Aerogel composition for heat insulation

Abstract

The thermal control member contains a mixture of a) silica aerogel particles having a particle size in the range of 0.1 mm to 5 mm and b) hydrophobic silica-containing particles having at least 30 methanol values and a particle size D50 of 100 microns or less. In this mixture, the particle size distribution of the silica-containing particles has at least two peaks. The silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 1:99 to 99:1, and the thermal control member has a thermal conductivity at 25 °C of 5 to 30 mW / m·K and a thickness of 0.1 to 10 mm.

Description

Technical Field

[0001] The present invention relates to an aerogel blend composition for heat insulation, and particularly to an aerogel blend composition for heat insulation of a multi-cell rechargeable battery.

Background Art

[0002] Aerogel particles can have a very low density, high porosity, and small pore size. Aerogels, particularly silica aerogels, are useful as insulating materials because they exhibit low density and low thermal conductivity. Aerogels can be formed by removing the solvent from a hydrogel by methods such as supercritical drying technology or a method combining solvent replacement and atmospheric drying. Silica aerogels are typically hydrophilic but can be made hydrophobic by using specific treatment agents.

[0003] In the broadest sense, i.e., when considered as "a gel having air as the dispersion medium", aerogels are produced by drying a suitable gel. When used in this sense, the term "aerogel" includes narrow-sense aerogels such as xerogels and cryogels. When the temperature at which the liquid is removed from the gel is higher than the critical temperature and starts from a pressure higher than the critical pressure, the gel is called a narrow-sense aerogel. In contrast, when the liquid is removed from the gel subcritically, for example, with the formation of a gas-liquid interface phase, the resulting gel is often called a xerogel. It should be noted that the gel according to the present invention is an aerogel in the sense that it is a gel having air as the dispersion medium.

[0004] Insulating articles are used in a variety of applications to provide an insulating layer. For example, insulating articles or thermal control members in the form of panels or blankets are used in applications including, but not limited to, construction, refrigerators, material handling (e.g., to insulate pipes), and rechargeable batteries. Aerogels and / or other particles can be used in these insulating articles to impede heat conduction, suppress heat loss due to infrared radiation, and provide other desirable properties. Additionally, these insulating articles can have additional components such as glass fibers to provide additional functions such as mechanical integrity and flame retardancy.

[0005] The degree of insulation provided by an article is reduced by components of the thermal control member that provide non-insulating functions. Therefore, it is desirable to have a thermal control member in which insulating particles are incorporated to compensate for the effects of other components on thermal properties. SUMMARY OF THE INVENTION

[0006] The thermal control member includes a mixture of a) silica aerogel particles having a particle size in the range of 0.1 mm to 5 mm and b) hydrophobic silica-containing particles having a methanol value of at least 30 and a particle size D50 of 100 microns or less, wherein in this mixture, the particle size distribution of the silica-containing particles has at least two peaks. The silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 1:99 to 99:1, and the thermal control member has a thermal conductivity at 25°C of 5 to 30 mW / m·K and a maximum thickness of 10 mm.

[0007] The hydrophobic silica-containing particles can be selected from the group consisting of silica aerogel, fumed silica, silicon-treated carbon black, silica-coated carbon black, fumed mixed metal oxides, precipitated silica, silica-carbon black composite particles, rice husk silica, and sol-gel silica. For example, the hydrophobic silica-containing particles can be selected from the group consisting of silica aerogel, fumed silica, and sol-gel silica. The hydrophobic silica-containing particles may be hydrophobized by silicone fluid, cyclic siloxane, hydrophobized silane, functionalized silane, or silazane. The hydrophobic silica-containing particles may be hydrophobic fumed silica particles having a surface area of 30 to 550 m 2 / g, preferably 30 to 250 m 2 / g.

[0008] The hydrophobized silane may be R 4-n SiX n (wherein n is 1 to 3, each R is independently selected from the group consisting of hydrogen, C1-C30 branched and linear alkyl or alkenyl groups, C3-C18 haloalkyl groups, C3-C10 cycloalkyls, and C6-C14 aromatic groups, and each X is independently a C1-C18 branched or linear alkoxy group or halo). The functionalized silane can contain at least one functional group selected from the group consisting of acrylate, methacrylate, amino, anhydride, epoxy, halogen, hydroxyl, sulfur, vinyl, isocyanate, and combinations thereof. The particle size D50 of the hydrophobic silica-containing particles may be from 0.1 micron to 100 microns.

[0009] The mixture can further contain fibers. The fibers may be glass fibers, ceramic fibers, synthetic polymer fibers, carbon fibers, natural polymer fibers, mineral wool, or a mixture of two or more of these. The fibers may be blackened or coated with a metal.

[0010] An opacifying agent can be incorporated into at least a part of the silica aerogel present in the thermal control member. At least a part of the silica aerogel may be coated or impregnated with a heat-absorbing material. The mixture can further comprise one or more components selected from the group consisting of fibers, opacifying agents, fire retardants, heat-absorbing materials, phase change materials, binders, defoamers, dispersants, emulsifiers, surfactants, and flocculants.

[0011] The thermal control member can further comprise a sheet or mat containing silicone, polyvinylidene fluoride, chlorinated polyethylene, aramid fiber, or aramid aerogel. The thermal control member can further comprise an envelope enclosing the mixture. The thermal control member may be in the form of a blanket or a press pad. The thermal control member can meet the UL94 V0 specification.

[0012] It should be understood that both the foregoing general description and the following detailed description are merely exemplary and explanatory and are not intended to further limit the claimed invention.

Mode for Carrying Out the Invention

[0013] The thermal control member comprises a mixture of a) silica aerogel particles having a particle size in the range of 0.1 mm to 5 mm and b) hydrophobic silica-containing particles having a methanol value of at least 30 and a particle size D50 of 100 microns or less, wherein in this mixture, the particle size distribution of the silica-containing particles has at least two peaks. The silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 1:99 to 99:1, and the thermal control member has a thermal conductivity at 25°C of 5 to 30 mW / m·K and a maximum thickness of 10 mm.

[0014] Any type of silica aerogel particles can be used in the mixture. The aerogel can be formed as described in U.S. Patent No. 7,470,725. Suitable aerogels can be made from water glass or organic materials such as TEOS and TMOS. To reduce the effect of radiation on thermal conductivity, IR opacifying agents such as carbon black, alumina, graphite, titanium dioxide, iron oxide, silicon carbide, zirconium dioxide, or mixtures thereof can be incorporated into the aerogel particles. Aerogel particles are available from various suppliers, including the ENOVA and ENTERA brands of Cabot Corporation, and the AEROVA brand of JIOS Aerogel.

