JP7575125B1 - Thermal insulation composite material comprising aerogel coated with heat-resistant material and its preparation method - Google Patents

Abstract

The present invention provides a thermal insulation composite material and a preparation method thereof, which is made by coating an aerogel with a heat-resistant outer layer having low dielectric constant, high thermal insulation, and high fire protection performance. The preparation method of the composite material includes a mixing hydrolysis step (1), a condensation and dispersion step (2), a structure formation step (3), a normal pressure drying step (4), an outer layer coating step (5), a hardening molding step (6), and a surface treatment step (7). During the condensation and dispersion, the aerogel melts into a heat-resistant gel that disperses by adding a small amount of water. The aerogel is then injected into a preformed structure containing fibers, and after normal pressure high temperature drying, the heat-resistant material is coated and hardened to prepare an aerogel composite material. The heat-resistant outer layer includes a single layer, a multilayer, or a multilayer laminate, and the product can be applied to fire prevention, energy saving, and carbon emission reduction, especially for thermal runaway safety protection of clean rooms or lithium battery modules in electric vehicles. [Selected Figure] Figure 1

Description

The present invention relates to the field of coating aerogel with heat-resistant materials, and more specifically to an aerogel composite material that is dust-free, has high thermal insulation, high fire resistance, and a low dielectric constant, and to a method for preparing the same.

As is well known, aerogel is a porous material with a three-dimensional network structure, with a porosity of 80% or more (even 95% or more), low density (about 0.005-0.2 g/cm ³ ), high specific surface area (500-2000 m ² /g), low thermal conductivity (k=15-40 mW/mk), low dielectric constant (Dk=1.3-2.0), low dielectric loss (Df<0.003 or less), etc., and aerogel or its composite material has excellent properties such as high thermal insulation, high fire resistance, and low dielectric constant. Aerogel or its composite material has high porosity and extremely low density, so it has great potential for applications such as high thermal insulation, high fire resistance, low signal transmission resistance, and high voltage resistance. Therefore, it is expected to gain a strategic position in various industries in the future, such as applications requiring heat resistance and fire protection, energy saving and carbon emission reduction, such as energy-intensive production equipment and transmission pipelines. At present, general organic foaming materials have a good thermal insulation effect at room temperature or below 120 degrees, but the preparation process of these organic foaming materials has already caused environmental pollution, and when the products are used in a temperature environment of 120 degrees or higher, they are decomposed quickly and lose their thermal insulation effect, limiting the application of organic foaming materials in environments of 120 degrees or higher. In addition, general inorganic fiber insulation products can be used for high-temperature insulation, but they do not have good properties for isolating from heat sources for a long time. Therefore, in the future, when applied to energy conservation and carbon emission reduction, it is necessary to replace the conventional organic foaming materials and inorganic fiber insulation products with better aerogels or related composite materials to improve the thermal insulation efficiency and energy utilization rate, improve the energy conservation and carbon emission reduction effects, and reduce the carbon emissions in the product process. In addition, in the future, high-frequency applications such as high-speed data transmission equipment such as 5G and 6G and high-speed transmission of signals for electric self-driving cars, a dielectric material with low dielectric constant (D _k <2.5), low dielectric loss (D _f <0.003), and high voltage resistance is also required. As can be seen from basic material theory, the porosity inside the material significantly reduces the transmission of thermal energy and holes, so the higher the porosity of the material structure, the higher its dielectric properties. Therefore, submicron and nanometer porous silicon dioxide aerogel materials can be used not only to prevent heat dissipation, but also in high-speed data transmission equipment such as 5G and 6G. Porous silicon dioxide aerogel significantly reduces the dielectric constant and dielectric loss, so it can also be used at the signal transmitting and receiving ends to improve signal transmission efficiency and reduce signal loss. In the future, it will be valuable for application in self-driving cars and aerospace vehicles.

However, although aerogel materials have the above excellent thermal insulation and dielectric effects, they have weak van der Waals forces between the molecules inside the material, so that aerogel-related products are very easy to shed dust, making them unsuitable for application in strict environments such as clean rooms. In response to this, the present invention team has been developing aerogel-related products with the aim of applying them to materials that save energy and reduce carbon emissions in clean room processes, and to high-temperature insulation materials for high-speed transmission in electric vehicles and thermal runaway in lithium batteries, and has continued to make unremitting efforts with the goal of preventing the spread of aerogel nanodust and the harm caused by dust falling. Currently, even if coating technology is added to various aerogel materials described in patents already disclosed internationally, it is not possible to completely prevent nanometer-class aerogel dust from leaking out, and especially at high temperatures of 200 degrees or more, the organic coating materials (e.g., polypropylene, polyester, polyimide, and fluoropolymer films) used in the currently disclosed technology are gradually fatigued and deteriorated when exposed to heat for a long time in a high-temperature environment, ultimately causing serious phenomena such as aerogel dust leaking out and dust falling. These phenomena remain important problems to be solved for high-temperature insulating materials in clean rooms and lithium batteries for electric vehicles.

The traditional method for preparing aerogel is the sol-gel synthesis method, which mainly involves first mixing precursors such as alkoxysilane, tetramethoxysilane, or water glass with a large amount of organic mixed solvent, and then adding an acid catalyst to cause hydrolysis. After the hydrolysis reaction is allowed to occur for a certain period of time, an alkali catalyst is added to cause condensation, and a sol is gradually formed during the condensation reaction process. The molecules in the sol continuously react and bond to gradually form a semi-solid polymer gel. Then, aging is performed for a certain period of time to make the gel form a three-dimensional network structure with a stable structure. Finally, the solvent is replaced using hydrophobic modified solvents such as 1-butanol, 1-hexanol, n-hexane, or cyclohexane, and the solvent in the aerogel structure is extracted and dried using supercritical drying technology. In addition to consuming a large amount of expensive organic solvents and supercritical equipment, the traditional process technology requires a long time to replace the solvent using hydrophobic modified solvents, which makes the preparation of aerogel very costly and time-consuming.

On the other hand, the preparation method of hydrophobically modified aerogel also adopts the sol-gel synthesis method, which mainly involves first mixing methylalkoxysilane precursors such as methyltrimethoxysilane (MTMS) and methyltriethoxysilane (MTES) with an organic solvent, and then adding an alkali catalyst to generate a hydrolysis reaction. After a certain period of hydrolysis, a condensation reaction is generated, and a sol is gradually formed during the condensation reaction process. The molecules in the sol continuously react and bond to gradually form a semi-solid polymer gel. After a certain period of aging, the solvent is replaced with isopropanol, acetone, n-hexane, or cyclohexane for 2 to 3 days to form a three-dimensional network structure with a stable structure in the hydrophobically modified gel. Finally, the solvent in the aerogel structure is dried by normal pressure drying technology to obtain a porous and dry aerogel block material. The process of hydrophobically modified aerogels requires the consumption of large amounts of expensive organic solvents and the need for lengthy solvent replacement with alcohols or alkanes, making preparation time-consuming and expensive.

All the process technologies used in the above-mentioned aerogel preparation methods use a large amount of hydrophobic modified solvent. For example, for organic solvents such as alkanes, the solvent is replaced multiple times for 2 to 3 days, and supercritical drying technology or normal pressure high temperature drying technology is used to avoid the situation where the aerogel structure shrinks or cracks due to the surface tension of water molecules during the normal pressure drying process. "Supercritical drying" is a process in which water and an organic solvent are brought to a supercritical state at high temperature and pressure, and the organic solvent and water simultaneously have gas-liquid mixing properties, and the solvent is directly evaporated and dried in the supercritical state. In this way, the excess solvent in the network structure is removed under supercritical conditions, and the wet gel does not shrink. However, the use of hydrophobic modified solvent replacement technology and supercritical drying technology multiple times during the related process takes time and increases costs, which may cause a loss of competitiveness in mass production and future applications of aerogel. The above-mentioned hydrophobic modification uses a multi-stage solvent replacement technique at room temperature and pressure, but this modification technique needs to be carried out for more than 24 hours, which is too long a process and not cost-effective.

In conventional patent documents, for example, Patent Document 1 below discloses "thermal insulation and heating component". The above invention provides a thermal insulation and a heating component. The thermal insulation includes a thermal insulation material and a first coated thermal insulation material, and a first coating layer is sewn along the first seam position to seal the thermal insulation material. The above-mentioned thermal insulation can prevent the scattering of dust generated by the thermal insulation material. In addition, a heating component including the above-mentioned thermal insulation is further provided. However, since the particle size of the aerogel dust is extremely small, the aerogel material is coated using one of a coating layer selected from silica gel, copper alkane lubricating oil, non-soap-based synthetic lubricating oil, lithium-based pressure-resistant oil, silicon-based oil, and molybdenum disulfide butter, and the coating layer is sewn using a seam. Although the dispersion of aerogel dust can be reduced, it is still not possible to completely suppress the leakage of aerogel dust of submicron or less so as to prevent the inside of the clean room from being contaminated.

For example, Patent Document 2 below discloses "Flexible composite aerogel and its manufacturing method." The invention relates to a method for directly dispersing and preparing a hydrophilic aerogel. This method comprises the step of forming a flexible composite organic aerogel, which comprises a textile reinforcement and disposing the organic aerogel in the textile reinforcement. The organic aerogel is based on a resin at least partially produced by polyphenol and formaldehyde, and is a polymerized organic gel containing at least one water-soluble cationic polyelectrolyte, or is a pyrolysis product of the gel having a porous carbon monoblock form and contains at least one pyrolysis product of the water-soluble cationic polyelectrolyte.

Also, for example, the following Patent Document 3 discloses "Aerogel Composite and Method for Preparing the Aerogel Composite". The invention relates to an aerogel composite. The aerogel composite includes at least one base layer having an upper surface and a lower surface, the base layer includes an augmented aerogel composition, and the aerogel composition includes an augmented material and a monoblock aerogel frame. A first mask layer includes a first mask material adhered to the upper surface of the base layer, and a second mask layer includes a second mask material adhered to the lower surface of the base layer. At least a portion of the monoblock aerogel frame of the base layer is stretched to enter a portion of the first mask layer and the second mask layer. The first mask material and the second mask material each include an elastic fiber such as spandex, nylon, lycra, elastic fiber, or a combination thereof, or are composed mainly of an elastic fiber. However, the aerogel coating material prepared contains elastic fibers or flexible polymer sheet films, and the adhesive materials used are organic adhesives such as acrylic esters, ethyl carbamates, and hot melt adhesives, and the related flexible products have a high degree of protection against aerogel.

For example, Patent Document 4 below discloses "Aerogel composite and preparation method thereof". The invention relates to a wet fiber material containing at least one of inorganic fibers and organic fibers. The wet fiber material and spacer are wound in a winding structure, or the wet fiber material and spacer are laminated in a planar form. The fiber material is loaded into a container. A precursor is injected into the container, and the precursor is gelled while removing residual air bubbles under vacuum to prepare a gel-fiber composite. The aerogel-fiber composite is removed from the container, and the spacer is removed. The gel-fiber composite is modified with an organic surface by using a solvent instead, and then the gel-fiber composite modified with the organic surface is dried at atmospheric pressure or supercritically.

