transmittance obtained after compressing the aerogel composite by applying pressures of 3 bar and 9 bar in the horizontal direction (lateral direction) to the cross-section of the aerogel composite. In this case, A can be a rational number between -0.25 and +0.25, a rational number between -0.24 and +0.24, a rational number between -0.23 and +0.23, a rational number between -0.22 and +0.22, a rational number between -0.21 and +0.21, or a rational number between -0.20 and +0.20.

[0111] The thermal transmittance obtained after compressing the aerogel composite at a pressure of 0 bar, 3 bar, 9 bar, or 24 bar may satisfy equation 3. Here, the average value of the thermal transmittances before and after compression (b) refers to the thermal transmittance of the uncompressed (0 bar compressed) aerogel composite and the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at at least two pressure values ​​from 3 bar, 9 bar, and 24 bar. In this case, A may be a rational number between -0.25 and +0.25.

[0112] The thermal transmittance obtained after compressing the aerogel composite at pressures of 0 bar, 3 bar, 9 bar, and 24 bar, respectively, can satisfy Equation 3. Here, the average value of the thermal transmittance before and after compression (b) refers to the thermal transmittance of the uncompressed (0 bar compressed) aerogel composite and the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) at pressures of 3 bar, 9 bar, and 24 bar, respectively, with respect to the cross-section. In this case, the absolute value of A can be a rational number between 0.06 and 0.15.

[0113] The thermal transmittance obtained after compressing the aerogel composite at pressures of 0 bar (uncompressible) and 24 bar can satisfy equation 3. Here, the average value of the thermal transmittance before and after compression (b) refers to the thermal transmittance of the uncompressible (0 bar compressed) aerogel composite and the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) at pressures of 3 bar, 9 bar, and 24 bar, respectively, with respect to the cross-section. In this case, the absolute value of A can be a rational number between 0.10 and 0.15.

[0114] Furthermore, the aerogel composite maintains an excellent level of thermal insulation performance without a significant decrease, because its thermal transmittance after compression remains within a specific range regardless of the pressure (or compression) applied.

[0115] More specifically, the thermal transmittance obtained after compressing the aerogel composite with at least one pressure value between 3 and 30 bar satisfies the following equation 4: [Formula 4] (Compressed thermal transmittance (c) - Average thermal transmittance after compression (d)) = (Average thermal transmittance after compression (d)) × B

[0116] In Equation 4 above, "compressed thermal transmittance (c)" means the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at at least one pressure value in the range of 3 to 30 bar. The compressed thermal transmittance (c) may mean the thermal transmittance obtained after compressing with a pressure of 3 bar, 9 bar, 15 bar, 24 bar, or 30 bar. Alternatively, it may mean the thermal transmittance obtained after compressing with a pressure of 3 bar, 9 bar, or 24 bar. Alternatively, it may mean the thermal transmittance obtained after compressing with a pressure of 9 bar, 15 bar, 24 bar, or 30 bar.

[0117] Furthermore, the "average value of thermal transmittance after compression (d)" refers to the average value of thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at at least two pressure values ​​within the range of 3 bar to 30 bar. The average value of thermal transmittance after compression (d) may refer to the average value of thermal transmittance obtained after compressing with pressures of 3 bar, 9 bar, and 24 bar, respectively. Alternatively, it may refer to the average value of thermal transmittance obtained after compressing with pressures of 9 bar, 15 bar, 24 bar, and 30 bar, respectively.

[0118] The aforementioned B may be a rational number between -0.25 and +0.25, a rational number between -0.24 and +0.24, a rational number between -0.23 and +0.23, a rational number between -0.22 and +0.22, a rational number between -0.21 and +0.21, a rational number between -0.20 and +0.20, a rational number between -0.19 and +0.19, a rational number between -0.15 and +0.15, a rational number between -0.14 and +0.14, a rational number between -0.13 and +0.13, a rational number between -0.12 and +0.12, a rational number between -0.11 and +0.11, or a rational number between -0.10 and +0.10.

[0119] The thermal transmittance obtained after compressing the aerogel composite with a pressure of 9 bar, 15 bar, 24 bar, or 30 bar may satisfy equation 4. In this case, in equation 4, the thermal transmittance after compression (c) means the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with a pressure of 9 bar, 15 bar, 24 bar, or 30 bar relative to the cross-section, and the average value of the thermal transmittance after compression (d) may mean the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with a pressure of at least two of the pressure values ​​of 9 bar, 15 bar, 24 bar, and 30 bar relative to the cross-section.

[0120] The thermal transmittance obtained after compressing the aerogel composite at pressures of 9 bar, 15 bar, 24 bar, and 30 bar, respectively, can satisfy Equation 4. In this case, in equation 4, the thermal transmittance after compression (c) means the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at one of the pressure values ​​of 9 bar, 15 bar, 24 bar, and 30 bar, the average value of the thermal transmittance after compression (d) means the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at the respective pressure values ​​of 9 bar, 15 bar, 24 bar, and 30 bar, and B can be a rational number between -0.15 and +0.15, a rational number between -0.14 and +0.14, a rational number between -0.13 and +0.13, a rational number between -0.12 and +0.12, a rational number between -0.11 and +0.11, or a rational number between -0.10 and +0.10.

[0121] The thermal transmittance obtained after compressing the aerogel composite with a pressure of 3 bar, 9 bar, or 24 bar may satisfy equation 4. In this case, in equation 4, the thermal transmittance after compression (c) means the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with a pressure of 3 bar, 9 bar, or 24 bar relative to the cross-section, and the average value of the thermal transmittance after compression (d) may mean the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with at least two pressure values ​​from 3 bar, 9 bar, and 24 bar relative to the cross-section.

[0122] The thermal transmittance obtained after compressing the aerogel composite at pressures of 3 bar, 9 bar, and 24 bar can satisfy equation 4. In this case, in equation 4, the thermal transmittance after compression (c) means the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at one of the pressure values ​​of 3 bar, 9 bar, and 24 bar, the average value of the thermal transmittance after compression (d) means the average value of the thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at the respective pressure values ​​of 3 bar, 9 bar, and 24 bar, and B can be a rational number between -0.25 and +0.25, a rational number between -0.24 and +0.24, a rational number between -0.23 and +0.23, a rational number between -0.22 and +0.22, a rational number between -0.21 and +0.2, a rational number between -0.20 and +0.20, or a rational number between -0.19 and +0.19.

[0123] Furthermore, the rate of change (C) of the thermal transmittance after compression per unit applied pressure, expressed by the following formula 5 for the aerogel composite, can be a rational number of -0.10 or greater, -0.09 or greater, -0.08 or greater, -0.07 or greater, -0.06 or greater, -0.05 or greater, -0.04 or greater, -0.03 or greater, -0.02 or greater, or -0.01 or greater, and can also be a rational number of +0.10 or less, +0.09 or less, +0.08 or less, +0.07 or less, +0.06 or less, +0.05 or less, +0.04 or less, +0.03 or less, +0.02 or less, or +0.10 or less. Preferably, these may be rational numbers between -0.10 and +0.10, between -0.09 and +0.09, between -0.08 and +0.08, between -0.07 and +0.07, between -0.06 and +0.06, or between -0.05 and +0.05: [Formula 5] C = (Heat transfer coefficient after compression at pressure x - Heat transfer coefficient after compression at pressure y) / (xy)

[0124] In equation 5, x and y are each independent pressure values ​​(in bar) within the pressure range of 3 to 24 bar, and are different from each other.

