Phase change microcapsule doped flexible cooling fiber fabric and preparation method thereof

Abstract

The invention belongs to the technical field of composite fiber materials, and relates to a functional thermal management fabric, in particular to a phase change microcapsule doped flexible cooling fiber fabric and a preparation method thereof. The fabric has a controllable double-layer structure and is formed by assembling nanofibers and micro-nanofibers doped with a large number of phase change microcapsules. Wherein the micro-nano fiber layer has relatively high sunlight reflectivity and atmospheric window wave band emissivity, and shows an excellent radiation cooling effect; the microcapsule content of the nanofiber layer doped with a large amount of phase change microcapsules is not less than 10 wt%, and the nanofiber layer has no rupture phenomenon, has high heat storage capacity, not only makes up for the deficiency of radiation cooling capacity, but also effectively slows down temperature fluctuation. The radiation cooling technology and the phase change latent heat technology are combined, so that the long-time temperature control performance of the fabric is realized, and the thermal shock resistance is enhanced. In addition, the fabric also has excellent mechanical property, flexibility, washability, air permeability, moisture penetrability and sunscreen property.

Description

Technical Field

[0001] The invention belongs to the technical field of composite fiber materials, relates to functionalized thermal management fabrics, and in particular to a flexible cooling fiber fabric doped with phase change microcapsules and a preparation method thereof. Background Art

[0002] In recent years, with global warming, high temperature weather has occurred frequently, with a trend of large temperature fluctuations and long duration. This not only increases the indoor cooling load and the energy consumption of refrigeration equipment, but also poses a serious threat to the health and life safety of outdoor workers. Traditional clothing, including sun protection clothing, cannot meet the needs of personal thermal comfort in high temperature environments. In order to solve the impact of temperature fluctuations on human thermal comfort in high temperature environments, it is urgent to develop fabrics with both cooling and temperature control properties to effectively regulate human thermal management.

[0003] Radiative cooling fabrics with high solar reflectivity are used to dissipate heat from the human body. However, in a high-temperature environment with drastic temperature fluctuations, this type of radiative cooling fabric has poor thermal shock resistance and cannot maintain normal body temperature, leading to heat stress in the human body. At present, the combination of radiative cooling technology and phase change material doping technology has prepared fabrics with both cooling and phase change latent heat properties. However, phase change fabrics prepared using doping technologies such as cross-linking deposition, blending, and composite spinning have defects such as low doping amount, easy leakage, and poor flexibility, so that the existing phase change fabrics with radiative cooling performance have a short temperature control time, and there are still huge challenges in maintaining human thermal comfort. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a flexible cooling fiber fabric doped with phase change microcapsules and a preparation method thereof, and to construct an effective method for preparing a large number of flexible cooling fiber fabrics doped with phase change microcapsules. Compared with the prior art, the method has the advantages of simplicity, environmental protection, energy saving and emission reduction.

[0005] In order to solve the above problems, the present invention considers that a fiber fabric with a hierarchical structure constructed on demand is prepared in sequence by electrospinning technology, which is composed of a large number of phase change microcapsules doped with nanofiber layers and micro-nanofiber layers. The doped phase change microcapsules do not break, which not only improves the phase change heat storage performance, but also achieves efficient cooling performance and thermal shock resistance in combination with radiation cooling fibers. In addition, the phase change cooling fabric prepared by electrospinning technology also has excellent flexibility, mechanical properties, washability and breathability. The fabric provides a basic guarantee for protecting the human body from the effects of heat stress and expands the application of the technology combining radiation cooling with latent heat storage.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An object of the present invention is to provide a phase-change microcapsule-doped flexible cooling fiber fabric having a hierarchical structure, wherein the flexible cooling fiber fabric is constructed on demand from a nanofiber layer doped with phase-change microcapsules having heat storage properties and a micro-nanofiber layer having cooling properties.

[0008] In the preferred disclosed example of the present invention, the thickness of the phase change microcapsule doped nanofiber layer is 200-1000 μm, and it has high phase change heat storage performance, wherein the content of phase change microcapsules is not less than 10wt%, a large number of phase change microcapsules are interwoven in the nanofiber network, and the particle size of the phase change microcapsules is 1-15 μm.

