Aerogel composite

Abstract

The present invention relates to an aerogel composite having excellent thermal stability and flame retardancy even when exposed to a high-temperature environment for a long time.

Description

Aerogel composites

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

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0114837, filed August 30, 2023, and U.S. Patent Application No. 18 / 524,301, filed November 30, 2023, 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, some of the components within the aerogel may decompose or be lost, which may cause problems such as the collapse of the aerogel structure and a significant deterioration in physical properties such as insulation and flame retardancy. Such problems may also occur when aerogel blankets are applied to battery modules. Therefore, from a safety perspective, it is required that the aerogel blankets have excellent thermal stability and maintain high flame retardancy by ensuring that the degree of decomposition or loss of the 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 and flame retardancy 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, an aerogel composite comprising a fiber substrate and an aerogel including one or more pores, wherein the weight retention measured after heating the aerogel composite at a temperature of 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes can satisfy the following equation 2.

[0012] [Formula 2]

[0013] A = {(Weight retention rate measured after heating for x hours (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0014] In the above equation 2, the x time is 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes, the weight retention rate (a) measured after heating for the x time is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300° C. for x time, relative to the weight of the aerogel composite before heating, 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 300° C. for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, and the above A is a real number of -0.50 to +0.50.

[0015] The weight retention measured after heating the above aerogel composite at a temperature of 300°C for 60 minutes may be 97 wt% or more.

[0016] When the above aerogel composite is heated at a temperature of 300°C for 5 minutes and 60 minutes, the absolute value (B) of the change in weight retention rate of the aerogel composite per unit time can satisfy the following equation 3:

[0017] [Formula 3]

[0018] B = |{(Weight retention measured after heating for y hours) - (Weight retention measured after heating for z hours)} / (y - z)|

[0019] In the above formula 3, the y is 5 minutes, the z is 60 minutes, the weight retention measured after heating for the y time is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300 ℃ for y hours, compared to the weight of the aerogel composite before heating, the weight retention measured after heating for the z time is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300 ℃ for z hours, compared to the weight of the aerogel composite before heating, and the B is 1.0 X 10 -3 4.0 X 10 -2 It could be a mistake.

[0020] When the above aerogel composite is heated at a temperature of 300 ℃ for 5 minutes and 30 minutes, the absolute value (B) of the change in the weight retention rate of the aerogel composite per unit time can satisfy the above equation 3. In that case, in the above equation 3, y is 5 minutes, z is 30 minutes, and the above B is 1.0 X 10 -3 3.0 X 10 -2 It could be a mistake.

[0021] The moisture impregnation rate of the above aerogel composite, expressed by the following Equation 4, may be 5 wt% or less.

[0022] [Formula 4]

[0023] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0024] 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.

[0025] The average sustained heat of combustion (Qsb) measured according to ISO 5658-2 standard in the above aerogel composite is 0.5 MJ / m 2 It could be strange.

[0026] The critical heat flux (CHF) during digestion measured according to ISO 5658-2 standard in the above aerogel composite is 25 kW / m 2 It could be strange.

[0027] The thermal conductivity of the above aerogel composite at room temperature (23±5 ℃) may be 15.0 mW / mK or less.

[0028] The thermal conductivity of the above aerogel composite at 150°C may be 25.0 mW / mK or less.

[0029] When the above aerogel composite is heated at a temperature of 150°C for 60 minutes, the amount of ammonia gas generated per unit weight of the aerogel composite may be 10 to 70 μg / g.

[0030] According to another embodiment of the present invention, there is provided an insulating member comprising an aerogel composite provided by the present invention.

[0031] 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.

[0032] The aerogel composite provided by the present invention exhibits excellent thermal stability, with minimal aerogel component decomposition or loss even when exposed to high temperatures for extended periods of time, and minimal weight change over time at high temperatures. Furthermore, the aerogel composite provided by the present invention exhibits excellent flame retardancy even without the addition of a separate flame retardant during its manufacture. Therefore, the aerogel composite according to the present invention can maintain excellent thermal insulation properties even in high-temperature environments.

[0033] According to one embodiment of the present invention, an aerogel composite comprising a fiber substrate; and an aerogel including one or more pores,

[0034] The weight retention measured after heating the above aerogel composite at a temperature of 300 ℃ for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and 30 minutes satisfies the following equation 2,

[0035] The aerogel composite is characterized in that the weight retention measured after heating the aerogel composite at a temperature of 300°C for 60 minutes is 97 wt% or more.

[0036] [Formula 2]

[0037] A = {(Weight retention rate measured after heating for x hours (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0038] In the above equation 2,

[0039] The above x time is 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, and the weight retention rate (a) measured after heating for the x time is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300°C for x time, relative to the weight of the aerogel composite at 300°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 300°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and 30 minutes, and the above A is a real number of -0.50 to +0.50.

[0040] When the above aerogel composite is heated at a temperature of 300°C for 5 minutes and 60 minutes, the absolute value (B) of the change in weight retention rate of the aerogel composite per unit time can satisfy the following equation 3:

[0041] [Formula 3]

[0042] B = |{(Weight retention measured after heating for y hours) - (Weight retention measured after heating for z hours)} / (y - z)|

[0043] In the above formula 3, the y is 5 minutes, the z is 60 minutes, the weight retention measured after heating for the y time is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300 ℃ for y hours, compared to the weight of the aerogel composite before heating, the weight retention measured after heating for the z time is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300 ℃ for z hours, compared to the weight of the aerogel composite before heating, and the B is 1.0 X 10 -3 4.0 X 10 -2 It is a mistake.

[0044] When the above aerogel composite is heated at a temperature of 300 ℃ for 5 minutes and 30 minutes, the absolute value (B) of the change in the weight retention rate of the aerogel composite per unit time can satisfy the above equation 3. In that case, in the above equation 3, y is 5 minutes, z is 30 minutes, and the above B is 1.0 X 10 -3 3.0 X 10 -2 It is a mistake.

[0045] The moisture impregnation rate of the above aerogel composite, expressed by the following Equation 4, may be 5 wt% or less. The moisture impregnation rate may be 2 wt% or less.

[0046] [Formula 4]

[0047] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0048] 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.

[0049] The weight retention rate measured after heating the above aerogel composite at a temperature of 300°C for 30 minutes may be 97 wt% or more.

[0050] The average sustained heat of combustion (Qsb) measured according to ISO 5658-2 standard in the above aerogel composite is 0.5 MJ / m 2 It could be strange.

[0051] The critical heat flux (CHF) during digestion measured according to ISO 5658-2 standard in the above aerogel composite is 25 kW / m 2 It could be strange.

[0052] The thermal conductivity of the above aerogel composite at room temperature (23±5 ℃) may be 15.0 mW / mK or less.

[0053] The thermal conductivity of the above aerogel composite at 150°C may be 25.0 mW / mK or less.

[0054] When the aerogel composite is heated at a temperature of 150° C. for 60 minutes, the amount of ammonia gas generated per unit weight of the aerogel composite may be 10 to 70 μg / g, or may be 10 to 50 μg / g. The aerogel composite may include ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) particles on the aerogel or within pores within the aerogel so that the amount of ammonia gas generated per unit weight of the aerogel composite when heated at a temperature of 150° C. for 60 minutes satisfies the above range.

[0055] According to another embodiment of the present invention, there is provided an insulating member comprising an aerogel composite provided by the present invention.

[0056] 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.

[0057] 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.

[0058]

[0059] 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.

[0060] The above “aerogel” includes a three-dimensional network structure in which a plurality of aerogel particles having a size of approximately 2 to 20 nm are aggregated or bonded to form a plurality of open pores.

[0061] The aerogel may be an inorganic silica aerogel formed from a silicon alkoxide compound or water glass as a precursor. The aerogel may be composed of silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof. The aerogel may have at least a portion of the SiO2 on the surface of the SiO2 network having a bonding structure of Si-O-SiO2(CH3), Si-O-SiO(CH3)2, or Si-O-Si(CH3)3. The manufacturing process of the aerogel is described in detail below.

[0062] The above "aerogel particles" are particles in the form of individual solid units that constitute the aerogel, and may be powders, beads, fine particles, granules, pellets, aggregates, fibers, flakes, etc., and the shapes may be spherical, hemispherical, circular, semicircular, polygonal, cubic, rod-shaped, polyhedral, irregular, etc. In the present invention, the aerogel particles may have an average particle diameter of about 10 to 2000 nm, 10 to 1500 nm, or 10 to 1000 nm, but is not limited thereto. In the present invention, 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.

[0063] 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. In the present invention, the aerogel may include mesopores 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 of the present invention may include mesopores. In one specific example, the aerogel of the present invention may include mesopores and micropores. In the present invention, 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).

[0064] The porosity of the above aerogel may be about 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.

[0065] 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 discrete fibers within the substrate. Examples of the substrate in the present invention 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 be formed with surface roughness or patterned.