For example, Patent Document 5 below discloses a "laminate comprising a reinforced aerogel composite material." The invention relates to an aerogel composite material. The aerogel composite material includes at least one base layer having a top surface and a bottom surface, the base layer including a reinforced aerogel composition and a monoblock reinforced aerogel frame, the composition including a reinforcement material, a first side layer including a first side material bonded to the top surface of the base layer, and a second side layer including a second side material bonded to the bottom surface of the base layer. At least a portion of the monoblock aerogel frame of the base layer both extends to at least a portion of the first side layer and the second side layer. The first side material and the second side material are each essentially composed of a fluoropolymer material.

For example, Patent Document 6 below discloses a "method for producing aerogel felt." The above invention relates to a method for producing aerogel felt, in which an aerogel slurry is first injected into glass fiber felt, and a layer of a sealing coating layer is formed on the surface of the glass fiber felt using a dipping liquid, thereby preventing dust from falling during storage, transportation, and use of the aerogel felt. This prevents the amount of aerogel in the aerogel felt from decreasing, and prevents the heat retention performance of the aerogel felt from being affected. The sealing coating layer on the surface is a mixture of acrylic emulsion, talc powder, VAE emulsion, and aqueous hardener.

The inventors have also disclosed in the following Patent Document 7 "Nonwoven fabric/aerogel composite fireproof/insulating material and its manufacturing method". In the above invention, after preparing aerogel through a hydrolysis step and a condensation step, the above-mentioned aerogel is added to the nonwoven fabric in a molding step, and the above-mentioned aerogel is fully inserted into the nonwoven fabric, and a nonwoven fabric/aerogel composite fireproof/insulating material is formed through a drying step, and the aerogel is fully inserted into the nonwoven fabric by an impregnation processing method or a continuous rolling method. The conditions for the above drying step are to dry the anhydrous aerogel at room temperature and pressure, or to dry by rapidly evaporating an organic solution at 30 to 80 degrees Celsius.

The inventors also disclosed a method for producing an aerogel/composite nonwoven fabric fireproof insulation material in the following Patent Document 7. In the above invention, a condensed solution of an aerogel solution of an ungelled silica gel-silica aerogel-silane coupling agent is formed through a mixing step, a hydrolysis step, and a condensation step, and then in a molding step, the condensed solution of the aerogel solution of the ungelled silica gel-silica aerogel-silane coupling agent is impregnated, sprayed, sprayed, or continuously sucked into a recycled composite nonwoven blanket or a general nonwoven blanket, and the aerogel of the silica gel-silica aerogel-silane coupling agent is gelled and inserted into the nonwoven blanket, and an aerogel/composite nonwoven fabric fireproof insulation material is formed through a drying step. The drying step is performed by drying the aerogel at room temperature and normal pressure, or performing a high-speed evaporation drying step of the organic solution at 30 to 80 degrees Celsius. The nonwoven fabric is made of one or a combination of polyethylene (PE), polypropylene (PP), polyester, polyamine, glass fiber, ceramic fibers, and carbon fiber to produce an aerogel composite material that is less likely to shed dust.

The above-mentioned invention patents are all related to the manufacturing technology of aerogel composite fiber blankets or insulation materials, whether they adopt direct preparation methods, different organic slurry soaking methods, or organic gel material adhesion methods. The team uses the prior art soft silica gel co-mixing method, which still has the disadvantage that aerogel fine dust is easy to fall off from the aerogel fiber composite blanket. Because the aerogel composite fiber blanket is easy to fall off dust, the heat resistance effect and insulation performance of the aerogel will gradually decrease, especially at high temperatures above 180 degrees. The organic aerogel, organic coating material, organic modifier, or organic adhesive used in the above-mentioned invention patents will fatigue and decompose quickly under the process conditions of 180-200 degrees, which will reduce the coating effect and cause a large amount of organic fine particles and aerogel dust to leak out.

The above organic materials leak aerogel dust due to fatigue and decomposition caused by high temperatures, causing pollution in high-tech industrial applications such as clean rooms and the interior of electric vehicles. This is the biggest drawback of aerogel insulation materials. The cause of serious dust leakage from aerogel or its composite materials is that there is a weak interaction between the internal aerogel molecules, which condense and aggregate to form a three-dimensional net-like porous structure, making it very easy for silica aerogel or organic-inorganic composite materials to generate nanometer to micrometer aerogel dust during application at high temperatures. This aerogel dust is the main reason why aerogel cannot be applied to high-tech industries in the near future. In particular, since the precision processes of high-tech industries are mainly carried out inside clean rooms, the pollution of high-tech industries and clean rooms by aerogel dust is the main reason or problem that prevents the application of high-insulation aerogel energy-saving materials to high-tech industrial production lines.

The inventors believe that the above-mentioned aerogel dust poses some drawbacks in terms of practical applications, and after extensive research, have come up with the present invention, which effectively improves the above-mentioned issues through rational design. The main object of the present invention is to provide a method for producing a composite material in which silica aerogel is coated with an inorganic material that combines high strength, high processability, high fire resistance, high thermal insulation, and antistatic properties.

Therefore, the current products that use polyester or polyimide organic films to cover aerogel are easily fatigued and decomposed during long-term application, and the defects of aerogel dust leakage are improved. The object of the present invention is to provide a composite material that combines high strength, high fire resistance, high insulation, and low dielectric constant, and avoids dust leakage, and that covers silica aerogel with a fiber-reinforced plastic (LFRP) inorganic material. The product of the present invention combines properties such as high strength, high hardness, high insulation, and high fire resistance, and can be applied to high-temperature processes in clean rooms and safety protection against thermal runaway of lithium battery modules in electric vehicles. Another object of the present invention is to provide an improved aerogel composite preparation technology for preparing an aerogel structure composite material that combines high insulation efficiency and high fire resistance and does not shed dust, by adding a heat-resistant gel material that can be dispersed in a very small amount of water to the suspension and dispersion solution of the wet gel particles of nanometer to submicron levels.

A further object of the present invention is to provide high insulation performance and high thermal conductivity on both sides of the outer layer of the aerogel product, or to provide a surface layer with low dielectric constant and high conductivity, and apply it to an insulation layer covering the outside of a high-temperature pipeline in a clean room or a machine tool platform with an insulation layer, thereby reducing heat loss in the pipeline or at the boundary of the machine tool platform, improving the effect of energy saving and reducing carbon emissions, and using conductive technology to provide conductivity to the outside of the insulation layer platform covering the high-temperature pipeline, thereby suppressing the generation of static electricity caused by friction. A further main object of the present invention is to provide high fire protection performance to the outside of the composite structure, provide high insulation to the inside, and apply it to the insulation of the heat dissipation of the lithium battery module of an electric vehicle, to avoid thermal runaway of the lithium battery module of an electric vehicle, and improve the safety of the electric vehicle.

Chinese Patent Application Publication No. 113873697A Taiwan Patent Application Publication No. 201542457 Taiwan Patent Application Publication No. 655094 Taiwan Patent Application Publication No. 663062 Taiwan Patent Application Publication No. 743082 Taiwan Patent Application Publication No. 765609 Taiwan Patent Application Publication No. 535658 Taiwan Patent Application Publication No. 643888

In the present invention, first, in the process of preparing the aerogel, the condensed solution is dispersed in a large amount of dispersion solution by a suspension dispersion technique, and then a small amount of heat-resistant gel material is added to disperse uniformly. The suspension dispersion solution is injected into a preformed fiber blanket, and the gel is formed. After drying at normal pressure, an aerogel fiber preformed composite structure material with low thermal conductivity and high fire resistance is prepared. Then, a fiber fabric containing a heat-resistant resin or a heat-resistant non-organic film is further used to preform the aerogel structure material to cover the surface layer, and then cured at high temperature to crosslink and cure the fiber fabric containing a heat-resistant resin or the heat-resistant non-organic film and the gel material, to prepare a fiber-reinforced plastic (LFRP) with a high strength and high density on the surface, which covers the aerogel blanket product with high insulation and high fire resistance. This combination product is a composite material that covers an aerogel that does not fall dust, has high insulation efficiency, high fire resistance, and low dielectric constant or antistatic properties.

In order to solve the above problems, the aerogel coated with a heat-resistant material according to one embodiment of the present invention relates to an aerogel composite material that is dust-free, has high thermal insulation, high fire resistance, and a low dielectric constant. The embodiment of the present invention includes a mixed hydrolysis step (1) in which a siloxane precursor is added to an ethanol aqueous solution and stirred to form a mixed solution, the siloxane precursor includes a siloxane compound and a hydrophobically modified siloxane compound substituted with a different alkyl group chain length, or a combination thereof, and then an acid catalyst is added to the mixed solution to cause a hydrolysis reaction; a large amount of a dispersion aqueous solution is added to the mixed solution and stirred at high speed to suspend and disperse the condensed solution in the aqueous solution, the dispersion solution includes an alkali catalyst, and a condensation reaction is caused to form a suspended and dispersed submicron-level condensed solution, and then a suspended and dispersed submicron-level condensed solution is dispersed in the aqueous solution. A condensation and dispersion step (2) of adding a heat-resistant gel material dispersible in a small amount of water to the condensed solution; a structure formation step (3) of injecting the suspended and dispersed sol solution into a preform mold, further condensing the dispersed sol solution to form a solid wet gel preform mold structure, injecting the suspended and dispersed sol solution into a mold containing a fiber material, further condensing the suspended and dispersed sol solution in the preform mold containing a fiber material to form a solid wet gel preform composite structure containing a fiber material, and coating the surface of the aerogel structure with a heat-resistant gel material dispersible in a small amount of water; and a structure formation step (4) of combining a high-temperature heating furnace with microwave technology to form a high-temperature wet gel preform mold structure. A normal pressure drying step (4) is carried out by providing a normal pressure and high temperature drying airflow in a heating furnace to rapidly evaporate the solvent in the solid aerogel molded structure, and by utilizing microwave technology with a water molecule rotation frequency to rapidly rotate the water molecules inside the aerogel molded structure, the hydrogen bonds of the water molecules are broken, and the shrinkage and bursting of the aerogel structure caused by the interfacial tension of the water molecules during the drying process is suppressed. The normal pressure drying step (4) is carried out by combining the above technologies to rapidly obtain a preformed aerogel material with a porous structure and low thermal conductivity and low dielectric constant. A gel material solution that can withstand high temperatures of 300 degrees or more is prepared, and the gel material solution is applied to the surface of a heat-resistant fiber fabric or an inorganic template. (5) an outer layer coating step of further using a heat-resistant fiber fabric or a non-organic film plate impregnated with a gel material solution to coat the aerogel preformed material in multiple layers; and (6) curing the resin of the aerogel preformed material coated with the heat-resistant fiber fabric/non-organic film plate containing the heat-resistant gel material in multiple layers in a high-temperature curing environment to obtain a composite material coated with aerogel and fiber-reinforced plastic that has high strength, high density, and does not shed dust. The outer layer prepared by the above process technology is a fiber-reinforced plastic (like-fiber) that has high strength, high modulus, and high density. The process includes a hardening and molding step (6) in which the LFRP (fiber reinforced plastic) coating layer is made of a high-strength, high-density aerogel blanket, and the inner layer is an aerogel structural composite material containing a small amount of heat-resistant gel material that has high thermal insulation and low dielectric constant. The product of this combination is an aerogel composite structural material that does not shed dust and has high thermal insulation efficiency. The process also includes a surface treatment step (7) in which the high-strength, high-density LFRP is used to cover the high-insulation aerogel blanket, and the surface of the FRP coating layer is treated by surface treatment techniques such as polishing and surface painting using high-pressure spraying, sand blasting, wet sand blasting, or dry sand blasting. The aerogel composite structural material of this process combination has high strength, high heat resistance, no dust, and high thermal insulation efficiency.

