Aerogel composite

Abstract

The present invention relates to an aerogel composite, which exhibits high hydrophobicity and has a low volatile organic compound (VOC) generation amount to suppress odor generation even when used in a high-temperature environment.

Description

Aerogel complex

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

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0004967 filed January 13, 2025 and U.S. Patent Application No. 19 / 192,745 filed April 29, 2025, and all contents disclosed in the documents of said patent applications are incorporated herein as part of this specification.

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

[0004] Aerogels are ultraporous materials with a high specific surface area (≥500 m²) having a porosity of approximately 90.0% to 99.9% and a pore size in the range of 1 nm to 100 nm. 2 As a material with a g content, it is a material possessing excellent properties such as ultralight weight, ultra-insulating insulation, and ultra-low dielectric strength. Accordingly, active research is being conducted not only on the development of aerogel materials but also on their application as transparent and eco-friendly high-temperature insulating materials, ultra-low dielectric thin films for high-density integrated devices, catalysts and catalyst supports, electrodes for supercapacitors, and electrode materials for seawater desalination.

[0005] The biggest advantage of aerogel is that it has super-insulation properties with a thermal conductivity of 0.030 W / m·K or less, which is lower than conventional organic insulation materials such as styrofoam, and it can solve the fatal weaknesses of organic insulation materials, such as fire vulnerability and the generation of harmful gases during a fire.

[0006] Aerogel blankets, in which aerogel is formed on fibers, are widely used in construction or industrial sites as functional thermal insulation materials. Additionally, they can be usefully employed as insulation, thermal insulation, or non-combustible materials for aircraft, ships, automobiles, batteries, and more.

[0007] Meanwhile, these aerogel blankets are manufactured by preparing a silica sol from silica precursors such as water glass and alkoxysilane series (TEOS, TMOS, MTMS, etc.), mixing fibers into the sol, and then gelling and drying.

[0008] However, when aerogel blankets manufactured in this way are actually used, a problem arises in which the aerogel absorbs moisture from the air, causing a decrease in thermal insulation performance. Therefore, to prevent this, a surface modification process is added during the manufacturing process of aerogel blankets after gelation and before drying to hydrophobize the surface of the silica aerogel. However, in the case of hydrophobic silica aerogel blankets, when applied to high-temperature environments such as high-temperature piping, volatile organic compounds (VOCs) are generated, causing a serious odor problem.

[0009] One objective of the present invention is to provide an aerogel composite or an insulating member containing the same, wherein the amount of VOC (volatile organic compound) generated is reduced and odor generation is suppressed even when the aerogel composite is used in a high-temperature environment, while the hydrophobicity of the aerogel composite is still maintained at a high level.

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

[0011] According to one embodiment of the present invention, the invention relates to an aerogel composite comprising a substrate and an aerogel having a plurality of open pores, wherein the aerogel composite comprises carbon (C), silicon (Si), and oxygen (O), and the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite is 2 or more and 3 or less. The total carbon content of the aerogel composite may refer to the content of carbon (weight%) included therein when the total sum of the carbon, silicon, and oxygen contents is set to 100 weight% based on the total thickness of the aerogel composite.

[0012] The carbon content on the surface of the aerogel composite may refer to the carbon content (weight%) contained therein when the total sum of carbon, silicon, and oxygen content in the region from the surface of the aerogel composite to a depth of approximately 10 nm is set to 100 weight%.

[0013] The ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.9 or less.

[0014] The ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.85 or less.

[0015] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, silicon may be included in an amount of 20 to 50 weight%.

[0016] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, silicon may be included in an amount of 30 to 50 weight%.

[0017] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, silicon may be included in an amount of 35 to 45 weight%.

[0018] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, oxygen may be included in an amount of 30 to 60 weight%.

[0019] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, oxygen may be included in an amount of 40 to 60 weight%.

[0020] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, oxygen may be included in an amount of 40 to 50 weight%.

[0021] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, carbon may be included in an amount of 5 to 30 weight%.

[0022] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, carbon may be included in an amount of 10 to 20 weight%.

[0023] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, carbon may be included in an amount of 10 to 15 weight%.

[0024] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, carbon may be included in an amount of 10 to 14.63 weight%.

[0025] When the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite, silicon may be included in an amount of 20 to 50 weight%.

[0026] When the total content of carbon, silicon, and oxygen is 100 weight% based on the total thickness of the aerogel composite, silicon may be included in an amount of 25 to 45 weight%.

[0027] When the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite, oxygen may be included in an amount of 40 to 75 weight%.

[0028] When the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite, oxygen may be included in an amount of 50 to 70 weight%.

[0029] When the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite, carbon may be included in an amount of 1 to 20 weight%.

[0030] When the total content of carbon, silicon, and oxygen is 100 weight% based on the total thickness of the aerogel composite, carbon may be included in an amount of 3 to 10 weight%.

[0031] The ratio of the total carbon content to the total silicon content of the above aerogel composite may be 0.05 or more and 0.30 or less.

[0032] The ratio of the total carbon content to the total silicon content of the above aerogel composite may be 0.05 or more and 0.25 or less.

[0033] The ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite may be 0.9 or more and 2.0 or less.

[0034] The ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite may be 0.95 or more and 1.70 or less.

[0035] The ratio of oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite may be 0.5 or more and 1.0 or less.

[0036] The ratio of oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite may be 0.6 or more and 0.9 or less.

[0037] When the above aerogel composite is heated at a temperature of 150°C for 15 minutes, the amount of trimethylethoxysilane (TMES), trimethylsilanol (TMS), or hexamethyldisiloxane (HMDSO) generated per unit weight of the aerogel composite may be 10 μg / g or less.

[0038] The above aerogel composite may have a moisture impregnation rate (weight%) represented by the following Formula 1 of 15 weight% or less:

[0039] [Equation 1]

[0040] Moisture impregnation rate (weight%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0041] In the above Equation 1, the weight of the specimen after impregnation refers to the weight of the aerogel composite specimen after impregnating it in distilled water at 21±2 ℃ for 15 minutes.

[0042] The moisture impregnation rate (weight%) of the above aerogel composite, represented by Formula 1, may be 11 weight% or less.

[0043] The thickness of the above aerogel composite may be 0.5 mm to 20 mm, 0.5 mm to 15 mm, or 0.5 mm to 10 mm.

[0044] The density of the above aerogel composite is 0.05 to 0.50 g / cm³ 3 , 0.10 to 0.35 g / cm² 3 or 0.15 to 0.30 g / cm² 3 It could be.

[0045] The above aerogel may comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

[0046] The above aerogel may include secondary aerogel particles formed by the aggregation or bonding of multiple primary aerogel particles having a particle size greater than 0 and less than 5 nm.

[0047] According to another embodiment of the present invention, the invention relates to an insulating member comprising the aerogel composite described above.

[0048] The above insulating member may further include a support member located on at least one of the upper and lower surfaces of the aerogel composite.

[0049] The aerogel composite provided in the present invention has a low carbon content on the surface, which reduces the generation of VOCs (volatile organic compounds) and suppresses odor generation even when the aerogel composite is used in a high-temperature environment, while maintaining a high degree of hydrophobicity inside the pores of the aerogel composite, thereby preventing the degradation of thermal insulation performance caused by the aerogel composite absorbing moisture from the air.

[0050] According to one embodiment of the present invention, the invention relates to an aerogel composite comprising a substrate and an aerogel having a plurality of open pores, wherein the aerogel composite comprises carbon (C), silicon (Si), and oxygen (O), and the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite is 2 or more and 3 or less.

[0051] The ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.9 or less.

[0052] The ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.85 or less.

[0053] The total carbon content of the above aerogel composite may refer to the carbon content (weight%) contained therein when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the above aerogel composite.

[0054] The carbon content on the surface of the aerogel composite may refer to the carbon content (weight%) contained therein when the total sum of carbon, silicon, and oxygen content in the region from the surface of the aerogel composite to a depth of approximately 10 nm is set to 100 weight%.

[0055] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, silicon may be included in an amount of 20 to 50 weight%, oxygen in an amount of 30 to 60 weight%, and carbon in an amount of 5 to 30 weight%.

[0056] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, silicon may be included in an amount of 30 to 50 weight%, oxygen in an amount of 40 to 60 weight%, and carbon in an amount of 10 to 15 weight%.

[0057] When the total content of carbon, silicon, and oxygen on the surface of the above aerogel composite is 100 weight%, silicon may be included in an amount of 35 to 45 weight%, oxygen in an amount of 40 to 50 weight%, and carbon in an amount of 10 to 20 weight%.

[0058] When the total content of carbon, silicon, and oxygen is 100 weight% based on the total thickness of the aerogel composite, silicon may be included in an amount of 20 to 50 weight%, oxygen in an amount of 40 to 75 weight%, and carbon in an amount of 1 to 20 weight%.

[0059] The ratio of the total carbon content to the total silicon content of the above aerogel composite may be 0.05 or more and 0.30 or less.

[0060] The ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite may be 0.9 or more and 2.0 or less.

[0061] The ratio of oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite may be 0.5 or more and 1.0 or less.

[0062] When the above aerogel composite is heated at a temperature of 150°C for 15 minutes, the amount of trimethylethoxysilane (TMES), trimethylsilanol (TMS), or hexamethyldisiloxane (HMDSO) generated per unit weight of the aerogel composite may be 10 μg / g or less.

[0063] The above aerogel composite may have a moisture impregnation rate (weight%) represented by the following Formula 1 of 15 weight% or less, preferably 11 weight% or less:

[0064] [Equation 1]

[0065] Moisture impregnation rate (weight%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0066] In the above Equation 1, the weight of the specimen after impregnation refers to the weight of the aerogel composite specimen after impregnating it in distilled water at 21±2 ℃ for 15 minutes.

[0067] The thickness of the above aerogel composite may be 0.1 mm to 20 mm.

[0068] The density of the above aerogel composite is 0.05 to 0.50 g / cm³ 3 It could be.

