Personal thermal management fabric with temperature visualization function and preparation method thereof

Abstract

A preparation method for a personal thermal management fabric with a temperature visualization function comprises the following steps: wet spinning polyurethane doped with Ag nanoparticles to obtain silver-containing conductive fibers, annealing on a 160°C hot plate for 5-10 minutes, and then treating with oxygen plasma for 30 seconds; dispersing 0.1-0.3wt% of negatively charged thermochromic powder, 0.3-0.5wt% of aqueous polyurethane, and 0.05wt% of sodium lauryl sulfate in deionized water to prepare an electrophoretic solution; electrophoretically depositing the treated silver-containing conductive fibers with the electrophoretic solution to obtain thermochromic conductive fibers; and weaving the thermochromic conductive fibers through a textile weaving process to obtain a personal thermal management fabric with a temperature visualization function. The fabric of the present invention achieves a dynamic thermal management effect, that is, in a hot environment, it can achieve a cooling effect 2.5K lower than that of ordinary white fabrics. In a cold environment, by combining Joule heat and photothermal effects, it can achieve more energy savings while providing the same heating effect.

Description

Technical Field

[0001] The present invention relates to the field of temperature-sensitive color-changing materials and textile technology, and in particular to a personal thermal management fabric with temperature visualization function and a preparation method thereof. Background Art

[0002] Maintaining thermal homeostasis is crucial for thermal comfort and thermal health. Current thermal management technologies, including air conditioning and ventilation, consume significant energy and are not suitable for outdoor environments. More importantly, they indiscriminately fail to meet the unique thermal management needs of each individual. Consequently, the concept of personal thermal management has emerged in recent years, with the core concept being personal thermal management fabrics. These fabrics regulate the body's thermal radiation rather than regulating ambient temperature to provide thermal comfort. Therefore, personal thermal management technology offers a new strategy that is both energy-efficient and highly efficient.

[0003] Currently, personal thermal management fabrics are primarily categorized as heating and cooling fabrics. Heating fabrics must possess excellent solar absorptivity and infrared reflectivity. High solar absorptivity maximizes heat accumulation, while high infrared reflectivity minimizes radiative heat loss from the human body. In contrast, cooling fabrics require extremely high solar reflectivity to prevent temperature rise caused by the photothermal effect. Spectral design options for the infrared region include high transmittance and high emissivity. High-transmittance fabrics minimize thermal radiation blockage, while high-emissivity fabrics use themselves as a heat source, indirectly enhancing heat dissipation from the human body. Experiments have shown that both types of cooling fabrics can achieve effective cooling. However, fabrics designed solely for heating or cooling struggle to cope with changing climate conditions. Furthermore, personal thermal management fabrics that rely on radiation regulation have limited temperature control capabilities. A combination of multiple thermal regulation methods could broaden the fabric's applicability. Summary of the Invention

[0004] Based on this, the present invention provides a thermochromic conductive fiber to solve the technical problem that the existing personal thermal management fabrics rely on a single heating or cooling fabric and are difficult to cope with changing climate conditions and have limited temperature control capabilities.

[0005] To achieve the above object, the present invention provides a thermochromic conductive fiber, which comprises the following steps:

[0006] 1) Wet spinning polyurethane doped with Ag nanoparticles to obtain silver-containing conductive fibers;

[0007] 2) annealing the silver-containing conductive fibers on a hot plate at 160° C. for 5-10 minutes, and then subjecting the fibers to oxygen plasma treatment for 25-30 seconds;

[0008] 3) dispersing 0.1-0.3 wt% of negatively charged thermochromic powder, 0.3-0.5 wt% of aqueous polyurethane, and 0.05 wt% of sodium lauryl sulfate in deionized water to prepare an electrophoretic solution; subjecting the silver-containing conductive fibers treated in step 2) to electrophoretic deposition using the electrophoretic solution, and drying the solution to obtain thermochromic conductive fibers;

[0009] 4) Thermochromic conductive fibers are subjected to a textile weaving process to obtain personal thermal management fabrics with temperature visualization function.

[0010] As a further preferred technical solution of the present invention, step 1) specifically includes:

[0011] Polyurethane particles were dissolved in N,N-dimethylformamide solvent to obtain a PU solution with a concentration of 0.2 g / mL; Ag nanoparticles with a volume fraction of 40% were dispersed in the PU solution by probe ultrasound, and bubbles were removed by negative pressure to obtain an Ag / PU precursor;

[0012] The Ag / PU precursor was squeezed into deionized water through a syringe at a speed of 15-20 μL / min, and the obtained fibers were pulled and stretched and continuously collected with a reel; the obtained fibers were then immersed in an ethanol solution and dried to obtain silver-containing conductive fibers with a diameter of 150 μm.

