Multifunctional passive cooling optical metamaterial fiber, yarn and fabric and preparation method thereof

Abstract

The invention provides a multifunctional passive cooling optical metamaterial fiber, yarn and fabric and a preparation method thereof. The passive cooling optical metamaterial fiber is composed of high-refractive-index inorganic micro-nano particles and / or a micro-nano functional material and a polymer substrate material. Wherein wavelength / sub-wavelength scale micro-nano particles are uniformly distributed in a substrate material as a random scattering medium to form a random optical metamaterial system, and reflection enhancement of the optical metamaterial fabric in a solar spectrum band is realized by utilizing a multiple Mie resonance collective effect. According to the passive cooling optical metamaterial fiber, a circular structure, a skin-core structure and the like are prepared through melt spinning, high-refractive-index inorganic micro-nano particles are added into a skin layer and used for sunlight band wide spectrum regulation and control, and a micro-nano functional material is added into a core layer, so that multiple functions are effectively achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of functional textiles, and particularly relates to a multifunctional passive cooling optical metamaterial fiber, yarn, fabric and a preparation method thereof. Background Art

[0002] With the frequent occurrence of extreme high-temperature weather caused by global warming, people are inevitably harmed by outdoor high temperatures and sunlight exposure, resulting in health problems such as skin burns, heat stroke, and even heat stroke. However, most textiles have limited cooling effects in direct sunlight outdoors, cannot block the huge input of solar radiation energy, and inevitably lead to an increase in skin temperature, making it difficult to meet the outdoor cooling requirements. At present, people's requirements for textiles are getting higher and higher. Among them, functional textiles have received extensive attention and love because they can improve human comfort.

[0003] A prior patent discloses a sweat-cooling fabric, in which a super-hydrophilic structure is formed on one side surface of a hydrophobic fabric, so that one side of the fabric is a hydrophobic surface and the other side is a hydrophilic surface. This invention enables the sweat on the hydrophobic surface of the fabric to quickly penetrate to the hydrophilic surface of the fabric and quickly evaporate on the hydrophilic surface of the fabric, having a good sweat-cooling function. The fabric design of the above method does not involve the regulation of the broad spectrum of the solar band and is difficult to block the input of external energy, so the cooling effect is limited.

[0004] A prior patent discloses a light-shielding and cooling fabric, which includes a base fabric and a first bonding layer and a cooling layer sequentially laminated on the surface of the base fabric. The surface of the cooling layer away from the first bonding layer is the light-incident side; the light-shielding and cooling fabric has excellent light-shielding performance and excellent radiative cooling function at the same time. The above method effectively regulates the transmittance of sunlight in the 0.3μm - 2.5μm band, but does not have other functions and has a single function.

[0005] A prior patent discloses a composite cooling and breathable silk fabric, which includes a skin-friendly layer, a cooling and heat-conducting layer, a waterproof and breathable layer, a protective layer, and an anti-ultraviolet layer. The cooling and heat-conducting layer is a mica ice-cooling fiber layer. The mica ice-cooling fiber layer has good heat conductivity, water absorption, and adsorption properties, and can improve the cool feeling and comfort during wearing. However, the above fabric lacks the regulation of the full-spectrum of sunlight and has a complex structure and a cumbersome preparation process, making it difficult to achieve large-scale production.

[0006] At present, the sun-protective clothing on the market has good ultraviolet protection function, but the actual cooling effect is poor, and it cannot achieve excellent thermal comfort performance while effectively preventing the harm of ultraviolet rays to the human body. In addition, most of the existing outdoor sun-protective clothing realizes the ultraviolet protection function through doping or post-treatment methods. However, doping leads to a decrease in fiber strength and faces the problem of inability to carry out large-scale preparation. The sun-protective clothing prepared by the post-treatment method has a significant decline in effect after long-term use and multiple washes. Existing functional fabrics can provide a cool feeling for human skin by increasing the thermal conductivity of the material. However, these fabrics do not have spectral regulation functions, and their cooling efficiency in high-temperature and high-humidity environments is very limited. Therefore, there is a lack of a multifunctional passive cooling fabric technology designed from the three-dimensional structures of fibers, yarns, and fabrics, enabling the fibers to have multifunctions such as heat conduction, moisture absorption, and antibacterial while possessing excellent cooling performance, so as to prepare passive cooling and heatstroke-preventing fabrics suitable for human skin protection, and achieve large-scale batch preparation, with the advantages of low cost and high production efficiency.

[0007] Based on the above-mentioned defects existing in the prior art, it is necessary to improve this. Summary of the Invention

[0008] In order to solve the above problems, the present invention provides a multifunctional passive cooling optical metamaterial fiber, yarn, fabric and their preparation methods. Through the selection of high-refractive-index inorganic micro-nano particles and / or micro-nano functional materials, polymer base materials, and the design of fiber structures, the present invention realizes the effective regulation of the broadband spectrum of sunlight, that is, achieves a high reflection effect in the solar radiation band (0.3 - 2.5 μm), blocks the input of solar energy, especially a high reflection effect in the ultraviolet band (0.3 - 0.4 μm), and effectively prevents the harm of ultraviolet rays to the human body. In addition, the core-shell structure fibers, coated structure yarns and the double-sided fabrics made thereof in the present invention also have the effect of enhanced functions. In short, through the optimized design of the structural parameters at multiple scales and levels such as fibers, yarns, and fabrics, the present invention can achieve the efficient collaborative regulation of optical-thermal physical quantities under direct outdoor sunlight, providing the wearer with the best effect integrating functions such as heatstroke prevention, cooling, sun protection, cool feeling, moisture absorption, and antibacterial.

[0009] The specific technical solutions of the present invention are as follows:

[0010] In the first aspect, the present invention provides a preparation method of a multifunctional passive cooling optical metamaterial fiber, comprising the following steps:

[0011] Melting and extruding high-refractive-index inorganic micro-nano particles and / or micro-nano functional materials, polymer base materials to obtain a composite multi-material masterbatch;

[0012] Heating and melting the composite multi-material masterbatch, spraying it out through a spinneret hole to form a melt stream, and winding it to obtain a primary optical metamaterial filament;

[0013] The as - spun optical metamaterial filaments are heated and drawn to obtain passive cooling optical metamaterial fibers;

[0014] The refractive index n of the high - refractive - index inorganic micro - nano particles is n≥2.5;

[0015] The particle size of the high - refractive - index inorganic micro - nano particles is 50 - 800 nm;

[0016] The particle size of the micro - nano functional material is 50 - 800 nm.

[0017] Preferably, in the preparation method of the multifunctional passive cooling optical metamaterial fiber, the high - refractive - index inorganic micro - nano particles include at least one of titanium dioxide, zinc sulfide, silicon carbide, silicon nitride, zinc oxide, boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, calcium sulfate;

[0018] And / or, the micro - nano functional material includes at least one of hexagonal boron nitride, hexagonal silicon carbide, silver nanoparticles, copper nanoparticles, gold nanoparticles, ZnO, La2O3 nanoparticles, CeO2 nanoparticles, V2O5 nanoparticles, CuO nanoparticles, mica flakes, graphene flakes, flaky carbon powder, flake graphite, exfoliated graphite, expanded graphite, single - walled carbon nanotubes, multi - walled carbon nanotubes, fullerenes, carbon nanofibers, fibrous carbon powder, tungsten oxide, jade powder, medical stone powder, molybdenum disulfide, copper sulfide, copper nanowires, silver nanowires, boron nitride nanotubes, silicon carbide nanotubes, silicon carbide whiskers, iron oxide, TiO2, metal carbides and / or nitrides, metal - organic framework compounds, peroxidase derivatives;

[0019] And / or, the polymer base material includes at least one of polylactic acid, polyethylene terephthalate, polyvinylidene fluoride, polymethyl methacrylate, polypropylene, polyvinyl chloride, polystyrene, polyester and sodium m - isophthalate sulfonate copolymer, acrylate copolymer, polyethylene glycol, polytrimethylene terephthalate, polyvinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol, polyurethane, polyacrylonitrile, cycloolefin copolymer, polycarbonate, acrylonitrile - butadiene - styrene, polyoxymethylene, polyphenylene ether, polyimide, vinyl acetate resin, polyvinyl formal, polyvinyl acetate and polyvinyl acetal.