[0069] The above aerogel may comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

[0070] The above aerogel may include secondary aerogel particles formed by the aggregation or bonding of multiple primary aerogel particles having a particle size greater than 0 and less than 5 nm.

[0071] According to another embodiment of the present invention, the invention relates to an insulating member comprising the aerogel composite described above.

[0072] The above insulating member may further include a support member located on at least one of the upper and lower surfaces of the aerogel composite.

[0073] Hereinafter, the present invention will be described in more detail to aid in understanding the invention. In this case, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0074]

[0075] According to one embodiment of the present invention, the invention relates to an aerogel composite comprising a substrate; and an aerogel comprising a plurality of open pores.

[0076] The above "aerogel" comprises a plurality of primary aerogel particles having a size of approximately greater than 0 and less than 10 nm, greater than 0 and less than 5 nm, and secondary aerogel particles formed by the aggregation or bonding of these primary aerogel particles, and as a plurality of open pores are formed between the primary aerogel particles and between the secondary aerogel particles to form aggregates, the aerogel forms a three-dimensional network structure.

[0077] The above "aerogel particles" are particles in the form of individual solid units constituting the aerogel, and may include primary aerogel particles having a size of approximately greater than 0 and less than 10 nm, or greater than 0 and less than 5 nm, preferably around 1 nm, and secondary aerogel particles formed by the aggregation of these particles. However, the aerogel within the aerogel composite may mostly consist of secondary aerogel particles or a form in which they are aggregated and bonded, and a small amount of primary aerogel particles that do not form secondary aerogel particles may be mixed in. The above secondary aerogel particles may have an average particle size of approximately 5 to 2,000 nm, 5 to 1,000 nm, 5 to 500 nm, 5 to 100 nm, or 5 to 50 nm, but are 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 scanning electron microscopy, dynamic light scattering, optical microscopy, or size exclusion methods, but is not limited thereto.

[0078] The aerogel may have a matrix framework structure including mesopores, and may include micropores or macropores in addition to the mesopores. Here, the "mesopore" is a pore with an average pore diameter in the range of about 2 nm to about 50 nm, the "macropore" is a pore with an average pore diameter exceeding about 50 nm, and the "micropore" is a pore with an average pore diameter less than about 2 nm. In the present invention, the aerogel may contain at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% mesopores of the pore volume of the framework structure. In one embodiment, the aerogel of the present invention may include mesopores. In one embodiment, 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 gas adsorption experiments, mercury infiltration, capillary flow porometry, or positron annihilation lifetime spectroscopy (PALS), but is not limited thereto.

[0079] Examples of the above-described material may include discrete fibers, films, sheets, nets, fibers, porous materials, foams, nonwoven materials, or laminates of two or more layers thereof. Additionally, depending on the application, the surface may have surface roughness or be patterned. The above-described material may be a fiber material comprising a plurality of fibers.

[0080] The above description refers to polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate, regenerated cellulose (e.g., rayon), cotton, polyamide (e.g., nylon), spandex (e.g., Lycra from DuPont), carbon (e.g., graphite), polyacrylonitrile (PAN), PAN oxide, 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, e.g., quartz (e.g., Saint-Gobain Quartzel), Q-Fiber felt (from Johns Manville), Saffil, Durablanket (from Uniflex), or other silica fibers, Duraback (from carborundum), polyaramid fibers, e.g., Kevlar, Nomex, Sontera (all from DuPont), Conex (from Tyzine), polyolefins, e.g., Tyvek It may include (made by DuPont), Dyneema (made by DSM), Spectra (made by Honeywell), other polypropylene fibers such as Typar and Xavan (both made by DuPont), fluoropolymers such as PTFE under the brand name Teflon (made by DuPont), Goretex (made by WL GORE), silicon carbide fibers such as Nicalcon (made by COI Ceramics), ceramic paper, ceramic fibers such as Nextel (made by 3M), acrylic polymers, basalt fibers, wool, silk, hemp, leather, suede fibers, PBO-Xylon fibers (made by Tyobo), liquid crystal materials such as Vectan (made by Hoechst), Cambrel fibers (made by DuPont), polyurethane, wool fibers, boron, aluminum, iron, stainless steel fibers, or other thermoplastic resins such as PEEK, PES, PET, PEK, PPS, etc., but any fiber that can further improve thermal insulation performance by including a space or void where the insertion of aerogel is easy may be used without limitation.The above material may include, but is not limited to, glass fibers, basalt fibers, ceramic fibers, and / or ceramic paper. The above material may be glass fibers, but is not limited thereto.

[0081] When using a substrate containing fibers as the above material, the aerogel composite has a structure in which at least some of a plurality of aerogel particles are dispersed, preferably bonded, on the surface of the substrate containing fibers, and at the same time, at least some of a plurality of aerogel particles are dispersed, preferably located, in the empty spaces between the dispersed fibers within the substrate.

[0082] Generally, in the manufacture of aerogel composites, hydrophobicity is imparted to the composite through a surface modification process to prevent the degradation of thermal insulation performance caused by moisture penetration when the aerogel composite is applied as an insulating material. However, when hydrophobized aerogel composites are exposed to high-temperature environments during actual use, a large amount of VOCs (volatile organic compounds) is generated, causing discomfort to users or workers due to unpleasant odors. In this invention, the degree of hydrophobicity is lowered only on the surface of the surface-modified aerogel composite while maintaining a high degree of hydrophobicity within the aerogel pores, thereby reducing the amount of VOCs generated while also preventing the degradation of thermal insulation performance caused by moisture.

[0083] In addition, the aerogel may be an inorganic silica aerogel formed from a silicon alkoxide-based compound or water glass as a precursor. The aerogel may comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof. The aerogel may have at least some of the SiO2 on the surface of the SiO2 network structure having a bonding structure of Si-O-SiO2(CH3), Si-O-SiO(CH3)2, or Si-O-Si(CH3)3. The specific manufacturing process of the silica aerogel is described in detail below.

[0084] Accordingly, the aerogel composite in the present invention includes silicon (Si), oxygen (O), and carbon (C) as essential elements.

[0085] When the total content of silicon, oxygen, and carbon in the above aerogel composite is 100 weight%, silicon may be included in an amount of 20 to 50 weight%, 20 to 45 weight%, 25 to 50 weight%, or 25 to 45 weight%.

[0086] In addition, when the total content of silicon, oxygen, and carbon in the above aerogel composite is 100 wt%, oxygen may be included in an amount of 40 to 75 wt%, 40 to 70 wt%, 45 to 75 wt%, 45 to 70 wt%, 50 to 75 wt%, or 50 to 70 wt%.

[0087] In addition, when the total content of silicon, oxygen, and carbon in the above aerogel composite is 100 wt%, carbon may be included in an amount of 1 to 20 wt%, 1 to 15 wt%, 1 to 10 wt%, 2 to 20 wt%, 2 to 15 wt%, 2 to 10 wt%, 3 to 20 wt%, 3 to 15 wt%, or 3 to 10 wt%.

[0088] In addition, when the total sum of silicon, oxygen, and carbon content in the aerogel composite is 100 weight%, the ratio of carbon content to silicon content may be 0.05 or more and 0.30 or less, 0.05 or more and 0.25 or less, 0.05 or more and 0.23 or less, 0.08 or more and 0.30 or less, 0.08 or more and 0.25 or less, or 0.08 or more and 0.23 or less.

[0089] The aerogel composite is characterized by having a ratio of carbon content on the surface of the aerogel composite to the total carbon content being 2 or more and 3 or less. Specifically, the ratio of carbon content on the surface of the aerogel composite to the total carbon content may be 2 or more and 2.9 or less, or 2 or more and 2.85 or less, or 2.1 or more and 2.85 or less.

[0090] In the present invention, an aerogel composite in which the ratio of carbon content on the surface to the total carbon content satisfies the above range exhibits very low levels of generation of trimethylethoxysilane (TMES), trimethylsilanol (TMS), or hexamethyldisiloxane (HMDSO) even in high-temperature environments of 150°C or higher, and the hydrophobicity of the aerogel composite is also excellent. However, if the ratio of carbon content on the surface to the total carbon content is below the above range, the hydrophobicity of the aerogel composite is too low, and performance degradation occurs due to the influence of moisture. On the other hand, if the ratio of carbon content on the surface to the total carbon content exceeds the above range, the generation of VOCs (volatile organic compounds) such as TMES, TMS, and HMDSO increases in high-temperature environments, which may lead to odor problems.

[0091] In this specification, "total carbon content of the aerogel composite" is obtained through XRF analysis and refers to the ratio (weight%) of the carbon content when the total sum of carbon, silicon, and oxygen content is set to 100 weight% based on the total thickness of the aerogel composite.

[0092] In this specification, "ratio of carbon content on the surface of the aerogel composite" is obtained through XPS analysis and refers to the ratio (weight%) of carbon content when the total sum of carbon, silicon, and oxygen content is 100 weight% in the region from the surface of the aerogel composite to a depth of about 10 nm.

[0093] When the total content of silicon, oxygen, and carbon on the surface of the above-mentioned aerogel composite is 100 wt%, silicon may be included in an amount of 20 to 50 wt%, 20 to 45 wt%, 25 to 50 wt%, 25 to 45 wt%, 30 to 50 wt%, 30 to 45 wt%, 35 to 50 wt%, or 35 to 45 wt%.

[0094] When the total content of silicon, oxygen, and carbon on the surface of the above aerogel composite is 100 wt%, oxygen may be included in an amount of 30 to 60 wt%, 30 to 55 wt%, 30 to 50 wt%, 35 to 60 wt%, 35 to 55 wt%, 35 to 50 wt%, 40 to 60 wt%, 40 to 55 wt%, or 40 to 50 wt%.

[0095] When the total content of silicon, oxygen, and carbon on the surface of the above-mentioned aerogel composite is 100 wt%, carbon may be included in an amount of 5 to 30 wt%, 5 to 25 wt%, 5 to 20 wt%, 7 to 30 wt%, 7 to 25 wt%, 7 to 20 wt%, 10 to 30 wt%, 10 to 25 wt%, 10 to 20 wt%, 10 to 15 wt%, or 10 to 14.63 wt%.

