Sandwich structure functional fabric for cold-heat dual-mode all-weather thermal management and application thereof

Abstract

The application discloses a sandwich structure functional fabric for cold-heat dual-mode all-weather thermal management and application thereof, and belongs to the technical field of functional fabric preparation. The sandwich structure functional fabric is prepared by using SEBS as a polymer raw material, using nano metal oxide as a functional filler, mixing and spinning the two to prepare an oriented micro-nano fiber fabric through an orientation spinning technology, orthogonally laminating two layers of the fabric, printing a joule heating circuit between the two layers of the oriented fabric by using liquid metal as a conductive substance, and finally preparing the sandwich structure functional fabric through hot pressing. The sandwich structure functional fabric for cold-heat dual-mode all-weather thermal management prepared by the application has excellent radiation refrigeration capacity and joule heat production capacity, can be applied to personal thermal management under different air temperature conditions, and can provide good wearing comfort.

Description

Technical Field

[0001] This invention belongs to the field of thermal management functional fabrics and their preparation, and more specifically, relates to a sandwich structure functional fabric for all-weather thermal management with both hot and cold modes and its application. Background Technology

[0002] In recent years, thermal management materials have received increasing attention in the fields of wearable devices and functional fabrics. Intelligent thermal management materials, characterized by flexibility, lightweight, and comfortable wearability, have greatly expanded the application of traditional cooling methods in personal thermal management. Daytime radiative cooling is an environmentally friendly cooling technology with zero energy input. It primarily utilizes functional fillers and micro / nano pores within the material to transfer heat generated by the human body to the outside environment. By minimizing solar energy absorption, it achieves a cooling effect where the wearer's perceived temperature is lower than the ambient temperature.

[0003] While reported radiative cooling fabrics possess certain cooling properties, their manufacturing processes are often complex, making it difficult to control fiber diameter and fabric pore size through simple methods to achieve effective scattering of sunlight and high emission in the mid- and far-infrared bands. Furthermore, most reported radiative cooling fabrics only consider daytime cooling needs, neglecting the large diurnal temperature range and the potential for overcooling at night. Therefore, obtaining high-performance radiative cooling fabrics through simple and efficient methods, and combining heating and cooling functions, are key challenges in the fabrication of all-weather thermal management fabrics. Existing patents for radiative cooling fabrics, such as CN114892417A, use acetone and water as pore-forming agents to create a porous coating, requiring strict control of the acetone-to-water ratio to regulate pore size, which is quite complex. Patent CN113561578A does not consider the nighttime overcooling of radiative cooling fabrics, making it difficult to achieve comfortable wear all day. Therefore, designing and manufacturing an all-weather thermal management fabric that combines efficient radiative cooling and heating is of great significance. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a sandwich-structured functional fabric for dual-mode all-weather thermal management and its applications.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] One objective of this invention is to provide a method for preparing a sandwich-structured functional fabric for dual-mode all-weather thermal management, the method comprising:

[0007] (1) Using SEBS masterbatch as raw material, a solution was prepared by chloroform / toluene mixed solvent, and an ionic liquid was added to obtain SEBS solution. Then, nano metal oxide was added and mixed evenly to obtain SEBS / nano metal oxide spinning solution.

[0008] (2) The SEBS / nano metal oxide spinning solution in step (1) is subjected to orientation electrospinning and heat treatment to obtain SEBS / nano metal oxide oriented fiber fabric.

[0009] (3) A serpentine Joule heating circuit is printed on the surface of the SEBS / nano metal oxide oriented fiber fabric in step (2) using gallium indium alloy;

[0010] (4) The SEBS / nano metal oxide oriented fiber fabric obtained in step (2) is stacked with the SEBS / nano metal oxide oriented fiber fabric with Joule heating circuit printed in step (3), and the Joule heating circuit is sandwiched between the two layers of fabric to form a sandwich structure. After hot pressing, a sandwich structure functional fabric for all-weather thermal management in both hot and cold modes is obtained.

[0011] As a preferred embodiment of the present invention, in step (1), the nano-metal oxide is selected from any one or more of TiO2 nanoparticles, Al2O3 nanoparticles, and SiO2 nanoparticles; the particle size of the nano-metal oxide is 200-800 nm.

