Modified silica aerogel powder and manufacturing method, aerogel slurry and manufacturing method and applications

Abstract

The present invention provides a modified silica aerogel powder with higher water-repellent properties and a larger contact angle, as well as a method for producing the same. Simultaneously, it provides an aerogel slurry with lower thermal conductivity and a method for producing the same, and a method for producing an aerogel insulating felt that has low thermal conductivity, high mechanical strength, and can relatively effectively solve the problem of powder shedding. [Solution] The production of modified silica aerogel powder includes the steps of: (1) modifying halloysite nanotubes with dodecyl methacrylate and pentafluorophenyl methacrylate; (2) producing a silica sol; (3) adding the modified halloysite nanotubes to the silica sol to produce a wet gel; and (5) producing modified silica aerogel powder from the wet gel. The present invention also provides a method for producing an aerogel slurry from the above modified silica aerogel powder and aerogel insulating felt from the aerogel slurry.

Description

[Technical Field]

[0001] This application relates to the technology of manufacturing thermal insulation materials, and more particularly to modified silica aerogel powder and manufacturing methods, aerogel slurry and manufacturing methods, and their applications. [Background technology]

[0002] Silica aerogel is a lightweight, nano-amorphous solid material that, as an emerging super-insulating material, has extremely low thermal conductivity, far lower than the 0.25 W / m·K of static air at room temperature. It offers unparalleled heat insulation and heat retention compared to other materials, and is also low in density, waterproof, flame-retardant, environmentally friendly, corrosion-resistant, resistant to aging, and has a long service life, earning it the title of a super-insulating and heat-retaining material.

[0003] The slurry molding method is a novel solution for compounding silica aerogel and fibrous materials. It involves mixing prefabricated nanopowder with a solvent to produce a slurry, injecting the slurry into a prefabricated fibrous fabric, and then removing the solvent from the fabric to form a fiber-reinforced aerogel composite material. Benefiting from the low cost and excellent compatibility between the slurry and fibers, the slurry can be compounded with various fibrous felts (e.g., glass fiber felt, quartz fiber felt, alumina fiber felt, and mullite fiber felt) to produce aerogel composite thermal insulation felt that combines flexibility with excellent mechanical properties.

[0004] Conventional slurry molding methods produce composite insulation felts with relatively high thermal conductivity, low mechanical strength, and inability to withstand high temperatures. Therefore, achieving high-speed, low-cost production of silica aerogel composite insulation felt while providing the material with flexibility, good mechanical properties, excellent insulation performance, and high-temperature resistance is of significant practical importance. [Overview of the project] [Problems that the invention aims to solve]

[0005] To solve the above technical problems, a modified silica aerogel powder with higher water-repellent properties and a larger contact angle has been developed, and at the same time, an aerogel slurry with lower thermal conductivity has been developed. The aerogel insulating felt produced after bonding with fiber felt has low thermal conductivity, high mechanical strength, and can relatively well solve the problem of powder shedding. This application provides a modified silica aerogel powder and a method for producing it, an aerogel slurry and a method for producing it, and its applications. [Means for solving the problem]

[0006] According to the first aspect, the present application provides a method for producing modified silica aerogel powder, Step S1 involves adding dodecyl methacrylate, pentafluorophenyl methacrylate, an organic solvent, and halloysite nanotubes to a reaction vessel, adding an initiator, controlling the reaction temperature to 70-80°C, reacting for 4-8 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use. Step S2 involves stirring and mixing a silicon source, deionized water, anhydrous ethanol, and n-hexane at room temperature to produce a silicon source precursor solution. Step S3 involves adding an acid catalyst to the silicon source precursor solution prepared in step S2, adjusting the pH of the solution to 2-3, and carrying out a hydrolysis reaction under heating in a water bath to produce a silica sol. Step S4 involves adding a basic catalyst to the silica sol produced in step S3, adjusting the pH of the solution to 6-7, adding the copolymer-modified halloysite nanotubes produced in step S1, stirring, ultrasonic treatment, adding diphenylmethane diisocyanate and organotin catalyst, reacting at 50-60°C for 8-15 hours, and allowing to stand to produce a wet gel. Step S5 includes aging the wet gel produced in step S4, controlling the aging time to 10-15 hours, adding a hydrophobic modifier to perform hydrophobic modification, drying, ball milling, and producing a modified silica aerogel powder.

[0007] Selectively, in step S1, the weight ratio of dodecyl methacrylate, pentafluorophenyl methacrylate, initiator, and halloysite nanotubes is (5-10):(2-3):(0.2-0.5):(50-80).

[0008] Selectively, in step S1, the halloysite nanotube is a coupling-modified halloysite nanotube, and the process for producing the coupling-modified halloysite nanotube includes the steps of: mixing halloysite nanotubes with a urea solution, ultrasonicating, letting stand, then adding sulfuric acid, letting stand, filtering, drying, and producing pretreated halloysite nanotubes; and adding a silane coupling agent, water, and the pretreated halloysite nanotube to a reaction vessel, adjusting the pH to 9-10, reacting at 60-80°C for 2-3 hours, adjusting the pH to neutral, cooling, filtering, washing the filtered residue, drying, and producing the coupling-modified halloysite nanotube.

[0009] Selectively, in step S1, the process for producing the pretreated halloysite nanotubes includes the steps of mixing halloysite nanotubes in a weight ratio of 1:(8~10) with a 20 wt% urea solution, sonicating, allowing to stand, then adding a 5 wt% sulfuric acid solution, allowing to stand, filtering, drying, and producing pretreated halloysite nanotubes, wherein the weight ratio of the sulfuric acid solution to the halloysite nanotubes is 5:1.