[0066] 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-Fiber® 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® (manufactured by DuPont), Dyneema® (manufactured by DSM), Spectra® (manufactured by Honeywell), other polypropylene fibers such as Typar®, Xavan® (both manufactured by DuPont), fluoropolymers such as PTFE under the Teflon® brand name (manufactured by DuPont), Gore-tex® (manufactured by WL GORE), silicon carbide fibers such as NICALCON (manufactured by COI Ceramics), ceramic fibers such as NEXTEL (manufactured by 3M), acrylic polymers, wool, silk, hemp, leather, suede fibers, PBO fibers Zylon® (manufactured by Teflon), liquid crystal materials such as VECTAN (manufactured by Hoekst), 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 spaces or voids into which aerogels can be easily inserted may be used without limitation. there is.

[0067] The thickness of the above fiber substrate may be, but is not limited to, 0.5 to 20 mm.

[0068] The thickness of the above aerogel composite may be, but is not limited to, 0.5 to 20 mm.

[0069] In the above aerogel composite, ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) particles may be included on the aerogel or within the pores within the aerogel. When the aerogel composite provided in the present invention is exposed to a high temperature of 150°C or higher, the ammonium bicarbonate or ammonium carbonate present on the aerogel is thermally decomposed into ammonia gas, carbon dioxide, and water vapor. Therefore, the amount of ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) included in the aerogel can be confirmed by measuring the amount of ammonia gas generated at a high temperature of 150°C or higher.

[0070] The aerogel composite provided in the present invention can have excellent flame retardancy without adding a separate flame retardant during the manufacturing process by containing ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) particles in a specific range of contents.

[0071] In order to secure the above-mentioned effect, it is preferable that the aerogel composite contains ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) so that ammonia gas generated from the aerogel composite is generated in the amount below when heated at a temperature of 150°C for 60 minutes. In detail, the aerogel composite provided in the present invention may generate ammonia gas per unit weight of the aerogel composite when heated at a temperature of 150° C. for 60 minutes, which may be about 10 μg / g or more, 15 μg / g or more, 20 μg / g or more, 25 μg / g or more, 30 μg / g or more, or 35 μg / g or more, and may be 90 μg / g or less, 80 μg / g or less, 70 μg / g or less, 60 μg / g or less, 50 μg / g or less, 40 μg / g or less, 30 μg / g or less, 20 μg / g or less, or 15 μg / g or less. Preferably, the amount of ammonia gas generated per unit weight of the aerogel composite may be 10 to 90 μg / g, 10 to 80 μg / g, 10 to 70 μg / g, 10 to 60 μg / g, 10 to 50 μg / g, 10 to 40 μg / g, 15 to 40 μg / g, 20 to 40 μg / g, 30 to 40 μg / g or 35 to 40 μg / g. The amount of ammonia gas generated per unit weight of the aerogel composite may be about 10 to 70 μg / g. The amount of ammonia gas generated per unit weight of the aerogel composite may be about 10 to 60 μg / g. The amount of ammonia gas generated per unit weight of the aerogel composite may be about 10 to 50 μg / g.

[0072] When the above aerogel composite comprises ammonium bicarbonate (NH4HCO3), ammonium carbonate ((NH4)2CO3) or a mixture thereof, they are present in an amount of about 30 ppm or more, 40 ppm or more, 50 ppm or more, 55 ppm or more, 60 ppm or more, 65 ppm or more, 70 ppm or more, 75 ppm or more, 80 ppm or more, 85 ppm or more, 90 ppm or more, 95 ppm or more, 100 ppm or more, 105 ppm or more, 110 ppm or more, 115 ppm or more, 120 ppm or more, 125 ppm or more, 130 ppm or more, 135 ppm or more, 140 ppm or more, 145 ppm or more, 150 ppm or more, 155 ppm or more, 160 ppm or more, 165 ppm or more, 170 It may be greater than or equal to 175 ppm, and less than or equal to 300 ppm, less than or equal to 280 ppm, less than or equal to 260 ppm, less than or equal to 240 ppm, less than or equal to 220 ppm, less than or equal to 200 ppm, less than or equal to 190 ppm, less than or equal to 180 ppm, less than or equal to 170 ppm, less than or equal to 160 ppm, less than or equal to 150 ppm, less than or equal to 140 ppm, less than or equal to 130 ppm, less than or equal to 120 ppm, less than or equal to 110 ppm, less than or equal to 100 ppm, less than or equal to 90 ppm, less than or equal to 80 ppm, less than or equal to 70 ppm, or less than or equal to 60 ppm. Preferably, ammonium bicarbonate (NH4HCO3), ammonium carbonate ((NH4)2CO3) or a mixture thereof may be included in the aerogel composite in an amount of about 30 to 300 ppm, about 40 to 300 ppm, about 50 to 300 ppm, about 50 to 280 ppm, about 50 to 260 ppm, about 50 to 240 ppm, or about 50 to 220 ppm. The ammonium bicarbonate (NH4HCO3), ammonium carbonate ((NH4)2CO3) or a mixture thereof may be included in the aerogel composite in an amount of about 50 to 280 ppm.The ammonium bicarbonate (NH4HCO3), ammonium carbonate ((NH4)2CO3) or a mixture thereof may be included in the aerogel composite at about 50 to 260 ppm. The ammonium bicarbonate (NH4HCO3), ammonium carbonate ((NH4)2CO3) or a mixture thereof may be included in the aerogel composite at about 50 to 240 ppm. The ammonium bicarbonate (NH4HCO3), ammonium carbonate ((NH4)2CO3) or a mixture thereof may be included in the aerogel composite at about 50 to 220 ppm.

[0073] When the above aerogel composite contains ammonium bicarbonate (NH4HCO3), the ammonium bicarbonate (NH4HCO3) is present in the aerogel composite at about 30 ppm or more, 40 ppm or more, 50 ppm or more, 55 ppm or more, 60 ppm or more, 65 ppm or more, 70 ppm or more, 75 ppm or more, 80 ppm or more, 85 ppm or more, 90 ppm or more, 95 ppm or more, 100 ppm or more, 105 ppm or more, 110 ppm or more, 115 ppm or more, 120 ppm or more, 125 ppm or more, 130 ppm or more, 135 ppm or more, 140 ppm or more, 145 ppm or more, 150 ppm or more, 155 ppm or more, 160 ppm or more, 165 ppm or more, It may be 170 ppm or more, or 175 ppm or more, and 300 ppm or less, 280 ppm or less, 260 ppm or less, 240 ppm or less, 220 ppm or less, 200 ppm or less, 190 ppm or less, 180 ppm or less, 170 ppm or less, 160 ppm or less, 150 ppm or less, 140 ppm or less, 130 ppm or less, 120 ppm or less, 110 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, or 60 ppm or less.Preferably, ammonium bicarbonate (NH4HCO3) is present in the aerogel composite at about 30 to 300 ppm, about 40 to 300 ppm, about 40 to 200 ppm, about 50 to 200 ppm, about 40 to 190 ppm, about 50 to 190 ppm, about 40 to 180 ppm, about 50 to 180 ppm, about 60 to 180 ppm, about 70 to 180 ppm, about 80 to 180 ppm, about 90 to 180 ppm, about 100 to 180 ppm, about 110 to 180 ppm, about 20 to 180 ppm, about 130 to 180 ppm, about 140 to 180 ppm, about 150 to 180 ppm, about It can be included in an amount of 160 to 180 ppm or about 170 to 180 ppm. The ammonium bicarbonate (NH4HCO3) can be included in the aerogel composite in an amount of about 40 to 300 ppm. The ammonium bicarbonate (NH4HCO3) can be included in the aerogel composite in an amount of about 40 to 200 ppm. The ammonium bicarbonate (NH4HCO3) can be included in the aerogel composite in an amount of about 50 to 200 ppm. The ammonium bicarbonate (NH4HCO3) can be included in the aerogel composite in an amount of about 40 to 190 ppm.

[0074] When the above aerogel composite includes ammonium carbonate ((NH4)2CO3), the ammonium carbonate ((NH4)2CO3) may be present in the aerogel composite at about 30 ppm or more, 40 ppm or more, 50 ppm or more, 60 ppm or more, 70 ppm or more, 80 ppm or more, 90 ppm or more, 100 ppm or more, 110 ppm or more, 120 ppm or more, 130 ppm or more, 140 ppm or more, 150 ppm or more, 160 ppm or more, 170 ppm or more, 180 ppm or more, 190 ppm or more, 200 ppm or more, or 210 ppm or more, and 300 ppm or less, 280 ppm or less, 260 ppm or less, 240 ppm or less, 220 ppm or less, 200 ppm or less, It can be 190 ppm or less, 180 ppm or less, 170 ppm or less, 160 ppm or less, 150 ppm or less, 140 ppm or less, 130 ppm or less, 120 ppm or less, 110 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, or 60 ppm or less. Preferably, ammonium carbonate ((NH4)2CO3) can be included in the aerogel composite in an amount of about 30 to 300 ppm, about 40 to 300 ppm, about 50 to 300 ppm, about 50 to 280 ppm, about 50 to 260 ppm, about 50 to 240 ppm, about 50 to 220 ppm, about 60 to 220 ppm, about 70 to 220 ppm, about 80 to 220 ppm, about 90 to 220 ppm, about 100 to 220 ppm, about 120 to 220 ppm, about 140 to 220 ppm, about 160 to 220 ppm, about 180 to 220 ppm, or about 200 to 220 ppm. The above ammonium carbonate ((NH4)2CO3) may be included in the aerogel composite in an amount of about 50 to 300 ppm.The ammonium carbonate ((NH4)2CO3) may be included in the aerogel composite in an amount of about 50 to 280 ppm. The ammonium carbonate ((NH4)2CO3) may be included in the aerogel composite in an amount of about 50 to 260 ppm. The ammonium carbonate ((NH4)2CO3) may be included in the aerogel composite in an amount of about 50 to 240 ppm.

