Daytime radiation cooling mask

Abstract

The invention discloses a daytime radiation cooling mask. The design of the mask aims at providing excellent filtering performance and wearing comfort in a high-temperature environment. The mask comprises a breathable filter screen layer and a core filter layer. The core filter layer comprises a PVDF-HFP (Polyvinylidene Fluoride-Hexafluoropropylene) / CA (Carbonic Acid) bi-component spiral nanofiber membrane The core filter layer is collected on the breathable filter screen layer. The core filter layer is prepared by an electrostatic-gas jet spinning method and is composed of poly (vinylidene fluoride-co-hexafluoropropylene) and cellulose acetate, and a unique spiral nanofiber structure is formed, so that the filter efficiency is enhanced, and the radiation cooling effect is achieved. In addition, the mask further comprises a non-woven fabric supporting layer, a nose bridge strip and mask belts, so that the face fitting and the wearing stability are ensured. The mask provided by the invention not only has excellent filtering performance, but also can provide a cooling effect in a hot environment, so that the wearing comfort is remarkably improved, and the mask is innovative personal protection equipment.

Description

Technical Field

[0001] The invention relates to the technical field of personal protective equipment, in particular to a daytime radiation cooling mask. Background Art

[0002] In the field of personal protective equipment, especially in the development of mask technology, as public health and safety issues are increasingly concerned, the demand for masks with efficient filtering functions and comfortable wearing experience is growing. However, although masks in the prior art can provide basic filtering effects, when worn in high temperature environments, the thermal comfort of the wearer is often ignored, resulting in masks easily causing discomfort such as stuffiness and humidity under hot conditions. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a daytime radiation cooling mask. Based on poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and cellulose acetate (CA) materials, PVDF-HFP / CA two-component spiral nanofibers prepared by electrospinning technology are used as the core filter layer to achieve filtering and radiation cooling effects. The present invention not only improves the filtering performance through a carefully designed spiral structure, but also achieves an excellent radiation cooling effect through its special structural characteristics. In a high temperature environment, the nanofibers with a spiral structure can effectively increase air circulation and promote heat dissipation, thereby reducing the temperature of the wearer's face and significantly improving wearing comfort.

[0004] The mask of the present invention solves the comfort problem of traditional masks when used in hot environments by integrating advanced electrospinning technology and innovative spiral nanofiber structure, ensuring that while providing efficient protection functions, it can still maintain a relatively comfortable wearing experience. It is particularly suitable for high temperature and long-term wearing occasions, and is a highly innovative personal protective equipment.

[0005] The present invention is achieved through the following technical solutions:

[0006] The purpose of the present invention is to provide a daytime radiation cooling mask, comprising a breathable filter layer and a core filter layer; the core filter layer comprises a PVDF-HFP / CA two-component spiral nanofiber membrane; the core filter layer is collected on the breathable filter layer.

[0007] In one embodiment of the present invention, the PVDF-HFP / CA two-component spiral nanofiber membrane is prepared by the following method:

[0008] (1) preparing a poly(vinylidene fluoride-co-hexafluoropropylene) solution and a cellulose acetate solution respectively;

[0009] (2) Using the poly(vinylidene fluoride-co-hexafluoropropylene) solution obtained in step (1) and the cellulose acetate solution as spinning solutions, a PVDF-HFP / CA two-component spiral nanofiber membrane is prepared by an air-jet electrospinning process.

[0010] Specifically, the prepared spinning solution is connected to the spinning environment, and a three-channel coaxial needle is used. The CA solution is passed into the innermost layer, the PVDF-HFP solution is passed into the middle layer, and the outermost layer is used as the air flow channel. The positive electrode of the high-voltage power supply is connected to the outermost layer of the needle; a breathable filter is covered on the fiber collector; and the high-voltage power supply, compressed air pump, propulsion pump and collector are turned on.

