Aerogel blanket and method of making same

Abstract

The application discloses an aerogel felt and a manufacturing method thereof, relates to the technical field of aerogel felt, and the manufacturing method of the aerogel felt comprises the following steps: S1, substrate fixing: the two sides of a substrate are constrained through a slit, and the substrate is fixed straight above silica aerogel powder; S2, powder feeding: silica aerogel powder is added to the surface of the substrate, and the silica aerogel powder on the surface of the aerogel felt is scraped flat; S3, powder fixing: the silica aerogel powder is shuttled and fixed in the substrate by a physical method; S4, powder cleaning: the excess silica aerogel powder on the surface of the substrate is cleaned; and S5, surface coating: silane adhesive is applied to the upper and lower surfaces of the substrate, and the substrate is heated to 110-115 DEG C and cured for 10-12 h to obtain the aerogel felt.

Description

Technical Field

[0001] This invention relates to the field of aerogel felt technology, specifically an aerogel felt and its manufacturing method. Background Technology

[0002] Aerogel felt, as a typical high-efficiency porous thermal insulation material, has irreplaceable application value in fields such as building energy conservation, thermal management of new energy power batteries, thermal insulation of aerospace equipment and thermal insulation of industrial kilns due to its strong inhibition of heat conduction (solid conduction and gas convection conduction) by its nanoscale porous structure. Its core technical indicators focus on low thermal conductivity and long-term high temperature stability.

[0003] However, existing aerogel felts still face significant bottlenecks in performance optimization and practical applications: In terms of thermal insulation performance, traditional manufacturing processes often suffer from incomplete development of the mesoporous structure of the aerogel due to improper control of key parameters (such as imbalance in the amount of phase transfer agent during the synthesis of silica aerogel powder and poor bonding between the substrate and the aerogel powder). This results in either a large number of mesopores collapsing and a decrease in mesopority, or excessive residual silanol groups causing gel shrinkage, ultimately leading to increased material density and thermal conductivity (the thermal conductivity of most products is difficult to stably fall below 0.020 W / (m·K)), failing to meet the requirements of high-precision thermal insulation scenarios (such as electronic components and aerospace cabins). At the same time, some aerogel felts are prone to powder shedding due to weak interfacial bonding between the substrate (such as ordinary fiber felt) and the aerogel powder, further disrupting the continuity of the thermal insulation structure and causing a decrease in thermal insulation performance.

[0004] In terms of high-temperature resistance, the shortcomings of existing products are more prominent: on the one hand, the substrate (such as unmodified polyacrylonitrile fiber felt) is prone to thermal aging, structural embrittlement, or even ablation at temperatures above 600°C, losing its support for the aerogel powder; on the other hand, the adhesive layer coated on the surface mostly relies on a single organic or inorganic component, lacking a composite protective structure that can exist stably at high temperatures. If it is an organic adhesive, it is easy to decompose and carbonize at high temperatures, failing to form an effective heat insulation barrier; if it is a simple inorganic adhesive, it is difficult to form a synergistic effect with the substrate and aerogel powder, resulting in rapid heat penetration of the material when exposed to flames above 800°C, with the back temperature often exceeding 350°C, and even the overall failure of the material.

[0005] Furthermore, while existing technologies offer improvements for single properties (such as thermal insulation or high-temperature resistance) (e.g., using high-pressure drying to enhance mesoporous integrity or adding high-temperature resistant fillers to improve the substrate's heat resistance), they generally suffer from complex processes, high production costs, and difficulties in large-scale production. This makes it difficult to simultaneously achieve synergistic optimization of "low thermal conductivity" and "high high-temperature stability," failing to meet the urgent industrial demand for efficient, reliable, and low-cost thermal insulation materials. Therefore, overcoming the technological bottlenecks in the synergistic improvement of thermal insulation and high-temperature resistance performance of aerogel felts has become the core research direction in this field. Summary of the Invention

[0006] The purpose of this invention is to provide an aerogel felt and a method for manufacturing the same, in order to solve the problems raised in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for manufacturing an aerogel felt includes the following steps:

[0009] S1: Substrate fixing: The two sides of the substrate are constrained by slits and stretched and fixed above the silica aerogel powder;

[0010] S2: Powder feeding: Add silica aerogel powder to the surface of the substrate and scrape the silica aerogel powder on the surface of the aerogel felt.