[0020] Preferably, in the preparation method of the multifunctional passive cooling optical metamaterial fiber, the structure of the passive cooling optical metamaterial fiber includes any one of a core - sheath structure, a cylindrical structure, a hollow cylindrical structure, and a sea - island structure.

[0021] Preferably, for the preparation method of the multifunctional passive cooling optical metamaterial fiber, the structure of the passive cooling optical metamaterial fiber is a core-shell structure, and the preparation method of the passive cooling optical metamaterial fiber comprises the following steps:

[0022] Melting and extruding high refractive index inorganic micro-nano particles or micro-nano functional materials and polymer substrate materials to obtain a cortical composite multi-material masterbatch;

[0023] Melting and extruding high refractive index inorganic micro-nano particles or micro-nano functional materials and polymer substrate materials to obtain a core composite multi-material masterbatch;

[0024] Respectively input the cortical composite multi-material masterbatch and the core composite multi-material masterbatch into two feeding ports of a melt compound spinning machine, and extrude through the spinneret holes with a core-shell structure to form a melt stream, and obtain a primary optical metamaterial filament with a core-shell structure after winding;

[0025] Heat-drawing the primary optical metamaterial filament with a core-shell structure to obtain a passive cooling optical metamaterial fiber with a core-shell structure;

[0026] The mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the cortical composite multi-material masterbatch is 1-40%;

[0027] The mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the core composite multi-material masterbatch is 1-40%.

[0028] Preferably, for the preparation method of the multifunctional passive cooling optical metamaterial fiber, the structure of the passive cooling optical metamaterial fiber is a cylinder structure, and the preparation method of the passive cooling optical metamaterial fiber comprises the following steps:

[0029] Melting and extruding high refractive index inorganic micro-nano particles or micro-nano functional materials and polymer substrate materials to obtain a composite multi-material masterbatch;

[0030] Heating and melting the composite multi-material masterbatch, and extruding through a circular spinneret hole to form a melt stream, and obtaining a primary optical metamaterial filament after winding;

[0031] Heat-drawing the primary optical metamaterial filament to obtain a passive cooling optical metamaterial fiber with a cylinder structure;

[0032] The mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the composite multi-material masterbatch is 1-40%.

[0033] Preferably, for the preparation method of the multifunctional passive cooling optical metamaterial fiber, the winding speed is 200 m / min to 1200 m / min;

[0034] The heating and drawing of the as-spun optical metamaterial filaments specifically includes the following steps:

[0035] The as-spun optical metamaterial filaments are successively passed through a first heating roller and a second heating roller along the filament direction and stretched. Among them, the temperature of the first heating roller is 70-90 °C, the temperature of the second heating roller is 120-140 °C, the speed of the as-spun optical metamaterial filaments passing through the first heating roller is 90-110 m / min, and the speed of the as-spun optical metamaterial filaments passing through the second heating roller is 290-310 m / min.

[0036] The draw ratio is 1-4 times.

[0037] Preferably, in the preparation method of the multifunctional passive cooling optical metamaterial fiber, the diameter of the passive cooling optical metamaterial fiber is 10-100 μm.

[0038] In a second aspect, the present invention also provides an optical metamaterial yarn, which is obtained by spinning the passive cooling optical metamaterial fiber prepared by the above preparation method.

[0039] Preferably, for the optical metamaterial yarn, the structure of the optical metamaterial yarn is any one of a single yarn structure, a double ply structure, a multi-ply structure, a complex twist ply yarn structure, and a core-spun yarn structure.

[0040] In a third aspect, the present invention also provides a multifunctional optical metamaterial fabric, which is obtained by weaving the above optical metamaterial yarn.

[0041] The preparation method of the passive cooling optical metamaterial fiber of the present invention has the following beneficial effects compared with the prior art:

[0042] 1. The preparation method of the passive cooling optical metamaterial fiber of the present invention. The passive cooling optical metamaterial fiber is composed of high refractive index inorganic micro-nano particles and / or micro-nano functional materials, and a polymer substrate material. Among them, micro-nano particles with a wavelength / sub-wavelength scale are used as random scattering media and uniformly distributed inside the substrate material to form a random optical metamaterial system. By utilizing the collective effect of multiple Mie resonances, the reflection enhancement of the optical metamaterial fabric in the solar spectrum band is realized. The passive cooling optical metamaterial fiber of the present invention is prepared by melt spinning to obtain a circular structure, a core-shell structure, etc. Among them, high refractive index inorganic micro-nano particles are added to the cortex for broadband spectral regulation in the sunlight band, and micro-nano functional materials are added to the core layer to effectively achieve multiple functions. The passive cooling optical metamaterial yarn of the present invention can be a core-spun yarn structure, where the outer layer is a broadband spectral regulation yarn and the inner layer is a multi-functional yarn. The passive cooling optical metamaterial fabric of the present invention can be a single-sided structure or a double-sided structure. Its outer layer has excellent broadband spectral regulation performance, and the inner layer has multi-functional performance. The present invention obtains a passive cooling optical metamaterial fabric with both extremely strong solar spectrum reflection regulation ability and multi-functional performance through a hierarchical structure design in three dimensions of fiber, yarn, and fabric;

[0043] 2. The passive cooling optical metamaterial fiber, yarn, and fabric of the present invention are based on hierarchical material structure design and optical structure design, thereby generating a broadband optical response in the selective sunlight band of 0.3 - 2.5 μm and excellent multi-functional performance. Thus, while realizing the guidance and manipulation of solar radiation, the thermal parameters such as heat conduction and convective evaporation are also effectively regulated, and the light-thermal co-regulation is carried out for the micro-environment temperature between the textile and the human skin to achieve efficient thermal management. In addition, the fabric has excellent mechanical strength, wear resistance, breathability, antibacterial property, skin-friendly property, and comfort. The raw materials of the passive cooling optical metamaterial fiber, yarn, and fabric are widely sourced and have low production costs, and are expected to achieve large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 It is a schematic structural diagram of the passive cooling optical metamaterial fiber in Embodiment 1 of the present invention;

[0046] Figure 2 It is a schematic structural diagram of the passive cooling optical metamaterial yarn in Embodiment 4 of the present invention;

[0047] Figure 3SEM image of the passive cooling optical metamaterial fiber in Embodiment 7 of the present invention;

[0048] Figure 4 Distribution map of titanium element of the passive cooling optical metamaterial fiber in Embodiment 7 of the present invention;

[0049] Figure 5 Schematic diagram of the double-sided structure of the optical metamaterial fabric in Embodiment 7 of the present invention. Detailed implementation manners

[0050] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0051] For a better understanding of the present invention rather than limiting the scope of the present invention, all numbers representing amounts, percentages, and other numerical values used in this application should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise specified, the numerical parameters listed in the specification and the appended claims are approximate values, which may vary according to the different desired properties to be obtained. Each numerical parameter should be regarded as being obtained at least according to the reported significant figures and by the conventional rounding method.

[0052] It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments. In addition, in the description of this application, the term "comprising" means "including but not limited to". The various embodiments of the present invention may exist in a range format; it should be understood that the description in a range format is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual numerical values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0053] The present invention provides a preparation method for a passive cooling optical metamaterial fiber, comprising the following steps:

[0054] S1. Melt-extrude high refractive index inorganic micro-nano particles and / or micro-nano functional materials and a polymer substrate material to obtain a composite multi-material masterbatch;

[0055] S2. Heat and melt the composite multi-material masterbatch, eject it through a spinneret to form a melt stream, and wind it to obtain as-spun optical metamaterial filaments;

[0056] S3. Heat-draw the as-spun optical metamaterial filaments to obtain passive cooling optical metamaterial fibers;

[0057] The refractive index n of the high refractive index (n>2.5) inorganic micro-nano particles is n≥2.5;

[0058] The particle size of the high refractive index inorganic micro-nano particles is 50 - 800 nm;

[0059] The particle size of the micro-nano functional materials is 50 - 800 nm.

