A metamaterial spunbond fabric and preparation method thereof

Abstract

The present application discloses a metamaterial spunbond fabric and a method for preparing the same. The metamaterial spunbond fabric comprises at least one single-layer fiber spunbond layer, the single-layer fiber spunbond layer comprising metamaterial fibers, the metamaterial fibers being interwoven and stacked to form pores. Among the pores, pores with a diameter of 100-3000 nm are reflective pores, and the total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond fabric. The metamaterial fibers are formed from a composite material comprising a polymer base material and micro-nanoparticles, and the average particle size of the micro-nanoparticles is 100-3000 nm. The metamaterial fibers are interwoven and arranged with the micro-nanoparticles randomly arranged within the fibers, forming a spunbond fabric with metamaterial properties. Based on this photonic design, an ultra-wideband optical response of 0.3-2.5 μm and 8-13 μm is generated, thereby achieving guidance and manipulation of solar radiation and human infrared thermal radiation, and photothermal regulation of the microenvironmental temperature of the fabric and human skin to achieve efficient thermal management.

Description

Technical Field

[0001] The present application relates to the field of material manufacturing technology, and in particular to a metamaterial spunbond fabric and a preparation method thereof. Background Art

[0002] With the development of science and technology and the improvement of living standards, people's requirements for textiles have become more diversified, and various functional materials have been applied. Among them, functional materials have attracted more and more attention and love because they can improve human comfort.

[0003] Outdoor activities and work often expose people to harmful sunlight, which can cause skin burns, heatstroke, and other health issues. Consequently, more and more protective equipment is being used for outdoor protection. Many current protective products typically feature multi-layer film structures, including a reflective layer made of a material with high reflectivity within the sunlight spectrum and a radiant layer made of a material with high emissivity at the atmospheric window.

[0004] Since the multi-layer membrane structure has poor air permeability, directly attaching it to fabrics that come into contact with the human body will reduce the heat dissipation achieved by the human body through air circulation, thus limiting human comfort. Summary of the Invention

[0005] In order to solve the above problems, the present application provides a metamaterial spunbond fabric and a preparation method thereof. By designing the internal microstructure of the fiber and the microstructure between fibers, a metamaterial spunbond fabric is produced to achieve effective regulation of electromagnetic waves, while achieving full reflection effect of the entire sunlight band, thereby realizing personal protection function.

[0006] The specific technical solutions of this application are as follows:

[0007] 1. A metamaterial spunbond fabric, characterized in that:

[0008] The metamaterial spunbond fabric comprises at least one single-layer fiber spunbond layer, wherein the single-layer fiber spunbond layer comprises metamaterial fibers, and the metamaterial fibers are interwoven and overlapped to form pores;

[0009] Among the pores, pores with a diameter of 100-3000 nm are reflective pores, and the total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond fabric;

[0010] The metamaterial fiber is formed of a composite material including a polymer base material and micro-nano particles, and the average particle size of the micro-nano particles is 100-3000 nm.

[0011] 2. The metamaterial spunbond fabric according to item 1 is characterized in that the polymer base material has high emissivity in the atmospheric window band.

[0012] 3. The metamaterial spunbond fabric according to item 1 or 2, wherein among the pores, pores with a diameter of 100-1000 nm are reflective pores, and the total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond fabric;

[0013] Preferably, among the pores, pores with a diameter of 300-900 nm are reflective pores, and the total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond fabric;

[0014] More preferably, among the pores, pores with a diameter of 400-700 nm are reflective pores, and the total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond fabric.

[0015] 4. The metamaterial spunbond fabric according to any one of items 1 to 3, wherein the total volume of the reflective pores accounts for 50% to 85% of the volume of the spunbond fabric.

[0016] 5. The metamaterial spunbond fabric according to any one of items 1 to 4, wherein the diameter of the metamaterial fiber is 2-40 μm, and the spunbond fabric has a gram weight of 10-40 g / m 2 .

[0017] 6. The metamaterial spunbond fabric according to any one of items 1 to 5, characterized in that the average particle size of the micro-nano particles is 400-700 nm.

[0018] 7. The metamaterial spunbond fabric according to any one of items 1 to 6, characterized in that the refractive index of the micro-nanoparticles in the solar radiation band is higher than the refractive index of the polymer base material in the solar radiation band.

[0019] 8. The metamaterial spunbond fabric according to any one of items 1 to 7, characterized in that the micro-nano particles are selected from titanium dioxide (TiO2), zinc sulfide (ZnS), silicon carbide (SiC), silicon nitride (Si3N4), zinc oxide (ZnO), boron nitride (BN), aluminum silicate (Al2SiO 5) , any one or more of barium sulfate (BaSO4), calcium carbonate (CaCO3), magnesium oxide (MgO), aluminum oxide (Al2O3), magnesium carbonate (MgCO3), barium carbonate (BaCO3) and calcium sulfate (CaSO4).

[0020] 9. The metamaterial spunbond fabric according to any one of items 1 to 8, characterized in that the polymer base material comprises an organic polymer material containing any one or more of CF, C=O, -CH3, -CH, C–O and C–C functional groups.

[0021] 10. The metamaterial spunbond fabric according to any one of items 1 to 9, characterized in that the polymer base material is selected from any one or more of polymethyl methacrylate (PMMA), fluororesin, polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polystyrene (PS), polyester and sodium isophthalate sulfonate copolymer, acrylate copolymer, polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), polyvinylidene chloride resin (PVDC), vinyl acetate resin, polyvinyl alcohol (PVA), polylactic acid (PLA), polyurethane (PU), polyacrylonitrile (PAN), cycloolefin copolymer (COC), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), styrene dimethyl methacrylate copolymer (SMMA), polyoxymethylene (POM), polyphenylene ether (PPO), polyimide (PI), vinyl acetate resin, polyvinyl formal, polyvinyl acetate (PVAC) and polyvinyl acetal.

