All-spectrum high-reflective thermal management fabric and preparation method and application thereof

Abstract

The present application relates to the technical field of thermal management fibers, in particular to a full-spectrum high-reflective thermal management fabric, a preparation method and application thereof.The full-spectrum high-reflective thermal management fabric comprises a composite bottom fiber film and a surface fiber film.The bottom fiber film comprises a first fiber film formed by a mid-infrared high-emission material, and the surface fiber film comprises a second fiber film formed by a solar high-reflective mid-infrared high-transmission material;the fabric simultaneously utilizes the bottom high-emission material, the surface high-solar-reflective and high-mid-infrared-transmission layer prepared by the high-reflective material coated between the two, and the composite bottom inner and outer double-sided heterogeneous material to achieve the required performance.

Description

Technical Field

[0001] This invention relates to the field of thermal management fiber technology, specifically to a full-spectrum high-reflectivity thermal management fabric, its preparation method, and its application. Background Technology

[0002] As the energy crisis and global warming become increasingly severe, resulting in enormous economic losses and serious climate problems, extreme weather events such as extreme heat and cold are becoming more intense and frequent. Developing efficient and energy-saving personal and building thermal management technologies is of great significance for improving human comfort in extreme environments (such as extreme heat and drought or high temperature and humidity) and reducing the enormous energy consumption for temperature control in the building sector.

[0003] Traditional thermal management systems offer excellent heating and cooling performance, but they consume significant amounts of energy and cannot provide timely and effective temperature control, especially in outdoor environments. Personalized thermal management, on the other hand, provides heating or cooling only to the individual and their localized environment, avoiding the waste of heat and cooling across the entire building. It offers a personalized and efficient solution. While achieving passive thermal regulation, it reduces reliance on inefficient temperature control methods like air conditioning, thus meeting individualized thermal comfort needs more energy-efficiently and economically.

[0004] Radiative cooling is a physical mechanism by which ground-based objects transfer heat to outer space through windows in the mid-infrared band of the atmosphere via radiation, thereby reducing their own temperature. Under solar irradiation, two main radiation bands are involved: one is the solar band (0.25-2.5μm), where effective radiative cooling requires high solar reflectivity to reduce solar radiation heat input; the other is the mid-infrared band (2.5-20μm). The radiation characteristics of materials in the mid-infrared band can be categorized as follows: 1. High transmittance: High transmittance in the mid-infrared band, facilitating heat radiation transmission from objects; 2. High emissivity: High emissivity in the mid-infrared band, allowing heat to radiate through the material surface; 3. Selective transmittance: High emissivity in the atmospheric window (8-13μm) band and high transmittance in the non-atmospheric window band; 4. Selective emission: High emissivity in the atmospheric window (8-13μm) band, with minimal absorption (high reflection) of radiated heat from the surrounding environment in the non-atmospheric infrared window region, suitable for applications where vertical use is significantly affected by surrounding high-temperature buildings and the ground under urban heat island effects; 5. High reflectivity: High reflectivity in the mid-infrared band, suitable for radiative heat insulation of people, buildings, or equipment. Of these materials, the first three radiation characteristics are suitable for applications in indoor or outdoor environments with lower ambient temperatures.

[0005] Currently, cooling fabrics with the first four radiation characteristics have been studied and applied to some extent. Infrared high reflectivity fabrics, due to their low infrared emissivity, are typically used for human body insulation. In the solar radiation band, they tend to have high absorption to absorb as much solar radiation heat as possible to enhance insulation performance. Therefore, full-spectrum high reflectivity cooling fabrics have not been fully studied. In addition, it is difficult to simultaneously satisfy the high reflectivity properties of fabrics in both the solar band and the mid-infrared band. This is mainly because micro-nano particles and polymers with high solar reflectivity have strong absorption in the mid-infrared band. The content of micro-nano particles and the thickness of porous polymers are important prerequisites for obtaining high solar reflectivity performance, but high content and thickness will inevitably enhance the infrared absorption of the material, and increasing the thickness will also sacrifice the flexibility of the material. However, in extreme high-temperature environments, the human body not only needs high solar reflectivity to minimize solar radiation heat input, but also receives radiative heat input from surrounding high-temperature buildings and the ground in the mid-infrared band, thus requiring high reflectivity to reduce mid-infrared radiation heat input. Therefore, fabrics that balance high solar reflectivity and mid-infrared reflectivity are the basic conditions for achieving radiative heat insulation between the human body / building and the external high-temperature environment in extreme high-temperature environments. Furthermore, flexibility, strength, and durability are necessary conditions for its application, but existing materials cannot meet these requirements simultaneously.

[0006] Therefore, there is an urgent need in this field to develop a novel thermal management fabric. This fabric should possess excellent and controllable full-spectrum high reflectivity, effectively blocking solar radiation heat and achieving radiative insulation or low emission from the external thermal environment, thereby enabling energy-efficient thermal management for individuals or buildings in extreme environments. Simultaneously, its preparation method should be simple, economical, and environmentally friendly, and compatible with existing textile industries. While maintaining excellent thermal management performance, it must also possess good wearing comfort and environmental durability to expand its applications in outdoor clothing, building energy conservation, automotive interiors, and other fields. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to provide a full-spectrum high reflectance thermal management fabric, which has excellent and controllable full-spectrum high reflectance characteristics, can effectively block solar radiation heat, and can achieve radiation insulation or low emission to the external thermal environment, thereby realizing thermal management for extreme environments. Another technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned full-spectrum high reflectance thermal management fabric.

