Radiative cooling finishing agent, radiative cooling fiber membrane, preparation method and application thereof

Abstract

The present invention relates to a radiative cooling finishing agent, a radiative cooling fiber membrane, and a preparation method and application thereof. The radiative cooling finishing agent comprises radiative cooling particles, a binder, a dispersant, and water. At 25°C, the viscosity of the radiative cooling finishing agent is 10 CPS - 300 CPS. Among them, the solar reflectance of the radiative cooling particles in the 0.3 μm - 2.5 μm band is greater than or equal to 70%, and the emissivity in the 8 μm - 13 μm atmospheric window band is greater than or equal to 80%. The radiative cooling fiber membrane prepared by using this radiative cooling finishing agent has excellent full-band solar protection and zero-energy passive cooling effects. At the same time, it has excellent mechanical properties, and the radiative cooling particles in the radiative cooling fiber membrane are not easy to fall off, which not only avoids environmental pollution but also extends the service life of the radiative cooling fiber membrane.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and particularly to a radiative cooling finishing agent, a radiative cooling fiber film, and a preparation method and application thereof. Background Art

[0002] The radiative cooling fiber film can achieve the purpose of cooling without consuming energy and can be used to prepare various textiles with cooling requirements. There are mainly two traditional preparation methods for radiative cooling fiber films. One is to add radiative cooling particles to the electrospinning solution. However, this preparation method will lead to a decrease in the mechanical properties of the fiber film. The other method is to form radiative cooling particles on the outer surface of the fiber film to form a radiative cooling particle layer. However, it is difficult to obtain a uniform radiative cooling particle layer by this preparation method, and the radiative cooling particles are prone to fall off, which will not only reduce the radiative cooling effect but also cause environmental pollution. Summary of the Invention

[0003] Based on this, in view of the above problems, it is necessary to provide a radiative cooling finishing agent, a radiative cooling fiber film, and a preparation method and application thereof. The radiative cooling fiber film has excellent full-band sunlight protection and zero-energy passive cooling effects, excellent mechanical properties, and the radiative cooling particles on the radiative cooling fiber film are not prone to fall off, which not only avoids environmental pollution but also extends the service life of the radiative cooling fiber film.

[0004] The present invention provides a radiative cooling finishing agent, which includes radiative cooling particles, a binder, a dispersant, and water. At 25°C, the viscosity of the radiative cooling finishing agent is 10 CPS - 300 CPS. Among them, the solar reflectance of the radiative cooling particles in the 0.3 μm - 2.5 μm band is greater than or equal to 70%, and the emissivity in the 8 μm - 13 μm atmospheric window is greater than or equal to 80%.

[0005] In one embodiment, the particle size of the radiative cooling particles is 2 nm - 1000 nm.

[0006] In one embodiment, the mass fraction of the radiative cooling particles in the radiative cooling finishing agent is 0.1% - 50%.

[0007] In one embodiment, the radiative cooling particles include at least one of titanium dioxide, silicon dioxide, barium sulfate, pearlescent powder, heavy calcium powder, alumina, zinc oxide, zirconia, cerium oxide, lanthanum oxide, talc powder, zinc sulfide, ceramic powder, or magnesium oxide.

[0008] In one embodiment, the mass ratio of the radiative cooling particles to the binder is 1:5 - 2.5:1.

[0009] In one embodiment, the binder includes at least one of polyurethane, aqueous polyacrylic acid, polyethylene oxide, polyvinyl alcohol or polyethylene glycol;

[0010] And / or, the dispersant includes at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecyl carboxylate or cetyltrimethylammonium bromide, and the mass fraction of the dispersant in the radiative cooling finishing agent is less than or equal to 2%.

[0011] A radiative cooling fiber film, which includes a fiber film and a radiative cooling coating provided on the surface of the fibers in the fiber film. Among them, the radiative cooling coating is formed after drying the above-mentioned radiative cooling finishing agent.

[0012] In one embodiment, the material of the fiber film includes at least one of polyacrylonitrile, polyvinyl alcohol, polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinylpyrrolidone, nylon 4,6, nylon 6 or polyimide.

[0013] A method for preparing a radiative cooling fiber film includes the following steps

[0014] Providing a fiber film; and

[0015] Using the padding method to form the above-mentioned radiative cooling finishing agent on the fiber film, and drying to obtain a radiative cooling fiber film.