[0075] Here, the content of the above-mentioned ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) may correspond to the amount of ammonia gas generated as described above.

[0076] If the aerogel composite contains ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) in a small amount that falls below the above-mentioned content range, it is difficult to secure sufficient flame retardancy, and if it contains ammonium bicarbonate (NH4)2CO3) in a small amount that falls below the above-mentioned content range, water repellency may be low and thermal stability may be reduced.

[0077] The amount of ammonia gas generated above is 1 X 1 cm 2 The aerogel composite specimen of the size can be measured by heating it at a temperature of 150 ℃ for 60 minutes and then using a headspace-gas chromatography (GC) / nitrogen chemiluminescence detector (NCD), but is not limited thereto. In addition, in the case of the above quantitative analysis, calibration can be performed by one-point calibration using a single standard product or five-point calibration through calibration curve creation without creating a separate calibration curve, and for example, one-point calibration can be performed based on a value corresponding to NH3, 14 ㎍, but is not limited thereto.

[0078] In addition, the ammonia gas generation amount may be obtained by randomly obtaining a total of five square specimens each having a size of 1 cm X 1 cm from the aerogel composite, and calculating the average value of the ammonia generation amount (㎍ / g) per unit weight of the specimens obtained from each specimen. At this time, the five specimens may be obtained by positioning a location 10 cm apart from each corner of the aerogel composite manufactured in a rectangular shape (for example, 12 cm X 60 cm in size, but is not limited thereto) at the exact center of the specimen, thereby obtaining four specimens, and positioning the exact center of the aerogel composite at the exact center of the specimen, thereby obtaining one specimen.

[0079] In addition, the aerogel composite has a small weight loss and high hydrophobicity, so that it has excellent thermal stability at high temperatures, as ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) is vaporized first at a high temperature of 150°C or higher. Specifically, even when the aerogel composite is exposed to a high temperature, particularly 300°C, for a long period of time, the weight change rate of the aerogel composite is small and maintained constant within a specific range, so that the insulating performance can be maintained at an excellent level without significant degradation.

[0080] The above "weight retention rate" is, as shown in Equation 1 below, the ratio of the weight measured after heating the aerogel composite at a temperature of 150°C or higher, preferably 300°C, for a predetermined period of time to the weight of the aerogel composite before heating, expressed as a percentage. Here, the predetermined period of 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. The predetermined time may be from 5 minutes to 30 minutes. The predetermined time may be, but is not limited to, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes.

[0081] [Formula 1]

[0082] Weight retention of aerogel composite after heating (wt%) = {(Weight of aerogel composite after heating) / (Weight of aerogel composite before heating)} X 100

[0083] The weight retention measured after heating the above aerogel composite at a temperature of 300°C for any one of a continuous period of time selected from 5 minutes to 30 minutes may satisfy the following equation 2:

[0084] [Formula 2]

[0085] A (%) = {(Weight retention rate measured after heating for x hours (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0086] In the above formula 2, the "x time" means any one of a continuous duration of 5 minutes to 30 minutes, and the unit of time may be 'minute'. The x time may be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes, but is not limited thereto.

[0087] In addition, the above “weight retention (a) measured after heating for x hours” means the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300°C for x hours, compared to the weight of the aerogel composite before heating at 300°C according to the above equation 1.

[0088] 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 300°C for at least two consecutive times selected from 5 minutes to 30 minutes. It may mean an average value of weight retention rates of the aerogel composite obtained after heating the aerogel composite at 300°C for at least two consecutive times 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.

[0089] The above A is - 0.50 to + 0.50, - 0.40 to + 0.40, - 0.35 to + 0.35, - 0.30 to + 0.30, - 0.29 to + 0.29, - 0.28 to + 0.28, - 0.27 to + 0.27, - 0.26 to + 0.26, - 0.25 to + 0.25, - 0.24 to + 0.24, - 0.23 to + 0.23, - 0.22 to + 0.22, - 0.21 to + 0.21, - 0.20 to + 0.20, - 0.19 to + 0.19, - 0.18 to + 0.18, - 0.17 to + 0.17, - A may be a real number in the range of 0.16 to + 0.16, - 0.15 to + 0.15, - 0.14 to + 0.14, - 0.13 to + 0.13, - 0.12 to + 0.12, - 0.11 to + 0.11, or - 0.10 to + 0.10. A may be a real number in the range of - 0.40 to + 0.40. A may be a real number in the range of - 0.35 to + 0.35. A may be a real number in the range of - 0.30 to + 0.30. A may be a real number in the range of - 0.25 to + 0.25.

[0090] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 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 300°C for at least two times selected from among 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0091] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for 5 minutes or 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 300°C for at least two times selected from among 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. The above A may be a real number from -0.35 to +0.35. The above A may be a real number from -0.30 to +0.30. The above A may be a real number from -0.25 to +0.25.

[0092] The weight retention ratio of the aerogel composite measured after heating the aerogel composite at 300°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 300°C for at least two times selected from among 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. The above A may be a real number of -0.30 to +0.30. The above A may be a real number of -0.25 to +0.25.

[0093] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for 5 minutes may satisfy the above equation 2. At this time, 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 300°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. The above A may be a real number from -0.35 to +0.35. The above A may be a real number from -0.30 to +0.30. The above A may be a real number from -0.25 to +0.25. The above A may be a real number from 0 to +0.35. The above A may be a real number from 0 to +0.30. The above A may be a real number from 0 to +0.25.

[0094] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°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 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. The above A may be a real number from -0.10 to +0.10. The above A may be a real number from 0 to +0.15.

[0095] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for 15 minutes may satisfy the above equation 2. At this time, 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 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. The above A may be a real number of -0.10 to +0.10. The above A may be a real number of -0.05 to +0.05.

[0096] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for 20 minutes may satisfy the above equation 2. At this time, 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 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. The above A may be a real number of -0.10 to +0.10. The above A may be a real number of -0.10 to 0.

[0097] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for 25 minutes may satisfy the above equation 2. At this time, 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 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. The above A may be a real number from -0.20 to +0.20. The above A may be a real number from -0.15 to +0.15. The above A may be a real number from -0.20 to 0. The above A may be a real number from -0.15 to 0.

[0098] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°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 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively.

[0099] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for 30 minutes may satisfy the above equation 2. At this time, 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 300°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. The above A may be a real number from -0.30 to +0.30. The above A may be a real number from -0.20 to +0.20. The above A may be a real number from -0.15 to +0.15. The above A may be a real number from -0.30 to 0. The above A may be a real number from -0.20 to 0. The above A may be a real number from -0.15 to 0.

[0100] The weight retention of the aerogel composite measured after heating the aerogel composite at 300°C for 5 minutes and 30 minutes, respectively, may satisfy 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 300°C for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes, respectively. The above A may be a real number from -0.50 to +0.50. The above A may be a real number from -0.40 to +0.40. The above A may be a real number from -0.35 to +0.35. The above A may be a real number from -0.30 to +0.30. The above A may be a real number from -0.20 to 0. The above A can be a real number between -0.25 and +0.25.

[0101] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes may satisfy 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 300°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0102] The weight retention rate of the aerogel composite measured after heating the aerogel composite at 300°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes may satisfy 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 300°C for each of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. The above A may be a real number of -0.50 to +0.50. The above A may be a real number of -0.40 to +0.40. The above A may be a real number of -0.35 to +0.35. The above A may be a real number of -0.30 to +0.30. The above A can be a real number between -0.25 and +0.25.

[0103] In addition, when the aerogel composite is heated to a temperature of 300°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.

[0104] [Formula 3]

[0105] B = |{(Weight retention measured after heating for y hours) - (Weight retention measured after heating for z hours)} / (y - z)|

[0106] In the above equation 3, y and z are time values ​​independently selected from a continuous time of 5 to 60 minutes, and are different values. In this case, the unit of time may be 'minute'.

[0107] In addition, the above “weight retention measured after heating for y hours” and “weight retention measured after heating for z hours” mean the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300° C. for y hours or z hours, relative to the weight of the aerogel composite before heating according to the above Equation 1.

