Heat insulating aerogel fiber and its manufacturing method

Abstract

To provide a thermal-insulation and temperature-keeping aerogel fiber that can avoid influence to fiber performance caused by breaking of aerogel in the fiber, and can improve moisture absorbability and dyeability of aerogel fiber, and a method for manufacturing the fiber.SOLUTION: An aerogel fiber is a two-layered structure in which an inner layer includes SiO2 aerogel and cellulose aerogel, and an outer layer is a protein membrane. Plant powder and silicon source auxiliary additive are added to a fiber raw material and mixed, the mixture is allowed to pass through spinning holes to manufacture an initial fiber, the plant powder and the silicon source auxiliary additive are distributed into the initial fiber, and furthermore, immersed into dispersion liquid, cellulose aerogel and SiO2 aerogel are uniformly generated inside the initial fiber after passing through a step such as extremely low temperature treatment to obtain an aerogel composite fiber, the aerogel composite fiber is immersed into fruit acid auxiliary additive containing protein to allow protein and fruit acid to cause cross-linking reaction, a single layer of a protein membrane is formed on a surface of the aerogel composite fiber, and a two-layered structure in which the inner layer is an aerogel composite fiber and the outer layer is a protein membrane is obtained.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention belongs to the field of fiber technology, and specifically relates to a heat-insulating and heat-retaining aerogel fiber and a method for producing the same. [Background technology]

[0002] Aerogel is a porous material derived from gel. It has characteristics such as a high specific surface area, high porosity, low density, and low thermal conductivity, and has great prospects for application in fields such as biology, medicine, and architecture. With intensive research, aerogel is gradually being applied to the field of fiber spinning, and adding aerogel to fibers and fabrics can give the fibers a lightweight thermal insulation effect. In aerogel research, SiO2 aerogel is the mainstream research direction in the spinning field. SiO2 aerogel has a wide range of applications, but its disadvantage is that it is brittle and prone to generating debris and powder during the actual production process.

[0003] SiO2 aerogel fabrics have poor spinnability and plasticity. Take nonwoven sandwich materials as an example. Nonwoven sandwich materials are three-layer filled fabrics with a nonwoven substrate as the sandwich layer and an aerogel as the core layer. The nonwoven substrate is typically limited to polyester or polypropylene. While nonwoven sandwich materials offer thermal insulation, they are rarely used for fabric weaving and cannot be dyed due to the substrate. Furthermore, nonwoven sandwich materials have low surface moisture and are prone to static electricity, which can cause damage to the human body, for example, irritating the skin and reducing its moisture content, leading to symptoms such as dry skin, flaking, and itching. Fabrics made from nonwoven sandwich materials tend to have high basis weights and are heavy, reaching thicknesses of over 0.3 cm for a single layer, making them less comfortable to wear and limiting their development in the textile industry.

[0004] To expand the applications of SiO2 aerogel in the textile industry, researchers have made a breakthrough in aerogel fiber. Many commercially available fibers containing SiO2 aerogel are made by directly blending SiO2 aerogel powder with polymer fragments or spinning dope. For example, in patent number "CN202211310230.9" titled "Graphene Aerogel Fiber and Manufacturing Method Thereof," polyester fragments are pulverized, and then the powder is mixed with graphene material, aerogel glass bead material, and modifiers. The resulting composite masterbatch is then extruded and granulated, and melt-spun. However, SiO2 aerogel is highly brittle and its porous structure is easily broken. During the spinning process, the voids in the SiO2 aerogel collapse, resulting in uneven distribution of the porous structure in the fiber and affecting fiber performance. Summary of the Invention [Problem to be solved by the invention]

[0005] To solve the problems in the prior art, the present invention provides a heat-insulating and heat-retaining aerogel fiber and a manufacturing method thereof, which avoids the impact of aerogel fragmentation in the fiber on fiber performance and improves the moisture absorption and dyeability of the aerogel fiber. [Means for solving the problem]

[0006] In order to solve the above technical problems, the present invention employs the following technical means. The first object of the present invention is to provide a heat-insulating aerogel fiber having a two-layer structure in which the inner layer is an aerogel composite fiber containing SiO2 aerogel and cellulose aerogel, and the outer layer is a protein membrane. A second object of the present invention is to provide a method for producing a thermal insulating aerogel fiber, which comprises the following steps:

