A method for preparing a passive cooling fiber material and fabric

Abstract

The application relates to a preparation method of a passive cooling fiber material and fabric, which is spontaneously cooled through direct regulation of energy absorption and dissipation on the surface without consuming conventional energy. The method comprises the following steps: mixing high-refractive inorganic micro-nano particles, a modifier and a polymer base to obtain a composite material master batch, then performing composite extrusion molding in a spinning assembly, and winding to obtain the passive cooling fiber material. The application adopts a melt spinning method, effectively controls the dispersion degree of the high-refractive inorganic micro-nano particles in the fiber by using the modifier, that is, the size and distribution of the micro-nano particle aggregates, so that the optical properties and mechanical properties of the fiber are changed, and finally the passive cooling fiber material with precise solar radiation regulation function is obtained. The passive cooling fiber material and the fabric prepared by the application have excellent passive cooling performance and mechanical properties, and have the advantages of large-scale batch preparation, low cost and high production efficiency.

Description

Technical Field

[0001] This application relates to the field of functional textiles, and in particular to a method for preparing a passive cooling fiber material and fabric. Background Technology

[0002] Global warming has triggered a series of serious environmental problems, such as extreme weather, sea-level rise, forest fires, and species extinction, posing a severe challenge to sustainable socio-economic development. According to the Copernicus Climate Change Service (CCCS) of the European Union, global temperatures reached a record high in 2023, with the global average temperature exceeding pre-industrial levels by an unprecedented 1.48 degrees Celsius, and it is highly likely that the temperature will exceed the 1.5-degree Celsius warming threshold for the first time in 2024. High temperatures have caused serious harm to human health: between 2000 and 2019, it is estimated that approximately 489,000 people worldwide die annually from heat-related illnesses. Therefore, taking timely preventative measures to avoid the harm caused by high temperatures is essential.

[0003] However, for people who work or engage in outdoor activities, it is difficult to carry active cooling devices such as air conditioners and fans with them, and they cannot avoid absorbing a large amount of solar radiation heat, making daytime cooling a significant challenge. Passive cooling materials utilize their high reflectivity to sunlight (0.3-2.5μm) and high mid-infrared emissivity in the atmospheric window (8-13μm) to radiate heat from the atmospheric window to outer space, thereby achieving a cooling effect without any energy input.

[0004] However, based on existing public reports, many passive cooling devices have not yet met the requirements for good wearability and efficient passive cooling under direct sunlight conditions. Fabrics, due to their excellent breathability, softness, and wearability, are the only suitable form of device for passive cooling outdoors. However, examples of modifying fibers, yarns, and fabrics to achieve passive cooling are still limited. Existing research mainly focuses on the following aspects:

[0005] Patent document 1 discloses a method for preparing high-efficiency radiative cooling fibers. First, a polymer melt is extruded and cooled to obtain nascent fibers. Then, a modified slurry containing core-shell structured radiative cooling particles is sprayed onto the nascent fibers for modification. Finally, after oiling, the fibers are spun, stretched, and wound to obtain the high-efficiency radiative cooling fibers. This invention achieves radiative cooling by combining the outward radiation of far-infrared rays from the shell layer of the core-shell structured radiative cooling particles with the reflection of visible and near-infrared light from the external environment. However, the sprayed modified slurry may detach during subsequent stretching and mechanical friction, affecting the cooling effect and user experience.

[0006] Patent document 2 proposes a radiation-cooling functional layer, a radiation-cooling fabric, and a method for preparing the same. The radiation-cooling fabric comprises a flexible substrate layer and a radiation-cooling functional layer. The radiation-cooling functional layer is composed of a radiation-cooling functional resin and radiation-cooling functional powder, exhibiting high radiation-cooling efficiency and effectively expanding the application scenarios of radiation-cooling fabrics. However, the radiation-cooling layer involved in this method inevitably affects the inherent breathability, moisture permeability, and drape of the fabric, making it unsuitable for the preparation of apparel fabrics.

[0007] Patent document 3 proposes a colored passive radiation cooling fabric. Through a combination of multiple functional coatings, commercial fibers and fabrics possess high visible-near-infrared light reflectance and mid-infrared atmospheric window (8–13 μm) radiation, thereby achieving efficient radiation cooling under solar irradiation. Simultaneously, the outermost layer is coated with a colored coating, giving the fabric a rich and varied appearance, thus broadening its application range. However, this invention only involves surface coatings on the fibers and does not involve innovations in structural design or process technology during fiber material preparation.

[0008] Patent document 4 discloses a spectrally adjustable radiation-cooled biomass material and its preparation method. Cellulose raw materials are dissolved in an organic solvent, and a pore-forming agent and surfactant are added. After stirring at room temperature, the emulsion is prepared by casting or coating to obtain the radiation-cooled biomass material. This material exhibits excellent radiation-cooling performance, and its optical properties can be effectively controlled by designing the material's pore size. However, this method has limited application in the field of radiation-cooled fabrics, and the preparation process uses a large amount of organic solvent, which has an impact on the environment and the health of workers, making it unsuitable for large-scale production.