[0060] Specifically, in some embodiments, melt-extrude high refractive index inorganic micro-nano particles and / or micro-nano functional materials and a polymer substrate material to obtain a preliminary multi-material masterbatch; obtain a composite multi-material masterbatch through secondary melt-extrusion; heat and melt the composite multi-material masterbatch, eject it through a spinneret to form a melt stream, and wind it to obtain as-spun optical metamaterial filaments; heat-draw the as-spun optical metamaterial filaments, wind them, and then continue to heat, curl, and cut to obtain optical metamaterial fibers. In some embodiments, the high refractive index inorganic micro-nano particles are selected from at least one of 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).

[0061] In some embodiments, the micro-nano functional materials include at least one of hexagonal boron nitride, hexagonal silicon carbide, silver nanoparticles, copper nanoparticles, gold nanoparticles, La2O3 nanoparticles, CeO2 nanoparticles, V2O5 nanoparticles, CuO nanoparticles, mica flakes, graphene flakes, flaky carbon powder, flake graphite, exfoliated graphite, expanded graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, fullerenes, nanofibers, fibrous carbon powder, tungsten oxide, jade powder, medical stone powder, molybdenum disulfide (MoS2), copper sulfide (CuS), copper nanowires, silver nanowires, boron nitride nanotubes, silicon carbide nanotubes, silicon carbide whiskers, iron oxide, ZnO, TiO2, graphene-based, metal carbides and nitrides, metal-organic framework compounds (MOFs), and peroxidase derivatives.

[0062] In some embodiments, the polymer substrate material is selected from at least one of polylactic acid (PLA), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polypropylene (PP), 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), polyurethane (PU), polyacrylonitrile (PAN), cycloolefin copolymer (COC), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polyoxymethylene (POM), polyphenylene ether (PPO), polyimide (PI), vinyl acetate resin, polyvinyl formal, polyvinyl acetate (PVAC), and polyvinyl acetal.

[0063] In some embodiments, the structure of the passive cooling optical metamaterial fiber includes any one of a core-shell structure, a cylindrical structure, a hollow cylindrical structure, and a sea-island structure.

[0064] In some embodiments, the structure of the passive cooling optical metamaterial fiber is a core-shell structure, and the preparation method of the passive cooling optical metamaterial fiber includes the following steps:

[0065] S1. Melting and extruding high refractive index inorganic micro-nano particles or micro-nano functional materials and polymer substrate materials to obtain a cortical composite multi-material masterbatch;

[0066] S2. Melting and extruding high refractive index inorganic micro-nano particles or micro-nano functional materials and polymer substrate materials to obtain a core layer composite multi-material masterbatch;

[0067] S3. Respectively feeding the cortical composite multi-material masterbatch and the core layer composite multi-material masterbatch into two feeding ports of a melt compound spinning machine, and ejecting through the spinneret holes of the core-shell structure to form melt filaments, and obtaining the primary optical metamaterial filaments with a core-shell structure after winding;

[0068] S4. Heating and drawing the primary optical metamaterial filaments with a core-shell structure to obtain the passive cooling optical metamaterial fibers with a core-shell structure;

[0069] Among them, the mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the cortical composite multi-material masterbatch is 1-40%;

[0070] The mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the core layer composite multi-material masterbatch is 1-40%.

[0071] Specifically, in some embodiments, a method for preparing a core-shell structured passive cooling optical metamaterial fiber includes the following steps:

[0072] S1. Melting and extruding high refractive index inorganic micro-nano particles and a polymer substrate material to obtain a skin-layer composite multi-material masterbatch;

[0073] S2. Melting and extruding micro-nano functional materials and a polymer substrate material to obtain a core-layer composite multi-material masterbatch;

[0074] S3. Respectively feeding the skin-layer composite multi-material masterbatch and the core-layer composite multi-material masterbatch into two feeding ports of a melt compound spinning machine, and ejecting through the spinneret holes with a core-shell structure to form a melt filament, and obtaining a nascent optical metamaterial filament with a core-shell structure after winding;

[0075] S4. Heating and drawing the nascent optical metamaterial filament with a core-shell structure to obtain a passive cooling optical metamaterial fiber with a core-shell structure; specifically, heating and drawing the nascent optical metamaterial filament with a core-shell structure along the filament direction, setting the temperatures of two heating rollers to be 70 - 90 °C and 120 - 140 °C respectively, setting the feeding and winding speeds to be 90 - 110 m / min and 290 - 310 m / min respectively, and stretching the nascent filament by 2 - 4 times to obtain a passive cooling optical metamaterial fiber with a core-shell structure; specifically, heating and drawing the nascent optical metamaterial filament along the filament direction and passing through two heating rollers in sequence (the rotation of the heating rollers drives the movement of the filament), specifically passing through the first heating roller and the second heating roller in sequence, the temperature of the first heating roller is 70 - 90 °C, the temperature of the second heating roller is 120 - 140 °C, the speed of the nascent optical metamaterial filament passing through the first heating roller is 90 - 110 m / min, and the speed of the nascent optical metamaterial filament passing through the second heating roller is 290 - 310 m / min.

[0076] Among them, the mass fraction of the high refractive index inorganic micro-nano particles in the skin-layer composite multi-material masterbatch is 1 - 40%, specifically, the mass fraction can be 1%, 2%, 3%, 5%, 7%, 9%, 10%, 12%, 15%, 17%, 19%, 21%, 24%, 27%, 30%, 32%, 34%, 36%, 38%, 40%; the mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the core-layer composite multi-material masterbatch is 1 - 40%, specifically, the mass fraction can be 1%, 2%, 3%, 5%, 7%, 9%, 10%, 12%, 15%, 17%, 19%, 21%, 24%, 27%, 30%, 32%, 34%, 36%, 38%, 40%.

[0077] In some embodiments, the structure of the passive cooling optical metamaterial fiber is a cylinder structure, and a method for preparing the passive cooling optical metamaterial fiber includes the following steps:

[0078] S1. Melt and extrude high refractive index inorganic micro-nano particles or micro-nano functional materials and polymer substrate materials to obtain a composite multi-material masterbatch;

[0079] S2. Heat and melt the composite multi-material masterbatch, eject it through a circular spinneret hole to form a melt stream, and obtain as-spun optical metamaterial filaments after winding;

[0080] S3. Heat and draw the as-spun optical metamaterial filaments to obtain a passive cooling optical metamaterial fiber with a cylindrical structure; specifically, heat and draw the as-spun optical metamaterial filaments along the filament direction, set the temperatures of two heating rollers to be 70 - 90 °C and 120 - 140 °C respectively, set the feeding and winding speeds to be 90 - 110 m / min and 290 - 310 m / min respectively, and make the as-spun filaments heat-drawn by 2 - 4 times, thereby obtaining a passive cooling optical metamaterial fiber with a cylindrical structure;

[0081] S4. The mass fraction of high refractive index inorganic micro-nano particles or micro-nano functional materials in the composite multi-material masterbatch is 1 - 40%, specifically, the mass fraction can be 1%, 2%, 3%, 5%, 7%, 9%, 10%, 12%, 15%, 17%, 19%, 21%, 24%, 27%, 30%, 32%, 34%, 36%, 38%, 40%.

[0082] In some embodiments, the diameter of the passive cooling optical metamaterial fiber is 10 - 100 μm, preferably 20 - 40 μm.

[0083] Based on the same inventive concept, the present invention also provides an optical metamaterial yarn, which is obtained by spinning the passive cooling optical metamaterial fiber prepared by the above preparation method.

