A composite fiber with infrared stealth function and its preparation method

Abstract

This invention relates to a composite fiber with infrared stealth function and its preparation method, belonging to the field of functional fiber technology. The composite fiber with infrared stealth function of this invention comprises a core layer, a hollow fiber layer, a nanofiber layer, and a pigment coating layer arranged sequentially; the core layer is liquid metal; the hollow fiber layer is polyurethane / vanadium dioxide hollow composite fiber; the nanofiber layer is silk fibroin / titanium dioxide nanocomposite fiber; and the pigment coating layer is a metallic coating. The composite fiber with infrared stealth function of this invention exhibits excellent infrared stealth performance, mainly by reducing its own infrared emissivity through vanadium dioxide and metallic coating, while simultaneously utilizing liquid metal and titanium dioxide to lower the product temperature and reduce radiation. In addition, the use of polyurethane provides the fiber with good flexibility, allowing it to better conform to human movement.

Description

Technical Field

[0001] This invention belongs to the field of functional fiber technology, and particularly relates to a composite fiber with infrared stealth function and its preparation method. Background Technology

[0002] With the rapid development of technology, military detection technologies are constantly being updated and iterated, making precision-guided weapons extremely dangerous to personnel and equipment. Therefore, the infrared stealth capabilities of military personnel and weaponry are receiving increasing attention worldwide. At the same time, considering the comfort of human clothing, the breathability and flexibility of infrared stealth materials are also becoming increasingly important.

[0003] Chinese invention patent CN 109233410A discloses an infrared stealth coating and its preparation method, as well as an infrared stealth fabric and its preparation method. The infrared stealth coating includes a composite frequency material and an adhesive. Chinese invention patent CN115851226A discloses a silicon carbide aerogel-based infrared radar dual stealth material and its preparation method, made of a phase change material, silicon carbide, and a microwave absorbing material. The microwave absorbing material is coated on the surface of silicon carbide nanowires, and the phase change material fills the pores of the silicon carbide nanowire aerogel. Chinese invention patent CN 113248962A discloses an infrared stealth coating and its preparation method, the components of which consist of a solvent, adhesive, filler, anti-settling agent, and additives.

[0004] The aforementioned infrared stealth material is prepared by coating the fabric surface with infrared stealth coating. Although it has good infrared stealth performance, it has poor breathability and flexibility, making it unsuitable for long-term human wear. In addition, its preparation method has poor continuity and low production efficiency. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a composite fiber with infrared stealth capabilities and its preparation method. The fiber uses a metal core, polyurethane / vanadium dioxide hollow composite fibers as hollow fiber layers, silk fibroin / titanium dioxide nanocomposite fibers as nanofiber layers, and a metal coating as a pigment coating layer. Liquid metal is filled into the interior of the polyurethane / vanadium dioxide hollow composite fibers using microfluidic wet spinning technology. Silk fibroin / titanium dioxide nanocomposite fibers are then coated onto the surface of the hollow fiber layers using electrospinning technology. Finally, the metal coating is sprayed onto the surface of the nanofiber layers to produce a composite fiber with infrared stealth capabilities. The composite fiber exhibits good infrared performance, high flexibility, and high production efficiency.

[0006] The first objective of this invention is to provide a composite fiber with infrared stealth capabilities, comprising a core layer, a hollow fiber layer, a nanofiber layer, and a pigment coating layer arranged sequentially; the core layer is liquid metal; the hollow fiber layer is polyurethane / vanadium dioxide hollow composite fiber; the nanofiber layer is silk fibroin / titanium dioxide nanocomposite fiber; and the pigment coating layer is a metal coating.

[0007] In one embodiment of the present invention, the liquid metal is a gallium indium tin alloy.

[0008] In one embodiment of the present invention, the metal coating is obtained by mixing copper powder, graphene, antimony-doped tin oxide, epoxy resin and phenolic resin in a mass ratio of 5-7:1-2:0.5-1:0.5-2:0.5-1.5.