[0125] In equation 5, x and y can each independently be any one of the pressure values ​​of 3 bar, 9 bar, 15 bar, and 24 bar.

[0126] In equation 5 above, x could be 24 bar and y could be 3 bar.

[0127] In equation 5 above, x could be 24 bar and y could be 9 bar.

[0128] In equation 5 above, x can be 15 bar and y can be 9 bar.

[0129] In equation 5 above, x could be 24 bar and y could be 15 bar.

[0130] The rate of change (C) of the thermal transmittance after compression per unit applied pressure can be a rational number between -0.10 and +0.10.

[0131] Furthermore, the aerogel composite may satisfy the following formula 6: [Formula 6] The thermal transmittance after compression (e) = the average thermal transmittance after compression (f) × D

[0132] In equation 6 above, "heat transfer coefficient after compression (e)" means the heat transfer coefficient obtained after compressing the aerogel composite by applying a pressure of 3 bar, 9 bar, 15 bar, 24 bar, or 30 bar in the horizontal direction (lateral direction) to the cross-section of the aerogel composite. The aforementioned "average value of thermal transmittance after compression (f)" refers to the average value of thermal transmittance obtained after compressing the aerogel composite horizontally (laterally) with respect to its cross-section at at least two pressure values ​​from among 3 bar, 9 bar, 15 bar, 24 bar, and 30 bar. The aforementioned D may be a rational number between 0.70 and 1.20, a rational number between 0.75 and 1.20, a rational number between 0.80 and 1.20, a rational number between 0.85 and 1.20, a rational number between 0.75 and 1.18, a rational number between 0.80 and 1.18, a rational number between 0.85 and 1.18, a rational number between 0.75 and 1.16, a rational number between 0.80 and 1.16, a rational number between 0.85 and 1.16, a rational number between 0.80 and 1.14, a rational number between 0.85 and 1.14, a rational number between 0.80 and 1.12, a rational number between 0.85 and 1.12, a rational number between 0.85 and 1.10, a rational number between 0.90 and 1.12, or a rational number between 0.85 and 1.10.

[0133] In equation 6, the thermal transmittance after compression (e) is the thermal transmittance obtained after compressing the aerogel composite with a pressure of 9 bar in the horizontal direction (lateral direction) relative to the cross-section, and the average value of the thermal transmittance after compression (f) is the average value of the thermal transmittance obtained after compressing with pressures of 9 bar, 15 bar, 24 bar, and 30 bar, respectively, in which case D can be a rational number between 0.85 and 1.12, a rational number between 0.90 and 1.12, a rational number between 0.85 and 1.10, a rational number between 0.90 and 1.10, a rational number between 0.85 and 1.0, or a rational number between 0.90 and 1.0.

[0134] In equation 6, the thermal transmittance after compression (e) is the thermal transmittance obtained after compressing the aerogel composite with a pressure of 30 bar in the horizontal direction (lateral direction) relative to the cross-section, and the average value of the thermal transmittance after compression (f) is the average value of the thermal transmittance obtained after compressing with pressures of 9 bar, 15 bar, 24 bar, and 30 bar, respectively, in which case D can be a rational number between 0.90 and 1.12, a rational number between 0.95 and 1.12, a rational number between 0.90 and 1.10, a rational number between 0.95 and 1.10, a rational number between 1.0 and 1.12, or a rational number between 1.0 and 1.10.

[0135] In equation 6, the thermal transmittance after compression (e) is the thermal transmittance obtained after compressing the aerogel composite with a pressure of 3 bar in the horizontal direction (lateral direction) relative to the cross-section, and the average value of the thermal transmittance after compression (f) is the average value of the thermal transmittance obtained after compressing with pressures of 3 bar, 9 bar, and 24 bar, respectively, in which case D can be a rational number between 0.75 and 1.20, a rational number between 0.75 and 1.18, a rational number between 0.75 and 1.16, a rational number between 0.75 and 1.14, a rational number between 0.80 and 1.14, a rational number between 0.75 and 1.20, a rational number between 0.80 and 1.12, a rational number between 0.75 and 1.10, a rational number between 0.80 and 1.10, a rational number between 0.75 and 1.05, or a rational number between 0.80 and 1.05.

[0136] In equation 6, the thermal transmittance after compression (e) is the thermal transmittance obtained after compressing the aerogel composite with a pressure of 24 bar in the horizontal direction (lateral direction) relative to the cross-section, and the average value of the thermal transmittance after compression (f) is the average value of the thermal transmittance obtained after compressing with pressures of 3 bar, 9 bar, and 24 bar, respectively, in which case D can be a rational number between 0.80 and 1.20, a rational number between 0.85 and 1.20, a rational number between 0.85 and 1.18, a rational number between 0.90 and 1.18, a rational number between 0.85 and 1.16, a rational number between 0.90 and 1.16, or a rational number between 0.95 and 1.16.

[0137] The aerogel composite may have a compressive strength at 10% deformation of 20kPa to 80kPa, 20kPa to 70kPa, 30kPa to 80kPa, 30kPa to 70kPa, 35kPa to 80kPa, or 35kPa to 70kPa, and may exhibit excellent mechanical strength. Here, the compressive strength may be measured by manufacturing a specimen in accordance with the ASTM C165 standard.

[0138] The aerogel composite has a tensile strength of 30 N / cm². 2 ~60N / cm 2 , 40 N / cm 2 ~55N / cm 2 , or 45 N / cm2 ~55N / cm 2 It may be such that it has excellent flexibility. Here, the tensile strength may be measured by manufacturing a specimen in accordance with the ASTM D638 standard.

[0139] In the present invention, the aerogel composite can generally be formed by the steps of producing a silica sol, impregnating a fibrous substrate with the silica sol and then gelling it, and drying it. Each step is described below. However, the specific manufacturing processes and examples thereof described herein are not intended to limit any particular type of aerogel or method for producing the same. This specification may include any aerogel formed by any relevant manufacturing method known to the ordinary art.

[0140] Steps for producing silica sol; In the present invention, a silica sol can be produced by mixing a silica precursor composition and a catalyst composition.

[0141] The silica precursor composition may contain water and / or a polar organic solvent in addition to the silica precursor.

[0142] The silica precursor can be any precursor usable to form a silica aerogel, but may be, for example, a silicon-containing alkoxide compound. More specifically, these may be tetraalkyl silicates such as tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetra-sec-butyl orthosilicate, tetra-tert-butyl orthosilicate, tetrahexyl orthosilicate, tetracyclohexyl orthosilicate, and tetradodecyl orthosilicate. More specifically, the silica precursor may be tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), or a mixture thereof.

[0143] Furthermore, the silica precursor may be a water glass solution. Here, the water glass solution may refer to a diluted solution obtained by adding distilled water to water glass and mixing it, and the water glass may be sodium silicate (Na2SiO3), which is an alkali silicate salt obtained by dissolving silicon dioxide (SiO2) and alkali.

