Aerogel fireproof thermal insulation coating and preparation method thereof

Abstract

The application discloses an aerogel composite coating with smokeless, high fireproof and high thermal insulation characteristics and a preparation method thereof, comprising the following steps: (1) mixing hydrolysis, (2) condensation dispersion, (3) normal pressure drying, (4) high-temperature-resistant glue mixing, and (5) blending and dispersing. In the technology, the aerogel wet glue particles with uniform particle size can be prepared by using suspension condensation dispersion for aerogel fusion glue, and after normal pressure hot air drying, the aerogel composite coating with smokeless, high fireproof and high thermal insulation characteristics can be prepared by mixing with a high-temperature-resistant glue solution. The product developed in the application can resist heat up to 1200 DEG C or above, and when sprayed on an aluminum plate, the aluminum plate can be prevented from being burned through by a 1200 DEG C high-temperature flame impact, and can be applied to the safety protection of electric vehicle lithium battery modules in thermal runaway.

Description

Technical Field

[0001] This invention relates to a high-temperature resistant aerogel fireproof and heat-insulating coating, and more particularly to an aerogel composite coating that combines smokelessness, high heat insulation and high fire resistance, and its preparation method. Background Technology

[0002] As is well known, aerogel is a porous material with a three-dimensional network structure, a porosity higher than 80% (and even higher than 95%), and a low density (approximately 0.005 to 0.2 g / cm³). 3 High specific surface area (500 to 2000 m²) 2 / g), low thermal conductivity (k=15 to 40 mW / mk) and low dielectric properties (D k =1.3 to 2.0), low dielectric loss (D fProperties such as a porosity (below 0.003) make aerogels or their composites possess excellent properties such as high thermal insulation, high fire resistance, and low dielectric constant. Due to their high porosity and extremely low density, aerogels or their composites are highly valuable in applications requiring high thermal insulation, high fire resistance, low signal transmission resistance, and high resistance to electrical shock. Therefore, they hold a strategic position in future applications across various industries, such as high-temperature fire protection, energy-intensive production equipment, and energy-saving and carbon-reduction applications in pipelines. While general organic foam materials currently offer good thermal insulation at room temperature or below 120°C, their manufacturing process causes environmental pollution. Furthermore, when applied to environments above 120°C, these products rapidly decompose and lose their insulation properties, limiting their application at 120°C or higher. Additionally, current high-temperature fire-resistant and thermal-insulating coatings are primarily thermally expandable organic coatings. These products are made by mixing organic coatings with thermally expandable metal oxides. Thermally expanding metal oxides achieve fireproofing and heat insulation effects under high-temperature flames by utilizing the thermal expansion properties of metal oxides or carbon. However, in high-temperature applications, organic coatings such as epoxy resins will carbonize and decompose under flames above 500°C, forming toxic substances such as dioxins. Furthermore, the thermally expanded metal oxide layer will crack and peel off under high-temperature flames, resulting in the loss of its protective properties. Therefore, these thermally expanding metal oxide organic fire-retardant coatings cannot achieve long-term fireproofing and heat insulation effects at temperatures between 800 and 1200°C. Thus, when lithium battery modules in electric vehicles experience thermal runaway and instantaneous high-temperature flames of 800 to 1200°C, as well as explosive impacts, the fireproofing and heat source blocking properties of thermally expanding metal oxide organic fire-retardant coatings are not superior. Therefore, future development of superior fire-retardant coatings to replace traditional thermally expanding metal oxide organic fire-retardant coatings is necessary for thermal runaway protection of lithium battery modules in electric vehicles. Aerogel is a material with a nanoporous inorganic silica three-dimensional network structure. Aerogel or its related composite materials can replace traditional organic foaming materials, thermally expandable metal oxides, or thermally expandable carbon additives in organic fire-retardant coatings to form novel fire-resistant and heat-insulating products. Basic materials theory tells us that the abundant nanoporous structure within aerogel materials significantly reduces heat transfer; therefore, the higher the porosity of the material structure, the better its heat insulation properties. Furthermore, inorganic silica aerogel materials are highly fire-resistant, resistant to high temperatures, and do not burn or spread heat. Therefore, nanoporous silica aerogel materials, in addition to preventing heat loss, also possess high fire-resistant properties. This is essential for the safety protection of future electric vehicle lithium battery modules in cases of thermal runaway or next-generation high-temperature melting batteries.In response, our invention team aims to develop an aerogel fire-resistant and heat-insulating coating that combines high fire resistance, high heat insulation, and is smokeless and non-toxic, specifically addressing the safety protection needs of aerogel-related products for electric vehicle lithium battery modules in the face of thermal runaway or new-generation high-temperature molten batteries. Effectively addressing the safety hazards of thermal runaway in electric vehicle lithium battery modules or new-generation high-temperature molten batteries is a pressing goal. Currently, various heat-insulating coatings or high-temperature fire-resistant coatings disclosed in international patents still have the aforementioned concerns, especially at temperatures above 600°C. The currently disclosed technologies use aerogels with added organic coatings (e.g., epoxy resin, polyamide ester, polyacrylate, etc.). These products have a maximum heat resistance of approximately 200°C. Prolonged exposure to high temperatures will cause these organic coatings to gradually carbonize and decompose, potentially producing toxic gases. The shortcomings of these fire-resistant and heat-insulating coatings remain a significant and unresolved issue regarding thermal runaway in electric vehicle lithium battery modules.

[0003] Traditional aerogel preparation methods utilize a sol-gel synthesis, primarily involving mixing precursors such as alkoxysilanes, methyl orthosilicate, or water glass with a large amount of organic mixed solvents, followed by the addition of an acid catalyst for hydrolysis. After a certain period of hydrolysis, an alkaline catalyst is added to initiate a condensation reaction, during which a sol gradually forms. Within the sol, molecules continue to react and bond, gradually forming a semi-solid polymeric gel. This is then aged for a period to allow the gel to develop a stable three-dimensional network structure. Finally, a hydrophobic solvent such as n-butanol, n-hexanol, n-hexane, or cyclohexane is used for solvent displacement, followed by supercritical drying to extract and dry the solvent from the aerogel structure. Traditional processes not only consume large amounts of expensive organic solvents and require supercritical equipment, but also necessitate lengthy solvent displacement with hydrophobic solvents, making aerogel preparation costly and time-consuming.

[0004] On the other hand, the preparation method of hydrophobic aerogels also employs the sol-gel synthesis method. This primarily involves mixing methyl alkyl silicate precursors such as methyltrimethoxysilane (MTMS) or methyltriethoxysilane (MTES) with an organic solvent, followed by the addition of an alkaline catalyst to initiate a hydrolysis reaction. After a certain period of hydrolysis, a condensation reaction occurs, gradually forming a sol. Within the sol, molecules continue to form reactive bonds, gradually creating a semi-solid polymeric gel. After a period of aging, solvent replacement is performed for two to three days using solvents such as isopropanol, acetone, n-hexane, or cyclohexane, allowing the hydrophobic gel to form a stable three-dimensional network structure. Finally, the solvent in the aerogel structure is dried using atmospheric pressure drying technology to obtain a porous, dried aerogel block. The preparation process of hydrophobic aerogels also requires large amounts of expensive organic solvents and a long period of solvent replacement with alcohols or alkanes, making it time-consuming and costly.

[0005] The aforementioned aerogel preparation methods all require the use of large amounts of hydrophobic solvents, such as alkanes and other organic solvents, for multiple solvent replacements over two to three days. Supercritical drying or atmospheric pressure-high temperature drying is then employed to prevent the aerogel structure from shrinking or cracking due to the surface tension of water molecules during atmospheric pressure drying. "Supercritical drying" refers to the supercritical state of water and organic solvents under high temperature and pressure, allowing both to possess gas-liquid mixing properties. The solvent is then directly vaporized and dried under supercritical conditions. Therefore, residual solvent in the network structure can be removed under supercritical conditions without causing the wet gel to shrink. However, the use of multiple hydrophobic solvent replacements and supercritical drying in these processes is time-consuming and expensive, hindering the mass production and future competitiveness of aerogels. The aforementioned hydrophobic modification utilizes a multi-stage solvent replacement technique at ambient temperature and pressure, but this modification requires more than 24 hours, making the process too time-consuming and cost-inefficient.

[0006] The invention patent publication number CN106479297A describes an "aerogel-based water-based intumescent fire-retardant coating and its preparation method," which relates to providing an aerogel-based water-based intumescent fire-retardant coating and its preparation method. The fire-retardant coating comprises the following components by weight: 10-50 parts emulsion, 30-70 parts intumescent flame retardant, 0.1-10 parts first neutralizer, 1-10 parts plasticizer, 2-20 parts flux, 0.1-10 parts first dispersant, 0.1-10 parts first stabilizer, 5-20 parts aerogel slurry, and 5-60 parts pigments and fillers; wherein the emulsion is a mixture of core-shell type silicone-modified acrylate emulsion and pure acrylic emulsion. The aforementioned aerogel water-based intumescent fire-retardant coating uses silicone-modified acrylate emulsion and pure acrylic emulsion as the emulsion system. The silicone-modified acrylate emulsion possesses excellent weather resistance, stain resistance, good air permeability, and high hydrophobicity, as well as superior expansion effect and fire-retardant performance. The pure acrylic emulsion improves the mechanical properties of the fire-retardant coating, such as adhesion, ensuring the effective performance of the carbonized coating's fire-retardant properties. It exhibits good fire resistance, stable performance, and is easy to produce. The emulsion is a mixture of core-shell silicone-modified acrylate emulsion and pure acrylic emulsion. The aerogel water-based intumescent fire-retardant coating is characterized in that the core-shell silicone-modified acrylate emulsion is prepared by a silicone-acrylic emulsion polymerization reaction of a mixture of vinyltriethoxysilane and styrene with a mixture of butyl acrylate and methyl methacrylate.

[0007] The invention disclosed in Chinese Invention Patent Publication No. CN107267006A, entitled "An Aerogel Waterborne Thermal Insulation and Fireproof Coating and Its Preparation Method," mainly relates to an aerogel waterborne thermal insulation and fireproof coating and its preparation method. It is primarily composed of aerogel powder, waterborne resin, and a flame retardant. The aerogel powder consists of an internal hydrophobic layer and a surface hydrophilic layer, with the surface hydrophilic layer having a thickness of 0.1~100μm. The preparation method of the aerogel waterborne thermal insulation and fireproof coating disclosed in this invention includes the following steps: (1) modification of the aerogel powder; (2) mixing the aerogel powder from step (1) with the waterborne resin and the flame retardant, followed by stirring or ball milling. This invention adds aerogel powder to the waterborne coating system, ensuring that the nanoporous structure of the aerogel is not damaged, fully utilizing the thermal insulation performance of the aerogel, and improving the fire resistance limit of the coating. The aerogel water-based heat-insulating and fire-retardant coating provided by this invention can be applied to steel structures, wood, concrete structures, tunnels, cables, and other fields. It features a simple and practical preparation process, excellent performance, and low cost, making it suitable for industrial production. Its main characteristics are that it is composed primarily of aerogel powder, water-based resin, and flame retardant. The aerogel powder consists of an internal hydrophobic layer and a surface hydrophilic layer, with the surface hydrophilic layer having a thickness of 0.1~100μm.

