Preparation method of polyester non-woven heat insulation cloth compounded with silicon dioxide aerogel

Abstract

The invention belongs to the technical field of hydrogel preparation, and particularly relates to a preparation method of polyester non-woven heat insulation cloth compounded with silicon dioxide aerogel, which is characterized by comprising the following specific steps: 1) mixing glue: uniformly mixing a silicon dioxide aerogel solution with an adhesive, adding water for dilution, fully stirring and standing to obtain mixed glue; a mixed glue solution is obtained; 2) coating: uniformly coating the surface of the polyester non-woven heat insulation cloth with the mixed glue solution to fully saturate and adsorb the mixed glue solution; 3) drying: placing the polyester non-woven heat insulation cloth in a drying oven, completely volatilizing the solvent, and fully curing and molding the aerogel; and 4) cooling and storing: naturally cooling the dried composite silicon dioxide aerogel polyester non-woven heat-insulating cloth at room temperature, and performing vacuum packaging. The method has the beneficial effects that the coal gasification slag is used as a raw material, solid resources are utilized in a waste source manner, the heat insulation performance is remarkably improved, and key mechanical parameters such as breaking strength and compressive strength are improved in a breakthrough manner.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogel preparation, and in particular relates to a method for preparing a polyester non-woven thermal insulation cloth composited with silica aerogel. Background Art

[0002] Currently, global attention is being focused on the development of new energy sources, improving the efficiency of existing energy resources, and promoting energy-saving measures. Given my country's relatively scarce energy resources, the scientific and rational use of energy and a commitment to energy conservation are of immeasurable value in promoting sustainable social development. Against this backdrop, utilizing cutting-edge technologies and innovative processes to develop environmentally friendly and efficient thermal insulation materials is undoubtedly one of the most effective and cost-effective ways to achieve energy conservation goals.

[0003] Aerogel is a nanoscale porous solid material formed through a sol-gel process. Its internal pores are filled with gas, making it one of the world's lowest-density solids. Silica aerogel is the result of an exploration of the application of silica based on aerogel technology. Compared to other aerogel materials, silica aerogel is a lightweight, nanoporous, amorphous solid material with excellent fire resistance and thermal insulation properties, featuring low density, low thermal conductivity, high porosity, and a high specific surface area. Silica aerogel has a wide range of applications in the field of thermal insulation. For example, it can be used in building wall insulation, pipe insulation, thermal insulation coatings, energy-saving glass, pipeline corrosion protection, and adsorption catalysis.

[0004] Polyester nonwovens are fabrics that do not require spinning or weaving. Instead, they are made by aligning or randomly arranging short textile fibers or filaments to form a web structure, which is then reinforced mechanically, thermally, or chemically. As a high-performance industrial textile material, polyester nonwovens have long been widely used in various industries of the national economy. However, there are few reports on the use of silica aerogels to improve the performance of polyester nonwovens. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a polyester non-woven thermal insulation fabric composited with silica aerogel, overcoming the shortcomings of the prior art. The silica aerogel is prepared by using the siliceous components in industrial solid waste coal gasification slag, and the silica aerogel is used in the processing of polyester non-woven fabric by a coating method to produce a non-woven thermal insulation fabric with good thermal insulation and flame retardant properties, thereby achieving the effect of solid waste resource utilization.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A preparation method for a polyester nonwoven thermal insulation fabric composited with silica aerogel includes mixing, coating, drying, and cooling for storage. The specific steps are as follows: 1) mixing, uniformly mixing a silica aerogel solution and an adhesive in a weight ratio of 3:1-3:2, adding water to dilute the mixture 4-6 times, stirring thoroughly, and standing at room temperature of 25°C for 10-12 hours to obtain a mixed solution; 2) coating, uniformly coating the mixed solution on the surface of the polyester nonwoven thermal insulation fabric through an applicator. The physicochemical parameters of the polyester nonwoven thermal insulation fabric are: thickness 0.5-1 mm, surface density 50-200 g / m 2 , breaking strength of 30-100N, transverse elongation of 20-50%, thermal conductivity of 0.03-0.05W / (m·K), burning time of 10-20s, compressive strength of 50-100kPa, so that the polyester nonwoven thermal insulation fabric is fully saturated with the mixed glue solution; 3) drying, the coated polyester nonwoven thermal insulation fabric is placed in a blast oven and dried at 80-100℃ for 10-12 hours to completely evaporate the solvent and fully solidify the aerogel into a shape with a curing degree of more than 95%; 4) cooling The polyester nonwoven thermal insulation fabric after drying in step 3) is naturally cooled to room temperature to obtain a composite silica aerogel polyester nonwoven thermal insulation fabric product, which is placed in a moisture-proof bag, vacuumed and sealed, and stored in a cool and dry environment. The physicochemical parameters of the product are: thickness 0.5-1 mm, breaking strength 50-200 N, lateral elongation 30-60%, thermal conductivity 0.0214-0.0264 W / (m·K), burning time 25-30 s, and compressive strength 200-500 kPa.

