Aerogel composite

Abstract

A hydrophobic silica aerogel blanket, in which a hydrophobic silica aerogel is formed on fibers, is a functional thermal insulating material that prevents corrosion caused by moisture, and is widely used in construction or industrial fields. In addition, the hydrophobic silica aerogel blanket can be usefully employed as a thermal insulating material or a thermal retention material for aircrafts, ships, vehicles, batteries, and the like. However, when the silica aerogel blanket is applied for the purpose as described above, it may be subjected to a pressurized environment due to continuous thermal expansion or the like of a neighboring device, or high pressure is applied from the surroundings during the installation of an aerogel thermal insulating material, and thus, the aerogel structure collapses, resulting in a substantial decrease in thermal insulating performance. Therefore, the aim of the present invention is to provide an aerogel composite capable of constantly maintaining thermal insulating performance without significant degradation of thermal insulating performance even when exposed to a pressurized environment.

Description

Aerogel composites

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

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0042132, filed March 27, 2024, and U.S. Patent Application No. 18 / 909,415, filed October 8, 2024, the entire contents of which are incorporated herein by reference.

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

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

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

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

[0007] In particular, hydrophobic silica aerogel blankets, which form hydrophobic silica aerogel on fibers, are widely used in construction and industrial sites as functional insulating materials that prevent corrosion due to moisture, and can also be usefully used as insulating or heat-retaining materials for aircraft, ships, automobiles, batteries, etc. However, when such silica aerogel blankets are applied for the above-mentioned purposes, there was a problem in that the insulating properties were significantly reduced, such as when a pressurized environment was provided due to continuous thermal expansion from a neighboring device, or when a large pressure was applied from the surroundings during the installation of the aerogel insulation, causing the aerogel structure to collapse.

[0008] One object of the present invention is to provide an aerogel composite whose insulating properties can be maintained at a constant level without significantly deteriorating even when exposed to a pressurized environment.

[0009] However, the technical problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

[0010] According to one embodiment of the present invention, there is provided an aerogel composite comprising a substrate comprising a plurality of discrete fibers and voids between the fibers; and a plurality of aerogel particles positioned on the fibers and in the voids between the fibers, the aerogel having a network structure including one or more pores.

[0011] 150 N / cm in the thickness direction for the above aerogel composite 2 When pressure is applied, the volume ratio of the voids between the aerogel and the discrete fibers including pores per unit volume of the aerogel composite is 0.85 times or more and 1 times or less than that before applying the pressure.

[0012] The volume ratio of the voids between the aerogel and the discrete fibers per unit volume of the aerogel composite may be 88 to 98%.

[0013] The ratio of the total volume of the fibers per unit volume of the aerogel composite may be 2 to 12%.

[0014] 300 N / cm in the thickness direction for the above aerogel composite 2 When pressure is applied, the volume ratio of the voids between the aerogel and the discrete fibers including pores per unit volume of the aerogel composite may be 0.80 times or more and 1 times or less than that before applying the pressure.

[0015] 300 N / cm in the thickness direction for the above aerogel composite 2 When a pressure of , the volume ratio of the voids between the aerogel and the discrete fibers containing pores per unit volume of the aerogel composite is 150 N / cm 2 When pressure is applied, it may be 0.89 times or more and 1 times or less.

[0016] 150 N / cm in the thickness direction of the above aerogel composite 2 More than 300 N / cm 2 When the pressure below is applied, the heat transmittance after compression may be less than twice the heat transmittance before compression.

[0017] 150 N / cm for the cross section of the above aerogel composite 2 When pressure is applied, the thermal transmittance after compression may be 1.8 times or less than the thermal transmittance before compression, or may be more than 1 time and less than 1.5 times.

[0018] 300 N / cm for the cross section of the above aerogel composite 2 When pressure is applied, the thermal transmittance after compression may be less than or equal to 2 times the thermal transmittance before compression, or more than 1 time and less than or equal to 1.8 times the thermal transmittance before compression.

[0019] 150 N / cm for the cross section of the above aerogel composite 2 and 300 N / cm 2 When pressure is applied, the thermal transmittance after compression may be more than 1 time and less than 2 times the thermal transmittance before compression.

[0020] 150 N / cm for the above aerogel composite 2 and 300 N / cm 2 When compressed by applying pressure, the thermal transmittance before and after compression can satisfy the following equation 2:

[0021] [Formula 2]

[0022] {(Thermal transmittance before and after compression (a)) - (Average of thermal transmittances before and after compression (b))} = (Average of thermal transmittances before and after compression (b)) XA

[0023] In the above equation 2, the thermal transmittance (a) before and after compression is 0 N / cm in the thickness direction of the aerogel composite. 2 , 150 N / cm 2 or 300 N / cm 2 It means the thermal transmittance obtained after compression by the century, and the average value (b) of the thermal transmittances before and after compression is the thermal transmittance of the unpressurized aerogel composite and 150 N / cm for the aerogel composite. 2 and 300 N / cm 2 It means the average value of the thermal transmittance obtained after compression by the century, and the above A can be a real number of - 0.30 to + 0.30, or a real number of - 0.25 to + 0.25.

[0024] 150 N / cm for the above aerogel composite 2 or 300 N / cm 2 When pressure is applied, the rate of change in the thermal transmittance after compression per unit applied pressure (B) obtained after compression can satisfy the following equation 3:

[0025] [Formula 3]

[0026] B = │(Thermal transmittance after compression at pressure x - Thermal transmittance after compression at pressure y) / (x - y)│

[0027] In the above equation 3, x is 150 N / cm 2 or 300 N / cm 2 is the pressure of , y is 0, and B is greater than or equal to 0 and 2.0 X 10 -2 The following is a mistake.

[0028] The above x is 150 N / cm 2 , y is 0, and B is greater than or equal to 0 and 1.5 X 10 -2 The following may be a mistake:

[0029] The above x is 300 N / cm 2 , y is 0, and the above B is greater than or equal to 0 and 1.0 X 10 -2 The following may be a mistake:

[0030] The fiber substrate and the aerogel in the above aerogel composite may be included in a weight ratio of 1:0.4 to 2.

[0031] The density of the above aerogel composite is 0.15 to 0.35 g / cm 3 It could be.

[0032] According to another embodiment of the present invention, there is provided an insulating member comprising the aerogel composite of the present invention.

[0033] The above insulating member may further include a support member positioned on at least one of the upper and lower surfaces of the aerogel composite.

[0034] The aerogel composite provided in the present invention, when applied as an insulating material to batteries, electronic devices, automobiles, industrial devices, or structures, can maintain excellent levels of insulating properties without significantly reducing them even when pressure is applied to the aerogel composite due to expansion of various devices or structures located adjacent thereto or other causes, thereby causing compression deformation.

[0035] Figure 1 illustrates an example process of setting and extracting a segmentation area for analyzing the volume occupancy of fibers and the remaining portion within the aerogel composite using Dragonfly software after performing in-situ XRM analysis on the aerogel composite in Experimental Example 1.

[0036] Figure 2 illustrates an example process of segmenting fibers and the remaining portion excluding fibers within a segmented area according to contrast level using Dragonfly software in Experimental Example 1.

[0037] Figure 3 illustrates an example process of calculating the volume occupancy rate (volume ratio) of each region after dividing the fibers and the remaining portion excluding the fibers using Dragonfly software in Experimental Example 1.

[0038] According to one embodiment of the present invention, there is provided an aerogel composite comprising a fiber substrate; and an aerogel including one or more pores.

[0039] The above aerogel composite has a structure in which at least some of a plurality of aerogel particles are dispersed, preferably bonded, on the surface of a substrate including fibers, and at the same time, at least some of the plurality of aerogel particles are dispersed, preferably positioned, in the empty spaces between the fibers within the substrate. Examples of the substrate may include discrete fibers, films, sheets, nets, fibers, porous bodies, foams, non-woven fabrics, or laminates of two or more layers thereof. In addition, depending on the intended use, the surface may have surface roughness or may be patterned.

[0040] Specifically, the volume ratio of the remaining portion excluding the fibers per unit volume of the aerogel composite of the present invention, that is, the aerogel including pores, and the voids between the fibers may be comprised of 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, or 90% or more, and 98% or less, 97% or less, 96% or less, 95% or less, 94% or less, or 93% or less, and preferably 88 to 98%, or 90 to 95%. In the present specification, the voids refer to empty spaces between discrete fibers that are not filled with the aerogel.

[0041] The ratio of the volume of the fibers per unit volume of the aerogel composite may be comprised of 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, or 10% or more, and 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, or 10% or less, and preferably 2 to 12%, or 5 to 10%.

[0042] 150 N / cm in the thickness direction for the above aerogel composite 2When a pressure is applied, the volume ratio of the voids between the aerogel and the fibers including pores per unit volume of the aerogel composite may be 0.85 times or more, 0.86 times or more, 0.87 times or more, 0.88 times or more, 0.89 times or more, 0.90 times or more, 0.91 times or more, 0.92 times or more, 0.93 times or more, 0.94 times or more, or 0.95 times or more, and may be 1 time or less, 0.99 times or less, 0.98 times or less, 0.97 times or less, 0.96 times or less, 0.95 times or less, 0.94 times or less, 0.93 times or less, 0.92 times or less, 0.91 times or less, or 0.90 times or less. Preferably, it may be 0.85 times or more and 1 times or less, 0.85 times or more and 0.97 times or less, or 0.87 times or more and 0.97 times or less.

[0043] 300 N / cm in the thickness direction for the above aerogel composite 2 When pressure is applied, the volume ratio of the voids between the aerogel and the fibers including the pores per unit volume of the aerogel composite may be 0.80 times or more, 0.81 times or more, 0.82 times or more, 0.83 times or more, 0.84 times or more, 0.85 times or more, 0.86 times or more, 0.87 times or more, 0.88 times or more, or 0.89 times or more, and may be 1 times or less, 0.99 times or less, 0.98 times or less, 0.97 times or less, 0.96 times or less, 0.95 times or less, 0.94 times or less, 0.93 times or less, 0.92 times or less, 0.91 times or less, or 0.90 times or less. Preferably, it may be 0.80 times or more and 1 times or less, 0.80 times or more and 0.95 times or less, or 0.85 times or more and 0.95 times or less.

[0044] 150 N / cm in the thickness direction of the above aerogel composite 2 More than 300 N / cm 2 When the pressure below is applied, the thermal transmittance after compression is 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, or 1.3 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time.

[0045] 150 N / cm for the cross section of the above aerogel composite 2 When pressure is applied, the thermal transmittance after compression is 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, or 1.2 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time. Preferably, it may be more than 1 time and 1.7 times or less, more than 1 time and 1.5 times or less, or more than 1 time and 1.3 times or less.

[0046] 300 N / cm for the cross section of the above aerogel composite 2 When pressure is applied, the thermal transmittance after compression is 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, or 1.3 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time. Preferably, it may be more than 1 time and 2 times or less, more than 1 time and 1.7 times or less, or more than 1 time and 1.5 times or less.

[0047] 150 N / cm for the cross section of the above aerogel composite 2 and 300 N / cm 2When pressure is applied, the thermal transmittance after compression is 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, or 1.3 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time. Preferably, it may be more than 1 time and 2 times or less, more than 1 time and 1.7 times or less, or more than 1 time and 1.5 times or less.