[0016] A textile, which is made of the above-mentioned radiative cooling fiber film.

[0017] Since the viscosity of the radiative cooling finishing agent at 25°C is 10 CPS - 300 CPS, when using the radiative cooling finishing agent of the present invention to prepare a radiative cooling fiber film, the surface tension and internal friction in the radiative cooling finishing agent are both smaller than the van der Waals force of the binder on the surface of the fibers in the fiber film, so that the binder can be uniformly formed on the fiber surface. Thus, the radiative cooling particles can be uniformly formed on the fiber surface by the action of the binder, and a radiative cooling coating with a uniform thickness is obtained. Therefore, the mechanical properties of the radiative cooling fiber film of the present invention will not be affected by the radiative cooling particles, and the radiative cooling particles in the radiative cooling fiber film are not easily detached, which can extend the service life of the radiative cooling fiber film and enable the radiative cooling fiber film to be better applied to the weaving of various fabrics.

[0018] Meanwhile, since the solar reflectivity of the radiative cooling particles in the 0.3μm - 2.5μm band is greater than or equal to 70%, and the emissivity in the 8μm - 13μm atmospheric window is greater than or equal to 80%, therefore, the solar transmittance of the radiative cooling fiber film of the present invention in the 0.3μm - 0.4μm band is less than or equal to 1%, the solar transmittance in the 0.3μm - 2.5μm band is less than or equal to 12%, and the emissivity in the 8μm - 13μm atmospheric window is greater than or equal to 85%, having excellent full-band solar protection and zero-energy passive cooling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the preparation method of the radiative cooling fiber film provided by the present invention. In the figure, 10 represents the radiative cooling finishing agent, and 20 represents the fiber film;

[0020] Figure 2 It is a scanning electron microscope image of the polyacrylonitrile fiber film obtained in Comparative Example 1 and the radiative cooling fiber films obtained in Examples 1 - 5. In the figure, A represents the scanning electron microscope image of the polyacrylonitrile fiber film in Comparative Example 1, B represents the scanning electron microscope image of the radiative cooling fiber film in Example 1, C represents the scanning electron microscope image of the radiative cooling fiber film in Example 2, D represents the scanning electron microscope image of the radiative cooling fiber film in Example 3, E represents the scanning electron microscope image of the radiative cooling fiber film in Example 4, and F represents the scanning electron microscope image of the radiative cooling fiber film in Example 5;

[0021] Figure 3 It is a transmission electron microscope image of the fibers of the radiative cooling fiber film obtained in Example 3 at different magnifications. DETAILED DESCRIPTION OF THE INVENTION

[0022] The radiative cooling finishing agent, radiative cooling fiber film, and their preparation methods and applications provided by the present invention will be further described below.

[0023] The radiative cooling finishing agent provided by the present invention is mainly used for padding the fiber film, thereby coaxially forming a radiative cooling coating on the surface of the fibers in the fiber film, and thus obtaining the radiative cooling fiber film.

[0024] The radiative cooling finishing agent provided by the present invention includes radiative cooling particles, a binder, a dispersant, and water. At 25°C, the viscosity of the radiative cooling finishing agent is 10CPS - 300CPS.

[0025] Among them, in order to enable the radiative cooling finishing agent to form a uniform radiative cooling coating on the surface of the fibers of the fiber film, the binder includes at least one of polyurethane, waterborne polyacrylate, polyethylene oxide, polyvinyl alcohol, or polyethylene glycol.

[0026] In one embodiment, the radiative cooling particles include at least one of titanium dioxide, silicon dioxide, barium sulfate, pearlescent powder, heavy calcium powder, alumina, zinc oxide, zirconium oxide, cerium oxide, lanthanum oxide, talc powder, zinc sulfide, ceramic powder, or magnesium oxide. The shape of the radiative cooling particles is not limited and can be spherical, ellipsoidal, or other geometric shapes, preferably spherical or ellipsoidal, with a particle size of 2 nm - 1000 nm, more preferably 5 nm - 500 nm, and even more preferably 10 nm - 100 nm.

[0027] In order to enable the radiative cooling particles to be more uniformly and stably dispersed in the radiative cooling finishing agent, the mass fraction of the radiative cooling particles in the radiative cooling finishing agent is 0.1% - 50%, more preferably 1% - 40%, and even more preferably 2% - 20%; the mass ratio of the radiative cooling particles to the binder is 1:40 - 5:1, more preferably 1:5 - 2.5:1.