[0013] As a further preferred technical solution of the present invention, in step 3), during the electrophoretic deposition operation, a group of copper sheets are connected to the negative electrode of the power supply, and the silver-containing conductive fibers are connected to the positive electrode of the power supply and immersed in the electrophoretic solution. By applying a voltage between the negative electrode and the positive electrode of the power supply, the thermochromic powder material and the water-based polyurethane are deposited on the surface of the conductive fibers.

[0014] As a further preferred technical solution of the present invention, the textile weaving process in step 4) uses ordinary commercial fabrics and thermochromic conductive fibers, wherein the thermochromic conductive fibers are arranged in parallel in the vertical direction, and the ordinary commercial fabrics are alternately woven into each thermochromic conductive fiber in the horizontal direction.

[0015] As a further preferred technical solution of the present invention, in the personal thermal management fabric with temperature visualization function, the number density of the thermochromic conductive fibers is 18 fibers / cm.

[0016] As a further preferred technical solution of the present invention, the thermochromic temperature of the thermochromic powder is 25 to 30 degrees.

[0017] According to another aspect of the present invention, a personal thermal management fabric with temperature visualization function is also provided. It achieves low-energy dynamic thermal management by combining two different methods: Joule heating and solar spectrum regulation. Specifically, in a hot environment, the fabric can spontaneously change from color (colored state) to white to reduce the photothermal effect. At the same time, the ultra-high infrared emissivity (95%) helps dissipate heat. The combination of the two enables the thermal management fabric to achieve a cooling effect that is 2.5K lower than that of ordinary white fabric, while commercial fabrics of the same color are 7.5-16K higher than ordinary white fabrics. In a cold environment, the fabric can automatically change to color to increase the photothermal effect. At the same time, the conductive core layer can provide efficient Joule heat. The combination of the two can provide thermal comfort conditions that adapt to the human body. In addition, while ensuring the same heating temperature, the photothermal effect can also greatly reduce the energy consumption of Joule heat. Compared with fabrics that rely solely on Joule heat for heating, this thermal management fabric can achieve 625W / m 2 In addition, this thermochromic fabric also provides an instant and sensitive temperature visualization function, which helps to judge the temperature distribution of the human body and provide people with a visual heat warning.

[0018] The personal thermal management fabric with temperature visualization function and the preparation method thereof of the present invention can achieve the following beneficial effects by adopting the above technical solutions:

[0019] 1) The preparation method proposed by the present invention is simple and easy to prepare for industrial production;

[0020] 2) The present invention provides a personal thermal management fabric that achieves a dynamic thermal management effect, that is, in a hot environment, it can achieve a cooling effect 2.5K lower than that of ordinary white fabrics. In a cold environment, by combining Joule heating and photothermal effects, it can achieve more energy savings (625W / m 2 );

[0021] 3) The present invention provides a personal thermal management fabric that achieves the effect of temperature visualization. The thermochromic conductive fabric can visualize 1064nm laser light. When the laser is irradiated on the surface of the fabric, the shape of the laser spot and the temperature distribution can be clearly seen, which plays a role in thermal warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 Schematic diagram and optical photograph of the preparation of thermochromic conductive fibers in Example 1;

[0024] Figure 2: This is an electron microscope image of the silver-containing conductive fiber and thermochromic fiber prepared in Example 1;

[0025] Figure 3 Spectra of the red thermochromic conductive fabric prepared in Example 2, commercial red fabric, and commercial white fabric;

[0026] Figure 4 This is a visualization of the thermal management effect and temperature of the thermochromic conductive fabric prepared in Example 3.

[0027] Figure 5 This is the thermal visualization effect of the three-color thermochromic conductive fabric prepared in Example 4.

[0028] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0029] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0030] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents; the experimental methods described, unless otherwise specified, are conventional methods.

[0031] Example 1

[0032] This embodiment provides a method for preparing a personal thermal management fabric with temperature visualization function. The preparation process is as follows: Figure 1 The specific preparation method is as follows:

[0033] Step 1) First, polyurethane (PU) particles are dissolved in DMF at a concentration of 0.2g / mL. Then, Ag nanoparticles with a volume fraction of 40% are dispersed in the PU solution through probe ultrasound. After removing bubbles by negative pressure, the Ag / PU precursor is used. The Ag / PU precursor is transferred to a syringe and squeezed into deionized water using a syringe pump (20μL / min) to remove the solvent. The Ag / PU precursor is then stretched and the resulting fibers are continuously collected using a reel. Finally, the resulting fibers are immersed in an ethanol solution (95%) to completely remove the solvent and air-dried to obtain silver-containing conductive fibers (Ag-PU fibers) with a diameter of 150μm.