[0015] The silica aerogel of component a) can have a particle size in the range of 0.1 mm to 5 mm, such as 0.1 mm to 4 mm, 0.1 mm to 1.5 mm, 0.5 mm to 4 mm, or 1 mm to 4 mm. The aerogel can have a narrow or wide particle size distribution and can be in the form of crushed powder. The particle size can be measured by sieving.

[0016] Various hydrophobic silica aerogels can be used. A hydrophobic silica aerogel is an aerogel that exhibits a water contact angle greater than 90 degrees. Examples include, but are not limited to, aerogels commercially available from Cabot Corporation. Specific commercially available types include, but are not limited to, the ENOVA® brand aerogel, ENTERA brand aerogel, and P100 and P200 aerogels available from Cabot Corporation. Since the aerogel is preferably pre-formed before assembly of the aerogel-containing envelope, any desired aerogel structure, morphology, or other properties can be selected, and these properties can essentially be present in the final product. Aerogel particles are also commercially available as mixtures with opacifying agents such as carbon black.

[0017] In some embodiments, aerogel particles having a porosity higher than about 60% and a density of less than about 0.4 g / cc can be used. In other embodiments, the aerogel particles may have a density of about 0.05 to about 0.15 g / cc. The thermal conductivity of the aerogel particles may be less than about 40 mW / m·K, less than about 25 mW / m·K, or about 12 mW / m·K to about 18 mW / m·K, or less. To reduce flammability, for example, the aerogel particles may be low-calorie aerogels such as those having a calorie content of less than about 10 MJ / kg, less than about 8 MJ / kg, less than about 7 MJ / kg, or less than about 6 MJ / kg. The aerogel particles may be present in an amount of 10 wt% to 90 wt% based on the total dry weight of the mixture. This amount may be 20 wt% to 80 wt%, 30 wt% to 70 wt%, 40 wt% to 70 wt%, 50 wt% to 90 wt%, 60 wt% to 90 wt%, 10 wt% to 30 wt%, 10 wt% to 40 wt%, or any range based on any two values described herein.

[0018] The hydrophobic silica-containing particles may be a second silica aerogel or hydrophobic silicon-treated carbon black, silica-coated carbon black, silica-carbon black composite particles, fumed silica, fumed mixed metal oxide, hydrophobic precipitated silica, rice husk silica, or sol-gel silica. Preferably, the hydrophobic silica-containing particles are a second silica aerogel or hydrophobic fumed silica. Hydrophobic silicon-treated carbon black, silica-coated carbon black, silica-carbon black composite particles, or titania-containing mixed metal oxide can be used to introduce infrared absorption ability into the heat control member. The methanol value of the hydrophobic silica-containing particles may be at least 30, for example, at least 35, at least 40, at least 50, at least 60, or at least 70, or may be 35 to 80. The methanol value can be measured using a Rhesca Wet-101P powder wettability tester (Rhesca Co., Ltd.) according to the manufacturer's instructions, using 60 mL of the starting solution, a stirring speed of 300 rpm, and a methanol flow rate of 2 mL / min. Before adding the sample, the starting solution is degassed by stirring at 1000 rpm for at least 5 minutes. The measurement is typically performed using 0.1 g of the sample in a starting solution of 30% methanol. However, depending on the hydrophobicity of the sample, a starting solution that is more or less hydrophobic can be used. The test is performed by titrating the starting solution with methanol. The methanol value is the amount of methanol in the solution when the sample, which was initially floating on the starting solution, begins to wet or sink into the solution and can be automatically calculated by the apparatus. Alternatively, the threshold methanol value of the powder can be determined by carefully pouring the sample onto the surface of a methanol-aqueous solution having a known methanol concentration. If the sample does not wet in the solution, the methanol value of the sample is higher than the methanol concentration in the solution.

[0019] The hydrophobic silica-containing particles have a particle size D50 (volume basis) smaller than that of the silica aerogel, preferably 100 microns or less, for example, 0.1 micron to 95 microns, 1 micron to 90 microns, 5 microns to 20 microns, 10 microns to 30 microns, 20 microns to 40 microns, or 30 microns to 60 microns, 40 microns to 70 microns, 60 microns to 80 microns, or 70 microns to 100 microns. For example, the second silica aerogel can be ground, classified, and / or crushed so as to yield aerogel particles having a size smaller than that of the (first) silica aerogel particles. Exemplary silica aerogel particles for use as the second silica aerogel include, but are not limited to, TLD201 and TLD203 silica aerogels of Cabot Corporation. The silica aerogel particles and the hydrophobic silica-containing particles can be present in a mass ratio of 1:99 to 99:1, for example, 80:20 to 20:80, 35:65 to 65:35, 40:60 to 60:40, or 45:65 to 65:45.

[0020] When the hydrophobic silica-containing particles are the second silica aerogel, the aerogel can be an aerogel of the same or different type or composition as the (first) silica aerogel, except that it should have different particle sizes as described above. For example, the second silica aerogel may be from the same or a different manufacturer as the first aerogel, or may have the same or different additives as the first aerogel.

[0021] Alternatively, or in addition, the hydrophobic silica-containing particles may be hydrophobic fumed silica or calcined silica. Fumed silica typically has a particle size of 2-20 nm and is formed from the gas phase. In one manufacturing process, silica (usually sand) is evaporated at about 2000 °C and cooled to form anhydrous amorphous silica particles. Alternatively, silica can be sublimated at about 1500 °C in the presence of a reducing agent (e.g., coke) to form SiO, and SiO can be oxidized to form particulate silica. Other methods of manufacturing fumed silica include, for example, the oxidation of SiCl4 at high temperature, or the combustion of SiCl4 in the presence of methane or hydrogen.

[0022] A well-established process for manufacturing fumed metal oxides involves the hydrolysis of a suitable feedstock vapor (e.g., aluminum chloride in the case of fumed alumina, silicon tetrachloride in the case of fumed silica) in a flame of hydrogen and oxygen. In the combustion process, substantially spherical molten particles are formed, and the particle diameter can be varied by controlling the process parameters. These molten spheres, called primary particles, collide at the points of contact of their spheres and fuse together to form branched three-dimensional chain aggregates. The formation of aggregates is considered to be irreversible as a result of the fusion between primary particles. During cooling and recovery, the aggregates can undergo further collisions, resulting in some mechanical entanglement to form agglomerates. These agglomerates are thought to be weakly bound by van der Waals forces and can be reversibly reacted, i.e., deaggregated, by being suitably dispersed in a suitable medium or by grinding, for example, in a jet mill or a hammer mill.

