Fluffy thermal insulation aerogel fiber and preparation method therefor

Abstract

A fluffy thermal insulation aerogel fiber and a preparation method therefor, relating to the technical field of fibers. The aerogel fiber is of a double-layer structure, and in the double-layer structure, an inner layer is aerogel composite fibers containing SiO2 aerogel and cellulose aerogel, and an outer layer is a protein film. Plant powder and a silicon source additive are added into a fiber raw material for blending, and then the blended fiber raw material passes through spinneret orifices to be prepared into nascent fibers, wherein the plant powder and the silicon source additive are distributed inside the nascent fibers; the nascent fibers are immersed in a dispersion liquid and undergo steps such as ultralow temperature treatment, and then cellulose aerogel and SiO2 aerogel are uniformly generated inside the nascent fibers to obtain aerogel composite fibers; and the aerogel composite fibers are immersed in a fruit acid additive containing protein, and then the protein and fruit acid undergo a cross-linking reaction to form a protein film on the surface of the aerogel composite fibers, so as to obtain a double-layer structure in which an inner layer is the aerogel composite fibers and an outer layer is the protein film. The generation of the protein film makes the fiber more skin-friendly, and improves the moisture-absorbing properties and dyeing effect of the fiber.

Description

Fluffy heat-insulating aerogel fiber and preparation method thereof Technical Field

[0001] The present invention belongs to the field of fiber technology, and in particular relates to a fluffy heat-insulating aerogel fiber and a preparation method thereof. Background Art

[0002] Aerogels are a type of porous material derived from gels. They possess high surface area, high porosity, low density, and low thermal conductivity, and hold great promise for applications in biology, medicine, architecture, and other fields. With further research, aerogels are increasingly being used in fiber spinning. Adding aerogels to fibers and fabrics imparts lightweight warmth. SiO2 aerogels are a major focus of aerogel research in the textile field. While SiO2 aerogels have a wide range of applications, their brittle nature makes them prone to fragmentation and powder during production.

[0003] Textiles using SiO2 aerogels have low spinnability and plasticity. For example, non-woven sandwich materials are three-layered fabrics with a non-woven fabric substrate as the interlayer and an aerogel core. The non-woven fabric substrate is typically limited to polyester or polypropylene. While non-woven sandwich materials provide warmth, they are rarely used in fabric weaving and cannot be dyed due to the substrate. Furthermore, non-woven sandwich materials have low surface moisture regain and are prone to static electricity, which can be harmful to the human body. For example, they can irritate the skin, reduce moisture content, and cause symptoms such as dryness, flaking, and itching. Textiles made from non-woven sandwich materials are heavy and thick, with a single layer exceeding 0.3 cm thick, making them less comfortable to wear, limiting their development in the textile industry.

[0004] In order to make SiO2 aerogel more applicable to the textile industry, researchers have placed their breakthrough on aerogel fibers. Most common SiO2 aerogel-containing fibers on the market are made by directly blending SiO2 aerogel powder with polymer chips or spinning solution. For example, in patent number "CN202211310230.9" entitled "A Graphene Aerogel Fiber and Its Preparation Method", polyester chips are ground and crushed, and then the powder is mixed with graphene material, aerogel glass microbead material, and a modifier. After extrusion granulation, a composite masterbatch is obtained, and then melt spinning is performed. However, SiO2 aerogel is relatively brittle and its porous structure is fragile. During the spinning process, the pores of SiO2 aerogel collapse, resulting in uneven distribution of the porous structure in the fiber, affecting the performance of the fiber. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a fluffy heat-insulating aerogel fiber and a preparation method, which achieves the purpose of preventing the aerogel in the fiber from breaking and affecting the fiber performance, and improving the hygroscopicity and dyeability of the aerogel fiber.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] One of the purposes of the present invention is to provide a fluffy heat-insulating aerogel fiber, which has a double-layer structure, wherein the inner layer is an aerogel composite fiber containing SiO2 aerogel and cellulose aerogel, and the outer layer is a protein film.