[0084] Specifically, the structure of the optical metamaterial yarn is any one of a single yarn structure, a double ply structure, a multi-ply structure, a complex twist ply yarn structure, and a core-spun yarn structure.

[0085] In some embodiments, for the core-spun yarn structure optical metamaterial yarn of the present invention, its outer layer can be composed of solar spectrum highly reflective fibers (i.e., obtained by heating and melting, and heating and drawing a composite multi-material masterbatch containing high refractive index inorganic micro-nano particles and polymer substrate materials), and its inner layer can be composed of solar spectrum highly reflective fibers, multifunctional fibers (i.e., obtained by heating and melting, and heating and drawing a composite multi-material masterbatch containing micro-nano functional materials and polymer substrate materials), or a mixture of highly reflective fibers and multifunctional fibers.

[0086] Based on the same inventive concept, the present invention also provides an optical metamaterial fabric, which is obtained by weaving the above optical metamaterial yarn.

[0087] Specifically, the optical metamaterial fabric structure can be a basic weave (plain weave, twill weave, satin weave, etc.), a modified weave (double plain weave, basket weave, enhanced twill weave, compound twill weave, mountain twill weave, diamond twill weave, herringbone twill weave, zigzag twill weave, enhanced satin weave, irregular satin weave), or a fancy weave (striped and checked weave, openwork weave, rib weave, honeycomb weave, double-layer weave, terry weave, etc.).

[0088] In some embodiments, the optical metamaterial fabric of the present invention has a double-sided structure, with an outer layer being a full solar spectrum high-reflection layer prepared from optical metamaterial yarns (single yarns), and an inner layer being a multifunctional layer woven from multifunctional yarns or a fabric layer woven from ordinary yarns.

[0089] The passive cooling optical metamaterial fiber of the present invention is composed of high refractive index inorganic micro-nano particles and / or micro-nano functional materials and a polymer base material; among them, micro-nano particles with a wavelength / sub-wavelength scale are uniformly distributed inside the base material as a random scattering medium to form a random optical metamaterial system, and the collective effect of multiple Mie resonances is utilized to achieve enhanced reflection of the optical metamaterial fabric in the solar spectrum band. The passive cooling optical metamaterial fiber of the present invention is prepared by melt spinning to obtain a circular structure, a core-shell structure, etc., where high refractive index inorganic micro-nano particles are added to the cortex for broadband spectral regulation in the sunlight band, and micro-nano functional materials are added to the core layer to effectively achieve multiple functions. The passive cooling optical metamaterial yarn of the present invention can be a core-spun yarn structure, where the outer layer is a broadband spectral regulation yarn and the inner layer is a multifunctional yarn. The passive cooling optical metamaterial fabric of the present invention can be a single-sided structure or a double-sided structure, with its outer layer having excellent broadband spectral regulation performance and its inner layer having multifunctional performance. The present invention obtains a passive cooling optical metamaterial fabric with both extremely strong solar spectrum reflection regulation ability and multifunctional performance through hierarchical structure design in three dimensions: fiber, yarn, and fabric.

[0090] The passive cooling optical metamaterial fiber, yarn, and fabric of the present invention generate a broadband optical response in the selective sunlight band of 0.3 - 2.5 μm and excellent multifunctional performance based on hierarchical material structure design and optical structure design, thereby effectively regulating thermal parameters such as heat conduction and convective evaporation while guiding and manipulating solar radiation, and achieving efficient thermal management through photo-thermal co-regulation of the microenvironment temperature between the textile and the human skin. In addition, the fabric has excellent mechanical strength, abrasion resistance, breathability, antibacterial property, skin-friendly property, and comfort. The raw materials of the passive cooling optical metamaterial fiber, yarn, and fabric are widely sourced and have low production costs, and are expected to achieve large-scale production.

[0091] The following further illustrates the passive cooling optical metamaterial fiber, yarn, fabric and their preparation methods of the present invention with specific embodiments. This part further describes the content of the present invention in combination with specific embodiments, but should not be construed as a limitation of the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0092] In the following embodiments, a Fourier transform infrared spectrometer combined with an integrating sphere is used to measure the emissivity of the metamaterial fabric in the mid-infrared (8 - 13 μm) band; a UV-VIS-NIR spectrophotometer combined with an integrating sphere is used to measure the reflectivity of the metamaterial fabric in the solar radiation (0.3 - 2.5 μm) band.

[0093] In the following embodiments, the names and sources of each raw material are as follows:

[0094] Titanium dioxide (purchased from Shanghai Xiaochao Nano Technology Co., Ltd.)

[0095] Polylactic acid (Total LX175)

[0096] Silver nanoparticles (purchased from Zhongke Leiming (Beijing) Technology Co., Ltd.)

[0097] Flaky hexagonal boron nitride (purchased from Xi'an Ruixi Biotechnology Co., Ltd.)

[0098] Jade powder (purchased from LingShou County Chengnuo Mineral Products Co., Ltd.)

[0099] Example 1

[0100] The embodiment of the present application provides a preparation method of a passive cooling optical metamaterial fiber, including the following steps:

[0101] S1. Weigh 300 g of titanium dioxide particles (particle size is 0.4 μm, refractive index n = 2.6), and dry them at 150 °C for 24 hours to remove moisture; weigh 1200 g of polylactic acid and vacuum dry it at 130 °C for 24 h;

[0102] S2. Put the dried titanium dioxide particles and polylactic acid into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, vacuum dry it at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a cortical composite multi-material masterbatch, where the mass content of titanium dioxide is 20.00%;

[0103] S3. Weigh 100 g of silver nanoparticles (with a particle size of 0.5 μm) and dry them at 100 °C for 24 hours to remove moisture; weigh 1000 g of polylactic acid and dry it under vacuum at 130 °C for 24 h;

[0104] S4. Put the dried silver nanoparticles and polylactic acid into a twin-screw extruder, and carry out melt extrusion at 200 °C, then cool with water and send it to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; place the preliminary multi-material masterbatch in a room-temperature and ventilated environment for 5 h, and then carry out vacuum drying at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling and pelletizing at 205 °C to finally obtain a core-layer composite multi-material masterbatch, where the mass content of silver nanoparticles is 9.09%;

[0105] S5. Place the skin-layer composite multi-material masterbatch and the core-layer composite multi-material masterbatch in a room-temperature and ventilated environment for 5 h, and then carry out vacuum drying at 130 °C for more than 24 h;

[0106] Put the dried skin-layer composite multi-material masterbatch and core-layer composite multi-material masterbatch into two feeding ports of a melt compound spinning machine respectively, heat and melt them at 205 °C. The skin-layer composite multi-material masterbatch and the core-layer composite multi-material masterbatch are ejected through the spinneret holes with a core-shell structure to form melt filaments, and the primary drawn filaments are obtained at a winding speed of 600 m / min;

[0107] S6. Carry out heating and drawing of the primary drawn filaments along the filament direction, set the temperatures of two heating rollers to 80 °C and 130 °C respectively, and set the feeding and winding speeds to 100 m / min and 300 m / min respectively (specifically, the primary optical metamaterial filaments pass through the first heating roller and the second heating roller in sequence. The temperature of the first heating roller is 80 °C, the temperature of the second heating roller is 130 °C, the speed of the primary optical metamaterial filaments passing through the first heating roller is 100 m / min, and the speed of the primary optical metamaterial filaments passing through the second heating roller is 300 m / min.), so that the primary drawn filaments are heated and drawn by 3 times, thereby obtaining a core-shell structured passive cooling optical metamaterial fiber, as Figure 1 shown.

[0108] Figure 1 In Figure 1, 1 is the core layer, 2 is the skin layer, 11 are the silver nanoparticles in the core layer, 22 is the polylactic acid, and 21 are the titanium dioxide particles in the skin layer.