[0007] S1: Add plant powder and silicon source additive to the fiber raw material and stir for 30-40 minutes to obtain mixed fiber raw material; S2: The mixed fiber raw material is extruded through the spinning hole and then stretched to obtain the initial fiber;

[0008] S3: The initial fiber is immersed in a dispersion, left to stand, cryogenically treated, and dissolved to obtain aerogel composite fiber, which further contains protein. organic acid The material is immersed in an auxiliary agent to react, then washed with water, pre-dried, and then re-dried to produce a heat-insulating aerogel fiber with a two-layer structure.

[0009] Preferably, the plant powder in S1 is flax, conifer, sugarcane, cotton, seaweed, to It is a powder of one or more types of corn, and the particle size of the powder is 300nm-2μm. Preferably, the silicon source auxiliary in S1 is one or more of sodium silicate, silicon tetrachloride, methyl orthosilicate, and ethyl orthosilicate.

[0010] Preferably, the fibers of the fiber raw material in S1 are polyester, regenerated cellulose fiber, polyurethane, Na It is one or more of iron and acrylic.

[0011] Preferably, the stirring speed is 500-800 r / min. Preferably, the amount of plant powder added in S1 is 0.3-10 wt % of the active ingredients of the fiber raw material.

[0012] Preferably, the amount of silicon source auxiliary added in S1 is 1-5 wt% of the effective components of the fiber raw material. The effective component of the cellulose fiber raw material is the type A cellulose in the cellulose fiber spinning dope.

[0013] Preferably, the solute of the dispersion liquid in S3 is one or more of sodium bicarbonate, ammonia monohydrate, dimethylamine, triethylamine, aniline, and pyridine, and the solvent is water.

[0014] Preferably, the concentration of the dispersion in S3 is 0.5-2 wt%. Preferably, the standing time in S3 is 3 to 5 minutes. Preferably, the temperature of the cryogenic treatment in S3 is −196° C. and the time is 1-10 s.

[0015] Preferably, an organic solvent is used for elution in S3, and the organic solvent is one or more of methanol, ethanol, isopropanol, and acetone.

[0016] Preferably, the S3 contains a protein organic acid The auxiliary agent is protein, organic acid and water, wherein the protein is one or more of soybean-derived protein, wheat protein, pea protein, corn protein, and keratin protein; organic acid is citric acid, malic acid, Ta The preferred citric acid is one or more of the following: Furthermore, a compound containing the protein organic acid In the auxiliary, protein accounts for 10-15 wt%. organic acid accounts for 2-4 wt%, and the rest is water.

[0017] Preferably, the aerogel composite fiber in S3 is a protein-containing organic acid The reaction is carried out by immersing in the auxiliary agent, the reaction time is 4-5 hours, and the reaction temperature is 30-35°C.

[0018] Preferably, the temperature of the pre-drying in S3 is 60°C to 90°C, and the time is 50 to 60 minutes. Preferably, the drying temperature in S3 is 120-150°C and the drying time is 90-120 minutes. [Effects of the Invention]

[0019] By adopting the above technical solution, the technical effects achieved by the present invention are as follows:

[0020] 1. The heat-insulating and heat-retaining aerogel fiber produced by the present invention has a fineness of 0.5-9 dtex and a density of 0.7-1.0 g / cm 3The bulkiness is >5cm, and the thickness of a single layer after fabrication is less than 0.02cm, making it lighter and more comfortable to wear.

[0021] 2. The thermal conductivity of the heat-insulating and heat-retaining aerogel fiber produced by the present invention is 0.008-0.02 w / m·K (measured in accordance with GB / T 35762-2017). This is comparable to the thermal conductivity of ordinary acrylic fiber, which is 0.032 w / m·K, the thermal conductivity of ordinary polyester, which is 0.07 w / m·K, and the thermal conductivity of hollow polyester, which is 0.04 w / m·K. Therefore, the heat-insulating and heat-retaining performance is better than that of ordinary fibers. The fiber also has good moisture absorption, with a moisture content of more than 2% and excellent quick-drying performance, with an evaporation rate of more than 0.2 g / h (measured in accordance with GB / T 21655.1-2008). This lightweight fiber not only retains heat but also absorbs moisture and dries quickly.