In the mixed hydrolysis step (1), the siloxane compound includes tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), or a combination thereof. The hydrophobically modified siloxane compound includes one or a combination of hydrophobically modified siloxanes substituted with different alkyl group chain lengths, such as methyltrimethoxysilane (MTMS), propyltrimethoxysilane (PTMS), hexyltrimethoxysilane (HTMS), octyltrimethoxysilane (OTMS), and hexamethyldisilane (HMDS). In the entire mixed solution, the molar ratio of the content of the siloxane compound and the hydrophobically modified siloxane compound is 0:100 mol% to 95:5 mol%, and the purpose of adding the hydrophobically modified siloxane compound is to reduce the phenomenon of cracks occurring in the aerogel structure during the drying process. On the other hand, the purpose of adding the siloxane compound is to adjust the microstructure inside the aerogel structure and increase the pore structure and porosity in the structure, thereby reducing the thermal conductivity or increasing the thermal insulation.

Furthermore, in the mixed hydrolysis step (1), the higher the content ratio of the acid catalyst in the mixed solution, the faster the hydrolysis rate; however, the inclusion of a large amount of acid ions generates ion conductivity due to the action of an electric field, so the dielectric constant and dielectric loss of the aerogel structure are also significantly increased. Relatively, the lower the content ratio of the acid catalyst, the slower the overall hydrolysis rate. Therefore, the present invention reduces the content of the acid catalyst and increases the process temperature to accelerate the hydrolysis rate of trace amounts of acid ions, thereby significantly reducing the overall content of added acid ions and condensed base ions. Meanwhile, the alcohol molecules generated in large quantities during the hydrolysis of siloxane compounds and hydrophobic siloxane compounds are replaced by ultrapure water in the hydrolysis process with organic solvents such as ammonia water and alkanes, thereby reducing the addition of organic solvents such as ammonia water and alkanes, which not only reduces the impact of organic solvents such as ammonia water on the dielectric properties of the aerogel, but also reduces the danger and environmental pollution associated with the treatment of organic solvents during the process, and reduces the overall cost of preparing the aerogel.

Furthermore, in the mixed hydrolysis step (1), the higher the content of the above solvent in the entire mixed solution, the higher the porosity in the subsequently dried wet gel particles. Relatively, the lower the content of the above solvent in the entire mixed solution, the lower the porosity in the subsequently dried wet gel particles. The above solvents include ethanol, recycled ethanol aqueous solution, recycled methanol aqueous solution, recycled water, ultrapure water, filtered water, distilled water, or combinations thereof.

In addition, in the condensation dispersion step (2), a dispersion solution containing a large amount of ethanol containing a trace amount of an alkali catalyst is added, and the mixed solution of siloxane molecules or hydrophobically modified siloxane molecules in the hydrolysis solution is stirred at high speed by an emulsifier or homogenizer, and the hydrolyzed siloxane molecules or hydrophobically modified siloxane molecules are diluted and stirred with a large amount of dispersion solution to form nanometer- to submicron-level circular molecular suspension oil droplets, which are dispersed in a large amount of dispersion solution. The main purpose of using this step is to dilute and stir the hydrolyzed siloxane molecules or hydrophobically modified siloxane molecules with a large amount of dispersion solution to form nanometer- to submicron-level circular molecular suspension oil droplets, thereby increasing the reaction contact area and accelerating the condensation reaction rate, thereby rapidly tiring the formed nanometer- to submicron-level wet gel particles. Another purpose of using this step is to clearly increase the specific surface area of the formed nanometer- to submicron-level wet gel particles in the subsequent drying process, thereby accelerating the drying rate.

Furthermore, in the above-mentioned condensation dispersion step (2), the present invention adds a heat-resistant gel material that can be dissolved and dispersed in a very small amount of water to the above-mentioned nanometer- to submicron-level wet gel particles and dispersion water, and uses the heat-resistant gel material that can be dissolved and dispersed in water to cover the surface of the above-mentioned nanometer- to submicron-level wet gel particles in the subsequent drying process, and the coating gel material serves as a stabilizer for the wet gel particle structure, so that the product prepared by this preparation method does not crack, and there is no need to add a large amount of organic solvents such as hydrophobically modified toluene and n-hexane, and there is no need to add auxiliary agents such as surfactants during preparation, and there is no need to perform the hydrophobically modified organic solvent replacement step multiple times.

Furthermore, the structure formation step (3) includes a preforming and molding step. In the preforming step, the mixed suspension dispersion solution of the hydrolyzed siloxane molecules and hydrophobically modified siloxane molecules of nanometer to submicron level formed is injected into a preforming mold, and the wet gel particles of nanometer to submicron level are further condensed and aggregated to form a gel structure of a preforming structure, and a preforming gel structure of various sizes of tubes, plates, or specific appearance forms is formed. The present invention forms a three-dimensional wet gel particle network structure by condensing and condensing the aerogel wet gel of nanometer to submicron level by gelling, and forms a mold structure by condensing and condensing the aerogel wet gel of nanometer to submicron level by gelling, and forms an organic-inorganic composite structure by coating the surface of the aerogel structure using a heat-resistant gel material that can be dispersed in a small amount of water. In another embodiment, the condensed suspension-dispersed sol solution in which no condensation reaction has occurred is injected into a preform containing a fiber material, the hydrolyzed wet gel particles of nanometer to submicron size enter the preform, and are further condensed and assembled between the fiber structure to form a three-dimensional wet gel particle network structure, and the silicon-based wet gel particles and the fiber material are bonded to each other by gelling in the preform, and then further condensed in the preform to form a solid wet gel molded structure containing the fiber material, and the surface of the aerogel structure is coated with a heat-resistant gel material that can be dispersed in a small amount of water to form an organic-inorganic composite structure.

Furthermore, in the above-mentioned structure formation step (3), the hydrolyzed siloxane molecules and hydrophobically modified siloxane molecule dispersion solution are injected into the fiber-containing structure using techniques such as impregnation, suction, high-pressure injection, high-pressure injection, high-pressure spray, or vacuum adsorption, to perform composite processing of the fiber-containing aerogel thin plate.

Furthermore, in the above-mentioned structure formation step (3), the gel material that can withstand high temperatures of 300 degrees or more includes one or a combination of inorganic gels or thermosetting resins, and more specific examples include water glass, inorganic silicon resin, copper oxide-phosphate gel, silicate gel, phosphate-silicate gel, sulfate gel, magnesium oxide-silicon dioxide-borax inorganic gel, epoxy resin, polyimide, polyetherimide, polyphenylene ether, polyphenylene sulfide, polyether ketone liquid crystal polymer, polytetrafluoroethylene, polymelamine, polyphenol aldehyde, polymelamine-formaldehyde, polyamide, polyamide ester, silica gel, and other various organic or inorganic gel materials, or combinations thereof.

Furthermore, in the above-mentioned structure formation step (3), the heat-resistant fibers of the present invention include metal fibers, inorganic fibers, liquid crystal fibers, and organic fibers, and specific examples include various metal fibers or metal rods of the micrometer to nanometer order, glass fibers, carbon fibers, quartz fibers, ceramic fibers, rock wool fibers, Kevlar polyamide fibers, Nomex polyamide fibers, nylon fibers, polyester fibers, biodegradable inorganic fibers, or various porous loose fibers prepared from biodegradable organic fibers, mats, paper, blankets, ropes, thick boards, etc., or combinations thereof.

In addition, in the atmospheric drying step (4), the above-mentioned solidified aerogel preform structure is placed in a combined high-temperature equipment and microwave equipment, and a high-temperature heating furnace, UV light, IR or other heat source is used to provide a high-temperature airflow at the azeotropic temperature of the above-mentioned mixed solvent, and a microwave frequency with a water molecule rotation frequency is combined, so that the water molecules inside the aerogel molded structure rotate at high speed following the microwave frequency, destroying the hydrogen bonds of the water molecules in the aerogel structure, and accelerating the drying speed of the product. By combining the above technologies, the water molecules and alcohol molecules inside the aerogel structure are dried quickly, and the shrinkage and bursting phenomenon of the aerogel structure caused by the interfacial tension of the water molecules is suppressed. In the general solvent azeotropic vaporization step (4-1), the high-speed azeotropic vaporization temperature of a large amount of mixed solvent in the above-mentioned solidified aerogel molded structure is between 60 and 90°C. In the above azeotropic temperature environment, the vaporized steam is guided to a heat exchange recovery equipment, and the above The method includes a solvent recovery step (4-2) in which the aqueous alcohol is cooled and condensed in the heat exchange recovery equipment and recovered, the purpose of which is to reduce costs and reduce environmental pollution; and a bumping step (4-3) in which the temperature of the drying equipment for drying the aerogel preformed structure is adjusted to a high temperature above the bumping temperature of the mixture, and combined with high-speed rotation of microwave frequency to break the hydrogen bonds of the water molecules in the aerogel structure and provide frictional heat of the solvent molecules at a high speed, causing the excess mixed solvent inside the aerogel that is close to drying to bump at a high speed and form a positive pressure, and using this positive pressure inside the aerogel structure to suppress the shrinkage phenomenon that occurs during the drying process of the aerogel, and using the positive pressure inside the aerogel structure to generate a large number of nanometer- to submicron-level micropores during the expansion process of the aerogel structure to increase the porosity and heat insulating properties of the aerogel product, the bumping temperature of which is 110 to 180°C.

In the outer layer coating step (5), a gel material solution containing organic or inorganic resin or a combination thereof that can withstand high temperatures of 300 degrees or more is prepared, and the heat-resistant gel material solution is impregnated or spray-coated into a heat-resistant fiber fabric, a heat-resistant non-organic film, or a heat-resistant non-organic thin plate, and the heat-resistant gel material solution is uniformly spray-coated onto the surface of the heat-resistant fiber fabric, the heat-resistant non-organic film, or the heat-resistant non-organic thin plate, and then a product such as a heat-resistant material containing this heat-resistant gel material is further used to coat the surface of the aerogel preformed structural material.