[0011] In one embodiment of the present invention, in step (1), the mass percentage of poly(vinylidene fluoride-co-hexafluoropropylene) in the poly(vinylidene fluoride-co-hexafluoropropylene) solution is 12wt%-18wt%;

[0012] And / or, the solvent of the poly(vinylidene fluoride-co-hexafluoropropylene) solution is selected from N,N-dimethylformamide and / or N,N-dimethylacetamide, preferably N,N-dimethylformamide.

[0013] In one embodiment of the present invention, the mass percentage of cellulose acetate in the cellulose acetate solution is 12wt%-15wt%;

[0014] And / or, the solvent of the cellulose acetate solution is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide and acetone. The solvent is preferably a mixed solvent of N,N-dimethylformamide and acetone, and the volume ratio of N,N-dimethylformamide to acetone is 0.5:1 to 2:1.

[0015] In one embodiment of the present invention, the cellulose acetate solution further comprises a conductive agent; the conductive agent is selected from one or more of anhydrous lithium chloride, potassium chloride and sodium chloride; the mass percentage of the conductive agent is 1wt%-2wt%, so as to enhance the conductivity of the CA component and improve the interfacial interaction force between the CA component and the PVDF-HFP component.

[0016] In one embodiment of the present invention, in step (2), the air-jet electrospinning process uses a three-channel coaxial needle, and the needle is made of conductive metal; the three-channel coaxial needle includes an inner needle tube, a middle needle tube and an outer needle tube.

[0017] In one embodiment of the present invention, the inner diameter of the inner needle tube is 0.5 mm-0.8 mm;

[0018] And / or, the inner diameter of the intermediate layer needle tube is 1.15 mm-1.6 mm;

[0019] And / or, the inner diameter of the outer needle tube is 1.9mm-2.4mm.

[0020] In one embodiment of the present invention, in step (2), the process parameters of the air-jet electrospinning process are: voltage of 20±5kV; air flow of 0.3±0.1MPa; propulsion speed of the propulsion pump of 0.4±0.2mL / h; the distance between the three-channel coaxial needle and the collector is 15±5cm; the humidity of the spinning environment is controlled at 60±20%; the temperature is controlled at 25±3°C; the rotation speed of the fiber collector is 100±20 revolutions per minute.

[0021] In one embodiment of the present invention, the spinning process uses a three-channel coaxial needle, and the material used for the needle needs to be a conductive metal to cooperate with the airflow to provide sufficient disturbance force for the fiber during the spinning process, thereby improving the production efficiency of the spiral nanofibers.

[0022] In one embodiment of the present invention, during the spinning process, due to the dynamic changes in ambient temperature and humidity, the spun fibers need to be intercepted by a glass slide, and the state and quantity of the spiral fibers need to be observed under a microscope. Based on the real-time monitoring results, parameters such as airflow pressure, voltage, propulsion speed and spinning distance can be flexibly adjusted to ensure the formation quality and consistency of the spiral fibers.

[0023] In one embodiment of the present invention, the daytime radiation cooling mask also includes a non-woven fabric support layer, a nose bridge strip and a mask strap.

[0024] In one embodiment of the present invention, the non-woven fabric support layer is composed of one or more of polypropylene fibers, polyester fibers, polyacrylonitrile fibers and polyamide fibers.

[0025] In one embodiment of the present invention, the breathable filter is composed of absorbent cotton which has the advantages of being comfortable and breathable, soft and skin-friendly, and resistant to tearing, and serves as a carrier of the spiral fiber membrane;

[0026] The structural design of the daytime radiation cooling mask provided by the present invention is as follows:

[0027] The daytime radiation cooling mask adopts a multi-layer composite structure, including inner and outer protective support layers and a core filter layer in the middle. The core filter layer is composed of spiral nanofibers loaded on a breathable filter, and the outer and inner layers are made of breathable and comfortable polypropylene (PP) non-woven fabrics to ensure the breathability and comfort of the wearer in a high temperature environment.