[0022] 3. The heat-insulating and heat-retaining aerogel fiber produced by the present invention has far-infrared temperature-raising properties, including a far-infrared emissivity of more than 0.88 and a temperature rise of more than 3°C when exposed to far-infrared rays (measured according to GB / T 30127-2013). It also has good dyeing properties, with dyeing uniformity of grade 4 or above.

[0023] 4. In the present invention, plant powder and silicon source additive are added to and blended with fiber raw materials, and then the initial fibers are produced through spinning holes. The plant powder and silicon source additive are distributed inside the initial fibers, which are then immersed in a dispersion liquid and subjected to cryogenic treatment, etc., to uniformly generate cellulose aerogel and SiO2 aerogel inside the initial fibers, thereby obtaining aerogel composite fibers. The cellulose aerogel and SiO2 aerogel are directly blended with the fiber raw materials and extruded, avoiding certain destruction of the aerogel structure during the process of drawing into fibers, and avoiding the adverse effect of the broken aerogel structure on the fiber performance.

[0024] 5. Aerogel composite fiber containing protein organic acid Immerse in the auxiliary agent and organic acidA cross-linking reaction occurs, forming a layer of protein film on the surface of the aerogel composite fiber, resulting in a two-layer structure with an inner layer of aerogel composite fiber and an outer layer of protein film. The formation of the protein film makes the fiber more skin-friendly and at the same time improves the moisture absorption and dyeing effect of the fiber.

[0025] 6. In S3, a pre-drying and then drying process is adopted to further solidify the protein film on the surface of the aerogel composite fiber, avoiding the protein film shrinking unevenly and rapidly at high temperatures, resulting in bubbles, small patterns, etc., which would affect the appearance of the fiber. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will now be further described with reference to specific examples. Example 1 S1, flax powder, and ethyl orthosilicate were added to the polyester slices and stirred for 35 minutes, and the stirring speed was 600 r / min, to obtain a mixed fiber material. S2. Melt spinning is used, in which the mixed fiber raw material is melted and then extruded through the spinning hole and drawn to obtain the initial fiber;

[0027] S3: The initial fiber is immersed in a dispersion, left to stand, cryogenically treated, and dissolved to obtain aerogel composite fiber, which further contains protein. organic acid The material is immersed in an auxiliary agent to react, then washed with water, pre-dried, and then re-dried to produce a heat-insulating aerogel fiber with a two-layer structure.

[0028] The particle size of the flax powder in S1 is 1 μm. The amount of flax powder added in S1 is 5 wt% of the polyester slice. The amount of ethyl orthosilicate added in S1 was 3 wt % of the polyester slices.

[0029] The process parameters for melt spinning in S2 are as follows: temperature in zone 1 is 300°C, temperature in zone 2 is 315°C, temperature in zone 3 is 310°C, and temperature in zone 4 is 305°C.

[0030] The solute of the dispersion in S3 is triethylamine, the solvent is water, and the concentration of the dispersion is 1.5 wt %. The standing time in S3 is 4 minutes, the temperature of the cryogenic treatment is −196° C., and the time is 7 seconds.

[0031] An organic solvent is used for elution in S3, and the organic solvent is isopropanol. Proteins in S3 organic acid In the auxiliary, the soybean-derived protein accounts for 12 wt%, the citric acid accounts for 3 wt%, and the remainder is water.

[0032] In the step S3, the aerogel composite fiber is mixed with a protein-containing organic acid The reaction was carried out by immersing in the auxiliary agent, the reaction time was 4.5 hours, and the reaction temperature was 35°C. The preliminary drying temperature in S3 is 70° C. and the time is 55 minutes. In S3, the drying temperature is 140° C. and the drying time is 100 minutes.

[0033] The heat-insulating and heat-retaining aerogel fiber produced in Example 1 has a fineness of 1.5 dtex and a density of 0.76 g / cm 3 The breaking strength was 4.4 cN / dtex, the bulkiness was 5.8 cm, the thermal conductivity coefficient was 0.012 w / m K, the moisture content was 3%, the evaporation rate was 0.25 g / h, the far-infrared emissivity was 0.91, the far-infrared irradiation temperature was 3.6°C, and the dyeing uniformity was grade 4.