[0008] A second object of the present invention is to provide a method for preparing fluffy heat-insulating aerogel fibers, the preparation method comprising the following steps:

[0009] S1. Add plant powder and silicon source additive to fiber raw material and stir for 30-40 minutes to obtain blended fiber raw material;

[0010] S2, the blended fiber raw material is extruded through a spinneret and then drawn to obtain spun fiber;

[0011] S3. Immerse the spun fibers in a dispersion, allow to stand, perform ultra-low temperature treatment, and elute to obtain an aerogel composite fiber, which is then immersed in a protein-containing fruit acid additive for reaction. After washing, the fibers are pre-dried and then dried to produce a fluffy, heat-insulating, and thermal-preserving aerogel fiber having a double-layer structure.

[0012] Preferably, the plant powder in S1 is one or more powders of flax, needles, sugarcane, cotton, seaweed, mulberry linterae, and corn, and has a particle size of 300 nm to 2 μm.

[0013] Preferably, the silicon source auxiliary agent in S1 is one or more of sodium silicate, silicon tetrachloride, methyl orthosilicate, and ethyl orthosilicate.

[0014] Preferably, the fiber of the fiber raw material in S1 is one or more of polyester, regenerated cellulose fiber, polyurethane, acrylic fiber, nylon, and polypropylene fiber.

[0015] Preferably, the stirring rate is 500-800 r / min.

[0016] Preferably, the amount of plant powder added in S1 is 0.3-10 wt % of the effective components of the fiber raw material.

[0017] Preferably, the amount of the silicon source additive in S1 is 1 to 5 wt % of the effective components of the fiber raw material.

[0018] The effective component of the cellulose fiber raw material refers to cellulose methyl in the cellulose fiber spinning solution.

[0019] Preferably, the solute of the dispersion in S3 is one or more of sodium bicarbonate, ammonia monohydrate, dimethylamine, triethylamine, aniline, and pyridine, and the solvent is water.

[0020] Preferably, the concentration of the dispersion in S3 is 0.5-2 wt %.

[0021] Preferably, the standing time in S3 is 3 to 5 minutes.

[0022] Preferably, the temperature of the ultra-low temperature treatment in S3 is -196°C, and the time is 1 to 10 seconds.

[0023] Preferably, an organic solvent is used for elution in S3, and the organic solvent is one or more of methanol, ethanol, isopropanol and acetone.

[0024] Preferably, the protein-containing fruit acid adjuvant in S3 includes protein, fruit acid and water; the protein is one or more of soy protein isolate, wheat protein, pea protein, corn protein, and keratin; and the fruit acid is one or more of citric acid, malic acid, tannic acid, and tannic acid.

[0025] Furthermore, in the protein-containing fruit acid adjuvant, protein accounts for 10-15wt%, fruit acid accounts for 2-4wt%, and the rest is water.

[0026] Preferably, the reaction time of immersing the aerogel composite fiber in the protein-containing fruit acid additive in S3 is 4 to 5 hours, and the reaction temperature is 30 to 35°C.

[0027] Preferably, the pre-drying temperature in S3 is 60-90° C. and the time is 50-60 min.

[0028] Preferably, the drying temperature in S3 is 120-150° C., and the drying time is 90-120 min.

[0029] Due to the adoption of the above technical solution, the technical effects achieved by the present invention are:

[0030] 1. The fluffy heat-insulating aerogel fiber prepared by the present invention has a fineness of 0.5-9 dtex, a density of 0.7-1.0 g / cm3, and a bulkiness of >5 cm. After being made into a fabric, the thickness of a single layer is less than 0.02 cm, making it lighter and more comfortable to wear.

[0031] 2. The fluffy heat-insulating aerogel fiber prepared by the present invention has a thermal conductivity coefficient of 0.008-0.02w / m·K (measured in accordance with GB / T 35762-2017), while the thermal conductivity coefficient of ordinary acrylic fiber is 0.032w / m·K, the thermal conductivity coefficient of ordinary polyester is 0.07w / m·K, and the thermal conductivity coefficient of hollow polyester is 0.04w / m·K. Therefore, the thermal insulation performance is better than that of ordinary fibers; the fiber has good moisture absorption and a moisture regain rate of more than 2%; the quick-drying performance is excellent, and the evaporation rate is more than 0.2g / h (measured in accordance with GB / T21655.1-2008). The fiber is lightweight and warm while absorbing moisture and drying quickly.