[0048] Hereinafter, the present invention will be described in more detail to facilitate understanding. The terms and words used in this specification and claims should not be interpreted based on their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0049]

[0050] According to one embodiment of the present invention, there is provided an aerogel composite comprising a fiber substrate; and an aerogel including one or more pores.

[0051] The above "aerogel" includes a plurality of primary aerogel particles having a size of approximately 0 to 10 nm or more and 0 to 5 nm or less, and secondary aerogel particles formed by agglomeration or bonding of these primary aerogel particles, and a plurality of open pores are formed between the primary aerogel particles and between the secondary aerogel particles to form aggregates, thereby forming a three-dimensional network structure of the aerogel.

[0052] The aerogel may be an inorganic silica aerogel formed from a silicon alkoxide compound or water glass as a precursor. As an example, the aerogel may be composed of silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof. As another example, the aerogel may have at least a portion of the SiO2 on the surface and / or inside the pores of the SiO2 network having a bonding structure of Si-O-SiO2(CH3), Si-O-SiO(CH3)2, or Si-O-Si(CH3)3. A specific silica aerogel manufacturing process is described in detail below.

[0053] Aerogel particles may be positioned on the fiber substrate and in the gaps between adjacent fiber substrates. The "aerogel particles" are individual solid unit particles forming an aerogel, and may include both primary aerogel particles having a size of approximately 0 to 10 nm or more, or approximately 0 to 5 nm or less, preferably approximately 1 nm, and secondary aerogel particles formed by agglomeration of these particles. However, the aerogel in the aerogel composite is mostly secondary aerogel particles or a form in which these are agglomerated and combined, and a trace amount of primary aerogel particles that do not form secondary aerogel particles may be mixed in. The secondary aerogel particles may have an average particle diameter of, but is not limited to, approximately 5 to 2,000 nm, 5 to 1,000 nm, 5 to 500 nm, 5 to 100 nm, or 5 to 50 nm. The above average particle size may be measured by any means known to those skilled in the art, including, but not limited to, scanning electron microscopy, dynamic light scattering, optical microscopy, or size exclusion methods.

[0054] The aerogel may have a skeletal structure including mesopores, and may also include micropores or macropores in addition to the mesopores. Here, the "mesopores" are pores having an average pore diameter in a range of about 2 nm to about 50 nm, the "macropores" are pores having an average pore diameter in a range exceeding about 50 nm, and the "micropores" are pores having an average pore diameter in a range less than about 2 nm. The aerogel may include mesopores for at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% of the pore volume of the skeletal structure. In one specific example, the aerogel may include mesopores. In one specific example, the aerogel may include mesopores and micropores. The pore size may be measured by any means known to those skilled in the art, such as, but not limited to, gas adsorption experiments, mercury intrusion, capillary flow porometry, or positron annihilation lifetime spectroscopy (PALS).

[0055] The porosity of the above aerogel may be 80% or more, 85% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more, and preferably 80% or more and 99.9% or less, but is not limited thereto.

[0056] The above aerogel composite has a structure in which at least some of a plurality of aerogel particles are dispersed, preferably bonded, on the surface of a substrate including fibers, and at the same time, at least some of the plurality of aerogel particles are dispersed, preferably positioned, in the empty spaces between the fibers within the substrate. Examples of the substrate may include discrete fibers, films, sheets, nets, fibers, porous bodies, foams, non-woven fabrics, or laminates of two or more layers thereof. In addition, depending on the intended use, the surface may have surface roughness or may be patterned.

[0057] The above fiber substrate is selected from the group consisting of polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate (e.g., rayon, nylon), cotton (e.g., Lycra from DuPont), carbon (e.g., graphite), polyacrylonitrile (PAN), oxidized PAN, non-carbonized heat-treated PAN (e.g., from SGL Carbon), glass fiber-based materials (S-glass, 901 glass, 902 glass, 475 glass, E-glass, etc.), silica-based fibers such as quartz (e.g., Quartzel from Saint-Gobain), Q-felt (from Johns Manville), Saffil (from Saffil), Durablanket (from Unifrax) and other silica fibers, Duraback (from carborundum), polyaramid fibers such as Kevlar, Nomex, Sontera (all from DuPont), Conex (from Tyjin), polyolefins such as Tyvek (from DuPont), Dyneema (from DSM), Spectra (manufactured by Honeywell), other polypropylene fibers such as Typar, Xavan (both manufactured by DuPont), fluoropolymers such as PTFE under the Teflon brand name (manufactured by DuPont), Goretex (manufactured by WL GORE), silicon carbide fibers such as Nicalcon (manufactured by COI Ceramics), ceramic fibers such as Nextel (manufactured by 3M), ceramic paper, acrylic polymers, wool, silk, hemp, leather, suede fibers, PBO-Xylon fibers (manufactured by Teflon), liquid crystal materials such as Vectan (manufactured by Hoechst), Cambrel fibers (manufactured by DuPont), polyurethane, polyamide, wool fibers, basalt fibers, boron, aluminum, iron, stainless steel fibers, or other thermoplastic resins such as PEEK, PES, PET, PEK, PPS, but any fiber that can further improve the insulating performance by including spaces or voids into which the aerogel can be easily inserted may be used without limitation. As an example, the fiber substrate may include glass fibers.As another example, the fiber substrate may be, but is not limited to, made of glass fibers. As another example, the fiber substrate may be, but is not limited to, a glass fiber mat.

[0058] The thickness of the above fiber substrate may be, but is not limited to, 0.05 to 20 mm.

[0059] The above aerogel composite may have a rectangular shape and may have a fiber substrate and aerogel mixed from the top to the bottom, but is not limited thereto.

[0060] In addition, at least a portion of the upper or lower surface of the aerogel composite, preferably the entire surface, may have a flat shape. Here, the "flat shape" means that no irregularities are formed by intentional embossing or a coating process. In the present invention, forming the upper and lower surfaces of the aerogel composite flat as described above can increase the ease of work when laminating a support member such as a sheet on the surfaces of the upper and lower surfaces in the future, and can increase the adhesion maintenance rate of the support member. In addition, even if the aerogel composite itself is directly applied as an insulating member without a support member, it is preferable because the friction with the surface of an adjacent device can be reduced.

[0061] The thickness of the aerogel composite may be from 0.05 to 20 mm, for example, from 0.1 to 15 mm, from 0.1 to 10 mm, or from 0.1 to 5 mm, but is not limited thereto.

[0062] The density of the above aerogel composite is 0.05 to 0.50 g / cm 3 , 0.05 to 0.35 g / cm 3 , 0.05 to 0.30 g / cm 3 , 0.10 to 0.35 g / cm 3 , 0.10 to 0.30 g / cm 3 , 0.15 to 0.35 g / cm3 day or 0.15 to 0.30 g / cm 3 It may include, but is not limited to.

[0063] The insulating effect of an aerogel composite is achieved by blocking heat transferred due to the poor convection of air trapped within the pores or gaps between the discrete fibers contained in the aerogel. Therefore, in order to confirm the insulating properties of an aerogel composite after pressurization, it is desirable to check the change in the three-dimensional volume ratio of the gaps between the aerogel and the fibers, which contain pores that contribute to the insulating effect, in the aerogel composite before and after compression. Since the change in the thickness of the aerogel composite before and after compression also reflects the compressibility of the fibers, it is difficult to say that it accurately reflects the change in the insulating properties of the aerogel composite. In the present invention, 150 N / cm 2 After compressing the aerogel composite with the above pressure, the change in the volume ratio of the voids between the aerogel and the fibers containing pores was confirmed, and as a result of confirming the change in the thermal transmittance, the aerogel composite of the present invention has an excellent strength of the aerogel network structure including pores and pores, 150 N / cm 2 It was confirmed that even when compressed at high pressures, the volume change was small, and accordingly, there was no significant decrease in the level of insulation after compression.

[0064] Specifically, the volume ratio of the remaining portion excluding the fibers per unit volume of the aerogel composite, that is, the aerogel including pores, and the voids between the fibers may be comprised of 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, or 90% or more, and 98% or less, 97% or less, 96% or less, 95% or less, 94% or less, or 93% or less, and preferably 88 to 98%, or 90 to 95%. In the present specification, the voids refer to empty spaces between discrete fibers that are not filled with the aerogel.

[0065] The ratio of the volume of the fibers per unit volume of the aerogel composite may be comprised of 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, or 10% or more, and 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, or 10% or less, and preferably 2 to 12%, or 5 to 10%.

[0066] However, the unit volume of the aerogel composite here refers to the volume of the aerogel composite in the shape of a rectangular parallelepiped with a width X length of 1 cm X 1 cm. The unit volume of the aerogel composite refers to the volume of the aerogel composite in the shape of a rectangular parallelepiped with a width X length of 1 cm X 1 cm. At this time, the volume of the aerogel composite refers to the volume obtained by multiplying the width X length X thickness of the aerogel composite, assuming that any material is filled in the pores or voids between the discrete fibers in the aerogel up to the area not filled with the aerogel particles. The volume of the fibers per unit volume of the aerogel composite refers to the sum of the volumes occupied by the individual fibers included in the unit volume of the aerogel composite. The volume of the remaining area excluding the fibers per unit volume of the aerogel composite includes the volume of the voids between the aerogel including the pores and the discrete fibers. At this time, the volume of the pores and voids can be calculated assuming that any material is filled evenly in the pores and voids. In the present invention, the volume of the void between the aerogel and the fibers including pores per unit volume of the aerogel composite can be calculated by subtracting the volume of the fibers alone from the unit volume of the aerogel composite.

[0067] In addition, the aerogel composite may contain aerogel in an amount of 0.35 times or more, 0.4 times or more, or 0.45 times or more based on the weight of the fiber substrate, and for example, the fiber substrate and the aerogel may be contained in a weight ratio of 1:0.35 to 2, preferably 1:0.4 to 2, or 1:0.45 to 1.5.

[0068] 150 N / cm in the thickness direction for the above aerogel composite 2 When a pressure is applied, the volume ratio of the voids between the aerogel and the fibers including pores per unit volume of the aerogel composite may be 0.85 times or more, 0.86 times or more, 0.87 times or more, 0.88 times or more, 0.89 times or more, 0.90 times or more, 0.91 times or more, 0.92 times or more, 0.93 times or more, 0.94 times or more, or 0.95 times or more, and may be 1 time or less, 0.99 times or less, 0.98 times or less, 0.97 times or less, 0.96 times or less, 0.95 times or less, 0.94 times or less, 0.93 times or less, 0.92 times or less, 0.91 times or less, or 0.90 times or less. Preferably, it may be 0.85 times or more and 1 times or less, 0.85 times or more and 0.97 times or less, or 0.87 times or more and 0.97 times or less.

[0069] 300 N / cm in the thickness direction for the above aerogel composite 2When pressure is applied, the volume ratio of the voids between the aerogel and the fibers including the pores per unit volume of the aerogel composite may be 0.80 times or more, 0.81 times or more, 0.82 times or more, 0.83 times or more, 0.84 times or more, 0.85 times or more, 0.86 times or more, 0.87 times or more, 0.88 times or more, or 0.89 times or more, and may be 1 times or less, 0.99 times or less, 0.98 times or less, 0.97 times or less, 0.96 times or less, 0.95 times or less, 0.94 times or less, 0.93 times or less, 0.92 times or less, 0.91 times or less, or 0.90 times or less. Preferably, it may be 0.80 times or more and 1 times or less, 0.80 times or more and 0.95 times or less, or 0.85 times or more and 0.95 times or less.

