Silica particle composition for thermal insulation

Abstract

A composition comprising 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 grape-like particles having a methanol number of 30 to 70 and a carbon content of up to 6 wt.%, wherein the silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 0:100 to 80:20; and wherein the heat control component has a thermal conductivity of about 5-40 mW / m.K at 25 °C and a thickness of 0.1-10 mm.

Description

Technical Field

[0001] This invention relates to silica-containing particulate compositions (i.e. compositions comprising silica-containing particles) for thermal insulation, particularly for multi-cell rechargeable batteries. Background Technology

[0002] Aerogel particles can possess very low density, high porosity, and small pore diameter. Aerogels, especially silica aerogels, exhibit low density and low thermal conductivity, making them suitable for use as insulating materials. Aerogels can be formed by removing the solvent from a hydrogel, for example, through supercritical drying techniques or by solvent displacement combined with ambient pressure drying. Silica aerogels are typically hydrophilic, but can be made hydrophobic by using specific treatment agents.

[0003] In its broadest sense, that is, when considered as a "gel with air as a dispersant," an aerogel is produced by drying a suitable gel. When used in this sense, the term "aerogel" includes aerogels in a narrower sense, such as dry gels and cryogels. A gel is called an aerogel in a narrower sense if the liquid is removed from it at a temperature above the critical temperature and a pressure above the critical pressure. Conversely, if the liquid is removed from the gel subcritically, for example, forming a liquid-gas boundary phase, the resulting gel is often called a dry gel. It should be noted that the gel according to the invention is an aerogel because it is a gel with air as the dispersion medium.

[0004] Due to its excellent insulating properties, aerogels have been incorporated into various types of articles, including thermal control articles (such as sheets, mats, or blankets) designed for applications such as construction, refrigeration, and pipeline transportation. One application of increasing interest involves the insulation of rechargeable batteries in electric vehicles (EVs).

[0005] US9399864 discloses a wet-laid aerogel blanket produced from a slurry of aerogel particles and a polymer binder. CN112430018 discloses a fiber paper impregnated with aerogel retained by a silica binder. CN112522949 discloses an aerogel mat in which an aerogel slurry is injected into a glass fiber mat, and then the glass fiber mat is impregnated in a slurry containing a polymer curing agent. CN112681009 discloses a bilayer paper system impregnated with an organic solution of silica aerogel. There remains a need for thin aerogel blankets that maintain thermal conductivity and tensile strength while having a reduced aerogel content while maintaining thermal insulation properties. Summary of the Invention

[0006] In one embodiment, the composition 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 aciniform particles having a carbon content of up to 6% by weight and a methanol value of 30 to 70 (preferably 45 to 70), wherein the silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 0:100 to 80:20; and wherein the composition has a thermal conductivity of about 5-40 mW / mK at 25°C and a thickness of 0.1-10 mm.

[0007] The grape-like particles containing hydrophobic silica can be selected from pyrolytic silica, silicon-treated carbon black, silica-coated carbon black, pyrolytic mixed metal oxides, and silica-carbon black composite particles. For example, the particles containing hydrophobic silica can be hydrophobic pyrolytic silica. The particles containing hydrophobic silica can be hydrophobized using hydrophobic silanes or silazanes. The particles containing hydrophobic silica can be surface-treated with a silica treatment agent and have a particle size of 60 to 340 μm. 2 / g (preferably 60 to 250 mg) 2 Pyrolytic silica particles with a surface area of ​​ / g.

[0008] Hydrophobic silanes can be R 4-n SiX n Where n is 1-3, each R is independently selected from hydrogen, C1-C30 branched or straight-chain alkyl or alkenyl, C3-C18 haloalkyl, C3-C10 cycloalkyl, and C6-C14 aromatic groups, preferably C1-C4 branched or straight-chain alkyl or alkenyl, and each X is independently C1-C18 branched or straight-chain alkoxy or halogen, wherein no more than three groups R are hydrogen.

[0009] The mixture may further comprise fibers, such as glass fibers, ceramic fibers, synthetic polymer fibers, carbon fibers, natural polymer fibers, mineral wool, or mixtures of two or more of these. The fibers may be blackened or metal-coated.

[0010] At least a portion of the silica aerogel present in the heat control component may be combined with a light-blocking agent and / or covered or impregnated with a heat-absorbing material.

[0011] The mixture may further include one or more components selected from fibers, opacifiers, flame retardants, heat-absorbing materials, phase change materials, adhesives, defoamers, dispersants, emulsifiers, surfactants, and flocculants.

[0012] The composition may further include sheets or felts comprising silicone, polyvinylidene fluoride, chlorinated polyethylene, aromatic polyamide fibers, or aromatic polyamide aerogels.

[0013] The composition may further include an encapsulation material for encapsulating the mixture.

[0014] The heat control component may contain the composition and may be in the form of a blanket or a pressed pad.

[0015] The thermal control components meet the UL94 V0 standard.

[0016] The composition may further include materials such as IR shielding agents, fire retardants or flame retardants, phase change materials, heat absorbers, processing aids, etc. In the manufacture of heat control products, binders, water, dispersants, emulsifiers, flocculants, etc., may be included as needed.

[0017] The above and other features of the invention, including various details of the structure and combinations of components, as well as other advantages, will now be described in more detail with reference to the accompanying drawings and pointed out in the claims. It should be understood that the specific methods and apparatus embodying the invention are shown by way of illustration and not as a limitation thereof. The principles and features of the invention may be employed in various and many embodiments without departing from the scope of the invention. Detailed Implementation

[0018] The invention will now be described more fully below with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0019] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Furthermore, all conjunctions used should be understood in the most inclusive sense possible. Thus, the word “or” should be understood to have the definition of logical “or” rather than logical “exclusive”, unless the context explicitly states otherwise. Additionally, unless explicitly stated otherwise, the singular form and the articles “a,” “an,” and “the” are also intended to include the plural form. It will be further understood that, when used in this specification, the terms “comprising,” “including,” “containing,” and / or “containing” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Furthermore, it should be understood that when an element comprising a component or subsystem is referred to and / or shown as connected or coupled to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements present.

[0020] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms such as those defined in common dictionaries shall be interpreted as having the same meaning as their meaning in the context of the relevant field and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein. Unless otherwise stated, all proportions and percentages are by weight.

[0021] In one embodiment, the composition or thermal control component 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 grape-like particles having a methanol value of 30 to 70 (preferably 45 to 70) and a carbon content of up to 6% by weight, wherein the silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 0:100 to 80:20; and wherein the thermal control component has a thermal conductivity of about 5-40 mW / mK at 25°C and a thickness of 0.1-10 mm. Preferably, the composition is a silica-containing particulate composition, meaning that the composition comprises silica-containing particles.

[0022] Any type of silica aerogel particles can be used in the mixture. The aerogel can be formed as described in US7470725. Suitable aerogels can be made from water glass or organic materials such as TEOS and TMOS. To reduce the radiative contribution to thermal conductivity, the aerogel particles can be combined with IR-shielding agents such as carbon black, alumina, graphite, titanium dioxide, iron oxide, silicon carbide, zirconium dioxide, or mixtures thereof. Aerogel particles are available from a variety of sources, including those under the trademarks ENOVA and ENTEA from Cabot Corporation and those under the trademark AEROVA from JIOS Aerogel.

[0023] Silica aerogels can have particle sizes ranging from 0.1 mm to 5 mm, for example, 0.1 mm to 4 mm, 0.1 mm to 0.5 mm, 0.1 mm to 1 mm, 0.1 mm to 1.5 mm, or 1 mm to 4 mm. Aerogels can have narrow or wide particle size distributions and can be in the form of pulverized powder. The diameter of the aerogel particles can be measured along the longest cross-sectional line of a given particle, or the particle size range can be measured by sieving.

[0024] Silica aerogel particles can be hydrophobic, exhibiting a water contact angle greater than 90 degrees. Examples of commercially available aerogels include aerogels under the trademarks ENOVA® and ENTEA®, as well as IC3110, P100, P150, and P200 aerogels, all from Cabot Corporation. Aerogel particles are also commercially available as mixtures with opacifiers such as carbon black. In some embodiments, the aerogel particles have a porosity greater than about 60% and a density less than about 0.4 g / cc. In other embodiments, the aerogel particles have a density of about 0.05 to about 0.15 g / cc.

[0025] The thermal conductivity of aerogel particles at 25°C can be less than about 40 mW / mK, less than about 25 mW / mK, or about 12 mW / mK to about 18 mW / mK, or lower. To reduce flammability, aerogel particles can be low-calorific-content aerogels, such as those having a calorific value of, for example, less than 10 MJ / kg, less than 8 MJ / kg, less than 7 MJ / kg, or less than 6 MJ / kg.

[0026] Since aerogels are preferably preformed (prepared prior to the manufacture of the composition or heat-controlled article), any desired aerogel structure, morphology, or other properties can be selected, and these properties can generally persist in the final product.