[0009] Patent document 5 discloses a superhydrophobic daytime passive radiation cooling fabric. This fabric consists of a fiber fabric, a daytime passive radiation coating, and a superhydrophobic coating, wherein the daytime passive radiation coating is an aluminum phosphate radiation particle coating. Furthermore, the outermost superhydrophobic coating gives the fiber fabric excellent stain resistance and self-cleaning properties. However, the multiple layers of coatings can make the fabric heavy, affecting its original skin-friendliness and comfort; moreover, they are prone to wear and tear during daily wear, impacting the radiative cooling effect.

[0010] Current research on fibers and fabrics with passive cooling capabilities mainly focuses on passive radiation cooling coatings. These coatings, possessing high solar irradiance reflectivity and high-mid-infrared emissivity, achieve effective cooling in the final fabric. However, passive cooling fabrics with additional coatings often suffer from poor wearing comfort and are prone to problems such as poor breathability and sweating, making them unsuitable for use in actual apparel fabrics. Therefore, it is necessary to address the structural design, material selection, and manufacturing processes of fibers to produce passive cooling optical metamaterial fibers with precise solar radiation regulation and good mechanical properties. These fibers, after spinning, weaving, and finishing processes, can ultimately yield passive cooling fabrics that combine broad-spectrum regulation with wearable comfort.

[0011] Existing technical documents

[0012] Patent Document 1: CN 111576044 B Publication Text

[0013] Patent Document 2: CN 110777543 B Publication Text

[0014] Patent Document 3: CN 115365097 B Publication Text

[0015] Patent Document 4: CN 115521498 B Publication Text

[0016] Patent document 5: CN 111607983 B published text. Summary of the Invention

[0017] To address the aforementioned issues, this application provides a method for preparing passive cooling fiber materials and fabrics. Through the selection of high-refractive-index inorganic micro / nano particles, the selection of modifiers, the selection of polymer substrates, and the design of fiber, yarn, and fabric structures, passive cooling fiber materials and fabrics with precise solar radiation control capabilities are obtained. Specifically, a melt spinning method is employed, utilizing modifiers to effectively control the dispersion of high-refractive-index inorganic micro / nano particles within the fiber, thereby altering the fiber's optical and mechanical properties, ultimately achieving effective control over the optical properties of the passive cooling fiber materials and fabrics.

[0018] The specific technical solution of this application is as follows:

[0019] Item 1. A passive cooling fiber material, comprising high refractive index inorganic micro / nano particles, a modifier, and a polymer substrate material;

[0020] The high-refractive-index inorganic micro / nano particles have a particle size of 0.02-5 μm.

[0021] The mass ratio of the modifier to the high refractive index inorganic micro / nanoparticles is 1:1-1:100, preferably 1:2.5-1:10, and more preferably 1:6.7-1:10.

[0022] The high-refractive-index inorganic micro / nano particles account for 0.5%-30% of the mass fraction of the passive cooling fiber material; preferably 2.0%-20%; more preferably 5.0%-20%.

[0023] The modifier accounts for 0%-15% of the mass fraction of the passive cooling fiber material; preferably 0.2%-2.0%; more preferably 1.0%-2.0%.

[0024] Item 2. The passive cooling fiber material according to Item 1, wherein the particle size of the high refractive index inorganic micro / nano particles is 0.2-2.0 μm, preferably 0.2-0.8 μm.

[0025] Item 3. The passive cooling fiber material according to Item 1, wherein the diameter of the passive cooling fiber material is in the range of 10μm-80μm, preferably 10-30μm, and more preferably 10-20μm.

[0026] Item 4. The passive cooling fiber material according to Item 1, wherein the polymer base material is selected from any one or more of polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polylactic acid (PLA), polyolefin, polycarbonate (PC), polyphenylene sulfide (PPS), polyoxymethylene, and polyethylene (PO).

[0027] Preferably, the polymer substrate material is polyethylene terephthalate (PET) or polylactic acid (PLA);

[0028] The high-refractive-index inorganic micro / nanoparticles are selected from any one or two or more of titanium dioxide, zinc sulfide, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, hexagonal boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, and calcium sulfate.

[0029] Preferably, the high-refractive-index inorganic micro / nano particles have a particle size of 0.02-5 μm, more preferably 0.2-2.0 μm, and even more preferably 0.2-0.8 μm;

[0030] Preferably, the high-refractive-index inorganic micro / nano particles are titanium dioxide or zinc oxide;

[0031] The modifier is selected from any one or more of the following: cetyltrimethylammonium bromide (CTAB), polyvinyl alcohol (PVA), polyvinyl butyral, medium molecular weight polyethylene (PE), phthalate, aliphatic diester, fatty acid ester, polyphenol ester, polyol ester, epoxy hydrocarbon, and alkyl sulfonate.

[0032] Preferably, the modifier is polyvinyl alcohol or polyvinyl butyral;

[0033] More preferably, the modifier is polyvinyl alcohol, and the dynamic viscosity of the polyvinyl alcohol is 5-120 mPa·s.

[0034] Item 5. A method for preparing a passive cooling fiber material, comprising:

[0035] High-refractive-index inorganic micro / nano particles, modifiers, and polymer substrates are mixed in a weight ratio to prepare composite material masterbatch.

[0036] The composite masterbatch is compounded and extruded in a spinning assembly, and then wound to obtain a passive cooling fiber material.