[0096] In addition, when the total sum of silicon, oxygen, and carbon content on the surface of the aerogel composite is 100 weight%, the ratio of carbon content to silicon content may be 0.20 or more and 0.60 or less, 0.20 or more and 0.55 or less, 0.20 or more and 0.50 or less, 0.25 or more and 0.60 or less, 0.25 or more and 0.55 or less, or 0.25 or more and 0.50 or less.

[0097] The above aerogel composite is characterized by the ratio of silicon content on the surface of the aerogel composite to the total silicon content being 0.9 or more and 2.0 or less, 0.9 or more and 1.8 or less, or 0.95 or more and 1.70 or less.

[0098] In addition, the aerogel composite of the present invention is characterized in that the ratio of oxygen content on the surface of the aerogel composite to the total oxygen content is 0.5 or more and 1.0 or less, 0.5 or more and 0.9 or less, 0.6 or more and 1.0 or less, or 0.6 or more and 0.9 or less.

[0099] The content of silicon, oxygen, and carbon based on the total thickness of the above-described aerogel composite was analyzed using an XRF (X-ray fluorescence) component analyzer. XRF analysis is a device that analyzes a sample using fluorescent X-rays generated from the sample after X-rays are irradiated onto the sample. When high voltage and current are applied to an X-ray tube, X-rays are emitted. When the emitted X-rays are irradiated onto a sample, they excite electrons within the orbits of elements present in the sample. As the excited electrons return to the ground state, characteristic fluorescent X-rays are emitted according to each element. At this time, when the emitted fluorescent X-rays are diffracted by a spectroscopic crystal, analysis results can be obtained using a detector. In the present invention, the content of each component during the XRF analysis was obtained by taking five circular specimens with a diameter of approximately 30 mm from the aerogel composite and calculating the average value of the silicon, oxygen, and carbon content (weight%) measured from each specimen. At this time, five specimens can be obtained by making the center of the specimen 10 cm away from each corner of an aerogel composite manufactured in a rectangular shape (e.g., 60 cm x 12 cm in size, but not limited thereto), and by making the center of the specimen 1 part of the aerogel composite the center of the specimen.

[0100] In addition, the content of silicon, oxygen, and carbon in the region extending to a depth of approximately 10 nm from the externally exposed surface of the aerogel composite was analyzed using an XPS (X-ray Photoelectron Spectroscopy) component analyzer. At this time, the content of each component was obtained in atomic (at)%, which was converted to weight% in this specification. In the present invention, the content of each component during the XPS analysis was obtained by obtaining five rectangular specimens from the aerogel composite with dimensions of 10 mm x 10 mm and a thickness corresponding to the thickness of the aerogel composite, and then calculating the average value of the silicon, oxygen, and carbon content (weight%) measured from each specimen. The method of obtaining the five specimens can be performed in the same way as the XRF analysis method.

[0101] When the above aerogel composite is heated at a temperature of 150°C for 15 minutes, the amount of trimethylethoxysilane (TMES), trimethylsilanol (TMS), or hexamethyldisiloxane (HMDSO) generated per unit weight of the aerogel composite is very low, at a level of 10 μg / g or less, or less than 10 μg / g.

[0102] The above aerogel composite may have a moisture impregnation rate (weight%) represented by Formula 1 below of 15 weight% or less, 11 weight% or less, 10 weight% or less, 9 weight% or less, 8 weight% or less, or 7 weight% or less.

[0103] [Equation 1]

[0104] Moisture impregnation rate (weight%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0105] In the above Equation 1, the moisture impregnation rate can be calculated by floating a specimen of an aerogel composite measuring 10 mm x 10 mm on distilled water at 21 ± 2 ℃, placing a 6.4 mm mesh screen over the specimen and sinking it to 127 mm below the water surface for impregnation, removing the mesh screen after 15 minutes, and when the specimen floats to the surface, picking up the specimen with a clamp and suspending it vertically for 60 ± 5 seconds, then measuring the weight before and after impregnation to determine the weight increase rate. Here, a lower moisture impregnation rate indicates a higher degree of hydrophobicity of the aerogel composite.

[0106] In addition, when measuring the moisture impregnation rate above, the moisture impregnation rate measured by using an aerogel composite specimen cut into 10 mm x 10 mm pieces is considered to represent the water repellency in the cross-section of the aerogel composite.

[0107] The above moisture impregnation rate may also be obtained by calculating the average value of the moisture impregnation rates measured for five specimens. In this case, the method of obtaining five specimens is the same as in the XRF (X-ray fluorescence) analysis and XPS (X-ray Photoelectron Spectroscopy) analysis described above.

[0108] Meanwhile, the thickness of the substrate in the above-mentioned aerogel composite is not particularly limited and can be appropriately selected according to the application, but for example, it may be 0.5 to 20 mm, 0.5 to 15 mm, 0.5 to 10 mm, 0.5 to 9 mm, 0.5 to 8 mm, 0.5 to 7 mm, 0.5 to 6 mm, 0.5 to 5 mm, 0.5 to 4 mm, 0.5 to 3 mm, 0.5 to 2 mm, 0.5 to 1 mm, 1 to 20 mm, 1 to 15 mm, 1 to 10 mm, 1 to 9 mm, 1 to 8 mm, 1 to 7 mm, 1 to 6 mm, 1 to 5 mm, 1 to 4 mm, 1 to 3 mm, or 1 to 2 mm. However, it is not limited thereto.

[0109] In addition, the thickness of the aerogel composite is not specifically limited and can be appropriately selected according to the application, but, for example, it may be 0.5 to 20 mm, 0.5 to 15 mm, 0.5 to 10 mm, 0.5 to 9 mm, 0.5 to 8 mm, 0.5 to 7 mm, 0.5 to 6 mm, 0.5 to 5 mm, 0.5 to 4 mm, 0.5 to 3 mm, 0.5 to 2 mm, 0.5 to 1 mm, 1 to 20 mm, 1 to 15 mm, 1 to 10 mm, 1 to 9 mm, 1 to 8 mm, 1 to 7 mm, 1 to 6 mm, 1 to 5 mm, 1 to 4 mm, 1 to 3 mm, or 1 to 2 mm, but is not limited thereto.

[0110] In addition, the density of the aerogel composite is 0.05 to 0.50 g / cm³ 3 , 0.05 to 0.35 g / cm² 3 , 0.05 to 0.30 g / cm² 3 , 0.10 to 0.35 g / cm² 3 , 0.10 to 0.30 g / cm² 3, 0.15 to 0.35 g / cm² 3 1 or 0.15 to 0.30 g / cm² 3 It may be, but is not limited to this.

[0111] The above aerogel composite may have a thermal conductivity of 30.0 mW / mK or less, 25.0 mW / mK or less, or 20.0 mW / mK or less at room temperature (23±2 ℃), and within this range, the thermal insulation of the aerogel composite can be maximized.

[0112] The above aerogel composite may have a high temperature (150 ℃) thermal conductivity of 35.0 mW / mK or less, 30.0 mW / mK or less, or 25.0 mW / mK or less, and within this range, the thermal insulation of the aerogel composite can be maximized.

[0113] 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 preparing a specimen according to ASTM C165.

[0114] 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 ASTM D638 standards.

[0115] In the present invention, the aerogel composite may be formed by the following steps: a step of preparing a silica sol; a step of gelling after impregnating a fiber substrate with the silica sol; an aging step; a surface modification step; and a drying step. Each step is described below. However, the specific manufacturing processes or examples described herein are not intended to limit any particular type of aerogel or its manufacturing method. This specification may include any aerogel formed by any associated manufacturing method known to a person skilled in the art.

[0116] Silica sol preparation steps

[0117] First, a silica sol can be prepared by mixing a silica precursor composition and a catalyst composition.

[0118] The above silica precursor composition may include water and / or a polar organic solvent in the silica precursor.

[0119] 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-based compound. Specifically, tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetrasecondary butyl orthosilicate, tetra tertiary butyl orthosilicate, tetrahexyl orthosilicate, and tetracyclohexyl orthosilicate. It may be a tetraalkyl silicate such as tetradodecyl orthosilicate, tetradodecyl orthosilicate, etc. More specifically among these, in the case of the present invention, the silica precursor may be tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), or a mixture thereof.

[0120] In addition, the silica precursor may be a water glass solution. Here, the water glass solution may refer to a diluted solution obtained by adding distilled water to water glass and mixing it, and the water glass may be sodium silicate (Na2SiO3), which is an alkali silicate obtained by melting silicon dioxide (SiO2) and an alkali.

[0121] In addition, the silica precursor may include pre-hydrolyzed TEOS (HTEOS). HTEOS is an ethyl silicate oligomer material with a broad molecular weight distribution, and since it can control physical properties such as gelation time when synthesized from TEOS monomers in the form of an oligomer, it can be easily applied according to the user's reaction conditions. Furthermore, it has the advantage of producing reproducible physical properties of the final product. The HTEOS may generally 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 prepared by condensing TEOS, and the oligomer may be partially hydrated.

[0122] The above silica precursor composition can impart elasticity to the aerogel structure and increase pore strength by further including a silicate containing a hydrophobic group, and can also induce hydrophobicity within the aerogel matrix. In the present invention, the silicate containing the hydrophobic group is not limited in type as long as it is an alkyl silane compound containing a silane functional group capable of reacting with an alkyl group that induces hydrophobicity and a -Si-O- functional group of the wet gel. Non-limiting examples include one or more selected from the group consisting of methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDEOS), ethyltriethoxysilane (ETES), and phenyltriethoxysilane (PTES). The above alkyl silane compound may be methyltriethoxysilane (MTES), but is not limited thereto.

[0123] When the silica precursor composition contains the silicate containing the hydrophobic group, it may be included with the tetraalkyl silicate in a molar ratio of 2:98 to 98:2 (molar ratio of silicate containing the hydrophobic group to tetraalkyl silicate), and preferably in a molar ratio of 5:95 to 40:60. Within this range, the thermal insulation performance and hydrophobicity of the aerogel can be simultaneously secured with high efficiency.