[0144] Furthermore, the silica precursor may contain pre-hydrolyzed TEOS (HTEOS). HTEOS is an ethyl silicate oligomer with a broad molecular weight distribution, and its properties, such as gelation time, can be adjusted when synthesizing it from TEOS monomers into an oligomer, making it easily applicable to the user's reaction conditions. It also has the advantage of producing reproducible properties for the final product. HTEOS can generally be synthesized by a condensation reaction of TEOS that undergoes a partial hydration step under acidic conditions. In other words, HTEOS is an oligomer produced by condensing TEOS, and the oligomer may be partially hydrated.

[0145] The silica precursor composition may further contain a silicate containing a hydrophobic group. The silicate containing the hydrophobic group is not limited in type as long as it is an alkylsilane compound containing an alkyl group that induces hydrophobicity and a silane active group that can react with the -Si-O- active group of the wet gel. Specific examples include, but are not limited to, one or more selected from the group consisting of methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDEOS), ethyltriethoxysilane (ETES), and phenyltriethoxysilane (PTES).

[0146] If the silica precursor contains a silicate containing the hydrophobic group in the composition, it may be included with the tetraalkyl silicate in a molar ratio of 2:98 to 98:2 (molar ratio of silicate containing the hydrophobic group to tetraalkyl silicate). Within this range, it is possible to ensure the strength and thermal insulation performance of the aerogel with high efficiency while preventing shrinkage during drying at atmospheric pressure and thus preventing a decrease in thermal insulation performance.

[0147] The silica concentration of the silica precursor composition is 10 kg / m³. 3 ~100kg / m 3 , 20kg / m 3 ~80kg / m 3 , 30 kg / m3 ~70kg / m 3 , 30 kg / m 3 ~60kg / m 3 , or 35 kg / m 3 ~45kg / m 3 This is possible, but not limited to. The concentration of silica is the concentration of silica contained in the silica precursor relative to the silica precursor composition, and can be appropriately adjusted by varying the content of the silica precursor, organic solvent, and water.

[0148] The silica precursor may be used in an amount such that the silica content in the silica sol is 0.1% to 30% by weight, but is not limited to this. A silica content that satisfies the above range is preferable in that it ensures excellent mechanical properties of the aerogel composite, particularly flexibility, while also providing improved thermal insulation.

[0149] The polar organic solvent may include alcohols, specifically monohydric alcohols such as methanol, ethanol, isopropanol, and butanol; polyhydric alcohols such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and sorbitol; or combinations thereof, but other solvents known to the ordinary art may also be used without limitation. Among these, the polar organic solvent may be a monohydric alcohol having 1 to 6 carbon atoms, such as methanol, ethanol, isopropanol, and butanol, considering its miscibility with water and aerogel, for example, ethanol.

[0150] The aforementioned polar organic solvent promotes the surface modification reaction and can be used in appropriate amounts by a typical technician, taking into account the degree of hydrophobicity of the final aerogel composite.

[0151] When producing the silica precursor described above, if the silica precursor is produced by electrohydrolysis, it can be produced by mixing the silica precursor and the organic solvent in a weight ratio of 1:0.1 to 1.5, 1:0.5 to 1.5, or 1:0.5 to 1.2, but is not limited to this.

[0152] When producing the aforementioned silica precursor, the silica precursor may be produced by electrohydrolysis by mixing the silica precursor and water in molar ratios of 1:0.1 to 10, 1:1 to 8, or 1:2 to 6, but is not limited to these.

[0153] Furthermore, when the silica precursor is produced, the silica precursor may be electrolyzed TEOS, but is not limited to, being produced by mixing the electrolyzed TEOS and an organic solvent in a weight ratio of 1:2 to 10, 1:3 to 8, or 1:3 to 6.

[0154] The silica precursor composition may further contain an acid catalyst, more specifically, when an alkoxysilane compound is used as the precursor instead of a hydrolysate, the acid catalyst may further be included. In this case, any acid catalyst that lowers the pH to 3 or less can be used without restriction, and any of these may be hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, or acetic acid. In this case, the acid catalyst may be added in an amount that lowers the pH of the sol to 3 or less, and may be added in the form of an aqueous solution dissolved in water.

[0155] The catalyst composition may contain an inorganic base such as sodium hydroxide or potassium hydroxide as a base catalyst; or an organic base such as ammonium hydroxide. Specific examples include, but are not limited to, sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), ammonia (NH3), ammonium hydroxide (NH4OH; aqueous ammonia), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), methylamine, ethylamine, isopropylamine, monoisopropylamine, diethylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, choline, monoethanolamine, diethanolamine, 2-aminoethanol, 2-(ethylamino)ethanol, 2-(methylamino)ethanol, N-methyldiethanolamine, dimethylaminoethanol, diethylaminoethanol, nitrilotriethanol, 2-(2-aminoethoxy)ethanol, 1-amino-2-propanol, triethanolamine, monopropanolamine, dibutanolamine, pyridine, or combinations thereof.

[0156] The base catalyst may be included in an amount such that the pH of the sol is between 5 and 9. If the pH of the sol deviates from this range, gelation may not be easy, or the gelation rate may become excessively slow, potentially reducing process efficiency. Furthermore, since the base may precipitate if added in solid form, it may be preferable to add it in a diluted solution with an aqueous solvent or the aforementioned organic solvent. In this case, the dilution ratio of the base catalyst and the organic solvent, specifically the alcohol, may be 1:4 to 1:100 based on volume, but is not limited to this.

[0157] The catalyst composition further contains an alkoxysilane compound having a hydrophobic group, which allows such a hydrophobic agent to react with the silica-wet gel to strengthen the structure and perform surface modification.

[0158] The alkoxysilane compound having the hydrophobic group is not limited to any alkylsilane compound containing an alkyl group that induces hydrophobicity and a silane active group that can react with the -Si-O- active group of the wet gel. Specific examples include, but are not limited to, one or more selected from the group consisting of trimethylethoxysilane (TMES), trimethylsilanol (TMS), trimethylchlorosilane (TMCS), methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), dimethyldiethoxysilane (DMDEOS), ethyltriethoxysilane, and phenyltriethoxysilane.

[0159] The alkoxysilane compound having a hydrophobic group may be included in an amount of 3 to 15 parts by weight, 5 to 10 parts by weight, or 6 to 8 parts by weight based on 100 parts by weight of silica sol, but is not limited to these amounts.

[0160] However, if the catalyst composition contains an alkoxysilane compound having a hydrophobic group, it may contain water to promote the surface modification reaction. The catalyst composition may contain 3 to 8 equivalents, 4 to 8 equivalents, or 5 to 6 equivalents of water based on 1 equivalent of the hydrophobic agent.

[0161] To produce the silica sol, the silica precursor composition and the catalyst composition may be mixed in a volume ratio of 1:0.01 to 10.0, 1:0.01 to 5.0, or 1:0.01 to 2.0, but are not limited to these.

[0162] If necessary, additives may be added to the silica sol. In this case, any known additives that can be added when manufacturing aerogels may be used, but for example, opacifiers and flame retardants may be used as additives.

[0163] The aforementioned additive may be added in amounts of 0.1% to 10% by weight, 0.1% to 7% by weight, 0.5% to 7% by weight, or 0.5% to 5% by weight relative to the silica content of the aerogel, but is not limited to these amounts.