[0037] Item 6. The method according to Item 5, wherein,

[0038] The high-refractive-index inorganic micro / nano particles have a particle size of 0.02-5 μm.

[0039] The mass ratio of the modifier to the high refractive index inorganic micro / nanoparticles is 1:1-1:100, preferably 1:2.5-1:10, and more preferably 1:6.7-1:10.

[0040] The high-refractive-index inorganic micro / nano particles account for 0.5%-30% of the mass fraction of the passive cooling fiber material; preferably 2.0%-20%; more preferably 5.0%-20%.

[0041] The modifier accounts for 0%-15% of the mass fraction of the passive cooling fiber material; preferably 0.2%-2.0%; more preferably 1.0%-2.0%.

[0042] Item 7. The method according to Item 5, wherein the particle size of the high refractive index inorganic micro / nano particles is 0.2-2.0 μm, preferably 0.2-0.8 μm.

[0043] Item 8. The method according to Item 5, wherein the diameter of the passive cooling fiber material is in the range of 10μm-80μm, preferably 10-30μm, and more preferably 10-20μm.

[0044] Item 9. The method according to any one of items 5-8, wherein the polymer substrate material is selected from any one or more of polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polylactic acid (PLA), polyolefin, polycarbonate (PC), polyphenylene sulfide (PPS), polyoxymethylene, and polyethylene (PO).

[0045] Preferably, the polymer substrate material is polyethylene terephthalate (PET) or polylactic acid (PLA);

[0046] The high-refractive-index inorganic micro / nanoparticles are selected from any one or two or more of titanium dioxide, zinc sulfide, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, hexagonal boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, and calcium sulfate.

[0047] Preferably, the particle size of the micro-nano particles is 0.03-5 μm, more preferably 0.2-2.0 μm, and even more preferably 0.2-0.8 μm;

[0048] Preferably, the high-refractive-index inorganic micro / nano particles are titanium dioxide or zinc oxide;

[0049] The modifier is selected from any one or more of the following: cetyltrimethylammonium bromide (CTAB), polyvinyl alcohol (PVA), polyvinyl butyral, medium molecular weight polyethylene (PE), phthalate, aliphatic diester, fatty acid ester, polyphenol ester, polyol ester, epoxy hydrocarbon, and alkyl sulfonate.

[0050] Preferably, the modifier is polyvinyl alcohol or polyvinyl butyral;

[0051] More preferably, the modifier is polyvinyl alcohol, and the dynamic viscosity of the polyvinyl alcohol is 5-120 mPa·s.

[0052] Item 10. The method according to any one of items 5-8, wherein the composite material masterbatch is prepared into the passive cooling fiber material by using one or more of the following methods: melt spinning, wet spinning, hot drawing, electrospinning, and meltblown spinning, preferably melt spinning or hot drawing.

[0053] Item 11. The method according to Item 10, wherein the passive cooling fiber material is a filament and / or a staple fiber.

[0054] Item 12. A passive cooling fiber material fabric, wherein the passive cooling fiber material prepared by any one of the preparation methods described in Items 5 to 11 is obtained by spinning, weaving, heat setting and other processes.

[0055] The method for preparing passive cooling fiber materials and fabrics in this application has the following advantages over the prior art:

[0056] 1. The passive cooling fiber material prepared in this application is prepared from high-refractive-index inorganic micro-nano particles, modifiers, and polymer substrates. The polymer substrate material ensures that the fiber has good mechanical processing properties and flexibility, which can meet the requirements of subsequent large-scale spinning, weaving, and finishing. Inorganic micro-nano particles with different refractive indices are uniformly distributed inside the polymer substrate material, and the dispersion degree of high-refractive-index inorganic micro-nano particles inside the fiber is effectively controlled by the modifier, that is, the size and distribution of the nanoparticle aggregates, thereby changing the optical properties and mechanical properties of the fiber, and finally obtaining a passive cooling fiber material with precise solar radiation control function.

[0057] The fabric of this application generates a selective optical response in the solar radiation band based on the optical structure and material design of fibers, yarns and fabrics, thereby achieving the guidance and manipulation of solar radiation. It achieves efficient band solar radiation management by spectral modulation of the optical interaction between solar radiation, fabric and human skin, and has the advantages of large-scale batch production, low cost and high production efficiency. Attached Figure Description

[0058] Figure 1 This is a schematic diagram illustrating the optimization of nanoparticle dispersion in passive cooling fiber materials.

[0059] Figure 2 This is a SEM image of the passive cooling fiber material obtained in Example 4.

[0060] Figure 3 The image shows a SEM image of the yarn obtained by spinning the passive cooling fiber material obtained in Example 4.

[0061] Figure 4 This is a graph showing the reflectance data of the melt-spun passively cooled optical metamaterial fabric obtained in Example 4.

[0062] Figure 5 This is a photograph of the melt-spun passively cooled optical metamaterial fabric obtained in Example 4. Detailed Implementation

[0063] The specific embodiments of this application are described in detail below, but it should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of this application. Experimental methods in the examples below that do not specify specific experimental conditions are generally operated under conventional conditions or as recommended by the manufacturer.

[0064] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated ingredients or components without excluding other ingredients or other components.

[0065] In one aspect, this application provides a passive cooling fiber material, comprising high-refractive-index inorganic micro / nano particles, a modifier, and a polymer substrate material.