[0032] 3. The fluffy heat-insulating aerogel fiber prepared by the present invention has far-infrared heating performance, wherein the far-infrared emissivity is greater than 0.88, and the far-infrared radiation temperature rise is greater than 3°C (measured in accordance with GB / T 30127-2013); the dyeing performance is good, and the dyeing uniformity is not less than level 4.

[0033] 4. In the present invention, plant powder and silicon source additives are added to the fiber raw material and blended and then passed through a spinneret to form spun fibers. The plant powder and silicon source additives are distributed inside the spun fibers. After immersion in a dispersion liquid, ultra-low temperature treatment and other steps, cellulose aerogel and SiO2 aerogel are uniformly generated inside the spun fibers to obtain aerogel composite fibers. This avoids certain damage to the structure of the aerogel during the process of directly blending cellulose aerogel and SiO2 aerogel with the fiber raw material, extruding, and stretching them to form fibers, and avoids the broken aerogel structure from having adverse effects on the performance of the fiber.

[0034] 5. Immerse the aerogel composite fiber in a fruit acid additive containing protein. The protein and fruit acid undergo a cross-linking reaction to form a protein film on the surface of the aerogel composite fiber, thereby obtaining a double-layer structure with the inner layer being the aerogel composite fiber and the outer layer being the protein film. The formation of the protein film makes the fiber more skin-friendly and improves the fiber's hygroscopicity and dyeing effect.

[0035] 6. In S3, a pre-drying and then drying treatment method is adopted, and the protein film is further solidified on the surface of the aerogel composite fiber, so as to avoid the protein film from shrinking rapidly and unevenly at high temperature to produce bubbles, fine lines, etc., which affect the appearance of the fiber. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to specific embodiments. Example 1

[0037] S1. Add flax powder and tetraethyl orthosilicate to polyester chips and stir for 35 minutes at a stirring rate of 600 r / min to obtain a blended fiber raw material;

[0038] S2, melt spinning, the blended fiber raw materials are melted and extruded from the spinneret, and then drawn to obtain the nascent fiber;

[0039] S3. Immerse the spun fibers in a dispersion, allow to stand, perform ultra-low temperature treatment, and elute to obtain an aerogel composite fiber, which is then immersed in a protein-containing fruit acid additive for reaction. After washing, the fibers are pre-dried and then dried to produce a fluffy, heat-insulating, and thermal-preserving aerogel fiber having a double-layer structure.

[0040] The particle size of the flax powder in S1 is 1 μm.

[0041] The amount of flax powder added in S1 is 5wt% of the polyester chips.

[0042] The amount of ethyl orthosilicate added in S1 is 3 wt % of the polyester chips.

[0043] The process parameters of the melt spinning in S2 are: the temperature of zone 1 is 300°C, the temperature of zone 2 is 315°C, the temperature of zone 3 is 310°C, and the temperature of zone 4 is 305°C.

[0044] The solute of the dispersion in S3 is triethylamine, and the solvent is water; the concentration of the dispersion is 1.5 wt %.

[0045] The standing time in S3 is 4 minutes; the ultra-low temperature treatment temperature is -196° C. and the time is 7 seconds.

[0046] The elution in S3 is performed using an organic solvent, which is isopropanol.

[0047] In the protein-containing fruit acid adjuvant in S3, soy protein isolate accounts for 12 wt %, citric acid accounts for 3 wt %, and the rest is water.

[0048] The reaction time of the aerogel composite fiber in S3 immersed in the protein-containing fruit acid additive is 4.5 hours, and the reaction temperature is 35°C.

[0049] The pre-drying temperature in S3 is 70° C. and the time is 55 minutes.

[0050] The drying temperature in S3 is 140° C. and the drying time is 100 min.