[0022] 11. The metamaterial spunbond fabric according to any one of items 1 to 10, characterized in that the difference between the refractive index of the polymer base material and the refractive index of the micro-nanoparticles is greater than 0.6.

[0023] 12. The metamaterial spunbond fabric according to any one of items 1 to 11, characterized in that the mass of the micro-nanoparticles is 5%-40% of the mass of the polymer base material.

[0024] 13. The metamaterial spunbond fabric according to any one of items 1 to 12, characterized in that the metamaterial spunbond fabric comprises N single-layer fiber spunbond layers, wherein the N single-layer fiber spunbond layers are stacked, and N ≥ 2;

[0025] Preferably, N is 5-2500.

[0026] 14. The metamaterial spunbond fabric according to any one of items 1 to 13, wherein the metamaterial spunbond fabric has a thickness of 0.1-1.5 mm.

[0027] 15. The metamaterial spunbond fabric according to item 13, characterized in that, when N ≥ 2, the mass percentage of the micro-nanoparticles in each of the N single fiber spunbond layers to the mass percentage of the polymer base material in the layer is not completely the same or completely different;

[0028] Preferably, the percentage of the total volume of the reflective voids in each layer to the volume of the single fiber spunbond layer is not completely the same or completely different.

[0029] 16. A method for preparing a metamaterial spunbond fabric, characterized in that the preparation method comprises:

[0030] Mixing a polymer base material and micro-nano particles to form a full-spectrum reflective composite material, wherein the average particle size of the micro-nano particles is 100-3000 nm;

[0031] Spraying the full-spectrum reflective composite material through a melt-blowing die to form a melt stream;

[0032] The melt stream meets the high-speed hot air flow at the outlet of the meltblowing die head, and the melt stream is stretched and refined by the high-speed hot air flow, and spun to obtain metamaterial fibers. The metamaterial fibers fall evenly on the roller of the receiving device, and the number of turns of the roller is controlled to form a metamaterial spunbond fabric.

[0033] 17. The preparation method according to item 16 is characterized in that the spinning temperature of the melt stream is 170-300°C, and the temperature of the high-speed hot air flow is 160-485°C.

[0034] 18. The preparation method according to item 16 or 17 is characterized in that the receiving distance is 30-70 cm and the winding speed of the rolling roller is 5-45 m / min.

[0035] 19. The preparation method according to any one of items 16 to 18 is characterized in that the number of turns N of the rolling roller is controlled to obtain the metamaterial spunbond fabric comprising N single-layer fiber spunbond layers.

[0036] 20. The preparation method according to any one of items 16 to 19 is characterized in that after forming the metamaterial spunbond fabric, the method further comprises using a hot rolling mill to perform hot rolling bonding and reinforcement on the metamaterial spunbond fabric, the hot rolling temperature of the hot rolling mill is 30-150°C, and the winding speed of the hot rolling mill is 4-60m / min.

[0037] 21. A metamaterial spunbond fabric prepared by the method for preparing a metamaterial spunbond fabric according to any one of items 16 to 20.

[0038] Effects of the Invention

[0039] The metamaterial fibers contained in the single-layer spunbond layer of the metamaterial spunbond fabric of the present application are formed from a composite material comprising a polymer base material and micro-nanoparticles. The polymer base material has a high emissivity in the atmospheric window band (8-13μm), which can transmit heat from an object through the atmosphere's infrared window to the cold universe in the form of electromagnetic waves. Because the micro-nanoparticles act as a random scattering medium and are uniformly distributed within the polymer base material, with an average particle size of 100-3000nm, similar to the wavelength of solar radiation, a microstructure with high scattering efficiency for solar radiation can be formed within the fiber, enhancing the metamaterial fiber's reflective properties for the solar radiation band (0.3-2.5μm).

[0040] At the same time, the reflective pores in the metamaterial spunbond fabric of the present application are formed by the interweaving and overlapping of metamaterial fibers. The total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond fabric. At this time, the reflective pores can also be regarded as random scattering media uniformly distributed inside the spunbond fabric. Since the refractive index of the high-emissivity polymer base material is between 1.4-1.6 and the refractive index of air is 1. Therefore, there is a large refractive index difference between the polymer base material and air, and the diameter of the reflective pores is 100-3000nm, which is similar to the wavelength of solar radiation. A microstructure with high scattering efficiency for solar radiation can be formed between the fibers, thereby regulating the external optical properties of the fibers and enhancing the reflective properties of the metamaterial spunbond fabric.

[0041] The metamaterial fibers of the present application are interwoven and arranged with random arrangement of micro-nanoparticles inside the fibers, forming a spunbond fabric with metamaterial properties. Based on this photonic design, an ultra-wideband optical response of 0.3-2.5μm and 8-13μm is generated, thereby achieving the guidance and manipulation of solar radiation and human infrared thermal radiation, and photothermally regulating the microenvironment temperature of the spunbond fabric and human skin to achieve efficient thermal management. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic structural diagram of a metamaterial spunbond fabric according to a specific embodiment of the present application;

[0043] Figure 2 Schematic diagram of the structure of a metamaterial fiber according to a specific embodiment of the present application;

[0044] Figure 3 It is a schematic structural diagram of a metamaterial fiber according to another specific embodiment of the present application. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of this application more clear, the following will further describe the embodiments of this application in detail with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0046] With the continuous deepening of research on optical materials and the rapid expansion of their technological applications, new physical concepts and methods for light field manipulation have emerged, providing a solid foundation for research and application in physics, information processing, communications, materials, and new energy. Metamaterials are a class of artificial materials with unique properties. Through periodic microstructures such as photonic crystals, they can effectively manipulate electromagnetic waves, thereby confining light along the extension of optical fibers. Their transmission band can be controlled based on the fiber's structural design and material selection.

