One-way moisture-conducting colored passive radiation cooling coated fabric and preparation method thereof

Abstract

The invention discloses a one-way moisture conduction type colored passive radiation cooling coated fabric and a preparation method thereof. The one-way moisture conduction type colored passive radiation cooling coated fabric comprises a fiber fabric, a daytime passive radiation coating, a modified inorganic pigment coating and a hydrophobic coating, wherein the daytime passive radiation coating and the modified inorganic pigment coating are sequentially coated on the surface of one side of the fiber fabric; the hydrophobic coating is coated on the surface of the other side of the fiber fabric; the daytime passive radiation coating is a hydrophilic inorganic nanoparticle coating; the particle size distribution of the inorganic particles is nanoscale; the preparation method of the modified inorganic pigment comprises the following steps: ball-milling an inorganic pigment, adding the ball-milled inorganic pigment into an organic solvent, adding an inorganic non-metallic material, uniformly mixing, standing, taking an upper-layer solution, and drying to obtain inorganic non-metallic microspheres of which the surfaces are adsorbed with the inorganic pigment; and calcining the inorganic nonmetal microspheres with the inorganic pigment adsorbed on the surfaces to obtain the modified inorganic pigment. The one-way moisture conduction type colored passive radiation cooling coated fabric realizes radiation cooling and one-way moisture conduction on the basis of colors, and has great significance in the field of energy conservation and environmental protection.

Description

Technical Field

[0001] The present invention relates to the technical field of passive radiation refrigeration materials, in particular to a unidirectional moisture-conducting colored passive radiation cooling coating fabric and a preparation method thereof. Background Art

[0002] As global temperatures continue to rise and extreme weather events become increasingly frequent, a growing number of heat-related illnesses threaten the health of workers exposed to outdoor environments. Faced with this situation, a solution is urgently needed. Radiative cooling is a method that achieves passive radiative cooling by utilizing the inherent properties of the material without external energy input. Daytime passive radiative cooling materials utilize their high reflectivity to sunlight and high mid-infrared emissivity at the atmospheric window (8-13 μm) to transfer heat from the atmospheric window to outer space via radiation, thereby achieving a cooling effect without any energy input. However, applying radiative cooling in conjunction with evaporative heat dissipation to the development of unidirectional moisture-conducting materials remains a significant challenge. This material has great potential for energy conservation and improved thermal comfort. If it can be industrialized, it will significantly reduce energy consumption and improve human thermal and moisture comfort.

[0003] In the current research on daytime passive radiation cooling materials, in order to ensure that the materials have high reflectivity to sunlight, the cooling materials are designed to be white. However, for aesthetic reasons, pure white cannot meet the actual application requirements in real life.

[0004] Chinese patent publication CN118345559A discloses a nanofiber membrane that promotes evaporative cooling of human sweat. The super-hygroscopic nanofiber membrane is produced through electrospinning. This method uses the super-hygroscopic nanofiber membrane to absorb moisture from the human microenvironment, creating a water vapor pressure gradient between the body surface and the microenvironment. This promotes sweat evaporation and heat dissipation from the body surface, significantly reducing skin surface temperature.

[0005] Chinese patent publication CN118007413A discloses an all-weather, multi-scenario cooling cellulose fabric. This is achieved by in-situ growing silica on the surface of a cellulose fabric. Cellulose acetate is then sprayed on one side of the treated cellulose fabric and an alkaline solution on the other. This all-weather, multi-scenario cooling cellulose fabric combines cooling and perspiration-wicking properties with high stability, breathability, and skin-friendliness. Summary of the Invention

[0006] The present invention provides a unidirectional moisture-conducting colored passive radiation cooling coating fabric, which overcomes the problems of monotonous color, complex preparation method and high cost of the radiation cooling coating in the prior art, and is conducive to the industrial application of unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0007] The technical solutions of the present invention are as follows: A unidirectional moisture-conducting colored passive radiation cooling coating fabric comprises a fiber fabric, a daytime passive radiation coating and a modified inorganic pigment coating sequentially coated on one side of the fiber fabric, and a hydrophobic coating coated on the other side of the fiber fabric; The daytime passive radiation coating is a hydrophilic inorganic nanoparticle coating; the particle size distribution of the inorganic particles is nanometer-level, the solar reflectivity is above 90%, and the mid-infrared radiation rate is above 85%; The preparation method of the modified inorganic pigment comprises: The inorganic pigment is ball-milled and added to an organic solvent, and then an inorganic non-metallic material is added and mixed evenly, and the upper layer of the solution is taken after standing, and dried to obtain inorganic non-metallic microspheres with the inorganic pigment adsorbed on the surface; The inorganic non-metallic microspheres with inorganic pigments adsorbed on the surface are calcined to obtain modified inorganic pigments.