[0164] Step to gel silica sol In this invention, after impregnating a substrate with silica sol, the silica sol can be gelled.

[0165] The impregnation step is a step to allow the catalytic silica sol to penetrate into the internal voids of the substrate, and can be carried out by introducing the catalytic silica sol and the substrate into a reaction vessel, or by spraying the catalytic silica sol onto the substrate moving on a conveyor belt in a roll-to-roll process. At this time, the substrate may be lightly pressed to improve the bonding between the substrate and the silica sol and ensure sufficient impregnation. Next, the material may be pressurized to a constant thickness at a constant pressure to remove excess silica sol and reduce the drying time.

[0166] The temperature of the silica sol in the reaction vessel may be 1 to 40°C, 20 to 40°C, 25 to 40°C, 30 to 40°C, or 35 to 45°C. It is preferable that the temperature of the silica sol in the reaction vessel satisfies the above range, as this makes it easier to achieve an appropriate viscosity range for the catalyzed sol and allows the desired viscosity range to be achieved even with a relatively short residence time.

[0167] The catalystd silica sol can be impregnated into the substrate in a volume ratio of 0.1 to 10:1 (catalyzed silica sol:substrate), 0.1 to 1:1, 0.3 to 1:1, 0.5 to 1:1, or 0.7 to 1:1, but is not limited to these.

[0168] In the present invention, the silica sol impregnated in the substrate can be gelled sequentially at the same time as or after the silica sol impregnation step.

[0169] The substrate impregnated with the catalyzed sol can be gelled on a moving element such as a conveyor belt.

[0170] The aforementioned "gelation" may refer to a sol-gel reaction, and the aforementioned "sol-gel reaction" may refer to the formation of a network structure from a silicon-unit precursor material. Here, the network structure may refer to a planar network pattern structure in which a specific polygon consisting of one or more types of atomic arrangements is connected, or a structure that forms a three-dimensional skeletal structure by sharing vertices, angles, faces, etc., of a specific polyhedron.

[0171] The gelation may be carried out under ambient temperatures of 20 to 40°C, 20 to 30°C, 25 to 40°C, 30 to 40°C, or 35 to 40°C, and the gelation time may be, but is not limited to, 1 to 120 minutes, 1 to 100 minutes, 1 to 60 minutes, 5 to 60 minutes, 5 to 40 minutes, 10 to 40 minutes, 10 to 30 minutes, or 10 to 20 minutes.

[0172] Step to mature the gelled wet gel complex. If necessary, the process may further include a maturation step in which the wet gel composite obtained from the gelation process is left at an appropriate temperature to allow the chemical changes to take place completely. The maturation step can further strengthen the network structure formed by the gelation process and improve the mechanical stability of the aerogel composite.

[0173] The maturation step can be carried out by leaving the gelled wet gel composite at an appropriate temperature, or by adding a cross-linking-promoting compound.

[0174] Furthermore, during the maturation step, a solution of a base catalyst such as sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), triethylamine, or pyridine, diluted in an organic solvent to a concentration of 1 to 10%, may be added in the presence of the wet gel complex. In this case, the Si-O-Si bond is maximally induced within the aerogel, further strengthening the network structure of the silica gel and making it easier to maintain the porosity structure in the subsequent drying step. The organic solvent may be the alcohols mentioned above, but more specifically, it may include ethanol.

[0175] The aforementioned maturation step may be carried out by leaving the product at a temperature of 30°C to 80°C, 40°C to 80°C, or 50°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours to strengthen the porosity structure. Within this range, it is possible to prevent a decrease in productivity while preventing solvent loss due to evaporation and thus preventing an increase in production costs.

[0176] Furthermore, the aging step may involve primary aging at 30°C to 80°C for 0.1 to 5 hours to strengthen the porosity structure, followed by secondary aging at 30°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours in the presence of a solution of base catalyst diluted to 1 to 10% in an organic solvent.

[0177] Furthermore, during the aging step (or during the secondary aging if the process is carried out in two stages), a mixed solution of an alkoxysilane compound and an alcohol can be added to provide not only an unreacted sol but also an additional sol precursor source, thereby inducing additional gelation of the silica gel network structure and further strengthening the gel structure. In this case, the alkoxysilane compound may be present in an amount of 0.5 to 9.5 parts by weight, 1.0 to 9.5 parts by weight, or 1.5 to 9.5 parts by weight per 100 parts by weight of the total aging solution.

[0178] The aforementioned alkoxysilane compounds include tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetra-sec-butyl orthosilicate, tetra-tert-butyl orthosilicate, tetrahexyl orthosilicate, tetracyclohexyl orthosilicate, and tetradodecyl orthosilicate. It may contain one or more substances selected from the group consisting of orthosilicate, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), trimethylchlorosilane (TMCS), ethyltriethoxysilane (ETES), dimethyldiethoxysilane (DMDEOS), and phenyltriethoxysilane.

[0179] Furthermore, the alcohol may be, in more detail, a monohydric alcohol such as methanol, ethanol, isopropanol, or butanol; or a polyhydric alcohol such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, or sorbitol, preferably a monohydric alcohol having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, or butanol, for example, ethanol, but not limited to these.

[0180] The maturation step may be carried out in a separate reaction vessel after the gelled wet gel composite has been recovered, or it may be carried out inside the reaction vessel in which the gelling step was performed.

[0181] Steps to modify the surface of the matured wet gel composite. If necessary, the process may further include a surface modification step in which the surface of the wet gel composite obtained by gelation as described above or the surface of the matured wet gel composite is made hydrophobic in the presence of a surface modifier.

[0182] The surface modifier can be any compound that hydrophobizes the surface of the wet gel, but may include, for example, silane compounds, siloxane compounds, silanol compounds, silazane compounds, or combinations thereof. Specific examples include, for example, trimethylchlorosilane (TMCS), dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), vinyltrimethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, and Silane compounds including traethoxysilane, dimethyldichlorosilane, and 3-aminopropyltriethoxysilane; siloxane compounds including polydimethylsiloxane, polydiethylsiloxane, or octamethylcyclotetrasiloxane; silanol compounds including trimethylsilanol, triethylsilanol, triphenylsilanol, and t-butyldimethylsilanol; 1,2-diethyldisilazane, 1,1,2,2-tetramethyldisilazane, and 1,1,3,3-tetramethyldisilazane Silazane compounds including disilazane, 1,1,1,2,2,2-hexamethyldisilazane (HMDS), 1,1,2,2-tetraethyldisilazane, or 1,2-diisopropyldisilazane; or combinations thereof; however, these may be and may not be limited to these.

[0183] The surface modifier can be used in solution form diluted in an organic solvent. Here, the organic solvent may be an alcohol (organic solvent), in which case the surface modifier can be diluted to 1 to 15% by volume based on the volume of the total diluted solution.

[0184] Furthermore, the surface modifier may be added in an amount of 0.01 to 90% by volume relative to the wet gel composite in order to achieve a sufficient surface modification effect, but is not limited to this amount.

[0185] The surface modification step may be carried out at a temperature of 50 to 90°C or 50 to 80°C for 1 to 24 hours, but is not limited to this.