[0008] The invention patent publication number CN107858050A describes a "SiO2 aerogel thermal insulation coating and its preparation method," which relates to a SiO2 aerogel thermal insulation coating comprising the following components by weight: 50-100 parts of base paint, 5-20 parts of SiO2 aerogel, 2-10 parts of hollow glass microspheres with a titanium dioxide coating, 0.05-0.2 parts of dimethyl hydroxy silicone oil, 0.05-0.2 parts of hexadecyltrimethylammonium bromide, 10-25 parts of curing agent, and 2-10 parts of additives; the additives include dispersants, wetting agents, defoamers, and leveling agents. In this SiO2 aerogel thermal insulation coating, the SiO2 aerogel, combined with coated hollow glass microspheres, synergistically enhances the thermal insulation effect. The method provided by this invention yields a thermal insulation coating with excellent homogeneity, characterized by comprising the following components by weight: 50-100 parts base paint, 5-20 parts SiO2 aerogel, 2-10 parts hollow glass microspheres with a titanium dioxide coating, 0.05-0.2 parts dimethyl hydroxy silicone oil, 0.05-0.2 parts hexadecyltrimethylammonium bromide, 10-25 parts curing agent, and 2-10 parts additives; the additives include dispersants, wetting agents, defoamers, and leveling agents.

[0009] The invention described in Chinese Invention Patent Publication No. CN107858050A, entitled "A SiO2 Aerogel Thermal Insulation Coating and Its Preparation Method," relates to a method for preparing a gel-fiber composite by wetting a fiber material comprising at least one of inorganic and organic fibers; laminating the wetted fiber material and the spacer in a wound structure or in a planar form; filling the fiber material into a container; preparing a gel-fiber composite by injecting a precursor into the container and simultaneously removing residual air bubbles under vacuum while gelling the precursor; removing the aerogel-fiber composite and the spacer from the container; modifying the gel-fiber composite with solvent substitution and organic surface treatment; and then drying the organically modified gel-fiber composite by atmospheric pressure drying or supercritical drying.

[0010] The invention patent publication number CN107858050A describes a method for preparing a super heat-insulating coating made of reinforced silica aerogel. The method includes the following steps: S1, adding 1 part tetraethyl orthosilicate and 0.2-0.5 parts titanium tetrachloride to a mixed solution of 10 parts ethanol and 2-10 parts pure water, and stirring to obtain a solution; S2, adding a mixed solution of ammonia and ethanol to obtain a sol; S3, casting the sol into a mold and aging it to obtain a wet gel; S4, impregnating the wet gel with a hexane solution of trimethylchlorosilane to perform hydrophobic modification; S5, drying under normal pressure and then crushing to obtain gel powder; S6, adding 100 parts of gel powder F to 10-50 parts of a coating, adding 2-6 parts of dispersant, 2-6 parts of defoamer, and 2-6 parts of leveling agent, and stirring at high speed to obtain the finished coating. The product prepared by this invention has advantages such as high strength and good thermal insulation. The finished product quality and construction quality of the aerogel coating are good, and it is suitable for both water-based and oil-based coatings, making it suitable for widespread application. The coating is a water-based coating, specifically a water-based polyurethane, water-based epoxy resin, or water-based alcohol ester resin.

[0011] The "Aerogel Invisible Fireproof Coating" described in Chinese Invention Patent Publication No. CN108587264A involves an aerogel invisible fireproof coating, comprising two stages: hydrophobic reinforcement modification of silica aerogel and coating preparation. The raw materials used in the silica aerogel hydrophobic reinforcement modification stage include: water glass, carbon nanofibers, anhydrous ethanol, acetone, n-butanol, hexadecyltrimethylammonium bromide, trimethylchlorosilane, styrene exchange resin, ammonia, and kerosene. The raw materials used in the coating preparation stage include hydrophobically reinforced silica aerogel modified in the above steps, sodium sulfite, talc, sodium chloride, char-forming catalyst, char-forming agent, foaming agent, and antioxidant. Pentaerythritol is added as a char-forming agent to expand the carbon source in the carbon layer and enhance the aerogel's barrier function.

[0012] Chinese Invention Patent Publication No. CN112745698A, entitled "A Method for Preparing Modified Aerogel, Modified Aerogel, Thermal Insulation Coating and Its Application," relates to a method for preparing modified aerogel, modified aerogel, thermal insulation coating and its application. The method for preparing the modified aerogel includes the following steps: adding a certain amount of modifier to a certain amount of aqueous alcohol solution, adding a certain amount of silane coupling agent, stirring at a certain temperature for a certain time, adding a certain amount of aerogel, continuing stirring for a certain time, washing and drying to obtain the modified aerogel. The modifier includes one or more of glass microspheres, SiO2, fibrous alumina, and fibrous silica. The modified aerogel prepared using this method can be uniformly dispersed in an aqueous solvent system without damaging its microstructure, and also possesses excellent mechanical strength, making it suitable as a filler to meet the requirements for coating hardness and adhesion. The coating is made by mixing modified aerogel into 55ml of silicone resin emulsion, adding polyether dispersant and silicone defoamer, stirring for 30 minutes to disperse evenly, adding hydroxypropyl cellulose, and continuing to stir until uniform; finally, adding chitosan and mica powder, stirring evenly, and the heat insulation coating is obtained.

[0013] The "Nano-Silicone Aerogel Thermal Insulation Coating and its Preparation Method" described in Chinese Invention Patent Publication No. CN113831765A relates to a nano-silicone aerogel thermal insulation coating and its preparation method. The method primarily involves finely grinding a prepared silica aerogel dispersion using a roller ball mill to create a novel nano-silicone aerogel dispersion. This nano-silicone aerogel dispersion is then further mixed thoroughly with a specially selected composite solid filler to prepare the novel nano-silicone aerogel thermal insulation coating. This coating exhibits advantages such as easy application, good adhesion, high hardness, weather resistance, and excellent thermal insulation performance. The water-based coating comprises at least one of water-based acrylic, acrylic emulsion, styrene-acrylate emulsion, and vinyl acetate-acrylic emulsion.

[0014] The "A Thick Aerogel Thermal Insulation Textured Coating" disclosed in Chinese Invention Patent Publication No. CN113881300A relates to a thick aerogel thermal insulation textured coating. This coating comprises the following components by weight: 6 parts silica aerogel, 0.45 parts wetting agent, 0.5 parts dispersant, 13 parts deionized water, 0.35 parts defoamer, 72 parts water-based acrylic resin, and 7.7 parts film-forming aid. This invention uses silica aerogel as a functional filler, and its thermal insulation performance is far superior to that of titanium dioxide, glass microspheres, and far-infrared ceramic powder coatings. This is because the nanopores and unique three-dimensional network structure of silica aerogel disrupt the heat conduction pathway of the matrix, and its unique nanostructure restricts the free flow of air molecules, inhibiting air convection and resulting in an extremely low thermal conductivity. Therefore, using silica aerogel as a filler in this coating can maximize its thermal insulation performance.

[0015] The invention patent announcement CN108997911B, entitled "An Aerogel Fireproof and Heat-Insulating Coating and Its Preparation Method," relates to an aerogel fireproof and heat-insulating coating and its preparation method. By adding hydrophilically modified aerogel powder and ceramized powder, and then adding additives and fillers in different formulation ratios, a coating with fireproof and heat-insulating properties is prepared. Utilizing the performance characteristics of the three-dimensional network structure of aerogel, the coating overcomes the shortcomings of existing coatings that only provide fire protection but not heat insulation, thus giving it heat-insulating properties. Simultaneously, nano-ceramic powder is added to the coating. Upon heating, the nano-ceramic powder in the coating ceramizes, forming an expanded ceramic film on the substrate surface. An air layer exists between this film and the substrate, isolating the flame from contacting the surface of the vehicle's metal materials. Furthermore, the low thermal conductivity of the aerogel in the coating prevents heat transfer to the metal surface. This synergistic effect of fire prevention and heat insulation ensures that the metal parts of the vehicle effectively block heat and flames, whether in normal use or in the event of an extreme fire. The resin emulsion is characterized by comprising one or more of the following: water-based acrylic emulsion, water-based polyurethane emulsion, and water-based epoxy resin emulsion.

[0016] The invention described in Chinese Invention Patent Publication No. CN112226137B, entitled "An Aerogel Thermal Insulation Coating and Its Preparation Method," relates to an aerogel thermal insulation coating and its preparation method. It is prepared by means of the following components in parts by weight: 40wt%-60wt% aldehyde-ketone resin, 20-40% activated carbon, 10wt%-15wt% nano-silica, 5wt%-10wt% aerogel, and 2wt% dispersant. The aerogel thermal insulation coating prepared by this invention has good thermal insulation and air purification effects, and is particularly suitable for thermal insulation and anti-corrosion treatment of the interior surfaces of vehicles. Its key feature is that the aldehyde-ketone resin used in the aerogel thermal insulation coating for the interior metal surfaces of vehicles is at least one of KR-120 aldehyde-ketone resin and KR-80F aldehyde-ketone resin.

[0017] The invention described in Chinese Invention Patent Publication No. CN112500770B, entitled "A High-Temperature Aerogel Thermal Insulation and Fireproof Coating and Its Preparation Method," relates to a high-temperature aerogel thermal insulation and fireproof coating made from the following raw materials in parts by weight: 10-20 parts aerogel powder, 35-46 parts organic binder, 15-20 parts inorganic binder, 12-15 parts filler, 2-3 parts toughening agent, 10-15 parts flame retardant, and 50-60 parts deionized water. The invention also discloses a method for preparing the high-temperature aerogel thermal insulation and fireproof coating. The high-temperature aerogel thermal insulation and fireproof coating provided by this invention has good thermal insulation and fireproof properties. The organic binder is one or more of unsaturated polyester emulsion, PVC emulsion, epoxy resin emulsion, acrylic resin emulsion, silicone resin emulsion, and alkyd resin emulsion; the inorganic binder is one or more of cement mortar, gypsum powder, and silicates.

[0018] Chinese Invention Patent Publication No. CN113292894B describes an "aerogel coating and an aerogel coating obtained from the aerogel coating," which relates to an aerogel coating comprising: a film-forming emulsion; a SiC-SiO2 composite aerogel; a dispersant; a wetting agent; a defoamer; rutile titanium dioxide nanoparticles; hollow glass microspheres; a thickener; a film-forming aid; ammonia; and deionized water as the balance. Furthermore, this invention discloses an aerogel coating obtained from the aerogel coating. This aerogel improves surface energy and the bonding area of ​​secondary particles, thereby improving mechanical properties and thermal insulation properties. In this aerogel coating, the film-forming emulsion is selected from a flexible acrylic emulsion with a solid content of 50-60%.