[0027] The grape-like particles containing hydrophobic silica (i.e., aggregates resembling a bunch of grapes formed by the fusion of primary particles) can be hydrophobic silicon-treated carbon black, silica-coated carbon black, silica-carbon black composite particles, pyrolytic silica, or pyrolytic mixed metal oxides. The particle aggregates can be further linked to form agglomerates. Preferably, the grape-like particles containing hydrophobic silica are hydrophobic pyrolytic silica. Alternatively or additionally, hydrophobic silicon-treated carbon black, silica-coated carbon black, silica-carbon black composite particles, or titanium dioxide-containing mixed metal oxides can be used to introduce infrared absorption capabilities to thermal control components. The carbon content of the hydrophobic silica can be up to 6% by weight, for example, 0.5-4.5% by weight or 0.6-4.2% by weight. The carbon content can be measured by burning silica in a pure oxygen environment and determining the concentration of the resulting carbon dioxide gas. Suitable instruments for this analysis include those commercially available from LECO Corporation and others known to those skilled in the art. Alternatively or additionally, the methanol value of the hydrophobic silica-containing particles can be from 30 to 70, preferably 45-70. The methanol value can be measured using a Rhesca Wet-101P powder wettability tester (Rhesca Co. Ltd.) according to the manufacturer's instructions, using a 60 mL starting solution, a stirring rate of 300 rpm, and a methanol flow rate of 2 mL / min. The starting solution is degassed by stirring at 1000 rpm for at least 5 minutes before adding the sample. Measurements are typically performed with 0.1 g of sample in a 30% methanol starting solution. However, depending on the hydrophobicity of the sample, a more or less hydrophobic starting solution 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 initially at the top of the starting solution begins to wet or sink into the solution, and can be calculated automatically by the instrument. Alternatively, the threshold methanol value of the powder can be determined by carefully pouring the sample onto a surface of a methanol-water solution with a known methanol concentration. If the sample does not wet into the solution, its methanol value is higher than the methanol concentration in the solution.

[0028] The ratio of silica aerogel particles to hydrophobic silica-containing grape-like particles (aerogel: grape-like particles) is 0:100 to 80:20, for example 5:95 to 70:30, 10:90 to 60:40, 20:80 to 55:45, 30:70 to 50:50, or 40:60 to 75:25. The amount of silica-containing particles in the composition or thermal control component can be 10% to 70% by weight, for example 15% to 65% by weight, 20% to 60% by weight, 25% to 55% by weight, 30% to 50% by weight, or 35% to 45% by weight.

[0029] In some embodiments, prior to any surface hydrophobication treatment, the silica-containing grape-like particles used for the thermal control components described herein have a size of 60 μm. 2 / g to 340m 2 / g, preferably 60m 2 / g to 250m 2 / g, more preferably 60m 2 / g to 150m 2 / g BET surface area. As the surface area increases, the effect of hydrophobic botryoidal silica on the tensile strength of thermal control components in the form of blankets (e.g., wet-laid blankets) changes from positive to negative.

[0030] Preferably, the grape-like particles containing hydrophobic silica can be hydrophobic pyrolytic or igneous silica. Pyrolytic silica typically has a primary particle size of 2-20 nm and is formed in the gas phase. In one manufacturing process, silica (typically 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, which can then be oxidized to form granular silica. Other methods for producing pyrolytic silica include, for example, oxidizing SiCl4 at high temperatures or burning SiCl4 in the presence of methane or hydrogen.

[0031] Documented processes for producing pyrolytic metal oxides involve hydrolyzing suitable feedstock vapors (e.g., aluminum chloride for pyrolytic alumina, or silicon tetrachloride for pyrolytic silica) in a flame of hydrogen and oxygen. During combustion, generally spherical molten particles are formed, and the particle diameter can be varied by controlling process parameters. These molten spheres, referred to as primary particles, fuse together by colliding at their contact points to form branched, three-dimensional chain-like aggregates. Due to the fusion between primary particles, aggregate formation is considered irreversible. During cooling and collection, the aggregates undergo further collisions, which may lead to some mechanical entanglement to form agglomerates. These agglomerates are thought to be loosely held together by van der Waals forces and can be reversed (i.e., deagglomerated) by proper dispersion in a suitable medium or by grinding (e.g., in a jet mill or hammer mill).

[0032] Alternative methods for producing igneous silica particles have been developed, such as, for example, U.S. Patent Nos. 4,755,368, 6,551,567, and 6,702,994, U.S. Patent Publication No. 20110244387, “Nanoparticle synthesis at high production rates by flame spray pyrolysis” by Mueller et al., Chemical Engineering Science, 58: 1969 (2003), “New Submicron Silica Produced by the Fumed Process” by Naito et al., NIP 28: International Conference on Digital Printing Technologies and Digital Fabrication 2012, 2012, pp. 179-182, and Aerosol Processing of Materials by Kodas and Hampden-Smith, Wiley-VCH, 1998, the contents of all of which are incorporated herein by reference. Other methods for preparing igneous silica particles are known.

[0033] Both hydrophobic pyrolytic silica and hydrophilic pyrolytic silica, which can be surface-treated for use in the embodiments provided herein, are commercially available. Non-limiting examples of pyrolytic silica include CAB-O-SIL pyrolytic silica available from Cabot Corporation, HDK pyrolytic silica products available from Wacker Chemie AG, and AEROSIL pyrolytic silica available from Evonik Industries, Essen, Germany.

[0034] Alternatively or additionally, silica-containing grape-like particles containing other materials may be used. For example, silica-coated carbon black may be used. Exemplary silica-coated carbon blacks include those described in US6541113, US6197274, and US9598560, the contents of which are incorporated herein by reference. Silicon-treated carbon black having both a silica phase and a carbon phase may also be used. Methods for preparing and surface-treating various types of silicon-treated carbon black 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 discussed in US10800925, the entire contents of which are incorporated herein by reference, may also be used. Co-pyrolytic silica particles, such as silica-titanium dioxide or silica-alumina mixed oxides, may also be used. Exemplary hydrophilic and hydrophobic mixed oxides are disclosed in US5424258, US6197469, US7083769, US20100016490, US20050239921, US6328944, US4297143, and US7897256, the entire contents of which are incorporated herein by reference. Any of these non-hydrophobic silica-containing materials can be surface-treated in the same manner as pyrolytic silica or precipitated silica as described below.

[0035] In some embodiments, grape-like particles containing hydrophobic silica can be produced by treating hydrophilic granular silica (e.g., pyrolytic 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 be covalently bonded to the surface of the silica particles or can be present as a non-covalently bonded coating. Typically, the silica treatment agent is covalently or non-covalently bonded to the silica. In many cases, the silica treatment agent can be a hydrophobic silane or silazane or other silica treatment agent, for example, those known in the art.

[0036] In some embodiments, the silica treatment agent comprises a hydrophobic silane. For example, the silica treatment agent may be a compound of the following formula: R 4-n SiX n Where n is 1-3, each R is independently selected from hydrogen, C1-C30 branched or straight-chain alkyl or alkenyl, C3-C18 haloalkyl, C3-C10 cycloalkyl, and C6-C14 aromatic groups, preferably C1-C4 branched or straight-chain alkyl or alkenyl, and each X is independently C1-C18 branched or straight-chain alkoxy or halogen, wherein no more than three groups R are hydrogen. In some embodiments, the silica treatment agent comprises hydrophobic silazane, for example, the silica treatment agent may be hexamethyldisilazane or octamethyltrisilazane. Preferred hydrophobic treatment agents for use as grape-like particles containing hydrophobic silica in various embodiments herein include hexamethyldisilazane, alkyltrialkoxysilanes and alkyldialkoxysilanes such as hexamethyldisilazane and dimethyldichlorosilane.

[0037] Hydrophilic, silica-containing, grape-like particles can be surface-treated using any suitable method known to those skilled in the art. Dry silica particles can be surface-treated using wet or dry techniques known to those skilled in the art. For example, a dry treatment method may include stirring or mixing a metal oxide and a hydrophobic agent in a fluidized bed reactor. Alternatively, a wet treatment method may include dispersing the metal oxide in a solvent to form a metal oxide slurry and adding a hydrophobic agent to the slurry, thereby modifying the metal oxide surface with the hydrophobic agent. In a preferred embodiment, the mixture is then held at a temperature sufficient to alter the surface properties of the metal oxide for a period of time.

[0038] In addition to aerogels and grape-like particles containing hydrophobic silica, the compositions and / or heat control articles described herein further include one or more other ingredients. In many cases, these ingredients or components are selected to impart specific functions and / or properties to the final product (e.g., a blanket). In some cases, the type and / or amount of the added ingredient is chosen to achieve a balance or trade-off between the desired and less desirable contributions the ingredient may make to the final product. Manufacturing parameters, the end application, or other factors may be considered when selecting the type and / or amount of the ingredient to be used.

[0039] Among the components that can affect the properties of the finished product when added to silica-containing grape-like granules are fibrous materials. The fibrous material may be present in amounts ranging from 5% to 70% by weight, for example, 10% to 55% by weight, 15% to 45% by weight, 20% to 35% by weight, or 10% to 30% by weight, relative to the total weight of the silica-containing granular composition or heat-controlled article. Specific embodiments utilize fibrous components comprising heat-resistant inorganic fibers and / or polymeric fibers. Exemplary inorganic fibers include ceramic wool, ceramic fibers, and glass fibers. Examples of polymeric fibers include polybenzimidazole (PBI), aramid (aramid), or any combination thereof.

[0040] Ceramic fibers are typically made through a stretching process and then cut to the desired length, while ceramic "wool" (or other types of wool, such as mineral wool, sometimes also called "stone" wool) is usually made by spinning a melt. Generally, wools tend to have longer, more entangled fibers. Individually, wool fibers may not be stronger than shorter ceramic fibers (made through stretching and stubble cutting). However, in bulk, wools can have an additive effect that can improve the mechanical integrity of compositions and / or heat-controlled articles.