[0010] Selectively, in step S1, the process for producing the coupling-modified halloysite nanotubes includes the steps of adding a silane coupling agent, water and pre-treated halloysite nanotubes to a reaction vessel, adjusting the pH to 9-10, reacting at 60-80°C for 2-3 hours, adjusting the pH to neutral, cooling, filtering, washing the filtered residue, drying, and producing coupling-modified halloysite nanotubes, wherein the weight ratio of the silane coupling agent, water and pre-treated halloysite nanotubes is (1-1.5):100:(9-14).

[0011] By adopting the above technical proposal, urea, as a polar solvent, can help open the cavity of halloysite nanotubes, thereby enhancing the insulating capacity of halloysite nanotubes and increasing their internal surface area. Simultaneously, the insertion of urea molecules may alter the surface properties of halloysite nanotubes, potentially improving their dispersibility and reactivity. Acid treatment of halloysite nanotubes initially leads to the removal of some hydroxyl groups, but promotes re-hydroxylation of the halloysite nanotube surface, thereby generating more hydroxyl groups on the surface and providing more reaction sites for subsequent functionalization.

[0012] Selectively, in step S2, the weight ratio of silicon source, deionized water, anhydrous ethanol, and n-hexane is 1:(5~10):(3~6):(1~2).

[0013] Selectively, in step S2, the silicon source is one or more selected from methyl n-silicate, ethyl n-silicate, sodium silicate, isopropyl n-silicate, methyltrimethoxysilane, and methyltriethoxysilane.

[0014] Selectively, in step S3, the acid catalyst is one of oxalic acid solution, hydrochloric acid solution, phosphoric acid solution, and citric acid solution, with a concentration of 0.3 to 0.5 wt%.

[0015] Selectively, in step S4, the basic catalyst is one of ammonia aqueous solution, sodium carbonate solution, or sodium bicarbonate solution, with a concentration of 0.2 to 0.4 wt%.

[0016] Selectively, in step S4, the weight ratio of silica sol, copolymer-modified halloysite nanotubes, diphenylmethane diisocyanate, and organotin catalyst is (20-30):(1-3):(0.5-1):0.05.

[0017] Selectively, in step S6, the hydrophobic modifier is trimethylchlorosilane.

[0018] Selectively, in step S6, the hydrophobic modifier is a mixed liquid of n-hexane and trimethylchlorosilane in a weight ratio of (7-12):1.

[0019] By adopting the above technical proposal, using a mixture of trimethylchlorosilane and n-hexane for hydrophobic modification prevents the wet gel from reacting excessively and cleaving during the hydrophobic treatment process, thereby ensuring the surface performance of the manufactured aerogel.

[0020] Selectively, in step S5, the drying process employs freeze-vacuum drying, with a temperature of (-60) to (-30)°C, a vacuum level of 50 to 100 Pa, and a drying time of 10 to 30 hours.

[0021] By adopting the above-described technology, this invention grafts a copolymer of dodecyl methacrylate and pentafluorophenyl methacrylate onto the surface of a halloysite nanotube by copolymerization of acrylic monomers. This grafts pentafluorophenyl groups and dodecyl groups containing fluorine and benzene rings onto the surface of the halloysite nanotube. Both groups possess relatively high hydrophobicity and stability, but the long-chain alkyl structure in the dodecyl group enhances intermolecular hydrophobic interactions, thereby reducing thermal conductivity. Therefore, by copolymerizing halloysite nanotubes with dodecyl methacrylate and pentafluorophenyl methacrylate, it is possible to graft functional groups onto their surface and produce copolymer-modified halloysite nanotubes.

[0022] By adopting the above technical solution, by adding the copolymer-modified halloysite nanotubes into the silica sol after hydrolysis, the copolymer-modified halloysite nanotubes and silica gel can be bonded by Si-O-Si bonds in the basic catalyst process. At the same time, the hydroxyl groups on the silica gel surface, the hydroxyl groups on the surface of the modified halloysite nanotubes and the isocyanate groups of diphenylmethane diisocyanate can crosslink and cure to form a three-dimensional network structure, which can promote the uniform distribution of the copolymer-modified halloysite nanotubes in the silica aerogel, while further improving the mechanical properties, weather resistance and hydrophobicity of the formed composite aerogel. In addition, in the crosslinking and curing process of diphenylmethane diisocyanate, water endows the generated composite aerogel with a high porosity and a high specific surface area as a foaming agent, and diphenylmethane diisocyanate, as a curing agent containing a polybenzene ring, due to the hydrophobic effect of the benzene ring, the hydrophobicity of the produced composite aerogel is relatively high, and the hydrophobicity of the composite aerogel after hydrophobic modification is further improved, thereby finally endowing the modified silica aerogel powder with excellent water repellent effect and relatively large contact angle.

[0023] Introduce halloysite nanotubes into the silica aerogel matrix material. The halloysite nanotubes have a relatively high specific surface area, and by moving hydrophobic groups on its surface, the water repellent effect of the material can be greatly improved. The halloysite nanotubes are of a nano-sized tubular structure and have a relatively large aspect ratio. Therefore, the produced modified silica aerogel powder has good mechanical properties and heat resistance.

[0024] According to a second aspect, the present application provides a modified silica aerogel powder produced by the method for producing the above modified silica aerogel powder.

[0025] According to a third aspect, the present invention provides an aerogel slurry prepared from the above-mentioned modified silica aerogel powder, the aerogel slurry comprising the following parts by weight of raw materials: 15 to 45 parts modified silica aerogel powder, 35 to 60 parts lightweight microspheres, 250 to 350 parts aqueous inorganic resin, 5 to 10 parts sodium bentonite, 4 to 10 parts wetting agent, 4 to 8 parts dispersant, 2 to 3 parts defoaming agent, 2 to 3 parts antibacterial agent, and 400 to 550 parts water.

[0026] Selectively, the lightweight microspheres include one or more of the following: hollow glass microspheres, hollow silica microspheres, hollow ceramic microspheres, and phenolic resin hollow microspheres, the particle size of the lightweight microspheres is 100 to 350 μm, and the density of the lightweight microspheres is 0.1 to 0.4 g / cm³. 3 That is the case.