[0186] Drying step The process may include a drying step of drying the surface-modified wet gel composite to obtain an aerogel composite.

[0187] The aforementioned drying process removes only the solvent while maintaining the porous structure of the matured gel, and can be carried out by methods such as supercritical drying or atmospheric pressure drying.

[0188] The supercritical drying process is carried out using supercritical carbon dioxide. For example, after placing a matured wet gel composite into a supercritical drying reactor, a solvent replacement process is performed in which liquid CO2 is packed in to replace the alcohol solvent inside the wet gel with CO2. Then, the temperature is raised to 40 to 70°C at a constant heating rate, for example, 0.1°C / min to 1°C / min. After that, a pressure above the pressure at which carbon dioxide becomes supercritical, for example, 100 bar to 150 bar, is maintained, and the carbon dioxide can be maintained in a supercritical state for a certain period of time, specifically 20 minutes to 1 hour. Generally, carbon dioxide becomes supercritical at a temperature of 31°C and a pressure of 78.8 bar. After maintaining the constant temperature and pressure at which carbon dioxide becomes supercritical for 2 to 12 hours, more specifically 2 to 6 hours, the pressure can be gradually removed to complete the supercritical drying process and produce an aerogel composite, but this is not limited to this.

[0189] Furthermore, the atmospheric pressure drying process may be carried out by conventional methods such as hot air drying or IR drying at a temperature of 70 to 200°C and atmospheric pressure (1 ± 0.3 atm), but is not limited to these methods.

[0190] In addition to the steps described above, the process includes acidification of a basic metal oxide precursor (e.g., sodium silicate) in water for the production of the hydrogel. Salt byproducts can be removed from the silicate precursor by ion exchange and / or by subsequent washing of the formed gel with water. Removal of water from the pores of the gel can be carried out by exchange with a polar organic solvent, such as ethanol, methanol, or acetone. The liquid in the gel is then at least partially extracted using innovative processing and extraction techniques.

[0191] In addition to the steps described above, the process also includes reducing damaging capillary forces at the solvent / pore interface by chemically deforming the matrix material in a wet gel state through the conversion of surface hydroxyl groups to hydrophobic trimethylsilyl ether, thereby enabling liquid pivoting from the gel material at temperatures and pressures below the critical point of the solvent.

[0192] In addition to the process described above, the liquid (solvent) within the gel material may be frozen at a lower temperature, followed by a sublimation process to remove the solvent from the gel material. Such removal or drying of the solvent from the gel material is understood to be within the scope of this disclosure. Such removal largely preserves the structure of the gel and produces an aerogel with unique properties.

[0193] The aerogel composite provided in this invention can be usefully used as an insulating material, heat-insulating material, or non-combustible material in various industrial equipment such as piping and industrial furnaces, as well as in plant facilities for heating and cooling, and in aircraft, ships, automobiles, electronic equipment, batteries, and more.

[0194] Another embodiment of the present invention relates to a thermal insulation member comprising an aerogel composite provided in the present invention.

[0195] The thermal insulation member may include the aerogel composite described above and a support member located on at least one of the upper and lower surfaces of the aerogel composite.

[0196] Examples of the support members include film-like support members, sheet-like support members, foil-like support members, and porous support members.

[0197] The aforementioned film-like support member is made by forming a polymer raw material into a thin film, and examples include organic films such as PET and polyimide, and glass films (including metal-deposited films).

[0198] The aforementioned sheet-like support member is made by molding organic, inorganic, or metallic fibrous raw materials, and examples include paper, nonwoven fabric (including glass mat), organic fiber fabric, and glass cloth.

[0199] The aforementioned foil-like support member is made by forming a metal raw material into a thin film, and examples include aluminum foil and copper foil.

[0200] The porous support member has a porous structure made from organic, inorganic, or metal materials, and examples include porous organic materials (e.g., polyurethane foam), porous inorganic materials (e.g., zeolite sheets), and porous metal materials (e.g., porous metal sheets, porous aluminum sheets).

[0201] The thickness of the support member is not particularly limited and may be, for example, 0.1 to 100 μm or 1 to 50 μm.

[0202] In the present invention, the heat insulating material can also be used as a heat insulating material, heat insulating material, or non-combustible material in the construction, aerospace, automotive, battery, home appliance, semiconductor, and industrial equipment fields.

[0203] The present invention will be described in detail below with reference to the following examples. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples.

[0204] Examples [Example 1] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4, and adding ethanol in a weight ratio of 1:1 with the TEOS. To promote the hydrolysis of the silica precursor solution, acid was added to lower the pH of the silica precursor solution to 3 or less, and the mixture was stirred for more than 2 hours to produce a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:6 to the hydrated TEOS solution. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 10 mm) as a substrate to allow the catalytic sol to permeate the fiber, ensuring that the catalytic silica sol impregnated the fiber mat in a volume ratio of 1:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while moving at a constant speed on a conveyor belt. During this process, the ambient temperature on the conveyor belt was maintained at 35°C. Next, the gelled wet gel composite was aged by adding 109% by volume of a solution of 2.9% by weight of methyltriethoxysilane (MTES) diluted in 10% by weight ethanol as a maturation solution, based on the volume of the wet gel composite, and aged at 75°C for 1 hour. To the aged wet gel composite, 90% by volume of a hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added as a surface modifier, based on the volume of the wet gel composite, and surface modification was performed at 75°C for 4 hours. Next, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.177 g / cc.

[0205] [Example 2] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4, and adding ethanol in a weight ratio of 1:1 with the TEOS. To promote the hydrolysis of the silica precursor solution, acid was added to lower the pH of the silica precursor solution to 3 or less, and the mixture was stirred for more than 2 hours to produce a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:4 to the hydrated TEOS solution. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 10 mm) as a substrate to allow the catalytic sol to permeate the fiber, with the catalytic silica sol impregnating the fiber mat in a volume ratio of 0.7:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing at a constant speed on a conveyor belt. During this process, the ambient temperature on the conveyor belt was maintained at 40°C. Next, the gelled wet gel composite was aged by adding 109% by volume of a solution of 2.9% by weight of methyltriethoxysilane (MTES) diluted in 10% by weight ethanol as a maturation solution, based on the volume of the wet gel composite, and aged at 75°C for 1 hour. To the aged wet gel composite, 90% by volume of a hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added as a surface modifier, based on the volume of the wet gel composite, and surface modification was performed at 75°C for 4 hours. Next, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.187 g / cc.

[0206] [Example 3] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and TEOS in a molar ratio of 97:3. The silica precursor composition was mixed with water in a molar ratio of 1:10, and ethanol in a weight ratio of 1:2 with the silica precursor composition was added to prepare a silica sol. Hydrochloric acid was added to promote hydrolysis so that the pH of the silica sol was 3 or less. A catalytic silica sol was prepared by adding a base catalyst solution (10 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 5 mm) as a substrate to allow the catalytic sol to permeate the fiber, with the catalytic silica sol impregnating the fiber mat in a volume ratio of 0.5:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing on a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 35°C. Next, a solution of ammonia water diluted in ethanol (2.4% by weight) was added to the gelled wet gel composite at a volume of 109% relative to the volume of the wet gel composite, and the mixture was aged at 75°C for 1 hour. To the aged wet gel composite, a hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added as a surface modifier at a volume of 90% relative to the volume of the wet gel composite, and the surface was modified at 75°C for 4 hours. Next, supercritical drying was performed under conditions of CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.170 g / cc.