[0047] This application utilizes the principle of metamaterial properties to regulate the microstructure of fibers to form textiles with changed infrared radiation characteristics, thereby achieving wide-spectrum selective regulation in infinite external space, which has great advantages in the field of infrared radiation regulation.

[0048] The present application provides a metamaterial spunbond fabric, such as Figure 1 As shown, the metamaterial spunbond fabric includes at least one single fiber spunbond layer, the single fiber spunbond layer includes metamaterial fibers 10, and the metamaterial fibers 10 are interwoven and stacked to form pores. Among the pores, the pores with a diameter of 100-3000 nm are reflective pores 30, and the total volume of the reflective pores 30 accounts for 10%-90% of the volume of the spunbond fabric; Figure 2 As shown, the metamaterial fiber 10 is formed of a composite material including a polymer base material 11 and micro-nano particles 12 , and the average particle size of the micro-nano particles 12 is 100-3000 nm.

[0049] In one specific embodiment, the polymer substrate material has a high emissivity in the atmospheric window band (8-13μm), allowing heat from an object to be transmitted to the cold universe via electromagnetic waves through the atmosphere's infrared window. Because the micro-nanoparticles, acting as a random scattering medium, are uniformly distributed within the polymer substrate, with an average particle size of 100-3000nm, similar to the wavelength of solar radiation, a microstructure with high scattering efficiency for solar radiation is formed within the fiber, enhancing the metamaterial fiber's reflective properties for solar radiation in the 0.3-2.5μm wavelength band.

[0050] The reflective pores in the spunbond fabric of the present application are formed by the interweaving and overlapping of metamaterial fibers. The diameter of the reflective pores is 100-3000nm, and the total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond fabric. At this time, the reflective pores can also be regarded as random scattering media uniformly distributed inside the spunbond fabric. Since the refractive index of the high-emissivity polymer base material is between 1.4-1.6 and the refractive index of air is 1. Therefore, there is a large refractive index difference between the polymer base material and the air, and the diameter of the reflective pores is 100-3000nm, which is similar to the size of the spectral wavelength. A microstructure with high scattering efficiency for solar radiation can be formed between the fibers, thereby regulating the external optical properties of the fibers and enhancing the reflective properties of the metamaterial spunbond fabric.

[0051] The metamaterial fibers are interwoven and arranged with random arrangement of micro-nanoparticles inside the fibers, forming a spunbond fabric with metamaterial properties. Based on this photonic design, an ultra-wideband optical response of 0.3-2.5μm and 8-13μm is generated, thereby guiding and manipulating solar radiation and human infrared thermal radiation, and photothermally regulating the microenvironment temperature of the spunbond fabric and human skin to achieve efficient thermal management.

[0052] In a specific embodiment, the single-layer fiber spunbond layer is composed of metamaterial fibers, and the metamaterial fibers are interwoven and stacked to form pores.

[0053] In a specific embodiment, the metamaterial fiber is formed of a polymer base material and micro-nanoparticles.

[0054] It is understood that the pores of the present application are polygonal pores formed by cross-stacked three or more full-spectrum reflective fibers, and the pore diameter can be the diameter of the circumscribed circle of the polygon. Matching the pore diameter with the wavelength of the solar radiation band can enhance the reflective properties of the metamaterial spunbond fabric. Therefore, the diameter of the reflective pore is 100-3000nm. In a specific embodiment, the diameter of the reflective pore can be 200-1000nm, for example, 200nm, 210nm, 230nm, 250nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 950nm, 970nm, 990nm, 1000nm, etc. Preferably, the diameter of the reflective pore is 400-700nm, and most preferably 500nm.

[0055] In a specific embodiment, the total volume of the reflective pores may account for a percentage of the volume of the spunbond fabric of, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc. Since reflective pores can be used to enhance the reflective properties of the metamaterial spunbond fabric, but too many reflective pores will affect the strength of the spunbond fabric, the total volume of the reflective pores preferably accounts for 50%-85% of the volume of the spunbond fabric.

[0056] Specifically, a scanning electron microscope (SEM) can be used to capture an image, and the pores that meet the diameter requirements can be counted from the image. The sum of the reflective pore volumes of each single fiber spunbond layer can be calculated, and then divided by the total volume of the metamaterial spunbond fabric to obtain the ratio of the total volume of the reflective pores to the volume of the spunbond fabric. In this application, the total volume of the metamaterial spunbond fabric is the sum of the volume of all fibers constituting the metamaterial spunbond fabric and the volume of all pores formed by all fibers.

[0057] In a specific embodiment, the diameter of the single filament of the metamaterial fiber is 2-40 μm. Exemplarily, the diameter of the single filament of the metamaterial fiber is 2 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, etc.

[0058] Specifically, the pore diameter, the percentage of the total reflective pore volume to the spunbond fabric volume, and the metamaterial fiber diameter and length can all be controlled by adjusting process parameters, which are then determined based on the specific electron microscopy results. For specific process parameters, please refer to the description of the preparation method.

[0059] Preferably, the weight of the metamaterial spunbond fabric is 10-40 g / m 2 For example, the weight of the metamaterial spunbond fabric can be 10 g / m 2 , 20g / m 2 , 30g / m 2 , 40g / m 2 wait.