[0028] The innovation of the present invention lies in the use of PVDF-HFP and CA two-component spiral nanofibers prepared by electrostatic air spraying, and the unique spiral structure design achieves efficient radiation cooling effect. The present invention combines microfluidic electrospinning with air-jet spinning technology, and uses a three-channel coaxial needle to prepare two-component spiral nanofibers. PVDF-HFP is used as an elastic component and CA is used as a plastic component. During the electrostatic air spraying process, the spinning solution of PVDF-HFP and CA is subjected to the combined action of electric field force and airflow, and due to the difference in elastic modulus of the two materials, asynchronous strain is generated during the spinning process, thereby forming a spiral structure.

[0029] The spiral nanofibers in the core filter layer of the present invention are made of PVDF-HFP and CA materials, both of which have high mid-infrared emissivity and can effectively enhance the passive radiation cooling ability during the day; the spiral structure of the core filter layer further improves the scattering efficiency of sunlight, which can not only significantly reflect sunlight, but also radiate the heat of the wearer's body surface to outer space through the atmospheric window, thereby achieving efficient radiation cooling effect; the multi-layer structure design comprehensively considers functionality and comfort, and provides the wearer with a good wearing experience through the softness and breathability of PP non-woven fabric, which can maintain comfort even in high temperature environments. Through the above design, the present invention has excellent cooling effect, comfort and mask filtering protection performance, and provides a new solution for protection and heat dissipation under high temperature conditions during the day.

[0030] The daytime radiation cooling mask provided by the present invention is significantly innovative in both structural design and material selection, and its beneficial effects are specifically reflected in the following aspects:

[0031] 1. Excellent filtering effect: The special structure of the spiral nanofiber membrane not only improves the filtering efficiency of the filter layer, but also effectively blocks tiny particles and harmful gases;

[0032] 2. Daytime radiation cooling performance: PVDF-HFP and CA materials with high and medium infrared emissivity are used, and the solar scattering ability of the core filter layer is greatly improved through the optimized design of the spiral nanofiber structure. Through the solar scattering and radiation cooling mechanism, the effective reflection of sunlight and the efficient discharge of human body heat are achieved, which significantly reduces the wearer's facial temperature in a high temperature environment.

[0033] 3. Comfortable wearing experience: The inner and outer layers are made of PP non-woven fabric with excellent air permeability, ensuring soft touch and good air permeability during wearing. Through reasonable layered structure design, it can still remain refreshing and comfortable even when worn for a long time in a high temperature environment;

[0034] 4. Strong process controllability: The preparation method of the present invention prepares spiral nanofiber membranes through electrostatic air jet spinning technology, and can ensure the stability and consistency of fiber quality by real-time monitoring and dynamic adjustment of parameters (such as airflow, voltage, spinning distance, etc.). The preparation process can be industrialized and promoted, suitable for large-scale production, and has good economic and application prospects;

[0035] 5. Potential application prospects: This mask is particularly suitable for high temperature and strong light environments, such as outdoor work in summer, desert areas, tropical areas and other scenes. It can provide users with a full range of protection and cooling solutions. It is also suitable for protection needs in daily life and can meet the usage scenarios of different groups of people.

[0036] In summary, the present invention integrates cooling, protection and comfort through innovations in materials, structures and processes, providing an efficient and practical solution for individual protection in high temperature environments, and has significant social benefits and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0038] Figure 1 This is a schematic diagram of the front structure of the daytime radiation cooling mask in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the reverse structure of the daytime radiation cooling mask in an embodiment of the present invention;

[0040] Figure 3 2. It is a schematic diagram of the cross-sectional structure of the mask body;

[0041] Figure 4 is the filtration efficiency measured in the test case;

[0042] Figure 5 is the filtration resistance measured in the test case;

[0043] Figure 6 is the reflectivity of the sunlight band measured in the test example;