[0070] 300 N / cm in the thickness direction for the above aerogel composite 2 When a pressure of 150 N / cm is applied, the volume ratio of the voids between the aerogel and the fibers containing pores per unit volume of the aerogel composite is 2 When a pressure of , the volume ratio of the aerogel including voids and pores per unit volume of the aerogel composite is 0.85 times or more, 0.86 times or more, 0.87 times or more, 0.88 times or more, 0.89 times or more, 0.90 times or more, 0.91 times or more, or 0.92 times or more, and may be 1 time or less, 0.99 times or less, 0.98 times or less, 0.97 times or less, 0.96 times or less, 0.95 times or less, 0.94 times or less, or 0.93 times or less. Preferably, it may be 0.89 times or more and 1 time or less, or 0.89 times or more and 0.99 times or less.

[0071] The volume ratio of the voids between the aerogel and the fibers including the pores per unit volume of the aerogel composite described above may be obtained by randomly obtaining a total of five rectangular parallelepiped specimens each having a width X length of 1 cm X 1 cm and a height equal to the thickness of the aerogel composite from the aerogel composite, and calculating the average value of the volume ratio of the aerogel including the pores and the pores per unit volume of the aerogel composite measured from each specimen. At this time, the five specimens may be obtained by ensuring that a position spaced 10 cm apart from each corner of an aerogel composite manufactured in a rectangular shape (for example, but not limited to, having a size of 60 cm X 12 cm) in the center direction is positioned at the exact center of the specimen, thereby obtaining four specimens, and ensuring that the exact center of the aerogel composite is also positioned at the exact center of the specimen, thereby obtaining one specimen.

[0072] In addition, the volume ratio of the voids between the aerogel and the fibers including pores per unit volume of the aerogel composite described above can be obtained by measuring the volume ratio of the fibers and the remaining portion excluding the fibers in the area to be analyzed (segmentation) using the VERSA 520 equipment of ZEISS and the Dragonfly software (version 2021.3). At this time, the size of the analysis area (width X length X height) is not particularly limited, and can be set and extracted below each size of the unit volume, and as an example, it can be set and extracted so that width X length X height is approximately 1700μm X 1600μm X 500μm. In order to measure the volume ratio of the voids between the aerogel and the fibers including pores per unit volume of the aerogel composite after compression, a load cell of DEBEN can be used to apply pressure to the aerogel composite specimen, and then the volume ratio can be measured using the same method. However, the above method is described for reference as an example of a method for measuring the volume ratio of the voids between the aerogel and the fibers including the pores per unit volume of the aerogel composite described herein, and is not limited to the above method.

[0073] The aerogel composite provided by the present invention exhibits minimal volume change in the aerogel and pores containing the pores even after pressurization. Consequently, its thermal conductivity does not change significantly, resulting in a low increase in thermal transmittance compared to before pressurization. Thus, the aerogel composite provided by the present invention maintains excellent thermal insulation performance without significant degradation due to pressurization.

[0074] Specifically, 150 N / cm in the thickness direction of the aerogel composite 2 More than 300 N / cm 2When the pressure below is applied, the thermal transmittance after compression is 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, or 1.3 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time.

[0075] In applying the above pressure, the “thickness direction” of the aerogel composite means the horizontal direction (transverse direction) with respect to the cross-section of the aerogel composite, and more specifically, may mean the direction from the upper surface to the lower surface of the aerogel composite or the direction from the lower surface to the upper surface.

[0076] The above "thermal transmittance" refers to the heat transfer from air layer to air layer through a solid object, and is 1 m in unit time. 2 It refers to the amount of heat that flows when there is a 1 ℃ temperature difference through the cross-sectional area of ​​a material, and it is the value obtained by dividing the thermal conductivity of a material by the thickness of the material. The amount of heat transfer of a material is affected by its thermal conductivity and the thickness of the material. The higher the thermal conductivity and the thinner the thickness, the greater the heat transfer. Therefore, in order to have excellent insulation performance, the thermal conductivity must be low and the thickness must be large. However, when pressure is applied to an elastic material such as an aerogel composite, the thermal conductivity and thickness may change after pressurization. In other words, unless it is a perfectly elastic material, the thickness will inevitably decrease after pressurization, but if the thermal conductivity does not change, the total heat transfer will increase due to the decrease in thickness. In other words, the insulation performance will inevitably decrease. Therefore, whether the insulation performance is maintained after pressurization cannot be confirmed simply by the thermal conductivity after pressurization, but can be confirmed through the thermal transmittance that considers both the thermal conductivity after pressurization and the thickness after pressurization. Even if the thermal conductivity decreases or is maintained after pressurization, if the thickness is greatly reduced after pressurization, the thermal transmittance and total heat transfer are bound to increase significantly.

[0077] The "pressure" value applied to measure the thermal transmittance after the above compression refers to the pressure value actually applied to the unit area of ​​the aerogel composite when applying pressure in the thickness direction of the aerogel composite using a press device, etc. As an example, when applying pressure in the horizontal direction (transverse direction) to the cross-section of the aerogel composite using a press device including a cylinder, the actual pressure value may refer to a value obtained by dividing the product of the cross-sectional area of ​​the cylinder and the set pressure value by the area of ​​the specimen, as shown in Equation 1 below, but is not limited thereto, and may be calculated differently depending on the specifications of each equipment or manufacturer.

[0078] [Formula 1]

[0079] Actual pressure value = (Inner cylinder radius of press equipment (cm) X Inner cylinder radius of press equipment (cm) X 3.14 X Set pressure value) / (Area of ​​specimen (cm) 2 ))

[0080] The above "post-compressed thermal transmittance" refers to the ratio of the thermal conductivity to the cross-sectional thickness of the aerogel composite after a predetermined period of time has elapsed after the aerogel composite has been compressed by applying a specific level of pressure in the thickness direction of the aerogel composite. Here, the predetermined period of time may be, for example, 1 second or more, 5 seconds or more, 10 seconds or more, 30 seconds or more, 1 minute or more, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, 2 hours or more, 4 hours or more, 6 hours or more, 8 hours or more, 10 hours or more, 12 hours or more, 24 hours or more, 48 hours or more, or 96 hours or more, but is not limited thereto. As an example, the post-compressed thermal transmittance may be measured 60 minutes (1 hour) after compressing the aerogel composite.

[0081] The time for applying pressure to the above aerogel composite is not particularly limited, but may be, for example, 1 second or more, 5 seconds or more, 10 seconds or more, 30 seconds or more, 1 minute or more, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 1 hour or more, or 2 hours or more, and 24 hours or less, 12 hours or less, 10 hours or less, 8 hours or less, 6 hours or less, 4 hours or less, 2 hours or less, 1 hour or less, 50 minutes or less, 40 minutes or less, 30 minutes or less, 20 minutes or less, 10 minutes or less, 5 minutes or less, 1 minute or less, 30 seconds or less, 10 seconds or less, or 5 seconds or less, but is not limited thereto. As an example, the time for applying pressure may be 10 minutes.

[0082] 150 N / cm for the cross section of the above aerogel composite 2 When pressure is applied, the thermal transmittance after compression is 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, or 1.2 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time. Preferably, it may be more than 1 time and 1.7 times or less, more than 1 time and 1.5 times or less, or more than 1 time and 1.3 times or less.

[0083] 300 N / cm for the cross section of the above aerogel composite 2 When pressure is applied, the thermal transmittance after compression is 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, or 1.3 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time. Preferably, it may be more than 1 time and 2 times or less, more than 1 time and 1.7 times or less, or more than 1 time and 1.5 times or less.

[0084] 150 N / cm for the cross section of the above aerogel composite 2 and 300 N / cm 2When pressure is applied, the thermal transmittance after compression is 2 times or less, 1.9 times or less, 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, or 1.3 times or less than the thermal transmittance before compression, and may additionally be 1 time or more or more than 1 time. Preferably, it may be more than 1 time and 2 times or less, more than 1 time and 1.7 times or less, or more than 1 time and 1.5 times or less.

[0085] The aerogel composite provided in the present invention can maintain its insulation performance at an excellent level without significant deterioration, as the thermal transmittance before and after compression is maintained within a specific range, regardless of the pressure applied (or compressed) at any intensity.

[0086] Specifically, for the aerogel composite, 0 to 300 N / cm 2 The heat transfer coefficient obtained after compression at least one of the pressure values ​​can satisfy the following equation 2:

[0087] [Formula 2]

[0088] {(Thermal transmittance before and after compression (a)) - (Average of thermal transmittances before and after compression (b))} = (Average of thermal transmittances before and after compression (b)) XA

[0089] In the above equation 2, the "thermal transmittance before and after compression (a)" is 0 to 300 N / cm in the horizontal direction (transverse direction) with respect to the cross-section of the aerogel composite. 2 It means the thermal transmittance obtained after compression at least one pressure value in the range, and for example, 0 N / cm for an aerogel composite. 2 , 150 N / cm 2 or 300 N / cm 2 It can mean the thermal transmittance obtained after compression by applying pressure of 0 N / cm. Here, the above 0 N / cm 2 The pressure of means unpressurized (uncompressed), and therefore 0 N / cm 2The thermal transmittance obtained after compression by applying pressure refers to the thermal transmittance of the unpressurized aerogel composite.

[0090] In addition, the above "average value (b) of thermal transmittances before and after compression" is the thermal transmittance of the aerogel composite without pressurization (or compression) and 0 N / cm in the horizontal direction (transverse direction) with respect to the cross-section of the aerogel composite. 2 Exceeding 300 N / cm 2 It means the average value of the thermal transmittances obtained after compression with at least two pressure values ​​in the range below. As an example, the thermal transmittance of an unpressurized (uncompressed) aerogel composite and the thermal transmittance of an aerogel composite at 150 N / cm 2 and 300 N / cm 2 It can mean the average value of the thermal transmittances obtained after compression by applying pressure at each pressure value.

[0091] The above A may be a real number of -0.30 to +0.30, a real number of -0.25 to +0.25, a real number of -0.24 to +0.24, a real number of -0.23 to +0.23, a real number of -0.22 to +0.22, a real number of -0.21 to +0.21, a real number of -0.20 to +0.20, a real number of -0.19 to +0.19, a real number of -0.15 to +0.15, a real number of -0.14 to +0.14, a real number of -0.13 to +0.13, or a real number of -0.12 to +0.12. Preferably, it may be a real number between -0.25 and +0.25, a real number between -0.23 and +0.23, a real number between -0.20 and +0.20, or a real number between -0.15 and +0.15.

[0092] As an example, uncompressed (0 N / cm) 2 The thermal transmittance of the aerogel composite can satisfy the above equation 2. At this time, the average value (b) of the thermal transmittances before and after compression is the thermal transmittance of the non-compressed aerogel composite and 150 N / cm in the thickness direction of the aerogel composite.2 and 300 N / cm 2 It can mean the average value of the heat transfer coefficients obtained after compression at each pressure value.

[0093] As an example, 150 N / cm for an aerogel composite 2 The thermal transmittance obtained after compression under pressure can satisfy the above equation 2. At this time, the average value (b) of the thermal transmittances before and after compression is 0 N / cm 2 Compression) Thermal transmittance of the aerogel composite and 150 N / cm in the thickness direction of the aerogel composite 2 and 300 N / cm 2 It can mean the average value of the heat transfer coefficients obtained after compression at each pressure value.