[0124] The silica concentration of the above silica precursor composition is 10 kg / m³ 3 up to 100 kg / m² 3 , 20 kg / m 3 up to 80 kg / m² 3 , 30 kg / m 3 Up to 70 kg / m² 3 , 30 kg / m 3 up to 60 kg / m² 3 , or 35 kg / m² 3 Up to 45 kg / m 3 It may be, but is not limited thereto. In the present invention, the silica concentration is the concentration of silica contained in the silica precursor relative to the silica precursor composition, and can be appropriately adjusted by varying the content of the silica precursor, organic solvent, and water.

[0125] The above silica precursor may be used in an amount such that the silica content contained in the silica sol is 0.1% by weight to 30% by weight, but is not limited thereto. If the silica content satisfies the above range, it is desirable in terms of securing excellent mechanical properties, particularly flexibility, of the aerogel composite while also having an improved thermal insulation effect.

[0126] The above polar organic solvent may include alcohols, and specific examples 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, but other solvents known to those skilled in the art may also be used without limitation. In the present invention, among these, the polar organic solvent may be a monohydric alcohol having 1 to 6 carbon atoms, such as methanol, ethanol, isopropanol, butanol, etc., such as ethanol, when considering miscibility with water and aerogel.

[0127] 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 while promoting the surface modification reaction.

[0128] When preparing the above-described silica precursor composition, the silica precursor and the organic solvent may be mixed in a weight ratio of 1:0.1 to 5 or 1:0.5 to 3, but are not limited thereto. However, if the silica precursor composition contains a silicate containing hydrophobic groups, the mixture of the silicate containing hydrophobic groups and the tetraalkyl silicate and the organic solvent may be mixed in the above weight ratio.

[0129] In addition, the silica precursor composition may be prepared by mixing the silica precursor and water in a molar ratio of 1:0.5 to 10, 1:1 to 8, or 1:3 to 6, but is not limited thereto. However, if the silica precursor composition contains a silicate containing a hydrophobic group, a mixture of the silicate containing a hydrophobic group and a tetraalkyl silicate and water may be mixed in the above molar ratio.

[0130] The above silica precursor composition may further include an acid catalyst, specifically, when an alkoxysilane compound other than a hydrolysate is used as a precursor, the acid catalyst may further include an acid catalyst. In this case, any acid catalyst that lowers the pH to 3 or lower can be used without limitation, and examples include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, or acetic acid. In this case, the acid catalyst may be added in an amount that lowers the pH of the sol to 3 or lower, or it may be added in the form of an aqueous solution dissolved in an aqueous solvent.

[0131] 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 solution), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), methylamine, ethylamine, isopropylamine, monoisopropylamine, diethylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, choline, monoethanolamine, diethanolamine, 2-aminoethanol, 2-(ethylamino)ethanol, 2-(methylamino)ethanol, N-methyl diethanolamine, dimethylaminoethanol, diethylaminoethanol, nitrilotriethanol, It may be 2-(2-aminoethoxy)ethanol, 1-amino-2-propanol, triethanolamine, monopropanolamine, dibutanolamine, pyridine, or a combination thereof, but is not limited thereto.

[0132] The above base catalyst may be included in an amount such that the pH of the sol becomes 5 to 9. If the pH of the sol falls outside this range, gelation may not be easy or the gelation rate may become excessively slow, potentially leading to reduced processability. Additionally, since the base may precipitate when added in a solid state, it may be preferable to add it in a solution diluted by an aqueous solvent or the aforementioned organic solvent. In this case, the dilution ratio of the base catalyst and the organic solvent, specifically the alcohol, may be 1:4 to 1:100 by volume, but is not limited thereto.

[0133] To prepare the silica sol, the silica precursor composition and the catalyst composition may be mixed in a volume ratio of 1:0.01 to 10.0, 1:0.01 to 5.0, or 1:0.01 to 2.0, but are not limited thereto.

[0134] If necessary, additional additives may be added to the silica sol. In this case, any known additives that can be added when manufacturing an aerogel may be used, and for example, additives such as opacifiers and flame retardants may be used.

[0135] The above additive may be added in an amount of 0.1% to 10% by weight, 0.1% to 7% by weight, 0.5% to 7% by weight, or 0.5% to 5% by weight with respect to the silica content of the aerogel, but is not limited thereto.

[0136] Gelation step of silica sol

[0137] After impregnating the above-mentioned material with silica sol, the silica sol can be gelated.

[0138] The above impregnation process is a process that allows the catalytic silica sol to penetrate into the internal pores of the substrate. It can be performed by introducing the catalytic silica sol and the substrate into a reaction vessel, or by spraying the catalytic silica sol onto the substrate moving on a conveyor belt according to a roll-to-roll process. At this time, to improve the bonding between the substrate and the silica sol, the substrate can be lightly pressed to ensure sufficient impregnation. Subsequently, the material can be pressed to a certain thickness under a constant pressure to remove excess silica sol, thereby reducing the drying time.

[0139] The temperature of the silica sol in the reaction vessel may be 1 to 40 ℃, 20 to 40 ℃, 25 to 40 ℃, 30 to 40 ℃, or 35 to 45 ℃. It is preferable that the temperature of the silica sol in the reaction vessel satisfies the above range, as the aforementioned viscosity range of the catalyzed sol can be achieved more easily and the desired level of viscosity range can be satisfied even with a relatively short residence time.

[0140] It is preferable to impregnate the substrate with the above-mentioned catalytic silica sol in a volume ratio of 0.1 to 10:1 (catalytic silica sol:substrate), 0.1 to 1:1, 0.3 to 1:1, 0.5 to 1:1, or 0.6 to 1:1 to increase hydrophobicity and matrix strength, but is not limited thereto.

[0141] The silica sol impregnated in the substrate can be gelled simultaneously with the impregnation process of the silica sol or sequentially after the impregnation process.

[0142] The substrate impregnated with the above-mentioned catalysted sol can be gelled on a moving element such as a conveyor belt.

[0143] 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-like structure in which a specific polygon with an atomic arrangement of one or more types is connected, or a structure that forms a three-dimensional skeletal structure by sharing vertices, edges, faces, etc. of a specific polyhedron.

[0144] The above gelation may be performed under an atmosphere temperature of 20 to 40 ℃, 20 to 30 ℃, 25 to 40 ℃, 30 to 40 ℃, or 35 to 40 ℃, but is not limited thereto.

[0145] The above gelation may be performed for about 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, but can be appropriately controlled by considering the gelation temperature, the amount of silica sol, etc.

[0146] Aging stage of the gelled wet gel complex

[0147] If necessary, an aging step may be further included to allow the wet gel composite obtained by gelation as described above to be left at an appropriate temperature to allow the chemical change to be fully completed. In the aging step, the network structure formed by gelation can be formed more firmly, thereby improving the mechanical stability of the aerogel composite.

[0148] The above aging step can be performed by leaving the gelled wet gel complex as is at an appropriate temperature, or by adding a cross-linking promoting compound.

[0149] During the above aging step, in the presence of the above wet gel complex, a solution of a base catalyst such as sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), triethylamine, or pyridine diluted in an organic solvent to a concentration of 1 to 10 weight percent may be added. In this case, Si-O-Si bonds within the aerogel are induced to the maximum extent, making the network structure of the silica gel more robust and facilitating the maintenance of the pore structure during the subsequent drying process. At this time, the organic solvent may be the aforementioned alcohol, and specifically, may include ethanol.

[0150] In addition, by adding a mixed solution of an alkoxysilane compound and an alcohol during the aging step, an additional source of sol precursors as well as unreacted sol is provided, thereby inducing additional gelation in the silica gel network structure and further strengthening the gel structure. It is preferable to add a silicate containing a hydrophobic group as the alkoxysilane compound, as this allows for simultaneous strengthening of the aerogel matrix structure and hydrophobic modification of the surface / inside of the aerogel matrix. The alkoxysilane compound may be included in an amount of 0.5 to 9.5 parts by weight, 1.0 to 7 parts by weight, or 1.5 to 5.0 parts by weight relative to 100 parts by weight of the total aging solution.

[0151] The above alkoxysilane compounds are tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetrasecondary butyl orthosilicate, tetratertiary butyl orthosilicate, tetrahexyl orthosilicate, and tetracyclohexyl It may include one or more selected from the group consisting of tetracyclohexyl orthosilicate, tetradodecyl orthosilicate, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), trimethylchlorosilane (TMCS), ethyltriethoxysilane (ETES), dimethyldiethoxysilane (DMDEOS), and phenyltriethoxysilane.

[0152] In addition, the above alcohol may specifically be a monohydric alcohol such as methanol, ethanol, isopropanol, butanol, etc.; or a polyhydric alcohol such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and sorbitol, etc., and preferably may be a monohydric alcohol having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, butanol, etc., e.g. ethanol, but is not limited thereto.

[0153] The above aging step can be performed by leaving the product at a temperature of 30°C to 80°C, 40°C to 80°C, or 50°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 0.5 to 5 hours to strengthen the pore structure, and within this range, it is possible to prevent a decrease in productivity while preventing the loss of solvent due to evaporation, thereby preventing an increase in production costs.

[0154] In addition, the above aging step may be performed by first aging at 30°C to 80°C for 0.1 to 5 hours to strengthen the pore structure, and then by adding a solution in which the above-mentioned base catalyst is diluted in an organic solvent, and second aging may be performed 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.

[0155] In addition, the above aging step may be performed first under the conditions described above to strengthen the pore structure as well as to hydrophobize the pores, and then a mixed solution of an alkoxysilane compound and an alcohol may be added to perform a second aging step 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.

[0156] The above aging step may be performed in a separate reaction vessel after recovering the gelled wet gel complex, or it may be performed inside the reaction vessel where the gelling step was performed.

[0157] Surface modification step of aged wet gel complex

[0158] If necessary, a surface modification step may be further included to hydrophobize the surface of the wet gel complex obtained by gelation as described above or the aged wet gel complex in the presence of a surface modifier.