[0108] Also, the above B is 1.0 X 10 -3 5.0 X 10 -2 , 1.0 X 10 -3 4.5 X 10 -2 , 1.0 X 10 -3 4.0 X 10 -2 , 1.0 X 10 -3 3.5 X 10 -2 , 1.0 X 10 -3 3.0 X 10 -2 , 1.5 X 10 -3 3.0 X 10 -2 , 2.0 X 10 -3 3.0 X 10 -2 , 2.5 X 10 -3 3.0 X 10 -2 , 3.0 X 10 -3 3.0 X 10 -2 , 3.0 X 10 -3 2.5 X 10 -2 , 3.0 X 10 -3 2.0 X 10 -2 , 2.5 X 10 -3 2.0 X 10 -2 , 2.0 X 10 -3 2.0 X 10 -2 or 3.0 X 10 -3 2.0 X 10 -2It can be a real number within the range of . The above B is 1.0 X 10 -3 5.0 X 10 -2 may be a mistake. The above B is 1.0 X 10 -3 4.5 X 10 -2 may be a mistake. The above B is 1.0 X 10 -3 4.0 X 10 -2 It could be a mistake.

[0109] In the above equation 3, x may be 5 minutes and y may be 30 minutes; or x may be 30 minutes and y may be 5 minutes. In this case, B may be 1.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 1.5 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 2.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 2.5 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.5 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 3.5 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 4.0 X 10 -3 2.0 X 10 -2 It could be a mistake.

[0110] In the above equation 3, x may be 5 minutes and y may be 40 minutes; or x may be 40 minutes and y may be 5 minutes. In this case, B may be 1.0 X 10 -3 3.0 X 10 -2may be a mistake. The above B is 1.5 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 2.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 2.5 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.5 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 3.5 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 4.0 X 10 -3 2.0 X 10 -2 It could be a mistake.

[0111] In the above equation 3, x may be 5 minutes and y may be 50 minutes; or x may be 50 minutes and y may be 5 minutes. In this case, B is 2.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 2.5 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.5 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 3.5 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 4.0 X 10 -32.0 X 10 -2 may be a mistake. The above B is 4.5 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 4.0 X 10 -3 1.5 X 10 -2 may be a mistake. The above B is 4.5 X 10 -3 1.5 X 10 -2 It could be a mistake.

[0112] In the above equation 3, x may be 5 minutes and y may be 60 minutes; or x may be 60 minutes and y may be 5 minutes. In this case, B is 2.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 2.5 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 3.0 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.5 X 10 -2 may be a mistake. The above B is 3.0 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 3.5 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 4.0 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 4.5 X 10 -3 2.0 X 10 -2 may be a mistake. The above B is 4.0 X 10 -3 1.5 X 10 -2 may be a mistake. The above B is 4.5 X 10 -3 1.5 X 10 -2 It could be a mistake.

[0113] The above aerogel composite may have a weight retention of 97% or more, 98% or more, or 99% or more measured after heating for 30 minutes.

[0114] The above aerogel composite may have a weight retention of 96.5% or more, 97% or more, 98% or more, or 99% or more, measured after heating for 60 minutes.

[0115] In the above aerogel composite, the moisture impregnation rate (weight%) expressed by the following formula 4 may be 5 weight% or less, preferably 2 weight% or less.

[0116] [Formula 4]

[0117] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0118] In the above equation 4, the moisture impregnation rate can be calculated by floating a 100 mm x 100 mm sized aerogel composite specimen 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.

[0119] The average heat of combustion (Qsb; MJ / m) of the above aerogel composite 2 ) is 0.5 MJ / m 2 Ideally, 0.7 MJ / m 2 It may be ideal. Here, the average continuous heat of combustion may be measured according to the ISO 5658-2 standard.

[0120] Critical heat flux (CHF; kW / m) during digestion of the above aerogel composite 2 ) is 25 kW / m 2Ideally, 30 MJ / m 2 It may be ideal. Here, the critical heat flux during digestion may be measured according to the ISO 5658-2 standard.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] The above aerogel composite can generally be formed by 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 disclosure may include any aerogel formed by any related manufacturing method known to those skilled in the art.

[0126] Steps for preparing silica sol;

[0127] In the present invention, a silica sol can be prepared using a silica precursor composition.

[0128] The above silica precursor composition may include water and / or a polar organic solvent in the silica precursor.

[0129] 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. Among these, more specifically, in the case of the present invention, the silica precursor may be tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), or a mixture thereof.

[0130] 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.

[0131] In addition, the silica precursor may include pre-hydrolyzed TEOS (HTEOS). HTEOS is an ethyl silicate oligomer material having a wide 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.

[0132] The above silica precursor composition may further include a silicate containing a hydrophobic group. In the present invention, the silicate containing a hydrophobic group is not limited in type as long as it is an alkyl silane compound containing an alkyl group that induces hydrophobicity and a silane functional group that can react with the -Si-O- functional group of the wet gel. For example, the silicate containing a hydrophobic group may be at least one selected from the group consisting of methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDEOS), ethyltriethoxysilane (ETES), and phenyltriethoxysilane (PTES), but is not limited thereto.

[0133] In the present invention, ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) particles are included in the above-mentioned amount on the aerogel composite to be manufactured or in the pores within the aerogel, or ammonium ions (NH4) are generated in the above-mentioned amount per unit weight of the aerogel composite when the aerogel composite is heated at a temperature of 150°C for 60 minutes. +) may further be added in an amount of 0.1 to 2 wt%, 0.4 to 1.5 wt%, or 0.4 to 1 wt%. The ammonium ion (NH4 + ) may be used in an amount of 0.1 to 2 wt%, 0.4 to 1.5 wt%, or 0.4 to 1 wt%, but is not limited thereto.

[0134] The above ammonium ion (NH4 + ) in the above content range can be prepared by heating and refluxing hexamethyldisilazane (HMDS) in the presence of an organic solvent and an acid catalyst. The reflux conditions are not particularly limited and ammonium ion (NH4 + ) can be included without limitation as long as the content is performed so as to be included in the above range, but for example, reflux can be performed at 100 to 140°C, 100 to 130°C or 100 to 120°C for 10 minutes to 6 hours, 20 minutes to 6 hours, 30 minutes to 6 hours, 30 minutes to 5 hours or 30 minutes to 4 hours.

[0135] When the silica precursor composition includes a silicate containing the hydrophobic group, it may be included in a molar ratio of 9:1 to 1:9 with the tetraalkyl silicate (molar ratio of the hydrophobic group-containing silicate: tetraalkyl silicate). Within this range, the strength and insulating performance of the aerogel can be efficiently secured, while shrinkage during atmospheric pressure drying can be prevented, thereby preventing a decrease in the insulating performance.

[0136] 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 / m3 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 silica concentration in the present invention 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.

[0137] 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.

[0138] 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. In the present invention, the polar organic solvent may be, among these, a monohydric alcohol having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, butanol, etc., for example, ethanol, considering miscibility with water and aerogel.

[0139] 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.

[0140] In order to prepare a pre-hydrolyzed silica precursor when preparing the above silica precursor composition, the silica precursor and the organic solvent may be mixed in a weight ratio of 1:0.1 to 1.5, 1:0.5 to 1.5, or 1:0.5 to 1.2, but the present invention is not limited thereto.

[0141] In addition, in order to prepare a pre-hydrolyzed silica precursor when preparing the silica precursor composition, the silica precursor and water may be mixed in a molar ratio of 1:0.1 to 10, 1:1 to 8, or 1:2 to 6, but the present invention is not limited thereto.

[0142] In addition, when the silica precursor composition is manufactured, if a pre-hydrolyzed silica precursor (e.g., HTEOS) is included as the silica precursor, the pre-hydrolyzed silica precursor (e.g., HTEOS) and the organic solvent may be mixed in a weight ratio of 1:2 to 10, 1:3 to 8, or 1:3 to 6 to satisfy the silica concentration, but the present invention is not limited thereto.

[0143] 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.

[0144] 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.

[0145] The above base catalyst may be included in an amount such that the pH of the sol is 7 to 11. 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.

[0146] In order to prepare the above 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.

[0147] Additional 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, opacifying agents and additional flame retardants.

[0148] 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.

[0149] Gelation stage of silica sol

[0150] In the present invention, the silica sol can be gelated after impregnating the substrate with the silica sol.

[0151] 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.

[0152] The temperature of the silica sol in the reaction vessel may be 1 to 40° C., 20 to 40° C., 25 to 40° C., 30 to 40° C., or 35 to 45° C. 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.

[0153] 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 0.7 to 1:1, but is not limited thereto.

[0154] 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.

[0155] The above-mentioned catalyzed sol-impregnated substrate can be gelled on a moving element such as a conveyor belt.

[0156] The above "gelation" may refer to a sol-gel reaction, and the above "sol-gel reaction" may refer to forming a network structure 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.

[0157] The above gelation can be performed under an ambient temperature of 20 to 40°C, or 20 to 30°C, and the gelation time can 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.

[0158] Maturation stage of the gelled wet gel complex

[0159] 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.

[0160] 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.

[0161] 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.

[0162] The above maturation step can be carried out by leaving the mixture at a temperature of 30°C to 80°C, 40°C to 80°C, or 50°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours to strengthen the 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.

[0163] In addition, the above aging step may be performed firstly by leaving the mixture at 30°C to 80°C for 0.1 to 5 hours to strengthen the pore structure, and then secondly by aging the mixture at 30°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours in the presence of a solution in which a base catalyst is diluted in an organic solvent at a concentration of 1 to 10%.

[0164] 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.