[0011] S3: Powder fixation: Silica aerogel powder is physically inserted and fixed inside the substrate;

[0012] S4: Powder cleaning: Clean excess silica aerogel powder from the substrate surface;

[0013] S5: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110-115℃ and cure for 10-12 hours to obtain aerogel felt.

[0014] Furthermore, the slit dimensions are 0.5-5mm in height and 2-10mm in width;

[0015] Furthermore, the straightening method is achieved by moving the substrate 0.1-2 mm toward the slit side;

[0016] Furthermore, the distance between the substrate and the silica aerogel powder is 0-5 mm;

[0017] Furthermore, the physical method includes any one of mechanical oscillation, electrostatic field, alternating electric field, and physical compression;

[0018] Furthermore, the coating amount of the silane adhesive is 400-500 g / m². 2 .

[0019] Furthermore, the method for preparing the substrate includes the following steps:

[0020] Tetraethyl orthosilicate, deionized water, and ethanol were added to a reaction vessel and stirred until homogeneous. A 1 mol / L phosphoric acid catalyst was added, and the mixture was heated to 50-55°C for 6-6.5 h to obtain a silica sol. Fiber felt was impregnated in the silica sol, and 1 mol / L ammonia and anhydrous ethanol were added. The mixture was heated to 50-55°C and aged for 24 h to obtain a composite gel. The composite gel was placed in a mixed solution of hexane and trimethylchlorosilane and modified for 24 h to obtain a modified composite gel. The modified composite gel was then subjected to combustion drying to obtain the substrate.

[0021] Furthermore, in the preparation process of the silica sol, the molar ratio of tetraethyl orthosilicate:deionized water:ethanol is 1:(4-5):(4-5); in the mixed solution of n-hexane and trimethylchlorosilane, the volume ratio of n-hexane:trimethylchlorosilane is 6:(1-2).

[0022] Furthermore, the method for preparing the silica aerogel powder includes the following steps:

[0023] Sodium silicate solution was diluted to a SiO2 concentration of 4.5-5 wt% to obtain a silicon source precursor. The silicon source precursor was added to a reaction vessel and preheated to 65-66℃. Heptane and hexamethyldisilazane were added sequentially under stirring and stirred until homogeneous. 70% nitric acid catalyst was added and the reaction was stirred for 30-35 min. Phase transfer agent was added and the reaction was stirred for 1-1.5 h. After standing, the aqueous phase was removed. The organic phase slurry was placed in an environment of 150-155℃ and dried under normal pressure to obtain silica aerogel powder.

[0024] Furthermore, in the preparation process of the silica aerogel powder, the volume ratio of silicon source precursor: heptane: hexamethyldisilazane: nitric acid catalyst: phase transfer agent is 50:60:6:4:(2-4).

[0025] Furthermore, the preparation method of the silane adhesive includes the following steps: Step (1): 3-aminopropylmethyldiethoxysilane is added to deionized water and heated in a gradient manner. The mixture is heated to 90-95℃ for 6-6.5h, heated to 120-125℃ under vacuum for 3-3.5h, and heated to 150-155℃ under vacuum for 3-3.5h to obtain hydrolyzed polycondensed silane;

[0026] Step (2): Add the ethanol solution of hydrolyzed polysilane to the ethanol solution of diphenyl phosphate, stir evenly, heat to 70-75℃ and react for 12-16 h, then dry by rotary evaporation to obtain modified silane.

[0027] Step (3): Add the modified silane to the isopropanol solution of boric acid, heat to 75-78℃ and react for 30-35 minutes, then heat to 105-106℃ to remove the solvent and obtain silane adhesive.

[0028] Furthermore, in the preparation process of the hydrolyzed polysilane, the mass ratio of 3-aminopropylmethyldiethoxysilane to deionized water is (20.3-21.6):5.4.

[0029] Furthermore, the phase transfer agent is either ethanol or propanol.

[0030] Furthermore, in the preparation process of the modified silane, the mass ratio of hydrolyzed polycondensed silane to diphenyl phosphate is 5:(10.4-12.6).

[0031] Furthermore, in the preparation process of the silane adhesive, the mass ratio of modified silane to boric acid is 1.5:(1-1.5).