[0041] In many cases, the diameter of cotton fibers ranges from about 1 micrometer (μm) to several hundred micrometers. The fiber length can range from about 100 μm to several hundred μm or longer, sometimes several hundred millimeters (mm) long.

[0042] These high aspect ratio cottons also improve drainage and retention in wet-laid products because they provide additional surface area for well-dispersed active materials to aggregate during coagulation. This reduces the amount of active material removed along with excess process water during the forming process.

[0043] The amount of ceramic wool that can be used will generally depend on the desired properties (e.g., tensile strength, tear resistance, impact resistance), intended use, and / or other factors. Ceramic wool can be provided in amounts ranging from 0.5% to 100% by weight (relative to the weight of the fibrous component used to prepare the composition). In exemplary instances, it is present in amounts from about 5% to about 30% by weight. For example, it can be present in the fibrous component in amounts from about 10% to about 20% by weight.

[0044] Ceramic cotton may be present in the final product in an amount ranging from 0.25% to 4% by weight relative to the finished product (e.g., blanket), for example, from about 0.5 to about 2% by weight, for example, in the range of about 0.5 to about 1.0; about 0.5 to about 1.5; about 0.5 to about 2.0% by weight; or in the range of about 1.0 to about 1.5; about 1.0 to about 2% by weight; or about 1.5 to about 2.0% by weight.

[0045] Suitable ceramic wool includes aluminum (provided as Al2O3), silicon (in the form of SiO2), and iron (in the form of Fe2O3), or any combination thereof. In addition to or in place of any of these components, some ceramic wool may also include titanium dioxide (TiO2).

[0046] While not an essential element, the presence of zirconium can provide mechanical benefits and / or contribute to the temperature resistance of the final silica-containing particulate composition and / or heat control articles (e.g., blankets). In some implementations, zirconium (typically in the form of zirconium oxide (ZrO2)) is provided in zirconium-containing cotton, which may also include other elements such as aluminum, silicon, iron, and / or titanium. Commercially, Ceramaterials (Dingmans Ferry, PA) offers two types of spun fibers, one with a higher zirconium oxide concentration (with temperature resistance up to 2600℉ / 1400℃) and one with a lower zirconium oxide loading (2300℉ / 1400℃).

[0047] In finished products, blankets (such as ceramic wool) can be identified through analytical techniques, such as high-resolution microscopic examination of a uniform cross-section of a sample product (e.g., a blanket). It is believed that ceramic wool will retain a different structure compared to chopped ceramic fibers, even after processing. Other applicable techniques include scanning electron microscopy (SEM) (often abbreviated as "SEM / EDX") using energy-dispersive X-ray (EDX) capabilities to correlate typical concentrations of elements with ceramic wool to distinguish it from other types of fibers.

[0048] Another type of wool that can be used to prepare the compositions described herein is mineral wool (also referred to in some cases as "stone" wool). Mineral wool is commercially available from Rockwool A / S under the trade name "Rockwool®" mineral wool, from Knauf Insulation (Shelbyville, IN, USA), and from other suppliers. The amount of mineral wool can be the same as or similar to that used in the case of ceramic wool. However, other ranges can be used.

[0049] Mineral wool can be identified in finished products (such as blankets) using techniques such as scanning electron microscopy (SEM) (often abbreviated as "SEM / EDX") which uses energy-dispersive X-ray (EDX) capabilities, associating typical concentrations of elements with mineral wool to distinguish it from other types of fibers.

[0050] In some embodiments, the compositions described herein comprise various forms of heat-resistant polymeric materials. Some approaches utilize aramid fibers that can be defined as “pulp” (between 0.1-6 mm) or chopped fibers (>6 mm). Chopped aramid fibers and pulp are widely available, with DuPont (trademarked Kevlar®) being a major global manufacturer. Optionally or additionally, longer aramid fibers cut to lengths such as 3 mm, 6 mm, or 12 mm may also be used.

[0051] Other methods utilize polybenzimidazole (PBI) fibers, which are typically characterized by excellent heat and chemical resistance. Because PBI fibers have no identifiable melting point, they will not ignite or drip when exposed to high temperatures. PBI fibers are available from PBI Performance Products (Charlotte, NC). PBI fibers can be at least 0.1 mm in length, for example, 0.5 to 10 mm, 1-8 mm, or 2-6 mm.

[0052] Materials such as aramid or PBI fibers are considered particularly suitable for addressing the expansion and contraction observed in battery packaging during charging or discharging under hot or cold conditions. Allowing the battery encasement to expand reduces stress on the battery compartment, minimizing wear and tear on battery materials.

[0053] While still imparting these advantageous properties, these polymeric fibers are typically used in the lowest possible amounts because adding them could impair the desired low flammability rating of the finished product (e.g., blankets).

[0054] PBI and / or aramid fibers may be provided in an amount of about 0.5 to 100% by weight (relative to the weight of the fibrous component used to prepare the composition). In illustrative examples, they are present in an amount ranging from about 5 to about 30% by weight or from 25% to 80%. For example, they may be present in the fibrous component in an amount of about 10 to about 20% by weight.

[0055] In many cases, the amount of fibers such as aramid or PBI is 0.25% to 4% (based on the weight of the silica-containing particulate composition or heat-controlled article), for example, from about 0.5% to about 2% by weight, such as, for example, in the range of about 0.5% to about 1.0% by weight; about 0.5% to about 1.5% by weight; about 0.5% to about 2.0% by weight; or in the range of about 1.0% to about 1.5% by weight; about 1.0% to about 2% by weight; or about 1.5% to about 2.0% by weight.

[0056] In finished products (such as blankets), aramid or PBI fibers can be identified using techniques such as SEM / EDX, thus distinguishing the polymeric structure from the surrounding inorganic environment.

[0057] Ceramic fibers are known for their excellent oxidation resistance and corrosion resistance at high temperatures. Typically, ceramic fibers are characterized by a polycrystalline (rather than amorphous) structure. Some (e.g., refractory ceramic fibers) are particularly suitable as thermal insulation materials for high-temperature applications. In some embodiments, ceramic fibers represent the main component (greater than 50% by weight relative to the total weight of the fibrous component).

[0058] Suitable chopped ceramic fibers that can be used in the compositions described herein include one or more (two, three, four or more) inorganic oxides, such as Al₂O₃, B₂O₃, Na₂O, K₂O, CaO, and MgO. Some fibers may also include silicon oxides. Many types of ceramic fibers (generally well characterized in terms of composition, length, and / or other properties) are commercially available. Suitable chopped ceramic fibers include, but are not limited to, fibers from Unifrax's 7000 and 6000 series. In one example, the ceramic fiber is a coarsely chopped, high-purity alumina-silica product from Unifrax. Ceramic fibers can have various diameters, such as 1.5-2.5 micrometers, and can be cut to specific lengths or obtained at non-uniform lengths, including shots (unfiberized material) mixed with longer fibers. In some embodiments, the collection of ceramic fibers may contain up to 45-55% shots. For the purposes of this disclosure, when shots are present, they are still considered as part of the fibrous material in the silica-containing particulate composition or thermal control components.

[0059] Alternatively or additionally, glass fibers or other fibers may be used alone or in combination with one or more of the aforementioned ceramic fibers and / or ceramic wool, aramid fibers and / or PBI fibers. Illustrative glass fibers include: borosilicate (B fibers), acid-resistant borosilicate (C fibers), and calcium aluminum borosilicate (E fibers), which may be obtained, for example, from LauschaFiber International or Unifrax, including CM-210 glass microfibers; and / or fibers composed essentially of silica (Q fibers), which may be obtained, for example, from Johns Manville. Glass fibers may be cut into various lengths, such as 3 mm, 6 mm, or 12 mm, or may be used as “granules.” Glass fibers may have various diameters from 0.25 micrometers to 12 micrometers, such as 0.25 micrometers to 0.5 micrometers, 0.5 to 1.5 micrometers, 1.5 to 2.5 micrometers, 1 micrometer to 5 micrometers, or 8 micrometers to 12 micrometers, such as 6, 9, or 12 micrometers. Alternatively or additionally, more than one type of glass fiber may be used, for example, cut into more than one length or diameter, such as a blend of fibers with a diameter less than 1 micrometer and fibers with a diameter greater than 5 micrometers. Silica gel fibers are produced by spinning gelled silica sol, for example, as described in US20200308729, the entire contents of which are incorporated herein by reference.

[0060] Other fibers that can be added to ceramic fibers, glass fibers, ceramic cotton and / or polymeric fibers (such as PBI or aramid) include non-ceramic fibers such as cellulose, cotton, carbon, acrylics, polyvinyl alcohol (PVA), phenolic resins, polyolefins and / or other types of fibers, and mixtures of such fibers.

[0061] The fibers used can have any structure known to those skilled in the art. For example, the fibers can be in the form of chopped fibers, microfibers, woven fibers, or nonwoven fibers.

[0062] The cross-sectional shape of the fiber can be circular, polygonal, trilobal, pentalobal, octlobal, strip-shaped, fir-shaped, dumbbell-shaped, or other shapes. The fiber can have a uniform or varying diameter along its length. Hollow fibers can be used in some embodiments. Additionally, the fiber material can be smooth or wrinkled, and can be crimped or straight.

