Aerogel composite

Abstract

Disclosed is an aerogel composite having excellent high-temperature thermal stability such that the degree of decomposition or loss of the aerogel component is low even when exposed to a high-temperature environment for an extended period of time, and having excellent thermal insulation properties little due to low weight change over time at high temperatures.

Description

Aerogel composites

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0058657, filed May 2, 2024, and U.S. Patent Application No. 18 / 987,296, filed December 19, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to an aerogel composite and its use as an insulating material.

[0004] Aerogels are ultraporous, high surface area (≥500 m) materials with a porosity of approximately 90.0% to 99.9% and pore sizes in the range of 1 nm to 100 nm. 2 / g) is a material with excellent ultra-lightness, ultra-insulation, and ultra-low dielectric properties. Accordingly, research is being actively conducted on the development of aerogel materials, as well as on applications such as transparent and environmentally friendly high-temperature insulators, ultra-low dielectric thin films for highly integrated devices, catalysts and catalyst carriers, electrodes for supercapacitors, and electrode materials for seawater desalination.

[0005] The biggest advantage of aerogel is its super-insulation, which exhibits a thermal conductivity of less than 0.300 W / m·K, which is lower than that of conventional organic insulating materials such as Styrofoam.

[0006] Typically, aerogels are manufactured by manufacturing hydrogels from silica precursors such as water glass and alkoxysilanes (TEOS, TMOS, MTMS, etc.) and removing the liquid component inside the hydrogel without destroying the microstructure.

[0007] In particular, a hydrophobic silica aerogel blanket formed with hydrophobic silica aerogel on fibers is a functional insulating material that prevents corrosion due to moisture, and is widely used in construction or industrial sites. In addition, it can be usefully used as an insulating material or heat-insulating material for aircraft, ships, automobiles, batteries, etc.

[0008] However, when aerogel blankets are used for the above-mentioned purposes, or especially when installed in high-temperature piping, the aerogel blankets are often exposed to high-temperature environments for long periods of time. In such cases, problems such as the collapse of the aerogel structure due to decomposition or loss of some components within the aerogel may occur. Such problems may also occur when aerogel blankets are applied to battery modules within automobiles. Therefore, from a safety perspective, it is required to have excellent thermal stability by ensuring that the degree of decomposition or loss of aerogel components is low even when exposed to high-temperature environments for long periods of time.

[0009] One object of the present invention is to provide an aerogel composite having excellent thermal stability even when exposed to a high-temperature environment for a long period of time.

[0010] However, the technical problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

[0011] According to one embodiment of the present invention, there is provided an aerogel composite comprising a fiber substrate including a plurality of discrete fibers and voids between the fibers; and a plurality of aerogel particles positioned on the fibers or in the voids between the fibers, the aerogel having a network structure including one or more pores, wherein the weight retention measured after heating the aerogel composite at a temperature of 350° C. for 60 minutes may be 96% or more.

[0012] The weight retention measured after heating the above aerogel composite at a temperature of 350°C for 5 minutes or 30 minutes can satisfy the following equation 2:

[0013] [Formula 2]

[0014] A(%) = {(Weight retention rate measured after heating for x minutes (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0015] In the above equation 2, the x is 5 minutes or 30 minutes, the weight retention rate (a) measured after heating for x minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for x minutes, relative to the weight of the aerogel composite before heating at 350°C, and the average value (b) of the weight retention rates after heating means the average value of the weight retention rates obtained after heating the aerogel composite at a temperature of 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0016] The above A may be a real number between -1.0 and +1.0, or a real number between -0.80 and +0.80.

[0017] The weight retention (a) of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes and 30 minutes, respectively, can satisfy the above equation 2.

[0018] The weight retention (a) of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes respectively can satisfy the above equation 2.

[0019] The weight retention rate measured after heating the above aerogel composite at a temperature of 350°C for 30 minutes may be 97% or more.

[0020] When the above aerogel composite is heated at a temperature of 350°C for 5 minutes and 60 minutes, the absolute value (B) of the change in weight retention of the aerogel composite per unit time can satisfy the following equation 3:

[0021] [Formula 3]

[0022] B = |{(Weight retention measured after heating for y minutes) - (Weight retention measured after heating for z minutes)} / (y - z)|

[0023] In the above Equation 3, the y is 5 minutes, z is 60 minutes, the weight retention measured after heating for y minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for y minutes, relative to the weight of the aerogel composite before heating, and the weight retention measured after heating for z minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for z minutes, relative to the weight of the aerogel composite before heating. In addition, the B is 1.0 X 10 -3 7.0 X 10 -2 It is a mistake.

[0024] The ratio of the total volume of the fibers per unit volume of the aerogel composite may be 2 to 12%, and the volume ratio of the voids between the aerogel including pores and the discrete fibers in the aerogel composite may be 88 to 98%.

[0025] The total volume ratio of the fibers per unit volume of the aerogel composite may be 5 to 10%, and the volume ratio of the voids between the aerogel including pores and the discrete fibers in the aerogel composite may be 90 to 95%.

[0026] The fiber substrate and the aerogel in the above aerogel composite may be included in a weight ratio of 1:0.4 to 2.

[0027] The above aerogel may be a silica aerogel.

[0028] The above aerogel may include at least one selected from the group consisting of silica, methylsilylated silica, dimethylsilylated silica, and trimethylsilylated silica.

[0029] The above aerogel composite may have a moisture impregnation rate (weight %) of 4 wt% or less for a specimen of 100 mm X 100 mm size represented by the following formula 4:

[0030] [Formula 4]

[0031] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0032] In the above equation 4, the weight of the specimen after impregnation means the weight of the aerogel composite specimen after being impregnated in distilled water at 21±2°C for 15 minutes.

[0033] The above aerogel composite may have a moisture impregnation rate (weight%) of 2 weight% or less for a specimen having a size of 10 mm X 10 mm represented by the above formula 4.

[0034] According to another embodiment of the present invention, there is provided an insulating member comprising an aerogel composite provided by the present invention.

[0035] The above insulating member may further include a support member positioned on at least one of the upper and lower surfaces of the aerogel composite.

[0036] The aerogel composite provided in the present invention has excellent high-temperature thermal stability, so that even when exposed to a high-temperature environment for a long time, the degree of decomposition or loss of the aerogel component is not great, and the amount of weight change over time at a high temperature is small, so that the insulation property can be maintained at an excellent level.

[0037] Figure 1 illustrates an example process of setting and extracting a segmentation area for analyzing the volume occupancy of fibers and the remaining portion within the aerogel composite using Dragonfly software after performing in-situ XRM analysis on the aerogel composite in Experimental Example 1.

[0038] Figure 2 illustrates an example process of segmenting fibers and the remaining portion excluding fibers within a segmented area according to contrast level using Dragonfly software in Experimental Example 1.

[0039] Figure 3 illustrates an example process of calculating the volume occupancy rate (volume ratio) of each region after dividing the fibers and the remaining portion excluding the fibers using Dragonfly software in Experimental Example 1.

[0040] According to one embodiment of the present invention, there is provided an aerogel composite comprising a fiber substrate comprising a plurality of discrete fibers and voids between the fibers; and a plurality of aerogel particles positioned on the fibers or in the voids between the fibers, the aerogel having a network structure including one or more pores.

[0041] The weight retention rate measured after heating the above aerogel composite at a temperature of 350 ℃ for 60 minutes is 96% or more,

[0042] The weight retention measured after heating the above aerogel composite at a temperature of 350°C for 5 minutes or 30 minutes can satisfy the following equation 2:

[0043] [Formula 2]

[0044] A(%) = {(Weight retention rate measured after heating for x minutes (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0045] In the above equation 2, the x is 5 minutes or 30 minutes, the weight retention rate (a) measured after heating for x minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for x minutes, relative to the weight of the aerogel composite before heating at 350°C, and the average value (b) of the weight retention rates after heating means the average value of the weight retention rates obtained after heating the aerogel composite at a temperature of 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0046] The above A may be a real number between -1.0 and +1.0, or a real number between -0.80 and +0.80.

[0047] The weight retention (a) of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes and 30 minutes, respectively, can satisfy the above equation 2.

[0048] The weight retention (a) of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes respectively can satisfy the above equation 2.

[0049] The weight retention rate measured after heating the above aerogel composite at a temperature of 350°C for 30 minutes may be 97% or more.

[0050] When the above aerogel composite is heated at a temperature of 350°C for 5 minutes and 60 minutes, the absolute value (B) of the change in weight retention of the aerogel composite per unit time can satisfy the following equation 3:

[0051] [Formula 3]

[0052] B = |{(Weight retention measured after heating for y minutes) - (Weight retention measured after heating for z minutes)} / (y - z)|

[0053] In the above Equation 3, the y is 5 minutes, z is 60 minutes, the weight retention measured after heating for y minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for y minutes, relative to the weight of the aerogel composite before heating, and the weight retention measured after heating for z minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for z minutes, relative to the weight of the aerogel composite before heating. In addition, the B is 1.0 X 10 -3 7.0 X 10 -2 It is a mistake.

[0054] The ratio of the total volume of the fibers per unit volume of the aerogel composite may be 2 to 12%, and the volume ratio of the voids between the aerogel including pores and the discrete fibers in the aerogel composite may be 88 to 98%.

[0055] The total volume ratio of the fibers per unit volume of the aerogel composite may be 5 to 10%, and the volume ratio of the voids between the aerogel including pores and the discrete fibers in the aerogel composite may be 90 to 95%.

[0056] The fiber substrate and the aerogel in the above aerogel composite may be included in a weight ratio of 1:0.4 to 2.

[0057] The above aerogel may be a silica aerogel.

[0058] The above aerogel may include at least one selected from the group consisting of silica, methylsilylated silica, dimethylsilylated silica, and trimethylsilylated silica.

[0059] The above aerogel composite may have a moisture impregnation rate (weight %) of 4 wt% or less for a specimen of 100 mm X 100 mm size represented by the following formula 4:

[0060] [Formula 4]

[0061] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0062] In the above equation 4, the weight of the specimen after impregnation means the weight of the aerogel composite specimen after being impregnated in distilled water at 21±2°C for 15 minutes.

[0063] The above aerogel composite may have a moisture impregnation rate (weight%) of 2 weight% or less for a specimen having a size of 10 mm X 10 mm represented by the above formula 4.

[0064] According to another embodiment of the present invention, there is provided an insulating member comprising an aerogel composite provided by the present invention.

[0065] The above insulating member may further include a support member positioned on at least one of the upper and lower surfaces of the aerogel composite.

[0066] According to another embodiment of the present invention, there is provided a battery module comprising a module case having an internal space, one or more battery cells positioned in the internal space, and an aerogel composite provided in the present invention.

[0067] According to another embodiment of the present invention, there is provided a battery pack including the above-described battery module.

[0068] Hereinafter, the present invention will be described in more detail to facilitate understanding. The terms and words used in this specification and claims should not be interpreted based on their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0069]

[0070] According to one embodiment of the present invention, there is provided an aerogel composite comprising a fiber substrate; and an aerogel including one or more pores.

[0071] The above "aerogel" includes a plurality of primary aerogel particles having a size of approximately 0 to 10 nm or more and 0 to 5 nm or less, and secondary aerogel particles formed by agglomeration or bonding of these primary aerogel particles, and a plurality of open pores are formed between the primary aerogel particles and between the secondary aerogel particles to form aggregates, thereby forming a three-dimensional network structure of the aerogel.

[0072] The aerogel may be an inorganic silica aerogel formed from a silicon alkoxide compound or water glass as a precursor. As an example, the aerogel may include at least one selected from the group consisting of silica, methylsilylated silica, dimethylsilylated silica, and trimethylsilylated silica. As another example, the aerogel may have at least a portion of the SiO2 on the surface and / or inside the pores of the SiO2 network having a bonding structure of Si-O-SiO2(CH3), Si-O-SiO(CH3)2, or Si-O-Si(CH3)3. A specific silica aerogel manufacturing process is described in detail below.

[0073] Aerogel particles may be positioned on the fiber substrate or in the gaps between adjacent fiber substrates, and preferably, aerogel particles may be positioned on the fiber substrate and in the gaps between adjacent fiber substrates. The "aerogel particles" are individual solid unit particles forming an aerogel, and may include both primary aerogel particles having a size of approximately 0 to 10 nm or more, or 0 to 5 nm or less, preferably about 1 nm, and secondary aerogel particles formed by agglomeration of these particles. However, most of the aerogels in the aerogel composite are secondary aerogel particles or aggregated and combined forms thereof, and a trace amount of primary aerogel particles that do not form secondary aerogel particles may be mixed in. The secondary aerogel particles may have an average particle size of, but is not limited to, approximately 5 to 2,000 nm, 5 to 1,000 nm, 5 to 500 nm, 5 to 100 nm, or 5 to 50 nm. The average particle size may be measured by any means known to those skilled in the art, such as, but not limited to, scanning electron microscopy, dynamic light scattering, optical microscopy, or a size exclusion method.