[0009] In the preferred disclosed examples of the present invention, the micro-nano fiber layer has a thickness of 200 to 800 μm, has high solar reflectivity and infrared emissivity, and the length of the micro-nano fiber is not less than 100 μm, and the particle size is 0.1 to 5 μm.

[0010] Another object of the present invention is to disclose a method for preparing the above-mentioned phase change microcapsule-doped flexible cooling fiber fabric, comprising the following steps:

[0011] a), according to the solid-solid-liquid ratio of phase change microcapsules, organic polymers and spinning solvents of 1:9:180-2:1:4 g / g / mL, preferably 3:2:18 g / g / mL (Example 1), the organic polymer is completely dissolved in 50% of the spinning solvent to form a spinning solution, the phase change microcapsules are uniformly dispersed in the remaining 50% of the spinning solvent, and then transferred to the above spinning solution, and then injected into a syringe, and the solution is spun into a porous phase change microcapsule-doped nanofiber membrane under certain conditions by electrospinning technology;

[0012] b) According to the solid-liquid ratio of the organic polymer with radiation cooling performance to the spinning solvent of 1:20 to 3:8 g / mL, preferably 2:23 g / mL (Example 1), the organic polymer with radiation cooling performance is dissolved in the spinning solvent to form a spinning solution, which is then injected into a syringe, and the solution is spun onto the surface of the porous phase change microcapsule-doped nanofiber membrane using electrospinning technology to form a micro-nano fiber membrane, and the phase change microcapsule-doped flexible cooling fiber fabric is obtained by vacuum drying at 30 to 80°C for 4 to 28 hours.

[0013] In a preferred disclosed example of the present invention, the phase change microcapsule in step a) is a core-shell material, wherein the shell material includes polyurethane, polymethyl methacrylate, silicon dioxide and ferrosoferric oxide; the core material includes one or more combinations of aliphatic hydrocarbons, fatty acids and fatty alcohols, and the content thereof is not less than 20wt%.

[0014] In a preferred embodiment of the present invention, the organic polymer in step a) includes one or more combinations of polyvinyl alcohol, polyvinyl butyral resin and polyvinyl pyrrolidone.

[0015] In a preferred disclosed embodiment of the present invention, the spinning solvent in step a) includes one or more combinations of methanol, ethanol, N,N-dimethylformamide and acetone.

[0016] In the preferred disclosed example of the present invention, the certain conditions in step a) include an electrospinning voltage of 10 to 25 kV, a propulsion speed of 0.005 to 0.02 mm / s, a distance of 5 to 16 cm, and a syringe needle of 17 to 22 gauge.

[0017] In a preferred disclosed example of the present invention, the organic polymer with radiation cooling performance in step b) includes one or more combinations of polyvinylidene fluoride hexafluoropropylene, polyvinylidene fluoride, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral resin, polymethyl methacrylate and polyethylene terephthalate.

[0018] In a preferred disclosed embodiment of the present invention, the spinning solvent in step b) includes one or more combinations of N,N-dimethylformamide, N,N-diethylformamide, acetone, ethanol and tetrahydrofuran.

[0019] Features of the present invention:

[0020] (1) In view of the problems of easy leakage, poor flexibility and washability of existing phase change fabrics, the present invention selects stable phase change microcapsules to be doped in flexible nanofiber materials, which have excellent flexibility and washability;

[0021] (2) In view of the problems of low doping amount and leakage in the current doping phase change material technology, the present invention proposes a simple electrospinning method to dope a large number of phase change microcapsules into nanofibers to improve the phase change heat storage performance;