[0008] The adhesive is any one of polyurea, polyurethane and phenolic resin.

[0009] The preparation steps of the silica aerogel solution are as follows:

[0010] 1) Pretreatment: Dry the coal gasification slag, grind it to a particle size of 20 μm, pass it through a 200-mesh sieve, and retain the undersize powder. The physicochemical parameters of the undersize powder are: ash 60-80%, organic carbon 5-20%, and moisture 10-30%. The main chemical components of the ash are, by weight, SiO2 35-60%, Al2O3 15-30%, CaO 5-20%, and Fe2O3 10-15%;

[0011] 2) Dissolution reaction: Mix the undersize powder with a sodium hydroxide solution having a mass concentration of 20-30% at a solid-liquid ratio of 1:5-1:6, stir evenly, pour into a hydrothermal reactor, and heat at 160-200° C. for 6-8 hours to complete the dissolution reaction to obtain a sodium silicate mixed solution;

[0012] 3) filtering the sodium silicate mixed solution through a vacuum filtration device, wherein the filtrate is the sodium silicate solution and the filter residue is discarded;

[0013] 4) Ion exchange: pass the sodium silicate solution through an ion exchange column filled with cation exchange resin to exchange the Na + With H in the resin + After sufficient exchange, a silicic acid solution is obtained;

[0014] 5) hydrolysis and polycondensation reaction: adding 25-30% ammonia water to the silicic acid solution, adjusting the pH to 5-6, then heating the solution to 80-85° C. and aging it at a constant temperature for 10-12 hours to allow the silicic acid solution to undergo hydrolysis and polycondensation reactions to form a hydrogel with a three-dimensional network structure;

[0015] 6) Ethanol replacement: immerse the hydrogel in an equal volume of anhydrous ethanol solution at 20-25°C for 20-24 hours to replace the water in the hydrogel with ethanol. At the same time, ethanol occupies the hydrogel network pores, forming an aged hydrogel with a relatively loose structure.

[0016] 7) Obtaining aerogel: adding the aged hydrogel to a mixed solution of an alkylating agent and anhydrous ethanol in a volume ratio of 1:2-1:3, and soaking the solution in a water bath at 50-60°C for 10-12 hours to obtain a silica aerogel solution. The physicochemical parameters of the silica aerogel solution are: density 0.05-0.2 g / m 3 , specific surface area 500-1000m 2 / g, porosity 85-95%.

[0017] The cation exchange resin is a sulfonic acid type strongly acidic cation exchange resin, with a model of 001×7, an exchange capacity of ≥4.5 mmol / g, and a flow rate of 1-2 mL / min during ion exchange.

[0018] The alkylating agent is a brominated alkane or a chloroalkane, wherein the brominated alkane is any one of ethyl bromide, n-butyl bromide and dodecane bromide; and the chloroalkane is any one of dichloromethane, chloroform and 1,2-dichloroethane.

[0019] The alkylating agent is ethyl chloride.

[0020] The polyurea adhesive is model AG-16-Flex.

[0021] The cool and dry environment refers to an environment with a temperature of 5-25°C, a humidity of 50-70% and good ventilation.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) Significantly improve thermal insulation performance and thermal conductivity. Compounding it with polyester nonwoven fabric can significantly enhance the thermal insulation effect of the insulation cloth and effectively block heat transfer. Multi-mechanism thermal insulation: The thermal insulation mechanisms of silica aerogel include zero convection effect, infinite heat shield effect, and long-path effect. These mechanisms work together to make the insulation cloth far superior to traditional materials in terms of thermal insulation performance.