Furthermore, in the above-mentioned outer layer coating step (5), the heat-resistant non-organic film, heat-resistant non-organic thin plate, or one or a combination thereof of the heat-resistant fiber includes a heat-resistant film, thin plate, such as a metal, inorganic, or organic-inorganic composite, with respect to a heat-resistant non-organic film or heat-resistant non-organic thin plate. Furthermore, the metal film plate includes a film prepared from a metal material such as aluminum, stainless steel, or copper, or a combination thereof. The inorganic film plate includes a mica sheet, a graphite sheet, a graphene sheet, a glass sheet, and various ceramic sheets, sheets, thin plates, or combinations thereof prepared from metal oxides, metal silicon nitride compounds, and metal silicon carbide compounds. The organic-inorganic composite film includes a heat-resistant organic-inorganic composite film, thin plate, or inorganic-inorganic composite film, thin plate, etc., produced by combining aluminum, stainless steel, copper, mica sheet, graphite, graphene, glass, ceramic, metal oxides, metal silicon nitride compounds, and metal silicon carbide compounds with various organic gels or various inorganic gels. Furthermore, the heat-resistant fibers include one or a combination of quartz fiber, glass fiber, ceramic fiber, carbon fiber, organic fibers such as nylon fiber, polyester fiber, and polyfluoride fiber, liquid crystal fibers such as Kevlar polyamide fiber and Nomex polyamide fiber, and various porous loose fibers prepared by compounding various celluloses, biodegradable inorganic or organic fibers, etc., straw, paper, blankets, ropes, and thick boards.

Furthermore, in the above-mentioned outer layer coating step (5), the heat-resistant gel material solution includes one of inorganic gel, thermoplastic or thermosetting organic resin, or a combination thereof. Specific examples of the heat-resistant inorganic gel include water glass gel, inorganic silicon resin gel, copper oxide-phosphate gel, silicate gel, phosphoric acid-silicate gel, sulfate gel, magnesium oxide-silicon dioxide-borax inorganic gel, etc., or a combination thereof. The heat-resistant thermosetting organic gel includes epoxy resin, polyimide resin, polyetherimide resin, polyphenylene ether resin, polyphenylene sulfide resin, polyether ketone liquid crystal polymer resin, polytetrafluoroethylene resin, polymelamine resin, polyphenol aldehyde resin, polymelamine-formaldehyde resin, polyamide gel, polyamide ester gel, polypropylene acid resin gel, silica gel, etc., or a combination thereof.

Furthermore, for the entire outer layer coating step, the solid content concentration of the heat-resistant gel material solution is 10.0-75.0wt%. The gel material solution is sprayed or coated on the fiber fabric, the heat-resistant non-organic film, or the heat-resistant non-organic thin plate to coat the aerogel preformed composite material in multiple layers. The lower the concentration of the heat-resistant gel material solution, the higher the efficiency of the gel material solution penetrating into the fiber fabric and the easier the processing. However, the fiber fabric impregnated with the prepared gel material solution will have a lower density of the aerogel molded composite material coated in multiple layers, and the pore content in the structure will be increased, making it easier for aerogel dust to leak. Relatively, the higher the concentration of the heat-resistant gel material solution, the more the content of the gel material solution covering the surface of the fiber fabric, and the strength and density of the aerogel molding composite material coated with the fiber fabric impregnated with the prepared gel material solution in multiple layers will be higher, and the leakage of aerogel dust will be less likely to occur, but processing will be more difficult and the film thickness will be more difficult to control. This is because the concentration of the impregnating gel material solution is used to control the molding processing and dust-proof properties of the aerogel molding composite material coated with the fiber fabric impregnated with the gel material solution in multiple layers, and most preferably the concentration of the gel material solution is 30 to 50.0 wt%.

The curing and molding step (6) further includes a solvent drying step (6-1) and a crosslinking and curing step (6-2). In the solvent drying step, the gel solution is impregnated or applied to the surface of a fiber fabric or a heat-resistant film/thin plate to form a multi-layered aerogel preformed composite material, which is then left at the boiling point of the solvent impregnated in the gel solution to evaporate the solvent in the gel solution and reduce the formation of defects or bubbles. The gel material is a room temperature curing resin, and hardens with the resin during the drying period of the solvent, so this is called the room temperature drying and curing step, in which a composite material is formed in which silica aerogel is coated with a fiber-reinforced plastic (LFRP) inorganic material that has high strength and high density and does not fall dust.

Furthermore, a composite material is provided in which silica aerogel is coated with a fiber-reinforced plastic (LFRP) inorganic material, which has high strength, high fire resistance, high thermal insulation, antistatic properties, and no dust leakage. The related products have properties such as high strength, high hardness, and high fire resistance, and can be applied to high-temperature processes in clean rooms and the safety protection of heat dissipation of lithium battery modules in electric vehicles. The object of the present invention is to provide an improved aerogel composite preparation technology for preparing a composite material in which an aerogel structure is coated with an inorganic material that has high thermal insulation efficiency, high fire resistance, and no dust leakage. Another object of the present invention is to improve the drawback that silica aerogel or organic-inorganic composite aerogel coated with an organic film is fatigued or decomposed when applied at high temperatures. Meanwhile, the present invention is applied to a heat insulating layer or a machine tool platform having a heat insulating layer that covers the outside of a high-temperature pipeline in a clean room, thereby reducing the heat loss in the pipeline or at the boundary of the machine tool platform, and improving the effects of energy saving and carbon emission reduction.

In the above-mentioned solvent drying step (6-1), the gel material solution with high heat resistance, high strength and no dusting impregnated or applied to the surface of the fiber fabric or heat-resistant film/sheet evaporates along with the organic solvent, and the gel material solution gradually dries. Here, the drying temperature of the solvent is determined based on the boiling point of the mixed solvent of the gel material solution. In some embodiments, the solvent is ethanol, and the drying temperature of the solvent is 60-75°C. In other embodiments, the solvent is methyl ethyl ketone, and the drying temperature of the solvent is 80-90°C. In other embodiments, the solvent is water, and the drying temperature of the water-solvent is 80-102°C. In view of the danger of the above-mentioned drying solvent, the evaporation of the above-mentioned solvent is recovered by a recovery device, thereby reducing the content of the evaporated solvent in the working environment and reducing the risk.

In another embodiment, in the solvent drying step (6-1), the gel material solution impregnated or applied inside the fiber fabric or heat-resistant film/thin plate evaporates along with the organic solvent, the gel material solution gradually dries, and the fiber fabric or heat-resistant film/thin plate impregnated or applied with the gel material solution acquires high heat resistance and high strength, and the fiber fabric or heat-resistant film/thin plate impregnated with the gel material solution without dusting covers the aerogel composite material.

In the crosslinking and curing step (6-2), the aerogel preformed composite material coated with multiple layers of fiber fabric or heat-resistant film/thin plate impregnated or coated with the gel material solution undergoes crosslinking reactions between inorganic gel or thermosetting polymer chains and between inorganic gel or thermosetting molecules and aerogel molecules at a specific crosslinking and curing temperature, and is bonded and cured. For example, inorganic gels such as water glass gel and inorganic silicone resin gel, and thermosetting polymers such as epoxy resin, have a crosslinking and curing temperature of about 120 to 200°C, and in other embodiments, the most preferred crosslinking and curing temperature is 150 to 180°C or 185 to 190°C. On the other hand, inorganic gels such as copper oxide-phosphate gel, silicate gel, and phosphoric acid-silicate gel, and thermosetting polymers such as polyimide, have a crosslinking and curing temperature of about 120 to 325°C, and in other embodiments, the highest crosslinking and curing temperature is 320 to 325°C. In the crosslinking and curing step (6-2), a crosslinking reaction occurs between the molecules of the fiber fabric or heat-resistant film/thin plate impregnated or coated with the organic or inorganic resin solution at a specific crosslinking temperature, forming an aerogel molded composite material that is covered in multiple layers with the fiber fabric or heat-resistant film/thin plate impregnated or coated with the gel material solution, which has high thermal insulation, high fire resistance, and high strength and does not shed dust.

Furthermore, in the surface treatment step (7), the aerogel and the material are coated with the above-mentioned heat-resistant film having high strength, low thermal conductivity, low dielectric constant, and high fire resistance, and one or a combination of aerogel fire and heat insulating paints are used for polishing, spraying, and surface spray painting, and by combining processes such as cleaning and surface protection, the aerogel is coated with a heat-resistant film having high strength, low thermal conductivity, low dielectric constant, and high fire resistance.

Furthermore, in the above-mentioned preparation method, the aerogel material inside the aerogel molding composite material with low thermal conductivity and low dielectric constant and coated with multiple layers has a porous structure, with a porosity of 50.0-75.0%, a density of 0.20-0.60g/ ^cm3 , a thermal conductivity of 0.020-0.045W/mk, a dielectric constant of 1.30-1.85, a flame resistance property of UL94-5VA grade or higher, and a maximum heat resistance temperature of 1200 degrees. Under the condition that the hot spot temperature is about 650 degrees and the product thickness is 2mm-3mm, the insulation temperature is reduced to about 200 degrees or less.

The present invention rapidly produces a composite material in which aerogel is coated with a high-strength heat-resistant material. First, using an improved gel-sol technology, the suspension dispersion solution is rapidly condensed by equipment such as an emulsifier or homogenizer under conditions of low organic solvent and acid alkali ion concentrations, and then the condensed suspension dispersion solution is impregnated into a preform or a preform containing fibers to prepare an aerogel or aerogel/fiber composite structural material with a specific molded structure that combines high thermal insulation and low dielectric constant. Furthermore, the aerogel or aerogel/fiber composite structural material is coated in a single layer or multiple layers with a fiber fabric or heat-resistant film/heat-resistant thin plate impregnated or coated with a gel material solution, and then crosslinked curing and surface treatment are performed to prepare a composite structural material coated with aerogel in multiple layers that combines high fire resistance, low thermal conductivity, and does not shed dust. The related products can be provided for clean rooms in various high-tech industries, achieving the effects of energy saving and carbon emission reduction, and will be applied to the safety protection of electric vehicles and hydrogen vehicles in the future.