[0034] Example 2 S1, cotton powder, and sodium silicate were added to the polyester slices and stirred at a stirring speed of 800 r / min for 30 min to obtain a blended fiber material. S2. Melt spinning is used, in which the mixed fiber raw material is melted and then extruded through the spinning hole and drawn to obtain the initial fiber;

[0035] S3: The initial fiber is immersed in a dispersion, left to stand, cryogenically treated, and dissolved to obtain aerogel composite fiber, which further contains protein. organic acid The material is immersed in an auxiliary agent to react, then washed with water, pre-dried, and then re-dried to produce a heat-insulating aerogel fiber with a two-layer structure.

[0036] The particle size of the flax powder in S1 is 2 μm. The amount of flax powder added in S1 is 0.3 wt% of the polyester slice. The amount of ethyl orthosilicate added in S1 was 1 wt % of the polyester slices.

[0037] The process parameters for melt spinning in S2 are as follows: temperature in zone 1 is 300°C, temperature in zone 2 is 315°C, temperature in zone 3 is 310°C, and temperature in zone 4 is 305°C.

[0038] The solute of the dispersion in S3 is triethylamine, the solvent is water, and the concentration of the dispersion is 0.5 wt %. The standing time in S3 is 3 minutes, the temperature of the cryogenic treatment is −196° C., and the time is 1 second.

[0039] An organic solvent is used for elution in S3, and the organic solvent is ethanol. Proteins in S3 organic acid In the adjuvant, corn protein accounts for 10 wt%, tannic acid accounts for 2 wt%, and the remainder is water.

[0040] In the step S3, the aerogel composite fiber is mixed with a protein-containing organic acid The reaction time is 4 hours and the reaction temperature is 30°C. The preliminary drying temperature in S3 is 60° C. and the time is 50 minutes. The drying temperature in S3 is 120° C. and the drying time is 120 minutes.

[0041] The heat-insulating and heat-retaining aerogel fiber produced in Example 1 has a fineness of 9 dtex and a density of 1.0 g / cm 3 The breaking strength was 4.05 cN / dtex, the bulkiness was 5.1 cm, the thermal conductivity coefficient was 0.02 w / m K, the moisture content was 2.3%, the evaporation rate was 0.22 g / h, the far-infrared emissivity was 0.89, the far-infrared irradiation temperature was 3.2°C, and the dyeing uniformity was grade 4.

[0042] Example 3 S1, corn flour, and ethyl orthosilicate were added to the polyester slices and stirred at a stirring speed of 500 r / min for 40 min to obtain a blended fiber material. S2. Melt spinning is used, in which the mixed fiber raw material is melted and then extruded through the spinning hole and drawn to obtain the initial fiber;

[0043] S3: The initial fiber is immersed in a dispersion, left to stand, cryogenically treated, and dissolved to obtain aerogel composite fiber, which further contains protein. organic acid The material is immersed in an auxiliary agent to react, then washed with water, pre-dried, and then re-dried to produce a heat-insulating aerogel fiber with a two-layer structure.

[0044] The particle size of the flax powder in S1 is 300 nm. The amount of flax powder added in S1 is 10 wt % of the polyester slice. The amount of ethyl orthosilicate added in S1 was 5 wt % of the polyester slices.

[0045] The process parameters for melt spinning in S2 are as follows: temperature in zone 1 is 300°C, temperature in zone 2 is 315°C, temperature in zone 3 is 310°C, and temperature in zone 4 is 305°C.

[0046] The solute of the dispersion in S3 is triethylamine, the solvent is water, and the concentration of the dispersion is 2 wt %. The standing time in S3 is 5 minutes, the temperature of the cryogenic treatment is −196° C., and the time is 7 seconds.

[0047] An organic solvent is used for elution in S3, and the organic solvent is isopropanol. Proteins in S3 organic acid In the auxiliary, wheat protein accounts for 15 wt%, citric acid accounts for 4 wt%, and the remainder is water.

[0048] In the step S3, the aerogel composite fiber is mixed with a protein-containing organic acid The reaction was carried out by immersing in the auxiliary agent, the reaction time was 5 hours, and the reaction temperature was 32°C. The preliminary drying temperature in S3 is 90° C. and the time is 60 minutes. In S3, the drying temperature is 150° C. and the drying time is 90 minutes.