[0066] The passive cooling method in this application achieves the purpose of cooling or reducing the cooling load by selectively and rationally utilizing solar and thermal radiation and by directly adjusting the energy absorption and dissipation of the surface without consuming conventional energy.

[0067] In this application, the "diameter of the passive cooling fiber material" refers to the diameter of a single passive cooling fiber material. The diameter of the passive cooling fiber material can be obtained by taking an image with a scanning electron microscope (SEM) and measuring and calculating it from the image according to the scale. The diameter directly measured from the electron microscope image can be used as the diameter of the passive cooling fiber material. Passive cooling fiber materials with a diameter of 10μm-80μm can be, for example, passive cooling fiber materials with diameters of 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, etc.; preferably, the diameter of the passive cooling fiber material is 10-30μm, more preferably 10-20μm.

[0068] In one specific embodiment, the particle size of the high-refractive-index inorganic micro / nanoparticles is 0.02-5 μm, for example, it can be 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2... The particle sizes are 0.8 μm, 3.0 μm, 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4.0 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm, 5.0 μm, etc.; preferably, the particle size of the high-refractive-index inorganic micro / nano particles is 0.2-2.0 μm, for example, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, etc.; more preferably, it is 0.2-0.8 μm. In this application, the particle size of the high-refractive-index inorganic micro / nano particles refers to the average particle size obtained by dynamic light scattering method.

[0069] In one specific embodiment, the mass ratio of the modifier to the high-refractive-index inorganic micro / nanoparticles is 1:1 to 1:100, for example, it can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:11, 1:12, 1:13, or 1:1 4. 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, 1:100, etc.; preferably, the mass ratio of the modifier to the high refractive index inorganic micro / nano particles is 1:2.5-1:10, more preferably 1:6.7-1:10.

[0070] In one specific embodiment, high-refractive-index inorganic micro / nano particles are dispersed in different aggregation states within the passive cooling fiber material, accounting for 0.5%-30% of the mass fraction of the passive cooling fiber material; for example, they can be 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.; preferably, the high-refractive-index inorganic micro / nano particles account for 2.0%-20% of the mass fraction of the passive cooling fiber material; more preferably, 5.0%-20%.

[0071] In one specific embodiment, the modifier accounts for 0%-15% of the mass fraction of the passive cooling fiber material, for example, it can be 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10%, 11%, 12%, 13%, 14%, 15%, etc.; preferably, the modifier accounts for 0.2%-2.0% of the mass fraction of the passive cooling fiber material; more preferably, it is 1.0%-2.0%.

[0072] In one specific embodiment, the polymer substrate material is selected from any one or more of polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polylactic acid (PLA), polyolefin, polycarbonate (PC), polyphenylene sulfide (PPS), polyoxymethylene, and polyethylene (PO).

[0073] Preferably, the polymer substrate material is polyethylene terephthalate (PET) or polylactic acid (PLA).

[0074] In one specific embodiment, the high refractive index inorganic micro / nanoparticles are selected from any one or two or more of titanium dioxide, zinc sulfide, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, hexagonal boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, and calcium sulfate.

[0075] Preferably, the high-refractive-index inorganic micro / nano particles are titanium dioxide or zinc oxide; more preferably, the high-refractive-index inorganic micro / nano particles are titanium dioxide, wherein the particle size of titanium dioxide is 0.02-5 μm; preferably, the particle size of titanium dioxide is 0.2-2.0 μm; more preferably, it is 0.2-0.8 μm.

[0076] In one specific embodiment, the modifier is selected from any one or two or more of the following: hexadecyltrimethylammonium bromide (CTAB), polyvinyl alcohol (PVA), polyvinyl butyral, medium molecular weight polyethylene (PE), phthalate, aliphatic diester, fatty acid ester, polyphenol ester, polyol ester, epoxy hydrocarbon, and alkyl sulfonate.

[0077] Preferably, the modifier is polyvinyl alcohol or polyvinyl butyral;

[0078] More preferably, the modifier is polyvinyl alcohol, and the dynamic viscosity of polyvinyl alcohol is 5-120 mPa·s, for example, it can be 5 mPa·s, 15 mPa·s, 20 mPa·s, 25 mPa·s, 30 mPa·s, 35 mPa·s, 40 mPa·s, 50 mPa·s, 60 mPa·s, 70 mPa·s, 80 mPa·s, 90 mPa·s, 100 mPa·s, 110 mPa·s, 120 mPa·s, etc.

[0079] Secondly, this application provides a method for preparing a passive cooling fiber material, comprising:

[0080] High-refractive-index inorganic micro / nano particles, modifiers, and polymer substrates are mixed in a weight ratio to prepare composite material masterbatch.

[0081] The composite masterbatch is compounded and extruded in a spinning assembly, and then wound to obtain a passive cooling fiber material.

[0082] In one specific embodiment, high-refractive-index inorganic micro / nano particles, a modifier, and a polymer substrate are blended and melt-extruded in a predetermined ratio to obtain a preliminary optical metamaterial masterbatch; the preliminary optical metamaterial masterbatch is then subjected to a secondary melt-extruded process to obtain a final optical metamaterial masterbatch.