[0051] The fluffy thermal insulation aerogel fiber prepared in Example 1 has a fineness of 1.5 dtex, a density of 0.76 g / cm3, a breaking strength of 4.4 cN / dtex, and a bulkiness of 5.8 cm; a thermal conductivity coefficient of 0.012 w / m·K, a regain of 3%, an evaporation rate of 0.25 g / h, a far-infrared emissivity of 0.91, a far-infrared radiation temperature rise of 3.6°C, and a dyeing uniformity of level 4. Example 2

[0052] S1. Add cotton powder and sodium silicate to polyester chips and stir for 30 minutes at a stirring rate of 800 r / min to obtain a blended fiber raw material;

[0053] S2, melt spinning, the blended fiber raw materials are melted and extruded from the spinneret, and then drawn to obtain the nascent fiber;

[0054] S3. Immerse the spun fibers in a dispersion, allow to stand, perform ultra-low temperature treatment, and elute to obtain an aerogel composite fiber, which is then immersed in a protein-containing fruit acid additive for reaction. After washing, the fibers are pre-dried and then dried to produce a fluffy, heat-insulating, and thermal-preserving aerogel fiber having a double-layer structure.

[0055] The particle size of the flax powder in S1 is 2 μm.

[0056] The amount of flax powder added in S1 is 0.3 wt% of the polyester chips.

[0057] The amount of ethyl orthosilicate added in S1 is 1 wt % of the polyester chips.

[0058] The process parameters of the melt spinning in S2 are: the temperature of zone 1 is 300°C, the temperature of zone 2 is 315°C, the temperature of zone 3 is 310°C, and the temperature of zone 4 is 305°C.

[0059] The solute of the dispersion in S3 is triethylamine, and the solvent is water; the concentration of the dispersion is 0.5 wt %.

[0060] The standing time in S3 is 3 minutes; the ultra-low temperature treatment temperature is -196° C. and the time is 1 second.

[0061] The elution in S3 is performed using an organic solvent, which is ethanol.

[0062] In the protein-containing fruit acid adjuvant in S3, corn protein accounts for 10 wt%, tannic acid accounts for 2 wt%, and the rest is water.

[0063] The reaction time of the aerogel composite fiber in S3 immersed in the protein-containing fruit acid additive is 4 hours, and the reaction temperature is 30°C.

[0064] The pre-drying temperature in S3 is 60° C. and the time is 50 minutes.

[0065] The drying temperature in S3 is 120° C. and the drying time is 120 min.

[0066] The fluffy thermal insulation aerogel fiber prepared in Example 1 has a fineness of 9 dtex, a density of 1.0 g / cm3, a breaking strength of 4.05 cN / dtex, and a bulkiness of 5.1 cm; a thermal conductivity coefficient of 0.02 w / m·K, a regain of 2.3%, an evaporation rate of 0.22 g / h, a far-infrared emissivity of 0.89, a far-infrared radiation temperature rise of 3.2°C, and a dyeing uniformity of level 4. Example 3

[0067] S1. Add corn flour and ethyl orthosilicate to polyester chips and stir for 40 minutes at a stirring rate of 500 r / min to obtain a blended fiber raw material;

[0068] S2, melt spinning, the blended fiber raw materials are melted and extruded from the spinneret, and then drawn to obtain the nascent fiber;

[0069] S3. Immerse the spun fibers in a dispersion, allow to stand, perform ultra-low temperature treatment, and elute to obtain an aerogel composite fiber, which is then immersed in a protein-containing fruit acid additive for reaction. After washing, the fibers are pre-dried and then dried to produce a fluffy, heat-insulating, and thermal-preserving aerogel fiber having a double-layer structure.

[0070] The particle size of the flax powder in S1 is 300 nm.

[0071] The amount of flax powder added in S1 is 10 wt% of the polyester chips.

[0072] The amount of ethyl orthosilicate added in S1 is 5 wt % of the polyester chips.

[0073] The process parameters of the melt spinning in S2 are: the temperature of zone 1 is 300°C, the temperature of zone 2 is 315°C, the temperature of zone 3 is 310°C, and the temperature of zone 4 is 305°C.

[0074] The solute of the dispersion in S3 is triethylamine, and the solvent is water; the concentration of the dispersion is 2 wt %.

[0075] The standing time in S3 is 5 minutes; the ultra-low temperature treatment temperature is -196° C. and the time is 7 seconds.

[0076] The elution in S3 is performed using an organic solvent, which is isopropanol.

[0077] In the protein-containing fruit acid adjuvant in S3, wheat protein accounts for 15wt%, citric acid accounts for 4wt%, and the rest is water.