[0027] By adopting the above technical proposal, silicates in aqueous inorganic resins have relatively high permeability and can form films through petrochemical reactions with calcium ions in lightweight microspheres and carbon dioxide in the air. Furthermore, silicates in aqueous inorganic resins can form films through petrochemical reactions with aluminum ions in the aluminum-oxygen layer within halloysite nanotubes. This improves the film formation effect on the fibrous felt surface of the aerogel slurry, reduces cracking and collapse of the aerogel slurry during drying, thereby reducing the occurrence of powder and slag shedding and giving the manufactured aerogel insulating felt an excellent insulating effect.

[0028] Sodium bentonite can provide the appropriate viscosity for the application of aerogel slurry, which is advantageous for the spreading and penetration of the aerogel slurry on the fibrous felt surface. Furthermore, sodium bentonite has a relatively good thickening effect on organic resins, which can improve the sanddown resistance of the aerogel slurry, thereby further improving the uniformity of the aerogel slurry application, reducing cracking and collapse of the aerogel slurry after drying, and reducing the occurrence of powder shedding.

[0029] By adopting the above technical proposal, the aerogel slurry is an aqueous slurry, and by applying the aerogel slurry to the surface of the fiber felt, an aqueous film with excellent adhesion and leveling properties to the hydrophilic fiber felt surface is formed, making the application of the aerogel slurry more uniform and stable, and less prone to dripping. In the subsequent firing process, high-temperature treatment at 300-500°C allows for rapid evaporation of water molecules in the coating layer, which is advantageous for maintaining the overall structure of the coating layer. The coating layer can completely cover the surface of the fiber felt, thereby further improving the heat insulation capacity. At the same time, the rate of powder shedding from the aerogel heat insulating felt can be reduced. Meanwhile, the modified silica aerogel powder on the surface of the coating layer is exposed, and due to the various hydrophobic groups supported on its surface, the final aerogel heat insulating felt has an excellent water-repellent effect and a relatively large contact angle. As a result, the aerogel heat insulating felt has low thermal conductivity and can effectively block heat transfer.

[0030] According to a fourth aspect, the present application provides a method for producing the above-mentioned aerogel slurry, The process includes the steps of adding water, a dispersant, an antifoaming agent, and half an amount of wetting agent to a reaction vessel, stirring, adjusting the pH to 9-9.5, adding an aqueous inorganic resin and modified silica aerogel powder, controlling the temperature to 45-50°C, stirring, adding lightweight microspheres and sodium bentonite, stirring, adding an antimicrobial agent and the remaining wetting agent, stirring, and producing an aerogel slurry.

[0031] According to a fifth aspect, the present invention provides an application of the above-mentioned aerogel slurry in the manufacture of aerogel heat insulating felt.

[0032] Selectively, the method for producing the aerogel insulating felt includes the steps of applying an aerogel slurry to the surface of a fiber felt, allowing it to stand to stably adsorb the aerogel slurry onto the fiber felt, drying it, and producing the aerogel insulating felt.

[0033] Selectively, the fiber felt is one selected from glass fiber felt, carbon fiber felt, nickel fiber felt, stainless steel fiber felt, aluminum silicate fiber felt, ceramic fiber felt, alumina fiber felt, basalt fiber felt, and polyacrylonitrile fiber felt.

[0034] Selectively, the thickness of the fiber felt is 0.5 to 500 mm.

[0035] Selectively, the method for manufacturing the aerogel insulating felt is Step (1) involves applying an aerogel slurry to the surface of a fiber felt, allowing it to stand to stably adsorb the aerogel slurry onto the fiber felt, then drying it, and during the drying process, first by heat-insulating it at 100-150°C for 1-2 hours, and then by heat-insulating it at 300-500°C for 1-2 hours to produce a pre-treated aerogel insulating felt. The process includes step (2) of raising the pre-treated aerogel insulating felt manufactured in step (1), spraying a hydrophobic modifier from top to bottom using a spray gun, drying at 200°C, repeating the spraying once, and drying again to manufacture the aerogel insulating felt.

[0036] Selectively, the hydrophobic modifier is trimethylchlorosilane.

[0037] Selectively, the adsorption amount of aerogel slurry on the fiber felt surface is 0.5 to 500 kg / m³. 2 That is the case. [Effects of the Invention]

[0038] Based on the above, the present invention includes at least one beneficial technical effect. 1. In this invention, a composite aerogel is produced by adding copolymer-modified halloysite nanotubes to silica sol after hydrolysis, and a composite aerogel with a three-dimensional network structure, high porosity, high specific surface area, and hydrophobic groups such as pentafluorophenyl groups grafted onto the surface is obtained by the crosslinking action of diphenylmethane diisocyanate. The modified silica aerogel powder produced based on this has relatively strong water-repellent properties. In this invention, an aerogel slurry is produced from the above modified silica aerogel powder, and an aerogel insulating felt is produced by applying the aerogel slurry to the surface of a fiber felt. The aerogel insulating felt produced in this invention has low thermal conductivity and can effectively block heat transfer. The aerogel insulating felt produced in this invention has excellent temperature resistance and good mechanical properties and can be adapted to various insulating applications. 2. The modified silica aerogel powder, aerogel slurry, and aerogel insulating felt manufactured in this invention have low raw material costs, a simple manufacturing process, and easy operation, resulting in relatively low production costs. These are advantageous for industrial production and application, and have significant practical implications for the development of related industries. [Modes for carrying out the invention]