[0009] In one embodiment of the present invention, the radius of the core layer is 0.1 mm-2 mm; the thickness of the hollow fiber layer is 1 mm-3 mm; the thickness of the nanofiber layer is 1 mm-3 mm; and the thickness of the pigment coating layer is 30 μm-100 μm.

[0010] Further, the radius of the core layer is 0.1mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, or 2mm; or any radius between any two values.

[0011] Furthermore, the thickness of the hollow fiber layer is 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, or 3 mm; or any thickness between any two values.

[0012] Furthermore, the thickness of the nanofiber layer is 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, or 3 mm; or any thickness between any two values.

[0013] Further, the thickness of the pigment coating layer is 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, 58μm, 59μm, 60μm, 61μm, 62μm, 63μm, 64μm, 65μm, etc. μm, 66μm, 67μm, 68μm, 69μm, 70μm, 71μm, 72μm, 73μm, 74μm, 75μm, 76μm, 77μm, 78μm, 79μm, 80μm, 81μm, 82μm, 83μm, 84μm , 85μm, 86μm, 87μm, 88μm, 89μm, 90μm, 91μm, 92μm, 93μm, 94μm, 95μm, 96μm, 97μm, 98μm, 99μm, 100μm; or any thickness between any two values.

[0014] The second objective of this invention is to provide a method for preparing the composite fiber with infrared stealth function, comprising the following steps:

[0015] S1. Polyurethane / vanadium dioxide spinning solution is used to form polyurethane / vanadium dioxide hollow composite fibers through microfluidic wet spinning technology to form a hollow fiber layer; and liquid metal is injected into the hollow fiber layer using a coaxial needle to form a core layer.

[0016] S2. The silk fibroin / titanium dioxide spinning solution is made into silk fibroin / titanium dioxide nanocomposite fibers by electrospinning technology, and coated on the surface of the hollow fiber layer treated by S1 to form a nanofiber layer.

[0017] S3. The fibers treated in S2 are heated, and a metal coating is sprayed onto the surface of the nanofiber layer to form a pigment coating layer, thereby obtaining the composite fiber with infrared stealth function.

[0018] In one embodiment of the present invention, in S1, the polyurethane / vanadium dioxide spinning solution includes polyurethane, vanadium dioxide and solvent A, wherein the mass fraction of polyurethane in the polyurethane / vanadium dioxide spinning solution is 10%-30% and the mass fraction of vanadium dioxide is 30%-60%; the solvent A is selected from N,N-dimethylformamide (DMF) and / or dichloromethane.

[0019] In one embodiment of the present invention, in S1, the extrusion speed of the liquid metal is 3 mL / h-6 mL / h, and the extrusion speed of the polyurethane / vanadium dioxide spinning solution is 7 mL / h-10 mL / h.

[0020] Further, in S1, the extrusion rate of the liquid metal is 3 mL / h, 3.1 mL / h, 3.2 mL / h, 3.3 mL / h, 3.4 mL / h, 3.5 mL / h, 3.6 mL / h, 3.7 mL / h, 3.8 mL / h, 3.9 mL / h, 4 mL / h, 4.1 mL / h, 4.2 mL / h, 4.3 mL / h, 4.4 mL / h, 4.5 mL / h, 4.6 mL / h, 4.7 mL / h, 4.8 mL / h, 4.9 mL / h, 5 mL / h, 5.1 mL / h, 5.2 mL / h, 5.3 mL / h, 5.4 mL / h, 5.5 mL / h, 5.6 mL / h, 5.7 mL / h, 5.8 mL / h, 5.9 mL / h, or 6 mL / h; or any extrusion rate between any two values.