[0008] The colored passive radiation cooling coating fabric of the present invention realizes a unidirectional wetting gradient of sweat by constructing a difference in water contact angles of the hydrophilic and hydrophobic layers, thereby achieving a unidirectional moisture conduction effect; in addition, the modified inorganic pigment is an inorganic pigment-wrapped inorganic non-metal composite particle, and the vibration of the anion groups and specific groups (such as water molecules, carbonate ions, etc.) constituting the inner core layer of the composite particles presents a specific absorption frequency in the infrared spectrum, which can generate strong infrared radiation, and help to improve the infrared emissivity of the fabric at the atmospheric window.

[0009] The colored passive radiation cooling coating fabric of the present invention has a unidirectional moisture-conducting effect. At the same time, the modified inorganic pigment can enhance the radiation efficiency of the passive radiation coating during the day, thereby achieving a dual cooling effect and improving the thermal and moisture comfort of the human body.

[0010] The inorganic non-metallic material is at least one of silicon dioxide, aluminum oxide, zirconium oxide, silicate glass and borate glass.

[0011] The particle size of the inorganic non-metallic material is 30~60μm.

[0012] The inorganic pigment is at least one of iron oxide yellow, iron oxide red and iron blue. The inorganic pigment has high reflectivity.

[0013] The mass ratio of the inorganic non-metallic material to the inorganic pigment is 1:3-6.

[0014] The inorganic nanoparticles are at least one of silicon dioxide, titanium dioxide, aluminum oxide, aluminum phosphate, and barium sulfate particles.

[0015] The particle size of the inorganic nanoparticles is 50-1000 nm.

[0016] The inorganic nanoparticle coating has high reflectivity to visible light-near infrared sunlight and high emissivity in the 8-13 μm atmospheric window.

[0017] In order to improve the bonding strength between inorganic nanoparticles and fabrics, preferably, the preparation method of the daytime passive radiation coating includes: The hydrophilic adhesive is dissolved in an organic solvent, and then inorganic nanoparticles are dispersed therein and stirred to obtain an inorganic nanoparticle dispersion; the inorganic nanoparticle dispersion is sprayed on the surface of the fabric and dried to obtain a daytime passive radiation coating.

[0018] The present invention utilizes a hydrophilic adhesive to combine inorganic nanoparticles onto fabrics, which not only improves the adhesion strength of the inorganic nanoparticles but also makes the fabric hydrophilic.

[0019] The hydrophilic adhesive is at least one of polyoxypropylene glycol, polyethylene glycol, poloxamer, ethylene oxide-propylene oxide copolymer, carboxymethyl cellulose, hydroxyethyl cellulose, and polyether.

[0020] The mass ratio of the hydrophilic adhesive to the organic solvent is 1:20-30.

[0021] The organic solvent is tetrahydrofuran.

[0022] In the inorganic nanoparticle dispersion, the mass fraction of the inorganic nanoparticles is 5-40%.

[0023] In the inorganic nanoparticle dispersion, the mass ratio of the inorganic nanoparticles to the hydrophilic adhesive is 1:0.1-0.3.

[0024] More preferably, in the inorganic nanoparticle dispersion, the mass fraction of the inorganic nanoparticles is 20-30%.

[0025] When the amount of passive radiation coating applied during the day is appropriate, it scatters light, increasing the fabric's reflectivity. However, when the amount applied is too high, the scattering centers become too dense, causing light to scatter multiple times within the coating. Some light will deviate from the reflection direction, while some will be scattered into the coating and absorbed, reducing the fabric's reflectivity. When the amount applied is too low, some light will not be reflected but will be transmitted through the fabric, resulting in a relatively low reflectivity.

[0026] Preferably, the mass ratio of the daytime passive radiation coating to the fiber fabric per unit area is 1:0.5-1.5.

[0027] The fiber fabric is cotton fabric, linen fiber fabric, viscose fabric, Tencel fiber fabric, Modal fiber fabric and the like.

[0028] The preparation method of the modified inorganic pigment coating comprises: The modified inorganic pigment is dispersed in an organic solvent to obtain a modified inorganic pigment suspension, the modified inorganic pigment suspension is sprayed on the daytime passive radiation coating, and dried to obtain a modified inorganic pigment coating.