[0094] As an example, 300 N / cm for an aerogel composite 2 The thermal transmittance obtained after compression under pressure can satisfy the above equation 2. At this time, the average value (b) of the thermal transmittances before and after compression is 0 N / cm 2 Compression) Thermal transmittance of the aerogel composite and 150 N / cm in the thickness direction of the aerogel composite 2 and 300 N / cm 2 It can mean the average value of the heat transfer coefficients obtained after compression at each pressure value.

[0095] As an example, the average value (b) of the thermal transmittances before and after compression is 0 N / cm 2 Compression) Thermal transmittance of the aerogel composite and 150 N / cm in the thickness direction of the aerogel composite 2 and 300 N / cm 2 It can mean the average value of the thermal transmittances obtained after compression by applying each pressure.

[0096] As an example, in the above equation 2, A may be a real number from -0.30 to +0.30, a real number from -0.25 to +0.25, a real number from -0.23 to +0.23, or a real number from -0.20 to +0.20, but is not limited thereto.

[0097] In addition, for the above aerogel composite, 0 to 300 N / cm 2 The rate of change in the heat transfer coefficient (B) after compression per unit applied pressure obtained after compression at any two pressure values ​​among the pressures can satisfy the following equation 3:

[0098] [Formula 3]

[0099] B = │(Thermal transmittance after compression at pressure x - Thermal transmittance after compression at pressure y) / (x - y)│

[0100] In the above equation 3, x and y are each independently 0 to 300 N / cm 2 Any pressure value within the pressure range (unit: N / cm) 2 ), which are different pressure values,

[0101] The above B is greater than or equal to 0 and 2.0 X 10 -2 Below, 1.5 X 10 -2 Below, 1.4 X 10 -2 Below, 1.3 X 10 -2 Below, 1.2 X 10 -2 Below, 1.1 X 10 -2 Below, 1.0 X 10 -2 Below, 9.0 X 10 -3 Below, 8.0 X 10 -3 Below, 7.0 X 10 -3 Below, 6.0 X 10 -3 or less, or 5.0 X 10 -3 The following may be a mistake:

[0102] As an example, in the above equation 3, x and y are independently 0 and 150 N / cm, respectively. 2 , or 300 N / cm 2It can be any one of the pressure values.

[0103] As an example, in the above equation 3, x is 150 N / cm 2 , and y can be 0. In this case, B is greater than or equal to 0 and 2 X 10 -2 or less than or equal to 1.5 X 10 -2 Mistakes may include, but are not limited to, the following:

[0104] As an example, in the above equation 3, x is 300 N / cm 2 , and y can be 0. In this case, B is greater than or equal to 0 and 2 X 10 -2 Below, 1.5 X 10 -2 Less than or equal to 1.0 X 10 -2 Mistakes may include, but are not limited to, the following:

[0105] As an example, in the above equation 3, x is 300 N / cm 2 , and y is 150 N / cm 2 It can be. At this time, the above B is 0 or more and 1.0 X 10 -2 Below, or 9.0 X 10 -3 Mistakes may include, but are not limited to, the following:

[0106] When measuring the thermal transmittance after compression using a press device, etc. as described above, a single specimen can be prepared from the aerogel composite and measured. However, depending on the measurement device, if the width or length of the aerogel composite is smaller than the pressure-applying portion of the measurement device, the aerogel composite is cut into two or more pieces and rearranged so that both the width and length are larger than the pressure-applying device. Then, the compression recovery rate or thermal transmittance, etc. are measured. The measured values ​​are considered to be substantially the same as for a single specimen.

[0107] As an example, the post-compression recovery rate or post-compression thermal transmittance may be measured for a rectangular aerogel composite specimen having a width X length of 30 cm X 24 cm. In this case, if the width or length of the manufactured aerogel composite is less than 30 cm or 24 cm, respectively, two or more specimens may be arranged in parallel adjacent to each other so that the specimens have a size of 30 cm X 24 cm, and then measurements may be performed on these specimens.

[0108] The above aerogel composite may have excellent mechanical strength, with a compressive strength at 10% strain of 20 kPa to 80 kPA, 20 kPa to 70 kPA, 30 kPa to 80 KPa, 30 kPa to 70 kPA, 35 kPa to 80 kPA, or 35 kPa to 70 kPA. Here, the compressive strength may be measured by manufacturing a specimen according to the ASTM C165 standard.

[0109] The above aerogel composite has a tensile strength of 30 N / cm. 2 Up to 60 N / cm 2 , 40 N / cm 2 Up to 55 N / cm 2 , or 45 N / cm 2 Up to 55 N / cm 2 As such, it may have excellent flexibility. Here, the tensile strength may be measured by manufacturing a specimen according to the ASTM D638 standard.

[0110] The above aerogel composite can generally be formed by a step of preparing a silica sol; a gelation step after impregnating a fiber substrate with the silica sol; and a drying step. Each step is described below. However, the specific manufacturing process or examples described herein are not intended to be limited to any specific type of aerogel or its manufacturing method. The present disclosure may include any aerogel formed by any related manufacturing method known to those skilled in the art.

[0111] Manufacturing steps of silica sol

[0112] In the present invention, a silica sol can be prepared by mixing a silica precursor composition and a catalyst composition.

[0113] The above silica precursor composition may include water and / or a polar organic solvent in the silica precursor.

[0114] The above silica precursor can be any precursor that can be used to form a silica aerogel without limitation, and may be, for example, a silicon-containing alkoxide compound. Specifically, tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetra secondary butyl orthosilicate, tetra tertiary butyl orthosilicate, tetrahexyl orthosilicate, and tetracyclohexyl orthosilicate. It may be a tetraalkyl silicate such as tetracyclohexyl orthosilicate, tetradodecyl orthosilicate, etc. More specifically, among these, the silica precursor may be tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), or a mixture thereof.

[0115] Additionally, the silica precursor may be a water glass solution. Here, the water glass solution may refer to a diluted solution obtained by adding distilled water to water glass and mixing it, and the water glass may be sodium silicate (Na2SiO3), which is an alkaline silicic acid salt obtained by melting silicon dioxide (SiO2) and an alkali.

[0116] In addition, the silica precursor may include pre-hydrolyzed TEOS (HTEOS). HTEOS is an ethyl silicate oligomer material having a broad molecular weight distribution. Since the properties such as gelation time can be controlled when synthesizing it in the form of an oligomer from a TEOS monomer, it can be easily applied according to the user's reaction conditions. In addition, it has the advantage of producing reproducible properties of the final product. The HTEOS may be synthesized by a condensation reaction of TEOS that has undergone a partial hydration step under acidic conditions. That is, the HTEOS may be in the form of an oligomer manufactured by condensing TEOS, and the oligomer may be a partially hydrated form.

[0117] The above silica precursor composition can increase the pore strength of the aerogel composite by further including a silicate having a hydrophobic group to impart elasticity to the aerogel structure. The silicate having a hydrophobic group is not limited in type as long as it is an alkyl silane compound having an alkyl group that induces hydrophobicity and a silane functional group that can react with the -Si-O- functional group of the wet gel. For example, the silicate may be at least one selected from the group consisting of methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDEOS), ethyltriethoxysilane (ETES), and phenyltriethoxysilane (PTES), but is not limited thereto.

[0118] When the silica precursor composition includes a silicate containing the hydrophobic group, it may be included in a molar ratio of 2:98 to 98:2 with the tetraalkyl silicate (molar ratio of the hydrophobic group-containing silicate: tetraalkyl silicate). Within this range, the strength and insulating performance of the aerogel can be efficiently secured, while the structure does not collapse even when compressed at high pressure, thereby preventing a decrease in the insulating performance.

[0119] The silica concentration of the above silica precursor composition is 10 kg / m 3 Up to 100 kg / m 3 , 20 kg / m 3 Up to 80 kg / m 3 , 30 kg / m 3 Up to 70 kg / m 3 , 30 kg / m 3 Up to 60 kg / m 3 , or 35 kg / m 3 Up to 45 kg / m 3 However, the silica concentration may be, but is not limited to, the concentration of silica contained in the silica precursor composition, and may be appropriately adjusted by varying the contents of the silica precursor, organic solvent, and water.

[0120] The above silica precursor may be used in an amount such that the silica content contained in the silica sol is 0.1 wt% to 30 wt%, but is not limited thereto. When the silica content satisfies the above range, it is preferable in terms of securing excellent mechanical properties, particularly flexibility, of the aerogel composite while also having an improved insulating effect.

[0121] The polar organic solvent may include an alcohol, and specific examples thereof include monohydric alcohols such as methanol, ethanol, isopropanol, butanol, etc.; polyhydric alcohols such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and sorbitol, etc.; or combinations thereof; however, other solvents known to those skilled in the art may also be used without limitation. Among these, when considering miscibility with water and aerogel, the polar organic solvent may be a monohydric alcohol having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, butanol, for example, ethanol.

[0122] The above polar organic solvent can be used in an appropriate amount by a person skilled in the art, taking into account the degree of hydrophobicity in the final aerogel composite to be manufactured while promoting the surface modification reaction.

[0123] When preparing the above silica precursor composition, the silica precursor and the organic solvent may be mixed in a weight ratio of 1:0.1 to 5, or 1:0.5 to 3, but the present invention is not limited thereto. However, when the silica precursor composition includes a silicate having a hydrophobic group, a mixture of the silicate having a hydrophobic group and the tetraalkyl silicate and the organic solvent may be mixed in the weight ratio described above.

[0124] In addition, when preparing the silica precursor composition, the silica precursor and water may be mixed in a molar ratio of 1:0.5 to 10, 1:1 to 8, or 1:3 to 6, but the present invention is not limited thereto. However, when the silica precursor composition includes a silicate having a hydrophobic group, a mixture of the silicate having a hydrophobic group and tetraalkyl silicate and water may be mixed in the molar ratio.

[0125] The above silica precursor composition may further comprise an acid catalyst, and specifically, when an alkoxy silane compound other than a hydrolyzate is used as a precursor, an acid catalyst may be further comprised. At this time, the acid catalyst may be used without limitation as long as it makes the pH 3 or lower, and examples thereof include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, or acetic acid. At this time, the acid catalyst may be added in an amount such that the pH of the sol becomes 3 or lower, and may be added in the form of an aqueous solution dissolved in an aqueous solvent.

[0126] The above catalyst composition may include an inorganic base such as sodium hydroxide or potassium hydroxide as a base catalyst; or an organic base such as ammonium hydroxide. Specific examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), ammonia (NH3), ammonium hydroxide (NH4OH; ammonia water), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), methylamine, ethylamine, isopropylamine, monoisopropylamine, diethylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, choline, monoethanolamine, diethanolamine, 2-aminoethanol, 2-(ethyl amino)ethanol, 2-(methyl amino)ethanol, N-methyl diethanolamine, dimethylaminoethanol, diethylaminoethanol, nitrilotriethanol, It may be, but is not limited to, 2-(2-aminoethoxy)ethanol, 1-amino-2-propanol, triethanolamine, monopropanolamine, dibutanolamine, pyridine, or a combination thereof.

[0127] The above base catalyst may be included in an amount such that the pH of the sol is 5 to 9. If the pH of the sol is outside the above range, gelation may not be easy or the gelation speed may be excessively slow, which may lower the processability. In addition, since the base may precipitate when introduced in a solid state, it may be preferable to add it in the form of a solution diluted with an aqueous solvent or the above organic solvent. In this case, the dilution ratio of the base catalyst and the organic solvent, specifically, alcohol, may be 1:4 to 1:100 by volume, but is not limited thereto.