[0165] Surface modification step of the matured wet gel composite

[0166] The present invention includes a surface modification step of hydrophobicizing the surface of a wet gel composite obtained by gelation or a matured wet gel composite in the presence of a surface modifier.

[0167] 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. However, in the present invention, it is preferable to use a surface modifier that includes ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) particles in the above-mentioned amount on the final manufactured aerogel composite or in the pores of the aerogel, or that includes ammonium bicarbonate (NH4HCO3) and / or ammonium carbonate ((NH4)2CO3) so that ammonia gas is generated per unit weight of the aerogel composite in the above-mentioned range when the aerogel composite is heated at a temperature of 150°C for 60 minutes.

[0168] In general, hexamethyldisilazane (HMDS) is commonly used as a surface modifier for surface modification of aerogels. However, ammonium ions (NH4) are used in the hydrophobicization process of the silica aerogel surface using hexamethyldisilazane (HMDS). + ) is formed, which reacts with carbon dioxide in the supercritical drying step to form an ammonium carbonate salt. In this case, not only is the amount of ammonium carbonate produced uncontrollable, but the ammonium carbonate produced at this time blocks the piping of the supercritical drying equipment, making it difficult to manufacture an aerogel composite. In order to solve this problem, a method of lowering the pressure of the extract during supercritical drying to lower the temperature of the extract and precipitating and removing the ammonium carbonate has been proposed. However, in this case, the residual amount of ammonium carbonate in the aerogel composite is extremely small, and thus the flame retardancy or thermal stability desired in the present invention cannot be secured.

[0169] Therefore, as the surface modifier, ammonium ion (NH4 +) can be used in an amount of 0.1 to 2 wt%, 0.5 to 1.5 wt%, or 0.5 to 1 wt%. The ammonium ion (NH4 + ) may be used in an amount of 0.1 to 2 wt%, 0.5 to 1.5 wt%, or 0.5 to 1 wt%, but is not limited thereto.

[0170] The above ammonium ion (NH4 + ) in the above content range can be prepared by heating and refluxing hexamethyldisilazane (HMDS) in the presence of an organic solvent and an acid catalyst. The reflux conditions are not particularly limited and ammonium ion (NH4 + ) can be included without limitation as long as the content is performed so as to be included in the above range, but for example, reflux can be performed at 100 to 140°C, 100 to 130°C or 100 to 120°C for 10 minutes to 6 hours, 20 minutes to 6 hours, 30 minutes to 6 hours, 30 minutes to 5 hours or 30 minutes to 4 hours.

[0171] 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, 1 to 10% by volume, or 1 to 5% by volume based on the total volume of the diluted solution.

[0172] In addition, the surface modifier may be added in an amount of 0.01 to 95 vol%, 0.1 to 90 vol%, 1 to 90 vol%, 10 to 90 vol%, 50 to 90 vol%, or 70 to 90 vol% to the wet gel composite to achieve a sufficient surface modification effect, but is not limited thereto.

[0173] In the above surface modification step, ammonium ion (NH4 +), ammonia water may be additionally added so that ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) particles are included in the above content on the final manufactured aerogel composite or within the pores of the aerogel, or when the aerogel composite is heated at a temperature of 150° C. for 60 minutes, ammonia gas may be generated in the above range per unit weight of the aerogel composite.

[0174] 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.

[0175] Drying stage

[0176] The present invention may include a drying step of drying the surface-modified wet gel composite to obtain an aerogel composite.

[0177] 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 or atmospheric pressure drying.

[0178] 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.

[0179] The process of lowering the pressure of the extract discharged from the supercritical extractor used in supercritical drying to a range of 45 to 50 bar and lowering the temperature of the extract to a temperature of 30°C or lower to induce precipitation of ammonium carbonate or ammonium hydrocarbon may not be included.

[0180] 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.

[0181] The aerogel composite provided by the present invention can be usefully used as an insulating material, heat-insulating material, or fire-retardant material for various industrial facilities, such as pipes or industrial furnaces, as well as for heat-insulating plant facilities, such as aircraft, ships, automobiles, electronic devices, and batteries.

[0182] According to another embodiment of the present invention, there is provided an insulating member comprising an aerogel composite provided by the present invention.

[0183] The above insulating member may include the above-described aerogel composite and a support member positioned on at least one of the upper and lower surfaces of the aerogel composite.

[0184] The above support member may be a structure that surrounds the front surface of the aerogel composite.

[0185] 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.

[0186] The above film-shaped support member is formed into a thin film from a polymer raw material, and examples thereof include organic films such as PET and polyimide, glass films, etc. (including metal deposition films).

[0187] 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.

[0188] 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.

[0189] 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).

[0190] 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.

[0191] The above insulating material can also be applied as an insulating material, heat-insulating material, or fire-retardant material in the fields of construction, aviation, automobiles, batteries, home appliances, semiconductors, and industrial equipment.

[0192]

[0193] 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.

[0194]

[0195] Example

[0196]

[0197] [Example 1]

[0198] 1.30 mol of ethanol and 0.02 g of acid catalyst HCl were added and mixed, and 0.62 mol of HMDS was added and mixed. After refluxing at 100°C for 1 hour, it was confirmed that ammonia (NH3) gas was generated. Through the above process, ammonium ions (NH4 +) was prepared as TMES containing 0.85 wt% of TEOS. The obtained TMES and TEOS were mixed in a molar ratio of 1:9 to prepare a silica precursor composition. The silica precursor composition and water were mixed in a molar ratio of 1:4, and ethanol having a weight ratio of 1:1 was added to the silica precursor composition to prepare a hydrated precursor solution. Hydrochloric acid was added so that the pH of the silica sol was 3 or lower to promote hydrolysis. A silica sol was prepared by adding the hydrated precursor solution and ethanol having a weight ratio of 1:3. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling the impregnation tank with 33.3 L of catalyzed silica sol, a fiber (glass fiber mat, 2 mm) was passed through it as a substrate to infiltrate the silica sol into the fiber mat at a volume ratio of 1:1 (silica sol:fiber). The fiber, which had passed through the impregnation tank and had been infiltrated with the silica sol, was passed along a conveyor belt at a constant speed and gelled for 10 minutes. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. The TMES / ethanol solution (volume ratio of 5:95) obtained above was added as a surface modifier to the wet gel composite in an amount of 90% by volume based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75°C for 4 hours. After completion of the surface modification, the wet gel composite was placed in a 70 L supercritical extractor, and CO2 was injected at 28°C and 70 bar, continuously at a rate of 70 L / min for 10 minutes. Afterwards, 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.

[0199]

[0200] [Example 2]

[0201] 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 1:3 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling 33.3 L of the catalyzed silica sol into an impregnation tank, a fiber (glass fiber mat, 3 mm) was passed through the impregnation tank to infiltrate the fiber with the silica sol, such that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fibers, which had passed through the impregnation tank and were impregnated with silica sol, were passed at a constant speed on a conveyor belt and gelled for 10 minutes. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. For surface modification, 1.30 mol of ethanol and 0.02 g of acid catalyst HCl were added and mixed, and 0.62 mol of HMDS was added and mixed. Afterwards, the mixture was refluxed at 110°C for 6 hours to remove ammonium ions (NH4 + ) was prepared by containing 0.41 wt% of TMES. As a surface modifier, the obtained TMES / ethanol solution (volume ratio 5:95) was added to the wet gel composite at 90 vol% based on the volume of the wet gel composite, and then 600 ppm of NH4 based on the weight of TMES was added. + Ammonia water was added to add ions. Surface modification was then performed at a temperature of 75 ℃ 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 for 20 minutes. After that, CO2 was vented over 2 hours, and a silica aerogel composite was manufactured.

[0202]

[0203] [Example 3]

[0204] 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 1:3 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling 33.3 L of the catalyzed silica sol into an impregnation tank, a fiber (glass fiber mat, 10 mm) was passed through the substrate to infiltrate the fiber with the silica sol, such that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fibers, which had passed through the impregnation tank and were impregnated with silica sol, were passed at a constant speed on a conveyor belt and gelled for 10 minutes. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. For surface modification, 1.30 mol of ethanol and 0.02 g of acid catalyst HCl were added and mixed, and 0.62 mol of HMDS was added and mixed. Afterwards, the mixture was refluxed at 120°C for 30 minutes to remove ammonium ions (NH4 +) was prepared as TMES containing 0.97 wt%. The TMES / ethanol solution (volume ratio 5:95) obtained above was added as a surface modifier to the wet gel composite at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ 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. Supercritical drying was performed by continuously injecting CO2 at a rate of 5 L / min for 20 minutes after a 20-minute rest period. CO2 was then vented for 2 hours, and a silica aerogel composite was manufactured.