[0044] Description of the accompanying drawings in the specification: mask body 1, mask rope 2, nose bridge strip 3, inner non-woven fabric layer 1-1, breathable filter layer 1-2, core filter layer 1-3, outer non-woven fabric layer 1-4. DETAILED DESCRIPTION

[0045] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0046] The present invention will be further described below in conjunction with the accompanying drawings:

[0047] The present invention provides a daytime radiation cooling mask, comprising a mask body (1), wherein a mask strap (2) is provided on the mask body (1), and comprises, from inside to outside, an inner polypropylene non-woven fabric support layer (1-1), a breathable filter layer (1-2), a core filter layer (1-3) and an outer polypropylene non-woven fabric support layer (1-4); and a nose bridge strip (3) is provided on the upper side of the mask facing the face.

[0048] The preparation method of the daytime radiation cooling mask of the present invention comprises the following steps:

[0049] (1) Preparation of a breathable filter layer and a core filter layer: First, dissolve poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) particles in an N,N-dimethylformamide (DMF) solution to obtain a PVDF-HFP solution. Secondly, dissolve cellulose acetate particles in an N,N-dimethylformamide / acetone (DMAC / AC) mixed solvent, add anhydrous lithium chloride and mix evenly to increase the conductivity of the solution to obtain a CA solution. Using the PVDF-HFP solution and the CA solution as spinning solutions, a PVDF-HFP / CA two-component spiral nanofiber membrane is prepared by an air-jet electrospinning process, and the spiral nanofibers are collected on a breathable filter. After completion, remove it together with the breathable filter to obtain the breathable filter and core filter layer of the present invention, and cut them to the corresponding size according to the drawing;

[0050] (2) Preparation of inner support layer: Cut the PP nonwoven fabric to the corresponding size according to the drawing;

[0051] (3) Preparation of outer supporting layer: same as step (2);

[0052] (4) Preparation of a daytime radiation cooling mask: The inner support layer, breathable filter layer, core filter layer and outer support layer prepared above are stacked in sequence from bottom to top, and a nose bridge strip and a mask strap are placed at the top of the inner support layer and the upper and lower bottom corners of the left and right sides, respectively, and packaged using a hot pressing process to obtain a daytime radiation cooling mask.

[0053] In the present invention, unless otherwise specified, the material of the support layers (1-1) and (1-4) is polypropylene, which has the advantages of being moisture-proof, breathable, flexible, lightweight, non-toxic and non-irritating.

[0054] In the present invention, unless otherwise specified, the core filter layer (1-3) is prepared from poly(vinylidene fluoride-co-hexafluoropropylene) and cellulose acetate by a multi-channel needle electrostatic air-jet spinning method to form a fiber with a spiral structure to improve the filtering efficiency and radiation cooling effect of the mask.

[0055] In the present invention, unless otherwise specified, the core filter layer (1-3) is prepared by a three-channel coaxial needle using an electrostatic air spray method. The electrostatic force is mainly responsible for the formation of spiral fibers. However, nanoscale fibers will entangle and adhere to each other in the spinning environment and cannot be collected in the form of fiber membranes. Therefore, air flow force is introduced to assist the collection of spiral fibers.

[0056] In the present invention, unless otherwise specified, the proportion of PVDF-HFP in the PVDF-HFP solution is 12wt%-18wt%. The proportion of CA in the CA solution is 12wt%-15wt%, and the ratio of DMAC to AC in the mixed solvent is 0.5-2. At the same time, 1wt%-2wt% of anhydrous lithium chloride needs to be added to the CA solution to enhance the conductivity of the CA component and improve the interfacial force between the CA component and the PVDF-HFP component; that is, it plays a role in enhancing the plasticity of the CA component and improving the interfacial bonding force between CA and PVDF-HFP.

[0057] In the present invention, unless otherwise specified, in step (1), the three-channel coaxial needle used has an inner needle tube inner diameter of 0.5 mm-0.8 mm, a middle needle tube inner diameter of 1.15 mm-1.6 mm, and an outer needle tube inner diameter of 1.9 mm-2.4 mm.