[0060] In one specific embodiment, the high-emissivity polymer substrate material has an emissivity greater than 85% in the atmospheric window band (8-13 μm), for example, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, etc. Specifically, the high-emissivity polymer substrate material can include an organic polymer material containing any one or more of the following functional groups: CF, C=O, -CH3, -CH, C–O, and C–C. Because the vibrational frequency peaks of these functional groups, CF, C=O, -CH3, -CH, C–O, and C–C, fall within the atmospheric window band (8-13 μm), these polymers exhibit both high emissivity and high absorptivity in the atmospheric window band (8-13 μm).

[0061] In one embodiment, the micro-nano particles are inorganic micro-nano particles with low absorptivity and high refractive index in the solar radiation band (0.3-2.5 μm). The low absorptivity of the micro-nano particles requires that the imaginary part of the refractive index (extinction coefficient) is less than 10 -4 ;The high refractive index of micro-nano particles requires a refractive index of >1.5.

[0062] Optionally, the average particle size of the micro-nano particles is 400-700 nm. Exemplarily, the average particle size of the micro-nano particles is 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, or 700 nm. Preferably, the diameter of the micro-nano particles is 500 nm. The average particle size of the micro-nano particles refers to the average particle size obtained by electron microscopy, specifically the D50 median diameter, for example, the D50 median diameter is obtained by observing 500 particles.

[0063] Furthermore, the mass of the micro-nanoparticles is 5%-40% of the mass of the polymer base material, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc., preferably 30%-40%.

[0064] Specifically, the micro-nano particles can be titanium dioxide (TiO2), zinc sulfide (ZnS), silicon carbide (SiC), silicon nitride (Si3N4), zinc oxide (ZnO), boron nitride (BN), aluminum silicate (Al2SiO 5) , barium sulfate (BaSO4), calcium carbonate (CaCO3), magnesium oxide (MgO), aluminum oxide (Al2O3), magnesium carbonate (MgCO3), barium carbonate (BaCO3), and calcium sulfate (CaSO4), any one or more thereof.

[0065] Specifically, the polymer base material can be any one or more of polymethyl methacrylate (PMMA), fluororesin, polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polystyrene (PS), polyester and sodium isophthalate sulfonate copolymer, acrylate copolymer, polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), polyvinylidene chloride resin (PVDC), vinyl acetate resin, polyvinyl alcohol (PVA), polylactic acid (PLA), polyurethane (PU), polyacrylonitrile (PAN), cycloolefin copolymer (COC), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), styrene dimethyl methacrylate copolymer (SMMA), polyoxymethylene (POM), polyphenylene ether (PPO), polyimide (PI), vinyl acetate resin, polyvinyl formal, polyvinyl acetate (PVAC) and polyvinyl acetal.

[0066] In one embodiment, in order to achieve higher scattering efficiency and improve reflectivity, the difference between the refractive index of the micro-nanoparticles and the refractive index of the polymer base material is as large as possible. Preferably, the difference between the refractive index of the polymer base material and the refractive index of the micro-nanoparticles is greater than 0.6. Exemplarily, the combination of the micro-nanoparticles and the polymer base material can be selected in the following ways:

[0067] Optionally, the micro-nano particles are any one, two or three of titanium dioxide (TiO2), zinc sulfide (ZnS) and silicon carbide (SiC), and the polymer substrate material can be polymethyl methacrylate (PMMA), fluororesin, polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polystyrene (PS), polyester and sodium isophthalate sulfonate copolymer, acrylate copolymer, polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), polyvinylidene chloride, etc. Any one or more of resin (PVDC), vinyl acetate resin, polyvinyl alcohol (PVA), polylactic acid (PLA), polyurethane (PU), polyacrylonitrile (PAN), cycloolefin copolymer (COC), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), styrene dimethyl methacrylate copolymer (SMMA), polyoxymethylene (POM), polyphenylene ether (PPO), polyimide (PI), vinyl acetate resin, polyvinyl formal, polyvinyl acetate (PVAC) and polyvinyl acetal.

[0068] Optionally, the micro-nano particles are silicon nitride (Si3N4), and the polymer base material can be any one or more of polyester and sodium sulfonate isophthalate copolymer, fluororesin, and acrylate copolymer.

[0069] Optionally, the micro-nano particles are zinc oxide (ZnO), and the polymer base material can be a copolymer of polyester and sodium sulfonate isophthalate and / or a fluororesin.

[0070] Optionally, the micro-nanoparticles are boron nitride (BN), and the polymer base material can be any one or more of polymethyl methacrylate (PMMA), polyester and sodium isophthalate sulfonate copolymer, fluororesin, polyurethane (PU), polypropylene (PP), polyvinylidene chloride resin (PVDC), polylactic acid (PLA), polyvinylidene fluoride (PVDF), polyoxymethylene (POM), polyimide (PI), polyvinyl formal, polyphenylene ether (PPO), polyvinyl acetal, and polyvinyl acetate (PVAC).

[0071] Optionally, the micro-nano particles are aluminum silicate (Al2SiO5), and the polymer substrate material can be any one or more of polyacrylonitrile (PAN), polytrimethylene terephthalate (PTT) and polystyrene (PS).

[0072] In one embodiment, Figure 3As shown, the metamaterial spunbond fabric may include N single-layer fiber spunbond layers 10, which are stacked perpendicular to the extension direction (PQ direction) of the fiber spunbond layers, with N ≥ 2. Preferably, N is 5-2500, for example, 2, 3, 5, 6, 7, 8, 9, 10, 20, 100, 500, 1000, 2500, etc. Because the upper layer is stacked with single-layer fiber spunbond layers, the micro-nano particles are randomly distributed in multiple layers perpendicular to the extension direction of the fiber spunbond layers. Therefore, sunlight 20 penetrating the upper metamaterial fibers can be reflected by the micro-nano particles 11 or reflective pores (not shown) in the lower metamaterial fibers 10, thereby enhancing the infrared radiation emissivity and solar radiation reflectivity. The emissivity in the mid-infrared band (8-13 μm) is ≥ 90%, and the reflectivity in the solar radiation band (0.3-2.5 μm) is ≥ 90%, achieving a good full-spectrum reflection effect.