[0128] In order to prepare the silica sol, the silica precursor composition and the catalyst composition may be mixed in a volume ratio of 1:0.01 to 10.0, 1:0.01 to 5.0, or 1:0.01 to 2.0, but is not limited thereto.

[0129] In the present invention, additives may be added to the silica sol as needed. Any known additives that can be added during the manufacture of aerogels may be used. For example, additives such as opacifiers and flame retardants may be used.

[0130] The above additive may be added in an amount of 0.1 wt% to 10 wt%, 0.1 wt% to 7 wt%, 0.5 wt% to 7 wt%, or 0.5 wt% to 5 wt% relative to the silica content of the aerogel, but is not limited thereto.

[0131] Gelation stage of silica sol

[0132] In the present invention, the silica sol can be impregnated into the substrate and then the silica sol can be gelated.

[0133] The above impregnation process is a process for allowing the catalyzed silica sol to penetrate the internal pores of the substrate, and can be performed by placing the catalyzed silica sol and the substrate into a reaction vessel, or by spraying the catalyzed silica sol onto the substrate moving on a conveyor belt according to a roll-to-roll process. At this time, the substrate can be lightly pressed to ensure sufficient impregnation to improve the bonding between the substrate and the silica sol. Afterwards, the material can be pressed to a certain thickness at a certain pressure to remove excess silica sol, thereby reducing the drying time.

[0134] The temperature of the silica sol in the reaction vessel may be 1 to 40° C., 20 to 40° C., 25 to 40° C., 30 to 40° C., or 35 to 45° C. When the temperature of the silica sol in the reaction vessel satisfies the above range, the aforementioned viscosity range of the catalyzed sol can be more easily achieved, and the desired viscosity range can be satisfied even with a relatively short residence time, which is preferable.

[0135] The above catalyzed silica sol can be impregnated into the substrate at a volume ratio of 0.1 to 10:1 (catalyzed silica sol:substrate), 0.1 to 1:1, 0.3 to 1:1, 0.5 to 1:1, or 0.6 to 1:1, but is not limited thereto.

[0136] When preparing the silica sol, the ratio of the silica precursor composition, the organic solvent, and the water can be adjusted, and the volume ratio between the silica sol and the substrate can be adjusted in the impregnation step, thereby controlling the density ratio of the fiber substrate and the aerogel within the aerogel composite. It is preferable that the density ratio of the fiber substrate and the aerogel be 1:0.6 to 1, as this can increase the strength of the aerogel composite.

[0137] The silica sol impregnated into the substrate can be gelled simultaneously with the impregnation process of the above silica sol or sequentially after the impregnation process.

[0138] In the present invention, a substrate impregnated with a catalyzed sol can be gelled on a moving element such as a conveyor belt.

[0139] The above "gelation" may refer to a sol-gel reaction, and the above "sol-gel reaction" may be a network structure formed from a silicon unit precursor material. Here, the network structure may refer to a planar net-shaped structure in which a specific polygon having one or more types of atomic arrangements is connected, or a structure in which a three-dimensional skeletal structure is formed by sharing vertices, edges, faces, etc. of a specific polyhedron.

[0140] The above gelation can be performed under an ambient temperature of 20 to 40°C, 20 to 30°C, 25 to 40°C, 30 to 40°C or 35 to 40°C, and is particularly preferably performed under an ambient temperature of 30 to 40°C or 35 to 40°C, but is not limited thereto, as this can increase the strength of the pores in the aerogel composite.

[0141] The above gelation may be performed for 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 may be appropriately adjusted by considering the gelation temperature, the amount of silica sol, etc.

[0142] Maturation stage of the gelled wet gel complex

[0143] The present invention may further include, if necessary, a maturation step in which the wet gel composite obtained through gelation as described above is left at an appropriate temperature to ensure complete chemical change. The maturation step further strengthens the network structure formed through gelation, thereby enhancing the mechanical stability of the aerogel composite.

[0144] The above maturation step can be performed by leaving the gelled wet gel complex at an appropriate temperature as is or by adding a cross-linking promoting compound.

[0145] In the above-mentioned maturation step, in the presence of the above-mentioned 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 at a concentration of 1 to 10% may be added. In this case, there is an effect of maximally inducing Si-O-Si bonds within the aerogel, thereby making the network structure of the silica gel more solid, thereby facilitating the maintenance of the pore structure in the subsequent drying process. At this time, the organic solvent may be the aforementioned alcohol, and specifically, may include ethanol.

[0146] In addition, by adding a mixed solution of an alkoxy silane compound and an alcohol during the maturation step, not only unreacted sol but also an additional sol precursor source is provided, thereby inducing additional gelation in the silica gel network structure, thereby further strengthening the gel structure. At this time, the alkoxy silane compound may be included in an amount of 0.5 parts by weight to 9.5 parts by weight, 1.0 parts by weight to 9.5 parts by weight, or 1.5 parts by weight to 9.5 parts by weight relative to 100 parts by weight of the total maturation solution.

[0147] The above alkoxy silane compounds include tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetra secondary butyl orthosilicate, tetra tertiary butyl orthosilicate, tetrahexyl orthosilicate, and tetracyclohexyl. It may include at least one 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.

[0148] In addition, the alcohol may be a monohydric alcohol such as methanol, ethanol, isopropanol, butanol, etc.; or a polyhydric alcohol such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and sorbitol, etc.; preferably, a monohydric alcohol having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, butanol, etc., such as ethanol, but is not limited thereto.

[0149] The above maturation step can be performed at a temperature of 30°C to 80°C, 40°C to 80°C, or 50°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours to strengthen the pore structure, and within this range, a decrease in productivity can be prevented while preventing loss of solvent due to evaporation, thereby preventing an increase in production cost.

[0150] In addition, the above aging step may be performed first by leaving the mixture at 30°C to 80°C for 0.1 to 5 hours to strengthen the pore structure, and then a solution of the above-mentioned base catalyst diluted in an organic solvent or a mixed solution of an alkoxy silane compound and alcohol may be added to perform second aging at 30°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours.

[0151] The above maturation step may be performed in a separate reaction vessel after recovering the gelled wet gel composite, or may be performed inside the reaction vessel in which the gelling step was performed.

[0152] Surface modification step of the matured wet gel composite

[0153] In the present invention, if necessary, a surface modification step may be further included to hydrophobize the surface of the wet gel composite obtained by gelation as described above or the matured wet gel composite in the presence of a surface modifier.

[0154] The above surface modifier may be applied without limitation to any compound that hydrophobicizes the wet gel surface, and may be, for example, a silane-based compound, a siloxane-based compound, a silanol-based compound, a silazane-based compound, or a combination thereof. Specific examples include silane compounds including trimethylchlorosilane (TMCS), dimethyldimethoxysilane, dimethyl diethoxysilane, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), vinyltrimethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, dimethyldichlorosilane, 3-aminopropyltriethoxysilane, etc.; siloxane compounds including polydimethyl siloxane, polydiethyl siloxane, or octamethyl cyclotetrasiloxane, etc.; Silanol compounds including trimethylsilanol, triethylsilanol, triphenylsilanol, and t-butyldimethylsilanol; Silazane compounds including 1,2-diethyldisilazane, 1,1,2,2-tetramethyldisilazane, 1,1,3,3-tetramethyl disilazane, 1,1,1,2,2,2-hexamethyldisilazane (HMDS), 1,1,2,2-tetraethyldisilazane, or 1,2-diisopropyldisilazane; or a combination thereof, but is not limited thereto.

[0155] The above surface modifier may be used in the form of a solution diluted in an organic solvent. Here, the organic solvent may be alcohol (organic solvent), and the surface modifier may be diluted to 1 to 15% by volume based on the total volume of the diluted solution.

[0156] In addition, the surface modifier may be added in an amount of 0.01 to 90 volume% to the wet gel composite to achieve a sufficient surface modification effect, but is not limited thereto.

[0157] The above surface modification step may be performed at a temperature of 50 to 90°C or 50 to 80°C for 1 to 24 hours, but is not limited thereto.

[0158] Drying stage

[0159] The present invention may include a drying step of drying the surface-modified wet gel composite to obtain an aerogel composite.

[0160] The above drying is performed by a process of removing only the solvent while maintaining the pore structure of the matured gel, and can be performed by, for example, supercritical drying or atmospheric pressure drying.

[0161] The above supercritical drying process is performed using supercritical carbon dioxide. For example, a matured wet gel composite is placed in a supercritical drying reactor, then liquid CO2 is filled, and a solvent substitution process is performed to replace the alcohol solvent inside the wet gel with CO2. Then, the temperature is increased to a temperature of 40 to 70°C at a constant temperature increase rate, for example, 0.1 to 1°C / min, and then a pressure higher than the pressure at which carbon dioxide becomes supercritical, for example, a pressure of 100 to 150 bar, is maintained so that the carbon dioxide can be maintained in the supercritical state for a certain period of time, specifically, 20 minutes to 1 hour. Generally, carbon dioxide becomes supercritical at a temperature of 31°C and a pressure of 73.8 bar. An aerogel composite can be manufactured by maintaining the carbon dioxide at a certain temperature and pressure at which it becomes supercritical for 2 to 12 hours, more specifically, 2 to 6 hours, and then gradually removing the pressure to complete the supercritical drying process, but is not limited thereto.

[0162] In addition, the above atmospheric pressure drying process can be performed according to a conventional method such as hot air drying or IR drying at a temperature of 70 to 200°C and atmospheric pressure (1±0.3 atm), but is not limited thereto.

[0163] In addition to the aforementioned process, the present invention also includes acidification of a basic metal oxide precursor (e.g., sodium silicate) in water to prepare a hydrogel. Salt byproducts can be removed from the silicate precursor by ion exchange and / or by subsequent washing of the formed gel with water. Removal of water from the pores of the gel can be accomplished by exchange with a polar organic solvent, such as ethanol, methanol, or acetone. The liquid phase within the gel is then at least partially extracted using innovative processing and extraction techniques.

[0164] In addition to the above-described process, the present invention includes reducing damaging capillary forces at the solvent / pore interface by chemically modifying the matrix material in a wet gel state through conversion of surface hydroxyl groups into hydrophobic trimethylsilyl ether, thereby enabling liquid phase extraction from the gel material at a temperature and pressure below the critical point of the solvent.

[0165] In addition to the aforementioned process, the present invention allows the liquid (solvent) within the gel material to be frozen at a lower temperature, followed by a sublimation process to remove the solvent from the gel material. Such removal or drying of the solvent from the gel material is understood to be within the scope of the present disclosure. Such removal largely preserves the gel structure, resulting in an aerogel with unique properties.

[0166] The aerogel composite provided by the present invention can be usefully used as an insulating material, heat-insulating material, or fire-retardant material for various industrial facilities, such as pipes or industrial furnaces, as well as for heat-insulating plant facilities, such as aircraft, ships, automobiles, electronic devices, and batteries.

[0167]

[0168] According to another embodiment of the present invention, there is provided an insulating member comprising an aerogel composite provided by the present invention.

[0169] The above insulating member may include the above-described aerogel composite and a support member positioned on at least one of the upper and lower surfaces of the aerogel composite.

[0170] Examples of the above-mentioned support member include a film-like support member, a sheet-like support member, a thin support member, a porous support member, and the like.