[0063] In some implementations, coated fibers are used. Polyester fibers metallized with metals such as aluminum are one example.

[0064] Fibers modified with additives are also suitable. Examples of such additives include, but are not limited to: antistatic agents, such as carbon black; and / or IR-blocking agents (typically used to reduce the contribution of radiation to thermal conductivity), such as carbon black, titanium dioxide, alumina, iron oxide, or zirconium dioxide, silicon carbide, or any mixture thereof.

[0065] In addition to including IR-blocking agents, the contribution of radiation to thermal conductivity can be further reduced by using blackened fibers, such as polyester fibers blackened with carbon black or simply carbon fibers.

[0066] The amount of the fibrous component (a fiber or a blend of fibers) used depends on its density, diameter, length, etc., and can be from 1% to 99% by weight, preferably from 5% to 55% by weight, for example 10% to 50% by weight, 15% to 40% by weight, 20% to 35% by weight, or 10% to 30% by weight. This is relative to the weight of the silica-containing particulate composition and / or the heat-controlled article. In certain embodiments, the mass ratio of the silica-containing particulate component (total aerogel + grape-like particles containing hydrophobic silica) to the fibrous component is in the range of 1:10 to 10:1, preferably 1:3 to 10:1 (by weight), for example 1:2 to 10:1, 1:3 to 3:1, 1:2 to 2:1, 1:1 to 10:1, 1.2:1 to 9:1, 1:2 to 9:1, or 1:1 to 5:1. When the relative amount of the fibrous component is too large, the thermal conductivity of the silica-containing particulate composition and / or heat-controlled article may be too high. When the relative amount of the fibrous component is too small, the tensile strength of the silica-containing particulate composition and / or heat-controlled article may be too low.

[0067] Blends of fibers can also be used. For example, a first fiber selected to provide mechanical strength can be used in combination with a second fiber used to retain silica-containing particles and other particulate matter such as opacifiers within the blanket. The first fiber is typically glass or ceramic fiber, while the second fiber is typically a fiber with a high aspect ratio, but can be a longer glass or ceramic fiber. Optionally or additionally, a third fiber can be included to enhance specific mechanical properties. For example, adding a polymer fiber as a third fiber can enhance the flexibility of the resulting composition or heat-controlled article.

[0068] While the wools and / or heat-resistant polymeric fibers described herein may represent all fibrous components in the composition, they are often used in combination with glass or ceramic fibers. In many cases, glass or ceramic fibers may actually represent the primary fibrous component (greater than 50% by weight relative to the total weight of the fibrous component) and may be considered the "primary" fiber used in the composition. In such cases, the term "secondary" may be applied to ceramic wools and / or heat-resistant polymeric fibers (e.g., PBI, aramid) in the composition. Alternatively, PBI or aramid fibers may represent the primary fibrous component. Blends of glass and ceramic fibers may also be used (e.g., ceramic or glass as the primary fiber and the other as the secondary fiber), and generally, any fiber or wool disclosed herein may be combined with one or more other fibers or wools. In some embodiments, the weight ratio of primary to secondary fibers is 100:1 to 1:100, for example, 50:1 to 1:50, 35:1 to 1:35, 25:1 to 1:25, 15:1 to 1:15, 10:1 to 1:10, 7:1 to 1:7, 5:1 to 1:5, 4:1 to 1:4, 3:1 to 1:3, or 2:1 to 1:2. In certain embodiments, glass fibers or ceramic fibers are used alone, or in a weight ratio of 1:4 to 10:1 with aramid fibers, for example, 1:3 to 5:1, 1:2 to 3:1, or 1:1 to 2:1. Optionally or additionally, different types of glass fibers, such as glass fibers with a diameter of 5 to 10 micrometers, are used in combination with glass microfibers with a diameter of less than 1 micrometer in a weight ratio (larger diameter: smaller diameter) of 5:1 to 1:5, for example 4:1 to 1:4, 2:1 to 1:2, or 1:5 to 1 to 1:1.5. Optionally or additionally, ceramic microfibers are the primary fibers, and glass fibers or microfibers are secondary fibers. Optionally or additionally, combinations of three or more types of fibers are used, for example, ceramic microfibers (with a diameter of less than 5 micrometers or less than 3 micrometers) are used in combination with two or more of the following: glass fibers with a diameter of 5-10 micrometers, glass fibers with a diameter of less than 5 micrometers or less than 1 micrometer, aramid fibers, and PBI fibers. Optionally or additionally, glass fibers used to manufacture silica-containing particulate compositions or thermal control components are chopped to 6 micrometers or less or 3 micrometers or less.

[0069] The length and diameter of fibers (such as glass fibers or ceramic fibers) can vary depending on the specific application. For example, finer fibers, such as microfibers (with a diameter of less than 5 micrometers or less than 1 micrometer), can increase flexibility, while the length and / or distribution of fibers can play a role in increasing the mechanical strength of the final product (such as a blanket). In illustrative examples, fibers are cut into lengths of 3 mm, 6 mm, or 12 mm, or other commercially available lengths. Two or more different types of fibers, or fibers made of the same material but characterized by different fiber lengths, length distributions, diameters, or diameter distributions, can be used to obtain bimodal or multimodal length or diameter distributions of the fibers.

[0070] In some embodiments, the composition and / or heat-controlled article comprises elastomeric particles, such as silicone particles, rubber powder, or thermoplastic microspheres. Such materials are considered to potentially improve both the reinforcement and elasticity of the finished product (e.g., a blanket). The elastomeric particles can be solid, hollow, and / or resin-coated. For the purposes of this specification, elastomeric powders or particles are classified together with other particulate components of the composition, such as opacifiers, but not with polymeric components such as dispersants, surfactants, flocculants, defoamers, and binders.

[0071] Silicone powders or granules of various average particle sizes (avg PS) (e.g., diameters ranging from approximately 1 micrometer to 1 mm) are commercially available. As an example, suppliers such as Shin Etsu Silicones offer suitable elastic particles with their Silicon Powder KMP series. For instance, particles with an average PS of 13 μm are available under product code KMP-598, while product KMP-402 offers PS=30 μm.

[0072] In many embodiments, the compositions described herein include a light-blocking agent, such as an infrared (IR) light-blocking agent, to reduce radiative heat transfer. These materials reduce the transmission of infrared radiation and may include, for example, carbon black, mica, alumina, graphite, titanium dioxide, rutile sand, iron oxide, silicon carbide (SiC), graphite, or zirconium dioxide. Some suitable types of titanium dioxide include, for example, Tipure® (DuPont) and Altiris® (Huntsman). IR light-blocking agents can be used alone or as a mixture of two or more compounds. The particle size can be selected to reflect specific wavelengths. For example, for ceramic light-blocking agents such as titanium dioxide, particles smaller than 1 micrometer, as measured by laser diffraction, can more effectively block visible light (compared to IR radiation), while the thermal conductivity of the particles can be increased at larger particle sizes (e.g., greater than 3 micrometers). In another example, silicon carbide can be obtained in grit sizes from F230 to F2000, such as F500, F600, F800, F1000, F1200 and F1500 (Federation of European Producers of Adhesives).

[0073] An IR-blocking agent can be added in selectable amounts to provide a target level of IR transmission reduction in silica-containing particulate compositions and / or thermal control articles (e.g., blankets). Exemplary levels, based on the total mass of the silica-containing particulate composition and / or thermal control article, may be, for example, up to 10%, 0.5% to 8%, 0.75% to 5%, or 1% to 3% of the IR-blocking agent. Adding IR-blocking agents characterized by two or more different average particle sizes to a given composition can extend the range of IR wavelengths covered.

[0074] In some embodiments, the silica-containing particulate composition and / or heat control articles (e.g., blankets) may include a fire retardant or flame retardant. The fire retardant may be, for example, an alkali metal oxide, an alkaline earth metal oxide, aluminum trihydrate, magnesium hydroxide, antimony oxide, titanium dioxide, rutile sand, melamine compounds, phosphate-based compounds, or halogen-based compounds. In certain embodiments, the titanium dioxide particles may 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 as measured by laser diffraction, and in some embodiments, the particle size distribution may have a d50 of about 1.0 μm + / - 0.01 μm, + / - 0.02 μm, or + / - 0.05 μm. Halogenated fire retardants include, for example, brominated fire retardants (BFRs), such as organic bromide compounds comprising polymeric organic bromide compounds. In another set of embodiments, the polymeric fire retardant has a structure with a high ratio of heteroatoms to carbon atoms. For example, in some embodiments, the ratio of heteroatoms to carbon atoms may be greater than 0.5:1, greater than 1:1, or greater than 2:1, and in certain embodiments, the heteroatoms may be nitrogen and / or sulfur. The fire retardant and / or flame retardant may be incorporated into the silica-containing particulate composition and / or heat control article at concentrations sufficient to suppress flammability or meet specifications such as UL94-V0. Optionally or additionally, exemplary silica-containing particulate compositions and / or heat control articles may exhibit, 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, such as 0.5 MJ / kg or 1 MJ / kg to 5 MJ / kg caloric content.

[0075] The concentration of the fire retardant and / or flame repellent that can be used may be in the range of 0.1% to 5.0% by weight, 0.2% to 2.0% by weight, and 0.3% to 1.5% by weight relative to the mass of the silica-containing particulate composition and / or heat control article. In a particular embodiment, the fire retardant or flame repellent is combined with silica-containing particles, for example, with a mixture containing botryoidal particles containing silica and optionally aerogel particles.