[0008] To address the aforementioned technical problems, this invention provides a full-spectrum high-reflectivity thermal management fabric, the fabric comprising a composite bottom fiber membrane and a surface fiber membrane; wherein, The underlying fiber membrane includes a first fiber membrane formed of a mid-infrared high-emissivity material; The surface fiber membrane includes a second fiber membrane formed of a solar high reflectance and mid-infrared high transmittance material; The bottom fiber membrane is coated with an infrared high reflectivity coating on the side of the top fiber membrane that is close to the bottom fiber membrane. The infrared high reflectivity coating is formed of an infrared high reflectivity material; The mid-infrared high-emissivity material includes at least one of cellulose acetate (CA), thermoplastic polyurethane elastomer (TPU), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polylactic acid (PLA), polyvinyl alcohol (PVA), polyethylene oxide (PEO), or polyoxymethylene (POM). The solar high reflectance and high infrared transmittance material includes at least one of polyacrylonitrile (PAN) or polyamide fiber (PA6); The infrared high reflectivity material includes at least one of aluminum (Al), silver (Ag), copper (Cu), silver nanowires (AgNWs), or two-dimensional transition metal carbon / nitrides (MXene).

[0009] Specifically, in the full-spectrum high-reflectivity heat management fabric, the thickness of the first fiber membrane in the bottom fiber membrane is 100-500 μm.

[0010] The thickness of the first fiber membrane is 100-500 μm, and there are no special requirements for the pore size. The high radiation optical properties of the material itself are mainly used for thermal management optimization.

[0011] Specifically, in the full-spectrum high-reflectivity thermal management fabric, the molecular weight of the solar high-reflectivity mid-infrared high-transmittance material in the surface fiber membrane is 40,000 to 150,000.

[0012] Specifically, in the full-spectrum high-reflectivity heat management fabric, the surface fiber membrane contains: The thickness of the second fiber membrane is 100-200 μm; and / or, The fiber diameter of the second fiber membrane is 0.2-2 μm.

[0013] In some specific embodiments, the second fiber membrane is preferably a polyacrylonitrile fiber membrane, and the molecular weight of the polyacrylonitrile is preferably 40,000 to 150,000.

[0014] Specifically, the full-spectrum high-reflectivity thermal management fabric has an infrared high-reflectivity coating with a thickness of 5-30 μm.

[0015] The infrared high-reflectivity coating can be first sprayed onto the surface of the first fiber membrane, utilizing its smooth surface to form a high-reflectivity layer. The coating thickness is approximately in the range of 5-30 μm, which can effectively achieve high reflectivity. Alternatively, it can be sprayed onto the surface of the second fiber membrane, utilizing its smooth surface to form a high-reflectivity layer. The coating thickness is also in the range of 5-30 μm, which can effectively achieve high reflectivity.

[0016] In some specific embodiments, the thickness of the polyacrylonitrile fiber membrane is 100-200 μm. Generally, if the thickness is too thin, the solar reflectivity is insufficient; if the thickness is too thick, it will enhance infrared absorption, resulting in insufficient mid-infrared transmittance. By controlling the internal fiber diameter of the membrane, the membrane diameter is mainly between 0.2-2 μm, to achieve high solar reflectivity through strong Mie scattering of sunlight (0.5-2.5 μm), while maintaining high transmittance of mid-infrared light by staying away from the mid-infrared band (2.5-25 μm).

[0017] In some specific embodiments, the polyacrylonitrile fiber membrane has a fiber diameter of 0.2-2 μm. The fiber membrane itself has a pore size in the range of 0.2-2 μm, resulting in strong Mie scattering of sunlight (0.25-2.5 μm).

[0018] In some specific embodiments, the second fiber membrane is preferably a polyacrylonitrile fiber membrane. By optimizing the fiber size inside the fiber membrane, it has been surprisingly found that it can achieve ideal optical performance with both high solar reflectance and high infrared transmittance, and has ideal application advantages in terms of high solar reflectance and high infrared transmittance.

[0019] In some specific embodiments, when selecting a polyacrylonitrile fiber membrane as the functional membrane layer, the main focus is on the optical properties of the polyacrylonitrile fiber membrane, which requires a material that transmits mid-infrared light while also reflecting sunlight. The second fiber membrane is based on PAN material and combines the design of fiber diameter and membrane size to achieve the above-mentioned advantages.

[0020] This invention also discloses a method for preparing the full-spectrum high-reflectance thermal management fabric, comprising the following steps: (1) Take the mid-infrared high-emissivity material and add it to the first spinning solvent for the first mixing to prepare the first spinning solution; use the first electrospinning process to process the first fiber membrane of the required size; (2) Take the infrared high reflectivity material, add the first binder and the first dispersing solvent to make a second mixture, and prepare a coating liquid; spray it on the surface of the first fiber membrane to form the infrared high reflectivity coating; (3) Take the solar high reflectance and high infrared transmittance material and add it to the second spinning solvent for a third mixing to prepare the second spinning solution; use the second electrospinning process to process the second fiber membrane of the required size on the surface of the first coating to obtain the second fiber membrane. or, (1) Take the solar high reflectance and high infrared transmittance material and add it to the second spinning solvent for the third mixing to prepare the second spinning solution; use the second electrospinning process to process the second fiber membrane of the required size; (2) Take the infrared high reflectivity material, add the first binder and the first dispersing solvent to make a second mixture, and prepare a coating liquid; spray it on the surface of the second fiber membrane to form the infrared high reflectivity coating; (3) Take the mid-infrared high-emission material and add it to the first spinning solvent for the first mixing to prepare the first spinning solution; use the first electrospinning process to process the first fiber membrane of the required size on the surface of the second coating.