[0039] This application provides a method for producing modified silica aerogel powder. Step S1 involves adding dodecyl methacrylate, pentafluorophenyl methacrylate, an organic solvent, and halloysite nanotubes to a reaction vessel, adding an initiator, controlling the reaction temperature to 70-80°C, reacting for 4-8 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use. Step S2 involves stirring and mixing a silicon source, deionized water, anhydrous ethanol, and n-hexane at room temperature to produce a silicon source precursor solution. Step S3 involves adding an acid catalyst to the silicon source precursor solution prepared in step S2, adjusting the pH of the solution to 2-3, and carrying out a hydrolysis reaction under heating in a water bath to produce a silica sol. Step S4 involves adding a basic catalyst to the silica sol produced in step S3, adjusting the pH of the solution to 6-7, adding the copolymer-modified halloysite nanotubes produced in step S1, stirring, ultrasonic treatment, adding diphenylmethane diisocyanate and organotin catalyst, reacting at 50-60°C for 8-15 hours, and allowing to stand to produce a wet gel. Step S5 includes aging the wet gel produced in step S4, controlling the aging time to 10-15 hours, adding a hydrophobic modifier to perform hydrophobic modification, drying, ball milling, and producing a modified silica aerogel powder.

[0040] This application provides a modified silica aerogel powder produced by the above manufacturing method.

[0041] This application provides an aerogel slurry, the aerogel slurry comprising the following parts by weight of raw materials: 15-45 parts modified silica aerogel powder, 35-60 parts lightweight microspheres, 250-350 parts aqueous inorganic resin, 5-10 parts sodium bentonite, 4-10 parts wetting agent, 4-8 parts dispersant, 2-3 parts defoaming agent, 2-3 parts antibacterial agent, and 400-550 parts water.

[0042] The aerogel slurry of this invention is manufactured by employing the following method: The process includes the steps of adding water, a dispersant, an antifoaming agent, and half an amount of wetting agent to a reaction vessel, stirring, adjusting the pH to 9-9.5, adding an aqueous inorganic resin and modified silica aerogel powder, controlling the temperature to 45-50°C, stirring, adding lightweight microspheres and sodium bentonite, stirring, adding an antimicrobial agent and the remaining wetting agent, stirring, and producing an aerogel slurry.

[0043] The aerogel slurry of this invention can be applied in the field of manufacturing aerogel insulating felt.

[0044] The method for manufacturing aerogel insulating felt is: The process includes the steps of applying an aerogel slurry to the surface of a fiber felt, allowing it to stand to allow the aerogel slurry to stably adsorb onto the fiber felt, drying it, and manufacturing an aerogel insulating felt.

[0045] The technical problem solved by this invention is that composite thermal insulation felt manufactured by conventional slurry molding methods has problems such as relatively high thermal conductivity, low mechanical strength, and inability to withstand high temperatures. The modified silica aerogel manufactured in this invention has a three-dimensional network crosslinking structure, high porosity, and high specific surface area, and hydrophobic groups such as pentafluorophenyl groups are grafted onto its surface. The modified silica aerogel powder manufactured based on this has a relatively strong water-repellent effect. This invention also manufactures an aerogel slurry from the above modified silica aerogel powder and manufactures an aerogel thermal insulation felt by applying the aerogel slurry to the surface of a fiber felt. The aerogel thermal insulation felt manufactured in this invention has low thermal conductivity and can effectively block heat transfer. The aerogel thermal insulation felt manufactured in this invention has excellent temperature resistance and good mechanical properties and can be adapted to thermal insulation applications in various scenarios.

[0046] The present application will be described in more detail below in relation to specific embodiments.

[0047] (Manufacturing Example 1) The method for producing the modified silica aerogel powder in Production Example 1 is as follows: Step S1 involves adding 0.6 kg of dodecyl methacrylate, 0.25 kg of pentafluorophenyl methacrylate, 25 kg of organic solvent, and 6 kg of halloysite nanotubes to a reaction vessel, adding 0.03 kg of initiator, controlling the reaction temperature to 80°C, reacting for 6 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use. Step S2 involves mixing 1 kg of silicon source, 7 kg of deionized water, 5 kg of anhydrous ethanol, and 1.8 kg of n-hexane at room temperature with stirring to produce a silicon source precursor solution. Step S3 involves adding an acid catalyst to a silicon source precursor solution until the pH reaches 2-3, carrying out a hydrolysis reaction under heating in a water bath for 5 hours, with the water bath temperature at 70°C, in order to produce silica sol. Step S4 involves taking 26 kg of silica sol, adding a basic catalyst to adjust the pH to 6-7, then adding 2 kg of copolymer-modified halloysite nanotubes, stirring for 30 min, sonicating for 10 min, adding 0.6 kg of diphenylmethane diisocyanate and 0.05 kg of organotin catalyst, reacting at 60°C for 12 hours, and allowing to stand for 3 hours to produce a wet gel. Step S5 includes the following steps: placing the prepared wet gel in a water / anhydrous ethanol mixture in a volume ratio of 1:4, aging it at constant temperature and pressure for 12 hours under conditions of 25°C and 1 atmospheric pressure, immersing the aged wet gel in a hydrophobic modifier for hydrophobic modification for 24 hours, then freeze-drying it at a temperature of -50°C, a vacuum of 100 Pa, and a drying time of 24 hours, and ball-milling the dried modified silica aerogel until the particle size is 800 mesh to produce modified silica aerogel powder.

[0048] The halloysite nanotubes used in Production Example 1 are coupling-modified halloysite nanotubes, and the production process for these coupling-modified halloysite nanotubes is as follows: Step (1) involves mixing 6 kg of halloysite nanotubes with 60 kg of 20 wt% urea solution, ultrasonically amplified for 30 minutes, allowed to stand for 10 hours, then adding 30 kg of 5 wt% sulfuric acid solution, allowing to stand for 3 hours, filtering, drying, and producing pre-treated halloysite nanotubes. The method comprises (2) adding 0.6 kg of silane coupling agent, 50 kg of water, and 5 kg of pre-treated halloysite nanotubes to a reaction vessel, adjusting the pH to 9-10, reacting at 80°C for 2 hours, adjusting the pH to neutral, cooling, filtering, washing the filtered residue, drying, and producing coupling-modified halloysite nanotubes.