[0024] 2) Enhance the mechanical properties of the material, achieving a breakthrough in the key mechanical parameters of breaking strength and compressive strength. Polyester nonwoven fabric as the base material provides good mechanical strength and durability, allowing the insulation cloth to withstand certain stretching, bending and wear, extending its service life. Good flexibility: By increasing the elongation, the insulation cloth can adapt to surfaces of various complex shapes and structures, improving the convenience of installation and use;

[0025] 3) Energy saving and environmental protection, energy saving and emission reduction. Due to the improvement of thermal insulation performance, the application of polyester nonwoven composite silica aerogel insulation cloth in the fields of construction, transportation and industry can significantly reduce energy consumption and greenhouse gas emissions, which is in line with the current environmental protection concept of energy conservation and emission reduction. The material is environmentally friendly. Silica aerogel is a non-toxic, harmless and environmentally friendly material that will not harm the environment and human health.

[0026] 4) Broad application prospects: Construction: Used in roofs, walls, and floor structures, it can significantly improve the thermal insulation performance of buildings and reduce energy consumption. Transportation: Used in the thermal insulation systems of cars, trains, and airplanes, it can improve passenger comfort and reduce energy consumption. Industrial: Used in the thermal insulation of pipelines, storage tanks, and equipment, it can reduce heat loss and improve energy efficiency.

[0027] 5) Innovative composite technology organically combines silica aerogel with polyester nonwoven fabric, achieving significant improvements in thermal conductivity, mechanical properties and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is a comparison chart of thermal conductivity of Example 1 of the present invention and the comparative example at different test times;

[0029] Figure 2 This is a comparison chart of the burning time of Example 1 of the present invention and the comparative example at different detection times;

[0030] Figure 3 This is a comparison chart of the breaking strength of Example 1 of the present invention and the comparative example at different test times;

[0031] Figure 4 1 is a comparison chart of the compressive strength of Example 1 of the present invention and the comparative example at different test times;

[0032] Figure 5 3 is a comparison chart of the elongation of Example 1 of the present invention and the comparative example at different detection times. DETAILED DESCRIPTION

[0033] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0034] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation methods of the present invention. For ordinary technicians in this field, other specific embodiments can be obtained based on these specific embodiments without paying any creative work.

[0035] The components of the embodiments of the present invention generally described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention.

[0036] In the following examples, the silica aerogel solution was prepared as follows: 1) pretreatment: drying the coal gasification slag, grinding it to a particle size of 20 μm, passing it through a 200-mesh sieve, and retaining the undersize powder. The physicochemical parameters of the undersize powder were: organic carbon 5-20%, moisture 10-30%, and ash 60-80%. The main chemical components of the ash were, by weight, SiO2 35-60%, Al2O3 15-30%, CaO 5-20%, and Fe2O3 10-15%; 2) dissolution reaction, the powder under the sieve is mixed with a sodium hydroxide solution with a mass concentration of 20-30% at a solid-liquid ratio of 1:5-1:6, stirred evenly, poured into a hydrothermal reactor, and heated at 160-200 ° C for 6-8 hours to complete the dissolution reaction to obtain a sodium silicate mixed solution; 3) the sodium silicate mixed solution is filtered through a vacuum filtration device, the filtrate is the sodium silicate solution, and the filter residue is discarded; 4) ion exchange, the sodium silicate solution is passed through an ion exchange column equipped with a cation exchange resin to make the Na in the sodium silicate solution + With H in the resin +Fully exchange to obtain a silicic acid solution; 5) hydrolysis and polycondensation reaction, adding ammonia water with a mass concentration of 25-30% to the silicic acid solution, adjusting the pH value to 5-6, then heating the solution to 80-85°C, and aging it at a constant temperature for 10-12 hours to allow the silicic acid solution to undergo hydrolysis and polycondensation reactions to form a hydrogel with a three-dimensional network structure; 6) ethanol replacement, immersing the hydrogel in an equal volume of anhydrous ethanol solution, soaking it at 20-25°C for 20-24 hours, so that the water in the hydrogel is replaced by ethanol, and at the same time, ethanol occupies the hydrogel network pores to form an aged hydrogel with a relatively loose structure; 7) obtaining an aerogel, adding the aged hydrogel to a mixed solution prepared by an alkylating agent and anhydrous ethanol in a volume ratio of 1:2-1:3, and soaking it in a water bath at 50-60°C for 10-12 hours to finally obtain a silica aerogel solution. The alkylating agent is a brominated alkane or a chlorinated alkane, wherein the brominated alkane is any one of ethyl bromide, n-butyl bromide and dodecane bromide; and the chlorinated alkane is any one of dichloromethane, chloroform and 1,2-dichloroethane. The preferred alkylating agent is ethyl chloride.