[0207] [Example 4] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and TEOS in a molar ratio of 97:3. The silica precursor composition was mixed with water in a molar ratio of 1:10, and ethanol in a weight ratio of 1:2 with the silica precursor composition was added to prepare a silica sol. Hydrochloric acid was added to promote hydrolysis so that the pH of the silica sol was 3 or less. A catalytic silica sol was prepared by adding a base catalyst solution (10 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 5 mm) as a base to allow the catalytic sol to permeate the fiber, with the catalytic silica sol impregnating the fiber mat in a volume ratio of 0.7:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing on a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 40°C. Next, a solution of ammonia water diluted in ethanol (2.4% by weight) was added to the gelled wet gel composite at a volume of 109% relative to the wet gel composite, and the mixture was aged at 75°C for 1 hour. To the aged wet gel composite, a hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added as a surface modifier at a volume of 90% relative to the wet gel composite, and the surface was modified at 75°C for 4 hours. Next, supercritical drying was performed under conditions of CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.190 g / cc.

[0208] [Example 5] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and TEOS in a molar ratio of 97:3. The silica precursor composition was mixed with water in a molar ratio of 1:10, and ethanol in a weight ratio of 1:2 with the silica precursor composition was added to prepare a silica sol. Hydrochloric acid was added to promote hydrolysis so that the pH of the silica sol was 3 or less. A catalytic silica sol was prepared by adding a base catalyst solution (10 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 5 mm) as a substrate to allow the catalytic sol to permeate the fiber, with the catalytic silica sol impregnating the fiber mat in a volume ratio of 0.7:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing on a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 40°C. Next, the gelled wet gel composite was aged with 109% by volume of a solution of 2.4% by weight trimethylethoxysilane (TMES) diluted in ethanol, based on the volume of the wet gel composite, and aged at 75°C for 1 hour. To the aged wet gel composite, 90% by volume of a hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added as a surface modifier based on the volume of the wet gel composite, and surface modification was performed at 75°C for 4 hours. Next, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.211 g / cc.

[0209] [Example 6] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and TEOS in a molar ratio of 97:3. The silica precursor composition was mixed with water in a molar ratio of 1:10, and ethanol in a weight ratio of 1:2 with the silica precursor composition was added to prepare a silica sol. Hydrochloric acid was added to promote hydrolysis so that the pH of the silica sol was 3 or less. A catalytic silica sol was prepared by adding a base catalyst solution (10 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 5 mm) as a substrate to allow the catalytic sol to permeate the fiber, ensuring that the catalytic silica sol impregnated the fiber mat in a 1:1 volume ratio (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing on a conveyor belt at a constant speed. During this time, the ambient temperature on the conveyor belt was maintained at 35°C. Next, the gelled wet gel composite was aged at 75°C for 1 hour with 109% by volume of a solution of 2.4% by weight of trimethylethoxysilane (TMES) diluted in ethanol as a maturation solution. After aging at 75°C for 1 hour, 90% by volume of a solution of hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added to the aged wet gel composite as a surface modifier, and surface modification was performed at 75°C for 4 hours. Next, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.206 g / cc.

[0210] [Example 7] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4, and adding ethanol in a weight ratio of 1:1 with the TEOS. To promote the hydrolysis of the silica precursor solution, acid was added to lower the pH of the silica precursor solution to 3 or less, and the mixture was stirred for more than 2 hours to produce a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:4 to the hydrated TEOS solution. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 3 mm) as a substrate to allow the catalytic sol to permeate the fiber, with the catalytic silica sol impregnating the fiber mat in a volume ratio of 0.7:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing on a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 35°C. After gelation was complete, the mixture was stabilized at room temperature (25°C) for 10 minutes, followed by primary aging in a 70°C oven for 50 minutes. Next, a mixture of ethanol and aqueous ammonia (98:2 volume ratio) was prepared and added to the gelled wet gel composite in an amount 1.6 times the volume of the silica sol, followed by secondary aging in a 70°C oven for 1 hour. To the aged wet gel composite, a solution of trimethylethoxysilane (TMES) diluted in ethanol (2 vol%) was added as a surface modifier, at a volume of 90% based on the volume of the wet gel composite, followed by surface modification at 75°C for 2 hours. Next, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.189 g / cc.

[0211] [Example 8] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4, and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, acid was added to lower the pH of the silica precursor solution to 3 or less, and the mixture was stirred for more than 2 hours to produce a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:6 with the hydrated TEOS solution. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 3 mm) as a base to allow the catalytic sol to permeate the fiber, with the catalytic silica sol impregnating the fiber mat in a volume ratio of 0.7:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing on a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 25°C. After gelation was complete, the mixture was stabilized at room temperature (25°C) for 10 minutes, followed by primary maturation in a 70°C oven for 50 minutes. Next, a solution of 2.9% by weight of methyltriethoxysilane (MTES) diluted in 10% by weight ethanol was prepared and added to the gelled wet gel composite at a volume of 109% based on the wet gel composite's volume. Secondary maturation was then performed in a 70°C oven for 1 hour. To the matured wet gel composite, a solution of trimethylethoxysilane (TMES) diluted in ethanol (2% by volume) was added at a volume of 90% based on the wet gel composite's volume, followed by surface modification at 75°C for 2 hours. Finally, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.192 g / cc.

[0212] [Example 9] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4, and adding ethanol in a weight ratio of 1:1 with the TEOS. To promote the hydrolysis of the silica precursor solution, acid was added to lower the pH of the silica precursor solution to 3 or less, and the mixture was stirred for more than 2 hours to produce a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:6 to the hydrated TEOS solution. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. 33.3 L of this catalytic sol was packed into an impregnation tank, and then passed through a fiber (glass fiber mat, 5 mm) as a substrate to allow the catalytic sol to permeate the fiber, with the catalytic silica sol impregnating the fiber mat in a volume ratio of 0.7:1 (catalyzed silica sol:fiber). The fiber, impregnated with the catalytic sol after passing through the impregnation tank, was gelled for approximately 10 minutes while passing on a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 35°C. After gelation was complete, the mixture was stabilized at room temperature (25°C) for 10 minutes, followed by primary aging in a 70°C oven for 50 minutes. Next, a solution of 2.9% by weight of methyltriethoxysilane (MTES) diluted in 10% by weight ethanol was prepared and added to the gelled wet gel complex at a rate of 109% based on the volume of the wet gel complex. Secondary aging was then performed in a 70°C oven for 1 hour. Finally, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel complex with a density of approximately 0.204 g / cc.