[0083] The optical metamaterial masterbatch is heated and melted, then extruded through a spinneret, cooled and solidified in air to form fibers, which are then wound to obtain nascent optical metamaterial filaments.

[0084] Optical metamaterial filaments are obtained by repeatedly heating, stretching, heat-setting, and winding nascent optical metamaterial filaments along the filament direction; or

[0085] Passive cooling fiber materials are produced by heating, curling, and cutting optical metamaterial filaments.

[0086] Passive cooling fiber materials include filaments and staple fibers.

[0087] Among them, the refractive index of high refractive index inorganic micro-nano particles in the solar irradiation band (0.3-2.5μm) needs to be higher than that of polymer substrate (generally 1.3 to 1.65), with a range of 1.0≤Δn≤11.0, and a preferred range of 2.0≤Δn≤6.0.

[0088] In one specific embodiment, high-refractive-index inorganic micro / nano particles are dispersed in different aggregation states within the passive cooling fiber material, accounting for 0.5%-30% of the passive cooling fiber material by mass, for example, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.; preferably, the high-refractive-index inorganic micro / nano particles account for 2.0%-20% of the passive cooling fiber material by mass; more preferably, 5.0%-20%.

[0089] In one specific embodiment, the particle size of the high-refractive-index inorganic micro / nanoparticles is 0.02-5 μm, for example, it can be 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2... The particle size can be 0.8μm, 3.0μm, 3.2μm, 3.4μm, 3.6μm, 3.8μm, 4.0μm, 4.2μm, 4.4μm, 4.6μm, 4.8μm, 5.0μm, etc.; preferably, the particle size of the high refractive index inorganic micro / nano particles is 0.2-2.0μm, for example, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1.0μm, 1.2μm, 1.4μm, 1.6μm, 1.8μm, 2.0μm, etc.; more preferably, it is 0.2-0.8μm.

[0090] In one specific embodiment, the high refractive index inorganic micro / nanoparticles are selected from any one or two or more of titanium dioxide, zinc sulfide, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, hexagonal boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, and calcium sulfate.

[0091] Preferably, the high-refractive-index inorganic micro / nano particles are titanium dioxide or zinc oxide; more preferably, the high-refractive-index inorganic micro / nano particles are titanium dioxide, wherein the particle size of titanium dioxide is 0.02-5 μm; preferably, the particle size of titanium dioxide is 0.2-2.0 μm; more preferably, it is 0.2-0.8 μm.

[0092] In one specific embodiment, the diameter of the passive cooling fiber material ranges from 10μm to 80μm, preferably from 10 to 30μm, and more preferably from 10 to 20μm.

[0093] In one specific embodiment, the modifier is selected from any one or more of the following: cetyltrimethylammonium bromide (CTAB), polyvinyl alcohol (PVA, preferably a type with low dynamic viscosity: ranging from 5 to 120 mPa·s), polyvinyl butyral (PVB, preferably a type with low dynamic viscosity: ranging from 5 to 120 mPa·s), medium molecular weight polyethylene (PE), phthalates, aliphatic diesters, fatty acid esters, polyphenolic esters, polyol esters, epoxy hydrocarbons, and alkyl sulfonates.

[0094] Preferably, the modifier is polyvinyl alcohol or polyvinyl butyral;

[0095] More preferably, the modifier is polyvinyl alcohol, and the dynamic viscosity of polyvinyl alcohol is 5-120 mPa·s, for example, it can be 5 mPa·s, 15 mPa·s, 20 mPa·s, 25 mPa·s, 30 mPa·s, 35 mPa·s, 40 mPa·s, 50 mPa·s, 60 mPa·s, 70 mPa·s, 80 mPa·s, 90 mPa·s, 100 mPa·s, 110 mPa·s, 120 mPa·s, etc.;

[0096] Preferably, the modifier is uniformly dispersed in the passive cooling fiber material, accounting for 0%-15% of the mass fraction of the passive cooling fiber material, for example, it can be 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10%, 11%, 12%, 13%, 14%, 15%, etc.; preferably, the modifier accounts for 0.2%-2.0% of the mass fraction of the passive cooling fiber material; more preferably, it is 1.0%-2.0%.

[0097] In one specific embodiment, the polymer substrate material is selected from any one or more of polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polylactic acid (PLA), polyolefin, polycarbonate (PC), polyphenylene sulfide (PPS), polyoxymethylene, and polyethylene (PO). Preferably, the polymer substrate material is polyethylene terephthalate (PET) or polylactic acid (PLA).

[0098] Preferably, the polymer substrate material is polyethylene terephthalate (PET) or polylactic acid (PLA).

[0099] In one specific embodiment, the winding speed is 150m / min to 1100m / min.

[0100] In one specific embodiment, the heating and stretching of the initial growth filament specifically includes: the initial growth filament sequentially passes through a first heating roller and a second heating roller along the filament direction and is stretched, wherein the temperature of the first heating roller is 70-120°C, the temperature of the second heating roller is 110-150°C, the speed of the initial growth filament passing through the first heating roller is 130-200 m / min, the speed of the initial growth filament passing through the second heating roller is 650-750 m / min; and the stretching ratio is 1-10 times.

[0101] In one specific embodiment, the composite material masterbatch is prepared into a passive cooling fiber material by using one or more of the following methods: melt spinning, wet spinning, hot drawing, electrospinning, and meltblown spinning, preferably melt spinning or hot drawing.