[0028] On the one hand, the dispersant can make the radiative cooling particles more uniformly dispersed in the radiative cooling finishing agent and prevent the radiative cooling particles from settling. On the other hand, it can assist in regulating the viscosity of the radiative cooling finishing agent. In one embodiment, the dispersant includes at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecylcarboxylate, or cetyltrimethylammonium bromide, and the mass fraction of the dispersant in the radiative cooling finishing agent is less than or equal to 2%, more preferably 1% - 2%.

[0029] It should be noted that the present invention can combine one or more of the conditions such as the selection of the binder type, the control of the binder dosage, the selection of the dispersant type, the control of the dispersant dosage, or the control of the dosage of the radiative cooling particles, so that the viscosity of the radiative cooling finishing agent at 25°C is maintained within the range of 10 CPS - 300 CPS. Preferably, the viscosity of the radiative cooling finishing agent at 25°C is maintained at 100 CPS - 280 CPS.

[0030] Since at 25°C, the viscosity of the radiative cooling finishing agent is 10 CPS - 300 CPS, when using the radiative cooling finishing agent of the present invention to prepare the radiative cooling fiber membrane, the surface tension and internal friction in the radiative cooling finishing agent are both smaller than the van der Waals force on the fiber surface in the fiber membrane of the binder. This enables the binder to be uniformly formed on the fiber surface during the padding process. Thus, during the drying process, the binder dries into a film and uniformly fixes the radiative cooling particles on the fiber surface, obtaining a radiative cooling coating with a uniform thickness.

[0031] Therefore, the mechanical properties of the radiative cooling fiber membrane will not be affected by the radiative cooling particles, and the radiative cooling particles in the radiative cooling fiber membrane are not easily detached, which can extend the service life of the radiative cooling fiber membrane and enable the radiative cooling fiber membrane to be better applied to the weaving of various fabrics.

[0032] In addition, since the solar reflectivity of the radiation cooling particles in the 0.3μm-2.5μm band is greater than or equal to 70%, and the atmospheric window emissivity in the 8μm-13μm band is greater than or equal to 80%, the solar transmittance of the radiation cooling fiber membrane in the 0.3μm-0.4μm band is less than or equal to 1%, the solar transmittance in the 0.3μm-2.5μm band is less than or equal to 12%, and the atmospheric window emissivity in the 8μm-13μm band is greater than or equal to 85%, which has excellent full-band solar protection and zero-energy passive cooling effects.

[0033] It should be noted that the solar transmittance in the 0.3μm-0.4μm band refers to the ratio of the ultraviolet light flux passing through the material to the ultraviolet light flux projected on the surface of the material; the solar transmittance in the 0.3μm-2.5μm band refers to the ratio of the solar light flux passing through the material to the solar light flux projected on the surface of the material.

[0034] like Figure 1 FIG. 1 is a schematic diagram of a method for preparing a radiation cooling fiber membrane provided by the present invention, which specifically includes the following steps:

[0035] S1, providing a fiber membrane 20; and

[0036] S2, forming the above-mentioned radiation cooling finishing agent 10 on the fiber membrane 20 by a padding method, and obtaining a radiation cooling fiber membrane after drying.

[0037] In step S1, the fiber membrane 20 may include at least one of ordinary fibers or nanofibers. Considering that the fiber membrane 20 composed of nanofibers has a higher specific surface area and a higher liquid carrying rate during the immersion process, the fiber membrane 20 is preferably a fiber membrane 20 composed of nanofibers.

[0038] In one embodiment, the fiber membrane 20 composed of nanofibers can be directly obtained by electrostatic spinning. The present invention does not impose any particular limitation on the electrostatic spinning method, and specifically can include the following steps:

[0039] Providing an electrospinning solution, wherein a fiber precursor is dissolved in the electrospinning solution; and

[0040] The electrospinning solution is electrospun, and the substrate is used to receive the nanofibers, and the nanofibers form a fiber membrane 20 .

[0041] It can be understood that the function of the substrate is to receive the nanofibers obtained by electrospinning, and the fiber membrane 20 composed of the nanofibers is further used for impregnation.

[0042] In one embodiment, the solvent for electrospinning includes at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), N-methylpyrrolidone, chloroform, or acetone.