[0037] The cation exchange resin is a sulfonic acid-type strongly acidic cation exchange resin, model 001×7, with an exchange capacity ≥4.5 mmol / g and a flow rate of 1-2 mL / min. A cool, dry environment is defined as one with a temperature of 5-25°C, a humidity of 50-70%, and good ventilation.

[0038] Example 1

[0039] A method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel includes mixing, coating, drying, and cooling and storage. The specific steps are as follows:

[0040] 1) Mixing: uniformly mix the silica aerogel solution and the adhesive (polyurea) in a weight ratio of 3:2, add water to dilute 4 times, stir thoroughly, and let stand at room temperature of 25°C for 10 hours to obtain a mixed adhesive solution; the model of the polyurea adhesive used is AG-16-Flex;

[0041] 2) coating, coating the mixed glue solution evenly on the surface of the polyester nonwoven thermal insulation fabric through a coater, so that the polyester nonwoven thermal insulation fabric is fully saturated with the mixed glue solution;

[0042] 3) Drying: Place the coated polyester nonwoven insulation in a blast oven and dry it at 80-100° C. for 10 hours to completely evaporate the solvent and fully solidify the aerogel to a degree of curing of more than 95%;

[0043] 4) Cooling and storing, the polyester nonwoven thermal insulation fabric after drying in step 3) is naturally cooled to room temperature to obtain a composite silica aerogel polyester nonwoven thermal insulation fabric product, which is placed in a moisture-proof bag, evacuated and sealed, and stored in a cool and dry environment. The physicochemical parameters of the product are: thickness 0.5 mm, breaking strength 160 N, elongation 40%, thermal conductivity 0.0214 W / (m·K), burning time 26 s, and compressive strength 300 kPa.

[0044] Example 2

[0045] A method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel includes mixing, coating, drying, and cooling and storage. The specific steps are as follows:

[0046] 1) Mixing the silica aerogel solution and the adhesive (polyurethane) in a weight ratio of 3:2, adding water to dilute 5 times, stirring thoroughly, and standing at room temperature of 25° C. for 12 hours to obtain a mixed adhesive solution; the model of the polyurethane adhesive is Sikaflex-221;

[0047] 2) coating, coating the mixed glue solution evenly on the surface of the polyester nonwoven thermal insulation fabric through a coater, so that the polyester nonwoven thermal insulation fabric is fully saturated with the mixed glue solution;

[0048] 3) Drying: Place the coated polyester nonwoven insulation in a blast oven and dry at 90° C. for 12 hours to completely evaporate the solvent and fully solidify the aerogel to a degree of curing exceeding 95%;

[0049] 4) Cooling and storing, the polyester nonwoven thermal insulation fabric after drying in step 3) is naturally cooled to room temperature to obtain a composite silica aerogel polyester nonwoven thermal insulation fabric product, which is placed in a moisture-proof bag, evacuated and sealed, and stored in a cool and dry environment. The physicochemical parameters of the product are: thickness 0.5 mm, breaking strength 170 N, elongation 50%, thermal conductivity 0.0264 W / (m·K), burning time 28 s, and compressive strength 400 kPa.