[0159] The above surface modifier may be any compound that hydrophobicizes the wet gel surface without limitation, such as a silane compound, a siloxane compound, a silanol compound, a silazane compound, or a combination thereof. Specific examples include silane compounds comprising trimethylchlorosilane (TMCS), dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), vinyltrimethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, dimethyldichlorosilane, 3-aminopropyltriethoxysilane, etc.; and siloxane compounds comprising polydimethylsiloxane, polydiethylsiloxane, or octamethylcyclotetrasiloxane, etc. Silanol-based compounds including trimethylsilanol, triethylsilanol, triphenylsilanol, and t-butyldimethylsilanol, etc.; silazane-based compounds including 1,2-diethyldisilazane, 1,1,2,2-tetramethyldisilazane, 1,1,3,3-tetramethyldisilazane, 1,1,1,2,2,2-hexamethyldisilazane (HMDS), 1,1,2,2-tetraethyldisilazane, or 1,2-diisopropyldisilazane, etc.; or a combination thereof, but not limited thereto. The surface modifier may be trimethylethoxysilane (TMES), but is not limited thereto.

[0160] The above surface modifier may be used as a solution diluted in an organic solvent. Here, the organic solvent may be an alcohol (organic solvent), and the surface modifier may be diluted to 1 to 15 volume% based on the total volume of the diluted solution.

[0161] In addition, the surface modification solution may be added in an amount of 10 to 130 volume%, 10 to 90 volume%, 30 to 90 volume%, or 50 to 90 volume% with respect to the wet gel composite for a sufficient surface modification effect, but is not limited thereto.

[0162] The surface modification step may be performed for 1 to 24 hours, preferably 6 to 12 hours, at a temperature of 50 to 90 ℃ or 50 to 80 ℃, but is not limited thereto.

[0163] drying stage

[0164] Next, the method may include a drying step of drying the surface-modified wet gel composite to obtain an aerogel composite.

[0165] The above drying is performed as a process that removes only the solvent while maintaining the pore structure of the aged gel, and can be performed, for example, by supercritical drying or atmospheric pressure drying.

[0166] The above supercritical drying process is performed using supercritical carbon dioxide. For example, a matured wet gel complex is placed into a supercritical drying reactor, and then liquid CO2 is filled and a solvent exchange process is performed to replace the alcohol solvent inside the wet gel with CO2. Afterward, the temperature is raised to 40 to 70 ℃ at a constant heating rate, e.g., 0.1 ℃ / min to 1 ℃ / min. Subsequently, a pressure greater than the pressure at which carbon dioxide reaches a supercritical state, e.g. 100 bar to 150 bar, is maintained to maintain the carbon dioxide in a supercritical state for a certain period of time, specifically 20 minutes to 1 hour. Generally, carbon dioxide reaches a supercritical state at a temperature of 31 ℃ and a pressure of 73.8 bar. An aerogel composite can be manufactured by maintaining the carbon dioxide at a constant temperature and constant pressure 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.

[0167] In addition, the atmospheric pressure drying process may be performed for 30 minutes to 4 hours according to conventional methods such as hot air drying or IR drying at a temperature of 70 to 200 ℃ and atmospheric pressure (1±0.3 atm), but is not limited thereto.

[0168] As described above, the carbon content on the surface of the aerogel composite can be reduced by applying heat treatment to the supercritical or atmospheric pressure dried aerogel composite at a temperature of 350 to 500°C for a short period of time, such as from 10 seconds to 5 minutes, from 10 seconds to 3 minutes, from 10 seconds to 1 minute, or from 30 seconds to 1 minute. However, if the heat treatment time is less than 10 seconds, the carbon content on the surface may not be reduced to the desired level, and an odor may still be generated when exposed to a high-temperature environment. If the heat treatment time exceeds 5 minutes, hydrophobicity within the aerogel matrix is ​​also removed, and as the hydrophobicity of the aerogel composite decreases, a decrease in thermal insulation performance due to the absorption of moisture from the air may occur.

[0169] The aerogel composite provided in the present invention can be usefully used as an insulating material, thermal insulation material, or non-combustible material for various industrial equipment piping or industrial furnaces, as well as for plant facilities for thermal insulation, thermal insulation, etc., and for aircraft, ships, automobiles, electronic devices, batteries, etc.

[0170]

[0171] According to another embodiment of the present invention, the invention relates to an insulating member comprising an aerogel composite provided in the present invention.

[0172] The above-described insulating member may include the aerogel composite described above and a supporting member located on at least one of the upper and lower surfaces of the aerogel composite.

[0173] Examples of the above-mentioned support members include film-type support members, sheet-type support members, thin-film support members, porous support members, etc.

[0174] The above film-like support member is formed by molding a polymer raw material into a thin film, and examples include organic films such as PET and polyimide, glass films, etc. (metal deposition films are also included).

[0175] The above sheet-like support member is formed from organic, inorganic, or metal fiber-like raw materials, and examples include paper, non-woven fabric (including glass mats), organic fiber fabric, glass cloth, etc.

[0176] The above-mentioned thin film support member is formed by molding a metal raw material into a thin film, and examples include aluminum foil, copper foil, etc.

[0177] The above porous support member has a porous structure made of organic, inorganic, or metal raw materials, and examples include porous organic materials (e.g., polyurethane foam), porous inorganic materials (e.g., zeolite sheets), porous metal materials (e.g., porous metal sheets, porous aluminum sheets), etc.

[0178] 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.

[0179] The above-mentioned insulating member can also be applied for use as an insulating material, thermal insulation material, or non-combustible material in the construction, aviation, automotive, battery, home appliance, semiconductor, and industrial equipment sectors.

[0180] The present invention is not limited thereto, but may include the following embodiments as examples within the scope of the present invention:

[0181] 1. A material; and an aerogel composite comprising an aerogel having a plurality of open pores, wherein the aerogel composite comprises carbon (C), silicon (Si), and oxygen (O), and the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite is 2 or more and 3 or less.

[0182] 2. In the first embodiment, the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.9 or less.

[0183] 3. In at least one of the first and second embodiments, the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.85 or less.

[0184] 4. In at least one of the first to third embodiments, silicon may be included in an amount of 20 to 50 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0185] 5. In at least one of the first to fourth embodiments, silicon may be included in an amount of 30 to 50 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0186] 6. In at least one of the first to fifth embodiments, silicon may be included in an amount of 35 to 45 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0187] 7. In at least one of the first to sixth embodiments, oxygen may be included in an amount of 30 to 60 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0188] 8. In at least one of the first to seventh embodiments, oxygen may be included in an amount of 40 to 60 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0189] 9. In at least one of the first to eighth embodiments, oxygen may be included in an amount of 40 to 50 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0190] 10. In at least one of the first to ninth embodiments, carbon may be included in an amount of 5 to 30 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0191] 11. In at least one of the first to tenth embodiments, carbon may be included in an amount of 10 to 20 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0192] 12. In at least one of the first to eleventh embodiments, carbon may be included in an amount of 10 to 15 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0193] 13. In at least one of the first to twelfth embodiments, carbon may be included in an amount of 10 to 14.63 weight% when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%.

[0194] 14. In at least one of the first to thirteenth embodiments, when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%, silicon may be included in an amount of 20 to 50 weight%, oxygen in an amount of 30 to 60 weight%, and carbon in an amount of 5 to 30 weight%.

[0195] 15. In at least one of the first to fourth embodiments, when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%, silicon may be included in an amount of 20 to 50 weight%, oxygen in an amount of 30 to 60 weight%, and carbon in an amount of 5 to 30 weight%.

[0196] 16. In at least one of the first to fifteen embodiments, when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%, silicon may be included in an amount of 35 to 45 weight%, oxygen in an amount of 40 to 50 weight%, and carbon in an amount of 10 to 20 weight%.

[0197] 17. In at least one of the first to sixth embodiments, when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%, silicon may be included in an amount of 30 to 50 weight%, oxygen in an amount of 40 to 60 weight%, and carbon in an amount of 10 to 15 weight%.

[0198] 18. In at least one of the first to 17 embodiments, silicon may be included in an amount of 20 to 50 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0199] 19. In at least one of the first to eighteen embodiments, silicon may be included in an amount of 25 to 45 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0200] 20. In at least one of the first to 19 embodiments, oxygen may be included in an amount of 40 to 75 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0201] 21. In at least one of the first to 20 embodiments, oxygen may be included in an amount of 50 to 70 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0202] 22. In at least one of the first to 21st embodiments, carbon may be included in an amount of 1 to 20 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0203] 23. In at least one of the first to 22 embodiments, carbon may be included in an amount of 3 to 10 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0204] 24. In at least one of the first to 23 embodiments, when the total content of carbon, silicon, and oxygen is 100 wt% based on the total thickness of the aerogel composite, silicon may be included in an amount of 20 to 50 wt%, oxygen in an amount of 40 to 75 wt%, and carbon in an amount of 1 to 20 wt%.

[0205] 25. In at least one of the first to 24 embodiments, the ratio of the total carbon content to the total silicon content of the aerogel composite may be 0.05 or more and 0.30 or less.

[0206] 26. In at least one of the first to 25 embodiments, the ratio of the total carbon content to the total silicon content of the aerogel composite may be 0.05 or more and 0.25 or less.

[0207] 27. In at least one of the first to 26 embodiments, the ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite may be 0.9 or more and 2.0 or less.

[0208] 28. In at least one of the first to 27 embodiments, the ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite may be 0.95 or more and 1.70 or less.

[0209] 29. In at least one of the first to 28 embodiments, the ratio of the oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite may be 0.5 or more and 1.0 or less.

[0210] 30. In at least one of the first to 29 embodiments, the ratio of the oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite may be 0.6 or more and 0.9 or less.

[0211] 31. An aerogel composite comprising a substrate; and an aerogel comprising a plurality of open pores, wherein the aerogel composite comprises carbon (C), silicon (Si) and oxygen (O), and when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%, silicon may be included in an amount of 30 to 50 weight%, oxygen in an amount of 40 to 60 weight%, and carbon in an amount of 10 to 15 weight%.