[0049] The heat-insulating and heat-retaining aerogel fiber produced in Example 1 had a fineness of 0.5 dtex and a density of 0.7 g / cm 3 The breaking strength was 4.54 cN / dtex, the bulkiness was 6.1 cm, the thermal conductivity coefficient was 0.008 w / m K, the moisture content was 3.6%, the evaporation rate was 0.28 g / h, the far-infrared emissivity was 0.92, the far-infrared irradiation temperature was 4°C, and the dyeing uniformity was grade 4.

[0050] Comparative Example 1 S1, flax powder and ethyl orthosilicate are added to the dispersion, and the aerogel is obtained after standing, cryogenic treatment, and leaching.

[0051] S2. Add aerogel to polyester slices and stir for 35 minutes at a stirring speed of 600 r / min to obtain blended fiber material. Melt spinning is used to extrude the blended fiber material through the spinning hole after melting and stretching to obtain aerogel composite fiber.

[0052] S3, aerogel composite fiber containing protein organic acid The material is immersed in the auxiliary agent to react, then washed with water, and then pre-dried and re-dried to produce a heat-insulating aerogel fiber with a two-layer structure. The particle size of the flax powder in S1 is 1 μm. The amount of flax powder added in S1 is 5 wt% of the polyester slice. The amount of ethyl orthosilicate added in S1 was 3 wt % of the polyester slices.

[0053] The solute of the dispersion liquid in S1 is triethylamine, the solvent is water, and the concentration of the dispersion liquid is 1.5 wt %. The standing time in S1 was 4 minutes, the cryogenic treatment temperature was −196° C., and the time was 7 seconds. An organic solvent is used for elution in S1, and the organic solvent is isopropanol.

[0054] The process parameters for melt spinning in S2 are as follows: temperature in zone 1 is 300°C, temperature in zone 2 is 315°C, temperature in zone 3 is 310°C, and temperature in zone 4 is 305°C.

[0055] Proteins in S3 organic acid In the auxiliary, the soybean-derived protein accounts for 12 wt%, the citric acid accounts for 3 wt%, and the remainder is water. In the step S3, the aerogel composite fiber is mixed with a protein-containing organic acid The reaction time for immersion in the auxiliary and reaction is 4.5 hours, and the reaction temperature is 35°C.

[0056] The preliminary drying temperature in S3 is 70° C. and the time is 55 minutes. In S3, the drying temperature is 140° C. and the drying time is 100 minutes.

[0057] The heat-insulating aerogel fiber produced in Comparative Example 1 had a fineness of 1.5 dtex and a density of 0.9 g / cm 3The breaking strength was 2.9 cN / dtex, the bulkiness was 4.8 cm, the thermal conductivity coefficient was 0.04 w / m K, the moisture content was 1.3%, the evaporation rate was 0.15 g / h, the far-infrared emissivity was 0.83, the far-infrared irradiation temperature was 2°C, and the dyeing uniformity was grade 4.

[0058] Comparative Example 1 shows that the process of directly mixing cellulose aerogel and SiO2 aerogel with fiber raw materials, extruding them, and drawing them into fibers causes some destruction of the aerogel structure, and the crushed aerogel structure has a negative effect on the performance of the fibers. Comparative Example 2

[0059] Representative Example 1 was selected and contains the protein in the S3 step. organic acid The auxiliary immersion reaction and the subsequent washing and drying steps were omitted, and the rest were all consistent with Example 1. As Comparative Example 2, the obtained fiber did not have a two-layer structure, and the moisture content and dyeing effect of the fiber were significantly reduced. The moisture content was only 0.8%, and the dyeing uniformity was grade 1, indicating that the protein membrane outer layer greatly enhanced the moisture absorption and dyeing effect of the fiber. Comparative Example 3

[0060] Representative Example 1 was selected, and the pre-drying and re-drying treatment methods in step S3 were omitted. After washing with water, the fiber was dried at 140°C. After drying for 30 minutes, it was observed that bubbles appeared on the fiber surface. After drying for 2 hours, it was observed that fine cracks appeared on the fiber surface. By adopting the pre-drying and re-drying treatment method, the protein film was further solidified on the surface of the aerogel composite fiber, and it was possible to avoid the protein film shrinking unevenly and rapidly at high temperatures, which would cause bubbles, fine patterns, etc., and affect the appearance of the fiber.