[0049] The silane coupling agent used in Manufacturing Example 1 was KH-570.

[0050] The dodecyl methacrylate used in Production Example 1 was purchased from Sigma-Aldrich, and its CAS number is 142-90-5.

[0051] The pentafluorophenyl methacrylate used in Production Example 1 was purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd., with product number P2289 and CAS number 13642-97-2.

[0052] The silicon source used in Production Example 1 was tetraethyl orthosilicate ester.

[0053] The acid catalyst used in Production Example 1 was an oxalic acid solution with a concentration of oxalic acid of 0.4 wt%, and the basic catalyst used in Production Example 1 was an aqueous ammonia solution with a concentration of aqueous ammonia of 0.4 wt%.

[0054] The organotin catalyst used in Production Example 1 is dibutyltin dilaurate.

[0055] The hydrophobic modifier in Production Example 1 consists of n-hexane and trimethylchlorosilane in a weight ratio of 8:1.

[0056] (Manufacturing example 2) The method for producing the modified silica aerogel powder in Production Example 2 is as follows: Step S1 involves adding 0.5 kg of dodecyl methacrylate, 0.3 kg of pentafluorophenyl methacrylate, 25 kg of organic solvent, and 6 kg of halloysite nanotubes to a reaction vessel, adding 0.03 kg of initiator, controlling the reaction temperature to 80°C, reacting for 6 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the modified halloysite nanotubes for use. Step S2 involves mixing 1 kg of silicon source, 7 kg of deionized water, 5 kg of anhydrous ethanol, and 1.8 kg of n-hexane at room temperature with stirring to produce a silicon source precursor solution. Step S3 involves adding an acid catalyst to a silicon source precursor solution to adjust the solution pH to 2-3, carrying out a hydrolysis reaction under heating in a water bath for 5 hours, with the water bath temperature at 70°C, in order to produce silica sol. Step S4 involves taking 26 kg of silica sol, adding a basic catalyst to adjust the solution pH to 6-7, adding 1 kg of copolymer-modified halloysite nanotubes, stirring for 30 min, ultrasonically amplified for 10 min, adding 0.5 kg of diphenylmethane diisocyanate and 0.05 kg of organotin catalyst, reacting at 60°C for 12 hours, and allowing to stand for 3 hours to produce a wet gel. Step S5 includes the following steps: placing the prepared wet gel in a water / anhydrous ethanol mixture in a volume ratio of 1:4, aging it at constant temperature and pressure for 12 hours under conditions of 25°C and 1 atmospheric pressure, immersing the aged wet gel in a hydrophobic modifier for hydrophobic modification for 24 hours, then freeze-drying it at a temperature of -50°C, a vacuum of 100 Pa, and a drying time of 24 hours, and ball-milling the dried modified silica aerogel until the particle size is 800 mesh to produce modified silica aerogel powder.

[0057] The halloysite nanotubes used in Production Example 2 are coupling-modified halloysite nanotubes, and the manufacturing process is the same as in Production Example 1.

[0058] The silicon source used in Production Example 2 is methyltrimethoxysilane, with CAS number 1185-55-3.

[0059] The acid catalyst, basic catalyst, and organotin catalyst used in Production Example 2 are the same as those used in Production Example 1.

[0060] The hydrophobic modifier in Production Example 2 consists of n-hexane and trimethylchlorosilane in a weight ratio of 12:1.

[0061] (Manufacturing Example 3) The method for producing the modified silica aerogel powder in Production Example 3 is as follows: Step S1 involves adding 1 kg of dodecyl methacrylate, 0.2 kg of pentafluorophenyl methacrylate, 25 kg of organic solvent, and 6 kg of halloysite nanotubes to a reaction vessel, adding 0.03 kg of initiator, controlling the reaction temperature to 80°C, reacting for 6 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use. Step S2 involves mixing 1 kg of silicon source, 7 kg of deionized water, 5 kg of anhydrous ethanol, and 1.8 kg of n-hexane at room temperature with stirring to produce a silicon source precursor solution. Step S3 involves adding an acid catalyst to a silicon source precursor solution until the pH reaches 2-3, carrying out a hydrolysis reaction under heating in a water bath for 5 hours, with the water bath temperature at 70°C, in order to produce silica sol. Step S4 involves taking 26 kg of silica sol, adding a basic catalyst to adjust the pH to 6-7, then adding 3 kg of copolymer-modified halloysite nanotubes, stirring for 30 min, ultrasonically amplified for 10 min, adding 1 kg of diphenylmethane diisocyanate and 0.05 kg of organotin catalyst, reacting at 60°C for 12 hours, and allowing to stand for 3 hours to produce a wet gel. Step S5 includes the following steps: placing the prepared wet gel in a water / anhydrous ethanol mixture in a volume ratio of 1:4, aging it at constant temperature and pressure for 12 hours under conditions of 25°C and 1 atmospheric pressure, immersing the aged wet gel in a hydrophobic modifier for hydrophobic modification for 24 hours, then freeze-drying at a temperature of -50°C, a vacuum of 100 Pa, and a drying time of 24 hours, and ball-milling the dried modified silica aerogel until the particle size is 800 mesh to produce modified silica aerogel powder.

[0062] The halloysite nanotubes used in Production Example 3 are coupling-modified halloysite nanotubes, and the manufacturing process is basically the same as in Production Example 1, except that the silane coupling agent used is KH-550.

[0063] The silicon source used in manufacturing example 3 was sodium silicate.

[0064] The acid catalyst, base catalyst, and organotin catalyst used in Production Example 3 are the same as those used in Production Example 1.

[0065] The hydrophobic modifier in Production Example 3 consists of n-hexane and trimethylchlorosilane in a weight ratio of 7:1.