[0021] Specifically, the preparation method of the full-spectrum high-reflectance thermal management fabric is as follows: In the first spinning solution, the mass ratio of the mid-infrared high-emissivity material is 8-12 wt%; and / or, The first spinning solvent includes N,N-dimethylformamide; and / or, The mixing speed in the first mixing step is 400-600 rpm; and / or, The mixing time for the first mixing step is 6-8 hours; and / or, The receiving distance for the first electrospinning process is 12-18 cm; and / or, The spinning voltage of the first electrospinning process is 18-20kV.

[0022] Specifically, the preparation method of the full-spectrum high-reflectance thermal management fabric is as follows: In the coating liquid, the mass content of the infrared high reflectivity material is 2-15 wt%; and / or, In the coating liquid, the first adhesive comprises acrylic resin; and / or, The first adhesive is based on the infrared high reflectance material having a mass content of 20-50 wt%; and / or, The first dispersing solvent includes tetrachloroethylene; The mixing speed in the second mixing step is 200-600 rpm; and / or, The mixing time for the second mixing step is 4-6 hours; and / or, In the spraying step, the spraying pressure is 15-50 psi, the nozzle diameter is 0.3-0.8 mm, the spraying distance is 5-10 cm, and the sprayed surface density is 250-550 g / m³. 2 .

[0023] Specifically, the preparation method of the full-spectrum high-reflectance thermal management fabric is as follows: In the second spinning solution, the mass ratio of the solar high reflectance and high infrared transmittance material is 8-12 wt%; and / or, The second spinning solvent includes N,N-dimethylformamide; generally, if the concentration of the spinning solution is too low, spinning is difficult, while if the concentration is too high, infrared absorption will increase; and / or, The mixing speed in the third mixing step is 400-600 rpm; and / or, The mixing temperature in the third mixing step is 50-60℃; and / or, The mixing time for the third mixing step is 6-8 hours; and / or, The receiving distance for the second electrospinning process is 12-18 cm; and / or, The spinning voltage of the second electrospinning process is 18-20kV.

[0024] In some specific embodiments, the method further includes a step of drying the first fiber membrane and / or the second fiber membrane, including but not limited to natural drying or high-temperature (50-80°C) drying for at least 24 hours.

[0025] This invention also discloses the application of the full-spectrum high-reflectivity thermal management fabric or the full-spectrum high-reflectivity thermal management fabric prepared by the method in the fields of outdoor clothing, building energy conservation, and automotive interiors, including but not limited to extreme environment outdoor equipment, high-temperature work clothes, tents, sunshades, building envelopes, outdoor infrastructure enclosures, and automotive interior materials.

[0026] The full-spectrum high-reflectivity thermal management fabric of this invention comprises a composite bottom fiber membrane and a top fiber membrane. The bottom fiber membrane includes a first fiber membrane formed of a mid-infrared high-emissivity material, and the top fiber membrane includes a second fiber membrane formed of a solar high-reflectivity mid-infrared high-transmittance material. The fabric simultaneously utilizes a bottom high-emissivity material, a top layer with high solar reflection and mid-infrared transmittance, and a high-reflectivity material coated between the two, combining materials with anisotropic properties on both the inner and outer sides to achieve the desired performance.

[0027] The full-spectrum high-reflectivity thermal management fabric of the present invention includes a bottom fiber membrane comprising a first fiber membrane formed of a mid-infrared high-emissivity material; the dense and flat surface of the fiber membrane is conducive to improving mid-infrared reflection, and the high solar reflection and high-mid-infrared transmittance of the surface layer allow for the realization of full-spectrum high-reflectivity characteristics with both high solar reflection and high-mid-infrared reflection.

[0028] The full-spectrum high-reflectivity thermal management fabric of this invention has an infrared high-reflectivity coating applied to the side of the bottom fiber membrane adjacent to the surface fiber membrane, or the side of the surface fiber membrane adjacent to the bottom fiber membrane; the infrared high-reflectivity coating is formed of an infrared high-reflectivity material. The infrared high-reflectivity coating further ensures the thermal management performance between the bottom fiber membrane and the surface fiber membrane.

[0029] The full-spectrum high-reflectivity thermal management fabric of this invention includes a surface fiber membrane comprising a second fiber membrane formed of a solar high-reflectivity, mid-infrared high-transmittance material. Through optimization of the fiber membrane size, it was surprisingly discovered that materials such as PAN can achieve ideal optical performance with both high solar reflectivity and high-mid-infrared transmittance. It not only has high solar reflectivity to isolate external solar radiation heat input, but also high mid-infrared transmittance to allow mid-infrared thermal radiation to pass through and be reflected by the underlying high-infrared reflective layer. Thus, it has ideal application advantages in terms of high solar reflectivity and high-mid-infrared transmittance.

[0030] The full-spectrum high-reflectivity thermal management fabric of the present invention has the characteristics of mid-infrared high-emissivity material which is conducive to the radiative heat transfer of the inner layer. Compared with woven fabric, the flat surface of the fiber membrane is conducive to the parallel arrangement of aluminum sheets after spraying, thus having a high mid-infrared reflectivity.