The present invention is configured as described above and therefore provides the effects described below.
1. The preparation method of the present invention improves the drawback of the conventional aerogel insulation material being easily shed, and promotes the wide application of aerogel insulation materials. The present invention prepares an aerogel composite material with high strength, high fire resistance, no dusting, and high insulation. The aerogel composite material uses an improved sol-gel technology, so a large amount of organic solvents, surfactants, adhesives, and other substances are not added during the process, and the preparation process of the aerogel composite material does not require a long time to replace the solvent, and does not require supercritical drying technology, and only uses normal pressure drying technology to recover the solvent. The overall process is simple, safe, and economical, and the process speed required to complete the product is shortened to 12 to 48 hours. Alternatively, the aerogel or aerogel/fiber composite material, etc. are prepared in a continuous production manner, thereby improving production efficiency.
2. The preparation method of the present invention can easily adjust the porosity, pore size, porosity between the porous aerogel particles, and the denseness of the aerogel structure by utilizing factors such as the ratio of the siloxane compound and the hydrophobically modified siloxane compound, the content of the hydrolysis solvent, the content of the aqueous dispersion, the stirring speed of the dispersion equipment such as an emulsifier or homogenizer, and the contents and ratios of the acid catalyst and the alkali catalyst.
3. The preparation method of the present invention utilizes the repulsive force of hydrophilic-hydrophobic modification and high-speed stirring to form fine wet gel particles by siloxane compounds and hydrophobically modified siloxane compounds, and accelerates the drying speed and reduces the shrinkage property. In this way, other hydrophobically modified organic solvents such as cyclohexane, benzene, isopropanol, ammonia water and large amounts of surfactants other than alcohols are not added, and the acid catalyst and alkali catalyst are controlled to a very low concentration, so that the thermal conductivity, fire retardant performance and dielectric properties of the aerogel material can be further adjusted, and the production cost of the aerogel composite material can be reduced.
4. The preparation method of the present invention provides a high-speed condensation dispersion solution technology using an emulsifier or homogenizer, and adds a small amount of heat-resistant gel material dispersible in water to the condensation dispersion aqueous solution, and fills the condensation dispersion solution into a preform or a preform containing fibers to perform gelation molding. In the subsequent gelation process, the wet gel particles are mutually assembled in the preform or the preform containing fibers to form a network aerogel structure. Then, the aerogel molding structure is prepared by further drying, which has different sizes of tubes, plates, and specific appearance forms. The products prepared using this technology save a large amount of organic solvent and have a high process speed compared to other technologies.
5. To solve the problem of aerogel dusting, the present invention provides a fiber-reinforced plastic (LFRP) coating technology, which is applied to heat-resistant metal, inorganic or organic-inorganic composite film, thin plate or heat-resistant fiber fabric so as to be impregnated with a heat-resistant organic or inorganic gel body, and then coated with aerogel preformed composite material in a single layer or multiple layers, and crosslinked and cured in a normal pressure and high temperature environment to form a composite material in which the fiber-reinforced plastic (LFRP) coats the aerogel in multiple layers. This technology prepares aerogel composite material with high strength, high thermal insulation and high fire resistance and no dusting.
6. The preparation method of the present invention adjusts the strength, temperature resistance, rigidity, density, electrical conductivity, thermal conductivity, dielectric properties, etc. of the outer layer of the composite material coated with LFRP by the type of resin and the quality of the coating material. The preparation technique of the present invention makes the aerogel composite coated with LFRP in multiple layers have a porosity of 50.0-75.0%, a density of 0.20-0.60g/ ^cm3 , a thermal conductivity of 0.020-0.045W/mk, a dielectric constant of 1.30-1.85, a flame resistance of UL94-5VA grade or higher, and a maximum heat resistance temperature of 1200°C. Under the condition that the hot spot temperature is about 850°C and the product thickness is 2mm-3mm, the insulation temperature is reduced to about 200°C or less.

Other objects, configurations and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the invention.

FIG. 1 is a flow chart showing the steps according to a first embodiment of the present invention, which illustrates a flow chart for preparing an aerogel composite material in which a heat-resistant gel material having high thermal insulation, high fire resistance, high strength, and no dust is applied to a fiber fabric or a heat-resistant film/thin plate to form a multi-layer coating. FIG. 1 shows a photograph of the appearance of a composite material prepared by a preparation method according to a first embodiment of the present invention, in which an aerogel is coated with tubular fiber-reinforced plastic (LFRP) that has high strength, high fire resistance, high thermal insulation, and does not shed dust. In the first embodiment, the aerogel is coated using glass fibers of three different types of heat-resistant gel materials, and the outer shell is coated with heat-resistant fiber-reinforced plastic (LFRP) that has high strength and high hardness. The inside of the coated outer shell is an aerogel material that has low thermal conductivity and low dielectric constant and does not shed dust. The cross section of a pure aerogel with low thermal conductivity inside a composite material prepared by the preparation method according to the first embodiment of the present invention, in which an aerogel is coated with a fiber-reinforced resin that does not shed dust and has high strength, high fire resistance, and high thermal insulation properties, is photographed with a scanning electron microscope (SEM) at a magnification of 300 times. FIG. 1 shows a photograph of the appearance of a composite material prepared in a second embodiment of the present invention, in which an aerogel is coated with a fiber-reinforced resin that does not shed dust and has high strength, high fire resistance, and high thermal insulation properties. In the second embodiment, heat-resistant inorganic gel is applied to a mica sheet in both upper and lower layers to reinforce the composite material coating the aerogel, providing further heat resistance and high strength. The resin coating layer is reinforced by the highly insulating mica, and the inside of the outer shell structure is an aerogel/fiber composite material with low thermal conductivity. The cross section of the inside of a composite material according to the second embodiment of the present invention, in which an aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, and high thermal insulation properties and does not shed dust, was photographed with a SEM scanning electron microscope at a magnification of 250 times. FIG. 3 shows a photograph of the appearance of a composite material in which an aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, high insulation, and does not shed dust, which is prepared by a preparation method according to a third embodiment of the present invention. In the third embodiment, heat-resistant inorganic gel is applied to a mica sheet coating layer in two layers, upper and lower, and then a graphene thermal conductive sheet is attached to the outer layer of the mica sheet coated with the heat-resistant inorganic gel, which provides a heat diffusion function and enhances the thermal conductivity performance of the composite material coating the aerogel. FIG. 4 shows a photograph of the appearance of a composite material in which an aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, high insulation, and does not shed dust, which is prepared by a preparation method according to a fourth embodiment of the present invention. In the fourth embodiment, two layers of heat-resistant inorganic gel are applied to a mica sheet, and the composite material in which the aerogel is coated is strengthened by the heat-resistant mica sheet. After that, a heat-conducting metal foil is attached, which provides a heat diffusion function, thereby enhancing the thermal conductivity performance of the composite material in which the aerogel is coated. The fifth embodiment of the present invention shows a photo of the appearance after spraying aerogel fireproof and heat-insulating paint on the surface of a composite material prepared in the above-mentioned second to fourth embodiments, which is made of aerogel coated with fiber-reinforced resin having high strength, high fireproof performance and high heat insulation. In the fifth embodiment, the aerogel fireproof and heat-insulating paint is sprayed on the surface, and this material provides better fireproof and heat-insulating function. FIG. 13 is a schematic diagram showing a fire and insulation test of a product according to a fifth embodiment of the present invention using a high-temperature flame.

Next, we will explain the embodiments of the heat insulating composite material of the present invention, in which the heat resistant material of the present invention is used to coat the aerogel, with reference to the drawings. However, the present invention is not limited to these embodiments, and the members, materials, etc. described below can be modified in various ways within the scope of the present invention.

Figure 1 shows an embodiment of an aerogel composite material and its preparation method, which are dust-free, highly heat-insulating, and highly fire-resistant for use in clean rooms and electric vehicle safety protection according to the present invention, and includes the steps of a mixed hydrolysis step (S1), a condensation and dispersion step (S2), a structure formation step (S3), a normal pressure drying step (S4), an outer layer coating step (S5), a hardening molding step (S6), and a surface treatment step (S7). Each step will be described below.

<Mixing hydrolysis step (S1)>
A siloxane precursor is added to the ethanol aqueous solution to form a mixed solution. The siloxane precursor includes a hydrophobically modified siloxane compound, a siloxane compound, or a combination thereof, and the hydrophobically modified siloxane compound includes a hydrophobically modified siloxane compound having a different chain length. An acid catalyst is then added to the mixed solution to cause a hydrolysis reaction. In some embodiments, the siloxane compound includes tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), or a combination thereof. The hydrophobically modified siloxane compound includes one or a combination of hydrophobically modified siloxanes with different alkyl chain lengths, such as methyltrimethoxysilane (MTMS), propyltrimethoxysilane (PTMS), hexyltrimethoxysilane (HTMS), octyltrimethoxysilane (OTMS), and hexamethyldisilane (HMDS). The purpose of adding the hydrophobically modified siloxane is to reduce the crack phenomenon that occurs in the aerogel structure during drying. The purpose of adding the siloxane is to increase the content of holes in the structure by adjusting the microstructure inside the aerogel structure. In some embodiments, the molar ratio of the total content of the siloxane compound and the hydrophobically modified siloxane is between 0.5 mol% and 40 mol%, and the molar ratio of the content of the ethanol aqueous solution is between 99.5 mol% and 60 mol% for the entire mixed solution.

In this example, the molar ratio of the siloxane compound to the hydrophobically modified siloxane compound is 0:100 to 95:5. In a preferred embodiment of the invention, the molar ratio of the siloxane compound to the hydrophobically modified siloxane compound is 5:95. In other preferred embodiments of the invention, the molar ratio of the siloxane compound to the hydrophobically modified siloxane compound is 0:100 mol% to 40:60 mol%. In the aqueous ethanol solution, the molar ratio of ethanol to water is 0:100 to 50:50. In some preferred embodiments, the molar ratio of ethanol to water is 15:85.

In the mixing and hydrolysis step (S1), the siloxane compound or hydrophobically modified siloxane compound is thoroughly mixed with a large amount of an ethanol aqueous solution containing a trace amount of an acid catalyst, and a hydrolysis reaction (hydrolysis) occurs at the same time during the mixing process. The solvent of the acid catalyst ethanol aqueous solution includes one or a mixture of different compositions of ethanol, ultrapure water, treated water, secondary treated water, etc., and the molar ratio of the total content of the siloxane and hydrophobically modified siloxane mixture to the content of the acid catalyst is 1:0.01 to 1:0.00005. In the siloxane and hydrophobically modified siloxane mixed solution, the higher the content ratio of the acid catalyst, the faster the hydrolysis rate. In other words, the higher the content ratio of the acid catalyst, the higher the ion content in the entire aerogel structure and the higher the dielectric loss of the aerogel. In a preferred embodiment of the present invention, the molar ratio of the total content of the siloxane and hydrophobically modified siloxane mixture to the content of the acid catalyst is 1:0.00014.

<Condensation and Dispersion Step (S2)>
The mixed solution is added with an aqueous dispersion solution, the aqueous dispersion solution contains an alkaline catalyst, and is stirred at high speed using a high speed stirring device such as an emulsifier or homogenizer to cause a condensation reaction to form a sol dispersion solution. More specifically, during the condensation reaction, the condensation reaction temperature, the content of ultrapure water added, and the stirring speed are controlled to adjust the condensation reaction rate and control the aerogel microstructure inside the sol dispersion solution obtained. The volume ratio of the aqueous dispersion solution to the ethanol aqueous solution is 75:25-30:70. In a preferred embodiment of the present invention, the volume ratio of the aqueous dispersion solution to the ethanol aqueous solution is 50:50.

In the condensation and dispersion steps, the condensation reaction time is significantly shortened by increasing the temperature, i.e., the gelation time of the aerogel is effectively shortened in the dispersion-condensation step (S2). When the equivalent ratio of the contents of the alkali catalyst and the acid catalyst is 1.0:1.0, the condensation reaction temperature is 20-55°C, and the condensation reaction time is 20-250 minutes. In some 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.