[0034] Step 2) Based on the Ag-PU fiber, thermochromic conductive fiber is obtained by electrophoretic deposition method. First, the Ag-PU fiber obtained above is annealed on a 160°C hot plate for 10 minutes and then treated with oxygen plasma for 30 seconds; then 1%wt of thermochromic powder, 0.3% water-based polyurethane, and 0.05wt% of sodium lauryl sulfate purchased from Shenzhen Huancai Bianse Technology Co., Ltd. are dispersed in deionized water, and the mixture is used as an electrophoretic fluid; a group of copper sheets are connected to the negative pole of the power supply, and the Ag-PU fiber treated with oxygen plasma is connected to the positive pole of the power supply and immersed in the electrophoretic fluid. When a certain voltage is applied, the thermochromic material and water-based polyurethane in the electrophoretic fluid are quickly deposited on the surface of the conductive fiber, and dried in the air to obtain thermochromic conductive fiber.

[0035] Step 3) A personal thermal management fabric with temperature visualization is woven from thermochromic conductive fibers and a small amount of common commercial fabric. Specifically, the thermochromic conductive fibers are arranged vertically in parallel, and the common commercial fabric is alternately woven horizontally into each thermochromic conductive fiber. The resulting personal thermal management fabric has a number density of 18 thermochromic conductive fibers per cm.

[0036] Figure 2 The cross-sectional morphology of the Ag-PU fiber prepared in Example 1 before and after annealing and the cross-sectional morphology of the thermochromic conductive fiber are shown. It can be seen that before annealing, the Ag-PU fiber has a large number of pore structures. After annealing, the pores in the Ag-PU fiber are significantly reduced, so the conductivity is greatly improved. On this basis, the thermochromic conductive fiber prepared by electrophoretic deposition has a core-shell structure, wherein the core layer is Ag-PU fiber and the shell layer is a mixture of thermochromic material and waterborne polyurethane (WPU). The interface morphology shows that the WPU in the shell layer penetrates into the core layer Ag-PU fiber, which not only greatly enhances the mechanical properties of the fiber, but also enables the thermochromic material to better adhere to the surface of the Ag-PU fiber.

[0037] It should be noted here that the thermochromic powder of the present invention can be purchased from Shenzhen Huancai Bianse Technology Co., Ltd. The thermochromic powder is also called reversible thermochromic pigment, which is a powder particle (microcapsule) that repeatedly changes color as the temperature rises or falls. The particles are spherical and have an average diameter of 2 to 7 microns. The thermochromic powder can be prepared from an electron transfer type organic compound system. At a specific temperature (thermochromic temperature), the molecular structure of the organic matter changes due to electron transfer, thereby achieving color transformation, thereby achieving color change from "colored-colorless" and "colorless-colored" states. Of course, in actual use, it is not limited to the thermochromic powder sold by Shenzhen Huancai Bianse Technology Co., Ltd., it can also use other thermochromic powders in the prior art that have the above-mentioned functional characteristics.

[0038] Therefore, according to different actual needs, the present invention can be doped with thermochromic powder that changes a single color or thermochromic powder that changes multiple colors during the preparation of thermochromic conductive fibers. The thermochromic powder that changes multiple colors can present different colors depending on the temperature.

[0039] Example 2

[0040] Red thermochromic conductive fabric was prepared using the same method as in Example 1. While maintaining all other process conditions, the thermochromic powder, which changes color to red at different temperatures, was used as the raw material for the thermochromic conductive fiber. The thermochromic conductive fiber was thermochromic, meaning it was colored at low temperatures and turned colorless when the temperature reached a set value. The set temperature (thermochromic temperature) was preferably 25-30°C.

[0041] The red thermochromic conductive fabric of this embodiment was compared with ordinary fabrics, and the test results are as follows: Figure 3 . Figure 3 The red thermochromic conductive fabric prepared in Example 1, as well as the absorptivity / emissivity spectra of commercial red fabric and commercial white fabric are shown. In a hot environment, the thermochromic conductive fabric spontaneously turns white, greatly reducing the absorption in the 0.4-2μm range to reduce the photothermal effect, while the corresponding commercial red fabric does not change and still maintains a high absorption. At the same time, the red thermochromic conductive fabric has a higher emissivity in the mid-infrared part (8-13μm) than the commercial red fabric, making the spontaneous heat dissipation higher than that of the commercial red fabric. The combination of the two makes the red thermochromic conductive fabric have an excellent cooling effect in a hot environment. On the contrary, in cold conditions, the thermochromic conductive fabric spontaneously turns red to enhance the photothermal effect, and the absorptivity is almost equal to that of the commercial red fabric, with an excellent heating effect.

[0042] Example 3

[0043] Four different colors of thermochromic conductive fabrics were prepared using the same method as in Example 1. While maintaining all other process conditions, only four different temperature-shifting color thermochromic powders were used as the raw materials for the thermochromic conductive fibers. These were thermochromic, meaning they were colored at low temperatures and turned colorless when the temperature reached a set value. The set temperature (thermochromic temperature) was preferably between 25 and 35 degrees Celsius.