[0212] 32. In the 31st embodiment, when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%, silicon may be included in an amount of 30 to 50 weight%, oxygen in an amount of 40 to 60 weight%, and carbon in an amount of 10 to 14.63 weight%.

[0213] 33. In at least one of the 31st and 32nd embodiments, silicon may be included in an amount of 20 to 50 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0214] 34. In at least one of the 31st to 33rd embodiments, silicon may be included in an amount of 25 to 45 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0215] 35. In at least one of the 31st to 34th embodiments, oxygen may be included in an amount of 40 to 75 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0216] 36. In at least one of the 31st to 35th embodiments, oxygen may be included in an amount of 50 to 70 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0217] 37. In at least one of the 31st to 36th embodiments, carbon may be included in an amount of 1 to 20 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0218] 38. In at least one of the 31st to 37th embodiments, carbon may be included in an amount of 3 to 10 weight% when the total sum of carbon, silicon, and oxygen content is 100 weight% based on the total thickness of the aerogel composite.

[0219] 39. In at least one of the 31st to 38th embodiments, when the total content of carbon, silicon, and oxygen is 100% by weight based on the total thickness of the aerogel composite, silicon may be included in an amount of 20 to 50% by weight, oxygen in an amount of 40 to 75% by weight, and carbon in an amount of 1 to 20% by weight.

[0220] 40. In at least one of the 31st to 39th embodiments, the ratio of the total carbon content to the total silicon content of the aerogel composite may be 0.05 or more and 0.30 or less.

[0221] 41. In at least one of the 31st to 40th embodiments, the ratio of the total carbon content to the total silicon content of the aerogel composite may be 0.05 or more and 0.25 or less.

[0222] 42. In at least one of the 31st to 41st embodiments, the ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite may be 0.9 or more and 2.0 or less.

[0223] 43. In at least one of the 31st to 42nd embodiments, the ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite may be 0.95 or more and 1.70 or less.

[0224] 44. In at least one of the 31st to 43rd embodiments, the ratio of the oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite may be 0.5 or more and 1.0 or less.

[0225] 45. In at least one of the 31st to 44th embodiments, the ratio of oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite may be 0.6 or more and 0.9 or less.

[0226] 46. ​​In at least one of the 31st to 45th embodiments, the aerogel composite comprises carbon (C), silicon (Si), and oxygen (O), and the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite is 2 or more and 3 or less.

[0227] 47. In at least one of the 31st to 46th embodiments, the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.9 or less.

[0228] 48. In at least one of the 31st and 47th embodiments, the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite may be 2 or more and 2.85 or less.

[0229] 49. In at least one of the 1st to 48th embodiments, the amount of trimethylethoxysilane (TMES), trimethylsilanol (TMS), or hexamethyldisiloxane (HMDSO) generated per unit weight of the aerogel composite when the aerogel composite is heated at a temperature of 150°C for 15 minutes may be 10 μg / g or less.

[0230] 50. In at least one of the 1st to 49th embodiments, the aerogel composite may have a moisture impregnation rate (weight%) represented by the following Formula 1 of 15 weight% or less:

[0231] [Equation 1]

[0232] Moisture impregnation rate (weight%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0233] In the above Equation 1, the weight of the specimen after impregnation refers to the weight of the aerogel composite specimen after impregnating it in distilled water at 21±2 ℃ for 15 minutes.

[0234] 51. In at least one of the first to fifthty embodiments, the moisture impregnation rate (weight%) of the aerogel composite represented by Formula 1 may be 11 weight% or less.

[0235] 52. In at least one of the first to fifth-fifth embodiments, the thickness of the aerogel composite may be 0.5 mm to 20 mm.

[0236] 53. In at least one of the 1st to 52nd embodiments, the density of the aerogel composite is 0.05 to 0.50 g / cm³ 3 It could be.

[0237] 54. In at least one of the first to fifth and third embodiments, the aerogel may comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

[0238] 55. In the 54th embodiment, the aerogel may comprise secondary aerogel particles formed by aggregating or combining multiple primary aerogel particles having a particle size greater than 0 and less than or equal to 5 nm.

[0239] 56. In at least one of the first to fifth embodiments, the substrate may include glass fibers.

[0240] 57. The invention relates to an insulating member comprising at least one aerogel composite of the first to fifth-sixth embodiments.

[0241] 58. In the 57th embodiment, the insulating member may further include a supporting member located on at least one of the upper and lower surfaces of the aerogel composite.

[0242]

[0243] The present invention will be explained in detail below through the following examples. However, the following examples are merely illustrative of the present invention, and the scope of the present invention is not limited by the following examples.

[0244]

[0245] Examples

[0246]

[0247] [Example 1] Preparation of an Aerogel Composite

[0248] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 1:9. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:5 and the silica precursor composition with ethanol in a weight ratio of 1:3. To promote hydrolysis, hydrochloric acid was added to the silica sol to lower its pH to 3 or lower, and the mixture was stirred for at least 6 hours. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with this catalytic sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber with the catalytic sol, ensuring that the fiber mat was impregnated with the catalytic silica sol in a volume ratio of 1:1 (catalytic silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalytic sol, passed over a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25 ℃. After gelation was complete, the mixture was stabilized at room temperature (25 ℃) for 10 minutes, followed by primary aging in a 70 ℃ oven for 30 minutes. Subsequently, a solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the gelled wet gel composite at 109% of the volume of the wet gel composite, followed by secondary aging in a 75 ℃ oven for 2 hours. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the wet gel composite at 90 vol% of the volume of the wet gel composite as a surface modifier, and surface modification was performed at a temperature of 75 ℃ for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor is raised to 70 ℃ over 1 hour and 20 minutes, and when 70 ℃ and 150 bar are reached, 0 for 20 minutes.The process of injecting and exhausting CO2 at a rate of 5 L / min and maintaining a stopped CO2 injection for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in an electric furnace at 500 °C under a normal air atmosphere for 30 seconds.

[0249]

[0250] [Example 2] Preparation of an Aerogel Composite

[0251] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 1:9. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:5 and the silica precursor composition with ethanol in a weight ratio of 1:2. To promote hydrolysis, hydrochloric acid was added to the silica sol to lower its pH to 3 or lower, and the mixture was stirred for at least 6 hours. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with this catalytic sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber with the catalytic sol, ensuring that the fiber mat was impregnated with the catalytic silica sol in a volume ratio of 1:1 (catalytic silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalytic sol, passed over a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25 ℃. After gelation was complete, the mixture was stabilized at room temperature (25 ℃) for 10 minutes, followed by primary aging in a 70 ℃ oven for 30 minutes. Subsequently, a 3.4 wt% tetraethyl orthosilicate (TEOS) solution (solvent: ethanol) was prepared and added to the gelled wet gel composite at 109% of the volume of the wet gel composite, followed by secondary aging in a 75 ℃ oven for 2 hours. A 10 vol% solution of trimethyl ethoxysilane (TMES) diluted in ethanol was added to the wet gel composite at 90 vol% of the volume of the wet gel composite as a surface modifier, and surface modification was performed at a temperature of 75 ℃ for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor is raised to 70 ℃ over 1 hour and 20 minutes, and when 70 ℃ and 150 bar are reached, 0 for 20 minutes.The process of injecting and exhausting CO2 at a rate of 5 L / min and maintaining a stopped CO2 injection for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in a 350 °C electric furnace under a normal air atmosphere for 30 seconds.

[0252]

[0253] [Example 3] Preparation of an Aerogel Composite

[0254] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 2:8. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:5 and the silica precursor composition with ethanol in a weight ratio of 1:2. To promote hydrolysis, hydrochloric acid was added to the silica sol to lower its pH to 3 or lower, and the mixture was stirred for at least 6 hours. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with this catalytic sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber with the catalytic sol, ensuring that the fiber mat was impregnated with the catalytic silica sol in a volume ratio of 1:1 (catalytic silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalytic sol, passed over a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. To the gelled wet gel composite, a solution of 2.4 wt% ammonia water (NH4OH) diluted in ethanol with a moisture content of 10 wt% was added as an aging solution at 109% based on the volume of the wet gel blanket, and aging was carried out at a temperature of 75°C for 1 hour. To the wet gel composite, a solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added as a surface modifier at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75°C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over 1 hour and 20 minutes, and when 70°C and 150 bar were reached, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge.CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in an electric furnace at 500°C in a normal air atmosphere for 1 minute.

[0255]

[0256] [Example 4] Preparation of an Aerogel Composite

[0257] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an acid was added to lower the pH of the silica precursor solution to 3 or lower, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:0.73 with the hydrated TEOS solution. To promote hydrolysis, hydrochloric acid was added to lower the pH of the silica sol to 3 or lower, and the mixture was stirred for at least 6 hours. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. After filling the impregnation tank with this catalyzed sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber with the catalyzed sol, ensuring that the catalyzed silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (catalyzed silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalyzed sol, passed over a conveyor belt at a constant speed and gelled. During this process, the ambient temperature on the conveyor belt was maintained at 25°C. After gelation was complete, the mixture was stabilized at room temperature (25°C) for 10 minutes, followed by a first aging process in a 70°C oven for 30 minutes. Subsequently, a solution of 4.5 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the gelled wet gel composite at 109% of the volume of the wet gel composite, followed by a second aging process in a 75°C oven for 2 hours. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the wet gel composite as a surface modifier at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected.Subsequently, the temperature inside the extractor was raised to 70°C over a period of 1 hour and 20 minutes. Upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Afterward, CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in an electric furnace at 400°C under a normal air atmosphere for 1 minute.