[0076] Endothermic materials or phase change materials can also be used. Such materials help silica-containing particulate compositions and / or heat control articles (e.g., blankets) to act not only as insulators that impede heat transfer but also as heat reservoirs that can store thermal energy. Such endothermic materials may include aluminum hydroxide and other materials known to those skilled in the art. Alternatively or additionally, endothermic materials may include phase change materials that store heat by undergoing a thermodynamic phase change or a change in hydration state or crystal structure. Suitable phase change materials include both organic and inorganic materials, such as metals, inorganic salts, and inorganic hydrated salts. The endothermic material may be combined with silica-containing particles, or it may be deposited on the surface of a silica aerogel used in a silica-containing particulate composition or otherwise impregnated into the pores of the silica aerogel.

[0077] The composition may optionally include an adhesive. In some cases, the adhesive may help prevent the widespread dispersion or loss of silica aerogels, grape-like particles containing hydrophobic silica, and / or silica-containing particulate compositions and / or other particulate components of thermal control articles, in case of catastrophic failure or explosion of the isolated item (e.g., a battery). Examples of suitable adhesives include, but are not limited to, silicones, polyurethanes, epoxy resins, polyvinyl alcohol, polyvinylidene fluoride, polyethylene terephthalate, polybutylene terephthalate, acrylate (acrylic) polymers, etc. Adhesives comprising heat-resistant and / or fire-retardant polymers are preferred. Adhesives such as polyvinyl alcohol, silicones, polyurethanes, styrene-butadiene polymers, or acrylate or acrylic polymers may also bind additives such as carbon black to silica-containing particles to reduce dust during downstream processing of silica-containing particulate compositions. Exemplary commercially available adhesives include Joncryl FLX5201, FLX5220, FLX5026A, and 1670 polymers from BASF; U4000, U4101, and APU 10120 polymers from Alberdingk Boley; Novacryl PSR300 polymer from Synthomer; and Styrofan 4306 polymer from BASF. The adhesive can 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 apparatus known to those skilled in the art. Preferably, the adhesive does not render the silica-containing particulate composition flammable under UL94 or other flammability testing methods.

[0078] Processing aids may also be included. The selected processing aids will depend on the manufacturing method and form of the silica-containing particulate composition and / or heat-controlled article. Suitable processing aids include, but are not limited to, defoamers, surfactants, dispersants, and emulsifiers.

[0079] Various commercial defoamers are known to those skilled in the art and are suitable for use with the silica-containing particulate compositions described herein. The defoamer may be a polyol or polyglycol, for example, available under the name Surfynol from Evonik Industries. Alternative polyols include, but are not limited to, 1,3-propanediol, 1,2-butanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, glycerol, trimethylolpropane, pentaerythritol, triethanolamine, and trimethylolaminomethane. Alternatively or additionally, oil-based or fatty acid-based defoamers may be used. Alternatively or additionally, the defoamer may be a polymer-based defoamer, such as a silicone-based defoamer, such as Dehydran 1293 from BASF.

[0080] Dispersants or surfactants can be selected from, for example, ionic (anionic and cationic) surfactants and dispersants, amphoteric surfactants and dispersants, nonionic surfactants and dispersants, and high molecular weight surfactants and dispersants. Suitable anionic surfactants include alkyl sulfates and higher alkyl ether sulfates, more specifically, such as ammonium lauryl sulfate and sodium polyoxyethylene lauryl ether sulfate. Suitable cationic surfactants include aliphatic ammonium salts and amine salts, more specifically, such as alkyl trimethylammonium and polyoxyethylene alkylamine. Amphoteric surfactants can be betaine-type, such as alkyl dimethyl betaine, or oxide-type, such as alkyl dimethyl amine oxide.

[0081] Suitable nonionic dispersants include, for example, glycerol fatty acid esters, propylene glycol fatty acid esters, sorbitol fatty acid esters, polyoxyethylene sorbitol fatty acid esters, tetraoleic polyoxyethylene sorbitol, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxypropylene alkyl ethers, polyethylene glycol fatty acid esters, higher fatty acid alcohol esters, polyol fatty acid esters, polyether-modified polydimethylsiloxanes, etc.

[0082] Other potential surfactants include AEROSOL OT (sodium di-2-ethylhexyl sulfosuccinate), BARLOX 12 (branched alkyl dimethyl amine oxide), BARLOX 12i (branched alkyl dimethyl amine oxide), TRITON 100 (octylphenoxy polyethoxy(9-10) ethanol), TWEEN surfactants such as TWEEN 100 surfactant, and BASF Pluronic surfactant. Other examples of wetting agents include glycols, alkoxylated polyoxyethylene fatty ethers, such as polyoxyethylene fatty ethers, sorbitol esters, monoglycerides and diglycerides, polyoxyethylene sorbitol esters, polymeric surfactants such as Hypermen polymeric surfactants, sodium coco-PG-dimonium chloride phosphate and cocamidopropyl PG-dimonium chloride ester, phosphate esters, polyoxyethylene (POE) fatty acid esters, Renex nonionic surfactants (nonionic esters formed by the reaction of ethylene oxide with unsaturated fatty acids and heterocyclic resin acids), alcohol ethoxylates, alcohol alkoxylates, ethylene oxide / propylene oxide block copolymers, polyoxyethylene derivatives of sorbitol esters, or combinations thereof. The preferred dispersant has at least one cationic or cationic group and an HLB ratio of 2 to 20, more preferably an oligomer of ethylene oxide and propylene oxide in a molar ratio of ethylene oxide segments (mers) to propylene oxide segments of 0.1:1 to 11:1. Exemplary dispersants include, but are not limited to, Jeffamine M-2070 (Huntsman) (a monofunctional primary amine with a weight-average molecular weight of about 2,000, a propylene oxide / ethylene oxide (EO / PO) molar ratio of 31 / 10, and an HLB value of 13.8), Jeffamine M600 (Huntsman) (a monofunctional primary amine with a weight-average molecular weight of about 600, a propylene oxide / ethylene oxide (EO / PO) molar ratio of 1 / 9, and an HLB value of 2), Jeffamine ED900 (Huntsman) (a bifunctional primary amine with an EO / PO ratio just greater than 2 and a weight-average molecular weight of about 900), Surfonamine L-300 (Huntsman) (a monofunctional primary amine with an EO / PO ratio of about 58 / 8, a weight-average molecular weight of about 3,000, and an HLB value of about 17.1), and Surfonamine B-200 compound (a monofunctional primary amine with an EO / PO ratio of about 6 / 29 and a weight-average molecular weight of about 2000).

[0083] While components can be combined in any suitable manner in many cases, the techniques used to combine some components can benefit from additional considerations. For example, with fibers, too little mixing energy can result in undispersed fiber bundles that do not effectively improve performance. On the other hand, over-dispersion (at unrestricted mixing lengths or energies) can lead to self-entanglement and “balling.” Excessive chopping and cutting energy can cause fiber lengths to decrease to less than ideal, thus affecting product properties or performance. As for equipment, mixing operations relying on cutting blades with sharp leading edges have been found to also contribute to fiber length reduction. While this may be relatively benign on short timescales, the effect is expected to accelerate over longer periods.

[0084] It was also found that certain properties of the materials being bonded can make them more susceptible to the "overprocessing" effect. For example, in the case of fibers, this effect becomes more pronounced for fiber lengths greater than approximately 6 mm (0.25 inches) and / or for fine coarseness.

[0085] Therefore, some of the implementations described herein involve controlling mixing parameters such as mixing time, supplied energy, and the type of equipment, such as blade type. In specific examples, the mixing parameters take into account the properties of the material being processed. In other cases, the properties of the material are evaluated and then correlated with suitable mixing parameters. Establishing suitable mixing parameters can be based on routine experiments, prior experience, etc.

[0086] To form the compositions described herein, the components can be combined in any suitable manner and may involve a single step. However, in many cases, mixing is performed sequentially in two or more steps using equipment known in the art. In one example, silica-containing particles and fibers are added to a solution containing processing aids such as defoamers, surfactants, dispersants, and / or emulsifiers.

[0087] In some embodiments, the mixture is encapsulated in an encapsulation. The encapsulation can serve to prevent dust accumulation, help maintain the shape of the thermal control component, facilitate the manipulation or installation of the thermal control component, and / or provide other useful functions known to those skilled in the art. The material forming the encapsulation is preferably a fire-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. Optionally or additionally, the material used for the encapsulation may include reinforcing fibers, such as aramid fibers, to provide puncture resistance. The reinforcing material may be used in combination with other polymers, or the encapsulation may be formed entirely of such polymers, such as a woven fabric of aramid fibers.

[0088] Heat control articles may be made in any form known to those skilled in the art. For example, silica-containing particulate compositions (e.g., fiber-containing blankets or mats) may be prepared using techniques described, for example, in US9399864, US20210363699, WO2022024085, CN112759353, US11274044, CN112681009, CN113943171, CN110093783, CN112681009, JP2015048543 and / or US20200295328, the contents of all of which are incorporated herein by reference.

[0089] Typically, in a wet web forming process, silica-containing particles and optional materials are flocculated from an aqueous slurry to form a substantially stable, homogeneous particle suspension (flocculation). Preferably, the aqueous slurry includes less than 5% by weight of an organic solvent, such as less than 3% by weight or less than 1% by weight. The flocculent can be separated from the aqueous solvent, forming a two-phase system consisting of flocculated particles floating above a substantially water-based supernatant. The flocculent can float on top of the supernatant, or a portion of the flocculent can be suspended in the supernatant. The flocculated material can support a uniform distribution of different particles that can be formed into a blanket. This stable, consistent distribution of particles can provide a blanket exhibiting a uniform composition overall.