[0019] The invention described in Chinese Invention Patent Publication No. CN114479602B, entitled "A Repair Coating for Aerogel Surface Defects, Its Preparation Method and Application," relates to a repair coating for aerogel surface defects, its preparation method and application, and is applied to the surface of phenolic aerogel materials to be repaired. The mass fraction of each component in the repair coating is: 10-70% phenolic resin solution, 10-30% aerogel, 10-30% nano-inorganic oxides, and 10-30% inorganic fibers. The repair coating provided by this invention can be used for repairing defects in phenolic aerogel materials, is simple to operate, has excellent compatibility with phenolic aerogel materials, and possesses excellent maintainability and ablation resistance.

[0020] The "Preparation Method of Nano-Silicone Aerogel Thermal Insulation Coating" described in Taiwan Invention Patent Publication No. TWI770931 relates to a method for preparing a nano-silicone aerogel dispersion, which involves the following steps: (1) Dissolving Triton X-100 in an aqueous solution to form a first solution, wherein the amount of Triton X-100 is between 0.1 and 1.2 grams and the amount of aqueous solution is between 15 and 30 grams; (2) Adding a silica aerogel to the first solution and continuously stirring mechanically to obtain a silica aerogel slurry; (3) Mixing sodium dodecylbenzenesulfonate, sodium dodecyl polyoxyethylene ether sulfate, hydroxycellulose thickener, and aqueous solution, and continuously stirring to form a second solution, wherein the amount of sodium dodecylbenzenesulfonate is between 0.3 and 1.2 grams, the amount of sodium dodecyl polyoxyethylene ether sulfate is between 0.05 and 1 gram, the amount of hydroxycellulose thickener is between 0.1 and 0.3 grams, and the amount of aqueous solution is between 15 and 30 grams. (4) Add an aqueous acrylic to the second solution and stir continuously until homogeneous to obtain a third solution. The ratio of the amount of aqueous acrylic is between 30 and 50 grams. (5) Add the third solution to the silica aerogel slurry and stir continuously until homogeneous to obtain a silica aerogel dispersion. (6) Place the silica aerogel dispersion on a roller mill for grinding to produce grinding fluid. Zirconia beads with a size of 2 mm are selected for grinding, and the ball filling ratio is 1:1 of the silica aerogel volume. (7) Finally, filter the grinding fluid containing the grinding balls with a filter screen to obtain a nano silica aerogel dispersion.

[0021] The applicant's invention, as described in Taiwan Patent Publication No. TWI793839, entitled "Low-Dielectric Electrogel Powder, Low-Dielectric Electrogel Suspension, Composite Membrane and Preparation Method Thereof," relates to the preparation and application of a high-purity aerogel powder with low dielectric constant and low dielectric loss. The preparation is accomplished through the following steps: (1) mixing and hydrolysis, (2) condensation and dispersion, and (3) drying. This process improves upon sol-gel technology, eliminating the need for large amounts of organic solvents and surfactants in the reaction. Therefore, this process can prepare high-purity aerogel powder materials with low dielectric loss without solvent replacement or deionized water rinsing. The density of the low-dielectric electrogel is between approximately 0.05 and 0.12 g / cm³. 3 Because there are no other impurities in the process, the thermal conductivity and dielectric loss are significantly reduced. The thermal conductivity of the aerogel powder is about 0.013 to 0.016 W / mk, the dielectric constant of the aerogel powder is about 1.28 to 1.8, and the dielectric loss is 0.0012 to 0.0036. In addition, the dry powder or semi-dry powder is further dispersed with an organic solvent to form an organic solvent-containing aerogel suspension. Its preparation can be completed by the following steps: (4) impregnation with a specific organic solvent, (5) three-roller refining, and (6) uniform mixing with a specific polymer concentrated solution. The preparation of the suspension formed by impregnation with a specific organic solvent can be adjusted according to the solvent of the specific polymer concentrated solution. After drying, the mixed specific polymer concentrated solution forms a uniform and porous low dielectric composite film, especially a low dielectric polymer composite film with a thickness of less than 300 μm. It can be used as a dielectric layer in high-frequency circuits, an insulating layer in semiconductor devices, or a microwave circuit in communication integrated circuits.

[0022] Furthermore, the "Low-Dielectric Gel and its Preparation Method" described in the Taiwan Invention Patent Publication No. TWI764584 by the applicant relates to the preparation and application of a low-dielectric organic / inorganic aerogel composite material formed by impregnating a low-dielectric gel into a polymer solution. The preparation is completed through the following steps: (1) mixing, (2) hydrolysis, (3) condensation, (4) aging, (5) drying, (6) impregnation with a polymer solution, (7) curing and phase separation, and (8) drying and crosslinking. This process produces a high-strength low-dielectric organic / inorganic aerogel composite material. The low-dielectric gel has a porous structure with a porosity of over 70% and a density of approximately 0.12 to 0.45 g / cm³. 3 Its dielectric properties decrease with increasing porosity, with a dielectric constant of 1.28 to 1.89 and a dielectric loss of 0.012 to 0.023. It can be used as a dielectric layer in high-frequency circuits, an insulating layer in semiconductor devices, or a material for microwave circuits in communication integrated circuits.

[0023] Furthermore, the "Preparation Method of Hydrophobic Aerogel Composite Gel for Cold Protection and Heat Insulation and Related Products" described in Taiwan Invention Patent Publication No. TWI760728 by our team involves a method for preparing a hydrophobic aerogel composite gel, comprising the following steps: (S1) mixing step; (2) hydrolysis step; (3) condensation step; (4) aging step; (5) high-temperature pulse water washing step; (6) drying step; and (7) composite step. The hydrophobic aerogel composite gel is a highly viscous colloid formed by mixing the prepared hydrophobic aerogel with inorganic fibers, inorganic adhesives, and natural cellulose binders. The developed products, in addition to having excellent cold protection and heat insulation properties, also have advantages such as appropriate strength, light weight, good flame retardancy, and good water repellency.

[0024] Furthermore, the applicant's invention patent publication number TWI717257, "Preparation method of high-temperature resistant, heat-insulating, and fire-resistant aerogel / inorganic fiber composite material and application of the product," relates to a preparation method of a hydrophilic aerogel / inorganic fiber composite material comprising the following steps: (1) mixing step; (2) hydrolysis step; (3) condensation step; (4) aging step; (5) high-temperature solvent replacement step; (6) evaporation and drying step; and (7) composite step. The resulting product is a viscous aerogel composite material composed of aerogel particles, inorganic fibers, inorganic binders, and natural cellulose binders, with the content of aerogel and inorganic fibers after drying being 25-90 wt%. In addition, the resulting product can be used for a long time at temperatures above 600°C without the phenomenon of organic matter decomposition and the generation of carcinogens.

[0025] While the aforementioned existing technologies all relate to the manufacturing technology of aerogel organic thermal insulation coatings or thermally expanding organic coatings, these technologies all utilize the thermal expansion of inorganic materials at high temperatures, several to tens of times, using the expanded air layer for thermal insulation. However, the gaps between lithium battery packs in electric vehicles are currently extremely thin. Using these thermally expanding products under conditions of lithium battery thermal runaway would lead to other lithium batteries being damaged by high-pressure compression. These existing technologies generally utilize aerogels or a mixture of aerogels and inorganic powders with organic coatings, such as epoxy resins and waterborne polyamide ester coatings. Water-based coatings, commonly known as water-based PU coatings and water-based polyacrylic coatings (commonly known as water-based acrylic coatings), often have the disadvantage that their maximum heat resistance temperature is mostly below 200°C. Therefore, these existing technologies utilize the addition of flame retardants to improve the heat resistance temperature. The organic coatings used in these existing technologies will gradually age under prolonged sunlight, leading to a decrease in the coating effect and causing a large number of aerogel particles to fall off. In addition, in environments above 200°C, the organic coatings will age and decompose rapidly, resulting in the aerogel insulation coating falling off and producing toxic fumes.

[0026] The high-temperature decomposition of the above-mentioned organic coatings, resulting in the leakage of aerogel dust or the peeling off of thermal insulation coatings and the generation of toxic fumes, will cause pollution in high-tech components such as cleanrooms or electric vehicles. This is the biggest drawback of aerogel organic thermal insulation coatings. Therefore, silicon-based aerogel organic thermal insulation coatings or thermally expandable fire-retardant coatings are extremely prone to generating nano- to micron-sized dust pollutants during high-temperature applications. This aerogel dust has always been a major obstacle preventing the rapid application of aerogel in high-tech industries. The above-mentioned drawbacks of fire-retardant and thermal insulation coatings have been the main concerns or major problems preventing the application of high-insulation aerogel energy-saving materials in high-tech industrial production lines, particularly regarding the thermal runaway of electric vehicle lithium battery modules.

[0027] In response to the shortcomings in application caused by the aforementioned aerogel dust pollutants, the inventor conceived of an improvement idea and conducted in-depth research and development. After a long period of effort, this invention was finally born. The main purpose of this invention is to provide a silicon-based aerogel fireproof and heat-insulating coating that is smokeless, non-toxic, and has high fire resistance and high heat insulation performance under high-temperature flames, as well as its preparation method. Summary of the Invention

[0028] Therefore, to improve upon the shortcomings of current heat-insulating or fire-retardant coatings made from epoxy resin, waterborne polyamide ester coatings, waterborne polymethyl methacrylate coatings mixed with aerogel or thermally expandable metal oxides, such as the tendency of organic coatings to aging and decompose, leading to aerogel dust shedding, during prolonged sun exposure and in high-temperature environments above 300°C, or the rapid burning of these organic coatings under flames above 500°C generated by thermal runaway of lithium battery modules, the main objective of this invention is to provide a preparation method for preparing aerogel fire-retardant and heat-insulating coatings. These aerogel fire-retardant and heat-insulating coatings are silicon-based aerogel fire-retardant and heat-insulating coatings that exhibit smokeless and non-toxic properties, high fire resistance, and high heat insulation performance under high-temperature flames. They can be applied to high-temperature processes in cleanrooms and for safety protection against thermal runaway of electric vehicle lithium battery modules.

[0029] Therefore, another major objective of this invention is to provide a method for preparing aerogel fire-retardant and heat-insulating coatings, wherein such aerogel fire-retardant and heat-insulating coatings have strong adhesion to the surface of metal materials, do not age and degrade under prolonged sunlight, and exhibit excellent salt resistance and low moisture absorption in rainwater or aqueous solutions containing trace amounts of salt. These silicon-based aerogel fire-retardant and heat-insulating coatings are suitable for applications in automobiles and electric vehicles that require prolonged outdoor exposure. A further objective of this invention is to provide a method for preparing aerogel fire-retardant and heat-insulating coatings, wherein such aerogel fire-retardant and heat-insulating coatings combine highly fire-retardant coatings and highly heat-insulating aerogel particles, particularly suitable for preventing thermal runaway or heat dissipation from electric vehicle lithium battery modules. Spraying aerogel fire-retardant coatings onto the outer shell or chassis of electric vehicle lithium battery modules can prevent thermal runaway of the electric vehicle lithium battery module from causing high temperatures and heat to rapidly penetrate into the driver's compartment via the electric vehicle chassis, thereby increasing the safety of electric vehicle occupants.