[0023] For example, alternative methods for manufacturing calcined silica particles have been developed as described in U.S. Patent Nos. 4,755,368, 6,551,567, and 6,702,994, U.S. Patent Application Publication No. 2011 / 0244387, Mueller, et al., "Nanoparticle synthesis at high production rates by flame spray pyrolysis," Chemical Engineering Science, 58:1969 (2003), Naito, et al., "New Submicron Silica Produced by the Fumed Process," published in NIP 28: International Conference on Digital Printing Technologies and Digital Fabrication 2012, 2012, pp. 179-182, and Kodas and Hampden-Smith, Aerosol Processing of Materials, Wiley-VCH, 1998 (the entire contents of all of which are incorporated by reference). Other methods for preparing calcined silica particles are known.

[0024] In some embodiments, the calcined silica for use in the thermal control members described herein is 30-550 m 2 / g, for example, 75-150, 150-250, 250-350, or 350-400 m 2It has a BET surface area such as / g. The particle size of the calcined silica used in this specification indicates the size of the agglomerate. The particle size can be measured using a Malvern Mastersizer 3000 equipped with an Aero S dry powder accessory module. The sample is conveyed at a constant speed in a compressed air stream operated at a compressed air supply pressure of 0.05 MPa (0.5 bar). Appropriate feed rates and laser obscuration are maintained throughout the analysis to obtain an acceptable signal-to-noise ratio that provides reliable data. Those skilled in the art will recognize that appropriate feed rates and laser obscuration may vary for different fine particles. The appropriate obscuration for fumed silica is typically in the range of 0.4 - 3.0%. The D50 of fumed silica is typically 5 - 40 microns, but may be smaller if the fumed silica is ground. Any hydrophobic fumed silica having a D50 of 100 microns or less can be used.

[0025] Both hydrophilic fumed silica and hydrophobic fumed silica that can be surface-treated for use in the embodiments shown in this specification are commercially available. Non-limiting examples of fumed silica include CAB-O-SIL fumed silica available from Cabot Corporation, HDK fumed silica products available from Wacker Chemie AG, and AEROSIL fumed silica available from Evonik Industries (Essen, Germany).

[0026] Alternatively, or in addition, silica-containing particles containing other materials can also be used. For example, silica-coated carbon black can be used. Exemplary silica-coated carbon blacks include those described in U.S. Patent No. 6,541,113, U.S. Patent No. 6,197,274, and U.S. Patent No. 9,598,560 (the entire contents of all of which are incorporated herein by reference). Silicon-treated carbon blacks having a silica phase and a carbon phase can also be used. Methods for producing and surface-treating various types of silicon-treated carbon blacks are described in U.S. Patent Nos. 7,199,176; 6,709,506; 6,686,409; 6,534,569; 6,469,089; 6,448,309; 6,364,944; 6,323,273; 6,211,279; 6,169,129; 6,057,387; 6,028,137; 6,008,272; 5,977,213; 5,948,835; 5,919,841; 5,904,762; 5,877,238; 5,869,550; 5,863,323; 5,830,930; 5,749,950; 5,747,562; 5,622,557; and 6,929,783; and U.S. Patent Application Publication No. 2002 / 0027110 (all of which are incorporated herein by reference in their entirety). Carbon black-silica composite particles such as those described in U.S. Patent No. 10,800,925 (the entire contents of which are incorporated herein by reference) can also be used. Co-fumed silica particles such as silica-titania or silica-alumina mixed oxides can also be used. Exemplary hydrophilic and hydrophobic mixed oxides are disclosed in U.S. Patent No. 5,424,258, U.S. Patent No. 6,197,469, U.S. Patent No. 7,083,769, U.S. Patent Application Publication No. 20100016490, U.S. Patent Application Publication No. 20050239921, U.S. Patent No. 6,328,944, U.S. Patent No. 4,297,143, and U.S. Patent No. 7,897,256 (the entire contents of all of which are incorporated herein by reference).Any of these silica-containing materials that are not already hydrophobic can be surface-treated in the same manner as fumed silica or precipitated silica as described below.

[0027] Precipitated metal oxide particles can be produced using conventional techniques and are often formed by coagulating the desired particles from an aqueous medium under the influence of high salt concentrations, acids, or other coagulants. The metal oxide particles are filtered, washed, dried, and separated from the residues of other reaction products by conventional techniques known to those skilled in the art. The precipitated particles are often aggregated in the sense that a number of primary particles coagulate with each other to form somewhat spherical agglomerate clusters. Non-limiting examples of commercially available precipitated metal oxides include the Hi-Sil® products of PPG Industries, Inc., and the SIPERNAT® products available from Degussa Corporation.

[0028] Sol-gel metal oxide particles, sometimes called colloidal metal oxide particles, are often non-aggregated and discrete (primary) particles, typically spherical or nearly spherical, but can also have other shapes (e.g., shapes with a generally elliptical, square, or rectangular cross-section). Sol-gel metal oxides can be commercially available or prepared by known methods from various starting materials (e.g., wet process type metal oxides). Sol-gel metal oxide particles are typically produced in a similar manner to precipitated metal oxide particles (i.e., coagulated from an aqueous medium), but remain dispersed in a liquid medium (often water alone, or water containing a co-solvent and / or stabilizer). Metal oxide particles can be prepared, for example, from silicic acid derived from an alkali silicate solution having a pH of about 9 to about 11. The silicate anions undergo polymerization to produce discrete silica particles having a desired average particle size in the form of an aqueous dispersion. Typically, the metal oxide starting material is available as a sol. The sol is one in which the metal oxide is dispersed in a suitable solvent, which is most often water alone, or water containing a co-solvent and / or stabilizer. References: For example, Stoeber, et al., "Controlled Growth of Monodisperse Silica Spheres in the Micron Size Range," Journal of Colloid and Interface Science, 26, 1968, pp. 62-69, Akitoshi Yoshida, Silica Nucleation, Polymerization, and Growth Preparation of Monodispersed Sols, in Colloidal Silica Fundamentals and Applications, pp 47-56 (H.E. Bergna & W.O. Roberts, eds., CRC Press: Boca Raton, Florida, 2006) and Iler, R.K., The Chemistry of Silica, p 866 (John Wiley & Sons: New York, 1979).Non-limiting examples of commercially available sol-gel metal oxides suitable for use in the present invention include SNOWTEX® products from Nissan Chemical, LUDOXY® products available from W.R. Grace & Co., NexSil™ and NexSil A™ series products available from Nyacol Nanotechnologies, Inc., Quartron™ products available from Fuso Chemical, and Levasil® products available from AkzoNobel.