[0078] The reaction time of the aerogel composite fiber in S3 immersed in the protein-containing fruit acid additive is 5 hours, and the reaction temperature is 32°C.

[0079] The pre-drying temperature in S3 is 90° C. and the time is 60 minutes.

[0080] The drying temperature in S3 is 150° C. and the drying time is 90 minutes.

[0081] The fluffy thermal insulation aerogel fiber prepared in Example 1 has a fineness of 0.5 dtex, a density of 0.7 g / cm3, a breaking strength of 4.54 cN / dtex, and a bulkiness of 6.1 cm; a thermal conductivity coefficient of 0.008 w / m·K, a regain of 3.6%, an evaporation rate of 0.28 g / h, a far-infrared emissivity of 0.92, a far-infrared radiation temperature rise of 4°C, and a dyeing uniformity of level 4.

[0082] Comparative Example 1

[0083] S1. Adding flax powder and ethyl orthosilicate to a dispersion liquid, allowing it to stand, ultra-low temperature treating it, and eluting it to obtain an aerogel;

[0084] S2. Adding the aerogel to the polyester chips and stirring for 35 minutes at a stirring rate of 600 r / min to obtain a blended fiber raw material; melt spinning is performed, and the blended fiber raw material is extruded from the spinneret after being melted, and then drawn to obtain an aerogel composite fiber;

[0085] S3. Immersing the aerogel composite fiber in a protein-containing fruit acid additive for reaction, washing it with water, and then pre-drying and drying it to produce a fluffy heat-insulating aerogel fiber with a double-layer structure.

[0086] The particle size of the flax powder in S1 is 1 μm.

[0087] The amount of flax powder added in S1 is 5wt% of the polyester chips.

[0088] The amount of ethyl orthosilicate added in S1 is 3 wt % of the polyester chips.

[0089] The solute of the dispersion in S1 is triethylamine, and the solvent is water; the concentration of the dispersion is 1.5 wt %.

[0090] The standing time in S1 is 4 minutes; the ultra-low temperature treatment temperature is -196° C. and the time is 7 seconds.

[0091] The elution in S1 is performed using an organic solvent, which is isopropanol.

[0092] The process parameters of the melt spinning in S2 are: the temperature of zone 1 is 300°C, the temperature of zone 2 is 315°C, the temperature of zone 3 is 310°C, and the temperature of zone 4 is 305°C.

[0093] In the protein-containing fruit acid adjuvant in S3, soy protein isolate accounts for 12 wt %, citric acid accounts for 3 wt %, and the rest is water.

[0094] The reaction time of the aerogel composite fiber in S3 immersed in the protein-containing fruit acid additive is 4.5 hours, and the reaction temperature is 35°C.

[0095] The pre-drying temperature in S3 is 70° C. and the time is 55 minutes.

[0096] The drying temperature in S3 is 140° C. and the drying time is 100 min.

[0097] The fluffy heat-insulating aerogel fiber prepared in Comparative Example 1 has a fineness of 1.5 dtex, a density of 0.9 g / cm3, a breaking strength of 2.9 cN / dtex, and a fluffiness of 4.8 cm; the thermal conductivity coefficient is 0.04 w / m·K, the regain is 1.3%, the evaporation rate is 0.15 g / h, the far-infrared emissivity is 0.83, the far-infrared radiation temperature rise is 2°C, and the dyeing uniformity is level 4.

[0098] Comparative Example 1 shows that directly blending cellulose aerogel and SiO2 aerogel with fiber raw materials, extruding, and drawing them into fibers will cause certain damage to the structure of the aerogel, and the broken aerogel structure will have an adverse effect on the performance of the fiber.

[0099] Comparative Example 2

[0100] Representative Example 1 was selected, and the immersion in the protein-containing fruit acid additive for reaction and the subsequent washing and drying steps in step S3 were removed. The rest were consistent with Example 1. As Comparative Example 2, the obtained fiber did not have a double-layer structure, and the moisture regain and dyeing effect of the fiber were significantly reduced, with the moisture regain being only 0.8% and the dyeing uniformity being level 1, indicating that the outer layer of the protein membrane greatly enhanced the hygroscopicity and dyeing effect of the fiber.