[0022] (3) In view of the influence of temperature fluctuation on heat stress of human body in high temperature environment, the present invention provides a flexible cooling fiber fabric doped with phase change microcapsules with high efficiency cooling performance and heat shock resistance.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention proposes an effective method for preparing a flexible cooling fiber fabric doped with a large number of phase change microcapsules. Compared with the prior art, the method has the advantages of simplicity, environmental protection, energy saving and emission reduction, and is expected to be industrialized. The fabric is composed of a double-layer fiber membrane, the outer layer is a micro-nano fiber membrane, which has a high solar reflectivity and infrared emissivity, and exhibits an excellent radiation cooling effect; the inner layer is a nanofiber membrane doped with a large number of phase change microcapsules, the microcapsules have no rupture phenomenon, and have a high heat storage capacity, which not only makes up for the lack of radiation cooling capacity, but also effectively slows down temperature fluctuations. The combination of phase change heat storage and radiation cooling performance improves the long-term temperature control performance of the fabric and enhances the ability to resist thermal shock. In addition, the fabric also has excellent cyclic stability and thermal stability, mechanical properties, flexibility, washability, air permeability, moisture permeability and sun protection. The present invention provides an effective preparation method for a fabric doped with a large number of phase change microcapsules for human thermal management, and the combination of radiation cooling and phase change latent heat technology in an environment with severe temperature fluctuations achieves human thermal comfort. The technology and application have potential economic value and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 .Scanning electron microscope images of the two surfaces of the flexible cooling fiber fabric doped with phase change microcapsules; a and b are low-magnification and high-magnification images of the nanofiber layer doped with phase change microcapsules, respectively; c and d are low-magnification and high-magnification images of the micro-nanofiber layer, respectively. DETAILED DESCRIPTION

[0026] On the whole, the present invention provides a flexible cooling fiber fabric doped with a large number of phase change microcapsules and a preparation method thereof. The fabric has a controllable double-layer structure, which is assembled from nanofibers and micro-nanofibers doped with a large number of phase change microcapsules. Among them, the micro-nano fiber layer has a high solar reflectivity and atmospheric window band emissivity, showing an excellent radiation cooling effect; the microcapsule content of the nanofiber layer doped with a large number of phase change microcapsules is not less than 10wt%, and there is no cracking phenomenon, and it has a high heat storage capacity, which not only makes up for the lack of radiation cooling capacity, but also effectively slows down temperature fluctuations. The combination of radiation cooling technology and phase change latent heat technology realizes the long-term temperature control performance of the fabric and enhances the ability to resist thermal shock. In addition, the fabric also has excellent mechanical properties, flexibility, washability, air permeability, moisture permeability and sun protection. The preparation method of the fabric is simple, environmentally friendly, and is expected to be industrialized. In view of the problem of human heat stress in a high-temperature environment with large temperature fluctuations, the present invention provides an effective preparation method for a cooling fabric doped with a large number of phase change microcapsules, and the fabric effectively realizes human thermal management

[0027] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Any features such as preparation means, materials, structures or composition ratios not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0028] Unless otherwise defined, the terms (including technical terms) used herein should be interpreted as having the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It will also be understood that the terms used herein should be interpreted as having the meaning consistent with their meanings in the content of this specification and related technologies, and should not be interpreted in an idealized or excessive form unless specifically defined as such herein.

[0029] Example 1

[0030] In this embodiment, a method for preparing a phase change microcapsule-doped flexible cooling fiber fabric comprises the following steps:

[0031] a), weigh 1.67g of polyvinyl butyral resin and completely dissolve it in 15mL of anhydrous ethanol, and stir it at 35°C for 4h to obtain a transparent spinning solution; weigh 2.5g of phase change microcapsules (core: octadecane paraffin, shell: polymethyl methacrylate) and disperse them in 15mL of anhydrous ethanol, stir at room temperature for 20min to obtain a uniform dispersion; then, slowly drop the dispersion into the spinning solution while stirring, and continue stirring at room temperature for 2h to obtain a uniformly dispersed spinning solution; finally, transfer the spinning solution to a syringe and obtain a phase change microcapsule-doped nanofiber membrane by electrospinning (wherein the syringe needle is No. 18, the voltage is 20kV, the propulsion speed is 0.015mm / s, and the distance is 10cm);