[0090] In one embodiment, such as that described in US9399864, an aqueous slurry is prepared from a mixture of silica aerogel, hydrophobic silica-containing particles, ceramic fibers, and other components (e.g., binders, opacifiers, flame retardants, defoamers, etc.). Preferably, the relative amounts of the various components in the aqueous slurry correspond to their relative amounts in the silica-containing particle composition. A charged compound or other emulsifier or dispersant is included in the slurry to generate an emulsion, which is then coagulated with a flocculant. The resulting flocculent is collected on a scrim or belt and dehydrated. The thickness of the silica-containing particle composition can be adjusted by increasing or decreasing the solids loading of the aqueous slurry. In some embodiments, the solids loading can be from 5% to 25% by weight of the aqueous slurry, for example, 5% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, or 20% to 25% by weight.

[0091] Unbound by any particular theory, it is believed that as flocculation becomes more effective, various particles can be more densely packed within the blanket. The flocculant preferably flocculates enough solids in the mixture that most of the solids float to the top of the aqueous mixture, resulting in a relatively clear, rather than turbid, aqueous medium. Preferred flocculants are polymeric flocculants compared to inorganic flocculants. Exemplary polymeric flocculants include quaternary polyamines, such as polyamines like SuperFloc® 577 or 581 flocculants from Kemira, and polyacrylamides such as Nalclear 7768, Nalclear 8187, and Nalclear 8176 polymers from Nalco, dicyandiamide resins, polydiallyl dimethyl ammonium chloride (PDADMAC), aminosilanes, quaternary amine-functionalized silanes, silicone resins, and any mixtures or emulsions of these. In some embodiments, the flocculant is in the form of an aqueous emulsion or latex of the flocculant. The flocculant may have various number-average molecular weights, such as 400 to 60,000,000, preferably 400 to 1,000,000, such as 5,000 to 10,000, 10,000 to 100,000, 100,000 to 500,000, 500,000 to 1,000,000, 20,000 to 10,000,000, 1,000,000 to 30,000,000, or 5,000,000 to 50,000,000.

[0092] Flocculants can be used in combination with flocculants. The flocculant is preferably an ionic polymer; the flocculant is preferably an ionic polymer with opposite charges. In some embodiments, the flocculant is in the form of an aqueous emulsion or latex. The number-average molecular weight of the flocculant can be from 400 to 1,000,000, for example, 5,000 to 10,000, 10,000 to 500,000, 20,000 to 50,000, or 50,000 to 1,000,000. Alternatively, the molecular weight of the flocculant can be within the ranges described above for the flocculant. Suitable flocculants include, but are not limited to, natural and synthetic latex polymers, acrylics, and polyacrylamides. Since the flocculant is preferably a charged polymer, any of the reagents listed above as flocculants can also be used as a flocculant, depending on the relative charge. Crucially, only one component of the flocculation system (here referred to as the flocculant polymer) is added to the aqueous slurry before or simultaneously with the addition of other components (particles, fibers, opacifiers, etc.), while the flocculant agent is added only after all other components have been combined. Preferably, the amounts of the flocculant agent and the flocculant polymer are such that the deviation between the charge provided by the flocculant agent (i.e., charge density multiplied by mass) and the charge provided by the flocculant polymer does not exceed 20%, for example, a deviation of no more than 10%, no more than 5%, or no more than 1%.

[0093] The total amount of flocculant and flocculant polymer together should be sufficient to bind the various components of the silica-containing particulate composition, but not so large that they fill the pores of the silica-containing particulate composition, thereby reducing thermal conductivity. In practice, in some embodiments, the flocculant and flocculant polymer can provide all the necessary binding properties in the silica-containing particulate composition, thus avoiding the use of adhesives. Using more than necessary amounts of flocculant and flocculant polymer may also undesirably affect the mechanical properties of the composition, undesirably increase density, increase the heat content of the silica-containing particulate composition, or reduce flammability. The total weight fraction of polymers (including dispersants, binders, defoamers, flocculants, and flocculants) used to produce the silica-containing particulate composition can be less than 25% by weight, for example, 3 to 25% by weight, for example, 4% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, or 20% to 25% by weight, based on the total weight of the substances added to the aqueous solvent (i.e., the total weight of the flocculants and supernatant, but excluding the aqueous solvent). Without the use of binders, this amount can be even smaller, for example, 3% to 15% by weight or 8% to 17% by weight based on the total weight of the substances added to the aqueous solvent to form the silica-containing particulate composition. The same proportion of polymer can be found in the resulting silica-containing particulate composition. Similarly, the total weight of polymers (including dispersants, binders, defoamers, flocculants, and flocculants) in the resulting silica-containing particulate composition can be less than 25% by weight based on the total weight of the silica-containing particulate composition, for example, 3 to 25% by weight, for example, 4% to 10% by weight, 10% to 15% by weight, 15% to 20% by weight, or 20% to 25% by weight. Without the use of binders, this amount can be even smaller, for example, 3% to 15% by weight or 8% to 17% by weight based on the total weight of the silica-containing particulate composition.

[0094] A threshold amount of dispersant, defoamer, flocculant, and flocculant polymer is required to form a cohesive silica-containing particulate composition using a wet web-forming method. Those skilled in the art will recognize that the required amounts will vary depending on the relative amounts of the non-polymer components (particles, fibers, opacifiers, flame retardants, heat-absorbing materials, etc.). However, excessive amounts of these substances may be detrimental to thermal conductivity and / or flame retardancy according to UL-94 and may undesirably increase density. In some embodiments, the total amount of the flocculation system (i.e., flocculant and flocculant polymer) and binder used to prepare the silica-containing particulate composition or heat-controlled article is 3-20% by weight, for example, 4-16% by weight, based on the total weight of the flocculant and supernatant, excluding aqueous solvents. Similarly, the total amount of the flocculation system and binder in the silica-containing particulate composition may be 3-20% by weight, for example, 4-16% by weight, based on the total weight of the silica-containing particulate composition.

[0095] In some embodiments, the bulk density of the various components can be increased by pressing additional water out of the flocs before drying. For example, the flocs can be passed through a two-roll press or pressed between two plates or plates. Alternatively, a single roller can be passed over the flocs. Extrusion increases the bulk density of the various components by squeezing water out of the flocs. In the final product, this reduces interparticle porosity as the remaining water is replaced by air during drying. Optionally or additionally, any of these methods can be used to compress the silica-containing particulate composition after drying. After drying, compression can be used to make the composition thinner and denser, resulting in the silica-containing particulate composition and / or thermal control components occupying less space and also improving mechanical properties. The density of the silica-containing particulate composition or thermal control components can be 0.1 g / cm³. 3 Up to 0.6 g / cm 3 For example, 0.15 g / cm³ 3 up to 0.5 g / cm 3 0.15g / cm 3 Up to 0.4 g / cm 3 or 0.2g / cm 3 Up to 0.35 g / cm 3 .

[0096] In another embodiment, the aerogel, hydrophobic silica-containing grape-like particles, fibers, adhesive, and any other desired components are packed into a mold and pressed into a pad, for example, as described in EP3835262, the entire contents of which are incorporated herein by reference. Heating or otherwise activating the polymeric adhesive in the mold may be necessary. Alternatively or additionally, the aerogel, hydrophobic silica-containing grape-like particles, and other components can be formulated into a paste and extruded, for example, as described in EP3835262 and WO2020228998, the entire contents of which are incorporated herein by reference. Alternatively, the aerogel, hydrophobic silica-containing grape-like particles, and any other desired components can be used to fill encapsulations or other cavities using techniques such as those described in CN113785431, CN110544809, JP2012145204, and / or US20210332932, the contents of all of which are incorporated herein by reference. Alternatively or additionally, the mixture may be incorporated into or combined with polymer foams, as described in WO2020211320, JP2020019925 and US10640629.

[0097] Another suitable technique is to fill the mixture into an encapsulation or bag held in a mold at appropriate intervals. The mold is compressed by hand, for example using a clamp, and then preferably evacuated. For thinner encapsulations, it may be desirable to use a smaller diameter aerogel to facilitate free flow throughout the bag. Alternatively, the mass of material required to produce the desired mass density in an encapsulation or bag of a specific volume can be simply filled into the encapsulation without the use of a mold. The encapsulation can then be compressed with rollers to distribute the mixture evenly throughout the bag. In a preferred embodiment, a film or sheet, such as polyethylene terephthalate or silicone, is placed in a mold on a vibrating table, and the mixture is filled into a mold having a cavity in which a portion of the film or sheet overhangs. The mold is vibrated and compressed with a plate at 8-12 psi to compact the mixture. A top sheet (or film) large enough to cover the cavity and overhang is placed on top, and the overhang is sealed on three sides with the top sheet. Air is evacuated from the resulting encapsulation and the fourth side is sealed. In practice, certain components (such as fibers and adhesives) may not be necessary if the encapsulation provides the desired mechanical support. In fact, in some implementations, it may only be necessary to have aerogel and any optional light-blocking agents and / or particles containing hydrophobic silica in the encapsulation.