[0012] As one embodiment of the present invention, in step (1), the mass percentage of SEBS in the SEBS / nano metal oxide spinning solution is 10wt% to 20wt%.

[0013] In one embodiment of the present invention, in step (1), the percentage of ionic liquid in SEBS is 0.3wt% to 0.6wt%.

[0014] As a preferred embodiment of the present invention, in step (1), the ionic liquid is 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide.

[0015] In one embodiment of the present invention, in step (1), the solvent in the spinning solution has a mass ratio of chloroform / toluene of 90:10 to 70:30.

[0016] In one embodiment of the present invention, in step (1), the mass percentage of nano-metal oxide relative to SEBS in the SEBS / nano-metal oxide spinning solution is 5wt% to 40wt%. Further options include 10wt% to 20wt%. Specifically, 10wt% or 15wt% are possible.

[0017] In one embodiment of the present invention, in step (2), the rotation speed of the receiving roller in the orientation electrospinning is 3000-4000 rpm, and the spinning time is 30-90 min.

[0018] As one embodiment of the present invention, in step (2), the heat treatment temperature of the SEBS / nano metal oxide oriented fiber fabric is 60℃~80℃ and the heat treatment time is 10min~40min.

[0019] In one embodiment of the present invention, in step (2), the thickness of the SEBS / nano metal oxide oriented fiber fabric is 150-300 μm.

[0020] In one embodiment of the present invention, in step (3), the printing amount of gallium-indium alloy is 0.1–0.4 g / cm³. 2 .

[0021] In one embodiment of the present invention, in step (4), the two oriented fabrics are orthogonally overlapped at 90°.

[0022] In one embodiment of the present invention, in step (4), the hot pressing temperature is 100℃~120℃ and the hot pressing time is 3min~10min.

[0023] The second objective of this invention is to provide a sandwich structure functional fabric for all-weather thermal management in both hot and cold modes.

[0024] The present invention also provides the application of this fabric in thermal management functional fabrics and comfortable wearable skin-contact devices.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) SEBS thermoplastic elastomer has good weather resistance and anti-aging properties, making it suitable for use in outdoor environments exposed to direct sunlight. Nonwoven fabrics made from SEBS thermoplastic elastomer have the advantages of high elasticity, high breathability, and skin-friendliness, making them suitable as raw materials for wearable thermal management fabrics.

[0027] (2) Polymers can be easily spun into nonwoven fabrics with oriented structures using oriented electrospinning technology. Furthermore, the fiber diameter, orientation degree, and fabric thickness can be easily adjusted by modifying the spinning process (spinning solution composition, spinning voltage, spinning distance, spinning time, receiving roller speed, etc.). In this invention, adding ionic liquid to the spinning solution effectively improves the conductivity of the spinning solution, thereby enhancing the uniformity of fiber diameter.

[0028] (3) TiO2 particles are embedded in SEBS polymer fibers through blending. The low extinction coefficient of TiO2 nanoparticles gives them excellent solar reflectivity. Moreover, when the wavelength is greater than 10 μm, the extinction coefficient of TiO2 particles gradually increases. Therefore, TiO2 can improve the emissivity of radiative cooling materials in the 10-12 μm band.

[0029] (4) By orthogonally stacking two layers of oriented fiber membranes at 90° and hot-pressing them at appropriate temperature and time, it is beneficial to form regular and uniform micropores through thermal fusion between fibers and reduce the average pore size. According to the Mie scattering principle, materials will strongly scatter light with wavelengths close to their pore size. Therefore, orthogonal stacking can achieve efficient reflection of ultraviolet, visible and near-infrared light (0.3-2.5μm).

[0030] (5) Liquid metal (gallium indium alloy) is a low-melting-point alloy with excellent conductivity, good fluidity, good biocompatibility and infinite ductility. Therefore, it is relatively easy to combine with polymer substrates through printing and coating methods to customize and prepare tensile-resistant liquid metal circuits.

[0031] (6) Placing the gallium indium alloy Joule heating circuit between two layers of oriented fiber fabric can prevent liquid from corroding the inner circuit and give the thermal management fabric good environmental adaptability and service life.