[0258]

[0259] [Example 5] Preparation of an Aerogel Composite

[0260] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an acid was added to lower the pH of the silica precursor solution to 3 or lower, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:1 with the hydrated TEOS solution. To promote hydrolysis, hydrochloric acid was added to lower the pH of the silica sol to 3 or lower, and the mixture was stirred for at least 6 hours. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. After filling the impregnation tank with this catalyzed sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber, ensuring that the catalyzed silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (catalyzed silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalyzed sol, passed over a conveyor belt at a constant speed and gelled. During this process, the ambient temperature on the conveyor belt was maintained at 25°C. After gelation was complete, the mixture was stabilized at room temperature (25°C) for 10 minutes, followed by a first aging process in a 70°C oven for 30 minutes. Subsequently, a solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the gelled wet gel composite at 109% of the volume of the wet gel composite, followed by a second aging process in a 75°C oven for 2 hours. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the wet gel composite as a surface modifier at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected.Subsequently, the temperature inside the extractor was raised to 70°C over a period of 1 hour and 20 minutes. Upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Afterward, CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in a 400°C electric furnace under a normal air atmosphere for 30 seconds.

[0261]

[0262] [Comparative Example 1] Preparation of an aerogel composite

[0263] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a 1:1 molar ratio. A silica sol was prepared by mixing the silica precursor composition with water in a 1:5 molar ratio and the silica precursor composition with ethanol in a 1:2 weight ratio. To promote hydrolysis, hydrochloric acid was added to the silica sol to lower the pH to 3 or lower, and the mixture was stirred for at least 6 hours. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a 99:1 volume ratio with the silica sol. After filling an impregnation tank with this catalytic sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber with the catalytic sol, ensuring that the fiber mat was impregnated with the catalytic silica sol in a 1:1 volume ratio (catalytic silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalytic sol, passed over a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. To the gelled wet gel composite, a solution of 2.4 wt% ammonia water (NH4OH) diluted in ethanol with a moisture content of 10 wt% was added as an aging solution at 109% based on the volume of the wet gel blanket, and aging was carried out at a temperature of 75°C for 1 hour. To the wet gel composite, a solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added as a surface modifier at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75°C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over 1 hour and 20 minutes, and when 70°C and 150 bar were reached, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge.CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in an electric furnace at 500°C in a normal air atmosphere for 10 minutes.

[0264]

[0265] [Comparative Example 2] Preparation of an aerogel composite

[0266] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 1:9. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:5 and the silica precursor composition with ethanol in a weight ratio of 1:2. To promote hydrolysis, hydrochloric acid was added to the silica sol to lower its pH to 3 or lower, and the mixture was stirred for at least 6 hours. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with this catalytic sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber with the catalytic sol, ensuring that the fiber mat was impregnated with the catalytic silica sol in a volume ratio of 1:1 (catalytic silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalytic sol, passed over a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. To the gelled wet gel composite, a solution of 4.5 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was added as an aging solution at 109 volume% based on the volume of the wet gel blanket, and aging was carried out at a temperature of 75°C for 1 hour. To the wet gel composite, a solution of trimethylethoxysilane (TMES) diluted in ethanol (10 volume%) was added as a surface modifier at 90 volume% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75°C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over 1 hour and 20 minutes, and when 70°C and 150 bar were reached, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge.CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in an electric furnace at 450°C in a normal air atmosphere for 30 minutes.

[0267]

[0268] [Comparative Example 3] Preparation of an aerogel composite

[0269] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an acid was added to lower the pH of the silica precursor solution to 3 or lower, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:0.73 with the hydrated TEOS solution. To promote hydrolysis, hydrochloric acid was added to lower the pH of the silica sol to 3 or lower, and the mixture was stirred for at least 6 hours. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. After filling the impregnation tank with this catalyzed sol, the fiber (glass fiber mat, 3 mm) was passed through as a substrate to infiltrate the fiber with the catalyzed sol, ensuring that the catalyzed silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (catalyzed silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalyzed sol, passed over a conveyor belt at a constant speed and gelled. During this process, the ambient temperature on the conveyor belt was maintained at 25°C. To the gelled wet gel composite, a solution of 2.4 wt% ammonia water (NH4OH) diluted in ethanol with a moisture content of 10 wt% was added as an aging solution at 109% based on the volume of the wet gel blanket, and aging was carried out at a temperature of 75°C for 1 hour. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the wet gel composite as a surface modifier at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 °C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70 °C over 1 hour and 20 minutes, and upon reaching 70 °C and 150 bar, 0.The process of injecting and exhausting CO2 at a rate of 5 L / min and maintaining a stopped CO2 injection for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, CO2 was vented over a period of 2 hours. The dried hydrophobic silica aerogel composite was heat-treated in an electric furnace at 500 °C under a normal air atmosphere for 5 seconds.

[0270]

[0271] [Comparative Example 4] Preparation of an aerogel composite

[0272] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 1:9. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:5 and the silica precursor composition with ethanol in a weight ratio of 1:3. To promote hydrolysis, hydrochloric acid was added to the silica sol to lower its pH to 3 or lower, and the mixture was stirred for at least 6 hours. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with this catalytic sol, the sol was passed through a fiber (glass fiber mat, 3 mm) as a substrate to infiltrate the fiber with the catalytic sol, ensuring that the fiber mat was impregnated with the catalytic silica sol in a volume ratio of 1:1 (catalytic silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalytic sol, passed over a conveyor belt at a constant speed and gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the gelled wet gel composite as a surface modifier at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75°C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over 1 hour and 20 minutes; upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Subsequently, a hydrophobic silica aerogel composite was prepared by venting CO2 over a period of 2 hours.

[0273]

[0274] [Comparative Example 5] Preparation of an aerogel composite

[0275] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an acid was added to lower the pH of the silica precursor solution to 3 or lower, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:0.73 with the hydrated TEOS solution. To promote hydrolysis, hydrochloric acid was added to lower the pH of the silica sol to 3 or lower, and the mixture was stirred for at least 6 hours. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. After filling the impregnation tank with this catalyzed sol, a fiber (glass fiber mat, 3 mm) was passed through as a substrate to infiltrate the fiber with the catalyzed sol, ensuring that the catalyzed silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (catalyzed silica sol: fiber). The fiber, having passed through the impregnation tank and infiltrated with the catalyzed sol, passed over a conveyor belt at a constant speed and gelled. During this process, the ambient temperature on the conveyor belt was maintained at 25°C. To the gelled wet gel composite, a solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was added as an aging solution at 109% based on the volume of the wet gel blanket, and aging was carried out at a temperature of 75°C for 1 hour. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the wet gel composite as a surface modifier at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 °C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70 °C over 1 hour and 20 minutes, and upon reaching 70 °C and 150 bar, 0.The process of injecting and exhausting CO2 at a rate of 5 L / min and maintaining a stopped CO2 injection for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, CO2 was vented over a period of 2 hours. After supercritical drying was completed, the hydrophobic silica aerogel composite was prepared by further drying for 1 hour at 150 ℃ and atmospheric pressure.

[0276]

[0277] [Experimental Example 1] Component Analysis of Aerogel Composite

[0278] 1. Analysis of Silicon (Si), Carbon (C), and Oxygen (O) Content in the Entire Aerogel Composite

[0279] The content of Si, C, and O elements contained in the aerogel composites of Examples 1 to 5 and Comparative Examples 1 to 5 was analyzed through X-ray fluorescence analysis (XRF). First, five circular specimens with a diameter of approximately 30 mm were obtained from each of the aerogel composites of the Examples and Comparative Examples. More specifically, four specimens were obtained by positioning the exact center of a rectangular aerogel composite measuring 60 cm x 12 cm at a distance of 10 cm from each corner toward the center, and one specimen was obtained by positioning the exact center of the aerogel composite at the exact center of the specimen. A WD-XRF (Rigaku ZSX Primus IV) instrument was used for XRF analysis, and the content of Si, C, and O elements was analyzed after placing the specimens in the instrument's dedicated holder. At this time, the content percentage (weight%) of each element was calculated by making the total content of Si, C, and O elements 100 weight%.

[0280] 2. Analysis of Silicon (Si), Carbon (C), and Oxygen (O) Content on the Surface of the Aerogel Composite

[0281] The content of Si, C, and O elements was analyzed in a thickness region of approximately 10 nm depth from the surface of the aerogel composite using X-ray Photoelectron Spectroscopy (XPS). First, the specimen used for the XRF analysis in 1. above was cut into a square specimen with dimensions of 10 mm x 10 mm. An X-ray Photoelectron Spectrometer (model name: Nexsa, manufacturer: Thermo Fisher Scientific Inc.) was used for the XPS analysis, and monochromatic Al Kα (1486.6 eV) was used as the X-ray source. For quantitative analysis, the Shirley Peak background, ALTHERMO1 Sensitivity factor, and TPP-2M Energy compensation factor were applied. The content of Si, C, and O elements present on the surface of the aerogel composite was obtained as the atomic percentage (at%) of each element relative to the total atomic weight using Avantage software, and then the weight percentage of each element was calculated by making the total content of Si, C, and O elements 100 weight%.

[0282] The content (wt%) of Si, C, and O elements based on the total thickness of the aerogel composite obtained through the XRF analysis above is shown in Table 1. In addition, the content (wt%) of Si, C, and O elements on the surface of the aerogel composite obtained through XPS analysis is shown in Table 2 below. Based on the results of Tables 1 and 2, the ratio of the carbon content on the surface of the aerogel composite to the carbon content based on the total thickness of the aerogel composite (carbon 표면 Content / Carbon 전체The content) was calculated and the results are shown in Table 3 below. However, the analysis results in Tables 1 and 2 are based on the average values ​​calculated from the results measured for 5 specimens of each aerogel composite, and are rounded to the third decimal place.