[0101] Comparative Example 3

[0102] Representative Example 1 was selected, and the pre-drying and re-drying treatment methods in step S3 were removed. After washing with water, the fiber was dried at 140°C. After drying for 30 minutes, bubbles appeared on the fiber surface. After drying for 2 hours, fine cracks appeared on the fiber surface. This shows that the pre-drying and re-drying treatment method is adopted, and the protein film is further solidified on the surface of the aerogel composite fiber, avoiding the protein film from shrinking rapidly and unevenly at high temperature to produce bubbles, fine lines, etc., which affect the appearance of the fiber.

[0103] Note: The test standards in the examples are:

[0104] Mechanical properties: Determined in accordance with GB / T 3923.1-2013.

[0105] Dyeing evenness: measured in accordance with GB / T 6508-2015.

[0106] Thermal conductivity: measured in accordance with GB / T 35762-2017.

[0107] Quick-drying performance: measured in accordance with GB / T 21655.1-2008.

[0108] Far infrared performance: measured in accordance with GB / T 30127-2013.

[0109] Unless otherwise specified, the ratios and percentages described in the present invention are all by mass; all raw materials are commercially available.

[0110] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A fluffy heat-insulating aerogel fiber, characterized in that, The aerogel fiber has a double-layer structure, where the inner layer is an aerogel composite fiber containing SiO2 aerogel and cellulose aerogel, and the outer layer is a protein film.

2. A preparation method of fluffy heat-insulating aerogel fibers, characterized in that, The preparation method includes the following steps: S1. Add plant powder and a silicon source auxiliary agent to the fiber raw material and stir for 30 - 40 min to obtain a blended fiber raw material; S2. After the blended fiber raw material is extruded through a spinneret hole, it is drawn to obtain a primary fiber; S3. Immerse the primary fiber in a dispersion liquid, and after standing, cryogenic treatment, and elution, an aerogel composite fiber is obtained. Then immerse it in a fruit acid auxiliary agent containing protein for reaction, and after washing with water, use the treatment methods of pre-drying and then drying to produce a fluffy heat-insulating and heat-preserving aerogel fiber with a double-layer structure.

3. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, The plant powder in S1 is one or more powders of flax, coniferous leaves, sugarcane, cotton, seaweed, Phellinus linteus, corn, etc., with a particle size of 300 nm - 2 μm; The silicon source auxiliary agent in S1 is one or more of sodium silicate, silicon tetrachloride, methyl orthosilicate, and ethyl orthosilicate; The fiber of the fiber raw material in S1 is one or more of polyester, regenerated cellulose fiber, polyurethane, acrylic fiber, nylon, and polypropylene; The stirring rate is 500 - 800 r / min.

4. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, The addition amount of the plant powder in S1 is 0.3 - 10 wt% of the effective component of the fiber raw material; The addition amount of the silicon source auxiliary agent in S1 is 1 - 5 wt% of the effective component of the fiber raw material.

5. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, 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.

6. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, The concentration of the dispersion liquid in S3 is 0.5 - 2 wt%.

7. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, The standing time in S3 is 3 - 5 min; The temperature of the cryogenic treatment in S3 is -196 °C, and the time is 1 - 10 s; The elution in S3 uses an organic solvent, and the organic solvent is one or more of methanol, ethanol, isopropanol, and acetone.

8. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, The fruit acid auxiliary agent containing protein in S3 includes protein, fruit acid, and water; the protein is one or more of soy protein isolate, wheat protein, pea protein, corn protein, and keratin; the fruit acid is one or more of citric acid, malic acid, tannic acid, and tannin.

9. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, In the fruit acid auxiliary agent containing protein, the protein accounts for 10 - 15 wt%, the fruit acid accounts for 2 - 4 wt%, and the rest is water.

10. The preparation method of a fluffy heat-insulating aerogel fiber according to claim 2, characterized in that, The reaction time for the aerogel composite fiber to be immersed in the fruit acid auxiliary agent containing protein in S3 is 4 - 5 h, and the reaction temperature is 30 - 35 °C; The temperature of the pre-drying in S3 is 60 - 90 °C, and the time is 50 - 60 min; The drying temperature in S3 is 120 - 150 °C, and the time is 90 - 120 min.