[0031] The full-spectrum high-reflectivity thermal management fabric of this invention, a solar high-reflectivity mid-infrared high-transmittance material, achieves its unique optical properties by constructing micro-nano fibers and pores through electrospinning. Studies show that, compared to composite high-reflectivity particles with high-transmittance films, the presence of high-reflectivity particles causes partial infrared absorption or reflection, affecting mid-to-high infrared transmittance, and dense films have poor air permeability; compared to directly spraying high-reflectivity particles, the composite of a large number of particles also affects mid-to-high infrared transmittance, and the adhesion and durability of the high-reflectivity particles and the influence of adhesives on infrared transmittance must also be considered; compared to porous high-transmittance films, this effectively avoids the significant reduction in strength caused by abundant micro-nano pores.

[0032] The full-spectrum high-reflectivity thermal management fabric of the present invention has a high-infrared emissivity on its inner fiber membrane and a high-infrared reflectivity on its outer fiber membrane while exhibiting high solar reflectivity, thus demonstrating enhanced radiation insulation performance and excellent thermal management effect.

[0033] The full-spectrum high-reflectivity thermal management fabric of the present invention is achieved by using micro-nano fiber membranes and high-reflectivity coatings, and the thickness can be reduced to about 200μm. The material is lightweight and soft, and the coating can enhance the bonding strength of the fiber membrane.

[0034] The full-spectrum high-reflectivity thermal management fabric of the present invention has a first coating on the surface of the first fiber membrane. After spraying Al sheets onto the flat mid-infrared high-emissivity fiber membrane surface, the parallel arrangement of the Al sheets on the surface is facilitated, resulting in a high infrared reflectivity (>90%). Since the top PAN fiber membrane has the characteristics of high solar reflection and high infrared transmittance, the composite fiber membrane with sandwich structure has a high mid-infrared emissivity in the inner layer and a wide-spectrum high reflectivity with both high solar reflection and high infrared reflection on the outer surface.

[0035] The method for preparing the full-spectrum high-reflectivity thermal management fabric described in this invention has a wide range of raw material sources, is suitable for low-cost and large-scale industrialization, has low-cost scalability, and the materials used in the electrospinning process are mature commercial materials with low cost. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the preparation process of the fabric described in this invention; Figure 2 shows the optical properties of the fabric prepared in Example 1; Figure 3 Results of thermal management performance of the fabric prepared in Example 1; Figure 4 The results show the infrared stealth function of the fabric prepared in Example 1. Detailed Implementation

[0038] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0039] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0040] The full-spectrum high-reflectivity thermal management fabric provided in the following embodiments of the present invention comprises a composite bottom fiber membrane and a surface fiber membrane; wherein, The underlying fiber membrane includes a first fiber membrane formed of a mid-infrared high-emissivity material; The surface fiber membrane includes a second fiber membrane formed of a solar high reflectance and mid-infrared high transmittance material; The bottom fiber membrane is coated with an infrared high reflectivity coating on the side adjacent to the top fiber membrane, or the side of the top fiber membrane adjacent to the bottom fiber membrane is coated with an infrared high reflectivity coating; the infrared high reflectivity coating is formed of an infrared high reflectivity material.

[0041] In the following embodiments of the present invention, the infrared high reflectivity coating can be disposed between the bottom fiber membrane and the surface fiber membrane. The performance of the fabric can be achieved regardless of whether it is coated on the bottom fiber membrane or the surface fiber membrane.

[0042] In the following embodiments of the present invention, as an exemplary implementation, the infrared high reflectivity coating is uniformly coated on the surface of the bottom fiber membrane, and the surface fiber membrane is compositely disposed on the side close to the infrared high reflectivity coating.

[0043] In the following embodiments of the present invention, as an exemplary implementation, the method for preparing the full-spectrum high-reflectivity thermal management fabric includes the following steps: (1) Weigh a certain amount of mid-infrared high-emissivity material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 8-12wt%, and treat it at 400-600 rpm for 6-8 hours to obtain the required first spinning solution; use the first electrospinning process, adjust the receiving distance to 12-18cm and the spinning voltage to 18-20kV to prepare a first fiber membrane of a certain thickness, and then dry it naturally or at high temperature (60℃) for 24 hours. (2) Weigh out infrared high reflectivity material and binder-acrylic resin at a mass ratio of 2-15 wt% of the infrared high reflectivity material, and select tetrachloroethylene as the dispersion solvent. After mixing, treat the mixture at 200-600 rpm for 4-6 hours. Spray the mixture onto the surface of the first fiber membrane, controlling the spraying pressure at 15-50 psi, the nozzle diameter at 0.3-0.8 mm, the spraying distance at 5-10 cm, and the spraying surface density at 250-550 g / m³. 2 This forms the desired first coating. (3) Weigh a certain amount of solar high reflectance mid-infrared high transmittance material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 8-12wt%, and treat it at 400-600 rpm and 60℃ for 6-8 hours to obtain the required second spinning solution; adopt the second electrospinning process, adjust the receiving distance to 12-18cm and the spinning voltage to 18-20kv, and continue to prepare a second fiber membrane of a certain thickness on the surface of the first coating side of the first fiber membrane. After natural drying or high temperature (60℃) drying for 24 hours, it is ready.