[0050] Example 3

[0051] A method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel includes mixing, coating, drying, and cooling and storage. The specific steps are as follows:

[0052] 1) Mixing the silica aerogel solution and the binder (phenolic resin) in a weight ratio of 3:2, adding water to dilute the mixture 6 times, stirring the mixture thoroughly, and standing the mixture at room temperature of 25° C. for 11 hours to obtain a mixed solution; the model of the phenolic resin binder is Plenco 1179;

[0053] 2) coating, coating the mixed glue solution evenly on the surface of the polyester nonwoven thermal insulation fabric through a coater, so that the polyester nonwoven thermal insulation fabric is fully saturated with the mixed glue solution;

[0054] 3) Drying: Place the coated polyester nonwoven insulation in a blast oven and dry it at 100° C. for 12 hours to completely evaporate the solvent and fully solidify the aerogel to a degree of curing of more than 95%;

[0055] 4) Cooling and storing, the polyester nonwoven thermal insulation fabric after drying in step 3) is naturally cooled to room temperature to obtain a composite silica aerogel polyester nonwoven thermal insulation fabric product, which is placed in a moisture-proof bag, evacuated and sealed, and stored in a cool and dry environment. The physicochemical parameters of the product are: thickness 0.5 mm, breaking strength 200 N, elongation 60%, thermal conductivity 0.0216 W / (m·K), burning time 30 s, and compressive strength 500 kPa.

[0056] Comparative Example

[0057] The blank sample of polyester nonwoven fabric is based on the PET series (trade name PET-200) of the national standard GB / T 17639-2008, and its physicochemical parameters are surface density 150g / m 2 , breaking strength 70N, elongation 30%, thermal conductivity 0.0355W / (m·K), burning time 11s, compressive strength 70kPa, used as unmodified reference material for performance comparison test.

[0058] The product performance of the above Examples 1-3 and the comparative example was tested; four groups of polyester non-woven fabric substrates (specifications 300 mm × 300 mm × 0.5 mm) were selected by random sampling, and a blank control group and a composite silica aerogel modified sample experimental group were set up. Each group of samples was tested in parallel 6 times, and the arithmetic mean was used as the basis for characterizing the thermal insulation, flame retardancy and mechanical properties of the material.

[0059] Through the steady-state method combined with the C-THERM TCi thermal conductivity analyzer, the test results at 500°C showed that the thermal conductivity of the blank polyester non-woven fabric was 0.0355W / (m·K), while the thermal conductivity of the composite silica aerogel modified sample was significantly reduced to 0.0214W / (m·K), verifying the strengthening effect of silica aerogel on thermal insulation performance; according to the GB / T 5455-2014 standard, the vertical combustion test was carried out, and the burning time of the composite sample was extended from 11 seconds of the blank sample to 30 seconds, indicating that silica aerogel can effectively inhibit the combustion behavior of the material; the test using the electronic fabric strength tester (YG020A model) showed that the breaking strength of the three groups of aerogel modified samples reached 160N, 170N and 200N, which were all improved compared with the blank sample (70N), confirming the mechanical strength gain effect; based on the GB / T In the 13761.1 standard compressive strength test, the compressive strength of the modified samples was 300kPa, 400kPa and 500kPa, which was a significant increase compared with the blank sample (70kPa), highlighting the enhancement effect of silica aerogel on the compressive bearing capacity; according to the GB / T 24218.102-2022 standard flexibility test results, the elongation of the modified samples reached 40%, 50% and 60%, which was 10-30 percentage points higher than the blank sample (30%), proving that silica aerogel modification can significantly improve the plastic deformation ability of non-woven fabrics.

[0060] The thermal conductivity, burning time, breaking strength, compressive strength and elongation data of the above Examples 1-3 and the polyester nonwoven fabric blank sample are compared in Table 1.

[0061] Table 1

[0062]

[0063] The data in Table 1 demonstrates that the introduction of silica aerogel enables the synergistic optimization of thermal insulation, flame retardancy, and mechanical properties in polyester nonwovens. By organically combining silica aerogel with polyester nonwovens through innovative composite technology, a breakthrough improvement in the material's overall performance is achieved, addressing the high cost of traditional supercritical drying.