[0171] The above film-shaped support member is formed into a thin film from a polymer raw material, and examples thereof include organic films such as PET and polyimide, glass films, etc. (including metal deposition films).

[0172] The above sheet-like support member is formed from a fiber-like raw material of organic, inorganic or metallic origin, and may include paper, non-woven fabric (including glass mat), organic fiber fabric, glass cloth, etc.

[0173] The above-mentioned thin support member is formed by forming a metal raw material into a thin film, and examples thereof include aluminum foil, copper foil, etc.

[0174] The above porous support member has a porous structure made of organic, inorganic or metal raw materials, and examples thereof include porous organic materials (e.g., polyurethane foam), porous inorganic materials (e.g., zeolite sheets), and porous metal materials (e.g., porous metal sheets, porous aluminum sheets).

[0175] 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.

[0176] The above insulating material can also be applied as an insulating material, heat-insulating material, or fire-retardant material in the fields of construction, aviation, automobiles, batteries, home appliances, semiconductors, and industrial equipment.

[0177]

[0178] Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples.

[0179] Example

[0180]

[0181] [Example 1] Preparation of an aerogel composite

[0182] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethylorthosilicate (TEOS) in a molar ratio of 1:9. The silica precursor composition and ethanol were mixed in a weight ratio of 1:1.8, and the silica precursor composition and water in a molar ratio of 1:5 were added to prepare a silica sol. To promote hydrolysis, hydrochloric acid was added so that the pH of the silica sol became 3 or lower, and the mixture was stirred for more than 6 hours. A catalyzed sol was prepared by adding the silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling an impregnation tank with this catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol in a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel was 1:0.8. The fiber, which had passed through the impregnation tank and was permeated with the catalyzed sol, passed on a conveyor belt at a constant speed and was gelled. At this time, the ambient temperature on the conveyor belt was maintained at 35 ℃. After gelation was completed, it was stabilized at room temperature (25 ℃) for 10 minutes, and then primary maturation was performed for 30 minutes in a 70 ℃ oven. Afterwards, a 3.4 wt% tetraethylorthosilicate (TEOS) solution (solvent: ethanol) was prepared and added to the gelated wet gel composite in an amount of 109% based on the volume of the wet gel composite, and secondary maturation was performed in a 75 ℃ oven for 1 hour. A solution (10 vol.%) of trimethylethoxysilane (TMES) diluted in ethanol as a surface modifier was added to the wet gel composite in an amount of 90 vol.% based on the volume of the wet gel composite, and then 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. Afterwards, the temperature inside the extractor was increased to 70°C over 1 hour and 20 minutes, and when it reached 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the CO2 injection was stopped for 20 minutes. This process was repeated 4 times.Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. CO2 was then vented over a period of 2 hours to produce a hydrophobic silica aerogel composite with a density of approximately 0.219 g / cc.

[0183]

[0184] [Example 2] Preparation of an aerogel composite

[0185] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethylorthosilicate (TEOS) in a molar ratio of 1:9. The silica precursor composition and ethanol were mixed in a weight ratio of 1:1.3, and the silica precursor composition and water in a molar ratio of 1:4 were added to prepare a silica sol. To promote hydrolysis, hydrochloric acid was added so that the pH of the silica sol became 3 or lower, and the mixture was stirred for more than 6 hours. A catalyzed sol was prepared by adding the silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling an impregnation tank with this catalyzed sol, a fiber (glass fiber mat, 3 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol in a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel became 1:1. The fiber, which had passed through the impregnation tank and was permeated with the catalyzed sol, passed on a conveyor belt at a constant speed and was gelled. At this time, the ambient temperature on the conveyor belt was maintained at 40℃. After gelation was completed, it was stabilized at room temperature (25℃) for 10 minutes, and then primary maturation was performed for 30 minutes in a 70℃ oven. Afterwards, a solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the gelated wet gel composite in an amount of 109% based on the volume of the wet gel composite, and secondary maturation was performed in a 75℃ oven for 2 hours. A solution (10 vol.%) of trimethylethoxysilane (TMES) diluted in ethanol as a surface modifier was added to the wet gel composite in an amount of 90 vol.% based on the volume of the wet gel composite, and then 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. Afterwards, the temperature inside the extractor was increased to 70°C over 1 hour and 20 minutes, and when it reached 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the CO2 injection was stopped for 20 minutes. This process was repeated 4 times.Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. CO2 was then vented over a period of 2 hours to produce a hydrophobic silica aerogel composite with a density of approximately 0.242 g / cc.

[0186]

[0187] [Example 3] Preparation of an aerogel composite

[0188] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethylorthosilicate (TEOS) in a molar ratio of 1:9. The silica precursor composition and ethanol were mixed in a weight ratio of 1:2.8, and the silica precursor composition and water in a molar ratio of 1:5 were added to prepare a silica sol. To promote hydrolysis, hydrochloric acid was added so that the pH of the silica sol became 3 or lower, and the mixture was stirred for more than 6 hours. A catalyzed sol was prepared by adding the silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling an impregnation tank with this catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol in a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel became 1:0.6. The fiber, which had passed through the impregnation tank and was permeated with the catalyzed sol, passed on a conveyor belt at a constant speed and was gelled. At this time, the ambient temperature on the conveyor belt was maintained at 40℃. After gelation was completed, it was stabilized at room temperature (25℃) for 10 minutes, and then primary maturation was performed for 30 minutes in a 70℃ oven. Afterwards, a solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the gelated wet gel composite in an amount of 109% based on the volume of the wet gel composite, and secondary maturation was performed in a 75℃ oven for 1 hour. A solution (10 vol.%) of trimethylethoxysilane (TMES) diluted in ethanol as a surface modifier was added to the wet gel composite in an amount of 90 vol.% based on the volume of the wet gel composite, and then 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. Afterwards, the temperature inside the extractor was increased to 70°C over 1 hour and 20 minutes, and when it reached 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the CO2 injection was stopped for 20 minutes. This process was repeated 4 times.Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. CO2 was then vented over a period of 2 hours to produce a hydrophobic silica aerogel composite with a density of approximately 0.192 g / cc.

[0189]

[0190] [Example 4] Preparation of an aerogel composite

[0191] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethylorthosilicate (TEOS) in a molar ratio of 1:9. The silica precursor composition and ethanol were mixed in a weight ratio of 1:1.3, and the silica precursor composition and water in a molar ratio of 1:4 were added to prepare a silica sol. To promote hydrolysis, hydrochloric acid was added so that the pH of the silica sol became 3 or lower, and the mixture was stirred for more than 6 hours. A catalyzed sol was prepared by adding the silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling an impregnation tank with this catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol in a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel became 1:1. The fiber, which had passed through the impregnation tank and was permeated with the catalyzed sol, passed on a conveyor belt at a constant speed and was gelled. At this time, the ambient temperature on the conveyor belt was maintained at 40℃. After gelation was completed, it was stabilized at room temperature (25℃) for 10 minutes, and then primary maturation was performed for 30 minutes in a 70℃ oven. Afterwards, a mixture of ethanol and ammonia water (volume ratio of 98:2) was prepared and added to the gelated wet gel composite in an amount 1.6 times the volume of the silica sol, and secondary maturation was performed for 5 hours in a 70℃ oven. A solution (10 volume%) of trimethylethoxysilane (TMES) diluted in ethanol as a surface modifier was added to the wet gel composite in an amount of 90 volume% based on the volume of the wet gel composite, and then 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. Afterwards, the temperature inside the extractor was increased to 70°C over 1 hour and 20 minutes, and when it reached 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the CO2 injection was stopped for 20 minutes. This process was repeated 4 times.Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. CO2 was then vented over a period of 2 hours to produce a hydrophobic silica aerogel composite with a density of approximately 0.241 g / cc.

[0192]

[0193] [Example 5] Preparation of an aerogel composite

[0194] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethylorthosilicate (TEOS) in a molar ratio of 1:9. The silica precursor composition and ethanol were mixed in a weight ratio of 1:1.3, and the silica precursor composition and water in a molar ratio of 1:4 were added to prepare a silica sol. To promote hydrolysis, hydrochloric acid was added so that the pH of the silica sol became 3 or lower, and the mixture was stirred for more than 6 hours. A catalyzed sol was prepared by adding the silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling an impregnation tank with this catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol in a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel became 1:1. The fiber, which had passed through the impregnation tank and was permeated with the catalyzed sol, passed on a conveyor belt at a constant speed and was gelled. At this time, the ambient temperature above the conveyor belt was maintained at 35℃. After gelation, it was stabilized at room temperature (25 ℃) for 10 minutes, and then primary maturation was performed in a 70 ℃ oven for 30 minutes. Afterwards, a mixture of ethanol and ammonia water (volume ratio of 98:2) was prepared and added to the gelled wet gel composite in an amount 1.6 times the volume of silica sol, and secondary maturation was performed in a 70 ℃ oven for 3 hours. As a surface modifier, a solution (10 vol%) of trimethylethoxysilane (TMES) diluted in ethanol was added to the wet gel composite in an amount of 90 vol% based on the volume of the wet gel composite, and then 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. Afterwards, the temperature in the extractor was raised to 70 ℃ over 1 hour and 20 minutes, and when it reached 70 ℃ and 150 bar, 20 The process of injecting and discharging CO2 at a rate of 0.5 L / min and maintaining the CO2 injection stopped for 20 minutes was repeated 4 times.Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. CO2 was then vented over a period of 2 hours to produce a hydrophobic silica aerogel composite with a density of approximately 0.238 g / cc.

[0195]

[0196] [Comparative Example 1] Preparation of an aerogel composite

[0197] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and ethanol at a weight ratio of 1:0.5 and adding water at a molar ratio of TEOS to 1:4. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol at a weight ratio of 1:0.8 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) at a volume ratio of 99:1 to the silica sol. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol at a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel was 1:0.8. The fibers, which had been impregnated with the catalyzed sol after passing through the impregnation tank, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 25℃. To the manufactured wet gel composite, a solution of 2.4 wt% ammonium hydroxide (NH4OH) diluted in ethanol with a moisture content of 10 wt% was added as a maturing solution in an amount of 109% based on the volume of the wet gel composite, and maturing was performed at a temperature of 75℃ for 1 hour. To the aged wet gel composite, a solution of hexamethyldisilazane (HMDS) / ethanol (5:95 volume ratio) was added as a surface modifier in an amount of 90% by volume based on the volume of the wet gel composite, and then surface modification was performed at a temperature of 75℃ for 4 hours. The silica wet gel was placed in a 7.2 L supercritical extractor and CO2 was injected. Afterwards, the temperature inside the extractor was increased to 70 ℃ over 1 hour and 20 minutes, and when it reached 70 ℃ and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the CO2 injection was stopped for 20 minutes. This process was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge.CO2 was vented over the next two hours to produce a hydrophobic silica aerogel composite having a density of approximately 0.210 g / cc.