[0044] Example 1 As attached Figure 1 The flowchart shown illustrates that, in this embodiment, the method for preparing the full-spectrum high-reflectivity thermal management fabric includes the following steps: (1) Weigh a certain amount of cellulose acetate (CA) and solvent N,N-dimethylformamide according to the mass ratio of 10wt% of the spinning polymer, and treat it at 500 rpm for 7 hours to obtain the required first spinning solution; use the first electrospinning process, adjust the receiving distance to 15cm and the spinning voltage to 20kV to prepare a first fiber membrane of a certain thickness, control the thickness of the first fiber membrane to be 300μm, and dry it at high temperature (60℃) for 24 hours. (2) Weigh out 10 wt% infrared high reflectivity material and 35 wt% of the mass of the infrared high reflectivity material as binder-acrylic resin. Select tetrachloroethylene as the dispersion solvent. After mixing, treat at 400 rpm for 5 hours. Spray the mixture onto the surface of the first fiber membrane at a spraying pressure of 20 psi, a nozzle diameter of 0.3 mm, a spraying distance of 5 cm, and a spray surface density of 400 g / m³. 2 This forms the desired first coating. (3) Weigh a certain amount of solar high reflectance mid-infrared high transmittance material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer 10wt%, and treat it at 500 rpm and 60℃ for 7 hours to obtain the required second spinning solution; adopt the second electrospinning process, adjust the receiving distance to 15cm and the spinning voltage to 20kV, and continue to prepare a second fiber membrane of a certain thickness on the surface of the first coating side of the first fiber membrane, and control the thickness of the second fiber membrane to be 200μm and the fiber diameter of the second fiber membrane to be 1μm; after drying at high temperature (60℃) for 24 hours, it is ready.

[0045] Example 2 As attached Figure 1 The flowchart shown illustrates that, in this embodiment, the method for preparing the full-spectrum high-reflectivity thermal management fabric includes the following steps: (1) Weigh a certain amount of mid-infrared high-emissivity material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 8wt%, and treat it at 400 rpm for 8 hours to obtain the required first spinning solution; use the first electrospinning process, adjust the receiving distance to 12cm and the spinning voltage to 20kv to prepare a first fiber membrane of a certain thickness, control the thickness of the first fiber membrane to be 100μm, and dry it at high temperature (60℃) for 24 hours. (2) Weigh out 2 wt% infrared high reflectivity material and 20 wt% of the mass of the infrared high reflectivity material binder-acrylic resin, select tetrachloroethylene as the dispersion solvent, mix them, treat them at 200 rpm for 6 hours, and spray them onto the surface of the first fiber membrane to form the desired first coating. The spraying pressure is 20 psi, the nozzle diameter is 0.3 mm, the spraying distance is 5 cm, and the spraying surface density is 250 g / m³.2 ; (3) Weigh a certain amount of solar high reflectance mid-infrared high transmittance material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 8wt%, and treat it at 400 rpm and 60℃ for 8 hours to obtain the required second spinning solution; adopt the second electrospinning process, adjust the receiving distance to 12cm and the spinning voltage to 20kV, and continue to prepare a second fiber membrane of a certain thickness on the surface of the first coating side of the first fiber membrane, and control the thickness of the second fiber membrane to be 100μm and the fiber diameter of the second fiber membrane to be 0.2μm; after drying at high temperature (60℃) for 24 hours, it is ready.

[0046] Example 3 As attached Figure 1 The flowchart shown illustrates that, in this embodiment, the method for preparing the full-spectrum high-reflectivity thermal management fabric includes the following steps: (1) Weigh a certain amount of mid-infrared high-emissivity material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 12wt%, and treat it at 600 rpm for 6 hours to obtain the required first spinning solution; use the first electrospinning process, adjust the receiving distance to 18cm and the spinning voltage to 18kv to prepare a first fiber membrane of a certain thickness, control the thickness of the first fiber membrane to be 500μm, and dry it at high temperature (60℃) for 24 hours. (2) Weigh out infrared high reflectivity material and binder-acrylic resin at a mass ratio of 15wt% of the infrared high reflectivity material, and select tetrachloroethylene as the dispersion solvent. After mixing, treat the mixture at 600 rpm for 4 hours. Apply the mixture to the surface of the first fiber membrane by first spraying to form the desired first coating. The spraying pressure is 20 psi, the nozzle diameter is 0.3 mm, the spraying distance is 5 cm, and the spraying surface density is 550 g / m³. 2 ; (3) Weigh a certain amount of solar high reflectance mid-infrared high transmittance material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 12wt%. Treat it at 600 rpm and 60℃ for 6 hours to obtain the required second spinning solution. Use the second electrospinning process, adjust the receiving distance to 18cm and the spinning voltage to 18kv, and continue to prepare a second fiber membrane of a certain thickness on the surface of the first coating side of the first fiber membrane. Control the thickness of the second fiber membrane to be 150μm and the fiber diameter of the second fiber membrane to be 2μm. Dry it at high temperature (60℃) for 24 hours.