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. This invention achieves a balance of "high mesopority - low collapse" in mesoporous structure by controlling the amount of phase transfer agent (ethanol / propanol). The phase transfer agent can reduce the interfacial tension between water (aqueous phase) and heptane (organic phase), promote the diffusion of hexamethyldisilazane (hydrophobic agent) into the gel interior, and form a porous structure. This structure can significantly reduce solid-state heat conduction, while restricting the movement of gas molecules in the pores, inhibiting gas convection heat conduction, and greatly improving the thermal insulation performance of aerogel felt.

[0034] 2. The skeleton of the pre-oxidized PAN fiber felt is impregnated with silica sol, modified with n-hexane-trimethylchlorosilane and dried by combustion to form a composite morphology of "fiber skeleton-aerogel encapsulation". The Si-O-Si bonds on the fiber surface are tightly combined with the aerogel powder to construct a continuous "porous skeleton" network. There are no macroscopic airflow channels, which blocks macroscopic heat convection and greatly improves the high temperature resistance.

[0035] 3. Phosphorus-boron-silicon synergy in silane adhesives to construct a ceramic phase: Diphenyl phosphate ester (phosphorus source) and boric acid (boron source) in silane adhesives undergo a synergistic reaction at high temperatures. The phosphate groups (-PO4) promote the dehydration and carbonization of organic components, forming a dense carbon layer. Boric acid decomposes to generate a B2O3 glass phase, which reacts with the phosphate ester to form a high-temperature resistant BPO ceramic phase, preventing rapid heat conduction and greatly improving thermal insulation and high-temperature resistance. The Si-O-Si bonds in silane are reconstructed into a dense SiO2 layer at high temperatures, which combines with the BPO ceramic to form a "ceramic phase-SiO2-carbon layer" composite barrier, further enhancing high-temperature resistance. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the following examples, the fiber felt has the following parameters: thickness of 2 mm and density of 0.15 g / cm³. 3 The raw materials were purchased from Shaanxi Huate; the rest were commercially available.

[0038] The method for preparing the substrate includes the following steps:

[0039] 1 mmol tetraethyl orthosilicate, 4 mmol deionized water, and 4 mmol ethanol were added to a reaction vessel and stirred until homogeneous. 1 mol / L phosphoric acid catalyst was added, and the mixture was heated to 50°C for 6 h to obtain silica sol. Fiber felt was impregnated in silica sol, 1 mol / L ammonia water and anhydrous ethanol were added, and the mixture was heated to 50-55°C for 24 h to obtain composite gel. The composite gel was placed in a mixed solution of 6 mL n-hexane and 1 mL trimethylchlorosilane and modified for 24 h to obtain modified composite gel. The modified composite gel was then subjected to combustion drying to obtain the substrate.

[0040] The preparation method of silane adhesive includes the following steps: Step (1): 20.3g of 3-aminopropylmethyldiethoxysilane is added to 5.4g of deionized water and heated in a gradient. The reaction is carried out at 90°C for 6 hours, at 120°C under vacuum for 3 hours, and at 150°C under vacuum for 3 hours to obtain hydrolyzed polysilane.

[0041] Step (2): Add 5g of hydrolyzed polysilane ethanol solution to 10.4g of diphenyl phosphate ethanol solution, stir evenly, heat to 70℃ and react for 12h, then dry by rotary evaporation to obtain modified silane.

[0042] Step (3): Add 1.5g of modified silane to a solution of 1g boric acid in isopropanol, heat to 75℃ and react for 30min, then heat to 105℃ to remove the solvent to obtain silane adhesive.

[0043] Example 1: A method for manufacturing an aerogel felt, comprising the following steps:

[0044] S1: Dilute sodium silicate solution to SiO2 concentration of 4.5wt% to obtain silicon source precursor; add 50mL of silicon source precursor to reaction vessel, preheat to 65℃, add 60mL of heptane and 6mL of hexamethyldisilazane in sequence while stirring, stir evenly, add 4mL of 70% nitric acid catalyst, stir and react for 30min, add 2mL of ethanol, stir and react for 1h, let stand, remove aqueous phase, place organic phase slurry in 150℃ environment and dry under normal pressure to obtain silica aerogel powder.