[0029] The sol-gel metal oxide particles can have a primary particle size of about 5 to about 100 nm, for example, about 5 to about 10 nm, about 10 to about 20 nm, about 20 nm to about 30 nm, about 30 to about 50 nm, or about 50 to about 70 nm. The metal oxide particles can be spherical or non-spherical. For example, the aspect ratio of the metal oxide particles can be about 1.5 to about 3, for example, about 1.5 to about 1.8, about 1.8 to about 2.1, about 2.1 to about 2.5, about 2.5 to about 2.8, or about 2.8 to about 3. The particle size can be measured by the dynamic light scattering method.

[0030] Hydrophobic rice husk silica can also be used. Rice husk silica is obtained from rice husks and can be produced by acid extraction followed by combustion, sedimentation, or the sol-gel method. Hydrophobic rice husk silica can be in the form of an aerogel as described in Chinese Patent Application Publication No. 101348255, European Patent No. 1689676, or International Publication No. 2022117618. Hydrophobic rice husk silica can also be prepared by the methods described in Chinese Patent Application Publication No. 102583403 or Chinese Patent Application Publication No. 1880384, by calcination, or by other methods known to those skilled in the art.

[0031] In certain embodiments, the hydrophobic silica-containing particles can be produced by treating hydrophilic particulate silica, such as fumed silica, precipitated silica, or sol-gel silica, with a surface treatment agent known to those skilled in the art. The silica treatment agent can be any suitable silica treatment agent and can either covalently bond to the surface of the silica particles or exist as a non-covalent coating. Typically, the silica treatment agent binds to the silica either covalently or non-covalently. In many cases, the silica treatment agent can be a silicone fluid, such as an unfunctionalized silicone fluid or a functionalized silicone fluid, a cyclic siloxane, a hydrophobizing silane, a functionalized silane, a silazane, or other silica treatment agents known in the art, for example.

[0032] In certain embodiments, the silica treatment agent comprises a hydrophobizing silane. For example, the silica treatment agent has the formula: R 4-n SiX n(wherein n is from 1 to 3, each R is independently selected from the group consisting of hydrogen, C1-C30 branched and straight-chain alkyl or alkenyl groups, C3-C18 haloalkyl groups, C3-C10 cycloalkyls, and C6-C14 aromatic groups, and each X is independently a C1-C18 branched or straight-chain alkoxy group or halo). In certain embodiments, the silica treating agent comprises a functionalized silane. The functionalized silane can comprise at least one functional group selected from the group consisting of acrylate, methacrylate, amino, anhydride, epoxy, halogen, hydroxyl, sulfur, vinyl, isocyanate, and combinations thereof. In certain embodiments, the silica treating agent comprises a silazane, for example, the silica treating agent can be a cyclic silazane such as hexamethyldisilazane, octamethyltrisilazane, those disclosed in U.S. Patent No. 5,989,768, etc. The treatment of fumed silica can also effect a reversal of the charge of the particles, for example, a reversal from negative to positive. Preferred hydrophobic treating agents for silica for use as hydrophobic silica-containing particles in various embodiments herein include hexamethyldisilazane, alkyltrialkoxysilanes and alkyldialkoxysilanes, for example, octamethyltrimethoxysilane, hexamethyldisiloxane, dimethyldichlorosilane, and siloxane compounds including, but not limited to, cyclic siloxanes, silicone fluids, and siloxane polymers including polydimethylsiloxane, and functionalized siloxane polymers including monofunctional and bifunctional hydroxyl-terminated PDMS and methylhydrogensiloxane and / or methylhydroxylsiloxane polymers.

[0033] The hydrophilic particulate silica can be surface-treated using any suitable method known to those skilled in the art. For example, sol-gel silica can be surface-treated using techniques such as those described in U.S. Patent Nos. 7,811,540; 8,202,502; 8,435,474; 8,455,165; 10,407,571; and 8,895,145, the entire contents of which are incorporated by reference. The dry silica particles can be surface-treated using wet or dry techniques known to those skilled in the art. For example, the dry treatment method can include agitating or mixing a metal oxide and a hydrophobizing agent in a fluidized bed reactor. Alternatively, the wet treatment method can include dispersing a metal oxide in a solvent to form a metal oxide slurry and adding a hydrophobizing agent to the slurry to modify the metal oxide surface with the hydrophobizing agent. Additionally, the charge-modified metal oxide can be prepared using a batch process or a continuous process, where the dry metal oxide is thoroughly mixed and contacted with a liquid hydrophobizing agent or a vapor hydrophobizing agent. In a preferred embodiment, the mixture is then held at a temperature sufficient to modify the surface properties of the metal oxide for a certain period of time.

[0034] A mixture of silica aerogel and hydrophobic silica-containing particles may be used in combination with or in conjunction with one or more fibers. The fibers can impart strength and mechanical resilience, can reduce flammability, and can help prevent the particles from settling after installation. The fibers can be natural fibers, synthetic fibers, or both. Glass fibers and ceramic fibers can be used. The fibers can be of uniform length or can be a mixture of fibers of different lengths.

[0035] The glass and ceramic fibers that can be used in various embodiments of this specification may be composed of various inorganic oxides such as SiO2, Al2O3, B2O3, Na2O, K2O, CaO, and MgO. Detailed fibers can include one, two, three, four, or more of these oxides. In some embodiments, the fibers can be, for example, glass fibers such as borosilicate (B fibers) obtainable from Lauscha Fiber International, calcium aluminoborosilicate (E fibers), and / or, for example, fibers consisting essentially of silica (Q fibers) obtainable from Johns Manville. Other types of fibers that can be used in specific embodiments include synthetic non-carbon fibers, mineral wool, wollastonite, carbon fibers, ceramics, cellulose, cotton, polyvinyl alcohol (PVA), polybenzimidazole, polyaramide, acrylic, phenol, polypropylene, other types of polyolefins, or organic fibers such as aramid fibers, nylon fibers, or thermoplastic fibers, but are not limited thereto. The fibers can also be coated with, for example, a metallized polyester fiber with a metal such as aluminum. A mixture of two or more fibers can also be used.