[0021] Further, in S1, the extrusion rate of the polyurethane / vanadium dioxide spinning solution is 7 mL / h, 7.1 mL / h, 7.2 mL / h, 7.3 mL / h, 7.4 mL / h, 7.5 mL / h, 7.6 mL / h, 7.7 mL / h, 7.8 mL / h, 7.9 mL / h, 8 mL / h, 8.1 mL / h, 8.2 mL / h, 8.3 mL / h, 8.4 mL / h, 8.5 mL / h, 8.6 mL / h, 8.7 mL / h, 8.8 mL / h, 8.9 mL / h, 9 mL / h, 9.1 mL / h, 9.2 mL / h, 9.3 mL / h, 9.4 mL / h, 9.5 mL / h, 9.6 mL / h, 9.7 mL / h, 9.8 mL / h, 9.9 mL / h, or 10 mL / h; or any extrusion rate between any two values.

[0022] In one embodiment of the present invention, in S2, the silk fibroin / titanium dioxide spinning solution includes silk fibroin, titanium dioxide and solvent B, wherein the mass fraction of silk fibroin in the silk fibroin / titanium dioxide spinning solution is 1%-10% and the mass fraction of titanium dioxide is 10%-40%; the solvent B is selected from hexafluoroisopropanol (HFIP) and / or formic acid.

[0023] In one embodiment of the present invention, in S2, the conditions for electrospinning are: injection pump speed of 0.5 mL / h-2.5 mL / h, voltage of 10 kV-15 kV, and receiving distance of 10 cm-20 cm.

[0024] Further, in S2, the injection pump speed is 0.5 mL / h, 0.6 mL / h, 0.7 mL / h, 0.8 mL / h, 0.9 mL / h, 1.0 mL / h, 1.1 mL / h, 1.2 mL / h, 1.3 mL / h, 1.4 mL / h, 1.5 mL / h, 1.6 mL / h, 1.7 mL / h, 1.8 mL / h, 1.9 mL / h, 2.0 mL / h, 2.1 mL / h, 2.2 mL / h, 2.3 mL / h, 2.4 mL / h, 2.5 mL / h; or any speed between any two values.

[0025] Furthermore, in S2, the voltage is 10kV, 11kV, 12kV, 13kV, 14kV, 15kV; or any voltage between any two values.

[0026] Further, in S2, the receiving distance is 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, 20cm; or any distance between any two values.

[0027] In one embodiment of the present invention, in S2, the heating temperature is 50°C-80°C and the heating time is 5s-30s.

[0028] Further, in S2, the heating temperature is 50℃, 51℃, 52℃, 55℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, 61℃, 62℃, 63℃, 66℃, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 77℃, 75℃, 77℃, 77℃, 78℃, 79℃, 80℃; or any temperature between any two values.

[0029] Further, in S2, the time is 5s, 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s, 14s, 15s, 16s, 17s, 18s, 19s, 20s, 21s, 22s, 23s, 24s, 25s, 26s, 27s, 28s, 29s, 30s; or any time between any two values.

[0030] The technical solution of the present invention has the following advantages compared with the prior art:

[0031] (1) The composite fiber with infrared stealth function described in this invention has a hollow fiber layer of polyurethane / vanadium dioxide hollow composite fiber. Therefore, the fiber not only has excellent infrared stealth performance, but also has good flexibility. At the same time, the use of liquid metal as the core layer and silk fibroin / titanium dioxide nanocomposite fiber as the nanofiber layer can give the fiber good radiative cooling performance, reduce the temperature of the fiber itself, and thus enhance the infrared stealth performance. Moreover, the use of metal coating sprayed on the fiber surface helps to reduce the infrared emissivity of the fiber, which can further enhance its infrared stealth performance. Furthermore, the preparation method of infrared stealth fiber has good production continuity and high production efficiency.

[0032] (2) The composite fiber with infrared stealth function described in this invention has excellent infrared stealth performance, mainly by reducing its own infrared emissivity through vanadium dioxide and metallic coating, and by using liquid metal and titanium dioxide to reduce the product temperature and radiation. In addition, the use of polyurethane can provide the fiber with better flexibility, allowing it to better conform to human movement.