[0074] The aerogel may have a skeletal structure including mesopores, and may also include micropores or macropores in addition to the mesopores. Here, the "mesopores" are pores having an average pore diameter in a range of about 2 nm to about 50 nm, the "macropores" are pores having an average pore diameter in a range exceeding about 50 nm, and the "micropores" are pores having an average pore diameter in a range less than about 2 nm. The aerogel may include mesopores for 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% of the pore volume of the skeletal structure. In one specific example, the aerogel may include mesopores. In one specific example, the aerogel may include mesopores and micropores. The pore size may be measured by any means known to those skilled in the art, such as, but not limited to, gas adsorption experiments, mercury intrusion, capillary flow porometry, or positron annihilation lifetime spectroscopy (PALS).

[0075] The porosity of the above aerogel may be 80% or more, 85% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more, and preferably 80% or more and 99.9% or less, but is not limited thereto.

[0076] The above aerogel composite has a structure in which at least some of a plurality of aerogel particles are dispersed, preferably bonded, on the surface of a substrate including fibers, and at the same time, at least some of the plurality of aerogel particles are dispersed, preferably positioned, in the empty spaces between the fibers within the substrate. Examples of the substrate may include discrete fibers, films, sheets, nets, fibers, porous bodies, foams, non-woven fabrics, or laminates of two or more layers thereof. In addition, depending on the intended use, the surface may have surface roughness or may be patterned.

[0077] The above fiber substrate is selected from the group consisting of polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate (e.g., rayon, nylon), cotton (e.g., Lycra from DuPont), carbon (e.g., graphite), polyacrylonitrile (PAN), oxidized PAN, non-carbonized heat-treated PAN (e.g., from SGL Carbon), glass fiber-based materials (S-glass, 901 glass, 902 glass, 475 glass, E-glass, etc.), silica-based fibers such as quartz (e.g., Quartzel from Saint-Gobain), Q-felt (from Johns Manville), Saffil (from Saffil), Durablanket (from Unifrax) and other silica fibers, Duraback (from carborundum), polyaramid fibers such as Kevlar, Nomex, Sontera (all from DuPont), Conex (from Tyjin), polyolefins such as Tyvek (from DuPont), Dyneema (from DSM), Spectra (manufactured by Honeywell), other polypropylene fibers such as Typar, Xavan (both from DuPont), fluoropolymers such as PTFE under the Teflon brand name (manufactured by DuPont), Goretex (manufactured by WL GORE), silicon carbide fibers such as Nicalcon (manufactured by COI Ceramics), ceramic fibers such as Nextel (manufactured by 3M), ceramic paper, acrylic polymers, wool, silk, hemp, leather, suede fibers, PBO-Xylon fibers (manufactured by Teflon), liquid crystal materials such as Vectan (manufactured by Hoechst), Cambrel fibers (manufactured by DuPont), polyurethane, polyamide, wool fibers, basalt fibers, boron, aluminum, iron, stainless steel fibers, or other thermoplastic resins such as PEEK, PES, PET, PEK, PPS, but any fiber that can further improve the insulating performance by including a space or void into which the aerogel can be easily inserted may be used without limitation. As an example, the fiber base may include glass fibers.As another example, the fiber substrate may be made of, but is not limited to, glass fibers.

[0078] The thickness of the above fiber substrate may be, but is not limited to, 0.1 to 20 mm.

[0079] The above aerogel composite may have a rectangular shape and may have a fiber substrate and aerogel mixed from the top to the bottom, but is not limited thereto.

[0080] In addition, at least a portion of the upper or lower surface of the aerogel composite, preferably the entire surface, may have a flat shape. Here, the "flat shape" means that no irregularities are formed by intentional embossing or a coating process. Forming the upper and lower surfaces of the aerogel composite flat as described above can increase the ease of work when laminating a support member such as a sheet on the surfaces of the upper and lower surfaces in the future, and can increase the adhesion maintenance rate of the support member. In addition, even if the aerogel composite itself is directly applied as an insulating member without a support member, it is preferable because the friction with the surface of an adjacent device can be reduced.

[0081] The thickness of the aerogel composite may be from 0.05 to 20 mm, for example, from 0.1 to 15 mm, from 0.1 to 10 mm, or from 0.1 to 5 mm, but is not limited thereto.

[0082] The density of the above aerogel composite is 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 It may include, but is not limited to.

[0083] The aerogel composite provided in the present invention comprises aerogel and voids including pores in a specific volume ratio or more, excluding fibers, so that the aerogel forms a solid pore structure, and not only can secure excellent insulation properties by these voids and pores, but also, even when exposed to a high temperature of 350°C or higher for a long time, there is little change in the structure of the aerogel or voids, and the degree of hydrophobicity inside the voids and pores is high, so that the insulation properties are not deteriorated even in a high-temperature environment and are maintained at an excellent level.

[0084] Specifically, the volume ratio of the voids between the aerogel including pores and the discrete fibers, excluding the fibers per unit volume of the aerogel composite, may be comprised of 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, or 90% or more, and 98% or less, 97% or less, 96% or less, 95% or less, 94% or less, or 93% or less, and preferably 88 to 98%, or 90 to 95%.

[0085] The volume ratio of the fibers per unit volume of the aerogel composite may be comprised of 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, or 10% or more, and 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, or 10% or less, and preferably 2 to 12%, or 5 to 10%.

[0086] However, the unit volume of the aerogel composite here refers to the volume of the aerogel composite in the shape of a rectangular parallelepiped with a width X length of 1 cm X 1 cm. The unit volume of the aerogel composite refers to the volume of the aerogel composite in the shape of a rectangular parallelepiped with a width X length of 1 cm X 1 cm. At this time, the volume of the aerogel composite refers to the volume obtained by multiplying the width X length X thickness of the aerogel composite, assuming that any material is filled in the pores or voids between the discrete fibers in the aerogel up to the area not filled with the aerogel particles. The volume of the fibers per unit volume of the aerogel composite refers to the sum of the volumes occupied by the individual fibers included in the unit volume of the aerogel composite. The volume of the remaining area excluding the fibers per unit volume of the aerogel composite includes the volume of the voids between the aerogel including the pores and the discrete fibers. At this time, the volume of the pores and voids can be calculated assuming that any material is filled evenly in the pores and voids. The volume of the voids between the aerogel and the fibers, which include pores per unit volume of the aerogel composite, can be calculated by subtracting the volume of the fibers alone from the unit volume of the aerogel composite.

[0087] The volume ratio of the aerogel including voids and pores per unit volume of the aerogel composite described above may be obtained by randomly obtaining a total of five rectangular parallelepiped specimens each having a width X length of 1 cm X 1 cm and a height that is the thickness of the aerogel composite from the aerogel composite, and calculating the average value of the volume ratio of the aerogel including voids and pores per unit volume of the aerogel composite measured from each specimen. At this time, the five specimens may be obtained by positioning a position 10 cm apart from each corner of an aerogel composite manufactured in a rectangular shape (for example, a size of 60 cm X 12 cm, but is not limited thereto) in the exact center of the specimen, thereby obtaining four specimens, and positioning the exact center of the aerogel composite such that one specimen is also in the exact center of the specimen.

[0088] In addition, the volume ratio of the aerogel including voids and pores per unit volume of the aerogel composite described above can be measured by placing an aerogel composite specimen on a load cell of DEBEN, performing In situ XRM analysis using VERSA 520 equipment of ZEISS, and measuring the volume ratio of the fibers and the remaining portion excluding the fibers in the analysis area (segmentation) with Dragonfly software (version 2021.3). At this time, the size of the analysis area (width X length X height) is not particularly limited, and can be set and extracted below each size of the unit volume, and as an example, can be set and extracted so that width X length X height is approximately 1700μm X 1600μm X 500μm. However, the above method is described for reference as an example of a method for measuring the volume ratio of voids between the aerogel including pores per unit volume of the aerogel composite described herein and the fibers, and is not limited to the above method.

[0089] In addition, after heating the aerogel composite at a temperature of 200° C. for 1 hour, the volume ratio of the voids between the aerogel and the fibers, excluding the fibers per unit volume of the heat-treated aerogel composite, may be comprised of 83% or more, 84% or more, 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, and 98% or less, 97% or less, 96% or less, 95% or less, 94% or less, 93% or less, 92% or less, 91% or less, or 90% or less, and preferably 85 to 98%, 88 to 98%, or 90 to 95%.

[0090] In addition, after heating the aerogel composite at a temperature of 200° C. for 1 hour, the volume ratio of the fibers per unit volume of the heat-treated aerogel composite may be included as 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 11% or more, 12% or more, and 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, or 10% or less, and preferably 2 to 15%, 2 to 12%, or 5 to 10%.

[0091] After heating the above aerogel composite at a temperature of 200°C for 1 hour, the volume ratio of the voids between the aerogel including pores and the discrete fibers based on the unit volume of the aerogel composite may be 0.8 to 1.5 times, 0.8 to 1.3 times, 0.8 to 1.2 times, 0.9 to 1.2 times, or 0.9 to 1.1 times the volume ratio of the voids between the aerogel including pores and the discrete fibers based on the unit volume of the aerogel composite before heating.

[0092] In addition, the aerogel composite can exhibit excellent insulation effects at both room temperature and high temperature by including aerogel in an amount greater than a certain ratio compared to the fiber substrate.

[0093] Specifically, the aerogel composite may contain aerogel in an amount of 0.35 times or more, 0.4 times or more, or 0.45 times or more based on the weight of the fiber substrate, and for example, the fiber substrate and the aerogel may be contained in a weight ratio of 1:0.35 to 2, preferably 1:0.4 to 2, or 1:0.4 to 1, or 1:0.45 to 1.

[0094] The above aerogel composite can be maintained at an excellent level without significant deterioration in its insulating performance as the weight retention of the aerogel composite is high and maintained constant within a specific range even when exposed to a temperature of 350°C or higher for a long period of time, such as 1 hour or more.

[0095] In this specification, the “weight retention rate” is expressed as a percentage of the weight measured after heating the aerogel composite at a temperature of 350°C for a predetermined period of time compared to the weight of the aerogel composite before heating, as in Equation 1 below. Here, the predetermined time may be, for example, 1 minute or more, 5 minutes or more, 10 minutes or more, 20 minutes or more, 25 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, 70 minutes or more, 80 minutes or more, 90 minutes or more, 2 hours or more, 4 hours or more, or 6 hours or more, and 12 hours or less, 6 hours or less, 4 hours or less, 2 hours or less, 90 minutes or less, 80 minutes or less, 70 minutes or less, 60 minutes or less, 40 minutes or less, 30 minutes or less, 20 minutes or less, 10 minutes or less, or 5 minutes or less, and one example may be 5 to 30 minutes, and another example may be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes, but is not limited thereto.

[0096] [Formula 1]

[0097] Weight retention of aerogel composite after heating (wt%) = {(Weight of aerogel composite after heating) / (Weight of aerogel composite before heating)} X 100

[0098] The weight retention measured after heating the above aerogel composite at a temperature of 350°C for any one of a continuous period of time selected from 5 minutes to 30 minutes may satisfy the following equation 2:

[0099] [Formula 2]

[0100] A (%) = {(Weight retention rate measured after heating for x minutes (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0101] In the above formula 2, the "x minutes" means any one of a continuous duration of 5 minutes to 30 minutes. As an example, the x minutes may be, but is not limited to, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes.

[0102] In addition, the above “weight retention (a) measured after heating for x minutes” means the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350° C. for x minutes, relative to the weight of the aerogel composite before heating at 350° C. according to the above equation 1.

[0103] In addition, the above "average value of weight retention rates after heating (b)" means an average value of weight retention rates of the aerogel composite obtained after heating the aerogel composite at a temperature of 350°C for at least two consecutive hours selected from 5 minutes to 30 minutes. As an example, it may mean an average value of weight retention rates of the aerogel composite obtained after heating the aerogel composite at 350°C for at least two consecutive hours selected from 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes relative to the weight of the aerogel composite before heating.

[0104] The above A (%) is - 1.0 to + 1.0, - 0.95 to + 0.95, - 0.90 to + 0.90, - 0.85 to + 0.85, - 0.80 to + 0.80, - 0.75 to + 0.75, - 0.70 to + 0.70, - 0.65 to + 0.65, - 0.60 to + 0.60, - 0.55 to + 0.55, - 0.50 to + 0.50, - 0.45 to + 0.45, - 0.40 to + 0.40, - 0.35 to + 0.35, - 0.30 to + 0.30, - 0.25 to + 0.25, - 0.20 to + 0.20, - It can be a real number in the range of 0.15 to + 0.15, or - 0.10 to + 0.10.