[0036] The length and diameter of the fibers can be varied according to the specific application. In some embodiments, two or more different types of fibers can be used such that the fiber length distribution exhibits a bimodal or multimodal distribution. The fiber length can range from 0.5 cm to 50 cm or more, for example, in the range of 0.5 - 2 cm, 1 - 15 cm, or 0.5 - 5 cm. The fibers can have a thickness of from less than 1 nm to more than 1 mm, for example, 1 nm - 100 nm, 100 nm - 1000 nm, 1 micron - 10 microns, 10 microns - 50 microns, or 50 microns - 1 mm. It is understood that the fiber diameter may not be uniform. The aspect ratio (length:diameter) of the fibers can be at least 100:1, for example, 1000:1 - 10000:1. The fibers can be of any configuration known to those skilled in the art. For example, the fibers can be in the form of chopped fibers, microfibers, woven fibers, or non-woven fibers.

[0037] The fibers can have any cross-sectional shape. The fibers can be circular, polygonal, trilobal, pentalobal, octalobal, strip-shaped, or can be in the shape of a fir tree, dumbbell, etc. The fibers can have a diameter that is uniform or varies along the length of the fiber. In some embodiments, hollow fibers can be used. Further, the fiber material can be smooth, crimped, curled, or straight. In certain embodiments, the fibers can be modified with additives, such as antistatic agents like carbon black. The fibers can also contain IR opacifying agents such as carbon black, titanium dioxide, alumina, iron oxide, or zirconium dioxide, silicon carbide, and mixtures thereof, to reduce the effect of radiation on the thermal conductivity.

[0038] In addition to including an IR opacifying agent, the effect of radiation on thermal conductivity can be further reduced by using blackened fibers such as polyester fibers blackened with carbon black or simply carbon fibers. The mechanical strength of the thermal control member can also be affected by the length and distribution of the fibers in the composition. To reduce the increase in thermal conductivity caused by the added fibers, the proportion of the fibers (by weight) can be maintained at the minimum concentration required to achieve the desired mechanical strength. The amount of fibers used can be 1% to 99%, for example, 5% to 95%, 10% to 90%, 20% to 30%, 30% to 40%, 40% to 50%, 50% to 60%, 60% to 70%, 70% to 80%, or 80% to 90% based on the total components of the thermal control member, depending on the density, diameter, and length of the fibers. In certain embodiments, the fibers may constitute more than 1 wt%, more than 3 wt%, more than 5 wt%, or more than 10 wt% of the thermal control member. In other embodiments, the fibers may occupy less than 5 wt%, less than 3 wt%, or less than 1 wt% of the thermal control member. The thermal conductivity of the fibers may be from about 0.01 to about 1 W / m·K, preferably less than about 1 W / m·K.

[0039] Alternatively, or in addition, an opacifying agent, such as an infrared opacifying agent, can be used in combination with or combined with the mixture to reduce radiative heat transfer. An IR opacifying agent is a material that reduces the transmission of infrared rays, and examples thereof include carbon black, mica, alumina, graphite, titanium dioxide, rutile sand, iron oxide, silicon carbide (SiC), graphite, or zirconium dioxide. Examples of suitable titanium dioxides of different types include, for example, Tipure® (DuPont) and Altiris® (Huntsman). The IR opacifying agent can be used individually or as a mixture of two or more compounds. The IR opacifying agent can be added in an amount that provides the target level of IR transmission reduction in the thermal control member. These levels can be, for example, 2% to 150%, 5% to 100%, or 10% to 40% of the opacifying agent, based on the weight of the mixture of silica aerogel and hydrophobic silica-containing particles. Opacifying agents of two or more different average particle sizes and / or compositions can be used in a single embodiment to cover a wider range of IR wavelengths.

[0040] In some embodiments, the thermal control member can include a flame retardant or a fire retardant. The concentration of the fire retardant and / or flame retardant in some embodiments can range from 0.1 wt% to 5.0 wt%, 0.2 wt% to 2.0 wt%, and 0.3 wt% to 1.5 wt% with respect to the mass of the thermal control member. The flame retardant can be, for example, an alkali oxide, an alkaline earth metal oxide, aluminum trihydrate, magnesium hydroxide, antimony oxide, titanium dioxide, rutile sand, a melamine compound, a phosphate-based or halogen-based compound. In certain embodiments, the titanium dioxide particles can have a diameter of about 1.18 μm, 0.9 to 1.3 μm, 0.8 to 1.4 μm, or 0.5 to 4.0 μm, and in certain embodiments, the particle size distribution can have a d50 of about 1.0 μm + / - 0.01 μm, + / - 0.02 μm, or + / - 0.05 μm. Examples of halogenated flame retardants include brominated flame retardants (BFRs) such as organic bromine compounds including polymeric organic bromine compounds. In some other embodiments, the flame retardant has a structure with a high ratio of heteroatoms to carbon atoms. For example, in some embodiments, the heteroatom:carbon atom ratio can be greater than 0.5:1, greater than 1:1, or greater than 2:1, and in certain embodiments, the heteroatom can be nitrogen and / or sulfur. The flame retardant and / or fire retardant can be incorporated into the thermal control member at a concentration sufficient to suppress flammability or meet specifications such as UL94-V0. Alternatively, or in addition, embodiments of the thermal control member can exhibit a calorie content of, for example, less than 10 MJ / kg, less than 8 MJ / kg, less than 5 MJ / kg, less than 3 MJ / kg, less than 2 MJ / kg, or less than 1 MJ / kg, for example, 0.5 MJ / kg or 1 MJ / kg to 5 MJ / kg. The flame retardant or fire retardant can be incorporated into a mixture of silica aerogel and hydrophobic silica-containing particles.

[0041] Alternatively, or in addition, the thermal control member can further include a heat absorbing material. Such a material helps the thermal control member function not only as an insulator that retards heat transfer but also as a heat capacitor that can store thermal energy. Examples of such heat absorbing materials can include aluminum hydroxide and others known to those skilled in the art. Alternatively, or in addition, the heat absorbing material can include a phase change material that stores heat by undergoing a thermodynamic phase transition. The heat absorbing material may be incorporated into a mixture of silica aerogel and hydrophobic silica-containing particles, attached to the surface of the aerogel particles in the mixture, or otherwise impregnated into the pores of the aerogel particles.

[0042] Alternatively, or in addition, the thermal control member can include an additional sheet-like material to improve mechanical integrity, heat resistance, mechanical elasticity, and / or other properties. Examples include silicone-based materials, polyvinylidene fluoride, chlorinated polyethylene, aramid materials such as Kevlar (e.g., a woven mat of aramid fibers), and Kevlar nanofiber aerogels such as those described in Lyu, et al., ACS Nano 2019, 13, 2236-2245, but are not limited thereto. A woven mat of Kevlar or other aramid fibers may be impregnated with a shear thickening fluid as described in U.S. Patent No. 7,825,045, the content of which is incorporated herein by reference.