[0030] In this invention, the condensation solution is first rapidly stirred and dispersed in a large amount of dispersion solution using suspension dispersion technology during the aerogel preparation process. Then, the silicon oxide suspension droplets in this suspension dispersion solution are gelled to form wet aerogel particles. Subsequently, a large amount of dispersion solution can be removed using filtration equipment or a solution discharge pipeline in the reaction tank to form silicon aerogel wet aerogel particles with a particle size ranging from tens of nanometers to tens of micrometers. After drying in the reaction tank with high-temperature gas at normal pressure, aerogel micron or nano particles with low thermal conductivity and high fire resistance can be prepared. Subsequently, the dried aerogel particles are further mixed in a mixing tank with a large amount of inorganic adhesive aqueous solution to ensure that the dried aerogel particles are uniformly dispersed in the inorganic adhesive aqueous solution. The product combined in this way will have the characteristics of aerogel fireproof coating with extremely strong adhesion to the surface of metal plates, high thermal insulation efficiency, high fire resistance, and no smoke under high-temperature flames.

[0031] The method provided by this invention can be used to prepare an aerogel fireproof coating that possesses strong adhesion to metal sheet surfaces, is smokeless and non-toxic under high-temperature flames, and exhibits high fire resistance and high heat insulation performance. It is particularly relevant for applications such as thermal runaway protection of lithium battery modules in electric vehicles, fireproof door metal panels or H-steel frame structures in buildings, or fireproof and heat insulation of the interior of high-speed aerospace vehicles. The method includes: a mixing and hydrolysis step (S1): adding a siloxane precursor to an aqueous ethanol solution and stirring to form a mixed solution. The siloxane precursor includes siloxane compounds and hydrophobic siloxane compounds with alkyl substituted of different chain lengths, or combinations thereof. Subsequently, an acid catalyst is added to the mixed solution to further... Hydrolysis reaction; Condensation dispersion step (S2): Add alkaline catalyst solution to the mixed solution and stir evenly to carry out condensation reaction to obtain condensation solution. Then, add a large amount of dispersion aqueous solution and quickly stir and disperse using a dispersion device such as an emulsifier or homogenizer to suspend and disperse the condensation solution in a large amount of dispersion aqueous solution. The dispersion solution includes suspended and dispersed submicron-sized condensation droplets formed by the condensation reaction and a large amount of dispersion aqueous solution. Then, continue stirring the dispersion solution to gel the suspended and dispersed submicron-sized condensation solution system to form surface-stable aerogel wet gel particles, and the aerogel wet gel particles are suspended and dispersed in a large amount of dispersion aqueous solution; Atmospheric pressure drying step (S2): 3): The surface-stable aerogel wet gel particles are suspended in an aqueous dispersion solution. The surface-stable aerogel wet gel particles are filtered using a filter. Subsequently, a high-temperature drying airflow at normal pressure is provided in a drying tank to rapidly vaporize the dispersion solvent contained in the surface-stable aerogel wet gel particles to obtain dried aerogel particles. Because the surface-stable aerogel wet gel particles contain a large number of hydrophobic alkyl structures of different chain lengths, the shrinkage and rupture of the aerogel structure caused by the interfacial tension of water molecules in the aerogel wet gel particles can be suppressed during the drying process. Combining the above techniques, dried aerogel particles with a porous structure and both low thermal conductivity and high fire resistance can be obtained quickly; High-temperature resistant adhesive mixing step (S4): Prepare adhesives that can withstand temperatures above 500℃. In the colloidal solution, the dried aerogel particles are added to the high-temperature resistant colloidal solution while being slowly stirred to disperse and impregnate the dried aerogel particles in the high-temperature resistant colloidal solution. In the mixing and dispersion step (S5), the high-temperature resistant colloidal solution impregnated with the dried aerogel particles is further mixed and dispersed using a stirring device. In this step, a wetting agent, a defoaming agent, and a dispersant may be added to the high-temperature resistant colloidal solution impregnated with the dried aerogel particles to ensure that the aerogel particles are completely and uniformly dispersed in the high-temperature resistant colloidal solution, thereby forming a uniform aerogel fireproof and heat-insulating coating. Through the above preparation steps, a silicon-based aerogel fireproof and heat-insulating coating that is smokeless, non-toxic, and has high fireproof and heat-insulating performance under high-temperature flames can be obtained.

[0032] Further, in the mixed hydrolysis step (S1), the siloxane compound comprises tetramethoxysilane (TMS), tetraethoxysilane (TES), or a combination thereof; the hydrophobically modified siloxane compound comprises one or a combination of alkyl-substituted hydrophobic siloxanes of different chain lengths, such as methyltrimethoxysilane (MTMS), propyltrimethoxysilane (PTMS), hexyltrimethoxysilane (HTMS), octyltrimethoxysilane (OTMS), and hexamethyldisilane (HMDS), wherein, in the siloxane precursor, the molar ratio of the siloxane compound to the hydrophobically modified siloxane compound is between (0:100 mol%) and (95:5 mol%). The purpose of adding hydrophobically modified siloxane compounds with different chain lengths (mol%) is to reduce the shrinkage and cracking of the aerogel structure during the drying process and to reduce the thermal conductivity. On the other hand, the purpose of adding the siloxane compound is to provide control over the internal microstructure of the aerogel structure and to increase the pore structure and porosity in the structure, so as to reduce the thermal conductivity or improve the fire resistance.

[0033] Furthermore, in the mixed hydrolysis step (S1), the higher the content ratio of the acid catalyst in the mixed solution, the faster the hydrolysis rate. However, the presence of a large number of acid ions will generate ionic conductivity under the action of an electric field, thus significantly increasing the dielectric constant and decreasing the dielectric strength of the aerogel structure. Conversely, the lower the content ratio of the acid catalyst, the slower the hydrolysis rate, and the significantly decreases the dielectric constant and increases the resistivity and dielectric strength of the aerogel structure. Therefore, this invention increases the hydrolysis rate of trace acid ions by reducing the acid catalyst content and increasing the process temperature, which can significantly reduce the content of added acid radical ions and condensed base ions in the overall system. On the other hand, siloxane compounds and hydrophobic siloxane compounds will generate a large number of alcohol molecules during the hydrolysis process. Therefore, deionized water is used to replace organic solvents such as ammonia and alkanes during the hydrolysis process, thereby reducing the addition of organic solvents such as ammonia and alkanes. In addition to reducing the influence of organic solvents such as ammonia on the dielectric properties of the aerogel, it can also reduce the hazards and environmental pollution of organic solvent treatment in the process, and reduce the overall preparation cost of the aerogel.

[0034] Furthermore, in the mixed hydrolysis step (S1), the higher the content of the alcohol-water solution in the overall mixed solution, the higher the porosity in the subsequently dried wet gel particles; conversely, the lower the content of the alcohol-water solution in the overall mixed solution, the lower the porosity in the subsequently dried wet gel particles; wherein the alcohol-water solution comprises ethanol, a recovered ethanol aqueous solution, a recovered methanol aqueous solution, recovered water, deionized water, filtered water, distilled water, or a combination thereof.

[0035] Further, in the condensation dispersion process (S2), an alkaline catalyst solution is added to the mixed hydrolysate solution and stirred until homogeneous to induce a condensation reaction. Then, a large amount of dispersion aqueous solution is added and rapidly dispersed using a dispersing device such as an emulsifier or homogenizer, causing the condensation solution to be suspended and dispersed in the large amount of dispersion aqueous solution. This dispersion solution includes suspended submicron-sized condensation droplets formed by the condensation reaction and a large amount of dispersion aqueous solution. The system is then continuously stirred until the suspended submicron-sized condensation droplets gel, forming surface-stable aerogel wet gel particles, which are suspended and dispersed in the large amount of dispersion aqueous solution. One of the main objectives of this step is to accelerate the gelation rate of the nano- to submicron-sized siloxane molecules or hydrophobic siloxane molecules in the large amount of dispersion aqueous solution, forming nano- to submicron-sized spherical molecular suspended wet gel particles. Another objective of this step is that the formed nano- to submicron-sized wet gel particles, due to their small particle size, significantly increase their specific surface area during subsequent drying, thus increasing the drying rate.

[0036] Furthermore, in the above-mentioned condensation dispersion step (S2), the aerogel wet gel particles with a particle size of nanometer to submicron contain a large number of hydrophobic siloxane molecules with different chain lengths alkyl-substituted. Due to the presence of these hydrophobic siloxane molecules with different chain lengths alkyl-substituted, the mixture of the siloxane compound and the hydrophobically modified siloxane compound can form an aerogel wet gel particle in the dispersion aqueous solution. This particle has a stable gelled hydrophobic surface and is uniformly dispersed in the dispersion aqueous solution. During the condensation dispersion process, the aerogel wet gel particles with a particle size of nanometer to submicron can form stable suspended particles in the dispersion aqueous solution without directly dissolving in the dispersion aqueous solution. Therefore, aerogel particles with a large porosity can be prepared without adding a large amount of hydrophobic organic solvents such as toluene or n-hexane, or without multiple replacement steps of hydrophobic organic solvents.

[0037] Further, the atmospheric pressure drying step (S3) includes: a vaporization step (S3-1): the dispersion aqueous solution system containing the surface-stable aerogel wet particles is filtered using a filter, and then a high-temperature drying airflow at atmospheric pressure is provided in the drying tank to rapidly vaporize the water and alcohol solvents in the surface-stable submicron aerogel wet particles. During the atmospheric pressure drying step, because the surface-stable aerogel wet particles contain a large number of hydrophobic alkyl structures of different chain lengths, the shrinkage and rupture of the aerogel structure caused by the interfacial tension of water molecules in the aerogel wet particles can be suppressed during the drying process. Therefore, through atmospheric pressure high-temperature airflow drying technology, porous dry aerogel particles with both low thermal conductivity and high fire resistance can be quickly obtained. Combining the reduction of aerogel particle size and the addition of a large number of hydrophobic alkyl structures of different chain lengths allows for the rapid drying of water molecules and alcohol molecules inside the aerogel structure. Generally, the large amount of mixed solvent in the aerogel wet particles is rapidly... The rapid azeotropic vaporization temperature is between 60 and 90°C; recovery step (S3-2): at this azeotropic vaporization temperature, the vaporized vapor of the mixed solvent is guided to a heat exchange recovery device; in the heat exchange recovery device, the mixed solvent is condensed and recovered, the purpose of which is to reduce costs and reduce environmental pollution; and the sudden boiling step (S3-3): the drying temperature of the dried aerogel particles is adjusted to a temperature above the sudden boiling temperature of the mixed solvent, and combined with microwave frequency rapid rotation to break the hydrogen bond of water molecules in the aerogel structure, and rapidly provide frictional heat to the solvent molecules, causing the remaining mixed solvent inside the near-dry aerogel to generate rapid sudden boiling and form positive pressure. This positive pressure inside the aerogel structure promotes the expansion behavior of the aerogel during the drying process, and causes the aerogel structure to generate a large number of nano- to sub-micron-sized micropores during the expansion process, so as to improve the porosity and thermal insulation properties of the aerogel product, wherein the sudden boiling temperature is between 110 and 180°C.