[0045] S2: Substrate fixing: The substrate is constrained on both sides by slits and tautly fixed above the silica aerogel powder;

[0046] S3: Powder feeding: Add silica aerogel powder to the surface of the substrate and smooth the silica aerogel powder on the surface of the aerogel felt.

[0047] S4: Powder fixation: An electrostatic field is used to shuttle and fix silica aerogel powder inside the substrate;

[0048] S5: Powder Cleaning: Clean excess silica aerogel powder from the substrate surface;

[0049] S6: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110℃ and cure for 10 hours to obtain aerogel felt.

[0050] The slit dimensions are 1mm high and 8mm wide;

[0051] The straightening method is achieved by moving the substrate 0.5 mm toward the slit side;

[0052] The distance between the substrate and the silica aerogel powder is 1 mm;

[0053] The silane adhesive coating amount is 500 g / m². 2 .

[0054] Example 2: A method for manufacturing an aerogel felt, comprising the following steps:

[0055] S1: Dilute sodium silicate solution to SiO2 concentration of 4.5wt% to obtain silicon source precursor; add 50mL of silicon source precursor to reaction vessel, preheat to 65℃, add 60mL of heptane and 6mL of hexamethyldisilazane in sequence while stirring, stir evenly, add 4mL of 70% nitric acid catalyst, stir and react for 30min, add 3mL of ethanol, stir and react for 1h, let stand, remove aqueous phase, place organic phase slurry in 150℃ environment and dry under normal pressure to obtain silica aerogel powder.

[0056] S2: Substrate fixing: The substrate is constrained on both sides by slits and tautly fixed above the silica aerogel powder;

[0057] S3: Powder feeding: Add silica aerogel powder to the surface of the substrate and smooth the silica aerogel powder on the surface of the aerogel felt.

[0058] S4: Powder fixation: An electrostatic field is used to shuttle and fix silica aerogel powder inside the substrate;

[0059] S5: Powder Cleaning: Clean excess silica aerogel powder from the substrate surface;

[0060] S6: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110℃ and cure for 10 hours to obtain aerogel felt.

[0061] The slit dimensions are 1mm high and 8mm wide;

[0062] The straightening method is achieved by moving the substrate 0.5 mm toward the slit side;

[0063] The distance between the substrate and the silica aerogel powder is 1 mm;

[0064] The silane adhesive coating amount is 500 g / m². 2 .

[0065] Example 3: A method for manufacturing an aerogel felt, comprising the following steps:

[0066] S1: Dilute sodium silicate solution to SiO2 concentration of 4.5wt% to obtain silicon source precursor; add 50mL of silicon source precursor to reaction vessel, preheat to 65℃, add 60mL of heptane and 6mL of hexamethyldisilazane in sequence while stirring, stir evenly, add 4mL of 70% nitric acid catalyst, stir and react for 30min, add 4mL of ethanol, stir and react for 1h, let stand, remove aqueous phase, place organic phase slurry in 150℃ environment and dry under normal pressure to obtain silica aerogel powder.

[0067] S2: Substrate fixing: The substrate is constrained on both sides by slits and tautly fixed above the silica aerogel powder;

[0068] S3: Powder feeding: Add silica aerogel powder to the surface of the substrate and smooth the silica aerogel powder on the surface of the aerogel felt.

[0069] S4: Powder fixation: An electrostatic field is used to shuttle and fix silica aerogel powder inside the substrate;

[0070] S5: Powder Cleaning: Clean excess silica aerogel powder from the substrate surface;

[0071] S6: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110℃ and cure for 10 hours to obtain aerogel felt.

[0072] The slit dimensions are 1mm high and 8mm wide;

[0073] The straightening method is achieved by moving the substrate 0.5 mm toward the slit side;

[0074] The distance between the substrate and the silica aerogel powder is 1 mm;

[0075] The silane adhesive coating amount is 500 g / m². 2 .

[0076] Comparative Example 1: A method for manufacturing an aerogel felt, comprising the following steps:

[0077] S1: Dilute sodium silicate solution to SiO2 concentration of 4.5wt% to obtain silicon source precursor; add 50mL of silicon source precursor to reaction vessel, preheat to 65℃, add 60mL of heptane and 6mL of hexamethyldisilazane in sequence while stirring, stir evenly, add 4mL of 70% nitric acid catalyst, stir and react for 30min, add 0.5mL of ethanol, stir and react for 1h, let stand, remove aqueous phase, place organic phase slurry in 150℃ environment and dry under normal pressure to obtain silica aerogel powder.