[0032] b) Weigh 1.3 g of polyvinylidene fluoride hexafluoropropylene and dissolve it in a mixed solution of 15 mL of acetone and N,N-dimethylformamide (mass ratio is 3:7), and magnetically stir it at 38°C for 5 hours to form a transparent spinning solution. Use a syringe to draw 20 mL of the spinning solution, and form a micro-nano fiber membrane on the surface of the nanofiber membrane doped with phase change microcapsules by electrospinning (wherein the syringe needle is No. 20, the voltage is 16 kV, the propulsion speed is 0.005 mm / s, and the distance is 12 cm), and vacuum dry it at 45°C for 10 hours to obtain a flexible cooling fiber fabric doped with phase change microcapsules.

[0033] Among them, the thickness of the outer micro-nano fiber membrane is 400μm, its solar reflectivity is 91.1%, and its atmospheric window band emissivity is 96.0%; the thickness of the inner layer of nanofiber membrane doped with phase change microcapsules is 500μm, its heat storage phase change enthalpy is 92.6J / g, and the heat storage time is 60min. The cooling effect of the fabric is 6.5℃ lower than the ambient temperature.

[0034] Figure 1 The SEM images of the two surfaces of the flexible cooling fiber fabric doped with phase change microcapsules are shown. Figure 1 a is a nanofiber layer doped with phase change microcapsules. The phase change microcapsules are randomly distributed and there is no sign of rupture on the surface, indicating that there is no leakage of the microcapsules during the electrospinning process. Figure 1 As shown in b, it has good mechanical stability. Figure 1 c is the micro-nano fiber layer. The ultra-long fibers are randomly interwoven to form a dense network structure with strong physical entanglement, which is beneficial to improve the flexibility and mechanical properties of the fiber fabric. Figure 1 As shown in b, this is conducive to enhancing Mie scattering and thus improving the reflectivity in the solar band. The results show that the flexible cooling fiber fabric doped with phase change microcapsules was successfully prepared.

[0035] Example 2

[0036] In this embodiment, a method for preparing a phase change microcapsule-doped flexible cooling fiber fabric comprises the following steps:

[0037] a), weigh 1.74g of polyvinyl alcohol and completely dissolve it in 20mL of methanol, and stir it at 35°C for 4h to obtain a transparent spinning solution; weigh 1.74g of phase change microcapsules (core: octadecane paraffin, shell: polyurethane) and disperse them in 20mL of methanol, stir them at room temperature for 20min to obtain a uniform dispersion; then, slowly drop the dispersion into the spinning solution while stirring, and continue stirring at room temperature for 2h to obtain a uniformly dispersed spinning solution; finally, transfer the spinning solution to a syringe and obtain a phase change microcapsule-doped nanofiber membrane by electrospinning (wherein the syringe needle is No. 20, the voltage is 18kV, the propulsion speed is 0.008mm / s, and the distance is 12cm);

[0038] b) Weigh 1.13 g of polyvinylidene fluoride and dissolve it in 15 mL of N,N-dimethylformamide. Stir magnetically at 35°C for 5 hours to form a transparent spinning solution. Use a syringe to draw 20 mL of the spinning solution. Electrospinning is used to form a micro-nano fiber membrane on the surface of the nanofiber membrane doped with phase change microcapsules (wherein the syringe needle is No. 19, the voltage is 18 kV, the propulsion speed is 0.003 mm / s, and the distance is 15 cm). Vacuum dry at 45°C for 10 hours to obtain a flexible cooling fiber fabric doped with phase change microcapsules.

[0039] Among them, the thickness of the outer micro-nano fiber membrane is 200μm, its solar reflectivity is 90.2%, and its atmospheric window band emissivity is 93.1%. The thickness of the inner layer of nanofiber membrane doped with phase change microcapsules is 1000μm, its heat storage phase change enthalpy is 76.8J / g, and the heat storage time is 50min. The cooling effect of the fabric is 6.2℃ lower than the ambient temperature.