[0038] Furthermore, in the above-mentioned high-temperature resistant adhesive mixing step (S4), a high-temperature resistant colloidal solution capable of withstanding temperatures above 500°C is prepared. Under stirring conditions in a mixer, the dried aerogel particles are added to the stirring high-temperature resistant colloidal solution. In this step, a wetting agent, defoaming agent, and dispersant may be added simultaneously to disperse and impregnate the dried aerogel particles in the high-temperature resistant colloidal solution. The high-temperature resistant colloidal solution contains a high-temperature resistant adhesive material capable of withstanding temperatures above 500°C, which includes inorganic adhesive materials, organic adhesive materials, thermosetting resins, or any combination thereof. Specifically, the high-temperature resistant adhesive material comprises pure inorganic adhesive materials or a large amount of inorganic adhesive materials mixed with trace amounts of organic adhesive materials, for example, 75 to 97% v / v% inorganic adhesive materials mixed with 3 to 2% organic adhesive materials. 5v / v% organic thermosetting resin; furthermore, the inorganic adhesive material includes water glass, inorganic silicone resin, copper oxide-phosphate adhesive, silicate adhesive, phosphate-silicate adhesive, sulfate adhesive, magnesium oxide-silica-borax inorganic adhesive, or any combination thereof; in addition, the organic adhesive material includes polyimide, polyetherimide, polyphenylene ether, polyphenylene sulfide, polyetherketone liquid crystal polymer, polytetrafluoroethylene, polymelamine, polyphenolic resin, polymelamine-formaldehyde, high-temperature resistant silicone, silicone-modified polyurethane, silicone-modified acrylate, silicone-modified polyvinyl alcohol, and organic thermosetting resin including epoxy resin, organic high-temperature resistant silicone resin, and silicone-modified epoxy resin, or any combination thereof.

[0039] Furthermore, in the above-mentioned blending and dispersion step (S5), the high-temperature resistant colloidal solution containing the dry aerogel particles is further blended and dispersed using a stirring device. In this step, a wetting agent, a defoaming agent, and a dispersant may be added to ensure that the dry aerogel particles are completely and uniformly dispersed in the high-temperature resistant colloidal solution, thereby forming a uniform aerogel fireproof and heat-insulating coating. Through the above preparation steps, a silicon-based aerogel fireproof and heat-insulating coating that is smokeless, non-toxic, and has high fireproof and heat-insulating properties under high-temperature flames can be obtained. The present invention aims to provide a method for preparing aerogel fire-retardant and heat-insulating coatings, which improves upon the shortcomings of traditional aerogel organic coatings or thermally expanding metal oxide organic fire-retardant coatings, thereby producing coatings that possess excellent adhesion properties to metal or plastic sheets, as well as smokeless operation, high heat insulation efficiency, and high fire resistance under high-temperature flames. Another objective of the present invention is to provide a method for preparing aerogel fire-retardant and heat-insulating coatings, which improves upon the traditional method of applying aerogel inorganic fire-retardant coatings to fire doors or fire-resistant rolling doors, where the back of the iron plate of the fire door or fire-resistant rolling door can be significantly maintained below 500 degrees Celsius under high-temperature flame conditions of 850 to 1250°C for 1 to 3 hours. Furthermore, a further objective of the present invention is to provide a method for... This invention provides an aerogel fire-retardant and heat-insulating coating, suitable for the exterior of high-temperature smelting boiler structures or the heat insulation or fireproof insulation layer of high-speed aerospace vehicles. It can prevent heat loss from pipelines or machine platform interfaces, thereby improving energy saving and carbon reduction efficiency, or it can prevent high heat generated by air friction, thereby reducing damage to precision detection components inside high-speed aerospace vehicles. The aerogel fire-retardant and heat-insulating coating provided by this invention is particularly suitable for preventing thermal runaway or heat dissipation of electric vehicle lithium battery modules. Spraying the aerogel fire-retardant coating on the outer shell of the electric vehicle lithium battery module or the electric vehicle chassis can prevent the high temperature and heat caused by thermal runaway of the electric vehicle lithium battery module from rapidly penetrating into the driver's space through the electric vehicle chassis, thereby increasing the safety of electric vehicle occupants.

[0040] Furthermore, in the above preparation method, the aerogel fire-retardant coating, which exhibits smokeless and non-toxic properties as well as high fire resistance and high heat insulation performance under high-temperature flame conditions, contains dried aerogel particles with a porous structure, a porosity ranging from 50.0% to 75.0%, and a density ranging from 0.06% to 0.12 g / cm³. 3Its thermal conductivity ranges from 0.020 to 0.045 W / mK, its dielectric constant ranges from 1.30 to 1.85, and its flame retardancy is above UL94-V0. This aerogel fire-retardant and heat-insulating coating is further combined with a high-heat-resistant inorganic adhesive or an inorganic-organic mixed adhesive to form a highly heat-insulating and highly fire-resistant aerogel inorganic fire-retardant coating. When this highly heat-insulating and highly fire-resistant aerogel inorganic fire-retardant coating is sprayed onto the front of an aluminum plate to a thickness of 150 to 200 micrometers, after drying, it... When sprayed with a 200°C high-temperature flame for at least 5 minutes, the temperature of the back side of the aluminum plate relative to the front side is 300 to 350°C, so the aluminum plate will not burn through. In contrast, on another aluminum plate that is not coated with this high-heat-insulating and high-fire-retardant aerogel inorganic fire-retardant coating, the front side of the aluminum plate is melted through when sprayed with a 1200°C high-temperature flame for 1 minute, and the temperature of the back side reaches 950 to 1050°C, showing that the aerogel inorganic fire-retardant coating has excellent fire-resistant and heat-insulating properties.

[0041] The preparation method provided by this invention has the following advantages:

[0042] 1. The preparation method provided by this invention improves upon the shortcomings of traditional aerogel heat-insulating coatings and thermally expanding organic coatings in high-temperature fire resistance, and promotes the widespread application of aerogel heat-insulating materials. It prepares an aerogel fire-retardant coating that is smokeless, non-toxic, and has high fire resistance and heat insulation performance under high-temperature flames. The aerogel particles are prepared using a modified sol-gel suspension dispersion technology. The process does not involve the addition of large amounts of organic solvents, surfactants, and adhesives, eliminating the need for long-term solvent replacement and supercritical drying technology. Porous aerogel particles can be rapidly prepared using atmospheric pressure high-temperature airflow drying technology with solvent recovery. The overall process is simple, safe, and economical. The batch processing speed can be reduced to 4 to 10 hours to complete submicron-sized aerogel particle products. Furthermore, aerogel particles can be continuously produced using fluidized bed dynamic drying or high-temperature airflow drying technology to improve production efficiency.

[0043] 2. In the preparation method provided by the present invention, factors such as the ratio of siloxane compounds and hydrophobic siloxanes with different chain lengths substituted with alkyl groups, the content of hydrolysis solvent, the content of dispersion aqueous solution, the stirring rate of dispersion equipment such as emulsifiers or homogenizers, and the content and ratio of acid catalysts and alkali catalysts can be used to easily control the porosity, pore size, porosity between aerogel particles and the dense properties of the aerogel structure.

[0044] 3. In the preparation method provided by this invention, the repulsive force of hydrophilic-hydrophobic properties and rapid stirring are used to form nano- to micron-sized wet gel particles from siloxane compounds and hydrophobic siloxanes with different chain lengths substituted with alkyl groups, thereby improving the drying rate of wet gel particles and reducing shrinkage. Therefore, no other hydrophobic organic solvents other than alcohols are added, such as cyclohexane, benzene, isopropanol, ammonia, or a large amount of surfactants. The concentrations of acid catalysts and alkali catalysts are controlled at extremely low levels, which can further regulate the thermal conductivity, fire resistance, and dielectric properties of aerogel materials, thereby reducing the manufacturing cost of aerogel composite materials.

[0045] 4. The preparation method provided by this invention includes a rapid condensation dispersion solution technique using an emulsifier or homogenizer, followed by gelation of this condensation dispersion solution. This allows siloxane compounds and hydrophobic siloxane oil droplets with alkyl-substituted chains of different lengths to form stable hydrophobic aerogel wet particles in a large amount of dispersed aqueous solution. Furthermore, during the subsequent gelation process, the aerogel wet particles form a phase-separated structure due to hydrophilic-hydrophobic repulsion, further forming a network aerogel structure. The hydrophobic siloxanes with different alkyl-substituted chains of different lengths within the aerogel wet particles are distributed at the molecular level, giving the formed aerogel wet particles excellent hydrophobic properties. In the subsequent atmospheric pressure drying step, aerogel particles with different pore sizes can be prepared. Compared with other techniques, the products prepared using this technology not only save a large amount of organic solvents but also have a rapid processing speed.

[0046] 5. To address the shortcomings of traditional aerogel organic coatings, this invention not only improves upon previous aerogel manufacturing processes but also develops a high-temperature resistant colloidal solution formed by mixing inorganic adhesives or inorganic adhesives with organic adhesives in the formulation of aerogel fire-retardant coatings. This solution produces a high-temperature resistant adhesive that releases no smoke or odor when burned under a 1200°C flame, and it exhibits excellent bonding with various materials such as metals, ceramics, plastics, inorganic fibers, and organic fibers. Furthermore, the aerogel particles are mixed with the formulated high-temperature resistant adhesive, utilizing the properties of the aerogel particles... The porous structure of the particles achieves a heat insulation mechanism, while the high-temperature resistant colloidal solution achieves high-temperature resistance and fire resistance, thus forming an aerogel fire-retardant coating that is smokeless, non-toxic, and has high fire resistance and heat insulation performance under high-temperature flames. Based on this technology, aerogel fire-retardant coatings can be used to prevent thermal runaway or heat dissipation of electric vehicle lithium battery modules. Spraying aerogel fire-retardant coatings on the outer shell of electric vehicle lithium battery modules or the chassis of electric vehicles can prevent the high temperature and heat caused by thermal runaway of electric vehicle lithium battery modules from rapidly penetrating into the driver's space through the electric vehicle chassis, thereby increasing the safety of electric vehicle occupants.