[0098] Thermal control articles (e.g., blankets) comprising a silica-containing particulate composition can be manufactured in a generally planar or flat form for insertion between cell units of a rechargeable battery (e.g., a lithium-ion battery). Alternatively, the article can be prepared into another desired shape. The evacuated encapsulation can be slightly thinner than the space in which it will be installed. Once installed, the encapsulation can be punctured to release the vacuum, and the encapsulation will expand until it is under compression. As the battery expands and contracts, the thermal control component will also freely expand and contract. Optionally or additionally, the encapsulation does not need to be manufactured as a flat or sheet-like object, but can be manufactured into a specific shape. For example, the thermal control article can be shaped to surround a specific component in a battery or other device and can have more complex shapes.

[0099] In some embodiments, the silica-containing particulate composition is formed to an appropriate size or cut to the desired size for the heat control article. Optionally or additionally, the heat control article includes additional sheet material to enhance mechanical integrity, heat resistance, mechanical resilience, and / or other properties. Examples include, but are not limited to, silicone-based materials, polyvinylidene fluoride, chlorinated polyethylene, aromatic polyamide materials such as Kevlar (e.g., woven felts of aromatic polyamide fibers), and Kevlar nanofiber aerogels such as Lyu, as described in ACS Nano 2019, 13, 2236-2245. Woven felts of Kevlar or other aromatic polyamide fibers may be impregnated with shear-thickening fluids (e.g., those described in US 7,825,045, the contents of which are incorporated herein by reference).

[0100] Encapsulations can be used in some cases to prevent dust generation, help maintain the shape of the heat control article, facilitate its handling or installation, etc. The material forming the encapsulation is preferably a fire-retardant and / or heat-resistant polymeric material, including, for example, silicone, polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), chlorinated polyethylene, and other similar polymers known to those skilled in the art. Optionally or additionally, the material used for the encapsulation may include reinforcing fibers, such as aramid fibers, to provide puncture resistance. The reinforcing material may be used in combination with other polymers, or the encapsulation may be formed entirely of such polymers, such as a woven fabric of aramid fibers. In one embodiment, the encapsulation may comprise one or two polymer films, such as PET films, disposed around two planar sides of the silica-containing particulate composition. In some embodiments, a frame, such as silicone rubber, may be disposed around the edges of the silica-containing particulate composition and the encapsulation to seal the encapsulation and facilitate handling of the resulting heat control article.

[0101] Alternatively or additionally, the thermal control article may comprise several layers of silica-containing particulate composition stacked one on top of the other. Optionally, the layers may be separated by any material described above in conjunction with the encapsulation. Alternatively or additionally, the layers may be separated by foam pads or mica sheets to further improve insulation properties. Alternatively or additionally, such layers may be used on the outer side of the silica-containing particulate composition laminate. In some embodiments, it may be desirable to include a thermally conductive material configured to transfer heat to, for example, a heat sink in a controlled manner. The layers may be attached to each other, pinned, or encapsulated by any suitable adhesive known to those skilled in the art to maintain the laminate structure.

[0102] Optionally or additionally, heat control articles may include a covering (coating). For example, a solution or emulsion of a polymer or prepolymer may be sprayed, painted, cast, or otherwise coated onto one or more outer surfaces of a silica-containing particulate composition or laminate and cured. Suitable cured polymers include polyolefins, silicones, polyvinyl alcohol, starch, polytetrafluoroethylene, phenolic resins, melamine, phenol-formaldehyde, acrylic polymers, and other polymers known to those skilled in the art. Such coverings (coatings) can provide functionality similar to the encapsulations discussed above, but using less material. Optionally or additionally, the silica-containing particulate composition may be surface-treated, for example, made hydrophobic. The silica-containing particulate composition may be contacted with hydrophobic agents such as silane compounds, silazane compounds, or disiloxane compounds. Examples of silane compounds include those having the formula R'. x SiX 4-x Alkyl halosilanes and having the formula R' x Si(OR”) 4-x Alkoxysilanes, wherein R' is selected from C1-C 10 Branched or straight-chain alkyl or alkenyl, C3-C 10 cycloalkyl and C6-C 10 The aryl group, preferably a C1-C4 branched or straight-chain alkyl or alkenyl group, where R” is a C1-C5 branched or straight-chain alkyl group, X is a halogen, preferably chlorine, and x is an integer from 1 to 3. The silica-containing particulate composition can be directly immersed in the hydrophobic agent or exposed to the vapor of the hydrophobic agent. Alternatively, the silica-containing particulate composition can be impregnated in a mixture of the hydrophobic agent and a suitable solvent. The temperature and pH of the treatment medium can be adjusted to manipulate the degree of treatment, as is known to those skilled in the art. Exemplary treatment agents include, but are not limited to, trimethylchlorosilane, dimethyldichlorosilane, hexamethyldisilazane, hexamethyldisiloxane, and other hydrophobic agents known to those skilled in the art. The hydrophobic agent is preferably water-soluble and / or has a boiling point of less than 200°C, less than 150°C, or preferably less than 100°C.

[0103] Silica-containing particulate compositions and / or heat-controlled articles may have a thickness of 0.3 to 6 mm, for example 0.3 to 5 mm, 0.4 to 4 mm, 1 to 3 mm, or 1.5 to 2.5 mm. In some embodiments, after drying the silica-containing particulate composition, for example during the assembly of the heat-controlled article, at least a portion of the component is compressed, for example between rollers or plates, to reduce the final thickness of the product article. Preferably, the silica-containing particulate compositions and / or heat-controlled articles are self-supporting. That is, silica-containing particulate compositions of particles, fibers, opacifiers and other particulate additives, as well as polymer binders and flocculation systems, can be processed and handled without loss of cohesion. Non-self-supporting silica-containing particulate compositions may require backing or burlap to maintain cohesion.

[0104] Silica-containing particulate compositions and / or heat-controlled articles exhibit excellent thermal stability. For example, according to ASTM-C356, heat-controlled articles shrink less than 2% after aging at 650°C. According to test method ASTM C518, silica-containing particulate compositions and / or heat-controlled articles have a thermal conductivity of less than 40 mW / mK at 25°C, preferably less than 30 mW / mK, such as 5 mW / mK to 25 mW / mK, or 8 mW / mK to 15 mW / mK, or 17 mW / mK to 30 mW / mK, or 15 mW / mK to 25 mW / mK, or 20 mW / mK to 30 mW / mK.

[0105] The silica-containing particulate composition and / or heat-controlled articles may have a tensile strength of 0.5 to 1.7 MPa, for example 0.6 to 1.5 MPa or 0.7 to 1.3 MPa.

[0106] Silica-containing particulate compositions and / or heat-controlled articles may be flexible, with properties measurable according to ASTM C1101 or another suitable technique. Manual bending tests can be useful, especially in the initial screening stage of products.

[0107] In certain implementations, silica-containing particulate compositions and / or heat control articles have a non-flammable flammability rating according to UL94-V0.

[0108] Optionally or additionally, the silica-containing particulate composition and / or heat-controlled article may be compressible. For example, it may have a compressive modulus of 0.1 to 100 MPa, such as 0.1-1 MPa, 1-10 MPa, 5-30 MPa, 10-50 MPa, or 30 to 100 MPa at 50% compression, as measured by ASTM C 165-05.

[0109] The invention is further illustrated in the following non-limiting illustrative section.

[0110] illustration

[0111] Nonwoven blankets containing pyrolytic silica particles, with or without aerogel particles, are produced using the materials listed in Table 1 below.

[0112] Table 1

[0113]

[0114] The pyrolytic silica particles (all from Cabot Corporation, CAB-O-SIL brand) are listed in Table 2 below. Carbon content was measured using a LECO CN928 analyzer.

[0115] Table 2

[0116]

[0117] The following is the production process for the insulating mat: According to the formulation in the following examples, the dispersant, flocculant, and defoamer were dispersed in water in a WARING benchtop heavy-duty blender to form a 1 liter white (process) aqueous concentrate. The concentrate was mixed under high shear for 10 seconds to form process water. The concentrate was then diluted to 2.5–3 liters of water, as shown in the following examples. After mixing, approximately 1.5 liters of diluted process water was transferred to the WARING blender. Chopped glass fibers, aerogel particles, titanium dioxide sand, silicon carbide, and aluminum hydroxide (ATH, ThermoFisher Scientific) were added to the WARING heavy-duty blender in the amounts listed in the examples. The mixture in the blender was mixed under high shear (15,000 rpm) for 40 seconds. Glass microfibers and pyrolytic silica were added to the blender, and the mixture was further blended under high shear for 40 seconds. Finally, silicone and polyurethane binders were added, and the mixture was further blended under high shear for 20 seconds to prepare a slurry, which was then added to the remaining process water. To destabilize the slurry system, a flocculant polymer was added to the slurry in the amounts shown in the examples below to generate flocs.

[0118] After flocculation, the slurry is discharged through a single-layer wet forming screen to produce a 30cm x 30cm blanket-like sheet. The blanket and forming screen are then passed through a vacuum to remove additional water from the flocculation. The sample is compressed to approximately 1-2mm thickness using heavy-duty rollers to squeeze out some water and flatten the blanket to a uniform surface. All blankets are removed from the forming screen and placed in a drying oven at 120°C for approximately 20 minutes.