[0198]

[0199] [Comparative Example 2] Manufacturing of an Aerogel Composite

[0200] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and ethanol at a weight ratio of 1:0.5 and adding water at a molar ratio of TEOS to 1:4. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol at a weight ratio of 1:1.4 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) at a volume ratio of 99:1 to the silica sol. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol at a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel was 1:0.6. The fibers, which had been impregnated with the catalyzed sol after passing through the impregnation tank, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 25℃. A 1.7 wt% tetraethylorthosilicate (TEOS) solution (solvent: ethanol) was prepared as a maturing solution for the manufactured wet gel composite, and 109% of the wet gel composite volume was added, and maturing was performed in an oven at 75℃ for 1 hour. A hexamethyldisilazane (HMDS) / ethanol solution (5:95 volume ratio) was added as a surface modifier to the aged wet gel composite, and 90% of the wet gel composite volume was added, and surface modification was performed at 75℃ for 4 hours. The silica wet gel was placed in a 7.2 L supercritical extractor and CO2 was injected. Afterwards, the temperature inside the extractor was increased to 70 ℃ over 1 hour and 20 minutes, and when it reached 70 ℃ and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the CO2 injection was stopped for 20 minutes. This process was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge.CO2 was vented over the next two hours to produce a hydrophobic silica aerogel composite having a density of approximately 0.192 g / cc.

[0201]

[0202] [Comparative Example 3] Manufacturing of an aerogel composite

[0203] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethylorthosilicate (TEOS) in a molar ratio of 1:9. The silica precursor composition and ethanol were mixed in a weight ratio of 1:3.5, and the silica precursor composition and water in a molar ratio of 1:5 were added to prepare a silica sol. To promote hydrolysis, hydrochloric acid was added so that the pH of the silica sol became 3 or lower, and the mixture was stirred for more than 6 hours. A catalyzed sol was prepared by adding the silica sol and a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1. After filling an impregnation tank with this catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol in a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel became 1:0.5. The fiber, which had passed through the impregnation tank and was permeated with the catalyzed sol, passed on a conveyor belt at a constant speed and was gelled. At this time, the ambient temperature on the conveyor belt was maintained at 25℃. The manufactured silica wet gel composite was aged in an ethanol solution at a temperature of 70℃ for 1 hour. After the aged wet gel composite was added with 90% by volume of hexamethyldisilazane (HMDS) / ethanol solution (volume ratio of 5:95) as a surface modifier based on the volume of the wet gel composite, the surface was modified at a temperature of 75℃ for 4 hours. The silica wet gel was placed in a 7.2 L supercritical extractor and CO2 was injected. Thereafter, the temperature inside the extractor was raised to 70℃ over 1 hour and 20 minutes, and when 70℃ 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 the CO2 injection for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. CO2 was then vented over a period of 2 hours to produce a hydrophobic silica aerogel composite with a density of approximately 0.180 g / cc.

[0204]

[0205] [Comparative Example 4] Manufacturing of an Aerogel Composite

[0206] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and ethanol at a weight ratio of 1:0.5 and adding water at a molar ratio of TEOS to 1:4. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol at a weight ratio of 1:0.45 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) at a volume ratio of 99:1 to the silica sol. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein, and the fiber was impregnated with the catalyzed sol at a volume ratio of 1:1 so that the weight ratio of the fiber to the aerogel was 1:1. The fibers, which had been impregnated with the catalyzed sol after passing through the impregnation tank, were gelled while passing at a constant speed on the conveyor belt. At this time, the ambient temperature on the conveyor belt was maintained at 25℃. A solution (10% by volume) of trimethylethoxysilane (TMES) diluted in ethanol as a surface modifier was added to the manufactured wet gel composite at 90% by volume based on the volume of the wet gel composite, and the 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. The temperature inside the extractor was then raised to 70℃ over 1 hour and 20 minutes, and when it reached 70℃ and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the CO2 injection was stopped for 20 minutes. This process was repeated 4 times. Ethanol was recovered through the bottom of the separator during the CO2 injection and discharge. CO2 was vented over the next two hours to produce a hydrophobic silica aerogel composite having a density of approximately 0.244 g / cc.

[0207]

[0208] [Comparative Example 5] Manufacturing of an aerogel composite

[0209] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and ethanol at a weight ratio of 1:0.5 and adding water at a molar ratio of TEOS to 1:4. To promote hydrolysis of the silica precursor solution, acid was added so that the pH of the silica precursor solution became 3 or lower, and the mixture was stirred for more than 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol at a weight ratio of 1:2.4 to the hydrated TEOS solution. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) at a volume ratio of 99:1 to the silica sol. After filling the impregnation tank with the catalyzed sol, a fiber (glass fiber mat, 5 mm) as a substrate was impregnated therein so that the fiber was impregnated with the catalyzed sol at a volume ratio of 1:1, so that the weight ratio of the fiber to the aerogel was 1:0.4. The fibers, which had passed through the impregnation tank and were infiltrated with the catalyzed sol, were gelled as they passed along the conveyor belt at a constant speed. At this time, the ambient temperature on the conveyor belt was maintained at 35℃. After gelation was completed, they were stabilized at room temperature (25℃) for 10 minutes, and then subjected to primary maturation in a 70℃ oven for 30 minutes. Afterwards, a mixture of ethanol and ammonia water (volume ratio of 98:2) was prepared and added to the gelled wet gel composite in an amount 1.6 times the volume of the silica sol, followed by secondary maturation in a 70℃ oven for 1 hour. A hexamethyldisilazane (HMDS) / ethanol solution (volume ratio of 5:95) as a surface modifier was added to the aged wet gel composite in an amount of 90 vol% based on the volume of the wet gel composite, and then surface modification was performed at a temperature of 75℃ for 4 hours. Silica wet gel was placed in a 7.2 L supercritical extractor and CO2 was injected. The temperature inside the extractor was then raised to 70°C over 1 hour and 20 minutes, and 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 CO2 injection was stopped for 20 minutes. This process was repeated 4 times.Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. CO2 was then vented over a period of 2 hours to produce a hydrophobic silica aerogel composite with a density of approximately 0.168 g / cc.

[0210]

[0211] [Experimental Example 1] Analysis of the volume fraction of aerogels containing voids and pores in an aerogel composite

[0212] In order to analyze the volume ratio of only the fibers and the volume ratio of the aerogel including the gaps between the fibers and the multiple pores in the remaining portion excluding the fibers in the aerogel composites obtained in Examples 1 to 5 and Comparative Examples 1 to 5, first, the aerogel composites of Examples 1 to 5 and Comparative Examples 1 to 5, which were manufactured to have a width X length of approximately 60 cm X 12 cm and a height of approximately 0.4 cm, were prepared, and then five rectangular parallelepiped specimens each having a width X length of 1 cm X 1 cm were obtained therefrom. However, at this time, four specimens were obtained by ensuring that the positions spaced 10 cm apart from each edge of the aerogel composite in the center direction were located at the exact center of the specimen, and one specimen was obtained by ensuring that the exact center of the aerogel composite was also located at the exact center of the specimen.

[0213] After placing the specimen on the DEBEN load cell, the load cell was assembled, and the stage of the equipment was changed to a dedicated stage that can fix the load cell. First, in-situ XRM analysis was performed using the VERSA 520 equipment of ZEISS under the conditions shown in Table 1 below without applying pressure. After the analysis was completed, DEBEN's microtest software was activated and a constant load of 150 N / cm was applied to the aerogel composite to confirm the change in the volume ratio of the aerogel containing voids and multiple pores.2 or 300 N / cm 2 In-situ XRM analysis was performed by setting .

[0214] Acceleration voltage 80 kV Voxel size 2.5 μm Objective lens magnification 4X Exposure time 1 s / frame Total number of frames 3201

[0215] Based on the analysis results above, Dragonfly software (version 2021.3) was used to confirm the volume ratio of aerogel, including fibers, pores, and air voids, in the aerogel composite specimens before and after compression. To help understand the analysis method, an example analysis process is described below with reference to Figures 1 to 3. After the in-situ XRM analysis was completed, the results were activated with Dragonfly software, and the segmentation area was set and extracted by adjusting the border using the Clip function (Figure 1). At this time, the size of the segmentation area was set to be approximately 1700 μm X 1600 μm X 500 μm (width X depth X height). Within the segmented area, the fibers and the non-fiber portions were distinguished based on contrast using the lower otsu function and the upper otsu function of Dragonfly software (Figure 2). The lower otsu function identified the low-contrast segmented area corresponding to the non-fiber portion, and the upper otsu function distinguished the high-contrast segmented area corresponding to the fiber portion. Then, the volume fraction (volume ratio) of fibers and non-fibers was calculated using Dragonfly software (Fig. 3). Through the above analysis, the non-compressive, 150 N / cm was measured for five specimens for each example or comparative example. 2 or 300 N / cm 2After compression with a pressure of , the volume ratio of the fibers per unit volume of the aerogel composite and the volume ratio of the remaining area excluding the fibers (i.e., the area occupied by the aerogel including voids and pores between the discrete fibers) were measured. Then, the average value of the measured volume ratios for five specimens for each example or comparative example was calculated and shown in Tables 2 to 4 below. In addition, in order to confirm the change in the volume ratio of the aerogel including voids and pores according to the compression, the rate of change in the volume ratio after compression with respect to the volume ratio of the aerogel including voids and pores when not compressed was calculated and the results are shown in Table 5 below.

[0216] Volume fraction of air-containing aerogel between compressed fibers + voids (%) (C) Fiber volume fraction (%) Example 191.68.4 Example 292.527.48 Example 390.139.87 Example 493.686.32 Example 595.274.73 Comparative Example 191.248.76 Comparative Example 290.189.82 Comparative Example 388.6511.35 Comparative Example 493.026.98 Comparative Example 585.4714.53

[0217] Classification 150 N / cm 2 Compressed fibers inter-pore + volume fraction of aerogel containing pores (%) (D) Fiber volume fraction (%) Example 180.08 19.92 Example 287.03 12.97 Example 386.52 13.48 Example 483.45 16.55 Example 585.81 14.19 Comparative example 175.03 24.97 Comparative example 273.56 26.44 Comparative example 370.3 29.7 Comparative example 469.92 30.08 Comparative example 570.46 29.54

[0218] Classification 300 N / cm 2Compressed fibers inter-pore + volume fraction of aerogel containing pores (%) (E) Fiber volume fraction (%) Example 178.0421.96 Example 284.7115.29 Example 381.0418.96 Example 477.1922.81 Example 576.923.1 Comparative example 171.0128.99 Comparative example 268.731.3 Comparative example 362.5637.44 Comparative example 464.3835.62 Comparative example 563.8136.19

[0219] Change rate of the volume ratio (times) 150N / 0N 300N / 0N Example 10.874236 0.851965 Example 20.94066 10.915586 Example 30.959947 0.899146 Example 40.890798 0.823975 Example 50.90070 30.80718 Comparative Example 10.822337 0.778277 Comparative Example 20.81570 20.76181 Comparative Example 30.79300 60.705697 Comparative Example 40.751666 0.692109 Comparative Example 50.82438 30.746578

[0220] As shown in Tables 2 to 5 above, the aerogel composites (Examples 1 to 5) according to the present invention have a very high volume ratio of aerogel including voids and pores between discrete fibers per unit volume of the aerogel composite compared to the aerogel composites of Comparative Examples 1 to 5, and the strength of the aerogel including pores is excellent, reaching 150 N / cm. 2 It was confirmed that even when compressed at high pressure, the change in volume ratio was small, and specifically, it was maintained at more than 0.85 times the volume ratio before compression.