[0047] 6. The preparation method provided by this invention can further improve the fireproof effect of traditional fire doors or fireproof rolling doors. When the aerogel fireproof coating is sprayed, after being sprayed with a high-temperature flame at 850 to 1250°C for 1 to 3 hours, the back of the iron plate of the fire door or fireproof rolling door can be significantly kept below 500°C. On the other hand, the aerogel fireproof coating prepared by the method provided by this invention is also suitable as a fireproof layer on the exterior of high-temperature smelting boiler structures, or as a heat insulation layer or heat insulation and fireproof layer on high-speed aerospace vehicles, to block the high heat generated by air friction and reduce the damage to the precision detection components inside the high-speed aerospace vehicles. The aerogel material contained in the above-mentioned aerogel fireproof coating has a porous structure with a porosity between 50.0% and 75.0% and a density between 0.06% and 0.12g / cm³. 3 Its thermal conductivity ranges from 0.020 to 0.045 W / mk, its dielectric constant ranges from 1.30 to 1.85, and its flame retardancy is above UL94-V0. The aforementioned aerogel material combines highly heat-resistant inorganic adhesives or inorganic-organic mixed adhesives to form a highly heat-insulating and fire-resistant aerogel inorganic fire-retardant coating. When sprayed onto the surface of an aluminum plate to a thickness of 150 to 200 micrometers and dried, the aerogel inorganic fire-retardant coating can withstand being burned at a high temperature of 1200°C for up to 30 minutes, while maintaining a back surface temperature of 300 to 350°C, protecting the aluminum plate from burn-through. In contrast, an uncoated aluminum plate melts through after being burned at a high temperature of 1200°C for 1 minute, demonstrating the excellent fire-resistant and heat-insulating properties of the aforementioned aerogel inorganic fire-retardant coating. Attached Figure Description

[0048] Figure 1 This is a flowchart illustrating the first embodiment of the preparation process of an aerogel fire-retardant coating that is smokeless, non-toxic, and has high fire resistance and high heat insulation performance under high-temperature flame conditions.

[0049] Figure 2 This is a photograph of the appearance of aerogel particles with high thermal insulation efficiency and low density prepared by the method according to the first embodiment of the present invention.

[0050] Figure 3 The scanning electron microscope (SEM) image of aerogel particles with high thermal insulation efficiency and low density prepared by the first embodiment of the present invention has a magnification of 10,000x.

[0051] Figure 4 This is a photograph of the appearance of an aerogel fire-retardant coating prepared according to the method of the first embodiment of the present invention, which has smokeless and non-toxic properties and high fire resistance and high heat insulation performance under high temperature flame.

[0052] Figure 5The image is a scanning electron microscope (SEM) image of the cross section of an aerogel fireproof coating that is smokeless, non-toxic, and has high fire resistance and high heat insulation performance under high temperature flame, prepared by the method of the first embodiment of the present invention. The magnification is 5,000 times.

[0053] Figure 6 The photo is used to show a typical aluminum plate with a thickness of 1mm at 1200. o Photos of the appearance of the product before and after being burned in a high-temperature flame (C).

[0054] Figure 7 The photograph is used to illustrate the application of an aluminum plate coated with an aerogel fire-retardant coating prepared according to the first embodiment of the method, which exhibits smokeless, non-toxic, high fire resistance, and high heat insulation properties under high-temperature flame conditions at 1200°C. o Photos of the appearance of the product before and after being burned in a high-temperature flame (C). Detailed Implementation

[0055] Please see Figure 1 This invention provides a first embodiment of a method for preparing an aerogel fire-retardant coating, which is formed by adding an inorganic adhesive solution or an inorganic / organic adhesive solution to aerogel particles of different particle sizes and hydrophilic / hydrophobic properties. This aerogel fire-retardant coating exhibits smokeless and non-toxic properties, as well as high fire resistance and high heat insulation performance under high-temperature flames. The steps include: a mixing and hydrolysis step (S1), a condensation and dispersion step (S2), an atmospheric pressure drying step (S3), a high-temperature resistant adhesive mixing step (S4), and a blending and dispersion step (S5), wherein:

[0056] Mixed hydrolysis step (S1): A siloxane precursor is added to an aqueous ethanol solution to form a mixed solution, wherein the siloxane precursor comprises a hydrophobically modified siloxane compound, a siloxane compound, or a combination thereof. Subsequently, an acid catalyst is added to the mixed solution to carry out a hydrolysis reaction. In some embodiments, the siloxane compound comprises tetramethoxysilane (TMS), tetraethoxysilane (TES), or any combination thereof. In these embodiments, the hydrophobically modified siloxane compound comprises methyltrimethoxysilane (MTMS), propyltrimethoxysilane (PTMS), hexyltrimethoxysilane (HTMS), octyltrimethoxysilane (OTMS), or hexamethyldisilane. Hydrophobic siloxanes with different chain lengths substituted with alkyl groups such as e, HMDS, etc., or any combination thereof; specifically, the purpose of adding the hydrophobically modified siloxane is to reduce the cracking phenomenon of the aerogel structure during the drying process, and the purpose of adding the siloxane compound is to regulate the internal microstructure of the aerogel structure to increase the porosity of the structure; in these embodiments, the total molar percentage of the siloxane compound and the hydrophobic siloxane molecules with different chain lengths substituted with alkyl groups in the overall mixed solution is between 0.5 mol% and 40 mol%, and the molar percentage of the ethanol aqueous solution is between 99.5 mol% and 60 mol%.

[0057] In this embodiment, the molar ratio of the siloxane compound and the hydrophobic siloxane compound with different chain lengths substituted with alkyl groups ranges from (0:100) to (95:5.0); in a preferred embodiment, the molar ratio of the siloxane compound and the hydrophobic siloxane compound with different chain lengths substituted with alkyl groups is 5:95; in the ethanol-water solution, the molar ratio of ethanol to water ranges from 0:100 to 50:50; in a preferred embodiment, the molar ratio of ethanol to water is 15:85.

[0058] In the mixed hydrolysis step (S1), a siloxane compound, hydrophobic siloxane compounds with different chain lengths and alkyl-substituted structures are thoroughly mixed with a large amount of an ethanol-water solution containing trace amounts of acid catalyst. During the mixing process, a hydrolysis reaction is carried out simultaneously. The ethanol-water solution containing trace amounts of acid catalyst includes a mixture of ethanol, deionized water, treated water, secondary treated water, or any combination thereof. The molar ratio of the total content of the siloxane compound and the hydrophobic siloxane compound with different chain lengths to the content of the acid catalyst is 1:0.01 to 1:0.0005. The higher the content of the acid catalyst in the mixed solution, the faster the hydrolysis rate. However, on the other hand, the higher the content of the acid catalyst, the greater the ion content in the overall aerogel structure, and the greater the dielectric loss of the aerogel. In a preferred embodiment, the molar ratio of the total content of the siloxane compound and the hydrophobic siloxane compound with different chain lengths and alkyl-substituted structures to the content of the acid catalyst is 1:0.0015.

[0059] Condensation-dispersion step (S2): An alkaline catalyst solution is added to the mixed solution and stirred until homogeneous to induce a condensation reaction and obtain a condensation solution. Then, a large amount of a dispersion aqueous solution is added to the condensation solution, and the solution is rapidly stirred and dispersed using a dispersing device such as an emulsifier or homogenizer. This suspends the condensation solution in the large amount of dispersion aqueous solution, allowing the hydrolyzed mixed siloxane compounds in the condensation solution to undergo a condensation reaction, forming sol droplets. These are submicron-sized condensation droplets suspended and dispersed in the dispersion aqueous solution. The system of this suspended, dispersed submicron-sized condensation solution is then continuously stirred until the submicron-sized condensation droplets gelle to form surface-stable aerogel wet particles, which are suspended and dispersed in the large amount of dispersion aqueous solution. The volume ratio of the dispersion aqueous solution to the ethanol aqueous solution is from 100:0 to 30:70. In a preferred embodiment, the volume ratio of the dispersion aqueous solution to the ethanol aqueous solution is 100:0.

[0060] In the condensation dispersion step, increasing the temperature helps to significantly shorten the condensation reaction time, that is, the gelation time of the aerogel is effectively shortened in this dispersion condensation step (S2); wherein, when the content equivalent ratio of the alkali catalyst to the acid catalyst is 1.0:1.0, the condensation reaction temperature is 20 to 55°C, and the condensation reaction time is 20 to 250 minutes; in some preferred embodiments, the condensation reaction temperature is 25°C, and the condensation reaction time is about 220 minutes; when the condensation reaction temperature is 50°C, the condensation reaction time is about 15 minutes.

[0061] In the condensation dispersion step, the present invention utilizes a large number of alkyl-substituted hydrophobic siloxane compounds of different chain lengths within the nano- to submicron-sized aerogel wet gel particles. Therefore, in the dispersion aqueous solution, the presence of these alkyl-substituted hydrophobic siloxane compounds allows the mixture of siloxane compounds and hydrophobically modified siloxane compounds to form a stable gelled hydrophobic surface layer. Furthermore, the initial structural size of the siloxane aerogel molecules and the alkyl-substituted hydrophobic siloxane molecules within the particles can be controlled to be 5 to 10 nm. These initial structures then stack to form aerogel wet gel molecules of 50 to 100 nm, which are interconnected to form a three-dimensional network structure. Therefore, during the condensation dispersion process, these nano- to submicron-sized aerogel wet gel particles... Stable suspended particles can be formed in the dispersion aqueous solution system without directly dissolving in the aqueous solution. Therefore, aerogel wet gel particles with high porosity can be prepared without adding a large amount of hydrophobic organic solvents such as toluene or n-hexane, or without eliminating multiple replacement steps of hydrophobic organic solvents. The volume ratio of the added siloxane compound or a mixture of alkyl-substituted hydrophobic siloxane compounds of different chain lengths to the dispersion aqueous solution is between (1.0:1.0) and (1.0:5.0). In some embodiments, the volume ratio is 1.0:1.0 and the condensation reaction time is 70 minutes. Preferably, the volume ratio is 1.0:3.0 and the condensation reaction time is 30 minutes. More preferably, the volume ratio is 1.0:1.5, the condensation reaction time is reduced to 55 minutes, and a high aerogel particle yield is achieved.

[0062] In some other embodiments, increasing the content of the alkaline catalyst also significantly shortens the condensation reaction time. Specifically, the equivalence ratio of 1.0M alkaline catalyst to 1.0M acid catalyst is (0.8:1.0) to (2.0:1.0), and the condensation reaction time is 360 to 3 minutes. Preferably, the equivalence ratio is 0.8:1.0, and the condensation reaction time is 360 minutes. More preferably, the equivalence ratio is 1.6:1.0, and the condensation reaction time is approximately 10 minutes. It should be further noted that when the equivalence ratio is less than 1.0:1.0, the condensation reaction time gradually increases, while the dielectric loss of the prepared aerogel decreases significantly. When the equivalence ratio is greater than 1.0:1.0, the condensation reaction time gradually decreases, but the dielectric loss of the prepared aerogel increases significantly due to the increased ion content. In a preferred embodiment of this practice, the volume ratio is 1.2:1.0.

[0063] Furthermore, the atmospheric pressure drying step (S3) includes a solvent vaporization step (S3-1), a solvent recovery step (S3-2), and a solvent boiling step (S3-3).