[0032] (7) The raw materials of the present invention are inexpensive, the preparation method is simple, and it is easy to carry out mass production.

[0033] The sandwich structure functional fabric for dual-mode all-weather thermal management prepared by this invention has broad application prospects in the fields of flexible wearable devices, radiation cooling fabrics, and personal thermal management materials. Attached Figure Description

[0034] Figure 1 The following are structural schematic diagrams and photographs of a sandwich-structured functional fabric with dual-mode thermal management for both hot and cold weather: (A) Structural schematic diagram, (B) Surface electron microscope image, (C) Cross-sectional electron microscope image, (D) Photograph of gallium-indium alloy heating circuit.

[0035] Figure 2 The diagram shows (A) a radiation cooling mechanism diagram of the sandwich structure functional fabric with dual-mode cooling and all-weather thermal management obtained in Example 1, (B) a real-time temperature diagram of radiation cooling of the sandwich structure functional fabric in the thermal insulation test chamber when the TiO2 content is 0%, 5%, 10%, and 20%, respectively, and (C) the reflectance and emissivity curves of the sandwich structure functional fabric in the 0.3-25μm ultraviolet-visible-near-infrared band when the TiO2 content is 10%.

[0036] Figure 3 The image shows the actual cooling effect of the sandwich structure functional fabric with dual-mode cooling and heating all-weather thermal management obtained in Example 1, compared with four commonly used commercial fabrics: cotton, polyester-cotton blend, polyester, and nylon, under direct sunlight.

[0037] Figure 4The heating performance diagrams of the sandwich structure functional fabric with dual-mode cold and hot all-weather thermal management obtained in Example 1 are as follows: (A) Real-time temperature changes under Joule heating at different voltages, (B) 60 heating cycle tests under 1.8V voltage conditions, and (D) Infrared images of the actual heating application of the thermal management fabric on the back of a human hand. Detailed Implementation

[0038] The present invention will be further illustrated below with specific examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0039] Example 1

[0040] The preparation method of the sandwich structure functional fabric for dual-mode all-weather thermal management in this embodiment is carried out according to the following steps:

[0041] (1) Weigh out 51g of chloroform, 5.7g of toluene, and 50mg of ionic liquid (1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide), mix the three together and stir at room temperature for 10min until they are evenly mixed to obtain a mixed solution.

[0042] (2) Weigh 10g of SEBS masterbatch (Kerten Company, model G1633) and add it to the above mixed solution. Stir at room temperature for 24h until completely dissolved to obtain a SEBS solution with a SEBS concentration of 15wt.%.

[0043] (3) Weigh 1g of TiO2 (100nm particle size) nanoparticles and add them to the above SEBS solution. Stir at room temperature for 24h until TiO2 is evenly dispersed to obtain SEBS / TiO2 spinning solution, wherein the content of TiO2 relative to SEBS is 15wt.%.

[0044] (4) The obtained SEBS / TiO2 composite spinning solution was transferred into a syringe and installed in an electrospinning machine for spinning. The environmental parameters of the electrospinning machine were: temperature 25℃, relative humidity 30RH%. The spinning process parameters were: positive voltage 20kV, negative voltage -5kV, receiving roller speed 3200rpm, receiving distance 15cm, spinning rate 0.2mL / min, and spinning time 60min, to obtain a SEBS / TiO2 oriented fiber fabric with a thickness of 200μm.

[0045] (5) The obtained SEBS / TiO2 composite oriented fiber fabric was placed in an 80℃ forced-air oven for 30 minutes for heat treatment. Heating improved the thermal motion of the molecular chains and eliminated the internal stress of the fiber.

[0046] (6) Using liquid metal (gallium-indium alloy, Ga:In molar ratio = 3:1) as the conductive material, a serpentine Joule heating circuit is printed on the surface of the SEBS / TiO2 composite fiber fabric using a template, wherein the printing amount of gallium-indium alloy is 0.2 g / cm³. 2 .