[0029] The coating amount of the modified inorganic pigment coating is 5-15 mg / cm 2 .

[0030] The water contact angle of the hydrophobic coating is greater than 130°.

[0031] The hydrophobic coating is at least one of a polydimethylsiloxane coating, a polytetrafluoroethylene coating, a silicone resin coating, and a methyltrichlorosilane coating.

[0032] The coating amount of the hydrophobic coating is 0.01~0.02 mg / cm 2 .

[0033] The present invention also provides a method for preparing the one-way moisture-conducting colored passive radiation cooling coating fabric, comprising the following steps: (1) dissolving a hydrophilic adhesive in an organic solvent, dispersing inorganic nanoparticles therein, and stirring to obtain an inorganic nanoparticle dispersion; The inorganic nanoparticle dispersion is coated on one side of the fiber fabric and dried to obtain a daytime passive radiation coating; (2) spraying the modified inorganic pigment suspension onto the daytime passive radiation coating and drying it to obtain the modified inorganic pigment coating; (3) The hydrophobic adhesive is dissolved in an organic solvent, and then sprayed on the other side of the fiber fabric and dried to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0034] Compared with the prior art, the present invention has the following beneficial effects: The unidirectional, moisture-conducting, colored passive radiative cooling fabric provided by this invention is fabricated through the composite assembly of multiple functional coatings. This allows ordinary fabrics to achieve both excellent visible and near-infrared solar reflectivity and strong mid-infrared emission in the atmospheric window (8-13 μm), enabling efficient radiative cooling under sunlight. The layered structure creates a wetting gradient, enabling directional perspiration transport, further enhancing cooling effectiveness and thermal comfort. Furthermore, the outermost inorganic pigment coating imparts a richer color to the fabric, eliminating the need for a highly reflective silver layer, resulting in lower costs and a wider range of applications.

[0035] The invention has low cost and simple operation, realizes radiation cooling and unidirectional moisture conduction on a color basis, and has great significance in the field of energy conservation and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the visible-near infrared reflection spectrum of the unidirectional moisture-conducting colored passive radiation cooling coating fabric in Example 2; Figure 2 This is an SEM image of the unidirectional moisture-conducting colored passive radiation cooling coating fabric in Example 2; Figure 3 The visible-near infrared reflection spectra of the inorganic pigment before and after modification in Example 2; Figure 4 This is a temperature comparison curve of the unidirectional moisture-conducting colored passive radiation cooling coating fabric in Example 2; Figure 5 This is a diagram showing the unidirectional moisture conduction performance of the unidirectional moisture conduction colored passive radiant cooling coating fabric in Example 2, (a) is the back side (hydrophobic side), and (b) is the colored side (hydrophilic side). DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be noted that the following examples are intended to facilitate understanding of the present invention and do not have any limiting effect on the present invention.

[0038] Example 1 The preparation method of inorganic pigment composite particles is as follows: (1) Add the inorganic pigment and alcohol solution into the ball mill, and after uniform ball milling, separate the pigment from the zirconium beads to obtain dispersed pigment; (2) Add the dispersed pigment to the organic solvent, mix well, then add the inorganic non-metallic material according to the corresponding proportion, use a cell crusher to ultrasonically disperse for 25 minutes, let it stand, take the upper layer of solution, and dry it to obtain the inorganic pigment composite particles.

[0039] The inorganic pigment composite particles are dispersed in an organic solvent to prepare an inorganic pigment composite particle suspension.

[0040] Example 2 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, 25 parts of silica and 3 parts of poloxamer (manufacturer: Tianzheng Pharmaceutical Co., Ltd.) were added to 60 parts of tetrahydrofuran and heated at 40°C for 2 hours to obtain a silica suspension.

[0041] 2) 2 parts of silicate glass (50 μm), 10 parts of yellow iron oxide pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0042] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0043] 4) Dipping the cotton fabric into the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0044] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0045] Figure 1 This is the reflectance spectrum of the unidirectional moisture-conducting colored passive radiation cooling coating fabric in Example 2 in the visible-near infrared band under an ultraviolet spectrophotometer. The unidirectional moisture-conducting colored fabric absorbs sunlight of specific wavelengths in the visible light band to present a colorful appearance, and still has a high reflectivity in the near-infrared band to ensure a good radiation cooling effect.