[0105] As an example, the weight retention of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes may satisfy Equation 2. In this case, the average value (b) of the weight retentions after heating may mean the average value of the weight retentions of the aerogel composite obtained after heating the aerogel composite at 350°C for at least two times selected from among 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0106] As an example, the weight retention of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes or 30 minutes may satisfy the above equation 2. In this case, the average value (b) of the weight retentions after heating may mean the average value of the weight retentions of the aerogel composite obtained after heating the aerogel composite at 350°C for at least two times selected from among 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0107] As an example, the weight retention ratio of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes and 30 minutes, respectively, may satisfy Equation 2. In this case, the average value (b) of the weight retention ratios after heating may mean the average value of the weight retention ratios of the aerogel composite obtained after heating the aerogel composite at 350°C for at least two times selected from among 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0108] As an example, the weight retention rate of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes may satisfy the above equation 2. In this case, the average value (b) of the weight retention rates after heating may mean the average value of the weight retention rates of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the above A (%) may be a real number falling within the range of - 1.0 to + 1.0, - 0.95 to + 0.95, - 0.90 to + 0.90, - 0.85 to + 0.85, - 0.80 to + 0.80, - 0.75 to + 0.75, - 0.70 to + 0.70, - 0.65 to + 0.65, 0 to + 1.0, 0 to + 0.95, 0 to + 0.90, 0 to + 0.85, 0 to + 0.80, 0 to + 0.75, 0 to + 0.70, or 0 to + 0.65.

[0109] As an example, the weight retention rate of the aerogel composite measured after heating the aerogel composite at 350°C for 10 minutes may satisfy the above equation 2. In this case, the average value (b) of the weight retention rates after heating may mean the average value of the weight retention rates of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the above A (%) may be a real number falling within the range of - 0.80 to + 0.80, - 0.75 to + 0.75, - 0.70 to + 0.70, - 0.65 to + 0.65, - 0.60 to + 0.60, - 0.55 to + 0.55, - 0.50 to + 0.50, - 0.45 to + 0.45, 0 to + 0.80, 0 to + 0.75, 0 to + 0.70, 0 to + 0.65, 0 to + 0.60, 0 to + 0.55, 0 to + 0.50 or 0 to + 0.45.

[0110] As an example, the weight retention rate of the aerogel composite measured after heating the aerogel composite at 350°C for 15 minutes may satisfy the above equation 2. In this case, the average value (b) of the weight retention rates after heating may mean the average value of the weight retention rates of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the above A (%) may be a real number falling within the range of - 0.60 to + 0.60, - 0.55 to + 0.55, - 0.50 to + 0.50, - 0.45 to + 0.45, - 0.40 to + 0.40, - 0.35 to + 0.35, - 0.30 to + 0.30, - 0.25 to + 0.25, or - 0.20 to + 0.20.

[0111] As an example, the weight retention rate of the aerogel composite measured after heating the aerogel composite at 350°C for 20 minutes may satisfy the above equation 2. In this case, the average value (b) of the weight retention rates after heating may mean the average value of the weight retention rates of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the above A (%) may be a real number falling within the range of - 0.50 to + 0.50, - 0.45 to + 0.45, - 0.40 to + 0.40, - 0.35 to + 0.35, - 0.30 to + 0.30, - 0.25 to + 0.25, - 0.20 to + 0.20, - 0.15 to + 0.15, - 0.10 to + 0.10, - 0.50 to 0, - 0.45 to 0, - 0.40 to 0, - 0.35 to 0, - 0.30 to 0, - 0.25 to 0, - 0.20 to 0, - 0.15 to 0, or - 0.10 to 0.

[0112] As an example, the weight retention rate of the aerogel composite measured after heating the aerogel composite at 350°C for 25 minutes may satisfy the above equation 2. In this case, the average value (b) of the weight retention rates after heating may mean the average value of the weight retention rates of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the above A (%) may be a real number falling within the range of - 0.80 to + 0.80, - 0.75 to + 0.75, - 0.70 to + 0.70, - 0.65 to + 0.65, - 0.60 to + 0.60, - 0.55 to + 0.55, - 0.50 to + 0.50, - 0.80 to 0, - 0.75 to 0, - 0.70 to 0, - 0.65 to 0, - 0.60 to 0, - 0.55 to 0, or - 0.50 to 0.

[0113] As an example, the weight retention rate of the aerogel composite measured after heating the aerogel composite at 350°C for 30 minutes may satisfy the above equation 2. In this case, the average value (b) of the weight retention rates after heating may mean the average value of the weight retention rates of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the above A (%) may be a real number falling within the range of - 1.0 to + 1.0, - 0.95 to + 0.95, - 0.90 to + 0.90, - 0.85 to + 0.85, - 0.80 to + 0.80, - 0.75 to + 0.75, - 1.0 to 0, - 0.95 to 0, - 0.90 to 0, - 0.85 to 0, - 0.80 to 0, or - 0.75 to 0.

[0114] As an example, the weight retention of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes or 30 minutes, respectively, may satisfy Equation 2. At this time, the average value (b) of the weight retentions after heating may mean the average value of the weight retentions of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the A (%) may be a real number falling within the range of - 1.0 to + 1.0, - 0.95 to + 0.95, - 0.90 to + 0.90, - 0.85 to + 0.85, - 0.80 to + 0.80, or - 0.75 to + 0.75.

[0115] As an example, the weight retention of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes and 30 minutes, respectively, may satisfy Equation 2. At this time, the average value (b) of the weight retentions after heating may mean the average value of the weight retentions of the aerogel composite obtained after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. At this time, the A (%) may be a real number falling within the range of - 1.0 to + 1.0, - 0.95 to + 0.95, - 0.90 to + 0.90, - 0.85 to + 0.85, - 0.80 to + 0.80, or - 0.75 to + 0.75.

[0116] As an example, the weight retention of the aerogel composite measured after heating the aerogel composite at 350°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes may satisfy Equation 2. At this time, the average value (b) of the weight retentions after heating may mean the average value of the weight retentions of the aerogel composite obtained after heating the aerogel composite at 350°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. At this time, the A (%) may be a real number falling within the range of - 1.0 to + 1.0, - 0.95 to + 0.95, - 0.90 to + 0.90, - 0.85 to + 0.85, - 0.80 to + 0.80, or - 0.75 to + 0.75.

[0117] In addition, when the aerogel composite is heated to a temperature of 350°C, the absolute value (B) of the change in the weight retention rate of the aerogel composite per unit time can satisfy the following equation 3.

[0118] [Formula 3]

[0119] B = |{(Weight retention measured after heating for y minutes) - (Weight retention measured after heating for z minutes)} / (y - z)|

[0120] In the above equation 3, y and z are time values ​​independently selected from a continuous time period of 5 to 60 minutes, and are different values. In this case, the unit of time may be 'minute'.

[0121] In addition, the above “weight retention measured after heating for y minutes” and “weight retention measured after heating for z minutes” mean the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350° C. for y minutes or z minutes, relative to the weight of the aerogel composite before heating according to the above Equation 1.

[0122] Also, the above B is 1.0 X 10 -3 7.0 X 10 -2 , 1.5 X 10 -3 7.0 X 10 -2 , 1.0 X 10 -3 6.5 X 10 -2 , 1.5 X 10 -3 6.5 X 10 -2 , 1.0 X 10 -3 6.0 X 10 -2 , 1.5 X 10 -3 6.0 X 10 -2 , 2.0 X 10 -3 6.0 X 10 -2 , 2.5 X 10 -3 6.0 X 10 -2 , 3.0 X 10 -3 6.0 X 10 -2 , 3.5 X 10 -3 6.0 X 10 -2 , 4.0 X 10 -3 6.0 X 10 -2 , 1.0 X 10 -35.5 X 10 -2 , 1.5 X 10 -3 5.5 X 10 -2 , 2.0 X 10 -3 5.5 X 10 -2 , 2.5 X 10 -3 5.5 X 10 -2 , 3.0 X 10 -3 5.5 X 10 -2 , 3.5 X 10 -3 5.5 X 10 -2 , or 4.0 X 10 -3 5.5 X 10 -2 It may be a mistake that falls within the range of .

[0123] As an example, in the above equation 3, y may be 5 minutes and z may be 30 minutes; or y may be 30 minutes and z may be 5 minutes. In this case, B may be 3.0 X 10 -3 7.0 X 10 -2 , 3.5 X 10 -3 7.0 X 10 -2 , 4.0 X 10 -3 7.0 X 10 -2 , 4.0 X 10 -3 6.5 X 10 -2 , 4.5 X 10 -3 6.5 X 10 -2 , 5.0 X 10 -3 6.5 X 10 -2 , 5.0 X 10 -3 6.0 X 10 -2 , 5.5 X 10 -3 6.0 X 10 -2 , or 6.0 X 10 -3 5.5 X 10 -2 It could be a mistake.

[0124] As an example, in the above equation 3, y may be 5 minutes and z may be 40 minutes; or y may be 40 minutes and z may be 5 minutes. In this case, B may be 2.0 X 10 -3 7.0 X 10 -2, 2.5 X 10 -3 7.0 X 10 -2 , 3.0 X 10 -3 7.0 X 10 -2 , 3.0 X 10 -3 6.5 X 10 -2 , 3.5 X 10 -3 6.5 X 10 -2 , 4.0 X 10 -3 6.5 X 10 -2 , 4.0 X 10 -3 6.0 X 10 -2 , 4.5 X 10 -3 6.0 X 10 -2 , 5.0 X 10 -3 6.0 X 10 -2 , 5.0 X 10 -3 5.5 X 10 -2 , or 5.0 X 10 -3 5.0 X 10 -2 It could be a mistake.

[0125] As an example, in the above equation 3, y may be 5 minutes and z may be 50 minutes; or y may be 50 minutes and z may be 5 minutes. In this case, B may be 1.5 X 10 -3 6.0 X 10 -2 , 2.0 X 10 -3 6.0 X 10 -2 , 2.5 X 10 -3 6.0 X 10 -2 , 2.5 X 10 -3 5.5 X 10 -2 , 3.0 X 10 -3 5.5 X 10 -2 , 3.5 X 10 -3 5.5 X 10 -2 , 3.5 X 10 -3 5.0 X 10 -2 , 3.5 X 10 -3 4.5 X 10 -2 , 3.5 X 10 -3 4.0 X 10 -2, 4.0 X 10 -3 3.5 X 10 -2 , or 4.0 X 10 -3 3.0 X 10 -2 It could be a mistake.

[0126] As an example, in the above equation 3, y may be 5 minutes and z may be 60 minutes; or y may be 60 minutes and z may be 5 minutes. In this case, B may be 1.0 X 10 -3 6.0 X 10 -2 , 1.5 X 10 -3 6.0 X 10 -2 , 2.0 X 10 -3 6.0 X 10 -2 , 2.0 X 10 -3 5.5 X 10 -2 , 2.5 X 10 -3 5.5 X 10 -2 , 2.5 X 10 -3 5.5 X 10 -2 , 3.0 X 10 -3 5.5 X 10 -2 , 3.0 X 10 -3 5.0 X 10 -2 , 3.0 X 10 -3 4.5 X 10 -2 , or 3.0 X 10 -3 4.0 X 10 -2 It could be a mistake.

[0127] The above aerogel composite may have a weight retention of 97% or more, 98% or more, or 99% or more measured after heating at 350°C for 30 minutes.

[0128] The above aerogel composite may have a weight retention of 96% or more, 97% or more, 98% or more, or 99% or more, measured after heating at 350°C for 60 minutes.

[0129] In order to exclude the influence of moisture in the aerogel composite when measuring the change in thermal stability, i.e., weight retention, of the aerogel composite while maintaining the aerogel composite at a high temperature of 350°C for a predetermined period of time, a pre-heat treatment may be performed at 150°C for 1 hour.

[0130] In the above aerogel composite, the moisture impregnation rate (weight%) expressed by Equation 4 below may be 5 weight% or less.

[0131] [Formula 4]

[0132] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0133] In the above equation 4, the moisture impregnation rate can be calculated by floating a specimen of an aerogel composite on distilled water at 21±2℃, placing a 6.4 mm mesh screen on the specimen, submerging it to 127 mm below the water surface, removing the mesh screen after 15 minutes, and when the specimen floats, picking up the specimen with a clamp and hanging it vertically for 60±5 seconds, and then measuring the weight before and after impregnation, respectively, to measure the weight increase rate. Here, a lower moisture impregnation rate indicates a higher degree of hydrophobicity of the aerogel composite.

[0134] The surface water repellency and cross-sectional water repellency for evaluating the degree of hydrophobicity on the surface and the degree of hydrophobicity inside the aerogel composite, respectively, can both be measured using the above equation 4, and can be measured by changing the specimen used at this time. Specifically, the water repellency measured using a relatively large aerogel composite specimen of 100 mm X 100 mm in size, similar to the size of a commercially used aerogel blanket, when measuring the water saturation rate refers to the water repellency on the surface of the aerogel composite. A small surface water saturation rate means a high degree of hydrophobicity on the surface of the aerogel composite. The surface water repellency of the aerogel composite calculated through the above equation 4 may be 5 wt% or less, preferably 4 wt% or less.