[0047] (7) The SEBS / TiO2 oriented fiber fabric without liquid metal printing is stacked with the SEBS / TiO2 oriented fabric with Joule heating circuit, so that the liquid metal circuit is sandwiched between the two fabrics to form a sandwich structure, and the orientation direction of the two fabrics is controlled to be orthogonal at a 90° angle. Then, after hot pressing at 110°C for 10 minutes, a sandwich structure functional fabric for cold and hot dual-mode all-weather thermal management is finally obtained.

[0048] Example 2

[0049] The difference between this embodiment and Embodiment 1 is that:

[0050] In step (3), the amount of TiO2 (100nm particle size) nanoparticles added is increased to 3g, that is, the content of TiO2 relative to SEBS is 45wt.%.

[0051] Results Comparison: When the amount of TiO2 added is too large, the nanoparticles agglomerate, which reduces the uniformity of the distribution of TiO2 nanoparticles and reduces the reflectivity of the material to ultraviolet, visible and near-infrared light, thereby reducing the radiative cooling performance. The maximum cooling performance in the heat insulation test chamber is 7℃.

[0052] Example 3

[0053] The difference between this embodiment and Embodiment 1 is that:

[0054] The heat treatment temperature of the blower oven in step (5) is increased to 100°C.

[0055] Results Comparison: Increasing the heat treatment temperature of oriented spun fiber membranes will cause overlapping and fusion between adjacent fibers, which will increase the fiber gap and is not conducive to the formation of micro and nano pores.

[0056] Example 4

[0057] The difference between this embodiment and Embodiment 1 is that:

[0058] In step (6), liquid metal is not printed on the surface of the SEBS / TiO2 composite fiber fabric.

[0059] Results comparison: The prepared functional fabric does not have Joule heating function and cannot achieve all-weather thermal management with both hot and cold modes.

[0060] Example 5

[0061] The difference between this embodiment and Embodiment 1 is that:

[0062] The hot pressing time in step (7) is shortened to 2 minutes.

[0063] Results Comparison: Shortening the hot pressing time will make it difficult for the overlapping fibers to effectively fuse and overlap, and will not be able to form uniform micropores. It will also reduce the interlayer bonding force between the upper and lower fiber fabrics. Ultimately, the functional fabric obtained in this example will peel off when subjected to large stretching.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that:

[0066] In step (3), TiO2 nanoparticles were not added, and the subsequent spinning, heat treatment, and hot pressing processes were the same as in Example 1. Due to the absence of TiO2 nanoparticles, the reflectivity of the prepared fabric to ultraviolet-visible-near-infrared light decreased, and the maximum cooling performance in the heat insulation test chamber was 4℃.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that:

[0069] The heat treatment process for the SEBS / TiO2 composite fiber membrane is omitted in step (5). The subsequent Joule heating circuit printing and hot pressing process are the same as in Example 1. The SEBS / TiO2 composite fiber membrane that has not undergone heat treatment to relieve stress will curl, making it difficult to perform subsequent orthogonal lamination.

[0070] Comparative Example 3

[0071] The difference between this comparative example and Example 1 is that:

[0072] In step (7), the upper and lower SEBS / TiO2 oriented fabrics are not stacked in an orthogonal manner, but arranged in parallel. The subsequent hot pressing process is the same as in Example 1. The parallel arrangement cannot form a uniform micron aperture, and therefore cannot provide efficient reflection of sunlight. Compared with the radiation cooling fabric prepared in Example 1, the cooling performance of the prepared radiation cooling fabric is reduced by about 3.1°C.

[0073] The functional fabrics obtained in Examples 1-5 and Comparative Examples 1-3 were characterized in morphology and tested in performance. The results are as follows: Figures 1-4 As shown.

[0074] Figure 1 This image shows a schematic diagram, electron microscope image, and digital photograph of the sandwich-structured functional fabric with dual-mode (cold and hot) all-weather thermal management prepared in Example 1. Figure 1As can be seen from the electron microscope images of B and C, the sandwich structure prepared by the method of the present invention is clear, and uniform micropores are formed by orthogonal superposition, and the liquid metal circuit is successfully printed on the surface of the functional fabric.