[0047] Example 4 As attached Figure 1 The flowchart shown illustrates that, in this embodiment, the method for preparing the full-spectrum high-reflectivity thermal management fabric includes the following steps: (1) Weigh a certain amount of mid-infrared high-emissivity material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 10wt%, and treat it at 500 rpm for 8 hours to obtain the required first spinning solution; use the first electrospinning process, adjust the receiving distance to 15cm and the spinning voltage to 20kV to prepare a first fiber membrane of a certain thickness, control the thickness of the first fiber membrane to be 200μm, and dry it at high temperature (60℃) for 24 hours. (2) Weigh out infrared high reflectivity material and binder-acrylic resin at a mass ratio of 5wt% of the infrared high reflectivity material, and select tetrachloroethylene as the dispersion solvent. After mixing, treat the mixture at 400 rpm for 5 hours. Apply the mixture to the surface of the first fiber membrane by first spraying to form the desired first coating. The spraying pressure is 20 psi, the nozzle diameter is 0.5 mm, the spraying distance is 5 cm, and the spraying surface density is 400 g / m². 2 ; (3) Weigh a certain amount of solar high reflectance mid-infrared high transmittance material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer 10wt%, and treat it at 500 rpm and 60℃ for 8 hours to obtain the required second spinning solution; adopt the second electrospinning process, adjust the receiving distance to 15cm and the spinning voltage to 20kV, and continue to prepare a second fiber membrane of a certain thickness on the surface of the first coating side of the first fiber membrane, and control the thickness of the second fiber membrane to be 120μm and the fiber diameter of the second fiber membrane to be 0.5μm; after drying at high temperature (60℃) for 24 hours, it is ready.

[0048] Example 5 As attached Figure 1 The flowchart shown illustrates that, in this embodiment, the method for preparing the full-spectrum high-reflectivity thermal management fabric includes the following steps: (1) Weigh a certain amount of mid-infrared high-emissivity material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer of 10wt%, and treat it at 500 rpm for 8 hours to obtain the required first spinning solution; use the first electrospinning process, adjust the receiving distance to 15cm and the spinning voltage to 20kV to prepare a first fiber membrane of a certain thickness, control the thickness of the first fiber membrane to be 400μm, and dry it at high temperature (60℃) for 24 hours. (2) Weigh out infrared high reflectivity material and binder-acrylic resin at a mass ratio of 12wt% of the infrared high reflectivity material, and select tetrachloroethylene as the dispersion solvent. After mixing, treat the mixture at 400 rpm for 5 hours. Apply the mixture to the surface of the first fiber membrane by first spraying to form the desired first coating. The spraying pressure is 20 psi, the nozzle diameter is 0.3 mm, the spraying distance is 10 cm, and the spraying surface density is 400 g / m³. 2 ; (3) Weigh a certain amount of solar high reflectance mid-infrared high transmittance material and solvent N,N-dimethylformamide according to the mass ratio of spinning polymer 10wt%, and treat it at 500 rpm and 60℃ for 6 hours to obtain the required second spinning solution; adopt the second electrospinning process, adjust the receiving distance to 15cm and the spinning voltage to 20kV, and continue to prepare a second fiber membrane of a certain thickness on the surface of the first coating side of the first fiber membrane, and control the thickness of the second fiber membrane to be 180μm and the fiber diameter of the second fiber membrane to be 1.5μm; after drying at high temperature (60℃) for 24 hours, it is ready.

[0049] Example 6 The preparation method of the full-spectrum high reflectance thermal management fabric in this embodiment is the same as that in Embodiment 1, except that the mid-infrared high-emissivity material in the first fiber membrane is selected as thermoplastic polyurethane elastomer (TPU).

[0050] Example 7 The preparation method of the full-spectrum high reflectance thermal management fabric in this embodiment is the same as that in Embodiment 1, except that the mid-infrared high-emissivity material in the first fiber membrane is selected as polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP).

[0051] Example 8 The preparation method of the full-spectrum high reflectance thermal management fabric in this embodiment is the same as that in Embodiment 1, except that the mid-infrared high-emissivity material in the first fiber membrane is polylactic acid (PLA).

[0052] Example 9 The preparation method of the full-spectrum high reflectance thermal management fabric described in this embodiment is the same as that in Embodiment 1, except that the mid-infrared high-emissivity material in the first fiber membrane is polyvinyl alcohol (PVA).

[0053] Example 10 The preparation method of the full-spectrum high reflectance thermal management fabric described in this embodiment is the same as that in Embodiment 1, except that the mid-infrared high-emissivity material in the first fiber membrane is selected as polyethylene oxide (PEO).

[0054] Example 11 The preparation method of the full-spectrum high reflectance thermal management fabric described in this embodiment is the same as that in Embodiment 1, except that the mid-infrared high-emissivity material in the first fiber membrane is polyoxymethylene (POM).

[0055] Example 12 The preparation method of the full-spectrum high reflectivity thermal management fabric in this embodiment is the same as that in Embodiment 1, except that the infrared high reflectivity material in the first fiber membrane is Ag powder.

[0056] Example 13 The preparation method of the full-spectrum high reflectivity thermal management fabric in this embodiment is the same as that in Embodiment 1, except that the infrared high reflectivity material in the first fiber membrane is Cu powder.

[0057] Comparative Example 1 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the thickness of the first fiber membrane is designed to be 50 μm.

[0058] Comparative Example 2 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the thickness of the first fiber membrane is designed to be 550 μm.

[0059] Comparative Example 3 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the thickness of the infrared high-reflectivity coating is designed to be 3 μm.

[0060] Comparative Example 4 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the thickness of the infrared high-reflectivity coating is designed to be 35 μm.

[0061] Comparative Example 5 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the thickness of the second fiber membrane is designed to be 80 μm.

[0062] Comparative Example 6 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the thickness of the second fiber membrane is designed to be 250 μm.

[0063] Comparative Example 7 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the first fiber membrane is not provided.

[0064] Comparative Example 8 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the second fiber membrane is not provided.