[0109] After cutting the above-prepared passive cooling optical metamaterial fibers, open, card, draw, rove and spin them to obtain a core-shell structured passive cooling optical metamaterial yarn.

[0110] Finally, the above optical metamaterial yarns are subjected to steam treatment, sizing, warping, drawing-in, weaving, and desizing to obtain a passive cooling optical metamaterial fabric with a single-sided multi-material multi-functional hierarchical structure design. By adjusting its weaving warp and weft densities, the warp density is 140 threads / 5 cm, and the weft density is 92 threads / 5 cm.

[0111] The breaking strength of the fabric obtained in Example 1 is 167 N / 5 cm (reference standard: ISO 13934-1 "Textiles - Tensile properties of fabrics"), the tearing strength is 12.6 N (reference standard: ISO 13937-1-2000 "Textiles - Tear properties of fabrics - Part 1: Determination of tear force by the ballistic pendulum method"), the abrasion resistance is 4510 cycles (reference standard: ISO12947-1998 "Textiles - Determination of fabric abrasion resistance using the Martindale method"), the air permeability is 139 mm / s (reference standard: ISO 9237-1995 "Determination of air permeability of fabrics"), the antibacterial rate against Staphylococcus aureus is 92.4%, the antibacterial rate against Escherichia coli is 89.3%, and the antibacterial rate against Candida albicans is 84.7% (reference standard: FZ / T 73023-2006 "Antibacterial knitted fabrics").

[0112] Example 2

[0113] The embodiment of the present application provides a method for preparing a passive cooling optical metamaterial fiber, comprising the following steps:

[0114] S1. Weigh 100 g of titanium dioxide particles (particle size 0.4 μm, refractive index n = 2.6), and dry them at 150 °C for 24 hours to remove moisture; weigh 1200 g of polylactic acid and vacuum dry it at 130 °C for 24 h;

[0115] S2. Put the dried titanium dioxide particles and polylactic acid into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; place the preliminary multi-material masterbatch in a room-temperature ventilated environment for 5 h, and then vacuum dry it at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a skin-layer composite multi-material masterbatch, wherein the mass content of titanium dioxide is 7.69%;

[0116] S3. Weigh 80 g of silver nanoparticles (particle size 0.5 μm), and dry them at 100 °C for 24 hours to remove moisture; weigh 1000 g of polylactic acid and vacuum dry it at 130 °C for 24 h;

[0117] S4. Put the dried silver nanoparticles and polylactic acid into a twin-screw extruder, conduct melt extrusion at 200 °C, cool with water, and send it to a cutting machine for pelletizing to obtain a preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, conduct vacuum drying at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, conduct secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a core-layer composite multi-material masterbatch, where the mass content of silver nanoparticles is 7.41%.

[0118] S5. After placing the skin-layer composite multi-material masterbatch and the core-layer composite multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, conduct vacuum drying at 130 °C for more than 24 h.

[0119] Put the dried skin-layer composite multi-material masterbatch and core-layer composite multi-material masterbatch into two feeding ports of a melt compound spinning machine respectively. Under heating and melting at 205 °C, the skin-layer composite multi-material masterbatch and the core-layer composite multi-material masterbatch are ejected through the spinneret holes with a skin-core structure to form melt filaments, and primary drawn filaments are obtained at a winding speed of 600 m / min.

[0120] S6. Heat and draw the primary drawn filaments along the filament direction. Set the temperatures of two heating rollers to 80 °C and 130 °C respectively, and set the feeding and winding speeds to 100 m / min and 300 m / min respectively to heat and draw the primary drawn filaments by 3 times, thereby obtaining a passive cooling optical metamaterial fiber with a skin-core structure.

[0121] After cutting the above-prepared passive cooling optical metamaterial fiber, a circular passive cooling optical metamaterial yarn is prepared through the processes of opening, carding, drawing, roving, and spinning.

[0122] Finally, the above optical metamaterial yarn is subjected to steaming, sizing, warping, drawing-in, weaving, and desizing to obtain a passive cooling optical metamaterial fabric with a single-sided multi-material multi-functional hierarchical structure design. By adjusting its weaving warp and weft densities, the warp density is 141 per 5 cm, and the weft density is 90 per 5 cm.

[0123] The breaking strength of the fabric obtained in Example 2 was 174 N / 5 cm (reference standard: ISO 13934-1 "Textiles - Tensile properties of fabrics"), the tearing strength was 14.2 N (reference standard: ISO 13937-1-2000 "Textiles - Tear properties of fabrics - Part 1: Determination of tear force by the pendulum method"), the abrasion resistance was 4640 cycles (reference standard: ISO12947-1998 "Textiles - Determination of the resistance to abrasion of fabrics by the Martindale method"), the air permeability was 138 mm / s (reference standard: ISO 9237-1995 "Determination of air permeability of fabrics"), the antibacterial rate against Staphylococcus aureus was 88.2%, the antibacterial rate against Escherichia coli was 77.3%, and the antibacterial rate against Candida albicans was 74.6% (reference standard: FZ / T 73023-2006 "Antibacterial knitted fabrics").

[0124] Example 3

[0125] S1. Weigh 250 g of titanium dioxide particles (particle size of 0.4 μm, refractive index n = 2.6), and dry them at 150 °C for 24 hours to remove moisture; weigh 1200 g of polylactic acid and vacuum dry it at 130 °C for 24 h;

[0126] S2. Put the dried titanium dioxide particles and polylactic acid into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, vacuum dry it at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a skin-layer composite multi-material masterbatch, where the mass content of titanium dioxide is 17.24%;

[0127] S3. Weigh 50 g of silver nanoparticles (particle size of 0.5 μm), and dry them at 100 °C for 24 hours to remove moisture; weigh 1000 g of polylactic acid and vacuum dry it at 130 °C for 24 h;

[0128] S4. Put the dried silver nanoparticles and polylactic acid into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, vacuum dry it at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a core-layer composite multi-material masterbatch, where the mass content of silver nanoparticles is 4.76%;

[0129] S5. After placing the skin-layer composite multi-material masterbatch and the core-layer composite multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, vacuum dry them at 130 °C for more than 24 h;

[0130] Put the dried skin composite multi-material masterbatch and core composite multi-material masterbatch into two feeding ports of a melt compound spinning machine respectively. Under heating and melting at 205°C, the skin composite multi-material masterbatch and core composite multi-material masterbatch are ejected through the spinneret holes with a skin-core structure to form melt filaments, and the primary filaments are obtained at a winding speed of 600 m / min.

[0131] S6. Stretch the primary filaments along the filament direction by heating. Set the temperatures of two heating rollers to 80°C and 130°C respectively, and set the filament feeding and winding speeds to 100 m / min and 300 m / min respectively, so that the primary filaments are heated and stretched by 3 times, thereby obtaining the passive cooling optical metamaterial fiber with a skin-core structure.

[0132] After cutting the above-prepared passive cooling optical metamaterial fiber, a circular passive cooling optical metamaterial yarn is prepared through the processes of opening, carding, drawing, roving and spinning.

[0133] Finally, the above optical metamaterial yarn is subjected to steaming, sizing, warping, drawing-in, weaving, and desizing to obtain a passive cooling optical metamaterial fabric with a single-sided multi-material multi-functional hierarchical structure design. By adjusting its weaving warp and weft densities, the warp density is 141 per 5 cm, and the weft density is 90 per 5 cm.

[0134] The breaking strength of the fabric obtained in Example 3 is 158 N / 5 cm (reference standard: ISO 13934-1 "Textiles - Tensile properties of fabrics"), the tearing strength is 12.2 N (reference standard: ISO 13937-1-2000 "Textiles - Tear properties of fabrics - Part 1: Determination of tear strength by the ballistic pendulum method"), the abrasion resistance is 4450 times (reference standard: ISO12947-1998 "Textiles - Determination of fabric resistance to abrasion using the Martindale method"), the air permeability is 130 mm / s (reference standard: ISO 9237-1995 "Determination of air permeability of fabrics"), the antibacterial rate against Staphylococcus aureus is 70.5%, the antibacterial rate against Escherichia coli is 69.5%, and the antibacterial rate against Candida albicans is 64.7% (reference standard: FZ / T 73023-2006 "Antibacterial knitted fabrics").