[0102] Thirdly, this application also provides a passive cooling fiber material fabric. The passive cooling fiber material prepared using the method described above is then subjected to spinning, weaving, and heat setting processes.

[0103] Example

[0104] To better illustrate the technical solution and advantages of this application, the following will provide further details with reference to specific embodiments. Process parameters, raw materials, etc., not described in detail in this application, are all handled using conventional techniques in the field.

[0105] In the following embodiments, the emissivity of melt-spun passively cooled optical metamaterial fabrics in the solar radiation (0.3-2.5 μm) band was tested using a UV-VIS-NIR spectrophotometer combined with an integrating sphere; the morphology of the passively cooled fiber material and yarn was tested using a scanning electron microscope. The names and sources of the raw materials in the following embodiments are as follows:

[0106] Polyethylene terephthalate (purchased from Guangdong Taibao Polymer Co., Ltd., model RAMAPET HVL3012)

[0107] Titanium dioxide nanoparticles (purchased from Shanghai Liangjiang Titanium Dioxide Chemical Products Co., Ltd.)

[0108] Polyvinyl alcohol (purchased from Kuraray International Trading (Shanghai) Co., Ltd.)

[0109] Polyvinyl butyral (purchased from Kuraray International Trading (Shanghai) Co., Ltd.)

[0110] Example 1

[0111] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0112] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 32g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol and titanium dioxide was 2.0%.

[0113] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0114] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0115] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0116] Example 2

[0117] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0118] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 80g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a cutting machine for pelletizing to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 2.0%, and the mass fraction of titanium dioxide was 5.0%.

[0119] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0120] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0121] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0122] Example 3

[0123] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0124] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 48g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a cutting machine for pelletizing to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 3.0%, and the mass fraction of titanium dioxide was 20.0%.

[0125] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0126] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0127] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0128] Example 4

[0129] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0130] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 2.0%, and the mass fraction of titanium dioxide was 20.0%.

[0131] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0132] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0133] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0134] Example 5

[0135] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0136] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 16g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a cutting machine for pelletizing to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 1.0%, and the mass fraction of titanium dioxide was 20.0%.

[0137] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0138] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0139] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0140] Example 6

[0141] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0142] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 3.2g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0143] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0144] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0145] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0146] Example 7

[0147] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0148] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 480g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 2.0%, and the mass fraction of titanium dioxide was 30.0%.

[0149] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0150] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0151] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0152] The performance results of the fabrics in Examples 1 to 7 are shown in Table 1 below.

[0153] Table 1. Properties of fibers, yarns, and fabrics in Examples 1-7

[0154]

[0155] *The percentages for polyvinyl alcohol and titanium dioxide are their mass ratios to the polymer substrate.

[0156] Comparative analysis showed that the fiber, yarn, and fabric obtained using the polyvinyl alcohol and titanium dioxide content in Example 4 exhibited the best mechanical properties and reflectivity. Therefore, it was selected as the optimal control process and used in subsequent examples. A comparison of Examples 1, 2, 4, and 7 revealed that under a fixed polyvinyl alcohol content, as the titanium dioxide content increased, the breaking strength of the fiber, yarn, and fabric decreased to some extent, while the reflectivity in the solar light band gradually increased. This is because the increased concentration of titanium dioxide affects the interaction forces between polymers within the fiber, but simultaneously increases solar scattering on the fiber surface and within the fiber. However, when the titanium dioxide content reached 30%, the excessively high titanium dioxide content resulted in fibers with too low strength, making spinning and weaving difficult. A comparison of Examples 3-6 showed that under a fixed titanium dioxide concentration, as the polyvinyl alcohol content decreased, the fiber breaking strength initially increased and then decreased. This is because a polyvinyl alcohol content of 3.0% is too high, excessively weakening the interaction forces between polymers while improving titanium dioxide dispersibility, and reducing the overall titanium dioxide content in the fiber. When the polyvinyl alcohol content is 0.2%, the content is too low and the effect on improving the dispersion of titanium dioxide in the fiber is not obvious, resulting in a large amount of titanium dioxide agglomeration, which has a negative impact on the mechanical properties and reflectivity of the fiber, yarn and fabric.

[0157] Example 8

[0158] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0159] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.03μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0160] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0161] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0162] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0163] Example 9

[0164] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0165] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.05μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a cutting machine for pelletizing to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0166] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0167] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0168] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0169] Example 10

[0170] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0171] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.2μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0172] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0173] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0174] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0175] Example 11

[0176] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0177] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (0.5μm particle size), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0178] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0179] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0180] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0181] Example 12

[0182] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0183] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 0.8μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a cutting machine for pelletizing to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0184] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0185] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0186] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0187] Example 13

[0188] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0189] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 1.0μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0190] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0191] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0192] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0193] Example 14

[0194] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0195] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 1.2μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0196] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0197] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0198] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0199] Example 15

[0200] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0201] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 2.0μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a cutting machine for pelletizing to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0202] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0203] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0204] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0205] Example 16

[0206] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0207] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl alcohol, 320g of titanium dioxide (particle size 5.0μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl alcohol was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0208] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0209] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0210] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0211] Table 2 Properties of fibers, yarns, and fabrics with different titanium dioxide particle sizes

[0212]

[0213]

[0214] Comparative studies showed that as the titanium dioxide particle size increased from 0.03 μm to 5 μm, the mechanical strength and reflectivity of the fibers, yarns, and fabrics initially increased and then decreased. This is because when the titanium dioxide nanoparticles are too small (as in Example 8), they tend to agglomerate, affecting their mechanical properties and reflectivity. However, when the particle size is too large (as in Example 16), it significantly impacts the interaction forces between polymers within the fiber, creating mechanical property defects and severely reducing mechanical properties, making normal spinning impossible. Specifically, the reflectivity in the solar radiation band was best when the titanium dioxide particle size ranged from 0.2 to 0.8 μm, with the best effect observed when the particle size was 0.4 μm.