[0058] In the present invention, unless otherwise specified, the spinning process uses a three-channel coaxial needle, and the material used in the needle must be a conductive metal to cooperate with the airflow to provide sufficient disturbance force for the fiber during the spinning process, thereby improving the production efficiency of the spiral nanofibers.

[0059] In the present invention, unless otherwise specified, the process parameters of electrostatic air jet spinning in step (1) are: voltage is 20±5kV; required air flow is 0.3±0.1MPa; propulsion speed is 0.4±0.2ml / h; collector distance is 15±5cm; the humidity of the spinning environment is controlled at 60±20%, and the temperature is controlled at 25±3°C; the rotation speed of the fiber collector is 100±20 revolutions per minute.

[0060] In the present invention, unless otherwise specified, the breathable filter (1-2) used in step (1) is composed of absorbent cotton having the advantages of being comfortable and breathable, soft and skin-friendly, and tear-resistant, and serves as a carrier of the spiral fiber membrane; that is, the breathable gauze is loaded on the collector to bear the role of loading the spiral nanofibers.

[0061] In the present invention, unless otherwise specified, in steps (2) and (3), the non-woven fabric layers (1-1) and (1-4) are composed of polypropylene fibers having the advantages of moisture-proof, breathable, flexible, lightweight, non-toxic and non-irritating, and serve as a support and protection for the core filter layer.

[0062] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0063] Example 1

[0064] This embodiment provides a method for preparing a daytime radiation cooling mask, which specifically includes the following steps:

[0065] (1) Preparation of air permeable filter layer and core filter layer

[0066] First, PVDF-HFP particles were dissolved in DMF solvent and stirred evenly to obtain a 15wt% PVDF-HFP spinning solution. At the same time, CA particles were dissolved in a mixed solvent of DMAC and AC with a volume ratio of 1:1, and 1.8wt% anhydrous lithium chloride was added to the CA spinning solution, fully mixed to ensure that the solution was uniform, and a 15wt% CA spinning solution was obtained; the addition of anhydrous lithium chloride was to improve the conductivity and fiber interface bonding performance.

[0067] Lay a breathable filter made of absorbent cotton on the surface of the fiber collector as a base carrier. Load the prepared PVDF-HFP solution and CA solution into different channels of the three-channel coaxial needle respectively, and connect them to the electrospinning device through the syringe pump combination. Start the equipment, including the power supply, propulsion pump, air pump, transformer and fiber collector, and set the spinning environment parameters as follows:

[0068] Ambient temperature: 22℃;

[0069] Humidity: 65%;

[0070] Voltage: 20kV;

[0071] Air pressure: 28MPa;

[0072] Advance speed: 0.2mL / h;

[0073] Collector speed: 100 revolutions per minute;

[0074] Spinning time: 60min.

[0075] During the spinning process, the fiber samples cut from the slide are observed under a microscope to dynamically monitor the formation state and quantity of the spiral fibers. The voltage, air pressure, spinning distance, propulsion speed and other parameters are adjusted in a timely manner according to the monitoring results to ensure the uniformity of the fiber structure and the stability of quality. After the spinning is completed, the air filter and the loaded spiral nanofiber membrane are removed from the collector and cut into the required size according to the design drawings to obtain a composite of the air filter layer and the core filter layer.

[0076] (2) Preparation of inner support layer

[0077] Choose soft, breathable and moisture-proof PP non-woven material, cut it to specifications matching the size of the mask according to the design drawings, and set it aside.

[0078] (3) Preparation of outer support layer

[0079] Same as step (2), select PP non-woven fabric and cut it to the corresponding size for the outer supporting protective layer of the mask.