[0205]

[0206] [Example 4]

[0207] 1.30 mol of ethanol and 0.02 g of acid catalyst HCl were added and mixed, and 0.62 mol of HMDS was added and mixed. After that, it was refluxed at 100 ℃ for 4 hours to produce ammonium ion (NH4 +) was prepared as TMES containing 0.51 wt% of TEOS. The obtained TMES and TEOS were mixed in a molar ratio of 1:9 to prepare a silica precursor composition. The silica precursor composition and water were mixed in a molar ratio of 1:4, and ethanol having a weight ratio of 1:1 was added to the silica precursor composition to prepare a hydrated precursor solution. Hydrochloric acid was added so that the pH of the silica sol was 3 or less to promote hydrolysis. A silica sol was prepared by adding the hydrated precursor solution and ethanol having a weight ratio of 1:3. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling the impregnation tank with 33.3 L of catalyzed silica sol, a fiber (glass fiber mat, 3 mm) was passed through it as a substrate to infiltrate the silica sol into the fiber mat at a volume ratio of 1:1 (silica sol:fiber). The fiber, which had passed through the impregnation tank and had been infiltrated with the silica sol, was allowed to pass along a conveyor belt at a constant speed and gel for 20 minutes. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. After adding 90% by volume of the TMES / ethanol solution (volume ratio 5:95) obtained above as a surface modifier to the wet gel composite, the surface was modified at a temperature of 75°C for 4 hours. After completion of the surface modification, the wet gel composite was placed in a 70 L supercritical extractor, and CO2 was injected at 28°C and 70 bar, continuously at a rate of 70 L / min for 10 minutes. Afterwards, 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.

[0208]

[0209] [Example 5]

[0210] 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 1:3 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling 33.3 L of the catalyzed silica sol into an impregnation tank, a fiber (glass fiber mat, 10 mm) was passed through the substrate to infiltrate the fiber with the silica sol, such that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fibers, which had passed through the impregnation tank and were impregnated with silica sol, were passed at a constant speed on a conveyor belt and gelled for 10 minutes. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. For surface modification, 1.30 mol of ethanol and 0.02 g of acid catalyst HCl were added and mixed, and 0.62 mol of HMDS was added and mixed. Afterwards, the mixture was refluxed at 100°C for 3 hours to remove ammonium ions (NH4 +) was prepared as TMES containing 0.62 wt%. The TMES / ethanol solution (volume ratio 5:95) obtained above was added as a surface modifier to the wet gel composite at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ 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. Supercritical drying was performed by continuously injecting CO2 at a rate of 5 L / min for 20 minutes after a 20-minute rest period. CO2 was then vented for 2 hours, and a silica aerogel composite was manufactured.

[0211]

[0212] [Comparative Example 1]

[0213] Ammonium ion (NH4 +) was mixed with TMES and TEOS at a molar ratio of 1:9 to prepare a silica precursor composition. The silica precursor composition and water were mixed at a molar ratio of 1:4, and ethanol at a weight ratio of 1:1 was added to the silica precursor composition to prepare a hydrated precursor solution. Hydrochloric acid was added so that the pH of the silica sol was 3 or lower to promote hydrolysis. A silica sol was prepared by adding the hydrated precursor solution and ethanol at a weight ratio of 1:3. A catalyzed sol was prepared by adding the silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) at a volume ratio of 99:1. After 33.3 L of the catalyzed silica sol was filled in an impregnation tank, a fiber (Glass fiber fiber mat, 3 mm) was passed through the fiber as a substrate to infiltrate the silica sol into the fiber, such that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fibers, which had passed through the impregnation tank and were impregnated with silica sol, were passed at a constant speed on a conveyor belt and gelled for 20 minutes. During this time, the ambient temperature on the conveyor belt was maintained at 25℃. Ammonium ion (NH4) was also added as a surface modifier to the wet gel composite. +) was added at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 4 hours. After completion of the 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. Thereafter, CO2 was vented over 2 hours, and a silica aerogel composite was manufactured.

[0214]

[0215] [Comparative Example 2]

[0216] Ammonium ion (NH4 +) was mixed with TMES and TEOS at a molar ratio of 1:9 to prepare a silica precursor composition. The silica precursor composition and water were mixed at a molar ratio of 1:3, and ethanol at a weight ratio of 1:1 was added to the silica precursor composition to prepare a hydrated precursor solution. Hydrochloric acid was added so that the pH of the silica sol was 3 or lower to promote hydrolysis. The hydrated precursor solution and ethanol at a weight ratio of 1:2.5 were added to prepare a silica sol. A catalyzed silica sol was prepared by adding a base catalyst solution (20 wt% ammonium carbonate aqueous solution) at a volume ratio of 90:10 to the silica sol. After 33.3 L of the catalyzed silica sol was filled in an impregnation tank, a fiber (Glass fiber fiber mat, 10 mm) was passed through the fiber as a substrate to infiltrate the silica sol into the fiber, such that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fibers, which had passed through the impregnation tank and were impregnated with silica sol, were gelled for 20 minutes while passing at a constant speed on a conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 25℃. HMDS / ethanol solution (volume ratio 1:19) was added as a surface modifier to the wet gel composite in an amount of 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 70℃ for 2 hours. After completion of the surface modification, the prepared silica gel-fiber composite was placed in a 70 L supercritical extractor, and CO2 was continuously injected at 80℃ and 160 bar at a rate of 6.5 L / min. After extraction for 20 minutes, CO2 was continuously injected at 80℃ and 160 bar at a rate of 6.5 L / min for another 20 minutes, and the discharged extract was transferred to a pressure control valve connected to the supercritical extractor, and the pressure was reduced to 50 bar through the pressure control valve. The above continuous injection, extraction, continuous injection and discharge processes were repeated several times (4 times).The temperature of the extract was lowered to 25°C to 30°C to precipitate ammonium carbonate and ammonium bicarbonate, which were then removed through a 100-mesh filter connected to a pressure regulating valve.

[0217]

[0218] [Comparative Example 3]

[0219] 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 1:3 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling 33.3 L of the catalyzed silica sol into an impregnation tank, a fiber (glass fiber mat, 2 mm) was passed through the impregnation tank to infiltrate the fiber with the silica sol, such that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fibers, which had passed through the impregnation tank and were impregnated with silica sol, were passed at a constant speed on a conveyor belt and gelled for 10 minutes. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. For surface modification, 1.30 mol of ethanol and 0.02 g of acid catalyst HCl were added and mixed, and 0.62 mol of HMDS was added and mixed. Afterwards, the mixture was refluxed at 90°C for 30 minutes to remove ammonium ions (NH4 +) was prepared containing 4.57 wt% of TMES. The TMES / ethanol solution (volume ratio 5:95) obtained above was added as a surface modifier to the wet gel composite at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ 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. Supercritical drying was performed by continuously injecting CO2 at a rate of 5 L / min for 20 minutes after a 20-minute rest period. CO2 was then vented for 2 hours, and a silica aerogel composite was manufactured.

[0220]

[0221] [Experimental Example 1]

[0222] In order to evaluate the content of ammonium carbonate or ammonium bicarbonate included in the aerogel composite manufactured according to the present invention, the amount of ammonia generated was measured after heating the aerogel composite specimen at 150°C, taking advantage of the fact that ammonium carbonate and ammonium bicarbonate are thermally decomposed into carbon dioxide and water vapor when heated. Specifically, five square specimens measuring 1 cm X 1 cm were obtained from each of the aerogel composites of the examples and comparative examples. More specifically, four specimens were obtained by positioning a location 10 cm apart from each corner of the aerogel composite manufactured in a rectangular shape, measuring 12 cm X 60 cm, in the center of the specimen, and one specimen was obtained by positioning the center of the aerogel composite, also in the center of the specimen. For quantitative analysis, 5 μL of an ammonia solution with a concentration of 0.28% was taken and placed in a 20 mL headspace vial, sealed, and heated at 150 ℃ for 1 hour, and then headspace-GC / NCD analysis was performed. A one-point calibration curve was obtained using the peak area obtained at this time. Next, the specimen was placed in a 20 mL headspace vial, sealed, and headspace-GC / NCD analysis was performed using the same method. The peak area obtained at this time was substituted into the calibration curve to obtain the ammonia content generated in the specimen. The average value of the ammonia generation amount (㎍ / g) per unit weight of the specimen measured in five specimens is shown in Table 1 below. Based on the measured ammonia generation amount, the content (ppm) of ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) present in the aerogel composite was converted and shown together in Table 1 below.

[0223] Weight of the sample (g)NH3 generation amount (㎍ / g)(NH4)2CO3 content (ppm)NH4HCO3 content (ppm)Example 10.03~0.0431175144Example 20.06~0.071810284Example 30.31~0.3538214176Example 40.09~0.11126856Example 50.15~0.19169076Comparative example 10.10~0.1152823Comparative example 20.18~0.3042319Comparative example 30.04~0.0691513422

[0224] As shown in Table 1 above, the aerogel composites (Examples 1 to 5) according to the present invention generated ammonia gas in an amount of approximately 10 to 50 μg / g when heated at 150°C for 1 hour. However, the aerogel composites of Comparative Examples 1 and 2 released very small amounts of ammonia gas, 5 μg / g and 4 μg / g, respectively, when heated, and the aerogel composite of Comparative Example 3 released a very large amount, 91 μg / g. From this, it was found that the aerogel composite according to the present invention contained a larger amount of ammonium carbonate or ammonium bicarbonate than Comparative Examples 1 and 2, and a smaller amount than Comparative Example 3.