[0215] Example 17

[0216] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0217] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl butyral, 32g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fractions of polyvinyl butyral and titanium dioxide were 2.0%.

[0218] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0219] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0220] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0221] Example 18

[0222] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0223] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl butyral, 80g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl butyral was 2.0%, and the mass fraction of titanium dioxide was 5.0%.

[0224] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0225] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0226] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0227] Example 19

[0228] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0229] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 48g of the dried polyvinyl butyral, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl butyral was 3.0%, and the mass fraction of titanium dioxide was 20.0%.

[0230] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0231] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0232] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0233] Example 20

[0234] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0235] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl butyral, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl butyral was 2.0%, and the mass fraction of titanium dioxide was 20.0%.

[0236] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0237] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0238] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0239] Example 21

[0240] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0241] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 16g of the dried polyvinyl butyral, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl butyral was 1.0%, and the mass fraction of titanium dioxide was 20.0%.

[0242] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0243] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0244] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0245] Example 22

[0246] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0247] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 3.2g of the dried polyvinyl butyral, 320g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl butyral was 0.2%, and the mass fraction of titanium dioxide was 20.0%.

[0248] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0249] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0250] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0251] Example 23

[0252] This application provides a method for preparing a passive cooling fiber material, including the following steps:

[0253] 1600g of polyethylene terephthalate was weighed and vacuum dried at 130℃ for 24h. 32g of the dried polyvinyl butyral, 480g of titanium dioxide (particle size 0.4μm), and polyethylene terephthalate were then fed into a twin-screw extruder and melt-extruded at 265℃. After water cooling and drying, the mixture was fed into a pelletizer to obtain a composite modified masterbatch. The composite modified masterbatch was placed in a ventilated environment for 6h and then dried in a vacuum oven at 130℃ for 24h. The mass fraction of polyvinyl butyral was 2.0%, and the mass fraction of titanium dioxide was 30.0%.

[0254] The dried composite modified masterbatch is added to the feed inlet of a melt spinning machine, heated and melted at 285°C and extruded through the spinneret, and the initial grown filament is obtained at a winding speed of 1000 m / min.

[0255] The nascent filaments are first washed in a water bath at a speed of 15 m / min. Then, they are heated and drawn along the filament direction, sequentially passing through a first heating roller (90°C) and a second heating roller (130°C). The nascent filaments pass through the first heating roller at a speed of 40 m / min and through the second heating roller at a speed of 50 m / min, resulting in heating and drawing ratios of 2.6 times and 1.25 times, respectively. This yields a passively cooled fiber material with a fiber diameter of 12 μm.

[0256] This embodiment also provides a passive cooling optical metamaterial fabric, which is obtained by spinning the above-mentioned passive cooling fiber material and then weaving the yarn through warp and weft.

[0257] The performance results of the fabrics in Examples 17-23 are shown in Table 3 below.

[0258] Table 3 Properties of medium-fiber, yarn and fabric after the reaction of polyvinyl butyral with titanium dioxide.

[0259]

[0260] In comparison, using polyvinyl butyral as a modifier resulted in similar trends in the mechanical properties and solar radiation bands of fibers, yarns, and fabrics as when polyvinyl alcohol was used as a modifier (Examples 1-7). However, in terms of mechanical strength and reflectivity data for fibers, yarns, and fabrics, polyvinyl alcohol was superior to polyvinyl butyral.

[0261] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A passive cooling fiber material, comprising high refractive index inorganic micro / nano particles, a modifier, and a polymer substrate material; The high-refractive-index inorganic micro / nano particles have a particle size of 0.02-5 μm, the polymer substrate material is polyethylene terephthalate (PET), and the modifier is selected from any one or two of polyvinyl alcohol (PVA) and polyvinyl butyral. The mass ratio of the modifier to the high-refractive-index inorganic micro / nano particles is 1:1 to 1:100; The high-refractive-index inorganic micro / nano particles account for 0.5%-30% of the mass fraction of the passive cooling fiber material; The modifier accounts for 0%-15% of the mass fraction of the passive cooling fiber material.

2. The passive cooling fiber material according to claim 1, wherein the high refractive index inorganic micro / nano particles have a particle size of 0.2-2.0 μm.

3. The passive cooling fiber material according to claim 1, wherein, The diameter range of the passive cooling fiber material is 10μm-80μm.

4. The passive cooling fiber material according to claim 1, wherein, The high-refractive-index inorganic micro / nanoparticles are selected from any one or two or more of titanium dioxide, zinc sulfide, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, hexagonal boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, and calcium sulfate.