[0043] In one embodiment, the fiber precursor includes at least one of polyacrylonitrile, polyvinyl alcohol, polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinylpyrrolidone, nylon 4,6, nylon 6, or polyimide. The mass fraction of the fiber precursor in the electrospinning solution is 3% - 20%.

[0044] In step S2, since the fiber membrane 20 has a high specific surface area, compared with traditional fabrics, the fiber membrane 20 has more voids and a higher liquid-carrying rate, reaching 40% - 800%, preferably 60% - 600%, and further preferably 80% - 600%. On the one hand, it is beneficial to form a more uniform radiative cooling layer. On the other hand, the applicable fiber membrane 20 is more extensive. For example, a fiber membrane 20 with hydrophobic properties can also form a radiative cooling layer by padding.

[0045] In one embodiment, the padding method is selected from one-padding-one-rolling, two-padding-two-rolling, or multi-padding-multi-rolling, which is adjusted according to the hydrophilicity of the fiber membrane 20 and the liquid-carrying rate of the fiber membrane 20 during padding. When the liquid-carrying rate is less than or equal to 100%, two-padding-two-rolling or multi-padding-multi-rolling can be used. When the liquid-carrying rate is greater than 100%, one-padding-one-rolling can be used.

[0046] During the padding process, the radiative cooling particles can be uniformly formed on the surface of the fibers of the fiber membrane 20 through a binder.

[0047] In one embodiment, in order to enable the radiative cooling particles to be firmly bonded to the surface of the fibers in the fiber membrane 20 through a binder, during the drying step, the temperature is 30°C - 150°C.

[0048] The preparation method of the radiative cooling fiber membrane provided by the present invention realizes the simple preparation of the radiative cooling fiber membrane. The radiative cooling fiber membrane prepared by using the preparation method is environmentally friendly, has a long service life, and has excellent full-band sunlight protection, zero-energy passive cooling effect, and excellent mechanical properties.

[0049] The present invention also provides a radiative cooling fiber membrane, including a fiber membrane 20 and a radiative cooling coating provided on the surface of the fibers in the fiber membrane 20. The radiative cooling coating is formed after drying the above-mentioned radiative cooling finishing agent 10. The radiative cooling fiber membrane can be prepared by the preparation method of the radiative cooling fiber membrane of the present invention.

[0050] In one embodiment, the material of the fiber membrane 20 includes at least one of polyacrylonitrile, polyvinyl alcohol, polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinylpyrrolidone, nylon 4,6, nylon 6 or polyimide.

[0051] For the radiative cooling fiber membrane provided by the present invention, the radiative cooling particles can be uniformly formed on the fiber surface of the fiber membrane 20 by means of the binder. Therefore, the mechanical properties of the radiative cooling fiber membrane are not affected by the radiative cooling particles, and it has excellent mechanical properties. Moreover, the radiative cooling particles in the radiative cooling fiber membrane are not easily detached, which not only avoids environmental pollution, but also extends the service life of the radiative cooling fiber membrane. In addition, the radiative cooling fiber membrane also has excellent sunlight protection and zero-energy passive cooling effects. The sunlight transmittance in the 0.3μm - 0.4μm band is less than or equal to 1%, the sunlight transmittance in the 0.3μm - 2.5μm band is less than or equal to 12%, and the emissivity in the 8μm - 13μm atmospheric window is greater than or equal to 85%.

[0052] Furthermore, when the radiative cooling fiber membrane is used to prepare textiles such as clothes, curtains, tents, parasols, hats, scarves, car covers, and hoods that require cooling, while maintaining the comfort and breathability of the textiles, cooling can be achieved through the textiles, increasing the comfort level without consuming energy, which is energy-saving and environmentally friendly.

[0053] Therefore, the present invention also provides a textile made of the above-mentioned radiative cooling fiber membrane, and the textile has excellent full-band sunlight protection and zero-energy passive cooling effects.

[0054] Hereinafter, the radiative cooling finishing agent, the radiative cooling fiber membrane, and their preparation methods and applications will be further described through the following specific examples.

[0055] Example 1

[0056] Dissolve polyacrylonitrile in water to obtain an electrospinning solution. Among them, the mass fraction of polyacrylonitrile in the electrospinning solution is 6%. Obtain a polyacrylonitrile fiber membrane 20 through electrospinning technology, where the diameter of the polyacrylonitrile fiber is nanoscale.