[0225]

[0226] [Experimental Example 2]

[0227] In order to evaluate the thermal stability of the aerogel composite manufactured according to the present invention at a high temperature of 300 ℃, the aerogel composites manufactured in the examples and comparative examples were maintained at an isothermal temperature of 300 ℃ for 1 hour, and the weight retention rate of the aerogel composites over time was analyzed. However, for this analysis, five square specimens measuring 1 cm X 1 cm were obtained from the aerogel composites manufactured from each example and comparative example in the same manner as Experimental Example 1. At this time, in order to exclude the influence of moisture according to the storage environment of each analysis sample, each specimen was pre-heat treated at 150 ℃ for 1 hour. Thereafter, the specimens were additionally cut into a size suitable for the Mettler Toledo TGA2 analysis equipment, and each specimen was placed in the crucible of the Mettler Toledo TGA2 equipment, and the temperature was increased to 300 ℃ at a heating rate of 100 ℃ / min, and the weight loss rate was measured compared to the initial (after 150 ℃, 1 hour heat treatment) at 300 ℃ for 1 hour. The values ​​obtained by averaging the results of weight retention and weight loss rates for each time for five specimens are shown in Table 2 below.

[0228] 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 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 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 3 below. However, in Table 3 below, the average value (b) of the weight retention rate and the deviation percentage (A) were rounded off from the fifth decimal place of the calculated value and shown to the fourth decimal place.

[0229] [Formula 2]

[0230] A = {(Weight retention rate measured after heating for x hours (a)) - (Average of weight retention rates after heating (b))} / (Average of weight retention rates after heating (b)) X 100

[0231] Example 1 Hour (% by weight) Weight retention rate Weight loss rate 5 minutes (300 sec) 99.47 24 0.52 7 6 10 minutes (600 sec) 99.39 7 0.60 3 15 minutes (900 sec) 99.37 8 20.62 18 20 minutes (1200 sec) 99.35 9 30.64 0 7 25 minutes (1500 sec) 99.34 0 5 0.65 9 5 30 minutes (1800 sec) 99.34 0 5 0.65 9 5 40 minutes (2400 sec) 99.30 28 0.69 7 250 minutes (3000 sec) 99.30 28 0.69 7 260 minutes (3600 sec) 99.30 28 0.69 7 2 Example 2 Hour Weight retention rate Weight loss rate 5 minutes (300 sec) sec)98.33561.664410 minutes (600 seconds)98.20241.797615 minutes (900 seconds)98.15251.847520 minutes (1200 seconds)98.11921.880825 minutes (1500 seconds)98.10251.897530 minutes (1800 seconds)98.08591.914140 minutes (2400 seconds)98.05261.947450 minutes (3000 seconds)98.03591.964160 minutes (3600 seconds)98.01931.9807Example 3 hoursWeight retention rateWeight loss rate5 minutes (300 sec)97.55042.449610 minutes (600 seconds)97.36892.631115 minutes (900 seconds)97.31452.685520 minutes (1200 seconds)97.262.7425 minutes (1500 seconds)97.22372.776330 minutes (1800 seconds)97.20562.794440 minutes (2400 seconds)97.15122.848850 minutes (3000 seconds)97.1332.86760 minutes (3600 seconds)97.09672.9033Example 4 hoursWeight retention rateWeight loss rate5 minutes (300 sec)99.35870.641310 minutes (600 seconds)99.21860.781415 minutes (900 seconds)99.14490.855120 minutes (1200 seconds)99.0860.91425 minutes (1500 seconds)99.04170.958330 minutes (1800 seconds)98.99751.002540 minutes (2400 seconds)98.92381.076250 minutes (3000 seconds)98.87221.127860 minutes (3600 seconds)98.81321.1868Example 5 hoursWeight retention rateWeight loss rate5 minutes (300 98.17541.824610 minutes (600 seconds) 98.08641.913615 minutes (900 seconds) 97.99982.000220 minutes (1200 seconds) 97.99212.007925 minutes (1500 seconds) 97.98152.018530 minutes (1800 seconds) 97.96872.031340 minutes (2400 seconds) 97.94712.052950 minutes (3000 seconds) 97.92332.076760 minutes (3600 seconds) 97.90252.0975 Comparison Example 1 hour Weight maintenance rate Weight loss rate 5 minutes (300 sec)99.17110.828910 minutes (600 seconds)98.7281.27215 minutes (900 seconds)98.30571.694320 minutes (1200 seconds)97.93212.067925 minutes (1500 seconds)97.6052.39530 minutes (1800 seconds)97.32132.678740 minutes (2400 seconds)96.88863.111450 minutes (3000 seconds)96.47933.520760 minutes (3600 seconds)96.12763.8724Comparison Example 2 HoursWeight Maintenance RateWeight Loss Rate5 minutes (300 sec)99.17270.827310 minutes (600 seconds)98.4821.51815 minutes (900 seconds)97.99212.007920 minutes (1200 seconds)97.59052.409525 minutes (1500 seconds)97.24522.754830 minutes (1800 seconds)96.92393.076140 minutes (2400 seconds)96.37783.622250 minutes (3000 seconds)95.90394.096160 minutes (3600 seconds)95.47834.5217Comparison Example 3 hoursWeight retention rateWeight loss rate5 minutes (300 99.78640.213610 minutes (600 seconds) 98.60241.397615 minutes (900 seconds) 97.35462.645420 minutes (1200 seconds) 97.15492.845125 minutes (1500 seconds) 96.91543.084630 minutes (1800 seconds) 96.71643.283640 minutes (2400 seconds) 96.3153.68550 minutes (3000 seconds) 96.01983.980260 minutes (3600 seconds) 95.87614.1239.

[0232] Example 1 Hour (% by weight) Weight retention (a) Average value (b) Deviation percentage (A) 5 minutes (300 seconds) 99.472 499.38 130.09 17 10 minutes (600 seconds) 99.39 70.015 8 15 minutes (900 seconds) 99.37 82- 0.003 120 minutes (1200 seconds) 99.35 93- 0.022 125 minutes (1500 seconds) 99.34 05- 0.04 11 30 minutes (1800 seconds) 99.34 05- 0.04 11 Example 2 Hour Weight retention (a) Average value (b) Deviation percentage (A) 5 minutes (300 seconds) 99.47 2499.38 130 minutes (1800 seconds) 99.39 70.015 8 15 minutes (900 seconds) 99.37 82- 0.003 120 minutes (1200 seconds) 99.35 93- 0.022 125 minutes (1500 seconds) 99.34 05- 0.04 11 sec)98.335698.16640.172410 min (600 sec)98.20240.036715 min (900 sec)98.1525- 0.014120 min (1200 sec)98.1192- 0.048025 min (1500 sec)98.1025- 0.065030 min (1800 sec)98.0859- 0.0820Example 3 Hour Weight Retention Rate (a) Average Value (b) Deviation Percentage (A)5 min (300 sec)97.550497.32050.236210 min (600 sec)97.36890.049715 min (900 sec)97.3145- 0.006220 min (1200 sec) 97.26- 0.062225 min (1500 sec) 97.2237- 0.099530 min (1800 sec) 97.2056- 0.1181 Example 4 Weight retention rate (a) Average value (b) Percentage deviation (A) 5 min (300 sec) 99.358799.14120.2194 10 min (600 sec) 99.21860.078 115 min (900 sec) 99.14490.0037 20 min (1200 sec) 99.086- 0.055725 min (1500 sec) 99.0417- 0.100430 min (1800 sec) 98.9975- 0.1449 Example 5 Hour Weight Retention Rate (a) Average Value (b) Deviation Percentage (A) 5 minutes (300 seconds) 98.175 498.03400.1443 10 minutes (600 seconds) 98.08640.0535 15 minutes (900 seconds) 97.9998- 0.0349 20 minutes (1200 seconds) 97.9921- 0.0427 25 minutes (1500 seconds) 97.9815- 0.0535 30 minutes (1800 seconds) 97.9687- 0.0666 Comparative Example 1 Hour Weight Retention Rate (a) Average Value (b) Deviation Percentage (A) 5 minutes (300 seconds) 99.171198.17721.012410 minutes (600 seconds) 98.7280.561015 minutes (900 seconds) 98.30570.130920 minutes (1200 seconds) 97.9321- 0.249725 minutes (1500 seconds) 97.605- 0.582830 minutes (1800 seconds) 97.3213- 0.8718 Comparative Example 2 Hour Weight Retention Rate (a) Average Value (b) Deviation Percentage (A) 5 minutes (300 seconds) 99.172797.90111.298910 minutes (600 seconds) 98.4820.593415 minutes (900 seconds) 97.99210.093020 minutes (1200 seconds) 97.5905- 0.317225 minutes (1500 seconds) 97.2452- 0.669930 min (1800 sec) 96.9239- 0.9981Comparative Example 3 Hour Weight Retention Rate (a) Average Value (b) Deviation Percentage (A) 5 min (300 sec) 99.786497.75502.0780 10 min (600 sec) 98.60240.8668 15 min (900 sec) 97.3546- 0.4096 20 min (1200 sec) 97.1549- 0.6139 25 min (1500 sec) 96.9154- 0.8589 30 min (1800 sec) 96.7164- 1.0625.