[0135] In addition, when measuring the above moisture saturation rate, the moisture saturation rate measured using aerogel composite specimens cut into relatively small pieces, for example, 10 mm X 10 mm in size, refers to the water repellency at the cross-section of the aerogel composite. A small cross-section moisture saturation rate means that the hydrophobicity is high not only on the surface but also on the inside of the aerogel composite. The cross-section water repellency of the aerogel composite calculated through the above equation 4 may be 2 wt% or less, preferably 1.5 wt% or less.

[0136] The above aerogel composite may have a thermal conductivity at room temperature (23±5°C) of 30.0 mW / mK or less, 25.0 mW / mK or less, or 20.0 mW / mK or less, preferably 15.0 mW / mK or less, and has the effect of maximizing the thermal insulation properties of the aerogel composite within this range.

[0137] The above aerogel composite may have a high temperature (150°C) thermal conductivity of 35.0 mW / mK or less, 30.0 mW / mK or less, or 25.0 mW / mK or less, and has the effect of maximizing the thermal insulation properties of the aerogel composite within this range.

[0138] The above aerogel composite may have excellent mechanical strength, with a compressive strength at 10% strain of 20 kPa to 80 kPA, 20 kPa to 70 kPA, 30 kPa to 80 KPa, 30 kPa to 70 kPA, 35 kPa to 80 kPA, or 35 kPa to 70 kPA. Here, the compressive strength may be measured by manufacturing a specimen according to the ASTM C165 standard.

[0139] The above aerogel composite has a tensile strength of 30 N / cm. 2 Up to 60 N / cm 2 , 40 N / cm 2 Up to 55 N / cm 2 , or 45 N / cm 2 Up to 55 N / cm 2 As such, it may have excellent flexibility. Here, the tensile strength may be measured by manufacturing a specimen according to the ASTM D638 standard.

[0140] In the present invention, the aerogel composite can be formed generally through a step of preparing a silica sol; a gelation step after impregnating a fiber substrate with the silica sol; and a drying step. Each step is described below. However, the specific manufacturing process or examples described herein are not intended to be limited to any specific type of aerogel or its manufacturing method. The present invention can include any aerogel formed by any related manufacturing method known to those skilled in the art.

[0141] Steps for preparing silica sol

[0142] In the present invention, a silica sol can be prepared by mixing a silica precursor composition and a catalyst composition.

[0143] The above silica precursor composition may include water and / or a polar organic solvent in the silica precursor.

[0144] The above silica precursor can be any precursor that can be used to form a silica aerogel without limitation, and may be, for example, a silicon-containing alkoxide compound. Specifically, tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetra secondary butyl orthosilicate, tetra tertiary butyl orthosilicate, tetrahexyl orthosilicate, and tetracyclohexyl orthosilicate. It may be a tetraalkyl silicate such as tetracyclohexyl orthosilicate, tetradodecyl orthosilicate, etc. More specifically, among these, the silica precursor may be tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), or a mixture thereof.

[0145] Additionally, 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 alkaline silicic acid salt obtained by melting silicon dioxide (SiO2) and an alkali.

[0146] In addition, the silica precursor may include pre-hydrolyzed TEOS (HTEOS). HTEOS is an ethyl silicate oligomer material having a broad molecular weight distribution. Since the properties such as gelation time can be controlled when synthesizing it in the form of an oligomer from a TEOS monomer, it can be easily applied according to the user's reaction conditions. In addition, it has the advantage of producing reproducible properties of the final product. The HTEOS may be synthesized by a condensation reaction of TEOS that has undergone a partial hydration step under acidic conditions. That is, the HTEOS may be in the form of an oligomer manufactured by condensing TEOS, and the oligomer may be a partially hydrated form.

[0147] The silica concentration of the above silica precursor composition is 10 kg / m 3 Up to 100 kg / m 3 , 20 kg / m 3 Up to 80 kg / m 3 , 30 kg / m 3 Up to 70 kg / m 3 , 30 kg / m 3 Up to 60 kg / m 3 , or 35 kg / m 3 Up to 45 kg / m 3 However, the present invention is not limited thereto. The above silica concentration is the concentration of silica contained in the silica precursor composition, and can be appropriately adjusted by varying the contents of the silica precursor, organic solvent, and water.

[0148] The above silica precursor may be used in an amount such that the silica content contained in the silica sol is 0.1 wt% to 30 wt%, but is not limited thereto. When the silica content satisfies the above range, it is preferable in terms of securing excellent mechanical properties, particularly flexibility, of the aerogel composite while also having an improved insulating effect.

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

[0150] The above polar organic solvent can be used in an appropriate amount by a person skilled in the art, taking into account the degree of hydrophobicity in the final aerogel composite to be manufactured while promoting the surface modification reaction.

[0151] In order to prepare a hydrolyzed silica precursor when preparing the above silica precursor composition, the silica precursor and water may be mixed in a molar ratio of 1:0.5 to 10, 1:1 to 8, or 1:3 to 6, but the present invention is not limited thereto.

[0152] In addition, when the silica precursor composition is manufactured, if a pre-hydrolyzed silica precursor (e.g., pre-hydrolyzed TEOS) is included as the silica precursor, the pre-hydrolyzed silica precursor (e.g., pre-hydrolyzed TEOS) and the organic solvent may be mixed in a weight ratio of 1:0.5 to 5, preferably 1:0.5 to 3.5, to satisfy the silica concentration, but the present invention is not limited thereto.

[0153] The weight ratio of the above hydrolyzed silica precursor and the organic solvent can be appropriately adjusted within the above range so that the weight ratio of the fiber substrate and the aerogel in the final aerogel composite is 1:0.35 to 2, preferably 1:0.4 to 2, or 1:0.4 to 1, more preferably 1:0.45 to 1.

[0154] The above silica precursor composition may further comprise an acid catalyst, and specifically, when an alkoxy silane compound other than a hydrolyzate is used as a precursor, an acid catalyst may be further comprised. At this time, the acid catalyst may be used without limitation as long as it makes the pH 3 or lower, and examples thereof include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, or acetic acid. At this time, the acid catalyst may be added in an amount such that the pH of the sol becomes 3 or lower, and may be added in the form of an aqueous solution dissolved in an aqueous solvent.

[0155] The above catalyst composition may include 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 sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), ammonia (NH3), ammonium hydroxide (NH4OH; ammonia water), 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-(ethyl amino)ethanol, 2-(methyl amino)ethanol, N-methyl diethanolamine, dimethylaminoethanol, diethylaminoethanol, nitrilotriethanol, It may be, but is not limited to, 2-(2-aminoethoxy)ethanol, 1-amino-2-propanol, triethanolamine, monopropanolamine, dibutanolamine, pyridine, or a combination thereof.

[0156] The above base catalyst may be included in an amount such that the pH of the sol is 5 to 9. If the pH of the sol is outside the above range, gelation may not be easy or the gelation speed may be excessively slow, which may lower the processability. In addition, since the base may precipitate when introduced in a solid state, it may be preferable to add it in the form of a solution diluted with an aqueous solvent or the above organic solvent. In this case, the dilution ratio of the base catalyst and the organic solvent, specifically, alcohol, may be 1:4 to 1:100 by volume, but is not limited thereto.

[0157] In order to prepare 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 is not limited thereto.

[0158] When preparing the above silica sol, silica aerogel powder containing at least one organic functional group is added together with the above silica precursor, so that hydrophobic groups can exist even inside the pores during aerogel gelation, thereby increasing hydrophobicity retention, especially at high temperatures.

[0159] The above aerogel powder can be manufactured by sequentially performing supercritical drying and atmospheric pressure drying processes after preparing a silica sol using an alkoxy silane such as tetraethylorthosilicate (TEOS), followed by gelation, and surface modification with a surface modifier such as an alkyltrichlorosilane such as methyltrichlorosilane; a dialkyldichlorosilane such as dimethyldichlorosilane; a trialkylchlorosilane such as trimethylchlorosilane; a symmetrical disiloxane or hexaalkyldisiloxane such as hexamethyldisiloxane; a trialkylaltoxysilane such as trimethylethoxysilane; or a silazane such as hexamethyldisilazane. Here, the composition of the silica precursor, catalyst composition, and organic solvent for preparing the silica sol, or the gelation conditions, etc. overlap with the process for preparing the aerogel composite according to the present invention, and thus, a detailed description thereof is omitted below.

[0160] The average particle size of the above aerogel powder may be 10 to 100 ㎛, preferably 10 to 60 ㎛, but is not limited thereto.

[0161] In order to achieve the above purpose, the aerogel powder may be added in an amount of 5 to 30 parts by weight, preferably 5 to 15 parts by weight, based on 100 parts by weight of silica contained in the silica sol. If the amount of the aerogel powder added is less than the above range, it is difficult to expect the desired effect, and if it exceeds the above range, the strength of the aerogel composite may actually decrease.

[0162] Additionally, additives may be added to the silica sol as needed. Any known additives that can be added during the manufacture of aerogels may be used, including, for example, opacifiers and flame retardants.

[0163] The above additive may be added in an amount of 0.1 wt% to 10 wt%, 0.1 wt% to 7 wt%, 0.5 wt% to 7 wt%, or 0.5 wt% to 5 wt% relative to the silica content of the aerogel, but is not limited thereto.

[0164] Gelation stage of silica sol

[0165] In the present invention, the silica sol can be gelated after impregnating the substrate with the silica sol.

[0166] The above impregnation process is a process for allowing the catalyzed silica sol to penetrate the internal pores of the substrate, and can be performed by placing the catalyzed silica sol and the substrate into a reaction vessel, or by spraying the catalyzed silica sol onto the substrate moving on a conveyor belt according to a roll-to-roll process. At this time, the substrate can be lightly pressed to ensure sufficient impregnation to improve the bonding between the substrate and the silica sol. Afterwards, the material can be pressed to a certain thickness at a certain pressure to remove excess silica sol, thereby reducing the drying time.

[0167] The temperature of the silica sol in the reaction vessel may be 10 to 40°C, 20 to 40°C, 25 to 40°C, 30 to 40°C, or 35 to 45°C. When the temperature of the silica sol in the reaction vessel satisfies the above range, the aforementioned viscosity range of the catalyzed sol can be more easily achieved, and the desired viscosity range can be satisfied even with a relatively short residence time, which is preferable.

[0168] The above catalyzed silica sol can be impregnated into the substrate at 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 0.6 to 1:1, and preferably, it can be impregnated at a volume ratio of 1:1, but is not limited thereto.

[0169] The silica sol impregnated into the substrate can be gelled simultaneously with the impregnation process of the above silica sol or sequentially after the impregnation process.

[0170] In the present specification, the "gelation" may refer to a sol-gel reaction, and the "sol-gel reaction" may be a network structure formed from a silicon unit precursor material. Here, the network structure may refer to a planar net-shaped structure in which a specific polygon having one or more types of atomic arrangements is connected, or a structure in which a three-dimensional skeletal structure is formed by sharing vertices, edges, faces, etc. of a specific polyhedron.

[0171] The above catalyzed sol-impregnated substrate can be gelled on a moving element such as a conveyor belt.

[0172] The above gelation can be performed under an ambient temperature of 20 to 40°C, 25 to 40°C, 30 to 40°C or 35 to 40°C on the conveyor belt, and is particularly preferably performed under an ambient temperature of 30 to 40°C or 35 to 40°C, as this can increase the aerogel and pore strength.

[0173] Additionally, the gelation time may be performed for, 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.

[0174] Maturation stage of the gelled wet gel complex

[0175] The present invention may further include, if necessary, a maturation step in which the wet gel composite obtained through gelation as described above is left at an appropriate temperature to ensure complete chemical change. The maturation step further strengthens the network structure formed through gelation, thereby enhancing the mechanical stability of the aerogel composite.

[0176] The above maturation step can be performed by leaving the gelled wet gel complex at an appropriate temperature as is or by adding a cross-linking promoting compound.

[0177] In addition, in the presence of the wet gel complex 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 at a concentration of 1 to 10% may be added. In this case, there is an effect of maximally inducing Si-O-Si bonds within the aerogel, thereby making the network structure of the silica gel more solid, thereby facilitating the maintenance of the pore structure in the subsequent drying process. At this time, the organic solvent may be the aforementioned alcohol, and specifically, may include ethanol.

[0178] The above maturation step can be carried out by leaving the mixture at a temperature of 30 to 80°C, 40 to 80°C, or 50 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 pore structure, and within this range, a decrease in productivity can be prevented, while loss of solvent due to evaporation can be prevented, thereby preventing an increase in production costs.

[0179] In addition, the above aging step may be performed firstly by leaving the mixture at 30 to 80°C for 0.1 to 5 hours to strengthen the pore structure, and then secondly by aging the mixture at 30 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 in which a base catalyst is diluted in an organic solvent at a concentration of 1 to 10%.

[0180] The above maturation step may be performed in a separate reaction vessel after recovering the gelled wet gel composite, or may be performed inside the reaction vessel in which the gelling step was performed.

[0181] Surface modification step of wet gel composite

[0182] In the present invention, if necessary, a surface modification step may be further included to hydrophobize the surface of the wet gel composite obtained by gelation as described above or the matured wet gel composite in the presence of a surface modifier.