[0057] Disperse titanium dioxide with a particle size of 50 nm, sodium dodecylbenzenesulfonate dispersant, and waterborne polyacrylic acid binder in water to obtain a radiative cooling finishing agent 10. Among them, at 25 °C, the viscosity of the radiative cooling finishing agent 10 is 60 CPS. The solar reflectivity of titanium dioxide in the 0.3 μm - 2.5 μm band is 87%, and the emissivity in the 8 μm - 13 μm atmospheric window is 80%. The mass fraction of titanium dioxide in the radiative cooling finishing agent 10 is 0.5%, the mass fraction of sodium dodecylbenzenesulfonate dispersant in the radiative cooling finishing agent 10 is 1.4%, and the mass fraction of waterborne polyacrylic acid binder in the radiative cooling finishing agent 10 is 20%.

[0058] Immerse the polyacrylonitrile fiber membrane 20 in the above-mentioned radiative cooling finishing agent 10, and set the above-mentioned radiative cooling finishing agent 10 on the surface of the polyacrylonitrile fiber by the one-dip-one-padding method. After padding, the liquor pickup rate of the polyacrylonitrile fiber membrane 20 is 220%. Dry the padded polyacrylonitrile fiber membrane 20 at 80 °C to form a radiative cooling coating on the fiber surface in the polyacrylonitrile fiber membrane 20, and obtain a radiative cooling fiber membrane.

[0059] Example 2

[0060] Example 2 is carried out with reference to Example 1, the difference is that the mass fraction of titanium dioxide in the radiative cooling finishing agent 10 is 1%, and at 25 °C, the viscosity of the radiative cooling finishing agent 10 is 76 CPS.

[0061] Example 3

[0062] Example 3 is carried out with reference to Example 1, the difference is that the mass fraction of titanium dioxide in the radiative cooling finishing agent 10 is 5%, and at 25 °C, the viscosity of the radiative cooling finishing agent 10 is 100 CPS.

[0063] Example 4

[0064] Example 4 is carried out with reference to Example 1, the difference is that the mass fraction of titanium dioxide in the radiative cooling finishing agent 10 is 10%, and at 25 °C, the viscosity of the radiative cooling finishing agent 10 is 140 CPS.

[0065] Example 5

[0066] Example 5 is carried out with reference to Example 1, the difference is that the mass fraction of titanium dioxide in the radiative cooling finishing agent 10 is 20%, and at 25 °C, the viscosity of the radiative cooling finishing agent 10 is 230 CPS.

[0067] Example 6

[0068] Example 6 was carried out with reference to Example 1, except that the mass fraction of titanium dioxide in the radiative cooling finishing agent 10 was 50%, and at 25 °C, the viscosity of the radiative cooling finishing agent 10 was 276 CPS.

[0069] Example 7

[0070] Example 7 was carried out with reference to Example 3, except that titanium dioxide was replaced by silicon dioxide. The solar reflectance of silicon dioxide in the 0.3 μm - 2.5 μm band was 70.4%, the emissivity in the 8 μm - 13 μm atmospheric window band was 80.2%, and at 25 °C, the viscosity of the radiative cooling finishing agent 10 was 95 CPS.

[0071] Example 8

[0072] Example 8 was carried out with reference to Example 3, except that titanium dioxide was replaced by barium sulfate. The solar reflectance of barium sulfate in the 0.3 μm - 2.5 μm band was 88.8%, the emissivity in the 8 μm - 13 μm atmospheric window band was 90.1%, and at 25 °C, the viscosity of the radiative cooling finishing agent 10 was 110 CPS.

[0073] Example 9

[0074] Example 9 was carried out with reference to Example 3, except that the mass fraction of cetyltrimethylammonium bromide dispersant in the radiative cooling finishing agent 10 was 1.6%, and the viscosity of the radiative cooling finishing agent 10 was 114 CPS.

[0075] Example 10

[0076] Example 10 was carried out with reference to Example 3, except that the mass fraction of sodium dodecyl sulfate dispersant in the radiative cooling finishing agent 10 was 2%, and the viscosity of the radiative cooling finishing agent 10 was 120 CPS.