[0043] Alternatively, or in addition, the mixture of silica aerogel and hydrophobic silica-containing particles can further include a binder. Suitable binders include silicone, polyvinyl alcohol, polyvinylidene fluoride, polyethylene terephthalate, polybutylene terephthalate, acrylate polymers, and other heat-resistant and / or flame-retardant polymers known to those skilled in the art. The binder can help prevent extensive dispersion or dissipation of the silica aerogel, hydrophobic silica-containing particles, and other particulate components of the thermal control member in the event of a catastrophic failure or explosion of the insulated article, such as a battery. A binder such as polyvinyl alcohol can also bind additives such as carbon black to the aerogel particles to reduce dusting during assembly. The binder may be mixed with some or all of the components of the mixture, including any additives incorporated into the mixture, using an impeller or other suitable device known to those skilled in the art. Preferably, the binder renders the aerogel blanket nonflammable by UL94 or other flammability test methods.

[0044] Alternatively, or in addition, the mixture of silica aerogel and hydrophobic silica-containing particles can further include a processing aid. Suitable processing aids are determined by the method of manufacture and form of the thermal control member. Suitable processing aids include, but are not limited to, antifoaming agents, surfactants, dispersants, and emulsifiers.

[0045] In some embodiments, the mixture is encapsulated within an envelope. The envelope functions to prevent powdering, assist in maintaining the shape of the heat control member, facilitate the operation or installation of the heat control member, and / or perform other useful functions known to those skilled in the art. The material forming the envelope is preferably a flame retardant and / or heat resistant polymer. Exemplary polymers include silicone, polyvinylidene fluoride (PVDF), chlorinated polyethylene, and other similar polymers known to those skilled in the art. Alternatively, or in addition, the envelope material can include reinforcing fibers such as aramid fibers to impart tear resistance. The reinforcing material may be used in combination with other polymers, or the entire envelope may be formed of such a polymer, for example a woven fabric of aramid fibers.

[0046] The heat control article may take any form known to those skilled in the art. For example, a fiber-containing blanket or pad can be made using techniques such as those described in, for example, U.S. Patent No. 9,399,864, U.S. Patent Application Publication No. 2021 / 0363699, International Publication No. 2022 / 024085, Chinese Patent Application Publication No. 112759353, U.S. Patent No. 11,274,044, Chinese Patent Application Publication No. 112681009, Chinese Patent Application Publication No. 113943171, Chinese Patent Application Publication No. 110093783, Chinese Patent Application Publication No. 112681009, JP 2015048543, and / or U.S. Patent Application Publication No. 2020 / 0295328 (the entire contents of all of which are incorporated herein by reference). In one embodiment, such as that described in U.S. Patent No. 9,399,864, an aqueous slurry is prepared using a mixture of silica aerogel, hydrophobic silica-containing particles, glass fibers, and other desired components of the blanket or pad (e.g., binders, opacifiers, fire retardants, defoamers, etc.). A charged compound or other emulsifier or dispersant is added to the slurry to form an emulsion, which is then coagulated with a coagulant. The resulting flock is collected on a scrim or belt and dehydrated. An airlaid process can also be used in which silica aerogel, hydrophobic silica-containing particles, fibers, and other desired components (e.g., opacifiers, fire retardants, etc.) are combined with air and then deposited on an air-permeable scrim. In these embodiments, the fibers may be polymer fibers that can be melted to hold the blanket or pad together, or silicone or other binders may be sprayed or otherwise applied to one or both sides of the blanket or pad and activated by heating to hold these components together. Exemplary airlaid methods that can be adapted to manufacture a blanket or pad according to the embodiments herein include, but are not limited to, those disclosed in U.S. Patent No. 4,083,913, U.S. Patent Application Publication No. 2004 / 192136, and U.S. Patent No. 6,479,416 (the contents of all of which are incorporated herein by reference).

[0047] In another embodiment, the mixture, binder, and any other desired components, such as glass fibers, are filled into a mold and pressed onto a pad as described, for example, in European Patent No. 3835262, the entire content of which is incorporated herein by reference. It may be necessary to heat or otherwise activate the polymer binder within the mold. Alternatively, or in addition, the mixture, binder, and other components may be formulated into a paste and extruded as described, for example, in European Patent No. 3835262 and International Publication No. 2020228998, the entire contents of which are incorporated herein by reference. Alternatively, or in addition, the mixture may be incorporated into or combined with a polymer foam as described in International Publication No. 2020211320, Japanese Unexamined Patent Application Publication No. 2020019925, and / or U.S. Patent No. 10640629, the entire contents of all of which are incorporated herein by reference.

[0048] Alternatively, the mixture and any other desired components are used to fill an envelope or other cavity using techniques such as those described in Chinese Patent Application Publication No. 113785431, Chinese Patent Application Publication No. 110544809, JP 2012145204, and / or US Patent Application Publication No. 20210332932, the entire contents of which are incorporated herein by reference. Another suitable technique is to fill an envelope or bag held in a suitably spaced mold with the mixture. The mold is manually compressed, for example using clamps, and then preferably evacuated. For thinner envelopes, it may be desirable to use aerogels of smaller diameter to facilitate free flow throughout the bag. Alternatively, the mass of material required to produce the desired mass density in an envelope or pouch of a particular volume can simply be filled into the envelope without using a mold. The envelope can then be compressed with a roller to distribute the mixture evenly throughout the bag. In a preferred embodiment, for example, a film or sheet of polyethylene terephthalate or silicone is placed in a mold on a vibrating table, the mold having a cavity is filled with the mixture, and a portion of the film or sheet is overhung over the cavity. The mold is vibrated and compressed at 8 - 12 psi using a plate to pack the mixture. A top sheet (or film) large enough to cover the cavity and the overhanging portion is placed on top, and three sides of the overhanging portion are sealed with the top sheet. Air is exhausted from the resulting envelope, and the fourth side is sealed. In fact, when the envelope provides the desired mechanical support, certain components such as fibers and binders may not be necessary. In fact, in some embodiments, it may only be desirable to have the aerogel within the envelope with any optional opacifying agent and / or hydrophobic silica-containing particles.

[0049] The thermal control member may be manufactured in a substantially planar or flat form for insertion between cells of a rechargeable battery, such as a lithium-ion battery. The evacuated envelope can be made slightly thinner than the space in which the envelope is installed. When installed, the envelope can puncture to relieve the vacuum, thereby expanding until it is under compression. As the battery expands and contracts, the thermal control member also freely expands and contracts. Alternatively, or in addition, the envelope need not be manufactured as a flat or sheet-like object and may be manufactured in a specific shape. For example, the thermal control article may be shaped to be disposed around a particular component within the battery or other device and may have a more complex shape.