[0075] Figure 2 A is a diagram illustrating the radiation cooling mechanism of the sandwich-structured functional fabric with dual-mode thermal management for all-weather thermal management prepared in Examples 1-5. Figure 2 B shows that when the TiO2 content relative to SEBS is 0, 5 wt.%, 10 wt.%, and 20 wt.%, the sandwich structure functional fabric can achieve a cooling effect of up to 13°C compared to the ambient temperature, indicating its excellent radiative cooling capacity. Figure 2 C shows that when the TiO2 content is 10 wt.%, the sandwich structure functional fabric exhibits extremely high emissivity (up to >96%) in the mid-far infrared band and also has high reflectivity (up to >91%) in the ultraviolet-visible-near infrared band (0.3-2.5 μm).

[0076] Figure 3 The sandwich structure functional fabric with cold and heat dual-mode all-weather thermal management prepared in Example 1 was attached to the skin of a human arm and compared with four commonly used commercial fabrics: cotton, polyester-cotton blend, polyester, and nylon. The infrared image shows that the actual cooling effect is about 3°C ​​lower than that of pure cotton, and it also has a significant advantage over other fabrics.

[0077] Figure 4 The graph shows the heating performance of the sandwich structure functional fabric prepared in Example 1. Figure 4 A represents the Joule heating performance curves under different voltage conditions. Figure 4 B is a graph showing 60 heating cycles at 1.8V, indicating that the liquid metal heating circuit has excellent cycle stability. Figure 4 The actual infrared image of the back of person C's hand shows the rapid heating rate of the functional fabric.

[0078] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for the preparation of sandwich structure functional fabric for cold-heat dual-mode all-weather thermal management, characterized by, Comprising the following steps: (1) SEBS master batch as raw material, chloroform / toluene mixed solvent solution, after adding ionic liquid to obtain SEBS solution, then adding nano metal oxide, mixing uniformly to obtain SEBS / nano metal oxide spinning solution; nano metal oxide is TiO2 nanoparticles; the mass percentage of nano metal oxide in SEBS / nano metal oxide spinning solution is 5 wt%-40 wt% relative to SEBS; (2) SEBS / nano metal oxide oriented fiber fabric is obtained by orienting electrospinning, heat treatment of SEBS / nano metal oxide spinning solution in step (1); the heat treatment temperature is 60 °C-80 °C; the heat treatment time is 10 min-40 min; (3) Using gallium-indium alloy to print a serpentine Joule heating circuit on the surface of SEBS / nano metal oxide oriented fiber fabric in step (2); (4) The SEBS / nano metal oxide oriented fiber fabric obtained in step (2) is overlapped with the SEBS / nano metal oxide oriented fiber fabric printed with Joule heating circuit obtained in step (3), and the Joule heating circuit is sandwiched between the two layers of fabric to form a sandwich structure, and after hot pressing, a sandwich structure functional fabric for cold and hot dual mode all-weather thermal management is prepared; the two layers of oriented fabric are overlapped at 90 °, and the hot pressing temperature is 100 °C-120 °C, and the hot pressing time is 3 min-10 min.

2. The method of claim 1, wherein, In step (1), the mass percentage of SEBS in SEBS / nano metal oxide spinning solution is 10 wt%-20 wt%; the percentage of ionic liquid in SEBS is 0.3 wt%-0.6 wt%.

3. The method of claim 1, wherein, In step (1), the mass ratio of chloroform / toluene in the solvent of the spinning solution is 90:10-70:

30.

4. The method of claim 1, wherein, In step (2), the rotating speed of the receiving roller in the orienting electrospinning is 3000-4000 rpm, and the spinning time is 30-90 min.

5. The method of claim 1, wherein, In step (2), the thickness of SEBS / nano metal oxide oriented fiber fabric is 150-300 μm.

6. The method of claim 1, wherein, In step (3), the printing amount of the gallium-indium alloy is 0.1 to 0.4 g / cm 2 .

7. A sandwich structure functional fabric for cold and hot dual mode all-weather thermal management prepared by the method of any one of claims 1-6.

8. The use of the sandwich structure functional fabric for cold and hot dual mode all-weather thermal management of claim 7 in a comfortable wearable smart thermal management fabric.

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