[0077] Example 11

[0078] Example 11 was carried out with reference to Example 3, except that the mass fraction of polyvinyl alcohol binder in the radiative cooling finishing agent 10 was 6%, and the viscosity of the radiative cooling finishing agent 10 was 110 CPS.

[0079] Example 12

[0080] Example 12 was carried out with reference to Example 3, except that the mass fraction of polyurethane emulsion binder in the radiative cooling finishing agent 10 was 7%, and the viscosity of the radiative cooling finishing agent 10 was 125 CPS.

[0081] Example 13

[0082] Example 13 was carried out with reference to Example 3, except that the radiation cooling finishing agent 10 did not include a dispersant, and the viscosity of the radiation cooling finishing agent 10 was 69 CPS.

[0083] Example 14

[0084] Example 14 was carried out with reference to Example 1, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0085] Example 15

[0086] Example 15 was carried out with reference to Example 2, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0087] Example 16

[0088] Example 16 was carried out with reference to Example 3, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0089] Example 17

[0090] Example 17 was carried out with reference to Example 4, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0091] Example 18

[0092] Example 18 was carried out with reference to Example 5, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0093] Example 19

[0094] Example 19 was carried out with reference to Example 6, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0095] Example 20

[0096] Example 20 was carried out with reference to Example 7, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0097] Example 21

[0098] Example 21 was carried out with reference to Example 8, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0099] Example 22

[0100] Example 22 was carried out with reference to Example 9, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0101] Example 23

[0102] Example 23 was carried out with reference to Example 10, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0103] Example 24

[0104] Example 24 was carried out with reference to Example 11, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0105] Example 25

[0106] Example 25 was carried out with reference to Example 12, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0107] Example 26

[0108] Example 26 was carried out with reference to Example 13, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0109] Comparative Example 1

[0110] Polyacrylonitrile was dissolved in water to obtain an electrospinning solution, wherein the mass fraction of polyacrylonitrile in the electrospinning solution was 20%, and the electrospinning solution was used to obtain a polyacrylonitrile fiber membrane 20 by electrospinning technology.

[0111] As Figure 2 shown, are the scanning electron microscope images of the polyacrylonitrile fiber membrane 20 obtained in Comparative Example 1 and the radiative cooling fiber membranes obtained in Examples 1-5. It can be Figure 2 seen that the polyacrylonitrile fiber structure in the radiative cooling fiber membranes obtained in Examples 1-5 is complete.

[0112] As Figure 3 shown, are the transmission electron microscope images of the fibers in the radiative cooling fiber membrane obtained in Example 3 at different magnifications. It can be Figure 3 seen that titanium dioxide is uniformly formed on the fiber surface.

[0113] Comparative Example 2

[0114] Comparative Example 2 was carried out with reference to Example 3, except that the radiative cooling finishing agent 10 did not include a binder, and the viscosity of the radiative cooling finishing agent 10 was 4 CPS.

[0115] Comparative Example 3

[0116] Comparative Example 3 was carried out with reference to Example 3, except that the dispersant was replaced with sodium tripolyphosphate, the binder was replaced with phenolic-nitrile, the mass fraction of the dispersant in the radiative cooling finishing agent 10 was 0.2%, the mass fraction of the binder in the radiative cooling finishing agent 10 was 0.01%, and the viscosity of the radiative cooling finishing agent 10 was 5 CPS.

[0117] Comparative Example 4

[0118] Comparative Example 4 was carried out with reference to Example 3, except that the dispersant was replaced with ammonium polyacrylate salt, the binder was replaced with epoxy resin, the mass fraction of the dispersant in the radiative cooling finishing agent 10 was 5.5%, the mass fraction of the binder in the radiative cooling finishing agent 10 was 77%, and the viscosity of the radiative cooling finishing agent 10 was 350 CPS.

[0119] Comparative Example 5

[0120] Comparative Example 5 was carried out with reference to Comparative Example 1, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0121] Comparative Example 6

[0122] Comparative Example 6 was carried out with reference to Comparative Example 2, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0123] Comparative Example 7

[0124] Comparative Example 7 was carried out with reference to Comparative Example 3, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0125] Comparative Example 8

[0126] Comparative Example 8 was carried out with reference to Comparative Example 4, except that polyacrylonitrile was dissolved in N,N-dimethylacetamide to obtain an electrospinning solution.