[0283] XRF Analysis Results Classification Content (Wet%) OCSi Example 1 53.50 3.97 42.53 Example 2 53.66 4.95 41.39 Example 3 59.736 76 33.51 Example 4 54.79 6.89 38.32 Example 5 69.36 5.00 25.64 Comparative Example 1 62.88 3.36 33.76 Comparative Example 2 56.82 3.44 39.74 Comparative Example 3 56.33 4.08 39.59 Comparative Example 4 54.82 4.26 40.92 Comparative Example 5 55.19 4.83 39.98

[0284] XPS Analysis Results Classification Content (Wet%) OCCi Example 1 47.6 210.5 44 1.84 Example 2 44.8 213.9 74 1.21 Example 3 47.8 914.0 838.03 Example 4 43.1 614.6 34 2.21 Example 5 43.9 114.0 34 2.06 Comparative Example 1 48.8 85.1 34 5.99 Comparative Example 2 49.9 36.1 54 3.92 Comparative Example 3 42.0 915.1 14 2.80 Comparative Example 4 42.5 16.3 14 1.19 Comparative Example 5 47.4 218.0 334.55

[0285] Classification Surface Carbon / Total Carbon Surface Silicon / Total Silicon Surface Oxygen / Total Oxygen Example 1 2.65 50.98 40.890 Example 2 2.82 20.99 60.835 Example 3 2.08 31.13 50.802 Example 4 2.12 31.10 20.788 Example 5 2.80 61.64 0.633 Comparative Example 1 1.52 71.36 20.777 Comparative Example 2 1.78 81.10 50.879 Comparative Example 3 3.70 31.08 10.747 Comparative Example 4 3.82 91.00 70.775 Comparative Example 5 3.73 30.86 40.859

[0286] As shown in Tables 1 to 3 above, in the aerogel composites of Examples 1 to 5, the ratio of carbon content on the surface to carbon content based on the total thickness of the aerogel composite (surface carbon / total carbon) was 2 or more and 3 or less, whereas in the aerogel composites of Comparative Examples 1 and 2, the ratio was low at 1.8 or less, and in the aerogel composites of Comparative Examples 3 to 5, a high value of 3.7 or more was shown.

[0287]

[0288] [Experimental Example 2] Analysis of Volatile Organic Compound (VOC) Generation

[0289] To compare the amount of volatile organic compounds generated from the aerogel composites prepared in Examples 1 to 5 and Comparative Examples 1 to 5, Gas Chromatography / Mass Spectrometry-Thermal Desorption (GC / MS-TD) was performed under high temperature exposure. The conditions for this GC / MS-TD analysis are as follows:

[0290] - Sample: 50 mg

[0291] - Temperature and time: 150 ℃, 15 minutes

[0292] - GC Oven: 40 ℃ (5 min) - Heat up (10 ℃ / min) - 250 ℃ (10 ℃ / min)

[0293] - Column: DB-624

[0294] - Toluene standard solution

[0295] As shown in Equation 1 below, the emission amount (µg / g) of volatile organic compounds was calculated according to Equation 2 below. The result of the above thermal desorption gas chromatography (Gas Chromatography / Mass Spectrometry-Thermal Desorption, GC / MS-TD) analysis is the value (µg / g) calculated based on the peak area relative to the above toluene standard solution.

[0296] [Equation 2]

[0297] VOC compound = [(A compound / A std ) x C std ] / W sample

[0298] VOC compound : VOC values ​​of individual substances generated from the measured sample (µg / g)

[0299] A compound : Chromatogram area of ​​individual substance peaks in the measured sample

[0300] A std : Peak area of ​​toluene standard solution

[0301] C std : Mass of toluene injected using toluene standard solution (µg)

[0302] W sample : Weight of the sample to be measured (g)

[0303] Classification Amount Generated (μg / g) EtOH™ EST MSH MD SO Example 1 14 60 < 10 < 10 < 10 Example 2 17 80 < 10 < 10 < 10 Example 3 13 20 < 10 < 10 < 10 Example 4 11 30 < 10 < 10 < 10 Example 5 14 10 < 10 < 10 < 10 Comparative Example 1 < 10 < 10 < 10 < 10 Comparative Example 2 < 10 < 10 < 10 < 10 Comparative Example 3 21 80 30 20 20 Comparative Example 4 28 70 50 30 20 Comparative Example 5 23 00 50 30 20

[0304] As shown in Table 4 above, the aerogel composites prepared in Examples 1 to 5 and Comparative Examples 1 and 2, in which the ratio of surface carbon content to total carbon content was low at 3 or less, showed very low levels of trimethylethoxysilane (TMES), trimethylsilanol (TMS), and hexamethyldisiloxane (HMDSO), which are known to cause odors, all of which were less than 10 μg / g. However, in the aerogel composites of Comparative Examples 3 to 5, in which the ratio exceeded 3, it was observed that trimethylethoxysilane (TMES) and trimethylsilanol (TMS) were generated at approximately 30 μg / g, and hexamethyldisiloxane (HMDSO) at approximately 20 μg / g.

[0305]

[0306] [Experimental Example 3] Evaluation of Hydrophobicity of Aerogel Composite

[0307] To evaluate the internal hydrophobicity of the aerogel composites prepared in Examples 1 to 5 and Comparative Examples 1 to 5, the cross-sectional water repellency was measured for specimens measuring 10 mm x 10 mm according to ASTM C1511. Specifically, for each aerogel composite of the examples and comparative examples, five specimens of the said size were prepared in the same manner as in 1. of Experimental Example 1. After floating the specimens on distilled water at 21±2 ℃, a 6.4 mm mesh screen was lowered 127 mm below the water surface (impregnation). After 15 minutes, the mesh screen was removed, and when the specimens floated to the surface, the specimens were picked up with a clamp and suspended vertically for 60±5 seconds. Subsequently, the weight of the specimens before and after impregnation was measured, and the water impregnation rate was measured according to Equation 1 below. The results were presented as the average value of the water impregnation rates measured for the five specimens, rounded to the first decimal place.

[0308] [Equation 1]

[0309] Moisture impregnation rate (weight%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100

[0310] Classification Moisture Impregnation Rate (Weight%) Example 1 6.6 Example 2 5.0 Example 3 11 Example 4 6.5 Example 5 5.4 Comparative Example 1 153 Comparative Example 2 93 Comparative Example 3 4.8 Comparative Example 4 4.1 Comparative Example 5 4.5

[0311] As shown in Table 5 above, it was observed that the internal hydrophobicity of the aerogel composites of Examples 1 to 5 was high, with a moisture impregnation rate of 11 wt% or less. However, the aerogel composites of Comparative Examples 1 and 2 had very high moisture impregnation rates of 153 wt% and 93 wt%, respectively, indicating that the internal hydrophobicity was very low. From the experimental results above, the aerogel composite according to the present invention, in which the ratio of the carbon content on the surface to the total carbon content based on thickness is 2 or more and 3 or less, has a low carbon content on the surface, thereby suppressing the generation of volatile organic compounds such as trimethylethoxysilane (TMES), trimethylsilanol (TMS), and hexamethyldisiloxane (HMDSO) that can cause odors, while maintaining high internal hydrophobicity of the aerogel composite, which can suppress the problem of reduced thermal insulation performance due to moisture in the air during actual use.

[0312] Specific parts of the present invention have been described in detail above. It is evident to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

[0313] The present invention relates to an aerogel composite and its application as an insulating material.

Claims

1. A material; and an aerogel composite comprising an aerogel having a plurality of open pores, The above aerogel composite comprises carbon (C), silicon (Si), and oxygen (O), and An aerogel composite in which, when the total sum of the carbon, silicon, and oxygen content in the aerogel composite is 100 weight%, the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite is 2 or more and 3 or less.

2. In Paragraph 1, An aerogel composite in which the ratio of the carbon content on the surface of the aerogel composite to the total carbon content of the aerogel composite is 2 or more and 2.85 or less.

3. In Paragraph 1, An aerogel composite comprising, when the total content of carbon, silicon, and oxygen on the surface of the aerogel composite is 100 weight%, silicon in an amount of 20 to 50 weight%, oxygen in an amount of 30 to 60 weight%, and carbon in an amount of 5 to 30 weight%.

4. In Paragraph 1, An aerogel composite comprising, when the total content of carbon, silicon, and oxygen is 100 weight% based on the total thickness of the aerogel composite, silicon in an amount of 20 to 50 weight%, oxygen in an amount of 40 to 75 weight%, and carbon in an amount of 1 to 20 weight%.

5. In Paragraph 4, An aerogel composite having a ratio of total carbon content to total silicon content of 0.05 or more and 0.30 or less.

6. In Paragraph 1, An aerogel composite in which the ratio of silicon content on the surface of the aerogel composite to the total silicon content of the aerogel composite is 0.9 or more and 2.0 or less.

7. In Paragraph 1, An aerogel composite in which the ratio of oxygen content on the surface of the aerogel composite to the total oxygen content of the aerogel composite is 0.5 or more and 1.0 or less.

8. In Paragraph 1, An aerogel composite having an amount of trimethylethoxysilane (TMES), trimethylsilanol (TMS), or hexamethyldisiloxane (HMDSO) generated per unit weight of the aerogel composite when heated at a temperature of 150°C for 15 minutes of 10 μg / g or less.

9. In Paragraph 1, The above aerogel composite is an aerogel composite having a moisture impregnation rate (weight%) represented by the following Formula 1 of 15 weight% or less: [Equation 1] Moisture impregnation rate (weight%) = {(Weight of specimen after impregnation - Weight of specimen before impregnation) / (Weight of specimen before impregnation)} X 100 In the above Equation 1, the weight of the specimen after impregnation refers to the weight of the aerogel composite specimen after impregnating it in distilled water at 21±2 ℃ for 15 minutes.

10. In Paragraph 1, An aerogel composite having a thickness of 0.5 mm to 20 mm.

11. In Paragraph 1, The density of the above aerogel composite is 0.05 to 0.50 g / cm³ 3 Phosphorus, aerogel complex.

12. In Paragraph 1, The above aerogel is an aerogel composite comprising silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

13. In Paragraph 1, The above aerogel is an aerogel composite comprising secondary aerogel particles formed by the aggregation or bonding of multiple primary aerogel particles having a particle size greater than 0 and less than or equal to 5 nm.

14. In Paragraph 1, The above aerogel composite has a compressive strength of 20 kPa to 80 kPa at 10% strain and a tensile strength of 30 N / cm 2 up to 60 N / cm 2 Aerogel composite that is.

15. An insulating member comprising an aerogel composite of any one of claims 1 to 14.

16. In Paragraph 15, The insulating member further comprises a supporting member positioned on at least one of the upper and lower surfaces of the aerogel composite.