[0065] Comparative Example 9 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that a high-mid-infrared reflective Al layer is sprayed onto the bottom after electrospinning a single-layer PAN fiber film. In this structure, the mid-infrared reflectivity is reduced, and the bottom is highly reflective, which is not conducive to infrared radiation heat transfer from the human body.

[0066] Comparative Example 10 The preparation method of the full-spectrum high-reflectivity thermal management fabric described in this comparative example is the same as that in Example 1, except that the second fiber membrane is replaced with a high-reflectivity particle TiO2 coating.

[0067] Comparative Example 11 The preparation method of the full-spectrum high reflectance thermal management fabric described in this comparative example is the same as that in Example 1, except that the second fiber membrane is replaced with a porous infrared-transmitting film (PE film).

[0068] Experimental Example 1. Optical performance In this experimental example, taking the fabric prepared according to the scheme of Example 1 as an example, the solar reflectance in the range of 0.25-2.5μm was tested using an ultraviolet-visible-near infrared spectrometer; the mid-infrared reflectance in the range of 2.5-20μm was tested using a Fourier transform infrared spectrometer with an integrating sphere to verify its optical performance. The results are shown in Figure 2 (a)-(b).

[0069] In this experimental example, fabrics prepared using the methods of Examples 1-13 and Comparative Examples 1-10 were used to verify other optical properties, and the results are shown in Table 1 below.

[0070] Table 1 Optical performance results It is evident that the fabric prepared by this invention possesses ideal optical properties, exhibiting high reflectivity not only in the solar band to reduce solar radiation heat input, but also in the infrared band to reduce radiation heat input from the surrounding high-temperature environment.

[0071] As can be seen from the schemes of Comparative Examples 1-6, the changes in the parameters of each membrane structure in the fabric will affect the overall optical performance of the fabric. In Comparative Example 7, since the high-emissivity fiber membrane is only removed at the bottom, the impact on the outer optical performance is not significant, and the performance difference is more reflected in the thermal management performance. Similarly, in Comparative Example 9, the impact on the internal high reflectivity is more significant, while the impact on the outer optical performance is relatively small. Therefore, the impact on optical performance is limited.

[0072] 2. Thermal management performance In this experimental example, the fabric prepared according to the scheme of Example 1 is used as an example to test its thermal management performance under extreme thermal environments. The heating power is 140 W / m. 2 The polyimide heating pad was used as simulated skin. Fabric was placed over the simulated skin and vertically in a real outdoor environment, facing a simulated hot building and ground at approximately 60°C, with a relatively small viewing angle (10°) towards the sky. Its thermal management performance was verified by comparing it with ordinary cotton fabric that has a broadband infrared emission. The results are attached. Figure 3 As shown.

[0073] It is evident that the broadband high reflectivity fabric prepared by this invention can reduce the absorption of thermal radiation from the external environment under extreme thermal conditions by utilizing the broadband high reflectivity characteristics of the outer surface, while the high absorption characteristics of the inner side facilitate heat dissipation through conduction and convection, thereby achieving a superior cooling effect.

[0074] In this experimental example, fabrics prepared using the methods of Examples 1-13 and Comparative Examples 1-10 were used to verify their thermal management performance using the aforementioned experimental methods. The test temperatures were reduced by 4℃, 3.85℃, 3.9℃, 3.87℃, 3.91℃, 3.95℃, 4.05℃, 4.03℃, 4℃, 4.06℃, 4.1℃, 4℃, 3.9℃, 1.8℃, 2℃, 3.5℃, 3.6℃, ​​1.9℃, 2.3℃, 1.8℃, 2.4℃, 1.75℃, and 1.6℃, respectively.

[0075] It is evident that the thermal management fabric described in this invention exhibits superior thermal management performance.

[0076] 3. Infrared stealth function In this experimental example, taking the fabric prepared according to Example 1 as an example, infrared thermal images of the broad-spectrum high-reflectivity fabric, ordinary infrared high-emissivity fabric, and infrared high-transmittance fabric were taken with an infrared camera after being covered on a 60°C hot plate for 10 minutes. This verifies its infrared stealth function, and the results are attached. Figure 4 As shown.

[0077] As can be seen, after reaching the thermal equilibrium temperature, both the infrared high-emissivity fabric and the infrared high-transmittance fabric exhibit obvious high-temperature surfaces under the infrared camera. However, the broadband high-reflectivity fabric in Example 1, although having the same temperature, has a significantly lower surface temperature, demonstrating excellent infrared stealth properties.

[0078] 4. Mechanical properties In this experimental example, the fabric prepared according to the scheme of Example 1 was used as an example. The strength of the fabric was tested by a universal testing machine, and its breaking strength was measured to be 8.3 MPa.

[0079] Similarly, based on the aforementioned method, the breaking strengths of the fabrics prepared by Examples 2, 6, 12 and Comparative Examples 1, 4, 11 were 7.6 MPa, 12 MPa, 8.3 MPa, 5.2 MPa, 2.1 MPa, and 1.8 MPa, respectively.

[0080] It is evident that the thermal management fabric described in this invention possesses superior mechanical properties and application performance.

[0081] In summary, the full-spectrum high-reflectivity thermal management fabric of the present invention has a high-infrared emissivity on its inner fiber membrane and a high-infrared reflectivity on its outer fiber membrane while exhibiting high solar reflectivity, thus demonstrating enhanced radiation insulation performance and excellent thermal management effect.