[0213] [Comparative Example 1] A silica precursor composition was prepared by adding pre-hydrolyzed TEOS (silica content: 20% by weight, HTEOS), ethanol, and distilled water in a weight ratio of 1:2:0.22 and mixing them. A catalyst composition was prepared by adding ethanol, NaOH (5% by weight aqueous solution), and trimethylethoxysilane (TMES) in a weight ratio of 1:0.3:1 and mixing them. The prepared silica precursor composition and catalyst composition were mixed in a volume ratio of 9:1 in a reactor to produce a catalytic silica sol. The catalytic sol was impregnated into a fiber (glass fiber mat, 10 mm) as a substrate by passing it through the fiber. The catalytic silica sol was impregnated into the glass fiber mat in a volume ratio of 1:1 (catalyzed silica sol:glass fiber mat) relative to the volume of the glass fiber mat, and gelled for about 10 minutes to produce a wet gel composite. The fiber impregnated with the catalytic sol after passing through the impregnation tank was left at room temperature for 24 hours to gel, mature, and modify the surface. Next, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.206 g / cc.

[0214] [Comparative Example 2] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4, and adding ethanol in a weight ratio of 1:1 with the TEOS. To promote the hydrolysis of the silica precursor solution, acid was added to lower the pH of the silica precursor solution to 3 or less, and the mixture was stirred for more than 2 hours to produce a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:4 to the hydrated TEOS solution. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. The catalytic sol was impregnated into a fiber (glass fiber mat, 10 mm) as a substrate, by passing the sol through it. The catalytic silica sol was impregnated into the glass fiber mat in a volume ratio of 0.3:1 (catalyzed silica sol:glass fiber mat) relative to the volume of the glass fiber mat. The fibers impregnated with the catalytic sol passed through the impregnation tank and were gelled for about 10 minutes while moving at a constant speed on a conveyor belt. During this process, the ambient temperature on the conveyor belt was maintained at 35°C. Next, the gelled wet gel composite was left to mature in a 70°C chamber for 24 hours. To the matured wet gel composite, 90% by volume of hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added as a surface modifier based on the volume of the wet gel composite, and then surface modification was performed at 75°C for 4 hours. Next, supercritical drying was performed under the conditions of CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.142 g / cc.

[0215] [Comparative Example 3] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4, and adding ethanol in a weight ratio of 1:1 with the TEOS. To promote the hydrolysis of the silica precursor solution, acid was added to lower the pH of the silica precursor solution to 3 or less, and the mixture was stirred for more than 2 hours to produce a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:4 to the hydrated TEOS solution. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. The catalytic sol was impregnated into a fiber (glass fiber mat, 3 mm) as a substrate by passing it through the fiber, with the catalytic silica sol impregnating the glass fiber mat in a volume ratio of 0.5:1 (catalyzed silica sol:glass fiber mat). The fiber impregnated with the catalytic sol passed through the impregnation tank and gelled at room temperature for about 10 minutes while passing on a conveyor belt at a constant speed. After gelation was complete, the mixture was stabilized at room temperature (25°C) for 10 minutes, followed by primary aging in a 70°C oven for 50 minutes. Next, a mixture of ethanol and aqueous ammonia (98:2 volume ratio) was prepared and added to the gelled wet gel composite in an amount 1.6 times the volume of the silica sol, followed by secondary aging in a 70°C oven for 1 hour. Finally, supercritical drying was performed under CO2 150 bar and 70°C to produce an aerogel composite with a density of approximately 0.168 g / cc.

[0216] [Experimental Example 1] Measurement of density and stomatal size distribution 1, density For each silica aerogel composite prepared in each example and comparative example, five 10cm x 10cm specimens were prepared. The weight of each specimen was measured, and the thickness of the specimens was measured using a NETZSCH HFM436. The density was calculated from the measured weight, thickness, and size, and the average density of the five specimens was determined as the final density. The results are shown in Table 1 below.

[0217] 2. Volume percentage of effective pores with a pore diameter of 30 nm or less (%) For each of the silica aerogel composites produced in each of the examples and comparative examples, the nitrogen adsorption / desorption amount at a partial pressure (0.11 < p / p0 < 1) was analyzed using ASAP 2010 equipment manufactured by Micrometrics, and the specific surface area, pore volume, and pore diameter were measured. The volume ratio of pores (effective pores) having a numerical range of pore diameters of 30 nm or less was calculated using the measured pore volume, and the results are shown in Table 1 below.

[0218]

Table 1

[0219] [Experimental Example 2] Measurement of recovery rate and thermal reflux rate of aerogel composite after compression. 1. Compression recovery rate Using the aerogel composites obtained in each of the examples and comparative examples, specimens having a size of 20 cm × 20 cm were prepared. At this time, if the horizontal or vertical length of the produced aerogel composite was less than 20 cm, two or more specimens were arranged adjacent to each other in parallel and rearranged so that the size of the specimen became 20 cm × 20 cm. Then, measurements may be performed on such a paper piece. Each of the prepared specimens was pressure-bonded for 10 minutes under each pressure condition using QM900A-15T press equipment manufactured by QMESYS. When 1 hour had elapsed after pressure-bonding and before pressure-bonding, the thickness of the aerogel composite was measured using HFM436 equipment manufactured by Netzsch, and the compression recovery rate was calculated according to Equation 1 below, and the results are shown in Table 2 below. However, the pressure values shown in Table 2 below are the values of the pressure applied per unit area of the specimen, and mean the value obtained by multiplying the cylinder area of the press equipment and the set pressure value and dividing by the area of the specimen as shown in Equation 2. The radius of the cylinder of the QM900A-15T press equipment used in this experiment was 6.25 cm, and the size of the cylinder was 12.5 cm.

[0220] [Equation 1] Compression recovery rate (%) = {(thickness of the cross-section of the aerogel composite after compression) / (thickness of the cross-section of the aerogel composite before compression)} × 100 [Equation 2] Actual pressure value = (radius of the cylinder inner diameter of the press equipment (cm) × radius of the cylinder inner diameter of the press equipment (cm) × 3.14 × set pressure value) / (area of ​​the test piece (cm) 2 ))

[0221] 2, heat reflux rate After conducting the experiment using the same method as described in 1. above, the thermal conductivity of the aerogel composite was measured using Netzsch HFM436 equipment before compression and one hour after compression was completed. The heat reflux coefficient was then calculated, and the rate of increase in the heat reflux coefficient compared to before compression was evaluated. The results are shown in Table 3 below.

[0222] Furthermore, in order to confirm the degree of change in the heat recirculation coefficient before and after compression, the average value (b) of the heat recirculation coefficient measured after compression at pressures of uncompressed (0 bar), 3 bar, 9 bar, and 24 bar was calculated. Then, as shown in Equation 3 below, the difference between the heat recirculation coefficient (a) measured after compression at each pressure of 0 bar, 3 bar, 9 bar, and 24 bar and these average values ​​(b), and the value A obtained by dividing this difference by the average value (b), were calculated, and the results are shown in Table 4.

[0223] [Formula 3] {(Thermal transmittance before and after compression (a)) - (Average thermal transmittance before and after compression (b))} = (Average thermal transmittance before and after compression (b)) × A

[0224] Furthermore, in order to confirm the degree of change in the heat recirculation coefficient after compression, the average value (d) of the heat recirculation coefficient measured after compression at pressures of 3 bar, 9 bar, and 24 bar was calculated. The difference between the heat recirculation coefficient (c) measured after compression at pressures of 3 bar, 9 bar, or 24 bar and the average value (d), and the value B obtained by dividing that difference by the average value (d) of the heat recirculation coefficient were calculated as shown in Equation 4 below, and the results are shown in Table 5.