[0033] (3) The preparation method described in this invention uses a combination of microfluidics, electrospinning and spraying technologies to prepare the product, which can be carried out continuously and with high efficiency. At the same time, the preparation method can combine multiple materials on the product, so that it has good infrared stealth performance and good flexibility, which can meet the daily behavior of the human body. Attached Figure Description

[0034] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0035] Figure 1 This is a schematic diagram of the preparation system for the composite fiber with infrared stealth function of the present invention;

[0036] Figure 2 This is a schematic diagram of the cross-sectional structure of the composite fiber with infrared stealth function of the present invention;

[0037] Explanation of reference numerals in the attached figures: 1-Polyurethane / vanadium dioxide spinning solution, 2-Coaxial needle, 3-Liquid metal, 4-Coagulation bath, 5-Silk fibroin / titanium dioxide nanocomposite fiber, 6-Heating channel, 7-Metallic coating, 8-Sprayer, 9-Composite fiber with infrared stealth function, 91-Core layer, 92-Hollow fiber layer, 93-Nanofiber layer, 94-Pigment coating layer. Detailed Implementation

[0038] Specific embodiments are provided to further illustrate the present invention, enabling those skilled in the art to better understand and implement it. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. It should be understood that the specific embodiments are only used to explain the present invention, and are not intended to limit the present invention.

[0039] In this invention, unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0040] In this invention, unless otherwise stated, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] In this invention, unless otherwise specified, the experimental methods used in the embodiments of this invention are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0042] In this invention, unless otherwise stated, the gallium indium tin alloy used in the embodiments was purchased from UTP Technology Suzhou Co., Ltd., model number M02244.

[0043] In this invention, unless otherwise stated, the polyurethane used in the embodiments was purchased from Beijing Innocare Technology Co., Ltd., model number GF51991757-1EA.

[0044] In this invention, unless otherwise stated, the vanadium dioxide used in the embodiments was purchased from Suzhou Ruijing Biotechnology Co., Ltd., model V70019.

[0045] In this invention, unless otherwise stated, the silk fibroin used in the embodiments was purchased from UTP Technology Suzhou Co., Ltd., model number W293432.

[0046] In this invention, unless otherwise stated, the titanium dioxide used in the embodiments was purchased from Suzhou Ketong Biomedical Technology Co., Ltd., model number C21358.A1.

[0047] In this invention, unless otherwise stated, the commercially available fabric with infrared stealth function used in the embodiments was purchased from Suzhou Haokai Textile Co., Ltd., model HK1006.

[0048] In this invention, unless otherwise stated, the metal coating used in the embodiments is obtained by mixing copper powder, graphene, antimony-doped tin oxide, epoxy resin and phenolic resin in a mass ratio of 6:1.5:0.5:1:0.5.

[0049] In this invention, unless otherwise stated, the coagulation bath used in the embodiments is deionized water.

[0050] Example 1

[0051] Reference Figure 1-2 As shown, the composite fiber with infrared stealth function of the present invention includes a core layer 91, a hollow fiber layer 92, a nanofiber layer 93 and a pigment coating layer 94 arranged sequentially; the core layer 91 is liquid metal; the hollow fiber layer 92 is polyurethane / vanadium dioxide hollow composite fiber; the nanofiber layer 93 is silk fibroin / titanium dioxide nanocomposite fiber; and the pigment coating layer 94 is a metal coating.

[0052] The method for preparing the composite fiber with infrared stealth function of the present invention specifically includes the following steps:

[0053] S1. Polyurethane and vanadium dioxide are dissolved in N,N-dimethylformamide to obtain a polyurethane / vanadium dioxide spinning solution 1 with a polyurethane mass fraction of 20% and a vanadium dioxide mass fraction of 40%. The polyurethane / vanadium dioxide hollow composite fiber is formed in a coagulation bath 4 using microfluidic wet spinning technology to form a hollow fiber layer with a thickness of 1.2 mm. At the same time, liquid metal 3 (gallium indium tin alloy) is injected into the hollow fiber layer using a coaxial needle 2 to form a core layer with a radius of 0.8 mm.