[0183] The above surface modifier may be applied without limitation to any compound that hydrophobicizes the wet gel surface, and may be, for example, a silane-based compound, a siloxane-based compound, a silanol-based compound, a silazane-based compound, or a combination thereof. Specific examples include silane compounds including trimethylchlorosilane (TMCS), dimethyldimethoxysilane, dimethyl diethoxysilane, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), vinyltrimethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, dimethyldichlorosilane, 3-aminopropyltriethoxysilane, etc.; siloxane compounds including polydimethyl siloxane, polydiethyl siloxane, or octamethyl cyclotetrasiloxane, etc.; Silanol compounds including trimethylsilanol, triethylsilanol, triphenylsilanol, and t-butyldimethylsilanol; Silazane compounds including 1,2-diethyldisilazane, 1,1,2,2-tetramethyldisilazane, 1,1,3,3-tetramethyl disilazane, 1,1,1,2,2,2-hexamethyldisilazane (HMDS), 1,1,2,2-tetraethyldisilazane, or 1,2-diisopropyldisilazane; or a combination thereof, but is not limited thereto.

[0184] The above surface modifier may be used in the form of a solution diluted in an organic solvent. Here, the organic solvent may be alcohol (organic solvent), and the surface modifier may be diluted to 1 to 15% by volume based on the total volume of the diluted solution.

[0185] In addition, the surface modifier may be added in an amount of 0.01 to 90 volume% to the wet gel composite to achieve a sufficient surface modification effect, but is not limited thereto.

[0186] The above surface modification step may be performed at a temperature of 50 to 90°C or 50 to 80°C for 1 to 24 hours, but is not limited thereto.

[0187] Drying stage (or drying and surface modification stage)

[0188] The present invention may include a drying step of drying the wet gel composite to obtain an aerogel composite.

[0189] The above drying is performed by a process of removing only the solvent while maintaining the pore structure of the matured gel, and can be performed by, for example, supercritical drying and / or atmospheric pressure drying.

[0190] The above supercritical drying process is performed using supercritical carbon dioxide. For example, a matured wet gel composite is placed in a supercritical drying reactor, then liquid CO2 is filled, and a solvent substitution process is performed to replace the alcohol solvent inside the wet gel with CO2. Then, the temperature is increased to a temperature of 40 to 70°C at a constant temperature increase rate, for example, 0.1 to 1°C / min, and then a pressure higher than the pressure at which carbon dioxide becomes supercritical, for example, a pressure of 100 to 150 bar, is maintained so that the carbon dioxide can be maintained in the 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 73.8 bar. An aerogel composite can be manufactured by maintaining the carbon dioxide at a certain temperature and pressure at which it becomes supercritical for 2 to 12 hours, more specifically, 2 to 6 hours, and then gradually removing the pressure to complete the supercritical drying process, but is not limited thereto.

[0191] In addition, the above atmospheric pressure drying process can be performed according to a conventional method 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 thereto.

[0192] However, the present invention may include not only a method for drying a surface-modified wet gel composite, but also a method for performing surface modification during supercritical drying of a matured or un-matured wet gel composite.

[0193] When surface modification is performed during supercritical drying as described above, the surface modifier may be added at a point when the solvent extraction rate during supercritical drying is 70 wt% or more, 75 wt% or more, or 80 wt% or more. By adding the surface modifier when the solvent extraction rate within the supercritical extractor falls within the above range, the aerogel composite can have excellent hydrophobicity, and in particular, an aerogel composite with excellent hydrophobicity retention even under high-temperature environments can be manufactured.

[0194] Here, the “solvent extraction rate” is the ratio of the amount of solvent recovered from the bottom of the extractor in the supercritical drying step to the total amount of solvent contained in the wet gel composite, and can be calculated by the following equation 5.

[0195] [Formula 5]

[0196] Solvent extraction rate (%) = {(amount of solvent discharged and recovered from the extractor) / (amount of solvent in the wet gel complex fed into the extractor)} X 100 (%)

[0197] In the above equation 5, the weight of the solvent discharged and recovered from the extractor is the weight of the solvent obtained from the extraction solvent separator after drying, and the total amount of solvent included in the wet gel composite is the difference between the weight of the aerogel composite after drying and the weight of the wet gel composite before drying.

[0198] In the present invention, the surface modifier may be any compound that hydrophobizes the wet gel surface without limitation, and may be, for example, a silane-based compound, a siloxane-based compound, a silanol-based compound, a silazane-based compound, or a combination thereof. Specific examples include silane compounds including trimethylchlorosilane (TMCS), dimethyldimethoxysilane, dimethyl diethoxysilane, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), vinyltrimethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, dimethyldichlorosilane, 3-aminopropyltriethoxysilane, etc.; siloxane compounds including polydimethyl siloxane, polydiethyl siloxane, or octamethyl cyclotetrasiloxane, etc.; Silanol compounds including trimethylsilanol, triethylsilanol, triphenylsilanol, and t-butyldimethylsilanol; Silazane compounds including 1,2-diethyldisilazane, 1,1,2,2-tetramethyldisilazane, 1,1,3,3-tetramethyl disilazane, 1,1,1,2,2,2-hexamethyldisilazane (HMDS), 1,1,2,2-tetraethyldisilazane, or 1,2-diisopropyldisilazane; or a combination thereof, but is not limited thereto.

[0199] The above surface modifier may be added in an amount of 1 to 20 parts by weight, preferably 5 to 15 parts by weight, based on 100 parts by weight of the wet gel, but is not limited thereto. Here, the wet gel refers to the weight of the wet gel itself excluding the weight of the fiber substrate.

[0200] The solvent used in the above supercritical drying may be the solvent previously used in the production of the wet gel composite, and may include water and an organic solvent. In addition, the organic solvent may specifically be an alcohol, and at this time, the alcohol may be a monohydric alcohol such as methanol, ethanol, isopropanol, butanol, etc.; or a polyhydric alcohol such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and sorbitol, etc., and one or a mixture of two or more thereof may be used. Among these, considering the miscibility with water and aerogel, a monohydric alcohol having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, butanol, etc., preferably ethanol, may be used.

[0201] Additionally, the solvent may comprise 85 to 95 wt% of an organic solvent and 5 to 15 wt% of water.

[0202] In addition, when introducing the wet gel complex into the supercritical extractor during the supercritical drying, it is preferable to introduce the wet gel complex in an amount of 50% by volume or more based on 100% by volume of the supercritical extractor volume, so that an environment can be created in which even the remaining solvent can be converted to a supercritical state when the surface modifier is subsequently introduced.

[0203] It is preferable that the drying step including the above-described silica sol preparation step, impregnation step and surface modification step is designed so that the volume ratio of fibers per unit volume of the aerogel composite manufactured after the final drying is included at 2 to 12%, or 5 to 10%, and the volume ratio of voids between the aerogel including pores and the discrete fibers, excluding the fibers, is 88 to 98%, or 90 to 95%, and further, the aerogel composite is included in a weight ratio of the fiber substrate and the aerogel at 1:0.4 to 2, preferably 1:0.4 to 1, or 1:0.45 to 1. It is preferable that the aerogel composite includes the fibers and the aerogel including pores and air voids at the above-described volume ratio because it has excellent thermal insulation properties, excellent hydrophobicity even within the pores or air voids, and excellent ability to withstand high temperatures, i.e., excellent thermal stability.

[0204] In this way, the aerogel composite provided by the present invention has excellent high-temperature insulation properties, and thus can exhibit excellent heat blocking ability when applied as an insulation material to high-temperature pipes or battery modules of electric vehicles, etc.

[0205]

[0206] According to another embodiment of the present invention, there is provided an insulating member comprising an aerogel composite provided by the present invention.

[0207] The above insulating member may include the above-described aerogel composite and a support member positioned on at least one of the two surfaces of the aerogel composite.

[0208] Examples of the above-mentioned support member include a film-like support member, a sheet-like support member, a thin support member, a porous support member, and the like.

[0209] The above film-shaped support member is formed by forming a polymer raw material into a thin film, and may include organic films such as PET (polyethylene terephthalate), polyester, PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate), PEEK (polyether ether ketone), PAR (polyarylate), PCO (polycylicolefin), polynorbornene, PES (polyethersulphone), and COP (cycloolefin polymer), glass films, etc. (also including metal deposition films).

[0210] The above sheet-like support member is formed from a fiber-like raw material of organic, inorganic or metallic origin, and may include paper, non-woven fabric (including glass mat), organic fiber fabric, glass cloth, etc.

[0211] The above-mentioned thin support member is formed by forming a metal raw material into a thin film, and examples thereof include aluminum foil, copper foil, etc.

[0212] The above porous support member has a porous structure made of organic, inorganic or metal raw materials, and examples thereof 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).

[0213] The above support member may be a single-layer structure or a multi-layer structure having two or more layers.

[0214] The thickness of the above-mentioned support member is not particularly limited and may be, for example, 0.1 to 100 μm, or 1 to 50 μm.

[0215] Additionally, the present invention may further include an adhesive layer or bonding layer between the exposed surface of the aerogel composite and the support member.

[0216] The above adhesive layer or adhesive layer may include, but is not limited to, an acrylic adhesive, a polyurethane adhesive, an olefin adhesive, an SBR rubber adhesive, or a silicone adhesive.

[0217] There is no particular limitation on the thickness of the adhesive layer or bonding layer, and it may be, for example, 1 to 100 μm or 10 to 50 μm.

[0218] The above insulating material can also be applied as an insulating material, heat blocking material, or flame retardant material in the construction, aviation, automobile, battery, home appliance, semiconductor, and industrial facilities fields.

[0219]

[0220] According to another embodiment of the present invention, there is provided a battery module or battery pack comprising an aerogel composite according to the present invention.

[0221] The battery module may include a module case having an internal space and one or more battery cells located within the internal space. The number of battery cells accommodated in the module case is not particularly limited and may be adjusted according to the purpose of the battery module. The battery cells accommodated in the module case may be electrically connected to each other. The type of battery cells accommodated in the module case is not limited, but for example, the battery module may include cylindrical, square, or pouch-shaped case battery cells.

[0222] The battery module may include an aerogel composite according to the present disclosure within a module case of the battery module. The aerogel composite may be positioned between battery cells accommodated within the module case. The aerogel composite may be positioned between the module case and a plurality of battery cells, i.e., at the periphery of the module case. The aerogel composite positioned within the module case may act as an insulator, thereby reducing heat transfer within the battery module and enhancing the safety of the battery module.

[0223] The battery pack may include one or more of the battery modules. In the battery pack, the battery modules may be electrically connected to each other. The battery pack may include an aerogel composite according to the present disclosure. For example, the aerogel composite may be positioned between the battery modules of the battery pack. The aerogel composite may also at least partially surround a plurality of battery modules within the battery pack. The aerogel composite may act as an insulating material within the battery pack, thereby reducing heat transfer and enhancing the safety of the battery pack.

[0224]

[0225] Hereinafter, the present invention will be described in detail 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.

[0226]

[0227] Example

[0228]

[0229] [Preparation Example 1] Preparation of aerogel powder

[0230] 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 to TEOS. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:1.67 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the obtained silica sol. This catalyzed sol was placed in a container and gelation was performed. After gelation was completed, a solution (2 vol%) of trimethylethoxysilane (TMES) diluted in ethanol as a surface modifier was added to the wet gel in an amount of 90 vol% based on the wet gel volume, and then surface modification was performed at a temperature of 75 °C for 12 hours. At this time, in order to increase the surface modification efficiency, the wet gel in the form of a monolith can be cut into pieces of several cm in size and then surface modification can be performed. After the surface modification is complete, the wet gel is placed in a 70 L supercritical extractor, and CO2 is injected at 28 ℃ and 70 bar, continuously at a rate of 70 L / min for 10 minutes. After that, the temperature inside the extractor is increased to 50 ℃ over 1 hour and 20 minutes, and when it reaches 50 ℃ and 150 bar, CO2 is continuously injected at a rate of 5 L / min for 20 minutes. At this time, ethanol is recovered through the bottom of the separator. After a 20-minute rest, supercritical drying is performed by continuously injecting CO2 at a rate of 5 L / min again over 20 minutes. After that, CO2 is vented over 2 hours, and silica aerogel is manufactured. The manufactured silica aerogel was pulverized using a RETSCH ZM 200 Ultra Centrifugal Mill to produce hydrophobic aerogel powder classified to have an average particle size in the range of 10 to 100 ㎛.