[0080] (4) Preparation of daytime radiation cooling mask

[0081] The breathable filter and core filter layer complex prepared in step (1), and the inner support layer and outer support layer prepared in steps (2) and (3) are stacked from bottom to top. During the stacking process, the bridge of the nose is embedded at the top of the inner support layer, and the mask straps are fixed at the upper and lower corners on the left and right sides. Finally, all components are encapsulated by a hot pressing process to ensure the close combination of the layers and the stability of the overall structure, and the preparation of the daytime radiation cooling mask is completed.

[0082] Example 2

[0083] This embodiment provides a method for preparing a daytime radiation cooling mask, which is basically the same as that of Embodiment 1, except that:

[0084] In step (1), the spinning time is 40 minutes.

[0085] Comparative Example 1

[0086] This comparative example provides a method for preparing a daytime radiation cooling mask, which is basically the same as Example 1, except that:

[0087] In step (1), the spinning voltage is 10 kV.

[0088] Comparative Example 2

[0089] This comparative example provides a method for preparing a daytime radiation cooling mask, which is basically the same as Example 1, except that:

[0090] In step (1), the CA component is eliminated, and only PVDF-HFP is involved in the preparation of the core filter layer.

[0091] Test example:

[0092] In order to verify the comprehensive performance of the daytime radiation cooling mask of the present invention, the materials prepared in Example 1, Example 2 and Comparative Example 1 and Comparative Example 2 were tested for filtration efficiency, filtration resistance and solar light band reflectivity, and the specific methods are as follows:

[0093] (1) Filtration efficiency and filtration resistance test

[0094] Test instrument: TSI 8130A automatic filter material tester is used for testing;

[0095] Test conditions:

[0096] Test flow rate: 32L / min;

[0097] Test area: 100cm 2 ;

[0098] Sampling time: 30s;

[0099] Test method: Place each material in the test instrument separately, and record the filtration efficiency (%) and filtration resistance (Pa) according to the set conditions.

[0100] (2) Solar band reflectivity test

[0101] Test instrument: UV3600 ultraviolet-visible-near infrared spectrophotometer is used for testing;

[0102] Test benchmark: Use barium sulfate plate as reference sample to ensure the accuracy of the test;

[0103] Test band: Test the reflectivity changes of the test material in the band from 200nm to 2500nm, focusing on the reflection effect of the main band of sunlight from 400nm to 1100nm;

[0104] Test method: Fix the sample on the instrument sample stage, adjust the light source and detector to the optimal state, scan to obtain the reflectivity curve, and calculate the average reflectivity to evaluate the cooling ability of the sample.

[0105] Figure 4 Shown is the filtration efficiency measured in the test case;

[0106] Figure 5 Shown is the filtration resistance measured in the test case;

[0107] Figure 6 Shown is the reflectivity in the sunlight band measured in the test example.

[0108] from Figure 4-6It can be seen that in Comparative Example 1, since the spinning voltage is significantly lower than that in Example 1 and Example 2, the disturbance force of the spinning solution jet in the spinning environment is weakened, resulting in a significant reduction in the output of spiral fibers, thereby making the microstructure inside the fiber membrane incomplete, greatly weakening the multiple diffuse reflections of sunlight inside the fiber membrane, and reducing the sunlight reflectivity of the fiber membrane. At the same time, since some of the spinning solutions failed to form spiral fibers, these droplets adhered to the surface of the fiber membrane under the action of the airflow, which not only destroyed the uniformity of the fiber membrane, but also significantly increased the filtration resistance, directly affecting the breathing comfort of the mask. In Comparative Example 2, the CA component was cancelled, and only the PVDF-HFP straight fiber membrane was relied on to achieve radiation cooling and filtering functions. However, due to the lack of structural design on the microscale of the PVDF-HFP fiber membrane, its sunlight reflectivity can only rely on the intrinsic properties of the material, and a limited reflection effect is achieved through the functional groups in the molecular structure, which is significantly different from the enhancement effect brought by the spiral structure in Example 1 and Example 2. In addition, although the dense structure of the PVDF-HFP straight fiber membrane ensures a high filtration efficiency, it also leads to a significant increase in filtration resistance, which is much higher than that of Example 1 and Example 2. This shows that the intrinsic performance of a single material is not enough to achieve a balance between filtration performance and filtration resistance. The embodiment of the present invention successfully prepared a high-yield and uniformly distributed spiral nanofiber membrane by optimizing the spinning parameters. The spiral structure significantly enhances the fiber membrane's ability to scatter sunlight multiple times, further improving the radiation cooling performance, while maintaining a moderate porosity and uniformity, achieving a balance between high filtration efficiency and low filtration resistance. The present invention not only far exceeds the comparative sample in cooling effect, but also shows excellent comprehensive advantages in filtration performance and wearing comfort, fully reflecting its technical value and application prospects in the field of high temperature protection.