[0054] The extrusion speed of the liquid metal is 4 mL / h, and the extrusion speed of the polyurethane / vanadium dioxide spinning solution is 8 mL / h.

[0055] S2. Dissolve silk fibroin and titanium dioxide in hexafluoroisopropanol to obtain a silk fibroin / titanium dioxide spinning solution with a mass fraction of 5% silk fibroin and a mass fraction of 20% titanium dioxide. Use electrospinning technology to make silk fibroin / titanium dioxide nanocomposite fibers 5, and uniformly spirally coat the surface of the hollow fiber layer treated by S1 to form a nanofiber layer with a thickness of 1 mm.

[0056] The conditions for electrospinning are as follows: injection pump speed is 1 mL / h, voltage is 15 kV, and receiving distance is 15 cm.

[0057] S3. After the fiber is treated by S2, it is heated at 60°C for 20 seconds through heating channel 6. Then, a metal coating 7 is sprayed onto the surface of the nanofiber layer through nozzle 8 to form a pigment coating layer with a thickness of 50μm, thus obtaining a composite fiber 9 with infrared stealth function.

[0058] Example 2 is basically the same as Example 1, except that the mass fraction of vanadium dioxide in the polyurethane / vanadium dioxide spinning solution is different.

[0059] S1. Polyurethane and vanadium dioxide are dissolved in N,N-dimethylformamide to obtain a polyurethane / vanadium dioxide spinning solution 1 with a polyurethane mass fraction of 20% and a vanadium dioxide mass fraction of 30%. Polyurethane / vanadium dioxide hollow composite fibers are formed in a coagulation bath 4 using microfluidic wet spinning technology to form a hollow fiber layer with a thickness of 1.2 mm. At the same time, liquid metal 3 (gallium indium tin alloy) is injected into the hollow fiber layer using a coaxial needle 2 to form a core layer with a radius of 0.8 mm.

[0060] The extrusion speed of the liquid metal is 4 mL / h, and the extrusion speed of the polyurethane / vanadium dioxide spinning solution is 8 mL / h.

[0061] S2. Dissolve silk fibroin and titanium dioxide in hexafluoroisopropanol to obtain a silk fibroin / titanium dioxide spinning solution with a mass fraction of 5% silk fibroin and a mass fraction of 20% titanium dioxide. Use electrospinning technology to make silk fibroin / titanium dioxide nanocomposite fibers 5, and uniformly spirally coat the surface of the hollow fiber layer treated by S1 to form a nanofiber layer with a thickness of 1 mm.

[0062] The conditions for electrospinning are as follows: injection pump speed is 1 mL / h, voltage is 15 kV, and receiving distance is 15 cm.

[0063] S3. After the fiber is treated by S2, it is heated at 60°C for 20 seconds through heating channel 6. Then, a metal coating 7 is sprayed onto the surface of the nanofiber layer through nozzle 8 to form a pigment coating layer with a thickness of 50μm, thus obtaining a composite fiber 9 with infrared stealth function.

[0064] Example 3 is basically the same as Example 1, except that the mass fraction of vanadium dioxide in the polyurethane / vanadium dioxide spinning solution is different.

[0065] S1. Polyurethane and vanadium dioxide are dissolved in N,N-dimethylformamide to obtain a polyurethane / vanadium dioxide spinning solution 1 with a polyurethane mass fraction of 20% and a vanadium dioxide mass fraction of 60%. Polyurethane / vanadium dioxide hollow composite fibers are formed in a coagulation bath 4 using microfluidic wet spinning technology to form a hollow fiber layer with a thickness of 1.2 mm. At the same time, liquid metal 3 (gallium indium tin alloy) is injected into the hollow fiber layer using a coaxial needle 2 to form a core layer with a radius of 0.8 mm.