[0066] (Manufacturing example 4) Production Example 4 is based on Production Example 1, except that the coupling-modified halloysite nanotubes used in step S2 of Production Example 4 did not undergo pretreatment with urea solution and sulfuric acid solution before reacting with the coupling agent.

[0067] (Comparative example 1) Comparative Example 1 of Manufacturing is based on Comparative Example 1, except that in Step S1, it replaces pentafluorophenyl methacrylate with the same amount of tetrafluoroethyl methacrylate.

[0068] In manufacturing comparative example 1, step S1 is: Step S1 involves adding 0.6 kg of dodecyl methacrylate, 0.25 kg of tetrafluoroethyl methacrylate, 25 kg of organic solvent, and 6 kg of halloysite nanotubes to a reaction vessel, adding 0.03 kg of initiator, controlling the reaction temperature to 80°C, reacting for 6 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use.

[0069] (Manufacturing Comparison Example 2) Comparative manufacturing example 2 is based on manufacturing example 1, except that in comparative manufacturing example 2, the halloysite nanotubes are not modified with pentafluorophenyl methacrylate in step S1.

[0070] In manufacturing comparative example 2, step S1 is: Step S1 involves adding 0.6 kg of dodecyl methacrylate, 25 kg of organic solvent, and 6 kg of halloysite nanotubes to a reaction vessel, adding 0.03 kg of initiator, controlling the reaction temperature to 80°C, reacting for 6 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use.

[0071] (Comparative example 3 of manufacturing) Comparative manufacturing example 3 is based on manufacturing example 1, except that in step S1, dodecyl methacrylate is replaced with the same amount of n-butyl methacrylate.

[0072] In manufacturing comparative example 3, step S1 is: Step S1 involves adding 0.6 kg of n-butyl methacrylate, 0.25 kg of pentafluorophenyl methacrylate, 25 kg of organic solvent, and 6 kg of halloysite nanotubes to a reaction vessel, adding 0.03 kg of initiator, controlling the reaction temperature to 80°C, reacting for 6 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use.

[0073] (Manufacturing Comparison Example 4) Comparative manufacturing example 4 is based on manufacturing example 1, except that in comparative manufacturing example 4, the halloysite nanotubes are not modified with dodecyl methacrylate in step S1.

[0074] In manufacturing comparative example 4, step S1 is: Step S1 involves adding 0.25 kg of pentafluorophenyl methacrylate, 25 kg of organic solvent, and 6 kg of halloysite nanotubes to a reaction vessel, adding 0.03 kg of initiator, controlling the reaction temperature to 80°C, reacting for 6 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use.

[0075] (Examples 1-3) Examples 1-3 are different aerogel slurries that were manufactured, differing in the proportions of the raw materials used, specifically as follows:

[0076] The aerogel slurry produced in Example 1 consisted of the following parts by weight of raw materials: This product contains 38 parts of modified silica aerogel powder, 45 parts of lightweight microspheres, 280 parts of aqueous inorganic resin, 8 parts of sodium bentonite, 6 parts of wetting agent, 6 parts of dispersant, 2.5 parts of defoaming agent, 2.5 parts of antibacterial agent, and 500 parts of water.

[0077] The aerogel slurry produced in Example 2 consisted of the following parts by weight of raw materials: This product contains 15 parts of modified silica aerogel powder, 60 parts of lightweight microspheres, 250 parts of aqueous inorganic resin, 5 parts of sodium bentonite, 10 parts of wetting agent, 4 parts of dispersant, 2 parts of defoaming agent, 2 parts of antibacterial agent, and 400 parts of water.

[0078] The aerogel slurry produced in Example 3 consisted of the following parts by weight of raw materials: It contains 45 parts of modified silica aerogel powder, 35 parts of lightweight microspheres, 350 parts of aqueous inorganic resin, 10 parts of sodium bentonite, 4 parts of wetting agent, 8 parts of dispersant, 3 parts of defoaming agent, 3 parts of antibacterial agent, and 550 parts of water.

[0079] The modified silica aerogel powders used in Examples 1 to 3 were all produced in Production Example 1.

[0080] The lightweight microspheres used in Examples 1-3 were hollow ceramic microspheres with an average particle size of 150 μm and an average density of 0.3 g / cm³. 3 That is the case.

[0081] The aqueous inorganic resins used in Examples 1-3 were lithium silicate resins purchased from Tianjin Fo-Dou New Materials, with a module (alkali silicate ratio) of 4.8±0.1, an SiO2 content of 19.0-21.0 wt%, and a Li2O content of 2.0-2.2 wt%.

[0082] The wetting agent used in Examples 1-3 was METALAT® 514, manufactured by Munzing Chemicals GmbH in Germany.

[0083] The dispersant used in Examples 1-3 was EDAPLAN 490, manufactured by Munzing Chemicals GmbH in Germany.

[0084] The defoaming agent used in Examples 1-3 was AGITAN® 299, manufactured by Munzing Chemicals GmbH in Germany.

[0085] The antibacterial agent used in Examples 1-3 is oxobiphenoxine, an industrial antifungal agent No. 75.

[0086] The manufacturing process for Examples 1-3 is as follows: The process includes the steps of adding water, a dispersant, an antifoaming agent, and half an amount of wetting agent to a reaction vessel, stirring for 5 minutes to adjust the pH to 9-9.5, adding an aqueous inorganic resin and modified silica aerogel powder, controlling the temperature to 45°C, stirring for 30 minutes, adding lightweight microspheres and sodium bentonite, stirring for 5 minutes, adding an antimicrobial agent and the remaining wetting agent, stirring for 5 minutes, and producing an aerogel slurry.

[0087] Examples 4-5 Example 4 is based on Example 1, except that the amount of modified silica aerogel powder used in Example 4 is changed from 38 parts to 15 parts.

[0088] Example 5 is based on Example 1, except that the amount of modified silica aerogel powder used in Example 5 is changed from 38 parts to 45 parts.