[0135] The performance results of the fabrics in Examples 1 to 3 are shown in Table 1 below.

[0136] Table 1 - Performance of the fabrics in Examples 1 to 3

[0137]

[0138] Example 4

[0139] S1. Weigh 100 g of titanium dioxide particles (particle size is 0.4 μm, refractive index n = 2.6), and dry them at 150 °C for 24 hours to remove moisture; weigh 1200 g of polylactic acid and dry it under vacuum at 130 °C for 24 h;

[0140] S2. Put the dried titanium dioxide particles and polylactic acid into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, carry out vacuum drying at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a composite multi-material masterbatch, where the mass content of titanium dioxide is 7.69%;

[0141] S3. Weigh 400 g of flaky hexagonal boron nitride (particle size is 0.2 μm), and dry it at 100 °C for 24 hours to remove moisture; weigh 1000 g of polylactic acid and dry it under vacuum at 130 °C for 24 h;

[0142] S4. Put the dried flaky hexagonal boron nitride and polylactic acid into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, carry out vacuum drying at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a composite thermal conductive material masterbatch, where the mass content of flaky hexagonal boron nitride is 28.57%;

[0143] S5. After placing the composite multi-material masterbatch in S2 in a room-temperature and well-ventilated environment for 5 h, carry out vacuum drying at 130 °C for more than 24 h;

[0144] Put the dried composite multi-material masterbatch into a melt spinning machine, heat and melt it at 205 °C, and extrude it through a circular spinneret hole to form a melt stream, and obtain primary drawn filaments at a winding speed of 600 m / min;

[0145] S6. Carry out heating and drawing of the primary drawn filaments in S5 along the filament direction, set the temperatures of two heating rollers to 80 °C and 130 °C respectively, set the feeding and winding speeds to 100 m / min and 300 m / min respectively, and draw the primary drawn filaments by 3 times to obtain the first passive cooling optical metamaterial fiber;

[0146] S7. After placing the composite thermal conductive material masterbatch in S4 in a room-temperature and well-ventilated environment for 5 h, carry out vacuum drying at 130 °C for more than 24 h;

[0147] Put the dried composite thermal conductive material masterbatch into a melt spinning machine, heat and melt it at 205°C, and extrude it through a circular spinneret to form a melt stream, and obtain the primary drawn filament at a winding speed of 600 m / min;

[0148] S8. Stretch the primary drawn filament in S7 along the filament direction, set the temperatures of two heating rollers to 80°C and 130°C respectively, set the feeding and winding speeds to 100 m / min and 300 m / min respectively, and stretch the primary drawn filament by 3 times to obtain the second passive cooling optical metamaterial fiber.

[0149] After cutting the above-mentioned first passive cooling optical metamaterial fiber and the second passive cooling optical metamaterial fiber, a passive cooling optical metamaterial yarn with a coated structure is prepared through the processes of opening, carding, drawing, roving and spinning. The outer layer is formed by the first passive cooling optical metamaterial fibers holding each other, and the inner layer is formed by the second passive cooling optical metamaterial fibers holding each other (as Figure 2 shown).

[0150] Figure 2 The yarn in the figure includes an inner layer and an outer layer. The inner layer is formed by a plurality of second passive cooling optical metamaterial fibers 3 holding each other. The outer layer is arranged circumferentially along the outer periphery of the inner layer, and the outer layer is formed by the first passive cooling optical metamaterial fibers 4 holding each other.

[0151] Finally, conduct the organizational structure design and matching of the above-mentioned optical metamaterial yarn, and obtain a passive cooling optical metamaterial fabric with a single-sided multi-functional hierarchical structure design after steaming, sizing, warping, drawing-in, weaving and desizing. The fabric is composed of circular passive cooling optical metamaterial yarns and has high reflectivity in the solar light band (0.3 - 2.5 μm). A passive cooling optical metamaterial fabric with a multi-material multi-functional hierarchical structure design is obtained. By adjusting its weaving warp and weft densities, the warp density is 141 per 5 cm and the weft density is 90 per 5 cm.

[0152] Example 5

[0153] S1. Weigh 100 g of titanium dioxide particles (particle size of 0.4 μm, refractive index n = 2.6), and dry them at 150°C for 24 hours to remove moisture; weigh 1200 g of polylactic acid and vacuum dry it at 130°C for 24 h;

[0154] S2. Put the dried titanium dioxide particles and polylactic acid into a twin-screw extruder, conduct melt extrusion at 200 °C, cool with water, and send it to a cutting machine for pelletizing to obtain a preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, conduct vacuum drying at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, conduct secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a composite multi-material masterbatch, where the mass content of titanium dioxide is 7.69%;

[0155] S3. Weigh 100 g of flaky hexagonal boron nitride (particle size of 0.2 μm) and dry it at 100 °C for 24 hours to remove moisture; weigh 1000 g of polylactic acid and conduct vacuum drying at 130 °C for 24 h;

[0156] S4. Put the dried flaky hexagonal boron nitride and polylactic acid into a twin-screw extruder, conduct melt extrusion at 200 °C, cool with water, and send it to a cutting machine for pelletizing to obtain a preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, conduct vacuum drying at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, conduct secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a composite thermally conductive material masterbatch, where the mass content of flaky hexagonal boron nitride is 9.09%;

[0157] S5. After placing the composite multi-material masterbatch in S2 in a room-temperature and well-ventilated environment for 5 h, conduct vacuum drying at 130 °C for more than 24 h;

[0158] Put the dried composite multi-material masterbatch into a melt spinning machine, heat and melt it at 205 °C, and eject it through a circular spinneret hole to form a melt stream, and obtain a primary drawn filament at a winding speed of 600 m / min;

[0159] S6. Heat and draw the primary drawn filament in S5 along the filament direction, set the temperatures of two heating rollers to 80 °C and 130 °C respectively, set the filament feeding and winding speeds to 100 m / min and 300 m / min respectively, and draw the primary drawn filament by 3 times to obtain the first passive cooling optical metamaterial fiber;

[0160] S7. After placing the composite thermally conductive material masterbatch in S4 in a room-temperature and well-ventilated environment for 5 h, conduct vacuum drying at 130 °C for more than 24 h;

[0161] Put the dried composite thermally conductive material masterbatch into a melt spinning machine, heat and melt it at 205 °C, and eject it through a circular spinneret hole to form a melt stream, and obtain a primary drawn filament at a winding speed of 600 m / min;

[0162] S8. Heat-draw the nascent filaments in S7 along the filament direction, set the temperatures of two heating rollers to 80 °C and 130 °C respectively, set the feeding and winding speeds to 100 m / min and 300 m / min respectively, and heat-draw the nascent filaments by 3 times to obtain the second passive cooling optical metamaterial fiber.

[0163] After cutting the above first passive cooling optical metamaterial fiber and second passive cooling optical metamaterial fiber, the passive cooling optical metamaterial yarn with a coated structure is prepared through the processes of opening, carding, drawing, roving, and spinning. The outer layer is formed by the short fibers of the first passive cooling optical metamaterial fiber holding each other, and the inner layer is formed by the short fibers of the second passive cooling optical metamaterial fiber holding each other.

[0164] Finally, conduct the organizational structure design and matching on the above optical metamaterial yarn, and obtain the passive cooling optical metamaterial fabric with a single-sided multi-functional hierarchical structure design after steaming, sizing, warping, drawing-in, weaving, and desizing. This fabric is composed of circular passive cooling optical metamaterial yarns and has high reflectivity in the solar wavelength band (0.3 - 2.5 μm). Obtain the passive cooling optical metamaterial fabric with a multi-material multi-functional hierarchical structure design. By adjusting its weaving warp and weft densities, make the warp density 102 per 5 cm and the weft density 66 per 5 cm.