[0046] Figure 2 This is a microscopic structure of the surface of the unidirectional moisture-conducting colored passive radiation cooling coating fabric in Example 2 under a desktop scanning electron microscope. It can be observed that the inorganic particles for radiation cooling are fixed on the fabric by the polymer, and the inorganic pigments are attached to the surface of the particles.

[0047] Figure 3 1 is the visible-near-infrared reflectance spectrum of the inorganic pigment before and after modification in Example 2. The modified inorganic pigment has better visible-near-infrared reflectivity.

[0048] Figure 4 This is a temperature comparison curve of the unidirectional moisture-conducting colored passive radiant cooling coating fabric in Example 2 in an outdoor environment. It can be seen from the figure that the unidirectional moisture-conducting colored passive radiant cooling fabric has an excellent cooling effect, with a maximum temperature reduction of 5.2 degrees.

[0049] Figure 5 The moisture images of the front and back sides of the unidirectional moisture-conducting colored passive radiant cooling coating fabric in Example 2 under a liquid moisture tester, (a) is the back side (hydrophobic side), and (b) is the colored side (hydrophilic side). It can be seen from the figure that the unidirectional moisture-conducting colored passive radiant cooling fabric has an excellent unidirectional moisture-conducting effect.

[0050] Example 3 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of titanium dioxide and 3 parts of polyoxypropylene glycol to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0051] 2) 2 parts of silicate glass (50 μm), 10 parts of yellow iron oxide pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0052] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0053] 4) Dipping the cotton fabric into the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0054] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0055] Example 4 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, 25 parts of silicon dioxide and 3 parts of sodium carboxymethyl cellulose are added to 60 parts of tetrahydrofuran, and heated at 40°C for 2 hours to obtain a silicon dioxide suspension.

[0056] 2) 2 parts of silicate glass, 10 parts of yellow iron oxide pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0057] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0058] 4) Dipping the cotton fabric into the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0059] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0060] Example 5 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, 25 parts of silicon dioxide and 3 parts of hydroxyethyl cellulose are added to 60 parts of tetrahydrofuran, and heated at 40°C for 2 hours to obtain a silicon dioxide suspension.

[0061] 2) 2 parts of silicate glass, 10 parts of inorganic pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0062] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0063] 4) Dipping the cotton fabric into the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0064] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0065] Example 6 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of silica and 3 parts of polyether to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0066] 2) Inorganic pigment-coated silicate glass composite particles were prepared according to the method of Example 1 using 2 parts of aluminum oxide (40-50 μm), 10 parts of yellow iron oxide pigment, and 20 parts of anhydrous ethanol as an organic solvent. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0067] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0068] 4) Dipping the cotton fabric into the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0069] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0070] Example 7 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of silica and 3 parts of polyether to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0071] 2) 2 parts of silicate glass, 10 parts of inorganic pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0072] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0073] 4) Immersing the hemp fiber fabric in the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0074] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0075] Example 8 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of silica and 3 parts of polyether to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0076] 2) 2 parts of silicate glass, 10 parts of inorganic pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0077] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0078] 4) Immersing the viscose fabric in the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0079] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0080] Example 9 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of silica and 3 parts of polyether to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0081] 2) 2 parts of silicate glass, 10 parts of inorganic pigment, and 20 parts of anhydrous ethanol as an organic solvent are prepared according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles are dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0082] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0083] 4) Immersing the Tencel fiber fabric in the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0084] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0085] Example 10 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of silica and 3 parts of polyether to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0086] 2) 2 parts of silicate glass, 10 parts of inorganic pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0087] 3) Add 1 part of PDMS to 50 parts of tetrahydrofuran and stir to mix well.

[0088] 4) Immersing the modal fiber fabric in the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0089] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0090] Example 11 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of silica and 3 parts of polyether to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0091] 2) 2 parts of silicate glass, 10 parts of inorganic pigment, and 20 parts of anhydrous ethanol as an organic solvent are prepared according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles are dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0092] 3) Add 1 part of polytetrafluoroethylene to 50 parts of tetrahydrofuran and stir until evenly mixed.

[0093] 4) Dipping the cotton fabric into the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0094] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0095] Example 12 A unidirectional moisture-conducting colored passive radiation cooling coating fabric is prepared by the following steps: 1) According to the following weight ratio, add 25 parts of silica and 3 parts of polyether to 60 parts of tetrahydrofuran and heat at 40°C for 2 hours to obtain a silica suspension.