[0050] In some embodiments, the thermal control article includes an additional sheet-like material to improve mechanical integrity, heat resistance, mechanical elasticity, and / or other properties. Examples include, but are not limited to, silicone-based materials, polyvinylidene fluoride, chlorinated polyethylene, aramid materials such as Kevlar (e.g., a woven mat of aramid fibers), and Kevlar nanofiber aerogels such as those described in Lyu, et al., ACS Nano 2019, 13, 2236-2245. A woven mat of Kevlar or other aramid fibers may be impregnated with a shear-thickening fluid as described in U.S. Patent No. 7,825,045, the contents of which are incorporated herein by reference.

[0051] In some cases, an envelope can be used that serves roles such as preventing loose powder, helping to maintain the shape of the heat control article, and facilitating its operation or installation. The material forming the envelope is preferably a flame-retardant and / or heat-resistant polymer material, including, for example, silicone, polyvinylidene fluoride (PVDF), chlorinated polyethylene, and other similar polymers known to those skilled in the art. Alternatively, or in addition, the material of the envelope can include reinforcing fibers such as aramid fibers to impart fracture resistance. The reinforcing material may be used in combination with other polymers, or the entire envelope may be formed of such a polymer, for example, a woven fabric of aramid fibers.

[0052] The heat control member may have a thickness of 0.1 to 10 mm, for example, 0.5 to 8 mm, 1 to 5 mm, or 1.5 to 3 mm. In some embodiments, at least a portion of the component is compressed, for example, between rollers or platens, during the assembly of the heat control member to reduce the thickness of the final article.

[0053] The heat control member can exhibit excellent thermal stability. For example, the heat control member may shrink by less than 2% after aging at 650 °C in accordance with ASTM-C356. The thermal conductivity of the heat control member at 25 °C in accordance with test method ASTM C518 may be less than 30 mW / m·K, preferably less than 25 mW / m·K, more preferably less than 20 mW / m·K, for example, 5 mW / m·K to 20 mW / m·K or 8 mW / m·K to 15 mW / m·K or 15 mW / m·K to 25 mW / m·K.

[0054] The heat control article can be flexible, which is a property that can be measured in accordance with ASTM C1101 or another suitable technique. A manual bend test can be particularly useful, especially at the initial screening stage of the product.

[0055] In certain implementations, the heat control article is a blanket having a nonflammable flammability rating in accordance with UL94-V0.

[0056] The present invention will be further clarified by the following examples, which are intended to be merely illustrative in nature.

Example

[0057] Example 1 A vacuum bag (VAC-Master) was cut and resealed using an impulse sealer to form a bag defining an 8-inch by 8-inch square opening. The insulating pads were prepared by combining the components listed in Table 1 in either a Flacktek DAC600 Speedmixer (formulation without glass fibers) or a high-speed stainless steel Waring blender (formulation with glass fibers). The glass fibers were 6mm E-glass chopped fibers with a diameter of 6 microns from Lauscha Fiber International. A total of 10.53 g of material was used for each pad. Any mixture was a 50 / 50 mixture by mass. The various particles are described in Table 2 below and the particles are from Cabot Corporation. All have trimethylsilyl groups on their surfaces. The resulting mixture was spread evenly in the sized vacuum bag using a spatula until the thickness of the bag reached the thickness shown in Table 1. Air was removed from the bag, the vacuum time was set to 20 seconds, the sealing time was set to 1.2 seconds, and the cooling time was set to 2 seconds, and the open end of the bag was sealed with a VAC-Master VP320 according to the manufacturer's instructions. The thermal conductivity and thickness were measured using a Lasercomp (trademark) FOX200 (Waters / TA Instruments) in accordance with ASTM C518. "Vacuum" indicates measurements at 25 °C (15 °C on the cold side and 35 °C on the hot side) on samples prepared and compressed between two plates with a pressure of about 1 psi. "Pop" means a hole made in the bag to allow air to permeate through the bag. However, the compression of the sample was not released and the amount of air that could enter the bag was limited, and the pressure rose above 1 psi. "No vacuum" means that the compression of the bag was partially released after "popping" to allow the air pressure to equalize inside the bag and keep the bag compressed at a pressure of about 1 psi.

Table 1

Table 2

Table 3

[0058] Example 3 A bag (VacMaster Vacuum Chamber Pouch, approximately 150 mm x 200 mm, with 3 mil (0.76 mm) thick walls) open at one end was placed into a mold with a 5 mm gap. The mold was prepared by clamping two pieces of 3 / 4 inch (19 mm) plywood, each approximately 9.5 inches (24.1 cm) square, on either side with spacers (two paint stirrers) to create an appropriately sized cavity. ENTERA EV5200 aerogel was filled into the bag, with vibration and tamping of the mold used to ensure complete filling of the bag. The filled bag was manually compressed with a load of approximately 5 psi and then evacuated using a Vacmaster VP320 meat packer until approximately 90% vacuum was achieved. The evacuated pouch had a pressure of approximately 110 kg / m 3 The thermal conductivity and thickness were measured as above to be 15.96 mW / m K and 6 mm.

[0059] Example 4 A bag of the same design as in Example 3 was filled with a predetermined weight of ENTERA EV5200 aerogel. The desired weight was 110 kg / m for a 150 mm x 200 mm x 4 mm pouch. 3 The weight was the weight needed to achieve a final density of 1.2 kg / m². The filled bag was then manually compressed with a roller using two rails to maintain the filled bag at the desired thickness of approximately 5 mm. The roller was rolled back and forth until the aerogel appeared to be evenly dispersed. The pack was then placed in a Vacmaster VP320 meat packer, evacuated, and then tested for thermal conductivity and thickness in the same manner as in Example 1. The initial thickness was initially 3.8 mm and increased to 4.1 mm after the vacuum was released. The thermal conductivity was measured to be 16.30 mW / m·K.