[0040] Example 3

[0041] In this embodiment, a method for preparing a phase change microcapsule-doped flexible cooling fiber fabric comprises the following steps:

[0042] a), weigh 1.98g of polyvinyl pyrrolidone and completely dissolve it in 20mL of anhydrous ethanol, and stir it at 35°C for 4h to obtain a transparent spinning solution; weigh 4.62g of phase change microcapsules (core: octadecane paraffin, shell: silica) and disperse them in 20mL of anhydrous ethanol, stir them at room temperature for 20min to obtain a uniform dispersion; then, slowly drop the dispersion into the spinning solution while stirring, and continue stirring at room temperature for 2h to obtain a uniformly dispersed spinning solution; finally, transfer the spinning solution to a syringe and obtain a phase change microcapsule-doped nanofiber membrane by electrospinning (wherein the syringe needle is No. 17, the voltage is 23kV, the propulsion speed is 0.02mm / s, and the distance is 10cm);

[0043] b) Weigh 3.75 g of polyvinyl alcohol and dissolve it in 10 mL of anhydrous ethanol. Stir magnetically at 38 ° C for 5 hours to form a transparent spinning solution. Use a syringe to draw 20 mL of the spinning solution. Electrospinning is used to form a micro-nano fiber membrane on the surface of the nanofiber membrane doped with phase change microcapsules (wherein the syringe needle is No. 19, the voltage is 17 kV, the propulsion speed is 0.008 mm / s, and the distance is 12 cm). Vacuum dry at 45 ° C for 10 hours to obtain a flexible cooling fiber fabric doped with phase change microcapsules.

[0044] Among them, the thickness of the outer micro-nano fiber membrane is 700μm, its solar reflectivity is 94.3%, and its atmospheric window band emissivity is 95.2%. The thickness of the inner layer of nanofiber membrane doped with phase change microcapsules is 400μm, its heat storage phase change enthalpy is 106.9J / g, and the heat storage time is 75min. The cooling effect of the fabric is 8.7℃ lower than the ambient temperature.

[0045] Example 4

[0046] In this embodiment, a method for preparing a phase change microcapsule-doped flexible cooling fiber fabric comprises the following steps:

[0047] a), weigh 9g of polyvinyl butyral resin and completely dissolve it in 18mL of methanol, and stir it at 35°C for 4h to obtain a transparent spinning solution; weigh 18g of phase change microcapsules (core: octadecane paraffin, shell: polymethyl methacrylate) and disperse them in 18mL of methanol, stir them at room temperature for 20min to obtain a uniform dispersion; then, slowly drop the dispersion into the spinning solution while stirring, and continue stirring at room temperature for 2h to obtain a uniformly dispersed spinning solution; finally, transfer the spinning solution to a syringe and obtain a phase change microcapsule-doped nanofiber membrane by electrospinning (wherein the syringe needle is No. 18, the voltage is 21kV, the propulsion speed is 0.01mm / s, and the distance is 10cm);

[0048] b) Weigh 1.48 g of polyvinylidene fluoride hexafluoropropylene and dissolve it in 15 mL of N,N-diethylformamide, and magnetically stir it at 38°C for 5 hours to form a transparent spinning solution. Use a syringe to draw 20 mL of the spinning solution, and form a micro-nano fiber membrane on the surface of the nanofiber membrane doped with phase change microcapsules by electrospinning (wherein the syringe needle is No. 19, the voltage is 18 kV, the propulsion speed is 0.008 mm / s, and the distance is 12 cm), and vacuum dry it at 45°C for 10 hours to obtain a flexible cooling fiber fabric doped with phase change microcapsules.

[0049] Among them, the thickness of the outer micro-nano fiber membrane is 600μm, its solar reflectivity is 93.2%, and its atmospheric window band emissivity is 94.0%. The thickness of the inner layer of nanofiber membrane doped with phase change microcapsules is 200μm, its heat storage phase change enthalpy is 62.1J / g, and the heat storage time is 45min. The cooling effect of the fabric is 7.6℃ lower than the ambient temperature.