[0231]

[0232] [Example 1] Preparation of an aerogel composite

[0233] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding TEOS and ethanol in a weight ratio of 1:1. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the solution was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding the hydrated TEOS solution and ethanol in a weight ratio of 1:0.73. Then, the prepared aerogel powder was added to the prepared silica sol in an amount of 10 parts by weight based on 100 parts by weight of silica in the silica sol. A catalyzed sol was prepared by adding the obtained silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol. The fibers, which had passed through the impregnation tank and were infiltrated with the catalyzed sol, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 30°C. The manufactured wet gel composite was then placed in a supercritical extractor, heated to 70°C, and pressurized to 150 bar, and maintained at this temperature for 20 minutes. Thereafter, supercritical carbon dioxide was continuously injected for 20 minutes to extract the solvent, and the mixture was allowed to rest (stand) for 20 minutes. The supercritical carbon dioxide injection and resting process was repeated once more, and after the third continuous injection of supercritical carbon dioxide, hexamethyldisilazane (HMDS) was added at 5 parts by weight based on 100 parts by weight of the wet gel. The solvent extraction rate when hexamethyldisilazane was added was 85 wt%. After maintaining the resting state for 20 minutes, supercritical carbon dioxide was continuously injected. After this, the pressure was reduced to atmospheric pressure, and supercritical drying was completed. At this time, supercritical drying took a total of 4 hours. Afterwards, additional atmospheric pressure drying was performed in an oven at 150°C to produce an aerogel composite.

[0234]

[0235] [Example 2] Preparation of an aerogel composite

[0236] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol having a weight ratio of 1:1 to TEOS. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the solution was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol having a weight ratio of 1:1.1 to the hydrated TEOS solution. Subsequently, the prepared aerogel powder was added to the prepared silica sol in an amount of 15 parts by weight based on 100 parts by weight of silica in the silica sol. A catalyzed sol was prepared by adding the obtained silica sol to a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol. The fibers, which had passed through the impregnation tank and were infiltrated with the catalyzed sol, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 40°C. The manufactured wet gel composite was then placed in a supercritical extractor, heated to 70°C, and pressurized to 150 bar, and maintained at this temperature for 20 minutes. Thereafter, supercritical carbon dioxide was continuously injected for 20 minutes to extract the solvent, and the mixture was allowed to rest (stand) for 20 minutes. The supercritical carbon dioxide injection and resting process was repeated once more, and after the third continuous injection of supercritical carbon dioxide, hexamethyldisilazane (HMDS) was added at 10 parts by weight based on 100 parts by weight of the wet gel. The solvent extraction rate when hexamethyldisilazane was added was 75 wt%. After maintaining the resting state for 20 minutes, supercritical carbon dioxide was continuously injected. After this, the pressure was reduced to atmospheric pressure, and supercritical drying was completed. At this time, supercritical drying took a total of 4 hours. Afterwards, additional atmospheric pressure drying was performed in an oven at 150°C to produce an aerogel composite.

[0237]

[0238] [Example 3] Preparation of an aerogel composite

[0239] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding TEOS and ethanol in a weight ratio of 1:1. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the solution was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding the hydrated TEOS solution and ethanol in a weight ratio of 1:1.5. Then, the prepared aerogel powder was added to the prepared silica sol in an amount of 5 parts by weight based on 100 parts by weight of silica in the silica sol. A catalyzed sol was prepared by adding the obtained silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol. The fibers, which had passed through the impregnation tank and were infiltrated with the catalyzed sol, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 35°C. The manufactured wet gel composite was then placed in a supercritical extractor, heated to 70°C, and pressurized to 150 bar, and maintained at this temperature for 20 minutes. Thereafter, supercritical carbon dioxide was continuously injected for 20 minutes to extract the solvent, and the mixture was allowed to rest (stand) for 20 minutes. The supercritical carbon dioxide injection and resting process was repeated once more, and after the third continuous injection of supercritical carbon dioxide, hexamethyldisilazane (HMDS) was added at 5 parts by weight based on 100 parts by weight of the wet gel. The solvent extraction rate when hexamethyldisilazane was added was 70% by weight. After maintaining the resting state for 20 minutes, supercritical carbon dioxide was continuously injected. After this, the pressure was reduced to atmospheric pressure, and supercritical drying was completed. At this time, supercritical drying took a total of 4 hours. Afterwards, additional atmospheric pressure drying was performed in an oven at 150°C to produce an aerogel composite.

[0240]

[0241] [Example 4] Preparation of an aerogel composite

[0242] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol having a weight ratio of 1:1 to TEOS. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the solution was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol having a weight ratio of 1:1.33 to the hydrated TEOS solution. Then, the prepared aerogel powder was added to the prepared silica sol in an amount of 5 parts by weight based on 100 parts by weight of silica in the silica sol. A catalyzed sol was prepared by adding the obtained silica sol to a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol. The fibers, which had passed through the impregnation tank and were infiltrated with the catalyzed sol, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 40°C. The manufactured wet gel composite was then placed in a supercritical extractor, heated to 70°C, and pressurized to 150 bar, and maintained at this temperature for 20 minutes. Thereafter, supercritical carbon dioxide was continuously injected for 20 minutes to extract the solvent, and the mixture was allowed to rest (stand) for 20 minutes. The above supercritical carbon dioxide injection and resting process was repeated once more, and after the third continuous injection of supercritical carbon dioxide, hexamethyldisilazane (HMDS) was added at 5 parts by weight based on 100 parts by weight of the wet gel. The solvent extraction rate when hexamethyldisilazane was added was 75 wt%. After maintaining the resting state for 20 minutes, supercritical carbon dioxide was continuously injected. After this, the pressure was reduced to atmospheric pressure, and supercritical drying was completed. At this time, supercritical drying took a total of 4 hours. Afterwards, additional atmospheric pressure drying was performed in an oven at 150°C to produce an aerogel composite.

[0243]

[0244] [Example 5] Preparation of an aerogel composite

[0245] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding TEOS and ethanol in a weight ratio of 1:1. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the solution was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding the hydrated TEOS solution and ethanol in a weight ratio of 1:1.4. Then, the prepared aerogel powder was added to the prepared silica sol in an amount of 10 parts by weight based on 100 parts by weight of silica in the silica sol. A catalyzed sol was prepared by adding the obtained silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol. The fibers, which had passed through the impregnation tank and were infiltrated with the catalyzed sol, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 35°C. The manufactured wet gel composite was then placed in a supercritical extractor, heated to 70°C, and pressurized to 150 bar, and maintained at this temperature for 20 minutes. Thereafter, supercritical carbon dioxide was continuously injected for 20 minutes to extract the solvent, and the mixture was allowed to rest (stand) for 20 minutes. The above supercritical carbon dioxide injection and resting process was repeated once more, and after the third continuous injection of supercritical carbon dioxide, hexamethyldisilazane (HMDS) was added at 10 parts by weight based on 100 parts by weight of the wet gel. The solvent extraction rate when hexamethyldisilazane was added was 80 wt%. After maintaining the resting state for 20 minutes, supercritical carbon dioxide was continuously injected. After this, the pressure was reduced to atmospheric pressure, and supercritical drying was completed. At this time, supercritical drying took a total of 4 hours. Afterwards, additional atmospheric pressure drying was performed in an oven at 150°C to produce an aerogel composite.

[0246]

[0247] [Comparative Example 1] Preparation of an aerogel composite

[0248] 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 to TEOS. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:2 to the hydrated TEOS solution. A catalyzed sol was prepared by adding the obtained silica sol to a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol. The fiber, which had passed through the impregnation tank and had been permeated with the catalyzed sol, passed along a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 30°C. After adding 80 vol% of hexamethyldisilazane (HMDS) / ethanol solution (volume ratio 1:19) as a surface modifier to the wet gel composite based on the volume of the wet gel composite, surface modification was performed at 70 ℃ for 3 hours. After completion of surface modification, the wet gel composite was placed in a 70 L supercritical extractor, and CO2 was injected at 28 ℃ and 70 bar, continuously at a rate of 70 L / min for 10 minutes. Thereafter, the temperature inside the extractor was increased to 50 ℃ over 1 hour and 20 minutes, and when it reached 50 ℃ and 150 bar, CO2 was continuously injected at a rate of 5 L / min for 20 minutes. At this time, ethanol was recovered through the bottom of the separator. After a 20-minute rest, supercritical drying was performed by continuously injecting CO2 again at a rate of 5 L / min over 20 minutes. CO2 was vented over the next two hours, and a silica aerogel composite was manufactured.

[0249]

[0250] [Comparative Example 2] Manufacturing of an Aerogel Composite

[0251] 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 TEOS to ethanol. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:1.25 to the hydrated TEOS solution. A catalyzed sol was prepared by adding the obtained silica sol to a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol in a volume ratio of 1:1. The fiber, which had passed through the impregnation tank and had been permeated with the catalyzed sol, passed along a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. After the manufactured wet gel composite was placed in a supercritical extractor, the temperature was increased to 70 ℃, the pressure was increased to 150 bar, and the temperature was maintained for 20 minutes. Thereafter, supercritical carbon dioxide was continuously injected for 20 minutes to extract the solvent, and the mixture was allowed to rest (stand) for 20 minutes. The supercritical carbon dioxide injection and resting process was repeated once more, and after the third continuous injection of supercritical carbon dioxide, hexamethyldisilazane (HMDS) was added at 5 parts by weight based on 100 parts by weight of the wet gel. The solvent extraction rate when hexamethyldisilazane was added was 60 wt%. After maintaining the rest state for 20 minutes, supercritical carbon dioxide was continuously injected. Thereafter, the pressure was reduced to atmospheric pressure, and supercritical drying was completed. Supercritical drying took a total of 4 hours. Afterwards, additional atmospheric pressure drying was performed in an oven at 150 ℃ to manufacture an aerogel composite.

[0252]

[0253] [Comparative Example 3] Manufacturing of an aerogel composite

[0254] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol having a weight ratio of 1:1 to TEOS. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the solution was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol having a weight ratio of 1:2.05 to the hydrated TEOS solution. Subsequently, the prepared aerogel powder was added to the prepared silica sol in an amount of 3 parts by weight based on 100 parts by weight of silica in the silica sol. A catalyzed sol was prepared by adding the obtained silica sol to a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol. The fibers, which had been impregnated with the catalyzed sol after passing through the impregnation tank, were gelated while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. The manufactured wet gel composite was then placed in a supercritical extractor, heated to 70°C, and pressurized to 150 bar, and maintained at this temperature for 20 minutes. Thereafter, supercritical carbon dioxide was continuously injected for 20 minutes to extract the solvent, and the mixture was allowed to rest (stand) for 20 minutes. The above supercritical carbon dioxide injection and resting process was repeated once more, and after the third continuous injection of supercritical carbon dioxide, hexamethyldisilazane (HMDS) was added at 3 parts by weight based on 100 parts by weight of the wet gel. The solvent extraction rate when hexamethyldisilazane was added was 70% by weight. After maintaining the resting state for 20 minutes, supercritical carbon dioxide was continuously injected. After this, the pressure was reduced to atmospheric pressure, and supercritical drying was completed. At this time, supercritical drying took a total of 4 hours. Afterwards, additional atmospheric pressure drying was performed in an oven at 150°C to produce an aerogel composite.

[0255]

[0256] [Comparative Example 4] Manufacturing of an Aerogel Composite

[0257] 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 TEOS to ethanol. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:2.6 to the hydrated TEOS solution. A catalyzed sol was prepared by adding the obtained silica sol to a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol in a volume ratio of 1:1. The fiber, which had passed through the impregnation tank and had been permeated with the catalyzed sol, passed along a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. After adding 80 vol% of hexamethyldisilazane (HMDS) / ethanol solution (volume ratio 1:19) as a surface modifier to the wet gel composite based on the volume of the wet gel composite, surface modification was performed at 70 ℃ for 4 hours. After completion of surface modification, the wet gel composite was placed in a 70 L supercritical extractor, and CO2 was injected at 28 ℃ and 70 bar, continuously at a rate of 70 L / min for 10 minutes. Thereafter, the temperature inside the extractor was increased to 50 ℃ over 1 hour and 20 minutes, and when it reached 50 ℃ and 150 bar, CO2 was continuously injected at a rate of 5 L / min for 20 minutes. At this time, ethanol was recovered through the bottom of the separator. After a 20-minute rest, supercritical drying was performed by continuously injecting CO2 again at a rate of 5 L / min over 20 minutes. CO2 was vented over the next two hours, and a silica aerogel composite was manufactured.

[0258]

[0259] [Comparative Example 5] Manufacturing of an aerogel composite

[0260] 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 TEOS to ethanol. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:3.4 to the hydrated TEOS solution. A catalyzed sol was prepared by adding the obtained silica sol to a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated with the catalyzed sol in a volume ratio of 1:1. The fiber, which had passed through the impregnation tank and had been permeated with the catalyzed sol, passed along a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 20°C. After adding 80 vol% of hexamethyldisilazane (HMDS) / ethanol solution (volume ratio 1:19) as a surface modifier to the wet gel composite based on the volume of the wet gel composite, surface modification was performed at 70 ℃ for 4 hours. After completion of surface modification, the wet gel composite was placed in a 70 L supercritical extractor, and CO2 was injected at 28 ℃ and 70 bar, continuously at a rate of 70 L / min for 10 minutes. Thereafter, the temperature inside the extractor was increased to 50 ℃ over 1 hour and 20 minutes, and when it reached 50 ℃ and 150 bar, CO2 was continuously injected at a rate of 5 L / min for 20 minutes. At this time, ethanol was recovered through the bottom of the separator. After a 20-minute rest, supercritical drying was performed by continuously injecting CO2 again at a rate of 5 L / min over 20 minutes. CO2 was vented over the next two hours, and a silica aerogel composite was manufactured.