[0233] As shown in Tables 2 and 3 above, the aerogel composites according to the present invention (Examples 1 to 5) showed a small weight loss rate of the specimens after 5 minutes at a high temperature of 300°C, and almost no weight change over time. In addition, even after a long time of 60 minutes at 300°C, the weight retention rate was 97 wt% or more, and the weight loss rate was only less than 3 wt%. However, the aerogel composites of Comparative Examples 1 to 3 showed a pattern in which the weight of the aerogel composite continued to decrease during the 60 minutes of analysis, and it could be confirmed that the weight loss rate was also significantly greater than that of the examples.

[0234]

[0235] [Experimental Example 3]

[0236] In order to evaluate the moisture impregnation rate of the aerogel composite manufactured according to the present invention, a 10 cm X 10 cm sized specimen was prepared using the aerogel composite manufactured in the examples and comparative examples, and the specimen was floated on distilled water at 21±2 ℃, and a 6.4 mm mesh screen was placed on the specimen and 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 specimen before and after impregnation was measured, respectively, and the moisture impregnation rate was measured according to the following Equation 4. The results are shown in Table 4 below.

[0237] [Formula 4]

[0238] Moisture Impregnation Rate (wt%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0239] Moisture Impregnation Rate (Wt%) Example 10.8 Example 21.2 Example 3 1.5 Example 4 1.3 Example 5 1.1 Comparative Example 11.2 Comparative Example 21.5 Comparative Example 39.1

[0240] As shown in Table 4 above, the aerogel composites according to the present invention (Examples 1 to 5) have a very low moisture impregnation rate of 2 wt% or less and high water repellency. On the other hand, the aerogel composite of Comparative Example 3 has a very high moisture impregnation rate of 9.1 wt% and very low water repellency.

[0241]

[0242] [Experimental Example 4]

[0243] In order to evaluate the flame retardancy of the aerogel composite manufactured according to the present invention, the aerogel composites of Examples 3 and 5 and Comparative Example 2 were manufactured in a size of 155 mm X 800 mm X 10 mm (length X width X thickness), and the average sustained heat of combustion (Qsb) and the critical heat flux (CHF) during extinguishing were measured according to the standards of ISO 5658-2, and the results are shown in Table 5 below. At this time, the average sustained heat of combustion (Qsb) is a value obtained by multiplying the heat amount fixed for each 50 mm section by the time it takes for the flame to propagate. A large average sustained heat of combustion means a slow flame propagation speed on the surface of the specimen, and the critical heat flux (CHF) during extinguishing is a factor related to the flame propagation distance on the surface of the specimen. A large critical heat flux during extinguishing means a short flame propagation distance on the surface of the specimen.

[0244] Average continuous combustion heat (MJ / m) 2 ) Critical heat flux during digestion (kW / m) 2 )Example 31.0637.3Example 50.9236.6Comparative Example 20.3220.2

[0245] As shown in Table 5 above, the aerogel composites (Examples 3 and 5) according to the present invention have higher average sustained heat of combustion (Qsb) and critical heat flux (CHF) at extinguishment than the aerogel composite of Comparative Example 2, showing excellent flame retardancy. Although not shown in Table 5 above, the aerogel composites of Examples 1, 2, and 4 according to the present invention also have an average sustained heat of combustion (Qsb) of 0.8 MJ / m 2 And the critical heat flux (CHF) during digestion is 30 kW / m 2 It was confirmed that the flame retardancy was very high.

[0246]

[0247] [Experimental Example 5]

[0248] In order to evaluate the high-temperature thermal conductivity of the aerogel composite manufactured according to the present invention, the GHP (Guarded Hot Plate) high-temperature thermal conductivity of the aerogel composite manufactured in the examples and comparative examples was measured at a temperature of approximately 150°C using a GHP 456 device from NETZSCH, and the results are shown in Table 6 below.

[0249] Thermal Conductivity (mW / mK) Example 1 18.5 Example 2 19.7 Example 3 20.0 Example 4 18.0 Example 5 19.1 Comparative Example 1 25.7 Comparative Example 2 25.9 Comparative Example 3 30.1

[0250] As shown in Table 6 above, the aerogel composites according to the present invention (Examples 1 to 5) showed lower high-temperature thermal conductivity than the aerogel composites of Comparative Examples 1 to 3, and in particular, the difference in thermal conductivity was confirmed to be large compared to Comparative Example 3. From this, it was found that the aerogel composite according to the present invention had excellent high-temperature insulation properties.

[0251] From these results, it was confirmed that the aerogel composite of the present invention has high hydrophobicity, contains ammonium carbonate or ammonium bicarbonate so that ammonia gas is generated in the above-mentioned amount in a high-temperature environment, and thus has excellent flame retardancy and thermal stability, and maintains excellent insulation performance even in a high-temperature environment.

[0252]

[0253] 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.

[0254] The present invention relates to an aerogel composite having excellent thermal stability, in which the aerogel component does not significantly decompose or lose its properties even when exposed to high temperatures for long periods of time, and the weight change over time at high temperatures is small. The aerogel composite of the present invention can be applied as an insulating material in batteries, electronic devices, automobiles, industrial equipment, structures, and the like.

Claims

1. An aerogel composite comprising a fiber substrate and an aerogel including one or more pores, The weight retention measured after heating the above aerogel composite at a temperature of 300 ℃ for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and 30 minutes satisfies the following equation 2, An aerogel composite having a weight retention of 97 wt% or more measured after heating the aerogel composite at a temperature of 300°C for 60 minutes: [Formula 2] A(%) = {(Weight retention rate measured after heating for x hours (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 time is 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, The weight retention (a) measured after heating for the above x hours is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300°C for x hours, compared to the weight of the aerogel composite before heating. 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 300 ℃ for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes. The above A is - 0.50 to + 0.

50.

2. In paragraph 1, The above A is an aerogel composite of - 0.30 to + 0.

30.

3. 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 300 ℃ for 5 minutes and 60 minutes satisfies the following equation 3: [Formula 3] B = |{(Weight retention measured after heating for y hours) - (Weight retention measured after heating for z hours)} / (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 hours is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300°C for y hours, compared to the weight of the aerogel composite before heating. The weight retention measured after heating for the above z hours is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300°C for z hours, relative to the weight of the aerogel composite before heating. The above B is 1.0 X 10 -3 4.0 X 10 -2 am.

4. 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 300°C for 5 minutes and 30 minutes satisfies the following equation 3: [Formula 3] B = |{(Weight retention measured after heating for y hours) - (Weight retention measured after heating for z hours)} / (y - z)| In the above equation 3, y is 5 minutes, z is 30 minutes, The weight retention measured after heating for the above y hours is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300°C for y hours, relative to the weight of the aerogel composite, The weight retention measured after heating for the above z hours is the percentage (%) of the weight of the aerogel composite measured after heating the aerogel composite at a temperature of 300°C for z hours, relative to the weight of the aerogel composite, The above B is 1.0 X 10 -3 3.0 X 10 -2 am.

5. In paragraph 1, An aerogel composite having a moisture content of 5 wt% or less, as expressed 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 impregnation in distilled water at 21±2°C for 15 minutes.

6. In paragraph 5, An aerogel composite having a moisture impregnation rate expressed by the above formula 4 of 2 wt% or less.

7. In paragraph 1, An aerogel composite having a weight retention of 97 wt% or more measured after heating the aerogel composite at a temperature of 300°C for 30 minutes.

8. In paragraph 1, The average sustained heat of combustion (Qsb) measured according to ISO 5658-2 standard in the above aerogel composite is 0.5 MJ / m 2 Ideal, aerogel composite.

9. In paragraph 1, The critical heat flux (CHF) during digestion measured according to ISO 5658-2 standard in the above aerogel composite is 25 kW / m 2 Ideal, aerogel composite.

10. In paragraph 1, An aerogel composite having a thermal conductivity at room temperature (23±5 ℃) of 15.0 mW / mK or less.

11. In paragraph 1, An aerogel composite having a thermal conductivity of 25.0 mW / mK or less at 150°C.

12. In paragraph 1, An aerogel composite, wherein the amount of ammonia gas generated per unit weight of the aerogel composite when the aerogel composite is heated at a temperature of 150°C for 60 minutes is 10 to 70 μg / g.

13. In paragraph 12, An aerogel composite, wherein the amount of ammonia gas generated per unit weight of the aerogel composite when the aerogel composite is heated at a temperature of 150°C for 60 minutes is 10 to 50 μg / g.

14. In paragraph 12, The aerogel composite comprises ammonium bicarbonate (NH4HCO3) or ammonium carbonate ((NH4)2CO3) particles on the aerogel or within the pores of the aerogel, such that when heated at a temperature of 150°C for 60 minutes, ammonia gas is generated in an amount of 10 to 70 μg / g per unit weight of the aerogel composite.

15. In paragraph 1, The above aerogel is an aerogel composite, which is a silica aerogel.

16. In paragraph 1, An aerogel composite wherein the above fiber substrate is a glass fiber substrate.

17. An insulating member comprising an aerogel composite according to any one of claims 1 to 16.

18. In paragraph 17, 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.