[0082] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A full-spectrum high-reflectivity thermal management fabric, characterized in that, The fabric comprises a composite bottom fiber membrane and a top fiber membrane; wherein, The underlying fiber membrane includes a first fiber membrane formed of a mid-infrared high-emissivity material; The surface fiber membrane includes a second fiber membrane formed of a solar high reflectance and mid-infrared high transmittance material; The bottom fiber membrane is coated with an infrared high reflectivity coating on the side of the top fiber membrane that is close to the bottom fiber membrane. The infrared high reflectivity coating is formed of an infrared high reflectivity material; the mid-infrared high reflectivity material includes at least one of cellulose acetate (CA), thermoplastic polyurethane elastomer (TPU), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polylactic acid (PLA), polyvinyl alcohol (PVA), polyethylene oxide (PEO) or polyoxymethylene (POM). The solar high reflectance and high infrared transmittance material includes at least one of polyacrylonitrile (PAN) or polyamide fiber (PA6); The infrared high reflectivity material includes at least one of aluminum (Al), silver (Ag), copper (Cu), silver nanowires (AgNWs), or two-dimensional transition metal carbon / nitrides (MXene).

2. The full-spectrum high-reflectivity thermal management fabric according to claim 1, characterized in that, In the underlying fiber membrane, the thickness of the first fiber membrane is 100-500 μm.

3. The full-spectrum high-reflectivity thermal management fabric according to claim 1 or 2, characterized in that, In the surface fiber membrane, the molecular weight of the solar high reflectance and high infrared transmittance material is 40,000 to 150,000.

4. The full-spectrum high-reflectivity thermal management fabric according to claim 3, characterized in that, In the surface fiber membrane: The thickness of the second fiber membrane is 100-200 μm; and / or, The fiber diameter of the second fiber membrane is 0.2-2 μm.

5. The full-spectrum high-reflectivity thermal management fabric according to claim 1 or 2, characterized in that, The thickness of the infrared high reflectivity coating is 5-30 μm.

6. A method for preparing a full-spectrum high-reflectivity thermal management fabric as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Take the mid-infrared high-emissivity material and add it to the first spinning solvent for the first mixing to prepare the first spinning solution; use the first electrospinning process to process the first fiber membrane of the required size; (2) Take the infrared high reflectivity material, add the first binder and the first dispersing solvent, and mix them in a second way to prepare a coating liquid; The infrared high-reflectivity coating is formed by spraying it onto the surface of the first fiber membrane; (3) Take the solar high reflectance and high infrared transmittance material and add it to the second spinning solvent for a third mixing to prepare the second spinning solution; use the second electrospinning process to process the second fiber membrane of the required size on the surface of the first coating to obtain the second fiber membrane. or, (1) Take the solar high reflectance and high infrared transmittance material and add it to the second spinning solvent for the third mixing to prepare the second spinning solution; use the second electrospinning process to process the second fiber membrane of the required size; (2) Take the infrared high reflectivity material, add the first binder and the first dispersing solvent, and mix them in a second way to prepare a coating liquid; The infrared high-reflectivity coating is formed by spraying it onto the surface of the second fiber membrane; (3) Take the mid-infrared high-emissivity material and add it to the first spinning solvent for the first mixing to prepare the first spinning solution; A first fiber membrane of the required size is obtained by processing the second coating surface using a first electrospinning process.

7. The method for preparing the full-spectrum high-reflectivity thermal management fabric according to claim 6, characterized in that: In the first spinning solution, the mass ratio of the mid-infrared high-emissivity material is 8-12 wt%; and / or, The first spinning solvent includes N,N-dimethylformamide; and / or, The mixing speed in the first mixing step is 400-600 rpm; and / or, The mixing time for the first mixing step is 6-8 hours; and / or, The receiving distance for the first electrospinning process is 12-18 cm; and / or, The spinning voltage of the first electrospinning process is 18-20kV.

8. The method for preparing the full-spectrum high-reflectivity thermal management fabric according to claim 6 or 7, characterized in that: In the coating liquid, the mass content of the infrared high reflectivity material is 2-15 wt%; and / or, In the coating liquid, the first adhesive comprises acrylic resin; and / or, The first adhesive is based on the infrared high reflectance material having a mass content of 20-50 wt%; and / or, The first dispersing solvent includes tetrachloroethylene; The mixing speed in the second mixing step is 200-600 rpm; and / or, The mixing time for the second mixing step is 4-6 hours; and / or, In the spraying step, the spraying pressure is 15-50 psi, the nozzle diameter is 0.3-0.8 mm, the spraying distance is 5-10 cm, and the sprayed surface density is 250-550 g / m³. 2 .

9. The method for preparing the full-spectrum high-reflectivity thermal management fabric according to any one of claims 6-8, characterized in that: In the second spinning solution, the mass ratio of the solar high reflectance and high infrared transmittance material is 8-12 wt%; and / or, The second spinning solvent includes N,N-dimethylformamide; and / or, The mixing speed in the third mixing step is 400-600 rpm; and / or, The mixing temperature in the third mixing step is 50-60℃; and / or, The mixing time for the third mixing step is 6-8 hours; and / or, The receiving distance for the second electrospinning process is 12-18 cm; and / or, The spinning voltage of the second electrospinning process is 18-20kV.

10. The application of the full-spectrum high reflectivity thermal management fabric according to any one of claims 1-5 or the full-spectrum high reflectivity thermal management fabric prepared by the method according to any one of claims 6-9 in the fields of outdoor clothing, building energy conservation, and automotive interiors.

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