[0064] Atmospheric pressure drying step (S3): The dispersion aqueous solution system containing the surface-stable submicron aerogel wet gel particles is filtered out using a filter, leaving the submicron aerogel wet gel particles. Then, a high-temperature, atmospheric pressure drying airflow is provided in the drying tank to rapidly vaporize the residual water and alcohol solvents in the surface-stable submicron aerogel wet gel particles. During the atmospheric pressure drying step, because these submicron aerogel wet gel particles contain a large number of hydrophobic alkyl structures of different chain lengths, the shrinkage and rupture of the aerogel structure caused by the interfacial tension of water molecules in these submicron aerogel wet gel particles is suppressed during the drying process. Therefore, atmospheric pressure high-temperature airflow drying technology can quickly obtain porous aerogel particles with both low thermal conductivity and high fire resistance. Combining the reduction of aerogel particle size and the addition of a large number of hydrophobic alkyl structures of different chain lengths allows for the rapid drying of water molecules and alcohol molecules inside the aerogel structure. The rapid azeotropic vaporization temperature of the large amount of mixed solvents in the aerogel wet gel particles is between 60 and 90°C; preferably, the azeotropic vaporization temperature is 90°C.

[0065] Specifically, in the atmospheric pressure drying step, a solvent recovery device can be designed to perform a solvent recovery step (S3-2). The drying process is carried out in an atmospheric pressure high temperature gas flow. Under the azeotropic vaporization temperature environment, the vaporized vapor is guided to the heat exchange recovery device. In the heat exchange recovery device, the water-containing alcohol is condensed and recovered. The purpose of this recovery is to reduce costs and reduce environmental pollution.

[0066] Surge boiling step (S3-3): After most of the solvent in the wet aerogel particles vaporizes to obtain a dry aerogel structure, the temperature of the drying gas flow for the dry aerogel structure is adjusted to a temperature above the surge boiling temperature of the mixed solvent. Combined with rapid rotation at microwave frequency, this disrupts the hydrogen bonds of water molecules in the aerogel structure, providing frictional heat to the solvent molecules. This causes the remaining mixed solvent inside the dry aerogel structure to rapidly surge boiling, creating positive vapor pressure. This positive vapor pressure induces expansion of the dry aerogel structure during further drying, resulting in numerous nano- to sub-micron-sized micropores. This expansion produces dryer gel particles, specifically improving the porosity and thermal insulation properties of the dry aerogel particles and downstream products. Preferably, the surge boiling temperature is 110 to 180°C; more preferably, it is 150 to 180°C.

[0067] On the other hand, since no large amounts of organic solvents such as alkanes, aromatic benzenes, and amines, as well as surfactants, are added, the drying process is relatively safe and can produce aerogel products with higher purity. Because the high-porosity dried aerogel particles prepared do not contain any impurities, the thermal insulation properties, dielectric constant, and dielectric loss of the downstream products are all superior.

[0068] High-temperature resistant adhesive mixing step (S4): Prepare a high-temperature resistant colloidal solution that can withstand temperatures above 500°C. Under slow stirring conditions in a mixer, add the dried aerogel particles to the stirring high-temperature resistant colloidal solution, and continue stirring slowly to disperse and impregnate the dried aerogel particles in the high-temperature resistant colloidal solution. The high-temperature resistant colloidal solution contains a high-temperature adhesive material that can withstand temperatures above 500°C, including pure inorganic adhesive or inorganic adhesive mixed with trace amounts of organic adhesive. For example, the inorganic adhesive mixed with trace amounts of organic adhesive can be, for example, 75 to 97% v / v% of the inorganic adhesive mixed with 3% organic adhesive. Up to 25 v / v% organic hot-melt adhesive; in some embodiments, the inorganic adhesive comprises water glass, inorganic silicone resin, copper oxide-phosphate adhesive, silicate adhesive, inorganic silicone polymer adhesive, phosphate-silicate adhesive, sulfate adhesive, magnesium oxide-silica-borax inorganic adhesive, or any combination thereof; the organic adhesive comprises polyimide, polyetherimide, polyphenylene ether, polyphenylene sulfide, polyetherketone liquid crystal polymer, polytetrafluoroethylene, polymelamine, polyphenolic resin, polymelamine-formaldehyde, high-temperature resistant silicone, silicone-modified polyurethane, silicone-modified acrylate, organic The silicone-modified polyvinyl alcohol or organic thermosetting resin includes one or any combination of epoxy resin, organic high-temperature resistant silicone resin, and silicone-modified epoxy resin; the weight content of the dried aerogel particles in the aerogel fire-retardant coating as a whole is between 10.0 and 45.0 wt%, and the weight content of the high-temperature resistant colloidal solution is between 55.0 and 90 wt%; wherein, the lower the weight content of the high-temperature resistant colloidal solution, the lower the overall adhesion strength of the aerogel fire-retardant coating to metals, ceramics, and plastics, and the less effective the heat insulation of the prepared aerogel fire-retardant coating. The aerogel fire retardant coating exhibits superior properties. Conversely, the higher the weight content of the high-temperature resistant colloidal solution, the higher the adhesion strength of the aerogel fire retardant coating to metals, ceramics, and plastics. The prepared aerogel fire retardant coating also exhibits higher high-temperature fire resistance and better density, but its heat insulation properties are poor, and it shows obvious sagging when sprayed onto the substrate surface. Therefore, in order to optimize the formulation of the aerogel fire retardant coating so that it simultaneously possesses smokeless operation under high-temperature flames, high heat insulation efficiency, and high fire resistance, the weight content of the dried aerogel particles is preferably between 13.0 and 15.0 wt%.

[0069] Mixing and Dispersion Step (S5): The high-temperature resistant colloidal solution containing the dried aerogel particles is further mixed and dispersed using a stirring device. In this step, trace amounts of wetting agent, defoamer, and dispersant can be added to ensure the dried aerogel particles are completely and uniformly dispersed in the high-temperature resistant colloidal solution, forming a uniform aerogel fireproof and heat-insulating coating. Through the above preparation steps, a silicon-based aerogel fireproof and heat-insulating coating with smokeless and non-toxic properties, high fire resistance, and high heat insulation performance under high-temperature flames can be obtained. The main objective of this invention is to improve upon the shortcomings of traditional aerogel organic coatings or thermally expanding metal oxide organic fireproof coatings, to prepare an aerogel inorganic fireproof coating that possesses excellent adhesion properties to metal or plastic sheets, as well as smokeless, high heat insulation efficiency, and high fireproof performance under high-temperature flames. This aerogel inorganic fireproof coating can also be used to improve the severe deformation of iron plates caused by high-temperature flames on traditional fire doors or fireproof rolling doors. After the iron plate surface is sprayed with the aerogel inorganic fireproof coating, at temperatures between 850 and 1250°C... o Even after being exposed to a high-temperature flame (C) for 1 to 3 hours, the back of the fire door or fire-resistant rolling shutter plate can still clearly maintain a temperature of 500°C. o Below C; on the other hand, this aerogel inorganic fire-retardant coating is also suitable for the exterior of high-temperature smelting boiler structures or high-speed aerospace vehicles as a heat insulation layer or heat insulation and fireproof layer, to reduce heat loss in pipelines or machine platform interfaces, improve energy saving and carbon reduction efficiency, or to block high heat generated by air friction, so as to reduce damage to precision detection components inside high-speed aerospace vehicles; furthermore, this aerogel inorganic fire-retardant coating is particularly suitable for thermal runaway or heat dissipation prevention of electric vehicle lithium battery modules. Spraying aerogel fire-retardant coating on the outer shell of electric vehicle lithium battery modules or electric vehicle chassis can prevent the high temperature and heat caused by thermal runaway of electric vehicle lithium battery modules from rapidly penetrating into the driver's space through the electric vehicle chassis, thereby increasing the safety of electric vehicle occupants.

[0070] The following figures illustrate several embodiments to demonstrate the technical effects achieved by the method provided by this invention; please refer to... Figure 2 The first embodiment of the aerogel particles prepared by the method has a high thermal insulation efficiency and low density. The photos show that the prepared aerogel particles are white powders with excellent uniformity.

[0071] Please see Figure 3 The scanning electron microscope (SEM) image of the aerogel particles with high thermal insulation efficiency and low density prepared by the first embodiment of the present invention has a magnification of 10,000 times. Under electron microscope observation, its microstructure shows obvious spherical aerogel particles with a particle size of approximately 100 to 200 nm and the size of the aerogel particle aggregates is approximately between the submicron and ten micron scales.

[0072] Please see Figure 4The image shows the appearance of an aerogel fire-retardant coating prepared according to the first embodiment, which exhibits smokeless, non-toxic, high fire resistance, and high heat insulation performance under high-temperature flame conditions. Specifically, the prepared aerogel fire-retardant coating has a white, viscous appearance, and its color is also formulated into black or other colors using inorganic pigments. The aerogel fire-retardant coating contains submicron to ten-micron aerogel particles to provide high-temperature resistance and high heat insulation properties, and also contains high-temperature resistant adhesives to provide even higher temperature resistance, high adhesion strength, and high fire resistance properties. The above combination forms an aerogel fire-retardant coating that exhibits smokeless, non-toxic, high fire resistance, and high heat insulation performance under high-temperature flame conditions, thereby enhancing the application fields of aerogel.

[0073] Please see Figure 5 The image is a cross-sectional scanning electron microscope (SEM) image of an aerogel fireproof coating film prepared according to the first embodiment sample preparation method, which has smokeless and non-toxic properties as well as high fire resistance and high heat insulation performance under high temperature flame, with a magnification of 5,000 times. Figure 5 As shown, in this embodiment, the interior of the aerogel fire-retardant coating is a composite material in which a high-temperature resistant adhesive encapsulates submicron to ten-micron-sized aerogel aggregates. Specifically, a large number of submicron-sized aerogel molecules are dispersed in the high-temperature resistant adhesive. Furthermore, in the cross-section of the aerogel fire-retardant coating, it can be clearly seen that the aerogel molecule aggregates in the high-temperature resistant adhesive still contain a large number of pores. Therefore, in the cross-sectional structure of the overall aerogel fire-retardant coating film, the large number of aerogel molecules and pores provide the aerogel fire-retardant coating with low heat transfer and high heat insulation properties.

[0074] Please see Figure 6 It is a 1mm thick ordinary aluminum plate at 1200 o Photos of the appearance before and after high-temperature flame burning at 1200°C. o During the high-temperature flame burning process, the temperature on the back of the aluminum plate reaches approximately 600°C within 50 seconds. o C, while aluminum plates are at 1200 o It was burned through in about one minute under the high temperature of the flame. Figure 6 As shown on the right.