5. The passive cooling fiber material according to claim 1, wherein, The mass ratio of the modifier to the high-refractive-index inorganic micro / nanoparticles is 1:2.5-1:

10.

6. The passive cooling fiber material according to claim 1, wherein, The mass ratio of the modifier to the high-refractive-index inorganic micro / nanoparticles is 1:6.7-1:

10.

7. The passive cooling fiber material according to claim 1, wherein, The high-refractive-index inorganic micro / nano particles account for 2.0%-20% of the mass fraction of the passive cooling fiber material.

8. The passive cooling fiber material according to claim 1, wherein, The high-refractive-index inorganic micro / nano particles account for 5.0%-20% of the mass fraction of the passive cooling fiber material.

9. The passive cooling fiber material according to claim 1, wherein, The modifier accounts for 0.2%-2.0% of the mass fraction of the passive cooling fiber material.

10. The passive cooling fiber material according to claim 1, wherein, The modifier accounts for 1.0%-2.0% of the mass fraction of the passive cooling fiber material.

11. The passive cooling fiber material according to claim 1, wherein the high refractive index inorganic micro / nano particles have a particle size of 0.2-0.8 μm.

12. The passive cooling fiber material according to claim 1, wherein, The diameter range of the passive cooling fiber material is 10-30 μm.

13. The passive cooling fiber material according to claim 1, wherein, The diameter range of the passive cooling fiber material is 10-20 μm.

14. The passive cooling fiber material according to claim 1, wherein, The high-refractive-index inorganic micro / nano particles are titanium dioxide or zinc oxide.

15. The passive cooling fiber material according to claim 1, wherein, The modifier is polyvinyl alcohol, and the dynamic viscosity of the polyvinyl alcohol is 5-120 mPa·s.

16. A method for preparing the passive cooling fiber material of claim 1, comprising: High-refractive-index inorganic micro / nano particles, modifiers, and polymer substrates are mixed in a weight ratio to prepare composite material masterbatch. The composite masterbatch is compounded and extruded in a spinning assembly, and then wound to obtain a passive cooling fiber material. The high-refractive-index inorganic micro / nano particles have a particle size of 0.02-5 μm, the polymer substrate material is polyethylene terephthalate (PET), and the modifier is selected from any one or two of polyvinyl alcohol (PVA) and polyvinyl butyral. The mass ratio of the modifier to the high-refractive-index inorganic micro / nano particles is 1:1 to 1:100; The high-refractive-index inorganic micro / nano particles account for 0.5%-30% of the mass fraction of the passive cooling fiber material; The modifier accounts for 0%-15% of the mass fraction of the passive cooling fiber material.

17. The method according to claim 16, wherein, The high-refractive-index inorganic micro / nano particles have a particle size of 0.2-2.0 μm. The mass ratio of the modifier to the high-refractive-index inorganic micro / nano particles is 1:2.5-1:10; The high-refractive-index inorganic micro / nano particles account for 2.0%-20% of the mass fraction of the passive cooling fiber material; The modifier accounts for 0.2%-2.0% of the mass fraction of the passive cooling fiber material.

18. The method according to claim 16, wherein, The high-refractive-index inorganic micro / nano particles have a particle size of 0.2-0.8 μm.

19. The method of claim 16, wherein, The diameter range of the passive cooling fiber material is 10μm-80μm.

20. The method according to any one of claims 16-19, wherein, The high-refractive-index inorganic micro / nanoparticles are selected from any one or two or more of titanium dioxide, zinc sulfide, silicon dioxide, silicon carbide, silicon nitride, zinc oxide, hexagonal boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, and calcium sulfate.

21. The method according to any one of claims 16-19, wherein the composite material masterbatch is prepared into the passive cooling fiber material using one or more of the methods selected from melt spinning, wet spinning, hot drawing, electrospinning, and meltblown spinning.

22. The method according to claim 21, wherein, The passive cooling fiber material is a filament and / or a short fiber.

23. The method according to claim 16, wherein, The mass ratio of the modifier to the high-refractive-index inorganic micro / nanoparticles is 1:6.7-1:

10.

24. The method of claim 16, wherein, The high-refractive-index inorganic micro / nano particles account for 5.0%-20% of the mass fraction of the passive cooling fiber material.

25. The method according to claim 16, wherein, The modifier accounts for 1.0%-2.0% of the mass fraction of the passive cooling fiber material.

26. The method of claim 16, wherein, The diameter range of the passive cooling fiber material is 10-30 μm.

27. The method according to claim 16, wherein, The diameter range of the passive cooling fiber material is 10-20 μm.

28. The method according to any one of claims 16-19, wherein, The high-refractive-index inorganic micro / nano particles are titanium dioxide or zinc oxide.

29. The method according to any one of claims 16-19, wherein, The modifier is polyvinyl alcohol, and the dynamic viscosity of the polyvinyl alcohol is 5-120 mPa·s.

30. The method according to any one of claims 16-19, wherein the composite material masterbatch is prepared into the passive cooling fiber material by melt spinning or hot drawing.

31. A passive cooling fiber material fabric, wherein, The passive cooling fiber material prepared by any one of claims 16 to 30 is obtained by spinning, weaving, heat setting and other processes.

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