[0050] Example 5

[0051] In this embodiment, a method for preparing a phase change microcapsule-doped flexible cooling fiber fabric comprises the following steps:

[0052] a), weigh 1.0g of polyvinyl alcohol and completely dissolve it in 30mL of methanol, and stir it at 35°C for 4h to obtain a transparent spinning solution; weigh 0.34g of phase change microcapsules (core: octadecane paraffin, shell: polyurethane) and disperse them in 30mL of methanol, stir them at room temperature for 20min to obtain a uniform dispersion; then, slowly drop the dispersion into the spinning solution while stirring, and continue stirring at room temperature for 2h to obtain a uniformly dispersed spinning solution; finally, transfer the spinning solution to a syringe and obtain a phase change microcapsule-doped nanofiber membrane by electrospinning (where the syringe needle is No. 22, the voltage is 15kV, the propulsion speed is 0.005mm / s, and the distance is 12cm);

[0053] b) Weigh 0.75 g of polyvinylidene fluoride and dissolve it in 15 mL of N,N-dimethylformamide, and magnetically stir it at 38°C for 3 hours to form a transparent spinning solution. Use a syringe to draw 20 mL of the spinning solution, and form a micro-nano fiber membrane on the surface of the nanofiber membrane doped with phase change microcapsules by electrospinning (wherein the syringe needle is No. 21, the voltage is 15 kV, the propulsion speed is 0.0005 mm / s, and the distance is 15 cm). Vacuum dry it at 45°C for 10 hours to obtain a flexible cooling fiber fabric doped with phase change microcapsules.

[0054] Among them, the thickness of the outer micro-nano fiber membrane is 500μm, its solar reflectivity is 92.4%, and its atmospheric window band emissivity is 93.7%; the thickness of the inner layer of nanofiber membrane doped with phase change microcapsules is 800μm, its heat storage phase change enthalpy is 46.1J / g, and the heat storage time is 35min. The cooling effect of the fabric is 7.0℃ lower than the ambient temperature.

[0055] Example 6

[0056] In this embodiment, a method for preparing a phase change microcapsule-doped flexible cooling fiber fabric comprises the following steps:

[0057] a), weigh 1.74g polyvinyl pyrrolidone and completely dissolve it in 20mL of anhydrous ethanol, and stir it at 35°C for 4h to obtain a transparent spinning solution; weigh 2.13g phase change microcapsules (core: octadecane paraffin, shell: silica) and disperse them in 20mL of anhydrous ethanol, stir them at room temperature for 20min to obtain a uniform dispersion; then, slowly drop the dispersion into the spinning solution while stirring, and continue stirring at room temperature for 2h to obtain a uniformly dispersed spinning solution; finally, transfer the spinning solution to a syringe and obtain a phase change microcapsule-doped nanofiber membrane by electrospinning (wherein the syringe needle is No. 19, the voltage is 19kV, the propulsion speed is 0.009mm / s, and the distance is 10cm);

[0058] b) Weigh 1.57 g of polyvinyl alcohol and dissolve it in 15 mL of anhydrous ethanol. Stir magnetically at 38 ° C for 5 hours to form a transparent spinning solution. Use a syringe to draw 20 mL of the spinning solution. Electrospinning is used to form a micro-nano fiber membrane on the surface of the nanofiber membrane doped with phase change microcapsules (wherein the syringe needle is No. 19, the voltage is 16 kV, the propulsion speed is 0.005 mm / s, and the distance is 12 cm). Vacuum dry at 45 ° C for 10 hours to obtain a flexible cooling fiber fabric doped with phase change microcapsules.

[0059] Among them, the thickness of the outer micro-nano fiber membrane is 800μm, its solar reflectivity is 93.6%, and its atmospheric window band emissivity is 94.5%. The thickness of the inner phase change microcapsule doped nanofiber membrane is 700μm, its heat storage phase change enthalpy is 83.9J / g, and the heat storage time is 55min. The cooling effect of the fabric is 8.1℃ lower than the ambient temperature. The above description of the embodiments is to facilitate ordinary technicians in this technical field to understand and use the invention. It is obvious that those familiar with the technology in this field can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A phase-change microcapsule-doped flexible cooling fiber fabric having a hierarchical structure, characterized in that: The flexible cooling fiber fabric is constructed by a phase-change microcapsule-doped nanofiber layer with heat storage performance and a micro-nano fiber layer with cooling performance.