[0165] Example 6

[0166] S1. Weigh 100 g of titanium dioxide particles (particle size 0.4 μm, refractive index n = 2.6), and dry them at 150 °C for 24 hours to remove moisture; weigh 1200 g of polylactic acid and vacuum dry it at 130 °C for 24 h;

[0167] S2. Put the dried titanium dioxide particles and polylactic acid into a twin-screw extruder, conduct melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; place the preliminary multi-material masterbatch in a room-temperature and well-ventilated environment for 5 h, and then conduct vacuum drying at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, conduct secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain the composite multi-material masterbatch, where the mass content of titanium dioxide is 7.69%;

[0168] S3. Weigh 200 g of flaky hexagonal boron nitride (particle size 0.2 μm), and dry it at 100 °C for 24 hours to remove moisture; weigh 1000 g of polylactic acid and vacuum dry it at 130 °C for 24 h;

[0169] S4. Put the dried flaky hexagonal boron nitride and polylactic acid into a twin-screw extruder, melt-extrude at 200°C, water-cool, and send to a cutting machine for pelletizing to obtain a preliminary multi-material masterbatch; place the preliminary multi-material masterbatch in a ventilated environment at room temperature for 5 hours, and then vacuum-dry it at 130°C for 24 hours; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, melt-extrude at 205°C for a second time, water-cool, and pelletize to finally obtain a composite thermal conductive material masterbatch, wherein the mass content of flaky hexagonal boron nitride is 16.66%;

[0170] S5, placing the composite multi-material masterbatch in S2 under ventilation at room temperature for 5 hours, and then vacuum drying at 130°C for more than 24 hours;

[0171] The dried composite multi-material masterbatch was put into a melt spinning machine, heated and melted at 205°C, and ejected through a circular spinneret hole to form a melt stream, and a primary filament was obtained at a winding speed of 600 m / min;

[0172] S6, heating and stretching the nascent filaments in S5 along the filament direction, setting the temperatures of the two heating rollers to 80° C. and 130° C. respectively, setting the unwinding and winding speeds to 100 m / min and 300 m / min respectively, so that the nascent filaments are heated and stretched 3 times, thereby obtaining the first passive cooling optical metamaterial fiber;

[0173] S7, placing the composite thermal conductive material masterbatch in S4 under ventilation at room temperature for 5 hours, and then vacuum drying at 130° C. for more than 24 hours;

[0174] The dried composite thermal conductive material masterbatch is put into a melt spinning machine, heated and melted at 205°C, and ejected through a circular spinneret hole to form a melt stream, and a primary filament is obtained at a winding speed of 600m / min;

[0175] S8, heating and stretching the nascent filaments in S7 along the filament direction, setting the temperatures of the two heating rollers to 80°C and 130°C respectively, setting the unwinding and winding speeds to 100m / min and 300m / min respectively, so that the nascent filaments are heated and stretched 3 times, thereby obtaining a second passive cooling optical metamaterial fiber.

[0176] After the first passive cooling optical metamaterial fiber and the second passive cooling optical metamaterial fiber are cut, the passive cooling optical metamaterial yarn with a coating structure is obtained through opening, combing, drawing, roving and spinning processes, wherein the outer layer is formed by the first passive cooling optical metamaterial fiber staple fibers being mutually embraced, and the inner layer is formed by the second passive cooling optical metamaterial fiber staple fibers being mutually embraced.

[0177] Finally, the above optical metamaterial yarns are subjected to organizational structure design and matching, and after steaming, sizing, warping, drawing-in, weaving, and desizing, a passive cooling optical metamaterial fabric with a single-sided multi-functional hierarchical structure design is obtained. This fabric is composed of circular passive cooling optical metamaterial yarns and has high reflectivity in the sunlight band (0.3 - 2.5 μm). A passive cooling optical metamaterial fabric with a multi-material multi-functional hierarchical structure design is obtained. By adjusting its weaving warp and weft densities, the warp density is 132 threads / 5 cm and the weft density is 81 threads / 5 cm.

[0178] The performances of the passive cooling optical metamaterial fabrics in Examples 4 - 6 are shown in Table 2 below.

[0179] Table 2 - Performances of the passive cooling optical metamaterial fabrics in Examples 4 - 6

[0180]

[0181] Example 7

[0182] S1. Weigh 200 g of titanium dioxide particles (particle size is 0.3 μm, refractive index n = 2.5), and dry them at 150 °C for 24 hours to remove moisture; weigh 1200 g of polylactic acid and vacuum-dry it at 130 °C for 24 h;

[0183] S2. Put the dried titanium dioxide particles and polylactic acid into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature ventilated environment for 5 h, vacuum-dry it at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a composite multi-material masterbatch, where the mass content of titanium dioxide is 14.28%;

[0184] S3. Weigh 50 g of jade powder and 60 g of silver nanoparticles (particle size is 0.4 μm), and dry them at 100 °C for 24 hours to remove moisture; weigh 1000 g of polylactic acid and vacuum-dry it at 130 °C for 24 h;

[0185] S4. Put the dried jade powder and silver nanoparticles into a twin-screw extruder, carry out melt extrusion at 200 °C, cool with water, and send them to a cutting machine for pelletizing to obtain preliminary multi-material masterbatch; after placing the preliminary multi-material masterbatch in a room-temperature ventilated environment for 5 h, vacuum-dry it at 130 °C for 24 h; after drying, put the preliminary multi-material masterbatch into the twin-screw extruder again, carry out secondary melt extrusion, water cooling, and pelletizing at 205 °C to finally obtain a composite functional material masterbatch, where the mass content of jade powder is 4.50% and the mass content of silver nanoparticles is 5.40%;

[0186] S5. After placing the composite multi-material masterbatch in S2 in a room-temperature and well-ventilated environment for 5 h, vacuum dry it at 130 °C for more than 24 h;

[0187] Put the dried composite multi-material masterbatch into a melt spinning machine. Heat and melt it at 205 °C, and extrude it through a circular spinneret to form a melt stream. Obtain the as-grown filament at a winding speed of 600 m / min;

[0188] S6. Heat and draw the as-grown filament in S5 along the filament direction. Set the temperatures of two heating rollers to 80 °C and 130 °C respectively, and set the filament feeding and winding speeds to 100 m / min and 300 m / min respectively, so that the as-grown filament is heated and drawn 3 times to obtain the first passive cooling optical metamaterial fiber. The morphology of this fiber is as Figure 3 shown. Its fineness is about 12.8 μm, and a large number of titanium dioxide nanoparticles are evenly distributed on its surface (as Figure 4 shown);

[0189] S7. After placing the composite functional material masterbatch in S4 in a room-temperature and well-ventilated environment for 5 h, vacuum dry it at 130 °C for more than 24 h;

[0190] Put the dried composite heat-conducting material masterbatch into a melt spinning machine. Heat and melt it at 205 °C, and extrude it through a circular spinneret to form a melt stream. Obtain the as-grown filament at a winding speed of 600 m / min;

[0191] S8. Heat and draw the as-grown filament in S7 along the filament direction. Set the temperatures of two heating rollers to 80 °C and 130 °C respectively, and set the filament feeding and winding speeds to 100 m / min and 300 m / min respectively, so that the as-grown filament is heated and drawn 3 times to obtain the second passive cooling optical metamaterial fiber.

[0192] After cutting the above-mentioned first passive cooling optical metamaterial fiber and the second passive cooling optical metamaterial fiber, make a passive cooling optical metamaterial yarn with a coated structure through the processes of opening, carding, drawing, roving and spinning. By adjusting its weaving warp and weft densities, make the warp density 131 threads / 5 cm and the weft density 82 threads / 5 cm.