[0119] Sample thickness was measured using a thickness gauge. Thermal conductivity was measured using a LaserComp heat flow meter at room temperature and 140°C according to ASTM C518; the standard deviation represents the standard deviation of two readings from the mean during the measurement period. After drying, blankets less than 2 mm thick were gently pressed between two pressure plates to flatten the surface, while blankets thicker than 2 mm were pressed between two pressure plates at room temperature at approximately 2 MPa to form a thin blanket not exceeding 2 mm in thickness. The final thicknesses are reported in the table below. Tensile strength (maximum load) was measured according to ASTM D5035, repeated three times.

[0120] Example 1

[0121] Experiments were conducted to evaluate the properties and / or performance of several nonwoven blankets containing CAB-O-SIL TS-530 pyrolytic silica (1-1, 1-2, 1-3) and HS-5 pyrolytic silica (1-4). All samples were prepared using 3L of process water.

[0122] Table 3

[0123]

[0124] Examples 1-1, 1-2, and 1-3 show that increasing the ratio of hydrophobic pyrolytic silica to aerogel slightly impairs thermal conductivity but significantly affects tensile strength. Replacing hydrophobic silica (1-1) with an equal amount of hydrophilic silica (1-4) with a moderately higher surface area does not affect thermal conductivity but significantly affects tensile strength.

[0125] Example 2

[0126] Experiments were conducted to evaluate the properties and / or performance of several nonwoven blankets containing CAB-O-SIL TS-610 pyrolytic silica. All samples were prepared using 3L of process water.

[0127] Table 4

[0128]

[0129] In this experiment, improved tensile strength was achieved using a 50 / 50 (w / w) blend of aerogel and silica.

[0130] Example 3

[0131] Experiments were conducted to evaluate the properties and / or performance of several nonwoven blankets containing CAB-O-SIL TS-610 pyrolytic silica, while varying the ratio of pyrolytic silica to fibers. All samples were prepared using 3L of process water.

[0132] Table 5

[0133]

[0134] In this experiment, tensile strength increased with increasing fiber ratio, but had no significant effect on thermal conductivity.

[0135] Example 4

[0136] Experiments were conducted to evaluate the properties and / or performance of several nonwoven blankets containing CAB-O-SIL TS-610 and TS-622 pyrolytic silica. All samples were prepared using 3L of process water; no aerogels were used in the formulations.

[0137] Table 6

[0138]

[0139] In this experiment, the tensile strength decreased as a higher surface area of ​​silica was used.

[0140] Example 5

[0141] Experiments were conducted to evaluate the properties and / or performance of several nonwoven blankets containing CAB-O-SIL M-5 pyrolytic silica (5-1, 5-2, and 5-3) and TS-720 pyrolytic silica (5-4). All samples were prepared using 3L of process water.

[0142] Table 7

[0143]

[0144] In Examples 5-1 and 5-2, the blankets have similar thermal conductivity to blankets prepared with hydrophobic silica, but generally have lower tensile strength. In Example 5-3, the blanket has lower tensile strength than that of Example 4-1, which was prepared with a similar silica-to-fiber ratio and similar fiber composition but with hydrophobic silica. Replacing hydrophilic M-5 silica with hydrophobic TS-720 silica (methanol value greater than 70) significantly reduced the tensile strength.

[0145] Example 6

[0146] Experiments were conducted to evaluate the properties and / or performance of several nonwoven blankets containing CAB-O-SIL TG-5110 pyrolytic silica. All samples were prepared using 2.5 L of process water.

[0147] Table 8

[0148]

[0149] The embodiments described above demonstrate that, using low-surface-area hydrophobic silica, tensile strength actually increases with the pyrolytic silica / aerogel ratio, wherein the increased pyrolytic silica loading has little effect on thermal conductivity.

[0150] Example 7

[0151] Experiments were conducted to evaluate the properties and / or performance of several nonwoven blankets containing CAB-O-SIL TG-3130 pyrolytic silica. All samples were prepared using 2.5 L of process water.

[0152] Table 9

[0153]

[0154] The results showed that blankets made with TG-3130 silica containing more than 6% by weight of carbon exhibited significantly lower tensile strength than blankets made with TG-5110 silica containing no more than 6% by weight of carbon.

[0155] Example 8

[0156] A bag with one open end (a VacMaster vacuum chamber storage bag, approximately 150mm x 200mm, with walls 3 mils (0.76mm) thick) is placed in a mold with a 5mm gap. The mold is prepared by clamping two ¾” (19mm) clamps together, each clamp being approximately 9.5” (24.1cm) squares with spacers (two paint stirrers) on both sides to create a cavity of appropriate size. ENTERA EV5400 or ENTERA EV5200 aerogel is filled into the bag, and the bag is ensured to be completely filled by vibrating and tamping the mold. The filled bag is then hand-compressed under a load of approximately 5psi and then evacuated using a Vacmaster VP320 meatpacking machine until approximately 90% vacuum is achieved. The evacuated storage bag is expected to have a thermal conductivity of 14-17mW / mK and a thickness of 5-7mm. The same procedure was used to fill the same designed bags with a 50 / 50 (w / w) mixture of ENTERA EV5200 aerogel and TS-530 pyrolytic silica. The evacuated storage bags had a thermal conductivity of 9.3 mW / mK.

[0157] Bags of the same design were filled with a predetermined weight of ENTERA EV5400 aerogel. The desired weight was 110 kg / m³ in a 150 mm × 200 mm × 4 mm storage bag. 3The desired weight for the final density is determined. The bag is then hand-compressed under rollers using two tracks to maintain the desired thickness of the filled bag at approximately 5 mm. The rollers are rolled back and forth until the aerogel appears evenly dispersed. The package is then placed in a Vacmaster VP320 meatpacking machine and evacuated. The thermal conductivity is expected to be 14-17 mW / mK.

[0158] While the invention has been specifically shown and described with reference to preferred embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the scope of the invention as covered by the appended claims.

Claims

1. A composition comprising a mixture of the following: a) silica aerogel particles having a particle size in the range of 0.1 mm to 5 mm and b) grape-like particles containing hydrophobic silica having a carbon content of up to 6% and a methanol value of 30 to 70. The silica aerogel particles and the hydrophobic silica-containing particles are present in a ratio of 0:100 to 80:20; and The composition described herein has a thermal conductivity of about 5-40 mW / mK at 25°C and a thickness of 0.1-10 mm.

2. The composition according to claim 1, wherein the grape-like particles containing hydrophobic silica are selected from pyrolytic silica, silicon-treated carbon black, silica-coated carbon black, pyrolytic mixed metal oxides, and silica-carbon black composite particles.

3. The composition according to any one of the preceding claims, wherein the particles containing hydrophobic silica are hydrophobic pyrolytic silica.

4. The composition according to any one of the preceding claims, wherein the particles containing hydrophobic silica are hydrophobized by hydrophobic silane or silazane.

5. The composition according to any one of the preceding claims, wherein the hydrophobic silica-containing particles are surface-treated with a silica treatment agent and have a particle size of 60 to 340 μm. 2 / g, preferably 60 to 250m 2 / g of surface area of ​​pyrolytic silica particles.

6. The composition according to any one of the preceding claims, wherein the hydrophobic pyrolytic silica has a methanol value of 45 to 70.

7. The composition according to any one of the preceding claims, wherein the hydrophobic silane is R 4-n SiX n , where n is 1-3, each R is independently selected from hydrogen, C1-C30 branched or straight-chain alkyl or alkenyl, C3-C18 haloalkyl, C3-C10 cycloalkyl, and C6-C14 aromatic groups, and each X is independently C1-C18 branched or straight-chain alkoxy or halogen.

8. The composition according to any one of the preceding claims, wherein the hydrophobic silane is R 4-n SiX n , where n is 1-3, each R is independently selected from hydrogen and C1-C4 branched or straight-chain alkyl or alkenyl, and each X is independently C1-C18 branched or straight-chain alkoxy or halogen.

9. The composition according to claim 7 or claim 8, wherein no more than three groups R are hydrogen.

10. The composition according to any one of the preceding claims, wherein the mixture further comprises fibers.

11. The composition according to any one of the preceding claims, wherein the fiber is glass fiber, ceramic fiber, synthetic polymer fiber, carbon fiber, natural polymer fiber, mineral wool, or a mixture of two or more of these.

12. The composition according to any one of the preceding claims, wherein the fibers are blackened or metal-coated.

13. The composition according to any one of the preceding claims, wherein at least a portion of the silica aerogel present in the heat control component is combined with a light-blocking agent.

14. The composition according to any one of the preceding claims, wherein at least a portion of the silica aerogel is covered or impregnated with a heat-absorbing material.

15. The composition according to any one of the preceding claims, wherein the mixture further comprises one or more components selected from the group consisting of: fibers, light-blocking agents, flame retardants, heat-absorbing materials, phase change materials, adhesives, defoamers, dispersants, emulsifiers, surfactants, and flocculants.

16. The composition according to any one of the preceding claims further comprises a sheet or felt, said sheet or felt comprising silicone, polyvinylidene fluoride, chlorinated polyethylene, aromatic polyamide fiber, or aromatic polyamide aerogel.

17. The composition according to any one of the preceding claims further comprises an encapsulating agent for encapsulating the mixture.

18. A heat control component comprising the composition of any one of the preceding claims.

19. The heat control component according to claim 18, wherein the heat control component is in the form of a blanket or a pressed pad.

20. The heat control component according to claim 18 or claim 19, wherein the heat control component meets the UL94 V0 specification.

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