[0096] 2) 2 parts of silicate glass, 10 parts of inorganic pigment, and 20 parts of anhydrous ethanol as an organic solvent were used to prepare inorganic pigment-coated silicate glass composite particles according to the method of Example 1. The inorganic pigment-coated silicate glass composite particles were dispersed in the organic solvent to obtain an inorganic pigment composite particle suspension.

[0097] 3) Add 1 part of silicone resin (e.g. polydimethylsiloxane, manufactured by Shanghai MacLean Biochemical Technology Co., Ltd.) to 50 parts of tetrahydrofuran and stir until evenly mixed.

[0098] 4) Dipping the cotton fabric into the inorganic particle suspension prepared in step 1) 2-3 times and drying the fabric, then spraying the inorganic pigment composite particle suspension prepared in step 2) onto the fabric 1-2 times and drying the fabric to obtain a fabric having a hydrophilic layer.

[0099] Then, PDMS is sprayed on another fabric surface and dried to obtain a fabric with a hydrophobic layer. The fabric with a hydrophilic layer and the fabric with a hydrophobic layer are bonded together with a molten film, with both the hydrophilic and hydrophobic layers facing outward, to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

[0100] The unidirectional moisture-conducting colored passive radiation cooling coating fabrics prepared in Examples 3-12 have similar cooling and unidirectional moisture-conducting effects as those in Example 2.

[0101] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A one-way moisture-conducting colored passive radiation cooling coating fabric, characterized in that: The invention comprises a fiber fabric, a daytime passive radiation coating and a modified inorganic pigment coating sequentially coated on one side of the fiber fabric, and a hydrophobic coating coated on the other side of the fiber fabric; The daytime passive radiation coating is a hydrophilic inorganic nanoparticle coating; the particle size distribution of the inorganic particles is nanometer-level, the solar reflectivity is above 90%, and the mid-infrared radiation rate is above 85%; The preparation method of the modified inorganic pigment comprises: The inorganic pigment is ball-milled and added to an organic solvent, and then an inorganic non-metallic material is added and mixed evenly, and the upper layer of the solution is taken after standing, and dried to obtain inorganic non-metallic microspheres with the inorganic pigment adsorbed on the surface; The inorganic non-metallic microspheres with inorganic pigments adsorbed on the surface are calcined to obtain modified inorganic pigments.

2. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1, characterized in that: The inorganic non-metallic material is at least one of silicon dioxide, aluminum oxide, zirconium oxide, silicate glass and borate glass.

3. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1, characterized in that: The inorganic pigment is at least one of iron oxide yellow, iron oxide red and iron blue.

4. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1, characterized in that: The inorganic nanoparticles are at least one of silicon dioxide, titanium dioxide, aluminum oxide, aluminum phosphate, and barium sulfate particles.

5. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1, characterized in that: The preparation method of the daytime passive radiation coating includes: The hydrophilic binder is dissolved in an organic solvent, and then inorganic nanoparticles are dispersed therein and stirred to obtain an inorganic nanoparticle dispersion; the inorganic nanoparticle dispersion is sprayed on the surface of the fabric and dried to obtain a daytime passive radiation coating.

6. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1 or 5, characterized in that: The mass ratio of the daytime passive radiation coating to the fiber fabric per unit area is 1:0.5~1.

5.

7. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1, characterized in that: The preparation method of the modified inorganic pigment coating comprises: The modified inorganic pigment is dispersed in an organic solvent to obtain a modified inorganic pigment suspension, the modified inorganic pigment suspension is sprayed on the daytime passive radiation coating, and dried to obtain a modified inorganic pigment coating.

8. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1 or 7, characterized in that: The coating amount of the modified inorganic pigment coating is 5-15 mg / cm 2 .

9. The one-way moisture-conducting colored passive radiation cooling coating fabric according to claim 1, characterized in that: The water contact angle of the hydrophobic coating is greater than 130°.

10. A method for preparing the unidirectional moisture-conducting colored passive radiation cooling coating fabric according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) dissolving a hydrophilic adhesive in an organic solvent, dispersing inorganic nanoparticles therein, and stirring to obtain an inorganic nanoparticle dispersion; The inorganic nanoparticle dispersion is coated on one side of the fiber fabric and dried to obtain a daytime passive radiation coating; (2) spraying the modified inorganic pigment suspension onto the daytime passive radiation coating and drying it to obtain the modified inorganic pigment coating; (3) The hydrophobic adhesive is dissolved in an organic solvent, and then sprayed on the other side of the fiber fabric and dried to obtain a unidirectional moisture-conducting colored passive radiation cooling coating fabric.

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