[0225] [Formula 4] (Compressed thermal transmittance (c) - Average thermal transmittance after compression (d)) = (Average thermal transmittance after compression (d)) × B

[0226] The results shown in Tables 2 through 5 below are rounded to two decimal places.

[0227] [Table 2A]

[0228] [Table 2B]

[0229] [Table 2C]

[0230] [Table 2D]

[0231] [Table 3A]

[0232] [Table 3B]

[0233] [Table 3C]

[0234] [Table 3D]

[0235] [Table 4A]

[0236] [Table 4B]

[0237] Table 4C

[0238] Table 4D

[0239] Table 4E

[0240] Table 5A

[0241] Table 5B

[0242]

Table 5C

[0243] Table 5D

[0244] As can be seen from Tables 2 to 5 above, the aerogel composites of Examples 1 to 9 produced by the present invention were found to have a higher compression recovery rate compared to the aerogel composites of Comparative Examples 1 to 3. Furthermore, even after compression, the increase in the thermal transmittance of the aerogel composite was less than before compression. It was confirmed that even when compressed to various pressure values ​​from low to high during compression, the change in thermal transmittance was small, and the thermal insulation performance was maintained at an excellent level. From these results, it was confirmed that the aerogel composite of the present invention has excellent pore elasticity, flexibility, and strength, and exhibits excellent recovery even after high-pressure compression. This prevents a rapid decrease in thermal insulation performance due to pore destruction, especially the destruction of pores smaller than 30 nm in size, and thus the thermal insulation performance is maintained at an excellent level even after compression.

[0245] Although specific parts of the present invention have been described in detail, it is clear to those with ordinary skill in the art that such specific technologies are merely preferred examples and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the attached claims and their equivalents. [Industrial applicability]

[0246] This invention relates to an aerogel composite that can maintain an excellent level of thermal insulation without a significant decrease in thermal insulation even when compressed by external pressure, and to its application as a thermal insulation material. The thermal insulation material can also be applied to batteries, electronic devices, automobiles, work equipment, or structures.

Claims

1. an aerogel composite comprising a fibrous substrate and an aerogel having one or more pores, When the aerogel composite is compressed by applying pressures of 3 bar, 9 bar, and 24 bar in the transverse direction to its cross-section, the thermal transmittance after compression is 1.8 times or less than the thermal transmittance before compression. The aerogel composite having a thermal transmittance before and after compression that satisfies the following equation 3: [Formula 3] {(Thermal transmittance before and after compression (a)) - (Average thermal transmittance before and after compression (b))} = (Average thermal transmittance before and after compression (b)) × A In the above equation 3, the thermal transmittance before and after compression (a) is the thermal transmittance obtained after compressing the aerogel composite laterally at 0 bar, 3 bar, 9 bar, or 24 bar, and the average value of the thermal transmittance before and after compression (b) means the average value of the thermal transmittance obtained after compressing the aerogel composite laterally at the respective compression values ​​of 0 bar, 3 bar, 9 bar, and 24 bar. The aforementioned A is a rational number between -0.25 and +0.

25.

2. The aerogel composite according to claim 1, wherein when the aerogel composite is compressed laterally by 3 bar, 9 bar, and 24 bar, the thermal transmittance after compression is more than 1 and less than or equal to 1.8 times the thermal transmittance before compression.

3. The aerogel composite according to claim 1, wherein when a compression of 3 bar is applied laterally to the aerogel composite, the thermal transmittance after compression is 1.45 times or less compared to the thermal transmittance before compression.

4. The aerogel composite according to claim 1, wherein when compressions of 3 bar, 9 bar, and 24 bar are applied laterally to the aerogel composite, the compression recovery rate represented by the following formula 1 may be 60% or more: [Formula 1] Compression recovery rate (%) = {(thickness of the cross-section of the aerogel composite after compression) / (thickness of the cross-section of the aerogel composite before compression)} × 100

5. The aerogel composite according to claim 4, wherein when compressions of 3 bar, 9 bar, and 24 bar are applied laterally to the aerogel composite, the compression recovery rate represented by formula 1 is 60% or more and 99% or less.

6. The aerogel composite according to claim 1, wherein the thermal transmittance obtained after compressing the aerogel composite laterally at pressures of 3 bar, 9 bar, and 24 bar, respectively, satisfies formula 4: [Formula 4] (Compressed thermal transmittance (c) - Average thermal transmittance after compression (d)) = (Average thermal transmittance after compression (d)) × B In the above equation 4, the thermal transmittance after compression (c) refers to the thermal transmittance obtained after compressing the aerogel composite with a pressure of 3 bar, 9 bar, or 24 bar in the lateral direction, and the average value of the thermal transmittance after compression (d) refers to the average value of the thermal transmittance obtained after compressing the aerogel composite by applying pressures of 3 bar, 9 bar, and 24 bar, respectively, in the lateral direction. The aforementioned B is a rational number between -0.25 and +0.

25.

7. The aerogel composite according to claim 1, wherein the rate of change (C) of the thermal transmittance after compression per unit applied pressure, represented by the following formula 5, is a rational number between -0.10 and +0.10: [Formula 5] C = (Heat transfer coefficient after compression at pressure x - Heat transfer coefficient after compression at pressure y) / (x - y) In equation 5, x and y are each independently one of the pressure values ​​(in bar) among 3 bar, 9 bar, and 24 bar, and are different pressure values ​​from each other.

8. The aerogel composite according to claim 1, wherein the aerogel contains pores with a pore diameter of 30 nm or less in an amount of 30% to 45% of the pore volume of the skeletal structure.

9. The aerogel composite according to claim 8, wherein the aerogel contains pores with a pore diameter of 0.1 nm to 30 nm, accounting for 30% to 45% of the pore volume of the skeletal structure.

10. The aerogel composite according to claim 1, wherein the aerogel contains pores with a pore diameter of 30 nm or less at a rate of 37.5% to 38.5% of the pore volume of the skeletal structure.

11. The density of the aerogel composite is 0.05 g / cm³. ３ ~0.50g / cm ３ The aerogel composite according to claim 1.

12. The density of the aerogel composite is 0.200 g / cm³. ３ ~0.205g / cm ３ The aerogel composite according to claim 1.

13. The aerogel composite according to claim 1, wherein the aerogel is a silica aerogel.

14. The aerogel composite according to claim 1, wherein the thermal transmittance after compression was measured one hour after compression.

15. The aerogel composite according to claim 6, wherein the thermal transmittance after compression was measured one hour after compression.

16. The aerogel composite according to claim 1, wherein when the aerogel composite is compressed laterally by 3 bar, the thermal transmittance after compression is greater than or 1.1 times or less than the thermal transmittance before compression; when compressed by 9 bar, the thermal transmittance after compression is 1.1 to 1.3 times that of the thermal transmittance before compression; and when compressed by 24 bar, the thermal transmittance after compression is 1.25 to 1.35 times that of the thermal transmittance before compression.

17. A thermal insulation member comprising the aerogel composite described in any one of claims 1 to 16.

18. The thermal insulation member according to claim 17, further comprising a support member located on at least one of the upper and lower surfaces of the aerogel composite.

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