[0073] In a specific embodiment, the metamaterial spunbond fabric has a thickness of 0.1-1.5 mm, for example, 0.1 mm, 0.5 mm, 1.0 mm, 1.5 mm, preferably 0.5-1.5 mm, and more preferably 0.6 mm.

[0074] In a specific embodiment, the metamaterial fiber can be a single circular structure or a skin-core structure; the core layer of the skin-core structure metamaterial fiber is a polymer base material and micro-nano particles, and the skin layer is a polymer base material; the radius ratio of the core layer to the skin layer is 1:9-9:1, preferably 5:5-9:1, and further preferably 8:2; the skin layer wraps the core layer to form a coaxial structure, reducing the risk of inhalation caused by the shedding of particles on the surface of the single-structure metamaterial fiber.

[0075] In a specific embodiment, when the metamaterial spunbond fabric includes two, three, or four or more single-layer fiber spunbond layers, from the inner layer to the outer layer, the mass fraction of the micro-nanoparticles in the polymer base material in each layer (i.e., the particle doping concentration in each single-layer fiber spunbond layer) may be the same, may not be completely the same, or may be completely different, and may further vary in a gradient.

[0076] In a specific embodiment, when the particle doping concentration changes in a gradient from the inner layer to the outer layer, the doping concentration of the inorganic micro-nano particles gradually decreases from the inner layer to the outer layer, and the outer layer may be undoped.

[0077] In a specific embodiment, when the particle doping concentration changes gradiently from the inner layer to the outer layer, the volume fraction of the reflective pores in the spunbond layer in which they are located also changes gradiently from the inner layer to the outer layer. Furthermore, the volume fraction of the reflective pores in the single-layer fiber spunbond layer in the single-layer fiber spunbond layer gradually increases from the inner layer to the outer layer.

[0078] When the outer layer of the metamaterial spunbond fabric is undoped, the undoped single-layer fiber spunbond layer includes pores formed by the interweaving and overlapping of the metamaterial fibers. Pores with a diameter of 100-3000 nm are reflective pores, and the total volume of the reflective pores accounts for 10%-90% of the volume of the spunbond layer. The metamaterial fibers are entirely composed of a polymer base material and do not contain any micro-nanoparticle doping. The total thickness of the outer undoped fiber spunbond layer in the metamaterial spunbond fabric ranges from 30-100 μm.

[0079] The absorption of some inorganic micro-nanoparticles in the ultraviolet (UV) band reduces the reflectivity of solar radiation, while air pores do not absorb UV radiation. When the outer layer is an undoped spunbond layer, it primarily reflects solar radiation in the UV band (300-400nm), enhancing the overall mechanical properties of the metamaterial spunbond fabric. Based on this effect, the thickness of the undoped fiber-doped spunbond layer needs to be limited. A thickness too low (<30μm) will not provide adequate UV reflection, while a thickness too high (>100μm) will enhance absorption in the visible-near-infrared band (400-2500nm). Therefore, the preferred thickness of the undoped spunbond layer is 30-100μm. Compared to fully doped metamaterial spunbond nonwovens, the tensile strength is improved.

[0080] According to a second aspect of the present application, a method for preparing a metamaterial spunbond fabric is provided, the method comprising:

[0081] Step 1: Mixing a polymer base material and micro-nano particles to form a full-spectrum reflective composite material, wherein the average particle size of the micro-nano particles is 100-3000 nm;

[0082] Step 2: ejecting the full-spectrum reflective composite material through a melt-blowing die to form a thin melt stream;

[0083] Step 3: The melt stream meets the high-speed hot air flow at the outlet of the meltblowing die head, and the melt stream is stretched and refined by the high-speed hot air flow, and spun to obtain metamaterial fibers. The metamaterial fibers evenly fall on the roller of the receiving device to form a metamaterial spunbond fabric.

[0084] In one embodiment, after the full spectrum reflective composite material is mixed, it can be cooled for later use. When necessary, the full spectrum reflective composite material is heated to form a melt, and then the operation of step 2 is performed.

[0085] In one embodiment, in step 1, the polymer substrate material has a high emissivity in the atmospheric window band (8-13 μm). Alternatively, the polymer substrate material may include an organic polymer material containing any one or more of the following functional groups: CF, C=O, -CH3, -CH, C–O, and C–C.

[0086] In one embodiment, in step 1, the average particle size of the micro-nano particles may be 100-3000 nm. Preferably, the average particle size of the micro-nano particles is 200-1000 nm, more preferably 400-700 nm. Exemplarily, the diameter of the micro-nano particles is 200 nm, 210 nm, 230 nm, 250 nm, 300 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 800 nm, 900 nm, 950 nm, 970 nm, 990 nm, 1000 nm, etc. Preferably, the average particle size of the micro-nano particles is 500 nm.

[0087] In one embodiment, in step 2, the melt is filtered through a melt filter and then quantitatively extruded through a metering pump. The extruded melt is ejected through a meltblowing die to form a melt stream. The spinning temperature of the melt stream is set with reference to the melting point of the polymer base material.

[0088] In one embodiment, in step 2, the spinning temperature of the melt stream is 170-300° C. For example, the spinning temperature can be 170° C., 200° C., 220° C., 250° C., 270° C., 300° C., etc.

[0089] In a specific embodiment, in step 2, the flow rate of the metering pump is 15-40 r / min. Exemplarily, the flow rate of the metering pump can be 15 r / min, 20 r / min, 25 r / min, 30 r / min, 35 r / min, 40 r / min, etc., preferably 20-30 r / min.