[0261]

[0262] [Experimental Example 1] Volume ratio of fibers and remaining parts per unit volume of aerogel composite

[0263] In order to confirm the volume ratio of the fibers and the remaining portion, i.e., the voids between the aerogel including pores and the discrete fibers, in the silica aerogel composites manufactured in Examples 1 to 5 and Comparative Examples 1 to 5, which were finally dried as described above, the following experiment was performed.

[0264] First, the aerogel composites of Examples 1 to 1 and Comparative Examples 1 to 5, which were manufactured to have a width X length of approximately 60 cm X 12 cm and a height of approximately 0.4 cm, were prepared, and then five rectangular parallelepiped specimens each having a width X length of 1 cm X 1 cm were obtained from each aerogel composite. However, at this time, four specimens were obtained by ensuring that the positions spaced 10 cm apart from each edge of the aerogel composite in the center direction were located at the exact center of the specimens, and one specimen was obtained by ensuring that the exact center of the aerogel composite was also located at the exact center of the specimen.

[0265] After placing the specimen on the DEBEN load cell, the load cell was assembled, and the stage of the equipment was changed to a dedicated stage that can fix the load cell. At this time, in-situ XRM analysis was performed using the VERSA 520 equipment from ZEISS under the conditions shown in Table 1 below. Based on the analysis results, Dragonfly software (version 2021.3) was used to confirm the volume ratio of the aerogel, including fibers, pores, and air voids in the aerogel composite specimen. To help understand the analysis method, an example process of the analysis is described below with reference to Figures 1 to 3. After the result of the in-situ XRM analysis was completed, it was activated with Dragonfly software, and the area to be segmented was set and extracted by adjusting the border using the Clip function (Figure 1). At this time, the size of the segmented area was set to be approximately 1700 μm X 1600 μm X 500 μm (width X depth X height). Within the segmented region, the fibers and the non-fiber portions were distinguished based on contrast using the lower and upper otsu functions of the Dragonfly software (Fig. 2). The lower otsu function identified the low-contrast segmented region corresponding to the non-fiber portion, and the upper otsu function identified the high-contrast segmented region corresponding to the fibers. Then, the volume occupancy rate (volume ratio) of the fibers and the non-fiber portions was calculated using the Dragonfly software (Fig. 3). Through the above analysis, the average values ​​of the volume ratio of the fibers per unit volume of the aerogel composite measured for each example or comparative example and the volume ratio of the aerogel including the voids and pores between the discrete fibers were calculated for five specimens, and these values ​​are shown in Table 2 below.

[0266] Acceleration voltage 80 kV Voxel size 2.5 μm Objective lens magnification 4X Exposure time 1 s / frame Total number of frames 3201

[0267] Volume ratio of fibers per unit volume of aerogel composite (%) Volume ratio of remaining portion excluding fibers per unit volume of aerogel composite (%) Example 19.790.3 Example 27.492.6 Example 36.593.5 Example 48.891.2 Example 58.591.5 Comparative Example 122.977.1 Comparative Example 213.686.4 Comparative Example 315.484.6 Comparative Example 423.876.2 Comparative Example 525.474.6

[0268] As shown in Table 2 above, the silica aerogel composites manufactured in Examples 1 to 5 contain 2 to 12 volume% of fibers per unit volume, and the remaining portion, excluding the fibers, contains 88 to 98 volume% of voids between the aerogel containing pores and the discrete fibers.

[0269]

[0270] [Experimental Example 2] Weight ratio of fiber substrate and aerogel in an aerogel composite

[0271] As described above, the weights of the silica aerogel composites manufactured in Examples 1 to 5 and Comparative Examples 1 to 5, which were finally dried as described above, were measured. In addition, the fiber substrate used in the aerogel composite was subjected to supercritical drying and atmospheric pressure drying in the same manner as in Comparative Example 1, and then the weights were measured. Assuming that the difference between the weight of the silica aerogel composite and the weight of the fiber substrate is the weight of the aerogel, the weight ratios of the fiber substrate and the aerogel in each Example and Comparative Example were calculated and shown in Table 3 below.

[0272] Weight ratio of fiber: aerogel Example 11:0.7 Example 21:0.6 Example 31:0.45 Example 41:0.5 Example 51:0.5 Comparative Example 11:0.375 Comparative Example 21:0.5 Comparative Example 31:0.375 Comparative Example 41:0.3 Comparative Example 51:0.25

[0273] As shown in Table 3 above, it can be seen that the fiber substrate and the aerogel in the silica aerogel composites manufactured in Examples 1 to 5 are included in a weight ratio of 1:0.4 to 1.

[0274]

[0275] [Experimental Example 3] Evaluation of thermal stability at a high temperature of 350 ℃

[0276] In order to evaluate the thermal stability of the aerogel composite manufactured according to the present invention at a high temperature of 350 ℃, the aerogel composites manufactured in the above examples and comparative examples were maintained at an isothermal temperature of 350 ℃ for 1 hour, and the weight retention rate of the aerogel composites according to the change in time was analyzed. For this analysis, specimens measuring 10 cm X 10 cm were obtained from each of the aerogel composites of Examples 1 to 5 and Comparative Examples 1 to 5. After that, the temperature inside the furnace (Changshin science C-FMD) was heated to 350 ℃, the aerogel composite specimens were placed therein, and maintained for 1 hour. The weight reduction rate of the specimens compared to the initial value (after heat treatment at 150 ℃ for 1 hour) was measured, and the results are shown in Table 4 below. In addition, in order to confirm the change in weight loss over time, the average value (b) of the weight retention rates measured at 5, 10, 15, 20, 25, and 30 minutes was calculated, and the difference between the weight retention rate (a) and the average value at each time, and the percentage (A) of the difference compared to the average value (b) were calculated and shown in Table 5 below. However, in Table 5 below, the weight retention rate (a) and the average value (b) were rounded off to the third decimal place and shown to the second decimal place. The deviation percentage (A) was rounded off to the fifth decimal place and shown to the fourth decimal place.

[0277] [Formula 2]

[0278] A (%) = {(Weight retention rate measured after heating for x minutes (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0279] Example 1 Hour (% by weight) Weight retention rate Weight loss rate 5 minutes (300 seconds) 98.43 1.57 10 minutes (600 seconds) 98.23 1.77 15 minutes (900 seconds) 98.15 1.85 20 minutes (1200 seconds) 98.09 1.91 25 minutes (1500 seconds) 98.05 1.95 30 minutes (1800 seconds) 98.02 1.98 40 minutes (2400 seconds) 97.96 2.04 50 minutes (3000 seconds) 97.91 2.09 60 minutes (3600 seconds) 97.88 2.12 Example 2 Hour Weight retention rate Weight loss rate 5 minutes (300 seconds) sec)99.450.5510 minutes (600 seconds)99.340.6615 minutes (900 seconds)99.320.6820 minutes (1200 seconds)99.280.7225 minutes (1500 seconds)99.280.7230 minutes (1800 seconds)99.250.7540 minutes (2400 seconds)99.230.7750 minutes (3000 seconds)99.210.7960 minutes (3600 seconds)99.190.81Example 3 hoursWeight retention rateWeight loss rate5 minutes (300 sec)99.260.7410 minutes (600 seconds)99.080.9215 minutes (900 seconds)98.831.1720 minutes (1200 seconds)98.621.3825 minutes (1500 seconds)98.171.8330 minutes (1800 seconds)97.932.0740 minutes (2400 seconds)97.772.2350 minutes (3000 seconds)97.622.3860 minutes (3600 seconds)97.312.69Example 4 hoursWeight retention rateWeight loss rate5 minutes (300 sec)98.571.4310 minutes (600 seconds)98.321.6815 minutes (900 seconds)98.261.7420 minutes (1200 seconds)98.181.8225 minutes (1500 seconds)98.021.9830 minutes (1800 seconds)97.892.1140 minutes (2400 seconds)97.732.2750 minutes (3000 seconds)97.572.4360 minutes (3600 seconds)97.402.60Example 5 hoursWeight retention rateWeight loss rate5 minutes (300 sec)98.211.7910 minutes (600 seconds)98.121.8815 minutes (900 seconds)98.061.9420 minutes (1200 seconds)97.992.0125 minutes (1500 seconds)97.982.0230 minutes (1800 seconds)97.952.0540 minutes (2400 seconds)97.902.1050 minutes (3000 seconds)97.872.1360 minutes (3600 seconds)97.852.15Comparison Example 1 hourWeight maintenance rateWeight loss rate5 minutes (300 seconds)97.502.5010 minutes (600 seconds)94.665.3415 minutes (900 seconds)93.826.1820 minutes (1200 seconds) 93.676.3325 minutes (1500 seconds) 93.576.4330 minutes (1800 seconds) 93.506.5040 minutes (2400 seconds) 93.436.5750 minutes (3000 seconds) 93.376.6360 minutes (3600 seconds) 93.326.68Comparative Example 2 Hours Weight Maintenance Rate Weight Loss Rate 5 minutes (300 sec)99.100.9010 minutes (600 seconds)98.231.7715 minutes (900 seconds)97.822.1820 minutes (1200 seconds)97.562.4425 minutes (1500 seconds)96.873.1330 minutes (1800 seconds)95.724.2840 minutes (2400 seconds)94.965.0450 minutes (3000 seconds)94.765.2460 minutes (3600 seconds)94.595.41Comparison Example 3 hoursWeight maintenance rateWeight loss rate5 minutes (300 sec)99.790.2110 minutes (600 seconds)98.511.4915 minutes (900 seconds)97.792.2120 minutes (1200 seconds)97.132.8725 minutes (1500 seconds)96.303.7030 minutes (1800 seconds)95.834.1740 minutes (2400 seconds)95.124.8850 minutes (3000 seconds)94.465.5460 minutes (3600 seconds)94.025.98Comparison Example 4 hoursWeight maintenance rateWeight loss rate5 minutes (300 sec)98.631.3710 minutes (600 seconds)97.462.5415 minutes (900 seconds)97.012.9920 minutes (1200 seconds)96.583.4225 minutes (1500 seconds)96.123.8830 minutes (1800 seconds)94.975.0340 minutes (2400 seconds)94.205.8050 minutes (3000 seconds)93.826.1860 minutes (3600 seconds)92.797.21Comparison Example 5 hoursWeight maintenance rateWeight loss rate5 minutes (300 sec)97.522.4810 minutes (600 seconds)96.983.0215 minutes (900 seconds)96.113.8920 minutes (1200 seconds)95.624.3825 minutes (1500 seconds)95.134.8730 minutes (1800 seconds)94.385.6240 minutes (2400 seconds)93.776.2350 minutes (3000 seconds)93.146.8660 minutes (3600 seconds)92.637.37.