[0089] (Examples 6-8 and Comparative Examples 1-2) Examples 6-8 and Comparative Examples 1-2 are based on Example 1, except that the modified silica aerogel powder used in Examples 6-8 and Comparative Examples 1-2 is different; see Table 1 for details.

[0090] [Table 1]

[0091] (Comparative Example 5) Comparative Example 5 is based on Example 1, except that in Comparative Example 5, the modified silica aerogel powder in the raw materials is replaced with commercially available silica aerogel powder, and the material is Wacker H15 type fume silica from Germany.

[0092] (Application Examples 1-8) Application Examples 1 to 8 are aerogel insulating felts manufactured using the aerogel slurries produced in Examples 1 to 8, respectively, and the aerogel slurries used in Application Examples 1 to 8 correspond sequentially to Examples 1 to 8.

[0093] The manufacturing method for aerogel insulating felt in application examples 1 to 8 is as follows: A 5mm thick glass fiber felt was scraped using an aerogel slurry, and then allowed to stand to allow the aerogel slurry to stably adsorb onto the fiber felt. After drying, it was first heated at 150°C for 1 hour, and then heated at 200°C for 2 hours to produce aerogel insulating felt. The amount of aerogel slurry adsorbed on the surface of the fiber felt was 4 kg / m². 2 This includes a step of controlling it.

[0094] The density of the glass fiber felt used in application examples 1-8 was 0.2 g·cm³. -3 That is the case.

[0095] (Application Example 9) Application Example 9 describes the manufacturing method for Application Example 9, A 5mm thick glass fiber felt was scraped using an aerogel slurry, and the felt was left to stand to allow the aerogel slurry to stably adsorb onto it. After drying, it was first heated at 150°C for 1 hour, and then heated at 200°C for 2 hours to produce a pre-treated aerogel insulating felt. The amount of aerogel slurry adsorbed on the surface of the fiber felt was 4 kg / m². 2 Step (1) to control, Step (1) involves raising the pre-treated aerogel insulation felt, spraying a hydrophobic modifier from top to bottom using a spray gun, drying at 200°C, repeating the spraying once more, and drying again, thereby producing aerogel insulation felt, wherein the hydrophobic modifier is trimethylchlorosilane and the amount sprayed per application is 40 g / m². 2 Except for step (2), which is included, this is based on Application Example 1.

[0096] (Application Comparison Example 1) Comparative Example 1 of Application is based on Comparative Example 1, except that the aerogel slurry in Comparative Example 1 is the same aerogel slurry produced in Comparative Example 1.

[0097] (Example of application 2) Comparative Example 2 of Application is based on Comparative Example 1, except that the aerogel slurry in Comparative Example 2 is the same aerogel slurry produced in Comparative Example 2.

[0098] (Example of application 3) Comparative Example 3 is based on Comparative Example 1, except that the aerogel slurry in Comparative Example 3 is the aerogel slurry manufactured in Comparative Example 3.

[0099] (Example of Application 4) Comparative Example 4 is based on Comparative Example 1, except that the aerogel slurry in Comparative Example 4 is the same aerogel slurry produced in Comparative Example 4.

[0100] (Example of application 5) Comparative Example 5 is based on Comparative Example 1, except that the aerogel slurry in Comparative Example 5 is the aerogel slurry manufactured in Comparative Example 5.

[0101] Performance detection 1. Referring to the standard GB / T 10295-2008 "Measurement of Steady Thermal Resistance and Related Properties of Thermal Insulation Materials - Heat Flow Meter Method", the thermal conductivity (W / (m·K)) of the aerogel thermal insulation felt manufactured in Application Examples 1-9 and Application Comparative Examples 1-5 at 25°C was measured, and the measurement results are shown in Table 2. 2. The compressive strength (MPa) of the aerogel thermal insulation felt manufactured in Application Examples 1-9 and Application Comparative Examples 1-5 was measured, and the measurement results are shown in Table 2. 3. Referring to the standard GB 34336-2017 "Standard for Nano-Aerogel Composite Thermal Insulation Articles", the powder shedding rate (%) of the aerogel thermal insulation felt manufactured in Application Examples 1-9 and Application Comparative Examples 1-5 was measured, and the measurement results are shown in Table 2. 4. Aerogel thermal insulation felt quench resistance test: Using a NexGen oil burner, at a temperature of 1009-1036°C, for each application example, two pieces of aerogel thermal insulation felt on the left and right were used as samples, the thickness was controlled to 10 mm, the same side of the samples was fired for 30 minutes, the presence or absence of quenching after firing was observed, and the maximum heat flux (W / cm 2 ) and the occurrence time (s) from the back surface to the front surface of 305 mm of the two pieces of aerogel thermal insulation felt on the left and right were measured. The quench resistance test was carried out for Application Example 3, Application Example 5, and Application Example 9 respectively, and the measurement results are shown in Table 3. (The evaluation criterion is that the maximum heat flux from the back surface to the front surface of 305 mm of the thermal insulation felt shall not exceed 2.27 W / cm 2 )

[0102]

Table 2

[0103]

Table 3

[0104] Analysis of the data in Table 2 shows that the aerogel insulating felt manufactured in this invention has a low thermal conductivity of 0.014 W / (m·K) at 25°C. This indicates that the aerogel insulating felt manufactured in this invention has extremely low thermal conductivity and can effectively block heat transfer. Comparing Application Example 1 with Application Comparative Examples 1 and 2, it was found that the thermal conductivity of the aerogel insulating felt manufactured using tetrafluoroethyl methacrylate instead of pentafluorophenyl methacrylate increased significantly, its insulating capacity was significantly weakened, and the powder shedding rate also increased significantly. This indicates that pentafluorophenyl methacrylate has a significant effect on controlling the hydrophobicity of the modified silica aerogel powder and aerogel insulating felt. Furthermore, it is advantageous for improving the insulating capacity of the aerogel insulating felt and for the rapid removal of moisture from the aerogel insulating felt coating layer during firing, thus maintaining the structural integrity of the aerogel insulating felt coating layer and reducing the occurrence of powder shedding. Comparing Application Example 1 with Application Comparative Examples 3 and 4, it can be seen that while using long-chain alkyl methacrylate improves the hydrophobicity of the modified silica aerogel powder to some extent, the effect of improving the hydrophobicity of the modified silica aerogel powder is lower compared to pentafluorophenyl methacrylate.