[0090] In one specific embodiment, in step three, the melt stream meets the high-speed hot air flow at the outlet of the meltblowing die head, and the melt stream is stretched and refined by the high-speed hot air flow, and spun to obtain metamaterial fibers. The metamaterial fibers fall evenly on the roller of the receiving device. When they roll quickly on the roller for one circle, the metamaterial fibers falling on the roller form a single-layer fiber spunbond layer.

[0091] In one specific embodiment, in step three, the melt stream meets the high-speed hot air flow at the outlet of the meltblowing die head, and the melt stream is stretched and refined by the high-speed hot air flow, and spun to obtain metamaterial fibers. The metamaterial fibers fall evenly on the roller of the receiving device, and the number of turns N of the roller is controlled. By repeated meltblowing, a metamaterial spunbond fabric including N single-layer fiber spunbond layers is obtained.

[0092] In one embodiment, the temperature of the hot air flow is set with reference to the melting point of the polymer substrate material. Specifically, the temperature of the high-speed hot air flow is 160-485°C. Exemplarily, the temperature of the high-speed hot air flow can be 160°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 485°C, etc.

[0093] In a specific embodiment, the receiving distance is 30-70 cm. For example, the receiving distance, which is the distance between the meltblown head and the fiber receiving surface of the roller, can be 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, etc., among which 40-60 cm is preferred; the winding speed of the roller is 5-45 m / min, for example, the winding speed can be 5 m / min, 10 m / min, 15 m / min, 20 m / min, 25 m / min, 30 m / min, 35 m / min, 40 m / min, 45 m / min, etc., among which 15-35 m / min is preferred.

[0094] In one embodiment, after step three, the metamaterial spunbond fabric can be further reinforced by hot rolling bonding, and the hot rolling temperature is set with reference to the glass transition temperature of the polymer substrate material. Specifically, the hot rolling temperature of the hot rolling mill is 30-150°C, for example, 30°C, 60°C, 90°C, 120°C, 150°C, etc.; the winding speed of the hot rolling mill is 4-60m / min, for example, 4m / min, 10m / min, 15m / min, 20m / min, 25m / min, 30m / min, 35m / min, 40m / min, 45m / min, 50m / min, 55m / min, 60m / min, etc., preferably 10-40m / min; the thickness of the metamaterial spunbond fabric after hot rolling bonding is 0.1-1.5mm, for example, 0.1mm, 0.5mm, 1.0mm, 1.5mm, preferably 0.5-1.5mm, and more preferably 0.6mm.

[0095] By means of heat treatment, the fiber polymers in each single-layer fiber spunbond layer are softened and physically bonded. After cooling and solidification, a stable fiber grid structure is formed to maintain the overall mechanical strength of the metamaterial spunbond fabric with a high content of micro-nanoparticles.

[0096] According to a third aspect of the present application, there is also provided a metamaterial spunbond fabric prepared by the method for preparing the metamaterial spunbond fabric according to any of the aforementioned embodiments.

[0097] The metamaterial spunbond fabric of the present application includes at least one single-layer fiber spunbond layer, wherein the single-layer fiber spunbond layer includes metamaterial fibers and pores formed by interweaving and overlapping the metamaterial fibers. The metamaterial fibers include a polymer base material and micro-nanoparticles. By controlling the diameter of the reflective pores, the percentage of the total volume of the reflective pores to the volume of the spunbond fabric, the average particle size of the micro-nanoparticles, the doping concentration of the micro-nanoparticles, and the types of the micro-nanoparticles and the polymer base material, the mid-infrared (8-13 μm) emissivity reaches above 89%, or even 94%, and the solar radiation (0.3-2.5 μm) reflectivity reaches above 86%, or even 95%. Example

[0098] In order to better illustrate the technical solutions and advantages of this application, the following will further illustrate this application with reference to specific embodiments. The process parameters, raw materials, etc. not described in detail in this application are all carried out according to conventional technical means in this field.

[0099] In the following examples, the emissivity of spunbond fabrics in the mid-infrared (8-13 μm) band was measured using a Fourier transform infrared spectrometer combined with an integrating sphere; and the reflectivity of spunbond fabrics in the solar radiation (0.3-2.5 μm) band was measured using a UV-VIS-NIR spectrophotometer combined with an integrating sphere.

[0100] In the following examples, the names and sources of the raw materials are as follows:

[0101] Titanium dioxide (Xiaochao Nano, XH-TiO2-500)

[0102] Zinc oxide (Xuancheng Jingrui New Materials VK-J500)

[0103] Polyethylene terephthalate (Dayouguang chips from Jiaxing Yipeng Chemical Fiber Co., Ltd.)

[0104] Polypropylene (Shanghai Petrochemical Y2600T)

[0105] Polyvinylidene fluoride (Solef 6008)

[0106] Polylactic acid (Total LX175)

[0107] Example 1

[0108] 600g of PET particles were mixed with 400g of TiO2 particles with a particle size of 0.1μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 280℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0109] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 290°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 15r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 60cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.1-0.2μm and a reflective pore volume of 50% are obtained.

[0110] Example 2

[0111] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 0.2μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was sent to a slicer through a guide wheel for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0112] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 15r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 60cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.1-0.2μm and a reflective pore volume of 50% are obtained.

[0113] Example 3

[0114] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 1μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0115] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 40r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 60cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric with a reflective pore diameter of 1-3μm and a reflective pore volume of 50% is obtained by hot rolling and bonding reinforcement using a rolling mill.

[0116] Example 4

[0117] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 3μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0118] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 15r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 60cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric with a reflective pore diameter of 1-3μm and a reflective pore volume of 50% is obtained by hot rolling and bonding reinforcement using a rolling mill.