[0078] S2: Substrate fixing: The substrate is constrained on both sides by slits and tautly fixed above the silica aerogel powder;

[0079] S3: Powder feeding: Add silica aerogel powder to the surface of the substrate and smooth the silica aerogel powder on the surface of the aerogel felt.

[0080] S4: Powder fixation: An electrostatic field is used to shuttle and fix silica aerogel powder inside the substrate;

[0081] S5: Powder Cleaning: Clean excess silica aerogel powder from the substrate surface;

[0082] S6: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110℃ and cure for 10 hours to obtain aerogel felt.

[0083] The slit dimensions are 1mm high and 8mm wide;

[0084] The straightening method is achieved by moving the substrate 0.5 mm toward the slit side;

[0085] The distance between the substrate and the silica aerogel powder is 1 mm;

[0086] The silane adhesive coating amount is 500 g / m².2 .

[0087] Comparative Example 2: A method for manufacturing an aerogel felt, comprising the following steps:

[0088] S1: Dilute sodium silicate solution to SiO2 concentration of 4.5wt% to obtain silicon source precursor; add 50mL of silicon source precursor to reaction vessel, preheat to 65℃, add 60mL of heptane and 6mL of hexamethyldisilazane in sequence while stirring, stir evenly, add 4mL of 70% nitric acid catalyst, stir and react for 30min, add 6mL of ethanol, stir and react for 1h, let stand, remove aqueous phase, place organic phase slurry in 150℃ environment and dry under normal pressure to obtain silica aerogel powder.

[0089] S2: Substrate fixing: The substrate is constrained on both sides by slits and tautly fixed above the silica aerogel powder;

[0090] S3: Powder feeding: Add silica aerogel powder to the surface of the substrate and smooth the silica aerogel powder on the surface of the aerogel felt.

[0091] S4: Powder fixation: An electrostatic field is used to shuttle and fix silica aerogel powder inside the substrate;

[0092] S5: Powder Cleaning: Clean excess silica aerogel powder from the substrate surface;

[0093] S6: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110℃ and cure for 10 hours to obtain aerogel felt.

[0094] The slit dimensions are 1mm high and 8mm wide;

[0095] The straightening method is achieved by moving the substrate 0.5 mm toward the slit side;

[0096] The distance between the substrate and the silica aerogel powder is 1 mm;

[0097] The silane adhesive coating amount is 500 g / m². 2 .

[0098] Comparative Example 3: A method for manufacturing an aerogel felt, comprising the following steps:

[0099] S1: Dilute sodium silicate solution to SiO2 concentration of 4.5wt% to obtain silicon source precursor; add 50mL of silicon source precursor to reaction vessel, preheat to 65℃, add 60mL of heptane and 6mL of hexamethyldisilazane in sequence while stirring, stir evenly, add 4mL of 70% nitric acid catalyst, stir and react for 30min, add 2mL of ethanol, stir and react for 1h, let stand, remove aqueous phase, place organic phase slurry in 150℃ environment and dry under normal pressure to obtain silica aerogel powder.

[0100] S2: Substrate fixing: The substrate is constrained on both sides by slits and tautly fixed above the silica aerogel powder;

[0101] S3: Powder feeding: Add silica aerogel powder to the surface of the substrate and smooth the silica aerogel powder on the surface of the aerogel felt.

[0102] S4: Powder fixation: An electrostatic field is used to shuttle and fix silica aerogel powder inside the substrate;

[0103] S5: Powder Cleaning: Clean excess silica aerogel powder from the substrate surface;

[0104] S6: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110℃ and cure for 10 hours to obtain aerogel felt.

[0105] The slit dimensions are 1mm high and 8mm wide;

[0106] The straightening method is achieved by moving the substrate 0.5 mm toward the slit side;

[0107] The distance between the substrate and the silica aerogel powder is 1 mm;

[0108] The silane adhesive coating amount is 500 g / m². 2 ;

[0109] The preparation method of silane adhesive includes the following steps: Step (1): 20.3g of 3-aminopropylmethyldiethoxysilane is added to 5.4g of deionized water and heated in a gradient. The reaction is carried out at 90°C for 6 hours, at 120°C under vacuum for 3 hours, and at 150°C under vacuum for 3 hours to obtain hydrolyzed polysilane.