In the condensation and dispersion step, the mixture of hydrolyzed siloxane molecules and hydrophobically modified siloxane molecules forms hydrolyzed wet gel particles of nanometer to submicron size in the suspension dispersion aqueous solution, and a heat-resistant gel material dispersible in a small amount of water is added to the suspension dispersion aqueous solution, so that the nanometer to submicron size aerogel wet gel is condensed and aggregated to form a network structure during the gelation process, and then the heat-resistant gel material dispersible in a small amount of water covers the surface of the three-dimensional network structure of the aerogel to form an organic-inorganic composite nanometer structural material. The volume ratio of the heat-resistant gel material dispersible in a small amount of water to the dispersion aqueous solution is 0.01% to 5%, and the heat-resistant gel material can withstand high temperatures of 300°C or more.

In other embodiments, the condensation reaction time is obviously shortened when the content of the alkali catalyst increases. The equivalent ratio of the contents of 1.0M alkali catalyst and 1.0M acid catalyst is 0.8:1.0 to 2.0:1.0, and the condensation reaction time is 360 to about 3 minutes. In some embodiments, the equivalent ratio of the contents is 0.8:1.0, and the condensation reaction time is 360 minutes. In still other embodiments, the equivalent ratio of the contents is 1.6:1.0, and the condensation reaction time is about 10 minutes. More specifically, when the equivalent ratio of the contents is less than 1.0:1.0, the condensation reaction time gradually increases and the dielectric loss of the prepared aerogel obviously decreases. When the equivalent ratio of the contents is greater than 1.0:1.0, the condensation reaction time gradually decreases and the dielectric loss of the prepared aerogel obviously increases with the increase in the content of ions. In a preferred embodiment of the present invention, the volume ratio of the contents is 1.2:1.0.

<Structure Formation Step (S3)>
The above-mentioned suspension-dispersed sol solution is poured into a preform mold, and the above-mentioned suspension-dispersed sol solution containing a small amount of heat-resistant gel material is further condensed in the preform mold to form a solid wet gel preform structure. In this molding step, the siloxane aerogel molecules are aggregated by condensation reaction to form siloxane aerogel molecular aggregates, the size of the initial structure of the siloxane aerogel molecules is controlled to 5-10 nm, the initial structure is accumulated to form aerogel wet gel molecules of about 50-100 nm, the aerogel wet gel molecules of 50-100 nm are further accumulated to form larger aggregates, and are interconnected to form a three-dimensional network structure, forming an organic-inorganic composite gel structure material, which is coated on the surface of the three-dimensional network structure of aerogel with a stable heat-resistant gel material containing a large amount of solvent.

In another embodiment, a suspension-dispersed sol solution containing a small amount of heat-resistant gel material is injected into a preform containing a large amount of fibers. Under this condition, the siloxane aerogel molecules are adsorbed on the surface of the fibers, and condensed and accumulated on the surface of the fibers to form 50-100 nm aerogel wet gel molecules, and the 50-100 nm aerogel wet gel molecules are further accumulated between the fibers and the fiber structure to form a three-dimensional aerogel network structure, and further form an organic-inorganic composite gel structure material that covers the surface of the aerogel three-dimensional network structure with a stable heat-resistant gel material containing a large amount of fibers. In the above molding step, the molecular-grade aerogel solution is composite-processed into the fiber material using techniques such as impregnation, suction, injection, perfusion, or vacuum adsorption. Therefore, the above preform is a molding mold or a molding mold containing a fiber material.

In some embodiments, the fiber material includes metal fibers, inorganic fibers, liquid crystal fibers, and organic fibers. More specific examples include, for example, various metal fibers or metal rods of the micrometer to nanometer order, glass fibers, carbon fibers, quartz fibers, ceramic fibers, rock wool fibers, Kevlar polyamide fibers, Nomex polyamide fibers, nylon fibers, polyester fibers, various celluloses, various porous loose fibers prepared from biodegradable inorganic fibers or biodegradable organic fibers, straw mats, paper, blankets, ropes, thick boards, etc., or combinations thereof.

<Normal pressure drying step (S4)>
The solidified wet-gel structure is dried at elevated temperature under atmospheric pressure to obtain a homogeneous structure and low thermal conductivity aerogel preformed composite material, including aerogel plate or aerogel/fiber composite plate. In some embodiments, the drying temperature is 60-150° C.

Furthermore, the drying step includes a solvent vaporization step (S4-1), a solvent recovery step (S4-2), and a solvent bumping step (S4-3).

Vaporization step (S4-1)
The preformed wet gel body in the solid state is left at normal pressure and at the azeotropic vaporization temperature of the mixed solvent, and a large amount of alcohol water molecules are azeotropically vaporized at high speed using the temperature, and the alcohol water molecules of the wet gel body are azeotropically evaporated, distilled, and dried. In some embodiments, the azeotropic temperature of the solvent is 60 to 90°C.

Solvent recovery step (S4-2)
In the azeotropic vaporization temperature environment, the aqueous solution containing a large amount of alcohol in the preformed structure is azeotropically vaporized at a high speed, and the vaporized vapor is guided to a heat exchange recovery device, where the aqueous alcohol is cooled and condensed and recovered. In some embodiments of the present invention, the cooled and condensed aqueous alcohol is an additional recovery product of the process, and the purpose of said recovery is, on the one hand, to recover valuable alcohol by-products to reduce production costs, and, on the other hand, to recover alcohol-containing vapors to reduce pollution to the environment and air.

・Bumping step (S4-3)
The temperature of the environment of the preformed aerogel containing the trace amount of solvent after the vaporization is adjusted to the bumping temperature of the solvent, and the bumping phenomenon occurs, in which the trace amount of solvent contained therein is vaporized at a high speed. In some embodiments, the bumping temperature is 110-150°C. More specifically, in the high temperature environment created by the bumping temperature, the bumping phenomenon occurs due to the trace amount of alcohol water molecules inside the aerogel, and the positive pressure steam generates positive pressure steam inside the aerogel, suppressing the shrinkage or collapse phenomenon occurring during the drying process of the aerogel structure. Meanwhile, the positive pressure expands the aerogel network structure, generating a large number of micropores to make it porous, thereby obtaining the aerogel preformed material. Thus, the preparation method is used to prepare aerogel or aerogel/fiber composite material with low density and high porosity, and its thermal conductivity k is about 0.013-0.018 W/mk. The thermal conductivity k of the aerogel/fiber composite is approximately 0.022-0.032 W/mk, and the flame resistance meets or exceeds the UL94-V0 rating.

In addition, since large amounts of organic solvents and surfactants such as alkanes, aromatic benzenes, and amines are not added, the drying process is safe and aerogel products of higher purity can be prepared. As a result, the high-porosity aerogel plate or aerogel/fiber composite plate prepared does not contain impurities, and the product's properties such as thermal conductivity, dielectric constant, and dielectric loss are further improved.

<Outer layer covering step (S5)>
A gel material solution that can withstand high temperatures of 300°C or more is prepared, and the heat-resistant gel material solution is applied to the surface of a material that can withstand high temperatures of 300°C or more so as to impregnate the surface, and the high-temperature gel material solution is uniformly infiltrated into the heat-resistant material, such as a heat-resistant fiber fabric. The heat-resistant material impregnated with the heat-resistant gel material solution is then further used to coat the aerogel preformed composite material in a single layer or multiple layers. The heat-resistant material includes one or a combination of a non-organic film, a non-organic thin plate, or a heat-resistant fiber, for example, a heat-resistant film. The heat-resistant gel material solution is a heat-resistant inorganic gel material or a thermosetting resin solution, and the heat-resistant gel material of the heat-resistant gel material solution can withstand high temperatures of 300°C or more. The temperatures that other heat-resistant materials, heat-resistant films, and heat-resistant fibers can withstand are also 300°C or more, and in specific examples, the heat-resistant gel material solution includes one or a combination of an inorganic gel, a thermoplastic resin, or a thermosetting resin. The inorganic gel material includes, for example, water glass gel, inorganic silicon resin gel, copper oxide-phosphate gel, silicate gel, phosphoric acid-silicate gel, sulfate gel, magnesium oxide-silicon dioxide-borax inorganic gel. The thermosetting resin includes one or a combination of gel materials such as epoxy resin, polyimide resin, polyetherimide resin, polyphenylene ether resin, polyphenylene sulfide resin, polyether ketone liquid crystal polymer resin, polytetrafluoroethylene resin, polymelamine resin, polyphenol aldehyde resin, polymelamine-formaldehyde resin, polyester gel, polyamide gel, polyamide ester gel, and silica gel. In the entire step of impregnating and covering the fiber fabric with the gel material, the concentration of the gel material solution is 10 to 75.0 wt%. The lower the concentration of the gel material solution, the higher the efficiency of the gel material solution penetrating into the fiber fabric and the easier the processing. However, the density of the aerogel molding composite material coated with the fiber fabric impregnated with the gel solution in multiple layers is low, the content of holes in the structure is high, and the aerogel dust is easily leaked. Relatively, the higher the concentration of the gel solution, the more the content of the gel solution covering the surface of the fiber fabric, and the strength and density of the aerogel molding composite material coated with the fiber fabric impregnated with the gel solution in multiple layers are high, and the aerogel dust is not easily leaked. However, it is difficult to process and difficult to control the film thickness. From the above, the concentration of the gel solution is 30 to 50.0 wt% to optimize the molding process and dust-proof property of the aerogel molding composite material coated with the fiber fabric impregnated with the gel solution in multiple layers by controlling the concentration of the gel solution.

In the outer layer coating step (S5), the heat-resistant non-organic film, heat-resistant non-organic thin plate, or heat-resistant fiber, or a combination thereof, includes heat-resistant films such as metal, inorganic, and organic-inorganic composite as the heat-resistant non-organic film and heat-resistant non-organic thin plate, and the aerogel is coated with the thin plate in a single layer, in a multilayer, or by laminating in a multilayer with the aerogel. Incidentally, coating in a multilayer refers to coating by laminating in a multilayer the same heat-resistant film, and coating by laminating in a multilayer refers to coating by laminating in a multilayer a plurality of types of heat-resistant films. In other words, the present invention does not limit the type of heat-resistant film coating the aerogel preformed composite material to a metal film plate, an inorganic film plate, or an organic-inorganic composite heat-resistant film plate, and to a single layer or a multilayer. Furthermore, the metal film plate includes a film prepared from a metal material such as aluminum, stainless steel, copper, or a combination thereof. Examples of inorganic film plates include mica sheets, graphite sheets, graphene sheets, glass sheets, and various ceramic sheets, sheets, thin plates, or combinations thereof prepared from metal oxides, metal silicon nitride compounds, and metal silicon carbide compounds. Examples of organic-inorganic composite films include heat-resistant organic-inorganic composite films, thin plates, or combinations of inorganic-inorganic composite films, thin plates, etc., produced by combining and compounding fine particles of metals such as aluminum, stainless steel, copper, mica sheets, graphite, graphene, glass, and ceramics, metal oxides, metal silicon nitride compounds, and metal silicon carbide compounds with various organic gels or various inorganic gels. Furthermore, examples of fibers that can withstand high temperatures of 300 degrees or more include quartz fiber, glass fiber, ceramic fiber, and carbon fiber, while organic fibers include nylon fiber, polyester fiber, and polyfluoride fiber, and liquid crystal fibers include Kevlar polyamide fiber, Nomex polyamide fiber, and various types of porous loose fibers prepared by combining cellulose, biodegradable inorganic, or organic fibers, straw, paper, blankets, rope, and thick boards, or combinations thereof.