[0280] Example 1 Hour (% weight) Weight retention rate (a) Average value (b) Deviation (ab) Deviation percentage (A (%)) 5 minutes (300 seconds) 98.43 98.16 0.27 0.27 5 110 minutes (600 seconds) 98.23 0.07 0.07 13 15 minutes (900 seconds) 98.15 - 0.01 - 0.01 0 2 20 minutes (1200 seconds) 98.09 - 0.07 - 0.07 13 25 minutes (1500 seconds) 98.05 - 0.11 - 0.11 2 130 minutes (1800 seconds) 98.02 - 0.14 - 0.14 26 Example 2 Hour Weight retention rate (a) Average value (b) Deviation (ab) Deviation percentage (A (%)) 5 minutes (300 seconds) sec)99.4599.320.130.130910 minutes (600 seconds)99.340.020.020115 minutes (900 seconds)99.3200.000020 minutes (1200 seconds)99.28-0.04-0.040325 minutes (1500 seconds)99.28-0.04-0.040330 minutes (1800 seconds)99.25-0.07-0.0705Example 3 Hours Weight Retention Rate (a)Average Value (b)Deviation (ab)Deviation Percentage (A(%))5 minutes (300 sec)99.2698.650.610.619610 minutes (600 seconds)99.080.430.436815 minutes (900 seconds)98.830.180.182820 minutes (1200 seconds)98.62-0.03-0.030525 minutes (1500 seconds)98.17-0.48-0.487630 minutes (1800 seconds)97.93-0.72-0.7313Example 4 Hour Weight Retention Rate (a)Average Value (b)Deviation (ab)Deviation Percentage (A(%))5 minutes (300 sec)98.5798.210.360.366610 minutes (600 seconds)98.320.110.112015 minutes (900 seconds)98.260.050.050920 minutes (1200 seconds)98.18-0.03-0.030525 minutes (1500 seconds)98.02-0.19-0.193530 minutes (1800 seconds)97.89-0.32-0.3258Example 5 Hours Weight Retention Rate (a)Average Value (b)Deviation (ab)Deviation Percentage (A (%))5 minutes (300 sec)98.2198.050.160.163210 minutes (600 seconds)98.120.070.071415 minutes (900 seconds)98.060.010.010220 minutes (1200 seconds)97.99-0.06-0.061225 minutes (1500 seconds)97.98-0.07-0.071430 minutes (1800 seconds)97.95-0.1-0.1020Comparative Example 1 Hour Weight Retention Rate (a) Average Value (b) Deviation (ab) Deviation Percentage (A (%)) 5 minutes (300 seconds) 97.50 94.45 3.05 3.22 9 2 10 minutes (600 seconds) 94.66 0.21 0.22 2 3 15 minutes (900 seconds) 93.82 - 0.63 - 0.66 7 0 20 minutes (1200 seconds) 93.67 - 0.78 - 0.82 5 8 25 minutes (1500 seconds) 93.57 - 0.88 - 0.93 1 7 30 minutes (1800 seconds) 93.50 - 0.95 - 1.00 5 8Comparative Example 2 Hour Weight Retention Rate (a) Average Value (b) Deviation (ab) Deviation Percentage (A (%)) 5 minutes (300 seconds) sec)99.1097.551.551.588910 minutes (600 seconds)98.230.680.697115 minutes (900 seconds)97.820.270.276820 minutes (1200 seconds)97.560.010.010325 minutes (1500 seconds)96.87-0.68-0.697130 minutes (1800 seconds)95.72-1.83-1.8760Comparative example 3 hours Weight retention rate (a) Average value (b) Deviation (ab) Deviation percentage (A(%))5 minutes (300 sec)99.7997.562.232.285810 minutes (600 seconds)98.510.950.973815 minutes (900 seconds)97.790.230.235820 minutes (1200 seconds)97.13-0.43-0.440825 minutes (1500 seconds)96.30-1.26-1.291530 minutes (1800 seconds)95.83-1.73-1.7733Comparative example 4 hours Weight retention rate (a) Average value (b) Deviation (ab) Deviation percentage (A(%))5 minutes (300 sec)98.6396.801.831.890510 minutes (600 seconds)97.460.660.681815 minutes (900 seconds)97.010.210.216920 minutes (1200 seconds)96.58-0.22-0.227325 minutes (1500 seconds)96.12-0.68-0.702530 minutes (1800 seconds)94.97-1.83-1.8905Comparative example 5 hours Weight retention rate (a) Average value (b) Deviation (ab) Deviation percentage (A(%))5 minutes (300 sec)97.5295.961.561.625710 minutes (600 seconds)96.981.021.062915 minutes (900 seconds)96.110.150.156320 minutes (1200 seconds)95.62-0.34-0.354325 minutes (1500 seconds)95.13-0.83-0.864930 minutes (1800 seconds)94.38-1.58-1.6465.

[0281] As shown in Tables 4 and 5 above, the aerogel composites according to the present invention (Examples 1 to 5) showed a small weight loss rate of the specimen after 5 minutes at a high temperature of 350°C, and almost no weight change over time. Even after a long time of 60 minutes, the weight retention rate was 97 wt% or more, and the weight loss rate was only less than 3 wt%. In addition, it was observed that the weight retention rate of the aerogel composite according to the present invention was maintained almost constant over a relatively short time of 5 minutes to a relatively long time of 30 minutes. However, the aerogel composites of Comparative Examples 1 to 5 showed a pattern of continuous weight loss during the 60 minutes of analysis, and it was confirmed that the weight loss rate was also significantly greater than that of the examples. In addition, it was observed that the weight of the aerogel composites of Comparative Examples 1 to 5 fluctuated greatly from 5 minutes to 30 minutes.

[0282]

[0283] [Experimental Example 4] Surface and cross-sectional water repellency evaluation

[0284] The following experiments were conducted to evaluate the surface and internal hydrophobicity of the aerogel composite manufactured according to the present invention.

[0285] 1. Surface water repellency measurement

[0286] First, 10 cm X 10 cm sized specimens (with a thickness of approximately 4 mm, which is the thickness of the aerogel composite) were obtained from each of the aerogel composites of Examples 1 to 5 and Comparative Examples 1 to 5, and then floated on distilled water at a temperature of 21±2 ℃, and then a 6.4 mm mesh screen was sunk to 127 mm below the water surface (impregnation). After 15 minutes, the mesh screen was removed, and when the specimen floated, the specimen was picked up with a clamp and hung vertically for 60±5 seconds. Thereafter, the weight of the specimens before and after impregnation was measured, and the result was calculated according to the following Equation 4, which was expressed as the surface water repellency. A lower surface water repellency value indicates a better hydrophobicity of the silica aerogel composite surface.

[0287] [Formula 4]

[0288] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0289] 2. Measurement of cross-sectional water repellency

[0290] The cross-sectional water repellency was measured using the same method as the surface water repellency by cutting a 10 cm X 10 cm sized specimen into a 1 cm X 1 cm sized specimen (with a thickness of approximately 4 mm, which is the thickness of the aerogel composite). However, considering the size of the specimen, the cross-sectional water repellency was measured by preparing 5 specimens for each example or comparative example, repeating the same experiment for each specimen, and then expressing the average value. At this time, the average value was rounded to the third decimal place and expressed to the second decimal place. Here, the lower the cross-sectional water repellency value, the better the hydrophobicity of the interior of the silica aerogel composite.

[0291] Surface water repellency (%) Cross-section water repellency (%) Example 11.18 0.76 Example 20.75 0.51 Example 33.54 1.13 Example 43.21 1.15 Example 53.61.13 Comparative Example 14.89 3.75 Comparative Example 24.45 2.73 Comparative Example 35.64 3.16 Comparative Example 49.51 5.51 Comparative Example 511.016.13

[0292] As shown in Table 6 above, the surface water repellency of the aerogel composites of Examples 1 to 5 according to the present invention is low at approximately 4 wt% or less, and the cross-sectional water repellency is also very low at 1.5 wt% or less. Through this, it was found that the aerogel composite according to the present invention has high surface and internal hydrophobicity and excellent water repellency. On the other hand, the surface water repellency of the aerogel composites of Comparative Examples 1 to 5 is at a level exceeding 4 wt%, and the cross-sectional water repellency is very low at a minimum of 2.73 wt% and a maximum of 6.13 wt%, and in particular, it was found that the hydrophobicity is low inside the aerogel composite.

[0293]

[0294] [Experimental Example 5] Insulation Evaluation

[0295] In order to evaluate the room temperature thermal conductivity of the aerogel composite manufactured according to the present invention, the room temperature thermal conductivity of the aerogel composite of 60 cm X 12 cm size manufactured in each example and comparative example was measured using the HFM436 equipment of Netzsch Corporation, and the results are shown in Table 7 below.

[0296] In addition, in order to evaluate the thermal conductivity at high temperatures, the aerogel composites manufactured in the above examples and comparative examples were subjected to GHP (Guarded Hot Plate) high-temperature thermal conductivity measurements at a temperature of approximately 150°C using NETZSCH's GHP 456 equipment, and the results are shown in Table 7 below.

[0297] ClassificationRoom temperature thermal conductivity(mW / mK)High temperature thermal conductivity(mW / mK)Example 120.823.8Example 220.523.5Example 318.521.3Example 417.921.1Example 518.722.0Comparative Example 121.124.7Comparative Example 220.924.1Comparative Example 321.324.2Comparative Example 423.226.2Comparative Example 525.929.7

[0298] As shown in Table 7 above, it was found that the aerogel composites of Examples 1 to 5 according to the present invention had superior insulation properties at both room temperature and high temperature compared to the aerogel composites of Comparative Examples 1 to 5.

[0299]

[0300] [Example 6] Manufacturing of insulating material

[0301] An insulating member was manufactured by attaching ALKYN-1505(C) product from ALKYNES, in which a 25 ㎛ thick acrylic adhesive was applied to one side of a 25 ㎛ thick PET film, to both sides of the aerogel composite manufactured in Examples 1 to 5 above.

[0302]

[0303] [Example 7] Manufacturing of insulating material

[0304] An insulating member was manufactured by attaching ALKYN-4005 (FR) product from ALKYNES, to which a 25 μm thick acrylic adhesive was applied on one side of a 25 μm thick flame-retardant PET film, to both sides of the aerogel composite manufactured in Examples 1 to 5 above.

[0305]

[0306] [Example 8] Manufacturing of insulating material

[0307] On both sides of the aerogel composite manufactured in Examples 1 to 5, a polyester film having a thickness of 7 μm and a PET film having a thickness of 12 μm were sequentially laminated, and ALKYNES' ALKYN-4004D (PS) product with a 25 μm thick acrylic adhesive was attached to the other side of the polyester film to manufacture an insulating member.

[0308]

[0309] While specific aspects of the present invention have been described in detail above, it should be apparent to those skilled in the art that these specific descriptions are merely preferred implementation examples and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

[0310] The present invention relates to an aerogel composite and its use as an insulating material.

Claims

1. A fiber substrate comprising a plurality of discrete fibers and voids between the fibers; and An aerogel composite comprising a silica aerogel having a network structure including one or more pores and a plurality of aerogel particles positioned on the fibers or in the voids between the fibers, The weight retention rate measured after heating the above aerogel composite at a temperature of 350 ℃ for 60 minutes is 96% or more, The weight retention measured after heating the above aerogel composite at a temperature of 350 ℃ for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes satisfies the following equation 2: [Formula 2] A(%) = {(Weight retention rate measured after heating for x minutes (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100 In the above equation 2, the x minutes are 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, The weight retention (a) measured after heating for the above x minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for x minutes, relative to the weight of the aerogel composite before heating at 350°C. The average value (b) of the weight retention rates after the above heating means the average value of the weight retention rates obtained after heating the aerogel composite at a temperature of 350 ℃ for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. The above A is a real number between -1.0 and +1.

0.

2. In paragraph 1, The above A is an aerogel composite, which is a real number between -0.80 and +0.

80.

3. In paragraph 1, An aerogel composite, wherein the weight retention (a) of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes and 30 minutes, respectively, satisfies Equation 2.

4. In paragraph 1, An aerogel composite, wherein the weight retention (a) of the aerogel composite measured after heating the aerogel composite at 350°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes satisfies Equation 2.

5. In paragraph 1, An aerogel composite having a weight retention of 97% or more measured after heating the aerogel composite at a temperature of 350°C for 30 minutes.

6. In paragraph 1, The absolute value (B) of the change in the weight retention rate of the aerogel composite per unit time when the aerogel composite is heated at a temperature of 350°C for 5 minutes and 60 minutes satisfies the following equation 3: [Formula 3] B = |{(Weight retention measured after heating for y minutes) - (Weight retention measured after heating for z minutes)} / (y - z)| In the above equation 3, y is 5 minutes, z is 60 minutes, The weight retention measured after heating for the above y minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for y minutes, relative to the weight of the aerogel composite before heating at 350°C. The weight retention measured after heating for the above z minutes is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 350°C for z minutes, relative to the weight of the aerogel composite before heating at 350°C. The above B is 1.0 X 10 -3 7.0 X 10 -2 It is a mistake.

7. In paragraph 1, An aerogel composite, wherein the total volume ratio of the fibers per unit volume of the aerogel composite is 2 to 12%, and the volume ratio of the voids between the aerogel including pores and the discrete fibers in the aerogel composite is 88 to 98%.

8. In paragraph 7, An aerogel composite, wherein the total volume ratio of the fibers per unit volume of the aerogel composite is 5 to 10%, and the volume ratio of the voids between the aerogel including pores and the discrete fibers in the aerogel composite is 90 to 95%.

9. In paragraph 1, An aerogel composite, wherein the fiber substrate and the aerogel in the aerogel composite are included in a weight ratio of 1:0.4 to 2.

10. In paragraph 1, An aerogel composite, wherein the aerogel comprises silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

11. In paragraph 1, The above aerogel composite is an aerogel composite having a moisture impregnation rate (weight%) of 4 weight% or less for a specimen of 100 mm X 100 mm size represented by the following formula 4: [Formula 4] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100 In the above equation 4, the weight of the specimen after impregnation means the weight of the aerogel composite specimen after being impregnated in distilled water at 21±2°C for 15 minutes.

12. In paragraph 1, The above aerogel composite is an aerogel composite having a moisture impregnation rate (weight%) of 2 weight% or less for a specimen of 10 mm X 10 mm size represented by the following formula 4: [Formula 4] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100 In the above equation 4, the weight of the specimen after impregnation means the weight of the aerogel composite specimen after being impregnated in distilled water at 21±2°C for 15 minutes.

13. An insulating member comprising an aerogel composite according to any one of claims 1 to 12.

14. In paragraph 13, An insulating member, wherein the insulating member further includes a support member positioned on at least one of the upper and lower surfaces of the aerogel composite.

15. A battery module comprising a module case having an internal space, one or more battery cells positioned in the internal space, and an aerogel composite according to any one of claims 1 to 12.

16. A battery pack comprising the battery module of clause 15.

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