[0105] Analysis of the data in Table 3 reveals that the aerogel insulation felt manufactured in this invention exhibits excellent heat resistance, heat insulation, and fire resistance, making it suitable for use in various fire protection facilities, insulation facilities, and fire protection scenarios. Furthermore, the aerogel insulation felt manufactured in this invention has high mechanical strength, minimal powder shedding, and can be applied to a variety of insulation scenarios.

[0106] All of the above are preferred embodiments of the present application and do not limit the scope of protection; therefore, all equivalent modifications made by the structure, shape, and principle of the present application should be included within the scope of protection.

Claims

1. A method for producing modified silica aerogel powder, Step S1 involves adding dodecyl methacrylate, pentafluorophenyl methacrylate, an organic solvent, and halloysite nanotubes to a reaction vessel, adding an initiator, controlling the reaction temperature to 70-80°C, reacting for 4-8 hours with stirring, cooling, filtering, removing the filtration residue, washing, drying, and preparing the copolymer-modified halloysite nanotubes for use. Step S2 involves stirring and mixing a silicon source, deionized water, anhydrous ethanol, and n-hexane at room temperature to produce a silicon source precursor solution. Step S3 involves adding an acid catalyst to the silicon source precursor solution prepared in step S2, adjusting the pH of the solution to 2-3, and carrying out a hydrolysis reaction under heating in a water bath to produce a silica sol. Step S4 involves adding a basic catalyst to the silica sol produced in step S3, adjusting the pH of the solution to 6-7, adding the copolymer-modified halloysite nanotubes produced in step S1, stirring, ultrasonic treatment, adding diphenylmethane diisocyanate and organotin catalyst, reacting at 50-60°C for 8-15 hours, and allowing to stand to produce a wet gel. A method for producing modified silica aerogel powder, comprising step S5, which involves aging the wet gel produced in step S4, controlling the aging time to 10 to 15 hours, adding a hydrophobic modifier to perform hydrophobic modification, drying, ball milling, and producing modified silica aerogel powder.

2. The method for producing modified silica aerogel powder according to claim 1, characterized in that, in step S1, the halloysite nanotube is a coupling-modified halloysite nanotube, and the process for producing the coupling-modified halloysite nanotube includes the steps of: mixing halloysite nanotube with a urea solution, ultrasonicating, letting stand, then adding sulfuric acid, letting stand, filtering, drying, and producing pretreated halloysite nanotube; and adding a silane coupling agent, water, and the pretreated halloysite nanotube to a reaction vessel, adjusting the pH to 9-10, reacting at 60-80°C for 2-3 hours, adjusting the pH to neutral, cooling, filtering, washing the filtered residue, drying, and producing coupling-modified halloysite nanotube.

3. The method for producing modified silica aerogel powder according to claim 1, characterized in that, in step S3, the acid catalyst is one of oxalic acid solution, hydrochloric acid solution, phosphoric acid solution, and citric acid solution, with a concentration of 0.3 to 0.5 wt%, and in step S4, the basic catalyst is one of ammonia aqueous solution, sodium carbonate solution, and sodium bicarbonate solution, with a concentration of 0.2 to 0.4 wt%.

4. The method for producing modified silica aerogel powder according to claim 1, characterized in that, in step S5, the hydrophobic modifier is trimethylchlorosilane.

5. Modified silica aerogel powder produced by the method for producing modified silica aerogel powder according to any one of claims 1 to 4.

6. The aerogel slurry produced using the modified silica aerogel powder according to claim 5 is characterized in that the aerogel slurry contains the following parts by weight of raw materials: 15 to 45 parts modified silica aerogel powder, 35 to 60 parts lightweight microspheres, 250 to 350 parts aqueous inorganic resin, 5 to 10 parts sodium bentonite, 4 to 10 parts wetting agent, 4 to 8 parts dispersant, 2 to 3 parts defoaming agent, 2 to 3 parts antibacterial agent, and 400 to 550 parts water.

7. The method for producing an aerogel slurry according to claim 6, comprising the steps of adding water, a dispersant, an antifoaming agent, and half an amount of wetting agent to a reaction vessel, stirring, adjusting the pH to 9 to 9.5, adding an aqueous inorganic resin and modified silica aerogel powder, controlling the temperature to 45 to 50°C, stirring, adding lightweight microspheres, stirring, adding an antimicrobial agent and the remaining wetting agent, stirring, and producing an aerogel slurry.

8. Use of the aerogel slurry according to claim 7 in the manufacture of an aerogel insulating felt.

9. The method for manufacturing the aerogel insulating felt includes the steps of applying an aerogel slurry to the surface of a fiber felt, allowing it to stand to stably adsorb the aerogel slurry onto the fiber felt, drying it, and manufacturing the aerogel insulating felt. The fiber felt is selected from glass fiber felt, carbon fiber felt, nickel fiber felt, stainless steel fiber felt, aluminum silicate fiber felt, ceramic fiber felt, alumina fiber felt, basalt fiber felt, and polyacrylonitrile fiber felt, and the thickness of the fiber felt is 0.5 to 500 mm. The amount of aerogel slurry adsorbed on the fiber felt surface is 0.5 to 50 kg / m². ２ The use of aerogel slurry in the manufacture of an aerogel insulating felt according to the feature of 8.

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