<Curing and molding step (S6)>
The aerogel preform composite material is coated with a heat-resistant material such as a heat-resistant film of the fiber fabric layer or multi-layer impregnated with a gel material solution that can withstand high temperatures of 300 degrees or more, and is left at a boiling point temperature for drying the solvent impregnated with the heat-resistant gel material solution, so that the solvent of the gel material solution is evaporated to reduce the formation of defects or air bubbles, and the gel material solution is gradually dried. Here, the drying temperature of the solvent is determined based on the boiling point of the mixed solvent of the gel material solution. In some embodiments, the mixed solvent is ethanol, and the drying temperature of the solvent is 60-75°C. In other embodiments, the mixed solvent is methyl ethyl ketone, and the drying temperature of the solvent is 80-90°C. In still other embodiments, the solvent is water, and the drying temperature of the water solvent is 80-102°C. Therefore, the drying temperature of the solvent in the embodiment is 60-115°C, and the fiber fabric impregnated with the gel material solution obtained after drying will not have a large amount of bubbles and holes due to the drying temperature being too high, which will prevent aerogel dust from leaking in subsequent applications. Then, a curing step is performed to impregnate the heat-resistant gel material solution at a higher curing temperature. The curing temperature is higher than the drying temperature of the solvent, and thus a composite material is obtained in which the aerogel preform is covered with a heat-resistant film, which has high strength, low thermal conductivity, low dielectric constant, and high fire resistance.

In another embodiment, in the solvent drying step, the organic solvent inside the fiber fabric impregnated with the gel material solution evaporates together, and for example, in the composite material in which the heat-resistant film covering the aerogel preform material is formed by covering the non-organic film, the non-organic thin plate, or the fiber that can withstand high temperatures of 300°C or more impregnated with the heat-resistant gel material solution, the solvent evaporates at the drying temperature of the solvent of the heat-resistant gel material. In the case of a room temperature curing resin gel material, the fiber fabric impregnated with the gel material solution hardens with the evaporation of the solvent, obtaining a high-strength, dust-free, and highly insulating aerogel composite material for the safety protection of clean rooms and electric vehicles. In other words, in addition to drying the solvent, this step further includes a gel material resin hardening step, so this step is also called a room temperature drying and hardening step.

In the curing and molding step (S6), the aerogel preformed composite material, which is covered in multiple layers with the heat-resistant fiber fabric or heat-resistant film/thin plate impregnated or coated with the heat-resistant gel material solution, undergoes crosslinking reactions between inorganic gel or thermosetting polymer chains and between inorganic gel or thermosetting molecules and aerogel molecules at a specific crosslinking and curing temperature, and is bonded and cured, for example, between inorganic gels such as water glass gel and inorganic silicone resin gel and epoxy resin as a thermosetting polymer. The crosslinking and curing temperature is about 120 to 200°C. In some embodiments, the most preferred crosslinking and curing temperature is 150 to 180°C or 185 to 190°C. On the other hand, in the case of inorganic gels such as copper oxide-phosphate gel, silicate gel, and phosphoric acid-silicate gel and polyimide as a thermosetting polymer, the crosslinking and curing temperature is about 120 to 325°C, and in some embodiments, the highest crosslinking and curing temperature is 320 to 325°C. In the above (S6) crosslinking and curing step, a crosslinking reaction occurs between the molecules of the heat-resistant fiber fabric or heat-resistant film/thin plate impregnated or coated with the organic or inorganic gel material solution at a specific crosslinking temperature, forming an aerogel molded composite material that is covered with multiple layers of heat-resistant fiber fabric or heat-resistant film/thin plate impregnated or coated with the heat-resistant gel material solution, which has high insulation, high fire resistance, high strength, and does not shed dust.

First Embodiment
FIG. 2 shows a photograph of the appearance of a composite material in which an aerogel is coated with a tubular fiber-reinforced resin (LFRP) having high strength, high fire resistance, high thermal insulation, and no dust, which is prepared by the above-mentioned preparation method of the first embodiment. In FIG. 2, three different types of heat-resistant gel materials are coated in a tubular shape in multiple layers and cross-linked and cured from top to bottom, and the composite material is coated with an aerogel having high strength, high fire resistance, high thermal insulation, and no dust. As shown in the figure, the top surface is a tubular aerogel composite material coated with a white silica gel-based glass fiber reinforced resin. In comparison, the dark color in the middle is a tubular aerogel composite material coated with a polyimide-based glass fiber reinforced resin. The light yellow color on the bottom surface is a tubular aerogel composite material coated with an epoxy resin-based glass fiber reinforced resin.

Figure 3 shows a cross-section of pure aerogel with low thermal conductivity inside a composite material in which aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, and high insulation properties and does not shed dust, prepared by the above-mentioned preparation method of the first embodiment, taken with a scanning electron microscope (SEM) and magnified at 300 times. When observed with an electron microscope, it is clear that the microstructure of the aerogel/fiber composite material is a three-dimensional network aggregate in which submicron to micrometer-class spherical aerogel is aggregated between a large number of fibers. In addition, as can be seen from Figure 3, the aerogel material with low thermal conductivity further includes, in addition to the aerogel aggregate structure, a connection structure in which a small amount of heat-resistant gel material covers between aerogel particles of several micrometers to submicrometers, and a pore structure in which a large number of micrometer-class pores are still formed by connecting between the fibers and the aerogel particles, giving it low thermal conductivity.

Second Embodiment
Figure 4 shows a photograph of the appearance of a composite material in which an aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, high thermal insulation, and does not shed dust, which is prepared by the above-mentioned preparation method of the second embodiment. In the second embodiment, the composite material in which the aerogel is coated is strengthened by applying heat-resistant inorganic gel to a mica sheet in two layers, upper and lower, to provide further heat resistance and high strength, and the resin coating layer is reinforced with highly insulating mica. Here, the inside of the outer shell structure is an aerogel/fiber composite material with low thermal conductivity. The above structure is also laminated in multiple layers, expanding the application field of aerogel.

Figure 5 shows a 250x magnification photograph of the inside cross section of the second embodiment of a composite material in which an aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, and high thermal insulation properties. As shown in Figure 5, the inside of the aerogel composite material of this embodiment is an aerogel/fiber composite material, and the product has a large number of submicron-class aerogel molecules adsorbed on the surface of the fibers, and the pores between the fibers are inter-assembled to form a three-dimensional aerogel network structure, and the overall assembly structure still contains a large number of pores, which give the aerogel/fiber composite blanket the property of low thermal conductivity, and the large number of fibers enhances the properties of the aerogel/fiber composite board, such as appropriate strength.

In the surface treatment step, the surface of the composite material in which the aerogel is coated with the above-mentioned heat-resistant film having high strength, low thermal conductivity, low dielectric constant and high fire resistance is polished, sprayed and surface sprayed with one or a combination of aerogel fire and heat insulation paints, and a combination of processes such as cleaning and surface protection is carried out to form an aerogel molded composite material coated in multiple layers with heat-resistant fiber fabric or heat-resistant film/heat-resistant thin plate having high strength, low thermal conductivity, low dielectric constant and high fire resistance.

Third Embodiment
FIG. 6 shows a photograph of the appearance of a composite material in which an aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, high heat insulation, and does not fall dust, which is prepared by the above-mentioned preparation method of the third embodiment. In the third embodiment, two layers of heat-resistant inorganic gel are applied to the mica sheet coating layer, and then a graphene heat-conducting sheet is attached to the outer layer of the mica sheet coated with the heat-resistant inorganic gel, and this material provides a heat diffusion function. The purpose of the third embodiment is, on the one hand, to provide further heat resistance and high strength, and to strengthen the resin coating layer with the highly insulating mica. On the other hand, to provide heat resistance and high strength, and to strengthen the resin coating layer with the graphene sheet with high thermal conductivity (high electrical conductivity). The above coating structure also has a heat-resistant mica sheet on one side and a heat-resistant graphene heat-conducting sheet or a multi-layer laminate structure on the other side, expanding the application field of aerogel.

Fourth Embodiment
7 shows a photograph of the appearance of a composite material in which an aerogel is coated with a fiber-reinforced resin that has high strength, high fire resistance, high heat insulation, and does not fall dust, which is prepared by the above-mentioned preparation method of the fourth embodiment. In the fourth embodiment, two layers of heat-resistant inorganic gel are applied to the mica sheet coating layer, and then a metal film heat-conducting sheet is attached to the outer layer of the mica sheet coated with the heat-resistant inorganic gel, and this material provides heat diffusion and high conductivity functions. The purpose of the fourth embodiment is to provide heat resistance and high strength on the one hand, and to strengthen the resin coating layer with the highly insulating mica. On the other hand, to provide heat resistance and high strength, and to strengthen the resin coating layer with the metal film with high thermal conductivity (high electrical conductivity). The above structure also has a heat-resistant mica sheet on one side and a heat-resistant metal heat-conducting sheet or a multi-layer laminate structure on the other side, expanding the application field of aerogel.

Fifth Embodiment
FIG. 8 shows a photograph of the appearance of the composite material prepared in the above-mentioned second to fourth embodiments, in which the aerogel is coated with a fiber-reinforced resin having high strength, high fire resistance, and high heat insulation, after spraying the aerogel fireproof and heat-insulating paint on the surface. In the fifth embodiment, the surface is spray-coated with the aerogel fireproof and heat-insulating paint, so that the material provides better fireproof and heat-insulating functions. The purpose of the fifth embodiment is to provide a heat-insulating coating layer that can withstand high temperatures of 1200°C on the one hand, and the flame resistance of the product obtained by this process is UL94-V0 grade or higher, and the maximum heat-resistant temperature reaches 1200°C. Under the condition that the temperature of the high-temperature hot spot is about 650°C and the thickness of the product is 2.78mm, the heat-insulating temperature is reduced to about 200°C or less.

Figure 9 shows the product according to the fifth embodiment, which underwent a fire and insulation test with a high-temperature flame. The test flame hotspot temperature was about 650°C, and the product according to the fifth embodiment was tested for 3 minutes with a thickness of 2.78 mm. During the combustion process, the product did not undergo combustion decomposition, unlike that which occurs with typical organic matter at high temperatures, and no phenomena such as thick smoke caused by charred materials were generated. After insulating the product, the temperature of the back of the product dropped to below 200°C, demonstrating that the developed product has excellent fire and insulation effects and can be applied to prevent thermal runaway in lithium battery modules in electric vehicles.