[0109] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A daytime radiation cooling mask, characterized in that: It comprises a breathable filter layer and a core filter layer; the core filter layer comprises a PVDF-HFP / CA two-component spiral nanofiber membrane; and the core filter layer is collected on the breathable filter layer.

2. The daytime radiation cooling mask according to claim 1, characterized in that: The PVDF-HFP / CA two-component spiral nanofiber membrane is prepared by the following method: (1) preparing a poly(vinylidene fluoride-co-hexafluoropropylene) solution and a cellulose acetate solution respectively; (2) Using the poly(vinylidene fluoride-co-hexafluoropropylene) solution obtained in step (1) and the cellulose acetate solution as spinning solutions, a PVDF-HFP / CA two-component spiral nanofiber membrane is prepared by an air-jet electrospinning process.

3. The daytime radiation cooling mask according to claim 2, characterized in that: In step (1), the mass percentage of poly(vinylidene fluoride-co-hexafluoropropylene) in the poly(vinylidene fluoride-co-hexafluoropropylene) solution is 12wt%-18wt%; And / or, the solvent of the poly(vinylidene fluoride-co-hexafluoropropylene) solution is selected from N,N-dimethylformamide and / or N,N-dimethylacetamide.

4. The daytime radiation cooling mask according to claim 2, characterized in that: The mass percentage of cellulose acetate in the cellulose acetate solution is 12wt%-15wt%; And / or, the solvent of the cellulose acetate solution is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide and acetone.

5. The daytime radiation cooling mask according to claim 2, characterized in that: The cellulose acetate solution further comprises a conductive agent; the conductive agent is selected from one or more of anhydrous lithium chloride, potassium chloride and sodium chloride.

6. The daytime radiation cooling mask according to claim 2, characterized in that: In step (2), the air-jet electrospinning process uses a three-channel coaxial needle, and the needle is made of conductive metal; the three-channel coaxial needle includes an inner needle tube, a middle needle tube and an outer needle tube.

7. The daytime radiation cooling mask according to claim 6, characterized in that: The inner diameter of the inner needle tube is 0.5mm-0.8mm; And / or, the inner diameter of the intermediate layer needle tube is 1.15 mm-1.6 mm; And / or, the inner diameter of the outer needle tube is 1.9mm-2.4mm.

8. The daytime radiation cooling mask according to claim 2, characterized in that: In step (2), the process parameters of the air-jet electrospinning process are: voltage of 20±5kV; airflow of 0.3±0.1MPa; propulsion speed of 0.4±0.2mL / h; collector distance of 15±5cm; humidity of the spinning environment is controlled at 60±20%; temperature is controlled at 25±3°C; and the rotation speed of the fiber collector is 100±20 revolutions per minute.

9. The daytime radiation cooling mask according to claim 1, characterized in that: The daytime radiation cooling mask also includes a non-woven fabric support layer, a nose bridge strip and a mask strap.

10. The daytime radiation cooling mask according to claim 9, characterized in that: The nonwoven fabric support layer is composed of one or more of polypropylene fibers, polyester fibers, polyacrylonitrile fibers and polyamide fibers.

Images