[0066] The extrusion speed of the liquid metal is 4 mL / h, and the extrusion speed of the polyurethane / vanadium dioxide spinning solution is 8 mL / h.

[0067] S2. Dissolve silk fibroin and titanium dioxide in hexafluoroisopropanol to obtain a silk fibroin / titanium dioxide spinning solution with a mass fraction of 5% silk fibroin and a mass fraction of 20% titanium dioxide. Use electrospinning technology to make silk fibroin / titanium dioxide nanocomposite fibers 5, and uniformly spirally coat the surface of the hollow fiber layer treated by S1 to form a nanofiber layer with a thickness of 1 mm.

[0068] The conditions for electrospinning are as follows: injection pump speed is 1 mL / h, voltage is 15 kV, and receiving distance is 15 cm.

[0069] S3. After the fiber is treated by S2, it is heated at 60°C for 20 seconds through heating channel 6. Then, a metal coating 7 is sprayed onto the surface of the nanofiber layer through nozzle 8 to form a pigment coating layer with a thickness of 50μm, thus obtaining a composite fiber 9 with infrared stealth function.

[0070] Comparative Example 1

[0071] The process is basically the same as in Example 1, except that the mass fraction of vanadium dioxide in the polyurethane / vanadium dioxide spinning solution is 20%.

[0072] Comparative Example 2

[0073] The process is basically the same as in Example 1, except that the mass fraction of vanadium dioxide in the polyurethane / vanadium dioxide spinning solution is 70%.

[0074] Comparative Example 3

[0075] It is basically the same as Example 1, except that there is no core layer.

[0076] Comparative Example 4

[0077] It is basically the same as Example 1, except that there is no nanofiber layer.

[0078] Comparative Example 5

[0079] It is basically the same as Example 1, except that there is no pigment coating layer.

[0080] Comparative Example 6

[0081] Commercially available fabrics with infrared stealth capabilities.

[0082] Test case

[0083] The fibers of Examples 1-3 and Comparative Examples 1-6 were tested for their strength and elongation at break. The fibers of Examples 1-3 and Comparative Examples 1-5 were used to fabricate fabrics with the same specifications as Comparative Example 6, and the infrared stealth performance and breathability of the fabrics were tested. The relevant performance testing methods are as follows:

[0084] (1) Breaking stress and breaking elongation: Determined in accordance with GB / T 3916-2013 "Determination of breaking strength and breaking elongation of single yarn in packaged textiles".

[0085] (2) Infrared emissivity: Measured in accordance with GB / T 30127-2013 "Detection and Evaluation of Far-Infrared Properties of Textiles" standard;

[0086] (3) Air permeability: Determined according to GB / T 5453-1997 "Determination of air permeability of textile fabrics";

[0087] Table 1 shows the final measured performance parameters:

[0088] Table 1

[0089] Sample Fracture strength (MPa) Elongation at break (%) Infrared emissivity Air permeability (mm / s) Example 1 3.21 310 0.55 35 Example 2 3.44 332 0.63 34 Example 3 2.96 285 0.51 35 Comparative Example 1 3.53 367 0.74 35 Comparative Example 2 2.58 220 0.49 36 Comparative Example 3 2.83 289 0.57 38 Comparative Example 4 3.05 298 0.61 37 Comparative Example 5 3.14 305 0.68 40 Comparative Example 6 1.22 50 0.71 15

[0090] As shown in Table 1, and from Examples 1-3 and Comparative Example 1, although the fiber exhibits good flexibility (the higher the elongation at break, the better the flexibility), its infrared stealth performance is poor (the lower the infrared emissivity, the better the infrared stealth performance). From Examples 1-3 and Comparative Example 2, it can be seen that although the fiber possesses good infrared stealth performance, its flexibility is poor, and it cannot simultaneously possess both. From Examples 6 and Comparative Example 6, it can be seen that the flexibility of the materials in these examples is significantly improved, and their infrared stealth performance is also significantly enhanced.