[0060] Example 5 Dispersant (Jeffamine M2070 dispersant, Huntsman), Nalclear 71605 rheology modifier (Nalco), and Foamkill™ 830 antifoaming agent (Crucible Chemical) were dispersed in water, and 2 liters of a white (process) aqueous concentrate was formed in a WARING bench top heavy duty blender according to the formulation in Table 5. Mixing was carried out at high shear for 10 seconds to form process water. Ceramic fiber (Fiberfrax® 7001 C5 ceramic fiber, Unifrax, a high purity, coarsely cut product having an average fiber diameter of 1.5 - 2.5 microns and a fiber index of 45 - 55% as measured by conical elutriation), P200 aerogel particles (Cabot Corporation), fumed silica (all of the Cabot Corporation's CAB-O-SIL brand as shown in Table 4, properties are described in Table 4, D50 are all 5 - 20 microns), 44 micron rutile titania sand (Loudwolf), F600 6 micron silicon carbide (Sturbridge Metallurgical Services), and aluminum trihydroxide (ATH, Sigma Aldrich) were added to the WARING heavy duty blender in the amounts listed in Table 5. The mixture in the blender was mixed at high shear (15000 rpm) for 20 seconds to form a paste-like dispersion. Acrylic binder (Novacryl PSR 300, Synthomer) and silicone binder (Dowsil HV 496 resin, Dow) were added to the blender and mixed at high shear for an additional 20 seconds to make a slurry. To destabilize the slurry system, a flocculant (polydiallyldimethylammonium chloride (PDADMAC) from Sigma Aldrich, 30% solution) was added to the slurry to generate flocs. Typically, an amount of flocculant (shown in Table 5) of 4 - 5 grams was added to the dispersion until a dense flocculant layer was formed on top.

[0061] After flocculation, the slurry was discharged through a single-layer wet-laying forming wire to produce a 30 cm × 30 cm blanket sheet. Next, the blanket and the forming wire were passed through a vacuum to remove excess water from the aerogel flock. The sample was passed through a roll press to squeeze out some of the water and compress various components into a more compact form. All the blankets were placed in a drying oven at 120 °C for about 20 minutes.

[0062] The blankets were evaluated for several properties. Thermal conductivity and thickness were measured in accordance with ASTM C518 using a LaserComp Heat Flow Meter instrument. Also, the samples were evaluated according to the UL94 flammability standard. The results are shown in Table 6, indicating that surface treatment can bring about an improvement in thermal conduction performance without impairing the combustion performance.

Table 4

Table 5

Table 6

Table 7

[0063] Example 6 The blanket has a BET surface area of about 86 m 2 / g, a D50 of 9 microns, a methanol wettability of 65 - 70, and is produced as described in Example 5 using CAB-O-SIL TG-6110G silica having trimethylsilyl groups on the surface and CAB-O-SIL TG5180 silica having a BET surface area of about 35 m 2 / g, a D50 of 5 - 40 microns, and a methanol wettability higher than 70 and treated with polydimethylsiloxane on the surface. The resulting blanket is expected to have a thermal conductivity of 20 - 30 and a UL94 rating of V0.

[0064] The foregoing description of the preferred embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims

1. a) a thermal control member comprising a mixture of silica aerogel particles having a particle size in the range of 0.1 mm to 5 mm and b) hydrophobic silica-containing particles having a methanol value of at least 30 and a particle size D50 of 100 microns or less, wherein in the mixture, the particle size distribution of the silica-containing particles has at least two peaks, the silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 1:99 to 99:1, the thermal conductivity of the thermal control member at 25 °C is about 5 to 30 mW / m·K, and the thickness is 0.1 to 10 mm.

2. The thermal control member according to claim 1, wherein the hydrophobic silica-containing particles are selected from the group consisting of silica aerogel, fumed silica, silicon-treated carbon black, silica-coated carbon black, fumed mixed metal oxide, precipitated silica, silica-carbon black composite particles, rice husk silica, and sol-gel silica.

3. The thermal control member according to claim 1 or 2, wherein the hydrophobic silica-containing particles are selected from the group consisting of silica aerogel, fumed silica, precipitated silica, and sol-gel silica.

4. The thermal control member according to any one of claims 1 to 3, wherein the hydrophobic silica-containing particles are hydrophobized by a silicone fluid, a cyclic siloxane, a hydrophobized silane, a functionalized silane, or a silazane.

5. The hydrophobic silica-containing particles have a surface area of 30 to 550 m 2 / g, preferably 30 to 250 m 2 / g and are hydrophobic fumed silica particles, and the heat control member according to any one of claims 1 to 4.

6. wherein the hydrophobic silane is R 4-n SiX n (wherein n is 1 to 3, each R is independently selected from the group consisting of hydrogen, C1-C30 branched and linear alkyl or alkenyl groups, C3-C18 haloalkyl groups, C3-C10 cycloalkyl groups, and C6-C14 aromatic groups, and each X is independently a C1-C18 branched or linear alkoxy group or halo), the heat control member according to any one of claims 1 to 5.

7. The thermal control member according to any one of claims 1 to 6, wherein the functionalized silane contains at least one functional group selected from the group consisting of acrylate, methacrylate, amino, anhydride, epoxy, halogen, hydroxyl, sulfur, vinyl, isocyanate, and combinations thereof.

8. The thermal control member according to any one of claims 1 to 7, wherein the particle size D50 of the hydrophobic silica-containing particles is 0.1 micron to 100 microns.

9. The thermal control member according to any one of claims 1 to 8, wherein the mixture further comprises fibers.

10. The thermal control member according to any one of claims 1 to 9, wherein the fibers are glass fibers, ceramic fibers, synthetic polymer fibers, carbon fibers, natural polymer fibers, mineral wool, or a mixture of two or more of these.

11. The thermal control member according to any one of claims 1 to 10, wherein the fibers are blackened or coated with a metal.

12. The thermal control member according to any one of claims 1 to 11, wherein an opacifying agent is incorporated into at least a part of the silica aerogel present in the thermal control member.

13. The thermal control member according to any one of claims 1 to 12, wherein at least a part of the silica aerogel is coated or impregnated with a heat-absorbing material.

14. The thermal control member according to any one of claims 1 to 13, wherein the mixture further contains one or more components selected from the group consisting of a fiber, an opacifying agent, a fire retardant, a heat-absorbing material, a phase change material, a binder, an antifoaming agent, a dispersant, an emulsifier, a surfactant, and a flocculant.

15. The thermal control member according to any one of claims 1 to 14, further comprising a sheet or mat containing silicone, polyvinylidene fluoride, chlorinated polyethylene, aramid fiber, or aramid aerogel.

16. The thermal control member according to any one of claims 1 to 15, further comprising an envelope for enclosing the mixture.

17. The thermal control member according to any one of claims 1 to 16, wherein the thermal control member is in the form of a blanket or a press pad.

18. The thermal control member according to any one of claims 1 to 17, wherein the thermal control member meets the UL94 V0 specification.

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