[0075] Please see Figure 7 An aluminum plate coated with an aerogel fire-retardant coating prepared according to the method of the first embodiment, which exhibits smokeless, non-toxic, high fire resistance, and high heat insulation properties under high-temperature flame conditions, was subjected to a temperature of 1200°C. o C. Appearance photos before and after high-temperature flame spraying; specifically, the aerogel fire-retardant coating is approximately 150μm thick, and the images show the temperature of the back side of the aluminum plate during flame spraying, which is approximately 350°C. o C, while aluminum plates are at 1200 o Even after being burned by a high-temperature flame for 30 minutes, there was still no burn-through. Figure 7 As shown on the right. This demonstrates that aerogel fire-retardant coatings, which are smokeless, non-toxic, and possess high fire resistance and heat insulation properties under high-temperature flames, do indeed have excellent fire-resistant and heat-insulating effects, and can be applied to the prevention of thermal runaway in lithium battery modules for electric vehicles.

[0076] In summary, the manufacturing, application, and effects of the present invention have been clearly disclosed. However, the above-described embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of patent protection of the present invention. That is, simple equivalent changes and modifications made in accordance with the scope of patent protection and the description of the invention fall within the scope of patent protection of the present invention.

[0077] [Symbol Explanation]

[0078] (S1) Mixed hydrolysis steps

[0079] (S2) Condensation-dispersion step

[0080] (S3) Atmospheric pressure drying step

[0081] (S4) High-temperature adhesive mixing steps

[0082] (S5) Blending and Dispersing Steps

[0083] (S3-1) Solvent vaporization step

[0084] (S3-2) Solvent recovery step

[0085] (S3-3) Solvent Boiling Step

Claims

1. A method for preparing an aerogel fire-retardant and heat-insulating coating, characterized in that, Formed by adding inorganic adhesive solution or one of inorganic / organic adhesive solution using aerogel particles of different particle sizes and hydrophilic / hydrophobic properties, comprising the following steps: Mixed hydrolysis step: A siloxane precursor is added to an aqueous ethanol solution to form a mixed solution, wherein the siloxane precursor includes alkyl hydrophobically modified siloxane compounds of different chain lengths, siloxane compounds or combinations thereof, and then an acid catalyst is added to the mixed solution to carry out the hydrolysis reaction; Condensation and dispersion step: An alkaline catalyst solution is added to the mixed solution to carry out a condensation reaction to obtain a condensation solution. Then, a dispersion aqueous solution is added to the condensation solution and the mixture is rapidly stirred with an emulsifier or homogenizer to condense the hydrolyzed mixed siloxane compounds in the condensation solution to form sol oil droplets, which are suspended and dispersed in the dispersion aqueous solution. Subsequently, the sol oil droplets condense to form an aerogel wet gel particle with a stable hydrophobic shell and uniformly dispersed in the dispersion aqueous solution. Atmospheric pressure drying step: The dispersed aqueous solution is filtered out by a filter at atmospheric pressure and drying temperature to obtain the aerogel wet gel particles. Then, a high-temperature drying airflow at atmospheric pressure is provided to cause the solvent contained in the aerogel wet gel particles to vaporize rapidly to obtain dried aerogel particles. The drying temperature is between 60 and 150°C. High-temperature resistant adhesive mixing steps: Prepare a high-temperature resistant colloidal solution and slowly stir it. Add the dried aerogel particles to the solution while slowly stirring to disperse and impregnate the particles. The high-temperature resistant colloidal solution must be able to withstand temperatures of at least 500°C. Mixing and dispersing step: The high-temperature resistant colloidal solution containing the dried aerogel particles is mixed and dispersed using a mixer, and a wetting agent, defoamer and dispersant are added to the high-temperature resistant colloidal solution containing the dried aerogel particles to make the dried aerogel particles completely and uniformly dispersed in the high-temperature resistant colloidal solution to form an aerogel fireproof and heat-insulating coating, which has the properties of being smokeless and non-toxic, and having high fire resistance and high heat insulation under high temperature flames.

2. The preparation method according to claim 1, characterized in that, This aerogel fireproof and heat-insulating coating improves upon the shortcomings of traditional aerogel organic coatings or thermally expanding metal oxide organic fireproof coatings. It combines excellent adhesion to metal or plastic sheets with smokeless, non-toxic, highly fireproof, and highly heat-insulating properties under high-temperature flames. This aerogel fireproof and heat-insulating coating is suitable for preventing thermal runaway or heat dissipation of lithium battery modules in electric vehicles. By spraying the aerogel fireproof coating on the outer shell of the lithium battery module or the chassis of the electric vehicle, the high temperature and heat caused by thermal runaway of the lithium battery module can be quickly conducted through the chassis of the electric vehicle and seep into the driver's space, thereby increasing the safety of the electric vehicle occupants.

3. The preparation method according to claim 1, characterized in that, This atmospheric pressure drying step includes: Vaporization step: The solvent in the structure of the aerogel wet gel particles is rapidly azeotropically vaporized at an azeotropic vaporization temperature to distill and dry the solvent and obtain a dry aerogel structure, wherein the azeotropic vaporization temperature is 60 to 90°C. Recovery steps: The azeotropic vapor of the solvent is directed to a heat exchange recovery device to promote solvent condensation and recovery; and Boiling step: Adjust the drying temperature to the boiling point to cause the solvent and water molecules contained in the dried aerogel structure to boil rapidly and generate positive vapor pressure to suppress the drying shrinkage of the dried aerogel structure and generate a large number of micropores, so as to obtain the dried aerogel particles with high heat insulation effect. The boiling point is 110 to 180°C.

4. The preparation method according to claim 1, characterized in that, The high-temperature resistant colloidal solution contains pure inorganic adhesive material or inorganic adhesive material mixed with organic adhesive material, wherein the inorganic adhesive material mixed with organic adhesive material includes 75 to 97 v / v% inorganic adhesive material and 3 to 25 v / v% organic adhesive material. The inorganic adhesive material includes water glass, inorganic silicone resin, copper oxide-phosphate adhesive, silicate adhesive, inorganic silicone polymer adhesive, phosphate-silicate adhesive, sulfate adhesive, magnesium oxide-silica-borax inorganic adhesive, or any combination thereof; The organic adhesive material comprises polyimide, polyetherimide, polyphenylene ether, polyphenylene sulfide, polyetherketone liquid crystal polymer, polytetrafluoroethylene, polymelamine, polyphenolic resin, polymelamine-formaldehyde, high-temperature resistant silicone, silicone-modified polyurethane, silicone-modified acrylate, silicone-modified polyvinyl alcohol, and organic thermosetting resin selected from the group consisting of epoxy resin, organic high-temperature resistant silicone resin and silicone-modified epoxy resin, or any combination thereof.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The siloxane compound comprises tetramethoxysilane, tetraethoxysilane, or combinations thereof; the hydrophobically modified siloxane compound comprises methyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, hexamethyldisilazane, or any combination thereof, wherein, in the siloxane precursor, the molar ratio of the siloxane compound and the hydrophobically modified siloxane compound with different chain lengths alkyl substitution is between (0:100 mol%) and (95:5.0 mol%).

6. The preparation method according to any one of claims 1 to 4, characterized in that, The blending and dispersion step includes blending and dispersing the high-temperature resistant colloidal solution impregnated with the dried aerogel particles using a stirring and dispersing device.

7. The preparation method according to any one of claims 1 to 4, characterized in that, In the overall case of this aerogel fireproof and heat-insulating coating, the weight percentage of the dried aerogel particles is between 10.0 and 45.0 wt%, and the weight percentage of the high-temperature resistant colloidal solution is between 55.0 and 90 wt%. The lower the weight percentage of the high-temperature resistant colloidal solution, the lower the adhesion strength of the aerogel fireproof and heat-insulating coating to metals, ceramics, or plastics, and the better its heat insulation properties. Conversely, the higher the weight percentage of the high-temperature resistant colloidal solution, the higher the adhesion strength of the aerogel fireproof and heat-insulating coating to metals, ceramics, and plastics, the higher its high-temperature fireproof performance and the better its density, but the heat insulation properties are poor, and there is obvious sagging phenomenon when sprayed on the substrate.

8. The preparation method according to any one of claims 1 to 4, characterized in that, The dried aerogel particles contained within this aerogel fire-retardant and heat-insulating coating have a porous structure with a porosity ranging from 50.0% to 75.0% and a density ranging from 0.06% to 0.12 g / cm³. 3 Its thermal conductivity ranges from 0.020 to 0.045 W / mk, its dielectric constant ranges from 1.30 to 1.85, and its flame retardancy is above UL94-V0; The aerogel fireproof and heat-insulating coating is further combined with high-heat-resistant inorganic adhesive or inorganic-organic mixed adhesive to form a highly heat-insulating and highly fire-resistant aerogel inorganic fireproof coating. When the highly heat-insulating and highly fire-resistant aerogel inorganic fireproof coating is sprayed onto the front of an aluminum plate to a thickness of 150 micrometers, after drying, it is burned at a high temperature of 1200°C for 30 minutes. The temperature of the back of the aluminum plate relative to the front is 300 to 350°C, and the aluminum plate will not be burned through. In contrast, on another aluminum plate that is not coated with the highly heat-insulating and highly fire-resistant aerogel fireproof coating, the front of the plate is burned through after about 1 minute of burning at a high temperature of 1200°C.

9. The preparation method according to any one of claims 1 to 4, characterized in that, This aerogel fireproof and heat-insulating coating is used to prevent thermal runaway or heat loss from lithium battery modules in electric vehicles. This aerogel fireproof and heat-insulating coating is used to reduce the severe deformation of iron plates caused by high temperature difference when fire doors or fireproof rolling doors are exposed to flames at 850 to 1250°C for 1 to 3 hours. This aerogel fireproof and heat-insulating coating is used on the exterior of high-temperature smelting boiler structures or as a heat insulation or heat-insulating and fireproof layer on high-speed aerospace vehicles. It is used to reduce heat loss in pipelines or machine platform interfaces, improve energy saving and carbon reduction efficiency, or to block high heat generated by air friction, thereby reducing damage to precision detection components inside high-speed aerospace vehicles.

10. An aerogel fire-retardant and heat-insulating coating, prepared using the preparation method according to any one of claims 1 to 9, characterized in that, Aerogel particles of different sizes and hydrophilicity / hydrophobicity are formed by adding an inorganic adhesive solution or an inorganic / organic adhesive solution, wherein the inorganic adhesive includes water glass, inorganic silicone resin, copper oxide-phosphate adhesive, silicate adhesive, inorganic silicone polymer adhesive, phosphate-silicate adhesive, sulfate adhesive, magnesium oxide-silica-borax inorganic adhesive, or any combination thereof. The organic adhesive comprises polyimide, polyetherimide, polyphenylene ether, polyphenylene sulfide, polyetherketone liquid crystal polymer, polytetrafluoroethylene, polymelamine, polyphenolic resin, polymelamine-formaldehyde, high-temperature resistant silicone, silicone-modified polyurethane, silicone-modified acrylate, silicone-modified polyvinyl alcohol, and organic thermosetting resin selected from the group consisting of epoxy resin, organic high-temperature resistant silicone resin and silicone-modified epoxy resin, or any combination thereof.

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