2. The phase-change microcapsule-doped flexible cooling fiber fabric according to claim 1, characterized in that: The thickness of the phase change microcapsule doped nanofiber layer is 200 to 1000 μm; In the phase-change microcapsule-doped nanofiber layer, the content of the phase-change microcapsules is not less than 10 wt %, the phase-change microcapsules are interwoven in the nanofiber network, and the particle size of the phase-change microcapsules is 1-15 μm.

3. The phase change microcapsule-doped flexible cooling fiber fabric according to claim 1, characterized in that: The thickness of the micro-nano fiber layer is 100-800 μm, the length of the micro-nano fiber is not less than 100 μm, and the particle size is 0.1-5 μm.

4. A method for preparing the flexible cooling fiber fabric according to any one of claims 1 to 3, characterized in that: The steps include: a), according to the solid-solid-liquid ratio of phase change microcapsules, organic polymers, and spinning solvents of 1:9:180 to 9:1:4 g / g / mL, the organic polymer is completely dissolved in 50wt% of the spinning solvent to form a first spinning solution, the phase change microcapsules are uniformly dispersed in the remaining 50wt% of the spinning solvent to form a second spinning solution, and then the second spinning solution is transferred to the first spinning solution, and then injected into a syringe, and the solution is spun into a porous phase change microcapsule-doped nanofiber layer under preset conditions by electrospinning technology; b) According to the solid-liquid ratio of the organic polymer with radiation cooling performance to the spinning solvent of 1:20 to 3:8 g / mL, the organic polymer with radiation cooling performance is dissolved in the spinning solvent to form a spinning solution, which is then injected into a syringe, and the solution is spun onto the surface of the porous phase change microcapsule-doped nanofiber membrane using electrospinning technology to form a micro-nano fiber membrane, which is vacuum dried at 30 to 80°C for 4 to 28 hours to obtain a flexible cooling fiber fabric doped with phase change microcapsules.

5. The method for preparing the flexible cooling fiber fabric according to claim 4, characterized in that: In step a), the phase change microcapsules are core-shell materials, wherein the shell material comprises one or more combinations of polyurethane, polymethyl methacrylate, silicon dioxide, and ferrosoferric oxide; The core material includes one or more combinations of aliphatic hydrocarbons, fatty acids and fatty alcohols, and the content thereof is not less than 20 wt %.

6. The method for preparing the flexible cooling fiber fabric according to claim 4, characterized in that: In step a), the organic polymer includes one or more combinations of polyvinyl alcohol, polyvinyl butyral resin, and polyvinyl pyrrolidone.

7. The method for preparing the flexible cooling fiber fabric according to claim 4, characterized in that: In step a), the spinning solvent includes one or more combinations of methanol, ethanol, N,N-dimethylformamide and acetone.

8. The method for preparing the flexible cooling fiber fabric according to claim 4, characterized in that: In step a), the solution is spun into a porous phase-change microcapsule-doped nanofiber layer under preset conditions by electrospinning technology, and the conditions include: the electrospinning voltage is 8 to 25 kV, the propulsion speed is 0.005 to 0.1 mm / s, the distance is 5 to 16 cm, and the syringe needle is 17 to 22 gauge.

9. The method for preparing the flexible cooling fiber fabric according to claim 4, characterized in that: In step b), the organic polymer having radiation cooling performance includes one or more combinations of polyvinylidene fluoride hexafluoropropylene, polyvinylidene fluoride, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral resin, polymethyl methacrylate, and polyethylene terephthalate.

10. The method for preparing the flexible cooling fiber fabric according to claim 4, characterized in that: In step b), the spinning solvent includes one or more combinations of N,N-dimethylformamide, N,N-diethylformamide, acetone, ethanol, and tetrahydrofuran.

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