[0221]

[0222] [Experimental Example 2] Analysis of thermal transmittance after compression of aerogel composites

[0223] Using the aerogel composites obtained in Examples 1 to 5 and Comparative Examples 1 to 5, specimens with a size of 30 cm X 24 cm in length X width were prepared, and then compressed for 10 minutes under each pressure condition using QM900A-15T press equipment from QMESYS Co., Ltd. Before and after compression, the thickness and thermal conductivity of the aerogel composites were measured using HFM436 equipment from Netzsch Co., Ltd., and the thermal transmittance was calculated. In addition, in order to confirm the change in the thermal transmittance before and after compression, 150 N / cm for the thermal transmittance before compression 2 or 300 N / cm 2 The ratio of thermal transmittance after compression was calculated by the century, and the results are shown in Table 6 below. In addition, in order to evaluate the change in thermal transmittance before and after compression, the ratio of thermal transmittance before and after compression was calculated by the non-compression (0 N / cm 2 ), 150 N / cm 2 and 300 N / cm 2 The average value (b) of the thermal transmittance measured after compression is calculated, and as shown in Equation 2 below, no compression or 150 N / cm 2 and 300 N / cm 2 The difference between the thermal transmittance (a) measured after compression at each pressure and the average value (b) of these thermal transmittances, and the value A, which is the difference divided by the average value (b) of the thermal transmittances, were calculated and the results are shown in Table 7. The pressure values ​​shown in Tables 6 and 7 below are the values ​​of the pressure applied per unit area of ​​the specimen, and mean the value obtained by dividing the area of ​​the specimen obtained by multiplying the cylinder area of ​​the press equipment by the set pressure value as in Equation 1 below. The cylinder radius of the QM900A-15T press equipment used in this experiment is 6.25 cm, and the cylinder size is 12.5 cm. In addition, each result value in the table below is rounded off from the third decimal place and shown to the second decimal place.

[0224] [Formula 1]

[0225] Actual pressure value = (Inner cylinder radius of press equipment X Inner cylinder radius of press equipment X 3.14 X Set pressure value) / (Area of ​​specimen)

[0226] [Formula 2]

[0227] {(Thermal transmittance before and after compression (a)) - (Average of thermal transmittances before and after compression (b))} = (Average of thermal transmittances before and after compression (b)) XA

[0228] Thermal transmittance (W / m) 2 K) Change in heat transfer coefficient (times) 0150 N / cm 2 300 N / cm 2 150N / 0N300N / 0NExample 16.528.028.661.231.33Example 23.313.754.151.131.25Example 35.235.676.271.081.20Example 44.685.917.131.261.52Example 53.223.954.961.231.54Comparative Example 16.2711.7813.731.882.19Comparative Example 26.0411.5713.591.922.25Comparative Example 37.4213.5217.881.822.41Comparative Example 44.269.6416.392.263.85Comparative example 57.8115.0621.311.932.73

[0229] Thermal transmittance (a) before and after compression (W / m) 2 K) Average values ​​of thermal transmittances before and after compression (b) (W / m 2 K) Deviation of thermal transmittance before and after compression (ab) (W / m 2 K) Deviation of thermal transmittance before and after compression / average thermal transmittance (ab / b = A) Example 106.527.73-1.21-0.16150 N / cm 2 8.020.290.04300 N / cm 2 8.660.930.12Example 203.313.74-0.43-0.11150 N / cm 2 3.750.010.00300 N / cm 2 4.150.410.11 Example 305.235.72-0.49-0.09150 N / cm 25.67-0.05-0.01300 N / cm 2 6.270.550.10 Example 404.685.91-1.23-0.21150 N / cm 2 5.910.000.00300 N / cm 2 7.131.220.21 Example 503.224.04-0.82-0.20150 N / cm 2 3.95-0.09-0.02300 N / cm 2 4.960.920.23Comparative example 106.2710.59-4.32-0.41150 N / cm 2 11.781.190.11300 N / cm 2 13.733.140.30Comparative example 206.0410.40-4.36-0.42150 N / cm 2 11.571.170.11300 N / cm 2 13.593.190.31Comparative example 307.4212.94-5.52-0.43150 N / cm 2 13.520.580.04300 N / cm 2 17.884.940.38Comparative example 404.2610.10-5.84-0.58150 N / cm 2 9.64-0.46-0.05300 N / cm 2 16.396.290.62Comparative example 507.8114.73-6.92-0.47150 N / cm 2 15.060.330.02300 N / cm 2 21.316.580.45

[0230] As shown in Tables 6 and 7 above, the aerogel composites of Examples 1 to 5 according to the present invention have a strength of 150 N / cm when compared to the aerogel composites of Comparative Examples 1 to 5. 2 Even when compressed to the above century, the increase in the thermal transmittance of the aerogel composite compared to before compression was small, and it was confirmed that the change in the thermal transmittance was small and the insulation performance was maintained at an excellent level even when compressed to various pressure values ​​from relatively low to high pressure.

[0231]

[0232] [Reference Experimental Example 1] Analysis of Recovery Rate after Compression of Aerogel Composites

[0233] In the above Experimental Example 2, when measuring the thermal transmittance after compression for the aerogel composites of the examples and comparative examples, the thickness of the aerogel composite was measured using the HFM436 equipment of Netzsch before compression and after 1 hour after the end of compression under each pressure condition, and the compression recovery rate was calculated according to the following Equation 4, and the results are shown in Table 8 below.

[0234] [Formula 4]

[0235] Compression recovery rate (%) = {(cross-sectional thickness of aerogel composite after compression) / (cross-sectional thickness of aerogel composite before compression)} X 100

[0236] Thickness recovery rate after compression under different pressure conditions (%) Example 10-150 N / cm 2 81.29%300 N / cm 2 78.56% Example 20-150 N / cm 2 76.20%300 N / cm 2 74.51% Comparative Example 10-150 N / cm 2 74.84%300 N / cm 2 70.96% Comparative Example 40-150 N / cm 2 62.51%300 N / cm 2 58.47%

[0237] From the above results, it was found that it is difficult to see that the change in the thickness of the aerogel composite before and after compression shows the same trend as the change in the volume ratio of the aerogel and the voids including the pores in the aerogel composite before and after compression or the change in the thermal transmittance.

[0238] From these results, it was confirmed that the aerogel composite of the present invention has a high volume ratio of voids between aerogel containing a large number of pores and discrete fibers that substantially provide an insulating effect, and has excellent strength of the aerogel pores, so that even when compressed at high pressure, a rapid decline in insulating performance due to pore destruction is prevented, and excellent insulating performance is maintained even after compression.

[0239] The present invention relates to an aerogel composite and its use as an insulating material.

Claims

1. A substrate comprising a plurality of discrete fibers and voids between the fibers; and An aerogel composite comprising a silica aerogel having a network structure including one or more pores and a plurality of aerogel particles positioned on the fibers and in the voids between the fibers, 150 N / cm in the thickness direction for the above aerogel composite 2 An aerogel composite, wherein when pressure is applied, the volume ratio of the voids between the aerogel and the discrete fibers including pores per unit volume of the aerogel composite is 0.85 times or more and 1 times or less than that before applying the pressure.

2. In paragraph 1, An aerogel composite, wherein the volume ratio of the aerogel and the voids including pores per unit volume of the aerogel composite is 88 to 98%.

3. In paragraph 1, An aerogel composite, wherein the total volume ratio of the fibers per unit volume of the aerogel composite is 2 to 12%.

4. In paragraph 1, 300 N / cm in the thickness direction for the above aerogel composite 2 An aerogel composite, wherein when pressure is applied, the volume ratio of aerogel and pores per unit volume of the aerogel composite is 0.80 to 1 times greater than that before applying pressure.

5. In paragraph 4, 300 N / cm in the thickness direction for the above aerogel composite 2 When a pressure of , the volume ratio of aerogel and pores per unit volume of the aerogel composite is 150 N / cm 2 An aerogel composite having a pressure of 0.89 times or more and 1 times or less compared to that when pressure is applied.

6. In paragraph 1, In order to compress the above aerogel composite, 150 N / cm in the thickness direction of the aerogel composite 2 More than 300 N / cm 2 An aerogel composite having a thermal transmittance after compression that is less than twice the thermal transmittance before compression when the pressure below is applied.

7. In paragraph 6, 150 N / cm for the cross section of the above aerogel composite 2 An aerogel composite having a thermal transmittance after compression of 1.8 times or less compared to the thermal transmittance before compression when pressure is applied.

8. In paragraph 6, 150 N / cm for the cross section of the above aerogel composite 2 An aerogel composite having a thermal transmittance after compression that is more than 1 and less than 1.5 times the thermal transmittance before compression when pressure is applied.

9. In paragraph 6, 300 N / cm for the cross section of the above aerogel composite 2 An aerogel composite having a thermal transmittance after compression that is less than twice that before compression when pressure is applied.

10. In paragraph 6, 300 N / cm for the cross section of the above aerogel composite 2 An aerogel composite having a thermal transmittance after compression that is more than 1 and less than 1.8 times the thermal transmittance before compression when pressure is applied.

11. In paragraph 6, 150 N / cm for the cross section of the above aerogel composite 2 and 300 N / cm 2 An aerogel composite having a thermal transmittance after compression that is more than 1 time and less than 2 times the thermal transmittance before compression when pressure is applied.

12. In paragraph 6, To compress the above aerogel composite, 150 N / cm for the aerogel composite 2 and 300 N / cm 2 An aerogel composite whose thermal conductivity before and after compression when compressed by applying each pressure satisfies the following equation 2: [Formula 2] {(Thermal transmittance before and after compression (a)) - (Average of thermal transmittances before and after compression (b))} = (Average of thermal transmittances before and after compression (b)) XA In the above equation 2, the thermal transmittance (a) before and after compression is 0 N / cm in the thickness direction of the aerogel composite. 2 , 150 N / cm 2 or 300 N / cm 2 It means the thermal transmittance obtained after compression by the century, and the average value (b) of the thermal transmittances before and after compression is the thermal transmittance of the unpressurized aerogel composite and 150 N / cm for the aerogel composite. 2 and 300 N / cm 2 It means the average value of the thermal transmittance obtained after compression by the century, and the above A is a real number from - 0.30 to + 0.

30.

13. In paragraph 12, An aerogel composite, wherein A is a real number between -0.25 and +0.

25.

14. In paragraph 6, 150 N / cm for the above aerogel composite 2 or 300 N / cm 2 The rate of change in the thermal transmittance after compression (B) per unit applied pressure obtained after compression when each pressure was applied satisfies the following equation 3, an aerogel composite: [Formula 3] B = │(Thermal transmittance after compression at pressure x - Thermal transmittance after compression at pressure y) / (x - y)│ In the above equation 3, x is 150 N / cm 2 or 300 N / cm 2 is the pressure of , y is 0, and B is greater than or equal to 0 and 2.0 X 10 -2 The following is a mistake.

15. In paragraph 14, The above x is 150 N / cm 2 , y is 0, and B is greater than or equal to 0 and 1.5 X 10 -2 The following is an example of an aerogel composite.

16. In paragraph 14, The above x is 300 N / cm 2 , y is 0, and the above B is greater than or equal to 0 and 1.0 X 10 -2 The following is an example of an aerogel composite.

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

18. In paragraph 1, The density of the above aerogel composite is 0.15 to 0.35 g / cm 3 In, aerogel composite.

19. An insulating member comprising an aerogel composite according to any one of claims 1 to 18.

20. In paragraph 19, An insulating member, wherein the insulating member further includes a support member positioned on at least one of the upper and lower surfaces of the aerogel composite.

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