[0044] The red thermochromic conductive fabric of this embodiment was compared with ordinary fabrics, and the test results are as follows: Figure 4 . Figure 4The thermal management performance of four different colors of thermochromic conductive fabrics was demonstrated. In a hot environment, the fabric can spontaneously change from color to white to reduce the photothermal effect. At the same time, the ultra-high infrared emissivity (95%) helps dissipate heat. The combination of the two enables the thermal management fabric to achieve a cooling effect 2.5K lower than ordinary white fabrics, while commercial fabrics of the same color are 7.5-16K higher than ordinary white fabrics. In a low-temperature environment, the fabric can spontaneously change from white to color to increase the photothermal effect. At this time, the heating effect of the thermochromic conductive fabric is slightly lower than that of ordinary commercial fabrics. However, the Ag-PU fiber in the core layer can provide efficient Joule heating function through an external power supply to make up for this part. The combination of the two can provide thermal comfort conditions that adapt to the human body. In addition, while ensuring the same heating temperature, the photothermal effect can also greatly reduce the energy consumption of Joule heat. Compared with fabrics that rely solely on Joule heat for heating, this thermal management fabric can achieve 625W / m 2 energy-saving effect.

[0045] Example 4

[0046] Four thermochromic conductive fabrics of different colors were prepared according to the preparation method of Example 1. While keeping the other process conditions unchanged, the thermochromic powder of the thermochromic type was replaced with a thermochromic powder with three color changes as the raw material of the thermochromic conductive fiber, i.e., purple below 20 degrees, red between 20 and 28 degrees, and yellow above 28 degrees.

[0047] Figure 5 Demonstrating the thermal visualization capabilities of thermochromic conductive fabrics. Fabrics made from color-changing thermochromic materials are highly sensitive to temperature. When an invisible 1064nm laser is irradiated on the fabric surface, a concentric circular pattern of light spots gradually appears. The corresponding infrared thermal image also reveals the heat distribution within these concentric circular patterns. This thermal visualization capability can provide thermal monitoring and early warning for the human body, preventing thermal damage in challenging environments (such as high-energy infrared radiation).

[0048] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to the embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a personal thermal management fabric with temperature visualization function, characterized in that: The following steps are involved: 1) using a wet spinning process on polyurethane doped with Ag nanoparticles to obtain silver-containing conductive fibers; 2) annealing the silver-containing conductive fibers on a hot plate at 160° C. for 5-10 minutes, and then subjecting the fibers to oxygen plasma treatment for 25-30 seconds; 3) dispersing 0.1-0.3 wt% of negatively charged thermochromic powder, 0.3-0.5 wt% of aqueous polyurethane, and 0.05 wt% of sodium lauryl sulfate in deionized water to prepare an electrophoretic solution; subjecting the silver-containing conductive fibers treated in step 2) to electrophoretic deposition using the electrophoretic solution, and drying the solution to obtain thermochromic conductive fibers; 4) Thermochromic conductive fibers are subjected to a textile weaving process to obtain personal thermal management fabrics with temperature visualization function.

2. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, characterized in that: Step 1) specifically includes: Polyurethane particles were dissolved in N,N-dimethylformamide solvent to obtain a PU solution with a concentration of 0.2 g / mL; Ag nanoparticles with a volume fraction of 40% were dispersed in the PU solution by probe ultrasound, and bubbles were removed by negative pressure to obtain an Ag / PU precursor; The Ag / PU precursor was squeezed into deionized water through a syringe at a speed of 10-20 μL / min, and the resulting fibers were continuously collected using a reel; the resulting fibers were then immersed in an ethanol solution and dried to obtain silver-containing conductive fibers with a diameter of 150 μm.

3. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, characterized in that: In step 3), during the electrophoretic deposition operation, a group of copper sheets are connected to the negative electrode of the power supply, and the silver-containing conductive fibers are connected to the positive electrode of the power supply and immersed in the electrophoretic solution. By applying a voltage between the negative electrode of the power supply and the positive electrode of the power supply, the thermochromic powder material and the water-based polyurethane are deposited on the surface of the conductive fibers.

4. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, characterized in that: The textile weaving process in step 4) uses common commercial fabrics and thermochromic conductive fibers, wherein the thermochromic conductive fibers are arranged in parallel in the vertical direction, and the common commercial fabrics are alternately woven into each of the thermochromic conductive fibers in the horizontal direction.

5. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, characterized in that: In the personal thermal management fabric with temperature visualization function, the number density of the thermochromic conductive fibers is 18 fibers / cm.

6. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, characterized in that: The thermochromic temperature of the thermochromic powder is 25 to 30 degrees.

7. A personal thermal management fabric with temperature visualization function, characterized in that: The method is prepared by any one of claims 1 to 6.

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