[0193] Finally, conduct the organizational structure design and matching on the above-mentioned optical metamaterial yarn. After steaming, sizing, warping, drawing-in, weaving, and desizing, obtain an upper-layer optical high-reflection layer fabric (that is, after the yarn prepared from the first passive cooling optical metamaterial fiber is woven, an optical high-reflection layer fabric is obtained), and a lower-layer cool-sensation antibacterial fabric (that is, after the yarn prepared from the second passive cooling optical metamaterial fiber is woven, a cool-sensation antibacterial fabric is obtained) (as Figure 5as shown); the fabric has integrated functions of cool feeling, antibacterial property and passive cooling, which will effectively improve people's thermal comfort.

[0194] Figure 5 FIG. 4 is a schematic structural view of the above-mentioned fabric, which includes an optically highly reflective layer fabric 6 and a cool feeling antibacterial fabric 5 that are mutually adhered.

[0195] The breaking strength of the obtained fabric is 159 N / 5 cm (reference standard: ISO 13934-1 "Textiles - Tensile properties of fabrics"), the tearing strength is 12.8 N (reference standard: ISO 13937-1-2000 "Textiles - Tear properties of fabrics - Part 1: Determination of tear strength by the pendulum method"), the abrasion resistance is 4480 times (reference standard: ISO12947-1998 "Textiles - Determination of fabric abrasion resistance using the Martindale method"), the air permeability is 130 mm / s (reference standard: ISO 9237-1995 "Determination of air permeability of fabrics"), the solar band reflectivity is 75%, the antibacterial rate against Staphylococcus aureus is 74.5%, the antibacterial rate against Escherichia coli is 72.1%, and the antibacterial rate against Candida albicans is 70.7% (reference standard: FZ / T 73023-2006 "Antibacterial knitted goods").

[0196] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a multifunctional passive cooling optical metamaterial fiber, characterized in that It includes the following steps: Melting and extruding high refractive index inorganic micro-nano particles and / or micro-nano functional materials, and polymer base materials to obtain a composite multi-material masterbatch; Heating and melting the composite multi-material masterbatch, extruding it through a spinneret orifice to form a melt stream, and winding it to obtain a primary optical metamaterial filament; Heating and drawing the primary optical metamaterial filament to obtain a passive cooling optical metamaterial fiber; The refractive index n of the high refractive index inorganic micro-nano particles ≥ 2.5; The particle size of the high refractive index inorganic micro-nano particles is 50 - 800 nm; The particle size of the micro-nano functional materials is 50 - 800 nm.

2. The preparation method of the multifunctional passive cooling optical metamaterial fiber according to claim 1, wherein, The high refractive index inorganic micro-nano particles include at least one of titanium dioxide, zinc sulfide, silicon carbide, silicon nitride, zinc oxide, boron nitride, aluminum silicate, barium sulfate, calcium carbonate, magnesium oxide, aluminum oxide, magnesium carbonate, barium carbonate, calcium sulfate; And / or, the micro-nano functional materials include at least one of hexagonal boron nitride, hexagonal silicon carbide, silver nanoparticles, copper nanoparticles, gold nanoparticles, ZnO, La2O3 nanoparticles, CeO2 nanoparticles, V2O5 nanoparticles, CuO nanoparticles, mica flakes, graphene flakes, flaky carbon powder, flake graphite, exfoliated graphite, expanded graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, fullerenes, carbon nanofibers, fibrous carbon powder, tungsten oxide, jade powder, medical stone powder, molybdenum disulfide, copper sulfide, copper nanowires, silver nanowires, boron nitride nanotubes, silicon carbide nanotubes, silicon carbide whiskers, iron oxide, TiO2, metal carbides and / or nitrides, metal-organic framework compounds, peroxidase derivatives; And / or, the polymer base materials include at least one of polylactic acid, polyethylene terephthalate, polyvinylidene fluoride, polymethyl methacrylate, polypropylene, polyvinyl chloride, polystyrene, polyester and sodium m-phthalate sulfonate copolymer, acrylate copolymer, polyethylene glycol, polytrimethylene terephthalate, polyvinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol, polyurethane, polyacrylonitrile, cycloolefin copolymer, polycarbonate, acrylonitrile-butadiene-styrene, polyoxymethylene, polyphenylene ether, polyimide, vinyl acetate resin, polyvinyl formal, polyvinyl acetate and polyvinyl acetal.

3. The preparation method of the multifunctional passive cooling optical metamaterial fiber according to claim 1, characterized in that, The structure of the passive cooling optical metamaterial fiber includes any one of a core-shell structure, a cylindrical structure, a hollow cylindrical structure, and a sea-island structure.

4. The preparation method of the multifunctional passive cooling optical metamaterial fiber according to claim 3, characterized in that, The structure of the passive cooling optical metamaterial fiber is a core-shell structure, and the preparation method of the passive cooling optical metamaterial fiber includes the following steps: Melting and extruding high refractive index inorganic micro-nano particles or micro-nano functional materials, and polymer base materials to obtain a skin-layer composite multi-material masterbatch; Melting and extruding high refractive index inorganic micro-nano particles or micro-nano functional materials, and polymer base materials to obtain a core-layer composite multi-material masterbatch; Respectively putting the skin-layer composite multi-material masterbatch and the core-layer composite multi-material masterbatch into two feeding ports of a melt composite spinning machine, extruding them through a core-shell structure spinneret orifice to form a melt stream, and winding it to obtain a core-shell structure primary optical metamaterial filament; Heat-draw the as-spun optical metamaterial filament with a core-shell structure to obtain a passive cooling optical metamaterial fiber with a core-shell structure; The mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the skin-layer composite multi-material masterbatch is 1-40%; The mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the core-layer composite multi-material masterbatch is 1-40%.

5. The preparation method of the multifunctional passive cooling optical metamaterial fiber according to claim 3, characterized in that, The structure of the passive cooling optical metamaterial fiber is a cylinder structure, and the preparation method of the passive cooling optical metamaterial fiber includes the following steps: Melt-extrude the high refractive index inorganic micro-nano particles or micro-nano functional materials and the polymer base material to obtain a composite multi-material masterbatch; Heat-melt the composite multi-material masterbatch, extrude it through a circular spinneret hole to form a melt stream, and wind it to obtain an as-spun optical metamaterial filament; Heat-draw the as-spun optical metamaterial filament to obtain a passive cooling optical metamaterial fiber with a cylinder structure; The mass fraction of the high refractive index inorganic micro-nano particles or micro-nano functional materials in the composite multi-material masterbatch is 1-40%.

6. The preparation method of the multifunctional passive cooling optical metamaterial fiber according to any one of claims 1 to 5, characterized in that, The winding speed is 200 m / min to 1200 m / min; The heat-drawing of the as-spun optical metamaterial filament specifically includes: The as-spun optical metamaterial filament sequentially passes through a first heating roller and a second heating roller along the filament direction and is stretched. Among them, the temperature of the first heating roller is 70-90 °C, the temperature of the second heating roller is 120-140 °C, the speed of the as-spun optical metamaterial filament passing through the first heating roller is 90-110 m / min, and the speed of the as-spun optical metamaterial filament passing through the second heating roller is 290-310 m / min; The draw ratio is 1-4 times.

7. The preparation method of the multifunctional passive cooling optical metamaterial fiber according to claim 1, characterized in that, The diameter of the passive cooling optical metamaterial fiber is 10-100 μm.

8. An optical metamaterial yarn, characterized in that, The passive cooling optical metamaterial fiber is obtained by spinning the fiber prepared by the preparation method according to any one of claims 1-7.

9. The optical metamaterial yarn according to claim 8, characterized in that The structure of the optical metamaterial yarn is any one of a single yarn structure, a double-twist yarn structure, a multi-twist yarn structure, a complex-twist ply yarn structure, and a core-spun yarn structure.

10. An optical metamaterial fabric, characterized in that, The optical metamaterial fabric is obtained by weaving the optical metamaterial yarn according to any one of claims 8-9.

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