The present invention has been described above using an embodiment, but the technical scope of the present invention is not limited to the scope described in the above embodiment. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiment. It is clear from the claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

S1 Mixed hydrolysis step S2 Condensation and dispersion step S3 Structure formation step S4 Normal pressure drying step S5 Outer layer coating step S6 Hardening molding step S7 Surface treatment step

Claims (10)

a mixed hydrolysis step of adding a siloxane precursor to an ethanol aqueous solution to form a mixed solution, the siloxane precursor including a hydrophobically modified siloxane compound having different chain lengths, a siloxane compound, or a combination thereof, and then adding an acid catalyst to the mixed solution to cause a hydrolysis reaction;
a condensation and dispersion step of adding an aqueous dispersion solution to the mixed solution, the aqueous dispersion solution containing an alkaline catalyst, and forming a sol dispersion solution by a condensation reaction; and then adding a heat-resistant gel material dispersible in a small amount of water to the sol dispersion solution to obtain a sol dispersion solution containing a heat-resistant gel material, the heat-resistant gel material being resistant to a high temperature of 300° C. or more;
A structure forming step of injecting the dispersed sol solution containing the heat-resistant gel material into a preform mold, and further condensing the dispersed sol solution containing the heat-resistant gel material in the preform mold to form a preformed structure of a solid wet gel, the preform mold including a molding mold or a molding mold containing a fiber material, and the fiber material including one or a combination of metal fiber, inorganic fiber, liquid crystal fiber, porous loose fiber prepared with organic fiber, mat, paper, blanket, rope, and thick board;
drying the solidified wet gel preform structure at normal pressure and drying temperature to obtain an aerogel preform material including an aerogel plate or an aerogel/fiber composite plate, the drying temperature being 60-150°C;
A heat-resistant gel material solution is prepared, the heat-resistant gel material of the heat-resistant gel material solution is resistant to high temperatures of 300°C or more, the heat-resistant gel material solution is applied to impregnate a surface of a non-organic film, a non-organic thin plate, or a fiber that can withstand high temperatures of 300°C or more, and after the heat-resistant gel material solution is uniformly distributed on the surface of the non-organic film, the non-organic thin plate, or the fiber that can withstand high temperatures of 300°C or more, the non-organic film, the non-organic thin plate, or the fiber that can withstand high temperatures of 300°C or more is impregnated with the heat-resistant gel material solution. an outer layer coating step of further using the fiber capable of withstanding high temperatures of 300°C or more to coat the aerogel preform material, and the non-organic film, the non-organic thin plate, or the fiber capable of withstanding high temperatures of 300°C or more is coated with a single layer or multiple layers of aerogel on the aerogel preform material, or is laminated with aerogel in multiple layers to form a composite material in which the aerogel preform material is coated with a heat-resistant material having high strength, low thermal conductivity, low dielectric constant, and high fire resistance;
A hardening and molding step is performed to obtain a composite material that covers the aerogel preform with the heat-resistant material by evaporating the solvent at a solvent drying temperature of the heat-resistant gel material solution, the solvent drying temperature being 60 to 115°C, and then performing a hardening and molding step of impregnating the heat-resistant gel material solution at a hardening and molding temperature, the hardening and molding temperature being higher than the solvent drying temperature, and a composite material that covers the aerogel preform with a heat-resistant film having high strength, low thermal conductivity, low dielectric constant, and high fireproof performance is obtained;
and a surface treatment step of forming an aerogel preformed composite material coated with the heat-resistant film having high strength, low thermal conductivity, low dielectric constant, and high fire retardancy by one or a combination of polishing, spraying aerogel fire-resistant heat-insulating paint, and surface spray painting, in combination with cleaning and surface protection processes, to form an aerogel preformed composite material coated with heat-resistant fiber cloth or heat-resistant film/thin plate in multiple layers, which has high strength, low thermal conductivity, low dielectric constant, and high fire retardancy. 2. The method for preparing a heat insulating composite material of coating aerogel with a heat resistant material according to claim 1, characterized in that, when the heat resistant gel material solution is of room temperature curing type, the non-organic film, the non-organic thin plate, or the fiber capable of withstanding high temperatures of 300°C or more impregnated with the heat resistant gel material solution is cured in the process of evaporating the solvent , thereby obtaining a dust-free, high heat insulating aerogel composite material with high strength, which is used for the safety protection of clean rooms and electric vehicles. The hardening and molding step includes:
A solvent drying step of evaporating a solvent at a solvent drying temperature of the heat-resistant gel material from the composite material in which the heat-resistant film is coated on the aerogel preform material by coating the non-organic film, the non-organic thin plate, or the fiber that can withstand a high temperature of 300° C. or higher, which is impregnated with the heat-resistant gel material solution;
and a crosslinking and curing step of: in a specific crosslinking and curing high temperature environment, the non-organic film, the non-organic thin plate, or the fiber that can withstand high temperatures of 300°C or more and that is impregnated with the heat-resistant gel material solution that coats the outer layer of the aerogel preform material, and the internal thermosetting resin are crosslinked and cured to bond with each other, and after the crosslinking and curing reaction , a composite material is obtained that coats the aerogel preform with the heat-resistant film having high strength, low thermal conductivity, low dielectric constant, and high fire retardancy, and the exterior of the composite material is a fiber-reinforced plastic (LFRP) heat-resistant coating layer that has high temperature resistance, high strength, high density, and does not fall dust, and the interior of the composite material is an aerogel plate or aerogel/fiber composite material that has low thermal conductivity and low dielectric constant. The atmospheric drying step includes:
a vaporization step of leaving the solidified wet-gel preform structure in an azeotropic vaporization temperature environment to azeotropically vaporize the solvent in the solidified wet-gel preform structure and evaporate the solvent to dry it, the azeotropic vaporization temperature being 60 to 90°C;
a solvent recovery step of guiding the vapor of the azeotropic aqueous alcohol solution to a heat exchange recovery device to cool and condense the aqueous alcohol solution and recover the solvent;
and a bumping step of adjusting a temperature of the dry aerogel preform structure to a bumping temperature, bumping a small amount of solvent and water molecules contained in the dry aerogel preform structure at a high speed, generating positive pressure steam to suppress drying shrinkage of the aerogel structure, and generating a large amount of micropores to obtain the aerogel preform material, the bumping temperature being 110-150°C. When the heat-resistant gel material solution contains an inorganic gel resin or a thermosetting resin, the hardening and molding step includes:
A room temperature cross-linking and curing step of evaporating the solvent and cross-linking the curing agent in a room temperature environment to obtain a composite material in which the heat-resistant film covering the aerogel preform has high strength, low thermal conductivity, low dielectric constant, and high fire resistance after curing; or
and curing the thermosetting resin and the non-organic film, the non-organic thin plate, or the fiber resistant to a high temperature of 300° C. or more at a crosslinking temperature to generate a chemical reaction between the thermosetting resin and the non-organic film, the non-organic thin plate, or the fiber resistant to a high temperature of 300° C. or more to bond ... thin plate, the crosslinking temperature is 150-180° C. when the thermosetting resin is an epoxy resin, and the crosslinking temperature is 120-325° C. when the thermosetting resin is a polyimide, and the crosslinking temperature is 150-180° C. when the thermosetting resin is a polyimide, the crosslinking temperature is 120-325° C. after curing, to obtain a composite material covering the aerogel preform with the heat-resistant film, which has high strength, low thermal conductivity, low dielectric constant, and high fire retardancy. The siloxane compound includes tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), or a combination thereof, and the hydrophobically modified siloxane compound includes one or a combination of hydrophobically modified siloxanes substituted with different alkyl group chain lengths, such as methyltrimethoxysilane (MTMS), propyltrimethoxysilane (PTMS), hexyltrimethoxysilane (HTMS), octyltrimethoxysilane (OTMS), and hexamethyldisilane (HMDS). In the siloxane precursor, the molar ratio of the content of the siloxane compound and the hydrophobically modified siloxane compound is 0:100 mol% to 40:60. A method for preparing a heat insulating composite material by coating an aerogel with the heat resistant material according to any one of claims 1 to 5, wherein the heat resistant material is in an amount of mol%. The method for preparing a heat insulating composite material comprising coating an aerogel with a heat resistant material according to any one of claims 1 to 5, characterized in that the heat resistant gel material comprises one or a combination of inorganic gel, thermoplastic resin, or thermosetting resin, the inorganic gel comprises water glass, inorganic silicon resin, copper oxide-phosphate gel, silicate gel, phosphoric acid-silicate gel, sulfate gel, or magnesium oxide-silicon dioxide-borax inorganic gel, and the thermosetting resin comprises epoxy resin, polyimide, polyetherimide, polyphenylene ether, polyphenylene sulfide, polyether ketone liquid crystal polymer, polytetrafluoroethylene, polymelamine, polyphenol aldehyde, polymelamine-formaldehyde, polyamide, polyamide ester, or silica gel. The method for preparing a heat insulating composite material by coating an aerogel with a heat resistant material according to any one of claims 1 to 5, characterized in that the fiber material includes metal fiber, inorganic fiber, liquid crystal fiber, organic fiber, glass fiber, carbon fiber, quartz fiber, ceramic fiber, rock wool fiber, Kevlar polyamide fiber, Nomex polyamide fiber, nylon fiber, polyester fiber, porous loose fiber prepared from biodegradable inorganic fiber or biodegradable organic fiber, mat, paper, blanket, rope, thick board, or combination thereof. The non-organic film and the non-organic thin plate include a metal film plate, an inorganic film plate, and an organic-inorganic composite heat-resistant film, thin plate, or a combination thereof, the metal film plate includes one of aluminum, stainless steel, and copper foil films, or a combination thereof, the inorganic film plate includes one of films or thin plates prepared from mica sheets, graphite, graphene, glass ceramics, metal oxides, metal silicon nitride compounds, and metal silicon carbide compounds, or a combination thereof, and the organic-inorganic composite heat-resistant film includes aluminum foil, stainless steel foil, copper foil, mica thin plate, graphite thin plate, graphene thin plate, and glass thin plate. , ceramic thin plate, metal, and metal oxide fine particles and a heat-resistant film and thin plate manufactured by compounding with gel, or a combination thereof, the fiber that can withstand high temperatures of 300°C or more includes quartz fiber, glass fiber, ceramic fiber, and carbon fiber, and the organic fiber includes nylon fiber, polyester fiber, polyfluoride fiber, Kevlar polyamide fiber, Nomex polyamide fiber, or various porous loose fibers, mats, paper, blankets, ropes, and thick boards prepared by compounding biodegradable inorganic and organic fibers, or a combination thereof. A method for preparing a heat-insulating composite material in which an aerogel is coated with the heat-resistant material according to any one of claims 1 to 5. 6. The method for preparing a heat insulating composite material comprising aerogel coated with a heat resistant film according to claim 1, wherein the heat resistant film is a single layer, a multi-layer, or a multi-layer laminate of a variety of heat resistant films. The heat resistant film is a composite material comprising silica aerogel coated with like-fiber reinforced plastic (LFRP) inorganic material, and the related products have the properties of high strength, high fire resistance, and high thermal conductivity, and can be used in high temperature processes in clean rooms and the safety protection of heat dissipation of lithium battery modules in electric vehicles.