[0061] Note: The test criteria in the examples are as follows: Mechanical properties: Measured according to GB / T 3923.1-2013. Dyeing uniformity: Measured according to "GB / T 6508-2015". Thermal conductivity: Measured in accordance with GB / T 35762-2017. Quick-drying performance: Measured according to "GB / T 21655.1-2008". Far-infrared performance: Measured according to "GB / T 30127-2013". Unless otherwise specified, all proportions described in the present invention are mass proportions, all percentages are mass percentages, and all raw materials are commercially available products.

[0062] Finally, it should be noted that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art may still modify the technical solutions described in the above embodiments or substitute some of the technical features therein with equivalents. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for producing a heat-insulating and thermal-retaining aerogel fiber, comprising: S1: Adding plant powder and silicon source auxiliary to fiber raw material and stirring for 30 to 40 minutes to obtain a mixed fiber raw material; S2: A step of extruding the mixed fiber raw material through the spinning hole and then stretching it to obtain an initial fiber; S3: A step of immersing the initial fiber in a dispersion, leaving it to stand, subjecting it to cryogenic treatment, and dissolving it to obtain an aerogel composite fiber, which is then immersed in a protein-containing organic acid auxiliary to cause a reaction, washed with water, pre-dried, and then re-dried to produce a heat-insulating and heat-retaining aerogel fiber having a two-layer structure; wherein the organic acid is citric acid, malic acid, or tannic acid. A method for producing heat-insulating aerogel fibers

2. The plant of the plant powder is selected from one or more of flax, conifer, sugarcane, cotton, seaweed, and corn; The particle size of the plant powder is 300 nm to 2 μm, The silicon source auxiliary in S1 is one or more of sodium silicate, silicon tetrachloride, methyl orthosilicate, and ethyl orthosilicate; The fiber raw material in S1 is one or more of polyester, regenerated cellulose fiber, polyurethane, nylon, and acrylic, The stirring speed is 500-800 r / min. The method for producing the heat-insulating aerogel fiber according to claim 1 .

3. The amount of plant powder added in S1 is 0.3 to 10 wt % of the active ingredient of the fiber raw material, The amount of silicon source auxiliary agent added in S1 is 1 to 5 wt% of the effective component of the fiber raw material; The method for producing the heat-insulating aerogel fiber according to claim 1 .

4. The solute of the dispersion liquid in S3 is one or more of sodium bicarbonate, ammonia monohydrate, dimethylamine, triethylamine, aniline, and pyridine, The solvent of the dispersion is water. The method for producing the heat-insulating aerogel fiber according to claim 1 .

5. The concentration of the dispersion in S3 is 0.5 to 2 wt %. The method for producing the heat-insulating aerogel fiber according to claim 1 .

6. The standing time in S3 is 3 to 5 minutes, The temperature of the cryogenic treatment in S3 is −196° C., and the time of the cryogenic treatment is 1 to 10 seconds; An organic solvent is used for elution in step S3, and the organic solvent is one or more of methanol, ethanol, isopropanol, and acetone. The method for producing the heat-insulating aerogel fiber according to claim 1 .

7. The protein-containing organic acid auxiliary in S3 contains a protein, an organic acid, and water, The protein is one or more of soybean-derived protein, wheat protein, pea protein, corn protein, and keratin protein; The method for producing the heat-insulating aerogel fiber according to claim 1 .

8. In the protein-containing organic acid auxiliary, the protein accounts for 10-15 wt %, the organic acid accounts for 2-4 wt %, and the remainder is water. The method for producing a heat-insulating and heat-retaining aerogel fiber according to claim 7.

9. In the step S3, the aerogel composite fiber is immersed in the protein-containing organic acid auxiliary for reaction for 4 to 5 hours, and the reaction temperature is 30 to 35°C. The preliminary drying temperature in S3 is 60°C to 90°C, and the time is 50 to 60 minutes. In the step S3, the drying temperature is 120 to 150°C and the drying time is 90 to 120 minutes. The method for producing a heat-insulating and heat-retaining aerogel fiber according to claim 7.