[0119] Example 5

[0120] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 0.5μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0121] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.4-0.7μm and a reflective pore volume of 50% are obtained.

[0122] Example 6

[0123] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 0.35μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was sent to a slicer through a guide wheel for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0124] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 45cm. The winding speed of the curtain drum is 25m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.3-0.9μm and a reflective pore volume of 50% are obtained.

[0125] Example 7

[0126] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 0.5μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0127] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain drum is 15m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.4-0.7μm and a reflective pore volume of 85% are obtained.

[0128] Example 8

[0129] 950g of PLA particles were mixed with 50g of TiO2 particles with a particle size of 0.5μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was sent to a slicer through a guide wheel for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0130] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.4-0.7μm and a reflective pore volume of 50% are obtained.

[0131] Example 9

[0132] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 0.5μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0133] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.4-0.7μm and a reflective pore volume of 50% are obtained.

[0134] Example 10

[0135] 600g of PP particles were mixed with 400g of TiO2 particles with a particle size of 0.5μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0136] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain drum is 30m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.4-0.7μm and a reflective pore volume of 50% are obtained.

[0137] Example 11

[0138] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 0.5μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0139] After the composite material is dried, it is put into a large screw for melt extrusion, and the heating temperature is set to 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain a metamaterial fiber doped with 40% inorganic micro-nano particles and formed into a web on a mesh curtain with a receiving distance of 40cm, and the winding speed of the curtain drum is 40m / min; then the raw material is replaced with PLA particles, and spun into a web on the same mesh curtain, and the winding speed of the curtain drum is 15m / min; hot rolling bonding and reinforcement are carried out using a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore diameter of 0.4-0.7μm, a bottom reflective pore volume of 15%, a bottom inorganic micro-nano particle doping amount of 40%, a top reflective pore volume of 85%, and a top inorganic micro-nano particle doping amount of 0%.

[0140] Example 12

[0141] 950g of PVDF particles were mixed with 50g of 0.5μm TiO2 particles and added to the feed port of a twin-screw extruder. The heating temperature was set to 210°C. The extruded molten ribbon was solidified in a room-temperature water bath and then passed through a guide wheel to a slicer for pelletizing, resulting in a full-spectrum reflective composite material with a 5% inorganic micro-nano particle doping level. The same process was followed by melt extrusion of 600g of PVDF particles and 400g of 0.5μm TiO2 particles to produce a full-spectrum reflective composite material with a 40% inorganic micro-nano particle doping level.

[0142] The composite material with an inorganic micro-nano particle doping amount of 40% was dried and put into a large screw for melt extrusion. The heating temperature was set to 220°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it was pulled by air flow to obtain a metamaterial fiber doped with 40% inorganic micro-nano particles and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain roller was 40m / min. The raw material was then replaced with a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 5%, and spun into a web on the same mesh curtain. The winding speed of the curtain roller was 15m / min. The fabric was hot-rolled and bonded using a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore diameter of 0.4-0.7μm, a bottom reflective pore volume of 15%, a bottom inorganic micro-nano particle doping amount of 40%, a top reflective pore volume of 85%, and a top inorganic micro-nano particle doping amount of 5%.

[0143] Example 13

[0144] Take the full-spectrum reflective composite material of Example 2 and the full-spectrum reflective composite material of Example 3.

[0145] The full-spectrum reflective composite material of Example 3 was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 15r / min for spinning. After cooling, the air flow was pulled to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 60cm. The winding speed of the curtain roller was 30m / min. The raw material was then replaced with the full-spectrum reflective composite material of Example 2. The composite material was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was The melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 40r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 30cm. The winding speed of the curtain roller is 30m / min. The hot rolling bonding reinforcement is carried out on a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore volume of 50%, an inorganic micro-nano particle doping amount of 40%, a bottom reflective pore diameter of 1-3μm, a doped particle diameter of 1μm, a top reflective pore diameter of 0.1-0.2μm, and a doped particle diameter of 0.2μm.

[0146] Example 14

[0147] Take the full-spectrum reflective composite material of Example 2 and the full-spectrum reflective composite material of Example 5.

[0148] The full-spectrum reflective composite material of Example 5 was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the air flow was pulled to obtain a metamaterial fiber and formed into a web on a mesh curtain with a receiving distance of 60cm. The winding speed of the curtain roller was 30m / min. The raw material was then replaced with the full-spectrum reflective composite material of Example 2. The composite material was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the metamaterial fiber was formed into a web on a mesh curtain with a receiving distance of 60cm. The winding speed of the curtain roller was 30m / min. The melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 40 r / min for spinning. After cooling, it was pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 30 cm. The winding speed of the curtain roller was 30 m / min. The fabric was hot-rolled and bonded on a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore volume of 50%, an inorganic micro-nano particle doping amount of 40%, a bottom reflective aperture of 0.4-0.7 μm, a doped particle particle size of 0.5 μm, a top reflective aperture of 0.1-0.2 μm, and a doped particle particle size of 0.2 μm.

[0149] Example 15

[0150] Take the full-spectrum reflective composite material of Example 2 and the full-spectrum reflective composite material of Example 6.

[0151] The full-spectrum reflective composite material of Example 6 was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the air flow was pulled to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 45cm. The winding speed of the curtain roller was 30m / min. The raw material was then replaced with the full-spectrum reflective composite material of Example 2. The composite material was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the metamaterial fiber was formed into a web on a mesh curtain with a receiving distance of 45cm. The winding speed of the curtain roller was 30m / min. The melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 15 r / min for spinning. After cooling, it was pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 60 cm. The winding speed of the curtain roller was 30 m / min. The fabric was hot-rolled and bonded on a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore volume of 50%, an inorganic micro-nano particle doping amount of 40%, a bottom reflective aperture of 0.3-0.9 μm, a doped particle particle size of 0.35 μm, a top reflective aperture of 0.1-0.2 μm, and a doped particle particle size of 0.2 μm.