[0110] Step (2): Add 5g of hydrolyzed polysilane ethanol solution to 10.4g of diphenyl phosphate ethanol solution, stir evenly, heat to 70℃ and react for 12h, dry by rotary evaporation to obtain modified silane; add modified silane to epoxy resin, stir evenly to obtain silane adhesive.

[0111] Comparative Example 4: A method for manufacturing an aerogel felt, comprising the following steps:

[0112] S1: Dilute sodium silicate solution to SiO2 concentration of 4.5wt% to obtain silicon source precursor; add 50mL of silicon source precursor to reaction vessel, preheat to 65℃, add 60mL of heptane and 6mL of hexamethyldisilazane in sequence while stirring, stir evenly, add 4mL of 70% nitric acid catalyst, stir and react for 30min, add 2mL of ethanol, stir and react for 1h, let stand, remove aqueous phase, place organic phase slurry in 150℃ environment and dry under normal pressure to obtain silica aerogel powder.

[0113] S2: Substrate fixing: The substrate is constrained on both sides by slits and tautly fixed above the silica aerogel powder;

[0114] S3: Powder feeding: Add silica aerogel powder to the surface of the substrate and smooth the silica aerogel powder on the surface of the aerogel felt.

[0115] S4: Powder fixation: An electrostatic field is used to shuttle and fix silica aerogel powder inside the substrate;

[0116] S5: Powder Cleaning: Clean excess silica aerogel powder from the substrate surface;

[0117] S6: Surface coating: Apply silane adhesive to the upper and lower surfaces of the substrate, heat to 110℃ and cure for 10 hours to obtain aerogel felt.

[0118] The slit dimensions are 1mm high and 8mm wide;

[0119] The straightening method is achieved by moving the substrate 0.5 mm toward the slit side;

[0120] The distance between the substrate and the silica aerogel powder is 1 mm;

[0121] The silane adhesive coating amount is 500 g / m². 2 ;

[0122] The method for preparing the substrate includes the following steps:

[0123] 1 mmol tetraethyl orthosilicate, 4 mmol deionized water, and 4 mmol ethanol were added to a reaction vessel and stirred until homogeneous. 1 mol / L phosphoric acid catalyst was added, and the mixture was heated to 50°C and reacted for 6 h to obtain silica sol. Fiber felt was impregnated in silica sol, 1 mol / L ammonia water and anhydrous ethanol were added, and the mixture was heated to 50-55°C and aged for 24 h to obtain a composite gel. The composite gel was placed in a mixed solution of 6 mL n-hexane and 1 mL trimethylchlorosilane and modified for 24 h to obtain a modified composite gel. The modified composite gel was heated to 80°C and dried for 16 h to obtain the substrate.

[0124] Experiment: Thermal conductivity test: A small heat flow meter was used at 25℃. The sample size was 100mm×100mm×3mm. The test was performed 3 times and the average value was taken.

[0125] High temperature resistance test: flame temperature 800℃, flame length 8cm, distance from sample surface 10mm, duration 30min, and back temperature of 3mm tempered glass recorded with infrared thermal imager.

[0126] Table 1 Performance test data of aerogel mat

[0127]

[0128] Conclusion: The aerogel felt prepared by this invention has excellent thermal insulation and high temperature resistance.

[0129] In Comparative Example 1, the amount of phase transfer agent added was too small, resulting in poor development of the mesoporous structure of the aerogel powder, a large number of mesopores collapsed, low mesoporous ratio, high density, and a significant increase in thermal conductivity.

[0130] In Comparative Example 2, the excessive amount of phase transfer agent led to an increase in the residual amount of silanol. The excessive phase transfer agent diluted the hydrophobic agent hexamethyldisilazane in the organic phase, reduced the rate of interfacial hydrophobication reaction, and caused the gel shrinkage to intensify, the mesopores to collapse, and the thermal conductivity to increase significantly.

[0131] In Comparative Example 3, the ceramic phase carbon layer cannot be formed without boric acid and is easily destroyed by high temperature. The heat is quickly conducted to the glass, resulting in a decrease in high temperature resistance.