[0091] In summary, the composite fiber with infrared stealth function of the present invention not only has excellent infrared stealth performance, but also good flexibility. At the same time, its preparation method has good continuity and high production efficiency.

[0092] 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 composite fiber with infrared stealth function, characterized in that, The composite fiber comprises a core layer, a hollow fiber layer, a nanofiber layer and a pigment coating layer arranged in sequence; the core layer is a liquid metal; the hollow fiber layer is a polyurethane / vanadium dioxide hollow composite fiber; the nanofiber layer is a silk fibroin / titanium dioxide nanocomposite fiber; and the pigment coating layer is a metal coating. The preparation method of the composite fiber with infrared stealth function, The preparation method comprises the following steps, S1, polyurethane / vanadium dioxide spinning solution is prepared into polyurethane / vanadium dioxide hollow composite fiber by microfluidic wet spinning technology to form a hollow fiber layer; and a coaxial needle is used to inject liquid metal into the hollow fiber layer to form a core layer; S2, silk fibroin / titanium dioxide nanocomposite fiber is prepared from silk fibroin / titanium dioxide spinning solution by electrospinning technology, and is coated on the surface of the hollow fiber layer treated in S1 to form a nanofiber layer; S3, the fiber treated in S2 is heated, and a metal coating is sprayed on the surface of the nanofiber layer to form a pigment coating layer, thereby obtaining the composite fiber with infrared stealth function.

2. The composite fiber having infrared invisibility function according to claim 1, characterized by, The liquid metal is a gallium-indium-tin alloy.

3. The composite fiber having an infrared invisibility function according to claim 1, characterized by, The metal coating is obtained by mixing copper powder, graphene, antimony-doped tin oxide, epoxy resin and phenolic resin in a mass ratio of 5-7:1-2:0.5-1:0.5-2:0.5-1.

5.

4. The composite fiber having an infrared invisibility function according to claim 1, characterized by, The radius of the core layer is 0.1mm-2mm; the thickness of the hollow fiber layer is 1mm-3mm; the thickness of the nanofiber layer is 1mm-3mm; and the thickness of the pigment coating layer is 30um-100um.

5. The composite fiber having infrared invisibility function according to claim 1, characterized by, In S1, the polyurethane / vanadium dioxide spinning solution comprises polyurethane, vanadium dioxide and a solvent A, the mass fraction of polyurethane in the polyurethane / vanadium dioxide spinning solution is 10%-30%, the mass fraction of vanadium dioxide is 30%-60%, and the solvent A is selected from N,N-dimethylformamide and / or dichloromethane.

6. The composite fiber having infrared invisibility function according to claim 1, characterized by, In S1, the extrusion speed of the liquid metal is 3mL / h-6mL / h, and the extrusion speed of the polyurethane / vanadium dioxide spinning solution is 7mL / h-10mL / h.

7. The composite fiber having an infrared invisibility function according to claim 1, characterized by, In S2, the silk fibroin / titanium dioxide spinning solution comprises silk fibroin, titanium dioxide and a solvent B, the mass fraction of silk fibroin in the silk fibroin / titanium dioxide spinning solution is 1%-10%, the mass fraction of titanium dioxide is 10%-40%, and the solvent B is selected from hexafluoroisopropanol and / or formic acid.

8. The composite fiber having an infrared invisibility function according to claim 1, characterized by, In S2, the electrospinning conditions are as follows: the speed of the injection pump is 0.5mL / h-2.5mL / h, the voltage is 10kV-15kV, and the receiving distance is 10cm-20cm.

9. The composite fiber having an infrared invisibility function according to claim 1, characterized by, In S3, the heating temperature is 50℃-80℃, and the time is 5s-30s.

Images