[0152] Example 16

[0153] Take the full-spectrum reflective composite material of Example 3 and the full-spectrum reflective composite material of Example 5.

[0154] The full-spectrum reflective composite material of Example 5 was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the air flow was pulled to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain roller was 30m / min. The raw material was then replaced with the full-spectrum reflective composite material of Example 3. The composite material was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was The melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 40r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 30cm. The winding speed of the curtain roller is 30m / min. The hot rolling bonding reinforcement is carried out on a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore volume of 50%, an inorganic micro-nano particle doping amount of 40%, a bottom reflective pore diameter of 0.4-0.7μm, a doped particle diameter of 0.5μm, a top reflective pore diameter of 1-3μm, and a doped particle diameter of 1μm.

[0155] Example 17

[0156] Take the full-spectrum reflective composite material of Example 3 and the full-spectrum reflective composite material of Example 6.

[0157] The full-spectrum reflective composite material of Example 6 was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the air flow was pulled to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 45cm. The winding speed of the curtain roller was 30m / min. The raw material was then replaced with the full-spectrum reflective composite material of Example 3. The composite material was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was The melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 40r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 30cm. The winding speed of the curtain roller is 30m / min. The hot rolling bonding reinforcement is carried out on a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore volume of 50%, an inorganic micro-nano particle doping amount of 40%, a bottom reflective pore diameter of 0.3-0.9μm, a doped particle particle diameter of 0.35μm, a top reflective pore diameter of 1-3μm, and a doped particle particle diameter of 1μm.

[0158] Example 18

[0159] Take the full-spectrum reflective composite material of Example 5 and the full-spectrum reflective composite material of Example 6.

[0160] The full-spectrum reflective composite material of Example 6 was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the air flow was pulled to obtain a metamaterial fiber and formed into a web on a mesh curtain with a receiving distance of 45cm. The winding speed of the curtain roller was 30m / min. The raw material was then replaced with the full-spectrum reflective composite material of Example 5. The composite material was dried and put into a large screw for melt extrusion, and the heating temperature was set to 210°C. The extruded melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, the metamaterial fiber was formed into a web on a mesh curtain with a receiving distance of 45cm. The winding speed of the curtain roller was 30m / min. The melt was filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30 r / min for spinning. After cooling, it was pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40 cm. The winding speed of the curtain roller was 30 m / min. The fabric was hot-rolled and bonded on a rolling mill to obtain a metamaterial spunbond fabric with a reflective pore volume of 50%, an inorganic micro-nano particle doping amount of 40%, a bottom reflective pore diameter of 0.3-0.9 μm, a doped particle diameter of 0.35 μm, a top reflective pore diameter of 0.4-0.7 μm, and a doped particle diameter of 0.5 μm.

[0161] Example 19

[0162] 600g of PLA particles were mixed with 400g of TiO2 particles with a particle size of 0.5μm and added to the feed port of a twin-screw extruder. The heating temperature was set to 200℃. The extruded molten cast ribbon was solidified in a room temperature water bath. The cast ribbon was passed through a guide wheel to a slicer for pelletizing to obtain a full-spectrum reflective composite material with an inorganic micro-nano particle doping amount of 40%.

[0163] After drying, the composite material is put into a large screw for melt extrusion. The heating temperature is set at 210°C. The extruded melt is filtered through a melt filter and quantitatively transported by a metering pump at a speed of 30r / min for spinning. After cooling, it is pulled by air flow to obtain metamaterial fibers and formed into a web on a mesh curtain with a receiving distance of 40cm. The winding speed of the curtain drum is 45m / min. The metamaterial spunbond fabric is obtained by hot rolling and bonding reinforcement using a rolling mill, and a reflective pore diameter of 0.4-0.7μm and a reflective pore volume of 10% are obtained.

[0164] Table 1 Infrared emissivity and reflectivity measurement results

[0165]

[0166] Table 1 shows the infrared emissivity and reflectivity measurements of the metamaterial spunbond fabrics of various examples and comparative examples. Comparative Example 1 is a conventional spunbond fabric obtained from a mask sample. The polymer matrix is ​​polypropylene, undoped with micro-nanoparticles, and the proportion of reflective pores with a diameter of 100 nm to 3000 nm is less than 10%.

[0167] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A metamaterial spunbond fabric, characterized in that: The metamaterial spunbond fabric comprises two single-layer fiber spunbond layers, the two single-layer fiber spunbond layers are stacked, the single-layer fiber spunbond layers comprise metamaterial fibers, and the metamaterial fibers are interwoven and stacked to form pores; Among the pores, pores with a diameter of 400-700 nm are reflective pores; In the inner layer of the metamaterial spunbond fabric, the reflective pores account for 15% of the volume fraction of the single fiber spunbond layer; in the outer layer of the metamaterial spunbond fabric, the reflective pores account for 85% of the volume fraction of the single fiber spunbond layer; In the inner layer of the metamaterial spunbond fabric, the metamaterial fibers are formed of a composite material including a polymer base material and micro-nano particles, and the mass of the micro-nano particles is 40% of the mass of the polymer base material in the layer; In the outer layer of the metamaterial spunbond fabric, the metamaterial fibers are formed from a polymer base material; The average particle size of the micro-nano particles is 500 nm; The micro-nano particles are titanium dioxide TiO2; The polymer base material is polylactic acid PLA.

Images