[0132] In Comparative Example 4, the drying time under normal pressure was too long, which caused some mesopores to collapse, resulting in a decrease in thermal insulation performance and high temperature resistance.

[0133] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method of making an aerogel blanket, characterized by: The method comprises the following steps: S1: substrate fixation: the two sides of the substrate are constrained by a slit and fixed straight above the silica aerogel powder; S2: powder loading: the silica aerogel powder is added to the surface of the substrate, and the silica aerogel powder on the surface of the aerogel felt is scraped flat; S3: powder fixation: the silica aerogel powder is shuttled and fixed inside the substrate by a physical method; S4: powder cleaning: the excess silica aerogel powder on the surface of the substrate is cleaned; S5: surface coating: the silane adhesive is applied to the upper and lower surfaces of the substrate, heated to 110-115 DEG C for 10-12 h, and the aerogel felt is obtained; The preparation method of the substrate comprises the following steps: tetraethyl orthosilicate, deionized water and ethanol are added into a reaction container, stirred uniformly, a phosphoric acid catalyst is added, heated to 50-55 DEG C for reaction for 6-6.5 h, and a silica sol is obtained; the fiber felt is immersed in the silica sol, ammonia water is added, anhydrous ethanol is added, heated to 50-55 DEG C for aging, and a composite gel is obtained; the composite gel is placed in a mixed solution of n-hexane and trimethylchlorosilane, modified, and a modified composite gel is obtained; the modified composite gel is combusted and dried, and the substrate is obtained; The preparation method of the silica aerogel powder comprises the following steps: The sodium silicate solution is diluted to a SiO2 concentration of 4.5-5 wt%, and a silicon source precursor is obtained; the silicon source precursor is added into a reaction container, preheated to 65-66 DEG C, heptane, hexamethyldisilazane are added in sequence under stirring, stirred uniformly, a nitric acid catalyst is added, stirred and reacted for 30-35 min, a phase transfer agent is added, stirred and reacted for 1-1.5 h, and then the water phase is removed; the organic phase slurry is placed in an environment at 150-155 DEG C, and dried under normal pressure, and the silica aerogel powder is obtained; The preparation method of the silane adhesive comprises the following steps: step (1): 3-aminopropylmethyldiethoxysilane is added into deionized water, gradient heating reaction is carried out, heated to 90-95 DEG C for reaction for 6-6.5 h, heated to 120-125 DEG C for vacuum reaction for 3-3.5 h, heated to 150-155 DEG C for vacuum reaction for 3-3.5 h, and a hydrolysis and polycondensation silane is obtained; Step (2): the ethanol solution of the hydrolysis and polycondensation silane is added into the ethanol solution of the diphenyl phosphate, stirred uniformly, heated to 70-75 DEG C for reaction for 12-16 h, and dried by rotary evaporation, and the modified silane is obtained; Step (3): the modified silane is added into the isopropyl alcohol solution of boric acid, heated to 75-78 DEG C for reaction for 30-35 min, heated to 105-106 DEG C to remove the solvent, and the silane adhesive is obtained.

2. The method of claim 1, wherein: In the preparation process of the silica sol, the molar ratio of tetraethyl orthosilicate: deionized water: ethanol is 1: (4-5): (4-5); in the mixed solution of n-hexane and trimethylchlorosilane, the volume ratio of n-hexane: trimethylchlorosilane is 6: (1-2).

3. The method of claim 1, wherein: In the preparation process of the silica aerogel powder, the volume ratio of the silicon source precursor: heptane: hexamethyldisilazane: nitric acid catalyst: phase transfer agent is 50:60:6:4: (2-4).

4. The method of claim 1, wherein: The mass ratio of 3-aminopropylmethyldiethoxysilane to deionized water is (20.3-21.6):5.4 in the preparation of hydrolytic polycondensation silane.

5. The method of claim 1, wherein: The mass ratio of hydrolytic polycondensation silane to diphenyl phosphate is 5:(10.4-12.6) in the preparation of modified silane.

6. The method of claim 1, wherein: The mass ratio of modified silane to boric acid is 1.5:(1-1.5) in the preparation of silane adhesive.

7. The aerogel felt prepared by the method according to any one of claims 1-6.

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