[0127] It should be noted that in Examples 1-13 and Comparative Examples 1-4, the electrospinning solution may further include N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone, so that polyacrylonitrile can be better dissolved in the electrospinning solution. It should be noted that the polyacrylonitrile fibers in the examples of the present application can be prepared by conventional methods.

[0128] The optical properties of the radiative cooling fiber membranes obtained in Examples 1-26 above, the polyacrylonitrile fiber membranes 20 obtained in Comparative Examples 1 and 5, and the radiative cooling fiber membranes obtained in Comparative Examples 2-4 and 6-8 were tested. The test standards are as follows, and the test results are shown in Tables 1-2.

[0129] Solar reflectance (reflectance in the 0.3μm - 2.5μm band), visible light reflectance (reflectance in the 0.4μm - 0.78μm band), near-infrared light reflectance (reflectance in the 0.78μm - 2.5μm band): Conducted in accordance with the provisions of 6.4 in JG / T 235-2014;

[0130] Solar transmittance (reflectance in the 0.3μm - 2.5μm band): Tested in accordance with the provisions of GB / T 2680;

[0131] Ultraviolet transmittance (reflectance in the 0.3μm - 0.4μm band): Tested in accordance with the provisions of GB / T 2680;

[0132] Emissivity in the 8μm - 13μm atmospheric window is greater than or equal to 85%: Tested in accordance with the provisions of T / ZZB 2304-2021;

[0133] Tensile strength: Tested in accordance with the provisions of GB / T 1040.1 and GB / T 1040.3.

[0134] Table 1

[0135]

[0136]

[0137] Table 2

[0138]

[0139]

[0140] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0141] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A radiative cooling finishing agent, characterized in that, the radiative cooling finishing agent comprises radiative cooling particles, a binder, a dispersant and water, and at 25 °C, the viscosity of the radiative cooling finishing agent is 10 CPS - 300 CPS. Among them, the solar reflectance of the radiative cooling particles in the 0.3 μm - 2.5 μm band is greater than or equal to 70%, and the emissivity in the 8 μm - 13 μm atmospheric window is greater than or equal to 80%; the mass fraction of the radiative cooling particles in the radiative cooling finishing agent is 0.1% - 50%.

2. The radiative cooling finishing agent according to claim 1, characterized in that, the particle size of the radiative cooling particles is 2 nm - 1000 nm.

3. The radiative cooling finishing agent according to claim 1, characterized in that, the mass fraction of the radiative cooling particles in the radiative cooling finishing agent is 1% - 40%.

4. The radiative cooling finishing agent according to claim 1, characterized in that, the radiative cooling particles comprise at least one of titanium dioxide, silicon dioxide, barium sulfate, pearlescent powder, heavy calcium powder, alumina, zinc oxide, zirconia, cerium oxide, lanthanum oxide, talc powder, zinc sulfide, ceramic powder or magnesium oxide.

5. The radiative cooling finishing agent according to any one of claims 1 - 4, characterized in that, the mass ratio of the radiative cooling particles to the binder is 1:5 - 2.5:

1.

6. The radiative cooling finishing agent according to any one of claims 1 - 4, characterized in that, the binder comprises at least one of polyurethane, aqueous polyacrylic acid, polyethylene oxide, polyvinyl alcohol or polyethylene glycol; and / or, the dispersant comprises at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecyl carboxylate or cetyltrimethylammonium bromide, and the mass fraction of the dispersant in the radiative cooling finishing agent is less than or equal to 2%.

7. A radiative cooling fiber membrane, characterized in that, the radiative cooling fiber membrane comprises a fiber membrane and a radiative cooling coating provided on the surface of the fibers in the fiber membrane, wherein the radiative cooling coating is formed after drying the radiative cooling finishing agent according to any one of claims 1 - 6.

8. The radiative cooling fiber membrane according to claim 7, characterized in that, the material of the fiber membrane comprises at least one of polyacrylonitrile, polyvinyl alcohol, polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinylpyrrolidone, nylon 4,6, nylon 6 or polyimide.

9. A preparation method of a radiative cooling fiber membrane, characterized in that, comprises the following steps providing a fiber membrane; and forming the radiative cooling finishing agent according to any one of claims 1 - 6 on the fiber membrane by means of padding, and drying to obtain the radiative cooling fiber membrane.

10. A textile, characterized in that, the textile is made of the radiative cooling fiber membrane according to claim 7 or 8.

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