[0064] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel, characterized in that: Including mixing glue, coating, drying and cooling storage, the specific steps are as follows: 1) Mixing the silica aerogel solution and the adhesive in a weight ratio of 3:1-3:2, adding water to dilute 4-6 times, stirring thoroughly, and standing at room temperature of 25° C. for 10-12 hours to obtain a mixed glue solution; 2) Coating: evenly coat the mixed glue solution on the surface of polyester nonwoven insulation fabric through a coater. The physical and chemical parameters of polyester nonwoven insulation fabric are: thickness 0.5-1mm, surface density 50-200g / m 2 , breaking strength is 30-100N, transverse elongation is 20-50%, thermal conductivity is 0.03-0.05W / (m·K), burning time is 10-20s, compressive strength is 50-100kPa, so that the polyester nonwoven insulation fabric is fully saturated with the mixed glue solution; 3) Drying: Place the coated polyester nonwoven insulation in a blast oven and dry it at 80-100° C. for 10-12 hours to completely evaporate the solvent and fully solidify the aerogel to a degree of curing of more than 95%; 4) Cooling and storing, the polyester nonwoven thermal insulation fabric after drying in step 3) is naturally cooled to room temperature to obtain a composite silica aerogel polyester nonwoven thermal insulation fabric product, which is placed in a moisture-proof bag, evacuated and sealed, and stored in a cool and dry environment. The physicochemical parameters of the product are: thickness 0.5-1 mm, breaking strength 50-200 N, lateral elongation 30-60%, thermal conductivity 0.0214-0.0264 W / (m·K), burning time 25-30 s, and compressive strength 200-500 kPa.

2. The method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel according to claim 1, characterized in that: The adhesive is any one of polyurea, polyurethane and phenolic resin.

3. The method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel according to claim 1, characterized in that: The preparation steps of the silica aerogel solution are as follows: 1) Pretreatment: The coal gasification slag is dried, ground to a particle size of 20 μm, and passed through a 200-mesh sieve. The undersize powder is retained. The physicochemical parameters of the undersize powder are: ash 60-80%, organic carbon 5-20%, and moisture 10-30%. The main chemical components of the ash are, by weight, SiO2 35-50%, Al2O3 15-30%, CaO 5-20%, and Fe2O3 10-15%; 2) Dissolution reaction: Mix the undersize powder with a sodium hydroxide solution having a mass concentration of 20-30% at a solid-liquid ratio of 1:5-1:6, stir evenly, pour into a hydrothermal reactor, and heat at 160-200° C. for 6-8 hours to complete the dissolution reaction to obtain a sodium silicate mixed solution; 3) filtering the sodium silicate mixed solution through a vacuum filtration device, wherein the filtrate is the sodium silicate solution and the filter residue is discarded; 4) Ion exchange: pass the sodium silicate solution through an ion exchange column filled with cation exchange resin to exchange the Na + With H in the resin + After sufficient exchange, a silicic acid solution is obtained; 5) hydrolysis and polycondensation reaction: adding 25-30% ammonia water to the silicic acid solution, adjusting the pH to 5-6, then heating the solution to 80-85° C. and aging it at a constant temperature for 10-12 hours to allow the silicic acid solution to undergo hydrolysis and polycondensation reactions to form a hydrogel with a three-dimensional network structure; 6) Ethanol replacement: immerse the hydrogel in an equal volume of anhydrous ethanol solution at 20-25°C for 20-24 hours to replace the water in the hydrogel with ethanol. At the same time, ethanol occupies the hydrogel network pores, forming a loose aged hydrogel; 7) Obtaining aerogel: adding the aged hydrogel to a mixed solution of an alkylating agent and anhydrous ethanol in a volume ratio of 1:2-1:3, and soaking the solution in a water bath at 50-60°C for 10-12 hours to obtain a silica aerogel solution. The physicochemical parameters of the silica aerogel solution are: density 0.05-0.2 g / m 3 , specific surface area 500-1000m 2 / g, porosity 85-95%.

4. The method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel according to claim 3, characterized in that: The cation exchange resin is a sulfonic acid type strongly acidic cation exchange resin, with a model of 001×7, an exchange capacity of ≥4.5 mmol / g, and a flow rate of 1-2 mL / min during ion exchange.

5. The method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel according to claim 3, characterized in that: The alkylating agent is a brominated alkane or a chloroalkane, wherein the brominated alkane is any one of ethyl bromide, n-butyl bromide and dodecane bromide; and the chloroalkane is any one of dichloromethane, chloroform and 1,2-dichloroethane.

6. The method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel according to claim 3, characterized in that: The alkylating agent is ethyl chloride.

7. The method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel according to claim 2, characterized in that: The polyurea adhesive is model AG-16-Flex.

8. The method for preparing a polyester nonwoven thermal insulation fabric composited with silica aerogel according to claim 1, characterized in that: The cool and dry environment refers to an environment with a temperature of 5-25°C, a humidity of 50-70% and good ventilation.

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